diff --git "a/txt-clean-pdf-without-outline-all2-onefile/LS-DYNA.txt" "b/txt-clean-pdf-without-outline-all2-onefile/LS-DYNA.txt" new file mode 100644--- /dev/null +++ "b/txt-clean-pdf-without-outline-all2-onefile/LS-DYNA.txt" @@ -0,0 +1,276355 @@ +Corporate Address +Livermore Software Technology Corporation +P. O. Box 712 +Livermore, California 94551-0712 +Support Addresses +LSTC +7374 Las Positas Road +Livermore, California 94551 +Tel: 925-449-2500 ♦ Fax: 925-449-2507 +Email: sales@lstc.com +Website: www.lstc.com +Disclaimer +LSTC +1740 West Big Beaver Road +Suite 100 +Troy, Michigan 48084 +Tel: 248-649-4728 ♦ Fax: 248-649-6328 +Copyright © 1992-2017 Livermore Software Technology Corporation. All Rights +Reserved. +LS-DYNA®, LS-OPT® and LS-PrePost® are registered trademarks of Livermore Software +Technology Corporation in the United States. All other trademarks, product names and +brand names belong to their respective owners. +LSTC reserves the right to modify the material contained within this manual without +prior notice. +The information and examples included herein are for illustrative purposes only and +are not intended to be exhaustive or all-inclusive. LSTC assumes no liability or +responsibility whatsoever for any direct of indirect damages or inaccuracies of any type +or nature that could be deemed to have resulted from the use of this manual. +Any reproduction, in whole or in part, of this manual is prohibited without the prior +written approval of LSTC. All requests to reproduce the contents hereof should be sent +to sales@lstc.com. +⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ +AES Licensing Terms +Copyright © 2001, Dr Brian Gladman < brg@gladman.uk.net>, Worcester, UK. All rights reserved. +The free distribution and use of this software in both source and binary form is allowed (with or without +changes) provided that: +1.distributions of this source code include the above copyright notice, this list of conditions and the +following disclaimer; +2.distributions in binary form include the above copyright notice, this list of conditions and the +following disclaimer in the documentation and/or other associated materials; +3.he copyright holder's name is not used to endorse products built using this software without +specific written permission. +DISCLAIMER +This software is provided 'as is' with no explicit or implied warranties in respect of any properties, +including, but not limited to, correctness and fitness for purpose. +This file contains the code for implementing the key schedule for AES (Rijndael) for block and key sizes +of 16, 24, and 32 bytes. +When defining an equation of state, the type of equation of state is specified by a +corresponding 3-digit number in the command name, e.g., *EOS_004, or equivalently, +by it’s more descriptive designation, e.g., *EOS_GRUNEISEN. The equations of state +can be used with a subset of the materials that are available for solid elements; see the +MATERIAL MODEL REFERENCE TABLES in the beginning of the *MAT section of +this Manual. *EOS_015 is linked to the type 2 thick shell element and can be used to +model engine gaskets. +The meaning associated with particular extra history variables for a subset of material +models and equations of state are tabulated at http://www.dynasupport.com/howtos- +/material/history-variables. The first three extra history variables when using an +equation of state are (1) internal energy, (2) pressure due to bulk viscosity, and (3) the +element volume from the previous time step. +TYPE 1: +*EOS_LINEAR_POLYNOMIAL +TYPE 2: +*EOS_JWL +TYPE 3: +*EOS_SACK_TUESDAY +TYPE 4: +*EOS_GRUNEISEN +TYPE 5: +*EOS_RATIO_OF_POLYNOMIALS +TYPE 6: +*EOS_LINEAR_POLYNOMIAL_WITH_ENERGY_LEAK +TYPE 7: +*EOS_IGNITION_AND_GROWTH_OF_REACTION_IN_HE +TYPE 8: +*EOS_TABULATED_COMPACTION +TYPE 9: +*EOS_TABULATED +TYPE 10: +*EOS_PROPELLANT_DEFLAGRATION +TYPE 11: +*EOS_TENSOR_PORE_COLLAPSE +TYPE 12: +*EOS_IDEAL_GAS +TYPE 14: +*EOS_JWLB +TYPE 15: +*EOS_GASKET +*EOS_MIE_GRUNEISEN +TYPE 19: +*EOS_MURNAGHAN +TYPE 21-30: +*EOS_USER_DEFINED +An additional option TITLE may be appended to all the *EOS keywords. If this option +is used then an additional line is read for each section in 80a format which can be used +to describe the equation of state. At present LS-DYNA does not make use of the title. +Inclusion of title simply gives greater clarity to input decks. +Definitions and Conventions +In order to prescribe the boundary and/or initial thermodynamic condition, manual +computations are often necessary. Conventions or definitions must be established to +simplify this process. Some basic variables are defined in the following. Since many of +these variables have already been denoted by different symbols, the notations used here +are unique in this section only! They are presented to only clarify their usage. A +corresponding SI unit set is also presented as an example. +First consider a few volumetric parameters since they are a measure of compression (or +expansion). +Volume: +Mass: +𝑉 ≈ (m3) +𝑀 ≈ (Kg) +Current specific volume (per mass): +Reference specific volume: +Relative volume: +𝜐 = += +≈ ( +𝑚3 +Kg +) +𝜐0 = +𝑉0 += +𝜌0 +≈ ( +𝑚3 +Kg +) +𝜐𝑟 = +𝑉0 += +) +(𝑉 𝑀⁄ +(𝑉0 𝑀⁄ +) += +𝜐0 += +𝜌0 +Current normalized volume increment: +𝑑𝜐 += +𝜐 − 𝜐0 += 1 − +𝜐𝑟 += 1 − +𝜌0 +𝜇 = +𝜐𝑟 +− 1 = +𝜐0 − 𝜐 += − +𝑑𝜐 += +𝜌0 +− 1 +Sometimes another volumetric parameter is used: +𝜌0 +𝜐0 +𝜂 = += +Thus, the relation between 𝜇 and 𝜂 is, +𝜇 = +𝜐0 − 𝜐 += 𝜂 − 1 +The following table summarizes these volumetric parameters. +VARIABLES +COMPRESSION +NO LOAD +EXPANSION +𝜐𝑟 = +𝜐0 += +𝜌0 +𝜂 = +𝜐𝑟 += +𝜐0 += +𝜌0 +𝜇 = +𝜐𝑟 +− 1 = 𝜂 − 1 +< 1 +> 1 +> 0 +V0 – Initial Relative Volume +1 +1 +0 +> 1 +< 1 +< 0 +There are 3 definitions of density that must be distinguished from each other: +𝜌0 = 𝜌ref += Density at nominal reference +⁄ +state, usually non-stress or non-deformed state. +𝜌∣𝑡=0 = Density at time 0 +𝜌 = Current density +Recalling the current relative volume +𝜐𝑟 = +𝜌0 += +𝜐0 +, +at time = 0 the relative volume is +𝜐𝑟0 = 𝜐𝑟|𝑡=0 = +𝜌0 +𝜌∣𝑡=0 += +𝜐|𝑡=0 +𝜐0 +. +Generally, the V0 input parameter in an *EOS card refers to this 𝜐𝑟0. 𝜌0 is generally the +density defined in the *MAT card. Hence, if a material is mechanically compressed at +(𝜐0 ≠ 𝑉0). +The “reference” state is a unique state with respect to which the material stress tensor is +computed. Therefore 𝜐0 is very critical in computing the pressure level in a material. +Incorrect choice of 𝜐0 would lead to incorrect pressure computed. In general, 𝜐0 is +chosen such that at zero compression or expansion, the material should be in +equilibrium with its ambient surrounding. In many of the equations shown in the EOS +section, 𝜇 is frequently used as a measure of compression (or expansion). However, the +users must clearly distinguish between 𝜇 and 𝜐𝑟0. +E0 – Internal Energy +Internal energy represents +component) of a system. One definition for internal energy is +thermal energy state +the +(temperature dependent +𝐸 = 𝑀𝐶𝑣𝑇 ≈ (Joule) +Note that the capital “𝐸” here is the absolute internal energy. It is not the same as that +used in the subsequent *EOS keyword input, or some equations shown for each *EOS +card. This internal energy is often defined with respect to a mass or volume unit. +Internal energy per unit mass (also called specific internal energy): +𝑒 = += 𝐶𝑉𝑇 ≈ ( +Joule +Kg +) +Internal energy per unit current volume: +𝑒𝑉 = +𝐶𝑉𝑇 = 𝜌𝐶𝑉𝑇 = +𝐶𝑉𝑇 +≈ ( +Joule +m3 = +m2) +Internal energy per unit reference volume: +𝑒𝑉0 = +𝑉0 +𝐶𝑣𝑇 = 𝜌0𝐶𝑣𝑇 = +𝐶𝑣𝑇 +𝜐0 +≈ ( +Joule +m3 = +m2) +𝑒𝑉0 typically refers to the capital “E” shown in some equations under this “EOS” +section. Hence the initial “internal energy per unit reference volume”, E0, a keyword input +parameter in the *EOS section can be computed from +To convert from 𝑒𝑉0 to 𝑒𝑉, simply divide 𝑒𝑉0 by 𝜐𝑟 +𝑒𝑉0∣ +𝑡=0 += 𝜌0𝐶𝑉𝑇|𝑡=0 +𝑒𝑉 = 𝜌𝐶𝑉𝑇 = [𝜌0𝐶𝑉𝑇] +𝜌0 += +𝑒𝑉0 +𝜐𝑟 +A thermodynamic state of a homogeneous material, not undergoing any chemical +reactions or phase changes, may be defined by two state variables. This relation is +generally called an equation of state. For example, a few possible forms relating +pressure to two other state variables are +𝑃 = 𝑃(𝜌, 𝑇) = 𝑃(𝜐, 𝑒) = 𝑃(𝜐𝑟, 𝑒𝑉) = 𝑃(𝜇, 𝑒𝑉0) +The last equation form is frequently used to compute pressure. The EOS for solid phase +materials is sometimes partitioned into 2 terms, a cold pressure and a thermal pressure +𝑃 = 𝑃𝑐(𝜇) + 𝑃𝑇(𝜇, 𝑒𝑉0) +𝑃𝑐(𝜇) is the cold pressure hypothetically evaluated along a 0-degree-Kelvin isotherm. +This is sometimes called a 0-K pressure-volume relation or cold compression curve. +𝑃𝑇(𝜇, 𝑒𝑉0) is the thermal pressure component that depends on both volumetric +compression and thermal state of the material. +Different forms of the EOS describe different types of materials and how their +volumetric compression (or expansion) behaviors. The coefficients for each EOS model +come from data-fitting, phenomenological descriptions, or derivations based on +classical thermodynamics, etc. +Linear Compression +In low pressure processes, pressure is not significantly affected by temperature. When +volumetric compression is within an elastic linear deformation range, a linear bulk +modulus may be used to relate volume changes to pressure changes. Recalling the +definition of an isotropic bulk modulus is [Fung 1965], +This may be rewritten as +Δ𝜐 += − +. +𝑃 = 𝐾 [− +Δ𝜐 +] = 𝐾𝜇. +The bulk modulus, 𝐾, thus is equivalent to 𝐶1 in *EOS_LINEAR_POLYNOMIAL when +all other coefficients are zero. This is a simplest form of an EOS. To initialize a pressure +for such a material, only 𝜐𝑟0 must be defined. +Initial Conditions +In general, a thermodynamic state must be defined by two state variables. The need to +specify 𝜐𝑟0 and/or 𝑒𝑉0∣ + depends on the form of the EOS chosen. The user should +review the equation term-by-term to establish what parameters to be initialized. +𝑡=0 +or 𝜐𝑟0. Consider two possibilities (1) 𝑇|𝑡=0 is defined or +assumption on either 𝑒𝑉0∣ +assumed from which 𝑒𝑉0∣ + may be computed, or (2) 𝜌∣𝑡=0 is defined or assumed from +𝑡=0 +which 𝜐𝑟0 may be obtained. +𝑡=0 +When to Use EOS +For small strains considerations, a total stress tensor may be partitioned into a +deviatoric stress component and a mechanical pressure. +𝜎𝑖𝑗 = 𝜎𝑖𝑗 +′ + +𝜎𝑘𝑘 +𝛿𝑖𝑗 = 𝜎𝑖𝑗 +′ − 𝑃𝛿𝑖𝑗 +𝑃 = − +𝜎𝑘𝑘 +The pressure component may be written from the diagonal stress components. +Note that +𝜎𝑘𝑘 +3 = +[𝜎11+𝜎22+𝜎33] + is positive in tension while P is positive in compression. +Similarly, the total strain tensor may be partitioned into a deviatoric strain component +(volume-preserving deformation) and a volumetric deformation. +𝜀𝑘𝑘 +𝜀𝑘𝑘 +3 is called the mean normal strain, and 𝜀𝑘𝑘 is called the dilatation or volume +𝜀𝑖𝑗 = 𝜀𝑖𝑗 +′ + +𝛿𝑖𝑗 +where +strain (change in volume per unit initial volume) +𝜀𝑘𝑘 = +𝑉 − 𝑉0 +𝑉0 +′ ) as a +Roughly speaking, a typical convention may refer to the relation 𝜎𝑖𝑗 +“constitutive equation”, and 𝑃 = 𝑓 (𝜇, 𝑒𝑉0) as an EOS. The use of an EOS may be +omitted only when volumetric deformation is very small, and |𝑃| A ∣𝜎𝑖𝑗 +′ = 𝑓 (𝜀𝑖𝑗 +′ ∣. +A Note About Contact When Using an Equation of State +When a part includes an equation of state, it is important that the initial geometry of +that part not be perturbed by the contact algorithm. Such perturbation can arise due to +initial penetrations in the contact surfaces but can usually be avoided by setting the +variable IGNORE to 1 or 2 in the *CONTACT input or by using a segment based contact +(SOFT = 2). +This is Equation of state Form 1. +*EOS_LINEAR_POLYNOMIAL +Purpose: +thermodynamic state of the material by defining E0 and V0 below. + Define coefficients for a linear polynomial EOS, and initialize the + Card 1 +1 +Variable +EOSID +Type +A8 + Card 2 +Variable +1 +E0 +Type +F + VARIABLE +EOSID +C0 +C1 +⋮ +C6 +E0 +V0 +3 +C1 +F +3 +4 +C2 +F +4 +5 +C3 +F +5 +6 +C 4 +F +6 +7 +C5 +F +7 +8 +C6 +F +8 +2 +C0 +F +2 +V0 +F +DESCRIPTION +Equation of state ID, a unique number or label not exceeding 8 +characters must be specified. +The 0th polynomial equation coefficient. +The 1st polynomial equation coefficient (when used by itself, this +is the elastic bulk modulus, i.e. it cannot be used for deformation +that is beyond the elastic regime). +⋮ +The 6th polynomial equation coefficient. +Initial internal energy per unit reference volume . +Initial relative volume . +*EOS +1. The linear polynomial equation of state is linear in internal energy. The +pressure is given by: +𝑃 = 𝐶0 + 𝐶1𝜇 + 𝐶2𝜇2 + 𝐶3𝜇3 + (𝐶4 + 𝐶5𝜇 + 𝐶6𝜇2)𝐸. +𝐶2𝜇2 + is the ratio +where terms +of current density to reference density. 𝜌 is a nominal or reference density +defined in the *MAT_NULL card. +are set to zero if 𝜇 < 0, 𝜇 = +− 1, and +and +𝐶6𝜇2 +𝜌0 +𝜌0 +The linear polynomial equation of state may be used to model gas with the +gamma law equation of state. This may be achieved by setting: +𝐶0 = 𝐶1 = 𝐶2 = 𝐶3 = 𝐶6 = 0 +and +where +𝐶4 = 𝐶5 = 𝛾 − 1 +𝛾 = +𝐶𝑝 +𝐶𝑣 +is the ratio of specific heats. Pressure for a perfect gas is then given by: +𝑝 = (𝛾 − 1) +𝜌0 +𝐸 +E has the unit of pressure (where 𝜌 and 𝜌) +2. When 𝐶0 = 𝐶1 = 𝐶2 = 𝐶3 = 𝐶6 = 0, it does not necessarily mean that the initial +pressure is zero, 𝑃0 ≠ 𝐶0! The initial pressure depends the values of all the +coefficients and on 𝜇∣𝑡=0 and 𝐸∣𝑡=0. The pressure in a material is computed from +the whole equation above, 𝑃 = 𝑃(μ, 𝐸). It is always preferable to initialize the +initial condition based on 𝜇∣𝑡=0 and 𝐸∣𝑡=0. The use of 𝐶0 = 𝐶1 = 𝐶2 = 𝐶3 = 𝐶6 = +0 must be done with caution as it may change the form and behavior of the +material. The safest way is to use the whole EOS equation to manually check +for the pressure value. For example, for ideal gas, for ideal gas, only 𝐶4 and 𝐶5 +are nonzero, 𝐶4 = 𝐶5 = 𝛾 − 1 and all other coefficients 𝐶0 = 𝐶1 = 𝐶2 = 𝐶3 = +𝐶6 = 0 to satisfy the perfect gas equation form. +3. V0 and E0 defined in this card must be the same as the time-zero ordinates for +the 2 load curves defined in the *BOUNDARY_AMBIENT_EOS card, if it is +used. This is so that they would both consistently define the same initial state +for a material. +This is Equation of state Form 2. +Available options are: + +AFTERBURN +*EOS_JWL + Card 1 +1 +Variable +EOSID +Type +A8 +2 +A +F +3 +B +F +4 +R1 +F +5 +R2 +F +6 +OMEG +F +7 +E0 +F +8 +VO +F +Afterburn card. Additional card for afterburn option with OPT = 1 or 2. + Card 2 +1 +Variable +OPT +Type +F +2 +QT +F +3 +T1 +F +4 +T2 +F +5 +6 +7 +8 +Afterburn card. Additional card for afterburn option with OPT = 3. + Card 2 +1 +Variable +OPT +Type +F +2 +Q0 +F +3 +QA +F +4 +QM +5 +6 +7 +8 +QN +CONM +CONL +CONT +F +F +F +1. +F +1. +F +1. +Default +none +none +none +0.5 +1/6 + VARIABLE +EOSID +1-18 (EOS) +DESCRIPTION +Equation of state ID, a unique number or label not exceeding 8 +DESCRIPTION +*EOS +A +B +R1 +R2 +𝐴, See equation in Remarks. +𝐵, See equation in Remarks. +𝑅1, See equation in Remarks. +𝑅2, See equation in Remarks. +OMEG +𝜔, See equation in Remarks. +E0 +V0 +OPT +QT +T1 +T2 +Q0 +QA +QM +QN +Detonation energy per unit volume and initial value for 𝐸. See +equation in Remarks. +Initial relative volume, which gives the initial value for 𝑉. See +equation in Remarks. +Afterburn option + EQ.0.0: No afterburn energy (Standard EOS_JWL) + EQ.1.0: Constant rate of afterburn energy added between times + T1 and T2 + EQ.2.0: Linearly-increasing rate of afterburn energy added + between times T1 and T2 + EQ.3.0: Miller’s extension for afterburn energy +Afterburn energy per unit volume +(OPT = 1,2) +for simple afterburn +Start time of energy addition for simple afterburn +End time of energy addition for simple afterburn +Afterburn energy per unit volume for Miller’s extension +(OPT = 3) +Energy release constant 𝑎 for Miller’s extension +Energy release exponent 𝑚 for Miller’s extension +Pressure exponent 𝑛 for Miller’s extension +CONM +CONL +CONT +Remarks: +*EOS_JWL +DESCRIPTION +GT.0.0: Mass conversion factor from model units to calibration +units + for Miller’s extension +LT.0.0: Use predefined factors to convert model units to +published + calibration units of g, cm, µs. Choices for model units are: + EQ.-1.0: g, mm, ms + EQ.-2.0: g, cm, ms + EQ.-3.0: kg, m, s + EQ.-4.0: kg, mm, ms + EQ.-5.0: metric ton, mm, s + EQ.-6.0: lbf-s2/in, in, s + EQ.-7.0: slug, ft, s +CONM.GT.0.0: Length conversion factor from model units to + calibration units for Miller’s extension +CONM.LT.0.0: Ignored +CONM.GT.0.0: Time conversion factor from model units to + calibration units for Miller’s extension +CONM.LT.0.0: Ignored +The JWL equation of state defines the pressure as +𝑝 = 𝐴 (1 − +𝑅1𝑉 +) 𝑒−𝑅1𝑉 + 𝐵 (1 − +𝑅2𝑉 +) 𝑒−𝑅2𝑉 + +𝜔𝐸 +, +and is usually used for detonation products of high explosives. +A, B, and E0 have units of pressure. R1, R2, OMEG, and V0 are dimensionless. It is +recommended that a unit system of gram, centimeter, microsecond be used when a +model includes high explosive(s). In this consistent unit system, pressure is in Mbar. +When this equation of state is used with *MAT_HIGH_EXPLOSIVE_BURN in which +the variable BETA is set to 0 or 2, the absolute value of the history variable labeled as +“effective plastic strain” is the explosive lighting time. This lighting time takes into +account shadowing if invoked . +There are four additional history variables for the JWL equation of state. Those history +variables are internal energy, bulk viscosity in units of pressure, volume, and burn +fraction, respectively. To output the history variables, set the variable NEIPH in +*DATABASE_EXTENT_BINARY. +The AFTERBURN option allows the addition of afterburn energy 𝑄 to the calculation of +pressure by replacing 𝐸 in the above equation with (𝐸 + 𝑄), i.e. the last term on the +right-hand side becomes +𝜔(𝐸 + 𝑄) +The simple afterburn option adds the energy at a constant rate (OPT = 1) or a linearly- +increasing rate (OPT = 2) between times T1 and T2 such that the total energy added per +unit volume at time T2 is the specified energy QT. +For the Miller’s extension model (OPT = 3), the afterburn energy is added via a time- +dependent growth term +𝑑𝜆 +𝑑𝑡 += 𝑎(1 − 𝜆)𝑚𝑝𝑛, 𝑄 = 𝜆𝑄0 +Here, 𝑚, 𝑛, and 𝜆 are dimensionless, with 𝜆 a positive fraction less than 1.0. The +parameter 𝑎 has units consistent with this growth equation, and 𝑄0 has units of +pressure. +The values for 𝑄0, 𝑎, 𝑚, 𝑛 published by Miller and Guirguis (1993) are calibrated in the +units of g, cm, µs, with the consistent pressure unit of Mbar, though in principle any +consistent set of units may be used for calibration. The factors CONM, CONL, and +CONT convert the unit system of the model being analyzed to the calibration unit +system in which the Miller’s extension parameters are specified, e.g. a mass value in +model units may be multiplied by CONM to obtain the corresponding value in +calibration units. These conversion factors allow consistent evaluation of the growth +equation in the calibrated units. For user convenience, predefined conversion factors +are provided for converting various choices for the model units system to the +calibration unit system used by Miller and Guirguis. +The AFTERBURN option introduces an additional 5th history variable that records the +added afterburn energy 𝑄 for simple afterburn (OPT = 1,2), but contains the growth +term 𝜆 when using the Miller’s extension model (OPT = 3). +This is Equation of state Form 3. +*EOS_SACK_TUESDAY + Card 1 +1 +Variable +EOSID +Type +A8 +2 +A1 +F +3 +A2 +F +4 +A3 +F +5 +B1 +F +6 +B2 +F +7 +E0 +F +8 +V0 +F + VARIABLE +EOSID +DESCRIPTION +Equation of state ID, a unique number or label not exceeding 8 +characters must be specified. +Ai, Bi +Constants in the equation of state +E0 +V0 +Initial internal energy +Initial relative volume +Remarks: +The Sack equation of state defines pressure as +𝑝 = +𝐴3 +𝑉𝐴1 +𝑒−𝐴2𝑉 (1 − +𝐵1 +) + +𝐵2 +𝐸 +and is used for detonation products of high explosives. +This is Equation of state Form 4. +*EOS + Card 1 +1 +Variable +EOSID +Type +A8 + Card 2 +Variable +1 +V0 +Type +F + VARIABLE +EOSID +2 +C +F +2 +3 +S1 +F +3 +4 +S2 +F +4 +5 +S3 +F +5 +6 +GAMAO +F +6 +7 +A +F +7 +8 +E0 +F +8 +DESCRIPTION +Equation of state ID, a unique number or label not exceeding 8 +characters must be specified. +C, Si, GAMMA0 +Constants in the equation of state +First order volume correction coefficient +Initial internal energy +Initial relative volume +A +E0 +V0 +Remarks: +The Gruneisen equation of state with cubic shock-velocity as a function of particle- +velocity 𝑣𝑠(𝑣𝑝) defines pressure for compressed materials as +𝜌0𝐶2𝜇[1 + (1 − +)𝜇 − 𝑎 +𝜇2] +𝑝 = +𝛾0 +𝜇2 +𝜇 + 1 +− 𝑆3 +𝜇3 +(𝜇 + 1)2] +[1 − (𝑆1 − 1)𝜇 − 𝑆2 +and for expanded materials as +2 + (𝛾0 + 𝑎𝜇)𝐸. +𝑝 = 𝜌0𝐶2𝜇 + (𝛾0 + 𝑎𝜇)𝐸. +where C is the intercept of the 𝑣𝑠(𝑣𝑝) curve (in velocity units); S1, S2, and S3 are the +unitless coefficients of the slope of the 𝑣𝑠(𝑣𝑝) curve; γ +0 is the unitless Gruneisen gamma; +a is the unitless, first order volume correction to γ +0; and +𝜇 = +𝜌0 +− 1. +This is Equation of state Form 5. +*EOS + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EOSID +Type +A8 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +A10 +Type +F +A11 +F +A12 +F +A13 +F + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +A20 +Type +F +A21 +F +A22 +F +A23 +F + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +A30 +Type +F +A31 +F +A32 +F +A33 +F + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +A40 +Type +F +A41 +F +A42 +F +A43 +Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +A50 +Type +F +A51 +F +A52 +F +A53 +F + Card 7 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +A60 +Type +F +A61 +F +A62 +F +A63 +F + Card 8 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +A70 +Type +F +A71 +F +A72 +F +A73 +F + Card 9 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +A14 +Type +F +A24 +F + Card 10 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ALPH +Type +F +BETA +F +E0 +F +V0 +F + VARIABLE +EOSID +DESCRIPTION +Equation of state ID, a unique number or label not exceeding 8 +characters must be specified. +Aij +Polynomial coefficients +VARIABLE +DESCRIPTION +α +β +Initial internal energy +Initial relative volume +ALPHA +BETA +E0 +V0 +Remarks: +The ratio of polynomials equation of state defines the pressure as +where +𝑝 = +𝐹1 + 𝐹2𝐸 + 𝐹3𝐸2 + 𝐹4𝐸3 +𝐹5 + 𝐹6𝐸 + 𝐹7𝐸2 +(1 + 𝛼𝜇) +𝐹𝑖 = ∑ 𝐴𝑖𝑗𝜇𝑗 +𝑗=0 +, +𝑛 = { +𝑖 < 3 +𝑖 ≥ 3 +𝜌0 +′ = 𝐹1 + 𝛽𝜇2. By setting coefficient 𝐴10 = 1.0, +In expanded elements 𝐹1 is replaced by 𝐹1 +the delta-phase pressure modeling for this material will be initiated. The code will reset +it to 0.0 after setting flags. +− 1 +𝜇 = +*EOS_LINEAR_POLYNOMIAL_WITH_ENERGY_LEAK +This is Equation of state Form 6. + Define coefficients for a linear polynomial EOS, and initialize the +Purpose: +thermodynamic +state of the material by defining E0 and V0 below. Energy deposition is prescribed via a +curve. + Card 1 +1 +Variable +EOSID +Type +A8 + Card 2 +Variable +1 +E0 +Type +F + VARIABLE +EOSID +4 +C2 +F +4 +5 +C3 +F +5 +6 +C4 +F +6 +7 +C5 +F +7 +8 +C6 +F +8 +2 +C0 +F +2 +V0 +F +3 +C1 +F +3 +LCID +I +DESCRIPTION +Equation of state ID, a unique number or label not exceeding 8 +characters must be specified. +Ci +E0 +V0 +Constants in the equation of state +Initial internal energy +Initial relative volume +LCID +Load curve ID defining the energy deposition rate. +Remarks: +This polynomial equation of state, linear in the internal energy per initial volume, 𝐸, is +given by +𝑝 = 𝐶0 + 𝐶1𝜇 + 𝐶2𝜇2 + 𝐶3𝜇3 + (𝐶4 + 𝐶5𝜇 + 𝐶6𝜇2)𝐸 +in which 𝐶1, 𝐶2, 𝐶3, 𝐶4, 𝐶5, and 𝐶6 are user defined constants and +where 𝑉 is the relative volume. In expanded elements, we set the coefficients of 𝜇2 to +zero, i.e., +− 1 . +𝜇 = +Internal energy, 𝐸, is increased according to an energy deposition rate versus time curve +whose ID is defined in the input. +𝐶2 = 𝐶6 = 0 +*EOS_IGNITION_AND_GROWTH_OF_REACTION_IN_HE +This is Equation of state Form 7. + Card 1 +1 +Variable +EOSID +Type +A8 + Card 2 +Variable +1 +R2 +Type +F + Card 3 +1 +2 +A +F +2 +R3 +F +2 +3 +B +F +3 +R5 +F +3 +4 +5 +6 +XP1 +XP2 +FRER +F +5 +F +6 +7 +G +F +7 +8 +R1 +F +8 +FMXIG +FREQ +GROW1 +EM +F +5 +F +6 +F +7 +F +8 +F +4 +R6 +F +4 +Variable +AR1 +ES1 +CVP +CVR +EETAL +CCRIT +ENQ +TMP0 +Type +F + Card 4 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +GROW2 +AR2 +ES2 +EN +FMXGR +FMNGR +Type +F +F +F +F +F +F + VARIABLE +EOSID +DESCRIPTION +Equation of state ID, a unique number or label not exceeding 8 +characters must be specified. +A +B +Product JWL constant +Product JWL constant +XP1 +Product JWL constant +VARIABLE +DESCRIPTION +XP2 +FRER +G +R1 +R2 +R3 +R5 +R6 +Product JWL constant +Constant in ignition term of reaction equation +𝜔𝐶𝑣 of product +Unreacted JWL constant +Unreacted JWL constant +𝜔𝐶𝑣 of unreacted explosive +Unreacted JWL constant +Unreacted JWL constant +FMXIG +Maximum F for ignition term +FREQ +Constant in ignition term of reaction equation +GROW1 +Constant in growth term of reaction equation +EM +AR1 +ES1 +CVP +CVR +Constant in growth term of reaction equation +Constant in growth term of reaction equation +Constant in growth term of reaction equation +Heat capacity of reaction products +Heat capacity of unreacted HE +EETAL +Constant in ignition term of reaction equation +CCRIT +Constant in ignition term of reaction equation +ENQ +TMP0 +Heat of reaction +Initial temperature (°K) +GROW2 +Constant in completion term of reaction equation +AR2 +ES2 +EN +Constant in completion term of reaction equation +Constant in completion term of reaction equation +Constant in completion term of reaction equation +VARIABLE +DESCRIPTION +FMXGR +Maximum F for growth term +FMNGR +Maximum F for completion term +Remarks: +Equation of State Form 7 is used to calculate the shock initiation (or failure to initiate) +and detonation wave propagation of solid high explosives. It should be used instead of +the ideal HE burn options whenever there is a question whether the HE will react, there +is a finite time required for a shock wave to build up to detonation, and/or there is a +finite thickness of the chemical reaction zone in a detonation wave. At relatively low +initial pressures (<2-3 GPa), this equation of state should be used with material type 10 +for accurate calculations of the unreacted HE behavior. At higher initial pressures, +material type 9 can be used. A JWL equation of state defines the pressure in the +unreacted explosive as +𝑃𝑒 = 𝑟1𝑒−𝑟5𝑉𝑒 + 𝑟2𝑒−𝑟6𝑉𝑒 + 𝑟3 +𝑇𝑒 +𝑉𝑒 +, +(𝑟3 = 𝜔𝑒Cvr) +where 𝑉𝑒 and 𝑇𝑒 are the relative volume and temperature, respectively, of the unreacted +explosive. Another JWL equation of state defines the pressure in the reaction products +as +𝑃𝑝 = 𝑎𝑒−𝑥𝑝1𝑉𝑝 + 𝑏𝑒−𝑥𝑝2𝑉𝑝 + +𝑔𝑇𝑝 +𝑉𝑝 +, +(𝑔 = 𝜔𝑝Cvp) +where 𝑉𝑝 and 𝑇𝑝 are the relative volume and temperature, respectively, of the reaction +products. As the chemical reaction converts unreacted explosive to reaction products, +these JWL equations of state are used to calculate the mixture of unreacted explosive +and reaction products defined by the fraction reacted F(F = O implies no reaction, F = 1 +implies complete reaction). The temperatures and pressures are assumed to be equal +(𝑇𝑒 = 𝑇𝑝, 𝑝𝑒 = 𝑝𝑝) and the relative volumes are additive, i.e., +𝑉 = (1 − 𝐹)𝑉𝑒 + 𝐹𝑉𝑝 +The chemical reaction rate for conversion of unreacted explosive to reaction products +consists of three physically realistic terms: an ignition term in which a small amount of +explosive reacts soon after the shock wave compresses it; a slow growth of reaction as +this initial reaction spreads; and a rapid completion of reaction at high pressure and +temperature. The form of the reaction rate equation is +Ignition +⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞ +−1 − 1 − CCRIT)EETAL += FREQ × (1 − 𝐹)FRER(𝑉𝑒 +Growth +⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞ ++ GROW1 × (1 − 𝐹)ES1𝐹AR1𝑝EM +𝜕𝐹 +𝜕𝑡 ++ GROW2 × (1 − 𝐹)ES2𝑓 AR2𝑝EN +⏟⏟⏟⏟⏟⏟⏟⏟⏟⏟⏟⏟⏟⏟⏟ +Completion +The ignition rate is set equal to zero when 𝐹 ≥ FMXIG, the growth rate is set equal to +zero when 𝐹 ≥ FMXGR, and the completion rate is set equal to zero when 𝐹 ≤ FMNGR. +Details of the computational methods and many examples of one and two dimensional +shock initiation and detonation wave calculation can be found in the references +(Cochran and Chan [1979], Lee and Tarver [1980]). + Unfortunately, sufficient +experimental data has been obtained for only two solid explosives to develop very +reliable shock initiation models: PBX-9504 (and the related HMX-based explosives LX- +14,LX-10,LX-04, etc.) and LX-17 (the insensitive TATB-based explosive). Reactive flow +models have been developed for other explosives (TNT, PETN, Composition B, +propellants, etc.) but are based on very limited experimental data. +When this EOS is used with *MAT_009, history variables 4, 7, 9, and 10 are temperature, +burn fraction, 1/𝑉𝑒, and 1/𝑉𝑝, respectively. When used with *MAT_010, those histories +variables are incremented by 1, i.e., history variables 5, 8, 10, and 11 are temperature, +burn fraction, 1/𝑉𝑒, and 1/𝑉𝑝, respectively. See NEIPH in *DATABASE_EXTENT_BI- +NARY if these output variables are desired in the databases for post-processing. +*EOS_TABULATED_COMPACTION +This is Equation of state Form 8. + Card 1 +1 +2 +Variable +EOSID +GAMA +Type +A8 +F +3 +E0 +F +4 +V0 +F +5 +6 +7 +8 +LCC +LCT +LCK +I +I +I +Parameter Card Pairs. Include one pair of the following two cards for each of +VAR = 𝜀𝑣𝑖 +, 𝐶𝑖, 𝑇𝑖, and 𝐾𝑖. These cards consist of four additional pairs for a total of 8 +additional cards. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +Variable +[VAR]1 +[VAR]2 +[VAR]3 +[VAR]4 +[VAR]5 +Type +F +F +F +F +F + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +Variable +[VAR]6 +[VAR]7 +[VAR]8 +[VAR]9 +[VAR]10 +Type +F +F +F +F +F + VARIABLE +EOSID +DESCRIPTION +Equation of state ID, a unique number or label not exceeding 8 +characters must be specified. +GAMA +𝛾, (unitless), see equation in Remarks. +E0 +V0 +Initial internal energy per unit reference volume (force per unit +area). +Initial relative volume (unitless). +VARIABLE +LCC +DESCRIPTION +Load curve defining tabulated function 𝐶. See equation in +Remarks. The abscissa values of LCC, LCT and LCK must be +negative of the volumetric strain in monotonically increasing +order, in contrast to the convention in EOS_9. The definition +can extend into the tensile regime. +LCT +Load curve defining tabulated function 𝑇. See equation in +Remarks. +LCK +Load curve defining tabulated bulk modulus. +𝜀𝑣1, 𝜀𝑣2 +, …, 𝜀𝑣𝑁 +Volumetric strain, ln(𝑉). The first abscissa point, EV1, must be +0.0 or positive if the curve extends into the tensile regime with +subsequent points decreasing monotonically. +𝐶1, 𝐶2, …, 𝐶𝑁 +𝐶(𝜀𝑉), (units = force per unit area), see equation in Remarks. +𝑇1, 𝑇2, …, 𝑇𝑁 +𝑇(𝜀𝑉), (unitless), see equation in Remarks. +𝐾1, 𝐾2, …, 𝐾𝑁 +Bulk unloading modulus (units = force per unit area). +v6 +v5 +v4 +v3 ε +v2 +v1 +ln(V/V0) +Figure EOS8-1. Pressure versus volumetric strain curve for Equation of state +Form 8 with compaction. In the compacted states the bulk unloading modulus +depends on the peak volumetric strain. Volumetric strain values should be +input with correct sign (negative in compression) and in descending order. +Pressure is positive in compression. + VARIABLE +DESCRIPTION +Remarks: +The tabulated compaction model is linear in internal energy. Pressure is defined by +𝑝 = 𝐶(𝜀𝑉) + 𝛾 𝑇(𝜀𝑉)𝐸 +in the loading phase. The volumetric strain, 𝜀𝑉 is given by the natural logarithm of the +relative volume 𝑉. Unloading occurs along the unloading bulk modulus to the +pressure cutoff. The pressure cutoff, a tension limit, is defined in the material model +definition. Reloading always follows the unloading path to the point where unloading +began, and continues on the loading path, see Figure EOS8-1. Up to 10 points and as +few as 2 may be used when defining the tabulated functions. LS-DYNA will +extrapolate to find the pressure if necessary. +This is Equation of state Form 9. +*EOS + Card 1 +1 +2 +Variable +EOSID +GAMA +Type +A8 +F +3 +E0 +F +4 +V0 +F +5 +6 +7 +8 +LCC +LCT +I +I +Parameter Card Pairs. Include one pair of the following two cards for each of +VAR = 𝜀𝑉𝑖 +, 𝐶𝑖, 𝑇𝑖. These cards consist of three additional pairs for a total of 6 additional +cards. These cards are not required if LCC and LCT are specified. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +Variable +[VAR]1 +[VAR]2 +[VAR]3 +[VAR]4 +[VAR]5 +Type +F +F +F +F +F + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +Variable +[VAR]6 +[VAR]7 +[VAR]8 +[VAR]9 +[VAR]10 +Type +F +F +F +F +F + VARIABLE +EOSID +DESCRIPTION +Equation of state ID, a unique number or label not exceeding 8 +characters must be specified. +GAMA +𝛾, (unitless) see equation in Remarks. +E0 +V0 +Initial internal energy per unit reference volume (force per unit +area). +Initial relative volume (unitless). +VARIABLE +DESCRIPTION +LCC +LCT +Load curve defining tabulated function 𝐶. See equation in +Remarks. The abscissa values of LCC and LCT must increase +monotonically. The definition can extend into the tensile regime. +Load curve defining tabulated function 𝑇. See equation in +Remarks. +𝜀𝑉1, 𝜀𝑉2, …, 𝜀𝑉𝑁 +Volumetric strain, ln(𝑉), where 𝑉 is the relative volume. The +first abscissa point, EV1, must be 0.0 or positive if the curve +extends into the tensile regime with subsequent points decreasing +monotonically. +𝐶1, 𝐶2, …, 𝐶𝑁 +Tabulated points for function 𝐶 (force per unit area). +𝑇1, 𝑇2, …, 𝑇𝑁 +Tabulated points for function 𝑇 (unitless). +Remarks: +The tabulated equation of state model is linear in internal energy. Pressure is defined +by +𝑃 = 𝐶(𝜀𝑉) + 𝛾𝑇(𝜀𝑉)𝐸 +The volumetric strain, 𝜀𝑉 is given by the natural logarithm of the relative volume 𝑉. Up +to 10 points and as few as 2 may be used when defining the tabulated functions. LS- +DYNA will extrapolate to find the pressure if necessary. +*EOS_PROPELLANT_DEFLAGRATION +This Equation of state (10) has been added to model airbag propellants. + Card 1 +1 +Variable +EOSID +Type +A8 + Card 2 +Variable +Type + Card 3 +Variable +1 +G +F +1 +R6 +2 +A +F +2 +R1 +F +2 +3 +B +F +3 +R2 +F +3 +4 +5 +6 +7 +8 +XP1 +XP2 +FRER +F +F +4 +R3 +F +4 +5 +R5 +F +5 +F +6 +7 +8 +6 +7 +8 +FMXIG +FREQ +GROW1 +EM +Type +F + Card 4 +1 +F +2 +F +3 +F +4 +F +5 +6 +7 +8 +Variable +AR1 +ES1 +CVP +CVR +EETAL +CCRIT +ENQ +TMP0 +Type +F + Card 5 +1 +F +2 +F +3 +F +4 +F +5 +6 +7 +8 +Variable +GROW2 +AR2 +ES2 +EN +FMXGR +FMNGR +Type +F +F +F +F +F +EOSID +*EOS_PROPELLANT_DEFLAGRATION +DESCRIPTION +Equation of state ID, a unique number or label not exceeding 8 +characters must be specified. +A +B +XP1 +XP2 +Product JWL coefficient +Product JWL coefficient +Product JWL coefficient +Product JWL coefficient +FRER +Unreacted Co-volume +G +R1 +R2 +R3 +R5 +R6 +FMXIG +FREQ +Product 𝜔𝐶𝑣 +Unreacted JWL coefficient +Unreacted JWL coefficient +Unreacted 𝜔𝐶𝑣 +Unreacted JWL coefficient +Unreacted JWL coefficient +Initial Fraction Reacted 𝐹0 +Initial Pressure 𝑃0 +GROW1 +First burn rate coefficient +EM +AR1 +ES1 +CVP +CVR +Pressure Exponent (1st term) +Exponent on 𝐹 (1st term) +Exponent on (1 − 𝐹) (1st term) +Heat capacity 𝐶𝑣 for products +Heat capacity 𝐶𝑣 for unreacted material +EETAL +Extra, not presently used +CCRIT +Product co-volume +ENQ +Heat of Reaction +VARIABLE +DESCRIPTION +TMP0 +Initial Temperature (298°K) +GROW2 +Second burn rate coefficient +AR2 +ES2 +EN +Exponent on 𝐹 (2nd term) +Exponent on (1 − 𝐹) (2nd term) +Pressure Exponent (2nd term) +FMXGR +Maximum 𝐹 for 1st term +FMNGR +Minimum 𝐹 for 2nd term +Remarks: +A deflagration (burn rate) reactive flow model requires an unreacted solid equation of +state, a reaction product equation of state, a reaction rate law and a mixture rule for the +two (or more) species. The mixture rule for the standard ignition and growth model +[Lee and Tarver 1980] assumes that both pressures and temperatures are completely +equilibrated as the reaction proceeds. However, the mixture rule can be modified to +allow no thermal conduction or partial heating of the solid by the reaction product +gases. For this relatively slow process of airbag propellant burn, the thermal and +pressure equilibrium assumptions are valid. The equations of state currently used in +the burn model are the JWL, Gruneisen, the van der Waals co-volume, and the perfect +gas law, but other equations of state can be easily implemented. In this propellant burn, +the gaseous nitrogen produced by the burning sodium azide obeys the perfect gas law +as it fills the airbag but may have to be modeled as a van der Waal’s gas at the high +pressures and temperatures produced in the propellant chamber. The chemical reaction +rate law is pressure, particle geometry and surface area dependent, as are most high- +pressure burn processes. When the temperature profile of the reacting system is well +known, temperature dependent Arrhenius chemical kinetics can be used. +Since the airbag propellant composition and performance data are company private +information, it is very difficult to obtain the required information for burn rate +modeling. However, Imperial Chemical Industries (ICI) Corporation supplied pressure +exponent, particle geometry, packing density, heat of reaction, and atmospheric +pressure burn rate data which allowed us to develop the numerical model presented +here for their NaN3 + Fe2O3 driver airbag propellant. The deflagration model, its +implementation, and the results for the ICI propellant are presented in [Hallquist, et.al., +1990]. +The unreacted propellant and the reaction product equations of state are both of the +form: +𝑝 = 𝐴𝑒−𝑅1𝑉 + 𝐵𝑒−𝑅2𝑉 + +𝜔𝐶𝑣𝑇 +𝑉 − 𝑑 +where 𝑝 is pressure (in Mbars), 𝑉 is the relative specific volume (inverse of relative +density), 𝜔 is the Gruneisen coefficient, 𝐶𝑣 is heat capacity (in Mbars -cc/cc°K), 𝑇 is +temperature in °K, 𝑑 is the co-volume, and 𝐴, 𝐵, 𝑅1 and 𝑅2 are constants. Setting +𝐴 = 𝐵 = 0 yields the van der Waal’s co-volume equation of state. The JWL equation of +state is generally useful at pressures above several kilobars, while the van der Waal’s is +useful at pressures below that range and above the range for which the perfect gas law +holds. Additionally, setting 𝐴 = 𝐵 = 𝑑 = 0 yields the perfect gas law. If accurate values +of 𝜔 and 𝐶𝑣 plus the correct distribution between “cold” compression and internal +energies are used, the calculated temperatures are very reasonable and thus can be used +to check propellant performance. +The reaction rate used for the propellant deflagration process is of the form: +∂𝐹 +∂𝑡 += 𝑍(1 − 𝐹)𝑦𝐹𝑥𝑝𝑤 +⏟⏟⏟⏟⏟⏟⏟ +0<𝐹<𝐹limit1 ++ 𝑉(1 − 𝐹)𝑢𝐹𝑟𝑝𝑠 +⏟⏟⏟⏟⏟⏟⏟ +𝐹limit2<𝐹<1 +where 𝐹 is the fraction reacted (𝐹 = 0 implies no reaction, 𝐹 = 1 is complete reaction), 𝑡 +is time, and 𝑝 is pressure (in Mbars), 𝑟, 𝑠, 𝑢, 𝑤, 𝑥, 𝑦, 𝐹limit1 and 𝐹limit2 are constants used +to describe the pressure dependence and surface area dependence of the reaction rates. +Two (or more) pressure dependant reaction rates are included in case the propellant is a +mixture or exhibited a sharp change in reaction rate at some pressure or temperature. +Burning surface area dependencies can be approximated using the (1 − 𝐹)𝑦𝐹𝑥 terms. +Other forms of the reaction rate law, such as Arrhenius temperature dependent 𝑒−𝐸 𝑅𝑇⁄ +type rates, can be used, but these require very accurate temperatures calculations. +Although the theoretical justification of pressure dependent burn rates at kilobar type +pressures is not complete, a vast amount of experimental burn rate versus pressure data +does demonstrate this effect and hydrodynamic calculations using pressure dependent +burn accurately simulate such experiments. +The deflagration reactive flow model is activated by any pressure or particle velocity +increase on one or more zone boundaries in the reactive material. Such an increase +creates pressure in those zones and the decomposition begins. If the pressure is +relieved, the reaction rate decreases and can go to zero. This feature is important for +short duration, partial decomposition reactions. If the pressure is maintained, the +fraction reacted eventually reaches one and the material is completely converted to +product molecules. The deflagration front rates of advance through the propellant +calculated by this model for several propellants are quite close to the experimentally +observed burn rate versus pressure curves. +To obtain good agreement with experimental deflagration data, the model requires an +accurate description of the unreacted propellant equation of state, either an analytical fit +to experimental compression data or an estimated fit based on previous experience with +similar materials. This is also true for the reaction products equation of state. The more +experimental burn rate, pressure production and energy delivery data available, the +better the form and constants in the reaction rate equation can be determined. +Therefore, the equations used in the burn subroutine for the pressure in the unreacted +propellant +𝑃𝑢 = R1 × 𝑒−R5⋅𝑉𝑢 + R2 × 𝑒−R6⋅𝑉𝑢 + +R3 × 𝑇𝑢 +𝑉𝑢 − FRER +where 𝑉𝑢 and 𝑇𝑢 are the relative volume and temperature respectively of the unreacted +propellant. The relative density is obviously the inverse of the relative volume. The +pressure 𝑃𝑝 in the reaction products is given by: +𝑃𝑝 = A× 𝑒−XP1×𝑉𝑝 + B × 𝑒−XP2×𝑉𝑝 + +G×𝑇𝑝 +𝑉𝑝 − CCRIT +As the reaction proceeds, the unreacted and product pressures and temperatures are +assumed to be equilibrated (𝑇𝑢 = 𝑇𝑝 = 𝑇, 𝑃 = 𝑃𝑢 = 𝑃𝑝) and the relative volumes are +additive: +𝑉 = (1 − 𝐹)𝑉𝑢 + 𝐹𝑉𝑝 +where 𝑉 is the total relative volume. Other mixture assumptions can and have been +used in different versions of DYNA2D/3D. The reaction rate law has the form: +𝜕𝐹 +𝜕𝑡 += GROW1 × (𝑃 + FREQ)EM(𝐹 + FMXIG)AR1(1 − 𝐹 + FMIXG)ES1 ++ GROW2 × (𝑃 + FREQ)EN(𝐹 + FMIXG)AR2(1 − 𝐹 + FMIXG)ES2 +If 𝐹 exceeds FMXGR, the GROW1 term is set equal to zero, and, if 𝐹 is less than +FMNGR, the GROW2 term is zero. Thus, two separate (or overlapping) burn rates can +be used to describe the rate at which the propellant decomposes. +This equation of state subroutine is used together with a material model to describe the +propellant. In the airbag propellant case, a null material model (type #10) can be used. +Material type #10 is usually used for a solid propellant or explosive when the shear +modulus and yield strength are defined. The propellant material is defined by the +material model and the unreacted equation of state until the reaction begins. The +calculated mixture states are used until the reaction is complete and then the reaction +product equation of state is used. The heat of reaction, ENQ, is assumed to be a +constant and the same at all values of 𝐹 but more complex energy release laws could be +implemented. +History variables 4 and 7 are temperature and burn fraction, respectively. See NEIPH +in *DATABASE_EXTENT_BINARY if these output variables are desired in the +databases for post-processing. +This is Equation of state Form 11. +*EOS + Card 1 +1 +2 +3 +4 +5 +Variable +EOSID +NLD +NCR +MU1 +MU2 +6 +IE0 +7 +EC0 +8 +Type +A8 +F +F +F +F +F +F +DESCRIPTION +Equation of state ID, a unique number or label not exceeding 8 +characters must be specified. +Virgin loading load curve ID +Completely crushed load curve ID +Excess Compression required before any pores can collapse +Excess Compression point where the Virgin Loading Curve and +the Completely Crushed Curve intersect +Initial Internal Energy +Initial Excess Compression + VARIABLE +EOSID +NLD +NCR +MU1 +MU2 +IE0 +EC0 +Remarks: +The pore collapse model described in the TENSOR manual [23] is no longer valid and +has been replaced by a much simpler method. This is due in part to the lack of +experimental data required for the more complex model. It is desired to have a close +approximation of the TENSOR model in the DYNA code to enable a quality link +between them. The TENSOR model defines two curves, the virgin loading curve and +the completely crushed curve as shown in Figure EOS11-1 also defines the excess +compression point required for pore collapse to begin, 𝜇1, and the excess compression +point required to completely crush the material, 𝜇2. From this data and the maximum +excess compression the material has attained, 𝑢max, the pressure for any excess +compression, 𝜇, can be determined. +1.0 +.8 +.6 +.4 +.2 +( +) +Virgin +loading +curve +Completely +crushed +curve +Partially +crushed +curve +.04 +.08 +.12 +.16 +.20 +Excess Compression +Figure EOS11-1. Pressure versus compaction curve +Unloading occurs along the virgin loading curve until the excess compression surpasses +𝜇1. After that, the unloading follows a path between the completely crushed curve and +the virgin loading curve. Reloading will follow this curve back up to the virgin loading +curve. Once the excess compression exceeds 𝜇2, then all unloading will follow the +completely crushed curve. +For unloading between 𝜇1 and a partially𝜇2 crushed curve is determined by the +relation: +where +𝑝pc(𝜇) = 𝑝cc [ +𝜇𝑎 +⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞⏞ +(1 + 𝜇𝐵)(1 + 𝜇) +− 1] +1 + 𝜇max +. +𝜇𝐵 = 𝑃cc +−1(𝑃max) +and the subscripts “pc” and “cc” refer to the partially crushed and completely crushed +states, respectively. This is more readily understood in terms of the relative volume, 𝑉. +𝑉 = +1 + 𝜇 +𝑃pc(𝑉) = 𝑃cc ( +𝑉𝐵 +𝑉min +𝑉) +This representation suggests that for a fixed +𝑉min = +𝜇max + 1 +the partially crushed curve will separate linearly from the completely crushed curve as +𝑉 increases to account for pore recovery in the material. +The bulk modulus 𝐾 is determined to be the slope of the current curve times one plus +the excess compression +𝐾 = +∂𝑃 +∂𝜇 +(1 + 𝜇) +The slope ∂𝑃 +∂𝜇 for the partially crushed curve is obtained by differentiation as: +𝜕𝑝pc +𝜕𝜇 += +𝜕𝑝cc +𝜕𝑥 +∣ +𝑥= +(1+𝜇𝑏)(1+𝜇) +1+𝜇max +−1 +( +1 + 𝜇𝑏 +1 + 𝜇max +) +Simplifying, +where +𝐾 = +∂𝑃cc +∂𝜇𝑎 +∣ +μa +(1 + 𝜇𝑎) +𝜇𝑎 = +(1 + 𝜇𝐵)(1 + 𝜇) +(1 + 𝜇max) +− 1. +The bulk sound speed is determined from the slope of the completely crushed curve at +the current pressure to avoid instabilities in the time step. +The virgin loading and completely crushed curves are modeled with monotonic cubic- +splines. An optimized vector interpolation scheme is then used to evaluate the cubic- +splines. The bulk modulus and sound speed are derived from a linear interpolation on +the derivatives of the cubic-splines. +*EOS_IDEAL_GAS +Purpose: This is equation of state form 12 for modeling ideal gas. It is an alternate +approach to using *EOS_LINEAR_POLYNOMIAL with C4 = C5 = (𝛾 − 1) to model +ideal gas. This has a slightly improved energy accounting algorithm. + Card 1 +1 +2 +3 +Variable +EOSID +CV0 +CP0 +4 +CL +F +4 +5 +CQ +F +5 +6 +T0 +F +6 +7 +V0 +F +7 +8 +VCO +F +8 +F +2 +F +3 +Type +A8 + Card 2 +1 +Variable +ADIAB +Type +F + VARIABLE +EOSID +CV0 +CP0 +CL +CQ +T0 +V0 +DESCRIPTION +Equation of state ID, a unique number or label not exceeding 8 +characters must be specified. +Nominal constant-volume specific heat coefficient (at STP) +Nominal constant-pressure specific heat coefficient (at STP) +Linear coefficient for the variations of 𝐶𝑣 and 𝐶𝑝versus 𝑇. +Quadratic coefficient for the variations of 𝐶𝑣 and 𝐶𝑝 versus 𝑇. +Initial temperature +Initial relative volume +VCO +Van der Waals covolume +ADIAB +Adiabatic flag: +EQ.0.0: off +EQ.1.0: on; ideal gas follows adiabatic law +1. The pressure in the ideal gas law is defined as +*EOS +𝑝 = 𝜌(𝐶𝑝 − 𝐶𝑣)𝑇 +𝐶𝑝 = 𝐶𝑝0 + 𝐶𝐿𝑇 + 𝐶𝑄𝑇2 +𝐶𝑣 = 𝐶𝑣0 + 𝐶𝐿𝑇 + 𝐶𝑄𝑇2 +where 𝐶𝑝 and 𝐶𝑣 are the specific heat capacities at constant pressure and at +constant volume, respectively. 𝜌 is the density. The relative volume is defined +as +𝜐𝑟 = +𝑉0 += +) +(𝑉 𝑀⁄ +) +(𝑉0 𝑀⁄ += +𝜐0 += +𝜌0 +where 𝜌0 is a nominal or reference density defined in the *MAT_NULL card. +The initial pressure can then be manually computed as +𝑃|𝑡=0 = 𝜌∣𝑡=0(𝐶𝑃 − 𝐶𝑉)𝑇|𝑡=0 +𝜌∣𝑡=0 = { +𝑃|𝑡=0 = { +𝜌0 +𝜐𝑟|𝑡=0 +𝜌0 +𝜐𝑟|𝑡=0 +} +} (𝐶𝑃 − 𝐶𝑉)𝑇|𝑡=0 +The initial relative volume, 𝜐𝑟|𝑡=0 (V0), initial temperature, 𝑇|𝑡=0(T0), and heat +capacity information are defined in the *EOS_IDEAL_GAS input. Note that the +“reference” density is typically a density at a non-stressed or nominal stress +state. The initial pressure should always be checked manually against simula- +tion result. +2. With adiabatic flag on, the adiabatic state is conserved, but extact internal +energy conservation is scarified. +3. The ideal gas model is good for low density gas only. Deviation from the ideal +gas behavior may be indicated by the compressibility factor defined as +𝑍 = +𝑃𝜐 +𝑅𝑇 +When 𝑍 deviates from 1, the gas behavior deviates from ideal. +4. V0 and T0 defined in this card must be the same as the time-zero ordinates for +the 2 load curves defined in the *BOUNDARY_AMBIENT_EOS card, if it is +used. This is so that they both would consistently define the same initial state +for a material. +*EOS_JWLB +This is Equation of state Form 14. The JWLB (Jones-Wilkens-Lee-Baker) equation of +state, developed by Baker [1991] and further described by Baker and Orosz [1991], +describes the high pressure regime produced by overdriven detonations while retaining +the low pressure expansion behavior required for standard acceleration modeling. The +derived form of the equation of state is based on the JWL form due to its computational +robustness and asymptotic approach to an ideal gas at high expansions. Additional +exponential terms and a variable Gruneisen parameter have been added to adequately +describe the high-pressure region above the Chapman-Jouguet state. + Card 1 +1 +Variable +EOSID +Type +A8 + Card 2 +Variable +1 +R1 +Type +F + Card 3 +1 +2 +A1 +F +2 +R2 +F +2 +3 +A2 +F +3 +R3 +F +3 +4 +A3 +F +4 +R4 +F +4 +5 +A4 +F +5 +R5 +F +5 +Variable +AL1 +AL2 +AL3 +AL4 +AL5 +Type +F + Card 4 +1 +F +2 +F +3 +F +4 +F +5 +Variable +BL1 +BL2 +BL3 +BL4 +BL5 +Type +F +F +F +F +F +6 +A5 +F +6 +7 +8 +7 +8 +6 +7 +8 +6 +7 +Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RL1 +RL2 +RL3 +RL4 +RL5 +Type +F + Card 6 +Variable +Type +1 +C +I +F +2 +OMEGA +F +F +3 +E +F +F +4 +V0 +F +F +5 +6 +7 +8 + VARIABLE +EOSID +DESCRIPTION +Equation of state ID, a unique number or label not +exceeding 8 characters must be specified. +Ai, Ri, Ali, BLi, C, OMEGA +Equation of state coefficients 𝐴𝑖, 𝑅𝑖, 𝐴𝜆𝑖, 𝐵𝜆𝑖, 𝑅𝜆𝑖, 𝐶, +𝜔 respectively. See below. +C +Equation of state coefficient, see below. +OMEGA +Equation of state coefficient, see below. +E +V0 +Energy density per unit initial volume +Initial relative volume. +Remarks: +The JWLB equation-of-state defines the pressure as +𝑝 = ∑ 𝐴𝑖 +𝑖=1 +(1 − +𝑅𝑖𝑉 +) 𝑒−𝑅𝑖𝑉 + +𝜆𝐸 ++ 𝐶 (1 − +) 𝑉−(𝜔+1) +𝜆 = ∑(𝐴𝜆𝑖𝑉 + 𝐵𝜆𝑖)𝑒−𝑅𝜆𝑖𝑉 + 𝜔 +𝑖=1 +where V is the relative volume, E is the energy per unit initial volume, and 𝐴𝑖, 𝑅𝑖, 𝐴𝜆𝑖, +𝐵𝜆𝑖, 𝑅𝜆𝑖, 𝐶, and 𝜔 are input constants defined above. +JWLB input constants for some common explosives as found in Baker and Stiel [1997] +are given in the following table. +E0 (Mbar) +DCJ (cm/μs) +PCJ (Mbar) +A1 (Mbar) +A2 (Mbar) +A3 (Mbar) +A4 (Mbar) +R1 +R2 +R3 +R4 +C (Mbar) +ω +Aλ1 +Bλ1 +Rλ1 +Aλ2 +Bλ2 +Rλ2 +TATB +1.800 +.07040 +.76794 +.23740 +550.06 +22.051 +.42788 +.28094 +16.688 +6.8050 +2.0737 +2.9754 +.00776 +.27952 +1423.9 +14387. +19.780 +5.0364 +-2.6332 +1.7062 +LX-14 +1.821 +.10205 +.86619 +.31717 +549.60 +64.066 +2.0972 +.88940 +34.636 +8.2176 +20.401 +2.0616 +.01251 +.38375 +18307. +1390.1 +19.309 +4.4882 +-2.6181 +1.5076 +PETN +1.765 +.10910 +.83041 +.29076 +521.96 +71.104 +4.4774 +.97725 +44.169 +8.7877 +25.072 +2.2251 +.01570 +.32357 +12.257 +52.404 +43.932 +8.6351 +-4.9176 +2.1303 +*EOS_JWLB +Octol 70/30 +1.803 +.09590 +.82994 +.29369 +526.83 +60.579 +.91248 +.00159 +52.106 +8.3998 +2.1339 +.18592 +.00968 +.39023 +.011929 +18466. +20.029 +5.4192 +-3.2394 +1.5868 +TNT +1.631 +.06656 +.67174 +.18503 +490.07 +56.868 +.82426 +.00093 +40.713 +9.6754 +2.4350 +.15564 +.00710 +.30270 +.00000 +1098.0 +15.614 +11.468 +-6.5011 +2.1593 +*EOS +This is Equation of state Form 15. This EOS works with solid elements and the thick +shell using selective reduced 2 × 2 integration (ELFORM = 2 on SECTION_TSHELL) to +model the response of gaskets. For the thick shell only, it is completely decoupled from +the shell material, i.e., in the local coordinate system of the shell, this model defines the +normal stress, 𝜎𝑧𝑧, and does not change any of the other stress components. The model +is a reduction of the *MAT_GENERAL_NONLINEAR_6DOF_DISCRETE_BEAM. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EOSID +LCID1 +LCID2 +LCID3 +LCID4 +Type +A8 + Card 2 +1 +Variable +UNLOAD +Type +F +I +2 +K +F +I +3 +I +4 +I +5 +6 +7 +8 +DMPF +TFS +CFS +LOFFSET +IVS +F +F +F +F +F + VARIABLE +DESCRIPTION +EOSID +LCID1 +LCID2 +LCID3 +LCID4 +Equation of state ID, a unique number or label not exceeding 8 +characters must be specified. +Load curve for loading. +Load curve for unloading. +Load curve for damping as a function of volumetric strain rate. +Load curve for scaling the damping as a function of the +volumetric strain. +*EOS +Unload = 0 +Loading-unloading +curve +Unload = 2 +Unloading +curve +*EOS_GASKET +Unloading +curve +ρ∕ρ +μ = +0 − 1 +Unload = 1 +Unload = 3 +ρ∕ρ +μ = +0 − 1 +ρ∕ρ +μ = +0 − 1 +umin +× OFFSET +umin +Quadratic +unloading +ρ∕ρ +μ = +0 − 1 +Figure EOS15-1. Load and unloading behavior. + VARIABLE +DESCRIPTION +UNLOAD +Unloading option : +EQ.0.0: Loading and unloading follow loading curve +EQ.1.0: Loading follows loading curve, unloading follows +unloading curve. The unloading curve ID if undefined +is taken as the loading curve. +EQ.2.0: Loading follows loading curve, unloading follows +unloading stiffness, K, to the unloading curve. The +loading and unloading curves may only intersect at the +origin of the axes. +EQ.3.0: Quadratic unloading from peak displacement value to +DESCRIPTION +a permanent offset. +K +Unloading stiffness, for UNLOAD = 2 only. +*EOS +DMPF +TFS +CFS +OFFSET +Damping factor for stability. Values in the neighborhood of unity +are recommended. The damping factor is properly scaled to +eliminate time step size dependency. +Tensile failure strain. +Compressive failure strain. +Offset factor between 0 and 1.0 to determine permanent set upon + The permanent sets in +unloading if the UNLOAD = 3.0. +compression and tension are equal to the product of this offset +value and the maximum compressive and tensile displacements, +respectively. +IVS +Initial volume strain. +*EOS_MIE_GRUNEISEN +This is Equation of state Form 16, a Mie-Gruneisen form with a 𝑝 − 𝛼 compaction +model. + Card 1 +1 +2 +Variable +EOSID +GAMMA +Type +A8 +F +3 +A1 +F +4 +A2 +F +5 +A3 +F +6 +7 +PEL +PCO +F +F +8 +N +F +Default +none +none +none +none +none +none +none +none +4 +5 +6 +7 +8 + Card 2 +1 +Variable +ALPHA0 +Type +F +2 +E0 +F +3 +V0 +F +Default +none +none +none + VARIABLE +EOSID +DESCRIPTION +Equation of state identification. A unique number or label not +exceeding 8 characters must be specified. +GAMMA +Gruneisen gamma. +Ai +PEL +PCO +N +Hugoniot polynomial coefficient +Crush pressure +Compaction pressure +Porosity exponent +ALPHA0 +Initial porosity +E0 +V0 +Initial internal energy +Initial relative volume +*EOS +The equation of state is a Mie-Gruneisen form with a polynomial Hugoniot curve and a +𝑝 − 𝛼 compaction model. First, we define a history variable representing the porosity 𝛼 +that is initialised to 𝛼0 > 1. The evolution of this variable is given as +𝛼(𝑡) = max +⎜⎛1 + (𝛼0 − 1) [ +⎝ +where 𝑝(𝑡) indicates the pressure at time t. For later use, we define the cap pressure as +⎡𝛼0, min𝑠≤𝑡 +⎢ +⎣ +1, min +⎟⎞ +⎠ +𝑝comp − 𝑝(𝑠) +] +𝑝comp − 𝑝𝑒𝑙 +}⎫ +⎤ +⎥ +⎭}⎬ +⎦ +{⎧ +⎩{⎨ +𝑝𝑐 = 𝑝comp − (𝑝comp − 𝑝𝑒𝑙) [ +1/𝑁 +𝛼 − 1 +𝛼0 − 1 +] +The remainder of the EOS model is given by the equations +together with +𝑝(𝜌, 𝑒) = Γ𝛼𝜌𝑒 + 𝑝𝐻(𝜂) [1 − +Γ𝜂] +𝑝𝐻(𝜂) = 𝐴1𝜂 + 𝐴2𝜂2 + 𝐴3𝜂3 +𝜂(𝜌) = +𝛼𝜌 +𝛼0𝜌0 +− 1. +*EOS_GRUNEISEN +This is Equation of state Form 19. This EOS works with SPH elements to model the +response of fluids. + Card 1 +1 +2 +Variable +EOSID +GAMMA +Type +A8 +F +3 +K0 +F +4 +V0 +F +5 +6 +7 +8 + VARIABLE +EOSID +DESCRIPTION +Equation of state ID, a unique number or label not exceeding 8 +characters must be specified. +GAMMA, K0 +Constants in the equation of state. +V0 +Initial relative volume. +Remarks: +The Murnaghan equation of state defines pressure as +𝑝 = 𝑘0 [( +𝜌0 +) +− 1]. +*EOS +These are equations of state 21-30. The user can supply his own subroutines. See also +Appendix B. The keyword input has to be used for the user interface with data. + Card 1 +1 +2 +3 +4 +5 +Variable +EOSID +EOST +LMC +NHV +IVECT +Type +A8 +I +I +I +I +Define LMC material parameters using 8 parameters per card. + Card 2 +Variable +1 +P1 +Type +F +2 +P2 +F +3 +P3 +F +4 +P4 +F +5 +P5 +F +6 +EO +F +6 +P6 +F +7 +VO +F +7 +P7 +F +8 +BULK +F +8 +P8 +F + VARIABLE +EOSID +EOST +LMC +DESCRIPTION +Equation of state ID, a unique number or label not exceeding 8 +characters must be specified. +User equation of state type (21-30 inclusive). A number between +21 and 30 has to be chosen. +Length of material constant array which is equal to the number of +material constants to be input. (LMC ≤ 48) +NHV +Number of history variables to be stored, see Appendix B. +IVECT +EO +V0 +BULK +Vectorization flag (on = 1). A vectorized user subroutine must be +supplied. +Initial internal energy. +Initial relative volume. +Bulk modulus. This value is used in the calculation of the contact +surface stiffness. +Pi +Material parameters 𝑖 = 1, … ,LMC. +*MAT +LS-DYNA has historically referenced each material model by a number. As shown +below, a three digit numerical designation can still be used, e.g., *MAT_001, and is +equivalent to a corresponding descriptive designation, e.g., *MAT_ELASTIC. The two +equivalent commands for each material model, one numerical and the other descriptive, +are listed below. The numbers in square brackets identify the element +formulations for which the material model is implemented. The number in the curly +brackets, {n}, indicates the default number of history variables per element integration +point that are stored in addition to the 7 history variables which are stored by default. +Just as an example, for the type 16 fully integrated shell elements with 2 integration +points through the thickness, the total number of history variables is 8 × (𝑛 + 7). For +the Belytschko-Tsay type 2 element the number is 2 × (𝑛 + 7). +The meaning associated with particular extra history variables for a subset of material +models and equations of state are tabulated at http://www.dynasupport.com/howtos- +/material/history-variables. +An additional option TITLE may be appended to a *MAT keyword in which case an +additional line is read in 80a format which can be used to describe the material. At +present, LS-DYNA does not make use of the title. Inclusion of titles simply gives +greater clarity to input decks. +Key to numbers in square brackets +0 +13,14,15) +1H +1B +1I +1T +1D +1SW +2 +3a +3c +4 +5 +6 +7 +8A +- +- +- +- +- +- +- +- +- +- +- +- +- +- +- +Solids (and 2D continuum elements, i.e., shell formulations +Hughes-Liu beam +Belytschko resultant beam +Belytschko integrated solid and tubular beams +Truss +Discrete beam +Spotweld beam +Shells +Thick shell formulations 1,2,6 +Thick shell formulations 3,5,7 +Special airbag element +SPH element +Acoustic solid +Cohesive solid +Multi-material ALE solid (validated) +8B +9 +- +- +Multi-material ALE solid (implemented but not validated1) +Membrane element +*MAT_ADD_COHESIVE2 [7] {see associated material model} +*MAT_ADD_EROSION2 +*MAT_ADD_FATIGUE +*MAT_ADD_GENERALIZED_DAMAGE2 [2] +*MAT_ADD_PERMEABILTY +*MAT_ADD_PORE_AIR +*MAT_ADD_THERMAL_EXPANSION2 +*MAT_NONLOCAL2 +*MAT_ELASTIC [0,1H,1B,1I,1T,2,3a,3c,5,8A] {0} +*MAT_{OPTION}TROPIC_ELASTIC [0,2,3a,3c] {15} +*MAT_PLASTIC_KINEMATIC [0,1H,1I,1T,2,3a,3c,5,8A] {5} +*MAT_ELASTIC_PLASTIC_THERMAL [0,1H,1T,2,3a,3c,5,8B] {3} +*MAT_SOIL_AND_FOAM [0,5,3c,8A] {0} +*MAT_VISCOELASTIC [0,1H,2,3a,3c,5,8B] {19} +*MAT_BLATZ-KO_RUBBER [0,2,3ac,8B] {9} +*MAT_HIGH_EXPLOSIVE_BURN [0,5,3c,8A] {4} +*MAT_NULL [0,1,2,3c,5,8A] {3} +*MAT_ELASTIC_PLASTIC_HYDRO_{OPTION} [0,3c,5,8B] {4} +*MAT_STEINBERG [0,3c,5,8B] {5} +*MAT_001: +*MAT_001_FLUID: *MAT_ELASTIC_FLUID [0,8A] {0} +*MAT_002: +*MAT_003: +*MAT_004: +*MAT_005: +*MAT_006: +*MAT_007: +*MAT_008: +*MAT_009: +*MAT_010: +*MAT_011: +*MAT_011_LUND: *MAT_STEINBERG_LUND [0,3c,5,8B] {5} +*MAT_012: +*MAT_013: +*MAT_014: +*MAT_015: +*MAT_016: +*MAT_017: +*MAT_018: +*MAT_019: +*MAT_020: +*MAT_021: +*MAT_022: +*MAT_023: +*MAT_024: +*MAT_025: +*MAT_026: +*MAT_027: +*MAT_028: +*MAT_029: +*MAT_030: +*MAT_ISOTROPIC_ELASTIC_PLASTIC [0,2,3a,3c,5,8B] {0} +*MAT_ISOTROPIC_ELASTIC_FAILURE [0,3c,5,8B] {1} +*MAT_SOIL_AND_FOAM_FAILURE [0,3c,5,8B] {1} +*MAT_JOHNSON_COOK [0,2,3a,3c,5,8A] {6} +*MAT_PSEUDO_TENSOR [0,3c,5,8B] {6} +*MAT_ORIENTED_CRACK [0,3c] {14} +*MAT_POWER_LAW_PLASTICITY [0,1H,2,3a,3c,5,8B] {0} +*MAT_STRAIN_RATE_DEPENDENT_PLASTICITY [0,2,3a,3c,5,8B] {6} +*MAT_RIGID [0,1H,1B,1T,2,3a] {0} +*MAT_ORTHOTROPIC_THERMAL [0,2,3ac] {29} +*MAT_COMPOSITE_DAMAGE [0,2,3a,3c,5] {12} +*MAT_TEMPERATURE_DEPENDENT_ORTHOTROPIC [0,2,3ac] {19} +*MAT_PIECEWISE_LINEAR_PLASTICITY [0,1H,2,3a,3c,5,8A] {5} +*MAT_GEOLOGIC_CAP_MODEL [0,3c,5] {12} +*MAT_HONEYCOMB [0,3c] {20} +*MAT_MOONEY-RIVLIN_RUBBER [0,1T,2,3c,8B] {9} +*MAT_RESULTANT_PLASTICITY [1B,2] {5} +*MAT_FORCE_LIMITED [1B] {30} +*MAT_SHAPE_MEMORY [0,1H,2,3ac,5] {23} +1 Error associated with advection inherently leads to state variables that may be inconsistent with +nonlinear constitutive routines and thus may lead to nonphysical results, nonconservation of energy, and +even numerical instability in some cases. Caution is advised, particularly when using the 2nd tier of +material models implemented for ALE multi-material solids (designated by [8B]) which are largely +untested as ALE materials. +2 These commands do not, by themselves, define a material model but rather can be used in certain cases +to supplement material models +*MAT_FRAZER_NASH_RUBBER_MODEL [0,3c,8B] {9} +*MAT_031: +*MAT_LAMINATED_GLASS [2,3a] {0} +*MAT_032: +*MAT_BARLAT_ANISOTROPIC_PLASTICITY [0,2,3a,3c] {9} +*MAT_033: +*MAT_BARLAT_YLD96 [2,3a] {9} +*MAT_033_96: +*MAT_FABRIC [4] {17} +*MAT_034: +*MAT_PLASTIC_GREEN-NAGHDI_RATE [0,3c,5,8B] {22} +*MAT_035: +*MAT_3-PARAMETER_BARLAT [2,3a] {7} +*MAT_036: +*MAT_TRANSVERSELY_ANISOTROPIC_ELASTIC_PLASTIC [2,3a] {9} +*MAT_037: +*MAT_BLATZ-KO_FOAM [0,2,3c,8B] {9} +*MAT_038: +*MAT_FLD_TRANSVERSELY_ANISOTROPIC [2,3a] {6} +*MAT_039: +*MAT_NONLINEAR_ORTHOTROPIC [0,2,3c] {17} +*MAT_040: +*MAT_USER_DEFINED_MATERIAL_MODELS [0,1H,1T,1D,2,3a,3c,5,8B] {0} +*MAT_041-050: +*MAT_BAMMAN [0,2,3a,3c,5,8B] {8} +*MAT_051: +*MAT_BAMMAN_DAMAGE [0,2,3a,3c,5,8B] {10} +*MAT_052: +*MAT_CLOSED_CELL_FOAM [0,3c,8B] {0} +*MAT_053: +*MAT_ENHANCED_COMPOSITE_DAMAGE [0,2,3c] {20} +*MAT_054-055: +*MAT_LOW_DENSITY_FOAM [0,3c,5,8B] {26} +*MAT_057: +*MAT_LAMINATED_COMPOSITE_FABRIC [2,3a] {15} +*MAT_058: +*MAT_COMPOSITE_FAILURE_{OPTION}_MODEL [0,2,3c,5] {22} +*MAT_059: +*MAT_ELASTIC_WITH_VISCOSITY [0,2,3a,3c,5,8B] {8} +*MAT_060: +*MAT_ELASTIC_WITH_VISCOSITY_CURVE [0,2,3a,3c,5,8B] {8} +*MAT_060C: +*MAT_KELVIN-MAXWELL_VISCOELASTIC [0,3c,5,8B] {14} +*MAT_061: +*MAT_VISCOUS_FOAM [0,3c,8B] {7} +*MAT_062: +*MAT_CRUSHABLE_FOAM [0,3c,5,8B] {8} +*MAT_063: +*MAT_RATE_SENSITIVE_POWERLAW_PLASTICITY [0,2,3a,3c,5,8B] {30} +*MAT_064: +*MAT_MODIFIED_ZERILLI_ARMSTRONG [0,2,3a,3c,5,8B] {6} +*MAT_065: +*MAT_LINEAR_ELASTIC_DISCRETE_BEAM [1D] {8} +*MAT_066: +*MAT_NONLINEAR_ELASTIC_DISCRETE_BEAM [1D] {14} +*MAT_067: +*MAT_NONLINEAR_PLASTIC_DISCRETE_BEAM [1D] {25} +*MAT_068: +*MAT_SID_DAMPER_DISCRETE_BEAM [1D] {13} +*MAT_069: +*MAT_HYDRAULIC_GAS_DAMPER_DISCRETE_BEAM [1D] {8} +*MAT_070: +*MAT_CABLE_DISCRETE_BEAM [1D] {8} +*MAT_071: +*MAT_CONCRETE_DAMAGE [0,3c,5,8B] {6} +*MAT_072: +*MAT_CONCRETE_DAMAGE_REL3 [0,3c,5] {6} +*MAT_072R3: +*MAT_LOW_DENSITY_VISCOUS_FOAM [0,3c,8B] {56} +*MAT_073: +*MAT_ELASTIC_SPRING_DISCRETE_BEAM [1D] {8} +*MAT_074: +*MAT_BILKHU/DUBOIS_FOAM [0,3c,5,8B] {8} +*MAT_075: +*MAT_GENERAL_VISCOELASTIC [0,2,3a,3c,5,8B] {53} +*MAT_076: +*MAT_HYPERELASTIC_RUBBER [0,2,3c,5,8B] {54} +*MAT_077_H: +*MAT_OGDEN_RUBBER [0,2,3c,8B] {54} +*MAT_077_O: +*MAT_SOIL_CONCRETE [0,3c,5,8B] {3} +*MAT_078: +*MAT_HYSTERETIC_SOIL [0,3c,5,8B] {96} +*MAT_079: +*MAT_RAMBERG-OSGOOD [0,3c,8B] {18} +*MAT_080: +*MAT_081: +*MAT_PLASTICITY_WITH_DAMAGE [0,2,3a,3c] {5} +*MAT_082(_RCDC): *MAT_PLASTICITY_WITH_DAMAGE_ORTHO(_RCDC) [0,2,3a,3c] {22} +*MAT_083: +*MAT_084: +*MAT_086: +*MAT_087: +*MAT_088: +*MAT_089: +*MAT_090: +*MAT_091: +*MAT_092: +*MAT_FU_CHANG_FOAM [0,3c,5,8B] {54} +*MAT_WINFRITH_CONCRETE [0] {54} +*MAT_ORTHOTROPIC_VISCOELASTIC [2,3a] {17} +*MAT_CELLULAR_RUBBER [0,3c,5,8B] {19} +*MAT_MTS [0,2,3a,3c,5,8B] {5} +*MAT_PLASTICITY_POLYMER [0,2,3a,3c] {46} +*MAT_ACOUSTIC [6] {25} +*MAT_SOFT_TISSUE [0,2] {16} +*MAT_SOFT_TISSUE_VISCO [0,2] {58} +*MAT_094: +*MAT_095: +*MAT_096: +*MAT_097: +*MAT_098: +*MAT_099: +{22} +*EOS_USER_DEFINED +*MAT_ELASTIC_6DOF_SPRING_DISCRETE_BEAM [1D] {25} +*MAT_INELASTIC_SPRING_DISCRETE_BEAM [1D] {9} +*MAT_INELASTIC_6DOF_SPRING_DISCRETE_BEAM [1D] {25} +*MAT_BRITTLE_DAMAGE [0,8B] {51} +*MAT_GENERAL_JOINT_DISCRETE_BEAM [1D] {23} +*MAT_SIMPLIFIED_JOHNSON_COOK [0,1H,1B,1T,2,3a,3c] {6} +*MAT_SIMPLIFIED_JOHNSON_COOK_ORTHOTROPIC_DAMAGE +[0,2,3a,3c] +*MAT_100: +*MAT_100_DA: +*MAT_101: +*MAT_102(_T): +*MAT_103: +*MAT_103_P: +*MAT_104: +*MAT_105: +*MAT_106: +*MAT_107: +*MAT_108: +*MAT_110: +*MAT_111: +*MAT_112: +*MAT_113: +*MAT_114: +*MAT_115: +*MAT_115_O: +*MAT_116: +*MAT_117: +*MAT_118: +*MAT_119: +*MAT_120: +*MAT_120_JC: +*MAT_120_RCDC: +*MAT_121: +*MAT_122: +*MAT_122_3D: +*MAT_123: +*MAT_124: +*MAT_125: +*MAT_126: +*MAT_127: +*MAT_128: +*MAT_129: +*MAT_130: +*MAT_131: +*MAT_132: +*MAT_133: +*MAT_134: +*MAT_135: +*MAT_135_PLC: +*MAT_136: +*MAT_138: +*MAT_139: +*MAT_140: +*MAT_SPOTWELD_{OPTION} [0,1SW] {6} +*MAT_SPOTWELD_DAIMLERCHRYSLER [0] {6} +*MAT_GEPLASTIC_SRATE_2000a [2,3a] {15} +*MAT_INV_HYPERBOLIC_SIN(_THERMAL) [0,3c,8B] {15} +*MAT_ANISOTROPIC_VISCOPLASTIC [0,2,3a,3c,5] {20} +*MAT_ANISOTROPIC_PLASTIC [2,3a,3c] {20} +*MAT_DAMAGE_1 [0,2,3a,3c] {11} +*MAT_DAMAGE_2 [0,2,3a,3c] {7} +*MAT_ELASTIC_VISCOPLASTIC_THERMAL [0,2,3a,3c,5] {20} +*MAT_MODIFIED_JOHNSON_COOK [0,2,3a,3c,5,8B] {15} +*MAT_ORTHO_ELASTIC_PLASTIC [2,3a] {15} +*MAT_JOHNSON_HOLMQUIST_CERAMICS [0,3c,5] {15} +*MAT_JOHNSON_HOLMQUIST_CONCRETE [0,3c,5] {25} +*MAT_FINITE_ELASTIC_STRAIN_PLASTICITY [0,3c,5] {22} +*MAT_TRIP [2,3a] {5} +*MAT_LAYERED_LINEAR_PLASTICITY [2,3a] {13} +*MAT_UNIFIED_CREEP [0,2,3a,3c,5] {1} +*MAT_UNIFIED_CREEP_ORTHO [0,3c,5] {1} +*MAT_COMPOSITE_LAYUP [2] {30} +*MAT_COMPOSITE_MATRIX [2] {30} +*MAT_COMPOSITE_DIRECT [2] {10} +*MAT_GENERAL_NONLINEAR_6DOF_DISCRETE_BEAM [1D] {62} +*MAT_GURSON [0,2,3a,3c] {12} +*MAT_GURSON_JC [0,2] {12} +*MAT_GURSON_RCDC [0,2] {12} +*MAT_GENERAL_NONLINEAR_1DOF_DISCRETE_BEAM [1D] {20} +*MAT_HILL_3R [2,3a] {8} +*MAT_HILL_3R_3D [0] {28} +*MAT_MODIFIED_PIECEWISE_LINEAR_PLASTICITY [0,2,3a,3c,5] {11} +*MAT_PLASTICITY_COMPRESSION_TENSION [0,1H,2,3a,3c,5,8B] {7} +*MAT_KINEMATIC_HARDENING_TRANSVERSELY_ANISOTROPIC [0,2,3a,3c] {11} +*MAT_MODIFIED_HONEYCOMB [0,3c] {20} +*MAT_ARRUDA_BOYCE_RUBBER [0,3c,5] {49} +*MAT_HEART_TISSUE [0,3c] {15} +*MAT_LUNG_TISSUE [0,3c] {49} +*MAT_SPECIAL_ORTHOTROPIC [2] {35} +*MAT_ISOTROPIC_SMEARED_CRACK [0,5,8B] {15} +*MAT_ORTHOTROPIC_SMEARED_CRACK [0] {61} +*MAT_BARLAT_YLD2000 [2,3a] {9} +*MAT_VISCOELASTIC_FABRIC [9] +*MAT_WTM_STM [2,3a] {30} +*MAT_WTM_STM_PLC [2,3a] {30} +*MAT_CORUS_VEGTER [2,3a] {5} +*MAT_COHESIVE_MIXED_MODE [7] {0} +*MAT_MODIFIED_FORCE_LIMITED [1B] {35} +*MAT_VACUUM [0,8A] {0} +*MAT_141: +*MAT_142: +*MAT_143: +*MAT_144: +*MAT_145: +*MAT_146: +*MAT_147 +*MAT_147_N: +*MAT_148: +*MAT_151: +*MAT_153: +*MAT_154: +*MAT_155: +*MAT_156: +*MAT_157: +*MAT_158: +*MAT_159: +*MAT_160: +*MAT_161: +*MAT_162: +*MAT_163 +*MAT_164: +*MAT_165: +*MAT_165B: +*MAT_166: +*MAT_167: +*MAT_168: +*MAT_169: +*MAT_170: +*MAT_171: +*MAT_172: +*MAT_173: +*MAT_174: +*MAT_175: +*MAT_176: +*MAT_177: +*MAT_178: +*MAT_179: +*MAT_181: +*MAT_183: +*MAT_184: +*MAT_185: +*MAT_186: +*MAT_187: +*MAT_188: +*MAT_189: +*MAT_190: +*MAT_191: +*MAT_192: +*MAT_193: +*MAT_194: +*MAT_195: +*MAT_196: +*MAT_197: +*MAT_RATE_SENSITIVE_POLYMER [0,3c,8B] {6} +*MAT_TRANSVERSELY_ISOTROPIC_CRUSHABLE_FOAM [0,3c] {12} +*MAT_WOOD_{OPTION} [0,3c,5] {37} +*MAT_PITZER_CRUSHABLE_FOAM [0,3c,8B] {7} +*MAT_SCHWER_MURRAY_CAP_MODEL [0,5] {50} +*MAT_1DOF_GENERALIZED_SPRING [1D] {1} +*MAT_FHWA_SOIL [0,3c,5,8B] {15} +*MAT_FHWA_SOIL_NEBRASKA [0,3c,5,8B] {15} +*MAT_GAS_MIXTURE [0,8A] {14} +*MAT_EMMI [0,3c,5,8B] {23} +*MAT_DAMAGE_3 [0,1H,2,3a,3c] +*MAT_DESHPANDE_FLECK_FOAM [0,3c,8B] {10} +*MAT_PLASTICITY_COMPRESSION_TENSION_EOS [0,3c,5,8B] {16} +*MAT_MUSCLE [1T] {0} +*MAT_ANISOTROPIC_ELASTIC_PLASTIC [0,2,3a] {5} +*MAT_RATE_SENSITIVE_COMPOSITE_FABRIC [2,3a] {54} +*MAT_CSCM_{OPTION} [0,3c,5] {22} +*MAT_ALE_INCOMPRESSIBLE +*MAT_COMPOSITE_MSC [0] {34} +*MAT_COMPOSITE_DMG_MSC [0] {40} +*MAT_MODIFIED_CRUSHABLE_FOAM [0,3c,8B] {10} +*MAT_BRAIN_LINEAR_VISCOELASTIC [0] {14} +*MAT_PLASTIC_NONLINEAR_KINEMATIC [0,2,3a,3c,8B] {8} +*MAT_PLASTIC_NONLINEAR_KINEMATIC_B [0,2] +*MAT_MOMENT_CURVATURE_BEAM [1B] {54} +*MAT_MCCORMICK [03c,,8B] {8} +*MAT_POLYMER [0,3c,8B] {60} +*MAT_ARUP_ADHESIVE [0] {30} +*MAT_RESULTANT_ANISOTROPIC [2,3a] {67} +*MAT_STEEL_CONCENTRIC_BRACE [1B] {35} +*MAT_CONCRETE_EC2 [1H,2,3a] {64} +*MAT_MOHR_COULOMB [0,5] {52} +*MAT_RC_BEAM [1H] {22} +*MAT_VISCOELASTIC_THERMAL [0,2,3a,3c,5,8B] {86} +*MAT_QUASILINEAR_VISCOELASTIC [0,2,3a,3c,5,8B] {81} +*MAT_HILL_FOAM [0,3c] {12} +*MAT_VISCOELASTIC_HILL_FOAM [0,3c] {92} +*MAT_LOW_DENSITY_SYNTHETIC_FOAM_{OPTION} [0,3c] {77} +*MAT_SIMPLIFIED_RUBBER/FOAM_{OPTION} [0,2,3c] {39} +*MAT_SIMPLIFIED_RUBBER_WITH_DAMAGE [0,2,3c] {44} +*MAT_COHESIVE_ELASTIC [7] {0} +*MAT_COHESIVE_TH [7] {0} +*MAT_COHESIVE_GENERAL [7] {6} +*MAT_SAMP-1 [0,2,3a,3c] {38} +*MAT_THERMO_ELASTO_VISCOPLASTIC_CREEP [0,2,3a,3c] {27} +*MAT_ANISOTROPIC_THERMOELASTIC [0,3c,8B] {21} +*MAT_FLD_3-PARAMETER_BARLAT [2,3a] {36} +*MAT_SEISMIC_BEAM [1B] {36} +*MAT_SOIL_BRICK [0,3c] {96} +*MAT_DRUCKER_PRAGER [0,3c] {24} +*MAT_RC_SHEAR_WALL [2,3a] {36} +*MAT_CONCRETE_BEAM [1H] {5} +*MAT_GENERAL_SPRING_DISCRETE_BEAM [1D] {25} +*MAT_SEISMIC_ISOLATOR [1D] {20} +*MAT_JOINTED_ROCK [0] {31} +*MAT_STEEL_EC3 [1H] {3} +*MAT_HYSTERETIC_REINFORCEMENT [1H,2] {64} +*MAT_BOLT_BEAM [1D] {16} +*MAT_SPR_JLR [1H] {60} +*MAT_DRY_FABRIC [9] +*MAT_4A_MICROMEC [0,2,3a,3c] +*MAT_ELASTIC_PHASE_CHANGE [0] +*MAT_OPTION_TROPIC_ELASTIC_PHASE_CHANGE [0] +*MAT_MOONEY-RIVLIN_RUBBER_PHASE_CHANGE [0] +*MAT_CODAM2 [0,2,3a,3c] +*MAT_RIGID_DISCRETE [0,2] +*MAT_ORTHOTROPIC_SIMPLIFIED_DAMAGE [0,3c,5] {17} +*MAT_TABULATED_JOHNSON_COOK [0,2,3a,3c,,5] {17} +*MAT_TABULATED_JOHNSON_COOK_GYS [0] {17} +*MAT_VISCOPLASTIC_MIXED_HARDENING [0,2,3a,3c,5] +*MAT_KINEMATIC_HARDENING_BARLAT89 [2,3a] +*MAT_PML_ELASTIC [0] {24} +*MAT_PML_ACOUSTIC [6] {35} +*MAT_BIOT_HYSTERETIC [0,2,3a] {30} +*MAT_CAZACU_BARLAT [2,3a] +*MAT_VISCOELASTIC_LOOSE_FABRIC [2,3a] +*MAT_MICROMECHANICS_DRY_FABRIC [2,3a] +*MAT_SCC_ON_RCC [2,3a] +*MAT_PML_HYSTERETIC [0] {54} +*MAT_PERT_PIECEWISE_LINEAR_PLASTICITY [0,1H,2,3,5,8A] +*MAT_COHESIVE_MIXED_MODE_ELASTOPLASTIC_RATE [7] {0} +*MAT_JOHNSON_HOLMQUIST_JH1 [0,3c,5] +*MAT_KINEMATIC_HARDENING_BARLAT2000 [2,3a] +*MAT_HILL_90 [2,3a] +*MAT_UHS_STEEL [0,2,3a,3c,5] {35} +*MAT_PML_{OPTION}TROPIC_ELASTIC [0] {30} +*MAT_PML_NULL [0] {27} +*MAT_PHS_BMW [2] {38} +*MAT_REINFORCED_THERMOPLASTIC [2] +*MAT_198: +*MAT_202: +*MAT_203: +*MAT_208: +*MAT_211: +*MAT_214: +*MAT_215: +*MAT_216: +*MAT_217: +*MAT_218: +*MAT_219: +*MAT_220: +*MAT_221: +*MAT_224: +*MAT_224_GYS: +*MAT_225: +*MAT_226: +*MAT_230: +*MAT_231: +*MAT_232: +*MAT_233: +*MAT_234: +*MAT_235: +*MAT_236: +*MAT_237: +*MAT_238: +*MAT_240: +*MAT_241: +*MAT_242: +*MAT_243: +*MAT_244: +*MAT_245: +*MAT_246: +*MAT_248: +*MAT_249: +*MAT_249_UDFIBER: *MAT_REINFORCED_THERMOPLASTIC_UDFIBER [2] +*MAT_251: +*MAT_252: +*MAT_254: +*MAT_255: +*MAT_256: +*MAT_260A: +*MAT_260B: +*MAT_261: +*MAT_262: +*MAT_264: +*MAT_266: +*MAT_267: +*MAT_269: +*MAT_270: +*MAT_271: +*MAT_272: +*MAT_273: +*MAT_274: +*MAT_TAILORED_PROPERTIES [2] {6} +*MAT_TOUGHENED_ADHESIVE_POLYMER [0,7] {10} +*MAT_GENERALIZED_PHASE_CHANGE [0,2] +*MAT_PIECEWISE_LINEAR_PLASTIC_THERMAL [0,2,3a,3c] +*MAT_AMORPHOUS_SOLIDS_FINITE_STRAIN [0] +*MAT_STOUGHTON_NON_ASSOCIATED_FLOW [0,2] +*MAT_MOHR_NON_ASSOCIATED_FLOW [0,2] +*MAT_LAMINATED_FRACTURE_DAIMLER_PINHO [0,2,3a,3c] +*MAT_LAMINATED_FRACTURE_DAIMLER_CAMANHO [0,2,3a,3c] +*MAT_TABULATED_JOHNSON_COOK_ORTHO_PLASTICITY [0] +*MAT_TISSUE_DISPERSED [0] +*MAT_EIGHT_CHAIN_RUBBER [0,5] +*MAT_BERGSTROM_BOYCE_RUBBER [0,5] +*MAT_CWM [0,2,5] +*MAT_POWDER [0,5] +*MAT_RHT [0,5] +*MAT_CONCRETE_DAMAGE_PLASTIC_MODEL [0] +*MAT_PAPER [0,2] +*MAT_275: +*MAT_276: +*MAT_277: +*MAT_278: +*MAT_279: +*MAT_280: +*MAT_293: +*MAT_SMOOTH_VISCOELASTIC_VISCOPLASTIC [0] +*MAT_CHRONOLOGICAL_VISCOELASTIC [2,3a,3c] +*MAT_ADHESIVE_CURING_VISCOELASTIC [0] +*MAT_CF_MICROMECHANICS [02] {3} +*MAT_COHESIVE_PAPER [7] +*MAT_GLASS [2] {32} +*MAT_COMPRF [2] {7} +For the discrete (type 6) beam elements, which are used to model complicated dampers +and multi-dimensional spring-damper combinations, the following material types are +available: +*MAT_066: +*MAT_067: +*MAT_068: +*MAT_069: +*MAT_070: +*MAT_071: +*MAT_074: +*MAT_093: +*MAT_094: +*MAT_095: +*MAT_119: +*MAT_121: +*MAT_146: +*MAT_196: +*MAT_197: +*MAT_208: +*MAT_LINEAR_ELASTIC_DISCRETE_BEAM [1D] +*MAT_NONLINEAR_ELASTIC_DISCRETE_BEAM [1D] +*MAT_NONLINEAR_PLASTIC_DISCRETE_BEAM [1D] +*MAT_SID_DAMPER_DISCRETE_BEAM [1D] +*MAT_HYDRAULIC_GAS_DAMPER_DISCRETE_BEAM [1D] +*MAT_CABLE_DISCRETE_BEAM [1D] +*MAT_ELASTIC_SPRING_DISCRETE_BEAM [1D] +*MAT_ELASTIC_6DOF_SPRING_DISCRETE_BEAM [1D] +*MAT_INELASTIC_SPRING_DISCRETE_BEAM [1D] +*MAT_INELASTIC_6DOF_SPRING_DISCRETE_BEAM [1D] +*MAT_GENERAL_NONLINEAR_6DOF_DISCRETE_BEAM [1D] +*MAT_GENERAL_NONLINEAR_1DOF_DISCRETE_BEAM [1D] +*MAT_1DOF_GENERALIZED_SPRING [1D] +*MAT_GENERAL_SPRING_DISCRETE_BEAM [1D] +*MAT_SEISMIC_ISOLATOR [1D] +*MAT_BOLT_BEAM [1D] +For the discrete springs and dampers the following material types are available +*MAT_S01: +*MAT_S02: +*MAT_S03: +*MAT_S04: +*MAT_S05: +*MAT_S06: +*MAT_S07: +*MAT_S08: +*MAT_S13: +*MAT_S14: +*MAT_S15: +*MAT_SPRING_ELASTIC +*MAT_DAMPER_VISCOUS +*MAT_SPRING_ELASTOPLASTIC +*MAT_SPRING_NONLINEAR_ELASTIC +*MAT_DAMPER_NONLINEAR_VISCOUS +*MAT_SPRING_GENERAL_NONLINEAR +*MAT_SPRING_MAXWELL +*MAT_SPRING_INELASTIC +*MAT_SPRING_TRILINEAR_DEGRADING +*MAT_SPRING_SQUAT_SHEARWALL +*MAT_SPRING_MUSCLE +For ALE solids the following material types are available: +*MAT_ALE_01: +*MAT_ALE_02: +*MAT_ALE_03: +*MAT_ALE_04: +*MAT_ALE_05: +*MAT_ALE_06: +*MAT_ALE_VACUUM +*MAT_ALE_GAS_MIXTURE +*MAT_ALE_VISCOUS +*MAT_ALE_MIXING_LENGTH +*MAT_ALE_INCOMPRESSIBLE +*MAT_ALE_HERSCHEL +(same as *MAT_140) +(same as *MAT_148) +(same as *MAT_009) +(same as *MAT_149) +(same as *MAT_160) +For SPH particles the following material type is available: +*MAT_SPH_01: +*MAT_SPH_VISCOUS +(same as *MAT_009) +For the seatbelts one material is available. +*MAT_B01: +*MAT_SEATBELT +For thermal materials in a coupled structural/thermal or thermal only analysis, six +materials are available. These materials are related to the structural material via the +*PART card. +*MAT_T01: +*MAT_T02: +*MAT_T03: +*MAT_T04: +*MAT_T05: +*MAT_T07: +*MAT_T08 +*MAT_T09 +*MAT_T10 +*MAT_T11-T15: +*MAT_THERMAL_ISOTROPIC +*MAT_THERMAL_ORTHOTROPIC +*MAT_THERMAL_ISOTROPIC_TD +*MAT_THERMAL_ORTHOTROPIC_TD +*MAT_THERMAL_DISCRETE_BEAM +*MAT_THERMAL_CWM +*MAT_THERMAL_ORTHOTROPIC_TD_LC +*MAT_THERMAL_ISOTROPIC_PHASE_CHANGE +*MAT_THERMAL_ISOTROPIC_TD_LC +*MAT_THERMAL_USER_DEFINED DEFINED +Remarks: +Curves and tables are sometimes defined for the purpose of defining material +properties. An example would be a curve of effective stress vs. effective plastic strain +defined using the command *DEFINE_CURVE. In general, the following can be said +about curves and tables that are referenced by material models: +1. Curves are internally rediscretized using equal increments along the 𝑥-axis. +2. Curve data is interpolated between rediscretized data points within the defined +range of the curve and extrapolated as needed beyond the defined range of the +curve. +3. Extrapolation is not employed for table values see the manual entries for the +*DEFINE_TABLE_… keywords. +MATERIAL MODEL REFERENCE TABLES +The tables provided on the following pages list the material models, some of their +attributes, and the general classes of physical materials to which the numerical models +might be applied. +If a material model, without consideration of *MAT_ADD_EROSION, *MAT_ADD_- +THERMAL_EXPANSION, or *MAT_ADD_GENERALIZED_DAMAGE, includes any of +the following attributes, a “Y” will appear in the respective column of the table: +SRATE +FAIL +EOS +- Strain-rate effects +- Failure criteria +- Equation-of-State required for 3D solids and 2D +continuum elements +THERMAL - Thermal effects +ANISO +DAM +TENS +- Anisotropic/orthotropic +- Damage effects +- Tension handled differently than compression in +some manner +Potential applications of the material models, in terms of classes of physical materials, +are abbreviated in the table as follows: +GN - General +CM - Composite +CR - Ceramic +FL +- Fluid +FM - Foam +GL - Glass +HY - Hydrodynamic material +MT - Metal +- Plastic +PL +RB - Rubber +SL +AD - Adhesive or Cohesive material +BIO - Biological material +CIV - Civil Engineering component +HT - Heat Transfer +F +- Soil, concrete, or rock +- Fabric +Y +Y +Material Number And Description +Elastic +Orthotropic Elastic (Anisotropic-solids) +Plastic Kinematic/Isotropic +Y Y +Elastic Plastic Thermal +Soil and Foam +Linear Viscoelastic +Blatz-Ko Rubber +High Explosive Burn +Null Material +Y +Y +Y Y Y +Elastic Plastic Hydro(dynamic) +Y Y +APPS +GN, +FL +CM, +MT +CM, +MT, +PL +MT, +PL +Y FM, SL +RB +RB +HY +FL, +HY +HY, +MT +HY, +MT +MT +Y +Y +Y +Steinberg: Temp. Dependent +Elastoplastic +Isotropic Elastic Plastic +Isotropic Elastic with Failure +Soil and Foam with Failure +Y Y Y Y +Y +Y +Y MT +Y FM, SL +Johnson/Cook Plasticity Model +Y Y Y Y +Y Y +Pseudo Tensor Geological Model +Y Y Y +Y Y +Oriented Crack (Elastoplastic w/ +Fracture) +Y Y +Y +Y +Power Law Plasticity (Isotropic) +Y +Strain Rate Dependent Plasticity +Y Y +Rigid +Orthotropic Thermal (Elastic) +Y Y +HY, +MT +SL +HY, +MT, +PL, CR +MT, +PL +MT, +PL +GN +2-10 (EOS) +LS-DYNA R10.0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +11 +12 +13 +14 +15 +16 +17 +18 +19 +Material Number And Description +Composite Damage +Y +Y +Temperature Dependent Orthotropic +Y Y +Piecewise Linear Plasticity (Isotropic) +Y Y +Inviscid Two Invariant Geologic Cap +Y +Honeycomb +Y Y +Y +Mooney-Rivlin Rubber +Resultant Plasticity +Force Limited Resultant Formulation +Shape Memory +Frazer-Nash Rubber +Laminated Glass (Composite) +Y +Barlat Anisotropic Plasticity (YLD96) +Fabric +Plastic-Green Naghdi Rate +Three-Parameter Barlat Plasticity +Transversely Anisotropic Elastic Plastic +Y +Y +Y +Y +Y +Y Y +Y +Y +Blatz-Ko Foam +FLD Transversely Anisotropic +Nonlinear Orthotropic +-50 User Defined Materials +Y Y Y Y Y Y Y +Y +Y Y +Y +Bamman (Temp/Rate Dependent +Plasticity) +Bamman Damage +Closed cell foam (Low density +polyurethane) +Composite Damage with Chang Failure +Composite Damage with Tsai-Wu Failure +Low Density Urethane Foam +Laminated Composite Fabric +Y +Y Y +Y +Y +Y Y +Y +Y +Y +Y +Y Y Y +Y Y Y +Y +LS-DYNA R10.0 +Y Y Y CM, F +2-11 (EOS) +Y +Y +Y +Y +Y +Y +APPS +CM +CM +MT, +PL +SL +CM, +FM, SL +RB +MT +MT +RB +CM, +GL +CR, +MT +Y +F +MT +MT +MT +FM, +PL +MT +CM +GN +GN +MT +FM +CM +CM +FM +22 +23 +24 +25 +26 +27 +28 +29 +30 +31 +32 +33 +34 +35 +36 +37 +38 +39 +40 +41 +51 +52 +53 +54 +55 +Material Number And Description +Composite Failure (Plasticity Based) +Elastic with Viscosity (Viscous Glass) +Kelvin-Maxwell Viscoelastic +Viscous Foam (Crash dummy Foam) +Isotropic Crushable Foam +Rate Sensitive Powerlaw Plasticity +Y +Y +Y +Y +Y +Y +Y +Y +Y +APPS +CM, +CR +GL +FM +FM +FM +MT +Zerilli-Armstrong (Rate/Temp Plasticity) Y +Y Y +Y MT +Linear Elastic Discrete Beam +Nonlinear Elastic Discrete Beam +Y +Y +Nonlinear Plastic Discrete Beam +Y Y +SID Damper Discrete Beam +Hydraulic Gas Damper Discrete Beam +Cable Discrete Beam (Elastic) +Y +Y +Y +Y +Y +Y +Y Cables +Concrete Damage (incl. Release III) +Y Y Y +Y Y +Low Density Viscous Foam +Elastic Spring Discrete Beam +Bilkhu/Dubois Foam +General Viscoelastic (Maxwell Model) +Hyperelastic and Ogden Rubber +Soil Concrete +Hysteretic Soil (Elasto-Perfectly Plastic) +Ramberg-Osgood +Plasticity with Damage +Plasticity with Damage Ortho +Fu Chang Foam +Winfrith Concrete +Orthotropic Viscoelastic +Cellular Rubber +MTS +Plasticity Polymer +Y Y +Y Y +Y +Y +Y +Y +Y Y +Y Y +Y Y +Y +Y +Y +Y +Y +SL +FM +FM +RB +RB +SL +SL +SL +MT, +PL +Y +Y +Y +Y +Y +Y +Y Y +Y +Y +Y Y +Y +Y Y +Y Y +FM +Y FM, SL +RB +RB +MT +PL +Y +Y +LS-DYNA R10.0 +59 +60 +61 +62 +63 +64 +65 +66 +67 +68 +69 +70 +71 +72 +73 +74 +75 +76 +77 +78 +79 +80 +81 +82 +83 +84 +86 +87 +88 +Material Number And Description +90 +91 +92 +93 +94 +95 +96 +97 +98 +99 +100 +101 +Acoustic +Soft Tissue +Soft Tissue (viscous) +Elastic 6DOF Spring Discrete Beam +Inelastic Spring Discrete Beam +Inelastic 6DOF Spring Discrete Beam +Brittle Damage +General Joint Discrete Beam +Simplified Johnson Cook +Simpl. Johnson Cook Orthotropic +Damage +Spotweld +GE Plastic Strain Rate +Y Y +Y Y +Y Y +Y Y +Y Y +Y Y +Y Y +Y Y +Y Y +102(_T) +Inv. Hyperbolic Sin (Thermal) +Y +Y +103 +103P +Anisotropic Viscoplastic +Anisotropic Plastic +Y Y +Y Y +Y Y +Y +Y Y +Y Y +Y Y +Y +Y +Y +Y +Damage 1 +Damage 2 +Elastic Viscoplastic Thermal +Modified Johnson Cook +Ortho Elastic Plastic +Johnson Holmquist Ceramics +Johnson Holmquist Concrete +Finite Elastic Strain Plasticity +104 +105 +106 +107 +108 +110 +111 +112 +113 +114 +115 +115_O +116 +Unified Creep +Unified Creep Ortho +Composite Layup +Transformation Induced Plasticity (TRIP) +Layered Linear Plasticity +Y Y +APPS +FL +BIO +Y +Y +Y +Y +Y +Y +Y +Y +Y Y Y +SL +Y Y +MT +MT +Y Y MT +Y +Y +Y +Y Y +Y +Y +Y +Y Y +Y Y +Y +Y +PL +MT, +PL +MT +MT +MT +MT +PL +MT +CR, +GL +SL +PL +MT +MT, +PL, +CM +GN +GN +CM +Material Number And Description +117 +118 +119 +120 +121 +122 +Composite Matrix +Composite Direct +General Nonlinear 6DOF Discrete Beam +Gurson +General Nonlinear 1DOF Discrete Beam +Hill 3RC +122_3D Hill 3R 3D +Modified Piecewise Linear Plasticity +Plasticity Compression Tension +Kinematic Hardening Transversely +Aniso. +Y Y +Y Y +Y Y +Y Y +Y Y +Y +Y +Y +Y +Y +Y +123 +124 +125 +126 +127 +128 +129 +130 +131 +132 +133 +134 +135 +136 +138 +139 +140 +141 +142 +143 +Modified Honeycomb +Y Y +Y Y Y +Arruda Boyce Rubber +Heart Tissue +Lung Tissue +Special Orthotropic +Isotropic Smeared Crack +Orthotropic Smeared Crack +Barlat YLD2000 +Viscoelastic Fabric +Y +Y +Y +Y +Y +Y +Y +Y +Y Y +Y Y +Y +Y Y +Weak and Strong Texture Model +Y Y +Corus Vegter +Cohesive Mixed Mode +Modified Force Limited +Vacuum +Y +Y +Y +Y Y Y +Y Y +Rate Sensitive Polymer +Y +Transversely Isotropic Crushable Foam +PL +FM +Y +Wood +Y Y +Y Y Y Wood +2-14 (EOS) +LS-DYNA R10.0 +APPS +CM +CM +Y +Y Y MT +Y +Y +MT +MT, +CM +MT, +PL +MT, +PL +MT +CM, +FM, SL +RB +BIO +BIO +MT, +CM +MT, +CM +MT +MT +Y +Y Y +Y +Y +Y +Y +Y +Y Y +Y Y +Y Y +Y Y +Y Y Y +Material Number And Description +144 +145 +146 +147 +Pitzer Crushable Foam +Schwer Murray Cap Model +1DOF Generalized Spring +FWHA Soil +147N +FHWA Soil Nebraska +Gas Mixture +Evolving Microstructural Model of +Inelast. +148 +151 +153 +154 +155 +156 +157 +158 +159 +160 +Damage 3 +Deshpande Fleck Foam +Y Y +Y +Plasticity Compression Tension EOS +Y Y Y +Muscle +Anisotropic Elastic Plastic +Rate-Sensitive Composite Fabric +CSCM +ALE incompressible +Y +Y Y +Y Y +Y +Y +Y +Y +Y Y Y +Y Y +161,162 +Composite MSC (Dmg) +Y Y +Y Y Y +163 +164 +165 +165B +166 +167 +168 +169 +170 +171 +172 +173 +174 +Modified Crushable Foam +Brain Linear Viscoelastic +Plastic Nonlinear Kinematic +Plastic Nonlinear Kinematic_B +Moment Curvature Beam +McCormick +Polymer +Arup Adhesive +Resultant Anisotropic +Steel Concentric Brace +Concrete EC2 +Mohr Coulomb +RC Beam +Y +Y +Y +Y Y +Y +Y Y +Y +Y +Y +Y +Y +Y +Y +Y Y +Y +Y +Y Y +Y +Y +Y +APPS +FM +SL +SL +SL +FL +MT +MT, +PL +FM +Ice +BIO +MT, +CM +CM +SL +CM +FM +BIO +MT +MT +CIV +MT +PL +AD +PL +CIV +SL, +MT +SL +SL +Y +Y +Material Number And Description +Viscoelastic Thermal +Quasilinear Viscoelastic +Hill Foam +Viscoelastic Hill Foam (Ortho) +Low Density Synthetic Foam +Simplified Rubber/Foam +Simplified Rubber with Damage +Cohesive Elastic +Cohesive TH +Cohesive General +Semi-Analytical Model for Polymers – 1 +Thermo Elasto Viscoelastic Creep +Anisotropic Thermoelastic +Y Y +Y +Y Y +Y Y +Y +Y +Y +Y +Y Y +Y +Y +Y Y +Y +Y +Y Y Y +Y Y +Y Y +Y +Y Y Y +Y Y Y +Y Y +APPS +RB +BIO +FM +FM +FM +RB, +FM +RB +AD +AD +AD +PL +MT +Y +Y Y +Flow limit diagram 3-Parameter Barlat +Y +Seismic Beam +Soil Brick +Drucker Prager +RC Shear Wall +Concrete Beam +General Spring Discrete Beam +Seismic Isolator +Jointed Rock +Steel EC3 +Hysteretic Reinforcement +Bolt Beam +SPR JLR +Dry Fabric +4A Micromec +Elastic Phase Change +Orthotropic Elastic Phase Change +Mooney Rivlin Rubber Phase Change +Y +Y Y +Y +Y Y +Y +Y +Y +Y Y +Y Y +Y Y +Y +Y +Y +Y +Y MT +Y +CIV +Y +Y Y +Y Y +Y +Y +Y +Y Y +SL +SL +CIV +CIV +CIV +SL +CIV +CV +Y Y MT +MT +Y Y Y +Y Y + CM,PL +Y +GN +GN +RB +Y +LS-DYNA R10.0 +175 +176 +177 +178 +179 +181 +183 +184 +185 +186 +187 +188 +189 +190 +191 +192 +193 +194 +195 +196 +197 +198 +202 +203 +208 +211 +214 +215 +216 +217 +Material Number And Description +CODAM2 +Rigid Discrete +Orthotropic Simplified Damage +Y +Y +APPS +Y Y Y +CM +Y Y Y +Tabulated Johnson Cook +Y Y Y Y +Y Y +219 +220 +221 +224 +224_GYS Tabulated Johnson Cook GYS +Y Y Y Y +Y Y +225 +226 +230 +231 +232 +233 +234 +235 +236 +237 +238 +240 +241 +242 +243 +244 +245 +246 +248 +249 +Viscoplastic Mixed Hardening +Y Y +Kinematic hardening Barlat 89 +Elastic Perfectly Matched Layer (PML) +Acoustic PML +Biot Linear Hysteretic Material +Cazacu Barlat +Viscoelastic Loose Fabric +Micromechanic Dry Fabric +Ceramic Matrix +Biot Hysteretic PML +Piecewise linear plasticity (PERT) +Cohesive mixed mode +Johnson Holmquist JH1 +Kinematic hardening Barlat 2000 +Hill 90 +UHS Steel +Orthotropic/anisotropic PML +Null material PML +PHS BMW +Reinforced Thermoplastic +Y +Y +Y Y +Y +Y +Y Y +Y Y +Y Y +Y +Y +Y +Y +LS-DYNA R10.0 +Y +Y +Y +Y +Y +Y Y Y +Y Y +Y +Y Y +Y +Y Y +Y Y +Y +Y MT +Y +Y +Y +CM +HY, +MT, +PL +HY, +MT, +PL +MT, +PL +MT +SL +FL +SL +Fabric +Fabric +CM, +CR +SL +MT, +PL +AD +CR, +GL +MT +MT +MT +SL +FL +MT +Material Number And Description +APPS +249_ +UDfiber +Reinforced Thermoplastic UDfiber +Y Y +Y CM, F +251 +252 +254 +255 +256 +260A +260B +261 +262 +264 +266 +267 +269 +270 +271 +272 +273 +274 +275 +276 +277 +278 +279 +280 +293 +A01 +A02 +A03 +Tailored Properties +Y Y +Toughened Adhesive Polymer +Y Y +Y Y Y Y +Generalized Phase Change +Piecewise linear plastic thermal +Amorphous solid (finite strain) +Stoughton non-associated flow +Y +Y +Y +Y Y +Y +Y +Y MT +Y +Y +Mohr non-associated flow +Y Y +Y Y Y +Laminated Fracture Daimler Pinho +Laminated Fracture Daimler Camanho +Y +Y +Y Y Y +Y Y Y +Tabulated Johnson Cook Orthotorpic +Plasticity +Y Y Y Y Y Y Y +MT, +PL +AD +MT +GL +MT +MT +CM +CM +HY, +MT, +PL +BIO +Dispersed tissue +Eight chain rubber +Bergström Boyce rubber +Welding material +Powder compaction +RHT concrete model +Concrete damage plastic +Paper +Smooth viscoelastic viscoplastic +Chronological viscoelastic +Adhesive curing viscoelastic +CF Micromechanics +Cohesive Paper +Glass +COMPRF +ALE Vacuum +ALE Gas Mixture +ALE Viscous +Y +Y +Y Y +Y Y +Y +Y +Y +Y +Y +Y +Y +Y +Y +RB, PL +RB + MT,PL +Y CR,SL +Y Y SL,CIV +Y Y +SL +Y CM,PL + MT,PL +RB +PL,RB +Y Y +Y Y +Y +Y +Y +Y Y Y +Y +Y +Y +Y +Y +CM +AD +GL +CM +FL +FL +FL +APPS +Material Number And Description +A04 +A05 +A06 +ALE Mixing Length +ALE Incompressible +ALE Herschel +SPH01 +SPH Viscous +S1 +S2 +S3 +S4 +S5 +S6 +S7 +S8 +S13 +S14 +S15 +B1 +T01 +T02 +T03 +T04 +T05 +T07 +T08 +T09 +T10 +T11 +Y +Y +Y +Y +Y +Spring Elastic (Linear) +Damper Viscous (Linear) +Spring Elastoplastic (Isotropic) +Spring Nonlinear Elastic +Damper Nonlinear Viscous +Spring General Nonlinear +Spring Maxwell (3-Parameter +Viscoelastic) +Spring Inelastic (Tension or +Compression) +Spring Trilinear Degrading +Spring Squat Shearwall +Spring Muscle +Seatbelt +Thermal Isotropic +Thermal 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+*MAT_VISCOELASTIC_HILL_FOAM +*MAT_VISCOELASTIC_LOOSE_FABRIC +*MAT_VISCOELASTIC_THERMAL +*MAT_VISCOPLASTIC_MIXED_HARDENING +*MAT_VISCOUS_FOAM +*MAT_142 +*MAT_113 +*MAT_244 +*MAT_115 +*MAT_115_O +*MAT_041-050 +*MAT_140 +*MAT_006 +*MAT_134 +*MAT_178 +*MAT_234 +*MAT_175 +*MAT_225 +*MAT_062 +*MAT_WINFRITH_CONCRETE_REINFORCEMENT +*MAT_084_REINF +*MAT_WINFRITH_CONCRETE +*MAT_WOOD_{OPTION} +*MAT_WTM_STM +*MAT_WTM_STM_PLC +*MAT_084 +*MAT_143 +*MAT_135 +*MAT_135_PLC +*MAT_ADD_AIRBAG_POROSITY_LEAKAGE +This command allows users to model porosity leakage through non-fabric material +when such material is used as part of control volume, airbag. It applies to both +*AIRBAG_HYBRID and *AIRBAG_WANG_NEFSKE. + Card 1 +1 +2 +3 +4 +5 +Variable +MID +FLC/X2 +FAC/X3 +ELA +FVOPT +Type +I +F +F +F +F +8 +6 +X0 +F +7 +X1 +F +Default +none +none +1.0 +none +none +none +none + VARIABLE +DESCRIPTION +MID +Material ID for which the porosity leakage property applies +FLC/X2 +If X0≠0 and X0≠1 +X2 is one of the coefficients of the porosity in the equation of +Anagonye and Wang [1999]. (Defined below in description for +X0/X1) +If X0=0 +GE.0.0: X2, in this context named FLC, is an optional fabric +porous leakage flow coefficient. +LT.0.0: |FLC| is the load curve ID of the curve defining FLC +versus time. +If X0=1 +GE.0.0: See X0=0 above. +LT.0.0: |FLC| is the load curve ID defining FLC versus the +stretching ratio defined as 𝑟𝑠 = 𝐴/𝐴0. See notes below. +FAC/X3 +If X0 ≠ 0 and X0 ≠ 1 +X3 is one of the coefficients of the porosity in the equation of +Anagonye and Wang [1999]. (Defined below in description for +X0/X1) +If X0 = 0 and FVOPT < 7 +GE.0.0: X3, in this context named FAC, is an optional fabric +characteristic parameter. +LT.0.0: |FAC| is the load curve ID of the curve defining FAC +versus absolute pressure. +If X0 = 1 and FVOPT < 7 +GE.0.0: See X0 = 0 and FVOPT < 7 above. +LT.0.0: |FAC| is the load curve ID defining FAC versus the +pressure ratio defined as 𝑟𝑝 = 𝑃air/𝑃bag. See remark 3 +of *MAT_FABRIC. +If (X0 = 0 or X0 = 1) and (FVOPT = 7 or FVOPT = 8) +GE.0.0: See X0 = 0 and FVOPT < 7 above. +LT.0.0: FAC defines leakage volume flux rate versus absolute +pressure. The volume flux (per area) rate (per time) +has the unit of velocity and it is equivalent to relative +porous gas speed. +[ +𝑑(Volflux) +𝑑𝑡 +] = +[volume] +[area] +[time] += +[length] +[time] += [velocity], +ELA +Effective leakage area for blocked fabric, ELA. +LT.0.0: |ELA| is the load curve ID of the curve defining ELA +versus time. The default value of zero assumes that no +leakage occurs. A value of .10 would assume that 10% +of the blocked fabric is leaking gas. +FVOPT +Fabric venting option. +EQ.1: Wang-Nefske formulas for venting through an orifice are +used. Blockage is not considered. +EQ.2: Wang-Nefske formulas for venting through an orifice are +used. Blockage of venting area due to contact is consid- +ered. +EQ.3: Leakage formulas of Graefe, Krummheuer, and Siejak +[1990] are used. Blockage is not considered. +EQ.4: Leakage formulas of Graefe, Krummheuer, and Siejak +[1990] are used. Blockage of venting area due to contact +is considered. +EQ.5: Leakage formulas based on flow through a porous media +are used. Blockage is not considered. +EQ.6: Leakage formulas based on flow through a porous media +are used. Blockage of venting area due to contact is con- +sidered. +EQ.7: Leakage is based on gas volume outflow versus pressure +load curve [Lian, 2000]. Blockage is not considered. +Absolute pressure is used in the porous-velocity-versus- +pressure load curve, given as FAC. +EQ.8: Leakage is based on gas volume outflow versus pressure +load curve [Lian 2000]. Blockage of venting or porous +area due to contact is considered. Absolute pressure is +used in the porous-velocity-versus-pressure load curve, +given as FAC. +X0, X1 +Coefficients of Anagonye and Wang [1999] porosity equation for +the leakage area: +𝐴leak = 𝐴0(𝑋0 + 𝑋1𝑟𝑠 + 𝑋2𝑟𝑝 + 𝑋3𝑟𝑠𝑟𝑝) +*MAT_ADD_COHESIVE +The ADD_COHESIVE option offers the possibility to use a selection of 3-dimensional +material models in LS-DYNA in conjunction with cohesive elements. +Usually the cohesive elements (ELFORM = 19 and 20 of *SECTION_SOLID) can only be +used with a small subset of materials (41-50, 138, 184, 185, 186, 240). But with this +additional keyword, a bigger amount of standard 3-d material models can be used, that +would only be available for solid elements in general. Currently the following material +models are supported: 1, 3, 4, 6, 15, 24, 41-50, 81, 82, 89, 96, 98, 103, 104, 105, 106, 107, +115, 120, 123, 124, 141, 168, 173, 187, 188, 193, 224, 225, 252, and 255. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID +ROFLG +INTFAIL +THICK +Type +I +F +F +F +Default +none +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +PID +Part ID for which the cohesive property applies. +ROFLG +Flag for whether density is specified per unit area or volume. +EQ.0.0: Density specified per unit volume (default). +EQ.1.0: Density specified per unit area for controlling the mass +of cohesive elements with an initial volume of zero. +INTFAIL +The number of integration points required for the cohesive +element to be deleted. If it is zero, the element won’t be deleted +even if it satisfies the failure criterion. The value of INTFAIL may +range from 1 to 4, with 1 the recommended value. +THICK +Thickness of the adhesive layer. +EQ.0.0: The actual thickness of the cohesive element is used. +GT.0.0: User specified thickness. +*MAT +Cohesive elements possess 3 kinematic variables, namely two relative displacements 𝛿1, +𝛿2 in tangential directions and one relative displacement 𝛿3 in normal direction. In a +corresponding constitutive model, they are used to compute 3 associated traction +stresses 𝑡1, 𝑡2, and 𝑡3, e.g. in the elastic case (*MAT_COHESIVE_ELASTIC): +𝑡1 +⎤ = +⎡ +𝑡2 +⎥ +⎢ +𝑡3⎦ +⎣ +𝐸𝑇 +⎡ +⎢ +⎣ +𝐸𝑇 +⎤ +⎥ +𝐸𝑁⎦ +𝛿1 +⎤ +⎡ +𝛿2 +⎥ +⎢ +𝛿3⎦ +⎣ +On the other hand, hypoelastic 3-d material models for standard solid elements are +formulated with respect to 6 independent strain rates and 6 associated stress rates, e.g. +for isotropic elasticity (*MAT_ELASTIC): +𝜎̇𝑥𝑥 +⎤ +⎡ +𝜎̇𝑦𝑦 +⎥ +⎢ +⎥ +⎢ +𝜎̇𝑧𝑧 +⎥ +⎢ +𝜎̇𝑥𝑦 +⎥ +⎢ +⎥ +⎢ +𝜎̇𝑦𝑧 +⎥ +⎢ +𝜎̇𝑧𝑥⎦ +⎣ += +(1 + 𝜈)(1 − 2𝜈) +1 − 𝜈 +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +1 − 𝜈 +1 − 𝜈 +1 − 2𝜈 +1 − 2𝜈 +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +1 − 2𝜈⎦ +𝜀̇𝑥𝑥 +⎤ +⎡ +𝜀̇𝑦𝑦 +⎥ +⎢ +⎥ +⎢ +𝜀̇𝑧𝑧 +⎥ +⎢ +𝜀̇𝑥𝑦 +⎥ +⎢ +⎥ +⎢ +𝜀̇𝑦𝑧 +⎥ +⎢ +𝜀̇𝑧𝑥⎦ +⎣ +To be able to use such 3-dimensional material models in a cohesive element +environment, an assumption is necessary to transform 3 relative displacements to 6 +strain rates. Therefore it is assumed that no lateral expansion and no in-plane shearing +is possible for the cohesive element: +𝛿1 +⎤ +⎡ +𝛿2 +⎥ +⎢ +𝛿3⎦ +⎣ + → +𝜀̇𝑥𝑥 +⎤ +⎡ +𝜀̇𝑦𝑦 +⎥ +⎢ +⎥ +⎢ +𝜀̇𝑧𝑧 +⎥ +⎢ +𝜀̇𝑥𝑦 +⎥ +⎢ +⎥ +⎢ +𝜀̇𝑦𝑧 +⎥ +⎢ +𝜀̇𝑧𝑥⎦ +⎣ += +⎤ +⎡ +⎥ +⎢ +𝛿 ̇ +⎥ +⎢ +3/(𝑡 + 𝛿3) +⎥ +⎢ +⎥ +⎢ +⎥ +⎢ +𝛿 ̇ +2/(𝑡 + 𝛿3) +⎥ +⎢ +𝛿 ̇ +1/(𝑡 + 𝛿3)⎦ +⎣ +where 𝑡 is the initial thickness of the adhesive layer, see parameter THICK. These strain +rates are then used in a 3-d constitutive model to obtain new Cauchy stresses, where 3 +components can finally be used for the cohesive element: +𝜎𝑥𝑥 +⎤ +⎡ +𝜎𝑦𝑦 +⎥ +⎢ +𝜎𝑧𝑧 +⎥ +⎢ +⎥ +⎢ +𝜎𝑥𝑦 +⎥ +⎢ +𝜎𝑦𝑧 +⎥ +⎢ +𝜎𝑧𝑥⎦ +⎣ + → +𝑡1 +⎤ = +⎡ +𝑡2 +⎥ +⎢ +𝑡3⎦ +⎣ +𝜎𝑧𝑥 +⎥⎤ +⎢⎡ +𝜎𝑦𝑧 +𝜎𝑧𝑧⎦ +⎣ +If this keyword is used in combination with a 3-dimensional material model, the output +to D3PLOT or ELOUT is organized as in other material models for cohesive elements, +see e.g. *MAT_184. Instead of the usual six stress components, three traction stresses +are written into those databases. The in-plane shear traction along the 1-2 edge replaces +the x-stress, the orthogonal in-plane shear traction replaces the y-stress, and the traction +in the normal direction replaces the z-stress. +*MAT +Many of the constitutive models in LS-DYNA do not allow failure and erosion. The +ADD_EROSION option provides a way of including failure in these models. This +option can also be applied to constitutive models that already include other +failure/erosion criterion. +For the non-damage options, each of the failure criteria defined here are applied +independently, and once a sufficient number of those criteria are satisfied according to +NCS, the element is deleted from the calculation. +In addition to erosion, the “generalized incremental stress-state dependent damage +model” (GISSMO) or alternative “damage initiation and evolution models” (DIEM) are +available as described in the remarks. See variable IDAM. For DIEM, NCS has a special +meaning, see description below for details. +This option applies to nonlinear element formulations including the 2D continuum +elements, 3D solid elements, 2D and 3D SPH particles, 3D shell elements, and thick +shell elements. Beam formulations 1 and 11 currently support the erosion but not the +damage and evolution models. +NOTE: that all *MAT_ADD_EROSION commands in a +model can be disabled by using *CONTROL_MAT. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +EXCL +MXPRES MNEPS +EFFEPS +VOLEPS +NUMFIP +NCS +Type +A8 +F +F +F +F +F +F +F +Default +none +none +0.0 +0.0 +0.0 +0.0 +1.0 +1.0/0.0 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable MNPRES +SIGP1 +SIGVM +MXEPS +EPSSH +SIGTH +IMPULSE +FAILTM +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +*MAT_ADD_EROSION + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IDAM +DMGTYP +LCSDG +ECRIT +DMGEXP +DCRIT +FADEXP +LCREGD +Type +A8 +F +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +1.0 +0.0 +1.0 +0.0 +Additional card for IDAM > 0. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SIZFLG +REFSZ +NAHSV +LCSRS +SHRF +BIAXF +Type +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Damage Initiation and Evolution Card Pairs. For IDAM < 0 include | IDAM | pairs +of Cards 5 and 6. +5 +6 +7 +8 + Card 5 +1 +Variable +DITYP +Type +F +2 +P1 +F +3 +P2 +F +4 +P3 +F +Default +0.0 +0.0 +0.0 +0.0 +6 +7 +8 +*MAT_ADD_EROSION + Card 6 +1 +2 +Variable +DETYP +DCTYP +Type +F +F +3 +Q1 +F +4 +Q2 +F +Default +0.0 +0.0 +0.0 +0.0 +Optional Card with additional failure criteria. + Card 7 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCFLD +EPSTHIN +ENGCRT RADCRT +Type +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 + VARIABLE +MID +EXCL +DESCRIPTION +Material identification for which this erosion definition applies. +A unique number or label not exceeding 8 characters must be +specified. +The exclusion number, which applies to the failure values defined +on Cards 1, 2, and 7. When any of the failure values on these +cards are set to the exclusion number, the associated failure +criterion is not invoked. Or in other words, only the failure +values not set to the exclusion number are invoked. The default +value of EXCL is 0.0, which eliminates all failure criteria from +consideration that have their constants left blank or set to 0.0. +As an example, to prevent a material from developing tensile +pressure, the user could specify an unusual value for the +exclusion number, e.g., 1234, set MNPRES to 0.0, and set all the +remaining failure values to 1234. However, use of an exclusion +number may be considered nonessential since the same effect +could be achieved without use of the exclusion number by setting +MNPRES to a very small negative value. +MXPRES +*MAT_ADD_EROSION +DESCRIPTION +Maximum pressure at failure, 𝑃max. If the value is exactly zero, it +is automatically excluded to maintain compatibility with old +input files. +MNEPS +Minimum principal strain at failure, 𝜀min. If the value is exactly +zero, it is automatically excluded to maintain compatibility with +old input files. +EFFEPS +Maximum effective strain at failure: +𝜀eff = ∑ √ +𝑖𝑗 +dev𝜀𝑖𝑗 +𝜀𝑖𝑗 +dev +. +If the value is exactly zero, it is automatically excluded to +maintain compatibility with old input files. If the value is +negative, then |EFFEPS| is the effective plastic strain to failure. +In combination with cohesive elements, EFFEPS is the maximum +effective in-plane strain. +VOLEPS +Volumetric strain at failure, +or +𝜀vol = 𝜀11 + 𝜀22 + 𝜀33, +ln(relative volume). +VOLEPS can be a positive or negative number depending on +whether the failure is in tension or compression, respectively. If +the value is exactly zero, it is automatically excluded to maintain +compatibility with old input files. +VARIABLE +NUMFIP +DESCRIPTION +Number of failed integration points prior to element deletion. +The default is unity. See Remark 10. +LT.0.0 (IDAM = 0): Only +is +for shells. + |NUMFIP| +the +percentage of integration points which must +exceed the failure criterion before element +fails. If NUMFIP < -100, then |NUMFIP|- +100 is the number of failed integration points +prior to element deletion. +LT.0.0 (IDAM≠ 0): Only +is +for shells. + |NUMFIP| +the +percentage of layers which must fail before +element fails. For shell formulations with 4 +integration points per layer, the layer is con- +sidered failed if any of the integration points +in the layer fails. +NCS +This meaning of this input depends on whether the damage +option DIEM is used or not. +IDAM.GE.0: Number of failure conditions to satisfy before +failure occurs. For example, if SIGP1 and SIGVM +are defined and if NCS = 2, both failure criteria +must be met before element deletion can occur. +The default is set to unity. +IDAM.LT.0: Plastic strain increment between evaluation of +damage instability and evolution criteria. See DI- +EM description, the default is zero. +MNPRES +Minimum pressure at failure, 𝑃min. +SIGP1 +SIGVM +MXEPS +EPSSH +SIGTH +Principal stress at failure, 𝜎max. +Equivalent stress at failure, 𝜎̅̅̅̅̅max. The equivalent stress at failure +is made a function of the effective strain rate by setting SIGVM to +the negative of the appropriate load curve ID. +Maximum principal strain at failure, 𝜀max. The maximum +principal strain at failure is made a function of the effective strain +rate by setting MXEPS to the negative of the appropriate load +curve ID. +Tensorial shear strain at failure, 𝛾max/2. +Threshold stress, 𝜎0. +*MAT_ADD_EROSION +DESCRIPTION +IMPULSE +Stress impulse for failure, 𝐾f. +FAILTM +Failure time. When the problem time exceeds the failure time, the +material is removed. +IDAM +Flag for damage model. +EQ.0: no damage model is used. +EQ.1: GISSMO damage model. +LT.0: -IDAM represents the number of damage initiation and +evolution model (DIEM) criteria to be applied +DMGTYP +For GISSMO damage type the following applies. +DMGTYP is interpreted digit-wise as follows: +DMGTYP = [𝑁𝑀] = 𝑀 + 10 × 𝑁 +M.EQ.0: Damage is accumulated, no coupling to flow stress, no +failure. +M.EQ.1: Damage is accumulated, element failure occurs for +𝐷 = 1. Coupling of damage to flow stress depending +on parameters, see remarks below. +N.EQ.0: Equivalent plastic strain is the driving quantity for the +damage. (To be more precise, it’s the history variable +that LS-PrePost blindly labels as “plastic strain”. What +this history variable actually represents depends on +the material model.) +N.GT.0: The Nth additional history variable is the driving +quantity for damage. These additional history varri- +ables are the same ones flagged by the *DATABASE_- +EXTENT_BINARY keyword’s NEIPS and NEIPH +fields. For example, for solid elements with *MAT_- +187 setting 𝑁 = 6 chooses volumetric plastic strain as +the driving quantity for the GISSMO damage. +For IDAM.LT.0 the following applies. +EQ.0: No action is taken +EQ.1: Damage history is initiated based on values of initial +plastic strains and initial strain tensor, this is to be +used in multistage analyses +VARIABLE +LCSDG +DESCRIPTION +Load curve ID or Table ID. Load curve defines equivalent plastic +strain to failure vs. triaxiality. Table defines for each Lode +parameter value (between -1 and 1) a load curve ID giving the +equivalent plastic strain to failure vs. triaxiality for that Lode +parameter value. +ECRIT +Critical plastic strain (material instability), see below. +LT.0.0: |ECRIT| is either a load curve ID defining critical +equivalent plastic strain versus triaxiality or a table ID +defining critical equivalent plastic strain as a function +of triaxiality and Lode parameter (as in LCSDG). +EQ.0.0: Fixed value DCRIT defining critical damage is read + +GT.0.0: Fixed value +for stress-state +independent critical +equivalent plastic strain. +DMGEXP +Exponent for nonlinear damage accumulation, see remarks. +DCRIT +Damage threshold value (critical damage). If a Load curve of +critical plastic strain or fixed value is given by ECRIT, input is +ignored. +FADEXP +Exponent for damage-related stress fadeout. +LCREGD +LT.0.0: |FADEXP| is load curve ID defining element-size +dependent fading exponent. +GT.0.0: Constant fading exponent. +Load curve ID defining element size dependent regularization +factors for equivalent plastic strain to failure in the GISSMO +damage model. This feature can also be used with the standard +(non-GISSMO) failure criteria of Cards 1 (MXPRES, MNEPS, +EFFEPS, VOLEPS), 2 (MNPRES, SIGP1, SIGVM, MXEPS, EPSSH, +IMPULSE) and 4 (LCFLD, EPSTHIN), i.e. when IDAM = 0. +*MAT_ADD_EROSION +DESCRIPTION +SIZFLG +Flag for method of element size determination. +EQ.0: (default) Element size is determined in undeformed +configuration as square root of element area (shells), or +cubic root of element volume (solids), respectively. +EQ.1: Element size is updated every time step, and determined +as mean edge length (this option was added to ensure +comparability with *MAT_120, and is not recommended +for general purpose). +Reference element size, for which an additional output of damage +will be generated. This is necessary to ensure the applicability of +resulting damage quantities when transferred to different mesh +sizes. +Number of history variables from damage model which should +be stored in standard material history array for Postprocessing. +See remarks. +Load curve ID defining failure strain scaling factor for LCSDG vs. +strain rate. If the first strain rate value in the curve is negative, it +is assumed that all strain rate values are given as natural +logarithm of the strain rate. The curve should not extrapolate to zero +or failure may occur at low strain. +GT.0: scale ECRIT, too +LT.0: do not scale ECRIT. +Reduction factor for regularization at triaxiality = 0 (shear) +Reduction factor for regularization at triaxiality = 2/3 (biaxial) +Damage initiation type +EQ.0.0: Ductile based on stress triaxiality +EQ.1.0: Shear +EQ.2.0: MSFLD +EQ.3.0: FLD +REFSZ +NAHSV +LCSRS +SHRF +BIAXF +DITYP +EQ.4.0: Ductile based on normalized principal stress +P1 +Damage initiation parameter +DITYP.EQ.0.0: Load curve/table ID representing plastic strain +VARIABLE +DESCRIPTION +at onset of damage as function of stress triaxiali- +ty 𝜂 and optionally plastic strain rate. +DITYP.EQ.1.0: Load curve/table ID representing plastic strain +at onset of damage as function of shear influ- +ence 𝜃 and optionally plastic strain rate. +DITYP.EQ.2.0: Load curve/table ID representing plastic strain +at onset of damage as function of ratio of prin- +cipal plastic strain rates 𝛼 and optionally plastic +strain rate. +DITYP.EQ.3.0: Load curve/table ID representing plastic strain +at onset of damage as function of ratio of prin- +cipal plastic strain rates 𝛼 and optionally plastic +strain rate. +DITYP.EQ.4.0: Load curve/table ID representing plastic strain +at onset of damage as function of stress state pa- +rameter 𝛽 and optionally plastic strain rate. +P2 +Damage initiation parameter +DITYP.EQ.0.0: Not used +DITYP.EQ.1.0: Pressure influence parameter 𝑘𝑠 +DITYP.EQ.2.0: Layer specification +EQ.0: Mid layer +EQ.1: Outer layer +DITYP.EQ.3.0: Layer specification +EQ.0: Mid layer +EQ.1: Outer layer +DITYP.EQ.4.0: Triaxiality influence parameter 𝑘𝑑 +P3 +Damage initiation parameter +DITYP.EQ.0.0: Not used +DITYP.EQ.1.0: Not used +DITYP.EQ.2.0: Initiation formulation +EQ.0: Direct +EQ.1: Incremental +DITYP.EQ.3.0: Initiation formulation +EQ.0: Direct +DESCRIPTION +EQ.1: Incremental +DITYP.EQ.4.0: Not used +*MAT_ADD_EROSION +DETYP +Damage evolution type +EQ.0.0: Linear softening, evolution of damage is a function of +the plastic displacement after the initiation of damage. +EQ.1.0: Linear softening, evolution of damage is a function of +the fracture energy after the initiation of damage. +DCTYP +Damage composition option for multiple criteria +EQ.-1.0: Damage not coupled to stress +EQ.0.0: Maximum +EQ.1.0: Multiplicative +Q1 +Damage evolution parameter +DETYP.EQ.0.0: Plastic displacement at failure, 𝑢𝑓 +value corresponds to a table ID for 𝑢𝑓 +tion of triaxiality and damage. +𝑝, a negative +𝑝 as a func- +Q2 +LCFLD +DETYP.EQ.1.0: Fracture energy at failure, 𝐺𝑓 . +Set to 1.0 to output information to log files (messag and d3hsp) +when an integration point fails. +Load curve ID or Table ID. Load curve defines the Forming Limit +Diagram, where minor engineering strains in percent are defined +as abscissa values and major engineering strains in percent are +defined as ordinate values. Table defines for each strain rate an +associated FLD curve. The forming limit diagram is shown in +Figure M39-1. In defining the curve, list pairs of minor and major +strains starting with the left most point and ending with the right +most point. This criterion is only available for shell elements. +EPSTHIN +Thinning strain at failure for thin and thick shells. +GT.0.0: individual thinning for each integration point from 𝑧- +strain +LT.0.0: averaged thinning strain from element thickness +change +VARIABLE +DESCRIPTION +ENGCRT +Critical energy for nonlocal failure criterion, see Item 9 below. +RADCRT +Critical radius for nonlocal failure criterion, see Item 9 below. +In addition to failure time, supported criteria for failure are: +1. 𝑃 ≥ 𝑃max, where P is the pressure (positive in compression), and 𝑃max is the +maximum pressure at failure. +2. +𝜀3 ≤ 𝜀min, where 𝜀3 is the minimum principal strain, and 𝜀min is the minimum +principal strain at failure. +3. 𝑃 ≤ 𝑃min, where P is the pressure (positive in compression), and 𝑃min is the +minimum pressure at failure. +4. 𝜎1 ≥ 𝜎max, where 𝜎1 is the maximum principal stress, and 𝜎maxis the maximum +principal stress at failure. +5. √3 +′ 𝜎𝑖𝑗 +2 𝜎𝑖𝑗 +′ ≥ 𝜎̅̅̅̅̅max, where 𝜎𝑖𝑗 +equivalent stress at failure. +′ are the deviatoric stress components, and 𝜎̅̅̅̅̅max is the +6. +𝜀1 ≥ 𝜀max, where 𝜀1 is the maximum principal strain, and 𝜀max is the maximum +principal strain at failure. +7. 𝛾1 ≥ 𝛾max/2, where 𝛾1 is the maximum tensorial shear strain = (𝜀1 − 𝜀3)/2, and +𝛾max is the engineering shear strain at failure. +8. The Tuler-Butcher criterion, +∫ [max(0, 𝜎1 +− 𝜎0)]2dt ≥ Kf, +where 𝜎1 is the maximum principal stress, 𝜎0 is a specified threshold stress, +𝜎1 ≥ 𝜎0 ≥ 0, and Kf is the stress impulse for failure. Stress values below the +threshold value are too low to cause fracture even for very long duration load- +ings. +9. A nonlocal failure criterion which is mainly intended for windshield impact can +be defined via ENGCRT, RADCRT, and one additional “main” failure criterion +(only SIGP1 is available at the moment). All three parameters should be de- +fined for one part, namely the windshield glass and the glass should be discre- +tized with shell elements. The course of events of this nonlocal failure model is +as follows: If the main failure criterion SIGP1 is fulfilled, the corresponding +element is flagged as center of impact, but no element erosion takes place yet. +Then, the internal energy of shells inside a circle, defined by RADCRT, around +the center of impact is tested against the product of the given critical energy +ENGCRT and the “area factor”. The area factor is defined as, +Area Factor = +total area of shell elements found inside the circle +2𝜋 × RADCRT2 +The reason for having two times the circle area in the denominator is that we +expect two layers of shell elements, as would typically be the case for laminated +windshield glass.. If this energy criterion is exceeded, all elements of the part +are now allowed to be eroded by the main failure criterion. +10. When IDAM = 0, there are 3 ways to specify how shell elements are eroded and +removed from the calculation. +a) When NUMFIP > 0, elements erode when NUMFIP points fail. +b) When -100 ≤ NUMFIP < 0, elements erode when |NUMFIP| percent of +the integration points fail. +c) When NUMFIP < -100, elements erode when |NUMFIP|-100 integration +points fail. +For NUMFIP > 0 and -100 ≤ NUMFIP < 0, layers retain full strength until the +element is eroded. For NUMFIP < -100, the stress at an integration point im- +mediately drops to zero when failure is detected at that integration point. +When IDAM ≠ 0, there are 2 ways to specify how shell elements are eroded and +removed from the calculation. +a) When NUMFIP > 0, elements erode when NUMFIP points fail. +b) When NUMFIP < 0, elements erode when |NUMFIP| percent of the lay- +ers fail. +A layer fails if any integration point within that layer fails. When IDAM = 0, +erosion is in terms of failed points, not layers. +plastic +failure +strain +compression +-2/3 +-1/3 +tension +1/3 +2/3 +triaxiality +h/σ +vm +Figure 2-1. Typical failure curve for metal sheet, modeled with shell elements. +DAMAGE MODELS +GISSMO: +The GISSMO damage model is a phenomenological formulation that allows for an +incremental description of damage accumulation, including softening and failure. It is +intended to provide a maximum in variability for the description of damage for a +variety of metallic materials (e.g. *MAT_024, *MAT_036, *MAT_103, …). The input of +parameters is based on tabulated data, allowing the user to directly convert test data to +numerical input. +The model is based on an incremental formulation of damage accumulation: +Δ𝐷 = +DMGEXP×𝐷 +𝜀𝑓 +(1− +DMGEXP +) +Δ𝜀𝑝 +where, +𝐷 +𝜀𝑓 +Damage value (0 ≤ 𝐷 ≤ 1). For numerical reasons, 𝐷 is initialized to a +value of 1.E-20 for all damage types in the first time step +Equivalent plastic strain to failure, determined from LCSDG as a function +of the current triaxiality value 𝜂 (and Lode parameter 𝐿 as an option). +A typical failure curve LCSDG for metal sheet, modelled with shell ele- +ments is shown in Figure 2-1 Triaxiality should be monotonically increas- +ing in this curve. A reasonable range for triaxiality is -2/3 to 2/3 if shell +elements are used (plane stress). +For 3-dimensional stress states (solid elements), the possible range of tri- +axiality goes from −∞ to +∞, but to get a good resolution in the internal +load curve discretization (depending on parameter LCINT of *CON- +TROL_SOLUTION) one should define lower limits, e.g. -1 to 1 if +LCINT = 100 (default). +Δ𝜀𝑝 +Equivalent plastic strain increment +For constant values of failure strain, this damage rate can be integrated to get a relation +of damage and actual equivalent plastic strain: +DMGEXP +𝐷 = ( +𝜀𝑝 +𝜀𝑓 +) +, +for 𝜀𝑓 = constant +Triaxiality 𝜂 as a measure of the current stress state is defined as +𝜂 = +𝜎𝐻 +𝜎𝑀 +, +with hydrostatic stress 𝜎𝐻 and equivalent von Mises stress 𝜎𝑀. +Lode parameter 𝐿 as an additional measure of the current stress state is defined as +𝐿 = +27 +𝐽3 +𝜎𝑀 +3 , +with third invariant of the stress deviator 𝐽3. +For DMGTYP.EQ.0, damage is accumulated according to the description above, yet no +softening and failure is taken into account. Thus, parameters ECRIT, DCRIT and +FADEXP will not have any influence. This option can be used to calculate pre-damage +in multi-stage deformations without influencing the simulation results. +For DMGTYP.EQ.1, elements will be deleted if D ≥ 1. +Depending on the set of parameters given by ECRIT (or DCRIT) and FADEXP, a +Lemaitre-type coupling of damage and stress (effective stress concept) can be used. +Three principal ways of damage definition can be used: +1. +Input of a fixed value of critical plastic strain (ECRIT.GT.0.) +As soon as the magnitude of plastic strain reaches this value, the current dam- +age parameter 𝐷 is stored as critical damage DCRIT and the damage coupling +flag is set to unity, in order to facilitate an identification of critical elements in +postprocessing. From this point on, damage is coupled to the stress tensor +using the following relation: +𝜎 = 𝜎̃ +⎢⎡1 − ( +⎣ +𝐷 − DCRIT +1 − DCRIT +FADEXP +) +⎥⎤ +⎦ +This leads to a continuous reduction of stress, up to the load-bearing capacity +completely vanishing as 𝐷 reaches unity. The fading exponent FADEXP can be +defined element size dependent, to allow for the consideration of an element- +size dependent amount of energy to be dissipated during element fade-out. +2. +Input of a load curve defining critical plastic strain vs. triaxiality (ECRIT < 0.), +pointing to load curve ID |ECRIT|. This allows for a definition of triaxiality- +dependent material instability, which takes account of that instability and local- +ization will occur depending on the actual load case. This offers the possibility +to use a transformed Forming Limit Diagram as an input for the expected onset +of softening and localization. Using this load curve, the instability measure 𝐹 is +accumulated using the following relation, which is similar to the accumulation +of damage 𝐷 except for the instability curve is used as an input: +Δ𝐹 = +DMGEXP +𝜀𝑝,𝑙𝑜𝑐 +(1− +DMGEXP +) +Δ𝜀𝑝 +with, +𝐹 +Instability measure (0 ≤ 𝐹 ≤ 1). +𝜀p,loc Equivalent plastic strain to instability, determined from ECRIT +Δ𝜀𝑝 +Equivalent plastic strain increment +As soon as the instability measure 𝐹 reaches unity, the current value of damage +𝐷 in the respective element is stored. Damage will from this point on be cou- +pled to the flow stress using the relation described above +3. +If no input for ECRIT is made, parameter DCRIT will be considered. +Coupling of Damage to the stress tensor starts if this value (damage threshold) is +exceeded (0 ≤ DCRIT ≤ 1). Coupling of damage to stress is done using the +relation described above. +This input allows for the use of extreme values also – for example, DCRIT = 1.0 +would lead to no coupling at all, and element deletion under full load (brittle +fracture). +History Variables: +History variables of the GISSMO damage model are written to the post-processing +database only if NAHSV > 0. + As well, NEIPH and NEIPS must be set in +*DATABASE_EXTENT_BINARY. The damage history variables start at position ND, +which is displayed in d3hsp file, e.g. “first damage history variable = 6” means that +ND = 6. For example, if you wish to view the damage parameter (first GISSMO history +variable) for a *MAT_024 shell element, you must set NEIPS = 6 and NAHSV = 1. In +LS-PrePost, access the damage parameter as history variable #6. +*MAT_ADD_EROSION +ND Damage parameter 𝐷, (10−20 < 𝐷 ≤ 1 ) + ND+1 Damage threshold DCRIT + ND+2 Domain flag for damage coupling (0: no coupling, 1: coupling) + ND+3 +Triaxiality variable 𝜎𝐻/𝜎𝑀 + ND+4 +Equivalent plastic strain + ND+5 Regularization factor for failure strain (determined from LCREGD) + ND+6 +Exponent for stress fading FADEXP + ND+7 Calculated element size + ND+8 +Instability measure F + ND+9 Resultant damage parameter 𝐷 for element size REFSZ + ND+10 Resultant damage threshold DCRIT for element size REFSZ + ND+11 Averaged triaxiality + ND+12 +Lode parameter value (only calculated if LCSDG refers to a table) + ND+13 Alternative damage value: 𝐷1/DMGEXP + ND+14 Averaged Lode parameter +DAMAGE INITIATION AND EVOLUTION CRITERIA: +As an alternative to GISSMO, the user may invoke up to 5 damage initiation and +evolution criteria. For the sake of efficiency, the parameter NCS can be used to only +check these criteria in quantified increments of plastic strain. In other words, the +criteria are only checked when the effective plastic strain goes beyond NCS, 2 × NCS, +3 × NCS, etc. For NCS = 0 the checks are performed in each step there is plastic flow, a +reasonable value of NCS could for instance be NCS = 0.0001. The following theory +applies to the DIEM option. +Assuming that 𝑛 initiation/evolution types have been specified in the input deck +(𝑛 = −IDAM) there is defined at each integration point a damage initiation variable, +𝜔𝐷 +𝑖 , and an evolution history variable 𝐷𝑖, such that, +and +𝑖 ∈ [0, ∞) +𝜔𝐷 +𝐷𝑖 ∈ [0,1], +𝑖 = 1, … 𝑛. +These are initially set to zero and evolve with the deformation of the elements according +to rules associated with the specific damage initiation and evolution type chosen, see +below for details. +These quantities can be post-processed as ordinary material history variables and their +positions in the history variables array is given in d3hsp, search for the string Damage +history listing. The damage initiation variables do not influence the results but serve to +indicate the onset of damage. As an alternative, the keyword *DEFINE_MATERIAL_ +HISTORIES can be used to output the instability and damage, following +*DEFINE_MATERIAL_HISTORIES Properties +Label +Attributes +Description +Instability +Damage +- +- +- +- +- +- +- Maximum +initiation +variable, +𝑖 +max𝑖=1,…,𝑛 𝜔𝐷 +- +Effective damage 𝐷, see below +The damage evolution variables govern the damage in the material and are used to +form the global damage 𝐷 ∈ [0,1]. Each criterion is of either of DCTYP set to maximum +(DCTYP = 0) or multiplicative (DCTYP = 1), or one could choose to not couple damage +to the stress by setting DCTYP = −1. This means that the damage value is calculated +and stored, but it is not affecting the stress as for the other options, so if all DCTYP are +set to −1 there will be no damage or failure. Letting 𝐼max denote the set of evolution +types with DCTYP set to maximum and 𝐼mult denote the set of evolution types with +DCTYP set to multiplicative the global damage, 𝐷, is defined as +where +and, +𝐷 = max(𝐷max, 𝐷mult), +𝐷max = max𝑖∈𝐼max𝐷𝑖 +𝐷mult = 1 − ∏ (1 − 𝐷𝑖) +. +𝑖∈𝐼mult +The damage variable relates the macroscopic (damaged) to microscopic (true) stress by +𝜎 = (1 − 𝐷)𝜎̃ . +Once the damage has reached the level of 𝐷erode (=0.99 by default) the stress is set to +zero and the integration point is assumed failed and not processed thereafter. For +NUMFIP > 0, a shell element is eroded and removed from the finite element model +when NUMFIP integration points have failed. For NUMFIP < 0, a shell element is +eroded and removed from the finite element model when -NUMFIP percent of the +layers have failed. +DAMAGE INITIATION, ωD +For each evolution type 𝑖, 𝜔𝐷 +𝜔𝐷 +algorithms for modelling damage initiation. +𝑖 is independent from the evolution of 𝜔𝐷 +𝑖 governs the onset of damage. For 𝑖 ≠ 𝑗 the evolution of +𝑗 . The following list enumerates the +In this subsection we suppress the superscripted 𝑖 indexing the evolution type. +Ductility Based on Stress Triaxiality (DITYP.EQ.0): +For the ductile initiation option a function 𝜀𝐷 +onset of damage (P1). This is a function of stress triaxiality defined as +𝑝 = 𝜀𝐷 +𝑝 (𝜂, 𝜀̇𝑝) represents the plastic strain at +𝜂 = −𝑝/𝑞 +with p being the pressure and q the von Mises equivalent stress. Optionally this can be +defined as a table with the second dependency being on the effective plastic strain rate +𝜀̇𝑝. The damage initiation history variable evolves according to +Shear (DITYP.EQ.1): +𝜀𝑝 +𝜔𝐷 = ∫ +𝑑𝜀𝑝 +𝜀𝐷 +. +For the shear initiation option a function 𝜀𝐷 +onset of damage (P1). This is a function of a shear stress function defined as +𝑝 (𝜃, 𝜀̇𝑝) represents the plastic strain at +𝑝 = 𝜀𝐷 +𝜃 = (𝑞 + 𝑘𝑆𝑝)/𝜏 +with p being the pressure, q the von Mises equivalent stress and τ the maximum shear +stress defined as a function of the principal stress values +𝜏 = (𝜎major − 𝜎minor)/2. +Introduced here is also the pressure influence parameter 𝑘𝑠 (P2). Optionally this can be +defined as a table with the second dependency being on the effective plastic strain rate +𝜀̇𝑝. The damage initiation history variable evolves according to +𝜀𝑝 +𝜔𝐷 = ∫ +𝑑𝜀𝑝 +𝜀𝐷 +. +*MAT +𝑝 (𝛼, 𝜀̇𝑝) represents the plastic strain at +For the MSFLD initiation option a function 𝜀𝐷 +onset of damage (P1). This is a function of the ratio of principal plastic strain rates +defined as +𝑝 = 𝜀𝐷 +𝛼 = +𝜀̇minor +𝜀̇major +. +The MSFLD criterion is only relevant for shells and the principal strains should be +interpreted as the in-plane principal strains. For simplicity the plastic strain evolution +in this formula is assumed to stem from an associated von Mises flow rule and whence +𝛼 = +𝑠minor +𝑠major +with 𝑠 being the deviatoric stress. This insures that the calculation of 𝛼, is in a sense, +robust at the expense of being slightly innacurate for materials with anisotropic yield +functions and/or non-associated flow rules. Optionally this can be defined as a table +with the second dependency being on the effective plastic strain rate 𝜀̇𝑝. For 𝜀̇𝑝 = 0 the +𝑝 is set to a large number to prevent onset of damage for no plastic evolution. +value of 𝜀𝐷 +Furthermore, the plastic strain used in this failure criteria is a modified effective plastic +strain that only evolves when the pressure is negative, i.e., the material is not affected in +compression. +This modified plastic strain can be monitored as the second history variable of the +initiation history variables in the binary output database. For P3 = 0, the damage +initiation history variable is calculated directly from the ratio of (modified) plastic strain +and the critical plastic strain +𝜔𝐷 = max𝑡≤𝑇 +𝜀𝑝 +𝑝 . +𝜀𝐷 +This should be interpreted as the maximum value up to this point in time. If P3 = 1 the +damage initiation history variable is instead incrementally updated from the ratio of +(modified) plastic strain and the critical plastic strain +𝜀𝑝 +𝜔𝐷 = ∫ +𝑑𝜀𝑝 +𝜀𝐷 +. +For this initiation option P2 is used to determine the layer in the shell where the +criterion is evaluated, if P2 = 0 the criterion is evaluated in the mid-layer only whereas if +P2 = 1 it is evaluated in the outer layers only (bottom and top). This can be used to +distinguish between a membrane instability typically used for FLD evaluations (P2 = 0), +and a bending instability (P2 = 1). As soon as 𝜔𝐷 reaches 1 in any of the integration +points of interest, all integration points in the shell goes over in damage mode, i.e., +subsequent damage is applied to the entire element. +*MAT_ADD_EROSION +The FLD initiation criterion is identical to MSFLD with one subtle difference: the plastic +strain used for evaluating the criteria is not accounting for the sign of the hydrostatic +stress, but is identical to the effective plastic strain directly from the underlying material +model. In other words, it is not the modified plastic strain used in the MSFLD criterion, +but apart from that it is an identical criterion. +Ductile based on normalized principal stress (DITYP.EQ.4): +For the ductile initiation option the plastic strain at the onset of damage (P1) is taken as +a function of 𝛽 and 𝜀̇𝑝, that is 𝜀𝐷 +𝑝 (𝛽, 𝜀̇𝑝), where 𝛽 is the normalized principal stress +𝑝 = 𝜀𝐷 +𝛽 = (𝑞 + 𝑘𝑑𝑝)/𝜎major +where 𝑝 is the pressure, 𝑞 is the von Mises equivalent stress, 𝜎major is the major principal +stress, and where 𝑘𝑑 is the pressure influence parameter specified in the P2 field. +Optionally, this can be defined as a table with the second dependency being on the +effective plastic strain rate 𝜀̇𝑝. The damage initiation history variable evolves according +to +𝜀𝑝 +𝜔𝐷 = ∫ +𝑑𝜀𝑝 +𝜀𝐷 +. +DAMAGE EVOLUTION, 𝑫 +For the evolution of the associated damage variable D we introduce the plastic +displacement 𝑢𝑃 which evolves according to +𝜔𝐷 < 1 +𝑢̇𝑝 = { +𝑙𝜀̇𝑝 𝜔𝐷 ≥ 1 +with 𝑙 being a characteristic length of the element. Fracture energy is related to plastic +displacement as follows +𝑢𝑓 +𝐺𝑓 = ∫ 𝜎𝑦𝑑𝑢̇𝑝 +where 𝜎𝑦 is the yield stress. The following list enumerates the algorithms available for +modelling damage. +Linear (DETYP.EQ.0): +With this option the damage variable evolves linearly with the plastic displacement +𝑢̇𝑝 +𝑝 +𝑢𝑓 +𝑝 being the plastic displacement at failure (Q1). If Q1 is negative, then –Q1 refers +𝑝(𝜂, 𝐷), and +𝑝 as a function of triaxiality and damage, i.e., 𝑢𝑓 +with 𝑢𝑓 +to a table that defines 𝑢𝑓 +importantly the damage evolution law is changed generalized to +𝑝 = 𝑢𝑓 +𝐷̇ = +𝐷̇ = +𝑢̇𝑝 +∂𝑢𝑓 +∂𝐷 +Linear (DETYP.EQ.1): +With this option the damage variable evolves linearly as follows +𝐷̇ = +𝑢̇𝑝 +𝑝 +𝑢𝑓 +where 𝑢𝑓 +𝑝 = 2𝐺𝑓 /𝜎𝑦0 𝑢𝑓 +𝑝 and 𝜎𝑦0 is the yield stress when failure criterion is reached. +*MAT_ADD_FATIGUE +The ADD_FATIGUE option defines the S-N fatigue property of a material model. + Card 1 +1 +2 +3 +Variable +MID +LCID +LTYPE +Type +I +I +Default +none +-1 +I +0 +4 +A +F +5 +B +F +F +I +0 +I +0 +0.0 +0.0 +none +6 +7 +8 +STHRES +SNLIMT +SNTYPE +S-N Curve Segment Cards. Include one card for each additional S-N curve segment. +Between zero and seven of these cards may be included in the deck. This input ends at +the next keyword (“*”) card. + Card 2 +1 +2 +3 +Variable +Type +Default +4 +Ai +F +5 +Bi +F +6 +7 +8 +STHRESi +F +0.0 +0.0 +none + VARIABLE +DESCRIPTION +MID +LCID +Material identification for which the fatigue property applies. +S-N fatigue curve ID. +GT.0: S-N fatigue curve ID +EQ.-1: S-N fatigue curve uses equation 𝑁𝑆𝑏 = 𝑎 +EQ.-2: S-N fatigue curve uses equation log(𝑆) = 𝑎 − 𝑏 log(𝑁) +EQ.-3: S-N fatigue curve uses equation 𝑆 = 𝑎 𝑁𝑏 +LTYPE +Type of S-N curve. +EQ.0: Semi-log interpolation (default) +EQ.1: Log-Log interpolation +EQ.2: Linear-Linear interpolation +VARIABLE +DESCRIPTION +A +B +STHRES +SNLIMT +Material parameter 𝑎 in S-N fatigue equation. +Material parameter 𝑏 in S-N fatigue equation. +Fatigue threshold stress if the S-N curve is defined by equation +(LCID < 0). +If LCID > 0 +SNLIMNT determines the algorithm used when stress is lower +than the lowest stress on S-N curve. +EQ.0: use the life at the last point on S-N curve +EQ.1: extrapolation from the last two points on S-N curve +EQ.2: infinity. +If LCID < 0 +SNLIMIT determines the algorithm used when stress is lower +than STHRES. +EQ.0: use the life at STHRES +EQ.1: Ignored. only applicable for LCID > 0 +EQ.2: infinity. +SNTYPE +Stress type of S-N curve. +EQ.0: stress range (default) +EQ.1: stress amplitude. +Ai +Bi +Material parameter 𝑎 in S-N fatigue equation for the i-th segment. +Material parameter 𝑏 in S-N fatigue equation for the i-th segment. +STHRESi +Fatigue threshold stress for the i-th segment. +Remarks: +1. S-N curves can be defined by *DEFINE_CURVE, or for LCID < 0 by +when LCID = -1 or for LCID = -2 +log(𝑆) = 𝑎 − 𝑏 log(𝑁) +𝑁𝑆𝑏 = 𝑎 +or for LCID = -3 +𝑆 +STHRES2 +STHRES1 +𝑁𝑆𝑏2 = 𝑎2 +𝑁𝑆𝑏1 = 𝑎1 +𝑁 +Figure 2-2. S-N Curve having multiple slopes +𝑆 = 𝑎 𝑁𝑏 +where 𝑁 is the number of cycles for fatigue failure and 𝑆 is the stress amplitude. +Note that the two equations can be converted to each other, with some minor +algebraic manipulation on the constants 𝑎 and 𝑏. +To define S-N curve with multiple slopes, the S-N curve can be split into multi- +ple segments and each segment is defined by a set of parameters Ai, Bi and +STHRESi. Up to 8 sets of the parameters (Ai, Bi and STHRESi) can be defined. +The lower limit of the i-th segment is represented by the threshold stress +STHRESi, as shown in Figure 2-2. This only applies to the case where the S-N +curve is defined by equations (LCID = -1 or LCID = -2) +2. This model is applicable to frequency domain fatigue analysis, defined by the +keywords: *FREQUENCY_DOMAIN_RANDOM_VIBRATION_FATIGUE, and +*FREQUENCY_DOMAIN_SSD_FATIGUE . +*MAT_ADD_GENERALIZED_DAMAGE +This option provides a way of including generalized (tensor type) damage and failure +in standard LS-DYNA material models. The basic idea is to apply a general damage +model (e.g. GISSMO) using several history variables as damage driving quantities at +the same time. With that feature it may be possible to obtain e.g. anisotropic damage +behavior or separate stress degradation for volumetric and deviatoric deformations. A +maximum of three simultaneous damage evolutions (i.e. definition of 3 history +variables) is possible. A detailed description of this model can be found in Erhart et al. +[2017]. +This option currently applies to shell element types 1, 2, 3, 4, 16, and 17 and solid +element types -2, -1, 1, 2, 3, 4, 10, 13, 15, 16, and 17. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +IDAM +DTYP +REFSZ +NUMFIP +PDDT +NHIS +Type +I +Default +none + Card 2 +1 +I +0 +2 +I +0 +3 +F +F +0.0 +1.0 +4 +5 +6 +I +0 +7 +I +1 +8 +Variable +HIS1 +HIS2 +HIS3 +IFLG1 +IFLG2 +IFLG3 +Type +Default +I +0 +I +I +none +none + Card 3 +1 +2 +3 +I +0 +4 +I +0 +5 +I +0 +6 +Variable +D11 +D22 +D33 +D44 +D55 +D66 +Type +I +I +I +I +I +I +Default +none +none +none +none +none +none +7 +(shells) +*MAT_ADD_GENERALIZED_DAMAGE +1 +2 +3 +4 +5 +6 +7 +8 +Variable +D12 +D21 +D24 +D42 +D14 +D41 +Type +I +I +I +I +I +I +Default +none +none +none +none +none +none + Card 4 + (solids) +1 +2 +3 +4 +5 +6 +7 +8 +Variable +D12 +D21 +D23 +D32 +D13 +D31 +Type +I +I +I +I +I +I +Default +none +none +none +none +none +none +Damage definition cards for IDAM = 1 (GISSMO). +2 x NHIS cards have to be defined, i.e. two cards for each history variable. +First Card for history variable HISn: +Card 5… +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCSDG +ECRIT +DMGEXP +DCRIT +FADEXP +LCREG +Type +Default +I +0 +F +F +F +F +0.0 +1.0 +0.0 +1.0 +I +Second Card for history variable HISn: +Card 6… +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCSRS +SHRF +BIAXF +LCDLIM +Type +Default +I +0 +F +F +0.0 +0.0 +I +0 + VARIABLE +DESCRIPTION +MID +Material ID for which this generalized damage definition applies. +IDAM +Flag for damage model. +EQ.0: no damage model is used. +EQ.1: GISSMO damage model. +DTYP +Flag for damage behavior. +EQ.0: Damage is accumulated, no coupling to flow stress, no +failure. +EQ.1: Damage is accumulated, element failure occurs for D = 1. +REFSZ +Reference element size, for which an additional output of damage +will be generated. This is necessary to ensure the applicability of +resulting damage quantities when transferred to different mesh +sizes. +NUMFIP +Number of failed integration points prior to element deletion. +The default is unity. +LT.0: |NUMFIP| is the percentage of layers which must fail +before element fails. +PDDT +NHIS +HISn +*MAT_ADD_GENERALIZED_DAMAGE +DESCRIPTION +Pre-defined damage tensors. + If non-zero, damage tensor +coefficients D11 to D66 on cards 3 and 4 will be ignored. See +remarks for details. +EQ.0: No pre-defined damage tensor is used. +EQ.1: +Isotropic damage tensor. +EQ.2: 2-parameter isotropic damage tensor for volumetric- +deviatoric split. +EQ.3: Anisotropic damage tensor as in MAT_104 (FLAG = - +1). +EQ.4: 3-parameter damage tensor associated with IFLG1 = 2. +Number of history variables as driving quantities (min = 1, +max = 3). +Choice of variable as driving quantity for damage, called “history +value” in the following. +EQ.0: Equivalent plastic strain rate is the driving quantity for +the damage if IFLG1 = 0. Alternatively if IFLG1 = 1, +components of the plastic strain rate tensor are driving +quantities for damage . +GT.0: The rate of the additional history variable HISn is the +driving quantity for damage. IFLG1 should be set to 0. +LT.0: +the damage +*DEFINE_FUNCTION +driving quantities as a function of the components of +the plastic strain rate tensor, IFLG1 should be set to 1. +IDs defining +IFLG1 +Damage driving quantities +EQ.0: Rates of history variables HISn. +EQ.1: Specific components of the plastic strain rate tensor, see +remarks for details. +EQ.2: Predefined functions of plastic strain rate components +for orthotropic damage model, HISn inputs will be ig- +nored, IFLG2 should be set to 1. This option is for shell +elements only. +VARIABLE +DESCRIPTION +IFLG2 +Damage strain coordinate system +EQ.0: Local element system (shells) or global system (solids). +EQ.1: Material system, only applicable for non-isotropic +material models. Supported models for shells: all mate- +rials with AOPT feature. Supported models for solids: +22, 33, 41-50, 103, 122, 157, 233. +EQ.2: Principal strain system (rotating). +EQ.3: Principal +strain +system +(fixed when +instabil- +ity/coupling starts). +IFLG3 +Erosion criteria and damage coupling system +EQ.0: Erosion occurs when one of the damage parameters +computed reaches unity, the damage tensor compo- +nents are based on the individual damage parameters +d1 to d3. +EQ.1: Erosion occurs when a single damage parameter D +reaches unity, the damage tensor components are +based on this single damage parameter. +D11…D31 +LCSDG +DEFINE_FUNCTION IDs for damage tensor coefficients, see +remarks. +Load curve ID defining corresponding history value to failure vs. +triaxiality. +ECRIT +Critical history value (material instability), see below. +LT.0.0: |ECRIT| is load curve ID defining critical history +value vs. triaxiality. +EQ.0.0: Fixed value DCRIT defining critical damage is read. +GT.0.0: Fixed value for stress-state independent critical history +value. +DMGEXP +Exponent for nonlinear damage accumulation. +DCRIT +Damage threshold value (critical damage). If a Load curve of +critical history value or fixed value is given by ECRIT, input is +ignored. +*MAT_ADD_GENERALIZED_DAMAGE +DESCRIPTION +FADEXP +Exponent for damage-related stress fadeout. +LT.0.0: |FADEXP| is load curve ID defining element-size +dependent fading exponent. +GT.0.0: Constant fading exponent. +LCREG +LCSRS +Load curve ID defining element size dependent regularization +factors for history value to failure. +Load curve ID defining failure history value scaling factor for +LCSDG vs. history value rate. If the first rate value in the curve +is negative, it is assumed that all rate values are given as natural +logarithm of the history rate. +GT.0: scale ECRIT, too +LT.0: do not scale ECRIT. +SHRF +Reduction factors for regularization at triaxiality = 0 (shear) +BIAXF +Reduction factors for regularization at triaxiality = 2/3 (biaxial) +Load curve ID defining damage limit values as a function of +triaxiality. Damage can be restricted to values less than 1.0 to +for certain +prevent +triaxialities. +further stress reduction and +failure +LCDLIM +Remarks: +The GISSMO damage model is described in detail in the remarks of *MAT_ADD_ERO- +SION. If NHIS = 1 and HIS1 = 0 is used, this new feature (“MAGD”) behaves just the +same as before (“GISSMO”). The main difference with this new keyword is that up to 3 +independent but simultaneous damage evolutions are possible. Therefore, parameters +LCSDG, ECRIT, DMGEXP, DCRIT, FADEXP, LCREGD, LCSRS, SHRF, BIAXF, and +LCDLIM can be defined separately for each history variable. +The relation between nominal (damaged) stresses 𝜎𝑖𝑗 and effective (undamaged) +stresses 𝜎̃𝑖𝑗 is now expressed as +𝜎11 +⎤ +⎡ +𝜎22 +⎥ +⎢ +𝜎33 +⎥ +⎢ +⎥ +⎢ +𝜎12 +⎥ +⎢ +⎥ +⎢ +𝜎23 +𝜎31⎦ +⎣ += +𝐷11 𝐷12 𝐷13 +⎡ +𝐷21 𝐷22 𝐷23 +⎢ +⎢ +𝐷31 𝐷32 𝐷33 +⎢ +⎢ +⎢ +⎢ +⎣ +0 𝐷44 +𝐷55 +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +𝐷66⎦ +𝜎̃11 +⎤ +⎡ +𝜎̃22 +⎥ +⎢ +⎥ +⎢ +𝜎̃33 +⎥ +⎢ +⎥ +⎢ +𝜎̃12 +⎥ +⎢ +𝜎̃23 +⎥ +⎢ +𝜎̃31⎦ +⎣ +with damage tensor 𝐷. Each damage tensor coefficient 𝐷𝑖𝑗 can be defined via *DE- +FINE_FUNCTION as a function of damage parameters 𝑑1 to 𝑑3. For simple isotropic +damage driven by plastic strain (NHIS = 1, HIS1 = 0, IFLG1 = IFLG2 = IFLG3 = 0) that +would be +𝜎11 +⎤ +⎡ +𝜎22 +⎥ +⎢ +𝜎33 +⎥ +⎢ +⎥ +⎢ +𝜎12 +⎥ +⎢ +⎥ +⎢ +𝜎23 +𝜎31⎦ +⎣ += (1 − 𝑑1) +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +1⎦ +𝜎̃11 +⎤ +⎡ +𝜎̃22 +⎥ +⎢ +⎥ +⎢ +𝜎̃33 +⎥ +⎢ +⎥ +⎢ +𝜎̃12 +⎥ +⎢ +𝜎̃23 +⎥ +⎢ +𝜎̃31⎦ +⎣ +That means the following function should be defined for D11 to D66 (Card 3): +*DEFINE_FUNCTION +1,D11toD66 +func1(d1,d2,d3)=(1.0-d1) +and all entries in Card 4 can be left empty or equal zero in that case. +If GISSMO (IDAM = 1) is used, the damage parameters used in those functions are +internally replaced by +𝑑𝑖 → ( +𝑑𝑖 − 𝐷𝐶𝑅𝐼𝑇𝑖 +1 − 𝐷𝐶𝑅𝐼𝑇𝑖 +𝐹𝐴𝐷𝐸𝑋𝑃𝑖 +) +In the case of plane stress (shell) elements, coupling between normal stresses and shear +stresses is implemented and the damage tensor is defined as below : +𝜎11 +⎤ +⎡ +𝜎22 +⎥ +⎢ +⎥ +⎢ +⎥ +⎢ +𝜎12 +⎥ +⎢ +⎥ +⎢ +𝜎23 +𝜎31⎦ +⎣ += +𝐷11 𝐷12 +⎡ +𝐷21 𝐷22 +⎢ +⎢ +⎢ +⎢ +𝐷41 𝐷42 +⎢ +⎢ +⎣ +0 𝐷14 +0 𝐷24 +𝐷33 +0 𝐷44 +𝐷55 +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +𝐷66⎦ +𝜎̃11 +⎤ +⎡ +𝜎̃22 +⎥ +⎢ +⎥ +⎢ +⎥ +⎢ +𝜎̃12 +⎥ +⎢ +𝜎̃23 +⎥ +⎢ +𝜎̃31⎦ +⎣ +Since the evaluation of *DEFINE_FUNCTION for variables D11 to D66 is relatively time +consuming, pre-defined damage tensors (PDDT) can be used. Currently the following +options are available for shell elements: +PDDT = 1 +(1 − 𝐷1) +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +1⎦ +PDDT = 3 +PDDT = 4 +*MAT_ADD_GENERALIZED_DAMAGE +𝐷1 − 1 +𝐷2 +𝐷2 +⎡1 − 2 +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +𝐷1 − 1 +𝐷2 +𝐷1 − 1 +1 − 2 +𝐷2 +𝐷1 − 1 +1 − 𝐷1 +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +1⎦ +1 − 𝐷1 +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +1 − 𝐷2 +1 − 1 +(𝐷1 + 𝐷2) +1 − 1 +𝐷2 +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +1 − 1 +𝐷1⎦ +1 − 𝐷1 +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +1 − 𝐷2 +1 − 𝐷3 +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +1⎦ +and the following ones for solid elements: +PDDT = +1 +PDDT = +2 +𝐷1 − 1 +𝐷2 +𝐷2 +𝐷2 +⎡1 − 2 +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +𝐷1 − 1 +𝐷1 − 1 +(1 − 𝐷1) +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +1⎦ +𝐷1 − 1 +1 − 2 +𝐷2 +𝐷1 − 1 +𝐷2 +𝐷2 +𝐷1 − 1 +1 − 2 +𝐷1 − 1 +𝐷1 − 1 +𝐷2 +𝐷2 +𝐷1 − 1 +𝐷2 +1 − 𝐷1 +1 − 𝐷1 +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +1 − 𝐷1⎦ +3 +1 − 𝐷1 +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +1 − 𝐷2 +1 − 𝐷3 +1 − 1 +(𝐷1 + 𝐷2) +*MAT +⎤ +1 − 1 +(𝐷2 + 𝐷3) +1 − 1 +(𝐷3 + 𝐷1)⎦ +History Variables: +The increment of the damage parameter is computed in GISSMO based on a driving +quantity that has the dimension of a strain rate : +˙ +𝑑˙ = 𝑛𝑑1−1 𝑛⁄ 𝐻𝐼𝑆𝚤 +𝑒𝑝𝑓 +The history variables defined by the user through HISi should thus have the dimension +of a strain as the rate is computed internally by MAT_ADD_GENERALIZED_DAM- +AGE: +HISı̇ = +HISi(𝑡𝑛+1) − HISi(𝑡𝑛) +𝑡𝑛+1 − 𝑡𝑛 +History variables can either come directly from associated material models (IFLG1 = 0 +and HISi > 0), or they can be equivalent to plastic strain rate tensor components +(IFLG1 = 1 and HISi = 0): +HIṠ 1 = 𝜀̇𝑥𝑥 +𝑝 , HIṠ 2 = 𝜀̇𝑥𝑥 +𝑝 , HIṠ 3 = 𝜀̇𝑥𝑦 +𝑝 (IFLG2 = 0) +HIṠ 1 = 𝜀̇𝑎𝑎 +𝑝 , HIṠ 2 = 𝜀̇𝑏𝑏 +𝑝, HIṠ 2 = 𝜀̇2 +𝑝 (IFLG2 = 1) +𝑝 , HIṠ 3 = 𝜀̇𝑎𝑏 +𝑝, HIṠ 3 = 0 (IFLG2 = 2) +HIṠ 1 = 𝜀̇1 +or they can be provided via *DEFINE_FUNCTIONs by the user (IFLG1 = 1 and +HISi < 0): +HIṠ +𝑖 = 𝑓𝑖(𝜀̇𝑥𝑥 +𝑝 , 𝜀̇𝑦𝑦 +𝑝 , 𝜀̇𝑧𝑧 +𝑝 , 𝜀̇𝑥𝑦 +𝑝 , 𝜀̇𝑦𝑧 +𝑝 , 𝜀̇𝑧𝑥 +𝑝 ) (IFLG2 = 0) +HIṠ +𝑖 = 𝑓𝑖(𝜀̇𝑎𝑎 +𝑝 , 𝜀̇𝑏𝑏 +𝑝 , 𝜀̇𝑧𝑧 +𝑝 , 𝜀̇𝑎𝑏 +𝑝 , 𝜀̇𝑏𝑧 +𝑝 , 𝜀̇𝑧𝑎 +𝑝 ) (IFLG2 = 1) +HIṠ +𝑖 = 𝑓𝑖(𝜀̇1 +𝑝, 𝜀̇2 +𝑝) (IFLG2 = 2) +e.g. the following example defines a history variable (HISi = -1234) as function of the +transverse shear strains in material coordinate system a-b-z for shells: +*DEFINE_FUNCTION + 1234 +fhis1(eaa,ebb,ezz,eab,ebz,eza)=1.1547*sqrt(ebz**2+eza**2) +The plastic strain rate tensor is not always available in the material law and is estimated +as: +𝛆̇𝑝 = +𝜀̇𝑒𝑓𝑓 +𝜀̇𝑒𝑓𝑓 +[𝛆̇ − +𝜀̇𝒗𝒐𝒍 +𝛅] +This is a good approximation for isochoric materials with small elastic strains (e.g. +metals) and correct for J2 plasticity. +The following table gives an overview of the driving quantities used for incrementing +the damage in function of the input parameters (strain superscript “p” for “plastic” is +omitted for convenience): +IFLG1 +IFLG2 +HISi > 0 +HISi = 0 +HISi < 0 +0 +0 +0 +1 +1 +1 +2 +2 +2 +0 +1 +2 +0 +1 +2 +0 +1 +2 +˙ +HISı +˙ +HISı +˙ +HISı +N/A +N/A +N/A +𝜀˙ +N/A +N/A +𝜀˙𝑖𝑗 +𝑚𝑎𝑡 +𝜀˙𝑖𝑗 +𝜀˙𝑖 +N/A +N/A +N/A +𝑓 (𝜀˙𝑖𝑗) +𝑓 (𝜀˙𝑖𝑗 +𝑚𝑎𝑡) +𝑓 (𝜀˙𝑖) +N/A +Preprogrammed functions of plastic strain rate +N/A +Postprocessing History Variables: +History variables of the GENERALIZED_DAMAGE model are written to the post- +processing database behind those already occupied by the material model which is used +in combination: + Variable Description +ND +Triaxiality variable 𝜎𝐻/𝜎𝑀 + ND+1 +Lode parameter value + ND+2 +Single damage parameter 𝐷, (10−20 < 𝐷 ≤ 1 ), only for IFLG3 = 1 +ND+3 Damage parameter 𝑑1 + ND+4 Damage parameter 𝑑2 + ND+5 Damage parameter 𝑑3 + ND+6 Damage threshold DCRIT1 + ND+7 Damage threshold DCRIT2 + ND+8 Damage threshold DCRIT3 + ND+12 History variable HIS1 + ND+13 History variable HIS2 + ND+14 History variable HIS3 + ND+15 Angle between principal and material axes + ND+21 Characteristic element size (used in LCREG) +For instance, ND = 6 for *MAT_024, ND = 9 for *MAT_036, or ND = 23 for *MAT_187. +Exact information of the variable locations can be found in the d3hsp section “MAGD +damage history listing”. +For consolidation calculations. +*MAT_ADD_PERMEABILITY + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +PERM +(blank) +(blank) +THEXP +LCKZ +Type +I +F +F +I +Default +none +none +0.0 +none + VARIABLE +DESCRIPTION +MID +Material identification – must be same as the structural material. +PERM +Permeability +THEXP +Undrained volumetric thermal expansion coefficient +(Units: 1/temperature). If negative, then –THEXP is the ID of a +loadcurve giving thermal expansion coefficient (y-axis) versus +temperature (x-axis). +LCKZ +Loadcurve giving factor on PERM versus z-coordinate. +(X-axis – z-coordinate, yaxis – non dimensional factor) +Remarks: +The units of PERM are length/time (volume flow rate of water per unit area per +gradient of pore pressure head). +THEXP represents the thermal expansion of the material caused by the pore fluid. It +should be set equal to nαw, where n is the porosity of the soil and αw is the volumetric +thermal expansion coefficient of the pore fluid. If the pore fluid is water, the thermal +expansion coefficient varies strongly with temperature; a curve of coefficient versus +temperature may be input instead of a constant value. +See notes under *CONTROL_PORE_FLUID +For pore air pressure calculations. +*MAT + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +PA_RHO +PA_PRE +PORE +Type +I +I +F +F +Default +none AIR_RO AIR_RO +1. +Remarks +1 +1, 2 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PERM1 +PERM2 +PERM3 +CDARCY +CDF +LCPGD1 +LCPGD2 +LCPGD3 +Type +F +F +F +F +F +I +I +I +Default +0. +PERM1 PERM1 +1. +0. +none LCPGD1 LCPGD1 +Remarks 2, 3, 4, 5 2, 3, 4, 5 2, 3, 4, 5 +1 +1, 5 +6 +6 +6 + VARIABLE +DESCRIPTION +MID +Material identification – must be same as the structural material. +PA_RHO +PA_PRE +Initial density of pore air, default to atmospheric air density, +AIR_RO, defined in *CONTROL_PORE_AIR +Initial pressure of pore air, default to atmospheric air pressure, +AIR_P, defined in *CONTROL_PORE_AIR +PORE +Porosity, ratio of pores to total volume, default to 1. +PERM[1-3] +Permeability of pore air along 𝑥, 𝑦 and 𝑧-direction. If less than 0 – +PERM[1-3] is taken to be the curve ID defining the permeability +coefficient as a function of volume ratio of current volume to +volume in the stress free state. +*MAT_ADD_PORE_AIR +DESCRIPTION +CDARCY +Coefficient of Darcy’s law +CDF +Coefficient of Dupuit-Forchheimer law +LCPGD1~3 +Curves defining non-linear Darcy’s laws along x, y and z- +directions, see Remarks 6. +Remarks: +1. Card 1. This card must be defined for all materials requiring consideration of +pore air pressure. The pressure contribution of pore air is (𝜌 − 𝜌atm)RT× +PORE, where 𝜌 and 𝜌atm are the current and atmospheric air density, 𝑅 is air’s +gas constant, 𝑇 is atmospheric air temperature and PORE is the porosity. The +values for 𝑅, 𝑇 and PORE are assumed to be constant during simulation. +2. Permeability Model. The unit of PERMi is [Length]3[time]/[mass], (air flow +velocity per gradient of excess pore pressure), i.e. +(CDARCY + CDF × |𝑣𝑖|) × PORE × 𝑣𝑖 = PERM𝑖 × +𝜕𝑃𝑎 +𝜕𝑥𝑖 +, +𝑖 = 1,2,3 +where 𝑣i is the pore air flow velocity along the ith direction, 𝜕𝑃𝑎/𝜕𝑥𝑖 is the pore +air pressure gradient along the ith direction, and 𝑥1 = 𝑥, 𝑥2 = 𝑦, 𝑥3 = 𝑧. +3. Default Values for PERM2 and PERM3. PERM2 and PERM3 are assumed to +be equal to PERM1 when they are not defined. A definition of “0” means no +permeability. +4. Local Coordinate Systems. (x,y,z), or (1,2,3), refers to the local material +coordinate system (a,b,c) when MID is an orthotropic material, such as *MAT_- +002 or *MAT_142; otherwise it refers to the global coordinate system. +5. CDF for Viscosity. CDF can be used to consider the viscosity effect for high +speed air flow +6. Nonlinearity. LCPGDi can be used to define a non-linear Darcy’s law as +follows: +(CDARCY + CDF × |𝑣𝑖|) × PORE × 𝑣𝑖 = PERM𝑖 × 𝑓𝑖 +𝜕𝑃𝑎 +𝜕𝑥𝑖 +, +𝑖 = 1,2,3 +where 𝑓𝑖 is value of the function defined by the LCPGDi field. The linear ver- +siono Darcy’s law of Remark 2, can be recovered when the LCPGDi curves are +defined as straight lines of slope of 1. +*MAT +The ADD_THERMAL_EXPANSION option is used to occupy an arbitrary material +model in LS-DYNA with a thermal expansion property. This option applies to all +nonlinear solid, shell, thick shell and beam elements and all material models except +those models which use resultant formulations such as *MAT_RESULTANT_PLASTIC- +ITY and + Orthotropic expansion effects are +supported for anisotropic materials. + *MAT_SPECIAL_ORTHOTROPIC. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID +LCID +MULT +LCIDY +MULTY +LCIDZ +MULTZ +Type +I +I +F +I +F +I +F +Default +none +none +1.0 +LCID MULT +LCID MULT + VARIABLE +DESCRIPTION +PID +LCID +MULT +LCIDY +Part ID for which the thermal expansion property applies +For isotropic material models, LCIDY, MULTY, LCIDZ, and +MULTZ are ignored, and LCID is the load curve ID defining the +thermal expansion coefficient as a function of temperature. If +zero, the thermal expansion coefficient is constant and equal to +MULT. For anisotropic material models, LCID and MULT define +the thermal expansion coefficient in the local material a-direction. +Scale factor scaling load curve given by LCID. +Load curve ID defining the thermal expansion coefficient in local +material b-direction as a function of temperature. If zero, the +thermal expansion coefficient in the local material b-direction is +constant and equal to MULTY. If MULTY = 0 as well, LCID and +MULT define the thermal expansion coefficient in the local +material b-direction. +MULTY +Scale factor scaling load curve given by LCIDY. +LCIDZ +*MAT_ADD_THERMAL_EXPANSION +DESCRIPTION +Load curve ID defining the thermal expansion coefficient in local +material c-direction as a function of temperature. If zero, the +thermal expansion coefficient in the local material c-direction is +constant and equal to MULTZ. If MULTZ = 0 as well, LCID and +MULT define the thermal expansion coefficient in the local +material c-direction. +MULTZ +Scale factor scaling load curve given by LCIDZ. +Remarks: +When invoking the isotropic thermal expansion property (no use of the local y and z +parameters) for a material, the stress update is based on the elastic strain rates given by +𝑒 = 𝜀̇𝑖𝑗 − 𝛼(𝑇)𝑇̇𝛿𝑖𝑗 +𝜀̇𝑖𝑗 +rather than on the total strain rates 𝜀̇𝑖𝑗. For a material with the stress based on the +deformation gradient 𝐹𝑖𝑗, the elastic part of the deformation gradient is used for the +stress computations +𝑒 = 𝐽𝑇 +𝐹𝑖𝑗 +���1/3𝐹𝑖𝑗 +where 𝐽𝑇 is the thermal Jacobian. The thermal Jacobian is updated using the rate given +by +𝐽 ̇𝑇 = 3𝛼(𝑇)𝑇̇𝐽𝑇. +For orthotropic properties, which apply only to materials with anisotropy, these +equations are generalized to +and +where the 𝛽𝑖 are updated as +𝑒 = 𝜀̇𝑖𝑗 − 𝛼𝑘(𝑇)𝑇̇𝑞𝑖𝑘𝑞𝑗𝑘 +𝜀̇𝑖𝑗 +𝑒 = 𝐹𝑖𝑘𝛽𝑙 +𝐹𝑖𝑗 +−1𝑄𝑘𝑙𝑄𝑗𝑙 +𝛽̇ +𝑖 = 𝛼𝑖(𝑇)𝑇̇𝛽𝑖. +Here 𝑞𝑖𝑗 represents the matrix with material directions with respect to the current +configuration whereas 𝑄𝑖𝑗 are the corresponding directions with respect to the initial +configuration. For (shell) materials with multiple layers of different anisotropy +directions, the mid surface layer determines the orthotropy for the thermal expansion. +*MAT +In nonlocal failure theories, the failure criterion depends on the state of the material +within a radius of influence which surrounds the integration point. An advantage of +nonlocal failure is that mesh size sensitivity on failure is greatly reduced leading to +results which converge to a unique solution as the mesh is refined. +Without a nonlocal criterion, strains will tend to localize randomly with mesh +refinement leading to results which can change significantly from mesh to mesh. The +nonlocal failure treatment can be a great help in predicting the onset and the evolution +of material failure. This option can be used with two and three-dimensional solid +elements, and three-dimensional shell elements and thick shell elements. This option +applies to a subset of elastoplastic materials that include a damage-based failure +criterion. + Card 1 +1 +2 +Variable +IDNL +PID +Type +I +I +3 +P +F +4 +Q +F +5 +L +F +6 +7 +8 +NFREQ +NHV +I +I +Default +none +none +none +none +none +none +none +History Cards. Include as many cards as needed to set NHV variables. One card 2 will +be read even if NHV = 0. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NL1 +NL2 +NL3 +NL4 +NL5 +NL6 +NL7 +NL8 +Type +I +I +I +I +I +I +I +I +Default +none +none +none +none +none +none +none +none +Symmetry Plane Cards. Define one card for each symmetry plane. Up to six +symmetry planes can be defined. The next “*” card terminates this input. + Cards 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +XC1 +YC1 +ZC1 +XC2 +YC2 +ZC2 +Type +F +F +F +F +F +F +Default +none +none +none +none +none +none + VARIABLE +DESCRIPTION +IDNL +PID +Nonlocal material input ID. +Part ID for nonlocal material. +P +Q +L +NFREQ +Exponent of weighting function. A typical value might be 8 +depending somewhat on the choice of L. See equations below. +Exponent of weighting function. A typical value might be 2. +See equations below. +Characteristic length. This length should span a few elements. +See equations below. +Number of time steps between searching for integration points +that lie in the neighborhood. Nonlocal smoothing will be done +each cycle using these neighbors until the next search is done. +The neighbor search can add significant computational time so it +is suggested that NFREQ be set to value of 10 to 100 depending +on the problem. This parameter may be somewhat problem +dependent. If NFREQ = 0, a single search will be done at the +start of the calculation. +NHV +Define the number of history variables for nonlocal treatment. +NL1, …, NL8 +Identifies the history variable(s) for nonlocal treatment. Define +NHV values (maximum of 8 values per line). +XC1, YC1, ZC1 +Coordinate of point on symmetry plane. +XC2, YC2, ZC2 +Coordinate of a point along the normal vector. +*MAT +For elastoplastic material models in LS-DYNA which use the plastic strain as a failure +criterion, setting the variable NL1 to 1 would tag plastic strain for nonlocal treatment. +A sampling of other history variables that can be tagged for nonlocal treatment are +listed in the table below. The value in the third column in the table below corresponds +to the history variable number as tabulated at http://www.dynasupport.com/howtos- +/material/history-variables. Note that the NLn value is the history variable number +plus 1. +Material Model Name +JOHNSON_COOK +PLASTICITY_WITH_DAMAGE +DAMAGE_1 +DAMAGE_2 +JOHNSON_HOLMQUIST_CONCRETE +GURSON +15 +81 +104 +105 +111 +120 +*MAT_NONLOCAL +NLn Value +History Variable +Number +5 (shells); 7 (solids) +4 (shells); 6 (solids) +2 +4 +2 +2 +2 +1 +3 +1 +1 +1 +In applying the nonlocal equations to shell and thick shell elements, integration points +lying in the same plane within the radius determined by the characteristic length are +considered. Therefore, it is important to define the connectivity of the shell elements +consistently within the part ID, e.g., so that the outer integration points lie on the same +surface. +The equations and our implementation are based on the implementation by Worswick +and Lalbin [1999] of the nonlocal theory to Pijaudier-Cabot and Bazant [1987]. Let Ω𝑟 +be the neighborhood of radius, L, of element 𝑒𝑟 and {𝑒𝑖}𝑖=1,...,𝑁𝑟 the list of elements +included in Ω𝑟, then +𝑟 = 𝑓 ̇(𝑥𝑟) = +𝑓 ̇ +𝑊𝑟 +local𝑤(𝑥𝑟 − 𝑦) +∫ 𝑓 ̇ +𝛺𝑟 +𝑑𝑦 ≈ +𝑊𝑟 +𝑁𝑟 +∑ 𝑓 ̇ +𝑖=1 +local +𝑤𝑟𝑖 +𝑉𝑖 +where +𝑊𝑟 = 𝑊(𝑥𝑟) = ∫ 𝑤(𝑥𝑟 − 𝑦) 𝑑𝑦 ≈ ∑ 𝑤𝑟𝑖𝑉𝑖 +𝑁𝑟 +𝑤𝑟𝑖 = 𝑤(𝑥𝑟 − 𝑦𝑖) = +𝑖=1 +[1 + ( +∥𝑥𝑟 − 𝑦𝑖∥ +𝑞 +) +] +Figure 2-3. Here 𝑓 ̇ +𝑟 and 𝑥𝑟 are respectively the nonlocal rate of increase of +damage and the center of the element 𝑒𝑟, and 𝑓 ̇ +, 𝑉𝑖 and 𝑦𝑖 are respectively +local +the local rate of increase of damage, the volume and the center of element 𝑒𝑖. +*MAT_001 +This is Material Type 1. This is an isotropic hypoelastic material and is available for +beam, shell, and solid elements in LS-DYNA. A specialization of this material allows +the modeling of fluids. +Available options include: + +FLUID +such that the keyword cards appear: +*MAT_ELASTIC or MAT_001 +*MAT_ELASTIC_FLUID or MAT_001_FLUID +The fluid option is valid for solid elements only. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +DA +F +6 +DB +F +7 +K +F +8 +Default +none +none +none +0.0 +0.0 +0.0 +0.0 +Additional card for FLUID keyword option. +3 +4 +5 +6 +7 +8 + Card 2 +Variable +1 +VC +Type +F +2 +CP +F +Default +none 1.0E+20 + VARIABLE +MID +LS-DYNA R10.0 +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +*MAT_ELASTIC +DESCRIPTION +Mass density. +Young’s modulus. +Poisson’s ratio. +Axial damping factor (used for Belytschko-Schwer beam, type 2, +only). +Bending damping factor (used for Belytschko-Schwer beam, type +2, only). +Bulk Modulus (define for fluid option only). +Tensor viscosity coefficient, values between .1 and .5 should be +okay. +Cavitation pressure (default = 1.0e+20). +RO +E +PR +DA +DB +K +VC +CP +Remarks: +This hypoelastic material model may not be stable for finite (large) strains. If large +strains are expected, a hyperelastic material model, e.g., *MAT_002, would be more +appropriate. +The axial and bending damping factors are used to damp down numerical noise. The +update of the force resultants, 𝐹𝑖, and moment resultants, 𝑀𝑖, includes the damping +factors: +𝑛+1 = 𝐹𝑖 +𝐹𝑖 +𝑛 + (1 + +𝑛+1 +2 +) Δ𝐹𝑖 +𝐷𝐴 +Δ𝑡 +𝑀𝑖 +𝑛+1 = 𝑀𝑖 +𝑛 + (1 + +𝑛+1 +2 +) Δ𝑀𝑖 +𝐷𝐵 +Δ𝑡 +The history variable labeled as “plastic strain” by LS-PrePost is actually volumetric +strain in the case of *MAT_ELASTIC. +Truss elements include a damping stress given by +𝜎 = 0.05𝜌𝑐𝐿/𝛥𝑡 +where ρ is the mass density, 𝑐 is the material wave speed, 𝐿 is the element length, and 𝛥𝑡 +is the computation time step. +For the fluid option, the bulk modulus field, 𝐾, must be defined, and both the Young’s +modulus and Poisson’s ratio fields are ignored. With the fluid option, fluid-like +behavior is obtained where the bulk modulus, 𝐾, and pressure rate, 𝑝, are given by: +𝐾 = +3(1 − 2𝜈) +𝑝̇ = −𝐾𝜀̇𝑖𝑖 +and the shear modulus is set to zero. A tensor viscosity is used which acts only the +𝑛+1, given in terms of the damping coefficient as: +deviatoric stresses, 𝑆𝑖𝑗 +𝑛+1 = VC × Δ𝐿 × 𝑎 × 𝜌𝜀̇𝑖𝑗 +′ +𝑆𝑖𝑗 +where Δ𝐿 is a characteristic element length, 𝑎 is the fluid bulk sound speed, 𝜌 is the fluid +density, and 𝜀̇𝑖𝑗 +′ is the deviatoric strain rate. +*MAT_OPTIONTROPIC_ELASTIC +This is Material Type 2. This material is valid for modeling the elastic-orthotropic +behavior of solids, shells, and thick shells. An anisotropic option is available for solid +elements. For orthotropic solids an isotropic frictional damping is available. +In the case of solids, stresses are calculated not from incremental strains but rather from +the deformation gradient. Also for solids, the elastic constants are formulated in terms +of second Piola-Kirchhoff stress and Green’s strain, however, Cauchy stress is output. +In the case of shells, the stress update is incremental and the elastic constants are +formulated in terms of Cauchy stress and true strain. +NOTE: This material does not support specification of a ma- +terial angle, 𝛽𝑖, for each through-thickness integra- +tion point of a shell. +Available options include: +ORTHO +ANISO +such that the keyword cards appear: +*MAT_ORTHOTROPIC_ELASTIC or MAT_002 +(4 cards follow) +*MAT_ANISOTROPIC_ELASTIC or MAT_002_ANIS +(5 cards follow) +Orthotropic Card 1. Card 1 for ORTHO keyword option. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +EA +F +4 +EB +F +5 +EC +F +6 +7 +8 +PRBA +PRCA +PRCB +F +F +F +Orthotropic Card 2. Card 2 for ORTHO keyword option. + Card 2 +1 +2 +3 +4 +Variable +GAB +GBC +GCA +AOPT +Type +F +F +F +F +5 +G +F +6 +7 +8 +SIGF +Anisotropic Card 1. Card 1 for ANISO keyword option. + Card 1 +1 +Variable +MID +2 +RO +3 +4 +5 +6 +7 +8 +C11 +C12 +C22 +C13 +C23 +C33 +Type +A8 +F +F +F +F +F +F +F +Anisotropic Card 2. Card 2 for ANISO keyword option. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +C14 +C24 +C34 +C44 +C15 +C25 +C35 +C45 +Type +F +F +F +F +F +F +F +F +Anisotropic Card 3. Card 3 for ANISO keyword option. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +C55 +C16 +C26 +C36 +C46 +C56 +C66 +AOPT +Type +F +F +F +F +F +F +F +F +Local Coordinate System Card 1. Required for all keyword options + Card 4 +Variable +1 +XP +Type +F +2 +YP +F +3 +ZP +F +4 +A1 +F +5 +A2 +F +6 +A3 +F +7 +8 +MACF +IHIS +I +Local Coordinate System Card 2. Required for all keyword options + Card 5 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +BETA +REF +F +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +Define for the ORTHO option only: +EA +EB +EC +PRBA +PRCA +PRCB +GAB +GBC +GCA +𝐸𝑎, Young’s modulus in 𝑎-direction. +𝐸𝑏, Young’s modulus in 𝑏-direction. +𝐸𝑐, Young’s modulus in 𝑐-direction (nonzero value required but +not used for shells). +𝜈𝑏𝑎, Poisson’s ratio in the 𝑏𝑎 direction. +𝜈𝑐𝑎, Poisson’s ratio in the 𝑐𝑎 direction. +𝜈𝑐𝑏, Poisson’s ratio in the 𝑐𝑏 direction. +𝐺𝑎𝑏, shear modulus in the 𝑎𝑏 direction. +𝐺𝑏𝑐, shear modulus in the 𝑏𝑐 direction. +𝐺𝑐𝑎, shear modulus in the 𝑐𝑎 direction. +Due to symmetry define the upper triangular Cij’s for the ANISO option only: +C11 +C12 +⋮ +C66 +The 1, 1 term in the 6 × 6 anisotropic constitutive matrix. Note +that 1 corresponds to the a material direction +The 1, 2 term in the 6 × 6 anisotropic constitutive matrix. Note +that 2 corresponds to the b material direction +The 6, 6 term in the 6 × 6 anisotropic constitutive matrix. +⋮ +Define AOPT for both options: +AOPT +Material axes option, see Figure M2-1. +EQ.0.0: locally orthotropic with material axes determined by +element nodes as shown in part (a) of Figure M2-1. +The 𝐚-direction is from node 1 to node 2 of the element. +The 𝐛-direction is orthogonal to the a-direction and is +in the plane formed by nodes 1, 2, and 4. When this +option is used in two-dimensional planar and axisym- +metric analysis, it is critical that the nodes in the ele- +ment definition be numbered counterclockwise for this +option to work correctly. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the 𝐚-direction. This option is for solid +elements only. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector 𝐯 with the +element normal. The plane of a solid element is the +midsurface between the inner surface and outer surface +defined by the first four nodes and the last four nodes +of the connectivity of the element, respectively. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector 𝐯, and +an originating point, 𝐏, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +G +Shear modulus for frequency independent damping. Frequency +independent damping is based of a spring and slider in series. +The critical stress for the slider mechanism is SIGF defined below. +For the best results, the value of G should be 250-1000 times +greater than SIGF. This option applies only to solid elements. +SIGF +Limit stress for frequency independent, frictional, damping. +XP, YP, ZP +Define coordinates of point 𝐩 for AOPT = 1 and 4. +A1, A2, A3 +Define components of vector 𝐚 for AOPT = 2. +MACF +Material axes change flag for brick elements: +EQ.1: No change, default, +EQ.2: switch material axes 𝑎 and 𝑏, +EQ.3: switch material axes 𝑎 and 𝑐, +EQ.4: switch material axes 𝑏 and 𝑐. +IHIS +Flag for anisotropic stiffness terms initialization (for solid +elements only). +EQ.0: C11, C12, … from Cards 1, 2, and 3 are used. +EQ.1: C11, C12, … are initialized by *INITIAL_STRESS_SOL- +ID’s history data. +V1, V2, V3 +Define components of vector 𝐯 for AOPT = 3 and 4. +D1, D2, D3 +Define components of vector 𝐝 for AOPT = 2. +BETA +REF +Material angle in degrees for AOPT = 3, may be overridden on +the element card, see *ELEMENT_SHELL_BETA or *ELEMENT_- +SOLID_ORTHO. +Use reference geometry to initialize the stress tensor. The +reference geometry is defined by the keyword: *INITIAL_- +FOAM_REFERENCE_GEOMETRY . +EQ.0.0: off, +EQ.1.0: on. +Remarks: +The material law that relates stresses to strains is defined as: +𝐂 = 𝐓T𝐂𝐿𝐓 +where 𝐓 is a transformation matrix, and 𝐂𝐿 is the constitutive matrix defined in terms of +the material constants of the orthogonal material axes, {𝐚, 𝐛, 𝐜}. The inverse of 𝐂𝐿for +the orthotropic case is defined as: +−1 = +𝐂𝐿 +𝐸𝑎 +𝜐𝑎𝑏 +𝐸𝑎 +𝜐𝑎𝑐 +𝐸𝑎 +− +− +− +− +𝜐𝑏𝑎 +𝐸𝑏 +𝐸𝑏 +𝜐𝑏𝑐 +𝐸𝑏 +− +− +𝜐𝑐𝑎 +𝐸𝑐 +𝜐𝑐𝑏 +𝐸𝑐 +𝐸𝑐 +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +𝐺𝑎𝑏 +𝐺𝑏𝑐 +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +𝐺𝑐𝑎⎦ +where, +𝜐𝑎𝑏 +𝐸𝑎 += +𝜐𝑏𝑎 +𝐸𝑏 +, +𝜐𝑐𝑎 +𝐸𝑐 += +𝜐𝑎𝑐 +𝐸𝑎 +, +𝜐𝑐𝑏 +𝐸𝑐 += +𝜐𝑏𝑐 +𝐸𝑏 +. +The frequency independent damping is obtained by having a spring and slider in series +as shown in the following sketch: +friction +This option applies only to orthotropic solid elements and affects only the deviatoric +stresses. +The procedure for describing the principle material directions is now explained for +solid and shell elements for this material model and other anisotropic materials. We +will call the material coordinate system the {𝐚, 𝐛, 𝐜} coordinate system. The AOPT +options illustrated in Figure M2-1 define the preliminary {𝐚, 𝐛, 𝐜} system for all elements +of the parts that use the material, but this is not the final material direction. The {𝐚, 𝐛, 𝐜} +system defined by the AOPT options may be offset by a final rotation about the 𝐜-axis. +The offset angle we call BETA. +For solid elements, the BETA angle is specified in one of two ways. When using +AOPT = 3, the BETA parameter defines the offset angle for all elements that use the +material. The BETA parameter has no meaning for the other AOPT options. +Alternatively, a BETA angle can be defined for individual solid elements as described in +remark 5 for *ELEMENT_SOLID_ORTHO. The beta angle by the ORTHO option is +available for all values of AOPT, and it overrides the BETA angle on the *MAT card for +AOPT = 3. +The directions determined by the material AOPT options may be overridden for +individual elements as described in remark 3 for *ELEMENT_SOLID_ORTHO. +However, be aware that for materials with AOPT = 3, the final {𝐚, 𝐛, 𝐜} system will be +the system defined on the element card rotated about 𝐜-axis by the BETA angle +specified on the *MAT card. +There are two fundamental differences between shell and solid element orthotropic +materials. First, the 𝐜-direction is always normal to a shell element such that the 𝐚- +direction and 𝐛-directions are within the plane of the element. Second, for some +anisotropic materials, shell elements may have unique fiber directions within each layer +through the thickness of the element so that a layered composite can be modeled with a +single element. +When AOPT = 0 is used in two-dimensional planar and axisymmetric analysis, it is +critical that the nodes in the element definition be numbered counterclockwise for this +option to work correctly. +Because shell elements have their 𝐜-axes defined by the element normal, AOPT = 1 and +AOPT = 4 are not available for shells. Also, AOPT = 2 requires only the vector 𝐚 be +defined since 𝐝 is not used. The shell procedure projects the inputted 𝐚-direction onto +each element surface. +Similar to solid elements, the {𝐚, 𝐛, 𝐜} coordinate system determined by AOPT is then +modified by a rotation about the 𝐜-axis which we will call 𝜙. For those materials that +allow a unique rotation angle for each integration point through the element thickness, +the rotation angle is calculated by +𝜙𝑖 = 𝛽 + 𝛽𝑖 +where 𝛽 is a rotation for the element, and 𝛽𝑖 is the rotation for the i’th layer of the +element. The 𝛽 angle can be input using the BETA parameter on the *MAT data, or will +be overridden for individual elements if the BETA keyword option for *ELEMENT_- +SHELL is used. The 𝛽𝑖 angles are input using the ICOMP = 1 option of *SECTION_- +SHELL or with *PART_COMPOSITE. If 𝛽 or 𝛽𝑖 is omitted, they are assumed to be zero. +All anisotropic shell materials have the BETA parameter on the *MAT card available for +both AOPT = 0 and AOPT = 3, except for materials 91 and 92 which have it available +(but called FANG instead of BETA) for AOPT = 0, 2, and 3. +All anisotropic shell materials allow an angle for each integration point through the +thickness, 𝛽𝑖, except for materials 2, 86, 91, 92, 117, 130, 170, 172, and 194. +This discussion of material direction angles in shell elements also applies to thick shell +elements which allow modeling of layered composites using *INTEGRATION_SHELL +or *PART_COMPOSITE_TSHELL. +Illustration of AOPT: Figure M2-1 +AOPT = 0.0 +AOPT = 1.0 (solid only) +v14 +c = a×b +a = v12 +b = v14 - a a⋅v14 +a⋅a +⇒ a⋅b = 0 +ez +ey +ex +b = c x a +d ∕∕ ez +c = a x d +a is set parallel to the +line segment connecting +p to the element center. +d is set parallel to ez. +input(p) → {a} → {c} → {b} +AOPT = 2.0 (solid) +AOPT = 2.0 (shell) +c is orthogonal +to the a,d plane +c = a × d +a,d are input. +The computed +axes do not +depend on the +element. +b = c × a +b is orthogonal +to the c,a plane +a = ainput - +⋅n +ainput +n⋅n +c = n +ainput +b = c×a +AOPT = 3.0 +AOPT = 4.0 (solid only) +c = n +b = v - c +c⋅v +c⋅c +a = b×n +b is the projection of v +(from input) onto the +midplane/shell. +Taken together, point +p and vector v define +the axis of symmetry. +a = b×c +b ∕∕ v +c is parallel to the segment +connecting the element +center to the symmetry axis. +(cid:13)(cid:51)(cid:36)(cid:53)(cid:55) +(cid:66)(cid:77)(cid:84)(cid:109)(cid:105) +(cid:98)(cid:118)(cid:75)(cid:35)(cid:81)(cid:72)(cid:103)(cid:47)(cid:50)(cid:98)(cid:43) +(cid:84)(cid:66)(cid:47) +(cid:75)(cid:66)(cid:47) +(cid:99)(cid:51)(cid:106)(cid:99) (cid:66)(cid:47) (cid:56)(cid:82)(cid:97) (cid:106)(cid:64)(cid:67)(cid:99) (cid:85)(cid:29)(cid:97)(cid:106) +(cid:85)(cid:82)(cid:67)(cid:78)(cid:106)(cid:51)(cid:97) (cid:106)(cid:82) (cid:76)(cid:29)(cid:106)(cid:51)(cid:97)(cid:67)(cid:29)(cid:73) +(cid:13)(cid:40)(cid:47)(cid:40)(cid:48)(cid:40)(cid:49)(cid:55)(cid:66)(cid:54)(cid:50)(cid:47)(cid:44)(cid:39)(cid:66)(cid:94)(cid:50)(cid:51)(cid:55)(cid:44)(cid:50)(cid:49)(cid:96) +(cid:66)(cid:77)(cid:84)(cid:109)(cid:105) +(cid:98)(cid:118)(cid:75)(cid:35)(cid:81)(cid:72)(cid:103)(cid:47)(cid:50)(cid:98)(cid:43) +(cid:84)(cid:66)(cid:47) +(cid:35)(cid:50)(cid:105)(cid:28)(cid:103)(cid:28)(cid:83) +(cid:86)(cid:28)(cid:83)(cid:87)(cid:46) (cid:28)(cid:108)(cid:46) (cid:28)(cid:107) +(cid:47)(cid:83)(cid:46) (cid:47)(cid:108)(cid:46) (cid:47)(cid:107) +(cid:85)(cid:82)(cid:67)(cid:78)(cid:106)(cid:51)(cid:97) (cid:106)(cid:82) (cid:85)(cid:29)(cid:97)(cid:106) +(cid:1804)(cid:1397)(cid:46) (cid:48)(cid:51)(cid:56)(cid:29)(cid:110)(cid:73)(cid:106)(cid:99) (cid:106)(cid:82) (cid:122) +(cid:531)(cid:1397)(cid:46) (cid:82)(cid:85)(cid:106)(cid:67)(cid:82)(cid:78)(cid:29)(cid:73) +(cid:534)(cid:1397)(cid:46) (cid:82)(cid:85)(cid:106)(cid:67)(cid:82)(cid:78)(cid:29)(cid:73) +(cid:105)(cid:64)(cid:51)(cid:78) (cid:73)(cid:51)(cid:106) +(cid:531) (cid:30) (cid:531)(cid:1397) +(cid:533) (cid:30) (cid:531)(cid:1397) (cid:3701) (cid:534)(cid:1397) +(cid:532) (cid:30) (cid:533)(cid:1397) (cid:3701) (cid:531)(cid:1397)(cid:15) +(cid:1804)(cid:1397) (cid:67)(cid:99) (cid:78)(cid:82)(cid:106) (cid:48)(cid:51)(cid:126)(cid:78)(cid:51)(cid:48)(cid:89) +(cid:47)(cid:82)(cid:51)(cid:99) (cid:106)(cid:64)(cid:67)(cid:99) +(cid:51)(cid:73)(cid:51)(cid:76)(cid:51)(cid:78)(cid:106) (cid:64)(cid:29)(cid:113)(cid:51) +(cid:531)(cid:1397) (cid:29)(cid:78)(cid:48) (cid:534)(cid:1397)(cid:93) +(cid:119)(cid:51)(cid:99) +(cid:78)(cid:82) +(cid:43)(cid:29)(cid:73)(cid:44)(cid:110)(cid:73)(cid:29)(cid:106)(cid:51) (cid:531)(cid:46) (cid:532)(cid:46) (cid:29)(cid:78)(cid:48) (cid:533) (cid:56)(cid:97)(cid:82)(cid:76) +(cid:544)(cid:1429)(cid:46) (cid:531)(cid:1429)(cid:46) (cid:550)(cid:1429)(cid:46) (cid:29)(cid:78)(cid:48) (cid:534)(cid:1429) (cid:29)(cid:44)(cid:65) +(cid:44)(cid:82)(cid:97)(cid:48)(cid:67)(cid:78)(cid:60) (cid:106)(cid:82) (cid:28)(cid:81)(cid:84)(cid:105) (cid:86)(cid:99)(cid:51)(cid:51) +(cid:28)(cid:81)(cid:84)(cid:105) (cid:126)(cid:60)(cid:110)(cid:97)(cid:51)(cid:87)(cid:89) +(cid:13)(cid:48)(cid:36)(cid:55) +(cid:66)(cid:77)(cid:84)(cid:109)(cid:105) +(cid:98)(cid:118)(cid:75)(cid:35)(cid:81)(cid:72)(cid:103)(cid:47)(cid:50)(cid:98)(cid:43) +(cid:99)(cid:51)(cid:106) (cid:66)(cid:47) (cid:56)(cid:82)(cid:97) (cid:106)(cid:64)(cid:67)(cid:99) (cid:76)(cid:29)(cid:106)(cid:51)(cid:97)(cid:67)(cid:29)(cid:73) +(cid:29)(cid:117)(cid:51)(cid:99) (cid:29)(cid:73)(cid:60)(cid:82)(cid:97)(cid:67)(cid:106)(cid:64)(cid:76) (cid:127)(cid:29)(cid:60) +(cid:29)(cid:117)(cid:51)(cid:99) (cid:44)(cid:64)(cid:29)(cid:78)(cid:60)(cid:51) (cid:127)(cid:29)(cid:60) +(cid:544)(cid:1429) +(cid:531)(cid:1429) +(cid:550)(cid:1429) +(cid:534)(cid:1429) +(cid:1804)(cid:1429)(cid:46) (cid:48)(cid:51)(cid:56)(cid:29)(cid:110)(cid:73)(cid:106)(cid:99) (cid:106)(cid:82) (cid:122) +(cid:75)(cid:66)(cid:47) +(cid:28)(cid:81)(cid:84)(cid:105) +(cid:75)(cid:28)(cid:43)(cid:55) +(cid:116)(cid:84)(cid:46) (cid:118)(cid:84)(cid:46) (cid:120)(cid:84) +(cid:28)(cid:83)(cid:46) (cid:28)(cid:108)(cid:46) (cid:28)(cid:107) +(cid:112)(cid:83)(cid:46) (cid:112)(cid:108)(cid:46) (cid:112)(cid:107) +(cid:47)(cid:83)(cid:46) (cid:47)(cid:108)(cid:46) (cid:47)(cid:107) +(cid:35)(cid:50)(cid:105)(cid:28) +(cid:119)(cid:51)(cid:99) +(cid:34)(cid:48)(cid:49)(cid:53) (cid:30) (cid:20)(cid:93) +(cid:78)(cid:82) +(cid:96)(cid:82)(cid:106)(cid:29)(cid:106)(cid:51) (cid:531) (cid:29)(cid:78)(cid:48) (cid:532) +(cid:36)(cid:119) (cid:1804)(cid:1429) (cid:29)(cid:36)(cid:82)(cid:110)(cid:106) (cid:533)(cid:89) +(cid:78)(cid:82) +(cid:96)(cid:82)(cid:106)(cid:29)(cid:106)(cid:51) (cid:531) (cid:29)(cid:78)(cid:48) (cid:532) +(cid:36)(cid:119) (cid:1804)(cid:1397) (cid:29)(cid:36)(cid:82)(cid:110)(cid:106) (cid:533)(cid:89) +(cid:1804)(cid:1397) (cid:48)(cid:51)(cid:126)(cid:78)(cid:51)(cid:48)(cid:93) +(cid:119)(cid:51)(cid:99) +(cid:28)(cid:85)(cid:85)(cid:73)(cid:119) (cid:75)(cid:28)(cid:43)(cid:55)(cid:89) +(cid:96)(cid:51)(cid:106)(cid:110)(cid:97)(cid:78) (cid:531)(cid:46) +(cid:532)(cid:46) (cid:29)(cid:78)(cid:48) (cid:533)(cid:89) +(cid:105)(cid:67)(cid:76)(cid:51) (cid:51)(cid:113)(cid:82)(cid:73)(cid:113)(cid:51) (cid:531)(cid:46) (cid:532)(cid:46) (cid:29)(cid:78)(cid:48) +(cid:533) (cid:115)(cid:67)(cid:106)(cid:64) (cid:106)(cid:64)(cid:51) (cid:51)(cid:73)(cid:51)(cid:76)(cid:51)(cid:78)(cid:106)(cid:89) +Figure M2-2. Flow chart showing how for each solid element LS-DYNA +determines the vectors {𝒂, 𝒃, 𝒄} from the input. +(cid:13)(cid:54)(cid:40)(cid:38)(cid:55)(cid:44)(cid:50)(cid:49)(cid:66)(cid:54)(cid:43)(cid:40)(cid:47)(cid:47) +(cid:13)(cid:48)(cid:36)(cid:55) +(cid:66)(cid:77)(cid:84)(cid:109)(cid:105) +(cid:98)(cid:118)(cid:75)(cid:35)(cid:81)(cid:72)(cid:103)(cid:47)(cid:50)(cid:98)(cid:43) +(cid:98)(cid:50)(cid:43)(cid:66)(cid:47) (cid:99)(cid:51)(cid:106)(cid:99) (cid:99)(cid:51)(cid:44)(cid:106)(cid:67)(cid:82)(cid:78) (cid:66)(cid:47) +(cid:66)(cid:43)(cid:81)(cid:75)(cid:84) +(cid:98)(cid:98)(cid:35)(cid:83)(cid:46) (cid:98)(cid:98)(cid:35)(cid:108)(cid:46) (cid:15)(cid:15)(cid:15) +(cid:127)(cid:29)(cid:60)(cid:46) (cid:67)(cid:56) (cid:83) (cid:97)(cid:51)(cid:29)(cid:48) (cid:1804)(cid:1413) +(cid:29)(cid:78)(cid:60)(cid:73)(cid:51)(cid:99)(cid:45) (cid:1804)(cid:1413)(cid:46) +(cid:13)(cid:51)(cid:36)(cid:53)(cid:55) +(cid:66)(cid:77)(cid:84)(cid:109)(cid:105) +(cid:98)(cid:118)(cid:75)(cid:35)(cid:81)(cid:72)(cid:103)(cid:47)(cid:50)(cid:98)(cid:43) +(cid:84)(cid:66)(cid:47) (cid:99)(cid:51)(cid:106) (cid:85)(cid:29)(cid:97)(cid:106) (cid:66)(cid:47) +(cid:75)(cid:66)(cid:47) (cid:85)(cid:82)(cid:67)(cid:78)(cid:106)(cid:51)(cid:97) (cid:106)(cid:82) (cid:76)(cid:29)(cid:106)(cid:51)(cid:97)(cid:67)(cid:29)(cid:73) +(cid:98)(cid:50)(cid:43)(cid:66)(cid:47) (cid:85)(cid:82)(cid:67)(cid:78)(cid:106)(cid:51)(cid:97) (cid:106)(cid:82) (cid:99)(cid:51)(cid:44)(cid:106)(cid:67)(cid:82)(cid:78) +(cid:13)(cid:40)(cid:47)(cid:40)(cid:48)(cid:40)(cid:49)(cid:55)(cid:66)(cid:54)(cid:43)(cid:40)(cid:47)(cid:47)(cid:66)(cid:94)(cid:50)(cid:51)(cid:55)(cid:44)(cid:50)(cid:49)(cid:96) +(cid:66)(cid:77)(cid:84)(cid:109)(cid:105) +(cid:98)(cid:118)(cid:75)(cid:35)(cid:81)(cid:72)(cid:103)(cid:47)(cid:50)(cid:98)(cid:43) +(cid:84)(cid:66)(cid:47) (cid:85)(cid:82)(cid:67)(cid:78)(cid:106)(cid:51)(cid:97) (cid:106)(cid:82) (cid:85)(cid:29)(cid:97)(cid:106) +(cid:75)(cid:43)(cid:66)(cid:47) (cid:85)(cid:82)(cid:67)(cid:78)(cid:106)(cid:51)(cid:97) (cid:106)(cid:82) (cid:44)(cid:82)(cid:82)(cid:97)(cid:48)(cid:67)(cid:78)(cid:29)(cid:106)(cid:51) (cid:99)(cid:119)(cid:99)(cid:106)(cid:51)(cid:76) +(cid:35)(cid:50)(cid:105)(cid:28) (cid:1804)(cid:1397)(cid:46) (cid:48)(cid:51)(cid:56)(cid:29)(cid:110)(cid:73)(cid:106)(cid:99) (cid:106)(cid:82) (cid:122) +(cid:66)(cid:77)(cid:84)(cid:109)(cid:105) +(cid:98)(cid:118)(cid:75)(cid:35)(cid:81)(cid:72)(cid:103)(cid:47)(cid:50)(cid:98)(cid:43) +(cid:75)(cid:66)(cid:47) (cid:99)(cid:51)(cid:106)(cid:99) (cid:76)(cid:29)(cid:106)(cid:51)(cid:97)(cid:67)(cid:29)(cid:73) (cid:66)(cid:47) +(cid:28)(cid:81)(cid:84)(cid:105) +(cid:28)(cid:83)(cid:46) (cid:28)(cid:108)(cid:46) (cid:28)(cid:107) +(cid:112)(cid:83)(cid:46) (cid:112)(cid:108)(cid:46) (cid:112)(cid:107) +(cid:29)(cid:117)(cid:51)(cid:99) (cid:29)(cid:73)(cid:60)(cid:82)(cid:97)(cid:67)(cid:106)(cid:64)(cid:76) (cid:127)(cid:29)(cid:60) 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(cid:1804)(cid:1413) +(cid:11)(cid:36)(cid:12) +(cid:119)(cid:51)(cid:99) +(cid:66)(cid:99) (cid:75)(cid:43)(cid:66)(cid:47) +(cid:48)(cid:51)(cid:126)(cid:78)(cid:51)(cid:48)(cid:93) +(cid:78)(cid:82) +(cid:98)(cid:51)(cid:106) (cid:531)(cid:46) (cid:532)(cid:46) (cid:29)(cid:78)(cid:48) +(cid:533) (cid:56)(cid:97)(cid:82)(cid:76) (cid:44)(cid:82)(cid:82)(cid:97)(cid:65) +(cid:48)(cid:67)(cid:78)(cid:29)(cid:106)(cid:51) (cid:99)(cid:119)(cid:99)(cid:106)(cid:51)(cid:76) +(cid:75)(cid:43)(cid:66)(cid:47)(cid:89) +(cid:66)(cid:99) (cid:84)(cid:66)(cid:47) (cid:29) +(cid:44)(cid:82)(cid:76)(cid:85)(cid:82)(cid:99)(cid:67)(cid:106)(cid:51)(cid:93) +(cid:11)(cid:37)(cid:12) +(cid:11)(cid:38)(cid:12) +(cid:119)(cid:51)(cid:99) +(cid:77) (cid:53) (cid:83) +(cid:75) (cid:53) (cid:75)(cid:66)(cid:47)(cid:77) +(cid:86)(cid:56)(cid:97)(cid:82)(cid:76) (cid:44)(cid:82)(cid:76)(cid:85)(cid:82)(cid:99)(cid:67)(cid:106)(cid:51)(cid:87) +(cid:77) (cid:2957) (cid:77) (cid:90) (cid:83) +(cid:78)(cid:82) +(cid:75) (cid:53) (cid:75)(cid:66)(cid:47) +(cid:86)(cid:56)(cid:97)(cid:82)(cid:76) (cid:84)(cid:28)(cid:96)(cid:105)(cid:87) +(cid:78)(cid:82) +(cid:43)(cid:29)(cid:73)(cid:44)(cid:110)(cid:73)(cid:29)(cid:106)(cid:51) (cid:531)(cid:46) (cid:532)(cid:46) (cid:29)(cid:78)(cid:48) (cid:533) (cid:56)(cid:97)(cid:82)(cid:76) (cid:531)(cid:1429) +(cid:29)(cid:78)(cid:48) (cid:550)(cid:1429) (cid:29)(cid:44)(cid:44)(cid:82)(cid:97)(cid:48)(cid:67)(cid:78)(cid:60) (cid:106)(cid:82) (cid:28)(cid:81)(cid:84)(cid:105) (cid:56)(cid:82)(cid:97) +(cid:76)(cid:29)(cid:106)(cid:51)(cid:97)(cid:67)(cid:29)(cid:73) (cid:75) (cid:86)(cid:99)(cid:51)(cid:51) (cid:28)(cid:81)(cid:84)(cid:105) (cid:126)(cid:60)(cid:110)(cid:97)(cid:51)(cid:87)(cid:89) +(cid:66)(cid:99) (cid:76)(cid:29)(cid:106)(cid:51)(cid:97)(cid:67)(cid:29)(cid:73) (cid:75) +(cid:29)(cid:78)(cid:67)(cid:99)(cid:82)(cid:106)(cid:97)(cid:82)(cid:85)(cid:67)(cid:44)(cid:93) +(cid:119)(cid:51)(cid:99) +(cid:28)(cid:81)(cid:84)(cid:105) (cid:67)(cid:99) +(cid:51)(cid:67)(cid:106)(cid:64)(cid:51)(cid:97) (cid:122) (cid:82)(cid:97) (cid:107)(cid:93) +(cid:119)(cid:51)(cid:99) +(cid:1804)(cid:1397) (cid:48)(cid:51)(cid:126)(cid:78)(cid:51)(cid:48)(cid:93) +(cid:119)(cid:51)(cid:99) +(cid:1804) (cid:53) (cid:1804)(cid:1397) +(cid:1804) (cid:53) (cid:1804)(cid:1429) +(cid:78)(cid:82) +(cid:96)(cid:82)(cid:106)(cid:29)(cid:106)(cid:51) (cid:531) (cid:29)(cid:78)(cid:48) +(cid:532) (cid:36)(cid:119) (cid:1804) (cid:29)(cid:36)(cid:82)(cid:110)(cid:106) +(cid:533)(cid:89) +(cid:78)(cid:82) +(cid:72)(cid:51)(cid:106) (cid:1804)(cid:1429) (cid:30) (cid:17) +(cid:11)(cid:39)(cid:12) +(cid:98)(cid:51)(cid:106) (cid:29)(cid:73)(cid:73) +(cid:92)(cid:1804)(cid:94)(cid:1413) (cid:30) (cid:17) +(cid:92)(cid:1804)(cid:1413)(cid:94) (cid:30) (cid:92)(cid:458)(cid:445)(cid:444)(cid:451)(cid:94) +(cid:92)(cid:1804)(cid:1413)(cid:94) (cid:30) (cid:92)(cid:461)(cid:461)(cid:444)(cid:451)(cid:94) +(cid:119)(cid:51)(cid:99) +(cid:119)(cid:51)(cid:99) +(cid:66)(cid:99) (cid:84)(cid:66)(cid:47) (cid:29) +(cid:44)(cid:82)(cid:76)(cid:85)(cid:82)(cid:99)(cid:67)(cid:106)(cid:51)(cid:93) +(cid:78)(cid:82) +(cid:66)(cid:43)(cid:81)(cid:75)(cid:84) (cid:53) (cid:83)(cid:93) +(cid:78)(cid:82) +(cid:105)(cid:67)(cid:76)(cid:51) (cid:51)(cid:113)(cid:82)(cid:73)(cid:113)(cid:51) (cid:531)(cid:46) +(cid:532)(cid:46) (cid:533)(cid:46) (cid:29)(cid:78)(cid:48) (cid:92)(cid:1804)(cid:1413)(cid:94)(cid:89) +(cid:96)(cid:51)(cid:106)(cid:110)(cid:97)(cid:78) (cid:531)(cid:46) (cid:532)(cid:46) +(cid:533)(cid:46) (cid:29)(cid:78)(cid:48) (cid:92)(cid:1804)(cid:1413)(cid:94)(cid:89) +Figure M2-3. Flowchart for shells: (a) check for coordinate system ID; (b) +process AOPT; (c) deterimine 𝛽; and (d) for each layer determine 𝛽𝑖. +*MAT_003 +This is Material Type 3. This model is suited to model isotropic and kinematic +hardening plasticity with the option of including rate effects. It is a very cost effective +model and is available for beam (Hughes-Liu and Truss), shell, and solid elements. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +6 +7 +8 +SIGY +ETAN +BETA +F +F +F +Default +none +none +none +none +none +0.0 +0.0 +5 +6 +7 +8 + Card 2 +1 +2 +Variable +SRC +SRP +Type +F +F +3 +FS +F +4 +VP +F +Default +0.0 +0.0 +1.E+20 +0.0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +SIGY +ETAN +BETA +SRC +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +Yield stress. +Tangent modulus, see Figure M3-1 +Hardening parameter, 0 < 𝛽′ < 1. See comments below. +Strain rate parameter, C, for Cowper Symonds strain rate model, +see below. If zero, rate effects are not considered.. +Et +Yield +Stress +⎛ +⎜ +⎝ +⎛ +⎜ +⎝ +l0 +ln +β=0, kinematic hardening +β=1, isotropic hardening +Figure M3-1. Elastic-plastic behavior with kinematic and isotropic hardening +where 𝑙0 and 𝑙 are undeformed and deformed lengths of uniaxial tension +specimen. 𝐸𝑡 is the slope of the bilinear stress strain curve. + VARIABLE +DESCRIPTION +Strain rate parameter, P, for Cowper Symonds strain rate model, +see below. If zero, rate effects are not considered. +Effective plastic strain for eroding elements. +Formulation for rate effects: +EQ.0.0: Scale yield stress (default), +EQ.1.0: Viscoplastic formulation (recommended) +SRP +FS +VP +Remarks: +Strain rate is accounted for using the Cowper and Symonds model which scales the +yield stress with the factor +1 + ( +𝜀̇ +𝑝⁄ +) +where 𝜀̇ is the strain rate. A fully viscoplastic formulation is optional which +incorporates the Cowper and Symonds formulation within the yield surface. To ignore +strain rate effects set both SRC and SRP to zero. +Kinematic, isotropic, or a combination of kinematic and isotropic hardening may be +specified by varying 𝛽′ between 0 and 1. For 𝛽′ equal to 0 and 1, respectively, kinematic +and isotropic hardening are obtained as shown in Figure M3-1. For isotropic +hardening, 𝛽′= 1, Material Model 12, *MAT_ISOTROPIC_ELASTIC_PLASTIC, requires +less storage and is more efficient. Whenever possible, Material 12 is recommended for +solid elements, but for shell elements it is less accurate and thus Material 12 is not +recommended in this case. +*MAT_ELASTIC_PLASTIC_THERMAL +This is Material Type 4. Temperature dependent material coefficients can be defined. +A maximum of eight temperatures with the corresponding data can be defined. A +minimum of two points is needed. When this material type is used it is necessary to +define nodal temperatures by activating a coupled analysis or by using another option +to define the temperatures such as *LOAD_THERMAL_LOAD_CURVE, or *LOAD_- +THERMAL_VARIABLE. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F + Card 2 +Variable +1 +T1 +Type +F + Card 3 +Variable +1 +E1 +Type +F + Card 4 +1 +2 +T2 +F +2 +E2 +F +2 +3 +4 +5 +6 +7 +8 +3 +T3 +F +3 +E3 +F +3 +4 +T4 +F +4 +E4 +F +4 +5 +T5 +F +5 +E5 +F +5 +6 +T6 +F +6 +E6 +F +6 +7 +T7 +F +7 +E7 +F +7 +8 +T8 +F +8 +E8 +F +8 +Variable +PR1 +PR2 +PR3 +PR4 +PR5 +PR6 +PR7 +PR8 +Type +F +F +F +F +F +F +F +No defaults are assumed. + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ALPHA1 +ALPHA2 +ALPHA3 +ALPHA4 +ALPHA5 +ALPHA6 +ALPHA7 +ALPHA8 +Type +F + Card 6 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +SIGY1 +SIGY2 +SIGY3 +SIGY4 +SIGY5 +SIGY6 +SIGY7 +SIGY8 +Type +F + Card 7 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +ETAN1 +ETAN2 +ETAN3 +ETAN4 +ETAN5 +ETAN6 +ETAN7 +ETAN8 +Type +F +F +F +F +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +TI +EI +PRI +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Temperatures. The minimum is 2, the maximum is 8. +Corresponding Young’s moduli at temperature TI. +Corresponding Poisson’s ratios. +ALPHAI +Corresponding coefficients of thermal expansion. +SIGYI +Corresponding yield stresses. +ETANI +Corresponding plastic hardening moduli. +*MAT_ELASTIC_PLASTIC_THERMAL +The stress update for this material follows the standard approach to hypo- +elastoplasticity, using Jaumann rate for objectivity. The rate of Cauchy stress 𝝈 can in +principal be expressed as +𝝈̇ = 𝑪(𝜺̇ − 𝜺̇𝑇 − 𝜺̇𝑝) + 𝑪̇𝑪−1𝝈 +where 𝑪 is the temperature dependent isotropic elasticity tensor, 𝜺̇ is the rate-of- +deformation, 𝜺̇𝑇 is the thermal strain rate and 𝜺̇𝑝 is the plastic strain rate. The coefficient +of thermal expansion is defined as the instantaneous value. Thus, the thermal strain +rate becomes +𝜺̇𝑇 = 𝛼𝑇̇𝑰 +where 𝛼 is the temperature dependent thermal expansion coefficient, 𝑇̇ is the rate of +temperature and 𝑰 is the identity tensor. Associated von Mises plasticity is adopted, +resulting in +𝜺̇𝑝 = 𝜀̇𝑝 +3𝒔 +2𝜎̅̅̅̅̅ +where 𝜀̇𝑝 is the effective plastic strain rate, 𝒔 is the deviatoric stress tensor and 𝜎̅̅̅̅̅ is the +von Mises effective stress. The last term accounts for stress changes due to change in +stiffness with respect to temperature, using the total elastic strain defined as 𝜺𝑒 = 𝑪−1𝝈. +A way to intuitively understand this contribution, for small displacement elasticity if +neglecting everything but the temperature dependent elasticity parameters, we have +𝝈̇ = +𝑑𝑡 +(𝑪𝜺) +as a special case, showing that the stress may change without any change in strain. +At least two temperatures and their corresponding material properties must be defined. +The analysis will be terminated if a material temperature falls outside the range defined +in the input. If a thermo-elastic material is considered, do not define SIGY and ETAN. +*MAT_005 +This is Material Type 5. It is a relatively simple material model for representing soil, +concrete, or crushable foam. A table can be defined if thermal effects are considered in +the pressure versus volumetric strain behavior. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +G +F +3 +4 +KUN +F +4 +5 +A0 +F +5 +6 +A1 +F +6 +7 +A2 +F +7 +8 +PC +F +8 +Variable +VCR +REF +LCID +Type +F + Card 3 +1 +F +2 +F +3 +4 +5 +6 +7 +8 +Variable +EPS1 +EPS2 +EPS3 +EPS4 +EPS5 +EPS6 +EPS7 +EPS8 +Type +F + Card 4 +1 +F +2 +Variable +EPS9 +EPS10 +Type +F +F + Card 5 +Variable +1 +P1 +Type +F +2 +P2 +F +F +3 +3 +P3 +F +F +4 +4 +P4 +F +F +5 +5 +P5 +F +F +6 +6 +P6 +F +F +7 +7 +P7 +F +F +8 +8 +P8 +4 +5 +6 +7 +8 +*MAT_005 + Card 6 +Variable +1 +P9 +2 +P10 +Type +F +F + VARIABLE +DESCRIPTION +MID +RO +G +Material identification. A unique number or label not exceeding +8 characters must be specified. +Mass density. +Shear modulus. +KUN +Bulk modulus for unloading used for VCR = 0.0. +A0 +A1 +A2 +PC +Yield function constant for plastic yield function below. +Yield function constant for plastic yield function below. +Yield function constant for plastic yield function below. +Pressure cutoff for tensile fracture (< 0). +VCR +Volumetric crushing option: +EQ.0.0: on, +EQ.1.0: loading and unloading paths are the same. +REF +Use reference geometry to initialize the pressure. The reference +geometry is defined by the keyword:*INITIAL_FOAM_REFER- +ENCE_GEOMETRY. +the +deviatoric stress state. + This option does not +initialize +EQ.0.0: off, +EQ.1.0: on. +VARIABLE +LCID +EPS1, … +DESCRIPTION +Load curve ID for compressive pressure (ordinate) as a function +of volumetric strain (abscissa). If LCID is defined, then the curve +is used instead of the input for EPS1…, and P1…. It makes no +difference whether the values of volumetric strain in the curve +are input as positive or negative since internally, a negative sign +is applied to the absolute value of each abscissa entry. The +response is extended to being temperature dependent if LCID +refers to a table. +Volumetric strain values in pressure vs. volumetric strain curve +. A maximum of 10 values including 0.0 are +allowed and a minimum of 2 values are necessary. If EPS1 is not +0.0 then a point (0.0, 0.0) will be automatically generated and a +maximum of nine values may be input. +P1, P2, …, PN +Pressures corresponding to volumetric strain values given on +Cards 3 and 4. +Loading and unloading (along the grey +arows) follows the input curve when the +volumetric crushing option is off (VCR = 1.0) +tension +Pressure Cutoff Value +compression +Volumetric Strain, +ln +⎛ +⎜ +⎝ +⎛ +⎜ +⎝ +V0 +The bulk unloading modulus is used +if the volumetric crushing option is on +(VCR = 0). In thiscase the aterial's response +follows the black arrows. +Figure M5-1. Pressure versus volumetric strain curve for soil and crushable +foam model. The volumetric strain is given by the natural logarithm of the +relative volume, 𝑉. +Remarks: +Pressure is positive in compression. Volumetric strain is given by the natural log of the +relative volume and is negative in compression. Relative volume is a ratio of the +current volume to the initial volume at the start of the calculation. The tabulated data +should be given in order of increasing compression. If the pressure drops below the +cutoff value specified, it is reset to that value. For a detailed description we refer to +Kreig [1972]. +The deviatoric perfectly plastic yield function, 𝜙, is described in terms of the second +invariant 𝐽2, +𝐽2 = + 𝑠𝑖𝑗𝑠𝑖𝑗, +pressure, 𝑝, and constants 𝑎0, 𝑎1, and 𝑎2 as: +𝜙 = 𝐽2 − [𝑎0 + 𝑎1𝑝 + 𝑎2𝑝2]. +On the yield surface 𝐽2 = 1 +3 𝜎𝑦 +2 where 𝜎𝑦 is the uniaxial yield stress, i.e., +there is no strain hardening on this surface. +𝜎𝑦 = [3(𝑎0 + 𝑎1𝑝 + 𝑎2𝑝2)] +2⁄ +To eliminate the pressure dependence of the yield strength, set: +𝑎1 = 𝑎2 = 0 and 𝑎0 = +2. +𝜎𝑦 +This approach is useful when a von Mises type elastic-plastic model is desired for use +with the tabulated volumetric data. +The history variable labeled as “plastic strain” by LS-PrePost is actually plastic +volumetric strain. Note that when VCR = 1.0, plastic volumetric strain is zero. +*MAT_VISCOELASTIC +This is Material Type 6. This model allows the modeling of viscoelastic behavior for +beams (Hughes-Liu), shells, and solids. Also see *MAT_GENERAL_VISCOELASTIC +for a more general formulation. + Card 1 +1 +Variable +MID +2 +RO +3 +BULK +Type +A8 +F +F +6 +7 +8 +BETA +F +4 +G0 +F +5 +GI +F +DESCRIPTION + VARIABLE +MID +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +BULK +Elastic bulk modulus. +LT.0.0: |BULK| is load curve of bulk modulus as a function of +temperature. +G0 +Short-time shear modulus, see equations below. +LT.0.0: |G0| is load curve of short-time shear modulus as a +function of temperature. +GI +Long-time (infinite) shear modulus, G∞. +LT.0.0: |GI| is load curve of long-time shear modulus as a +function of temperature. +BETA +Decay constant. +LT.0.0: |BETA| is load curve of decay constant as a function of +temperature. +Remarks: +The shear relaxation behavior is described by [Hermann and Peterson, 1968]: +A Jaumann rate formulation is used +𝐺(𝑡) = 𝐺∞ + (𝐺0 − 𝐺∞)exp (−𝛽𝑡) +∇ +′ = 2 ∫ 𝐺(𝑡 − 𝜏)𝐷′𝑖𝑗(𝜏)𝑑𝜏 +ij +∇ +𝑖𝑗, and the strain rate, D𝑖𝑗. +where the prime denotes the deviatoric part of the stress rate, 𝜎 +*MAT_BLATZ-KO_RUBBER +This is Material Type 7. This one parameter material allows the modeling of nearly +incompressible continuum rubber. The Poisson’s ratio is fixed to 0.463. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +G +F +4 +REF +F +5 +6 +7 +8 + VARIABLE +DESCRIPTION +MID +RO +G +REF +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Shear modulus. +Use reference geometry to initialize the stress tensor. The +reference geometry is defined by the keyword:*INITIAL_FOAM_- +REFERENCE_GEOMETRY . +EQ.0.0: off, +EQ.1.0: on. +Remarks: +The strain energy density potential for the Blatz-Ko rubber is +𝑊(𝐂) = +[𝐼1 − 3 + +−𝛽 − 1)] +(𝐼3 +where 𝐺 is the shear modulus, 𝐼1 and 𝐼3 are the first and third invariants of the right +Cauchy-Green tensor 𝐂 = 𝐅T𝐅 and +1 − 2𝑣 +The second Piola-Kirchhoff stress is computed as +𝛽 = +. +𝐒 = 2 +𝜕𝑊 +𝜕𝐂 += 𝐺[𝐈 − 𝐼3 +−𝛽𝐂−1] +from which the Cauchy stress is obtained by a push-forward from the reference to +current configuration divided by the relative volume 𝐽 = det(𝑭), +𝛔 = +𝐅𝐒𝐅T = +[𝐁 − 𝐼3 +−𝛽𝐈]. +Here we used 𝐁 = 𝐅𝐅T to denote the left Cauchy-Green tensor, and the Poisson ratio 𝑣 +above is set internally to 𝑣 = 0.463, also see Blatz and Ko [1962]. +*MAT_HIGH_EXPLOSIVE_BURN +This is Material Type 8. It allows the modeling of the detonation of a high explosive. In +addition an equation of state must be defined. See Wilkins [1969] and Giroux [1973]. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +D +F +4 +5 +PCJ +BETA +F +F +6 +K +F +7 +G +F +8 +SIGY +F + VARIABLE +DESCRIPTION +MID +RO +D +PCJ +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Detonation velocity. +Chapman-Jouget pressure. +BETA +Beta burn flag, BETA : +EQ.0.0: beta and programmed burn, +EQ.1.0: beta burn only, +EQ.2.0: programmed burn only. +K +G +Bulk modulus (BETA = 2.0 only). +Shear modulus (BETA = 2.0 only). +SIGY +𝜎y, yield stress (BETA = 2.0 only). +Remarks: +Burn fractions, 𝐹, which multiply the equations of states for high explosives, control the +release of chemical energy for simulating detonations. At any time, the pressure in a +high explosive element is given by: +where 𝑝eos, is the pressure from the equation of state (either types 2, 3, or 14), V is the +relative volume, and E is the internal energy density per unit initial volume. +𝑝 = 𝐹𝑝eos(𝑉, 𝐸) +In the initialization phase, a lighting time tl is computed for each element by dividing +the distance from the detonation point to the center of the element by the detonation +velocity D. If multiple detonation points are defined, the closest detonation point +determines tl. The burn fraction 𝐹 is taken as the maximum +Where +𝐹 = max(𝐹1, 𝐹2) +𝐹1 = +⎧2 (𝑡 − 𝑡𝑙)𝐷𝐴𝑒max +{ +3𝑣𝑒 +⎨ +{ + 0 +⎩ +if 𝑡 > 𝑡𝑙 +if 𝑡 ≤ 𝑡𝑙 +𝐹2 = 𝛽 = +1 − 𝑉 +1 − 𝑉𝐶𝐽 +where 𝑉𝐶𝐽 is the Chapman-Jouguet relative volume and t is current time. If 𝐹 exceeds 1, +it is reset to 1. This calculation of the burn fraction usually requires several time steps +for 𝐹 to reach unity, thereby spreading the burn front over several elements. After +reaching unity, 𝐹 is held constant. This burn fraction calculation is based on work by +Wilkins [1964] and is also discussed by Giroux [1973]. +If the beta burn option is used, BETA = 1.0, any volumetric compression will cause +detonation and +and 𝐹1 is not computed. +𝐹 = 𝐹2 +If programmed burn is used, BETA = 2.0, the undetonated high explosive material will +behave as an elastic perfectly plastic material if the bulk modulus, shear modulus, and +yield stress are defined. Therefore, with this option the explosive material can +compress without causing detonation. The location and time of detonation is controlled +by *INITIAL_DETONATION. +As an option, the high explosive material can behave as an elastic perfectly-plastic solid +prior to detonation. In this case we update the stress tensor, to an elastic trial stress, +∗ 𝑠𝑖𝑗 +𝑛+1, +∗ 𝑠𝑖𝑗 +𝑛+1 = 𝑠𝑖𝑗 +𝑛 + 𝑠𝑖𝑝𝛺𝑝𝑗 + 𝑠𝑗𝑝𝛺𝑝𝑖 + 2𝐺𝜀′̇ +𝑖𝑗𝑑𝑡 +where 𝐺 is the shear modulus, and 𝜀′̇ +condition is given by: +𝑖𝑗 is the deviatoric strain rate. The von Mises yield +𝜙 = 𝐽2 − +𝜎𝑦 +where the second stress invariant, 𝐽2, is defined in terms of the deviatoric stress +components as +and the yield stress is 𝜎𝑦. If yielding has occurred, i.e., 𝜑 > 0, the deviatoric trial stress +is scaled to obtain the final deviatoric stress at time n+1: +𝑠𝑖𝑗𝑠𝑖𝑗 +𝐽2 = +If 𝜑 ≤ 0, then +𝑛+1 = +𝑠𝑖𝑗 +𝜎𝑦 +√3𝐽2 +∗ 𝑠𝑖𝑗 +𝑛+1 +𝑛+1 =∗ 𝑠𝑖𝑗 +𝑠𝑖𝑗 +𝑛+1 +Before detonation pressure is given by the expression +𝑝𝑛+1 = Κ ( +𝑉𝑛+1 − 1) +where K is the bulk modulus. Once the explosive material detonates: +and the material behaves like a gas. +𝑛+1 = 0 +𝑠𝑖𝑗 +This is Material Type 9. +*MAT_009 +In the case of solids and thick shells, this material allows equations of state to be +considered without computing deviatoric stresses. Optionally, a viscosity can be +defined. Also, erosion in tension and compression is possible. +Beams and shells that use this material type are completely bypassed in the element +processing; however, the mass of the null beam or shell elements is computed and +added to the nodal points which define the connectivity. The mass of null beams is +ignored if the value of the density is less than 1.e-11. The Young’s modulus and +Poisson’s ratio are used only for setting the contact stiffness, and it is recommended that +reasonable values be input. The variables PC, MU, TEROD, and EDROD do not apply +to beams and shells. Historically, null beams and/or null shells have been used as an +aid in modeling of contact but this practice is now seldom needed. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +PC +F +4 +5 +6 +7 +MU +TEROD +CEROD +YM +F +F +F +F +8 +PR +F +Defaults +none +none +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +MID +RO +PC +MU +TEROD +CEROD +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Pressure cutoff (≤ 0.0). See Remark 4. +Dynamic viscosity μ (optional). See Remark 1. +Relative volume. 𝑉 +𝑉0 +greater than unity. If zero, erosion in tension is inactive. +, for erosion in tension. Typically, use values +Relative volume, 𝑉 +𝑉0 +values less than unity. If zero, erosion in compression is inactive. +, for erosion in compression. Typically, use +YM +Young’s modulus (used for null beams and shells only) +*MAT_NULL +DESCRIPTION +PR +Poisson’s ratio (used for null beams and shells only) +Remarks: +These remarks apply to solids and thick shells only. +1. When used with solids or thick shells, this material must be used with an +equation-of-state. Pressure cutoff is negative in tension. A (deviatoric) viscous +stress of the form +𝜎′𝑖𝑗 = 2𝜇𝜀′̇ +𝑚2 𝑠] [ +𝑚2] ~ [ +is computed for nonzero 𝜇 where 𝜀′̇ +𝑖𝑗 is the deviatoric strain rate. 𝜇 is the dy- +namic viscosity. For example, in SI unit system, 𝜇 may have a unit of [Pa*s]. +𝑖𝑗 +] +[ +2. Null material has no shear stiffness (except from viscosity) and hourglass +control must be used with great care. In some applications, the default hour- +glass coefficient may lead to significant energy losses. In general for fluid, the +hourglass coefficient QM should be small (in the range 1.0E-6 to 1.0E-4) and the +hourglass type IHQ should be set to 1 (default). +3. The Null material has no yield strength and behaves in a fluid-like manner. +4. The cut-off pressure, PC, must be defined to allow for a material to “numerical- +ly” cavitate. In other words, when a material undergoes dilatation above cer- +tain magnitude, it should no longer be able to resist this dilatation. Since +dilatation stress or pressure is negative, setting PC limit to a very small negative +number would allow for the material to cavitate once the pressure in the mate- +rial goes below this negative value. +*MAT_ELASTIC_PLASTIC_HYDRO_{OPTION} +This is Material Type 10. This material allows the modeling of an elastic-plastic +hydrodynamic material and requires an equation-of-state (*EOS). +Available options include: + +SPALL +STOCHASTIC +The keyword card can appear in two ways: +*MAT_ELASTIC_PLASTIC_HYDRO or MAT_010 +*MAT_ELASTIC_PLASTIC_HYDRO_SPALL or MAT_010_SPALL + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +G +F +4 +SIG0 +F +5 +EH +F +Default +none +none +none +0.0 +0.0 +6 +PC +F +-∞ +7 +FS +F +8 +CHARL +F +0.0 +0.0 +Spall Card. Additional card for SPALL keyword option. + Optional +Variable +1 +A1 +Type +F + Card 2 +1 +2 +A2 +F +2 +3 +4 +5 +6 +7 +8 +SPALL +F +3 +4 +5 +6 +7 +8 +Variable +EPS1 +EPS2 +EPS3 +EPS4 +EPS5 +EPS6 +EPS7 +EPS8 +Type +F +F +F +F +F +F +F +Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EPS9 +EPS10 +EPS11 +EPS12 +EPS13 +EPS14 +EPS15 +EPS16 +Type +F + Card 4 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +ES1 +ES2 +ES3 +ES4 +ES5 +ES6 +ES7 +ES8 +Type +F + Card 5 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +ES9 +ES10 +ES11 +ES12 +ES13 +ES14 +ES15 +ES16 +Type +F +F +F +F +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +G +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Shear modulus. +SIG0 +Yield stress, see comment below. +EH +PC +FS +Plastic hardening modulus, see definition below. +Pressure cutoff (≤ 0.0). If zero, a cutoff of -∞ is assumed. +Effective plastic strain at which erosion occurs. +Piecewise linear curve defining +the yield stress versus effective +plastic strain. As illustrated, the +yield stress at zero plastic strain +should be nonzero. +ep +Figure M10-1. Effective stress versus effective plastic strain curve. See EPS +and ES input. + VARIABLE +CHARL +DESCRIPTION +Characteristic element thickness for deletion. This applies to 2D +solid elements that lie on a boundary of a part. If the boundary +element thins down due to stretching or compression, and if it +thins to a value less than CHARL, the element will be deleted. +The primary application of this option is to predict the break-up +of axisymmetric shaped charge jets. +A1 +A2 +Linear pressure hardening coefficient. +Quadratic pressure hardening coefficient. +SPALL +Spall type: +EQ.0.0: default set to “1.0”, +EQ.1.0: tensile pressure is limited by PC, i.e., p is always ≥ PC, +EQ.2.0: if 𝜎max ≥ −PC element spalls and tension, 𝑝 < 0, is +never allowed, +EQ.3.0: 𝑝 < PC element spalls and tension, 𝑝 < 0, is never +allowed. +EPS +Effective plastic strain (True). Define up to 16 values. Care must +be taken that the full range of strains expected in the analysis is +covered. Linear extrapolation is used if the strain values exceed +the maximum input value. +ES +Effective stress. Define up to 16 values. +*MAT_ELASTIC_PLASTIC_HYDRO +If ES and EPS are undefined, the yield stress and plastic hardening modulus are taken +from SIG0 and EH. In this case, the bilinear stress-strain curve shown in M10-1 is +obtained with hardening parameter, 𝛽 = 1. The yield strength is calculated as +𝜎𝑦 = 𝜎0 + 𝐸ℎ𝜀̅𝑝 + (𝑎1 + 𝑝𝑎2)max[𝑝, 0] +The quantity 𝐸ℎ is the plastic hardening modulus defined in terms of Young’s modulus, +𝐸, and the tangent modulus, 𝐸𝑡, as follows +and 𝑝 is the pressure taken as positive in compression. +𝐸ℎ = +𝐸𝑡𝐸 +𝐸 − 𝐸𝑡 +. +If ES and EPS are specified, a curve like that shown in M10-1 may be defined. Effective +stress is defined in terms of the deviatoric stress tensor, 𝑠𝑖𝑗, as: +𝜎̅̅̅̅̅ = ( +2⁄ +𝑠𝑖𝑗𝑠𝑖𝑗) +and effective plastic strain by: +𝜀̅𝑝 = ∫ ( +2⁄ +𝑝 ) +𝑝 𝐷𝑖𝑗 +𝐷𝑖𝑗 +𝑑𝑡, +𝑝 is the plastic component of the rate of deformation tensor. +where t denotes time and 𝐷𝑖𝑗 +In this case the plastic hardening modulus on Card 1 is ignored and the yield stress is +given as +where the value for 𝑓 (𝜀̅𝑝) is found by interpolation from the data curve. +𝜎𝑦 = 𝑓 (𝜀̅𝑝), +A choice of three spall models is offered to represent material splitting, cracking, and +failure under tensile loads. The pressure limit model, SPALL = 1, limits the hydrostatic +tension to the specified value, 𝑝cut. If pressures more tensile than this limit are +calculated, the pressure is reset to pcut. This option is not strictly a spall model, since +the deviatoric stresses are unaffected by the pressure reaching the tensile cutoff, and the +pressure cutoff value, pcut, remains unchanged throughout the analysis. +The maximum principal stress spall model, SPALL = 2, detects spall if the maximum +principal stress, 𝜎max, exceeds the limiting value -𝑝cut. Note that the negative sign is +required because 𝑝cut is measured positive in compression, while 𝜎max is positive in +tension. Once spall is detected with this model, the deviatoric stresses are reset to zero, +and no hydrostatic tension (𝑝 < 0) is permitted. If tensile pressures are calculated, they +are reset to 0 in the spalled material. Thus, the spalled material behaves as a rubble or +incohesive material. +The hydrostatic tension spall model, SPALL = 3, detects spall if the pressure becomes +more tensile than the specified limit, 𝑝cut. Once spall is detected the deviatoric stresses +are reset to zero, and nonzero values of pressure are required to be compressive +(positive). If hydrostatic tension (𝑝 < 0) is subsequently calculated, the pressure is reset +to 0 for that element. +This model is applicable to a wide range of materials, including those with pressure- +dependent yield behavior. The use of 16 points in the yield stress versus effective +plastic strain curve allows complex post-yield hardening behavior to be accurately +represented. In addition, the incorporation of an equation of state permits accurate +modeling of a variety of different materials. The spall model options permit +incorporation of material failure, fracture, and disintegration effects under tensile loads. +The STOCHASTIC option allows spatially varying yield and failure behavior. See *DE- +FINE_STOCHASTIC_VARIATION for additional information. +*MAT_STEINBERG +This is Material Type 11. This material is available for modeling materials deforming at +very high strain rates (> 105) and can be used with solid elements. The yield strength is +a function of temperature and pressure. An equation of state determines the pressure. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F + Card 2 +Variable +Type + Card 3 +Variable +1 +B +F +1 +PC +Type +F + Card 4 +1 +2 +BP +F +2 +SPALL +F +2 +3 +G0 +F +3 +H +F +3 +RP +F +3 +7 +8 +GAMA +SIGM +4 +5 +SIGO +BETA +F +4 +F +F +4 +F +5 +A +F +5 +6 +N +F +6 +F +7 +TMO +GAMO +F +6 +F +7 +F +8 +SA +F +8 +FLAG +MMN +MMX +ECO +EC1 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +EC2 +EC3 +EC4 +EC5 +EC6 +EC7 +EC8 +EC9 +Type +F +F +F +F +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +G0 +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Basic shear modulus. +VARIABLE +DESCRIPTION +SIGO +BETA +σo, see defining equations. +β, see defining equations. +N +n, see defining equations. +GAMA +SIGM +B +BP +H +F +A +γi, initial plastic strain, see defining equations. +σm, see defining equations. +b, see defining equations. +b′, see defining equations. +h, see defining equations. +f, see defining equations. +Atomic weight (if = 0.0, R′ must be defined). +TMO +Tmo, see defining equations. +GAMO +γo, see defining equations. +SA +PC +a, see defining equations. +Pressure cutoff (default = -1.e+30) +SPALL +Spall type: +EQ.0.0: default set to “2.0”, +EQ.1.0: p ≥ PC, +EQ.2.0: if σmax ≥ -PC element spalls and tension, p < 0, is +never allowed, +EQ.3.0: p < PC element spalls and tension, p < 0, is never +allowed. +R′. If R′≠0.0, A is not defined. +Set to 1.0 for μ coefficients for the cold compression energy fit. +Default is η. +RP +FLAG +MMN +μmin or ηmin. Optional μ or η minimum value. +*MAT_STEINBERG +DESCRIPTION +MMX +μmax or ηmax. Optional μ or η maximum value. +EC0, …, EC9 +Cold compression energy coefficients (optional). +Remarks: +Users who have an interest in this model are encouraged to study the paper by +Steinberg and Guinan which provides the theoretical basis. Another useful reference is +the KOVEC user’s manual. +In terms of the foregoing input parameters, we define the shear modulus, 𝐺, before the +material melts as: +𝐺 = 𝐺0 [1 + 𝑏𝑝𝑉 +3⁄ − ℎ ( +𝐸𝑖 − 𝐸𝑐 +3𝑅′ +− 300)] 𝑒 +−𝑓 𝐸𝑖 +𝐸𝑚−𝐸𝑖 +where 𝑝 is the pressure, 𝑉 is the relative volume, 𝐸𝑐 is the cold compression energy: +𝐸𝑐(𝑥) = ∫ 𝑝𝑑𝑥 +− +900𝑅′exp(𝑎𝑥) +(1 − 𝑥)2(𝛾0−𝑎−1 +2⁄ ) +, +𝑥 = 1 − 𝑉, +and 𝐸𝑚 is the melting energy: +which is in terms of the melting temperature 𝑇𝑚 (𝑥): +𝐸𝑚(𝑥) = 𝐸𝑐(𝑥) + 3𝑅′𝑇𝑚(𝑥) +𝑇𝑚(𝑥) = +𝑇𝑚𝑜exp(2𝑎𝑥) +𝑉2(𝛾𝑜−𝑎−1 +3⁄ ) +and the melting temperature at 𝜌 = 𝜌𝑜, 𝑇𝑚𝑜. +In the above equation 𝑅′ is defined by +𝑅′ = +𝑅𝜌 +where 𝑅 is the gas constant and A is the atomic weight. If 𝑅 is not defined, LS-DYNA +computes it with 𝑅 in the cm-gram-microsecond system of units. +The yield strength σy is given by: +𝜎𝑦 = 𝜎0 +′ [1 + 𝑏′𝑝𝑉 +3⁄ − ℎ ( +𝐸𝑖 − 𝐸𝑐 +3𝑅′ +− 300)] 𝑒 +−𝑓 𝐸𝑖 +𝐸𝑚−𝐸𝑖 +if 𝐸𝑚 exceeds 𝐸𝑖. Here, 𝜎0 +′ is given by: +𝜎0 +′ = 𝜎0[1 + 𝛽(𝛾𝑖 + 𝜀̅𝑝)]𝑛 +where 0 is the initial yield stress and 𝑖 is the initial plastic strain. If the work-hardened + is set equal to 𝑚. After the materials melt, 𝜎𝑦 and 𝐺 are +yield stress 𝜎0 +set to one half their initial value. +′ exceeds 𝑚, 𝜎0 +′ +If the coefficients EC0, …, EC9 are not defined above, LS-DYNA will fit the cold +compression energy to a ten term polynomial expansion either as a function of μ or η +depending on the input variable, FLAG, as: +𝐸𝑐(𝜂𝑖) = ∑ 𝐸𝐶𝑖𝜂𝑖 +𝑖=0 +𝐸𝑐(𝜇𝑖) = ∑ 𝐸𝐶𝑖𝜇𝑖 +𝑖=0 +where ECi is the ith coefficient and: +𝜂 = +𝜌𝑜 +𝜇 = +𝜌𝑜 +− 1 +A linear least squares method is used to perform the fit. +A choice of three spall models is offered to represent material splitting, cracking, and +failure under tensile loads. The pressure limit model, SPALL = 1, limits the hydrostatic +tension to the specified value, pcut. If pressures more tensile than this limit are +calculated, the pressure is reset to pcut. This option is not strictly a spall model, since +the deviatoric stresses are unaffected by the pressure reaching the tensile cutoff, and the +pressure cutoff value, pcut, remains unchanged throughout the analysis. The maximum +principal stress spall model, SPALL = 2, detects spall if the maximum principal stress, +σmax, exceeds the limiting value -pcut. Note that the negative sign is required because +pcut is measured positive in compression, while σmax is positive in tension. Once spall +is detected with this model, the deviatoric stresses are reset to zero, and no hydrostatic +tension (p < 0) is permitted. If tensile pressures are calculated, they are reset to 0 in the +spalled material. Thus, the spalled material behaves as a rubble or incohesive material. +The hydrostatic tension spall model, SPALL = 3, detects spall if the pressure becomes +more tensile than the specified limit, pcut. Once spall is detected the deviatoric stresses +are reset to zero, and nonzero values of pressure are required to be compressive +(positive). If hydrostatic tension (p < 0) is subsequently calculated, the pressure is reset +to 0 for that element. +This model is applicable to a wide range of materials, including those with pressure- +dependent yield behavior. In addition, the incorporation of an equation of state permits +accurate modeling of a variety of different materials. The spall model options permit +incorporation of material failure, fracture, and disintegration effects under tensile loads. +*MAT_STEINBERG_LUND +This is Material Type 11. This material is a modification of the Steinberg model above +to include the rate model of Steinberg and Lund [1989]. An equation of state +determines the pressure. +The keyword cards can appear in two ways: +*MAT_STEINBERG_LUND or MAT_011_LUND + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F + Card 2 +Variable +Type + Card 3 +Variable +1 +B +F +1 +PC +Type +F + Card 4 +1 +2 +BP +F +2 +SPALL +F +2 +3 +G0 +F +3 +H +F +3 +RP +F +3 +7 +8 +GAMA +SIGM +4 +5 +SIGO +BETA +F +4 +F +F +4 +F +5 +A +F +5 +6 +N +F +6 +F +7 +TMO +GAMO +F +6 +F +7 +F +8 +SA +F +8 +FLAG +MMN +MMX +ECO +EC1 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +EC2 +EC3 +EC4 +EC5 +EC6 +EC7 +EC8 +EC9 +Type +F +F +F +F +F +F +F +Card 5 +Variable +1 +UK +Type +F +2 +C1 +F +3 +C2 +F +4 +YP +F +5 +YA +F +6 +YM +F +7 +8 + VARIABLE +DESCRIPTION +MID +RO +G0 +SIGO +BETA +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Basic shear modulus. +σo, see defining equations. +β, see defining equations. +N +n, see defining equations. +GAMA +SIGM +B +BP +H +F +A +γi, initial plastic strain, see defining equations. +σm, see defining equations. +b, see defining equations. +b′, see defining equations. +h, see defining equations. +f, see defining equations. +Atomic weight (if = 0.0, R′ must be defined). +TMO +Tmo, see defining equations. +GAMO +γo, see defining equations. +SA +PC +a, see defining equations. +pcut or -σf (default = -1.e+30) +VARIABLE +DESCRIPTION +SPALL +Spall type: +EQ.0.0: default set to “2.0”, +EQ.1.0: p ≥ pmin, +EQ.2.0: if 𝜎max ≥ −pmin element spalls and tension, p < 0, is +never allowed, +EQ.3.0: p < −pmin element spalls and tension, p < 0, is never +allowed. +R′. If R′≠0.0, A is not defined. +Set to 1.0 for μ coefficients for the cold compression energy fit. +Default is η. +μmin or ηmin. Optional μ or η minimum value. +μmax or ηmax. Optional μ or η maximum value. +RP +FLAG +MMN +MMX +EC0, …, EC9 +Cold compression energy coefficients (optional). +UK +C1 +C2 +YP +YA +Activation energy for rate dependent model. +Exponent prefactor in rate dependent model. +Coefficient of drag term in rate dependent model. +Peierls stress for rate dependent model. +A thermal yield stress for rate dependent model. +YMAX +Work hardening maximum for rate model. +Remarks: +This model is similar in theory to the *MAT_STEINBERG above but with the addition +of rate effects. When rate effects are included, the yield stress is given by: +𝜎𝑦 = {𝑌𝑇(𝜀̇𝑝, 𝑇) + 𝑌𝐴𝑓 (𝜀𝑝)} +𝐺(𝑝, 𝑇) +𝐺0 +There are two imposed limits on the yield stress. The first is on the thermal yield stress: +𝑌𝐴𝑓 (𝜀𝑝) = 𝑌𝐴[1 + 𝛽(𝛾𝑖 + 𝜀𝑝)]𝑛 ≤ 𝑌max +and the second is on the thermal part: +𝑌𝑇 ≤ 𝑌𝑃 +R' is the heat capacity per unit volume. Most handbooks give the heat capacity per unit +mass or per mole. To obtain R', multiply the heat capacity per unit mass by the initial +density, and to obtain R' from the heat capacity per mole, divide it by the mass per mole +and then multiply the result by the initial density. The mass per mole in grams equals +the atomic weight. +For example, the heat capacity per mole for aluminum is 24.2 J/mole/K, the density is +2.70 g/cc, and the atomic weight is 13. The heat capacity per cubic centimeter is +therefore (24.2 J/mole/K) / (13g/mole) × (2.70g/cc)= 5.026 J/cc/K. To convert it to +J/m3/K, multiply the result by 106 cc/m3 to obtain a final heat capacity of 5.026e6 +J/m3/K. +*MAT_ISOTROPIC_ELASTIC_PLASTIC +This is Material Type 12. This is a very low cost isotropic plasticity model for three- +dimensional solids. In the plane stress implementation for shell elements, a one-step +radial return approach is used to scale the Cauchy stress tensor to if the state of stress +exceeds the yield surface. This approach to plasticity leads to inaccurate shell thickness +updates and stresses after yielding. This is the only model in LS-DYNA for plane stress +that does not default to an iterative approach. +Card +1 +Variable +MID +2 +RO +Type +A8 +F +3 +G +F +4 +5 +6 +7 +8 +SIGY +ETAN +BULK +F +F +F + VARIABLE +DESCRIPTION +MID +RO +G +SIGY +ETAN +BULK +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Shear modulus. +Yield stress. +Plastic hardening modulus. +Bulk modulus, K. +Remarks: +Here the pressure is integrated in time +where 𝜀̇𝑖𝑖 is the volumetric strain rate. +𝑝̇ = −𝐾𝜀̇𝑖𝑖 +*MAT_ISOTROPIC_ELASTIC_FAILURE +This is Material Type 13. This is a non-iterative plasticity with simple plastic strain +failure model. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +G +F +4 +5 +6 +7 +8 +SIGY +ETAN +BULK +F +F +F +Default +none +none +none +none +0.0 +none + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EPF +PRF +REM +TREM +Type +F +F +F +F +Default +none +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +MID +RO +G +SIGY +ETAN +BULK +EPF +PRF +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Shear modulus. +Yield stress. +Plastic hardening modulus. +Bulk modulus. +Plastic failure strain. +Failure pressure (≤ 0.0). +*MAT_ISOTROPIC_ELASTIC_FAILURE +DESCRIPTION +REM +Element erosion option: +EQ.0.0: failed element eroded after failure, +NE.0.0: element is kept, no removal except by Δt below. +TREM +Δt for element removal: +EQ.0.0: Δt is not considered (default), +GT.0.0: element eroded if element time step size falls below Δt. +Remarks: +When the effective plastic strain reaches the failure strain or when the pressure reaches +the failure pressure, the element loses its ability to carry tension and the deviatoric +stresses are set to zero, i.e., the material behaves like a fluid. If Δt for element removal is +defined the element removal option is ignored. +The element erosion option based on Δt must be used cautiously with the contact +options. Nodes to surface contact is recommended with all nodes of the eroded brick +elements included in the node list. As the elements are eroded the mass remains and +continues to interact with the master surface. +*MAT_SOIL_AND_FOAM_FAILURE +This is Material Type 14. The input for this model is the same as for *MATERIAL_- +SOIL_AND_FOAM (Type 5); however, when the pressure reaches the tensile failure +pressure, the element loses its ability to carry tension. It should be used only in +situations when soils and foams are confined within a structure or are otherwise +confined by nodal boundary conditions. +*MAT_JOHNSON_COOK_{OPTION} +Available options include: + +STOCHASTIC +This is Material Type 15. The Johnson/Cook strain and temperature sensitive plasticity +is sometimes used for problems where the strain rates vary over a large range and +adiabatic temperature increases due to plastic heating cause material softening. When +used with solid elements this model requires an equation-of-state. If thermal effects +and damage are unimportant, the much less expensive *MAT_SIMPLIFIED_JOHN- +SON_COOK model is recommended. The simplified model can be used with beam +elements. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +G +F +4 +E +F +5 +PR +F +6 +DTF +F +7 +VP +F +8 +RATEOP +F +Default +none +none +none +none +none +0.0 +0.0 +0.0 + Card 2 +Variable +Type +1 +A +F +2 +B +F +3 +N +F +4 +C +F +5 +M +F +6 +TM +F +7 +TR +F +8 +EPS0 +F +Default +none +0.0 +0.0 +0.0 +none +none +none +none +Card 3 +Variable +1 +CP +Type +F +2 +PC +F +3 +SPALL +F +4 +IT +F +5 +D1 +F +6 +D2 +F +7 +D3 +F +8 +D4 +F +Default +none +0.0 +2.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +D5 +C2/P/XNP +EROD +EFMIN +NUMINT +Type +F +F +F +F +Default +0.0 +0.0 +0.0 +10-6 +F +0. + VARIABLE +DESCRIPTION +MID +RO +G +E +PR +DTF +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Shear modulus. G and an equation-of-state are required for +element types that use a 3D stress update, e.g., solids, 2D shell +forms 13-15, tshell forms 3 and 5. For other element types, G is +ignored, and E and PR must be provided. +Young’s Modulus . +Poisson’s ratio . +Minimum time step size for automatic element deletion (shell +elements). The element will be deleted when the solution time +step size drops below DTF × TSSFAC where TSSFAC is the time +step scale factor defined by *CONTROL_TIMESTEP. +VP +Formulation for rate effects: +EQ.0.0: Scale yield stress (default), +EQ.1.0: Viscoplastic formulation. +*MAT_JOHNSON_COOK +DESCRIPTION +RATEOP +Form of strain-rate term. RATEOP is ignored if VP = 0. +EQ.0.0: Log-Linear Johnson-Cook (default), +EQ.1.0: Log-Quadratic Huh-Kang (2 parameters), +EQ.2.0: Exponential Allen-Rule-Jones, +EQ.3.0: Exponential Cowper-Symonds (2 parameters). +EQ.4.0: Nonlinear rate coefficient (2 parameters). +A +B +N +C +M +TM +TR +EPS0 +CP +PC +See equations below +See equations below +See equations below +See equations below +See equations below +Melt temperature +Room temperature +Quasi-static threshold strain rate. Ideally, this value represents +the highest strain rate for which no rate adjustment to the flow +stress is needed, and is input in units of [time]−1. For example, if +strain rate effects on the flow stress first become apparent at +strain rates greater than 10−2s−1 and the system of units for the +model input is kg, mm, ms, then EPSO should be set to 10−5, +which is 10−2s−1 in units of ms. +Specific heat (superseded by heat capacity in *MAT_THER- +MAL_OPTION if a coupled thermal/structural analysis) +Tensile failure stress or tensile pressure cutoff (PC < 0.0) +VARIABLE +DESCRIPTION +SPALL +Spall type: +EQ.0.0: default set to “2.0”. +EQ.1.0: Tensile pressure is limited by PC, i.e., 𝑝 is always ≥ PC. +Shell Element Specific Behavior: +EQ.2.0: Shell elements are deleted when 𝜎max ≥ −PC. +EQ.3.0: Shell elements are deleted when 𝑝 < 𝑃𝐶. +Solid Element Specific Behavior +EQ.2.0: For solid elements 𝜎max ≥ −PC resets tensile stresses to +zero. Compressive stress are still allowed. +EQ.3.0: For solid elements 𝑝 < PC resets the pressure to zero +thereby disallowing tensile pressure. +IT +Plastic strain iteration option. This input applies to solid +elements only since it is always necessary to iterate for the shell +element plane stress condition. +EQ.0.0: no iterations (default), +EQ.1.0: accurate iterative solution for plastic strain. Much +more expensive than default. +D1 - D5 +Failure parameters, see equations below. A negative input of D3 +will be converted to its absolute value. +C2/P/XNP +Optional strain-rate parameter. +Field Var Model +C2 +P +XNP +𝐶2 Huh-Kang +𝑃 Cowper-Symonds +𝑛′ Nonlinear Rate Coefficient +These models are documented in the remarks. +EROD +Erosion Flag: +EQ.0.0: default, element erosion allowed. +NE.0.0: element does not erode; deviatoric stresses set to zero +when element fails. +EFMIN +The lower bound for calculated strain at fracture . +NUMINT +*MAT_JOHNSON_COOK +DESCRIPTION +Number of through thickness integration points which must fail +before the shell element is deleted. (If zero, all points must fail.) +Since nodal fiber rotations limit strains at active integration +points, the default, which is to require that all integration points +fail, is not recommended, because elements undergoing large +strain are often not deleted using this criterion. Better results may +be obtained when NUMINT is set to 1 or a number less than one +half of the number of through thickness points. +For example, if four through thickness points are used, NUMINT +should not exceed 2, even for fully integrated shells which have +16 integration points. +Remarks: +Johnson and Cook express the flow stress as +𝜎𝑦 = (𝐴 + 𝐵𝜀̅𝑝𝑛 +)(1 + 𝑐 ln 𝜀̇∗)(1 − 𝑇∗𝑚) +Where, +𝐴, 𝐵, 𝑐, 𝑛, and 𝑚 = input constants +𝜀̅𝑝 = effective plastic strain +𝜀̇∗ = +⎧ ε̅ +{{ +⎨ +{{ +⎩ +EPS0 +̇𝑝 +ε̅ +EPS0 +for VP.EQ.0 +(normalized effective total strain-rate) +for VP.EQ. 1 +(normalized effective plastic strain rate) +𝑇∗ = homologous temperature = +𝑇 − 𝑇room +𝑇melt − 𝑇room +The quantity 𝑇 − 𝑇room is stored as extra history variable 5. +Constants for a variety of materials are provided in Johnson and Cook [1983]. A fully +viscoplastic formulation is optional (VP) which incorporates the rate equations within +the yield surface. An additional cost is incurred but the improvement is that results can +be dramatic. +Due to nonlinearity in the dependence of flow stress on plastic strain, an accurate value +of the flow stress requires iteration for the increment in plastic strain. However, by +using a Taylor series expansion with linearization about the current time, we can solve +for σy with sufficient accuracy to avoid iteration. +2-136 (EOS) +*MAT_015 +𝜀𝑓 = max([𝐷1 + 𝐷2exp𝐷3𝜎 ∗][1 + 𝐷4ln𝜀̇∗][1 + 𝐷5𝑇∗], EFMIN) +where σ* is the ratio of pressure divided by effective stress +Fracture occurs when the damage parameter +𝜎 ∗ = +𝜎eff +𝐷 = ∑ +Δ𝜀𝑝 +𝜀𝑓 +reaches the value of 1. 𝐷 is stored as extra history variable 4 in shell elements and extra +history variable 6 in solid elements. +A choice of three spall models is offered to represent material splitting, cracking, and +failure under tensile loads. The pressure limit model limits the minimum hydrostatic +pressure to the specified value, 𝑝 ≥ 𝑝min. If pressures more tensile than this limit are +calculated, the pressure is reset to 𝑝min. This option is not strictly a spall model since the +deviatoric stresses are unaffected by the pressure reaching the tensile cutoff and the +pressure cutoff value 𝑝min remains unchanged throughout the analysis. The maximum +principal stress spall model detects spall if the maximum principal stress, 𝜎max, exceeds +the limiting value 𝜎𝑝. Once spall in solids is detected with this model, the deviatoric +stresses are reset to zero and no hydrostatic tension is permitted. If tensile pressures are +calculated, they are reset to 0 in the spalled material. Thus, the spalled material behaves +as rubble. The hydrostatic tension spall model detects spall if the pressure becomes +more tensile than the specified limit, 𝑝min. Once spall in solids is detected with this +model, the deviatoric stresses are set to zero and the pressure is required to be +compressive. If hydrostatic tension is calculated then the pressure is reset to 0 for that +element. +In addition to the above failure criterion, this material model also supports a shell +element deletion criterion based on the maximum stable time step size for the element, +Δ𝑡max. Generally, Δ𝑡max goes down as the element becomes more distorted. To assure +stability of time integration, the global LS-DYNA time step is the minimum of the Δ𝑡max +values calculated for all elements in the model. Using this option allows the selective +deletion of elements whose time step Δ𝑡max has fallen below the specified minimum +time step, Δ𝑡crit. Elements which are severely distorted often indicate that material has +failed and supports little load, but these same elements may have very small time steps +and therefore control the cost of the analysis. This option allows these highly distorted +elements to be deleted from the calculation, and, therefore, the analysis can proceed at a +larger time step, and, thus, at a reduced cost. Deleted elements do not carry any load, +and are deleted from all applicable slide surface definitions. Clearly, this option must +be judiciously used to obtain accurate results at a minimum cost. +Material type 15 is applicable to the high rate deformation of many materials including +most metals. Unlike the Steinberg-Guinan model, the Johnson-Cook model remains +valid down to lower strain rates and even into the quasistatic regime. Typical +applications include explosive metal forming, ballistic penetration, and impact. +Optional Strain Rate Forms: +The standard Johnson-Cook strain rate term is linear in the logarithm of the strain rate: +1 + 𝐶 ln 𝜀̇∗ +Some additional data fitting capability can be obtained by using the quadratic form +proposed by Huh & Kang [2002]: +1 + 𝐶 ln 𝜀̇∗ + 𝐶2(ln 𝜀̇∗)2 +Three additional exponential forms are available, one due to Allen, Rule & Jones [1997], +(𝜀̇∗)𝑐 +the Cowper-Symonds-like [1958] form +and the nonlinear rate coefficient, +𝜀̇eff +⎟⎞ +𝐶 ⎠ +⎜⎛ +⎝ +1 + +𝑛′ +𝑝 ) +1 + 𝐶(𝜀eff +ln 𝜀̇∗. +The four additional rate forms (RATEOP = 1, 2, 3 or 4) are currently available for solid +& shell elements but only when the viscoplastic rate option is active (VP = 1). If VP is +set to zero, RATEOP is ignored. See Huh and Kang [2002], Allen, Rule, and Jones +[1997], and Cowper and Symonds [1958]. +The STOCHASTIC option allows spatially varying yield and failure behavior. See *DE- +FINE_STOCHASTIC_VARIATION for additional information. +*MAT_016 +This is Material Type 16. This model has been used to analyze buried steel reinforced +concrete structures subjected to impulsive loadings. +5 +6 +7 +8 + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +G +F +4 +PR +F +Default +none +none +none +none + Card 2 +1 +Variable +SIGF +Type +F +2 +A0 +F +3 +A1 +F +4 +A2 +F +5 +6 +A0F +A1F +F +F +7 +B1 +F +8 +PER +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 3 +Variable +1 +ER +2 +3 +4 +5 +6 +7 +8 +PRR +SIGY +ETAN +LCP +LCR +Type +F +F +F +F +F +F +Default +0.0 +0.0 +none +0.0 +none +none +Variable +1 +X1 +Type +F +*MAT_PSEUDO_TENSOR +2 +X2 +F +3 +X3 +F +4 +X4 +F +5 +X5 +F +6 +X6 +F +7 +X7 +F +8 +X8 +F +Default +none +none +none +none +none +none +none +none + Card 5 +Variable +1 +X9 +2 +3 +4 +5 +6 +7 +8 +X10 +X11 +X12 +X13 +X14 +X15 +X16 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +YS1 +YS2 +YS3 +YS4 +YS5 +YS6 +YS7 +YS8 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none + Card 7 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +YS9 +YS10 +YS11 +YS12 +YS13 +YS14 +YS15 +YS16 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +VARIABLE +DESCRIPTION +MID +RO +G +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Shear modulus. +Poisson’s ratio. +SIGF +Tensile cutoff (maximum principal stress for failure). +A0 +A1 +A2 +A0F +A1F +B1 +PER +ER +PRR +SIGY +ETAN +LCP +LCR +Xn +Cohesion. +Pressure hardening coefficient. +Pressure hardening coefficient. +Cohesion for failed material. +Pressure hardening coefficient for failed material. +Damage scaling factor (or exponent in Mode II.C). +Percent reinforcement. +Elastic modulus for reinforcement. +Poisson’s ratio for reinforcement. +Initial yield stress. +Tangent modulus/plastic hardening modulus. +Load curve ID giving rate sensitivity for principal material, see +*DEFINE_CURVE. +Load curve ID giving rate sensitivity for reinforcement, see *DE- +FINE_CURVE. +Effective plastic strain, damage, or pressure. See discussion +below. +YSn +Yield stress (Mode I) or scale factor (Mode II.B or II.C). +Mohr-Coulomb +Tresca +Friction Angle +Cohesion +Figure M16-1. Mohr-Coulomb surface with a Tresca Limit. +Pressure +Remarks: +This model can be used in two major modes - a simple tabular pressure-dependent +yield surface, and a potentially complex model featuring two yield versus pressure +functions with the means of migrating from one curve to the other. For both modes, +load curve LCP is taken to be a strain rate multiplier for the yield strength. Note that +this model must be used with equation-of-state type 8, 9 or 11. +Response Mode I. Tabulated Yield Stress Versus Pressure +This model is well suited for implementing standard geologic models like the Mohr- +Coulomb yield surface with a Tresca limit, as shown in Figure M16-1. Examples of +converting conventional triaxial compression data to this type of model are found in +(Desai and Siriwardane, 1984). Note that under conventional triaxial compression +conditions, the LS-DYNA input corresponds to an ordinate of 𝜎1 − 𝜎3 rather than the +more widely used +, where 𝜎1 is the maximum principal stress and 𝜎3is the +minimum principal stress. +𝜎1−𝜎3 +This material combined with equation-of-state type 9 (saturated) has been used very +successfully to model ground shocks and soil-structure interactions at pressures up to +100kbars (approximately 1.5 x 106 psi). +Figure M16-2. Two-curve concrete model with damage and failure +Pressure +To invoke Mode I of this model, set a0, a1, a2, b1, a0f, and a1f to zero. The tabulated +values of pressure should then be specified on cards 4 and 5, and the corresponding +values of yield stress should be specified on cards 6 and 7. The parameters relating to +reinforcement properties, initial yield stress, and tangent modulus are not used in this +response mode, and should be set to zero. +Simple tensile failure +Note that a1f is reset internally to 1/3 even though it is input as zero; this defines a +failed material curve of slope 3p, where p denotes pressure (positive in compression). In +this case the yield strength is taken from the tabulated yield vs. pressure curve until the +maximum principal stress (𝜎1) in the element exceeds the tensile cutoff 𝜎cut (input as +variable SIGF). When 𝜎1 > 𝜎cut is detected, the yield strength is scaled back by a +fraction of the distance between the two curves in each of the next 20 time steps so that +after those 20 time steps, the yield strength is defined by the failure curve. The only +way to inhibit this feature is to set 𝜎𝑐𝑢𝑡 (SIGF) arbitrarily large. +Response Mode II. Two Curve Model with Damage and Failure +This approach uses two yield versus pressure curves of the form +𝜎𝑦 = 𝑎0 + +𝑎1 + 𝑎2𝑝 +The upper curve is best described as the maximum yield strength curve and the lower +curve is the failed material curve. There are a variety of ways of moving between the +two curves and each is discussed below. +MODE II. A: Simple tensile failure +Define a0, a1, a2, a0f and a1f, set b1 to zero, and leave cards 4 through 7 blank. In this case +the yield strength is taken from the maximum yield curve until the maximum principal +stress (𝜎1) in the element exceeds the tensile cutoff (𝜎cut). When 𝜎1 > 𝜎cut is detected, +the yield strength is scaled back by a fraction of the distance between the two curves in +each of the next 20 time steps so that after those 20 time steps, the yield strength is +defined by the failure curve. +Mode II.B: Tensile failure plus plastic strain scaling +Define a0, a1, a2, a0f and a1f, set b1 to zero, and user cards 4 through 7 to define a scale +factor, η, versus effective plastic strain. LS-DYNA evaluates η at the current effective +plastic strain and then calculated the yield stress as +𝜎yield = 𝜎failed + 𝜂(𝜎max − 𝜎failed) +where 𝜎max and 𝜎failed are found as shown in Figure M16-2. This yield strength is then +subject to scaling for tensile failure as described above. This type of model allows the +description of a strain hardening or softening material such as concrete. +Mode II.C: Tensile failure plus damage scaling +The change in yield stress as a function of plastic strain arises from the physical +mechanisms such as internal cracking, and the extent of this cracking is affected by the +hydrostatic pressure when the cracking occurs. This mechanism gives rise to the +"confinement" effect on concrete behavior. To account for this phenomenon, a +"damage" function was defined and incorporated. This damage function is given the +form: +𝜀𝑝 +𝜆 = ∫ (1 + +𝜎cut +) +−𝑏1 +𝑑𝜀𝑝 +Define a0, a1, a2, a0f and a1f, and b1. Cards 4 though 7 now give η as a function of λ and +scale the yield stress as +and then apply any tensile failure criteria. +𝜎yield = 𝜎failed + 𝜂(𝜎max − 𝜎failed) +Mode II Concrete Model Options +Material Type 16 Mode II provides for the automatic internal generation of a simple +"generic" model from concrete if A0 is negative then SIGF is assumed to be the +′ and –A0 is assumed to be a conversion +unconfined concrete compressive strength, 𝑓𝑐 +factor from LS-DYNA pressure units to psi. (For example, if the model stress units are +MPa, A0 should be set to –145.) In this case the parameter values generated internally +are +′ = SIGF +𝑓𝑐 +𝜎𝑐𝑢𝑡 = 1.7 +′2 +⎜⎛ 𝑓𝑐 +⎟⎞ +−𝐴0⎠ +⎝ +𝑎0 = +′ +𝑓𝑐 +𝑎1 = +𝑎2 = +′ +3𝑓𝑐 +𝑎0𝑓 = 0 +𝑎1𝑓 = 0.385 +Note that these a0f and a1f defaults will be overridden by non zero entries on Card 3. If +plastic strain or damage scaling is desired, Cards 5 through 8 and b1 should be specified +in the input. When a0 is input as a negative quantity, the equation-of-state can be given +as 0 and a trilinear EOS Type 8 model will be automatically generated from the +unconfined compressive strength and Poisson's ratio. The EOS 8 model is a simple +pressure versus volumetric strain model with no internal energy terms, and should give +reasonable results for pressures up to 5kbar (approximately 75,000 psi). +Mixture model +A reinforcement fraction, 𝑓𝑟, can be defined (indirectly as PER/100) along with +properties of the reinforcement material. The bulk modulus, shear modulus, and yield +strength are then calculated from a simple mixture rule, i.e., for the bulk modulus the +rule gives: +𝐾 = (1 − 𝑓𝑟)𝐾𝑚 + 𝑓𝑟𝐾𝑟 +where 𝐾𝑚 and 𝐾𝑟 are the bulk moduli for the geologic material and the reinforcement +material, respectively. This feature should be used with caution. It gives an isotropic +effect in the material instead of the true anisotropic material behavior. A reasonable +approach would be to use the mixture elements only where the reinforcing exists and +plain elements elsewhere. When the mixture model is being used, the strain rate +multiplier for the principal material is taken from load curve N1 and the multiplier for +the reinforcement is taken from load curve N2. +A Suggestion +The LLNL DYNA3D manual from 1991 [Whirley and Hallquist] suggests using the +damage function (Mode II.C.) in Material Type 16 with the following set of parameters: +𝑎0 = +𝑎1 = +′ +𝑓𝑐 +𝑎2 = +𝑎0𝑓 = +′ +3𝑓𝑐 +′ +𝑓𝑐 +10 +𝑎1𝑓 = 1.5 +𝑏1 = 1.25 +*MAT_PSEUDO_TENSOR +Card 4: +Card 5: +Card 6: +Card 7: +0.0 +5.17E-04 +8.62E-06 +6.38E-04 +2.15E-05 +7.98E-04 +3.14E-05 +3.95E-04 +9.67E-04 +4.00E-03 +1.41E-03 +4.79E-03 +1.97E-03 +0.909 +2.59E-03 +3.27E-03 +0.309 +0.790 +0.383 +0.086 +0.543 +0.630 +0.247 +0.056 +0.840 +0.469 +0.173 +0.0 +0.975 +1.000 +0.136 +0.114 +This set of parameters should give results consistent with Dilger, Koch, and Kowalczyk, +[1984] for plane concrete. It has been successfully used for reinforced structures where +the reinforcing bars were modeled explicitly with embedded beam and shell elements. +The model does not incorporate the major failure mechanism - separation of the +concrete and reinforcement leading to catastrophic loss of confinement pressure. +However, experience indicates that this physical behavior will occur when this model +shows about 4% strain. +*MAT_017 +This is Material Type 17. This material may be used to model brittle materials which +fail due to large tensile stresses. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +6 +SIGY +ETAN +F +F +7 +FS +F +8 +PRF +F +Default +none +none +none +none +none +0.0 +none +0.0 +Optional card for crack propagation to adjacent elements : + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SOFT +CVELO +Type +F +F +Default +1.0 +0.0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +SIGY +ETAN +FS +PRF +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +Yield stress. +Plastic hardening modulus. +Fracture stress. +Failure or cutoff pressure (≤ 0.0). +SOFT +*MAT_ORIENTED_CRACK +DESCRIPTION +Factor by which the fracture stress is reduced when a crack is +coming from failed neighboring element. See remarks. +CVELO +Crack propagation velocity. See remarks. +Remarks: +This is an isotropic elastic-plastic material which includes a failure model with an +oriented crack. The von Mises yield condition is given by: +𝜙 = 𝐽2 − +𝜎𝑦 +where the second stress invariant, 𝐽2, is defined in terms of the deviatoric stress +components as +𝐽2 = +𝑠𝑖𝑗𝑠𝑖𝑗 +and the yield stress,𝜎𝑦, is a function of the effective plastic strain, 𝜀eff +hardening modulus, 𝐸𝑝: +𝑝 , and the plastic +The effective plastic strain is defined as: +𝑝 +𝜎𝑦 = 𝜎0 + 𝐸𝑝𝜀eff +𝑝 = ∫ 𝑑𝜀eff +𝜀eff +where +𝑝 = √ +𝑑𝜀eff +𝑝 +𝑝 𝑑𝜀𝑖𝑗 +𝑑𝜀𝑖𝑗 +and the plastic tangent modulus is defined in terms of the input tangent modulus, 𝐸𝑡, as +𝐸𝑝 = +𝐸𝐸𝑡 +𝐸 − 𝐸𝑡 +Pressure in this model is found from evaluating an equation of state. A pressure cutoff +can be defined such that the pressure is not allowed to fall below the cutoff value. +The oriented crack fracture model is based on a maximum principal stress criterion. +When the maximum principal stress exceeds the fracture stress, 𝜎𝑓 , the element fails on +a plane perpendicular to the direction of the maximum principal stress. The normal +stress and the two shear stresses on that plane are then reduced to zero. This stress +reduction is done according to a delay function that reduces the stresses gradually to +zero over a small number of time steps. This delay function procedure is used to reduce +Figure M17-1. Thin structure (2 elements over thickness) with cracks and +necessary element numbering. +the ringing that may otherwise be introduced into the system by the sudden fracture. +The number of steps for stress reduction is 20 by default (CVELO = 0.0) or it is +internally computed if CVELO > 0.0 is given: +where Le is characteristic element length and Δt is time step size. +𝑛steps = int [ +𝐿𝑒 +CVELO × 𝛥𝑡 +] +After a tensile fracture, the element will not support tensile stress on the fracture plane, +but in compression will support both normal and shear stresses. The orientation of this +fracture surface is tracked throughout the deformation, and is updated to properly +model finite deformation effects. If the maximum principal stress subsequently exceeds +the fracture stress in another direction, the element fails isotropically. In this case the +element completely loses its ability to support any shear stress or hydrostatic tension, +and only compressive hydrostatic stress states are possible. Thus, once isotropic failure +has occurred, the material behaves like a fluid. +This model is applicable to elastic or elastoplastic materials under significant tensile or +shear loading when fracture is expected. Potential applications include brittle materials +such as ceramics as well as porous materials such as concrete in cases where pressure +hardening effects are not significant. +Crack propagation behavior to adjacent elements can be controlled via parameter SOFT +for thin, shell-like structures (e.g. only 2 or 3 solids over thickness). Additionally, LS- +DYNA has to know where the plane or solid element midplane is at each integration +point for projection of crack plane on this element midplane. Therefore, element +numbering has to be as shown in Figure M17-1. Only solid element type 1 is supported +with that option at the moment. +*MAT_POWER_LAW_PLASTICITY +This is Material Type 18. This is an isotropic plasticity model with rate effects which +uses a power law hardening rule. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +K +F +6 +N +F +7 +8 +SRC +SRP +F +F +Default +none +none +none +none +none +none +0.0 +0.0 + Card 2 +1 +Variable +SIGY +Type +F +2 +VP +F +3 +4 +5 +6 +7 +8 +EPSF +F +Default +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +K +N +SRC +SRP +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +Strength coefficient. +Hardening exponent. +Strain rate parameter, 𝐶, if zero, rate effects are ignored. +Strain rate parameter, 𝑃, if zero, rate effects are ignored. +VARIABLE +SIGY +DESCRIPTION +Optional input parameter for defining the initial yield stress, 𝜎𝑦. +Generally, this parameter is not necessary and the strain to yield +is calculated as described below. +LT.0.02: 𝜀𝑦𝑝 = SIGY +GT.0.02: See below. +Plastic failure strain for element deletion. +Formulation for rate effects: +EQ.0.0: Scale yield stress (default), +EQ.1.0: Viscoplastic formulation. +EPSF +VP +Remarks: +Elastoplastic behavior with isotropic hardening is provided by this model. The yield +stress, 𝜎𝑦, is a function of plastic strain and obeys the equation: +𝜎𝑦 = 𝑘𝜀𝑛 = 𝑘(𝜀𝑦𝑝 + 𝜀̅𝑝) +where 𝜀𝑦𝑝 is the elastic strain to yield and 𝜀̅𝑝is the effective plastic strain (logarithmic). +If SIGY is set to zero, the strain to yield if found by solving for the intersection of the +linearly elastic loading equation with the strain hardening equation: +𝜎 = 𝐸𝜀 +𝜎 = 𝑘 𝜀𝑛 +which gives the elastic strain at yield as: +If SIGY is nonzero and greater than 0.02 then: +𝜀𝑦𝑝 = ( +[ 1 +] +𝑛−1 +) +𝜀𝑦𝑝 = ( +[1 +𝑛] +) +𝜎𝑦 +Strain rate is accounted for using the Cowper and Symonds model which scales the +yield stress with the factor +1 + ( +𝑝⁄ +) +𝜀̇ +where 𝜀̇ is the strain rate. A fully viscoplastic formulation is optional which +incorporates the Cowper and Symonds formulation within the yield surface. An +additional cost is incurred but the improvement is results can be dramatic. +*MAT_STRAIN_RATE_DEPENDENT_PLASTICITY +This is Material Type 19. A strain rate dependent material can be defined. For an +alternative, see Material Type 24. Required is a curve for the yield stress versus the +effective strain rate. Optionally, Young’s modulus and the tangent modulus can also be +defined versus the effective strain rate. Also, optional failure of the material can be +defined either by defining a von Mises stress at failure as a function of the effective +strain rate (valid for solids/shells/thick shells) or by defining a minimum time step size +(only for shells). + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +VP +F +Default +none +none +none +none +0.0 +6 +7 +8 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LC1 +ETAN +LC2 +LC3 +LC4 +TDEL +RDEF +Type +F +F +F +F +F +F +F +Default +none +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +VP +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +Formulation for rate effects: +EQ.0.0: Scale yield stress (default), +EQ.1.0: Viscoplastic formulation +LC1 +ETAN +LC2 +LC3 +LC4 +TDEL +*MAT_STRAIN_RATE_DEPENDENT_PLASTICITY +DESCRIPTION +Load curve ID defining the yield stress σ0 as a function of the +effective strain rate. +Tangent modulus, Et +Load curve ID defining Young’s modulus as a function of the +effective +(available only when VP = 0; not +strain +recommended). +rate +Load curve ID defining tangent modulus as a function of the +effective strain rate (optional). +Load curve ID defining von Mises stress at failure as a function of +the effective strain rate (optional). +Minimum time step size for automatic element deletion. Use for +shells only. +RDEF +Redefinition of failure curve: +EQ.1.0: Effective plastic strain, +EQ.2.0: Maximum principal stress and absolute value of +minimum principal stress, +EQ.3.0: Maximum principal stress (release 5 of v.971) +Remarks: +In this model, a load curve is used to describe the yield strength 𝜎0 as a function of +effective strain rate 𝜀̅ +̇ where +𝜀̅ +̇ = ( +2⁄ +′ ) +′ 𝜀̇𝑖𝑗 +𝜀̇𝑖𝑗 +and the prime denotes the deviatoric component. The strain rate is available for post- +processing as the first stored history variable. If the viscoplastic option is active, the +plastic strain rate is output; otherwise, the effective strain rate defined above is output. +The yield stress is defined as +𝜎𝑦 = 𝜎0(𝜀̅ +̇) + 𝐸𝑝𝜀̅𝑝 +where 𝜀̅𝑝 is the effective plastic strain and 𝐸𝑝 is given in terms of Young’s modulus and +the tangent modulus by +𝐸𝑝 = +𝐸𝐸𝑡 +𝐸 − 𝐸𝑡 +. +Both Young's modulus and the tangent modulus may optionally be made functions of +strain rate by specifying a load curve ID giving their values as a function of strain rate. +If these load curve ID's are input as 0, then the constant values specified in the input are +used. +Note that all load curves used to define quantities as a function of strain rate must have +the same number of points at the same strain rate values. This requirement is used to +allow vectorized interpolation to enhance the execution speed of this constitutive +model. +This model also contains a simple mechanism for modeling material failure. This +option is activated by specifying a load curve ID defining the effective stress at failure +as a function of strain rate. For solid elements, once the effective stress exceeds the +failure stress the element is deemed to have failed and is removed from the solution. +For shell elements the entire shell element is deemed to have failed if all integration +points through the thickness have an effective stress that exceeds the failure stress. +After failure the shell element is removed from the solution. +In addition to the above failure criterion, this material model also supports a shell +element deletion criterion based on the maximum stable time step size for the element, +Δ𝑡max. Generally, Δ𝑡max goes down as the element becomes more distorted. To assure +stability of time integration, the global LS-DYNA time step is the minimum of the Δ𝑡max +values calculated for all elements in the model. Using this option allows the selective +deletion of elements whose time step Δ𝑡max has fallen below the specified minimum +time step, Δ𝑡crit. Elements which are severely distorted often indicate that material has +failed and supports little load, but these same elements may have very small time steps +and therefore control the cost of the analysis. This option allows these highly distorted +elements to be deleted from the calculation, and, therefore, the analysis can proceed at a +larger time step, and, thus, at a reduced cost. Deleted elements do not carry any load, +and are deleted from all applicable slide surface definitions. Clearly, this option must +be judiciously used to obtain accurate results at a minimum cost. +A fully viscoplastic formulation is optional which incorporates the rate formulation +within the yield surface. An additional cost is incurred but the improvement is results +can be dramatic. +*MAT_RIGID +This is Material 20. Parts made from this material are considered to belong to a rigid +body (for each part ID). Also, the coupling of a rigid body with MADYMO and CAL3D +can be defined via this material. Alternatively, a VDA surface can be attached as +surface to model the geometry, e.g., for the tooling in metalforming applications. Also, +global and local constraints on the mass center can be optionally defined. Optionally, a +local consideration for output and user-defined airbag sensors can be chosen. +5 +N +F +0 +5 + Card 1 +1 +2 +Variable +MID +RO +Type +A8 +F +3 +E +F +4 +PR +F +Default +none +none +none +none + Card 2 +1 +2 +3 +4 +Variable +CMO +CON1 +CON2 +Type +Default +F +0 +F +0 +F +0 +Optional for output (Must be included but may be left blank). + Card 3 +1 +2 +Variable LCO or A1 +A2 +Type +Default +F +0 +F +0 +3 +A3 +F +0 +4 +V1 +F +0 +5 +V2 +F +0 +7 +M +F +0 +7 +8 +ALIAS or +RE +C/F +blank +none +8 +7 +8 +6 +COUPLE +F +0 +6 +6 +V3 +F +MID +RO +E +PR +N +*MAT_020 +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus. Reasonable values have to be chosen for +contact analysis (choice of penalty), see Remarks below. +Poisson’s ratio. Reasonable values have to be chosen for contact +analysis (choice of penalty), see Remarks below. +MADYMO3D 5.4 coupling flag, n: +EQ.0: use normal LS-DYNA rigid body updates, +GT.0: the rigid body is coupled to MADYMO 5.4 ellipsoid +number n +LT.0: the rigid body is coupled to MADYMO 5.4 plane number +|n|. +COUPLE +Coupling option if applicable: +EQ.-1: attach VDA surface in ALIAS (defined in the eighth +field) and automatically generate a mesh for viewing +the surface in LS-PREPOST. +MADYMO 5.4 / CAL3D coupling option: +EQ.0: the undeformed geometry +to LS-DYNA +corresponds to the local system for MADYMO 5.4 / +CAL3D. The finite element mesh is input, +input +EQ.1: the undeformed geometry +to LS-DYNA +corresponds to the global system for MADYMO 5.4 / +CAL3D, +input +EQ.2: generate a mesh for the ellipsoids and planes internally +in LS-DYNA. +M +MADYMO3D 5.4 coupling flag, m: +EQ.0: use normal LS-DYNA rigid body updates, +EQ.m: this rigid body corresponds to MADYMO rigid body +number m. Rigid body updates are performed by +MADYMO. +ALIAS +VDA surface alias name, see Appendix L. +RE +CMO +DESCRIPTION +MADYMO 6.0.1 External Reference Number +Center of mass constraint option, CMO: +EQ.+1.0: constraints applied in global directions, +EQ.0.0: no constraints, +*MAT_RIGID +EQ.-1.0: constraints +constraint). +applied +in +local directions +(SPC +CON1 +First constraint parameter: +If CMO = +1.0, then specify global translational constraint: +EQ.0: no constraints, +EQ.1: constrained x displacement, +EQ.2: constrained y displacement, +EQ.3: constrained z displacement, +EQ.4: constrained x and y displacements, +EQ.5: constrained y and z displacements, +EQ.6: constrained z and x displacements, +EQ.7: constrained x, y, and z displacements. +If CM0 = -1.0, then specify local coordinate system ID. +See *DEFINE_COORDINATE_OPTION: This coordinate +system is fixed in time. +CON2 +Second constraint parameter: +If CMO = +1.0, then specify global rotational constraint: +EQ.0: no constraints, +EQ.1: constrained x rotation, +EQ.2: constrained y rotation, +EQ.3: constrained z rotation, +EQ.4: constrained x and y rotations, +EQ.5: constrained y and z rotations, +EQ.6: constrained z and x rotations, +EQ.7: constrained x, y, and z rotations. +VARIABLE +DESCRIPTION +If CM0 = -1.0, then specify local (SPC) constraint: +EQ.000000: no constraint, +EQ.100000: constrained x translation, +EQ.010000: constrained y translation, +EQ.001000: constrained z translation, +EQ.000100: constrained x rotation, +EQ.000010: constrained y rotation, +EQ.000001: constrained z rotation. +Any combination of local constraints can be achieved by adding +the number 1 into the corresponding column. +LCO +Local coordinate system number for output. +A1 - V3 +Alternative method for specifying local system below: +Define two vectors a and v, fixed in the rigid body which are +used for output and the user defined airbag sensor subrou- +tines. The output parameters are in the directions a, b, and c +where the latter are given by the cross products c = a × v and +b = c × a. This input is optional. +Remarks: +The rigid material type 20 provides a convenient way of turning one or more parts +comprised of beams, shells, or solid elements into a rigid body. Approximating a +deformable body as rigid is a preferred modeling technique in many real world +applications. For example, in sheet metal forming problems the tooling can properly +and accurately be treated as rigid. In the design of restraint systems the occupant can, +for the purposes of early design studies, also be treated as rigid. Elements which are +rigid are bypassed in the element processing and no storage is allocated for storing +history variables; consequently, the rigid material type is very cost efficient. +Two unique rigid part ID's may not share common nodes unless they are merged +together using the rigid body merge option. A rigid body may be made up of disjoint +finite element meshes, however. LS-DYNA assumes this is the case since this is a +common practice in setting up tooling meshes in forming problems. +All elements which reference a given part ID corresponding to the rigid material should +be contiguous, but this is not a requirement. If two disjoint groups of elements on +opposite sides of a model are modeled as rigid, separate part ID's should be created for +each of the contiguous element groups if each group is to move independently. This +requirement arises from the fact that LS-DYNA internally computes the six rigid body +degrees-of-freedom for each rigid body (rigid material or set of merged materials), and +if disjoint groups of rigid elements use the same part ID, the disjoint groups will move +together as one rigid body. +Inertial properties for rigid materials may be defined in either of two ways. By default, +the inertial properties are calculated from the geometry of the constituent elements of +the rigid material and the density specified for the part ID. Alternatively, the inertial +properties and initial velocities for a rigid body may be directly defined, and this +overrides data calculated from the material property definition and nodal initial +velocity definitions. +Young's modulus, E, and Poisson's ratio, υ are used for determining sliding interface +parameters if the rigid body interacts in a contact definition. Realistic values for these +constants should be defined since unrealistic values may contribute to numerical +problem in contact. +Constraint directions for rigid materials (CMO equal to +1 or -1) are fixed, that is, not +updated, with time. To impose a constraint on a rigid body such that the constraint +direction is updated as the rigid body rotates, use *BOUNDARY_PRESCRIBED_MO- +TION_RIGID_LOCAL. +It is strongly advised that nodal constraints, e.g., by *BOUNDARY_SPC_OPTION, not +be applied to nodes of a rigid body as doing so may compromise the intended +constraints in the case of an explicit simulation. Such SPCs will be skipped in an +implicit simulation and a warning issued. +If the intended constraints are not with respect to the calculated center-of-mass of the +rigid body, *CONSTRAINED_JOINT_OPTION may often be used to obtain the desired +effect. This approach typically entails defining a second rigid body which is fully +constrained and then defining a joint between the two rigid bodies. Another alternative +for defining rigid body constraints that are not with respect to the calculated center-of- +mass of the rigid body is to manually specify the initial center-of-mass location using +*PART_INERTIA. When using *PART_INERTIA, a full set of mass properties must be +specified and the user must understand that the dynamic behavior of the rigid body is +affected by its mass properties. +For coupling with MADYMO 5.4.1, only basic coupling is available. +The coupling flags (N and M) must match with SYSTEM and ELLIP- +SOID/PLANE in the MADYMO input file and the coupling option (COUPLE) +must be defined. +For coupling with MADYMO 6.0.1, both basic and extended coupling are available: +1. Basic Coupling: The external reference number (RE) must match with the +external reference number in the MADYMO XML input file. The coupling +option (COUPLE) must be defined. +2. Extended Coupling: Under this option MADYMO will handle the contact +between the MADYMO and LS-DYNA models. The external reference number +(RE) and the coupling option (COUPLE) are not needed. All coupling surfaces +that interface with the MADYMO models need to be defined in *CONTACT_- +COUPLING. +*MAT_ORTHOTROPIC_THERMAL_{OPTION} +This is Material Type 21. A linearly elastic, orthotropic material with orthotropic +thermal expansion. +Available options include: + +FAILURE +CURING + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +EA +F +3 +Variable +GAB +GBC +GCA +Type +F +F +F + Card 3 +Variable +1 +XP +Type +F + Card 4 +Variable +1 +V1 +Type +F +2 +YP +F +2 +V2 +F +3 +ZP +F +3 +V3 +F +4 +EB +F +4 +AA +F +4 +A1 +F +4 +D1 +F +5 +EC +F +5 +AB +F +5 +A2 +F +5 +D2 +F +6 +7 +8 +PRBA +PRCA +PRCB +F +6 +AC +F +6 +A3 +F +6 +D3 +F +F +7 +F +8 +AOPT +MACF +F +7 +I +8 +7 +8 +BETA +REF +Required for failure. + Card 5 +Variable +1 +A1 +2 +A11 +Type +F +F +3 +A2 +F +Additional card 5 required for curing. + Card 5 +Variable +1 +K1 +Type +F +2 +K2 +F +3 +C1 +F +Additional card 6 required for curing. +4 +A5 +F +4 +C2 +F +5 +A55 +F +5 +M +F +6 +A4 +F +6 +N +F +7 +NIP +F +7 +R +F +8 +8 + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCCHA +LCCHB +LCCHC +LCAA +LCAB +LCAC +Type +I +I +I +I +I +I + VARIABLE +DESCRIPTION +MID +RO +EA +EB +EC +PRBA +PRCA +PRCB +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +𝐸𝑎, Young’s modulus in 𝑎-direction. +𝐸𝑏, Young’s modulus in 𝑏-direction. +𝐸𝑐, Young’s modulus in 𝑐-direction. +𝜈𝑏𝑎, Poisson’s ratio, 𝑏𝑎. +𝜈𝑐𝑎, Poisson’s ratio, 𝑐𝑎. +𝜈𝑐𝑏, Poisson’s ratio, 𝑐𝑏 +*MAT_ORTHOTROPIC_THERMAL +DESCRIPTION +GAB +GBC +GCA +AA +AB +AC +AOPT +𝐺𝑎𝑏, Shear modulus, 𝑎𝑏. +𝐺𝑏𝑐, Shear modulus, 𝑏𝑐. +𝐺𝑐𝑎, Shear modulus, 𝑐𝑎. +𝛼𝑎, coefficient of thermal expansion in the 𝑎-direction. +𝛼𝑏, coefficient of thermal expansion in the 𝑏-direction. +𝛼𝑐, coefficient of thermal expansion in the 𝑐-direction. +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then, for shells only, rotated about +the shell element normal by an angle BETA. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the a-direction. This option is for solid +elements only. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector 𝐯, and +an originating point, 𝐩, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +VARIABLE +DESCRIPTION +MACF +Material axes change flag for brick elements: +EQ.1: No change, default, +EQ.2: switch material axes a and b, +EQ.3: switch material axes a and c, +EQ.4: switch material axes b and c. +XP, YP, ZP +Coordinates of point 𝐩 for AOPT = 1 and 4. +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3 and 4. +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2. +BETA +REF +Material angle in degrees for AOPT = 1 (shells only) and +AOPT = 3, may be overridden on the element card, see *ELE- +MENT_SHELL_BETA or *ELEMENT_SOLID_ORTHO. +Use reference geometry to initialize the stress tensor. The +reference geometry is defined by the keyword:*INITIAL_FOAM_- +REFERENCE_GEOMETRY . +EQ.0.0: off, +EQ.1.0: on. +A1, A11, A2 +A5, A55, A4 +Coefficients for the matrix dominated failure criterion. +Coefficients for the fiber dominated failure criterion. +K1 +K2 +C1 +C2 +M +N +R +Parameter 𝑘1 for Kamal model. For details see remark below. +Parameter 𝑘2 for Kamal model. +Parameter 𝑐1 for Kamal model. +Parameter 𝑐2 for Kamal model. +Exponent 𝑚 for Kamal model. +Exponent 𝑛 for Kamal model. +Gas constant for Kamal model. +LCCHA +LCCHB +LCCHC +LCAA +*MAT_ORTHOTROPIC_THERMAL +DESCRIPTION +Load curve for 𝛾𝑎, coefficient of chemical shrinkage in the 𝑎- +direction. Input 𝛾𝑎 as function of state of cure 𝛽. +Load curve for 𝛾𝑏, coefficient of chemical shrinkage in the 𝑏- +direction. Input 𝛾𝑏 as function of state of cure 𝛽. +Load curve for 𝛾𝑐, coefficient of chemical shrinkage in the 𝑐- +direction. Input 𝛾𝑐 as function of state of cure 𝛽. +Load curve or table ID for 𝛼𝑎. If defined parameter AA is +ignored. +IF LCID +Input 𝛼𝑎 versus temperature. +IF TABID: +Input 𝛼𝑎 as functions of state of cure (table values) and +temperatures +Load curve ID for 𝛼𝑏. If defined parameter AB is ignored. See +LCAA for further details. +Load curve ID for 𝛼𝑐. If defined parameter AC is ignored. See +LCAA for further details. +LCAB +LCAC +Remarks: +In the implementation for three-dimensional continua a total Lagrangian formulation is +used. In this approach the material law that relates second Piola-Kirchhoff stress 𝐒 to +the Green-St. Venant strain 𝐄 is +where 𝐓 is the transformation matrix [Cook 1974]. +𝐒 = 𝐂 ⋅ 𝐄 = 𝐓T𝐂𝑙𝐓 ⋅ 𝐄 +𝐓 = +𝑙1 +𝑙2 +𝑙3 +2𝑙1𝑙2 +2𝑙2𝑙3 +2𝑙3𝑙1 +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +𝑚1 +𝑚2 +𝑚3 +2𝑚1𝑚2 +2𝑚2𝑚3 +2𝑚3𝑚1 +𝑛1 +𝑛2 +𝑚3 +2𝑛1𝑛2 +2𝑛2𝑛3 +2𝑛3𝑛1 +𝑙1𝑚1 +𝑙2𝑚2 +𝑙3𝑚3 +(𝑙1𝑚2 + 𝑙2𝑚1) +(𝑙2𝑚3 + 𝑙3𝑚2) +(𝑙3𝑚1 + 𝑙1𝑚3) +𝑚1𝑛1 +𝑚2𝑛2 +𝑚3𝑛3 +(𝑚1𝑛2 + 𝑚2𝑛1) +(𝑚2𝑛3 + 𝑚3𝑛2) +(𝑚3𝑛1 + 𝑚1𝑛3) +𝑛1𝑙1 +⎤ +⎥ +𝑛2𝑙2 +⎥ +⎥ +𝑛3𝑙3 +⎥ +⎥ +(𝑛1𝑙2 + 𝑛2𝑙1) +⎥ +(𝑛2𝑙3 + 𝑛3𝑙2) +⎥ +(𝑛3𝑙1 + 𝑛1𝑙3)⎦ +𝑙𝑖, 𝑚𝑖, 𝑛𝑖 are the direction cosines +′ = 𝑙𝑖𝑥1 + 𝑚𝑖𝑥2 + 𝑛𝑖𝑥3 for 𝑖 = 1, 2, 3 +𝑥𝑖 +′ denotes the material axes. The constitutive matrix 𝐂𝑙 is defined in terms of the +and 𝑥𝑖 +material axes as +−1 = +𝐂𝑙 +𝐸11 +𝜐12 +𝐸11 +𝜐13 +𝐸11 +− +− +− +𝜐21 +𝐸22 +𝐸22 +𝜐23 +𝐸22 +− +− +− +𝜐31 +𝐸33 +𝜐32 +𝐸33 +𝐸33 +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +𝐺12 +𝐺23 +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +𝐺31 ⎦ +where the subscripts denote the material axes, i.e., +′ +′ and 𝐸𝑖𝑖 = 𝐸𝑥𝑖 +𝜐𝑖𝑗 = 𝜐𝑥𝑖 +′𝑥𝑗 +Since 𝐂𝑙 is symmetric +𝜐12 +𝐸11 += +𝜐21 +𝐸22 +, … +The vector of Green-St. Venant strain components is +𝐄T = [𝐸11, 𝐸22, 𝐸33, 𝐸12, 𝐸23, 𝐸31] +which include the local thermal strains which are integrated in time: +𝑛+1 = 𝜀𝑎𝑎 +𝜀𝑎𝑎 +𝑛+1 = 𝜀𝑏𝑏 +𝜀𝑏𝑏 +𝑛+1 = 𝜀𝑐𝑐 +𝜀𝑐𝑐 +𝑛 + 𝛼𝑎(𝑇𝑛+1 − 𝑇𝑛) +𝑛 + 𝛼𝑏(𝑇𝑛+1 − 𝑇𝑛) +𝑛 + 𝛼𝑐(𝑇𝑛+1 − 𝑇𝑛) +where 𝑇 is temperature. After computing 𝑆𝑖𝑗 we then obtain the Cauchy stress: +𝜎𝑖𝑗 = +𝜌0 +∂𝑥𝑖 +∂𝑋𝑘 +∂𝑥𝑗 +∂𝑋𝑙 +𝑆𝑘𝑙 +This model will predict realistic behavior for finite displacement and rotations as long +as the strains are small. +In the implementation for shell elements, the stresses are integrated in time and are +updated in the corotational coordinate system. In this procedure the local material axes +are assumed to remain orthogonal in the deformed configuration. This assumption is +valid if the strains remain small. +The failure models were derived by William Feng. The first one defines the matrix +dominated failure mode, +𝐹𝑚 = 𝐴1(𝐼1 − 3) + 𝐴11(𝐼1 − 3)2 + 𝐴2(𝐼2 − 3) − 1 +and the second defines the fiber dominated failure mode, +𝐹𝑓 = 𝐴5(𝐼5 − 1) + 𝐴55(𝐼5 − 1)2 + 𝐴4(𝐼4 − 1) − 1. +When either is greater than zero, the integration point fails, and the element is deleted +after NIP integration points fail. +The coefficients 𝐴𝑖 are defined in the input and the invariants 𝐼𝑖 are the strain invariants +𝐼1 = ∑ 𝐶𝛼𝛼 +𝛼=1,3 +𝐼2 = +[𝐼1 +2 − ∑ 𝐶𝛼𝛽 +𝛼,𝛽=1,3 +] +𝐼3 = det(𝐂) +𝐼4 = ∑ 𝑉𝛼 +𝛼,𝛽,𝛾=1,3 +𝐶𝛼𝛾𝐶𝛾𝛽𝑉𝛽 +𝐼5 = ∑ 𝑉𝛼 +𝛼,𝛽=1,3 +𝐶𝛼𝛽𝑉𝛽 +and 𝐂 is the Cauchy strain tensor and 𝐕 is the fiber direction in the undeformed state. +By convention in this material model, the fiber direction is aligned with the 𝑎 direction +of the local orthotropic coordinate system. +The curing option implies that orthotropic chemical shrinkage is to be considered, +resulting from a curing process in the material. The state of cure 𝛽 is an internal +material variable that follows the Kamal model += (𝐾1 + 𝐾2𝛽𝑚)(1 − 𝛽)𝑛 with 𝐾1 = 𝑘1𝑒 +− +𝑐1 +𝑅𝑇, 𝐾2 = 𝑘2𝑒 +− +𝑐2 +𝑅𝑇 +𝑑𝛽 +𝑑𝑡 +and chemical strains are introduced: +𝑛+1 = 𝜀𝑎𝑎 +𝜀𝑎𝑎 +𝑛+1 = 𝜀𝑏𝑏 +𝜀𝑏𝑏 +𝑛+1 = 𝜀𝑐𝑐 +𝜀𝑐𝑐 +𝑛 + 𝛾𝑎(𝛽𝑛+1 − 𝛽𝑛) +𝑛 + 𝛾𝑏(𝛽𝑛+1 − 𝛽𝑛) +𝑛 + 𝛾𝑐(𝛽𝑛+1 − 𝛽𝑛) +The coefficients 𝛾𝑎, 𝛾𝑏, 𝛾𝑐 can be defined as functions of the state of cure 𝛽. Furthermore, +the coefficients of thermal expansion 𝛼𝑎, 𝛼𝑏, 𝛼𝑐can also be defined as functions of the +state of cure 𝛽 and the temperature 𝑇, if the curing option is used. +*MAT_022 +This is Material Type 22. An orthotropic material with optional brittle failure for +composites can be defined following the suggestion of [Chang and Chang 1987a, +1987b]. Three failure criteria are possible, see the LS-DYNA Theory Manual. By using +the user defined integration rule, see *INTEGRATION_SHELL, the constitutive +constants can vary through the shell thickness. +For all shells, except the DKT formulation, laminated shell theory can be activated to +properly model the transverse shear deformation. Lamination theory is applied to +correct for the assumption of a uniform constant shear strain through the thickness of +the shell. For sandwich shells where the outer layers are much stiffer than the inner +layers, the response will tend to be too stiff unless lamination theory is used. To turn on +lamination theory see *CONTROL_SHELL. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +EA +F +4 +EB +F +5 +EC +F +6 +7 +8 +PRBA +PRCA +PRCB +F +F +F +Default +none +none +none +none +none +none +none +none + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +GAB +GBC +GCA +KFAIL +AOPT +MACF +ATRACK +Type +F +F +F +F +F +Default +none +none +none +0.0 +0.0 +I +0 +I +Variable +1 +XP +Type +F +*MAT_COMPOSITE_DAMAGE +2 +YP +F +3 +ZP +F +4 +A1 +F +5 +A2 +F +6 +A3 +F +7 +8 +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 4 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +BETA +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 5 +Variable +1 +SC +Type +F +2 +XT +F +3 +YT +F +4 +YC +F +5 +ALPH +F +6 +SN +F +7 +8 +SYZ +SZX +F +F +Default +none +none +none +none +none +none +none +none + VARIABLE +DESCRIPTION +MID +RO +EA +EB +EC +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +𝐸𝑎, Young’s modulus in 𝑎-direction. +𝐸𝑏, Young’s modulus in 𝑏-direction. +𝐸𝑐, Young’s modulus in 𝑐-direction. +PRBA +𝜈𝑏𝑎, Poisson ratio, 𝑏𝑎. +VARIABLE +DESCRIPTION +PRCA +PRCB +GAB +GBC +GCA +KFAIL +AOPT +𝜈𝑐𝑎, Poisson ratio, 𝑐𝑎. +𝜈𝑐𝑏, Poisson ratio, 𝑐𝑏. +𝐺𝑎𝑏, Shear modulus, 𝑎𝑏. +𝐺𝑏𝑐, Shear modulus, 𝑏𝑐. +𝐺𝑐𝑎, Shear modulus, 𝑐𝑎. +Bulk modulus of failed material. Necessary for compressive +failure. +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then, for shells only, rotated about +the shell element normal by an angle BETA. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the 𝑎-direction. This option is for solid +elements only. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector 𝐯, and +an originating point, 𝐩, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +*MAT_COMPOSITE_DAMAGE +DESCRIPTION +MACF +Material axes change flag for brick elements: +EQ.1: No change, default, +EQ.2: switch material axes 𝑎 and 𝑏, +EQ.3: switch material axes 𝑎 and 𝑐, +EQ.4: switch material axes 𝑏 and 𝑐. +ATRACK +Material a-axis tracking flag (shell elements only) +EQ.0: a-axis rotates with element (default) +EQ.1: a-axis also tracks deformation +XP, YP, ZP +Coordinates of point 𝐩 for AOPT = 1 and 4. +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3 and 4. +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2. +Material angle in degrees for AOPT = 0 (shells only) and +AOPT = 3, may be overridden on the element card, see *ELE- +MENT_SHELL_BETA or *ELEMENT_SOLID_ORTHO. +Shear strength, ab plane, see the LS-DYNA Theory Manual. +Longitudinal tensile strength, 𝑎-axis, see the LS-DYNA Theory +Manual. +Transverse tensile strength, 𝑏-axis. +Transverse compressive strength, 𝑏-axis (positive value). +Shear stress parameter for the nonlinear term, see the LS-DYNA +Theory Manual. Suggested range 0 – 0.5. +Normal tensile strength (solid elements only) +Transverse shear strength (solid elements only) +Transverse shear strength (solid elements only) +BETA +SC +XT +YT +YC +ALPH +SN +SYZ +SZX +Remarks: +1. History Data. The number of additional integration point variables for shells +written to the d3plot database is specified using the *DATABASE_EXTENT_BI- +NARY keyword on the NEIPS field. These additional history variables are +enumerated below: +History Variable3 +Description +Value +ef(𝑖) +tensile fiber mode +LS-PrePost +history variable +See +below +table +cm(𝑖) +ed(𝑖) +tensile matrix mode +compressive +mode +matrix +1 - elastic +0 - failed +1 +2 +The following components are stored as element component 7 instead of the +effective plastic strain. Note that ef(𝑖) for 𝑖 = 1,2,3 is not retrievable. +Description +Integration point +nip +nip +∑ ef(𝑖) +𝑖=1 +nip +nip +∑ cm(𝑖) +𝑖=1 +nip +nip +∑ ed(𝑖) +𝑖=1 +ef(𝑖) for 𝑖 > 3 +1 +2 +3 +𝑖 +2. The ATRACK Field. The initial material directions are set using AOPT and the +related data. By default, the material directions in shell elements are updated +each cycle based on the rotation of the 1-2 edge, or else the rotation of all edges +if the invariant node numbering option is set on *CONTROL_ACCURACY. +When ATRACK=1, an optional scheme is used in which the 𝑎-direction of the +material tracks element deformation as well as rotation. +At the start of the calculation, a line is passed through each element center in +the direction of the material a-axis. This line will intersect the edges of the +element at two points. The referential coordinates of these two points are +stored, and then used throughout the calculation to locate these points in the +deformed geometry. The material 𝑎-axis is assumed to be in the direction of the +line that passes through both points. If ATRACK = 0, the layers of a layered +3 (cid:1861) ranges over the shell integration points. +composite will always rotate together. However, if ATRACK = 1, the layers can +rotate independently which may be more accurate, particularly for shear de- +formation. This option is available only for shell elements. +*MAT_TEMPERATURE_DEPENDENT_ORTHOTROPIC +This is Material Type 23. An orthotropic elastic material with arbitrary temperature +dependency can be defined. + Card 1 +1 +Variable +MID +2 +RO +3 +4 +5 +6 +7 +8 +AOPT +REF +MACF +Type +A8 +F +F +F +I + Card 2 +Variable +1 +XP +Type +F + Card 3 +Variable +1 +V1 +Type +F +2 +YP +F +2 +V2 +F +3 +ZP +F +3 +V3 +F +4 +A1 +F +4 +D1 +F +5 +A2 +F +5 +D2 +F +6 +A3 +F +6 +D3 +F +7 +8 +7 +8 +BETA +F +Temperature Card Pairs. Define one set of constants on two cards using formats 4 +and 5 for each temperature point. Up to 48 points (96 cards) can be defined. The next +“*” card terminates the input. +First Temperature Card. + Card 4 +1 +Variable +EAi +2 +EBi +3 +4 +5 +6 +7 +8 +ECi +PRBAi +PRCAi +PRCBi +Type +F +F +F +F +F +Second Temperature Card + Card 5 +1 +Variable +AAi +2 +ABi +3 +4 +5 +6 +ACi +GABi +GBCi +GCAi +Type +F +F +F +F +F +F +8 +7 +Ti +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +AOPT +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then, for shells only, rotated about +the shell element normal by an angle BETA. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the 𝑎-direction. This option is for solid +elements only. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector 𝐯 with the +element normal. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector 𝐯, and +an originating point, 𝐩, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +VARIABLE +DESCRIPTION +and later. +REF +Use reference geometry to initialize the stress tensor. The +reference geometry is defined by the keyword:*INITIAL_FOAM_- +REFERENCE_GEOMETRY . +EQ.0.0: off, +EQ.1.0: on. +MACF +Material axes change flag for brick elements: +EQ.1: No change, default, +EQ.2: switch material axes 𝑎 and 𝑏, +EQ.3: switch material axes 𝑎 and 𝑐, +EQ.4: switch material axes 𝑏 and 𝑐. +XP, YP, ZP +Coordinates of point 𝐩 for AOPT = 1 and 4. +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3 and 4. +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2. +BETA +EAi +EBi +ECi +PRBAi +PRCAi +PRCBi +AAi +ABi +Material angle in degrees for AOPT = 0 (shells only) and +AOPT = 3, may be overridden on the element card, see *ELE- +MENT_SHELL_BETA or *ELEMENT_SOLID_ORTHO. +𝐸𝑎, Young’s modulus in 𝑎-direction at temperature Ti. +𝐸𝑏, Young’s modulus in 𝑏-direction at temperature Ti. +𝐸𝑐, Young’s modulus in 𝑐-direction at temperature Ti. +𝜈𝑏𝑎, Poisson’s ratio 𝑏𝑎 at temperature Ti. +𝜈𝑐𝑎, Poisson’s ratio 𝑐𝑎 at temperature Ti. +𝜈𝑐𝑏, Poisson’s ratio 𝑐𝑏 at temperature Ti. +𝛼𝑎, coefficient of thermal expansion in 𝑎-direction at temperature +Ti. +𝛼𝐵 coefficient of thermal expansion in 𝑏-direction at temperature +Ti. +𝛼𝑐, coefficient of thermal expansion in 𝑐-direction at temperature +Ti. +𝐺𝑎𝑏, Shear modulus 𝑎𝑏 at temperature Ti. +𝐺𝑏𝑐, Shear modulus 𝑏𝑐 at temperature Ti. +𝐺𝑐𝑎, Shear modulus 𝑐𝑎 at temperature Ti. +ith temperature +*MAT_023 + VARIABLE +ACi +GABi +GBCi +GCAi +Ti +Remarks: +In the implementation for three-dimensional continua a total Lagrangian formulation is +used. In this approach the material law that relates second Piola-Kirchhoff stress 𝐒 to +the Green-St. Venant strain 𝐄 is +where 𝐓 is the transformation matrix [Cook 1974]. +𝐒 = 𝐂 ⋅ 𝐄 = 𝐓T𝐂𝒍𝐓 ⋅ 𝐄 +𝐓 = +𝑙1 +𝑙2 +𝑙3 +2𝑙1𝑙2 +2𝑙2𝑙3 +2𝑙3𝑙1 +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +𝑚1 +𝑚2 +𝑚3 +2𝑚1𝑚2 +2𝑚2𝑚3 +2𝑚3𝑚1 +𝑛1 +𝑛2 +𝑚3 +2𝑛1𝑛2 +2𝑛2𝑛3 +2𝑛3𝑛1 +𝑙1𝑚1 +𝑙2𝑚2 +𝑙3𝑚3 +(𝑙1𝑚2 + 𝑙2𝑚1) +(𝑙2𝑚3 + 𝑙3𝑚2) +(𝑙3𝑚1 + 𝑙1𝑚3) +𝑚1𝑛1 +𝑚2𝑛2 +𝑚3𝑛3 +(𝑚1𝑛2 + 𝑚2𝑛1) +(𝑚2𝑛3 + 𝑚3𝑛2) +(𝑚3𝑛1 + 𝑚1𝑛3) +𝑛1𝑙1 +⎤ +⎥ +𝑛2𝑙2 +⎥ +⎥ +𝑛3𝑙3 +⎥ +⎥ +(𝑛1𝑙2 + 𝑛2𝑙1) +⎥ +(𝑛2𝑙3 + 𝑛3𝑙2) +⎥ +(𝑛3𝑙1 + 𝑛1𝑙3)⎦ +𝑙𝑖, 𝑚𝑖, 𝑛𝑖 are the direction cosines +′ = 𝑙𝑖𝑥1 + 𝑚𝑖𝑥2 + 𝑛𝑖𝑥3 for 𝑖 = 1, 2, 3 +𝑥𝑖 +′ denotes the material axes. The temperature dependent constitutive matrix 𝐂𝑙 is +and 𝑥𝑖 +defined in terms of the material axes as +𝐸11(𝑇) +𝜐12(𝑇) +𝐸11(𝑇) +𝜐13(𝑇) +𝐸11(𝑇) +− +− +− +𝜐21(𝑇) +𝐸22(𝑇) +𝐸22(𝑇) +𝜐23(𝑇) +𝐸22(𝑇) +− +− +− +𝜐31(𝑇) +𝐸33(𝑇) +𝜐32(𝑇) +𝐸33(𝑇) +𝐸33(𝑇) +−1 = +𝐂𝑙 +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +𝐺12(𝑇) +𝐺23(𝑇) +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +𝐺31(𝑇) ⎦ +where the subscripts denote the material axes, i.e., +′ +′ and 𝐸𝑖𝑖 = 𝐸𝑥𝑖 +𝜐𝑖𝑗 = 𝜐𝑥𝑖 +′𝑥𝑗 +Since 𝐂𝑙 is symmetric +𝜐12 +𝐸11 += +𝜐21 +𝐸22 +, … +The vector of Green-St. Venant strain components is +𝐄T = ⌊𝐸11, 𝐸22, 𝐸33, 𝐸12, 𝐸23, 𝐸31⌋ +which include the local thermal strains which are integrated in time: +𝑛+1 = 𝜀𝑎𝑎 +𝜀𝑎𝑎 +𝑛 + 𝛼𝑎 (𝑇 +𝑛+1 +2) [𝑇𝑛+1 − 𝑇𝑛] +𝑛+1 = 𝜀𝑏𝑏 +𝜀𝑏𝑏 +𝑛 + 𝛼𝑏 (𝑇 +𝑛+1 +2) [𝑇𝑛+1 − 𝑇𝑛] +𝑛+1 = 𝜀𝑐𝑐 +𝜀𝑐𝑐 +𝑛 + 𝛼𝑐 (𝑇 +𝑛+1 +2) [𝑇𝑛+1 − 𝑇𝑛] +where 𝑇 is temperature. After computing 𝑆𝑖𝑗 we then obtain the Cauchy stress: +𝜎𝑖𝑗 = +𝜌0 +∂𝑥𝑖 +∂𝑋𝑘 +∂𝑥𝑗 +∂𝑋𝑙 +𝑆𝑘𝑙 +This model will predict realistic behavior for finite displacement and rotations as long +as the strains are small. +For shell elements, the stresses are integrated in time and are updated in the +corotational coordinate system. In this procedure the local material axes are assumed to +remain orthogonal in the deformed configuration. This assumption is valid if the +strains remain small. +*MAT_PIECEWISE_LINEAR_PLASTICITY_{OPTION} +Available options include: + +LOG_INTERPOLATION +STOCHASTIC +MIDFAIL +This is Material Type 24, which is an elasto-plastic material with an arbitrary stress +versus strain curve and arbitrary strain rate dependency can be defined. See also +Remark below. Also, failure based on a plastic strain or a minimum time step size can +be defined. For another model with a more comprehensive failure criteria see MAT_ +MODIFIED_PIECEWISE_LINEAR_PLASTICITY. If considering laminated or sandwich +shells with non-uniform material properties (this is defined through the user specified +integration rule), the model, MAT_LAYERED_LINEAR_PLASTICITY, is recommended. +If solid elements are used and if the elastic strains before yielding are finite, the model, +MAT_FINITE_ELASTIC_STRAIN_PLASTICITY, treats the elastic strains using a +hyperelastic formulation. +The LOG_INTERPOLATION option interpolates the strain rate effect in table LCSS +with logarithmic interpolation. +The STOCHASTIC option allows spatially varying yield and failure behavior. See *DE- +FINE_STOCHASTIC_VARIATION for additional information. +The MIDFAIL option is available only for shell elements. When included on the +keyword line, this option causes failure to be checked only at the mid-plane of the +element. If an element has an even number of layers, failure is checked in the two +layers closest to the mid-plane. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +6 +7 +8 +SIGY +ETAN +FAIL +TDEL +F +F +F +Default +none +none +none +none +none +0.0 +1021 +F +Card 2 +Variable +Type +Default +1 +C +F +0 + Card 3 +1 +2 +P +F +0 +2 +3 +4 +LCSS +LCSR +F +0 +3 +F +0 +4 +5 +VP +F +0 +5 +6 +7 +8 +6 +7 +8 +Variable +EPS1 +EPS2 +EPS3 +EPS4 +EPS5 +EPS6 +EPS7 +EPS8 +Type +Default +F +0 + Card 4 +1 +F +0 +2 +F +0 +3 +F +0 +4 +F +0 +5 +F +0 +6 +F +0 +7 +F +0 +8 +Variable +ES1 +ES2 +ES3 +ES4 +ES5 +ES6 +ES7 +ES8 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +SIGY +Yield stress. +Figure M24-1. Rate effects may be accounted for by defining a table of curves. If a +table ID is specified a curve ID is given for each strain rate, see *DEFINE_TABLE. +Intermediate values are found by interpolating between curves. Effective plastic +strain versus yield stress is expected. If the strain rate values fall out of range, +extrapolation is not used; rather, either the first or last curve determines the yield +stress depending on whether the rate is low or high, respectively. + VARIABLE +DESCRIPTION +ETAN +Tangent modulus, ignored if (LCSS.GT.0) is defined. +FAIL +Failure flag. +LT.0.0: User defined failure subroutine, matusr_24 in dyn21.F, +is called to determine failure +EQ.0.0: Failure is not considered. This option is recommended +if failure is not of interest since many calculations will +be saved. +GT.0.0: Effective plastic strain to failure. When the plastic +strain reaches this value, the element is deleted from +the calculation. +TDEL +Minimum time step size for automatic element deletion. +C +Strain rate parameter, 𝐶, see formula below. +VARIABLE +DESCRIPTION +P +Strain rate parameter, 𝑃, see formula below. +LCSS +Load curve ID or Table ID. +Load Curve. When LCSS is a Load curve ID, it is taken as +defining effective stress versus effective plastic strain. If defined +EPS1 - EPS8 and ES1 - ES8 are ignored. +Tabular Data. The table ID defines for each strain rate value a +load curve ID giving the stress versus effective plastic strain for +that rate, See Figure M24-1. When the strain rate falls below the +minimum value, the stress versus effective plastic strain curve for +the lowest value of strain rate is used. Likewise, when the strain +rate exceeds the maximum value the stress versus effective plastic +strain curve for the highest value of strain rate is used. The strain +rate parameters: C and P, the curve ID, LCSR, EPS1 - EPS8, and + Linear +ES1 - ES8 are ignored if a Table ID is defined. +interpolation between the discrete strain rates is used by default; +logarithmic +the +LOG_INTERPOLATION option is invoked. +interpolation +when +used +is +interpolation between discrete strain rates +Logarithmically Defined Tables. An alternative way to invoke +logarithmic +is +described as follows. If the first value in the table is negative, LS- +DYNA assumes that all the table values represent the natural +logarithm of a strain rate. Since the tables are internally +discretized to equally space the table values, it makes good sense +from an accuracy standpoint that the table values represent the +natural log of strain rate when the lowest strain rate and highest +strain rate differ by several orders of magnitude. There is some +additional computational cost associated invoking logarithmic +interpolation. +Load curve ID defining strain rate scaling effect on yield stress. If +LCSR is negative, the load curve is evaluated using a binary +search for the correct interval for the strain rate. The binary +search is slower than the default incremental search, but in cases +where large changes in the strain rate may occur over a single +time step, it is more robust. This option is not necessary for the +viscoplastic formulation. +LCSR +*MAT_PIECEWISE_LINEAR_PLASTICITY +DESCRIPTION +VP +Formulation for rate effects: +EQ.-1.0: Cowper-Symonds with deviatoric strain rate rather +than total, +EQ.0.0: Scale yield stress (default), +EQ.1.0: Viscoplastic formulation. +EPS1 - EPS8 +Effective plastic strain values (optional; supersedes SIGY, ETAN). +At least 2 points should be defined. The first point must be zero +corresponding to the initial yield stress. WARNING: If the first +point is nonzero the yield stress is extrapolated to determine the +initial yield. If this option is used SIGY and ETAN are ignored +and may be input as zero. +ES1 - ES8 +Corresponding yield stress values to EPS1 - EPS8. +Remarks: +The stress strain behavior may be treated by a bilinear stress strain curve by defining +the tangent modulus, ETAN. Alternately, a curve of effective stress vs. effective plastic +strain similar to that shown in Figure M10-1 may be defined by (EPS1, ES1) - +(EPS8, ES8); however, a curve ID (LCSS) may be referenced instead if eight points are +insufficient. The cost is roughly the same for either approach. Note that in the special +case of uniaxial stress, true stress vs. true plastic strain is equivalent to effective stress +vs. effective plastic strain. The most general approach is to use the table definition +(LCSS) discussed below. +Three options to account for strain rate effects are possible. +1. Strain rate may be accounted for using the Cowper and Symonds model which +scales the yield stress with the factor +1 + ( +𝑝⁄ +) +𝜀̇ +where 𝜀̇ is the strain rate. 𝜀̇ = √𝜀̇𝑖𝑗𝜀̇𝑖𝑗. If VP = -1. The deviatoric strain rates are +used instead. +If the viscoplastic option is active, VP = 1.0, and if SIGY is > 0 then the dynamic +𝑝 ), which is +yield stress is computed from the sum of the static stress, 𝜎𝑦 +typically given by a load curve ID, and the initial yield stress, SIGY, multiplied +by the Cowper-Symonds rate term as follows: +𝑠(𝜀eff +𝜎𝑦(𝜀eff +𝑝 , 𝜀̇eff +𝑝 ) = 𝜎𝑦 +𝑠(𝜀eff +𝑝 ) + SIGY × +𝑝⁄ +𝜀̇eff +⎟⎞ +𝐶 ⎠ +⎜⎛ +⎝ +where the plastic strain rate is used. With this latter approach similar results +can be obtained between this model and material model: *MAT_ANISOTROP- +IC_VISCOPLASTIC. If SIGY = 0, the following equation is used instead where +𝑝 ), must be defined by a load curve: +the static stress, 𝜎𝑦 +𝑠(𝜀eff +𝜎𝑦(𝜀eff +𝑝 , 𝜀̇eff +𝑝 ) = 𝜎𝑦 +𝑝 ) +𝑠(𝜀eff +𝜀̇eff +⎟⎞ +𝐶 ⎠ +⎜⎛ +⎝ +⎡ +1 + +⎢⎢ +⎣ +𝑝⁄ +⎤ +⎥⎥ +⎦ +This latter equation is always used if the viscoplastic option is off. +2. For complete generality a load curve (LCSR) to scale the yield stress may be +input instead. In this curve the scale factor versus strain rate is defined. +3. +If different stress versus strain curves can be provided for various strain rates, +the option using the reference to a table (LCSS) can be used. Then the table +input in *DEFINE_TABLE has to be used, see Figure M24-1. +A fully viscoplastic formulation is optional (variable VP) which incorporates the +different options above within the yield surface. An additional cost is incurred over the +simple scaling but the improvement is results can be dramatic. +For implicit calculations on this material involving severe nonlinear hardening the +radial return method may result in inaccurate stress-strain response. By setting +IACC = 1 on *CONTROL_ACCURACY activates a fully iterative plasticity algorithm, +which will remedy this. This is not to be confused with the MITER flag on *CON- +TROL_SHELL, which governs the treatment of the plane stress assumption for shell +elements. If failure is applied with this option, incident failure will initiate damage, and +the stress will continuously degrade to zero before erosion for a deformation of 1% +plastic strain. So for instance, if the failure strain is FAIL = 0.05, then the element is +eroded when 𝜀̅𝑝 = 0.06 and the material goes from intact to completely damaged +between 𝜀̅𝑝 = 0.05 and 𝜀̅𝑝 = 0.06. The reason is to enhance implicit performance by +maintaining continuity in the internal forces. +For a nonzero failure strain, *DEFINE_MATERIAL_HISTORIES can be used to output +the failure indicator. +*DEFINE_MATERIAL_HISTORIES Properties +Label +Attributes +Description +Instability +- +- +- +- +Failure indicator 𝜀eff +𝑝 /𝜀fail +𝑝 , see FAIL +*DEFINE_MATERIAL_HISTORIES Properties +Label +Attributes +Description +Plastic Strain Rate +- +- +- +- +𝑝 +Effective plastic strain rate 𝜀̇eff +*MAT_025 +This is Material Type 25. This is an inviscid two invariant geologic cap model. This +material model can be used for geomechanical problems or for materials as concrete, see +references cited below. + Card 1 +1 +Variable +MID +2 +RO +3 +BULK +Type +A8 + Card 2 +Variable +Type +1 +R +F + Card 3 +1 +F +2 +D +F +2 +F +3 +W +F +3 +4 +G +F +4 +X0 +F +4 +Variable +PLOT +FTYPE +VEC +TOFF +Type +F +F +F +F +5 +6 +7 +8 +ALPHA +THETA +GAMMA +BETA +F +5 +C +F +5 +F +6 +N +F +6 +F +7 +F +8 +7 +8 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +BULK +Initial bulk modulus, K. +G +Initial Shear modulus. +ALPHA +THETA +Failure envelope parameter, α. +Failure envelope linear coefficient, θ. +GAMMA +Failure envelope exponential coefficient, γ. +*MAT_GEOLOGIC_CAP_MODEL +DESCRIPTION +BETA +Failure envelope exponent, β. +R +D +W +X0 +C +N +Cap, surface axis ratio. +Hardening law exponent. +Hardening law coefficient. +Hardening law exponent, X0. +Kinematic hardening coefficient, 𝑐̅. +Kinematic hardening parameter. +PLOT +Save the following variable for plotting in LS-PrePost, to be +labeled there as “effective plastic strain:” +EQ.1: hardening parameter, κ +EQ.2: cap -J1 axis intercept, X(κ) +𝑝 +EQ.3: volumetric plastic strain 𝜀𝑣 +EQ.4: first stress invariant, 𝐽1 +EQ.5: second stress invariant, √𝐽2 +EQ.6: not used +EQ.7: not used +EQ.8: response mode number +EQ.9: number of iterations +FTYPE +Formulation flag: +EQ.1: soils (Cap surface may contract) +EQ.2: concrete and rock (Cap doesn’t contract) +VEC +Vectorization flag: +EQ.0: vectorized (fixed number of iterations) +EQ.1: fully iterative +If the vectorized solution is chosen, the stresses might be slightly +off the yield surface; however, on vector computers a much more +efficient solution is achieved. +TOFF +Tension Cut Off, TOFF < 0 (positive in compression). +J2D +J2D = Fe +f1 +J2D = Fc +f2 +J1 +X(κ) +f3 +Figure M25-1. The yield surface of the two-invariant cap model in +pressure√𝐽2𝐷 − 𝐽1 space. Surface f1 is the failure envelope, f2 is the cap surface, +and f3 is the tension cutoff. +Remarks: +The implementation of an extended two invariant cap model, suggested by Stojko +[1990], is based on the formulations of Simo, et al. [1988, 1990] and Sandler and Rubin +[1979]. In this model, the two invariant cap theory is extended to include nonlinear +kinematic hardening as suggested by Isenberg, Vaughan, and Sandler [1978]. A brief +discussion of the extended cap model and its parameters is given below. +The cap model is formulated in terms of the invariants of the stress tensor. The square +root of the second invariant of the deviatoric stress tensor, √𝐽2𝐷 is found from the +deviatoric stresses s as +√𝐽2𝐷 ≡ √ +𝑆𝑖𝑗𝑆𝑖𝑗 +and is the objective scalar measure of the distortional or shearing stress. The first +invariant of the stress, J1, is the trace of the stress tensor. +The cap model consists of three surfaces in √𝐽2𝐷 − 𝐽1 space, as shown in Figure M25-1 +First, there is a failure envelope surface, denoted f1 in the figure. The functional form of +f1 is +where Fe is given by +𝑓1 = √𝐽2𝐷 − min[𝐹𝑒(𝐽1), 𝑇mises], +𝐹𝑒(𝐽1) ≡ 𝛼 − 𝛾exp(−𝛽𝐽1) + 𝜃𝐽1 +and 𝑇𝑚𝑖𝑠𝑒𝑠 ≡ |𝑋(𝜅𝑛) − 𝐿(𝜅𝑛)|. This failure envelop surface is fixed in √𝐽2𝐷 − 𝐽1 space, +and therefore does not harden unless kinematic hardening is present. Next, there is a +cap surface, denoted f2 in the figure, with f2 given by +𝑓2 = √𝐽2𝐷 − 𝐹𝑐(𝐽1, 𝐾) +where Fc is defined by +𝐹𝑐(𝐽1, 𝜅) ≡ +√[𝑋(𝜅) − 𝐿(𝜅)]2 − [𝐽1 − 𝐿(𝜅)]2, +𝑋(𝜅) is the intersection of the cap surface with the J1 axis +and 𝐿(𝜅) is defined by +𝑋(𝜅) = 𝜅 + 𝑅𝐹𝑒(𝜅), +𝐿(𝜅) ≡ {𝜅 if 𝜅 > 0 +0 if 𝜅 ≤ 0 +The hardening parameter κ is related to the plastic volume change 𝜀𝑣 +hardening law +𝑝 through the +𝑝 = 𝑊{1 − exp[−𝐷(𝑋(𝜅) − 𝑋0)]} +𝜀𝑣 +Geometrically, κ is seen in the figure as the J1 coordinate of the intersection of the cap +surface and the failure surface. Finally, there is the tension cutoff surface, denoted f3 in +the figure. The function f3 is given by +f3 ≡ T − J1 +where T is the input material parameter which specifies the maximum hydrostatic +tension sustainable by the material. The elastic domain in √𝐽2𝐷 − 𝐽1 space is then +bounded by the failure envelope surface above, the tension cutoff surface on the left, +and the cap surface on the right. +An additive decomposition of the strain into elastic and plastic parts is assumed: +𝜺 = 𝜺𝑒 + 𝜺𝑝, +where εe is the elastic strain and εp is the plastic strain. Stress is found from the elastic +strain using Hooke’s law, +where σ is the stress and C is the elastic constitutive tensor. +𝝈 = 𝑪(𝜺 − 𝜺𝒑), +The yield condition may be written +𝑓1(𝑠) ≤ 0 +𝑓2(𝑠, 𝜅) ≤ 0 +𝑓3(𝑠) ≤ 0 +and the plastic consistency condition requires that +𝜆̇𝑘𝑓𝑘 = 0 +𝑘 = 1,2,3 +𝜆̇𝑘 ≥ 0 +where 𝜆𝑘 is the plastic consistency parameter for surface k. If 𝑓𝑘 < 0 then, 𝜆̇𝑘 = 0 and the +response is elastic. If 𝑓𝑘 > 0 then surface k is active and 𝜆̇𝑘 is found from the +requirement that 𝑓 ̇ +𝑘 = 0. +Associated plastic flow is assumed, so using Koiter’s flow rule the plastic strain rate is +given as the sum of contribution from all of the active surfaces, +𝜀̇𝑝 = ∑ 𝜆̇𝑘 +𝑘=1 +∂𝑓𝑘 +∂𝑠 +. +One of the major advantages of the cap model over other classical pressure-dependent +plasticity models is the ability to control the amount of dilatancy produced under shear +loading. Dilatancy is produced under shear loading as a result of the yield surface +having a positive slope in √𝐽2𝐷 − 𝐽 space, so the assumption of plastic flow in the +direction normal to the yield surface produces a plastic strain rate vector that has a +component in the volumetric (hydrostatic) direction . In models such +as the Drucker-Prager and Mohr-Coulomb, this dilatancy continues as long as shear +loads are applied, and in many cases produces far more dilatancy than is experimental- +ly observed in material tests. In the cap model, when the failure surface is active, +dilatancy is produced just as with the Drucker-Prager and Mohr-Coulumb models. +However, the hardening law permits the cap surface to contract until the cap intersects +the failure envelope at the stress point, and the cap remains at that point. The local +normal to the yield surface is now vertical, and therefore the normality rule assures that +no further plastic volumetric strain (dilatancy) is created. Adjustment of the parameters +that control the rate of cap contractions permits experimentally observed amounts of +dilatancy to be incorporated into the cap model, thus producing a constitutive law +which better represents the physics to be modeled. +Another advantage of the cap model over other models such as the Drucker-Prager and +Mohr-Coulomb is the ability to model plastic compaction. In these models all purely +volumetric response is elastic. In the cap model, volumetric response is elastic until the +stress point hits the cap surface. Therefore, plastic volumetric strain (compaction) is +generated at a rate controlled by the hardening law. Thus, in addition to controlling the +amount of dilatancy, the introduction of the cap surface adds another experimentally +observed response characteristic of geological material into the model. +The inclusion of kinematic hardening results in hysteretic energy dissipation under +cyclic loading conditions. Following the approach of Isenberg, et al. [1978] a nonlinear +kinematic hardening law is used for the failure envelope surface when nonzero values +of and N are specified. In this case, the failure envelope surface is replaced by a family +of yield surfaces bounded by an initial yield surface and a limiting failure envelope +surface. Thus, the shape of the yield surfaces described above remains unchanged, but +they may translate in a plane orthogonal to the J axis, +Translation of the yield surfaces is permitted through the introduction of a “back stress” +tensor, α The formulation including kinematic hardening is obtained by replacing the +stress σ with the translated stress tensor 𝜂 ≡ 𝜎 − 𝛼 in all of the above equation. The +history tensor α is assumed deviatoric, and therefore has only 5 unique components. +The evolution of the back stress tensor is governed by the nonlinear hardening law +𝛼 = 𝑐 ̅𝐹̅(𝜎, 𝛼)𝑒 ̇𝑝 +where 𝑐 ̅ is a constant, 𝐹̅ is a scalar function of σ and α and 𝑒 ̇𝑝 is the rate of deviatoric +plastic strain. The constant may be estimated from the slope of the shear stress - plastic +shear strain curve at low levels of shear stress. +The function 𝐹̅ is defined as +𝐹̅ ≡ max [0,1 − +(𝜎 − 𝛼)𝛼 +2𝑁𝐹𝑒(𝐽1) +] +where N is a constant defining the size of the yield surface. The value of N may be +interpreted as the radial distant between the outside of the initial yield surface and the +inside of the limit surface. In order for the limit surface of the kinematic hardening cap +model to correspond with the failure envelope surface of the standard cap model, the +scalar parameter α must be replaced α - N in the definition Fe. +The cap model contains a number of parameters which must be chosen to represent a +particular material, and are generally based on experimental data. The parameters α, β, +θ, and γ are usually evaluated by fitting a curve through failure data taken from a set of +triaxial compression tests. The parameters W, D, and X0 define the cap hardening law. +The value W represents the void fraction of the uncompressed sample and D governs +the slope of the initial loading curve in hydrostatic compression. The value of R is the +ration of major to minor axes of the quarter ellipse defining the cap surface. Additional +details and guidelines for fitting the cap model to experimental data are found in Chen +and Baladi [1985]. +*MAT_026 +This is Material Type 26. The major use of this material model is for honeycomb and +foam materials with real anisotropic behavior. A nonlinear elastoplastic material +behavior can be defined separately for all normal and shear stresses. These are +considered to be fully uncoupled. See notes below. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +SIGY +F +6 +VF +F +7 +8 +MU +BULK +F +F +Default +none +none +none +none +none +none +.05 +0.0 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCA +LCB +LCC +LCS +LCAB +LCBC +LCCA +LCSR +Type +F +F +F +F +F +F +F +F +Default +none +LCA +LCA +LCA +LCS +LCS +LCS +optional + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EAAU +EBBU +ECCU +GABU +GBCU +GCAU +AOPT +MACF +Type +F +F +F +F +F +F + Card 4 +Variable +1 +XP +Type +F +2 +YP +F +3 +ZP +F +4 +A1 +F +5 +A2 +F +6 +A3 +F +I +8 +Variable +1 +D1 +Type +F +*MAT_HONEYCOMB +2 +D2 +F +3 +D3 +F +4 +5 +TSEF +SSEF +F +F +6 +V1 +F +7 +V2 +F +8 +V3 +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus for compacted honeycomb material. +Poisson’s ratio for compacted honeycomb material. +SIGY +Yield stress for fully compacted honeycomb. +VF +MU +Relative volume at which the honeycomb is fully compacted. +μ, material viscosity coefficient. (default=.05) Recommended. +BULK +Bulk viscosity flag: +LCA +LCB +LCC +LCS +EQ.0.0: bulk viscosity is not used. This is recommended. +EQ.1.0: bulk viscosity is active and μ = 0. This will give results +identical to previous versions of LS-DYNA. +Load curve ID, see *DEFINE_CURVE, for sigma-aa versus either +relative volume or volumetric strain. See notes below. +Load curve ID, see *DEFINE_CURVE, for sigma-bb versus either +relative volume or volumetric strain. Default LCB = LCA. See +notes below. +Load curve ID, see *DEFINE_CURVE, for sigma-cc versus either +relative volume or volumetric strain. Default LCC = LCA. See +notes below. +Load curve ID, see *DEFINE_CURVE, for shear stress versus +either relative volume or volumetric strain. Default LCS = LCA. +Each component of shear stress may have its own load curve. See +notes below. +VARIABLE +LCAB +LCBC +LCCA +LCSR +EAAU +EBBU +ECCU +GABU +GBCU +GCAU +AOPT +DESCRIPTION +Load curve ID, see *DEFINE_CURVE, for sigma-ab versus either +relative volume or volumetric strain. Default LCAB = LCS. See +notes below. +Load curve ID, see *DEFINE_CURVE, for sigma-bc versus either +relative volume or volumetric strain. Default LCBC = LCS. See +notes below. +Load curve ID, see *DEFINE_CURVE, or sigma-ca versus either +relative volume or volumetric strain. Default LCCA = LCS. See +notes below. +Load curve ID, see *DEFINE_CURVE, for strain-rate effects +defining the scale factor versus strain rate. This is optional. The +curves defined above are scaled using this curve. +Elastic modulus Eaau in uncompressed configuration. +Elastic modulus Ebbu in uncompressed configuration. +Elastic modulus Eccu in uncompressed configuration. +Shear modulus Gabu in uncompressed configuration. +Shear modulus Gbcu in uncompressed configuration. +Shear modulus Gcau in uncompressed configuration. +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the a-direction. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +*MAT_HONEYCOMB +DESCRIPTION +element normal. The plane of a solid element is the +midsurface between the inner surface and outer surface +defined by the first four nodes and the last four nodes +of the connectivity of the element, respectively. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector v, and +an originating point, p, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later.. +MACF +Material axes change flag: +EQ.1: No change, default, +EQ.2: switch material axes a and b, +EQ.3: switch material axes a and c, +EQ.4: switch material axes b and c. +XP YP ZP +Coordinates of point p for AOPT = 1 and 4. +A1 A2 A3 +Components of vector a for AOPT = 2. +D1 D2 D3 +Components of vector d for AOPT = 2. +V1 V2 V3 +Define components of vector v for AOPT = 3 and 4. +Tensile strain at element failure (element will erode). +Shear strain at element failure (element will erode). +TSEF +SSEF +Remarks: +For efficiency it is strongly recommended that the load curve ID’s: LCA, LCB, LCC, +LCS, LCAB, LCBC, and LCCA, contain exactly the same number of points with +corresponding strain values on the abscissa. If this recommendation is followed the +cost of the table lookup is insignificant. Conversely, the cost increases significantly if +the abscissa strain values are not consistent between load curves. +The behavior before compaction is orthotropic where the components of the stress +tensor are uncoupled, i.e., an a component of strain will generate resistance in the local +a-direction with no coupling to the local b and c directions. The elastic moduli vary, +from their initial values to the fully compacted values at Vf, linearly with the relative +volume V: +𝐸𝑎𝑎 = 𝐸𝑎𝑎𝑢 + 𝛽(𝐸 − 𝐸𝑎𝑎𝑢) +𝐸𝑏𝑏 = 𝐸𝑏𝑏𝑢 + 𝛽(𝐸 − 𝐸𝑏𝑏𝑢) +𝐸𝑐𝑐 = 𝐸𝑐𝑐𝑢 + 𝛽(𝐸 − 𝐸𝑐𝑐𝑢) +𝐺𝑎𝑏 = 𝐸𝑎𝑏𝑢 + 𝛽(𝐺 − 𝐺𝑎𝑏𝑢) +𝐺𝑏𝑐 = 𝐸𝑏𝑐𝑢 + 𝛽(𝐺 − 𝐺𝑏𝑐𝑢) +𝐺𝑐𝑎 = 𝐸𝑐𝑎𝑢 + 𝛽(𝐺 − 𝐺𝑐𝑎𝑢) +𝛽 = max [min ( +1 − 𝑉 +1 − 𝑉𝑓 +, 1) , 0] +where +and G is the elastic shear modulus for the fully compacted honeycomb material +𝐺 = +2(1 + 𝑣) +. +The relative volume, V, is defined as the ratio of the current volume to the initial +volume. Typically, V = 1 at the beginning of a calculation. The viscosity coefficient µ +(MU) should be set to a small number (usually .02 - .10 is okay). Alternatively, the two +bulk viscosity coefficients on the control cards should be set to very small numbers to +prevent the development of spurious pressures that may lead to undesirable and +confusing results. The latter is not recommended since spurious numerical noise may +develop. +Curve extends into negative volumetric +strain quadrant since LS-DYNA will +extrapolate using the two end points. It +is important that the extropolation +does not extend into the negative + σ +ij +unloading and +reloading path +Strain: -ε +ij +Unloading is based on the interpolated Young’s +moduli which must provide an unloading tangent +that exceeds the loading tangent. +Figure M26-1. Stress quantity versus volumetric strain. Note that the “yield +stress” at a volumetric strain of zero is non-zero. In the load curve definition, +see *DEFINE_CURVE, the “time” value is the volumetric strain and the +“function” value is the yield stress. +The load curves define the magnitude of the average stress as the material changes +density (relative volume), see Figure M26-1. Each curve related to this model must +have the same number of points and the same abscissa values. There are two ways to +define these curves, a) as a function of relative volume (V) or b) as a function of +volumetric strain defined as: +𝜀𝑉 = 1 − 𝑉 +In the former, the first value in the curve should correspond to a value of relative +volume slightly less than the fully compacted value. In the latter, the first value in the +curve should be less than or equal to zero, corresponding to tension, and increase to full +compaction. Care should be taken when defining the curves so that extrapolated +values do not lead to negative yield stresses. +At the beginning of the stress update each element’s stresses and strain rates are +transformed into the local element coordinate system. For the uncompacted material, +the trial stress components are updated using the elastic interpolated moduli according +to: +𝑛+1trial +𝜎𝑎𝑎 +𝑛+1trial +𝜎𝑏𝑏 +𝑛+1trial +𝜎𝑐𝑐 +𝑛+1trial +𝜎𝑎𝑏 += 𝜎𝑎𝑎 += 𝜎𝑏𝑏 += 𝜎𝑐𝑐 += 𝜎𝑎𝑏 +𝑛 + 𝐸𝑎𝑎Δ𝜀𝑎𝑎 +𝑛 + 𝐸𝑏𝑏Δ𝜀𝑏𝑏 +𝑛 + 𝐸𝑐𝑐Δ𝜀𝑐𝑐 +𝑛 + 2𝐺𝑎𝑏Δ𝜀𝑎𝑏 +𝑛+1trial +𝜎𝑏𝑐 += 𝜎𝑏𝑐 +𝑛 + 2𝐺𝑏𝑐Δ𝜀𝑏𝑐 +𝑛+1trial +𝜎𝑐𝑎 += 𝜎𝑐𝑎 +𝑛 + 2𝐺𝑐𝑎Δ𝜀𝑐𝑎 +Each component of the updated stresses is then independently checked to ensure that +they do not exceed the permissible values determined from the load curves; e.g., if +then +𝑛+1trial +∣𝜎𝑖𝑗 +∣ > 𝜆𝜎𝑖𝑗(𝑉) +𝑛+1 = 𝜎𝑖𝑗(𝑉) +𝜎𝑖𝑗 +𝑛+1trial +𝜆𝜎𝑖𝑗 +∣𝜆𝜎𝑖𝑗 +𝑛+1trial∣ +On Card 2 σij (V) is defined by LCA for the aa stress component, LCB for the bb +component, LCC for the cc component, and LCS for the ab, bc, ca shear stress +components. The parameter λ is either unity or a value taken from the load curve +number, LCSR, that defines λ as a function of strain-rate. Strain-rate is defined here as +the Euclidean norm of the deviatoric strain-rate tensor. +For fully compacted material it is assumed that the material behavior is elastic-perfectly +plastic and the stress components updated according to: +where the deviatoric strain increment is defined as +trial = 𝑠𝑖𝑗 +𝑠𝑖𝑗 +𝑑𝑒𝑣 +𝑛 + 2𝐺Δ𝜀𝑖𝑗 +𝑛+1 +2⁄ +Δ𝜀𝑖𝑗 +dev = Δ𝜀𝑖𝑗 − +Δ𝜀𝑘𝑘𝛿𝑖𝑗 +Now a check is made to see if the yield stress for the fully compacted material is +exceeded by comparing +trial = ( +𝑠eff +2⁄ +trial) +trial𝑠𝑖𝑗 +𝑠𝑖𝑗 +the effective trial stress to the defined yield stress, SIGY. If the effective trial stress +exceeds the yield stress the stress components are simply scaled back to the yield +surface +Now the pressure is updated using the elastic bulk modulus, K +𝑛+1 = +𝑠𝑖𝑗 +𝜎𝑦 +trial +𝑠eff +trial. +𝑠𝑖𝑗 +where +𝑛+1 +𝑝𝑛+1 = 𝑝𝑛 − 𝐾Δ𝜀𝑘𝑘 +2⁄ +𝐾 = +3(1 − 2𝑣) +to obtain the final value for the Cauchy stress +𝑛+1 = 𝑠𝑖𝑗 +𝜎𝑖𝑗 +𝑛+1 − 𝑝𝑛+1𝛿𝑖𝑗 +After completing the stress update transform the stresses back to the global +configuration. +For *CONSTRAINED_TIED_NODES_WITH_FAILURE, the failure is based on the +volume strain instead to the plastic strain. +*MAT_MOONEY-RIVLIN_RUBBER +This is Material Type 27. A two-parametric material model for rubber can be defined. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +Variable +SGL +SW +Type +F +F +3 +PR +F +3 +ST +F +4 +A +F +4 +LCID +F +5 +B +F +5 +6 +REF +F +6 +7 +8 +7 +8 + VARIABLE +DESCRIPTION +MID +RO +PR +A +B +REF +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Poisson’s ratio (value between 0.49 and 0.5 is recommended, +smaller values may not work). +Constant, see literature and equations defined below. +Constant, see literature and equations defined below. +Use reference geometry to initialize the stress tensor. The +reference geometry is defined by the keyword:*INITIAL_FOAM_- +REFERENCE_GEOMETRY . +EQ.0.0: off, +EQ.1.0: on. +If the values on Card 2 are nonzero, then a least squares fit is computed from the +uniaxial data provided by the curve LCID superceding the A and B values on Card 1. +If the A and B fields are left blank on Card 1 then the variables on Card 2 must be +nonzero. +SGL +Specimen gauge length 𝑙0, see Figure M27-1. +*MAT_MOONEY-RIVLIN_RUBBER +DESCRIPTION +Specimen width, see Figure M27-1. +Specimen thickness, see Figure M27-1. +Curve ID, see *DEFINE_CURVE, giving the force versus actual +change 𝐿 in the gauge length. See also Figure M27-2 for an +alternative definition. +*MAT_027 + VARIABLE +SW +ST +LCID +Remarks: +The strain energy density function is defined as: +𝑊 = 𝐴(𝐼 − 3) + 𝐵(𝐼𝐼 − 3) + 𝐶(𝐼𝐼𝐼−2 − 1) + 𝐷(𝐼𝐼𝐼 − 1)2 +where +𝐶 = 0.5𝐴 + 𝐵 +𝐷 = +𝐴(5𝜐 − 2) + 𝐵(11𝜐 − 5) +2(1 − 2𝜐) +𝜈 = Poisson’s ratio +2(𝐴 + 𝐵) = shear modulus of linear elasticity +𝐼, 𝐼𝐼, 𝐼𝐼𝐼 = invariants of right Cauchy-Green Tensor C. +The load curve definition that provides the uniaxial data should give the change in +gauge length, Δ𝐿, versus the corresponding force. In compression both the force and +the change in gauge length must be specified as negative values. In tension the force +and change in gauge length should be input as positive values. The principal stretch +ratio in the uniaxial direction, 𝜆1, is then given by +𝐿0 + Δ𝐿 +𝐿0 +𝜆1 = +with 𝐿0 being the initial length and 𝐿 being the actual length. +Alternatively, the stress versus strain curve can also be input by setting the gauge +length, thickness, and width to unity (1.0) and defining the engineering strain in place +of the change in gauge length and the nominal (engineering) stress in place of the force, +see Figure M27-1. +The least square fit to the experimental data is performed during the initialization phase +and is a comparison between the fit and the actual input is provided in the d3hsp file. +It is a good idea to visually check to make sure it is acceptable. The coefficients 𝐴 and 𝐵 +are also printed in the output file. It is also advised to use the material driver for checking out the material model. +gauge +length +Force +AA +Δ gauge length +Section AA +thickness +width +Figure M27-1. Uniaxial specimen for experimental data +applied force +initial area += +A0 +change in gauge length +gauge length += +∆L +Figure M27-2 The stress versus strain curve can used instead of the force +versus the change in the gauge length by setting the gauge length, thickness, +and width to unity (1.0) and defining the engineering strain in place of the +change in gauge length and the nominal (engineering) stress in place of the +force. *MAT_077_O is a better alternative for fitting data resembling the curve +above. *MAT_027 will provide a poor fit to a curve that exhibits an strong +upturn in slope as strains become large. +*MAT_RESULTANT_PLASTICITY +This is Material Type 28. A resultant formulation for beam and shell elements +including elasto-plastic behavior can be defined. This model is available for the +Belytschko-Schwer beam, the Co triangular shell, the Belytschko-Tsay shell, and the +fully integrated type 16 shell. For beams, the treatment is elastic-perfectly plastic, but +for shell elements isotropic hardening is approximately modeled. For a detailed +description we refer to the LS-DYNA Theory Manual. Since the stresses are not +computed in the resultant formulation, the stresses output to the binary databases for +the resultant elements are zero. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +6 +7 +8 +SIGY +ETAN +F +F +Default +none +none +none +none +none +0.0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +SIGY +ETAN +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus +Poisson’s ratio +Yield stress +Plastic hardening modulus (for shells only) +*MAT_029 +This is Material Type 29. With this material model, for the Belytschko-Schwer beam +only, plastic hinge forming at the ends of a beam can be modeled using curve +definitions. Optionally, collapse can also be modeled. See also *MAT_139. +Description: FORCE LIMITED Resultant Formulation + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +DF +F +6 +7 +8 +AOPT +YTFLAG +ASOFT +F +F +F +Default +none +none +none +none +0.0 +0.0 +0.0 +0.0 + Card 2 +1 +Variable +M1 +Type +F +Default +none + Card 3 +1 +2 +M2 +F +0 +2 +3 +M3 +F +0 +3 +4 +M4 +F +0 +4 +5 +M5 +F +0 +5 +6 +M6 +F +0 +6 +7 +M7 +F +0 +7 +8 +M8 +F +0 +8 +Variable +LC1 +LC2 +LC3 +LC4 +LC5 +LC6 +LC7 +LC8 +Type +F +Default +none +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LPS1 +SFS1 +LPS2 +SFS2 +YMS1 +YMS2 +Type +Default +F +0 +F +F +F +F +F +1.0 +LPS1 +1.0 +1.0E+20 YMS1 + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LPT1 +SFT1 +LPT2 +SFT2 +YMT1 +YMT2 +Type +Default +F +0 +F +F +F +F +F +1.0 +LPT1 +1.0 +1.0E+20 YMT1 + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LPR +SFR +YMR +Type +Default +F +0 +F +F +1.0 +1.0E+20 + VARIABLE +DESCRIPTION +MID +RO +E +PR +DF +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus +Poisson’s ratio +Damping factor, see definition in notes below. A proper control +for the timestep has to be maintained by the user! +VARIABLE +DESCRIPTION +AOPT +Axial load curve option: +EQ.0.0: axial load curves are force versus strain, +EQ.1.0: axial load curves are force versus change in length. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +YTFLAG +Flag to allow beam to yield in tension: +EQ.0.0: beam does not yield in tension, +EQ.1.0: beam can yield in tension. +ASOFT +M1, M2, +…, M8 +LC1, LC2, +…, LC8 +LPS1 +SFS1 +LPS2 +SFS2 +YMS1 +Axial elastic softening factor applied once hinge has formed. +When a hinge has formed the stiffness is reduced by this factor. If +zero, this factor is ignored. +Applied end moment for force versus (strain/change in length) +curve. At least one must be defined. A maximum of 8 moments +can be defined. The values should be in ascending order. +Load curve ID defining axial force +(collapse load) versus strain/change in length for the +corresponding applied end moment. Define the same number as +end moments. Each curve must contain the same number of +points. +Load curve ID for plastic moment versus rotation about s-axis at +node 1. If zero, this load curve is ignored. +Scale factor for plastic moment versus rotation curve about s-axis +at node 1. Default = 1.0. +Load curve ID for plastic moment versus rotation about s-axis at +node 2. Default: is same as at node 1. +Scale factor for plastic moment versus rotation curve about s-axis +at node 2. Default: is same as at node 1. +Yield moment about s-axis at node 1 for interaction calculations +(default set to 1.0E+20 to prevent interaction). +*MAT_FORCE_LIMITED +DESCRIPTION +Yield moment about s-axis at node 2 for interaction calculations +(default set to YMS1). +Load curve ID for plastic moment versus rotation about t-axis at +node 1. If zero, this load curve is ignored. +Scale factor for plastic moment versus rotation curve about t-axis +at node 1. Default = 1.0. +Load curve ID for plastic moment versus rotation about t-axis at +node 2. Default: is the same as at node 1. +Scale factor for plastic moment versus rotation curve about t-axis +at node 2. Default: is the same as at node 1. +Yield moment about t-axis at node 1 for interaction calculations +(default set to 1.0E+20 to prevent interactions) +Yield moment about t-axis at node 2 for interaction calculations +(default set to YMT1) +Load curve ID for plastic torsional moment versus rotation. If +zero, this load curve is ignored. +Scale factor for plastic torsional moment versus rotation +(default = 1.0). +Torsional yield moment for interaction calculations (default set to +1.0E+20 to prevent interaction) +YMS2 +LPT1 +SFT1 +LPT2 +SFT2 +YMT1 +YMT2 +LPR +SFR +YMR +Remarks: +This material model is available for the Belytschko resultant beam element only. Plastic +hinges form at the ends of the beam when the moment reaches the plastic moment. The +moment versus rotation relationship is specified by the user in the form of a load curve +and scale factor. The points of the load curve are (plastic rotation in radians, plastic +moment). Both quantities should be positive for all points, with the first point being +(zero, initial plastic moment). Within this constraint any form of characteristic may be +used, including flat or falling curves. Different load curves and scale factors may be +specified at each node and about each of the local s and t axes. +Axial collapse occurs when the compressive axial load reaches the collapse load. +Collapse load versus collapse deflection is specified in the form of a load curve. The +points of the load curve are either (true strain, collapse force) or (change in length, +collapse force). Both quantities should be entered as positive for all points, and will be +interpreted as compressive. The first point should be (zero, initial collapse load). +The collapse load may vary with end moment as well as with deflections. In this case +several load-deflection curves are defined, each corresponding to a different end +moment. Each load curve should have the same number of points and the same +deflection values. The end moment is defined as the average of the absolute moments +at each end of the beam and is always positive. +Stiffness-proportional damping may be added using the damping factor λ. This is +defined as follows: +𝜆 = +2 × 𝜉 +where ξ is the damping factor at the reference frequency ω (in radians per second). For +example if 1% damping at 2Hz is required +𝜆 = +2 × 0.01 +2𝜋 × 2 += 0.001592 +If damping is used, a small timestep may be required. LS-DYNA does not check this so +to avoid instability it may be necessary to control the timestep via a load curve. As a +guide, the timestep required for any given element is multiplied by 0.3L⁄cλ when +damping is present (L = element length, c = sound speed). +Moment Interaction: +Plastic hinges can form due to the combined action of moments about the three axes. +This facility is activated only when yield moments are defined in the material input. A +hinge forms when the following condition is first satisfied. +where, +⎜⎛ 𝑀𝑟 +⎟⎞ +𝑀ryield⎠ +⎝ ++ +⎜⎛ 𝑀𝑠 +⎟⎞ +𝑀syield⎠ +⎝ ++ +⎜⎛ 𝑀𝑡 +⎟⎞ +𝑀tyield⎠ +⎝ +≥ 1 +𝑀𝑟, 𝑀𝑠, 𝑀𝑡, = current moment +𝑀𝑟yield, 𝑀𝑠yield, 𝑀𝑡yield = yield moment +Note that scale factors for hinge behavior defined in the input will also be applied to the +yield moments: for example, 𝑀𝑠yield in the above formula is given by the input yield +moment about the local axis times the input scale factor for the local s axis. For strain- +softening characteristics, the yield moment should generally be set equal to the initial +peak of the moment-rotation load curve. +On forming a hinge, upper limit moments are set. These are given by +M8 +M7 +M6 +M5 +M4 +M3 +M2 +M1M1 +Strain (or change in length, see AOPT) +Figure M29-1. The force magnitude is limited by the applied end moment. +For an intermediate value of the end moment LS-DYNA interpolates between +the curves to determine the allowable force value. +𝑀𝑟upper = max +⎜⎛𝑀𝑟, +⎝ +𝑀𝑟yield +⎟⎞ +2 ⎠ +and similar conditions hold for 𝑀𝑠upper and 𝑀𝑡upper. +Thereafter, the plastic moments will be given by +𝑀𝑟𝑝 = min(𝑀𝑟upper, 𝑀𝑟curve) +where, +𝑀𝑟p = current plastic moment +𝑀𝑟curve = moment from load curve at the current rotation scaled by the scale factor. +𝑀𝑠𝑝and 𝑀𝑡𝑝 satisfy similar conditions. +The effect of this is to provide an upper limit to the moment that can be generated; it +represents the softening effect of local buckling at a hinge site. Thus if a member is bent +about is local s-axis it will then be weaker in torsion and about its local t-axis. For +moment-softening curves, the effect is to trim off the initial peak (although if the curves +subsequently harden, the final hardening will also be trimmed off). +It is not possible to make the plastic moment vary with axial load. +*MAT_SHAPE_MEMORY +This is material type 30. This material model describes the superelastic response +present in shape-memory alloys (SMA), that is the peculiar material ability to undergo +large deformations with a full recovery in loading-unloading cycles . +The material response is always characterized by a hysteresis loop. See the references +by Auricchio, Taylor and Lubliner [1997] and Auricchio and Taylor [1997]. This model +is available for shells, solids, and Hughes-Liu beam elements. +5 +6 +7 +8 + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +Default +none +none +none +none + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SIG_ASS SIG_ASF SIG_SAS SIG_SAF +EPSL +ALPHA +YMRT +Type +F +F +F +F +F +F +F +Default +none +none +none +none +none +0.0 +0.0 +Optional Load Curve Card (starting with R7.1). Load curves for mechanically +induced phase transitions. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCID_AS LCID_SA +Type +I +I +Default +none +none +VARIABLE +DESCRIPTION +MID +RO +E +PR +SIG_ASS +SIG_ASF +SIG_SAS +SIG_SAF +EPSL +ALPHA +YMRT +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Density +Young’s modulus +Poisson’s ratio +Starting value for the forward phase transformation (conversion +of austenite into martensite) in the case of a uniaxial tensile state +of stress. A load curve for SIG_ASS as a function of temperature +is specified by using the negative of the load curve ID number. +Final value for the forward phase transformation (conversion of +austenite into martensite) in the case of a uniaxial tensile state of +stress. SIG_ASF as a function of temperature is specified by using +the negative of the load curve ID number. +Starting value for the reverse phase transformation (conversion of +martensite into austenite) in the case of a uniaxial tensile state of +stress. SIG_SAS as a function of temperature is specified by using +the negative of the load curve ID number. +Final value for the reverse phase transformation (conversion of +martensite into austenite) in the case of a uniaxial tensile state of +stress. SIG_SAF as a function of temperature is specified by using +the negative of the load curve ID number. +Recoverable strain or maximum residual strain. It is a measure of +the maximum deformation obtainable all the martensite in one +direction. +Parameter measuring the difference between material responses +in tension and compression (set alpha = 0 for no difference). +Also, see the following Remark. +Young’s modulus for the martensite if it is different from the +modulus for the austenite. Defaults to the austenite modulus if it +is set to zero. +LCID_AS +Load curve ID or Table ID for the forward phase change +(conversion of austenite into martensite). +1. When LCID_AS is a load curve ID the curve is taken to be +*MAT_SHAPE_MEMORY +DESCRIPTION +effective stress versus martensite fraction (ranging from +0 to 1). +2. When LCID_AS is a table ID the table defines for each +phase transition rate (derivative of martensite fraction) a +load curve ID specifying the stress versus martensite +fraction for that phase transition rate. +The stress versus martensite fraction curve for the lowest +value of the phase transition rate is used, if the phase +transition rate falls below the minimum value. Likewise, +the stress versus martensite fraction curve for the highest +value of phase transition rate is used if phase transition +rate exceeds the maximum value. +3. The values of SIG_ASS and SIG_ASF are overwritten +when this option is used. +LCID_SA +Load curve ID or Table ID for reverse phase change (conversion of +martensite into austenite). +1. When LCID_SA is a load curve ID the curve is taken to be +effective stress versus martensite fraction (ranging from +0 to 1). +2. When LCID_SA is a table ID the table defines for each +phase transition rate (derivative of martensite fraction) a +load curve ID specifying the stress versus martensite +fraction for that phase transition rate. +The stress versus martensite fraction curve for the lowest +value of the phase transition rate is used, if the phase +transition rate falls below the minimum value. Likewise, +the stress versus martensite fraction curve for the highest +value of phase transition rate is used if phase transition +rate exceeds the maximum value. +3. The values of SIG_ASS and SIG_ASF are overwritten +when this option is used. +Remarks: +The material parameter alpha, α, measures the difference between material responses in +tension and compression. In particular, it is possible to relate the parameter α to the +σAX +σAS +σSA +σSA +(cid:3) +(cid:3)L +Figure M30-1. Superelastic Behavior for a Shape Memory Material +initial stress value of the austenite into martensite conversion, indicated respectively as +𝐴𝑆,+ and 𝜎𝑠 +𝜎𝑠 +𝐴𝑆,−, according to the following expression: +𝛼 = +𝐴𝑆,− − 𝜎𝑠 +𝜎𝑠 +𝐴𝑆,− + 𝜎𝑠 +𝜎𝑠 +𝐴𝑆,+ +𝐴𝑆,+ +In the following, the results obtained from a simple test problem is reported. The +material properties are set as: +E +PR +60000 MPa +0.3 +SIG_ASS +520 MPa +SIG_ASF +600 MPa +SIG_SAS +300 MPa +SIG_SAF +200 MPa +1000 +500 +-500 +-1000 +-0.1 +-0.05 +0.05 +True Strain + Figure M30-2. Complete loading-unloading test in tension and compression. +EPSL +0.07 +ALPHA +0.12 +YMRT +50000 MPa +The investigated problem is the complete loading-unloading test in tension and +compression. The uniaxial Cauchy stress versus the logarithmic strain is plotted in +Figure M30-2. +*MAT_FRAZER_NASH_RUBBER_MODEL +This is Material Type 31. This model defines rubber from uniaxial test data. It is a +modified form of the hyperelastic constitutive law first described in Kenchington [1988]. +See also the notes below. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +PR +F +3 +4 +5 +6 +7 +8 +C100 +C200 +C300 +C400 +F +4 +F +5 +F +6 +F +7 +8 +Variable +C110 +C210 +C010 +C020 +EXIT +EMAX +EMIN +REF +Type +F + Card 3 +1 +F +2 +Variable +SGL +SW +Type +F +F +F +3 +ST +F +F +4 +LCID +F +F +5 +F +6 +F +7 +F +8 + VARIABLE +DESCRIPTION +MID +RO +PR +C100 +C200 +C300 +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Poisson’s ratio. Values between .49 and .50 are suggested. +C100 (EQ.1.0 if term is in the least squares fit.) +C200 (EQ.1.0 if term is in the least squares fit.) +C300 (EQ.1.0 if term is in the least squares fit.) +C400 +C110 +C210 +C010 +C020 +EXIT +*MAT_FRAZER_NASH_RUBBER_MODEL +DESCRIPTION +C400 (EQ.1.0 if term is in the least squares fit.) +C110 (EQ.1.0 if term is in the least squares fit.) +C210 (EQ.1.0 if term is in the least squares fit.) +C010 (EQ.1.0 if term is in the least squares fit.) +C020 (EQ.1.0 if term is in the least squares fit.) +Exit option: +EQ.0.0: stop if strain limits are exceeded (recommended), +NE.0.0: continue if strain limits are exceeded. The curve is then +extrapolated. +EMAX +Maximum strain limit, (Green-St, Venant Strain). +EMIN +Minimum strain limit, (Green-St, Venant Strain). +Use reference geometry to initialize the stress tensor. The +reference geometry is defined by the keyword: *INITIAL_- +FOAM_REFERENCE_GEOMETRY . +EQ.0.0: off, +EQ.1.0: on. +Specimen gauge length, see Figure M27-1. +Specimen width, see Figure M27-1. +Specimen thickness, see Figure M27-1. +Load curve ID, see DEFINE_CURVE, giving the force versus +actual change in gauge length. See also Figure M27-2 for an +alternative definition. +REF +SGL +SW +ST +LCID +Remarks: +The constants can be defined directly or a least squares fit can be performed if the +uniaxial data (SGL, SW, ST and LCID) is available. If a least squares fit is chosen, then +the terms to be included in the energy functional are flagged by setting their +corresponding coefficients to unity. If all coefficients are zero the default is to use only +the terms involving I1 and I2. C100 defaults to unity if the least square fit is used. +The strain energy functional, U, is defined in terms of the input constants as: +𝑈 = 𝐶100𝐼1 + 𝐶200𝐼1 +2 + 𝐶300𝐼1 +3 + 𝐶400𝐼1 +4 + 𝐶110𝐼1𝐼2 + 𝐶210𝐼1 +2𝐼2 + 𝐶010𝐼2 + 𝐶020𝐼2 +2 + 𝑓 (𝐽) +where the invariants can be expressed in terms of the deformation gradient matrix, Fij, +and the Green-St. Venant strain tensor, Eij : +𝐽 = ∣𝐹𝑖𝑗∣ +𝐼1 = 𝐸𝑖𝑖 +𝐼2 = +2! +𝑖𝑗 𝐸𝑝𝑖𝐸𝑞𝑗 +𝛿𝑝𝑞 +The derivative of U with respect to a component of strain gives the corresponding +component of stress +here, Sij, is the second Piola-Kirchhoff stress tensor. +𝑆𝑖𝑗 = +∂𝑈 +∂𝐸𝑖𝑗 +The load curve definition that provides the uniaxial data should give the change in +gauge length, ΔL, and the corresponding force. In compression both the force and the +change in gauge length must be specified as negative values. In tension the force and +change in gauge length should be input as positive values. The principal stretch ratio in +the uniaxial direction, λ1, is then given by +𝜆 = +𝐿𝑜 + Δ𝐿 +𝐿𝑜 +Alternatively, the stress versus strain curve can also be input by setting the gauge +length, thickness, and width to unity and defining the engineering strain in place of the +change in gauge length and the nominal (engineering) stress in place of the force, see +Figure M27-2 The least square fit to the experimental data is performed during the +initialization phase and is a comparison between the fit and the actual input is provided +in the printed file. It is a good idea to visually check the fit to make sure it is acceptable. +The coefficients C100 - C020 are also printed in the output file. +*MAT_LAMINATED_GLASS +This is Material Type 32. With this material model, a layered glass including polymeric +layers can be modeled. Failure of the glass part is possible. See notes below. +Card 1 +1 +Variable +MID +Type +A8 +Card 2 +1 +2 +RO +F +2 +3 +EG +F +3 +Variable +PRP +SYP +ETP +Type +F +F +F +4 +5 +6 +7 +PRG +SYG +ETG +EFG +F +4 +F +5 +F +6 +F +7 +8 +EP +F +8 +Integration Point Cards. Define 1-4 cards specifying up to 32 values. If less than 4 +cards are input, reading is stopped by a “*” control card. +Card 3 +Variable +1 +F1 +Type +F +2 +F2 +F +3 +F3 +F +4 +F4 +F +5 +F5 +F +6 +F6 +F +7 +F7 +F +8 +F8 +F +VARIABLE +DESCRIPTION +MID +RO +EG +PRG +SYG +ETG +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus for glass +Poisson’s ratio for glass +Yield stress for glass +Plastic hardening modulus for glass +DESCRIPTION +*MAT_032 +EFG +EP +PRP +SYP +ETP +Plastic strain at failure for glass +Young’s modulus for polymer +Poisson’s ratio for polymer +Yield stress for polymer +Plastic hardening modulus for polymer +F1, …, FN +Integration point material: +fn = 0.0: glass, +fn = 1.0: polymer. +A user-defined integration rule must be specified, see *INTEGRA- +TION_SHELL. See remarks below. +Remarks: +Isotropic hardening for both materials is assumed. The material to which the glass is +bonded is assumed to stretch plastically without failure. A user defined integration rule +specifies the thickness of the layers making up the glass. Fi defines whether the +integration point is glass (0.0) or polymer (1.0). The material definition, Fi, has to be +given for the same number of integration points (NIPTS) as specified in the rule. A +maximum of 32 layers is allowed. +If the recommended user defined rule is not defined, the default integration rules are +used. The location of the integration points in the default rules are defined in the *SEC- +TION_SHELL keyword description. +*MAT_BARLAT_ANISOTROPIC_PLASTICITY +This is Material Type 33. This model was developed by Barlat, Lege, and Brem [1991] +for modeling anisotropic material behavior in forming processes. The finite element +implementation of this model is described in detail by Chung and Shah [1992] and is +used here. It is based on a six parameter model, which is ideally suited for 3D +continuum problems, see notes below. For sheet forming problems, material 36 based +on a 3-parameter model is recommended. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +Variable +Type +1 +A +F + Card 3 +1 +2 +RO +F +2 +B +F +2 +Variable +AOPT +BETA +Type +F +F + Card 4 +Variable +1 +XP +Type +F +2 +YP +F +3 +E +F +3 +C +F +3 +3 +ZP +F +4 +PR +F +4 +F +F +4 +4 +A1 +F +5 +K +F +5 +G +F +5 +5 +A2 +F +6 +E0 +F +6 +H +F +6 +6 +A3 +F +7 +N +F +7 +LCID +F +7 +8 +M +F +8 +8 +7 +Card 5 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +E +PR +K +EO +N +M +A +B +C +F +G +H +LCID +Mass density. +Young’s modulus, 𝐸. +Poisson’s ratio, 𝜈. +𝑘, strength coefficient, see notes below. +𝜀0, strain corresponding to the initial yield, see notes below. +𝑛, hardening exponent for yield strength. +𝑚, flow potential exponent in Barlat’s Model. +𝑎, anisotropy coefficient in Barlat’s Model. +𝑏, anisotropy coefficient in Barlat’s Model. +𝑐, anisotropy coefficient in Barlat’s Model. +𝑓 , anisotropy coefficient in Barlat’s Model. +𝑔, anisotropy coefficient in Barlat’s Model. +ℎ, anisotropy coefficient in Barlat’s Model. +Option load curve ID defining effective stress versus effective +plastic strain. If nonzero, this curve will be used to define the +yield stress. The load curve is implemented for solid elements +only. +*MAT_BARLAT_ANISOTROPIC_PLASTICITY +DESCRIPTION +AOPT +Material axes option: +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then, for shells only, rotated about +the shell element normal by an angle BETA.. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center, this is the 𝑎-direction. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +offsetting the material axes by an angle, BETA, from a +line determined by taking the cross product of the vec- +tor 𝐯 with the normal to the plane of the element. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). +BETA +Material angle in degrees for AOPT = 1 (shells only) and +AOPT = 3, may be overridden on the element card, see *ELE- +MENT_SHELL_BETA or *ELEMENT_SOLID_ORTHO. +MACF +Material axes change flag for brick elements: +EQ.1: No change, default, +EQ.2: switch material axes 𝑎 and 𝑏, +EQ.3: switch material axes 𝑎 and 𝑐, +EQ.4: switch material axes 𝑏 and 𝑐. +XP, YP, ZP +Coordinates of point 𝐩 for AOPT = 1. +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3. +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2. +Remarks: +The yield function Φ is defined as: +Φ = |𝑆1 − 𝑆2|𝑚 + ∣𝑆2 − 𝑆3∣𝑚 + ∣𝑆3 − 𝑆1∣𝑚 = 2𝜎̅̅̅̅̅ 𝑚 +where 𝜎̅̅̅̅̅ is the effective stress and 𝑆𝑖=1,2,3 are the principal values of the symmetric +matrix 𝑆𝛼𝛽, +𝑆𝑥𝑥 = [𝑐(𝜎𝑥𝑥 − 𝜎𝑦𝑦) − 𝑏(𝜎𝑧𝑧 − 𝜎𝑥𝑥)] 3⁄ +𝑆𝑦𝑦 = [𝑎(𝜎𝑦𝑦 − 𝜎𝑧𝑧) − 𝑐(𝜎𝑥𝑥 − 𝜎𝑦𝑦)] 3⁄ +𝑆𝑧𝑧 = [𝑏(𝜎𝑧𝑧 − 𝜎𝑥𝑥) − 𝑎(𝜎𝑦𝑦 − 𝜎𝑧𝑧)] 3⁄ +𝑆𝑦𝑧 = 𝑓 𝜎𝑦𝑧 +𝑆𝑧𝑥 = 𝑔𝜎𝑧𝑥 +𝑆𝑥𝑦 = ℎ𝜎𝑥𝑦 +The material constants a, b, c, f, g and h represent anisotropic properties. When +𝑎 = 𝑏 = 𝑐 = 𝑓 = 𝑔 = ℎ = 1, +the material is isotropic and the yield surface reduces to the Tresca yield surface for +𝑚 = 1 and von Mises yield surface for 𝑚 = 2 or 4. +For face centered cubic (FCC) materials 𝑚 = 8 is recommended and for body centered +cubic (BCC) materials 𝑚 = 6 is used. The yield strength of the material is +𝜎𝑦 = 𝑘(𝜀𝑝 + 𝜀0)𝑛 +where 𝜀0 is the strain corresponding to the initial yield stress and 𝜀𝑝 is the plastic strain. +*MAT_BARLAT_YLD96 +This is Material Type 33. This model was developed by Barlat, Maeda, Chung, +Yanagawa, Brem, Hayashida, Lege, Matsui, Murtha, Hattori, Becker, and Makosey +[1997] for modeling anisotropic material behavior in forming processes in particular for +aluminum alloys. This model is available for shell elements only. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +Variable +1 +E0 +Type +F + Card 3 +Variable +1 +C1 +Type +F + Card 4 +1 +2 +RO +F +2 +N +F +2 +C2 +F +2 +3 +E +F +3 +ESR0 +F +3 +C3 +F +3 +4 +PR +F +4 +M +F +4 +C4 +F +4 +5 +K +F +5 +HARD +F +5 +AX +F +5 +6 +7 +8 +6 +A +F +6 +AY +F +6 +7 +8 +7 +8 +AZ0 +AZ1 +F +7 +F +8 +Variable +AOPT +BETA +Type +F +1 +2 +3 +Variable +Type + Card 6 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +*MAT_033_96 +7 +8 +7 +8 +6 +A3 +F +6 +D3 +F +4 +A1 +F +4 +D1 +F +5 +A2 +F +5 +D2 +F +DESCRIPTION + VARIABLE +MID +RO +E +PR +K +EO +N +ESR0 +M +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus, 𝐸. +Poisson’s ratio,𝜈. +𝑘, strength coefficient or a in Voce, see notes below. +𝜀0, strain corresponding to the initial yield or b in Voce, see notes +below. +𝑛, hardening exponent for yield strength or c in Voce. +𝜀SR0, in powerlaw rate sensitivity. +𝑚, exponent for strain rate effects +HARD +Hardening option: +LT.0.0: absolute value defines the load curve ID. +EQ.1.0: powerlaw +EQ.2.0: Voce +A +C1 +Flow potential exponent. +𝑐1, see equations below. +VARIABLE +DESCRIPTION +C2 +C3 +C4 +AX +AY +AZ0 +AZ1 +𝑐2, see equations below. +𝑐3, see equations below. +𝑐4, see equations below. +𝑎𝑥, see equations below. +𝑎𝑦, see equations below. +𝑎𝑧0, see equations below. +𝑎𝑧1, see equations below. +AOPT +Material axes option: +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the shell ele- +ment normal by an angle BETA. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +offsetting the material axes by an angle, BETA, from a +line determined by taking the cross product of the vec- +tor 𝐯 with the normal to the plane of the element. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). +BETA +Material angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA.. +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3. +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2. +*MAT_033_96 +The yield stress 𝜎𝑦 is defined three ways. The first, the Swift equation, is given in terms +of the input constants as: +𝜎𝑦 = 𝑘(𝜀0 + 𝜀𝑝)𝑛 ( +𝜀̇ +𝜀𝑆𝑅0 +) +The second, the Voce equation, is defined as: +𝜎𝑦 = 𝑎 − 𝑏𝑒−𝑐𝜀𝑝 +and the third option is to give a load curve ID that defines the yield stress as a function +of effective plastic strain. The yield function Φ is defined as: +Φ = 𝛼1|𝑠1 − 𝑠2|𝑎 + 𝛼2∣𝑠2 − 𝑠3∣𝑎 + 𝛼3∣𝑠3 − 𝑠1∣𝑎 = 2𝜎𝑦 +𝑎 +where 𝑠𝑖 is a principle component of the deviatoric stress tensor where in vector +notation: +and 𝐋 is given as +𝐬 = 𝐋𝛔 +𝐋 = +𝑐2 + 𝑐3 +−𝑐3 +−𝑐2 +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +−𝑐3 +𝑐3 + 𝑐1 +−𝑐1 +3 +−𝑐2 +−𝑐1 +𝑐1 + 𝑐2 +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +𝑐4⎦ +A coordinate transformation relates the material frame to the principle directions of 𝐬 is +used to obtain the 𝛼𝑘 coefficients consistent with the rotated principle axes: +2 + 𝛼𝑦𝑝2𝑘 +2 +2 + 𝛼𝑧𝑝3𝑘 +𝛼𝑘 = 𝛼𝑥𝑝1𝑘 +𝛼𝑧 = 𝛼𝑧0cos2(2𝛽) + 𝛼𝑧1sin2(2𝛽) +where 𝑝𝑖𝑗 are components of the transformation matrix. The angle 𝛽 defines a measure +of the rotation between the frame of the principal value of 𝐬 and the principal +anisotropy axes. +*MAT_FABRIC +This is Material Type 34. This material is especially developed for airbag materials. +The fabric model is a variation on the layered orthotropic composite model of material +22 and is valid for 3 and 4 node membrane elements only. +In addition to being a constitutive model, this model also invokes a special membrane +element formulation which is more suited to the deformation experienced by fabrics +under large deformation. For thin fabrics, buckling can result in an inability to support +compressive stresses; thus a flag is included for this option. A linearly elastic liner is +also included which can be used to reduce the tendency for these elements to be +crushed when the no-compression option is invoked. In LS-DYNA versions after 931 +the isotropic elastic option is available. +2 +RO +F +2 +3 +EA +F +3 + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +Variable +GAB +Type +F +Remarks + Card 3 +1 +2 +3 +4 +EB +F +4 +CSE +F +1 +4 +5 +6 +7 +8 +PRBA +PRAB +F +6 +F +7 +8 +PRL +LRATIO +DAMP +F +4 +6 +F +4 +7 +F +8 +5 +EL +F +4 +5 +Variable +AOPT +FLC/X2 +FAC/X3 +ELA +LNRC +FORM +FVOPT +TSRFAC +Type +F +Remarks +F +2 +F +2 +F +3 +F +4 +F +11 +F +9 +F +10 +BETA +ISREFG +F +I +8 +7 +RL +F +*MAT_FABRIC +*MAT_034 + Card 4 +1 +2 +3 +Variable +RGBRTH +A0REF +Type +F +F + Card 5 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +A1 +F +4 +5 +A2 +F +5 +6 +A3 +F +6 +7 +X0 +F +7 +8 +X1 +F +8 +Additional card for FORM = 4, 14, or -14. + Card 6 +1 +2 +3 +4 +5 +6 +Variable +LCA +LCB +LCAB +LCUA +LCUB +LCUAB +Type +I +I +I +I +I +I +Additional card for FORM = -14. + Card 7 +1 +2 +Variable +LCAA +LCBB +Type +I +I +3 +H +F +4 +DT +F +5 +6 +7 +8 +ECOAT +SCOAT +TCOAT +F +F +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +VARIABLE +DESCRIPTION +EA +EB +PRBA +PRAB +GAB +Young’s modulus - longitudinal direction. For an isotopic elastic +fabric material only EA and PRBA are defined and are used as the +isotropic Young’s modulus and Poisson’s ratio, respectively. The +input for the fiber directions and liner should be input as zero for +the isotropic elastic fabric +Young’s modulus - transverse direction, set to zero for isotropic +elastic material. +𝜈𝑏𝑎, Minor Poisson’s ratio ba direction. +𝜈𝑎𝑏, Major Poisson’s ratio ab direction. +𝐺𝑎𝑏, shear modulus ab direction, set to zero for isotropic elastic +material. +CSE +Compressive stress elimination option : +EL +PRL +LRATIO +DAMP +AOPT +EQ.0.0: don’t eliminate compressive stresses, (default) +EQ.1.0: eliminate compressive stresses. This option does not +apply to the liner. +Young’s modulus for elastic liner (required if LRATIO > 0). +Poisson’s ratio for elastic liner (required if LRATIO > 0). +A non-zero value activates the elastic liner and defines the ratio of +liner thickness to total fabric thickness (optional). +Rayleigh damping coefficient. A 0.05 coefficient is recommended +corresponding to 5% of critical damping. Sometimes larger values +are necessary. +Material axes option . Also, please refer to Remark 5 for +additional information specific to fibre directions for fabrics: +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the element +normal by an angle BETA. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +*MAT_034 +DESCRIPTION +EQ.3.0: locally orthotropic material axes determined by rotating +the material axes about the element normal by an angle, +BETA, from a line in the plane of the element defined by +the cross product of the vector v with the element nor- +mal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +If X0 is between 0 and 1 (exclusive) then +X2 (FLC) +X3 (FAC) +X2 is a coefficient of the porosity from the equation in Anagonye +and Wang [1999]. +X3 is a coefficient of the porosity equation of Anagonye and Wang +[1999]. +Else If X0 = 0 or -1 then (sets meaning of the abscissa for load curve cases) +FLC (X2) +Optional porous leakage flow coefficient. +GE.0: Porous leakage flow coefficient. +LT.0: |FLC| is interpreted as a load curve ID defining FLC as a +function of time. +If FVOPT < 7 then (sets meaning of the mantissa for load curve case) +FAC (X3) +Optional characteristic fabric parameter. +GE.0: Characteristic fabric parameter +LT.0: |FAC| is interpreted as a load curve ID defining FAC as a +function of absolute pressure. +VARIABLE +DESCRIPTION +Else if FVOPT ≥ 7 then (sets meaning of the mantissa for load curve case) +FAC (X3) +Optional characteristic fabric parameter. +GE.0: Characteristic fabric parameter +LT.0: |FAC| is interpreted as a load curve ID giving leakage +volume flux rate versus absolute pressure. The volume +flux (per area) rate (per time) has the unit of +𝑑(volflux) dt⁄ ≈ [length]3 ([length]2[time]) +, +≈ [length] [time] +⁄ +⁄ +equivalent to relative porous gas speed. +End if +Else if X0 = 1 (sets meaning of the abscissa for load curve cases) +FLC (X2) +Optional porous leakage flow coefficient. +GE.0: Porous leakage flow coefficient. +LT.0: |FLC| is interpreted as a load curve curve ID defining FLC +versus the stretching ratio defined as 𝑟𝑠 = 𝐴/𝐴0. See notes +below. +If FVOPT > 7 then (sets meaning of the mantissa for load curve case) +FAC (X3) +Optional characteristic fabric parameter. +GE.0: Characteristic fabric parameter +LT.0: |FAC| is interpreted as a load curve defining FAC versus +the pressure ratio 𝑟𝑝 = 𝑃ai𝑟/𝑃bag. See Remark 2 below. +DESCRIPTION +*MAT_034 +Else if FVOPT ≥ 7 then (sets meaning of the mantissa for load curve case) +FAC (X3) +Optional characteristic fabric parameter. +GE.0: Characteristic fabric parameter +LT.0: |FAC| is interpreted as a load curve defining leakage +volume +flux rate versus the pressure ratio defined +as 𝑟𝑝 = 𝑃air/𝑃bag. See Remark 2 below. The volume flux +(per area) rate (per time) has the unit of +𝑑(volflux) dt⁄ ≈ [length]3 ([length]2[time]) +, +≈ [length] [time] +⁄ +⁄ +equivalent to relative porous gas speed. +End if +End if +ELA +Effective leakage area for blocked fabric, ELA : +LT.0.0: |ELA| is the load curve ID of the curve defining ELA +versus time. The default value of zero assumes that no +leakage occurs. A value of .10 would assume that 10% of +the blocked fabric is leaking gas. +LNRC +Flag to turn off compression in liner until the reference geometry is +reached, i.e., the fabric element becomes tensile. +EQ.0.0: off. +EQ.1.0: on. +FORM +Flag to modify membrane formulation for fabric material: +EQ.0.0: default. Least costly and very reliable. +EQ.1.0: +invariant local membrane coordinate system +EQ.2.0: Green-Lagrange strain formulation +EQ.3.0: +EQ.4.0: +large strain with nonorthogonal material angles. See +Remark 5. +large strain with nonorthogonal material angles and +nonlinear stress strain behavior. Define optional load +curve IDs on optional card. +EQ.12.0: Enhanced version of formulation 2. See Remark 11. +VARIABLE +DESCRIPTION +EQ.13.0: Enhanced version of formulation 3. See Remark 11. +EQ.14.0: Enhanced version of formulation 4. See Remark 11. +EQ.-14.0: Same as formulation 14, but invokes reading of card 7. +See Remark 14. +EQ.24.0: Enhanced version of formulation 14. See Remark 11. +FVOPT +Fabric venting option. +EQ.1: Wang-Nefske formulas for venting through an orifice are +used. Blockage is not considered. +EQ.2: Wang-Nefske formulas for venting through an orifice are +used. Blockage of venting area due to contact is consid- +ered. +EQ.3: Leakage formulas of Graefe, Krummheuer, and Siejak +[1990] are used. Blockage is not considered. +EQ.4: Leakage formulas of Graefe, Krummheuer, and Siejak +[1990] are used. Blockage of venting area due to contact is +considered. +EQ.5: Leakage formulas based on flow through a porous media +are used. Blockage is not considered. +EQ.6: Leakage formulas based on flow through a porous media +are used. Blockage of venting area due to contact is con- +sidered. +EQ.7: Leakage is based on gas volume outflow versus pressure +load curve [Lian, 2000]. Blockage is not considered. Abso- +lute pressure is used in the porous-velocity-versus- +pressure load curve, given as FAC in the *MAT_FABRIC +card. +EQ.8: Leakage is based on gas volume outflow versus pressure +load curve [Lian 2000]. Blockage of venting or porous area +due to contact is considered. Absolute pressure is used in +the porous-velocity-versus-pressure load curve, given as +FAC in the *MAT_FABRIC card. +DESCRIPTION +TSRFAC +Strain restoration factor +*MAT_034 +LT.0: +|TSRFAC| is the ID of a curve defining TSRFAC +versus time.. +GT.0 and LT.1: TSRFAC applied from time 0. +GE.1: +TSRFAC is the ID of a curve that defines +TSRFAC versus time using an alternate method +(not available for FORM = 0 or 1). +RGBRTH +Material dependent birth time of airbag reference geometry. Non- +zero RGBRTH overwrites the birth time defined in the *AIRBAG_- +REFERENCE_GEOMETRY_BIRTH section. RGBRTH also applies +to reference geometry defined by *AIRBAG_SHELL_REFER- +ENCE_GEOMETRY. +A0REF +Calculation option of initial area, A0, used for airbag porosity +leakage calculation. +EQ.0.: default. Use the initial geometry defined in *NODE. +EQ.1.: Use +the +reference +geometry +*AIRBAG_REFERENCE_GEOMETRY +*AIRBAG_SHELL_REFERENCE_GEOMETRY. +defined +in +or +A1, A2, A3 +Components of vector a for AOPT = 2. +X0, X1 +Coefficients of Anagonye and Wang [1999] porosity equation for +the leakage area: 𝐴leak = 𝐴0(𝑋0 + 𝑋1𝑟𝑠 + 𝑋2𝑟𝑝 + 𝑋3𝑟𝑠𝑟𝑝) +X0.EQ.-1: Compressing seal vent option. The leakage area is +evaluated as 𝐴leak = max(𝐴current − 𝐴0, 0). +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3. +BETA +ISREFG +Material angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA. +Initialize stress by *AIRBAG_REFERENCE_GEOMETRY. This +option applies only to FORM = 12. Note that *MAT_FABRIC +cannot be initialized using a dynain file because *INITIAL_- +STRESS_SHELL is not applicable to *MAT_FABRIC. +EQ.0.0: default. Not active. +EQ.1.0: active +LCA +LCB +LCAB +LCUA +LCUB +LCUAB +RL +LCAA +*MAT_FABRIC +DESCRIPTION +Load curve or table ID. Load curve ID defines the stress versus +uniaxial strain along the a-axis fiber. Table ID defines for each +strain rate a load curve representing stress versus uniaxial strain +along the a-axis fiber. Available for FORM = 4, 14, –14, and 24 +only, table allowed only for form = -14. If zero, EA is used. For +FORM = 14, -14, and 24, this curve can be defined in both tension +and compression, see Remark 6 below. +Load curve or table ID. Load curve ID defines the stress versus +uniaxial strain along the b-axis fiber. Table ID defines for each +strain rate a load curve representing stress versus uniaxial strain +along the b-axis fiber. Available for FORM = 4, 14, -14, and 24 +only, table allowed only for form = -14. If zero, EB is used. For +FORM = 14, -14, and 24, this curve can be defined in both tension +and compression, see Remark 6 below. +Load curve ID for shear stress versus shear strain in the ab-plane; +available for FORM = 4, 14, -14, and 24 only. If zero, GAB is used. +Unload/reload curve ID for stress versus strain along the a-axis +fiber; available for FORM = 4, 14, -14, and 24 only. If zero, LCA is +used. +Unload/reload curve ID for stress versus strain along the b-axis +fiber; available for FORM = 4, 14, -14, and 24 only. If zero, LCB is +used. +Unload/reload curve ID for shear stress versus shear strain in the +ab-plane; available for FORM = 4, 14, -14, and 24 only. If zero, +LCAB is used. +Optional reloading parameter for FORM = 14 and 24. Values +between 0.0 (reloading on unloading curve-default) and 1.0 +(reloading on a minimum linear slope between unloading curve +and loading curve) are possible. +Load curve or table ID. Load curve ID defines the stress along the +a-axis fiber versus biaxial strain. Table ID defines for each +directional strain rate a load curve representing stress along the a- +axis fiber versus biaxial strain. Available for FORM=–14 only, if +zero, LCA is used. +LCBB +*MAT_034 +DESCRIPTION +Load curve or table ID. Load curve ID defines the stress along the +b-axis fiber versus biaxial strain. Table ID defines for each +directional strain rate a load curve representing stress along the b- +axis fiber versus biaxial strain. Available for FORM=–14 only, if +zero, LCB is used. +H +DT +Normalized hysteresis parameter between 0 and 1. +Strain rate averaging option. +EQ.0.0: Strain rate is evaluated using a running average. +LT.0.0: Strain rate is evaluated using average of last 11 time +steps. +GT.0.0: Strain rate is averaged over the last DT time units. +ECOAT +Young’s modulus of coat material, see Remark 14. +SCOAT +Yield stress of coat material, see Remark 14. +TCOAT +Thickness of coat material, may be positive or negative, see +Remark 14. +Remarks: +1. The Compressive Stress Elimination Option for Airbag Wrinkling. Setting +CSE=1 switches off compressive stress in the fabric, thereby eliminating wrin- +kles. Without this “no compression” option the geometry of the bag’s wrinkles +control the amount of mesh refinement. In eliminating the wrinkles, this fea- +ture reduces the number of elements needed to attain an accurate solution. +The no compression option can allow elements to collapse to a line which can +lead to elements becoming tangled. The elastic liner option is one way to add +some stiffness in compression to prevent this, see Remark 4. Alternatively, +when using fabric formulations 14, -14, or 24 tangling can be re- +duced by defining stress/strain curves that include negative strain and stress +values. See Remark 6.use +2. Porosity. The parameters FLC and FAC are optional for the Wang-Nefske and +Hybrid inflation models. It is possible for the airbag to be constructed of multi- +ple fabrics having different values for porosity and permeability. Typically, +FLC and FAC must be determined experimentally and their variations in time +or with pressure are optional to allow for maximum flexibility. +3. Effects of Airbag-Structure Interaction on Porosity. To calculate the leakage +of gas through the fabric it is necessary to accurately determine the leakage +area. The dynamics of the airbag may cause the leakage area to change during +the course of the simulation. In particular, the deformation may change the +leakage area, but the leakage area may also decrease when the contact between +the airbag and the structure blocks the flow. LS-DYNA can check the interac- +tion of the bag with the structure and split the areas into regions that are +blocked and unblocked depending on whether the regions are in or not in con- +tact, respectively. Blockage effects may be controlled with the ELA field. +4. Elastic Liner. An optional elastic liner can be defined using EL, PRL and +LRATIO. The liner is an isotropic layer that acts in both tension and compres- +sion. However, setting, LNRC to 1.0 eliminates compressive stress in the liner +until both principle stresses are tensile. The compressive stress elimination +option, CSE=1, has no influence on the liner behavior. +5. Fiber Axes. For formulations 0, 1, and 2, the 𝑎-axis and 𝑏-axis fiber +directions are assumed to be orthogonal and are completely defined by the materi- +al axes option, AOPT=0, 2, or 3. For FORM=3, 4, 13, or 14, the fiber directions +are not assumed orthogonal and must be specified using the ICOMP=1 option on +*SECTION_SHELL. Offset angles should be input into the B1 and B2 fields +used normally for integration points 1 and 2. The 𝑎-axis and 𝑏-axis directions +will then be offset from the 𝑎-axis direction as determined by the material axis +option, AOPT=0, 2, or 3. +6. Stress vs. Strain Curves. For formulations 4, 14, -14, and 24, 2nd +Piola-Kirchhoff stress vs. Green’s strain curves may be defined for 𝑎-axis, 𝑏- +axis, and shear stresses for loading and also for unloading and reloading. Al- +ternatively, the 𝑎-axis and 𝑏-axis curves can be input using engineering stress +vs. strain by setting DATYP = -2 on *DEFINE_CURVE. +Additionally, for formulations 14, -14, and 24, the uniaxial loading curves LCA +and LCB may be defined for negative values of strain and stress, i.e., a straight- +forward extension of the curves into the compressive region. This is available +in order to model the compressive stresses resulting from tight folding of air- +bags. +The 𝑎-axis and 𝑏-axis stress follow the curves for the entire defined strain region +and if compressive behavior is desired the user should preferably make sure the +curve covers all strains of interest. For strains below the first point on the +curve, the curve is extrapolated using the stiffness from the constant values, EA +or EB. +Shear stress/strain behavior is assumed symmetric and curves should be de- +fined for positive strain only. However, formulations 14, -14, and 24 allow the +extending of the curves in the negative strain region to model asymmetric be- +havior. The asymmetric option cannot be used with a shear stress unload +curve. If a load curve is omitted, the stress is calculated from the appropriate +constant modulus, EA, EB, or GAB. +7. Yield Behavior. When formulations 4, 14, -14, and 24 are used +with loading and unloading curves the initial yield strain is set equal to the +strain of the first point in the load curve having a stress greater than zero. +When the current strain exceeds the yield strain, the stress follows the load +curve and the yield strain is updated to the current strain. When unloading +occurs, the unload/reload curve is shifted along the x-axis until it intersects the +load curve at the current yield strain. When using unloading curves, compres- +sive stress elimination should be active to prevent the fibers from developing +compressive stress during unloading when the strain remains tensile. To use +this option, the unload curve should have a nonnegative second derivate so that the +curve will shift right as the yield stress increases. +If LCUA, LCUB, or LCUAB are input with negative values, then unloading is +handled differently. Instead of shifting the unload curve along the 𝑥-axis, the +curve is stretched in both the 𝑥-direction and 𝑦-direction such that the first point +remains anchored at (0,0) and the initial intersection point of the curves is +moved to the current yield point. This option guarantees the stress remains +tensile while the strain is tensile so compressive stress elimination is not neces- +sary. To use this option the unload curve should have an initial slope less steep than +the load curve, and should steepen such that it intersects the load curve at some positive +strain value. +8. Shear Unload-Reload, Fabric Formulation, and LS-DYNA version. With +release 6.0.0 of version 971, LS-DYNA changed the way that unload/reload +curves for shear stress-strain relations are interpreted. Let f be the shear stress +unload-reload curve LCUAB. Then, +where the scale factors 𝑐1 and 𝑐2 depend on the fabric form and +version of LS-DYNA. +𝜎𝑎𝑏 = 𝑐2𝑓 (𝑐1𝜀𝑎𝑏) +Fabric form +4 +14 and -14 +24 +LS971 R5.1.0 and earlier +LS971 R6.0.0 to R7.0 +LS-DYNA R7.1 and later +𝑐1 +2 +2 +2 +𝑐2 +1 +1 +1 +𝑐1 +2 +1 +1 +𝑐2 +1 +2 +2 +𝑐1 +𝑐2 +- +- +1 +- +- +1 +When switching fabric forms or versions, the curve scale factors SFA and SFO +on *DEFINE_CURVE can be used to offset this behavior. +9. Per Material Venting Option. The FVOPT flag allows an airbag fabric venting +equation to be assigned to a material. The anticipated use for this option is to +allow a vent to be defined using FVOPT=1 or 2 for one material and fabric leak- +age to be defined for using FVOPT=3, 4, 5, or 6 for other materials. In order to +use FVOPT, a venting option must first be defined for the airbag using the OPT +parameter on *AIRBAG_WANG_NEFSKE or *AIRBAG_HYBRID. If OPT=0, +then FVOPT is ignored. If OPT is defined and FVOPT is omitted, then FVOPT +is set equal to OPT. +10. TSRFAC option to restore element strains. Airbags that use a reference +geometry will typically have nonzero strains at the start of the calculation. To +prevent such initial strains from prematurely opening an airbag, initial strains +are stored and subtracted from the measured strain throughout the calculation. +𝝈 = 𝑓 (𝜺 − 𝜺initial) +• Fabric formulations 2, 3, and 4 subtract off only the initial ten- +sile strains so these forms are typically used with CSE = 1 and LNRC = 1. +• Fabric formulations 12, 13, 14, -14, and 24 subtract off the total initial +strains so these forms may be used with CSE = 0 or 1 and LNRC = 0 or 1. +A side effect of this strain modification is that airbags may not achieve the +correct volume when they open. Therefore, the TSRFAC option is imple- +mented to reduce the stored initial strain values over time thereby restor- +ing the total stain which drives the airbag towards the correct volume. +During each cycle, the stored initial strains are scaled by (1.0 − TSRFAC). A +small value on the order of 0.0001 is typically sufficient to restore the strains in +a few milliseconds of simulation time. +The adjustment to restore initial strain is then, +𝝈 = 𝑓 (𝜺 − 𝜺adjustment) +𝛆adjustment = εinitial ∏[1 − TSFRAC] +. +a) Time Dependent TSRFAC. When TSRFAC ˂ 0, |TSRFAC| becomes the ID of +a curve that defines TSRFAC as a function of time. To delay the effect of +TSRFAC, the curve ordinate value should be initially zero and should +ramp up to a small number to restore the strain at an appropriate time +during the simulation. The adjustment to restore initial strain is then, +𝛆adjustment(𝑡𝑖) = εinitial ∏[1 − TSFRAC(𝑡𝑖)] +. +To prevent airbags from opening prematurely, it is recommended to use +the load curve option of TSRFAC to delay the strain restoration until the +airbag is partially opened due to pressure loading. +b) Alternate Time Dependent TSRFAC. For fabric formulations 2 and higher, a +second curve option is invoked by setting TSRFAC≥1 where TSRFAC is +again the ID of a curve that defines TSRFAC versus time. Like the first +curve option, the stored initial strain values are scaled by (1.0 − TSRFAC), +but the modified initial strains are not saved, so the effect of TSRFAC does +not accumulate. In this case the adjustment to eliminate initial strain +𝛆adjustment(𝑡𝑖) = [1 − TSFRAC(𝑡𝑖)]𝛆initial. +Therefore, the curve should ramp up from zero to one to fully restore the +strain. This option gives the user better control of the rate of restoring +the strain as it is a function of time rather than solution time step. +11. Enhancements to the Material Formulations. Material formulations 12, 13, and 14 are enhanced versions of formulations 2, 3, and 4, respec- +tively. The most notable difference in their behavior is apparent when a refer- +ence geometry is used for the fabric. As discussed in Remark 10, the strain is +modified to prevent initial strains from prematurely opening an airbag at the +start of a calculation. +Formulations 2, 3, and 4 subtract the initial tensile strains, while the enhanced +formulations subtract the total initial strains. Therefore, the enhanced formula- +tions can be used without setting CSE = 1 and LNRC = 1 since compressive +stress cutoff is not needed to prevent initial airbag movement. Formulations 2, +3, and 4 need compressive stress cutoff when used with a reference geometry or +they can generate compressive stress at the start of a calculation. Available for +formulation 12 only, the ISREFG parameter activates an option to calculate the +initial stress by using a reference geometry. +Material formulation 24 is an enhanced version of formulation 14 implementing +a correction for Poisson’s effects when stress vs. strain curves are input for the +𝑎-fiber or 𝑏-fiber. Also, for formulation 24, the outputted stress and strain in the +S +A2 +A1 +loading +unloading +reloading +E +Figure M34-1. +elout or d3plot database files is engineering stress and strain rather than the 2nd +Piola Kirchoff and Green’s strain used by formulations other than 0 and 1. +12. Noise Reduction for the Strain Rate Measure. If tables are used, then the +strain rate measure is the time derivative of the Green-Lagrange strain in the +direction of interest. To suppress noise, the strain rate is averaged according to +the value of DT. If DT > 0, it is recommended to use a large enough value to +suppress the noise, while being small enough to not lose important information +in the signal. +13. Hysteresis. The hysteresis parameter H defines the fraction of dissipated +energy during a load cycle in terms of the maximum possible dissipated ener- +gy. Referring to the Figure M34-1, +𝐻 ≈ +𝐴1 +𝐴1 + 𝐴2 +14. Coating Feature for Additional Rotational Resistance. It is possible to +model coating of the fabric using a sheet of elastic-ideal-plastic material where +the Young’s modulus, yield stress and thickness is specified for the coat materi- +al. This will add rotational resistance to the fabric for a more realistic behavior +of coated fabrics. To read this parameters set FORM=-14, which adds an extra +card containing the three parameters ECOAT, SCOAT and TCOAT, corre- +sponding to the three coat material properties mentioned above. +The thickness, TCOAT, applies to both sides of the fabric. The coat material for +a certain fabric element deforms along with this and all elements connected to +this element, which is how the rotations are "captured". Note that unless +TCOAT is set to a negative value, the coating will add to the membrane stiff- +ness. For negative values of TCOAT the thickness is set to |TCOAT| and the +membrane contribution from the coating is suppressed. For this feature to +work, the fabric parts must not include any T-intersections, and all of the sur- +face normal vectors of connected fabric elements must point in the same direc- +tion. This option increases the computational complexity of this material. +15 +Fabric forms 12, 13, 14, -14, and 24 allow input of both the minor Poisson’s +ratio, 𝜈𝑏𝑎, and the major Poisson’s ratio, 𝜈𝑎𝑏. This allows asymmetric Poisson’s +behavior to be modelled. If the major Poisson’s ratio is left blank or input as +zero, then it will be calculated using 𝜈𝑎𝑏 = 𝜈𝑏𝑎 +. +𝐸𝑎 +𝐸𝑏 +*MAT_FABRIC_MAP +This is Material Type 34 in which the stress response is given exclusively by tables, or +maps, and where some obsolete features in *MAT_FABRIC have been deliberately +excluded to allow for a clean input and better overview of the model. + Card 1 +1 +Variable +MID +2 +RO +3 +4 +5 +6 +PXX +PYY +SXY +DAMP +Type +A8 +F +F + Card 2 +1 +Variable +FVOPT +Type +F + Card 3 +1 +2 +X0 +F +2 +3 +X1 +F +3 +F +4 +F +5 +F +6 +FLC/X2 +FAC/X3 +ELA +F +4 +F +5 +F +6 +7 +TH +F +7 +7 +Variable +ISREFG +CSE +SRFAC +BULKC +JACC +FXX +FYY +Type +F + Card 4 +1 +F +2 +F +3 +F +4 +Variable +AOPT +ECOAT +SCOAT +TCOAT +Type +F +F +F +F + Card 5 +Variable +1 +XP +Type +F +2 +YP +F +3 +ZP +F +4 +A1 +F +F +5 +5 +A2 +F +F +6 +6 +A3 +F +F +7 +7 +8 +2-246 (EOS) +LS-DYNA R10.0 +8 +8 +8 +DT +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F + VARIABLE +DESCRIPTION +*MAT_034M +7 +8 +BETA +F +MID +RO +PXX +PYY +SXY +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Table giving engineering local 𝑋𝑋-stress as function of engineering +local 𝑋𝑋-strain and 𝑌𝑌-strain. +Table giving engineering local 𝑌𝑌-stress as function of engineering +local 𝑌𝑌-strain and 𝑋𝑋-strain. +Curve giving local 2nd Piola-Kirchhoff XY-stress as function of local +Green 𝑋𝑌-strain. +DAMP +Damping coefficient for numerical stability. +TH +Table giving hysteresis factor 0 ≤ 𝐻 < 1 as function of engineering +local 𝑋𝑋-strain and 𝑌𝑌-strain. +GT.0.0: TH is table ID +LE.0.0: -TH is used as constant value for hysteresis factor +FVOPT +Fabric venting option, see *MAT_FABRIC. +X0, X1 +Fabric venting option parameters, see *MAT_FABRIC. +FLC/X2 +Fabric venting option parameter, see *MAT_FABRIC. +FAC/X3 +Fabric venting option parameter, see *MAT_FABRIC. +ELA +Fabric venting option parameter, see *MAT_FABRIC. +ISREFG +Initial stress by reference geometry. +EQ.0.0: Not active. +EQ.1.0: Active +VARIABLE +DESCRIPTION +CSE +Compressive stress elimination option. +EQ.0.0: Don’t eliminate compressive stresses, +EQ.1.0: Eliminate compressive stresses. +SRFAC +Load curve ID for smooth stress initialization when using a +reference geometry. +BULKC +Bulk modulus for fabric compaction. +JACC +FXX +FYY +Jacobian for the onset of fabric compaction. +Load curve giving scale factor of uniaxial stress in first material +direction as function of engineering strain rate. +Load curve giving scale factor of uniaxial stress in second material +direction as function of engineering strain rate. +DT +Time window for smoothing strain rates used for FXX and FYY. +AOPT +Material axes option, see *MAT_FABRIC. +ECOAT +Young’s modulus of coat material to include bending properties. +This together with the following two parameters (SCOAT and +TCOAT) encompass the same coating/bending feature as in +*MAT_FABRIC. Please refer to these manual pages and associated +remarks. +SCOAT +Yield stress of coat material, see *MAT_FABRIC. +TCOAT +Thickness of coat material, may be positive or negative, see +*MAT_FABRIC. +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3. +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2. +BETA +Material angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA. +*MAT_034M +This material model invokes a special membrane element formulation regardless of the +element choice. It is an anisotropic hyperelastic model where the 2nd Piola-Kirchhoff +stress 𝐒 is a function of the Green-Lagrange strain 𝐄 and possibly its history. Due to +anisotropy, this strain is transformed to obtain the strains in each of the fiber directions +𝐸𝑋𝑋 and 𝐸𝑌𝑌 together with the shear strain 𝐸𝑋𝑌. The associated stress components in +the local system are given as functions of the strain components +𝑆𝑋𝑋 = γ𝑆𝑋𝑋(𝐸𝑋𝑋, 𝐸𝑌𝑌)ϑ +𝑆𝑌𝑌 = γ𝑆𝑌𝑌(𝐸𝑌𝑌, 𝐸𝑋𝑋)ϑ +𝑆𝑋𝑌 = γ𝑆𝑋𝑌(𝐸𝑋𝑌)ϑ. +The factor 𝛾 is used for dissipative effects and is described in more detail later, for +TH = 0, 𝛾 = 1, and the function ϑ represents a strain rate scale factor also described +below, for FXX = FYY = 0 this factor is 1. While the shear relation is given directly +through the curve SXY, the tabular input of the fiber stress components PXX and PYY is +for the sake of convenience the engineering stress as function of engineering strain, i.e., +𝑃𝑋𝑋 = 𝑃𝑋𝑋(𝑒𝑋𝑋, 𝑒𝑌𝑌) +𝑃𝑌𝑌 = 𝑃𝑌𝑌(𝑒𝑌𝑌, 𝑒𝑋𝑋). +To this end, the following conversion formulae are used between stresses and strains +𝑒 = √1 + 2𝐸 − 1 +𝑆 = +1 + 𝑒 +these being applied in each of the two fiber directions. +Compressive stress elimination is optional through the CSE parameter, and when +activated the principal components of the 2nd Piola-Kirchhoff stress is restricted to +positive values. +If a reference geometry is used, then SRFAC is the identity of a curve that is a function +𝛼(𝑡) that should increase from zero to unity during a short time span, during which the +Green-Lagrange strain used in the formulae above is substituted for +𝐄̃ = 𝐄 − [1 − 𝛼(𝑡)]𝐄0, +where 𝑬0 is the strain at time zero. This is done in order to smoothly initialize the stress +resulting from using a reference geometry different from the geometry at time zero. +The factor 𝛾 is a function of the strain history and is initially set to unity, and depends, +more specifically, on the internal work 𝜖 given by the stress power +𝜖 ̇ = 𝐒 ∶ 𝐄̇. +Figure M34M-1. Cyclic loading model for hysteresis model H +The evolution of 𝛾 is related to the stress power in the sense that it will increase on +loading and decrease on unloading, and in this way introduce dissipation. The exact +mathematical formula is too complicated to reveal, but in essence the function looks like +𝛾 = { +1 − 𝐻(𝑒 ̅𝑋𝑋, 𝑒𝑌𝑌) + 𝐻(𝑒 ̅𝑋𝑋, 𝑒𝑌𝑌)exp[𝛽(𝜖 − 𝜖)] +1 − 𝐻(�� ̅𝑋𝑋, 𝑒𝑌𝑌)exp[−𝛽(𝜖 − 𝜖)] +𝜖 ̇ < 0 +𝜖 ̇ ≥ 0 +Here 𝜖 is the maximum attained internal work up to this point in time, 𝑒 ̅𝑋𝑋 and 𝑒 ̅𝑌𝑌 are +the engineering strain values associated with value. 𝐻(𝑒 ̅𝑋𝑋, 𝑒𝑌𝑌) is the hysteresis factor +defined by the user through the input parameter TH, it may or may not depend on the +strains. 𝛽 is a decay constant that depends on 𝑒 ̅𝑋𝑋 and 𝑒 ̅𝑌𝑌, and 𝜖 is the minimum +attained internal work at any point in time after 𝜖 was attained. In other words, on +unloading 𝛾 will exponentially decay to 1 − 𝐻 and on loading it will exponentially +grow to 1 and always be restricted by the lower and upper bounds, 1 − 𝐻 < 𝛾 ≤ 1. The +only thing the user needs to care about is to input a proper hysteresis factor 𝐻, and with +reference to a general loading/unloading cycle illustrated in figure M34M-1 below the +relation 1 − 𝐻 = 𝜖𝑢/𝜖𝑙 should hold. +To account for the packing of yarns in compression, a compaction effect is modeled by +adding a term to the strain energy function on the form +𝑊𝑐 = 𝐾𝑐𝐽 {𝑙𝑛 ( +𝐽𝑐 +) − 1} , for 𝐽 ≤ 𝐽𝑐 +where 𝐾𝑐 (BULKC) is a physical bulk modulus, 𝐽 = det(𝑭) is the jacobian of the +deformation and 𝐽𝑐 (JACC) is the critical jacobian for when the effect commences. Here +𝐅 is the deformation gradient. This gives a contribution to the pressure given by +𝑝 = 𝐾𝑐𝑙𝑛 ( +𝐽𝑐 +) , for 𝐽 ≤ 𝐽𝑐 +and thus prevents membrane elements from collapsing or inverting when subjected to +compressive loads. The bulk modulus 𝐾𝑐 should be selected with the slopes in the +stress map tables in mind, presumably some order of magnitude(s) smaller. +As an option, the local membrane stress can be scaled based on the engineering strain +rates via the function 𝜗 = 𝜗(𝑒 ̇, 𝐒). We set +𝑒 ̇ = max ( +𝜖 ̇ +‖𝐅𝐒‖ +, 0) +to be the equivalent engineering strain rate in the direction of loading and define +𝜗(𝑒 ̇, 𝑺) = +𝐹𝑋𝑋(𝑒 ̇)|𝑆𝑋𝑋| + 𝐹𝑌𝑌(𝑒 ̇)|𝑆𝑌𝑌| + 2|𝑆𝑋𝑌| +|𝑆𝑋𝑋| + |𝑆𝑌𝑌| + 2|𝑆𝑋𝑌| +, +meaning that the strain rate scale factor defaults to the user input data FXX and FYY for +uniaxial loading in the two material directions, respectively. Note that we only consider +strain rate scaling in loading and not in unloading, and furthermore that the strain rates +used in evaluating the curves are pre-filtered using the time window DT to avoid +excessive numerical noise. To this end, it is recommended to set DT to a time +corresponding to at least hundred time steps or so. +*MAT_PLASTIC_GREEN-NAGHDI_RATE +This is Material Type 35. This model is available only for brick elements and is similar +to model 3, but uses the Green-Naghdi Rate formulation rather than the Jaumann rate +for the stress update. For some cases this might be helpful. This model also has a strain +rate dependency following the Cowper-Symonds model. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +E +F +3 +4 +PR +F +4 +5 +6 +7 +8 +5 +6 +7 +8 +Variable +SIGY +ETAN +SRC +SRP +BETA +Type +F +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +SIGY +ETAN +SRC +SRP +BETA +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Density +Young’s modulus +Poisson’s ratio +Yield stress +Plastic hardening modulus +Strain rate parameter, C +Strain rate parameter, P +Hardening parameter, 0 < β′ < 1 +*MAT_3-PARAMETER_BARLAT_{OPTION} +This is Material Type 36. This model was developed by Barlat and Lian [1989] for +modeling sheets with anisotropic materials under plane stress conditions. This material +allows the use of the Lankford parameters for the definition of the anisotropy. This +particular development is due to Barlat and Lian [1989]. A version of this material +model which has a flow limit diagram failure option is *MAT_FLD_3-PARAME- +TER_BARLAT. +Available options include: + +NLP +The NLP option estimates failure using the Formability Index (F.I.), which accounts for +the non-linear strain paths seen in metal forming applications . The +NLP field in card 3 must be defined when using this option. The NLP option is also +available in *MAT_037, *MAT_125 and *MAT_226. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +Variable +Type +1 +M +F +2 +RO +F +2 +3 +E +F +3 +4 +PR +F +4 +5 +HR +F +5 +R00/AB +R45/CB +R90/HB +LCID +F +F +F +I +6 +P1 +F +6 +E0 +F +7 +P2 +F +7 +SPI +F +8 +ITER +F +8 +P3 +F +Define the following card if and only if M < 0 +Card opt. +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CRC1 +CRA1 +CRC2 +CRA2 +CRC3 +CRA3 +CRC4 +CRA4 +Type +F +F +F +F +F +F +F +1 +Variable +AOPT +Type +F + Card 4 +1 +Variable +Type + Card 5 +Variable +1 +V1 +Type +F +Optional card. +2 +C +F +2 +2 +V2 +F +3 +P +F +3 +3 +V3 +F +*MAT_3-PARAMETER_BARLAT +4 +5 +6 +7 +8 +VLCID +PB +NLP/HTA +HTB +F +I/F +I +4 +A1 +F +4 +D1 +F +F +8 +7 +HTC +HTD +F +7 +F +8 +BETA +HTFLAG +F +F +5 +A2 +F +5 +D2 +F +6 +A3 +F +6 +D3 +F + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +USRFAIL +LCBI +LCSH +Type +F +F +F + VARIABLE +DESCRIPTION +MID +RO +E +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus, 𝐸 +GT.0.0: Constant value, +LT.0.0: Load curve ID = (-E) which defines Young’s Modulus +as a function of plastic strain. See Remarks. +VARIABLE +DESCRIPTION +PR +HR +Poisson’s ratio, ν +Hardening rule: +EQ.1.0: linear (default), +EQ.2.0: exponential (Swift) +EQ.3.0: load curve or table with strain rate effects +EQ.4.0: exponential (Voce) +EQ.5.0: exponential (Gosh) +EQ.6.0: exponential (Hocket-Sherby) +EQ.7.0: load curves in three directions +EQ.8.0: table with temperature dependence +EQ.9.0: 3d table with temperature and strain rate dependence +P1 +Material parameter: +HR.EQ.1.0: Tangent modulus, +HR.EQ.2.0: 𝑘, strength coefficient for Swift exponential hard- +ening +HR.EQ.4.0: 𝑎, coefficient for Voce exponential hardening +HR.EQ.5.0: 𝑘, strength coefficient for Gosh exponential hard- +ening +HR.EQ.6.0: 𝑎, coefficient for Hocket-Sherby exponential hard- +ening +HR.EQ.7.0: load curve ID for hardening in 45 degree direction. +See Remarks. +P2 +Material parameter: +HR.EQ.1.0: Yield stress +HR.EQ.2.0: 𝑛, exponent for Swift exponential hardening +HR.EQ.4.0: 𝑐, coefficient for Voce exponential hardening +HR.EQ.5.0: 𝑛, exponent for Gosh exponential hardening +HR.EQ.6.0: 𝑐, coefficient for Hocket-Sherby exponential hard- +ening +HR.EQ.7.0: load curve ID for hardening in 90 degree direction. +See Remarks. +*MAT_3-PARAMETER_BARLAT +DESCRIPTION +ITER +Iteration flag for speed: +ITER.EQ.0.0: fully iterative +ITER.EQ.1.0: fixed at three iterations +M +CRCn +CRAn +R00 +Generally, ITER = 0 is recommended. However, ITER = 1 is +somewhat faster and may give acceptable results in most +problems. +𝑚, exponent in Barlat’s yield surface, absolute value is used if +negative. +Chaboche-Rousselier hardening parameters, see Remarks. +Chaboche-Rousselier hardening parameters, see Remarks. +𝑅00, Lankford parameter in 0 degree direction +GT.0.0: Constant value, +LT.0.0: Load curve or Table ID = (-R00) which defines 𝑅 value +as a function of plastic strain (Curve) or as a function of +temperature and plastic strain (Table). See Remarks. +R45 +𝑅45, Lankford parameter in 45 degree direction +GT.0.0: Constant value, +LT.0.0: Load curve or Table ID = (-R45) which defines R value +as a function of plastic strain (Curve) or as a function of +temperature and plastic strain (Table). See Remarks. +R90 +𝑅90, Lankford parameter in 90 degree direction +GT.0.0: Constant value, +LT.0.0: Load curve or Table ID = (-R90) which defines R value +as a function of plastic strain (Curve) or as a function of +temperature and plastic strain (Table). See Remarks. +AB +CB +HB +LCID +𝑎, Barlat89 parameter, which is read instead of R00 if PB > 0. +𝑐, Barlat89 parameter, which is read instead of R45 if PB > 0. +ℎ, Barlat89 parameter, which is read instead of R90 if PB > 0. +Load curve/table ID for hardening in the 0 degree direction. See +Remarks. +VARIABLE +DESCRIPTION +E0 +Material parameter +HR.EQ.2.0: 𝜀0 for determining initial yield stress for Swift +exponential hardening. (Default = 0.0) +HR.EQ.4.0: 𝑏, coefficient for Voce exponential hardening +HR.EQ.5.0: 𝜀0 for determining initial yield stress for Gosh +exponential hardening. (Default = 0.0) +HR.EQ.6.0: 𝑏, coefficient for Hocket-Sherby exponential hard- +ening +SPI +Case I: if 𝜀0 is zero above and HR.EQ.2.0. (Default = 0.0) +[1 +⁄ +] +(𝑛−1) +EQ.0.0: 𝜀0 = (𝐸 +𝑘) +LE.0.02: 𝜀0 = SPI +GT.0.02: 𝜀0 = (SPI +𝑘 ) +[1 +𝑛⁄ ] +Case II: If HR.EQ.5.0 +The strain at plastic yield is determined by an iterative procedure +based on the same principles as for HR.EQ.2.0. +P3 +Material parameter: +HR.EQ.5.0: 𝑝, parameter for Gosh exponential hardening +HR.EQ.6.0: 𝑛, +exponent +for Hocket-Sherby +exponential +hardening +AOPT +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the shell ele- +ment normal by an angle BETA. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +C +P +VLCID +PB +NLP +HTA +HTB +*MAT_3-PARAMETER_BARLAT +DESCRIPTION +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available with the R3 release +of Version 971 and later. +𝐶 in Cowper-Symonds strain rate model +𝑝 in Cowper-Symonds strain rate model, 𝑝 = 0.0 for no strain rate +effects +Volume correction curve ID defining the relative volume change +(change in volume relative to the initial volume) as a function of +the effective plastic strain. This is only used when nonzero. See +Remarks. +Barlat89 parameter, p. If PB > 0, parameters AB, CB, and HB are +read instead of R00, R45, and R90. See Remarks below. +ID of a load curve of the Forming Limit Diagram (FLD) under +linear strain paths. In the load curve, abscissas represent minor +strains while ordinates represent major strains. Define only when +option NLP is used. See Remarks. +Load curve/Table ID for postforming parameter A in heat +treatment +Load curve/Table ID for postforming parameter B in heat +treatment +XP, YP, ZP +Coordinates of point 𝐩 for AOPT = 1. +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +HTC +HTD +Load curve/Table ID for postforming parameter C in heat +treatment +Load curve/Table ID for postforming parameter D in heat +treatment +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3. +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2. +VARIABLE +BETA +DESCRIPTION +Material angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA. +HTFLAG +Heat treatment flag : +HTFLAG.EQ.0: Preforming stage +HTFLAG.EQ.1: Heat treatment stage +HTFLAG.EQ.2: Postforming stage +USRFAIL +User defined failure flag +USRFAIL.EQ.0: no user subroutine is called +USRFAIL.EQ.1: user subroutine matusr_24 in dyn21.f is called +HR.EQ.7: Load curve defining biaxial stress vs. biaxial strain +for hardening rule, see discussion in the formulation +section below for a definition. +HR.NE.7: Ignored. +HR.EQ.7: Load curve defining shear stress vs. shear strain for +hardening, see discussion in the formulation section +below for a definition. +HR.NE.7: Ignored. +LCBI +LCSH +Formulation: +The effective plastic strain used in this model is defined to be plastic work equivalent. +A consequence of this is that for parameters defined as functions of effective plastic +strain, the rolling (00) direction should be used as reference direction. For instance, the +hardening curve for HR = 3 is the stress as function of strain for uniaxial tension in the +rolling direction, VLCID curve should give the relative volume change as function of +strain for uniaxial tension in the rolling direction and load curve given by -E should +give the Young’s modulus as function of strain for uniaxial tension in the rolling +direction. Optionally, the curve can be substituted for a table defining hardening as +function of plastic strain rate (HR = 3) or temperature (HR = 8). +Exceptions from the rule above are curves defined as functions of plastic strain in the 45 +and 90 directions, i.e., P1 and P2 for HR = 7 and negative R45 or R90, see Fleischer et.al. +[2007]. The hardening curves are here defined as measured stress as function of +measured plastic strain for uniaxial tension in the direction of interest, i.e., as +determined from experimental testing using a standard procedure. The optional biaxial +and shear hardening curves require some further elaboration, as we assume that a +biaxial or shear test reveals that the true stress tensor in the material system expressed +as +is a function of the (plastic) strain tensor +𝝈 = ( +0 ±𝜎 +) , +𝜎 ≥ 0, +𝜺 = ( +𝜀1 +0 ±𝜀2 +) , +𝜀1 ≥ 0, +𝜀2 ≥ 0, +The input hardening curves are 𝜎 as function of 𝜀1+𝜀2. The ± sign above distinguishes +between the biaxial (+) and the shear (−) cases. Moreover, the curves defining the R +values are as function of the measured plastic strain for uniaxial tension in the direction +of interest. These curves are transformed internally to be used with the effective stress +and strain properties in the actual model. The effective plastic strain does not coincide +with the plastic strain components in other directions than the rolling direction and may +be somewhat confusing to the user. Therefore the von Mises work equivalent plastic +strain is output as history variable #2 if HR = 7 or if any of the R-values is defined as +function of the plastic strain. +The R-values in curves are defined as the ratio of instantaneous width change to +instantaneous thickness change. That is, assume that the width W and thickness T are +measured as function of strain. Then the corresponding R-value is given by: +𝑅 = +𝑑𝑊 +𝑑𝜀 +𝑑𝑇 +𝑑𝜀 +/𝑊 +/𝑇 +The anisotropic yield criterion Φ for plane stress is defined as: +𝑚 +Φ = 𝑎|𝐾1 + 𝐾2|𝑚 + 𝑎|𝐾1 − 𝐾2|𝑚 + 𝑐|2𝐾2|𝑚 = 2𝜎𝑌 +where 𝜎𝑌 is the yield stress and Ki = 1,2 are given by: +𝐾1 = +𝜎𝑥 + ℎ𝜎𝑦 +√ +√√ +⎷ +𝐾2 = +( +𝜎𝑥 − ℎ𝜎𝑦 +) +2 ++ 𝑝2𝜏𝑥𝑦 +If PB = 0, the anisotropic material constants a, c, h, and p are obtained through R00, R45, +and R90: +𝑎 = 2 − 2√( +𝑅00 +1 + 𝑅00 +) ( +𝑅90 +1 + 𝑅90 +) +𝑐 = 2 − 𝑎 +ℎ = √( +𝑅00 +1 + 𝑅00 +) ( +1 + 𝑅90 +𝑅90 +) +The anisotropy parameter p is calculated implicitly. According to Barlat and Lian the R +value, width to thickness strain ratio, for any angle 𝜙 can be calculated from: +𝑅𝜙 = +2𝑚𝜎𝑌 ++ ∂Φ +∂𝜎𝑦 +(∂Φ +∂𝜎𝑥 +) 𝜎𝜙 +− 1 +where 𝜎𝜙 is the uniaxial tension in the 𝜙 direction. This expression can be used to +iteratively calculate the value of p. Let 𝜙 = 45 and define a function 𝑔 as: +𝑔(𝑝) = +2𝑚𝜎𝑌 ++ ∂Φ +∂𝜎𝑦 +(∂Φ +∂𝜎𝑥 +) 𝜎𝜙 +− 1 − 𝑅45 +An iterative search is used to find the value of p. If PB > 0, material parameters a (AB), +c (CB), h (HB), and p (PB) are used directly. +For face centered cubic (FCC) materials m = 8 is recommended and for body centered +cubic (BCC) materials m = 6 may be used. The yield strength of the material can be +expressed in terms of k and n: +𝜎𝑦 = 𝑘𝜀𝑛 = 𝑘(𝜀𝑦𝑝 + 𝜀̅𝑝) +where 𝜀𝑦𝑝 is the elastic strain to yield and 𝜀̅𝑝is the effective plastic strain (logarithmic). +If SIGY is set to zero, the strain to yield if found by solving for the intersection of the +linearly elastic loading equation with the strain hardening equation: +𝜎 = 𝐸𝜀 +𝜎 = 𝑘𝜀𝑛 +which gives the elastic strain at yield as: +If SIGY yield is nonzero and greater than 0.02 then: +𝜀𝑦𝑝 = ( +𝑛−1 +) +𝜀𝑦𝑝 = ( +𝜎𝑦 +) +The other available hardening models include the Voce equation given by: +the Gosh equation given by: +𝜎Y(𝜀𝑝) = 𝑎 − 𝑏𝑒−𝑐𝜀𝑝, +𝜎Y(𝜀𝑝) = 𝑘(𝜀0 + 𝜀𝑝)𝑛 − 𝑝, +and finally the Hocket-Sherby equation given by: +𝜎Y(𝜀𝑝) = 𝑎 − 𝑏𝑒−𝑐𝜀𝑝 +. +For the Gosh hardening law, the interpretation of the variable SPI is the same, i.e., if set +to zero the strain at yield is determined implicitly from the intersection of the strain +hardening equation with the linear elastic equation. +To include strain rate effects in the model we multiply the yield stress by a factor +depending on the effective plastic strain rate. We use the Cowper-Symonds’ model, +hence the yield stress can be written as: +1/𝑝 +𝜀̇𝑝 +1 + ( +𝑠 (𝜀𝑝) +𝜎Y(𝜀𝑝, 𝜀̇𝑝) = 𝜎Y +{⎧ +⎩{⎨ +𝑠 denotes the static yield stress, 𝐶 and 𝑝 are material parameters, 𝜀̇𝑝 is the +where 𝜎Y +effective plastic strain rate. It is also possible to use a table with HR.EQ.3 for defining +the strain rate effects, for which each load curve in the table defines the yield stress as +function of plastic strain for a given strain rate. In contrast to material 24, whenever the +strain rate is higher than that of any curve in the table, the table is extrapolated in the +strain rate direction to find the appropriate yield stress. +}⎫ +⎭}⎬ +) +A kinematic hardening model is implemented following the works of Chaboche and +Roussilier. A back stress α is introduced such that the effective stress is computed as: +𝜎eff = 𝜎eff(𝜎11 − 2𝛼11 − 𝛼22, 𝜎22 − 2𝛼22 − 𝛼11, 𝜎12 − 𝛼12) +The back stress is the sum of up to four terms according to: +𝛼𝑖𝑗 = ∑ 𝛼𝑖𝑗 +𝑘=1 +and the evolution of each back stress component is as follows: +𝛿𝛼𝑖𝑗 +𝑘 = 𝐶𝑘 (𝑎𝑘 +𝑠𝑖𝑗 +𝜎eff +− 𝛼𝑖𝑗 +𝑘 ) 𝛿𝜀𝑝 +where 𝐶𝑘 and 𝑎𝑘 are material parameters,𝑠𝑖𝑗 is the deviatoric stress tensor, 𝜎eff is the +effective stress and 𝜀𝑝 is the effective plastic strain. The yield condition is for this case +modified according to +𝑓 (σ,α, 𝜀𝑝) = 𝜎eff(𝜎11 − 2𝛼11 − 𝛼22, 𝜎22 − 2𝛼22 − 𝛼11, 𝜎12 − 𝛼12) +− {𝜎𝑌 +𝑡 (𝜀𝑝, 𝜀̇𝑝, 0) − ∑ 𝑎𝑘[1 − exp(−𝐶𝑘𝜀𝑝 ] +} ≤ 0 +in order to get the expected stress strain response for uniaxial stress. +The calculated effective stress is stored in history variable #7. +𝑘=1 +A Failure Criterion For Nonlinear Strain Paths (NLP) in sheet metal forming: +When the option NLP is used, a necking failure criterion is activated to account for the +non-linear strain path effect in sheet metal forming. Based on the traditional Forming +Limit Diagram (FLD) for the linear strain path, the Formability Index (F.I.) is calculated +for every element in the model throughout the simulation duration. The entire F.I. time +history for every element is stored in history variable #1 in d3plot files, accessible from +Post/History menu in LS-PrePost v4.0. In addition to the F.I. output, other useful +information stored in other history variables can be found as follows, +1. Formability Index: #1 +2. Strain ratio (in-plane minor strain/major strain): #2 +3. Effective strain from the planar isotropic assumption: #3 +To enable the output of these history variables to the d3plot files, NEIPS on the *DATA- +BASE_EXTENT_BINARY card must be set to at least 3. The history variables can also +be plotted on the formed sheet blank as a color contour map, accessible from +Post/FriComp/Misc menu. The index value starts from 0.0, with the onset of necking +failure when it reaches 1.0. The F.I. is calculated based on critical effect strain method, +as illustrated in a figure in Remarks section in *MAT_037. The theoretical background +can be found in two papers also referenced in Remarks section in *MAT_037. +When d3plot files are used to plot the history variable #1 (the F.I.) in color contour, the +value in the “Max” pull-down menu in Post/FriComp needs to be set to “Min”, meaning +that the necking failure occurs only when all integration points through the thickness +have reached the critical value of 1.0 (refer to Tharrett and Stoughton’s paper in 2003 SAE +2003-01-1157). It is also suggested to set the variable “MAXINT” in *DATABASE_EX- +TENT_BINARY to the same value as the variable “NIP” in *SECTION_SHELL. In +addition, the value in the “Avg” pull-down menu in Post/FriRang needs to be set to +“None”. The strain path history (major vs. minor strain) of each element can be plotted +with the radial dial button Strain Path in Post/FLD. +An example of a partial input for the material is provided below, where the FLD for the +linear strain path is defined by the variable NLP with load curve ID 211, where +abscissas represent minor strains and ordinates represent major strains. +*MAT_3-PARAMETER_BARLAT_NLP +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +$ MID RO E PR HR P1 P2 ITER + 1 2.890E-09 6.900E04 0.330 3.000 +$ M R00 R45 R90 LCID E0 SPI P3 + 8.000 0.800 0.600 0.550 99 +$ AOPT C P VLCID NLP + 2.000 211 +$ A1 A2 A3 + 0.000 1.000 0.000 +$ V1 V2 V3 D1 D2 D3 BETA +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +$ Hardening Curve +*DEFINE_CURVE + 99 + 0.000 130.000 + 0.002 134.400 + 0.006 143.000 + 0.010 151.300 + 0.014 159.300 + ⋮ ⋮ + 0.900 365.000 + 1.000 365.000 +$ FLD Definition +*DEFINE_CURVE +211 + -0.2 0.325 + -0.1054 0.2955 + -0.0513 0.2585 + 0.0000 0.2054 + 0.0488 0.2240 + 0.0953 0.2396 + 0.1398 0.2523 + 0.1823 0.2622 + ⋮ ⋮ +Shown in Figures M36-1, M36-2 and M36-3, predictions and validations of forming limit +curves (FLC) of various nonlinear strain paths on a single shell element was done using +this new option, for an Aluminum alloy with r00 = 0.8, r45 = 0.6, r90 = 0.55, and yield at +130.0 MPa. In each case, the element is further strained in three different paths (uniaxial +stress – U.A., plane strain – P.S., and equi-biaxial strain – E.B.) separately, following a +pre-straining in uniaxial, plane strain and equi-biaxial strain state, respectively. The +forming limits are determined at the end of the secondary straining for each path, when +the F.I. has reached the value of 1.0. It is seen that the predicted FLCs (dashed curves) +in case of the nonlinear strain paths are totally different from the FLCs under the linear +strain paths. It is noted that the current predicted FLCs under nonlinear strain path are +obtained by connecting the ends of the three distinctive strain paths. More detailed +FLCs can be obtained by straining the elements in more paths between U.A. and P.S. +and between P.S. and E.B. In Figure M36-4, time-history plots of F.I., strain ratio and +effective strain are shown for uniaxial pre-strain followed by equi-biaxial strain path on +the same single element. +Typically, to assess sheet formability, F.I. contour of the entire part should be plotted. +Based on the contour plot, non-linear strain path and the F.I. time history of a few +elements in the area of concern can be plotted for further study. These plots are similar +to those shown in manual pages of *MAT_037. +Heat treatment with variable HTFLAG: +Heat treatment for increasing the formability of prestrained aluminum sheets can be +simulated through the use of HTFLAG, where the intention is to run a forming +simulation in steps involving preforming, springback, heat treatment and postforming. +In each step the history is transferred to the next via the use of dynain . The first two steps are performed with HTFLAG = 0 according +0corresponding to the +to standard procedures, resulting in a plastic strain field 𝜀𝑝 +prestrain. The heat treatment step is performed using HTFLAG = 1 in a coupled +thermomechanical simulation, where the blank is heated. The coupling between +thermal and mechanical is only that the maximum temperature 𝑇0 is stored as a history +variable in the material model, this corresponding to the heat treatment temperature. +Here it is important to export all history variables to the dynein file for the postforming +step. In the final postforming step, HTFLAG = 2, the yield stress is then augmented by +the Hocket-Sherby like term: +0) +Δ𝜎 = 𝑏 − (𝑏 − 𝑎)exp[−𝑐(𝜀𝑝 − 𝜀𝑝 +] +where a, b, c and d are given as tables as functions of the heat treatment temperature 𝑇0 +0. That is, in the table definitions each load curve corresponds to a given +and prestrain 𝜀𝑝 +prestrain and the load curve value is with respect to the heat treatment temperature, +𝑎 = 𝑎(𝑇0, 𝜀𝑝 +0) 𝑏 = 𝑏(𝑇0, 𝜀𝑝 +0) 𝑐 = 𝑐(𝑇0, 𝜀𝑝 +0) 𝑑 = 𝑑(𝑇0, 𝜀𝑝 +0) +The effect of heat treatment is that the material strength decreases but hardening +increases, thus typically: +𝑎 ≤ 0 𝑏 ≥ 𝑎 𝑐 > 0 𝑑 > 0 +Revision information: +The option NLP is available in explicit dynamic analysis and in SMP and MPP, starting +in Revision 95576. +Fx 0= +n i- a +x i a l str e s s +Fx 0= +uy +P la n e str ai n +uy +Fx 0= +n i- a +x i a l str e s s +Fx 0= +uy +u i- b ia x ial +uy +ux +uy= +n str a i n +e ll + s h +FLC- nonlinear strain path +FLC- linear strain path +0.35 +0.30 +0.25 +0.20 +0.15 +0.10 +0.05 +U.A. +P.S. +E.B. +U.A. +-0.2 +-0.1 +0.1 +Minor true strain +0.2 +Figure M36-1. Nonlinear FLD prediction with uniaxial pre-straining. +Fx 0= +n i- a +x i a l str e s s +Fx 0= +uy +P la n e str ai n +uy +P la n e str ai n +uy +u i- b ia x ial +uy +ux +uy= +n str a i n +e ll + s h +FLC- nonlinear strain path +FLC- linear strain path +0.35 +0.30 +0.25 +0.20 +0.15 +0.10 +0.05 +U.A. +P.S. +E.B. +P.S. +-0.2 +-0.1 +0.1 +Minor true strain +0.2 + Figure M36-2. Nonlinear FLD prediction with plane strain pre-straining. +Fx 0= +n i- a +x i a l str e s s +Fx 0= +uy +P la n e str ai n +u i- b ia x ial +uy +ux +uy= +uy +u i- b ia x ial +uy +ux +uy= +n str a i n +e ll + s h +FLC- nonlinear strain path +FLC- linear strain path +U.A. +E.B. +P.S. +E.B. +0.35 +0.30 +0.25 +0.20 +0.15 +0.10 +0.05 +-0.2 +-0.1 +0.1 +Minor true strain +0.2 + Figure M36-3. Nonlinear FLD prediction with equi-biaxial pre-straining. +1.2 +1.0 +0.8 +0.6 +0.4 +0.2 +0.0 +1.0 +0.8 +0.6 +0.4 +0.2 +0.0 +-0.2 +-0.4 +0.6 +0.5 +0.4 +0.3 +0.2 +0.1 +0.0 +) +# +( +. +. +) +# +( +) +# +( +Uniaxial +Equi-biaxial +Time, seconds (E-03) +Uniaxial +Equi-biaxial +Time, seconds (E-03) +Uniaxial +Equi-biaxial +Time, seconds (E-03) +Figure M36-4. Time-history plots of the three history variables. +*MAT_EXTENDED_3-PARAMETER_BARLAT +This is Material Type 36E. This model is an extension to the standard 3-parameter +Barlat model and allows for different hardening curves and R-values in different +directions, see Fleischer et.al. [2007]. The directions in this context are the three +uniaxial directions (0, 45 and 90 degrees) and optionally biaxial and shear. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +E +F +3 +4 +PR +F +4 +5 +6 +7 +8 +5 +6 +7 +8 +Variable +LCH00 +LCH45 +LCH90 +LCHBI +LCHSH +Type +F + Card 3 +1 +F +2 +F +3 +F +4 +F +5 +Variable +LCR00 +LCR45 +LCR90 +LCRBI +LCRSH +F +2 +F +3 +Type +F + Card 4 +1 +Variable +AOPT +Type +F + Card 5 +1 +2 +3 +Variable +Type +2-270 (EOS) +F +4 +4 +A1 +F +F +5 +5 +A2 +F +6 +M +F +6 +6 +A3 +F +7 +8 +7 +8 +Card 6 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +BETA +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +LCHXX +LCHBI +LCHSH +LCRXX +LCRBI +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus, 𝐸. +Poisson’s ratio, ν. +Load curve defining uniaxial stress vs. uniaxial strain in the +given direction (XX is either 00, 45, 90). The exact definition is +discussed in the Remarks below. LCH00 must be defined, the +other defaults to LCH00 if not defined. +Load curve defining biaxial stress vs. + biaxial strain, see +discussion in the Remarks below for a definition. If not defined +this is determined from LCH00 and the initial R-values to yield a +response close to the standard 3-parameter Barlat model. +Load curve defining shear stress vs. shear strain, see discussion +in the Remarks below for a definition. If not defined this is +ignored to yield a response close to the standard 3-parameter +Barlat model. +Load curve defining standard R-value vs. uniaxial strain in the +given direction (XX is either 00, 45, 90). The exact definition is +discussed in the Remarks below. Default is a constant R-value of +1.0, a negative input will result in a constant R-value of –LCRXX. +Load curve defining biaxial R-value vs. biaxial strain, see +discussion in the Remarks below for a definition. Default is a +constant R-value of 1.0, a negative input will result in a constant +R-value of –LCRBI. +LCRSH +M +AOPT +*MAT_EXTENDED_3-PARAMETER_BARLAT +DESCRIPTION +Load curve defining shear R-value vs. shear strain, see discussion +in the Remarks below for a definition. Default is a constant R- +value of 1.0, a negative input will result in a constant R-value of – +LCRSH. +Barlat flow exponent, 𝑚, must be an integer value. +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the shell ele- +ment normal by an angle BETA. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available with the R3 release +of Version 971 and later. +XP, YP, ZP +Coordinates of point 𝐩 for AOPT = 1. +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3. +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2. +BETA +Material angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA. +Formulation: +The hardening curves LCH00, LCH45 and LCH90 are here defined as measured stress +as function of measured plastic strain for uniaxial tension in the direction of interest, +i.e., as determined from experimental testing using a standard procedure. The optional +biaxial and shear hardening curves LCHBI and LCHSH require some further +elaboration, as we assume that a biaxial or shear test reveals that the true stress tensor +in the material system expressed as +is a function of the (plastic) strain tensor +𝝈 = ( +0 ±𝜎 +) , +𝜎 ≥ 0, +𝜺 = ( +𝜀1 +0 ±𝜀2 +) , +𝜀1 ≥ 0, +𝜀2 ≥ 0, +The input hardening curves are 𝜎 as function of 𝜀1+𝜀2. The ± sign above distinguishes +between the biaxial (+) and the shear (−) cases. +Moreover, the curves LCR00, LCR45 and LCR90 defining the R values are as function of +the measured plastic strain for uniaxial tension in the direction of interest. The R-values +in themselves are defined as the ratio of instantaneous width change to instantaneous +thickness change. That is, assume that the width W and thickness T are measured as +function of strain. Then the corresponding R-value is given by: +𝑅𝜑 = +𝑑𝑊 +𝑑𝜀 +𝑑𝑇 +𝑑𝜀 +/𝑊 +/𝑇 +. +These curves are transformed internally to be used with the effective stress and strain +properties in the actual model. The effective plastic strain does not coincide with the +plastic strain components in other directions than the rolling direction and may be +somewhat confusing to the user. Therefore the von Mises work equivalent plastic strain +is output as history variable #2. As for hardening, the optional biaxial and shear R- +value curves LCRBI and LCRSH are defined in a special way for which we return to the +local plastic strain tensor 𝜺 as defined above. The biaxial and shear R-values are defined +as +𝑅𝑏/𝑠 = +𝜀̇1 +𝜀̇2 +and again the curves are 𝑅𝑏/𝑠 as function of 𝜀1+𝜀2. Note here that the suffix 𝑏 assumes +loading biaxially and 𝑠 assumes loading in shear, so the R-values to be defined are +always positive. +*MAT_TRANSVERSELY_ANISOTROPIC_ELASTIC_PLASTIC_{OPTION} +This is Material Type 37. This model is for simulating sheet forming processes with +anisotropic material. Only transverse anisotropy can be considered. Optionally an +arbitrary dependency of stress and effective plastic strain can be defined via a load +curve. This plasticity model is fully iterative and is available only for shell elements. +Available options include: + +ECHANGE +NLP_FAILURE +NLP2 +The ECHANGE option allows the change of Young’s Modulus during the simulation: +The NLP_FAILURE option estimates failure using the Formability Index (F.I.) which +accounts for the non-linear strain paths common in metal forming application . The option NLP is also available in *MAT_036, *MAT_125 and *MAT_226. +The NLP_FAULURE option uses effective plastic strain to calculate the onset of +necking, which assumes the necking happens in an instant. Some researchers think it +may happen in a longer duration, which can be addressed by the option NLP2, which +calculates the damage during forming and accumulates it to predict the sheet metal +failure. Compared with NLP_FAILURE, there is no input change required. + Card 1 +1 +Variable +MID +Type +A +2 +RO +F +3 +E +F +4 +PR +F +5 +6 +SIGY +ETAN +F +F +7 +R +F +8 +HLCID +F +Additional card for ECHANGE and/or NLP_FAILURE keyword options. + Card 2. +1 +Variable +IDSCALE +Type +I +2 +EA +F +3 +4 +5 +6 +7 +8 +COE +ICFLD +STRAINLT +F +F +VARIABLE +DESCRIPTION +MID +RO +E +PR +SIGY +ETAN +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +Yield stress. +Plastic hardening modulus. When this value is negative, normal +stresses (either from contact or applied pressure) are considered +and *LOAD_SURFACE_STRESS must be used to capture the +stresses. +The negative local 𝑧-stresses caused by the contact pressure can be +viewed from d3plot files after Revision 97158. This data can be +viewed in LS-PrePost by selecting 𝑧-stress under FCOMP → Stress +and select local under FCOMP in LS-PrePost). Prior to Revision +97158, the negative local 𝑧-stresses are stored in history variable #5, +and can be viewed with menu options FCOMP → Misc → history +var #5 in LS-PrePost. This feature is applicable to both shell +element types 2 and 16. It is found in some cases this inclusion +can improve forming simulation accuracy. +R +Anisotropic parameter, also commonly call r-bar, 𝑟 ̅, in sheet metal +forming literature. Its interpretation is given here. +GT.0: Standard formulation. +LT.0: The anisotropic parameter is set to |R|. When R is set to +a negative value the algorithm is modified for better sta- +bility in sheet thickness or thinning for sheet metal form- +ing involving high strength steels or in cases when the +simulation time is long. This feature is available to both +element formulations 2 and 16. An example using this +feature is provided in Remarks, and shown in Figure +M37-4. +HLCID +Load curve ID expressing effective yield stress as a function of +effective plastic strain in uniaxial tension. +IDSCALE +EA, COE +ICFLD +*MAT_TRANSVERSELY_ANISOTROPIC_ELASTIC_PLASTIC +DESCRIPTION +Load curve ID expressing the scale factor for the Young’s modulus +as a function of effective strain. If the EA and COE fields are +specified, this curve is unnecessary. This field is only used and +should only be specified when the option ECHANGE is active. +Coefficients defining the Young’s modulus with respect to the +effective strain, EA is 𝐸𝐴 and COE is 𝜁 . If IDSCALE is defined, +these two parameters are not necessary. Input only when the +option ECHANGE is used. Also see *MAT_125 for an example to +obtain these two coefficients from a test curve. +ID of a load curve of the Forming Limit Diagram (FLD) under +linear strain paths . In the load curve, abscissas +represent minor strains while ordinates represent major strains. +Define only when the option NLP_FAILURE is active. +STRAINLT +Critical strain value at which strain averaging is activated. Input +only when the option NLP_FAILURE is active. See Remarks. +Formulation: +Consider Cartesian reference axes which are parallel to the three symmetry planes of +anisotropic behavior. Then, the yield function suggested by Hill [1948] can be written +as: +𝐹(𝜎22 − 𝜎33)2 + 𝐺(𝜎33 − 𝜎11)2 + 𝐻(𝜎11 − 𝜎22)2 + 2𝐿𝜎23 +2 + 2𝑀𝜎31 +2 + 2𝑁𝜎12 +2 − 1 = 0 +where 𝜎𝑦1, 𝜎𝑦2, and 𝜎𝑦3, are the tensile yield stresses and 𝜎𝑦12, 𝜎𝑦23, and 𝜎𝑦31 are the +shear yield stresses. The constants F, G H, L, M, and N are related to the yield stress by: +2𝐿 = +2𝑀 = +2𝑁 = +2 +𝜎𝑦23 +2 +𝜎𝑦31 +2 +𝜎𝑦12 +2𝐹 = + 2 + +𝜎𝑦2 + 2 − +𝜎𝑦3 + 2 +𝜎𝑦1 +2𝐺 = + 2 + +𝜎𝑦3 + 2 − +𝜎𝑦1 + 2 +𝜎𝑦2 +2𝐻 = + 2 + +𝜎𝑦1 + 2 − +𝜎𝑦2 + 2 . +𝜎𝑦3 +The isotropic case of von Mises plasticity can be recovered by setting: +and +𝐹 = 𝐺 = 𝐻 = +𝐿 = 𝑀 = 𝑁 = +2 +2𝜎𝑦 +2 +2𝜎𝑦 +For the particular case of transverse anisotropy, where properties do not vary in the x1- +x2 plane, the following relations hold: +2𝐹 = 2𝐺 = +2 +𝜎𝑦3 +2𝐻 = +2 − +𝜎𝑦 +2 +𝜎𝑦3 +𝑁 = +2 − +𝜎𝑦 +2 +𝜎𝑦3 +where it has been assumed that 𝜎𝑦1 = 𝜎𝑦2 = 𝜎𝑦. +Letting 𝐾 = +𝜎𝑦 +𝜎𝑦3 +, the yield criteria can be written as: +𝐹(𝜎) = 𝜎𝑒 = 𝜎𝑦, +where, +𝐹(𝜎) ≡ [𝜎11 +2 + 𝜎22 +2 + 𝐾2𝜎33 +2 − 𝐾2𝜎33(𝜎11 + 𝜎22) − (2 − 𝐾2)𝜎11𝜎22 + 2𝐿𝜎𝑦 +2(𝜎23 +2 ) +2 + 𝜎31 ++ 2 (2 − +2 ] +𝐾2) 𝜎12 +2⁄ +. +The rate of plastic strain is assumed to be normal to the yield surface so 𝜀̇𝑖𝑗 +from: +𝑝 is found +𝑝 = 𝜆 +𝜀̇𝑖𝑗 +∂𝐹 +∂𝜎𝑖𝑗 +. +Now consider the case of plane stress, where σ33 = 0. Also, define the anisotropy input +parameter, R, as the ratio of the in-plane plastic strain rate to the out-of-plane plastic +strain rate, +𝑅 = +𝜀̇22 +𝑝 . +𝜀̇33 +It then follows that +𝑅 = +𝐾2 − 1. +Using the plane stress assumption and the definition of R, the yield function may now +be written as: +𝐹(𝜎) = [𝜎11 +2 + 𝜎22 +2 − +2𝑅 +𝑅 + 1 +𝜎11𝜎22 + 2 +2𝑅 + 1 +𝑅 + 1 +2⁄ +. +2 ] +𝜎12 +Discussion and ECHANGE: +It is noted that there are several differences between this model and other plasticity +models for shell elements such as the model, MAT_PIECEWISE_LINEAR_PLASTICI- +TY. First, the yield function for plane stress does not include the transverse shear stress +components which are updated elastically, and, secondly, this model is always fully +iterative. Consequently, in comparing results for the isotropic case where R = 1.0 with +other isotropic model, differences in the results are expected, even though they are +usually insignificant. +The Young’s modulus has been assumed to be constant. Recently, some researchers +have found that Young’s modulus decreases with respect to the increase of effective +strain. To accommodate this new observation, a new option of ECHANGE is added. +There are two methods defining the change of Young’s modulus change: +The first method is to use a curve to define the scale factor with respect to the effective +strain. The value of this scale factor should decrease from 1 to 0 with the increase of +effective strain. +The second method is to use a function as proposed by Yoshida [2003]: +𝐸 = 𝐸0 − (𝐸0 − 𝐸𝐴)[1 − exp(−𝜁 𝜀)]. +An example of the option ECHANGE is provided in the Remarks section of the *MAT_- +125 manual pages. +A Failure Criterion for Nonlinear Strain Paths (NLP): +Background and Definition. +When the option NLP_FAILURE is used, a necking failure criterion independent of +strain path changes is activated. In sheet metal forming, as strain path history (plotted +on in-plane major and minor strain space) of an element becomes non-linear, the +position and shape of a traditional strain-based Forming Limit Diagram (FLD) changes. +This option provides a simple formability index (F.I.) which remains invariant +regardless of the presence of the non-linear strain paths in the model, and can be used +to identify if the element has reached its necking limit. +0.4 +0.3 +0.2 +0.1 +-0.5 +F.I. = Y / YL +YL +0.1 +1.0 +β = dε2 / dε1 + Figure M37-1. Calculation of F.I. based on critical effective strain method. +Formability index (F.I) is calculated, as illustrated in Figure M37-1, for every element in +the sheet blank throughout the simulation duration. The value of F.I. is 0.0 for virgin +material and reaches maximum of 1.0 when the material fails. The theoretical +background can be found in two papers: 1) T.B. Stoughton, X. Zhu, “Review of +Theoretical Models of the Strain-Based FLD and their Relevance to the Stress-Based FLD, +International Journal of Plasticity”, V. 20, Issues 8-9, P. 1463-1486, 2003; and 2) Danielle +Zeng, Xinhai Zhu, Laurent B. Chappuis, Z. Cedric Xia, “A Path Independent Forming +Limited Criterion for Sheet Metal Forming Simulations”, 2008 SAE Proceedings, Detroit MI, +April, 2008. +Required inputs. +The load curve input for ICFLD follows keyword format in *DEFINE_CURVE, with +abscissas as minor strains and ordinates as major strains. +ICFLD can also be specified using the *DEFINE_CURVE_FLC keyword where the sheet +metal thickness and strain hardening value are used. Detailed usage information can be +found in the manual entry for *DEFINE_CURVE_FLC. +The formability index is output as a history variable #1 in d3plot files. In addition to the +F.I. values, starting in Revision 95599, the strain ratio 𝛽 and effective plastic strain 𝜀̅ are +written to the d3plot database as history variables #2 and #3, respectively provided +NEIPS on the second field of the first card of *DATABASE_EXTENT_BINARY is set to +at least 3. The contour map of history variables can be plotted in LS-PrePost, accessible +in Post/FriComp, under Misc, and by Element, under Post/History. +Post-processing information. +When plotting the formability index contour map, first select the history var #1 from +Misc in the FriComp menu. The pull-down menu under FriComp can be used to select +the minimum value “Min” for necking failure detection (refer to Tharrett and Stoughton’s +paper in 2003 SAE 2003-01-1157). In the FriRang dialog, select None on the pull-down +menu next to “Avg”. Lastly, set the simulation result to the last state on the animation +tool bar. The index value ranges from 0.0 to 1.5. The non-linear forming limit is reached +at 1.0. +In addition, the evolution of the index throughout the simulation can be plotted in LS- +PrePost4.0 under Post/History by Element. Select the last entry, which is history var#1 it +may be hidden by a scroll bar. Furthermore, the strain path of an element can be +plotted in Post/FLD, using the Tracer option, by selecting the corresponding integration +point representing the “Min” index value in the Position pull-down menu. +Similarly contour maps and the evolution of the strain ratio and the effective plastic +strain can be plotted in the same way using variables 2 and 3. +By setting the STRAINLT field strains (and strain ratios) can be averaged to reduce +noise, which, in turn, affect the calculation of the formability index. The strain +STRAINLT causes the formability index calculation to use only time averaged strains. +Reasonable STRAINLT values range from 5 × 10−3 to 10−2. +It is suggested that variable “MAXINT” in *DATABASE_EXTENT_BINARY be set to +the same value of as the “NIP” field for the *SECTION_SHELL keyword. +Input example. +An example of a partial keyword input using this non-linear strain path failure criterion +is provided below: +*KEYWORD +... +*DATABASE_EXTENT_BINARY +$ NEIPH NEIPS MAXINT STRFLG SIGFLG EPSFLG RLTFLG ENGFLG + 3 &nip 1 +$ CMPFLG IEVERP BEAMIP DCOMP SHGE STSSZ + 1 2 +... +*MAT_TRANSVERSELY_ANISOTROPIC_ELASTIC_PLASTIC_NLP_FAILURE +$ MID RO E PR SIGY ETAN R HLCID + 1 7.830E-09 2.070E+05 0.28 0.0 0.0 0.864 200 +$ IDY EA COE ICFLD STRAINLT + 891 1.0E-02 +*DEFINE_CURVE +891 +$ minor, major strains for FLD definition + -3.375000e-01 4.965000e-01 + -2.750000e-01 4.340000e-01 + -2.250000e-01 3.840000e-01 + -1.840909e-01 3.430909e-01 + -1.500000e-01 3.090000e-01 + -1.211539e-01 2.801539e-01 + -9.642858e-02 2.554286e-01 + -7.500000e-02 2.340000e-01 + -5.625001e-02 2.152500e-01 + -3.970589e-02 1.987059e-01 + -2.500000e-02 1.840000e-01 +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ load curve 200: Mat_037 property, DP600 NUMISHEET'05 Xmbr, Power law fit +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +*DEFINE_CURVE +200 +0.000,395.000 +0.001,425.200 +0.003,440.300 +0.004,452.000 +0.005,462.400 +0.006,472.100 +As shown in Figure M37-2, F.I contours can be plotted using FriComp/Misc, in LS- +PrePost4.0. Strain paths of individual elements, or elements in an area can be plotted +(Figure M37-3 left) using the “Tracer” feature in the FLD menu. Finally, time history +plot of the formability index for elements selected can be plotted in History menu, +Figure M37-3 right. +Thickness/Thinning Stabilization for Shell Types 2 and 16: +When the 𝑅 value is set to a negative value, it stabilizes the sheet thickness or thinning +in sheet metal forming for some high strength types of steel or in cases where the +simulation time is long. In Figure M37-4, a comparison of thinning contours is shown +on a U-channel forming (one-half model) using negative and positive R values. +Maximum thinning on the draw wall is slight higher in the negative R case than that in +the positive R case. +Revision information: +1)The NLP_FAILURE option is implemented in explicit dynamic and is available +starting in Revision 60925. +2)The maximum F.I. value is change from 1.0 to 1.5 starting in Revision 72219. +3)The NLP_FAILURE option is also available starting in Revision 73241 for implicit +static calculation. +4)History variables #2 and #3 output is available starting in Revision 95599. +in d3plot +5)Local +*LOAD_SURFACE_STRESS) is available starting in Revision 97158. +stress output +(when used +files +𝑧 +together with +6)Negative 𝐸 option (contact pressure/normal stress) activated in formability index +starts in Revision 97296. +7)Numerical material model +type with +the NLP_FAILURE +option +(*MAT_037_NLP_FAULURE) is available starting in Revision 106898. +8)Revision 111547: option NLP2. +Time = 0.1587, #nodes=476931 +Contours of History Variable#1 +min. ipt. value +min=0, at elem# 305 +max=1, at elem# 8887 +Formability +Index +1.0 +0.9 +0.8 +0.7 +0.6 +0.5 +0.4 +0.3 +0.2 +0.1 +Figure M37-2. F.I. contour plot (min IP value, non-averaged). +0.60 +0.50 +0.40 +0.30 +0.20 +0.10 +-0.2 +-0.1 +0.1 +Minor true strain +1.0 +0.8 +0.6 +0.4 +0.2 +. +# +, +# +0.05 +0.1 +0.15 +Time (sec.) +Nonlinear strain paths of a few elements in the box +F.I. time history plots of the elements +Figure M37-3. Strain paths and F.I. history plot for elements in the black +square box of the previous Figure. +Time=0.010271, #nodes=4594, #elem=4349 +Contours of % Thickness Reduction based on current z-strain +min=0.0093799, at elem#42249 +max=22.1816, at elem#39875 +Time=0.010271, #nodes=4594, #elem=4349 +Contours of % Thickness Reduction based on current z-strain +min=0.0597092, at elem#39814 +max=21.2252, at elem#40457 +Thinning % +20 +18 +16 +14 +12 +10 +With negative R-value +With positive R-value +Figure M37-4. Thinning contour comparison. +*MAT_BLATZ-KO_FOAM +*MAT_BLATZ-KO_FOAM +*MAT_038 +This is Material Type 38. This model is for the definition of rubber like foams of +polyurethane. It is a simple one-parameter model with a fixed Poisson’s ratio of .25. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +G +F +4 +REF +F +5 +6 +7 +8 + VARIABLE +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Shear modulus. +Use reference geometry to initialize the stress tensor. The +reference geometry is defined by the keyword:*INITIAL_FOAM_- +REFERENCE_GEOMETRY . +EQ.0.0: off, +EQ.1.0: on. +MID +RO +G +REF +Remarks: +The strain energy functional for the compressible foam model is given by +𝑊 = +( +II +III ++ 2√III − 5) +Blatz and Ko [1962] suggested this form for a 47 percent volume polyurethane foam +rubber with a Poisson’s ratio of 0.25. In terms of the strain invariants, I, II, and III, the +second Piola-Kirchhoff stresses are given as +𝑆𝑖𝑗 = 𝐺 [(𝐼𝛿𝑖𝑗 − 𝐶𝑖𝑗) +III ++ (√III − +II +III +) 𝐶𝑖𝑗 +−1] +where Cij is the right Cauchy-Green strain tensor. This stress measure is transformed to +the Cauchy stress, σij, according to the relationship +𝜎 𝑖𝑗 = III +−1 +2⁄ 𝐹𝑖𝑘𝐹𝑗𝑙𝑆𝑙𝑘 +where Fij is the deformation gradient tensor. +*MAT_FLD_TRANSVERSELY_ANISOTROPIC +This is Material Type 39. This model is for simulating sheet forming processes with +anisotropic material. Only transverse anisotropy can be considered. Optionally, an +arbitrary dependency of stress and effective plastic strain can be defined via a load +curve. A Forming Limit Diagram (FLD) can be defined using a curve and is used to +compute the maximum strain ratio which can be plotted in LS-PrePost. This plasticity +model is fully iterative and is available only for shell elements. Also see the notes +below. +2 +RO +F +2 +3 +E +F +3 +4 +PR +F +4 +5 +6 +SIGY +ETAN +F +5 +F +6 +7 +R +F +7 +8 +HLCID +F +8 + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +Variable +LCFLD +Type +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +SIGY +ETAN +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +Yield stress. +Plastic hardening modulus, see notes for model 37. +R +Anisotropic hardening parameter, see notes for model 37. +HLCID +Load curve ID defining effective stress versus effective plastic +strain. The yield stress and hardening modulus are ignored with +this option. +mjr = 0 +mjr +Plane Strain +80 +70 +60 +50 +40 +30 +20 +10 +mnr +mjr +mnr +Draw +mjr +Stretch +% +-50 +-40 +-30 +-20 +-10 +10 +20 +30 +40 +50 +% Minor Strain +Figure M39-1. Forming limit diagram. +DESCRIPTION +Load curve ID defining the Forming Limit Diagram. Minor +strains in percent are defined as abscissa values and Major strains +in percent are defined as ordinate values. The forming limit +diagram is shown in Figure M39-1. In defining the curve list +pairs of minor and major strains starting with the left most point +and ending with the right most point, see *DEFINE_CURVE. + VARIABLE +LCFLD +Remarks: +See material model 37 for the theoretical basis. The first history variable is the +maximum strain ratio: +𝜀majorworkpiece +𝜀majorfld +. +corresponding to 𝜀minorworkpiece. +*MAT_NONLINEAR_ORTHOTROPIC +This is Material Type 40. This model allows the definition of an orthotropic nonlinear +elastic material based on a finite strain formulation with the initial geometry as the +reference. Failure is optional with two failure criteria available. Optionally, stiffness +proportional damping can be defined. In the stress initialization phase, temperatures +can be varied to impose the initial stresses. This model is only available for shell and +solid elements. +WARNING: We do not recommend using this model at this +time since it can be unstable especially if the +stress-strain curves increase in stiffness with in- +creasing strain. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +EA +F +4 +EB +F +5 +EC +F +6 +7 +8 +PRBA +PRCA +PRCB +F +F +F +Default +none +none +none +none +none +none +none +none + Card 2 +1 +2 +3 +Variable +GAB +GBC +GCA +Type +F +F +F +Default +none +none +none +4 +DT +F +0 +5 +6 +7 +8 +TRAMP +ALPHA +F +0 +F +Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCIDA +LCIDB +EFAIL +DTFAIL +CDAMP +AOPT +MACF +Type +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 4 +Variable +1 +XP +Type +F + Card 5 +Variable +1 +V1 +Type +F +2 +YP +F +2 +V2 +F +3 +ZP +F +3 +V3 +F +4 +A1 +F +4 +D1 +F +5 +A2 +F +5 +D2 +F +6 +A3 +F +6 +D3 +F +I +0 +7 +8 +7 +8 +BETA +F +Optional Card 6 (Applies to Solid elements only) + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCIDC +LCIDAB +LCIDBC +LCIDCA +Type +F +F +F +F +Default optional optional optional optional + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +VARIABLE +DESCRIPTION +EA +EB +EC +PRBA +PRCA +PRCB +GAB +GBC +GCA +DT +𝐸𝑎, Young’s modulus in 𝑎-direction. +𝐸𝑏, Young’s modulus in 𝑏-direction. +𝐸𝑐, Young’s modulus in 𝑐-direction. +𝜈𝑏𝑎, Poisson’s ratio 𝑏𝑎. +𝜈𝑏𝑎, Poisson’s ratio 𝑐𝑎. +𝜈𝑐𝑏, Poisson’s ratio 𝑐𝑏. +𝐺𝑎𝑏, shear modulus 𝑎𝑏. +𝐺𝑏𝑐, shear modulus 𝑏𝑐. +𝐺𝑐𝑎, shear modulus 𝑐𝑎. +Temperature increment for isotropic stress initialization. This +option can be used during dynamic relaxation. +TRAMP +Time to ramp up to the final temperature. +ALPHA +Thermal expansion coefficient. +LCIDA +LCIDB +Optional load curve ID defining the nominal stress versus strain +along 𝑎-axis. Strain is defined as 𝜆𝑎 − 1 where 𝜆𝑎 is the stretch +ratio along the 𝑎-axis. +Optional load curve ID defining the nominal stress versus strain +along 𝑏-axis. Strain is defined as 𝜆𝑏 − 1 where 𝜆𝑏 is the stretch +ratio along the 𝑏-axis. +EFAIL +Failure strain, 𝜆 − 1. +DTFAIL +Time step for automatic element erosion +CDAMP +Damping coefficient. +AOPT +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then, for shells only, rotated about +the shell element normal by an angle BETA. +*MAT_NONLINEAR_ORTHOTROPIC +DESCRIPTION +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the 𝑎-direction. This option is for solid +elements only. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. The plane of a solid element is the +midsurface between the inner surface and outer surface +defined by the first four nodes and the last four nodes +of the connectivity of the element, respectively. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector 𝐯, and +an originating point, 𝐩, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +MACF +Material axes change flag: +EQ.1: No change, default, +EQ.2: switch material axes 𝑎 and 𝑏, +EQ.3: switch material axes 𝑎 and 𝑐, +EQ.4: switch material axes 𝑏 and 𝑐. +XP, YP, ZP +Define coordinates of point 𝐩 for AOPT = 1 and 4. +A1, A2, A3 +(𝑎1, 𝑎2, 𝑎3) define components of vector 𝐚 for AOPT = 2. +D1, D2, D3 +(𝑑1, 𝑑2, 𝑑3) define components of vector 𝐝 for AOPT = 2. +V1, V2, V3 +(𝑣1, 𝑣2, 𝑣3) define components of vector 𝐯 for AOPT = 3 and 4. +VARIABLE +BETA +DESCRIPTION +Material angle in degrees for AOPT = 0 (shells only) and +AOPT = 3. BETA may be overridden on the element card, see +*ELEMENT_SHELL_BETA and *ELEMENT_SOLID_ORTHO.. +The following input is optional and applies to SOLID ELEMENTS only +LCIDC +LCIDAB +LCIDBC +LCIDCA +Load curve ID defining the nominal stress versus strain along 𝑐- +axis. Strain is defined as 𝜆𝑐 − 1 where 𝜆𝑐 is the stretch ratio along +the 𝑐-axis. +Load curve ID defining the nominal ab shear stress versus 𝑎𝑏- +strain in the 𝑎𝑏-plane. Strain is defined as the sin(𝛾𝑎𝑏) where 𝛾𝑎𝑏 +is the shear angle. +Load curve ID defining the nominal ab shear stress versus 𝑎𝑏- +strain in the 𝑏𝑐-plane. Strain is defined as the sin(𝛾𝑏𝑐)where 𝛾𝑏𝑐 is +the shear angle. +Load curve ID defining the nominal ab shear stress versus 𝑎𝑏- +strain in the 𝑐𝑎-plane. Strain is defined as the sin(𝛾𝑐𝑎) where 𝛾𝑐𝑎 is +the shear angle. +*MAT_USER_DEFINED_MATERIAL_MODELS +These are Material Types 41 - 50. The user must provide a material subroutine. See also +Appendix A. This keyword input is used to define material properties for the +subroutine. Isotopic, anisotropic, thermal, and hyperelastic material models with +failure can be handled. + Card 1 +1 +2 +3 +4 +5 +6 +7 +Variable +MID +RO +MT +LMC +NHV +IORTHO/ +ISPOT +IBULK +Type +A8 + Card 2 +1 +F +2 +I +3 +I +4 +I +5 +I +6 +Variable +IVECT +IFAIL +ITHERM +IHYPER +IEOS +LMCA +Type +I +I +I +I +I +I +Additional card for IORTHO = 1. + Card 3 +1 +2 +Variable +AOPT +MACF +Type +F +I + Card 4 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +XP +F +3 +V3 +F +4 +YP +F +4 +D1 +F +5 +ZP +F +5 +D2 +F +6 +A1 +F +6 +D3 +F +I +7 +7 +A2 +F +7 +8 +IG +I +8 +8 +A3 +F +8 +BETA +IEVTS +F +Define LMC material parameters using 8 parameters per card. +Card +Variable +1 +P1 +Type +F +2 +P2 +F +3 +P3 +F +4 +P4 +F +5 +P5 +F +6 +P6 +F +Define LMCA material parameters using 8 parameters per card. +Card +Variable +1 +P1 +Type +F +2 +P2 +F +3 +P3 +F +4 +P4 +F +5 +P5 +F +6 +P6 +F +7 +P7 +F +7 +P7 +F +8 +P8 +F +8 +P8 +F + VARIABLE +DESCRIPTION +MID +RO +MT +LMC +NHV +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +User material type (41 - 50 inclusive). A number between 41 and +50 has to be chosen. If MT < 0, subroutine rwumat in dyn21.f is +called, where the material parameter reading can be modified. +WARNING: If two or more materials in an input +deck share the same MT value, those materials also +share values of other variables on Cards 1 and 2 +excluding MID and RO. Those shared values are +taken from the first material where the common MT +is encountered. +Length of material constant array which is equal to the number of +material constants to be input. +Number of history variables to be stored, see Appendix A. When +the model is to be used with an equation of state, NHV must be +increased by 4 to allocate the storage required by the equation of +state. +VARIABLE +IORTHO/ +ISPOT +DESCRIPTION +EQ.1: if the material is orthotropic. +EQ.2: if material is used with spot weld thinning. +EQ.3: if material is orthotropic and used with spot weld +thinning +IBULK +IG +IVECT +Address of bulk modulus in material constants array, see +Appendix A. +Address of shear modulus in material constants array, see +Appendix A. +Vectorization flag (on = 1). A vectorized user subroutine must be +supplied. +IFAIL +Failure flag. +EQ.0: No failure, +EQ.1: Allows failure of shell and solid elements, +LT.0: |IFAIL| is the address of NUMINT in the material +constants array. NUMINT is defined as the number of +failed integration points that will trigger element dele- +tion. This option applies only to shell and solid elements +(release 5 of version 971). +ITHERM +Temperature flag (on = 1). Compute element temperature. +IHYPER +Deformation gradient flag (on = 1 or –1, or 3). Compute defor- +mation gradient, see Appendix A. +IEOS +Equation of state (on = 1). +LMCA +Length of additional material constant array. +AOPT +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then, for shells only, rotated about +the shell element normal by an angle BETA. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the 𝑎-direction. This option is for solid +VARIABLE +DESCRIPTION +elements only. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector 𝐯 with the +element normal. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector 𝐯, and +an originating point, 𝐩, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM +*DEFINE_ +COORDINATE_VECTOR). Available in R3 version of +971 and later. +or +MACF +Material axes change flag for brick elements for quick changes: +EQ.1: No change, default, +EQ.2: switch material axes 𝑎 and 𝑏, +EQ.3: switch material axes 𝑎 and 𝑐, +EQ.4: switch material axes 𝑏 and 𝑐. +XP, YP, ZP +Coordinates of point 𝐩 for AOPT = 1 and 4. +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3 and 4. +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2. +BETA +IEVTS +Material angle in degrees for AOPT = 0 (shells only) and +AOPT = 3. BETA may be overridden on the element card, see +*ELEMENT_SHELL_BETA and *ELEMENT_SOLID_ORTHO. +Address of 𝐸𝑎 for orthotropic material in thick shell formulation 5 +. +P1 +First material parameter. +VARIABLE +DESCRIPTION +P2 +P3 +P4 +⋮ +Second material parameter. +Third material parameter. +Fourth material parameter. +⋮ +PLMC +LMCth material parameter. +Remarks: +1. Cohesive Elements. Material models for the cohesive element (solid element +type 19) uses the first two material parameters to set flags in the element formula- +tion. +a) P1. The P1 field controls how the density is used to calculate the mass +when determining the tractions at mid-surface (tractions are calculated on +a surface midway between the surfaces defined by nodes 1-2-3-4 and 5-6- +7-8). If P1 is set to 1.0, then the density is per unit area of the midsurface +instead of per unit volume. Note that the cohesive element formulation +permits the element to have zero or negative volume. +b) P2. The second parameter, P2, specifies the number of integration points +(one to four) that are required to fail for the element to fail. If it is zero, +the element will not fail regardless of IFAIL. The recommended value for +P2 is 1. +c) Other Parameters. The cohesive element only uses MID, RO, MT, LMC, +NHV, IFAIL and IVECT in addition to the material parameters. +d) Appendix R. See Appendix R for the specifics of the umat subroutine re- +quirements for the cohesive element. +2. Material Constants. If IORTHO = 0, LMC must be ≤ 48. If IORTHO = 1, LMC +must be ≤ 40. If more material constants are needed, LMCA may be used to +create an additional material constant array. There is no limit on the size of +LMCA. +3. Spot weld thinning. If the user-defined material is used for beam or brick +element spot welds that are tied to shell elements, and SPOTHIN > 0 on *CON- +TROL_CONTACT, then spot weld thinning will be done for those shells if IS- +POT = 2. Otherwise, it will not be done. +4. Thick Shell Formulation 5. IEVTS is optional and is used only by thick shell +formulation 5. It points to the position of 𝐸𝑎 in the material constants array. +Following 𝐸𝑎, the next 5 material constants must be 𝐸𝑏, 𝐸𝑐, 𝜈𝑏𝑎, 𝜈𝑐𝑎, and 𝜈𝑐𝑏. This +data enables thick shell formulation 5 to calculate an accurate thickness strain, +otherwise the thickness strain will be based on the elastic constants pointed to +by IBULK and IG. +*MAT_BAMMAN +This is Material Type 51. It allows the modeling of temperature and rate dependent +plasticity with a fairly complex model that has many input parameters [Bamman 1989]. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F + Card 2 +Variable +1 +C1 +Type +F + Card 3 +Variable +1 +C9 +Type +F + Card 4 +1 +2 +C2 +F +2 +F +2 +Variable +C17 +C18 +Type +F +F +3 +E +F +3 +C3 +F +3 +4 +PR +F +4 +C4 +F +4 +5 +T +F +5 +C5 +F +5 +6 +HC +F +6 +C6 +F +6 +7 +8 +7 +C7 +F +7 +8 +C8 +F +8 +C10 +C11 +C12 +C13 +C14 +C15 +C16 +F +F +F +F +F +3 +A1 +F +4 +A2 +F +5 +A4 +F +6 +A5 +F +7 +A6 +F +F +8 +KAPPA +F + VARIABLE +DESCRIPTION +MID +RO +E +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus (psi) +VARIABLE +DESCRIPTION +PR +T +HC +C1 +C2 +C3 +C4 +C5 +C6 +C7 +C8 +C9 +C10 +C11 +C12 +C13 +C14 +C15 +C16 +C17 +C18 +A1 +A2 +Poisson’s ratio +Initial temperature (°R, degrees Rankine) +Heat generation coefficient (°R⁄psi) +Psi +°R +Psi +°R +1/s +°R +1/psi +°R +Psi +°R +1/psi-s +°R +1/psi +°R +psi +°R +1/psi-s +°R +α1, initial value of internal state variable 1 +α2, initial value of internal state variable 2. Note: α3 = -(α1 + α2 ) +VARIABLE +A3 +A4 +A5 +DESCRIPTION +α4, initial value of internal state variable 3 +α5, initial value of internal state variable 4 +α6, initial value of internal state variable 5 +KAPPA +κ, initial value of internal state variable 6 +Unit Conversion Table +Sec × psi × oR +C1 +C2 +C3 +C4 +C5 +C6 +C7 +C8 +C9 +C10 +C11 +C12 +C13 +C14 +C15 +C16 +C17 +C18 +C0 = HC +E + +T +sec × MPa × oR +× 1⁄145 + — +× 1⁄145 + — + — + — +× 145 + — +× 1⁄145 + — +× 145 + — +× 145 + — +× 1⁄145 + — +× 145 + — +× 145 +× 1⁄145 +— + — +sec × MPA × oK +× 1⁄145 +× 5⁄9 +× 1⁄145 +× 5⁄9 + — +× 5/9 +× 145 +× 5⁄9 +× 1⁄145 +× 5⁄9 +× 145 +× 5⁄9 +× 145 +× 5⁄9 +× 1⁄145 +× 5⁄9 +× 145 +× 5⁄9 +× (145)(5⁄9) +× 1⁄145 + — +× 5⁄9 +*MAT_051 +The kinematics associated with the model are discussed in references [Hill 1948, +Bammann and Aifantis 1987, Bammann 1989]. The description below is taken nearly +verbatim from Bammann [1989]. +With the assumption of linear elasticity we can write, +where the Cauchy stress σ is convected with the elastic spin 𝑾 𝑒 as, += 𝜆 tr(𝑫𝑒)𝟏 + 2𝜇𝑫𝑒 += 𝝈̇ − 𝑾 𝑒𝝈 + 𝝈𝑾 𝑒 +This is equivalent to writing the constitutive model with respect to a set of directors +whose direction is defined by the plastic deformation [Bammann and Aifantis 1987, +Bammann and Johnson 1987]. Decomposing both the skew symmetric and symmetric +parts of the velocity gradient into elastic and plastic parts we write for the elastic +stretching 𝑫𝑒 and the elastic spin 𝑾 𝑒, +𝑫𝑒 = 𝑫 − 𝑫𝑝 − 𝑫𝑡ℎ, 𝑾 𝑒 = 𝑾 = 𝑾 𝑝. +Within this structure it is now necessary to prescribe an equation for the plastic spin 𝑾 𝑝 +in addition to the normally prescribed flow rule for 𝑫𝑝 and the stretching due to the +thermal expansion 𝐷𝑡ℎ. As proposed, we assume a flow rule of the form, +𝑫𝑝 = 𝑓 (𝑇)sinh [ +|𝜉 | − 𝜅 − 𝑌(𝑇) +𝑉(𝑇) +] +𝝃′ +∣𝜉′∣ +. +where T is the temperature, κ is the scalar hardening variable, and ξ′ is the difference +between the deviatoric Cauchy stress σ′ and the tensor variable α′, +𝝃′ = 𝝈′ − 𝜶′ +and f(T), Y(T), V(T) are scalar functions whose specific dependence upon the +temperature is given below. Assuming isotropic thermal expansion and introducing +the expansion coefficient Ȧ , the thermal stretching can be written, +𝑫𝑡ℎ = 𝐴̇𝑇̇𝟏 +The evolution of the internal variables α and κ are prescribed in a hardening minus +recovery format as, +⋅ += ℎ(𝑇)𝑫𝑝 − [𝑟𝑑(𝑇)|𝑫𝑝| + 𝑟𝑠(𝑇)]|𝜶|𝜶, += 𝐻(𝑇)𝑫𝑝 − [𝑅𝑑(𝑇)|𝑫𝑝| + 𝑅𝑠(𝑇)]𝜿2 +where h and H are the hardening moduli, rs(T) and Rs(T) are scalar functions describing +the diffusion controlled ‘static’ or ‘thermal’ recovery, and rd(T) and Rd(T) are the +functions describing dynamic recovery. +If we assume that Wp = 0, we recover the Jaumann stress rate which results in the +prediction of an oscillatory shear stress response in simple shear when coupled with a +Prager kinematic hardening assumption [Johnson and Bammann 1984]. Alternatively +we can choose, +𝑾 𝑝 = 𝑹𝑇𝑼̇ 𝑼 −1𝑹, +which recovers the Green-Naghdi rate of Cauchy stress and has been shown to be +equivalent to Mandel’s isoclinic state [Bammann and Aifantis 1987]. The model +employing this rate allows a reasonable prediction of directional softening for some +materials, but in general under-predicts the softening and does not accurately predict +the axial stresses which occur in the torsion of the thin walled tube. +The final equation necessary to complete our description of high strain rate deformation +is one which allows us to compute the temperature change during the deformation. In +the absence of a coupled thermo-mechanical finite element code we assume adiabatic +temperature change and follow the empirical assumption that 90 -95% of the plastic +work is dissipated as heat. Hence, +𝑇̇ = +. 9 +𝜌𝐶𝑣 +(𝝈 ⋅ 𝑫𝑝), +where ρ is the density of the material and Cv the specific heat. +In terms of the input parameters the functions defined above become: + V(T) = C1 exp(-C2/T) +h(T) = C9 exp(C10/T) + Y(T) = C3 exp(C4/T) +rs(T) = C11exp(-C12/T) +f(T) = C5 exp(-C6/T) + RD(T) = C13exp(-C14/T) +rd(T) = C7 exp(-C8/T) + H(T) = C15exp(C16/T) + RS(T) = C17exp(-C18/T) +and the heat generation coefficient is +𝐻𝐶 = +0.9 +𝜌𝐶𝑣 +. +*MAT_052 +This is Material Type 52. This is an extension of model 51 which includes the modeling +of damage. See Bamman et al. [1990]. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F + Card 2 +Variable +1 +C1 +Type +F + Card 3 +Variable +1 +C9 +Type +F + Card 4 +1 +2 +C2 +F +2 +F +2 +Variable +C17 +C18 +Type +F +F + Card 5 +Variable +Type +1 +N +F +2 +D0 +F +3 +E +F +3 +C3 +F +3 +4 +PR +F +4 +C4 +F +4 +5 +T +F +5 +C5 +F +5 +6 +HC +F +6 +C6 +F +6 +7 +8 +7 +C7 +F +7 +8 +C8 +F +8 +F +F +F +F +F +F +4 +A2 +F +4 +5 +A3 +F +5 +6 +A4 +F +6 +7 +A5 +F +7 +8 +A6 +F +8 +3 +A1 +F +3 +FS +F +C10 +C11 +C12 +C13 +C14 +C15 +C16 +MID +*MAT_BAMMAN_DAMAGE +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +E +PR +T +HC +C1 +C2 +C3 +C4 +C5 +C6 +C7 +C8 +C9 +C10 +C11 +C12 +C13 +C14 +C15 +C16 +Mass density +Young’s modulus (psi) +Poisson’s ratio +Initial temperature (°R, degrees Rankine) +Heat generation coefficient (°R⁄psi) +Psi +°R +Psi +°R +1/s +°R +1/psi +°R +Psi +oR +1/psi-s +°R +1/psi +°R +psi +°R +VARIABLE +DESCRIPTION +C17 +C18 +A1 +A2 +A3 +A4 +A5 +A6 +N +D0 +FS +1/psi-s +°R +1, initial value of internal state variable 1 +2, initial value of internal state variable 2 +3, initial value of internal state variable 3 +4, initial value of internal state variable 4 +α5, initial value of internal state variable 5 +α6, initial value of internal state variable 6 +Exponent in damage evolution +Initial damage (porosity) +Failure strain for erosion. +Remarks: +The evolution of the damage parameter, φ is defined by Bammann et al. [1990] +in which +𝜙̇ = 𝛽 [ +(1 − 𝜙)𝑁 − (1 − 𝜙)] +∣𝑫𝑝∣ +𝛽 = sinh [ +2(2𝑁 − 1)𝑝 +(2𝑁 − 1)𝜎̅̅̅̅̅ +] +where p is the pressure and 𝜎̅̅̅̅̅ is the effective stress. +*MAT_CLOSED_CELL_FOAM +This is Material Type 53. This allows the modeling of low density, closed cell +polyurethane foam. It is for simulating impact limiters in automotive applications. The +effect of the confined air pressure is included with the air being treated as an ideal gas. +The general behavior is isotropic with uncoupled components of the stress tensor. +3 +E +F +3 +4 +A +F +4 +5 +B +F +5 +6 +C +F +6 +7 +P0 +F +7 +8 +PHI +F +8 + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +Variable +GAMA0 +LCID +Type +F +I + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +E +A +B +C +P0 +PHI +Young’s modulus +a, factor for yield stress definition, see notes below. +b, factor for yield stress definition, see notes below. +c, factor for yield stress definition, see notes below. +Initial foam pressure, P0 +Ratio of foam to polymer density, φ +GAMA0 +Initial volumetric strain, γ0. The default is zero. +DESCRIPTION +Optional load curve defining the von Mises yield stress versus +−𝛾. If the load curve ID is given, the yield stress is taken from the +curve and the constants a, b, and c are not needed. The load +curve is defined in the positive quadrant, i.e., positive values of 𝛾 +are defined as negative values on the abscissa. + VARIABLE +LCID +Remarks: +A rigid, low density, closed cell, polyurethane foam model developed at Sandia +Laboratories [Neilsen, Morgan and Krieg 1987] has been recently implemented for +modeling impact limiters in automotive applications. A number of such foams were +tested at Sandia and reasonable fits to the experimental data were obtained. +In some respects this model is similar to the crushable honeycomb model type 26 in that +the components of the stress tensor are uncoupled until full volumetric compaction is +achieved. + However, unlike the honeycomb model this material possesses no +directionality but includes the effects of confined air pressure in its overall response +characteristics. +𝜎𝑖𝑗 = 𝜎𝑖𝑗 +sk − 𝛿𝑖𝑗𝜎 air +where 𝜎𝑖𝑗 +𝑠𝑘 is the skeletal stress and 𝜎 𝑎𝑖𝑟 is the air pressure computed from the equation: +𝜎 air = − +𝑝0𝛾 +1 + 𝛾 − 𝜙 +where p0 is the initial foam pressure, usually taken as the atmospheric pressure, and γ +defines the volumetric strain +𝛾 = 𝑉 − 1 + 𝛾0 +where V is the relative volume, defined as the ratio of the current volume to the initial +volume, and γ0 is the initial volumetric strain, which is typically zero. The yield +condition is applied to the principal skeletal stresses, which are updated independently +of the air pressure. We first obtain the skeletal stresses: +and compute the trial stress, σskt +𝜎𝑖𝑗 +sk = 𝜎𝑖𝑗 + 𝜎𝑖𝑗𝜎 air +skt = 𝜎𝑖𝑗 +𝜎𝑖𝑗 +sk + 𝐸 𝜀̇𝑖𝑗 Δ𝑡 +where E is Young’s modulus. Since Poisson’s ratio is zero, the update of each stress +component is uncoupled and 2G = E where G is the shear modulus. The yield condition +is applied to the principal skeletal stresses such that, if the magnitude of a principal trial +stress component, 𝜎𝑖 +𝑠𝑘𝑡, exceeds the yield stress, σ +y, then +sk = min(𝜎𝑦, ∣𝜎𝑖 +𝜎𝑖 +skt∣) +skt +skt∣ +𝜎𝑖 +∣𝜎𝑖 +The yield stress is defined by +𝜎𝑦 = 𝑎 + 𝑏(1 + 𝑐𝛾) +where a, b, and c are user defined input constants and γ is the volumetric strain as +defined above. After scaling the principal stresses they are transformed back into the +global system and the final stress state is computed +𝜎𝑖𝑗 = 𝜎𝑖𝑗 +sk − 𝛿𝑖𝑗𝜎 air. +*MAT_ENHANCED_COMPOSITE_DAMAGE +These are Material Types 54 - 55 which are enhanced versions of the composite model +material type 22. Arbitrary orthotropic materials, e.g., unidirectional layers in +composite shell structures can be defined. Optionally, various types of failure can be +specified following either the suggestions of [Chang and Chang 1987b] or [Tsai and Wu +1971]. In addition special measures are taken for failure under compression. See +[Matzenmiller and Schweizerhof 1991]. +By using the user defined +integration rule, see *INTEGRATION_SHELL, the +constitutive constants can vary through the shell thickness. For all shells, except the +DKT formulation, laminated shell theory can be activated to properly model the +transverse shear deformation. Lamination theory is applied to correct for the +assumption of a uniform constant shear strain through the thickness of the shell. +For sandwich shells where the outer layers are much stiffer than the inner layers, the +response will tend to be too stiff unless lamination theory is used. To turn on +lamination theory see *CONTROL_SHELL. A damage model for transverse shear strain +to model interlaminar shear failure is available. The definition of minimum stress limits +is available for thin/thick shells and solids. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +EA +F +3 +4 +EB +F +4 +5 +EC +F +5 +Variable +GAB +GBC +GCA +(KF) +AOPT +2WAY +Type +F + Card 3 +1 +F +2 +F +3 +Variable +Type +F +F +4 +A1 +F +5 +A2 +F +6 +7 +8 +PRBA +PRCA +PRCB +F +6 +F +6 +F +7 +TI +F +7 +F +8 +8 +A3 +MANGLE +F +Card 4 +Variable +1 +V1 +Type +F + Card 5 +1 +2 +V2 +F +2 +3 +V3 +F +3 +4 +D1 +F +4 +5 +D2 +F +5 +6 +7 +8 +D3 +DFAILM +DFAILS +F +6 +F +7 +F +8 +Variable +TFAIL +ALPH +SOFT +FBRT +YCFAC +DFAILT +DFAILC +EFS +Type +F +F +F +F +F + Card 6 +Variable +1 +XC +Type +F +2 +XT +F +3 +YC +F +4 +YT +F +5 +SC +F +F +6 +F +7 +F +8 +CRIT +BETA +F +F +Optional Card 7 (only for CRIT = 54) + Card 7 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PFL +EPSF +EPSR +TSMD +SOFT2 +Type +F +F +F +F +F +Optional Card 8 (only for CRIT = 54) + Card 8 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SLIMT1 +SLIMC1 +SLIMT2 +SLIMC2 +SLIMS +NCYRED +SOFTG +Type +F +F +F +F +F +F +Optional Card 9 (only for CRIT = 54) + Card 9 +1 +2 +3 +4 +5 +Variable +LCXC +LCXT +LCYC +LCYT +LCSC +Type +I +I +I +I +I +7 +8 +6 +DT +F + VARIABLE +DESCRIPTION +MID +RO +EA +EB +EC +PRBA +PRCA +PRCB +GAB +GBC +GCA +(KF) +AOPT +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +𝐸𝑎, Young’s modulus - longitudinal direction +𝐸𝑏, Young’s modulus - transverse direction +𝐸𝑐, Young’s modulus - normal direction +𝜈𝑏𝑎, Poisson’s ratio 𝑏𝑎 +𝜈𝑐𝑎, Poisson’s ratio 𝑐𝑎 +𝜈𝑐𝑏, Poisson’s ratio 𝑐𝑏 +𝐺𝑎𝑏, shear modulus 𝑎𝑏 +𝐺𝑏𝑐, shear modulus 𝑏𝑐 +𝐺𝑐𝑎, shear modulus 𝑐𝑎 +Bulk modulus of failed material (not used) +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then, for shells only, rotated about +the shell element normal by an angle MANGLE. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +VARIABLE +DESCRIPTION +rotating the material axes about the element normal by +an angle (MANGLE) from a line in the plane of the el- +ement defined by the cross product of the vector v with +the element normal. +EQ.4.0: locally orthotropic in cylindrical coordinate system with +the material axes determined by a vector 𝐯, and an +originating point, 𝐩, which define the centerline axis. +This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +2WAY +Flag to turn on 2-way fiber action. +EQ.0.0: Standard unidirectional behavior. +EQ.1.0: 2-way fiber behavior. The meaning of the fields +DFAILT, DFAILC, YC, YT, SLIMT2 and SLIMC2 are +altered if this flag is set. This option is only available +for MAT 54 using thin shells. +TI +Flag to turn on transversal isotropic behavior for MAT_054 solid +elements. +EQ.0.0: Standard unidirectional behavior. +EQ.1.0: transversal isotropic behavior . +A1, A2, A3 +Define components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Define components of vector 𝐯 for AOPT = 3. +D1, D2, D3 +Define components of vector 𝐝 for AOPT = 2. +MANGLE +Material angle in degrees for AOPT = 0 (shells only) and +AOPT = 3. MANGLE may be overridden on the element card, +see *ELEMENT_SHELL_BETA and *ELEMENT_SOLID_ORTHO. +VARIABLE +DFAILM +DESCRIPTION +Maximum strain for matrix straining in tension or compression +(active only for MAT_054 and only if DFAILT > 0). The layer in +the element is completely removed after the maximum strain in +the matrix direction is reached. The input value is always +positive. +DFAILS +Maximum tensorial shear strain (active only for MAT_054 and +only if DFAILT > 0). The layer in the element is completely +removed after the maximum shear strain is reached. The input +value is always positive. +TFAIL +Time step size criteria for element deletion: +tfail ≤ 0: +no element deletion by time step size. The +crashfront algorithm only works if tfail is set to a +value above zero. +0 < tfail ≤ 0.1: element is deleted when its time step is smaller +than the given value, +tfail > 0.1: +element is deleted when the quotient of the +actual time step and the original time step drops +below the given value. +ALPH +SOFT +Shear stress parameter for the nonlinear term, see Material 22. +Softening reduction factor for material strength in crashfront +elements (default = 1.0). TFAIL must be greater than zero to +activate this option. +FBRT +Softening for fiber tensile strength: +EQ.0.0: tensile strength = XT +GT.0.0: tensile strength = XT, reduced to XT × FBRT after +failure has occurred in compressive matrix mode. +YCFAC +Reduction factor for compressive fiber strength after matrix +compressive failure (MAT_054 only). The compressive strength +in the fiber direction after compressive matrix failure is reduced +to: +𝑋𝑐 = YCFAC × 𝑌𝑐, +(default: YCFAC = 2.0) +VARIABLE +DFAILT +DESCRIPTION +Maximum strain for fiber tension (MAT_054 only). (Maximum +1 = 100% strain). The layer in the element is completely removed +after the maximum tensile strain in the fiber direction is reached. +If a nonzero value is given for DFAILT, a nonzero, negative value +must also be provided for DFAILC. +If the 2-way fiber flag is set then DFAILT is the fiber tensile +failure strain in the 𝑎 and 𝑏 directions. +DFAILC +EFS +XC +XT +YC +for +fiber compression +(MAT_054 only). +Maximum strain +(Maximum -1 = 100% compression). The layer in the element is +completely removed after the maximum compressive strain in the +fiber direction is reached. The input value should be negative +and is required if DFAILT > 0. +If the 2-way fiber flag is set then DFAILC is the fiber compressive +failure strain in the 𝑎 and 𝑏 directions. +Effective failure strain (MAT_054 only). +Longitudinal compressive strength (absolute value is used). +GE.0.0: Poisson effect (PRBA) after failure is active. +LT.0.0: Poisson effect after failure is not active, i.e. PRBA = 0. +Longitudinal tensile strength, see below. +Transverse compressive strength, 𝑏-axis (positive value), see +below. +If the 2-way fiber flag is set then YC is the fiber compressive +failure stress in the 𝑏 direction. +YT +Transverse tensile strength, 𝑏-axis, see below. +If the 2-way fiber flag is set then YT is the fiber tensile failure +stress in the 𝑏 direction. +SC +Shear strength, ab plane, see below. +VARIABLE +DESCRIPTION +CRIT +Failure criterion (material number): +BETA +PFL +EPSF +EPSR +TSMD +SOFT2 +SLIMT1 +SLIMC1 +SLIMT2 +EQ.54.0: Chang criterion for matrix failure (as Material 22) +(default), +EQ.55.0: Tsai-Wu criterion for matrix failure. +Weighting factor for shear term in tensile fiber mode (MAT_054 +only). (0.0 ≤ BETA ≤ 1.0) +Percentage of layers which must fail until crashfront is initiated. +E.g. |PFL| = 80.0, then 80% of layers must fail until strengths are +reduced in neighboring elements. Default: all layers must fail. A +single layer fails if 1 in-plane IP fails (PFL > 0) or if 4 in-plane IPs +fail (PFL < 0). (MAT_054 only, thin and thick shells). +Damage initiation transverse shear strain. (MAT_054 only). +Final rupture transverse shear strain. (MAT_054 only). +Transverse shear maximum damage, default = 0.90. (MAT_054 +only,). +Optional “orthogonal” softening reduction factor for material +strength in crashfront elements (default = 1.0). See remarks +(MAT_054 only, thin and thick shells). +Factor to determine the minimum stress limit after stress +maximum (fiber tension). Similar to *MAT_058 (MAT_054 only). +Factor to determine the minimum stress limit after stress +maximum (fiber compression). Similar to *MAT_058 (MAT_054 +only). +Factor to determine the minimum stress limit after stress +maximum (matrix tension). Similar to *MAT_058 (MAT_054 +only). +If the 2-way fiber flag is set then SLIMT2 is the factor to determine +the minimum stress limit after tensile failure stress is reached in +the 𝑏 fiber direction. +VARIABLE +SLIMC2 +SLIMS +NCYRED +SOFTG +LCXC +LCXT +LCYC +LCYT +LCSC +DESCRIPTION +Factor to determine the minimum stress limit after stress +maximum (matrix compression). Similar to *MAT_058 (MAT_054 +only). +If the 2-way fiber flag is set then SLIMC2 is the factor to +determine the minimum stress limit after compressive failure +stress is reached in the 𝑏 fiber direction. +Factor to determine the minimum stress limit after stress +maximum (shear). Similar to *MAT_058 (MAT_054 only). +Number of cycles for stress reduction from maximum to +minimum (MAT_054 only). +Softening reduction factor for transverse shear moduli GBC and +GCA in crashfront elements (default = 1.0) (MAT_054 only, thin +and thick shells). +Load curve ID for XC vs. strain rate (XC is ignored with that +option) +Load curve ID for XT vs. strain rate (XT is ignored with that +option) +Load curve ID for YC vs. strain rate (YC is ignored with that +option) +Load curve ID for YT vs. strain rate (YT is ignored with that +option) +Load curve ID for SC vs. strain rate (SC is ignored with that +option) +DT +Strain rate averaging option. +EQ.0.0: Strain rate is evaluated using a running average. +LT.0.0: Strain rate is evaluated using average of last 11 time +steps. +GT.0.0: Strain rate is averaged over the last DT time units. +Material Formulation: +The Chang/Chang (MAT_54) criteria is given as follows: +for the tensile fiber mode, +𝜎𝑎𝑎 > 0 ⇒ 𝑒𝑓 +2 = ( +) +𝜎𝑎𝑎 +𝑋𝑡 ++ 𝛽 ( +𝜎𝑎𝑏 +𝑆𝑐 +) +− 1, +2 ≥ 0 ⇒ failed +𝑒𝑓 +2 < 0 ⇒ elastic +𝑒𝑓 +𝐸𝑎 = 𝐸𝑏 = 𝐺𝑎𝑏 = 𝜈𝑏𝑎 = 𝜈𝑎𝑏 = 0 +for the compressive fiber mode, +𝜎𝑎𝑎 < 0 ⇒ 𝑒𝑐 +2 = ( +− 1, +) +𝜎𝑎𝑎 +𝑋𝑐 +2 ≥ 0 ⇒ failed +𝑒𝑐 +2 < 0 ⇒ elastic +𝑒𝑐 +𝐸𝑎 = 𝜈𝑏𝑎 = 𝜈𝑎𝑏 = 0 +for the tensile matrix mode, +𝜎𝑏𝑏 > 0 ⇒ 𝑒𝑚 +2 = ( +𝜎𝑏𝑏 +𝑌𝑡 +) ++ ( +𝜎𝑎𝑏 +𝑆𝑐 +) +− 1, +2 ≥ 0 ⇒ failed +𝑒𝑚 +2 < 0 ⇒ elastic +𝑒𝑚 +𝐸𝑏 = 𝜈𝑏𝑎 = 0 ⇒ 𝐺𝑎𝑏 = 0, +and for the compressive matrix mode, +𝜎𝑏𝑏 < 0 ⇒ 𝑒𝑑 +2 = ( +𝜎𝑏𝑏 +2𝑆𝑐 +) ++ +) +𝑌𝑐 +2𝑆𝑐 +⎢⎡( +⎣ +− 1 +⎥⎤ 𝜎𝑏𝑏 +𝑌𝑐 +⎦ ++ ( +) +𝜎��𝑏 +𝑆𝑐 +− 1, +2 ≥ 0 ⇒ failed +𝑒𝑑 +2 < 0 ⇒ elastic +𝑒𝑑 +𝐸𝑏 = 𝜈𝑏𝑎 = 𝜈𝑎𝑏 = 0 ⇒ 𝐺𝑎𝑏 = 0 +𝑋𝑐 = 2𝑌𝑐, for 50% fiber volume +If the 2-way fiber flag is set then the failure criteria for tensile and compressive fiber +failure in the local X direction are unchanged. For the local 𝑦-direction, the same failure +criteria as for the 𝑥-direction fibers are used. +Tension, 𝑦-direction, +𝜎𝑏𝑏 > 0 ⇒ 𝑒𝑓 +2 = ( +) +𝜎𝑏𝑏 +𝑌𝑡 ++ 𝛽 ( +𝜎𝑎𝑏 +𝑆𝑐 +) − 1, +2 ≥ 0 ⇒ failed +𝑒𝑓 +2 < 0 ⇒ elastic +𝑒𝑓 +Compressive 𝑦-direction, +𝜎𝑏𝑏 < 0 ⇒ 𝑒𝑐 +2 = ( +𝜎𝑏𝑏 +𝑌𝑐 +) +− 1, +2 ≥ 0 ⇒ failed +𝑒𝑐 +2 < 0 ⇒ elastic +𝑒𝑐 +Matrix failure criterion, +2 = ( +𝑒𝑓 +) +𝜎𝑎𝑏 +𝑆𝑐 +− 1 +In the Tsai-Wu (MAT_055) criteria the tensile and compressive fiber modes are treated +as in the Chang-Chang criteria. The failure criterion for the tensile and compressive +matrix mode is given as: +2 = +𝑒md +𝜎𝑏𝑏 +𝑌𝑐𝑌𝑡 ++ ( +) +𝜎𝑎𝑏 +𝑆𝑐 ++ +(𝑌𝑐 − 𝑌𝑡) 𝜎𝑏𝑏 +𝑌𝑐𝑌𝑡 +− 1, +2 ≥ 0 ⇒ failed +𝑒𝑚𝑑 +2 < 0 ⇒ elastic +𝑒𝑚𝑑 +For β = 1 we get the original criterion of Hashin [1980] in the tensile fiber mode. For +β = 0 we get the maximum stress criterion which is found to compare better to +experiments. +In MAT_054, failure can occur in any of four different ways: +1. +2. +3. +4. +If DFAILT is zero, failure occurs if the Chang-Chang failure criterion is satisfied +in the tensile fiber mode. +If DFAILT is greater than zero, failure occurs if: +- +- +- +the fiber strain is greater than DFAILT or less than DFAILC +if absolute value of matrix strain is greater than DFAILM +if absolute value of tensorial shear strain is greater than DFAILS +If EFS is greater than zero, failure occurs if the effective strain is greater than +EFS. +If TFAIL is greater than zero, failure occurs according to the element timestep +as described in the definition of TFAIL above. +When failure has occurred in all the composite layers (through-thickness integration +points), the element is deleted. Elements which share nodes with the deleted element +become “crashfront” elements and can have their strengths reduced by using the SOFT +parameter with TFAIL greater than zero. An earlier initiation of crashfront elements is +possible by using parameter PFL. +Reduction +by SOFT2 +(orthogonal +) +Reduction +by +0.5(SOFT+SOFT2) +Reduction +By SOFT (parallel) +Figure M54-1. Direction dependent softening +An optional direction dependent strength reduction can be invoked by setting +0 < SOFT2 < 1. Then, SOFT equals a strength reduction factor for fiber parallel failure +and SOFT2 equals a strength reduction factor for fiber orthogonal failure. Linear +interpolation is used for angles in between. See Figure M54-1. +Information about the status in each layer (integration point) and element can be +plotted using additional integration point variables. The number of additional +integration point variables for shells written to the LS-DYNA database is input by the +*DATABASE_EXTENT_BINARY definition as variable NEIPS. For Models 54 and 55 +these additional variables are tabulated below (i = shell integration point): +History +Variable +1 ef(i) +Description +tensile fiber mode +Value +LS-PrePost +History Variable +2 ec(i) +compressive fiber mode +3 em(i) tensile matrix mode +1 – elastic +4 ed(i) +compressive +mode +5 efail max[ef(ip)] +matrix +0 – failed +6 dam damage parameter +−1 – element intact +10−8 – element +crashfront ++1 – element failed +in +1 +2 +3 +4 +5 +6 +These variables can be plotted in LS-PrePost element history variables 1 to 6. The +following components, defined by the sum of failure indicators over all through- +thickness integration points, are stored as element component 7 instead of the effective +plastic strain. +Description +Integration point +nip +nip +∑ 𝑒𝑓 (𝑖) +𝑖=1 +nip +nip +∑ 𝑒𝑐(𝑖) +𝑖=1 +nip +nip +∑ 𝑒𝑚(𝑖) +𝑖=1 +1 +2 +3 +In an optional damage model for transverse shear strain, out-of-plane stiffness (GBC +and GCA) can get linearly decreased to model interlaminar shear failure. Damage +starts when effective transverse shear strain +eff = √𝜀𝑦𝑧 +𝜀56 +2 +2 + 𝜀𝑧𝑥 +reaches EPSF. Final rupture occurs when effective transverse shear strain reaches EPSR. +A maximum damage of TSMD (0.0 < TSMD < 0.99) cannot be exceeded. See Figure +M54-2. +transverse shear stiffness +transverse shear stiffness +GBC, +GBC, +GCA +GCA +D=0 +D = 0 +D=TSMD +D = TSMD +EPSF +EPSF +EPSR +EPSR +transverse shear strain +transverse shear strain +Figure M54-3. Linear Damage for transverse shear behavior +Figure M54-2. Linear Damage for transverse shear behavior +Additional Remarks: +1. TI-Flag +(Transversal isotropic behavior for *MAT_054 solid elements). +The behavior in the b-c-plane is assumed to be isotropic, thus the elastic constants +EC, PRCA and GCA are ignored and set according to the given values EA, EB, +PRAB, GAB. Damage in transverse shear (EPSF, EPSR, TSMD, SOFTG) is ignored. +The failure criterion is evaluated by replacing 𝜎bb and 𝜎ab with the corresponding +stresses 𝜎11 and 𝜎a1 in a principal stress frame rotated around the local a-axis. +The principal axes 1 and 2 in the b-c plane are chosen such that |𝜎11| ≥ |𝜎22| is +fulfilled. +*MAT_LOW_DENSITY_FOAM +This is Material Type 57 for modeling highly compressible low density foams. Its main +applications are for seat cushions and padding on the Side Impact Dummies (SID). +Optionally, a tension cut-off failure can be defined. A table can be defined if thermal +effects are considered in the nominal stress versus strain behavior. Also, see the notes +below. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +LCID +F +Default +Remarks +5 +TC +F +1020 + Card 2 +1 +2 +3 +4 +5 +6 +HU +F +1. +3 +6 +7 +8 +BETA +DAMP +F +F +0.05 +8 +1 +7 +Variable +SHAPE +FAIL +BVFLAG +ED +BETA1 +KCON +REF +Type +F +F +F +F +F +F +F +Default +1.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Remarks +3 +2 +5 +5 +6 + VARIABLE +DESCRIPTION +MID +RO +E +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus used in tension. For implicit problems E is set +to the initial slope of load curve LCID. +VARIABLE +LCID +TC +HU +BETA +DAMP +DESCRIPTION +Load curve or table ID, see *DEFINE_CURVE, for the nominal +stress versus strain curve definition. If a table is used, a family of +curves is defined each corresponding to a discrete temperature, +see *DEFINE_TABLE. +Cut-off for the nominal tensile stress τi +Hysteretic unloading factor between 0 and 1 (default = 1, i.e., no +energy dissipation), see also Figure M57-1. +β, decay constant to model creep in unloading +Viscous coefficient (.05 < recommended value <.50) to model +damping effects. +LT.0.0: |DAMP| is the load curve ID, which defines the +damping constant as a function of the maximum strain +in compression defined as: +𝜀max = max(1 − 𝜆1, 1 − 𝜆2, 1. −𝜆3). +In tension, the damping constant is set to the value corre- +sponding to the strain at 0. The abscissa should be defined +from 0 to 1. +SHAPE +Shape factor for unloading. Active for nonzero values of the +hysteretic unloading factor. Values less than one reduces the +energy dissipation and greater than one increases dissipation, see +also Figure M57-1. +FAIL +Failure option after cutoff stress is reached: +EQ.0.0: tensile stress remains at cut-off value, +EQ.1.0: tensile stress is reset to zero. +BVFLAG +Bulk viscosity activation flag, see remark below: +EQ.0.0: no bulk viscosity (recommended), +EQ.1.0: bulk viscosity active. +ED +Optional Young's relaxation modulus, 𝐸𝑑, for rate effects. See +Remark 5. +BETA1 +Optional decay constant, 𝛽1. +Typical unloading +curves determined by +the hysteretic unloading +factor. With the shape +factor equal to unity. +Typical unloading for +a large shape factor, e.g. +5.0-8.0, and a small +hystereticfactor, e.g., 0.010. +Unloading +curves +Strain +Strain +Figure M57-1. Behavior of the low density urethane foam model + VARIABLE +KCON +DESCRIPTION +Stiffness coefficient for contact interface stiffness. If undefined +the maximum slope in stress vs. strain curve is used. When the +maximum slope is taken for the contact, the time step size for this +material is reduced for stability. In some cases Δt may be +significantly smaller, and defining a reasonable stiffness is +recommended. +REF +Use reference geometry to initialize the stress tensor. The +reference geometry is defined by the keyword:*INITIAL_FOAM_- +REFERENCE_GEOMETRY . +EQ.0.0: off, +EQ.1.0: on. +Material Formulation: +The compressive behavior is illustrated in Figure M57-1 where hysteresis on unloading +is shown. This behavior under uniaxial loading is assumed not to significantly couple +in the transverse directions. In tension the material behaves in a linear fashion until +tearing occurs. Although our implementation may be somewhat unusual, it was +motivated by Storakers [1986]. +The model uses tabulated input data for the loading curve where the nominal stresses +are defined as a function of the elongations, 𝜀𝑖, which are defined in terms of the +principal stretches, 𝜆𝑖, as: +𝜀𝑖 = 𝜆���� − 1 +The principal stretches are stored as extra history variables 16, 17, and 18 if ED = 0 and +as extra history variables 28, 29, and 30 if ED > 0. The stretch ratios are found by +solving for the eigenvalues of the left stretch tensor, 𝑉𝑖𝑗, which is obtained via a polar +decomposition of the deformation gradient matrix, 𝐹𝑖𝑗. Recall that, +𝐹𝑖𝑗 = 𝑅𝑖𝑘𝑈𝑘𝑗 = 𝑉𝑖𝑘𝑅𝑘𝑗 +The update of Vij follows the numerically stable approach of Taylor and Flanagan +[1989]. After solving for the principal stretches, we compute the elongations and, if the +elongations are compressive, the corresponding values of the nominal stresses, 𝜏𝑖 are +interpolated. If the elongations are tensile, the nominal stresses are given by +and the Cauchy stresses in the principal system become +𝜏𝑖 = 𝐸𝜀𝑖 +𝜎𝑖 = +𝜏𝑖 +𝜆𝑗𝜆𝑘 +The stresses can now be transformed back into the global system for the nodal force +calculations. +Remarks: +1. When hysteretic unloading is used the reloading will follow the unloading +curve if the decay constant, β, is set to zero. If β is nonzero the decay to the +original loading curve is governed by the expression: +1 − 𝑒−𝛽𝑡 +2. The bulk viscosity, which generates a rate dependent pressure, may cause an +unexpected volumetric response and, consequently, it is optional with this +model. +3. The hysteretic unloading factor results in the unloading curve to lie beneath the +loading curve as shown in Figure M57-1 This unloading provides energy dissi- +pation which is reasonable in certain kinds of foam. +4. Note that since this material has no effective plastic strain, the internal energy +per initial volume is written into the output databases. +5. Rate effects are accounted for through linear viscoelasticity by a convolution +integral of the form +𝜎𝑖𝑗 +𝑟 = ∫ 𝑔𝑖𝑗𝑘𝑙 +(𝑡 − 𝜏) +∂𝜀𝑘𝑙 +∂𝜏 +𝑑𝜏 +where 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) is the relaxation function. The stress tensor, 𝜎𝑖𝑗 +stresses determined from the foam, 𝜎𝑖𝑗 +taken as the summation of the two contributions: +𝑟 , augments the +𝑓 ; consequently, the final stress, 𝜎𝑖𝑗, is +𝜎𝑖𝑗 = 𝜎𝑖𝑗 +𝑓 + 𝜎𝑖𝑗 +𝑟 . +Since we wish to include only simple rate effects, the relaxation function is +represented by one term from the Prony series: +given by, +𝑔(𝑡) = 𝛼0 + ∑ 𝛼𝑚 +𝑚=1 +𝑒−𝛽 𝑡 +𝑔(𝑡) = 𝐸𝑑𝑒−𝛽1 𝑡 +This model is effectively a Maxwell fluid which consists of a damper and spring +in series. We characterize this in the input by a Young's modulus, 𝐸𝑑, and de- +cay constant, 𝛽1. The formulation is performed in the local system of principal +stretches where only the principal values of stress are computed and triaxial +coupling is avoided. Consequently, the one-dimensional nature of this foam +material is unaffected by this addition of rate effects. The addition of rate ef- +fects necessitates twelve additional history variables per integration point. The +cost and memory overhead of this model comes primarily from the need to +“remember” the local system of principal stretches. +6. The time step size is based on the current density and the maximum of the +instantaneous loading slope, 𝐸, and KCON. If KCON is undefined the maxi- +mum slope in the loading curve is used instead. +*MAT_LAMINATED_COMPOSITE_FABRIC +This is Material Type 58. Depending on the type of failure surface, this model may be +used to model composite materials with unidirectional layers, complete laminates, and +woven fabrics. This model is implemented for shell and thick shell elements +(ELFORM = 1 and 2). + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +EA +F +3 +4 +EB +F +4 +5 +6 +7 +8 +(EC) +PRBA +TAU1 +GAMMA1 +F +5 +F +6 +F +7 +F +8 +Variable +GAB +GBC +GCA +SLIMT1 +SLIMC1 +SLIMT2 +SLIMC2 +SLIMS +Type +F + Card 3 +1 +F +2 +F +3 +F +4 +Variable +AOPT +TSIZE +ERODS +SOFT +Type +F +F +F +F + Card 4 +Variable +1 +XP +Type +F + Card 5 +Variable +1 +V1 +Type +F +LS-DYNA R10.0 +2 +YP +F +2 +V2 +F +3 +ZP +F +3 +V3 +F +4 +A1 +F +4 +D1 +F +F +5 +FS +F +5 +A2 +F +5 +D2 +F +F +6 +F +7 +F +8 +EPSF +EPSR +TSMD +F +6 +A3 +F +6 +D3 +F +F +7 +F +8 +PRCA +PRCB +F +8 +F +7 +BETA +Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +E11C +E11T +E22C +E22T +GMS +Type +F +F +F +F +F + Card 7 +Variable +1 +XC +Type +F +2 +XT +F +3 +YC +F +4 +YT +F +5 +SC +F +6 +7 +8 +First Optional Strain Rate Dependence Card. + Card 8 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCXC +LCXT +LCYC +LCYT +LCSC +LCTAU +LCGAM +DT +Type +I +I +I +I +I +I +I +F +Second Optional Strain Rate Dependence Card. + Card 9 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCE11C +LCE11T +LCE22C +LCE22T +LCGMS +LCEFS +Type +I +I +I +I +I +I + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +VARIABLE +EA +DESCRIPTION +GT.0.0: 𝐸𝑎, Young’s modulus - longitudinal direction +LT.0.0: Load curve ID or Table ID = (-EA) +Load Curve. When (-EA) is equal to a Load curve ID, +it is taken as defining the uniaxial elastic stress vs. +strain behavior in longitudinal direction. +Tabular Data. When (-EA) is equal to a Table ID, it +defines for each strain rate value a Load curve ID giv- +ing the uniaxial elastic stress vs. strain behavior in +longitudinal direction. +Logarithmically Defined Tables. If the first uniaxial +elastic stress vs. strain curve in the table corresponds +to a negative strain rate, LS-DYNA assumes that the +natural logarithm of the strain rate value is used for all +stress-strain curves. +EB +GT.0.0: 𝐸𝑏, Young’s modulus - transverse direction +LT.0.0: Load curve ID or Table ID = (-EB) +Load Curve. When (-EB) is equal to a Load curve ID, it +is taken as defining the uniaxial elastic stress vs. strain +behavior in transverse direction. +Tabular Data. When (-EB) is equal to a Table ID, it +defines for each strain rate value a Load curve ID giv- +ing the uniaxial elastic stress vs. strain behavior in +transverse direction. +Logarithmically Defined Tables. If the first uniaxial +elastic stress vs. strain curve in the table corresponds +to a negative strain rate, LS-DYNA assumes that the +natural logarithm of the strain rate value is used for all +stress-strain curves. +(EC) +PRBA +PRCA +PRCB +Ec, Young’s modulus - normal direction (not used) +𝜈𝑏𝑎, Poisson’s ratio ba +𝜈𝑐𝑎, Poisson’s ratio ca, can be defined in card 4, col. 7, +default = PRBA +𝜈𝑐𝑏, Poisson’s ratio cb, can be defined in card 4, col. 8, +default = PRBA +TAU1 +*MAT_LAMINATED_COMPOSITE_FABRIC +DESCRIPTION +𝜏1, stress limit of the first slightly nonlinear part of the shear +stress versus shear strain curve. The values 𝜏1 and 𝛾1 are used to +define a curve of shear stress versus shear strain. These values +are input if FS, defined below, is set to a value of -1. +GAMMA1 +𝛾1, strain limit of the first slightly nonlinear part of the shear +stress versus engineering shear strain curve. +GAB +GT.0.0: 𝐺𝑎𝑏, shear modulus ab direction +LT.0.0: Load curve ID or Table ID = (-GAB) +Load Curve. When (-GAB) is equal to a Load curve ID, +it is taken as defining the elastic shear stress vs. shear +strain behavior in ab direction. +Tabular Data. When (-GAB) is equal to a a Table ID, it +defines for each strain rate value a Load curve ID giv- +ing the elastic shear stress vs. shear strain behavior in +ab direction. +Logarithmically Defined Tables. If the first elastic +shear stress vs. shear strain curve in the table corre- +sponds to a negative strain rate, LS-DYNA assumes +that the natural logarithm of the strain rate value is +used for all shear stress-shear strain curves. +GBC +GCA +SLIMT1 +SLIMC1 +SLIMT2 +SLIMC2 +SLIMS +𝐺𝑏𝑐, shear modulus 𝑏𝑐 +𝐺𝑐𝑎, shear modulus 𝑐𝑎 +Factor to determine the minimum stress limit after stress +maximum (fiber tension). +Factor to determine the minimum stress limit after stress +maximum (fiber compression). +Factor to determine the minimum stress limit after stress +maximum (matrix tension). +Factor to determine the minimum stress limit after stress +maximum (matrix compression). +Factor to determine the minimum stress limit after stress +maximum (shear). +AOPT +Material axes option (see MAT_OPTION TROPIC_ELASTIC for a +VARIABLE +DESCRIPTION +more complete description): +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the shell ele- +ment normal by an angle BETA. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle (BETA) from a line in the plane of the element +defined by the cross product of the vector 𝐯 with the +element normal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). +TSIZE +Time step for automatic element deletion. +ERODS +Maximum effective strain for element layer failure. A value of +unity would equal 100% strain. +GT.0.0: fails when effective strain calculated assuming material +is volume preserving exceeds ERODS (old way). +LT.0.0: fails when effective strain calculated from the full +strain tensor exceeds |ERODS|. +SOFT +Softening reduction factor for strength in the crashfront. +transverse shear stiffness +GBC, +GCA +D = 0 +D = TSMD +EPSF +EPSR +transverse shear strain +Figure M58-1. Linear Damage for transverse shear behavior + VARIABLE +DESCRIPTION +FS +Failure surface type: +EQ.1.0: smooth failure surface with a quadratic criterion for +both the fiber (a) and transverse (b) directions. This +option can be used with complete laminates and fab- +rics. +EQ.0.0: smooth failure surface in the transverse (b) direction +with a limiting value in the fiber (a) direction. This +model is appropriate for unidirectional (UD) layered +composites only. +EQ.-1.: faceted failure surface. When the strength values are +reached then damage evolves in tension and compres- +sion for both the fiber and transverse direction. Shear +behavior is also considered. This option can be used +with complete laminates and fabrics. +EPSF +EPSR +Damage initiation transverse shear strain. +Final rupture transverse shear strain. +TSMD +Transverse shear maximum damage, default = 0.90. +XP, YP, ZP +Define coordinates of point 𝐩 for AOPT = 1. +A1, A2, A3 +Define components of vector 𝐚 for AOPT = 2. +V1, V2 V3 +Define components of vector 𝐯 for AOPT = 3. +D1, D2, D3 +Define components of vector 𝐝 for AOPT = 2. +VARIABLE +BETA +E11C +E11T +E22C +E22T +GMS +XC +XT +YC +YT +SC +LCXC +LCXT +LCYC +LCYT +DESCRIPTION +Material angle in degrees for AOPT = 0 and AOPT = 3. BETA +may be overridden on the element card, see *ELEMENT_- +SHELL_BETA. +Strain at longitudinal compressive strength, 𝑎-axis (positive). +Strain at longitudinal tensile strength, 𝑎-axis. +Strain at transverse compressive strength, 𝑏-axis. +Strain at transverse tensile strength, 𝑏-axis. +Engineering shear strain at shear strength, 𝑎𝑏 plane. +Longitudinal compressive strength (positive value). +Longitudinal tensile strength, see below. +Transverse compressive strength, 𝑏-axis (positive value), see +below. +Transverse tensile strength, 𝑏-axis, see below. +Shear strength, 𝑎𝑏 plane, see below. +Load curve ID defining longitudinal compressive strength XC vs. +strain rate (XC is ignored with that option). If the first strain rate +value in the curve is negative, it is assumed that all strain rate +values are given as natural logarithm of the strain rate. +Load curve ID defining longitudinal tensile strength XT vs. strain +rate (XT is ignored with that option) If the first strain rate value in +the curve is negative, it is assumed that all strain rate values are +given as natural logarithm of the strain rate. +Load curve ID defining transverse compressive strength YC vs. +strain rate (YC is ignored with that option) If the first strain rate +value in the curve is negative, it is assumed that all strain rate +values are given as natural logarithm of the strain rate. +Load curve ID defining transverse tensile strength YT vs. strain +rate (YT is ignored with that option) If the first strain rate value in +the curve is negative, it is assumed that all strain rate values are +given as natural logarithm of the strain rate. +LCSC +LCTAU +LCGAM +*MAT_LAMINATED_COMPOSITE_FABRIC +DESCRIPTION +Load curve ID defining shear strength SC vs. strain rate (SC is +ignored with that option) If the first strain rate value in the curve +is negative, it is assumed that all strain rate values are given as +natural logarithm of the strain rate. +Load curve ID defining TAU1 vs. strain rate (TAU1 is ignored +with that option). This value is only used for FS = -1. +If the first strain rate value in the curve is negative, it is assumed +that all strain rate values are given as natural logarithm of the +strain rate. +Load curve ID defining GAMMA1 vs. strain rate (GAMMA1 is +ignored with that option). This value is only used for FS = -1. +If the first strain rate value in the curve is negative, it is assumed +that all strain rate values are given as natural logarithm of the +strain rate. +DT +Strain rate averaging option. +EQ.0.0: Strain rate is evaluated using a running average. +LT.0.0: Strain rate is evaluated using average of last 11 time +steps. +GT.0.0: Strain rate is averaged over the last DT time units. +Load curve ID defining E11C vs. strain rate (E11C is ignored with +that option) If the first strain rate value in the curve is negative, it +is assumed that all strain rate values are given as natural +logarithm of the strain rate. +Load curve ID defining E11T vs. strain rate (E11T is ignored with +that option) If the first strain rate value in the curve is negative, it +is assumed that all strain rate values are given as natural +logarithm of the strain rate. +Load curve ID defining E22C vs. strain rate (E22C is ignored with +that option) If the first strain rate value in the curve is negative, it +is assumed that all strain rate values are given as natural +logarithm of the strain rate. +Load curve ID defining E22T vs. strain rate (E22T is ignored with +that option) If the first strain rate value in the curve is negative, it +is assumed that all strain rate values are given as natural +logarithm of the strain rate. +LCE11C +LCE11T +LCE22C +LCE22T +DESCRIPTION +Load curve ID defining GMS vs. strain rate (GMS is ignored with +that option) If the first strain rate value in the curve is negative, it +is assumed that all strain rate values are given as natural +logarithm of the strain rate. +Load curve ID defining ERODS vs. strain rate (ERODS is ignored +with that option). The full strain tensor is used to compute the +equivalent strain (new option). If the first strain rate value in the +curve is negative, it is assumed that all strain rate values are given +as natural logarithm of the strain rate. + VARIABLE +LCGMS +LCEFS +Remarks: +Parameters to control failure of an element layer are: ERODS, the maximum effective +strain, i.e., maximum 1 = 100% straining. The layer in the element is completely +removed after the maximum effective strain (compression/tension including shear) is +reached. +The stress limits are factors used to limit the stress in the softening part to a given value, +𝜎min = SLIM𝑥𝑥 × strength, +thus, the damage value is slightly modified such that elastoplastic like behavior is +achieved with the threshold stress. The SLIMxx fields may range between 0.0 and 1.0. +With a factor of 1.0, the stress remains at a maximum value identical to the strength, +which is similar to ideal elastoplastic behavior. For tensile failure a small value for +SLIMTx is often reasonable; however, for compression SLIMCx = 1.0 is preferred. This +is also valid for the corresponding shear value. +If SLIMxx is smaller than 1.0, then localization can be observed depending on the total +behavior of the lay-up. If the user is intentionally using SLIMxx < 1.0, it is generally +recommended to avoid a drop to zero and set the value to something in between 0.05 +and 0.10. Then elastoplastic behavior is achieved in the limit which often leads to less +numerical problems. Defaults for SLIM𝑥𝑥 = 10−8. +The crashfront-algorithm is started if and only if a value for TSIZE is input. Note that +time step size, with element elimination after the actual time step becomes smaller than +TSIZE. +The damage parameters can be written to the post processing database for each +integration point as the first three additional element variables and can be visualized. +τ +TAU1 +SC +GAMMA1 +GMS +SLIMS = 1.0 +SLIMS = 0.9 +SLIMS = 0.6 +γ +Figure M58-2. Stress-strain diagram for shear +Material models with FS = 1 or FS = -1 are favorable for complete laminates and fabrics, +as all directions are treated in a similar fashion. +For material model FS = 1 an interaction between normal stresses and the shear stresses +is assumed for the evolution of damage in the a and b-directions. For the shear damage +is always the maximum value of the damage from the criterion in a or b-direction is +taken. +For material model FS = -1 it is assumed that the damage evolution is independent of +any of the other stresses. A coupling is only present via the elastic material parameters +and the complete structure. +In tensile and compression directions and in a as well as in b- direction different failure +surfaces can be assumed. The damage values, however, increase only also when the +loading direction changes. +Special control of shear behavior of fabrics: +For fabric materials a nonlinear stress strain curve for the shear part for failure surface +FS = -1 can be assumed as given below. This is not possible for other values of FS. +The curve, shown in Figure M58-2 is defined by three points: +1. +2. +3. +the origin (0,0) is assumed, +the limit of the first slightly nonlinear part (must be input), stress (TAU1) and +strain (GAMMA1), see below. +the shear strength at failure and shear strain at failure. +In addition a stress limiter can be used to keep the stress constant via the SLIMS +parameter. This value must be less or equal 1.0 but positive, and leads to an +elastoplastic behavior for the shear part. The default is 10−8, assuming almost brittle +failure once the strength limit SC is reached. +*MAT_COMPOSITE_FAILURE_{OPTION}_MODEL +This is Material Type 59. +Available options include: +SHELL +SOLID +SPH +depending on the element type the material is to be used with, see *PART. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +EA +F +3 +Variable +GAB +GBC +GCA +Type +F +F +F + Card 3 +Variable +1 +XP +Type +F + Card 4 +Variable +1 +V1 +Type +F +2 +YP +F +2 +V2 +F +3 +ZP +F +3 +V3 +F +4 +EB +F +4 +KF +F +4 +A1 +F +4 +D1 +F +5 +EC +F +5 +6 +7 +8 +PRBA +PRCA +PRCB +F +6 +F +7 +F +8 +AOPT +MACF +F +I +5 +A2 +F +5 +D2 +F +6 +A3 +F +6 +D3 +F +7 +8 +7 +8 +BETA +Card 5 for SHELL Keyword Option. + Card 5 +1 +2 +3 +4 +Variable +TSIZE +ALP +SOFT +FBRT +Type +F +F +F +F +Card 6 for SHELL Keyword Option. + Card 6 +Variable +1 +XC +Type +F +2 +XT +F +3 +YC +F +4 +YT +F +5 +SR +F +5 +SC +F +7 +8 +6 +SF +F +6 +7 +8 +Card 5 for SPH and SOLID Keyword Options. + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SBA +SCA +SCB +XXC +YYC +ZZC +Type +F +F +F +F +F +F +Card 6 for SPH and SOLID Keyword Options. + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +XXT +YYT +ZZT +Type +F +F +F + VARIABLE +DESCRIPTION +MID +RO +EA +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Density +𝐸𝑎, Young’s modulus - longitudinal direction +EB +EC +PRBA +PRCA +PRCB +GAB +GBC +GCA +KF +AOPT +*MAT_COMPOSITE_FAILURE_{OPTION}_MODEL +DESCRIPTION +𝐸𝑏, Young’s modulus - transverse direction +𝐸𝑐, Young’s modulus - normal direction +𝜈𝑏𝑎, Poisson’s ratio ba +𝜈𝑐𝑎, Poisson’s ratio ca +𝜈𝑐𝑏, Poisson’s ratio cb +𝐺𝑎𝑏, Shear Modulus +𝐺𝑏𝑐, Shear Modulus +𝐺𝑐𝑎, Shear Modulus +Bulk modulus of failed material +Material axes option (SPH particles only support +AOPT = 2.0): +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then, for shells only, rotated about +the shell element normal by an angle BETA. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the 𝑎-direction. This option is for solid +elements only. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector 𝐯 with the +element normal. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector 𝐯, and +an originating point, 𝐩, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +VARIABLE +DESCRIPTION +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +MACF +Material axes change flag for brick elements. +EQ.1: No change, default, +EQ.2: switch material axes 𝑎 and 𝑏, +EQ.3: switch material axes 𝑎 and 𝑐, +EQ.4: switch material axes 𝑏 and 𝑐. +XP YP ZP +Define coordinates of point 𝐩 for AOPT = 1 and 4. +A1 A2 A3 +Define components of vector 𝐚 for AOPT = 2. +V1 V2 V3 +Define components of vector 𝐯 for AOPT = 3 and 4. +D1 D2 D3 +Define components of vector 𝐝 for AOPT = 2: +BETA +Material angle in degrees for AOPT = 0 (shells only) and +AOPT = 3, may be overridden on the element card, see *ELE- +MENT_SHELL_BETA or *ELEMENT_SOLID_ORTHO. +TSIZE +Time step for automatic element deletion +ALP +SOFT +FBRT +SR +SF +XC +XT +YC +YT +Nonlinear shear stress parameter +Softening reduction factor for strength in crush +Softening of fiber tensile strength +𝑠𝑟, reduction factor (default = 0.447) +𝑠𝑓 , softening factor (default = 0.0) +Longitudinal compressive strength, 𝑎-axis (positive value). +Longitudinal tensile strength, 𝑎-axis +Transverse compressive strength, 𝑏-axis (positive value). +Transverse tensile strength, 𝑏-axis +*MAT_COMPOSITE_FAILURE_{OPTION}_MODEL +DESCRIPTION +SC +Shear strength, 𝑎𝑏 plane: +GT.0.0: faceted failure surface theory, +LT.0.0: ellipsoidal failure surface theory. +SBA +SCA +SCB +XXC +YYC +ZZC +XXT +YYT +ZZT +In plane shear strength. +Transverse shear strength. +Transverse shear strength. +Longitudinal compressive strength 𝑎-axis (positive value). +Transverse compressive strength 𝑏-axis (positive value). +Normal compressive strength 𝑐-axis (positive value). +Longitudinal tensile strength 𝑎-axis. +Transverse tensile strength 𝑏-axis. +Normal tensile strength 𝑐-axis. +*MAT_ELASTIC_WITH_VISCOSITY +This is Material Type 60 which was developed to simulate forming of glass products +(e.g., car windshields) at high temperatures. Deformation is by viscous flow but elastic +deformations can also be large. The material model, in which the viscosity may vary +with temperature, is suitable for treating a wide range of viscous flow problems and is +implemented for brick and shell elements. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +V0 +F +3 +4 +A +F +4 +5 +B +F +5 +6 +C +F +6 +7 +8 +LCID +F +7 +8 +Variable +PR1 +PR2 +PR3 +PR4 +PR5 +PR6 +PR7 +PR8 +Type +F +F +F +F +F +F +F +F + Card 3 +Variable +1 +T1 +Type +F + Card 4 +Variable +1 +V1 +Type +F +2 +T2 +F +2 +V2 +F +3 +T3 +F +3 +V3 +F +4 +T4 +F +4 +V4 +F +5 +T5 +F +5 +V5 +F +6 +T6 +F +6 +V6 +F +7 +T7 +F +7 +V7 +F +8 +T8 +F +8 +V8 +Variable +1 +E1 +Type +F + Card 6 +1 +*MAT_ELASTIC_WITH_VISCOSITY +2 +E2 +F +2 +3 +E3 +F +3 +4 +E4 +F +4 +5 +E5 +F +5 +6 +E6 +F +6 +7 +E7 +F +7 +8 +E8 +F +8 +Variable +ALPHA1 +ALPHA2 +ALPHA3 +ALPHA4 +ALPHA5 +ALPHA6 +ALPHA7 +ALPHA8 +Type +F +F +F +F +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +V0 +A +B +C +LCID +T1, T2, +…, TN +PR1, PR2, +…, PRN +V1, V2, +…, VN +2-346 (EOS) +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Temperature independent dynamic viscosity coefficient, V0. If +defined, the temperature dependent viscosity defined below is +skipped, see type (i) and (ii) definitions for viscosity below. +Dynamic viscosity coefficient, see type (i) and (ii) definitions +below. +Dynamic viscosity coefficient, see type (i) and (ii) definitions +below. +Dynamic viscosity coefficient, see type (i) and (ii) definitions +below. +Load curve defining viscosity versus +temperature, see type (iii). (Optional) +Temperatures, define up to 8 values +Poisson’s ratios for the temperatures Ti +Corresponding dynamic viscosity coefficients (define only one if +VARIABLE +DESCRIPTION +E1, E2, +…, EN +Corresponding Young’s moduli coefficients (define only one if +not varying with temperature) +Corresponding thermal expansion coefficients +ALPHA1, …, +ALPHAN. +Remarks: +Volumetric behavior is treated as linear elastic. The deviatoric strain rate is considered +to be the sum of elastic and viscous strain rates: +′ = 𝛆̇elastic +𝛆̇total +′ +′ ++ 𝛆̇viscous += +𝛔̇′ +2𝐺 ++ +𝛔′ +2𝜈 +where G is the elastic shear modulus, v is the viscosity coefficient, and bold indicates a +tensor. The stress increment over one timestep dt is +𝑑𝜎 ′ = 2𝐺𝜺̇total𝑑𝑡 − +𝑑𝑡 σ′ +The stress before the update is used for σ′. For shell elements the through-thickness +strain rate is calculated as follows. +𝑑𝜎33 = 0 = 𝐾(𝜀̇11 + 𝜀̇22 + 𝜀̇33)𝑑𝑡 + 2𝐺𝜀′̇ +33𝑑𝑡 − +𝑑𝑡𝜎′33 +where the subscript ij = 33 denotes the through-thickness direction and K is the elastic +bulk modulus. This leads to: +𝐺) +𝑎 = +𝜀̇33 = −𝑎(𝜀̇11 + 𝜀̇22) + 𝑏𝑝 +(𝐾 − 2 +(𝐾 + 4 +𝐺𝑑𝑡 +𝜐(𝐾 + 4 +𝑏 = +𝐺) +𝐺) +in which p is the pressure defined as the negative of the hydrostatic stress. +The variation of viscosity with temperature can be defined in any one of the 3 ways. +(i) +Constant, V = V0 Do not define constants, A, B, and C or the piecewise +curve.(leave card 4 blank) +(ii) +V = V0 × 10 +(A/(T-B) + C) +(iii) +Piecewise curve: define the variation of viscosity with temperature. +NOTE: Viscosity is inactive during dynamic re- +laxation. +*MAT_ELASTIC_WITH_VISCOSITY_CURVE +This is Material Type 60 which was developed to simulate forming of glass products +(e.g., car windshields) at high temperatures. Deformation is by viscous flow but elastic +deformations can also be large. The material model, in which the viscosity may vary +with temperature, is suitable for treating a wide range of viscous flow problems and is +implemented for brick and shell elements. Load curves are used to represent the +temperature dependence of Poisson’s ratio, Young’s modulus, the coefficient of +expansion, and the viscosity. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +V0 +F +3 +4 +A +F +4 +5 +B +F +5 +6 +C +F +6 +7 +8 +LCID +F +7 +8 +Variable +PR_LC +YM_LC +A_LC +V_LC +V_LOG +Type +F +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +V0 +A +B +C +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Temperature independent dynamic viscosity coefficient, V0. If +defined, the temperature dependent viscosity defined below is +skipped, see type (i) and (ii) definitions for viscosity below. +Dynamic viscosity coefficient, see type (i) and (ii) definitions +below. +Dynamic viscosity coefficient, see type (i) and (ii) definitions +below. +Dynamic viscosity coefficient, see type (i) and (ii) definitions +below. +VARIABLE +DESCRIPTION +Load curve defining factor on dynamic +viscosity versus temperature, see type (iii). (Optional). +Load curve defining Poisson’s ratio as a +function of temperature. +Load curve defining Young’s modulus as +a function of temperature. +Load curve defining the coefficient of +thermal expansion as a function of temperature. +Load curve defining the dynamic +viscosity as a function of temperature. +Flag for the form of V_LC. If V_LOG = 1.0, the value specified in +V_LC is the natural logarithm of the viscosity, ln(V). The value +interpolated from the curve is then exponentiated to obtain the +viscosity. If V_LOG = 0.0, the value is the viscosity. The +logarithmic form is useful if the value of the viscosity changes by +orders of magnitude over the temperature range of the data. +LCID +PR_LC +YM_LC +A_LC +V_LC +V_LOG +Remarks: +Volumetric behavior is treated as linear elastic. The deviatoric strain rate is considered +to be the sum of elastic and viscous strain rates: +′ = ε̇elastic +ε̇total +′ +′ ++ ε̇viscous += +𝝈̇ ′ +2𝐺 ++ +σ′ +2𝜈 +where G is the elastic shear modulus, v is the viscosity coefficient, and bold~ indicates a +tensor. The stress increment over one timestep dt is +𝑑𝝈′ = 2𝐺ε̇total +′ + 𝑑𝑡 − + 𝑑𝑡 𝝈′ +The stress before the update is used for σ′. For shell elements the through-thickness +strain rate is calculated as follows. +𝑑𝜎33 = 0 = 𝐾(𝜀̇11 + 𝜀̇22 + 𝜀̇33)𝑑𝑡 + 2𝐺𝜀′̇ +33𝑑𝑡 − +𝑑𝑡𝜎′33 +where the subscript ij = 33 denotes the through-thickness direction and K is the elastic +bulk modulus. This leads to: +𝜀̇33 = −𝑎(𝜀̇11 + 𝜀̇22) + 𝑏𝑝 +𝑎 = +𝑏 = +𝐺) +𝐺) +(𝐾 − 2 +(𝐾 + 4 +𝐺𝑑𝑡 +𝜐(𝐾 + 4 +𝐺) +in which p is the pressure defined as the negative of the hydrostatic stress. +The variation of viscosity with temperature can be defined in any one of the 3 ways. +(i) +(ii) +(iii) +Constant, V = V0 Do not define constants, A, B, and C or the piecewise +curve.(leave card 4 blank) +V = V0 × 10(A/(T-B) + C) +Piecewise curve: define the variation of viscosity with temperature. +Note: Viscosity is inactive during dynamic relaxation. +*MAT_KELVIN-MAXWELL_VISCOELASTIC +This is Material Type 61. This material is a classical Kelvin-Maxwell model for +modeling viscoelastic bodies, e.g., foams. This model is valid for solid elements only. +See also notes below. + Card 1 +1 +Variable +MID +2 +RO +3 +BULK +Type +A8 +F +F +4 +G0 +F +5 +GI +F +6 +DC +F +7 +FO +F +8 +SO +F +Default +none +none +none +none +none +0.0 +0.0 +0.0 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +BULK +Bulk modulus (elastic) +G0 +GI +DC +FO +Short-time shear modulus, G0 +Long-time (infinite) shear modulus, G∞ +Maxwell decay constant, β[FO = 0.0] or +Kelvin relaxation constant, τ [FO = 1.0] +Formulation option: +EQ.0.0: Maxwell, +EQ.1.0: Kelvin. +VARIABLE +SO +DESCRIPTION +Strain (logarithmic) output option to control what is written as +component 7 to the d3plot database. (LS-PrePost always blindly +labels this component as effective plastic strain.) The maximum +values are updated for each element each time step: +EQ.0.0: maximum principal strain that occurs during the +calculation, +EQ.1.0: maximum magnitude of the principal strain values that +occurs during the calculation, +EQ.2.0: maximum effective strain that occurs during the +calculation. +Remarks: +The shear relaxation behavior is described for the Maxwell model by: +A Jaumann rate formulation is used +𝐺(𝑡) = 𝐺 + (𝐺0 − 𝐺∞)𝑒−𝛽𝑡 +∇ +′ = 2 ∫ 𝐺(𝑡 − 𝜏) 𝐷′𝑖𝑗(𝜏)𝑑𝑡 +ij + 𝑡 + 0 +∇ +𝑖𝑗, and the strain rate Dij . +where the prime denotes the deviatoric part of the stress rate, 𝜎 +For the Kelvin model the stress evolution equation is defined as: +𝑠 ̇𝑖𝑗 + +𝑠𝑖𝑗 = (1 + 𝛿𝑖𝑗)𝐺0𝑒 ̇𝑖𝑗 + (1 + 𝛿𝑖𝑗) +𝐺∞ +𝑒 ̇𝑖𝑗 +The strain data as written to the LS-DYNA database may be used to predict damage, see +[Bandak 1991]. +*MAT_VISCOUS_FOAM +This is Material Type 62. It was written to represent the Confor Foam on the ribs of +EuroSID side impact dummy. It is only valid for solid elements, mainly under +compressive loading. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E1 +F +4 +N1 +F +5 +V2 +F +6 +E2 +F +7 +N2 +F +8 +PR +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Initial Young’s modulus (E1) +Exponent in power law for Young’s modulus (n1) +Viscous coefficient (V2) +Elastic modulus for viscosity (E2), see notes below. +Exponent in power law for viscosity (n2) +Poisson’s ratio, ν +RO +E1 +N1 +V2 +E2 +N2 +PR +Remarks: +The model consists of a nonlinear elastic stiffness in parallel with a viscous damper. +The elastic stiffness is intended to limit total crush while the viscosity absorbs energy. +The stiffness E2 exists to prevent timestep problems. It is used for time step calculations +𝑡 is smaller than E2. It has to be carefully chosen to take into account the +a long as 𝐸1 +stiffening effects of the viscosity. Both E1 and V2 are nonlinear with crush as follows: +𝑡 = 𝐸1(𝑉−𝑛1) +𝐸1 +𝑡 = 𝑉2|1 − 𝑉|𝑛2 +𝑉2 +where viscosity generates a shear stress given by +𝛾̇ is the engineering shear strain rate, and V is the relative volume defined by the ratio +of the current to initial volume. +𝜏 = 𝑉2𝛾̇ +Table showing typical values (units of N, mm, s): + Card 1 +1 +Variable +MID +2 +RO +3 +E1 +4 +N1 +5 +V2 +6 +E2 +7 +N2 +8 +PR +Value +0.0036 +4.0 +0.0015 +100.0 +0.2 +0.05 +*MAT_CRUSHABLE_FOAM +This is Material Type 63 which is dedicated to modeling crushable foam with optional +damping and tension cutoff. Unloading is fully elastic. Tension is treated as elastic- +perfectly-plastic at the tension cut-off value. A modified version of this model, *MAT_- +MODIFIED_CRUSHABLE_FOAM includes strain rate effects. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +6 +7 +8 +LCID +TSC +DAMP +F +F +F +Default +none +none +none +none +none +0.0 +0.10 + VARIABLE +DESCRIPTION +MID +RO +E +PR +LCID +TSC +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus +Poisson’s ratio +Load curve ID defining yield stress versus volumetric strain, 𝛾, +see Figure M63-1. +Tensile stress cutoff. A nonzero, positive value is strongly +recommended for realistic behavior. +DAMP +Rate sensitivity via damping coefficient (.05 < recommended +value < .50). +Stress increases at +higher strain rates +Volumetric Strain +Figure M63-1. Behavior of strain rate sensitive crushable foam. Unloading is +elastic to the tension cutoff. Subsequent reloading follows the unloading +curve +Remarks: +The volumetric strain is defined in terms of the relative volume, V, as: +𝛾 = 1 − 𝑉 +The relative volume is defined as the ratio of the current to the initial volume. In place +of the effective plastic strain in the d3plot database, the integrated volumetric strain +(natural logarithm of the relative volume) is output. +*MAT_RATE_SENSITIVE_POWERLAW_PLASTICITY +This is Material Type 64 which will model strain rate sensitive elasto-plastic material +with a power law hardening. Optionally, the coefficients can be defined as functions of +the effective plastic strain. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +K +F +6 +M +F +7 +N +F +8 +E0 +F +Default +none +none +none +none +none +0.0001 +none +0.0002 + Card 2 +Variable +1 +VP +2 +3 +4 +5 +6 +7 +8 +EPS0 +Type +F +F +Default +0.0 +1.0 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +E +PR +K +M +Mass density +Young’s modulus of elasticity +Poisson’s ratio +Material constant, k. If k < 0 the absolute value of k is taken as +the load curve number that defines k as a function of effective +plastic strain. +Strain hardening coefficient, m. If m < 0 the absolute value of m +is taken as the load curve number that defines m as a function of +effective plastic strain. +VARIABLE +DESCRIPTION +N +E0 +VP +Strain rate sensitivity coefficient, n. If n < 0 the absolute value of +n is taken as the load curve number that defines n as a function of +effective plastic strain. +Initial strain rate (default = 0.0002) +Formulation for rate effects: +EQ.0.0: Scale yield stress (default) +EQ.1.0: Viscoplastic formulation +EPS0 +Quasi-static threshold strain rate. See description under *MAT_- +015. +Remarks: +This material model follows a constitutive relationship of the form: +𝜎 = 𝑘𝜀𝑚𝜀̇𝑛 +where 𝜎 is the yield stress, 𝜀 is the effective plastic strain, 𝜀̇ is the effective total strain +rate (VP = 0), respectively the effective plastic strain rate (VP = 1), and the constants k, +m, and n can be expressed as functions of effective plastic strain or can be constant with +respect to the plastic strain. The case of no strain hardening can be obtained by setting +the exponent of the plastic strain equal to a very small positive value, i.e. 0.0001. +This model can be combined with the superplastic forming input to control the +magnitude of the pressure in the pressure boundary conditions in order to limit the +effective plastic strain rate so that it does not exceed a maximum value at any +integration point within the model. +A fully viscoplastic formulation is optional. An additional cost is incurred but the +improvement is results can be dramatic. +*MAT_MODIFIED_ZERILLI_ARMSTRONG +This is Material Type 65 which is a rate and temperature sensitive plasticity model +which is sometimes preferred in ordnance design calculations. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F + Card 2 +Variable +1 +C1 +Type +F + Card 3 +Variable +1 +B1 +Type +F +2 +C2 +F +2 +B2 +F +3 +G +F +3 +C3 +F +3 +B3 +F +4 +E0 +F +4 +C4 +F +4 +G1 +F +5 +N +F +5 +C5 +F +5 +G2 +F +6 +7 +8 +TROOM +PC +SPALL +F +6 +C6 +F +6 +G3 +F +F +8 +VP +F +8 +BULK +F +7 +EFAIL +F +7 +G4 +F + VARIABLE +DESCRIPTION +MID +RO +G +E0 +N +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Shear modulus +𝜀̇0, factor to normalize strain rate +n, exponent for bcc metal +TROOM +Tr, room temperature +PC +pc, Pressure cutoff +VARIABLE +DESCRIPTION +SPALL +Spall Type: +EQ.1.0: minimum pressure limit, +EQ.2.0: maximum principal stress, +EQ.3.0: minimum pressure cutoff. +C1, coefficients for flow stress, see notes below. +C2, coefficients for flow stress, see notes below. +C3, coefficients for flow stress, see notes below. +C4, coefficients for flow stress, see notes below. +C5, coefficients for flow stress, see notes below. +C6, coefficients for flow stress, see notes below. +C1 +C2 +C3 +C4 +C5 +C6 +EFAIL +Failure strain for erosion +VP +Formulation for rate effects: +EQ.0.0: Scale yield stress (default) +EQ.1.0: Viscoplastic formulation +B1 +B2 +B3 +G1 +G2 +G3 +G4 +B1, coefficients +dependency of flow stress yield. +for polynomial +to represent +temperature +B2 +B3 +G1, coefficients for defining heat capacity and temperature +dependency of heat capacity. +G2 +G3 +G4 +BULK +Bulk modulus defined for shell elements only. Do not input for +solid elements. +*MAT_MODIFIED_ZERILLI_ARMSTRONG +The Armstrong-Zerilli Material Model expresses the flow stress as follows. +For fcc metals (n = 0), +𝜎 = 𝐶1 + {𝐶2(𝜀𝑝) +2⁄ [𝑒[−𝐶3+𝐶4ln(𝜀̇∗)]𝑇] + 𝐶5} [ +𝜇(𝑇) +𝜇(293) +] +where, +𝜀𝑝 = effective plastic strain +𝜀̇∗ = effective plastic strain rate += +𝜀̇ +𝜀̇0 +and 𝜀̇0 = 1, 1e-3, 1e-6 for time units of seconds, milliseconds, and microseconds, +respectively. +For bcc metals (n > 0), +𝜎 = 𝐶1 + 𝐶2𝑒[−𝐶3+𝐶4ln(𝜀̇∗)]𝑇 + [𝐶5(𝜀𝑝)𝑛 + 𝐶6] [ +𝜇(𝑇) +𝜇(293) +] +where +𝜇(𝑇) +𝜇(293) += 𝐵1 + 𝐵2𝑇 + 𝐵3𝑇2. +The relationship between heat capacity (specific heat) and temperature may be +characterized by a cubic polynomial equation as follows: +𝐶𝑝 = 𝐺1 + 𝐺2𝑇 + 𝐺3𝑇2 + 𝐺4𝑇3 +A fully viscoplastic formulation is optional. An additional cost is incurred but the +improvement is results can be dramatic. +*MAT_LINEAR_ELASTIC_DISCRETE_BEAM +This is Material Type 66. This material model is defined for simulating the effects of a +linear elastic beam by using six springs each acting about one of the six local degrees-of- +freedom. The two nodes defining a beam may be coincident to give a zero length beam, +or offset to give a finite length beam. For finite length discrete beams the absolute +value of the variable SCOOR in the SECTION_BEAM input should be set to a value of +2.0, which causes the local r-axis to be aligned along the two nodes of the beam to give +physically correct behavior. The distance between the nodes of a beam should not +affect the behavior of this model. A triad is used to orient the beam for the directional +springs. Translational/rotational stiffness and viscous damping effects are considered +for a local cartesian system, see notes below. Applications for this element include the +modeling of joint stiffnesses. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +4 +5 +6 +7 +8 +TKR +TKS +TKT +RKR +RKS +RKT +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +TDR +TDS +TDT +RDR +RDS +RDT +Type +F + Card 3 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +7 +8 +Variable +FOR +FOS +FOT +MOR +MOS +MOT +Type +F +F +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density, see also “volume” in the *SECTION_BEAM +definition. +*MAT_LINEAR_ELASTIC_DISCRETE_BEAM +DESCRIPTION +TKR +TKS +TKT +RKR +RKS +RKT +TDR +TDS +TDT +RDR +RDS +RDT +FOR +FOS +FOT +MOR +MOS +MOT +Translational stiffness along local r-axis, see notes below. +Translational stiffness along local s-axis. +Translational stiffness along local t-axis. +Rotational stiffness about the local r-axis. +Rotational stiffness about the local s-axis. +Rotational stiffness about the local t-axis. +Translational viscous damper along local r-axis. (Optional) +Translational viscous damper along local s-axis. (Optional) +Translational viscous damper along local t-axis. (Optional) +Rotational viscous damper about the local r-axis. (Optional) +Rotational viscous damper about the local s-axis. (Optional) +Rotational viscous damper about the local t-axis. (Optional) +Preload force in r-direction. (Optional) +Preload force in s-direction. (Optional) +Preload force in t-direction. (Optional) +Preload moment about r-axis. (Optional) +Preload moment about s-axis. (Optional) +Preload moment about t-axis. (Optional) +Remarks: +The formulation of the discrete beam (type 6) assumes that the beam is of zero length +and requires no orientation node. A small distance between the nodes joined by the +beam is permitted. The local coordinate system which determines (r,s,t) is given by the +coordinate ID, see *DEFINE_COORDINATE_OPTION, in the cross sectional input, see +*SECTION_BEAM, where the global system is the default. The local coordinate system +axes can rotate with either node of the beam or an average rotation of both nodes . +For null stiffness coefficients, no forces corresponding to these null values will develop. +The viscous damping coefficients are optional. +*MAT_NONLINEAR_ELASTIC_DISCRETE_BEAM +This is Material Type 67. This material model is defined for simulating the effects of +nonlinear elastic and nonlinear viscous beams by using six springs each acting about +one of the six local degrees-of-freedom. The two nodes defining a beam may be +coincident to give a zero length beam, or offset to give a finite length beam. For finite +length discrete beams the absolute value of the variable SCOOR in the SECTION_- +BEAM input should be set to a value of 2.0, which causes the local r-axis to be aligned +along the two nodes of the beam to give physically correct behavior. The distance +between the nodes of a beam should not affect the behavior of this material model. A +triad is used to orient the beam for the directional springs. Arbitrary curves to model +transitional/ rotational stiffness and damping effects are allowed. See notes below. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +RO +LCIDTR +LCIDTS +LCIDTT +LCIDRR +LCIDRS +LCIDRT +Type +A8 + Card 2 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +LCIDTDR LCIDTDS LCIDTDT LCIDRDR LCIDRDS LCIDRDT +Type +F + Card 3 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +7 +8 +Variable +FOR +FOS +FOT +MOR +MOS +MOT +Type +F +F +F +F +F +Optional Failure Cards. Cards 4 and 5 must be defined to consider failure; otherwise, +they are optional. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FFAILR +FFAILS +FFAILT MFAILR MFAILS MFAILT +Type +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +UFAILR +UFAILS +UFAILT +TFAILR +TFAILS +TFAILT +Type +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density, see also volume in *SECTION_BEAM definition. +LCIDTR +LCIDTS +LCIDTT +LCIDRR +LCIDRS +Load curve ID defining translational force resultant along local r- +axis versus relative translational displacement, see Remarks and +Figure M67-1. +Load curve ID defining translational force resultant along local s- +axis versus relative translational displacement. +Load curve ID defining translational force resultant along local t- +axis versus relative translational displacement. +Load curve ID defining rotational moment resultant about local r- +axis versus relative rotational displacement. +Load curve ID defining rotational moment resultant about local s- +axis versus relative rotational displacement. +LCIDRT +LCIDTDR +LCIDTDS +LCIDTDT +LCIDRDR +LCIDRDS +LCIDRDT +FOR +FOS +FOT +MOR +MOS +MOT +FFAILR +FFAILS +FFAILT +MFAILR +*MAT_NONLINEAR_ELASTIC_DISCRETE_BEAM +DESCRIPTION +Load curve ID defining rotational moment resultant about local t- +axis versus relative rotational displacement. +Load curve ID defining translational damping force resultant +along local r-axis versus relative translational velocity. +Load curve ID defining translational damping force resultant +along local s-axis versus relative translational velocity. +Load curve ID defining translational damping force resultant +along local t-axis versus relative translational velocity. +Load curve ID defining rotational damping moment resultant +about local r-axis versus relative rotational velocity. +Load curve ID defining rotational damping moment resultant +about local s-axis versus relative rotational velocity. +Load curve ID defining rotational damping moment resultant +about local t-axis versus relative rotational velocity. +Preload force in r-direction. (Optional) +Preload force in s-direction. (Optional) +Preload force in t-direction. (Optional) +Preload moment about r-axis. (Optional) +Preload moment about s-axis. (Optional) +Preload moment about t-axis. (Optional) +Optional failure parameter. If zero, the corresponding force, Fr, is +not considered in the failure calculation. +Optional failure parameter. If zero, the corresponding force, Fs, is +not considered in the failure calculation. +Optional failure parameter. If zero, the corresponding force, Ft, is +not considered in the failure calculation. +Optional failure parameter. If zero, the corresponding moment, +Mr, is not considered in the failure calculation. +DESCRIPTION +Optional failure parameter. If zero, the corresponding moment, +Ms, is not considered in the failure calculation. +Optional failure parameter. If zero, the corresponding moment, +Mt, is not considered in the failure calculation. +Optional +displacement, ur, is not considered in the failure calculation. +failure parameter. +If zero, +the corresponding +Optional +displacement, us, is not considered in the failure calculation. +failure parameter. +If zero, +the corresponding +Optional +displacement, ut, is not considered in the failure calculation. +failure parameter. +If zero, +the corresponding +Optional failure parameter. If zero, the corresponding rotation, +θr, is not considered in the failure calculation. +Optional failure parameter. If zero, the corresponding rotation, +θs, is not considered in the failure calculation. +Optional failure parameter. If zero, the corresponding rotation, +θt, is not considered in the failure calculation. + VARIABLE +MFAILS +MFAILT +UFAILR +UFAILS +UFAILT +TFAILR +TFAILS +TFAILT +Remarks: +For null load curve ID’s, no forces are computed. +The formulation of the discrete beam (type 6) assumes that the beam is of zero length +and requires no orientation node. A small distance between the nodes joined by the +beam is permitted. The local coordinate system which determines (r,s,t) is given by the +coordinate ID, see *DEFINE_COORDINATE_OPTION, in the cross sectional input, see +*SECTION_BEAM, where the global system is the default. The local coordinate system +axes can rotate with either node of the beam or an average rotation of both nodes . +If different behavior in tension and compression is desired in the calculation of the force +resultants, the load curve(s) must be defined in the negative quadrant starting with the +most negative displacement then increasing monotonically to the most positive. If the +load curve behaves similarly in tension and compression, define only the positive +quadrant. Whenever displacement values fall outside of the defined range, the +resultant forces will be extrapolated. Figure M67-1 depicts a typical load curve for a +force resultant. Load curves used for determining the damping forces and moment +resultants always act identically in tension and compression, since only the positive +quadrant values are considered, i.e., start the load curve at the origin [0,0]. +(a.) +DISPLACEMENT +(b.) +Figure M67-1. The resultant forces and moments are determined by a table +lookup. If the origin of the load curve is at [0,0] as in (b.) and tension and +compression responses are symmetric. +| +DISPLACEMENT +| +Catastrophic failure based on force resultants occurs if the following inequality is +satisfied. +( +𝐹𝑟 +fail +𝐹𝑟 +) ++ ( +𝐹𝑠 +fail +𝐹𝑠 +) ++ ( +𝐹𝑡 +fail +𝐹𝑡 +) ++ ( +𝑀𝑟 +fail +𝑀𝑟 +) ++ ( +𝑀𝑠 +fail +𝑀𝑠 +) ++ ( +𝑀𝑡 +fail +𝑀𝑡 +) +− 1. ≥ 0. +After failure the discrete element is deleted. Likewise, catastrophic failure based on +displacement resultants occurs if the following inequality is satisfied: +( +𝑢𝑟 +fail +𝑢𝑟 +) ++ ( +𝑢𝑠 +fail +𝑢𝑠 +) ++ ( +𝑢𝑡 +fail +𝑢𝑡 +) ++ ( +) +𝜃𝑟 +fail +𝜃𝑟 ++ ( +𝜃𝑠 +fail +𝜃𝑠 +) ++ ( +𝜃𝑡 +fail +𝜃𝑡 +) +− 1. ≥ 0. +After failure the discrete element is deleted. If failure is included either one or both of +the criteria may be used. +*MAT_NONLINEAR_PLASTIC_DISCRETE_BEAM +This is Material Type 68. This material model is defined for simulating the effects of +nonlinear elastoplastic, linear viscous behavior of beams by using six springs each +acting about one of the six local degrees-of-freedom. The two nodes defining a beam +may be coincident to give a zero length beam, or offset to give a finite length beam. For +finite length discrete beams the absolute value of the variable SCOOR in the SEC- +TION_BEAM input should be set to a value of 2.0, which causes the local r-axis to be +aligned along the two nodes of the beam to give physically correct behavior. The +distance between the nodes of a beam should not affect the behavior of this material +model. A triad is used to orient the beam for the directional springs. Translation- +al/rotational stiffness and damping effects can be considered. The plastic behavior is +modeled using force/moment curves versus displacements/rotation. Optionally, +failure can be specified based on a force/moment criterion and a displacement rotation +criterion. See also notes below. + Card 1 +1 +Variable +MID +2 +RO +3 +4 +5 +6 +7 +8 +TKR +TKS +TKT +RKR +RKS +RKT +Type +A8 +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TDR +TDS +TDT +RDR +RDS +RDT +Type +F +F +F +F +F +F +Default +none +none +none +none +none +none +Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCPDR +LCPDS +LCPDT +LCPMR +LCPMS +LCPMT +Type +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FFAILR +FFAILS +FFAILT MFAILR MFAILS MFAILT +Type +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +UFAILR +UFAILS +UFAILT +TFAILR +TFAILS +TFAILT +Type +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FOR +FOS +FOT +MOR +MOS +MOT +Type +F +F +F +F +F +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density, see also volume on *SECTION_BEAM definition. +VARIABLE +DESCRIPTION +TKR +TKS +TKT +RKR +RKS +RKT +TDR +TDS +TDT +RDR +RDS +RDT +LCPDR +LCPDS +LCPDT +LCPMR +LCPMS +Translational stiffness along local r-axis +Translational stiffness along local s-axis +Translational stiffness along local t-axis +Rotational stiffness about the local r-axis +Rotational stiffness about the local s-axis +Rotational stiffness about the local t-axis +Translational viscous damper along local r-axis +Translational viscous damper along local s-axis +Translational viscous damper along local t-axis +Rotational viscous damper about the local r-axis +Rotational viscous damper about the local s-axis +Rotational viscous damper about the local t-axis +Load curve ID-yield force versus plastic displacement r-axis. If +the curve ID is zero, and if TKR is nonzero, then elastic behavior +is obtained for this component. +Load curve ID-yield force versus plastic displacement s-axis. If +the curve ID is zero, and if TKS is nonzero, then elastic behavior is +obtained for this component. +Load curve ID-yield force versus plastic displacement t-axis. If +the curve ID is zero, and if TKT is nonzero, then elastic behavior +is obtained for this component. +Load curve ID-yield moment versus plastic rotation r-axis. If the +curve ID is zero, and if RKR is nonzero, then elastic behavior is +obtained for this component. +Load curve ID-yield moment versus plastic rotation s-axis. If the +curve ID is zero, and if RKS is nonzero, then elastic behavior is +obtained for this component. +LCPMT +FFAILR +FFAILS +FFAILT +MFAILR +MFAILS +MFAILT +UFAILR +UFAILS +UFAILT +TFAILR +TFAILS +TFAILT +FOR +FOS +*MAT_NONLINEAR_PLASTIC_DISCRETE_BEAM +DESCRIPTION +Load curve ID-yield moment versus plastic rotation t-axis. If the +curve ID is zero, and if RKT is nonzero, then elastic behavior is +obtained for this component. +Optional failure parameter. If zero, the corresponding force, Fr, is +not considered in the failure calculation. +Optional failure parameter. If zero, the corresponding force, Fs, is +not considered in the failure calculation. +Optional failure parameter. If zero, the corresponding force, Ft, is +not considered in the failure calculation. +Optional failure parameter. If zero, the corresponding moment, +Mr, is not considered in the failure calculation. +Optional failure parameter. If zero, the corresponding moment, +Ms, is not considered in the failure calculation. +Optional failure parameter. If zero, the corresponding moment, +Mt, is not considered in the failure calculation. +Optional +displacement, ur, is not considered in the failure calculation. +failure parameter. +If zero, +the corresponding +Optional +displacement, us, is not considered in the failure calculation. +failure parameter. +If zero, +the corresponding +Optional +displacement, ut, is not considered in the failure calculation. +failure parameter. +If zero, +the corresponding +Optional failure parameter. If zero, the corresponding rotation, +θr, is not considered in the failure calculation. +Optional failure parameter. If zero, the corresponding rotation, +θs, is not considered in the failure calculation. +Optional failure parameter. If zero, the corresponding rotation, +θt, is not considered in the failure calculation. +Preload force in r-direction. (Optional) +Preload force in s-direction. (Optional) +VARIABLE +DESCRIPTION +Preload force in t-direction. (Optional) +Preload moment about r-axis. (Optional) +Preload moment about s-axis. (Optional) +Preload moment about t-axis. (Optional) +FOT +MOR +MOS +MOT +Remarks: +For the translational and rotational degrees of freedom where elastic behavior is +desired, set the load curve ID to zero. +The plastic displacement for the load curves is defined as: +plastic displacement = total displacement − yield force/elastic stiffness +The formulation of the discrete beam (type 6) assumes that the beam is of zero length +and requires no orientation node. A small distance between the nodes joined by the +beam is permitted. The local coordinate system which determines (r,s,t) is given by the +coordinate ID in the cross sectional input, see +*SECTION_BEAM, where the global system is the default. The local coordinate system +axes can rotate with either node of the beam or an average rotation of both nodes . +Catastrophic failure based on force resultants occurs if the following inequality is +satisfied. +( +𝐹𝑟 +fail +𝐹𝑟 +) ++ ( +𝐹𝑠 +fail +𝐹𝑠 +) ++ ( +𝐹𝑡 +fail +𝐹𝑡 +) ++ ( +𝑀𝑟 +fail +𝑀𝑟 +) ++ ( +𝑀𝑠 +fail +𝑀𝑠 +) ++ ( +𝑀𝑡 +fail +𝑀𝑡 +) +− 1. ≥ 0. +After failure the discrete element is deleted. Likewise, catastrophic failure based on +displacement resultants occurs if the following inequality is satisfied: +( +𝑢𝑟 +fail +𝑢𝑟 +) ++ ( +𝑢𝑠 +fail +𝑢𝑠 +) ++ ( +𝑢𝑡 +fail +𝑢𝑡 +) ++ ( +) +𝜃𝑟 +fail +𝜃𝑟 ++ ( +𝜃𝑠 +fail +𝜃𝑠 +) ++ ( +𝜃𝑡 +fail +𝜃𝑡 +) +− 1. ≥ 0. +PLASTIC DISPLACEMENT +Figure M68-1. The resultant forces and moments are limited by the yield +definition. The initial yield point corresponds to a plastic displacement of +zero +After failure the discrete element is deleted. If failure is included either one or both of +the criteria may be used. +*MAT_SID_DAMPER_DISCRETE_BEAM +This is Material Type 69. The side impact dummy uses a damper that is not adequately +treated by the nonlinear force versus relative velocity curves since the force +characteristics are dependent on the displacement of the piston. See also notes below. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +Variable +1 +C3 +2 +RO +F +2 +3 +ST +F +3 +STF +RHOF +Type +F +F +F +4 +D +F +4 +C1 +F +5 +R +F +5 +C2 +F +6 +H +F +6 +7 +K +F +7 +LCIDF +LCIDD +F +F +8 +C +F +8 +S0 +F +Orifrice Cards. Include on card per orifice. Read in up to 15 orifice locations. Input is +terminated when a “*” card is found. On the first card below the optional input +parameters SF and DF may be specified. + Cards 3 +1 +2 +Variable +ORFLOC ORFRAD +Type +F +F +3 +SF +F +4 +DC +F +5 +6 +7 +8 + VARIABLE +MID +RO +ST +D +R +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density, see also volume on *SECTION_BEAM definition. +St, piston stroke. St must equal or exceed the length of the beam +element, see Figure M69-1 below. +d, piston diameter +R, default orifice radius +H +K +C +C3 +STF +*MAT_SID_DAMPER_DISCRETE_BEAM +DESCRIPTION +h, orifice controller position +K, damping constant +LT.0.0: |K| is the load curve number ID, see *DEFINE_- +CURVE, defining the damping coefficient as a function +of the absolute value of the relative velocity. +C, discharge coefficient +Coefficient for fluid inertia term +k, stiffness coefficient if piston bottoms out +RHOF +ρ𝑓𝑙𝑢𝑖𝑑, fluid density +C1 +C2 +LCIDF +LCIDD +C1, coefficient for linear velocity term +C2, coefficient for quadratic velocity term +Load curve number ID defining force versus piston displacement, +s, i.e., term 𝑓 (𝑠 + 𝑠0). Compressive behavior is defined in the +positive quadrant of the force displacement curve. Displacements +falling outside of the defined force displacement curve are +extrapolated. Care must be taken to ensure that extrapolated +values are reasonable. +Load curve number ID defining damping coefficient versus +piston displacement, s, i.e., 𝑔(𝑠 + 𝑠0). Displacements falling +outside the defined curve are extrapolated. Care must be taken to +ensure that extrapolated values are reasonable. +S0 +Initial displacement s0, typically set to zero. +displacement corresponds to compressive behavior. + A positive +ORFLOC +di, orifice location of ith orifice relative to the fixed end. +ORFRAD +ri, orifice radius of ith orifice, if zero the default radius is used. +SF +DC +Scale factor on calculated force. The default is set to 1.0 +c, linear viscous damping coefficient used after damper bottoms +out either in tension or compression. +Remarks: +As the damper moves, the fluid flows through the open orifices to provide the +necessary damping resistance. While moving as shown in Figure M69-1 the piston +gradually blocks off and effectively closes the orifices. The number of orifices and the +size of their opening control the damper resistance and performance. The damping +force is computed from, +𝐹 = SF × +{⎧ +⎩{⎨ +𝐾𝐴𝑝𝑉𝑝 +{⎧𝐶1 +⎩{⎨ +𝐴0 +𝑡 + 𝐶2∣𝑉𝑝∣𝜌fluid +𝐴𝑝 +𝐶𝐴0 +𝑡 ) +⎡( +⎢ +⎣ +− 1 +}⎫ +⎤ +⎥ +⎭}⎬ +⎦ +}⎫ +− 𝑓 (𝑠 + 𝑠0) + 𝑉𝑝𝑔(𝑠 + 𝑠0) +⎭}⎬ +where K is a user defined constant or a tabulated function of the absolute value of the +relative velocity, Vp is the piston velocity, C is the discharge coefficient, Ap is the piston +𝑡 is the total open areas of orifices at time t, ρfluid is the fluid density, C1 is the +area, 𝐴0 +coefficient for the linear term, and C2 is the coefficient for the quadratic term. +d4 +d3 +d2 +d1 +Piston +Vp +ith Piston Orifice +Orifice Opening Controller +Figure M69-1. Mathematical model for the Side Impact Dummy damper. +2Ri - h +In the implementation, the orifices are assumed to be circular with partial covering by +the orifice controller. As the piston closes, the closure of the orifice is gradual. This +gradual closure is properly taken into account to insure a smooth response. If the +piston stroke is exceeded, the stiffness value, k, limits further movement, i.e., if the +damper bottoms out in tension or compression the damper forces are calculated by +replacing the damper by a bottoming out spring and damper, k and c, respectively. The +piston stroke must exceed the initial length of the beam element. The time step +calculation is based in part on the stiffness value of the bottoming out spring. A typical +force versus displacement curve at constant relative velocity is shown in Figure M69-2. +The factor, SF, which scales the force defaults to 1.0 and is analogous to the adjusting +ring on the damper. +Last orifice +closes. +Force increases as orifice +is gradually covered. +DISPLACEMENT +Figure M69-2. Force versus displacement as orifices are covered at a constant +relative velocity. Only the linear velocity term is active. +*MAT_HYDRAULIC_GAS_DAMPER_DISCRETE_BEAM +This is Material Type 70. This special purpose element represents a combined hydraulic +and gas-filled damper which has a variable orifice coefficient. A schematic of the +damper is shown in Figure M70-1. Dampers of this type are sometimes used on buffers +at the end of railroad tracks and as aircraft undercarriage shock absorbers. This +material can be used only as a discrete beam element. See also notes below. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F + Card 2 +1 +Variable +LCID +Type +F +2 +FR +F +3 +CO +F +3 +4 +N +F +4 +SCLF +CLEAR +F +F +5 +P0 +F +5 +6 +PA +F +6 +7 +AP +F +7 +8 +KH +F +8 + VARIABLE +MID +RO +CO +N +P0 +PA +AP +KH +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density, see also volume in *SECTION_BEAM definition. +Length of gas column, Co +Adiabatic constant +Initial gas pressure, P0 +Atmospheric pressure, Pa +Piston cross sectional area, Ap +Hydraulic constant, K +LCID +Load curve ID, see *DEFINE_CURVE, defining the orifice area, +a0, versus element deflection. +Orifice + VARIABLE +FR +Oil +Profiled Pin +Gas +Figure M70-1. Schematic of Hydraulic/Gas damper. +DESCRIPTION +Return factor on orifice force. This acts as a factor on the +hydraulic force only and is applied when unloading. It is +intended to represent a valve that opens when the piston unloads +to relieve hydraulic pressure. Set it to 1.0 for no such relief. +SCLF +Scale factor on force. (Default = 1.0) +CLEAR +Clearance (if nonzero, no tensile force develops for positive +displacements and negative forces develop only after the +clearance is closed. +Remarks: +As the damper is compressed two actions contribute to the force which develops. First, +the gas is adiabatically compressed into a smaller volume. Secondly, oil is forced +through an orifice. A profiled pin may occupy some of the cross-sectional area of the +orifice; thus, the orifice area available for the oil varies with the stroke. The force is +assumed proportional to the square of the velocity and inversely proportional to the +available area. +The equation for this element is: +𝐹 = SCLF × {𝐾ℎ ( +𝑎0 +) ++ [𝑃0 ( +𝐶0 +𝐶0 − 𝑆 +) +− 𝑃𝑎] 𝐴𝑝} +where S is the element deflection and V is the relative velocity across the element. +*MAT_071 +This is Material Type 71. This model permits elastic cables to be realistically modeled; +thus, no force will develop in compression. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +LCID +F +Default +none +none +none +none +5 +F0 +F +0 +6 +7 +8 +TMAXF0 +TRAMP +IREAD +F +0 +F +0 +I +0 +Additional card for IREAD > 1. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +OUTPUT +TSTART +FRACL0 MXEPS +MXFRC +Type +Default +I +0 +F +0 +F +0 +F +F +1.0E+20 1.0E+20 + VARIABLE +DESCRIPTION +MID +RO +E +LCID +F0 +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density, see also volume in *SECTION_BEAM definition. +GT.0.0: Young’s modulus +LT.0.0: Stiffness +Load curve ID, see *DEFINE_CURVE, defining the stress versus +engineering strain. (Optional). +Initial tensile force. If F0 is defined, an offset is not needed for an +initial tensile force. +TMAXF0 +Time for which pre-tension force will be held +*MAT_CABLE_DISCRETE_BEAM +DESCRIPTION +TRAMP +Ramp-up time for pre-tension force +IREAD +Set to 1 to read second line of input +OUTPUT +Flag = 1 to output axial strain +TSTART +Time at which the ramp-up of pre-tension begins +FRACL0 +Fraction of initial length that should be reached over time period +of TRAMP. Corresponding tensile force builds up as necessary to +reach cable length = FRACL0 × L0 at time t = TRAMP. +MXEPS +Maximum strain at failure +MXFRC +Maximum force at failure +Remarks: +The force, F, generated by the cable is nonzero if and only if the cable is tension. The +force is given by: +where ΔL is the change in length +𝐹 = max(𝐹0 + 𝐾Δ𝐿, 0. ) +Δ𝐿 = current length − (initial length − offset) +and the stiffness (E > 0.0 only ) is defined as: +𝐾 = +𝐸 × area +(initial length − offset) +Note that a constant force element can be obtained by setting: +although the application of such an element is unknown. +𝐹0 > 0 and 𝐾 = 0 +The area and offset are defined on either the cross section or element cards. For a slack +cable the offset should be input as a negative length. For an initial tensile force the +offset should be positive. +If a load curve is specified the Young’s modulus will be ignored and the load curve will +be used instead. The points on the load curve are defined as engineering stress versus +engineering strain, i.e., the change in length over the initial length. The unloading +behavior follows the loading. +By default, cable pretension is applied only at the start of the analysis. If the cable is +attached to flexible structure, deformation of the structure will result in relaxation of the +cables, which will therefore lose some or all of the intended preload. +This can be overcome by using TMAXF0. In this case, it is expected that the structure +will deform under the loading from the cables and that this deformation will take time +to occur during the analysis. The unstressed length of the cable will be continuously +adjusted until time TMAXF0 such that the force is maintained at the user-defined pre- +tension force – this is analogous to operation of the pre-tensioning screws in real cables. +After time TMAXF0, the unstressed length is fixed and the force in the cable is +determined in the normal way using the stiffness and change of length. +Sudden application of the cable forces at time zero may result in an excessively dynamic +response during pre-tensioning. A ramp-up time TRAMP may optionally be defined. +The cable force ramps up from zero at time TSTART to the full pre-tension F0 at time +TSTART + TRAMP. TMAXF0, if set less than TSTART + TRAMP by the user, will be +internally reset to TSTART + TRAMP. +If the model does not use dynamic relaxation, it is recommended that damping be +applied during pre-tensioning so that the structure reaches a steady state by time +TMAXF0. +If the model uses dynamic relaxation, TSTART, TRAMP, and TMAXF0 apply only +during dynamic relaxation. The cable preload at the end of dynamic relaxation carries +over to the start of the subsequent transient analysis. +The cable mass will be calculated from length × area × density if VOL is set to zero on +*SECTION_BEAM. Otherwise, VOL × density will be used. +If OUTPUT is set to 1, one additional history variable representing axial strain is output +to d3plot for the cable elements. This axial strain can be plotted by LS-PrePost by +selecting the beam component labeled as “axial stress”. Though the label says “axial +stress”, it is actually axial strain. +If the stress-strain load curve option, LCID, is combined with preload, two types of +behavior are available: +1. +2. +If the preload is applied using the TMAXF0/TRAMP method, the initial strain +is calculated from the stress-strain curve to achieve the desired preload. +If TMAXF0/TRAMP are not used, the preload force is taken as additional to the +force calculated from the stress/strain curve. Thus, the total stress in the cable +will be higher than indicated by the stress/strain curve. +*MAT_CONCRETE_DAMAGE +This is Material Type 72. This model has been used to analyze buried steel reinforced +concrete structures subjected to impulsive loadings. A newer version of this model is +available as *MAT_CONCRETE_DAMAGE_REL3 +4 +5 +6 +7 +8 + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +PR +F +Default +none +none +none +5 +6 +7 +8 + Card 2 +1 +Variable +SIGF +Type +F +2 +A0 +F +3 +A1 +F +4 +A2 +F +Default +0.0 +0.0 +0.0 +0.0 + Card 3 +1 +2 +3 +4 +5 +Variable +A0Y +A1Y +A2Y +A1F +A2F +Type +F +F +F +F +F +6 +B1 +F +7 +B2 +F +8 +B3 +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Card 4 +1 +Variable +PER +Type +F +2 +ER +F +3 +4 +5 +6 +7 +8 +PRR +SIGY +ETAN +LCP +LCR +F +F +F +F +F +Default +0.0 +0.0 +0.0 +none +0.0 +none +none + Card 5 +Variable +Type +1 +λ +F +2 +λ2 +F +3 +λ3 +F +4 +λ4 +F +5 +λ5 +F +6 +λ6 +F +7 +λ7 +F +8 +λ8 +F +Default +none +none +none +none +none +none +none +none + Card 6 +Variable +1 +λ9 +2 +3 +4 +5 +6 +7 +8 +λ10 +λ11 +λ12 +λ13 +Type +F +F +F +F +F +Default +none +none +none +none +none + Card 7 +Variable +1 +η1 +Type +F +2 +η2 +F +3 +η3 +F +4 +η4 +F +5 +η5 +F +6 +η6 +F +7 +η7 +F +8 +η8 +F +Default +none +none +none +none +none +none +none +none +Variable +1 +η9 +*MAT_CONCRETE_DAMAGE +2 +3 +4 +5 +6 +7 +8 +η10 +η11 +η12 +η13 +Type +F +F +F +F +F +Default +none +none +none +none +none + VARIABLE +DESCRIPTION +MID +RO +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Poisson’s ratio. +SIGF +Maximum principal stress for failure. +A0 +A1 +A2 +A0Y +A1Y +A2Y +A1F +A2F +B1 +B2 +B3 +PER +ER +Cohesion. +Pressure hardening coefficient. +Pressure hardening coefficient. +Cohesion for yield +Pressure hardening coefficient for yield limit +Pressure hardening coefficient for yield limit +Pressure hardening coefficient for failed material. +Pressure hardening coefficient for failed material. +Damage scaling factor. +Damage scaling factor for uniaxial tensile path. +Damage scaling factor for triaxial tensile path. +Percent reinforcement. +Elastic modulus for reinforcement. +VARIABLE +DESCRIPTION +PRR +SIGY +Poisson’s ratio for reinforcement. +Initial yield stress. +ETAN +Tangent modulus/plastic hardening modulus. +Load curve ID giving rate sensitivity for principal material, see +*DEFINE_CURVE. +Load curve ID giving rate sensitivity for reinforcement, see *DE- +FINE_CURVE. +Tabulated damage function +Tabulated scale factor. +LCP +LCR +λ1 - λ13 +η1 - η13 +Remarks: +1. Cohesion for failed material 𝑎0𝑓 = 0. +2. B3 must be positive or zero. +3. 𝜆𝑛 ≤ 𝜆𝑛+1. The first point must be zero. +*MAT_CONCRETE_DAMAGE_REL3 +This is Material Type 72R3. The Karagozian & Case (K&C) Concrete Model - Release III +is a three-invariant model, uses three shear failure surfaces, includes damage and +strain-rate effects, and has origins based on the Pseudo-TENSOR Model (Material Type +16). The most significant user improvement provided by Release III is a model +parameter generation capability, based solely on the unconfined compression strength +of the concrete. The implementation of Release III significantly changed the user input, +thus previous input files using Material Type 72, i.e. prior to LS-DYNA Version 971, are +not compatible with the present input format. +An open source reference, that precedes the parameter generation capability, is +provided in Malvar et al. [1997]. A workshop proceedings reference, Malvar et al. +[1996], is useful, but may be difficult to obtain. More recent, but limited distribution +reference materials, e.g. Malvar et al. [2000], may be obtained by contacting +Karagozian & Case. +Seven card images are required to define the complete set of model parameters for the +K&C Concrete Model. An Equation-of-State is also required for the pressure-volume +strain response. Brief descriptions of all the input parameters are provided below, +however it is expected that this model will be used primarily with the option to +automatically generate the model parameters based on the unconfined compression +strength of the concrete. These generated material parameters, along with the +generated parameters for *EOS_TABULATED_COMPACTION, are written to the +d3hsp file. +4 +5 +6 +7 +8 + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +PR +F +Default +none +none +none +Card 2 +Variable +1 +FT +Type +F +2 +A0 +F +3 +A1 +F +4 +A2 +F +5 +B1 +F +6 +7 +8 +OMEGA +A1F +F +F +Default +none +0.0 +0.0 +0.0 +0.0 +none +0.0 + Card 3 +Variable +1 +Sλ +2 +3 +4 +5 +6 +7 +8 +NOUT +EDROP +RSIZE +UCF +LCRATE +LOCWID +NPTS +Type +F +F +F +F +F +I +F +F +Default +none +none +none +none +none +none +none +none + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +λ01 +λ02 +λ03 +λ04 +λ05 +λ06 +λ07 +λ08 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none + Card 5 +1 +2 +3 +4 +5 +Variable +λ09 +λ10 +λ11 +λ12 +λ13 +Type +F +F +F +F +F +6 +B3 +F +7 +8 +A0Y +A1Y +F +F +Default +none +none +none +none +none +none +0.0 +0.0 +Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +η01 +η02 +η03 +η04 +η05 +η06 +η07 +η08 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none + Card 7 +1 +2 +3 +4 +5 +Variable +η09 +η10 +η11 +η12 +η13 +Type +F +F +F +F +F +6 +B2 +F +7 +8 +A2F +A2Y +F +F +Default +none +none +none +none +none +0.0 +0.0 +0.0 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +PR +FT +A0 +A1 +A2 +B1 +Mass density. +Poisson’s ratio, 𝜈. +Uniaxial tensile strength, 𝑓𝑡. +Maximum shear failure surface parameter, 𝑎0 or −𝑓𝑐 +parameter generation (recommended). +′ for +Maximum shear failure surface parameter, 𝑎1. +Maximum shear failure surface parameter, 𝑎2. +Compressive damage scaling parameter, 𝑏1 +OMEGA +Fractional dilatancy, 𝜔. +A1F +Sλ +2-392 (EOS) +Residual failure surface coefficient, 𝑎1𝑓 . +VARIABLE +DESCRIPTION +NOUT +Output selector for effective plastic strain . +EDROP +RSIZE +UCF +LCRATE +LOCWID +NPTS +λ01 +λ02 +λ03 +λ04 +λ05 +λ06 +λ07 +λ08 +λ09 +λ10 +λ11 +λ12 +Post peak dilatancy decay, 𝑁𝛼. +Unit conversion factor for length (inches/user-unit), e.g. 39.37 if +user length unit in meters. +Unit conversion factor for stress (psi/user-unit), e.g. 145 if 𝑓′𝑐 in +MPa. +Define (load) curve number for strain-rate effects; effective strain +rate on abscissa (negative = tension) and strength enhancement +on ordinate. If LCRATE is set to -1, strain rate effects are +automatically included, based on equations provided in Wu, +Crawford, Lan, and Magallanes [2014]. +Three times the maximum aggregate diameter (input in user +length units). +Number of points in 𝜆 versus 𝜂 damage relation; must be 13 +points. +1st value of damage function, (a.k.a., 1st value of “modified” +effective plastic strain; see references for details). +2nd value of damage function, +3rd value of damage function, +4th value of damage function, +5th value of damage function, +6th value of damage function, +7th value of damage function, +8th value of damage function, +9th value of damage function, +10th value of damage function, +11th value of damage function, +12th value of damage function, +VARIABLE +DESCRIPTION +λ13 +B3 +A0Y +A1Y +η01 +η02 +η03 +η04 +η05 +η06 +η07 +η08 +η09 +η10 +η11 +η12 +η13 +B2 +A2F +A2Y +13th value of damage function. +Damage scaling coefficient for triaxial tension, 𝑏3. +Initial yield surface cohesion, 𝑎0𝑦. +Initial yield surface coefficient, 𝑎1𝑦. +1st value of scale factor, +2nd value of scale factor, +3rd value of scale factor, +4th value of scale factor, +5th value of scale factor, +6th value of scale factor, +7th value of scale factor, +8th value of scale factor, +9th value of scale factor, +10th value of scale factor, +11th value of scale factor, +12th value of scale factor, +13th value of scale factor. +Tensile damage scaling exponent, 𝑏2. +Residual failure surface coefficient, 𝑎2𝑓 . +Initial yield surface coefficient, 𝑎2𝑦. +λ, sometimes referred to as “modified” effective plastic strain, is computed internally as +a function of effective plastic strain, strain rate enhancement factor, and pressure. η is a +function of λ as specified by the η vs. λ curve. The η value, which is always between 0 +and 1, is used to interpolate between the yield failure surface and the maximum failure +surface, or between the maximum failure surface and the residual failure surface, +depending on whether λ is to the left or right of the first peak in the the η vs. λ curve. +The “scaled damage measure” ranges from 0 to 1 as the material transitions from the +yield failure surface to the maximum failure surface, and thereafter ranges from 1 to 2 +as the material ranges from the maximum failure surface to the residual failure surface. +See the references for details. +Output of Selected Variables: +The quantity labeled as “plastic strain” by LS-PrePost is actually the quantity described +in Table M72-1, in accordance with the input value of NOUT . +NOUT +Function +Description +1 +2 +3 +4 +Current shear failure surface radius +𝛿 = 2𝜆/(𝜆 + 𝜆𝑚) +𝜎̇𝑖𝑗𝜀̇𝑖𝑗 +𝑝 +𝜎̇𝑖𝑗𝜀̇𝑖𝑗 +Scaled damage measure +Strain energy (rate) +Plastic strain energy (rate) +Table M72-1. Description of quantity labeled “plastic strain” by LS-PrePost. +An additional six extra history variables as shown in Table M72-2 may be be written by +setting NEIPH = 6 on the keyword *DATABASE_EXTENT_BINARY. The extra history +variables are labeled as "history var#1" through "history var#6" in LS-PrePost. +Label +Description +history var#1 +Internal energy +history var#2 +Pressure from bulk viscosity +history var#3 +Volume in previous time step +history var#4 +history var#5 +history var#6 +Plastic volumetric strain +Slope of damage evolution (η vs. λ) +curve +“Modified” effective plastic strain (λ) +Table M72-2. Extra History Variables for *MAT_072R3 +Sample Input for Concrete: +As an example of the K&C Concrete Model material parameter generation, the +following sample input for a 45.4 MPa (6,580 psi) unconfined compression strength +concrete is provided. The basic units for the provided parameters are length in +millimeters (mm), time in milliseconds (msec), and mass in grams (g). This base unit set +yields units of force in Newtons (N) and pressure in Mega-Pascals (MPa). +Card 1 +1 +Variable +MID +2 +RO +Type +72 +2.3E-3 + Card 2 +Variable +1 +FT +2 +A0 +Type +-45.4 +3 +PR +3 +A1 +4 +5 +6 +7 +8 +4 +A2 +5 +B1 +6 +7 +8 +OMEGA +A1F + Card 3 +Variable +1 +Sλ +2 +3 +4 +5 +6 +7 +8 +NOUT +EDROP +RSIZE +UCF +LCRATE +LOCWID +NPTS +Type +3.94E-2 +145.0 +723.0 + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +λ01 +λ02 +λ03 +λ04 +λ05 +λ06 +λ07 +λ08 +Type + Card 5 +1 +2 +3 +4 +5 +Variable +λ09 +λ10 +λ11 +λ12 +λ13 +6 +B3 +7 +8 +A0Y +A1Y +Type +Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +η01 +η02 +η03 +η04 +η05 +η06 +η07 +η08 +Type + Card 7 +1 +2 +3 +4 +5 +Variable +η09 +η10 +η11 +η12 +η13 +6 +B2 +7 +8 +A2F +A2Y +Type +Shear strength enhancement factor versus effective strain rate is given by a curve (*DE- +FINE_CURVE) with LCID 723. The sample input values, see Malvar & Ross [1998], are +given in Table M72-3. +Strain-Rate (1/ms) +Enhancement +-3.0E+01 +-3.0E-01 +-1.0E-01 +-3.0E-02 +-1.0E-02 +-3.0E-03 +-1.0E-03 +-1.0E-04 +-1.0E-05 +-1.0E-06 +-1.0E-07 +-1.0E-08 +0.0E+00 +3.0E-08 +1.0E-07 +1.0E-06 +1.0E-05 +1.0E-04 +1.0E-03 +3.0E-03 +1.0E-02 +3.0E-02 +1.0E-01 +3.0E-01 +3.0E+01 +9.70 +9.70 +6.72 +4.50 +3.12 +2.09 +1.45 +1.36 +1.28 +1.20 +1.13 +1.06 +1.00 +1.00 +1.03 +1.08 +1.14 +1.20 +1.26 +1.29 +1.33 +1.36 +2.04 +2.94 +2.94 +Table M72-3. Enhancement versus effective strain rate for 45.4 MPa +concrete (sample). When defining curve LCRATE, input negative (tensile) +values of effective strain rate first. The enhancement should be positive +and should be 1.0 at a strain rate of zero. +*MAT_LOW_DENSITY_VISCOUS_FOAM +This is Material Type 73 for Modeling Low Density Urethane Foam with high +compressibility and with rate sensitivity which can be characterized by a relaxation +curve. Its main applications are for seat cushions, padding on the Side Impact +Dummies (SID), bumpers, and interior foams. Optionally, a tension cut-off failure can +be defined. Also, see the notes below and the description of material 57: *MAT_LOW_- +DENSITY_FOAM. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +LCID +F +5 +TC +F +6 +HU +F +7 +8 +BETA +DAMP +F +F +Default +Remarks +1.E+20 +1. +0.05 +3 +6 +1 +7 +8 + Card 2 +1 +2 +3 +4 +5 +Variable +SHAPE +FAIL +BVFLAG +KCON +LCID2 +BSTART +TRAMP +NV +Type +F +F +F +F +Default +1.0 +0.0 +0.0 +0.0 +F +0 +F +F +0.0 +0.0 +I +6 +Relaxation Constant Cards. If LCID2 = 0 then include the following viscoelastic +constants. Up to 6 cards may be input. A keyword card (with a “*” in column 1) +terminates this input if less than 6 cards are used. + Card 3 +Variable +Type +1 +GI +F +2 +3 +4 +5 +6 +7 +8 +BETAI +REF +F +Frequency Dependence Card. If LCID2 = -1 then include the following frequency +dependent viscoelastic data. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCID3 +LCID4 +SCALEW +SCALEA +Type +I +I +I +I + VARIABLE +DESCRIPTION +MID +RO +E +LCID +TC +HU +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus used in tension. For implicit problems E is set +to the initial slope of load curve LCID. +Load curve ID, see *DEFINE_CURVE, for nominal stress versus +strain. +Tension cut-off stress +Hysteretic unloading factor between 0 and 1 (default = 1, i.e., no +energy dissipation), see also Figure M57-1 +BETA +β, decay constant to model creep in unloading. +EQ.0.0: No relaxation. +DAMP +Viscous coefficient (.05 < recommended value <.50) to model +damping effects. +LT.0.0: |DAMP| is the load curve ID, which defines the +damping constant as a function of the maximum strain +in compression defined as: 𝜀max = max(1 − 𝜆1, 1 − +𝜆2, 1. −𝜆3) +In tension, the damping constant is set to the value corre- +sponding to the strain at 0. The abscissa should be defined +from 0 to 1. +SHAPE +Shape factor for unloading. Active for nonzero values of the +hysteretic unloading factor. Values less than one reduces the +energy dissipation and greater than one increases dissipation, see +also Figure M57-1. +VARIABLE +DESCRIPTION +FAIL +Failure option after cutoff stress is reached: +EQ.0.0: tensile stress remains at cut-off value, +EQ.1.0: tensile stress is reset to zero. +BVFLAG +Bulk viscosity activation flag, see remark below: +EQ.0.0: no bulk viscosity (recommended), +EQ.1.0: bulk viscosity active. +KCON +LCID2 +BSTART +Stiffness coefficient for contact interface stiffness. Maximum +slope in stress vs. strain curve is used. When the maximum slope +is taken for the contact, the time step size for this material is +reduced for stability. In some cases Δt may be significantly +smaller, and defining a reasonable stiffness is recommended. +Load curve ID of relaxation curve. If constants 𝛽𝑡 are determined +via a least squares fit. This relaxation curve is shown in Figure +M76-1. This model ignores the constant stress. +Fit parameter. In the fit, 𝛽1 is set to zero, 𝛽2 is set to BSTART, 𝛽3 +is 10 times 𝛽2, 𝛽4 is 10 times greater than 𝛽3 , and so on. If zero, +BSTART = .01. +TRAMP +Optional ramp time for loading. +NV +Number of terms in fit. If zero, the default is 6. Currently, the +maximum number is set to 6. Values of 2 are 3 are recommended, +since each term used adds significantly to the cost. Caution +should be exercised when taking the results from the fit. +Preferably, all generated coefficients should be positive. Negative +values may lead to unstable results. Once a satisfactory fit has +been achieved it is recommended that the coefficients which are +written into the output file be input in future runs. +Gi +Optional shear relaxation modulus for the ith term +BETAi +Optional decay constant if ith term +REF +*MAT_LOW_DENSITY_VISCOUS_FOAM +DESCRIPTION +Use reference geometry to initialize the stress tensor. The +reference geometry is defined by the keyword:*INITIAL_FOAM_- +REFERENCE_GEOMETRY . +EQ.0.0: off, +EQ.1.0: on. +LCID3 +LCID4 +Load curve ID giving the magnitude of the shear modulus as a +function of the frequency. LCID3 must use the same frequencies +as LCID4. +Load curve ID giving the phase angle of the shear modulus as a +function of the frequency. LCID4 must use the same frequencies +as LCID3. +SCALEW +Flag for the form of the frequency data. +EQ.0.0: Frequency is in cycles per unit time. +EQ.1.0: Circular frequency. +SCALEA +Flag for the units of the phase angle. +EQ.0.0: Degrees. +EQ.1.0: Radians. +Material Formulation: +This viscoelastic foam model is available to model highly compressible viscous foams. +The hyperelastic formulation of this model follows that of Material 57. +Rate effects are accounted for through linear viscoelasticity by a convolution integral of +the form +𝜎𝑖𝑗 +𝑟 = ∫ 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) +∂𝜀𝑘𝑙 +∂𝜏 +𝑑𝜏 +where 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) is the relaxation function. The stress tensor, 𝜎𝑖𝑗 +determined from the foam, 𝜎𝑖𝑗 +summation of the two contributions: +𝑟 , augments the stresses +𝑓 ; consequently, the final stress, 𝜎𝑖𝑗, is taken as the +𝜎𝑖𝑗 = 𝜎𝑖𝑗 +𝑓 + 𝜎𝑖𝑗 +𝑟 . +Since we wish to include only simple rate effects, the relaxation function is represented +by up to six terms of the Prony series: +𝑔(𝑡) = 𝛼0 + ∑ 𝛼𝑚𝑒−𝛽𝑚𝑡 +𝑚=1 +This model is effectively a Maxwell fluid which consists of a dampers and springs in +series. The formulation is performed in the local system of principal stretches where +only the principal values of stress are computed and triaxial coupling is avoided. +Consequently, the one-dimensional nature of this foam material is unaffected by this +addition of rate effects. The addition of rate effects necessitates 42 additional history +variables per integration point. The cost and memory overhead of this model comes +primarily from the need to “remember” the local system of principal stretches and the +evaluation of the viscous stress components. +Frequency data can be fit to the Prony series. Using Fourier transforms the relationship +between the relaxation function and the frequency dependent data is +𝐺𝑠(𝜔) = 𝛼0 + ∑ +𝑚=1 +𝛼𝑚(𝜔/𝛽𝑚)2 +1 + (𝜔/𝛽𝑚)2 +𝐺ℓ(𝜔) = ∑ +𝑚=1 +𝛼𝑚𝜔/𝛽𝑚 +1 + 𝜔/𝛽𝑚 +where the storage modulus and loss modulus are defined in terms of the frequency +dependent magnitude G and phase angle 𝜙 given by load curves LCID3 and LCID4 +respectively, +𝐺𝑠(𝜔) = 𝐺(𝜔) cos[𝜙(𝜔)] , and +𝐺𝑙(𝜔) = 𝐺(𝜔) sin[𝜙(𝜔)] +Remarks: +When hysteretic unloading is used the reloading will follow the unloading curve if the +decay constant, β, is set to zero. If β is nonzero the decay to the original loading curve is +governed by the expression: +1 − 𝑒−𝛽𝑡 +The bulk viscosity, which generates a rate dependent pressure, may cause an +unexpected volumetric response and, consequently, it is optional with this model. +The hysteretic unloading factor results in the unloading curve to lie beneath the loading +curve as shown in Figure M57-1. This unloading provides energy dissipation which is +reasonable in certain kinds of foam. +*MAT_ELASTIC_SPRING_DISCRETE_BEAM +This is Material Type 74. This model permits elastic springs with damping to be +combined and represented with a discrete beam element type 6. Linear stiffness and +damping coefficients can be defined, and, for nonlinear behavior, a force versus +deflection and force versus rate curves can be used. Displacement based failure and an +initial force are optional. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +Variable +FLCID +HLCID +Type +F +F +3 +K +F +3 +C1 +F +4 +F0 +F +4 +C2 +F +5 +D +F +5 +6 +7 +8 +CDF +TDF +F +6 +F +7 +8 +DLE +GLCID +F +I + VARIABLE +DESCRIPTION +MID +RO +K +F0 +D +CDF +TDF +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density, see also volume in *SECTION_BEAM definition. +Stiffness coefficient. +Optional initial force. This option is inactive if this material is +referenced in a part referenced by material type *MAT_ELAS- +TIC_6DOF_SPRING +Viscous damping coefficient. +Compressive displacement at failure. Input as a positive number. +After failure, no forces are carried. This option does not apply to +zero length springs. +EQ.0.0: inactive. +Tensile displacement at failure. After failure, no forces are +carried. +VARIABLE +DESCRIPTION +FLCID +HLCID +C1 +C2 +Load curve ID, see *DEFINE_CURVE, defining force versus +deflection for nonlinear behavior. +Load curve ID, see *DEFINE_CURVE, defining force versus +relative velocity for nonlinear behavior (optional). If the origin of +the curve is at (0,0) the force magnitude is identical for a given +magnitude of the relative velocity, i.e., only the sign changes. +Damping coefficient for nonlinear behavior (optional). +Damping coefficient for nonlinear behavior (optional). +DLE +Factor to scale time units. The default is unity. +GLCID +Optional load curve ID, see *DEFINE_CURVE, defining a scale +factor versus deflection for load curve ID, HLCID. If zero, a scale +factor of unity is assumed. +Remarks: +If the linear spring stiffness is used, the force, F, is given by: +𝐹 = 𝐹0 + KΔ𝐿 + DΔ𝐿̇ +but if the load curve ID is specified, the force is then given by: +𝐹 = 𝐹0 + K𝑓 (Δ𝐿) {1 + C1 × Δ𝐿̇ + C2 × sgn(Δ𝐿̇)ln [max (1. , +Δ𝐿̇ +DLE +)]} + DΔ𝐿̇ ++ 𝑔(Δ𝐿)ℎ(Δ𝐿̇) +In these equations, Δ𝐿 is the change in length +Δ𝐿 = current length − initial length +The cross sectional area is defined on the section card for the discrete beam elements, +See *SECTION_BEAM. The square root of this area is used as the contact thickness +offset if these elements are included in the contact treatment. +*MAT_BILKHU/DUBOIS_FOAM +This is Material Type 75. This model is for the simulation of isotropic crushable foams. +Uniaxial and triaxial test data are used to describe the behavior. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +4 +5 +YM +LCPY +LCUYS +F +3 +F +4 +F +5 +6 +VC +F +6 +7 +PC +F +8 +VPC +F +7 +8 +Variable +TSC +VTSC +LCRATE +PR +KCON +ISFLG +NCYCLE +Type +I +F +F +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +YM +LCPY +LCUYS +VC +PC +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus 𝐸 +Load curve ID giving pressure for plastic yielding versus +volumetric strain, see Figure M75-1. +Load curve ID giving uniaxial yield stress versus volumetric +strain, see Figure M75-1, all abscissa values should be positive if +only the results of a compression test are included, optionally the +results of a tensile test can be added (corresponding to negative +values of the volumetric strain), in the latter case PC, VPC, TC +and VTC will be ignored +Viscous damping coefficient (0.05 < recommended value < 0.50; +default is 0.05). +Pressure cutoff for hydrostatic tension. If zero, the default is set +to one-tenth of 𝑝0, the yield pressure corresponding to a +volumetric strain of zero. PC will be ignored if TC is non zero. +True Stress +optional +Uniaxial Yield +Stress (LCUYS) +Pressure Yield (LCPY) +tension +compression +Volumetric Strain +Figure M75-1. Behavior of crushable foam. Unloading is elastic. + VARIABLE +DESCRIPTION +VPC +TC +VTC +Variable pressure cutoff for hydrostatic tension as a fraction of +pressure yield value. If non-zero this will override the pressure +cutoff value PC. +Tension cutoff for uniaxial tensile stress. Default is zero. A +nonzero value is recommended for better stability. +Variable tension cutoff for uniaxial tensile stress as a fraction of +the uniaxial compressive yield strength, if non-zero this will +override the tension cutoff value TC. +LCRATE +Load curve ID giving a scale factor for the previous yield curves, +dependent upon the volumetric strain rate. +PR +KCON +Poisson coefficient, which applies to both elastic and plastic +deformations, must be smaller then 0.5 +Stiffness coefficient for contact interface stiffness. If undefined +one-third of Young’s modulus, YM, is used. KCON is also +considered in the element time step calculation; therefore, large +values may reduce the element time step size. +ISFLG +*MAT_BILKHU/DUBOIS_FOAM +DESCRIPTION +Flag for tensile response (active only if negative abscissa are +present in load curve LCUYS) +EQ.0: load curve abscissa in tensile region correspond to +volumetric strain +EQ.1: load curve abscissa in tensile region correspond to +effective strain (for large PR, when volumetric strain +vanishes) +NCYCLE +Number of cycles to determine the average volumetric strain rate. +NCYCLE is 1 by default (no smoothing) and cannot exceed 100. +Remarks: +The logarithmic volumetric strain is defined in terms of the relative volume, 𝑉, as: +If option ISFLG = 1 is used, the effective strain is defined in the usual way: +𝛾 = −ln(𝑉) +𝜀eff = √ +tr(𝛆t𝛆) +In defining the load curve LCPY the stress and strain pairs should be positive values +starting with a volumetric strain value of zero. +The load curve LCUYS can optionally contain the results of the tensile test (correspond- +ing to negative values of the volumetric strain), if so, then the load curve information +will override PC, VPC, TC and VTC. +The yield surface is defined as an ellipse in the equivalent pressure and von Mises stress +plane. This ellipse is characterized by three points: +1. +2. +3. +the hydrostatic compression limit (LCPY), +the uniaxial compression limit (LCUYS), and +either the pressure cutoff for hydrostatic stress (PC,VPC), the tension cutoff for +uniaxial tension (TC,VTC), or the optional tensile part of LCUYS. +To prevent high frequency oscillations in the strain rate from causing similar high +frequency oscillations in the yield stress, a modified volumetric strain rate is used +obtain the scaled yield stress. The modified strain rate is obtained as follows. If NYCLE +is > 1, then the modified strain rate is obtained by a time average of the actual strain +rate over NCYCLE solution cycles. The averaged strain rate is stored on history +variable #3. +*MAT_GENERAL_VISCOELASTIC_{OPTION} +The available options include: + +MOISTURE +This is Material Type 76. This material model provides a general viscoelastic Maxwell +model having up to 18 terms in the Prony series expansion and is useful for modeling +dense continuum rubbers and solid explosives. Either the coefficients of the Prony +series expansion or a relaxation curve may be specified to define the viscoelastic +deviatoric and bulk behavior. +The material model can also be used with laminated shell. Either an elastic or +viscoelastic layer can be defined with the laminated formulation. To activate laminated +shell you need the laminated formulation flag on *CONTROL_SHELL. With the +laminated option a user defined integration rule is needed. + Card 1 +1 +Variable +MID +2 +RO +3 +4 +BULK +PCF +Type +A8 +F +F +F +5 +EF +F +6 +TREF +F +7 +A +F +8 +B +F +Relaxation Curve Card. Leave blank if the Prony Series Cards are used below. Also, +leave blank if an elastic layer is defined in a laminated shell. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCID +NT +BSTART +TRAMP +LCIDK +NTK +BSTARTK TRAMPK +Type +F +I +F +F +F +I +F +F +Moisture Card. Additional card for MOISTURE keyword option. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MO +ALPHA +BETA +GAMMA +MST +Type +F +F +F +F +Prony Series cards. Card Format for viscoelastic constants. Up to 18 cards may be +input. A keyword card (with a “*” in column 1) terminates this input if less than 18 +cards are used. These cards are not needed if relaxation data is defined. The number of +terms for the shear behavior may differ from that for the bulk behavior: insert zero if a +term is not included. If an elastic layer is defined you only need to define GI and KI +(note in an elastic layer only one card is needed) + Card 4 +Variable +Type +1 +GI +F +2 +BETAI +F +3 +KI +F + VARIABLE +MID +4 +5 +6 +7 +8 +BETAKI +F +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +BULK +Elastic bulk modulus. +PCF +EF +TREF +A +B +LCID +NT +Tensile pressure elimination flag for solid elements only. If set to +unity tensile pressures are set to zero. +Elastic flag (if equal 1, the layer is elastic. If 0 the layer is +viscoelastic). +Reference temperature for shift function (must be greater than +zero). +Coefficient for the Arrhenius and the Williams-Landau-Ferry shift +functions. +Coefficient for the Williams-Landel-Ferry shift function. +Load curve ID for deviatoric relaxation behavior. If LCID is +given, constants 𝐺𝑖, and 𝛽𝑖 are determined via a least squares fit. +See Figure M76-1 for an example relaxation curve. +Number of terms in shear fit. If zero the default is 6. Fewer than +NT terms will be used if the fit produces one or more negative +shear moduli. Currently, the maximum number is set to 18. +σ∕ε +TRAMP +10n +10n+1 10n+2 10n+3 +time +optional ramp time for loading +Figure M76-1. Relaxation curves for deviatoric behavior and bulk behavior. +The ordinate of LCID is the deviatoric stress divided by (2 times the constant +value of deviatoric strain) where the stress and strain are in the direction of the +prescribed strain, or in non-directional terms, the effective stress divided by (3 +times the effective strain). LCIDK defines the mean stress divided by the +constant value of volumetric strain imposed in a hydrostatic stress relaxation +experiment, versus time. For best results, the points defined in the curve +should be equally spaced on the logarithmic scale. Note the values for the +abscissa are input as time, not log(time). Furthermore, the curve should be +smooth and defined in the positive quadrant. If nonphysical values are +determined by least squares fit, LS-DYNA will terminate with an error +message after the initialization phase is completed. If the ramp time for +loading is included, then the relaxation which occurs during the loading phase +is taken into account. This effect may or may not be important. + VARIABLE +BSTART +DESCRIPTION +In the fit, 𝛽1 is set to zero, 𝛽2 is set to BSTART, 𝛽3 is 10 times 𝛽2, +𝛽4 is 10 times 𝛽3, and so on. If zero, BSTART is determined by an +iterative trial and error scheme. +TRAMP +Optional ramp time for loading. +LCIDK +Load curve ID for bulk relaxation behavior. If LCIDK is given, +constants 𝐾𝑖, and 𝛽𝑘𝑖 are determined via a least squares fit. See +Figure M76-1 for an example relaxation curve. +VARIABLE +NTK +BSTARTK +DESCRIPTION +Number of terms desired in bulk fit. If zero the default is 6. +Currently, the maximum number is set to 18. +In the fit, 𝛽𝑘1, is set to zero, 𝛽𝑘2 is set to BSTARTK, 𝛽𝑘3 is 10 +times 𝛽𝑘2, 𝛽𝑘4 is 100 times greater than 𝛽𝑘3, and so on. If zero, +BSTARTK is determined by an iterative trial and error scheme. +TRAMPK +Optional ramp time for bulk loading. +MO +Initial moisture, 𝑀0. Defaults to zero. +ALPHA +Specifies 𝛼 as a function of moisture. +GT.0.0: Specifies a curve ID. +LT.0.0: Specifies the negative of a constant value. +BETA +Specifies 𝛽 as a function of moisture. +GT.0.0: Specifies a curve ID. +LT.0.0: Specifies the negative of a constant value. +GAMMA +Specifies 𝛾 as a function of moisture. +GT.0.0: Specifies a curve ID. +LT.0.0: Specifies the negative of a constant value. +MST +Moisture, 𝑀. If the moisture is 0.0, the moisture option is +disabled. +GT.0.0: Specifies a curve ID to make moisture a function of +time. +LT.0.0: Specifies the negative of a constant value of moisture. +GI +Optional shear relaxation modulus for the ith term +BETAI +Optional shear decay constant for the ith term +KI +Optional bulk relaxation modulus for the ith term +BETAKI +Optional bulk decay constant for the ith term +*MAT_GENERAL_VISCOELASTIC +Rate effects are taken into accounted through linear viscoelasticity by a convolution +integral of the form: +𝜎𝑖𝑗 = ∫ 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) +∂𝜀𝑘𝑙 +∂𝜏 +𝑑𝜏 +where 𝑔𝑖𝑗𝑘𝑙(𝑡−𝜏) is the relaxation functions for the different stress measures. This stress is +added to the stress tensor determined from the strain energy functional. +If we wish to include only simple rate effects, the relaxation function is represented by +18 terms from the Prony series: +𝑔(𝑡) = ∑ 𝐺𝑚𝑒−𝛽𝑚𝑡 +𝑚=1 +We characterize this in the input by shear moduli, 𝐺𝑖, and decay constants, 𝛽𝑖. An +arbitrary number of terms, up to 18, may be used when applying the viscoelastic model. +For volumetric relaxation, the relaxation function is also represented by the Prony series +in terms of bulk moduli: +𝑘(𝑡) = ∑ 𝐾𝑚𝑒−𝛽𝑘𝑚𝑡 +𝑚=1 +The Arrhenius and Williams-Landau-Ferry (WLF) shift functions account for the effects +of the temperature on the stress relaxation. A scaled time, t’, +𝑡′ = ∫ Φ(𝑇)𝑑𝑡 +is used in the relaxation function instead of the physical time. The Arrhenius shift +function is +Φ(𝑇) = exp [−𝐴 ( +− +𝑇REF +)] +and the Williams-Landau-Ferry shift function is +Φ(𝑇) = exp (−𝐴 +𝑇 − 𝑇REF +𝐵 + 𝑇 − 𝑇REF +) +If all three values (TREF, A, and B) are not zero, the WLF function is used; the +Arrhenius function is used if B is zero; and no scaling is applied if all three values are +zero. +The moisture model allows the scaling of the material properties as a function of the +moisture content of the material. The shear and bulk moduli are scaled by 𝛼, the decay +constants are scaled by β, and a moisture strain, 𝛾(𝑀)[𝑀 − 𝑀𝑂] is introduced +analogous to the thermal strain. +*MAT_HYPERELASTIC_RUBBER +This is Material Type 77. This material model provides a general hyperelastic rubber +model combined optionally with linear viscoelasticity as outlined by Christensen [1980]. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +PR +F +4 +N +I +5 +NV +I +6 +G +F +7 +8 +SIGF +REF +F +F +Hysteresis Card. Additional card read in when PR < 0 (Mullins Effect). + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TBHYS +Type +F +Card 3 for N > 0. For N > 0 a least squares fit is computed from uniaxial data. + Card 3 +1 +Variable +SGL +2 +SW +Type +F +F +3 +ST +F +4 +5 +6 +7 +8 +LCID1 +DATA +LCID2 +BSTART +TRAMP +F +F +F +F +F +Card 3 for N = 0. Set the material parameters directly. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +C10 +C01 +C11 +C20 +C02 +C30 +THERML +Type +F +F +F +F +F +F +Optional Viscoelastic Constants & Frictional Damping Constant Cards. Up to 12 +cards may be input. A keyword card (with a “*” in column 1) terminates this input if +less than 12 cards are used. + Card 4 +Variable +Type +1 +Gi +F +2 +BETAi +F +3 +Gj +F +4 +5 +6 +7 +8 +SIGFj +F + VARIABLE +DESCRIPTION +MID +RO +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Poisson’s ratio (> .49 is recommended, smaller values may not +work and should not be used). If this is set to a negative number, +then the absolute value is used and an extra card is read for +Mullins effect. +TBHYS +Table ID for hysteresis, could be positive or negative, see +Remarks 1 and 2. +N +Number of constants to solve for: +EQ.1: Solve for C10 and C01 +EQ.2: Solve for C10, C01, C11, C20, and C02 +EQ.3: Solve for C10, C01, C11, C20, C02, and C30 +NV +Number of Prony series terms in fit. If zero, the default is 6. +Currently, the maximum number is set to 12. Values less than 12, +possibly 3 - 5 are recommended, since each term used adds +significantly to the cost. Caution should be exercised when +taking the results from the fit. + Preferably, all generated +coefficients should be positive. Negative values may lead to +unstable results. Once a satisfactory fit has been achieved it is +recommended that the coefficients which are written into the +output file be input in future runs. +VARIABLE +DESCRIPTION +G +SIGF +REF +Shear modulus for frequency independent damping. Frequency +independent damping is based of a spring and slider in series. +The critical stress for the slider mechanism is SIGF defined below. +For the best results, the value of G should be 250 - 1000 times +greater than SIGF. +Limit stress for frequency independent frictional damping. +Use reference geometry to initialize the stress tensor. The +reference geometry is defined by the keyword:*INITIAL_FOAM_- +REFERENCE_GEOMETRY . +EQ.0.0: off, +EQ.1.0: on. +If N>0 test information from a uniaxial test are used. +SGL +SW +ST +LCID1 +Specimen gauge length +Specimen width +Specimen thickness +Load curve ID giving the force versus actual change in the gauge +length. If SGL, SW, and ST are set to unity (1.0), then curve +LCID1 is also engineering stress versus engineering strain. +DATA +Type of experimental data. +EQ.0.0: uniaxial data (Only option for this model) +LCID2 +Load curve ID of the deviatoric stress relaxation curve, neglecting +the long term deviatoric stress. If LCID2 is given, constants 𝐺𝑖 +and 𝛽𝑖 are determined via a least squares fit. See M76-1 for an +example relaxation curve. The ordinate of the curve is the +viscoelastic deviatoric stress divided by (2 times the constant +value of deviatoric strain) where the stress and strain are in the +direction of the prescribed strain, or in non-directional terms, the +effective stress divided by (3 times the effective strain). +BSTART +In the fit, 𝛽1 is set to zero, 𝛽2 is set to BSTART, 𝛽3 is 10 times 𝛽2, +𝛽4 is 10 times 𝛽3, and so on. If zero, BSTART is determined by an +iterative trial and error scheme. +TRAMP +Optional ramp time for loading. +VARIABLE +DESCRIPTION +If N=0, the following constants have to be defined: +C10 +C01 +C11 +C20 +C02 +C30 +𝐶10 +𝐶01 +𝐶11 +𝐶20 +𝐶02 +𝐶30 +THERML +Flag for the thermal option. If THERML > 0.0, then G, SIGF, C10 +and C01 specify curve IDs giving the values as functions of +temperature, otherwise they specify the constants. This option is +available only for solid elements. +Gi +Optional shear relaxation modulus for the ith term +BETAi +Optional decay constant if ith term +Gj +SIGFj +Optional shear modulus for frequency independent damping +represented as the jth spring and slider in series in parallel to the +rest of the stress contributions. +Limit stress for frequency independent, frictional, damping +represented as the jth spring and slider in series in parallel to the +rest of the stress contributions. +Background: +Rubber is generally considered to be fully incompressible since the bulk modulus +greatly exceeds the shear modulus in magnitude. To model the rubber as an +unconstrained material a hydrostatic work term, 𝑊𝐻(𝐽), is included in the strain energy +functional which is function of the relative volume, 𝐽, [Ogden 1984]: +𝑊(𝐽1, 𝐽2, 𝐽) = ∑ 𝐶𝑝𝑞(𝐽1 − 3)𝑝(𝐽2 − 3)𝑞 + 𝑊𝐻(𝐽) +𝑝,𝑞=0 +−1 +𝐽1 = 𝐼1𝐼3 +−2 +𝐽2 = 𝐼2𝐼3 +3⁄ +3⁄ +In order to prevent volumetric work from contributing to the hydrostatic work the first +and second invariants are modified as shown. This procedure is described in more +detail by Sussman and Bathe [1987]. +Rate effects are taken into account through linear viscoelasticity by a convolution +integral of the form: +𝜎𝑖𝑗 = ∫ 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) +∂𝜀𝑘𝑙 +∂𝜏 +𝑑𝜏 +or in terms of the second Piola-Kirchhoff stress, 𝑆𝑖𝑗, and Green's strain tensor, 𝐸𝑖𝑗, +𝑆𝑖𝑗 = ∫ 𝐺𝑖𝑗𝑘𝑙(𝑡 − 𝜏) +∂𝐸𝑘𝑙 +∂𝜏 +𝑑𝜏 +where 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) and 𝐺𝑖𝑗𝑘𝑙(𝑡 − 𝜏) are the relaxation functions for the different stress +measures. This stress is added to the stress tensor determined from the strain energy +functional. +If we wish to include only simple rate effects, the relaxation function is represented by +six terms from the Prony series: +given by, +𝑔(𝑡) = 𝛼0 + ∑ 𝛼𝑚𝑒−𝛽𝑡 +𝑚=1 +𝑔(𝑡) = ∑ 𝐺𝑖𝑒−𝛽𝑖𝑡 +𝑖=1 +This model is effectively a Maxwell fluid which consists of a dampers and springs in +series. We characterize this in the input by shear moduli, 𝐺𝑖, and decay constants, 𝛽𝑖. +The viscoelastic behavior is optional and an arbitrary number of terms may be used. In +order to avoid a constant shear modulus from this visco-elastic formulation, a term in +the series is included only when 𝛽𝑖 > 0. +The Mooney-Rivlin rubber model (model 27) is obtained by specifying 𝑛 = 1. In spite of +the differences in formulations with model 27, we find that the results obtained with +this model are nearly identical with those of material 27 as long as large values of +Poisson’s ratio are used. +The frequency independent damping is obtained by the having a spring and slider in +series as shown in the following sketch: +friction +Several springs and sliders in series can be defined that are put in parallel to the rest of +the stress contributions of this material model. +*MAT_HYPERELASTIC_RUBBER +1. Hysteresis (TBHYS > 0). If a positive table ID for hysteresis is defined, then +TBHYS is a table having curves that are functions of strain-energy density. Let +𝑊dev be the current value of the deviatoric strain energy density as calculated +above. Furthermore, let 𝑊̅̅̅̅̅̅dev be the peak strain energy density reached up to +this point in time. It is then assumed that the resulting stress is reduced by a +damage factor according to +𝐒 = 𝐷(𝑊dev, 𝑊̅̅̅̅̅̅dev) +∂𝑊dev +∂𝐄 ++ +∂𝑊vol +∂𝐄 +. +where 𝐷(𝑊dev, 𝑊̅̅̅̅̅̅dev) is the damage factor which is input as the table, TBHYS. +This table consists of curves giving stress reduction (between 0 and 1) as a func- +tion of 𝑊dev indexed by 𝑊̅̅̅̅̅̅dev. +Each 𝑊̅̅̅̅̅̅dev curve must be valid for strain energy densities between 0 and 𝑊̅̅̅̅̅̅dev. +It is recommended that each curve be monotonically increasing, and it is required +that each curve equals 1 when 𝑊dev > 𝑊̅̅̅̅̅̅dev. Additionally, *DEFINE_TABLE +requires that each curve have the same beginning and end point and, further- +more, that they not cross except at the boundaries, although they are not re- +quired to cross. +This table can be estimated from a uniaxial quasistatic compression test as fol- +lows: +a) Load the specimen to a maximum displacement 𝑑 ̅ and measure the force +as function of displacement: 𝑓load(𝑑 ̅). +b) Unload the specimen again measuring the force as a function of displace- +ment: 𝑓unload(𝑑). +c) The strain energy density is, then, given as a function of the loaded dis- +placement as +𝑊dev(𝑑) = +∫ 𝑓load(𝑠)𝑑𝑠 +. +i) +ii) +The peak energy, which is used to index the data set, is given by +𝑊̅̅̅̅̅̅dev = 𝑊dev(𝑑 ̅). +From this energy curve we can also determine the inverse: +𝑑(𝑊dev). Using this inverse the load curve for LS-DYNA is then +given by: +𝐷(𝑊dev, 𝑊̅̅̅̅̅̅dev) = +𝑓unload[𝑑(𝑊dev)] +𝑓load[𝑑(𝑊dev)] +. +d) This procedure is repeated for different values of 𝑑 ̅ (or equivalently 𝑊̅̅̅̅̅̅dev). +2. Hysteresis (TBHYS < 0). If a negative table ID for hysteresis is defined, then +all of the above holds. The difference being that the load curves comprising +table, |TBHYS|, must give the strain-energy density, 𝑊dev, as a function of the +stress reduction factor. This scheme guarantees that all curves have the same begin- +ning point, 0, and the same end point, 1. For negative TBHYS the user provides +𝑊dev(𝐷, 𝑊̅̅̅̅̅̅dev) instead of 𝐷(𝑊dev, 𝑊̅̅̅̅̅̅dev). In practice, this case corresponds to +swapping the load curve axes. +*MAT_OGDEN_RUBBER +This is also Material Type 77. This material model provides the Ogden [1984] rubber +model combined optionally with linear viscoelasticity as outlined by Christensen [1980]. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +PR +F +4 +N +I +5 +NV +I +6 +G +F +7 +8 +SIGF +REF +F +F +Hysteresis Card. Additional card read in when PR < 0 (Mullins Effect). + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TBHYS +Type +F +Card 3 for N > 0. For N > 0 a least squares fit is computed from uniaxial data. + Card 3 +1 +Variable +SGL +2 +SW +Type +F +F +3 +ST +F +4 +5 +6 +7 +8 +LCID1 +DATA +LCID2 +BSTART +TRAMP +F +F +F +F +Card 3 for N = 0. Set the material parameters directly. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MU1 +MU2 +MU3 +MU4 +MU5 +MU6 +MU7 +MU8 +Type +F +F +F +F +F +F +F +Card 4 for N = 0. Set the material parameters directly. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ALPHA1 +ALPHA2 +ALPHA3 +ALPHA4 +ALPHA5 +ALPHA6 +ALPHA7 +ALPHA8 +Type +F +F +F +F +F +F +F +F +Optional Viscoelastic Constants Cards. Up to 12 cards may be input. A keyword +card (with a “*” in column 1) terminates this input if less than 12 cards are used. +1 +GI +F + Card 5 +Variable +Type +Default +2 +3 +4 +5 +6 +7 +8 +BETAI +VFLAG +F +I +0 + VARIABLE +DESCRIPTION +MID +RO +PR +N +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Poisson’s ratio (≥ 49 is recommended; smaller values may not +work and should not be used). If this is set to a negative number, +then the absolute value is used and an extra card is read for +Mullins effect. +Order of fit to the Ogden model, (currently < 9, 2 generally works +okay). The constants generated during the fit are printed in the +output file and can be directly input in future runs, thereby, +saving the cost of performing the nonlinear fit. The users need to +check the correction of the fit results before proceeding to +compute. +VARIABLE +NV +G +SIGF +REF +DESCRIPTION +Number of Prony series terms in fit. If zero, the default is 6. +Currently, the maximum number is set to 12. Values less than 12, +possibly 3-5 are recommended, since each term used adds +significantly to the cost. Caution should be exercised when +taking the results from the fit. + Preferably, all generated +coefficients should be positive. Negative values may lead to +unstable results. Once a satisfactory fit has been achieved it is +recommended that the coefficients which are written into the +output file be input in future runs. +Shear modulus for frequency independent damping. Frequency +independent damping is based on a spring and slider in series. +The critical stress for the slider mechanism is SIGF defined below. +For the best results, the value of G should be 250-1000 times +greater than SIGF. +Limit stress for frequency independent frictional damping. +Use reference geometry to initialize the stress tensor. The +reference geometry is defined by the keyword: *INITIAL_- +FOAM_REFERENCE_GEOMETRY . +EQ.0.0: off, +EQ.1.0: on. +TBHYS +Table ID for hysteresis, could be positive or negative, see +Remarks on *MAT_HYPERELASTIC_RUBBER +If N > 0 test information from a uniaxial test are used: +SGL +SW +ST +LCID1 +Specimen gauge length +Specimen width +Specimen thickness +Load curve ID giving the force versus actual change in the gauge +length. If SGL, SW, and ST are set to unity (1.0), then curve +LCID1 is also engineering stress versus engineering strain. +VARIABLE +DESCRIPTION +DATA +Type of experimental data. +EQ.1.0: uniaxial data (default) +EQ.2.0: biaxial data +EQ.3.0: pure shear data +LCID2 +Load curve ID of the deviatoric stress relaxation curve, neglecting +the long term deviatoric stress. If LCID2 is given, constants 𝐺𝑖 +and 𝛽𝑖 are determined via a least squares fit. See M76-1 for an +example relaxation curve. The ordinate of the curve is the +viscoelastic deviatoric stress divided by (2 times the constant +value of deviatoric strain) where the stress and strain are in the +direction of the prescribed strain, or in non-directional terms, the +effective stress divided by (3 times the effective strain). +BSTART +In the fit, 𝛽𝑖 is set to zero, 𝛽2 is set to BSTART, 𝛽3 is 10 times 𝛽2, +𝛽4 is 10 times 𝛽3 , and so on. If zero, BSTART is determined by an +iterative trial and error scheme. +TRAMP +Optional ramp time for loading. +MUi +𝜇𝑖, the ith shear modulus, i varies up to 8. See discussion below. +ALPHAi +𝛼𝑖, the ith exponent, i varies up to 8. See discussion below. +Gi +Optional shear relaxation modulus for the ith term +BETAi +Optional decay constant if ith term +Flag for the viscoelasticity formulation. This appears only on the +first line defining Gi, BETAi, and VFLAG. If VFLAG = 0, the +standard viscoelasticity formulation is used (the default), and if +the +viscoelasticity +the +VFLAG = 1, +instantaneous elastic stress is used. +formulation using +VFLAG +Remarks: +Rubber is generally considered to be fully incompressible since the bulk modulus +greatly exceeds the shear modulus in magnitude. To model the rubber as an +unconstrained material a hydrostatic work term is included in the strain energy +functional which is function of the relative volume, 𝐽, [Ogden 1984]: +𝑊∗ = ∑ ∑ +𝑗=1 +𝑖=1 +𝜇𝑗 +𝛼𝑗 +∗𝛼𝑗 − 1) + 𝐾(𝐽 − 1 − ln𝐽) +(𝜆𝑖 +The asterisk (*) indicates that the volumetric effects have been eliminated from the +∗. The number of terms, n, may vary from 1 to 8 inclusive, and 𝐾 is +principal stretches, 𝜆𝑗 +the bulk modulus. +Rate effects are taken into account through linear viscoelasticity by a convolution +integral of the form: +𝜎𝑖𝑗 = ∫ 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) +∂𝜀𝑘𝑙 +∂𝜏 +𝑑𝜏 +or in terms of the second Piola-Kirchhoff stress, 𝑆ij , and Green's strain tensor, 𝐸𝑖𝑗, +𝑆𝑖𝑗 = ∫ 𝐺𝑖𝑗𝑘𝑙(𝑡 − 𝜏) +∂𝐸𝑘𝑙 +∂𝜏 +𝑑𝜏 +where 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) and 𝐺𝑖𝑗𝑘𝑙(𝑡 − 𝜏) are the relaxation functions for the different stress +measures. This stress is added to the stress tensor determined from the strain energy +functional. +If we wish to include only simple rate effects, the relaxation function is represented by +six terms from the Prony series: +given by, +𝑔(𝑡) = 𝛼0 + ∑ 𝛼𝑚𝑒−𝛽𝑡 +𝑚=1 +𝑔(𝑡) = ∑ 𝐺𝑖𝑒−𝛽𝑖𝑡 +𝑖=1 +This model is effectively a Maxwell fluid which consists of a dampers and springs in +series. We characterize this in the input by shear moduli, 𝐺𝑖, and decay constants, 𝛽𝑖. +The viscoelastic behavior is optional and an arbitrary number of terms may be used. In +order to avoid a constant shear modulus from this viscoelastic formulation, a term in +the series is included only when 𝛽𝑖 > 0. +For VFLAG = 1, the viscoelastic term is +𝜎𝑖𝑗 = ∫ 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) +∂𝜎𝑘𝑙 +∂𝜏 +𝑑𝜏 +𝐸 is the instantaneous stress evaluated from the internal energy functional. The +where 𝜎𝑘𝑙 +coefficients in the Prony series therefore correspond to normalized relaxation moduli +instead of elastic moduli. +The Mooney-Rivlin rubber model (model 27) is obtained by specifying 𝑛 = 1. In spite of +the differences in formulations with Model 27, we find that the results obtained with +this model are nearly identical with those of Material 27 as long as large values of +Poisson’s ratio are used. +The frequency independent damping is obtained by the having a spring and slider in +series as shown in the following sketch: +friction +*MAT_SOIL_CONCRETE +This is Material Type 78. This model permits concrete and soil to be efficiently +modeled. See the explanations below. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +Variable +1 +PC +2 +RO +F +2 +OUT +Type +F +F +3 +G +F +3 +B +F +4 +K +F +4 +FAIL +F +5 +6 +7 +8 +LCPV +LCYP +LCFP +LCRP +F +5 +F +6 +F +7 +F +8 + VARIABLE +DESCRIPTION +MID +RO +G +K +LCPV +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Shear modulus +Bulk modulus +Load curve ID for pressure versus volumetric strain. The +pressure versus volumetric strain curve is defined in compression +only. The sign convention requires that both pressure and +compressive strain be defined as positive values where the +compressive strain is taken as the negative value of the natural +logarithm of the relative volume. +LCYP +Load curve ID for yield versus pressure: +GT.0: von Mises stress versus pressure, +LT.0: Second stress invariant, J2, versus pressure. This curve +must be defined. +1.0 +Figure M78-1. Strength reduction factor. + VARIABLE +DESCRIPTION +LCFP +LCRP +PC +OUT +Load curve ID for plastic strain at which fracture begins versus +pressure. This load curve ID must be defined if B > 0.0. +Load curve ID for plastic strain at which residual strength is +reached versus pressure. This load curve ID must be defined if +B > 0.0. +Pressure cutoff for tensile fracture +Output option for plastic strain in database: +EQ.0: volumetric plastic strain, +EQ.1: deviatoric plastic strain. +B +Residual strength factor after cracking, see Figure M78-1. +FAIL +Flag for failure: +EQ.0: no failure, +EQ.1: When pressure reaches failure pressure element is +eroded, +EQ.2: When pressure reaches failure pressure element loses it +ability to carry tension. +Remarks: +Pressure is positive in compression. Volumetric strain is defined as the natural log of +the relative volume and is positive in compression where the relative volume, V, is the +*MAT_SOIL_CONCRETE +Figure M78-2. Cracking strain versus pressure. +ratio of the current volume to the initial volume. The tabulated data should be given in +order of increasing compression. If the pressure drops below the cutoff value specified, +it is reset to that value and the deviatoric stress state is eliminated. +If the load curve ID (LCYP) is provided as a positive number, the deviatoric, perfectly +plastic, pressure dependent, yield function φ, is given as +𝜙 = √3J2 − 𝐹(𝑝) = 𝜎𝑦 − 𝐹(𝑝) +where , F(p) is a tabulated function of yield stress versus pressure, and the second +invariant, J2, is defined in terms of the deviatoric stress tensor as: +𝐽2 = +𝑆𝑖𝑗𝑆𝑖𝑗 +assuming that if the ID is given as negative then the yield function becomes: +being the deviatoric stress tensor. +𝜙 = 𝐽2 − 𝐹(𝑝) +If cracking is invoked by setting the residual strength factor, B, on card 2 to a value +between 0.0 and 1.0, the yield stress is multiplied by a factor f which reduces with +plastic strain according to a trilinear law as shown in Figure M78-1. +���� = residual strength factor +1 = plastic stain at which cracking begins. +2 = plastic stain at which residual strength is reached. +ε1 and ε2 are tabulated functions of pressure that are defined by load curves, see Figure +M78-2. The values on the curves are pressure versus strain and should be entered in +order of increasing pressure. The strain values should always increase monotonically +with pressure. +By properly defining the load curves, it is possible to obtain the desired strength and +ductility over a range of pressures, see Figure M78-3. +Yield +stress +p3 +p2 +p1 +Figure M78-3. Yield stress as a function of plastic strain. +Plastic strain +*MAT_HYSTERETIC_SOIL +This is Material Type 79. This model is a nested surface model with up to ten +superposed “layers” of elasto-perfectly plastic material, each with its own elastic +moduli and yield values. Nested surface models give hysteric behavior, as the different +“layers” yield at different stresses. See Remarks below. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F + Card 2 +Variable +1 +DF +Type +F + Card 3 +1 +2 +RP +F +2 +3 +K0 +F +3 +4 +P0 +F +4 +5 +B +F +5 +6 +A0 +F +6 +7 +A1 +F +7 +8 +A2 +F +8 +LCID +SFLC +DIL_A +DIL_B +DIL_C +DIL_D +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +GAM1 +GAM2 +GAM3 +GAM4 +GAM5 +LCD +LCSR +PINIT +Type +F + Card 4 +1 +F +2 +F +3 +F +4 +F +5 +I +6 +I +7 +I +8 +Variable +TAU1 +TAU2 +TAU3 +TAU4 +TAU5 +Type +F +F +F +F +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +VARIABLE +DESCRIPTION +K0 +P0 +B +A0 +A1 +A2 +DF +RP +LCID +Bulk modulus at the reference pressure +Cut-off/datum pressure (must be 0≤ i.e. tensile). Below this +pressure, stiffness and strength disappears; this is also the “zero” +pressure for pressure-varying properties. +B is the exponent for the pressure-sensitive elastic moduli. See +remarks. B must be in the range 0 ≤ 𝐵 < 1, and values too close +to 1 are not recommended because the pressure becomes +indeterminate. +Yield function constant a0 (Default = 1.0), see Material Type 5. +Yield function constant a1 (Default = 0.0), see Material Type 5. +Yield function constant a2 (Default = 0.0), see Material Type 5. +Damping factor. Must be in the range 0≤df≤1: +EQ.0: no damping, +EQ.1: maximum damping. +Reference pressure for following input data. +Load curve ID defining shear strain verses shear stress. Up to ten +points may be defined in the load curve. See *DEFINE_CURVE. +SFLD +Scale factor to apply to shear stress in LCID. +DIL_A +DIL_B +DIL_C +DIL_D +GAM1 +GAM2 +GAM3 +GAM4 +Dilation parameter A +Dilation parameter B +Dilation parameter C +Dilation parameter D +γ1, shear strain (ignored if LCID is non zero). +γ2, shear strain (ignored if LCID is non zero). +γ3, shear strain (ignored if LCID is non zero). +γ4, shear strain (ignored if LCID is non zero). +GAM5 +LCD +LCSR +*MAT_HYSTERETIC_SOIL +DESCRIPTION +γ5, shear strain (ignored if LCID is non zero). +strain amplitudes +Optional Load Curve ID defining damping ratio of hysteresis at +different +for +unload/reload). The x-axis is shear strain, the y-axis is the +damping ratio (e.g., 0.05 for 5% damping). The strains (x-axis +values) of curve LCD must be identical to those of curve LCID. +(overrides Masing +rules +Load curve ID defining plastic strain rate scaling effect on yield +stress. See *DEFINE_CURVE. The x-axis is plastic strain rate, the +y-axis is the yield enhancement factor. +PINIT +Flag for pressure sensitivity (B and A0, A1, A2 equations): +EQ.0: Use current pressure (will vary during the analysis) +EQ.1: Use pressure from initial stress state +EQ.2: Use initial “plane stress” pressure (𝜎𝑣 + 𝜎ℎ)/2 +EQ.3: User (compressive) initial vertical stress +τ1, shear stress at γ1 (ignored if LCID is non zero). +τ2, shear stress at γ2 (ignored if LCID is non zero). +τ3, shear stress at γ3 (ignored if LCID is non zero). +τ4, shear stress at γ4 (ignored if LCID is non zero). +τ5, shear stress at γ5 (ignored if LCID is non zero). +TAU1 +TAU2 +TAU3 +TAU4 +TAU5 +Remarks: +The elastic moduli G and K are pressure sensitive: +𝐺(𝑝) = +𝐾(𝑝) = +𝐺0(𝑝 − 𝑝0)𝑏 +(𝑝ref − 𝑝0)𝑏 +𝐾0(𝑝 − 𝑝0)𝑏 +(𝑝ref − 𝑝0)𝑏 +where G0 and K0 are the input values, p is the current pressure, p0 the cut-off or datum +pressure (must be zero or negative). If p attempts to fall below p0 (i.e., more tensile) the +shear stresses are set to zero and the pressure is set to p0. Thus, the material has no +stiffness or strength in tension. The pressure in compression is calculated as follows: +𝑝 = 𝑝ref [− +⁄ +(1−𝑏) +𝐾0 +𝑝ref +ln(𝑉)] +where V is the relative volume, i.e., the ratio between the original and current volume. +This formula results in an instantaneous bulk modulus proportional to pb whose value +at the reference pressure is equal to K0/(1-b). +The constants a0, a1, a2 govern the pressure sensitivity of the yield stress. Only the +ratios between these values are important - the absolute stress values are taken from the +stress-strain curve. +The stress strain pairs define a shear stress versus shear strain curve. The first point on +the curve is assumed by default to be (0,0) and does not need to be entered. The slope +of the curve must decrease with increasing γ. This curves applies at the reference +pressure; at other pressures the curve is scaled by +𝜏(𝑝, 𝛾) +𝜏(𝑝𝑟𝑒𝑓 , 𝛾) += √ +[𝑎0 + 𝑎1(𝑝 − 𝑝0) + 𝑎2(𝑝 − 𝑝0)2] +[𝑎0 + 𝑎1(𝑝ref − 𝑝0) + 𝑎2(𝑝ref − 𝑝0)2] +The shear stress-strain curve (with points (τ1,γ1), (τ2,γ2)...(τN,γN)) is converted into a series +of N elastic perfectly-plastic curves such that ∑(𝜏𝑖, (𝛾)) = 𝜏(𝛾), as shown in the figure +below. +elasto-plastic 1 +elasto-plastic 2 +shear strain +elasto-plastic 3 +elasto-plastic 4 +Figure M79-1. +low pressure +Each elastic perfectly-plastic curve represents one “layer” in the material model. +Deviatoric stresses are stored and calculated separately for each layer. The total +deviatoric stress is the sum of the deviatoric stresses in each layer. By this method, +hysteretic (energy-absorbing) stress-strain curves are generated in response to any +strain cycle of amplitude greater than the lowest yield strain of any layer. The example +below shows response to small and large strain cycles (blue and pink lines) superposed +on the input curve (thick red line). +) +( +60 +40 +20 +-20 +-40 +-60 +backbone curve +shear strain amplitude: 0.16% +shear strain amplitude: 0.06% +-0.2 +-0.1 +0.1 +0.2 +0.3 +0.4 +shear strain % +Figure M79-2. +Definition of shear strain and shear stress: +Different definitions of “shear strain” and “shear stress” are possible when applied to +the three-dimensional stress states. MAT_079 uses the following definitions: +Input shear stress is treated by the material model as, +0.5 × Von Mises Stress = √(3𝜎′𝑖: 𝜎′𝑖 8⁄ ). +Input shear strain is treated by the material model as +1.5 × Von Mises Strain = √(3𝜀′𝑖: 𝜀′𝑖 2⁄ ). +For a particular stress or strain state (defined by the relationship between the three +principal stresses or strains), a scaling factor may be needed in order to convert between +the definitions given above and the shear stress or strain that an engineer would expect. +The MAT_079 definitions of shear stress and shear strain are derived from triaxial +testing in which one principal stress is applied, while the other two principal stresses +are equal to a confining stress which is held constant, i.e. principal stresses and strains +have the form (a, b, b). If instead the user wishes the input curve to represent a test in +which a pure shear strain is applied over a hydrostatic pressure, such as a shear-box +text, then it is recommended to scale both the x-axis and the y-axis of the curve by 0.866. +This factor assumes principal stresses of the form (p+t, p-t, p) where t is the applied +shear stress, and similar for the principal strains. +Pressure Sensitivity: +The yield stresses of the layers, and hence the stress at each point on the shear stress- +strain input curve, vary with pressure according to constants A0, A1 and A2. The +elastic moduli, and hence also the slope of each section of shear stress-strain curve, vary +with pressure according to constant B. These effects combine to modify the shear +stress-strain curve according to pressure: +1 ≠ θ +2, slope +varies with pressure +according to B +stress varies +with pressure +according to +A0, A1, and A2 +at different P, same point on +the input stress-strain curve +will be reached at different strain +high pressure (P2) +low pressure (P1) +shear strain +Figure M79-3. +Pressure sensitivity can make the solution sensitive to numerical noise. In cases where +the expected pressure changes are small compared to the initial stress state, it may be +preferable to use pressure from the initial stress state instead of current pressure as the +basis for the pressure sensitivity (option PINIT). This causes the bulk modulus and +shear stress-strain curve to be calculated once for each element at the start of the +analysis and to remain fixed thereafter. PINIT affects both stiffness (calculated using B) +and strength (calculated using A0, A1 and A2). If PINIT options 2 (“plane stress” +pressure) or 3 (vertical stress) are used, these quantities substitute for pressure p in the +equations above. Input values of pref and p0 should then also be “plane stress” pressure +or vertical stress, respectively. +If PINIT is used, B is allowed to be as high as 1.0 (stiffness proportional to initial +pressure); otherwise, values of B higher than about 0.5 are not recommended. +Dilatancy: +Parameters DIL_A, DIL_B, DIL_C and DIL_D control the compaction and dilatancy that +occur in sandy soils as a result of shearing motion. The dilatancy is expressed as a +volume strain γv: +𝜀v = 𝜀r + 𝜀g +𝜀r = DIL_ A(Γ)DIL_ B +𝜀g = +∫(𝑑𝛾𝑥𝑧 +2⁄ +2 ) +2 + 𝑑𝛾𝑦𝑧 +DIL_ C + DIL_ D × ∫(𝑑𝛾𝑥𝑧 +2⁄ +2 ) +2 + 𝑑𝛾𝑦𝑧 +Γ = (𝛾𝑥𝑧 +2⁄ +2 ) +2 + 𝛾𝑦𝑧 +𝛾𝑥𝑧 = 2𝜀𝑥𝑧 +𝛾𝑦𝑧 = 2𝜀𝑦𝑧 +γr describes the dilation of the soil due to the magnitude of the shear strains; this is +caused by the soil particles having to climb over each other to develop shear strain. +γg describes compaction of the soil due to collapse of weak areas and voids, caused by +continuous shear straining. +Recommended inputs for sandy soil: +DIL_A +DIL_B +DIL_C +DIL_D +- 10 +- 1.6 +- 100 +- 2.5 +DIL_A and DIL_B may cause instabilities in some models. If this facility is used with +pore water pressure, liquefaction can be modeled. +Strain rate sensitivity: +Strain rate effect is accounted for by scaling the yield stress of each layer as the user- +specified function of plastic strain rate. The stress-strain curve defined by LCID is +considered as the reference curve or the curve for the lowest shear strength among all +plastic strain rates. Scale factor versus strain rate is defined in curve LCSR. All scale +factors must be equal to or larger than 1.0. For a given plastic strain rate, the effective +scale factor for the resultant stress (instead of layer stresses) is 1.0 for elastic range and +ramping up to the one corresponding to the given plastic strain rate when the stress is +approaching the ultimate yield stress (last point of curve LCID). +*MAT_RAMBERG-OSGOOD +This is Material Type 80. This model is intended as a simple model of shear behavior +and can be used in seismic analysis. + Card 1 +1 +Variable +MID +2 +RO +3 +4 +5 +GAMY +TAUY +ALPHA +Type +A8 +F +F +F +F +6 +R +F +7 +8 +BULK +F +Default +none +none +none +none +none +none +none + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +GAMY +TAUY +Reference shear strain (γy) +Reference shear stress (τy) +ALPHA +Stress coefficient (α) +R +Stress exponent (r) +BULK +Elastic bulk modulus +Remarks: +The Ramberg-Osgood equation is an empirical constitutive relation to represent the +one-dimensional elastic-plastic behavior of many materials, including soils. This model +allows a simple rate independent representation of the hysteretic energy dissipation +observed in soils subjected to cyclic shear deformation. For monotonic loading, the +stress-strain relationship is given by: +𝛾𝑦 +𝛾𝑦 += += +𝜏𝑦 +𝜏𝑦 +∣ +∣ ++ 𝛼 ∣ +𝜏𝑦 +− 𝛼 ∣ +𝜏𝑦 +, for 𝛾 ≥ 0 +, for 𝛾 < 0 +where 𝛾 is the shear and 𝜏 is the stress. The model approaches perfect plasticity as the +stress exponent 𝑟 → ∞. These equations must be augmented to correctly model +unloading and reloading material behavior. The first load reversal is detected by +𝛾𝛾̇ < 0. After the first reversal, the stress-strain relationship is modified to +(𝛾 − 𝛾0) +2𝛾𝑦 +(𝛾 − 𝛾0) +2𝛾𝑦 += += +(𝜏 − 𝜏0) +2𝜏𝑦 +(𝜏 − 𝜏0) +2𝜏𝑦 ++ 𝛼 ∣ +− 𝛼 ∣ +′ +(𝜏 − 𝜏0) +∣ +2𝜏𝑦 +′ +(𝜏 − 𝜏0) +∣ +2𝜏𝑦 +, for 𝛾 ≥ 0 +, for 𝛾 < 0 +where 𝛾0 and 𝜏0 represent the values of strain and stress at the point of load reversal. +Subsequent load reversals are detected by (𝛾 − 𝛾0)𝛾̇ < 0. +The Ramberg-Osgood equations are inherently one-dimensional and are assumed to +apply to shear components. To generalize this theory to the multidimensional case, it is +assumed that each component of the deviatoric stress and deviatoric tensorial strain is +independently related by the one-dimensional stress-strain equations. A projection is +used to map the result back into deviatoric stress space if required. The volumetric +behavior is elastic, and, therefore, the pressure p is found by +where 𝜀𝑣 is the volumetric strain. +𝑝 = −𝐾𝜀𝑣 +*MAT_PLASTICITY_WITH_DAMAGE_{OPTION} +This manual entry apply to both types 81 and 82. Materials 81 and 82 model an elasto- +visco-plastic material with user-defined isotropic stress versus strain curves, which, +themselves, may be strain-rate dependent. This model accounts for the effects of +damage prior to rupture based on an effective plastic-strain measure. Additionally, +failure can be triggered when the time step drops below some specified value. +Available options include: + +ORTHO +ORTHO_RCDC +ORTHO_RCDC1980 +STOCHAS +The ORTHO option invokes an orthotropic damage model, an extension that was first +added as for modelling failure in aluminum panels. Directional damage begins after a +defined failure strain is reached in tension and continues to evolve until a tensile +rupture strain is reached in either one of the two orthogonal directions. After rupture is +detected at all integration points, the element is deleted. +The ORTHO_RCDC option invokes the damage model developed by Wilkins [Wilkins, +et al. 1977]. The ORTHO_RCDC1980 option invokes a damage model based on strain +invariants as developed by Wilkins [Wilkins, et al. 1980]. A nonlocal formulation, +which requires additional storage, is used if a characteristic length is defined. The +RCDC option, which was added at the request of Toyota, works well in predicting +failure in cast aluminum; see Yamasaki, et al., [2006]. +NOTE: This keyword, in its long form, *MAT_PLASTICI- +TY_WITH_DAMAGE, with no options invokes ma- +terial type 81. Adding an orthotropic damage option +will invoke material type 82. Since type 82 must +track directional strains it is, computationally, more +expensive. +Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +6 +7 +8 +SIGY +ETAN +EPPF +TDEL +F +F +F +F +Default +none +none +none +none +none +0.0 +1012 +0.0 + Card 2 +Variable +Type +Default +1 +C +F +0 + Card 3 +1 +2 +P +F +0 +2 +3 +4 +5 +LCSS +LCSR +EPPFR +F +0 +3 +F +0 +4 +F +1014 +5 +6 +VP +F +0 +6 +7 +8 +LCDM +NUMINT +F +0 +7 +I +0 +8 +Variable +EPS1 +EPS2 +EPS3 +EPS4 +EPS5 +EPS6 +EPS7 +EPS8 +Type +Default +F +0 + Card 4 +1 +F +0 +2 +F +0 +3 +F +0 +4 +F +0 +5 +F +0 +6 +F +0 +7 +F +0 +8 +Variable +ES1 +ES2 +ES3 +ES4 +ES5 +ES6 +ES7 +ES8 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +Ortho RCDC Card. Additional card for keyword option ORTHO_RCDC. + Card 5 +1 +2 +3 +4 +Variable +ALPHA +BETA +GAMMA +D0 +Type +Default +F +0 +F +0 +F +0 +F +0 +5 +B +F +0 +6 +7 +LAMBDA +DS +F +0 +F +0 +8 +L +F +0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +SIGY +ETAN +EPPF +TDEL +C +P +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +Yield stress. +Tangent modulus, ignored if (LCSS.GT.0) is defined. +𝜀failure +, effective plastic strain at which material softening begins. +Minimum time step size for automatic element deletion. +Strain rate parameter, 𝐶, see formula below. +Strain rate parameter, 𝑃, see formula below. +LCSS +Load curve ID or Table ID. +1. Case 1: LCSS is a load curve ID. The load curve LCSS maps +effective plastic strain to effective stress. If the fields +EPS1 - EPS8 and ES1 - ES8 are defined, they are ignored. +2. Case 2: LCSS is a Table ID. Each strain rate value is +associated to a load curve ID giving the stress as a func- +tion of effective plastic strain for that rate, See Figure +M24-1. The stress versus effective plastic strain curve for +the lowest value of strain rate is used if the strain rate +falls below the minimum value. Likewise, the stress +VARIABLE +DESCRIPTION +versus effective plastic strain curve for the highest value +of strain rate is used if the strain rate exceeds the maxi- +mum value. The strain rate parameters: C and P; the +curve ID, LCSR; EPS1 - EPS8 and ES1 - ES8 are ignored if +a Table ID is defined. +The strain rate values defined in the table may be given +as the natural logarithm of the strain rate. If the first +stress-strain curve in the table corresponds to a negative +strain rate, LS-DYNA assumes that the natural logarithm +of the strain rate value is used. Since the tables are inter- +nally discretized to equally space the points, natural +logarithms are necessary, for example, if the curves corre- +spond to rates from 10−4 to 104. +LCSR +Load curve ID defining strain rate scaling effect on yield stress. +EPPFR +𝜀rupture +, effective plastic strain at which material ruptures. +VP +Formulation for rate effects: +EQ.0.0: Scale yield stress (default), +EQ.1.0: Viscoplastic formulation. +LCDM +NUMINT +Optional curve ID defining nonlinear damage curve. To activate +the damage curve either the EPPF or EPPFR fields must contain +nonzero values. +Number of through thickness integration points which must fail +before a shell element is deleted. (If zero, all points must fail.) +The default of all integration points is not recommended since +shells undergoing large strain are often not deleted due to nodal +fiber rotations which limit strains at active integration points after +most points have failed. Better results are obtained if NUMINT is +set to 1 or a number less than one half of the number of through +thickness points. For example, if four through thickness points +are used, NUMINT should not exceed 2, even for fully integrated +shells which have 16 integration points. +EPS1 - EPS8 +Effective plastic strain values (optional if SIGY is defined). At +least 2 points should be defined. +ES1 - ES8 +Corresponding yield stress values to EPS1 - EPS8. +yield stress versus +effective plastic strain +for undamaged material +failure begins +nominal stress +after failure +damage, ω, increases +linearly with plastic +strain after failure +rupture +Figure M81-1. Stress strain behavior when damage is included + VARIABLE +DESCRIPTION +ALPHA +Parameter 𝛼. for the Rc-Dc model +BETA +Parameter 𝛽. for the Rc-Dc model +GAMMA +Parameter 𝛾. for the Rc-Dc model +D0 +B +Parameter 𝐷0. for the Rc-Dc model +Parameter 𝑏. for the Rc-Dc model +LAMBDA +Parameter 𝜆. for the Rc-Dc model +Parameter 𝐷𝑠. for the Rc-Dc model +Optional characteristic element length for this material. We +recommend that the default of 0 always be used, especially in +parallel runs. If zero, nodal values of the damage function are +used to compute the damage gradient. See discussion below. +DS +L +Remarks: +The stress strain behavior may be treated by a bilinear stress strain curve by defining +the tangent modulus, ETAN. Alternately, a curve similar to that shown in Figure M24-1 +is expected to be defined by (EPS1, ES1) - (EPS8, ES8); however, an effective stress +versus effective plastic strain curve (LCSS) may be input instead if eight points are +insufficient. The cost is roughly the same for either approach. The most general +approach is to use the table definition (LCSS) discussed below. +Three options to account for strain rate effects are possible: +1. Strain rate may be accounted for using the Cowper and Symonds model which +scales the yield stress with the factor +1 + ( +6⁄ +) +𝜀̇ +where 𝜀̇ is the strain rate, 𝜀̇ = √𝜀̇𝑖𝑗𝜀̇𝑖𝑗. +If the viscoplastic option is active, VP = 1.0, and if SIGY is > 0 then the dynamic +𝑝 ), which is +yield stress is computed from the sum of the static stress, 𝜎𝑦 +typically given by a load curve ID, and the initial yield stress, SIGY, multiplied +by the Cowper-Symonds rate term as follows: +𝑠(𝜀eff +𝜎𝑦(𝜀eff +𝑝 , 𝜀̇eff +𝑝 ) = 𝜎𝑦 +𝑠(𝜀eff +𝑝 ) + SIGY × +𝑝⁄ +𝜀̇eff +⎟⎞ +𝐶 ⎠ +⎜⎛ +⎝ +where the plastic strain rate is used. With this latter approach similar results +can be obtained between this model and material model: *MAT_ANISOTROP- +IC_VISCOPLASTIC. If SIGY = 0, the following equation is used instead where +𝑝 ), must be defined by a load curve: +the static stress, 𝜎𝑦 +𝑠(𝜀eff +𝜎𝑦(𝜀eff +𝑝 , 𝜀̇eff +𝑝 ) = 𝜎𝑦 +𝑝 ) +𝑠(𝜀eff +𝜀̇eff +⎟⎞ +𝐶 ⎠ +⎜⎛ +⎝ +⎡ +1 + +⎢⎢ +⎣ +𝑝⁄ +⎤ +⎥⎥ +⎦ +This latter equation is always used if the viscoplastic option is off. +2. For complete generality a load curve (LCSR) to scale the yield stress may be +input instead. In this curve the scale factor versus strain rate is defined. +3. +If different stress versus strain curves can be provided for various strain rates, +the option using the reference to a table (LCSS) can be used. Then the table +input in *DEFINE_TABLE is expected, see Figure M24-1. +The constitutive properties for the damaged material are obtained from the undamaged +material properties. The amount of damage evolved is represented by the constant, 𝜔, +which varies from zero if no damage has occurred to unity for complete rupture. For +uniaxial loading, the nominal stress in the damaged material is given by +𝜎nominal = +failure +Figure M81-2. A nonlinear damage curve is optional. Note that the origin of +the curve is at (0,0). It is permissible to input the failure strain EPPF as zero for +this option. The nonlinear damage curve is useful for controlling the softening +behavior after the failure strain is reached. +where P is the applied load and A is the surface area. The true stress is given by: +where 𝐴loss is the void area. The damage variable can then be defined: +𝜎true = +𝐴 − 𝐴loss +such that +𝜔 = +𝐴loss +0 ≤ 𝜔 ≤ 1. +In this model, unless LCDM is defined by the user, damage is defined in terms of +effective plastic strain after the failure strain is exceeded as follows: +𝑝 − 𝜀failure +𝜀eff +− 𝜀failure +𝜀rupture +𝑝 ≤ 𝜀rupture +𝜀failure +≤ 𝜀eff +𝜔 = +, +After exceeding the failure strain softening begins and continues until the rupture strain +is reached. +The Rc-Dc model is defined as: +The damage D is given by +where 𝜀𝑝 is the effective plastic strain, +𝐷 = ∫ 𝜔1𝜔2𝑑𝜀𝑝 +𝜔1 = ( +1 − 𝛾𝜎m +) +is a triaxial stress weighting term and +𝜔2 = (2 − 𝐴𝐷)𝛽 +is a asymmetric strain weighting term. In the above 𝜎m is the mean stress. For 𝐴𝐷 we +use +𝐴𝐷 = min (∣ +𝜎2 +𝜎3 +∣ , ∣ +𝜎3 +𝜎2 +∣) +where 𝜎𝑖 are the principal stresses and 𝜎1 > 𝜎2 > 𝜎3. Fracture is initiated when the +accumulation of damage is +where 𝐷𝑐 is the a critical damage given by +𝐷𝑐 +> 1 +A fracture fraction, +𝐷𝑐 = 𝐷0(1 + 𝑏|∇𝐷|𝜆) +𝐹 = +𝐷 − 𝐷𝑐 +𝐷𝑠 +defines the degradations of the material by the Rc-Dc model. +For the Rc-Dc model the gradient of damage needs to be estimated. The damage is +connected to the integration points, and, thus, the computation of the gradient requires +some manipulation of the LS-DYNA source code. Provided that the damage is +connected to nodes, it can be seen as a standard bilinear field and the gradient is easily +obtained. To enable this, the damage at the integration points are transferred to the +nodes as follows. Let 𝐸𝑛 be the set of elements sharing node 𝑛, 𝐸𝑛 the number of +elements in that set, 𝑃𝑒 the set of integration points in element 𝑒 and ∣𝑃𝑒∣ the number of +points in that set. The average damage 𝐷̅̅̅̅̅ 𝑒 in element 𝑒 is computed as +𝐷̅̅̅̅̅ 𝑒 = +∑ 𝐷𝑝 +𝑝∈𝑃𝑒 +∣𝑃𝑒∣ +where 𝐷𝑝 is the damage in integration point 𝑝. Finally, the damage value in node 𝑛 is +estimated as +𝐷𝑛 = +∑ 𝐷̅̅̅̅̅ 𝑒 +𝑒∈𝐸𝑛 +|𝐸𝑛| +. +This computation is performed in each time step and requires additional storage. +Currently we use three times the total number of nodes in the model for this calculation, +but this could be reduced by a considerable factor if necessary. There is an Rc-Dc +option for the Gurson dilatational-plastic model. In the implementation of this model, +𝑙 be the set of elements from +the norm of the gradient is computed differently. Let 𝐸𝑓 +𝑙 ∣ be the +within a distance 𝑙 of element, 𝑓 not including the element itself, and let ∣𝐸𝑓 +number of elements in that set. The norm of the gradient of damage is estimated +roughly as +‖∇𝐷‖𝑓 ≈ +𝑙 ∣ +∣𝐸𝑓 +∑ +𝑒∈𝐸𝑓 +∣𝐷𝑒 − 𝐷𝑓 ∣ +𝑑𝑒𝑓 +where 𝑑𝑒𝑓 is the distance between element 𝑓 and 𝑒. +The reason for taking the first approach is that it should be a better approximation of +the gradient, it can for one integration point in each element be seen as a weak gradient +of an elementwise constant field. The memory consumption as well as computational +work should not be much higher than for the other approach. +The RCDC1980 model is identical to the RCDC model except the expression for 𝐴𝐷is in +terms of the principal stress deviators and takes the form +𝐴𝐷 = max (∣ +𝑆2 +𝑆3 +∣ , ∣ +𝑆2 +𝑆1 +∣) +The STOCHASTIC option allows spatially varying yield and failure behavior. See *DE- +FINE_STOCHASTIC_VARIATION for additional information. +*DEFINE_MATERIAL_HISTORIES Properties +Label +Attributes +Description +Instability +Plastic Strain Rate +Damage +- +- +- +- +- +- +- +- +- +- +- +𝑝 , see EPPF +Failure indicator 𝜀eff +𝑝 +Effective plastic strain rate 𝜀̇eff +𝑝 /𝜀fail +- Damage 𝜔 +*MAT_FU_CHANG_FOAM_{OPTION} +This is Material Type 83. +Available options include: +DAMAGE_DECAY +LOG_LOG_INTERPOLATION +Rate effects can be modeled in low and medium density foams, see Figure M83-1. +Hysteretic unloading behavior in this model is a function of the rate sensitivity with the +most rate sensitive foams providing the largest hysteresis and vice versa. The unified +constitutive equations for foam materials by Chang [1995] provide the basis for this +model. The mathematical description given below is excerpted from the reference. +Further improvements have been incorporated based on work by Hirth, Du Bois, and +Weimar [1998]. Their improvements permit: load curves generated by drop tower test +to be directly input, a choice of principal or volumetric strain rates, load curves to be +defined in tension, and the volumetric behavior to be specified by a load curve. +The unloading response was generalized by Kolling, Hirth, Erhart and Du Bois [2006] to +allow the Mullin’s effect to be modeled, i.e., after the first loading and unloading, +further reloading occurs on the unloading curve. If it is desired to reload on the loading +curves with the new generalized unloading, the DAMAGE decay option is available +which allows the reloading to quickly return to the loading curve as the damage +parameter decays back to zero in tension and compression. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +KCON +F +5 +TC +F +6 +7 +8 +FAIL +DAMP +TBID +F +F +F +Default +none +none +none +none +1.E+20 +none +0.05 +none +Remarks +> > > ε +tensile +Optional Tensile Behavior +TFLAG = 1 +compressive +Nominal Strain +Default Tensile Behavior +TFLAG = 0 +Figure M83-1. Rate effects in the nominal stress versus engineering strain +curves, which are used to model rate effects in Fu Chang’s foam model. + Card 2 +1 +2 +3 +4 +5 +6 +7 +Variable +BVFLAG +SFLAG +RFLAG +TFLAG +PVID +SRAF +REF +Type +F +F +F +F +F +F +F +8 +HU +F +Default +1.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Remarks +1 +2 +3 +4 +Card 3 for DAMAGE_DECAY keyword option. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MINR +MAXR +SHAPE +BETAT +BETAC +Type +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +Card 3 for keyword option NOT set to DAMAGE_DECAY. + Card 3 +Variable +1 +D0 +Type +F +2 +N0 +F +3 +N1 +F +4 +N2 +F +5 +N3 +F +6 +C0 +F +7 +C1 +F +8 +C2 +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Card 4 for keyword option NOT set to DAMAGE_DECAY. + Card 4 +Variable +1 +C3 +Type +F +2 +C4 +F +3 +C5 +F +4 +AIJ +5 +SIJ +6 +7 +8 +MINR +MAXR +SHAPE +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +*MAT_FU_CHANG_FOAM + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EXPON +RIULD +Type +F +F +Default +1.0 +0.0 + VARIABLE +DESCRIPTION +MID +RO +E +KCON +TC +FAIL +DAMP +TBID +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus +Optional Young's modulus used in the computation of sound +speed. This will influence the time step, contact forces, hourglass +stabilization forces, and the numerical damping (DAMP). +EQ.0.0: KCON is set equal to the, +max(𝐸, current tangent to stresss-strain curve), +if TBID ≠ 0. Otherwise, if TBID = 0, KCON is set +equal to the maximum slope of the stress-strain curve. +Tension cut-off stress +Failure option after cutoff stress is reached: +EQ.0.0: tensile stress remains at cut-off value, +EQ.1.0: tensile stress is reset to zero. +Viscous +(0.05 < recommended value < 0.50; default is 0.05). +coefficient +model +to +damping +effects +Table ID, see *DEFINE_TABLE, for nominal stress vs. strain data +as a function of strain rate. If the table ID is provided, cards 3 and +4 may be left blank and the fit will be done internally. The Table +ID can be positive or negative . If TBID < 0, +enter |TBID| on the *DEFINE_TABLE keyword. +VARIABLE +DESCRIPTION +BVFLAG +Bulk viscosity activation flag, see Remark 1: +EQ.0.0: no bulk viscosity (recommended), +EQ.1.0: bulk viscosity active. +SFLAG +Strain rate flag : +EQ.0.0: true constant strain rate, +EQ.1.0: engineering strain rate. +RFLAG +Strain rate evaluation flag see Remark 3: +EQ.0.0: first principal direction, +EQ.1.0: principal strain rates for each principal direction, +EQ.2.0: volumetric strain rate. +TFLAG +Tensile stress evaluation: +EQ.0.0: linear in tension. +EQ.1.0: input via load curves with the tensile response +corresponds to negative values of stress and strain. +PVID +Optional load curve ID defining pressure versus volumetric +strain. See Remark 4. +SRAF +Strain rate averaging flag. See Remark 5. +LT.0.0: use exponential moving average. +EQ.0.0: use weighted running average. +EQ.1.0: average the last twelve values. +REF +HU +D0 +Use reference geometry to initialize the stress tensor. The +reference geometry is defined by the keyword: *INITIAL_- +FOAM_REFERENCE_GEOMETRY . +EQ.0.0: off, +EQ.1.0: on. +Hysteretic unloading factor between 0 and 1 (default = 0). See +also Remark 6 and Figure M83-4. +material constant, see equations below. +VARIABLE +N0 +N1 +N2 +N3 +C0 +C1 +C2 +C3 +C4 +C5 +AIJ, +SIJ +DESCRIPTION +material constant, see equations below. +material constant, see equations below. +material constant, see equations below. +material constant, see equations below. +material constant, see equations below. +material constant, see equations below. +material constant, see equations below. +material constant, see equations below. +material constant, see equations below. +material constant, see equations below. +material constant, see equations below. +material constant, see equations below. +MINR +Ratemin, minimum strain rate of interest. +MAXR +Ratemax, maximum strain rate of interest. +SHAPE +BETAT +BETAC +EXPON +Shape factor for unloading. Active for nonzero values of the +hysteretic unloading factor HU. Values less than one reduces the +energy dissipation and greater than one increases dissipation, see +also Figure M83-2. +Decay constant for damage in tension. The damage decays after +loading in ceases according to 𝑒−BETAT×𝑡. +Decay constant for damage in compression. The damage decays +after loading in ceases according to 𝑒−BETAC×𝑡. +Exponent for unloading. Active for nonzero values of the +hysteretic unloading factor HU. Default is 1.0 +RIULD +Flag for rate independent unloading, see Remark 6. +EQ.0.0: off, +EQ.1.0: on. +*MAT_083 +The strain is divided into two parts: a linear part and a non-linear part of the strain +and the strain rate becomes +𝐄(𝑡) = 𝐄𝐿(𝑡) + 𝐄𝑁(𝑡) +𝐄̇(𝑡) = 𝐄̇𝐿(𝑡) + 𝐄̇𝑁(𝑡) +where 𝐄̇𝑁 is an expression for the past history of 𝐄𝑁. A postulated constitutive equation +may be written as: +∞ +𝛔(𝑡) = ∫ [𝐄𝑡 +𝑁(𝜏), 𝐒(𝑡)] +𝑑𝜏 +where 𝐒(𝑡) is the state variable and ∫ +∞ and +𝜏=0 +∞ +.𝜏=0 is a functional of all values of 𝜏 in 𝑇𝜏: 0 ≤ 𝜏 ≤ +𝑁(𝜏) = 𝐄𝑁(𝑡 − 𝜏) +𝐄𝑡 +where 𝜏 is the history parameter: +𝑁(𝜏 = ∞) ⇔ the virgin material +𝐄𝑡 +It is assumed that the material remembers only its immediate past, i.e., a neighborhood +about 𝜏 = 0. Therefore, an expansion of 𝐄𝑡 +𝑁(𝜏) in a Taylor series about 𝜏 = 0 yields: +𝑁(𝜏) = 𝐄𝑁(0) + +𝐄𝑡 +∂𝐄𝑡 +∂𝑡 +(0)𝑑𝑡 +Hence, the postulated constitutive equation becomes: +𝛔(𝑡) = 𝛔∗[𝐄𝑁(𝑡), 𝐄̇𝑁(𝑡), 𝐒(𝑡)] +where we have replaced +∂𝐄𝑡 +∂𝑡 by 𝐄̇𝑁, and 𝛔∗ is a function of its arguments. +For a special case, +we may write +𝛔(𝑡) = 𝛔∗(𝐄𝑁(𝑡), 𝐒(𝑡)) +𝐄̇ +𝑁 = 𝑓 (𝐒(𝑡), 𝐬(𝑡)) +which states that the nonlinear strain rate is the function of stress and a state variable +which represents the history of loading. Therefore, the proposed kinetic equation for +foam materials is: +𝐄̇ +𝑁 = +‖𝛔‖ +𝐷0exp {−𝑐0 [ +𝛔: 𝐒 +(‖𝛔‖)2] +2𝑛0 +} +where 𝐷0, 𝑐0, and 𝑛0 are material constants, and 𝐒 is the overall state variable. If either +𝐷0 = 0 or 𝑐0 → ∞ then the nonlinear strain rate vanishes. +𝑆̇𝑖𝑗 = [𝑐1(𝑎𝑖𝑗𝑅 − 𝑐2𝑆𝑖𝑗)𝑃 + 𝑐3𝑊𝑛1(∥𝐄̇𝑁∥)𝑛2𝐼𝑖𝑗]𝑅 +𝑛3 +∥𝐄̇𝑁∥ +𝑐5 +− 1] +𝑅 = 1 + 𝑐4 [ +𝑃 = 𝛔: 𝐄̇𝑁 +𝑊 = ∫ 𝛔: (𝑑𝐄) +where c1, c2, c3, c4, c5, n1, n2, n3, and aij are material constants and: +2 +‖𝛔‖ = (𝜎𝑖𝑗𝜎𝑖𝑗) +∥𝐄̇∥ = (𝐸̇𝑖𝑗𝐸̇𝑖𝑗) +2 +∥𝐄̇𝑁∥ = (𝐸̇𝑁 +𝑖𝑗𝐸̇𝑁 +2 +𝑖𝑗) +In the implementation by Fu Chang the model was simplified such that the input +constants 𝑎𝑖𝑗 and the state variables 𝑆𝑖𝑗 are scalars. +Additional Remarks: +1. Bulk Viscosity. The bulk viscosity, which generates a rate dependent pressure, +may cause an unexpected volumetric response and consequently, it is optional +with this model. +2. Constant Velocity Loading. Dynamic compression tests at the strain rates of +interest in vehicle crash are usually performed with a drop tower. In this test +the loading velocity is nearly constant but the true strain rate, which depends +on the instantaneous specimen thickness, is not. Therefore, the engineering +strain rate input is optional so that the stress strain curves obtained at constant +velocity loading can be used directly. See the SFLAG field. +> > +Current State +Nominal Strain +Figure M83-2. HU=0, TBID>0 +3. Strain Rates with Multiaxial Loading. To further improve the response under +multiaxial loading, the strain rate parameter can either be based on the princi- +pal strain rates or the volumetric strain rate. See the RFLAG field. +4. Triaxial Loading. Correlation under triaxial loading is achieved by directly +inputting the results of hydrostatic testing in addition to the uniaxial data. +Without this additional information which is fully optional, triaxial response +tends to be underestimated. See the PVID field. +5. Strain Rate Averaging. Three different options are available. The default, +SRAF = 0.0, uses a weighted running average with a weight of 1/12 on the +current strain rate. With the second option, SRAF = 1.0, the last twelve strain +rates are averaged. The third option, SRAF < 0, uses an exponential moving +average with factor |SRAF| representing the degree of weighting decrease +(−1 ≤ SRAF < 0). The averaged strain rate at time 𝑡𝑛 is obtained by: +averaged = |SRAF|𝜀̇𝑛 + (1 − |SRAF|)𝜀̇𝑛−1 +𝜀̇𝑛 +averaged +6. Unloading Response Options. Several options are available to control +unloading response in MAT_083: +a) HU = 0 and TBID > 0. See Figure M83-2. +This is the old way. In this case the unloading response will follow the +curve with the lowest strain rate and is rate-independent. The curve +with lowest strain rate value (typically zero) in TBID should correspond +to the unloading path of the material as measured in a quasistatic test. +> > > ε +Current State +Nominal Strain +Figure M83-3. HU = 0, TBID < 0 +The quasistatic loading path then corresponds to a realistic (small) value +of the strain rate. +b) HU = 0 and TBID < 0 +In this case the curve with lowest strain rate value (typically zero) in +TBID must correspond to the unloading path of the material as meas- +ured in a quasistatic test. The quasistatic loading path then corresponds +to a realistic (small) value of the strain rate. At least three curves should +be used in the table (one for unloading, one for quasistatic, and one or +more for dynamic response). The quasistatic loading and unloading +path (thus the first two curves of the table) should form a closed loop. +The unloading response is given by a damage formulation for the prin- +cipal stresses as follows: +𝜎𝑖 = (1 − 𝑑)𝜎𝑖 +The damage parameter d is computed internally in such a way that the +unloading path under uniaxial tension and compression is fitted exactly +in the simulation. The unloading response is rate dependent in this case. +In some cases, this rate dependence for loading and unloading can lead +to noisy results. To reduce that noise, it is possible to switch to rate in- +dependent unloading with RIULD = 1. +> > > ε +Current State +Unloading curve computed +internally based on HU and SHAPE +Nominal Strain +Figure M83-4. HU > 0, TBID > 0 +c) HU > 0 and TBID > 0 +No unloading curve should be provided in the table and the curve with +the lowest strain rate value in TBID should correspond to the loading +path of the material as measured in a quasistatic test. At least two curves +should be used in the table (one for quasistatic and one or more for dy- +namic response). In this case the unloading response is given by a dam- +age formulation for the principal stresses as follows: +𝜎𝑖 = (1 − 𝑑)𝜎𝑖 +𝑑 = (1 − 𝐻𝑈) +⎢⎡1 − ( +⎣ +𝑊cur +𝑊max +SHAPE +EXPON +) +⎥⎤ +⎦ +where W corresponds to the current value of the hyperelastic energy per +unit undeformed volume. The unloading response is rate dependent in +this case. In some cases, this rate dependence for loading and unloading +can lead to noisy results. To reduce that noise, it is possible to switch to +rate independent unloading with RIULD = 1. +The LOG_LOG_INTERPOLATION option uses log-log interpolation for +table TBID in the strain rate direction. +*MAT_WINFRITH_CONCRETE +This is Material Type 84 with optional rate effects. The Winfrith concrete model is a +smeared crack (sometimes known as pseudo crack), smeared rebar model, implemented +in the 8-node single integration point continuum element, i.e., ELFORM = 1 in *SEC- +TION_SOLID. It is recommended that a double precision executable be used when +using this material model. Single precision may produce unstable results. +This model was developed by Broadhouse and Neilson [1987], and Broadhouse [1995] +over many years and has been validated against experiments. The input documenta- +tion given here is taken directly form the report by Broadhouse. The Fortran +subroutines and quality assurance test problems were also provided to LSTC by the +Winfrith Technology Center. +Rebar may be defined using the command *MAT_WINFRITH_CONCRETE_REIN- +FORCEMENT which appears in the following section. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F + Card 2 +Variable +Type +1 +E +F + Card 3 +1 +2 +YS +F +2 +3 +TM +F +3 +4 +PR +F +4 +5 +6 +UCS +UTS +F +5 +F +6 +7 +FE +F +7 +8 +ASIZE +F +8 +EH +UELONG +RATE +CONM +CONL +CONT +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +EPS1 +EPS2 +EPS3 +EPS4 +EPS5 +EPS6 +EPS7 +EPS8 +Type +F +F +F +F +F +F +F +Card 4 +Variable +1 +P1 +Type +F +2 +P2 +F +3 +P3 +F +4 +P4 +F +5 +P5 +F +6 +P6 +F +7 +P7 +F +8 +P8 +F + VARIABLE +DESCRIPTION +MID +RO +TM +PR +UCS +UTS +FE +Material identification. A unique number or label not exceeding +8 characters must be specified. +Mass density. +Initial tangent modulus of concrete. +Poisson's ratio. +Uniaxial compressive strength. +Uniaxial tensile strength. +Depends on value of RATE below. +RATE.EQ.0: Fracture energy (energy per unit area dissipated +in opening crack). +RATE.EQ.1: Crack width at which crack-normal tensile stress +goes to zero. +ASIZE +Aggregate size (radius). +E +YS +EH +Young's modulus of rebar. +Yield stress of rebar. +Hardening modulus of rebar +UEONG +Ultimate elongation before rebar fails. +RATE +Rate effects: +*MAT_WINFRITH_CONCRETE +DESCRIPTION +EQ.0.0: Strain rate effects are included. WARNING: energy +may not be conserved using this option. +EQ.1.0: Strain rate effects are turned off. Crack widths are +stored as extra history variables 30, 31, 32. +EQ.2.0: Like RATE = 1 but includes improved crack algorithm +(recommended). Crack widths are stored as extra his- +tory variables 3, 4, 5. +CONM +GT.0: Factor to convert model mass units to kg. +EQ.-1.: Mass, length, time units in model are lbf × sec2/in, +inch, sec. +EQ.-2.: Mass, length, time units in model are g, cm, microsec. +EQ.-3.: Mass, length, time units in model are g, mm, msec. +EQ.-4.: Mass, length, time units in model are metric ton, mm, +sec. +EQ.-5.: Mass, length, time units in model are kg, mm, msec. +CONL +CONM.GT.0: CONL is the conversion factor from model +length units to meters. +CONM.LE.0: CONL is ignored. +CONT +CONM.GT.0: CONL is the conversion factor from time units +to seconds +CONM.LE.0: CONT is ignored. +EPS1, EPS2, … +Volumetric strain values (natural logarithmic values), see +Remarks below. A maximum of 8 values are allowed. +P1, P2, … +Pressures corresponding to volumetric strain values given on +Card 3. +Remarks: +Pressure is positive in compression; volumetric strain is given by the natural log of the +relative volume and is negative in compression. The tabulated data are given in order +of increasing compression, with no initial zero point. +If the volume compaction curve is omitted, the following scaled curve is automatically +used where 𝑝1 is the pressure at uniaxial compressive failure from: +𝑝1 = +𝜎𝑐 +and 𝐾 is the bulk unloading modulus computed from +𝐾 = +𝐸𝑠 +3(1 − 2𝑣) +where 𝐸𝑠 is the input tangent modulus for concrete and 𝑣 is Poisson's ratio. +Volumetric Strain +Pressure +−𝑝1/𝐾 +−0.002 +−0.004 +−0.010 +−0.020 +−0.030 +−0.041 +−0.051 +−0.062 +−0.094 +1.00𝑝1 +1.50𝑝1 +3.00𝑝1 +4.80𝑝1 +6.00𝑝1 +7.50𝑝1 +9.45𝑝1 +11.55𝑝1 +14.25𝑝1 +25.05𝑝1 +Table M84-1. Default pressure versus volumetric strain +curve for concrete if the curve is not defined. +The Winfrith concrete model can generate an additional binary output database +containing information on crack locations, directions, and widths. In order to generate +the crack database, the LS-DYNA execution line is modified by adding: +where crf is the desired name of the crack database, e.g., q=d3crack. +q=crf +LS-PrePost can display the cracks on the deformed mesh plots. To do so, read the +d3plot database into LS-PrePost and then select File → Open → Crack from the top +menu bar. Or, open the crack database by adding the following to the LS-PrePost +execution line: +where crf is the name of the crack database, e.g., q=d3crack. +q=crf +By default, all the cracks in visible elements are shown. You can eliminate narrow +cracks from the display by setting a minimum crack width for displayed cracks. Do this +by choosing Settings → Post Settings → Concrete Crack Width. From the top menu bar +of LS-PrePost, choosing Misc → Model Info will reveal the number of cracked elements +and the maximum crack width in a given plot state. +An ASCII “aea_crack” output file is written if the command *DATABASE_BINARY_- +D3CRACK command is included in the input deck. This command does not have any +bearing on the aforementioned binary crack database. +*MAT_WINFRITH_CONCRETE_REINFORCEMENT +This is *MAT_084_REINF for rebar reinforcement supplemental to concrete defined +using Material type 84. Reinforcement may be defined in specific groups of elements, +but it is usually more convenient to define a two-dimensional mat in a specified layer of +a specified material. Reinforcement quantity is defined as the ratio of the cross- +sectional area of steel relative to the cross-sectional area of concrete in the element (or +layer). These cards may follow either one of two formats below and may also be +defined in any order. +Option 1 (Reinforcement quantities in element groups). + Card 1 +1 +2 +3 +Variable +EID1 +EID2 +INC +Type +I +I +I +4 +XR +F +5 +YR +F +6 +ZR +F +7 +8 +Option 2 (Two dimensional layers by part ID). Option 2 is active when first entry is left +blank. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID +AXIS +COOR +RQA +RQB +Type +blank +I +I +F +F +F + VARIABLE +DESCRIPTION +EID1 +EID2 +INC +XR +YR +ZR +First element ID in group. +Last element ID in group +Element increment for generation. +𝑥-reinforcement quantity (for bars running parallel to global 𝑥- +axis). +𝑦-reinforcement quantity (for bars running parallel to global 𝑦- +axis). +𝑧-reinforcement quantity (for bars running parallel to global 𝑧- +axis). +VARIABLE +PID +DESCRIPTION +Part ID of reinforced elements. If PID = 0, the reinforcement is +applied to all parts which use the Winfrith concrete model. +AXIS +Axis normal to layer. +EQ.1: A and B are parallel to global 𝑦 and 𝑧, respectively. +EQ.2: A and B are parallel to global 𝑥 and 𝑧, respectively. +EQ.3: A and B are parallel to global 𝑥 and 𝑦, respectively. +COOR +Coordinate location of layer: +AXIS.EQ.1: 𝑥-coordinate +AXIS.EQ.2: 𝑦-coordinate +AXIS.EQ.3: 𝑧-coordinate +RQA +RQB +Reinforcement quantity (A). +Reinforcement quantity (B). +Remarks: +1. Reinforcement quantity is the ratio of area of reinforcement in an element to the +element's total cross-sectional area in a given direction. This definition is true +for both Options 1 and 2. Where the options differ is in the manner in which it +is decided which elements are reinforced. In Option 1, the reinforced element +IDs are spelled out. In Option 2, elements of part ID PID which are cut by a +plane (layer) defined by AXIS and COOR are reinforced. +*MAT_ORTHOTROPIC_VISCOELASTIC +This is Material Type 86. It allows the definition of an orthotropic material with a +viscoelastic part. This model applies to shell elements. +NOTE: This material does not support specification of a ma- +terial angle, 𝛽𝑖, for each through-thickness integra- +tion point of a shell. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +Variable +1 +G0 +Type +F + Card 3 +1 +2 +RO +F +2 +3 +EA +F +3 +4 +EB +F +4 +5 +EC +F +5 +6 +VF +F +6 +7 +K +F +7 +8 +8 +GINF +BETA +PRBA +PRCA +PRCB +F +2 +F +3 +F +4 +F +5 +Variable +GAB +GBC +GCA +AOPT +MANGLE +Type +F + Card 4 +1 +F +2 +F +3 +Variable +Type +F +F +4 +A1 +F +5 +A2 +F +7 +8 +7 +8 +F +6 +6 +A3 +Variable +1 +V1 +Type +F + VARIABLE +MID +*MAT_ORTHOTROPIC_VISCOELASTIC +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +EA +EB +EC +VF +K +G0 +GINF +BETA +PRBA +PRCA +PRCB +GAB +GBC +GCA +AOPT +Mass density +Young’s Modulus 𝐸𝑎 +Young’s Modulus 𝐸𝑏 +Young’s Modulus 𝐸𝑐 +Volume fraction of viscoelastic material +Elastic bulk modulus +𝐺0, short-time shear modulus +𝐺∞, long-time shear modulus +𝛽, decay constant +Poisson’s ratio, 𝜈𝑏𝑎 +Poisson’s ratio, 𝜈𝑐𝑎 +Poisson’s ratio, 𝜈𝑐𝑏 +Shear modulus, 𝐺𝑎𝑏 +Shear modulus, 𝐺𝑏𝑐 +Shear modulus, 𝐺𝑐𝑎 +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +VARIABLE +DESCRIPTION +NATE_NODES, and then rotated about the shell ele- +ment normal by an angle MANGLE. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_ECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, MANGLE, from a line in the plane of the el- +ement defined by the cross product of the vector 𝐯 with +the element normal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +MANGLE +Material angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA. +A1 A2 A3 +Define components of vector 𝐚 for AOPT = 2. +V1 V2 V3 +Define components of vector 𝐯 for AOPT = 3. +D1 D2 D3 +Define components of vector 𝐝 for AOPT = 2. +Remarks: +For the orthotropic definition it is referred to Material Type 2 and 21. +*MAT_CELLULAR_RUBBER +This is Material Type 87. This material model provides a cellular rubber model with +confined air pressure combined with linear viscoelasticity as outlined by Christensen +[1980]. See Figure M87-1. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +PR +F +4 +N +I +5 +6 +7 +8 +Card 2 if N > 0, a least squares fit is computed from uniaxial data + Card 2 +1 +Variable +SGL +2 +SW +Type +F +F +3 +ST +F +4 +5 +6 +7 +8 +LCID +F +Card 2 if N = 0, define the following constants + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +C10 +C01 +C11 +C20 +C02 +Type +F + Card 3 +Variable +1 +P0 +F +2 +PHI +F +3 +IVS +Type +F +F +F + VARIABLE +MID +6 +7 +8 +F +4 +G +F +F +5 +BETA +F +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +VARIABLE +DESCRIPTION +PR +N +Poisson’s ratio, typical values are between .0 to .2. Due to the +large compressibility of air, large values of Poisson’s ratio +generates physically meaningless results. +Order of fit (currently < 3). If n > 0 then a least square fit is +computed with uniaxial data. The parameters given on card 2 +should be specified. Also see *MAT_MOONEY_RIVLIN_RUB- +BER (material model 27). A Poisson’s ratio of .5 is assumed for +the void free rubber during the fit. The Poisson’s ratio defined +on Card 1 is for the cellular rubber. A void fraction formulation is +used. +Define, if N > 0: +SGL +SW +ST +LCID +Define, if N = 0: +C10 +C01 +C11 +C20 +C02 +P0 +PHI +IVS +G +Specimen gauge length l0 +Specimen width +Specimen thickness +Load curve ID giving the force versus actual change ΔL in the +gauge length. If SGL, SW, and ST are set to unity (1.0), then curve +LCID is also engineering stress versus engineering strain. +Coefficient, C10 +Coefficient, C01 +Coefficient, C11 +Coefficient, C20 +Coefficient, C02 +Initial air pressure, P0 +Ratio of cellular rubber to rubber density, Φ +Initial volumetric strain, γ +0 +Optional shear relaxation modulus, 𝐺, for rate effects (viscosity) +BETA +Optional decay constant, 𝛽1 +Rubber Block with Entrapped Air +Air +Figure M87-1. Cellular rubber with entrapped air. By setting the initial air +pressure to zero, an open cell, cellular rubber can be simulated. +Remarks: +Rubber is generally considered to be fully incompressible since the bulk modulus +greatly exceeds the shear modulus in magnitude. To model the rubber as an +unconstrained material a hydrostatic work term, 𝑊𝐻(𝐽), is included in the strain energy +functional which is function of the relative volume, 𝐽, [Ogden 1984]: +𝑊(𝐽1, 𝐽2, 𝐽) = ∑ 𝐶𝑝𝑞(𝐽1 − 3)𝑝 +𝑝,𝑞=0 +(𝐽2 − 3)𝑞 + 𝑊𝐻(𝐽) +𝐽1 + 𝐼1𝐼3 +𝐽2 + 𝐼2𝐼3 +−1 +3⁄ +−2 +3⁄ +In order to prevent volumetric work from contributing to the hydrostatic work the first +and second invariants are modified as shown. This procedure is described in more +detail by Sussman and Bathe [1987]. +The effects of confined air pressure in its overall response characteristics is included by +augmenting the stress state within the element by the air pressure. +𝜎𝑖𝑗 = 𝜎𝑖𝑗 +𝑠𝑘 − 𝛿𝑖𝑗𝜎 air +𝑠𝑘 is the bulk skeletal stress and 𝜎 𝑎𝑖𝑟 is the air pressure computed from the +where 𝜎𝑖𝑗 +equation: +𝜎 air = − +𝑝0𝛾 +1 + 𝛾 − 𝜙 +where p0 is the initial foam pressure usually taken as the atmospheric pressure and γ +defines the volumetric strain +𝛾 = 𝑉 − 1 + 𝛾0 +where V is the relative volume of the voids and γ0 is the initial volumetric strain which +is typically zero. The rubber skeletal material is assumed to be incompressible. +Rate effects are taken into account through linear viscoelasticity by a convolution +integral of the form: +𝜎𝑖𝑗 = ∫ 𝑔 𝑖𝑗𝑘𝑙 +(𝑡 − 𝜏) +∂𝜀𝑘𝑙 +∂𝜏 +𝑑𝜏 +or in terms of the second Piola-Kirchhoff stress, 𝑆𝑖𝑗, and Green's strain tensor, 𝐸𝑖𝑗, +𝑆𝑖𝑗 = ∫ 𝐺 𝑖𝑗𝑘𝑙 +(𝑡 − 𝜏) +∂𝜀𝑘𝑙 +∂𝜏 +𝑑𝜏 +(𝑡 − 𝜏) and 𝐺 𝑖𝑗𝑘𝑙 +where 𝑔 𝑖𝑗𝑘𝑙 +measures. This stress is added to the stress tensor determined from the strain energy +functional. +(𝑡 − 𝜏)are the relaxation functions for the different stress +Since we wish to include only simple rate effects, the relaxation function is represented +by one term from the Prony series: +𝑔(𝑡) = 𝛼0 + ∑ 𝛼𝑚𝑒−𝛽𝑡 +𝑚=1 +given by, +𝑔(𝑡) = 𝐸𝑑𝑒−𝛽1𝑡. +This model is effectively a Maxwell fluid which consists of a damper and spring in +series. We characterize this in the input by a shear modulus, 𝐺, and decay constant, 𝛽1. +The Mooney-Rivlin rubber model (model 27) is obtained by specifying n = 1 without air +pressure and viscosity. In spite of the differences in formulations with Model 27, we +find that the results obtained with this model are nearly identical with those of material +type 27 as long as large values of Poisson’s ratio are used. +*MAT_MTS +This is Material Type 88. The MTS model is due to Mauldin, Davidson, and Henninger +[1990] and is available for applications involving large strains, high pressures and strain +rates. As described in the foregoing reference, this model is based on dislocation +mechanics and provides a better understanding of the plastic deformation process for +ductile materials by using an internal state variable call the mechanical threshold stress. +This kinematic quantity tracks the evolution of the material’s microstructure along +some arbitrary strain, strain rate, and temperature-dependent path using a differential +form that balances dislocation generation and recovery processes. Given a value for the +mechanical threshold stress, the flow stress is determined using either a thermal- +activation-controlled or a drag-controlled kinetics relationship. An equation-of-state is +required for solid elements and a bulk modulus must be defined below for shell +elements. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +4 +5 +6 +7 +8 +SIGA +SIGI +SIGS +SIG0 +BULK +F +3 +F +4 +F +5 +F +6 +F +7 +8 +Variable +HF0 +HF1 +HF2 +SIGS0 +EDOTS0 +BURG +CAPA +BOLTZ +Type +F + Card 3 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +SM0 +SM1 +SM2 +EDOT0 +GO +PINV +QINV +EDOTI +Type +F + Card 4 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +G0I +PINVI +QINVI +EDOTS +G0S +PINVS +QINVS +Type +F +F +F +F +F +F +Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RHOCPR +TEMPRF +ALPHA +EPS0 +Type +F +F + VARIABLE +DESCRIPTION +MID +RO +SIGA +SIGI +SIGS +SIG0 +HF0 +HF1 +HF2 +SIGS0 +BULK +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +𝜎̂𝑎, dislocation interactions with long-range barriers (force/area). +𝜎̂𝑖, dislocation interactions with interstitial atoms (force/area). +𝜎̂𝑠, dislocation interactions with solute atoms (force/area). +𝜎̂0, initial value of 𝜎̂ at zero plastic strain (force/area) NOT USED. +𝑎0, dislocation generation material constant (force/area). +𝑎1, dislocation generation material constant (force/area). +𝑎2, dislocation generation material constant (force/area). +𝜎̂εso, saturation threshold stress at 0o K (force/area). +Bulk modulus defined for shell elements only. Do not input for +solid elements. +EDOTS0 +𝜀̇εso, reference strain-rate (time-1). +BURG +Magnitude of Burgers vector +(distance) +(interatomic slip distance), +CAPA +Material constant, A. +BOLTZ +Boltzmann’s constant, k (energy/degree). +SM0 +SM1 +𝐺0, shear modulus at zero degrees Kelvin (force/area). +𝑏1, shear modulus constant (force/area). +DESCRIPTION +*MAT_MTS +SM2 +𝑏2, shear modulus constant (degree). +EDOT0 +𝜀̇𝑜, reference strain-rate (time-1). +G0 +PINV +QINV +𝑔0, normalized activation energy for a dislocation/dislocation +interaction. +𝑝, material constant. +𝑞, material constant. +EDOTI +𝜀̇𝑜,𝑖, reference strain-rate (time-1). +G0I +PINVI +QINVI +𝑔0,𝑖, normalized activation energy for a dislocation/interstitial +interaction. +𝑝𝑖 +𝑞𝑖 +, material constant. +, material constant. +EDOTS +𝜀̇𝑜,𝑠, reference strain-rate (time-1). +G0S +PINVS +QINVS +𝑔0,𝑠 normalized activation energy for a dislocation/solute +interaction. +𝑝𝑠 +𝑞𝑠 +, material constant. +, material constant. +RHOCPR +𝜌𝑐𝑝, product of density and specific heat. +TEMPRF +𝑇ref, initial element temperature in degrees K. +ALPHA +𝛼, material constant (typical value is between 0 and 2). +EPS0 +𝜀𝑜, factor to normalize strain rate in the calculation of Θ𝑜. (time-1). +Remarks: +The flow stress 𝜎 is given by: +𝜎 = 𝜎̂𝑎 + +𝐺0 +[𝑠th𝜎̂ + 𝑠th,𝑖𝜎̂𝑖 + 𝑠th,𝑠𝜎̂𝑠] +The first product in the equation for 𝜏 contains a micro-structure evolution variable, +i.e.,𝜎̂ , called the Mechanical Threshold Stress (MTS), that is multiplied by a constant- +structure deformation variable s𝑡ℎ: s𝑡ℎ is a function of absolute temperature T and the +plastic strain-rates 𝜀̇p. The evolution equation for 𝜎̂ is a differential hardening law +representing dislocation-dislocation interactions: +∂ +∂𝜀𝑝 ≡ Θ𝑜 +⎡ +⎢⎢ +1 − +⎢ +⎣ +tanh (𝛼 𝜎̂ +𝜎̂𝜀𝑠 +tanh(𝛼) +) +⎤ +⎥⎥ +⎥ +⎦ +The term, ∂𝜎̂ +∂𝜀𝑝, represents the hardening due to dislocation generation and the stress +ratio, 𝜎̂ +, represents softening due to dislocation recovery. The threshold stress at zero +𝜎̂𝜀𝑠 +strain-hardening 𝜎̂𝜀𝑠 is called the saturation threshold stress. Relationships for Θ𝑜, 𝜎̂𝜀𝑠 +are: +Θ𝑜 = 𝑎𝑜 + 𝑎1ln ( +𝜀̇𝑝 +𝜀0 +) + 𝑎2√ +𝜀̇𝑝 +𝜀0 +which contains the material constants, 𝑎𝑜, 𝑎1, and 𝑎2. The constant, 𝜎̂𝜀𝑠, is given as: +𝜎̂εs = 𝜎̂εso ( +𝑘𝑇/𝐺𝑏3𝐴 +) +𝜀̇𝑝 +𝜀̇εso +which contains the input constants: 𝜎̂𝜀𝑠𝑜, 𝜀̇𝜀𝑠𝑜, 𝑏, A, and k. The shear modulus G +appearing in these equations is assumed to be a function of temperature and is given by +the correlation. +𝐺 = 𝐺0 − 𝑏1 (𝑒𝑏2 𝑇⁄ − 1) +⁄ +which contains the constants: 𝐺0, 𝑏1, and 𝑏2. For thermal-activation controlled +deformation 𝑠𝑡ℎ is evaluated via an Arrhenius rate equation of the form: +⎧ +{{{ +⎨ +{{{ +⎩ +The absolute temperature is given as: +𝑠𝑡ℎ = +1 − +⎡𝑘𝑇ln ( +⎢⎢⎢ +⎣ +𝐺𝑏3𝑔0 +𝜀̇0 +𝜀̇𝑝) +⎤ +⎥⎥⎥ +⎦ +⎫ +}}} +⎬ +}}} +⎭ +where E is the internal energy density per unit initial volume. +𝑇 = 𝑇ref + +𝜌𝑐𝑝 +*MAT_PLASTICITY_POLYMER +This is Material Type 89. An elasto-plastic material with an arbitrary stress versus +strain curve and arbitrary strain rate dependency can be defined. It is intended for +applications where the elastic and plastic sections of the response are not as clearly +distinguishable as they are for metals. Rate dependency of failure strain is included. +Many polymers show a more brittle response at high rates of strain. +5 +6 +7 +8 + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +Default +none +none +none +none + Card 2 +Variable +Type +Default +1 +C +F +0 + Card 3 +1 +2 +P +F +0 +2 +3 +4 +5 +6 +7 +8 +LCSS +LCSR +F +0 +3 +F +0 +4 +5 +6 +7 +8 +Variable +EFTX +DAMP +RFAC +LCFAIL +Type +Default +F +0 +F +0 +F +0 +F +0 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +VARIABLE +DESCRIPTION +E +PR +C +P +Young’s modulus. +Poisson’s ratio. +Strain rate parameter, 𝐶, (Cowper Symonds). +Strain rate parameter, 𝑃, (Cowper Symonds). +LCSS +Curve ID or Table ID. +1. Case 1: LCSS is a curve ID. The curve defines effective +stress as a function of total effective strain. +2. Case 2: LCSS is a table ID. Each strain rate value in the +table is associated to a curve ID giving the stress as a +function of effective strain for that rate. +The strain rate values defined in the table may be given +as the natural logarithm of the strain rate. If the first +stress-strain curve in the table corresponds to a negative +strain rate, LS-DYNA assumes that the natural logarithm +of the strain rate value is used. Since the tables are inter- +nally discretized to equally space the points, natural +logarithms are necessary, for example, if the curves corre- +spond to rates from 10−4 to 104. +LCSR +Load curve ID defining strain rate scaling effect on yield stress. If +LCSR is negative, the load curve is evaluated using a binary +search for the correct interval for the strain rate. The binary +search is slower than the default incremental search, but in cases +where large changes in the strain rate may occur over a single +time step, it is more robust. +EFTX +Failure flag. +EQ.0.0: failure determined by maximum tensile strain (default), +EQ.1.0: failure determined only by tensile strain in local 𝑥 +direction, +EQ.2.0: failure determined only by tensile strain in local 𝑦 +direction. +DAMP +Stiffness-proportional damping ratio. Typical values are 10−3 or +10−4. If set too high instabilities can result. +Filtering factor for strain rate effects. Must be between 0 (no +filtering) and 1 (infinite filtering). The filter is a simple low pass +filter to remove high frequency oscillation from the strain rates +before they are used in rate effect calculations. The cut off +frequency of the filter is [(1 - RFAC) / timestep] rad/sec. +Load curve ID giving variation of failure strain with strain rate. +The points on the 𝑥-axis should be natural log of strain rate, the 𝑦- +axis should be the true strain to failure. Typically this is +measured by uniaxial tensile test, and the strain values converted +to true strain. +*MAT_089 + VARIABLE +RFAC +LCFAIL +Remarks: +1. M89 vs. M24. MAT_089 is the same as MAT_024 except for the following +points: +• Load curve lookup for yield stress is based on equivalent uniaxial strain, +not plastic strain (Remarks 2 and 3) +• elastic stiffness is initially equal to 𝐸 but will be increased according to the +slope of the stress-strain curve (Remark 7) +• special strain calculation used for failure and damage (Remark 2) +• failure strain depends on strain rate (Remark 4) +2. Strain Calculation for Failure and Damage. The strain used for failure and +damage calculation, 𝜀pm is based on an approximation of the greatest value of +maximum principal strain encountered during the analysis: +𝜀pm = max +i≤n +where +𝑛 = current time step index +(𝜀𝐻 +𝑖 + 𝜀VM +) +max +𝑖≤𝑛 +(. . . ) = maximum value attained by the argument during the calculation +𝜀𝐻 = +𝜀𝑥 + 𝜀𝑦 + 𝜀𝑧 +𝜀𝑥, 𝜀𝑦, 𝜀𝑧 = cumulative strain in the local x, y, or z direction +𝜀vm = √ +tr(𝛆′T𝛆′), the usual definition of equivalent uniaxial strain +𝛆′ = deviatoric strain tensor, where each 𝜀𝑥, 𝜀𝑦, and 𝜀𝑧 is cumulative +3. Yield Stress Load Curves. When looking up yield stress from the load curve +LCSS, the 𝑥-axis value is 𝜀vm. +4. Failure Strain Load Curves. +𝜀sr = +d𝜀pm +d𝑡 += strain rate for failure and damage calculation +𝜀𝐹 = LCFAIL(𝜀𝑠𝑟) += Instantanous true strain to failure from look-up on the curve LCFAIL +5. Damage. A damage approach is used to avoid sudden shocks when the failure +strain is reached. Damage begins when the "strain ratio," 𝑅, reaches 1.0, where +𝑅 = ∫ +𝑑𝜀pm +𝜀𝐹 +. +Damage is complete, and the element fails and is deleted, when 𝑅 = 1.1. The +damage, +𝐷 = +{⎧1.0 +⎩{⎨ +10(1.1 − 𝑅) 1.0 < 𝑅 < 1.1 + 𝑅 < 1.0 +is a reduction factor applied to all stresses, for example, when 𝑅 = 1.05, then +𝐷 = 0.5. +6. Strain Definitions. Unlike other LS-DYNA material models, both the input +stress-strain curve and the strain to failure are defined as total true strain, not +plastic strain. The input can be defined from uniaxial tensile tests; nominal +stress and nominal strain from the tests must be converted to true stress and +true strain. The elastic component of strain must not be subtracted out. +7. Elastic Stiffness Scaling. The stress-strain curve is permitted to have sections +steeper (i.e. stiffer) than the elastic modulus. When these are encountered the +elastic modulus is increased to prevent spurious energy generation. The elastic +stiffness is scaled by a factor 𝑓e, which is calculated as follows: +𝑓𝑒 = max (1.0, +𝑠max +3𝐺 +) +where +𝐺 = initial shear modulus +𝑆max = maximum slope of stress-strain curve encountered during the analysis +8. Precision. Double precision is recommended when using this material model, +especially if the strains become high. +9. Shell Numbering. Invariant shell numbering is recommended when using this +material model. See *CONTROL_ACCURACY. +*MAT_ACOUSTIC +This is Material Type 90. This model is appropriate for tracking low pressure stress +waves in an acoustic media such as air or water and can be used only with the acoustic +pressure element formulation. The acoustic pressure element requires only one +unknown per node. This element is very cost effective. Optionally, cavitation can be +allowed. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F + Card 2 +Variable +1 +XP +Type +F +2 +YP +F +3 +C +F +3 +ZP +F +4 +BETA +F +4 +XN +F +5 +CF +F +5 +YN +F +6 +7 +8 +ATMOS +GRAV +F +7 +8 +F +6 +ZN +F + VARIABLE +DESCRIPTION +MID +RO +C +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Sound speed +BETA +Damping factor. Recommend values are between 0.1 and 1.0. +CF +Cavitation flag: +EQ.0.0: off, +EQ.1.0: on. +ATMOS +Atmospheric pressure (optional) +GRAV +Gravitational acceleration constant (optional) +XP +YP +2-484 (EOS) +x-coordinate of free surface point +VARIABLE +DESCRIPTION +ZP +XN +YN +ZN +z-coordinate of free surface point +x-direction cosine of free surface normal vector +y-direction cosine of free surface normal vector +z-direction cosine of free surface normal vector +*MAT_091-092 +*MAT_SOFT_TISSUE_{OPTION} +Available options include: + +VISCO +*MAT_SOFT_TISSUE +This is Material Type 91 (OPTION=) or Material Type 92 (OPTION = VISCO). +This material is a transversely isotropic hyperelastic model for representing biological +soft tissues such as ligaments, tendons, and fascia. The representation provides an +isotropic Mooney-Rivlin matrix reinforced by fibers having a strain energy contribution +with the qualitative material behavior of collagen. The model has a viscoelasticity +option which activates a six-term Prony series kernel for the relaxation function. In this +case, the hyperelastic strain energy represents the elastic (long-time) response. See +Weiss et al. [1996] and Puso and Weiss [1998] for additional details. +NOTE: This material does not support specification of a ma- +terial angle, 𝛽𝑖, for each through-thickness integra- +tion point of a shell. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +Variable +1 +XK +2 +RO +F +2 +3 +C1 +F +3 +4 +C2 +F +4 +5 +C3 +F +5 +6 +C4 +F +6 +7 +C5 +F +7 +XLAM +FANG +XLAM0 +FAILSF +FAILSM +FAILSHR +Type +F +F +F +F +F +F +F + Card 3 +1 +Variable +AOPT +Type +F +2 +AX +F +3 +AY +F +4 +AZ +F +5 +BX +F +6 +BY +F +7 +BZ +F +8 +8 +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LA1 +LA2 +LA3 +MACF +Type +F +F +F +I +Prony Series Card 1. Additional card for VISCO keyword option. + Card 5 +Variable +1 +S1 +Type +F +2 +S2 +F +3 +S3 +F +4 +S4 +F +5 +S5 +F +6 +S6 +F +Prony Series Card 2. Additional card for VISCO keyword option. + Card 6 +Variable +1 +T1 +Type +F +2 +T2 +F +3 +T3 +F +4 +T4 +F +5 +T5 +F +6 +T6 +F +7 +8 +7 +8 + VARIABLE +MID +DESCRIPTION +Material identification. +exceeding 8 characters must be specified. + A unique number or label not +RO +Mass density +C1 - C5 +Hyperelastic coefficients +XK +Bulk Modulus +XLAM +FANG +Stretch ratio at which fibers are straightened +Fiber angle in local shell coordinate system (shells only) +XLAM0 +Initial fiber stretch (optional) +FAILSF +Stretch ratio for ligament fibers at failure (applies to shell +elements only). If zero, failure is not considered. +VARIABLE +FAILSM +FAILSHR +DESCRIPTION +Stretch ratio for surrounding matrix material at failure (applies +to shell elements only). If zero, failure is not considered. +Shear strain at failure at a material point (applies to shell +elements only). If zero, failure is not considered. This failure +value is independent of FAILSF and FAILSM. +AOPT +Material axes option, see Figure M2-1 (bricks only): +EQ.0.0: locally orthotropic with material axes determined by +element nodes as shown in Figure M2-1. Nodes 1, 2, +and 4 of an element are identical to the nodes used +for the definition of a coordinate system as by *DE- +FINE_COORDINATE_NODES. +EQ.1.0: locally orthotropic with material axes determined by +a point in space and the global location of the ele- +ment center; this is the 𝑎-direction. This option is for +solid elements only. +EQ.2.0: globally orthotropic with material axes determined +by vectors defined below, as with *DEFINE_COOR- +DINATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by a +line in the plane of the element defined by the cross +product of the vector 𝐯 with the element normal. +The plane of a solid element is the midsurface be- +tween the inner surface and outer surface defined by +the first four nodes and the last four nodes of the +connectivity of the element, respectively. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector 𝐯, and +an originating point, 𝐩, which define the centerline +axis. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system +ID number (CID on *DEFINE_COORDINATE_- +or +NODES, +*DEFINE_COORDINATE_VECTOR). Available in +R3 version of 971 and later. +*DEFINE_COORDINATE_SYSTEM +AX, AY, AZ +Equal to XP, YP, ZP for AOPT = 1, +Equal to A1, A2, A3 for AOPT = 2, +Equal to V1, V2, V3 for AOPT = 3 or 4. +VARIABLE +BX, BY, BZ +DESCRIPTION +Equal to D1, D2, D3 for AOPT = 2 +Equal to XP, YP, ZP for AOPT = 4 +LAX, LAY, LAZ +Local fiber orientation vector (bricks only) +MACF +Material axes change flag for brick elements: +EQ.1: No change, default, +EQ.2: switch material axes 𝑎 and 𝑏, +EQ.3: switch material axes 𝑎 and 𝑐, +EQ.4: switch material axes 𝑏 and 𝑐. +Factors in the Prony series. +Characteristic times for Prony series relaxation kernel for +VISCO option. +S1 – S6 +T1 - T6 +Remarks: +The overall strain energy 𝑊 is "uncoupled" and includes two isotropic deviatoric matrix +terms, a fiber term 𝐹, and a bulk term: +𝑊 = 𝐶1(𝐼 ̃1 − 3) + 𝐶2(𝐼 ̃2 − 3) + 𝐹(𝜆) + +𝐾[ln(𝐽)]2 +Here, 𝐼 ̃1 and 𝐼 ̃2 are the deviatoric invariants of the right Cauchy deformation tensor, 𝜆 is +the deviatoric part of the stretch along the current fiber direction, and 𝐽 = det𝐅 is the +volume ratio. The material coefficients 𝐶1 and 𝐶2 are the Mooney-Rivlin coefficients, +while K is the effective bulk modulus of the material (input parameter XK). +The derivatives of the fiber term 𝐹 are defined to capture the behavior of crimped +collagen. The fibers are assumed to be unable to resist compressive loading - thus the +model is isotropic when 𝜆 < 1. An exponential function describes the straightening of +the fibers, while a linear function describes the behavior of the fibers once they are +straightened past a critical fiber stretch level 𝜆 ≥ 𝜆∗ (input parameter XLAM): +∂𝐹 +∂𝜆 += +⎧ +{{{{ +{{{{ +⎨ +⎩ +𝐶3 +𝜆 < 1 +[exp(𝐶4(𝜆 − 1)) − 1] 𝜆 < 𝜆∗ +(𝐶5𝜆 + 𝐶6) +𝜆 ≥ 𝜆∗ +Coefficients 𝐶3, 𝐶4, and 𝐶5 must be defined by the user. 𝐶6 is determined by LS-DYNA +to ensure stress continuity at 𝜆 = 𝜆∗. Sample values for the material coefficients 𝐶1 − 𝐶5 +and 𝜆∗ for ligament tissue can be found in Quapp and Weiss [1998]. The bulk modulus +𝐾 should be at least 3 orders of magnitude larger than 𝐶1 to ensure near-incompressible +material behavior. +Viscoelasticity is included via a convolution integral representation for the time- +dependent second Piola-Kirchoff stress 𝐒(𝐂, 𝑡): +𝐒(𝐂, 𝑡) = 𝐒𝑒(𝐂) + ∫ 2𝐺(𝑡 − 𝑠) +𝜕𝑊 +𝜕𝐂(𝑠) +𝑑𝑠 +Here, 𝐒𝑒 is the elastic part of the second PK stress as derived from the strain energy, and +𝐺(𝑡 − 𝑠) is the reduced relaxation function, represented by a Prony series: +𝐺(𝑡) = ∑ 𝑆𝑖exp ( +𝑖=1 +𝑇𝑖 +) +Puso and Weiss [1998] describe a graphical method to fit the Prony series coefficients to +relaxation data that approximates the behavior of the continuous relaxation function +proposed by Y-C. Fung, as quasilinear viscoelasticity. +Remarks on Input Parameters: +Cards 1 through 4 must be included for both shell and brick elements, although for +shells cards 3 and 4 are ignored and may be blank lines. +For shell elements, the fiber direction lies in the plane of the element. The local axis is +defined by a vector between nodes n1 and n2, and the fiber direction may be offset from +this axis by an angle FANG. +For brick elements, the local coordinate system is defined using the convention +described previously for *MAT_ORTHOTROPIC_ELASTIC. The fiber direction is +oriented in the local system using input parameters LAX, LAY, and LAZ. By default, +(LAX, LAY, LAZ) = (1,0,0) and the fiber is aligned with the local x-direction. +An optional initial fiber stretch can be specified using XLAM0. The initial stretch is +applied during the first time step. This creates preload in the model as soft tissue +contacts and equilibrium is established. For example, a ligament tissue "uncrimping +strain" of 3% can be represented with initial stretch value of 1.03. +If the VISCO option is selected, at least one Prony series term (S1, T1) must be defined. +*MAT_ELASTIC_6DOF_SPRING_DISCRETE_BEAM +This is Material Type 93. This material model is defined for simulating the effects of +nonlinear elastic and nonlinear viscous beams by using six springs each acting about +one of the six local degrees-of-freedom. The input consists of part ID's that reference +material type, *MAT_ELASTIC_SPRING_DISCRETE_BEAM above (type 74 above). +Generally, these referenced parts are used only for the definition of this material model +and are not referenced by any elements. The two nodes defining a beam may be +coincident to give a zero length beam, or offset to give a finite length beam. For finite +length discrete beams the absolute value of the variable SCOOR in the SECTION_- +BEAM input should be set to a value of 2.0, which causes the local r-axis to be aligned +along the two nodes of the beam to give physically correct behavior. The distance +between the nodes of a beam should not affect the behavior of this material model. A +triad is used to orient the beam for the directional springs. + Card 1 +1 +Variable +MID +2 +RO +3 +4 +5 +6 +7 +8 +TPIDR +TPIDS +TPIDT +RPIDR +RPIDS +RPIDT +Type +A8 +F +I +I +I +I +I +I + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density, see also volume in *SECTION_BEAM definition. +TPIDR +TPIDS +TPIDT +RPIDR +RPIDS +Translational motion in the local r-direction is governed by part +ID TPIDR. If zero, no force is computed in this direction. +Translational motion in the local s-direction is governed by part +ID TPIDS. If zero, no force is computed in this direction. +Translational motion in the local t-direction is governed by part +ID TPIDT. If zero, no force is computed in this direction. +Rotational motion about the local r-axis is governed by part ID +RPIDR. If zero, no moment is computed about this axis. +Rotational motion about the local s-axis is governed by part ID +RPIDS. If zero, no moment is computed about this axis. +RPIDT +*MAT_ELASTIC_6DOF_SPRING_DISCRETE_BEAM +DESCRIPTION +Rotational motion about the local t-axis is governed by part ID +RPIDT. If zero, no moment is computed about this axis. +*MAT_INELASTIC_SPRING_DISCRETE_BEAM +This is Material Type 94. This model permits elastoplastic springs with damping to be +represented with a discrete beam element type 6. A yield force versus deflection curve +is used which can vary in tension and compression. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +Variable +FLCID +HLCID +Type +F +F +3 +K +F +3 +C1 +F +4 +F0 +F +4 +C2 +F +5 +D +F +5 +6 +7 +8 +CDF +TDF +F +6 +F +7 +8 +DLE +GLCID +F +I + VARIABLE +DESCRIPTION +MID +RO +K +F0 +D +CDF +TDF +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density, see also volume in *SECTION_BEAM definition. +Elastic loading/unloading stiffness. This is required input. +Optional initial force. This option is inactive if this material is +referenced in a part referenced by material type *MAT_INELAS- +TIC_6DOF_SPRING +Optional viscous damping coefficient. +Compressive displacement at failure. Input as a positive number. +After failure, no forces are carried. This option does not apply to +zero length springs. +EQ.0.0: inactive. +Tensile displacement at failure. After failure, no forces are +carried. +EQ.0.0: inactive. +FLCID +*MAT_INELASTIC_SPRING_DISCRETE_BEAM +DESCRIPTION +Load curve ID, see *DEFINE_CURVE, defining the yield force +versus plastic deflection. If the origin of the curve is at (0,0) the +force magnitude is identical in tension and compression, i.e., only +the sign changes. If not, the yield stress in the compression is +used when the spring force is negative. The plastic displacement +increases monotonically in this implementation. The load curve +is required input. +HLCID +Load curve ID, see *DEFINE_CURVE, defining force versus +relative velocity (Optional). If the origin of the curve is at (0,0) the +force magnitude is identical for a given magnitude of the relative +velocity, i.e., only the sign changes. +C1 +C2 +Damping coefficient. +Damping coefficient +DLE +Factor to scale time units. +GLCID +Optional load curve ID, see *DEFINE_CURVE, defining a scale +factor versus deflection for load curve ID, HLCID. If zero, a scale +factor of unity is assumed. +Remarks: +The yield force is taken from the load curve: +𝐹𝑌 = 𝐹𝑦(Δ𝐿plastic) +where 𝐿plastic is the plastic deflection. A trial force is computed as: +and is checked against the yield force to determine 𝐹: +𝐹𝑇 = 𝐹𝑛 + K × Δ𝐿̇(Δ𝑡) +𝐹 = { +𝐹𝑌 𝑖𝑓 𝐹𝑇 > 𝐹𝑌 +𝐹𝑇 𝑖𝑓 𝐹𝑇 ≤ 𝐹𝑌 +The final force, which includes rate effects and damping, is given by: +𝐹𝑛+1 = 𝐹 × [1 + C1 × Δ𝐿̇ + C2 × sgn(Δ𝐿̇)ln (max {1. , +∣Δ𝐿̇∣ +DLE +})] + D×Δ𝐿̇ + 𝑔(Δ𝐿)ℎ(Δ𝐿̇) +Unless the origin of the curve starts at (0,0), the negative part of the curve is used when +the spring force is negative where the negative of the plastic displacement is used to +interpolate, 𝐹𝑦. The positive part of the curve is used whenever the force is positive. In +these equations, Δ𝐿 is the change in length +Δ𝐿 = current length - initial length +The cross sectional area is defined on the section card for the discrete beam elements, +See *SECTION_BEAM. The square root of this area is used as the contact thickness +offset if these elements are included in the contact treatment. +*MAT_INELASTIC_6DOF_SPRING_DISCRETE_BEAM +type, *MAT_INELASTIC_SPRING_DISCRETE_BEAM above +This is Material Type 95. This material model is defined for simulating the effects of +nonlinear inelastic and nonlinear viscous beams by using six springs each acting about +one of the six local degrees-of-freedom. The input consists of part ID's that reference +material +(type 94). +Generally, these referenced parts are used only for the definition of this material model +and are not referenced by any elements. The two nodes defining a beam may be +coincident to give a zero length beam, or offset to give a finite length beam. For finite +length discrete beams the absolute value of the variable SCOOR in the SECTION_- +BEAM input should be set to a value of 2.0, which causes the local r-axis to be aligned +along the two nodes of the beam to give physically correct behavior. The distance +between the nodes of a beam should not affect the behavior of this material model. A +triad must be used to orient the beam for zero length beams. + Card 1 +1 +Variable +MID +2 +RO +3 +4 +5 +6 +7 +8 +TPIDR +TPIDS +TPIDT +RPIDR +RPIDS +RPIDT +Type +A8 +F +I +I +I +I +I +I + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density, see also volume in *SECTION_BEAM definition. +TPIDR +TPIDS +TPIDT +RPIDR +RPIDS +Translational motion in the local r-direction is governed by part +ID TPIDR. If zero, no force is computed in this direction. +Translational motion in the local s-direction is governed by part +ID TPIDS. If zero, no force is computed in this direction. +Translational motion in the local t-direction is governed by part +ID TPIDT. If zero, no force is computed in this direction. +Rotational motion about the local r-axis is governed by part ID +RPIDR. If zero, no moment is computed about this axis. +Rotational motion about the local s-axis is governed by part ID +RPIDS. If zero, no moment is computed about this axis. +VARIABLE +RPIDT +DESCRIPTION +Rotational motion about the local t-axis is governed by part ID +RPIDT. If zero, no moment is computed about this axis. +This is Material Type 96. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +*MAT_BRITTLE_DAMAGE +3 +E +F +3 +4 +PR +F +4 +5 +6 +7 +8 +TLIMIT +SLIMIT +FTOUGH +SRETEN +F +5 +F +6 +F +7 +F +8 +Variable +VISC +FRA_RF +E_RF +YS_RF +EH_RF +FS_RF +SIGY +Type +F +F +F +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young's modulus. +Poisson's ratio. +TLIMIT +Tensile limit. +SLIMIT +Shear limit. +FTOUGH +Fracture toughness. +SRETEN +Shear retention. +VISC +Viscosity. +FRA_RF +Fraction of reinforcement in section. +E_RF +Young's modulus of reinforcement. +YS_RF +Yield stress of reinforcement. +EH_RF +Hardening modulus of reinforcement. +VARIABLE +DESCRIPTION +Failure strain (true) of reinforcement. +Compressive yield stress. +EQ.0: no compressive yield +FS_RF +SIGY +Remarks: +A full description of the tensile and shear damage parts of this material model is given +in Govindjee, Kay and Simo [1994,1995]. It is an anisotropic brittle damage model +designed primarily for concrete though it can be applied to a wide variety of brittle +materials. It admits progressive degradation of tensile and shear strengths across +smeared cracks that are initiated under tensile loadings. Compressive failure is +governed by a simplistic J2 flow correction that can be disabled if not desired. Damage +is handled by treating the rank 4 elastic stiffness tensor as an evolving internal variable +for the material. Softening induced mesh dependencies are handled by a characteristic +length method [Oliver 1989]. +Description of properties: +1. E is the Young's modulus of the undamaged material also known as the virgin +modulus. +2. υ is the Poisson's ratio of the undamaged material also known as the virgin +Poisson's ratio. +3. +𝑓𝑛 is the initial principal tensile strength (stress) of the material. Once this stress +has been reached at a point in the body a smeared crack is initiated there with a +normal that is co-linear with the 1st principal direction. Once initiated, the +crack is fixed at that location, though it will convect with the motion of the +body. As the loading progresses the allowed tensile traction normal to the +crack plane is progressively degraded to a small machine dependent constant. +The degradation is implemented by reducing the material's modulus normal to +the smeared crack plane according to a maximum dissipation law that incorpo- +rates exponential softening. The restriction on the normal tractions is given by +𝜙𝑡 = (𝐧 ⊗ 𝐧): σ − 𝑓𝑛 + (1 − 𝜀)𝑓𝑛(1 − exp[−𝐻𝛼]) ≤ 0 +where 𝐧 is the smeared crack normal, 𝜀 is the small constant, 𝐻 is the softening +modulus, and 𝛼 is an internal variable. 𝐻 is set automatically by the program; +see 𝑔𝑐 below. 𝛼 measures the crack field intensity and is output in the equiva- +lent plastic strain field, 𝜀̅𝑝, in a normalized fashion. +The evolution of alpha is governed by a maximum dissipation argument. +When the normalized value reaches unity it means that the material's strength +has been reduced to 2% of its original value in the normal and parallel direc- +tions to the smeared crack. Note that for plotting purposes it is never output +greater than 5. +4. +𝑓𝑠 is the initial shear traction that may be transmitted across a smeared crack +plane. The shear traction is limited to be less than or equal to 𝑓𝑠(1 − 𝛽)(1 − +exp[−𝐻𝛼]), through the use of two orthogonal shear damage surfaces. Note +that the shear degradation is coupled to the tensile degradation through the +internal variable alpha which measures the intensity of the crack field. 𝛽 is the +shear retention factor defined below. The shear degradation is taken care of by +reducing the material's shear stiffness parallel to the smeared crack plane. +5. +𝑔𝑐 is the fracture toughness of the material. It should be entered as fracture +energy per unit area crack advance. Once entered the softening modulus is +automatically calculated based on element and crack geometries. +6. 𝛽 is the shear retention factor. As the damage progresses the shear tractions +allowed across the smeared crack plane asymptote to the product 𝛽𝑓𝑠. +7. 𝜂 represents the viscosity of the material. Viscous behavior is implemented as a +simple Perzyna regularization method. This allows for the inclusion of first +order rate effects. The use of some viscosity is recommend as it serves as regu- +larizing parameter that increases the stability of calculations. +8. 𝜎𝑦 is a uniaxial compressive yield stress. A check on compressive stresses is +made using the J2 yield function 𝐬: 𝐬 − √2 +3 𝜎𝑦 ≤ 0, where 𝐬 is the stress deviator. +If violated, a J2 return mapping correction is executed. This check is executed +when (1) no damage has taken place at an integration point yet, (2) when dam- +age has taken place at a point but the crack is currently closed, and (3) during +active damage after the damage integration (i.e. as an operator split). Note that +if the crack is open the plasticity correction is done in the plane-stress subspace +of the crack plane. +A variety of experimental data has been replicated using this model from quasi-static to +explosive situations. Reasonable properties for a standard grade concrete would be +E = 3.15x106 psi, 𝑓𝑛 = 450 psi, 𝑓𝑠 = 2100 psi, 𝜈 = 0.2, 𝑔𝑐 = 0.8 lbs/in, 𝛽 = 0.03, 𝜂 = 0.0 psi- +sec, 𝜎𝑦 = 4200 psi. For stability, values of 𝜂 between 104 to 106 psi/sec are recommend- +ed. Our limited experience thus far has shown that many problems require nonzero +values of 𝜂 to run to avoid error terminations. +Various other internal variables such as crack orientations and degraded stiffness +tensors are internally calculated but currently not available for output. +*MAT_GENERAL_JOINT_DISCRETE_BEAM +This is Material Type 97. This model is used to define a general joint constraining any +combination of degrees of freedom between two nodes. The nodes may belong to rigid +or deformable bodies. In most applications the end nodes of the beam are coincident +and the local coordinate system (r,s,t axes) is defined by CID . + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +TR +I +4 +TS +I +5 +TT +I +6 +RR +I +7 +RS +I +8 +RT +Remarks +1 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RPST +RPSR +Type +Remarks +F +2 +F + VARIABLE +DESCRIPTION +MID +RO +TR +TS +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density, see also volume in *SECTION_BEAM definition. +Translational constraint code along the r-axis (0 ⇒ free, 1 ⇒ +constrained) +Translational constraint code along the s-axis (0 ⇒ free, 1 ⇒ +constrained) +*MAT_GENERAL_JOINT_DISCRETE_BEAM +DESCRIPTION +TT +RR +RS +RT +RPST +RPSR +Remarks: +Translational constraint code along the t-axis (0 ⇒ free, 1 ⇒ +constrained) +Rotational constraint code about the r-axis (0 ⇒ free, 1 ⇒ +constrained) +Rotational constraint code about the s-axis (0 ⇒ free, 1 ⇒ +constrained) +Rotational constraint code about the t-axis (0 ⇒ free, 1 ⇒ +constrained) +Penalty stiffness scale factor for translational constraints. +Penalty stiffness scale factor for rotational constraints. +1. For explicit calculations, the additional stiffness due to this joint may require +addition mass and inertia for stability. Mass and rotary inertia for this beam +element is based on the defined mass density, the volume, and the mass mo- +ment of inertia defined in the *SECTION_BEAM input. +2. The penalty stiffness applies to explicit calculations. For implicit calculations, +constraint equations are generated and imposed on the system equations; there- +fore, these constants, RPST and RPSR, are not used. +*MAT_SIMPLIFIED_JOHNSON_COOK_{OPTION} +Available options include: + +STOCHASTIC +This is Material Type 98 implementing Johnson/Cook strain sensitive plasticity. It is +used for problems where the strain rates vary over a large range. In contrast to the full +Johnson/Cook model (material type 15) this model +introduces the following +simplifications: +1. +2. +thermal effects and damage are ignored, +and the maximum stress is directly limited since thermal softening which is +very significant in reducing the yield stress under adiabatic loading is not +available. +An iterative plane stress update is used for the shell elements, but due to the +simplifications related to thermal softening and damage, this model is 50% faster than +the full Johnson/Cook implementation. To compensate for the lack of thermal +softening, limiting stress values are introduced to keep the stresses within reasonable +limits. +A resultant formulation for the Belytschko-Tsay, the C0 Triangle, and the fully +integrated type 16 shell elements is available and can be activated by specifying either +zero or one through thickness integration point on the *SECTION_SHELL card. While +less accurate than through thickness integration, this formulation runs somewhat faster. +Since the stresses are not computed in the resultant formulation, the stresses written to +the databases for the resultant elements are set to zero. +This model is also available for the Hughes-Liu beam, the Belytschko-Schwer beam, and +for the truss element. For the resultant beam formulation, the rate effects are +approximated by the axial rate, since the thickness of the beam about it bending axes is +unknown. Because this model is primarily used for structural analysis, the pressure is +determined using the linear bulk modulus. +Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +VP +F +Default +none +none +none +none +0.0 +6 +7 +8 + Card 2 +Variable +Type +1 +A +F +2 +B +F +3 +N +F +4 +C +F +5 +6 +7 +8 +PSFAIL +SIGMAX +SIGSAT +EPSO +F +F +F +F +Default +none +0.0 +0.0 +0.0 +1.0E+17 SIGSAT 1.0E+28 +1.0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +VP +A +B +N +C +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus +Poisson’s ratio +Formulation for rate effects: +EQ.0.0: Scale yield stress (default), +EQ.1.0: Viscoplastic formulation. +This option applies only to the 4-node shell and 8-node thick shell +if and only if through thickness integration is used. +See equations below. +See equations below. +See equations below. +See equations below. +VARIABLE +DESCRIPTION +PSFAIL +Effective plastic strain at failure. If zero failure is not considered. +Maximum stress obtainable from work hardening before rate +effects are added (optional). This option is ignored if VP = 1.0 +Saturation stress which limits the maximum value of effective +stress which can develop after rate effects are added (optional). +Quasi-static threshold strain rate. See description under *MAT_- +015. +SIGMAX +SIGSAT +EPS0 +Remarks: +Johnson and Cook express the flow stress as +𝜎𝑦 = (𝐴 + 𝐵𝜀̅ 𝑝𝑛 +)(1 + 𝐶 ln 𝜀∗̇ ) +where +𝐴, 𝐵, 𝐶 = input constants +𝜀̅𝑝 = effective plastic strain +𝜀∗̇ = +𝜀̅ +EPS0 += normalized effective strain rate +The maximum stress is limited by SIGMAX and SIGSAT by: +𝜎𝑦 = min{min[𝐴 + 𝐵𝜀̅ 𝑝𝑛 +, SIGMAX](1 + 𝑐 ln 𝜀∗̇ ), SIGSAT} +Failure occurs when the effective plastic strain exceeds PSFAIL. +If the viscoplastic option is active, VP = 1.0, the parameters SIGMAX and SIGSAT are +ignored since these parameters make convergence of the viscoplastic strain iteration +loop difficult to achieve. The viscoplastic option replaces the plastic strain in the +forgoing equations by the viscoplastic strain and the strain rate by the viscoplastic strain +rate. Numerical noise is substantially reduced by the viscoplastic formulation. +The STOCHASTIC option allows spatially varying yield and failure behavior. See *DE- +FINE_STOCHASTIC_VARIATION for additional information. +LS-DYNA R10.0 +*MAT_SIMPLIFIED_JOHNSON_COOK_ORTHOTROPIC_DAMAGE +This is Material Type 99. This model, which is implemented with multiple through +thickness integration points, is an extension of model 98 to include orthotropic damage +as a means of treating failure in aluminum panels. Directional damage begins after a +defined failure strain is reached in tension and continues to evolve until a tensile +rupture strain is reached in either one of the two orthogonal directions. After rupture is +detected at NUMINT integration points, the element is deleted. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +VP +F +6 +7 +8 +EPPFR +LCDM +NUMINT +F +I +I +Default +none +none +none +none +0.0 +1.e+16 optional +all +points + Card 2 +Variable +Type +1 +A +F +2 +B +F +3 +N +F +4 +C +F +5 +6 +7 +8 +PSFAIL +SIGMAX +SIGSAT +EPSO +F +F +F +F +Default +none +0.0 +0.0 +0.0 +1.0E+17 SIGSAT 1.0E+28 +1.0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus +Poisson’s ratio +*MAT_SIMPLIFIED_JOHNSON_COOK_ORTHOTROPIC_DAMAGE *MAT_099 + VARIABLE +DESCRIPTION +VP +Formulation for rate effects: +EQ.0.0: Scale yield stress (default), +EQ.1.0: Viscoplastic formulation. +EPPFR +LCDM +NUMINT +This option applies only to the 4-node shell and 8-node thick shell +if and only if through thickness integration is used. +Plastic strain at which material ruptures (logarithmic). +Load curve ID defining nonlinear damage curve. See Figure +M81-2. +Number of through thickness integration points which must fail +before the element is deleted. (If zero, all points must fail.) The +default of all integration points is not recommended since +elements undergoing large strain are often not deleted due to +nodal fiber rotations which limit 0strains at active integration +points after most points have failed. Better results are obtained if +NUMINT is set to 1 or a number less than one half of the number +of through thickness points. For example, if four through +thickness points are used, NUMINT should not exceed 2, even for +fully integrated shells which have 16 integration points. +A +B +N +C +See equations below. +See equations below. +See equations below. +See equations below. +PSFAIL +Principal plastic strain at failure. If zero failure is not considered. +SIGMAX +SIGSAT +EPS0 +Maximum stress obtainable from work hardening before rate +effects are added (optional). This option is ignored if VP = 1.0 +Saturation stress which limits the maximum value of effective +stress which can develop after rate effects are added (optional). +Quasi-static threshold strain rate. See description under *MAT_- +015. +*MAT_SIMPLIFIED_JOHNSON_COOK_ORTHOTROPIC_DAMAGE +See the description for the SIMPLIFIED_JOHNSON_COOK model above. +*MAT_100 +This is Material Type 100. The material model applies to beam element type 9 and to +solid element type 1. The failure models apply to both beam and solid elements. +In the case of solid elements, if hourglass type 4 is specified then hourglass type 4 will +be used, otherwise, hourglass type 6 will be automatically assigned. Hourglass type 6 is +preferred. +The beam elements, based on the Hughes-Liu beam formulation, may be placed +between any two deformable shell surfaces and tied with constraint contact, *CON- +TACT_SPOTWELD, which eliminates the need to have adjacent nodes at spot weld +locations. Beam spot welds may be placed between rigid bodies and rigid/deformable +bodies by making the node on one end of the spot weld a rigid body node which can be +an extra node for the rigid body, see *CONSTRAINED_EXTRA_NODES_OPTION. In +the same way rigid bodies may also be tied together with this spot weld option. This +weld option should not be used with rigid body switching. The foregoing advice is +valid if solid element spot welds are used; however, since the solid elements have just +three degrees-of-freedom at each node, *CONTACT_TIED_SURFACE_TO_SURFACE +must be used instead of *CONTACT_SPOTWELD. +In flat topologies the shell elements have an unconstrained drilling degree-of-freedom +which prevents torsional forces from being transmitted. If the torsional forces are +deemed to be important, brick elements should be used to model the spot welds. +Beam and solid element force resultants for MAT_SPOTWELD are written to the spot +weld force file, swforc, and the file for element stresses and resultants for designated +elements, elout. +It is advisable to include all spot welds, which provide the slave nodes, and spot +welded materials, which define the master segments, within a single *CONTACT_- +SPOTWELD interface for beam element spot welds or a *CONTACT_TIED_SUR- +FACE_TO_SURFACE interface for solid element spot welds. As a constraint method +these interfaces are treated independently which can lead to significant problems if such +interfaces share common nodal points. An added benefit is that memory usage can be +substantially less with a single interface. +Available options include: + +DAMAGE-FAILURE +The DAMAGE-FAILURE option causes one additional line to be read with the damage +parameter and a flag that determines how failure is computed from the resultants. On +this line the parameter, RS, if nonzero, invokes damage mechanics combined with the +plasticity model to achieve a smooth drop off of the resultant forces prior to the removal +of the spot weld. The parameter OPT determines the method used in computing +resultant based failure, which is unrelated to damage. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +SIGY +F +6 +EH +F +7 +DT +F +Card 2 for no failure. Additional card for keyword option. + Card 2 +1 +2 +3 +4 +5 +6 +7 +Variable +EFAIL +NRR +NRS +NRT +MRR +MSS +MTT +Type +F +F +F +F +F +F +F +8 +TFAIL +F +8 +NF +F +Card 2 for resultant based failure. Additional card for DAMAGE-FAILURE keyword +option with OPT = -1.0 or 0.0. + Card 2 +1 +2 +3 +4 +5 +6 +7 +Variable +EFAIL +NRR +NRS +NRT +MRR +MSS +MTT +Type +F +F +F +F +F +F +F +8 +NF +F +Card 2 for stress based failure. Additional card for DAMAGE-FAILURE keyword +option with OPT = 1.0 and positive values in fields 2 and 3. + Card 2 +1 +2 +3 +4 +5 +6 +7 +Variable +EFAIL +SIGAX +SIGTAU +Type +F +F +F +8 +NF +Card 2 for stress based failure. Additional card for DAMAGE-FAILURE keyword +option with OPT = 1.0 and negative values in fields 2 and 3. + Card 2 +1 +2 +3 +4 +5 +6 +7 +Variable +EFAIL +-LCAX +-LCTAU +Type +F +F +F +8 +NF +F +Card 2 for user subroutine based failure. Additional card for DAMAGE-FAILURE +keyword option with OPT = 2.0, 12, or 22. + Card 2 +1 +2 +3 +4 +5 +6 +7 +Variable +EFAIL +USRV1 +USRV2 +USRV3 +USRV4 +USRV5 +USRV6 +Type +F +F +F +F +F +F +F +Card 2 for OPT = 3.0 or 4.0. + Card 2 +1 +Variable +EFAIL +Type +F +Card 2 for OPT = 5.0. + Card 2 +1 +Variable +EFAIL +Type +F +2 +ZD +F +2 +ZD +F +3 +ZT +F +3 +ZT +F +4 +5 +6 +7 +ZALP1 +ZALP2 +ZALP3 +ZRRAD +F +F +F +F +5 +6 +7 +8 +4 +ZT2 +F +8 +NF +F +8 +NF +Card 2 for OPT = 6.0, 7.0, 9.0, or 10.0. + Card 2 +1 +2 +3 +4 +5 +6 +7 +Variable +EFAIL +Type +F +Card 2 for OPT = 11.0. + Card 2 +1 +2 +3 +4 +5 +6 +7 +Variable +EFAIL +LCT +LCC +Type +F +F +F +8 +NF +F +8 +NF +F +Additional card for the DAMAGE-FAILURE option. + Card 3 +Variable +1 +RS +2 +3 +4 +5 +6 +7 +8 +OPT +FVAL +TRUE_T +ASFF +BETA +DMGOPT +Type +F +F +F +F +I +F +F +Optional 2nd additional card for the DAMAGE-FAILURE option, read only if +DMGOPT = -1 on card 3. + Card 3A +1 +2 +3 +4 +5 +6 +7 +8 +Variable DMGOPT +FMODE +FFCAP +Type +F +F +F +Additional card for OPT = 12 or 22. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +USRV7 +USRV8 +USRV9 +USRV10 +USRV11 +USRV12 +USRV13 +USRV14 +Type +F +F +F +F +F +F +F +Additional card for OPT = 12 or 22 + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +USRV15 +USRV16 +USRV17 +USRV18 +USRV19 +USRV20 +USRV21 +USRV22 +Type +F +F +F +F +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +SIGY +EH +DT +TFAIL +EFAIL +NRR +NRS +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus. If input as negative, a uniaxial option for solid +spot welds is invoked; see “Uniaxial option” in remarks. +Poisson’s ratio +GT.0: Initial yield stress. +LT.0: A yield curve or table is assigned by |SIGY|. +Plastic hardening modulus, 𝐸ℎ +Time step size for mass scaling, Δ𝑡 +Failure time if nonzero. If zero this option is ignored. +Effective plastic strain in weld material at failure. If the damage +option is inactive, the spot weld element is deleted when the +plastic strain at each integration point exceeds EFAIL. If the +damage option is active, the plastic strain must exceed the rupture +strain (RS) at each integration point before deletion occurs. +𝐹 at failure +Axial force resultant 𝑁𝑟𝑟𝐹 or maximum axial stress 𝜎𝑟𝑟 +depending on the value of OPT . If zero, failure due to +this component is not considered. If negative, |NRR| is the load +curve ID defining the maximum axial stress at failure as a function +of the effective strain rate. +Force resultant 𝑁𝑟𝑠𝐹 or maximum shear stress 𝜏𝐹 at failure +depending on the value of OPT . If zero, failure due to +this component is not considered. If negative, |NRS| is the load +VARIABLE +DESCRIPTION +NRT +MRR +MSS +MTT +curve ID defining the maximum shear stress at failure as a +function of the effective strain rate. +Force resultant 𝑁𝑟𝑡𝐹 at failure. If zero, failure due to this +component is not considered. +Torsional moment resultant 𝑀𝑟𝑟𝐹 at failure. If zero, failure due to +this component is not considered. +Moment resultant 𝑀𝑠𝑠𝐹 at failure. If zero, failure due to this +component is not considered. +Moment resultant 𝑀𝑡𝑡𝐹 at failure. If zero, failure due to this +component is not considered. +NF +Number of force vectors stored for filtering. +SIGAX +SIGTAU +LCAX +LCTAU +Maximum axial stress 𝜎𝑟𝑟 +component is not considered. +𝐹 at failure. If zero, failure due to this +Maximum shear stress 𝜏𝐹 at failure. If zero, failure due to this +component is not considered. +Load curve ID defining the maximum axial stress at failure as a +function of the effective strain rate. Input as a negative number. +Load curve ID defining the maximum shear stress at failure as a +function of the effective strain rate. Input as a negative number. +USRVn +Failure constants for user failure subroutine, 𝑛 = 1,2, … ,6 +ZD +ZT +Notch diameter +Sheet thickness. +ZALP1 +Correction factor alpha1 +ZALP2 +Correction factor alpha2 +ZALP3 +Correction factor alpha3 +ZRRAD +Notch root radius (OPT = 3.0 only). +ZT2 +LCT +2-514 (EOS) +Second sheet thickness (OPT = 5.0 only) +VARIABLE +DESCRIPTION +LCC +RS +OPT +under tension as a function of loading direction (in degree range 0 +to 90). Table defines these curves as functions of strain rates. See +remarks. (OPT = 11.0 only) +Load curve or Table ID. Load curve defines resultant failure force +under compression as a function of loading direction (in degree +range 0 to 90). Table defines these curves as functions of strain +rates. See remarks. (OPT = 11.0 only) +Rupture strain. Define if and only if damage is active. +Failure option: +EQ.-9: OPT = 9 failure is evaluated and written to the swforc +file, but element failure is suppressed. +EQ.-2: same as option –1 but in addition, the peak value of the +failure criteria and the time it occurs is stored and is +written into the swforc database. This information may +be necessary since the instantaneous values written at +specified time intervals may miss the peaks. Additional +storage is allocated to store this information. +EQ.-1: OPT = 0 failure is evaluated and written into the swforc +file, but element failure is suppressed +EQ.0: resultant based failure +EQ.1: stress based failure computed from resultants (Toyota) +EQ.2: user subroutine uweldfail to determine failure +EQ.3: notch stress based failure. (beam and hex assembly +welds only). +EQ.4: stress intensity factor at failure. (beam and hex assembly +welds only). +EQ.5: structural stress at failure (beam and hex assembly welds +only). +EQ.6: stress based failure computed from resultants (Toyota). +In this option a shell strain rate dependent failure model +is used (beam and hex assembly welds only). The static +failure stresses are defined by part ID using the keyword +*DEFINE_SPOTWELD_RUPTURE_STRESS. +EQ.7: stress based failure for solid elements (Toyota) with peak +stresses computed from resultants, and strength values +input for pairs of parts, see *DEFINE_SPOTWELD_- +VARIABLE +DESCRIPTION +FAILURE_RESULTANTS. Strain rate effects are option- +al. +EQ.8: not used. +EQ.9: stress based failure from resultants (Toyota). In this +option a shell strain rate dependent failure model is used +(beam welds only). The static failure stresses are defined +by part ID using the keyword *DEFINE_SPOTWELD_- +RUPTURE_PARAMETER. +EQ.10: stress based failure with rate effects. Failure data is +defined by material using the keyword *DEFINE_- +SPOWELD_FAILURE. +EQ.11: resultant based failure (beams only). In this option load +curves or tables LCT (tension) and LCC (compression) +can be defined as resultant failure force vs. loading di- +rection (curve) or resultant failure force vs. loading di- +rection vs. strain rate (table). +EQ.12: user subroutine uweldfail12 with 22 material constants +to determine damage and failure. +EQ.22: user subroutine uweldfail22 with 22 material constants +to determine failure. +FVAL +Failure parameter. If OPT: +EQ.-2: Not used. +EQ.-1: Not used. +EQ.0: Function +ID +(*DEFINE_FUNCTION) +define +alternative Weld Failure. If this is set, the values given +for NRR, NRS, NRT, MRR, MSS and MTT in Card 2 are +ignored. +to +EQ.1: Not used. +EQ.2: Not used. +EQ.3: Notch stress value at failure (KF). +EQ.4: Stress intensity factor value at failure (KeqF). +EQ.5: Structural stress value at failure (sF). +EQ.6: Number of cycles that failure condition must be met to +trigger beam deletion. +EQ.7: Not used. +n5 +n8 +n4 +n6 +n7 +n3 +n1 +n2 +Figure M100-1. A solid element used as spot weld is shown. When resultant +based failure is used orientation is very important. Nodes n1-n4 attach to the +lower shell mid-surface and nodes n5-n8 attach to the upper shell mid-surface. +The resultant forces and moments are computed based on the assumption that +the brick element is properly oriented. + VARIABLE +DESCRIPTION +TRUE_T +EQ.9: Number of cycles that failure condition must be met to +trigger beam deletion. +EQ.10: ID of data defined by *DEFINE_SPOTWELD_FAILURE. +True weld thickness. This optional value is available for solid +element failure, and is used to reduce the moment contribution to +the failure calculation from artificially thick weld elements under +shear loading so shear failure can be modeled more accurately. +See comments under the remarks for *MAT_SPOTWELD_DAIM- +LER CHRYSLER +ASFF +Weld assembly simultaneous failure flag +EQ.0: Damaged elements fail individually. +EQ.1: Damaged elements +fail when +first reaches +failure +criterion. +BETA +Damage model decay rate. +DMGOPT +Damage option flag. If DMGOPT: +EQ.0: Plastic strain based damage. +EQ.1: Plastic strain based damage with post damage stress +limit +VARIABLE +DESCRIPTION +EQ.2: Time based damage with post damage stress limit +EQ.10: Like DMGOPT = 0, but failure option will initiate +damage +EQ.11: Like DMGOPT = 1, but failure option will initiate +damage +EQ.12: Like DMGOPT = 2, but failure option will initiate +damage +FMODE +Failure surface ratio for damage or failure, for DMGOPT = 10, 11, +or 12 +EQ.0: Damage initiates +GT.0: Damage or failure +FFCAP +Failure function limit for OPT = 0 or -1, and DMGOPT = 10, 11, or +12 +EQ.0: Damage initiates +GT.0: Damage or failure +USRVn +Failure constants for OPT = 12 or 22 user defined failure, +𝑛 = 7, 8, … , 22 +Weld Failure +Spot weld material is modeled with isotropic hardening plasticity coupled to failure +models. EFAIL specifies a failure strain which fails each integration point in the spot +weld independently. The OPT parameter is used to specify a failure criterion that fails +the entire weld element when the criterion is met. Alternatively, EFAIL and OPT +option may be used to initiate damage when the DAMAGE-FAILURE option is active +using RS, BETA, and DMGOPT as described below. +Beam spot weld elements can use any OPT value except 7. Brick spot weld elements +can use any OPT value except 3, 4, 5, 6, 9, and -9. Hex assembly spot welds can use any +OPT value except 9 and -9. +OPT = -1 or 0 +OPT = 0 and OPT = -1 invoke a resultant-based failure criterion that fails the weld if the +resultants are outside of the failure surface defined by: +[ +max(𝑁𝑟𝑟, 0) +𝑁𝑟𝑟𝐹 +] +] ++ [ +𝑁𝑟𝑠 +𝑁𝑟𝑠𝐹 ++ [ +𝑁𝑟𝑡 +𝑁𝑟𝑡𝐹 +] +] ++ [ +𝑀𝑟𝑟 +𝑀𝑟𝑟𝐹 ++ [ +𝑀𝑠𝑠 +𝑀𝑠𝑠𝐹 +] +] ++ [ +𝑀𝑡𝑡 +𝑀𝑡𝑡𝐹 +− 1 = 0 +where the numerators in the equation are the resultants calculated in the local +coordinates of the cross section, and the denominators are the values specified in the +input. If OPT = -1, the failure surface equation is evaluated, but element failure is +suppressed. This allows easy identification of vulnerable spot welds when post- +processing. Failure is likely to occur if FC > 1.0. +Alternatively a *DEFINE_FUNCTION could be used to define the Weld Failure for +OPT = 0. Then set FVAL = function ID. Such a function could look like this: +*DEFINE_FUNCTION + 100 + func(nrr,nrs,nrt,mrr,mss,mtt)= (nrr/5.0)*(nrr/5.0) +The six arguments for this function (nrr, …, mtt) are the force +and moment resultants during the computation. +OPT = 1: +OPT = 1 invokes a stress based failure model, which was developed by Toyota Motor +Corporation and is based on the peak axial and transverse shear stresses. The weld fails +if the stresses are outside of the failure surface defined by +( +𝜎𝑟𝑟 +𝐹 ) +𝜎𝑟𝑟 ++ ( +𝜏𝐹) +− 1 = 0 +If strain rates are considered then the failure criteria becomes: +[ +𝜎𝑟𝑟 +] +𝐹 (𝜀̇eff) +𝜎𝑟𝑟 ++ [ +] +𝜏𝐹(𝜀̇eff) +− 1 = 0 +where 𝜎𝑟𝑟 +stresses are calculated from the resultants using simple beam theory. +𝐹 (𝜀̇eff) and 𝜏𝐹(𝜀̇eff) are defined by load curves LCAX and LCTAU. The peak +𝜎𝑟𝑟 = +𝑁𝑟𝑟 ++ +2 + 𝑀𝑡𝑡 +√𝑀𝑠𝑠 +2 + 𝑁𝑟𝑡 +√𝑁𝑟𝑠 +where the area and section modulus are given by: +𝑀𝑟𝑟 +2𝑍 +𝜏 = ++ +𝐴 = 𝜋 +𝑍 = 𝜋 +𝑑2 +𝑑3 +32 +and d is the equivalent diameter of the beam element or solid element used as a spot +weld. +*MAT_SPOTWELD +OPT = 2 invokes a user-written subroutine uweldfail, documented in Appendix Q. +OPT = 12 or 22 +OPT = 12 and OPT = 22 invoke similar user-written subroutines, uweldfail12, or, +uweldfail22 respectively. Both allow up to 22 failure parameters to be used rather than +the 6 allowed with OPT = 2. OPT = 12 also allows user control of weld damage. +OPT = 3 +OPT = 3 invokes a failure based on notch stress, see Zhang [1999]. Failure occurs when +the failure criterion: +is satisfied. The notch stress is given by the equation: +𝜎𝑘 − 𝜎𝑘𝐹 ≥ 0 +𝜎𝑘 = 𝛼1 +⎜⎛1 + +4𝐹 +𝜋𝑑𝑡 ⎝ +√3 + √19 +8√𝜋 +√ +⎟⎞ + 𝛼2 +𝜌⎠ +6𝑀 +𝜋𝑑𝑡2 +⎜⎛1 + +⎝ +√3𝜋 +√ +⎟⎞ + 𝛼3 +𝜌⎠ +4𝐹𝑟𝑟 +𝜋𝑑2 +⎜⎛1 + +⎝ +3√2𝜋 +√ +⎟⎞ +𝜌⎠ +Here, +𝐹 = √𝐹𝑟𝑠 +2 +2 + 𝐹𝑟𝑡 +𝑀 = √𝑀𝑠𝑠 +2 +2 + 𝑀𝑡𝑡 +and 𝛼𝑖 𝑖 = 1,2,3 are input corrections factors with default values of unity. If spot welds +are between sheets of unequal thickness, the minimum thickness of the spot welded +sheets may be introduced as a crude approximation. +OPT = 4 +OPT = 4 invokes failure based on structural stress intensity, see Zhang [1999]. Failure +occurs when the failure criterion: +is satisfied where +and +𝐾eq − 𝐾eqF ≥ 0 +𝐾eq = √𝐾𝐼 +2 +2 + 𝐾𝐼𝐼 +𝐾𝐼 = 𝛼1 +√3𝐹 +2𝜋𝑑√𝑡 ++ 𝛼2 +2√3𝑀 +𝜋𝑑𝑡√𝑡 ++ 𝛼3 +5√2𝐹𝑟𝑟 +3𝜋𝑑√𝑡 +𝐾𝐼𝐼 = 𝛼1 +2𝐹 +𝜋𝑑√𝑡 +Here, F and M are as defined above for the notch stress formulas and again, 𝛼𝑖 𝑖 = +1,2,3 are input corrections factors with default values of unity. If spot welds are +between sheets of unequal thickness, the minimum thickness of the spot welded sheets +may be used as a crude approximation. +The maximum structural stress at the spot weld was utilized successfully for predicting +the fatigue failure of spot welds, see Rupp, et. al. [1994] and Sheppard [1993]. The +corresponding results according to Rupp, et. al. are listed below where it is assumed +that they may be suitable for crash conditions. +OPT = 5 +OPT = 5 invokes failure by +max(𝜎𝑣1, 𝜎𝑣2, 𝜎𝑣3) − 𝜎𝑠𝐹 = 0 +where 𝜎𝑠𝐹 is the critical value of structural stress at failure. It is noted that the forces +and moments in the equations below are referred to the beam nodes 1, 2, and to the +midpoint, respectively. The three stress values, 𝜎𝑣1, 𝜎𝑣2, 𝜎𝑣3, are defined by: +𝜎𝑣1(𝜁 ) = +𝐹𝑟𝑠1 +𝜋𝑑𝑡1 +cos𝜁 + +𝐹𝑟𝑡1 +𝜋𝑑𝑡1 +sin𝜁 − +1.046𝛽1𝐹𝑟𝑟1 +𝑡1√𝑡1 +− +1.123𝑀𝑠𝑠1 +𝑑𝑡1√𝑡1 +sin𝜁 + +1.123𝑀𝑡𝑡1 +𝑑𝑡1√𝑡1 +cos𝜁 +with +𝛽1 = { +0 𝐹𝑟𝑟1 ≤ 0 +1 𝐹𝑟𝑟1 > 0 +𝜎𝑣2(𝜁 ) = +𝐹𝑟𝑠2 +𝜋𝑑𝑡2 +cos𝜁 + +𝐹𝑟𝑡2 +𝜋𝑑𝑡2 +sin𝜁 − +1.046𝛽1𝐹𝑟𝑟2 +𝑡2√𝑡2 ++ +1.123𝑀𝑠𝑠2 +𝑑𝑡2√𝑡2 +sin𝜁 − +1.123𝑀𝑡𝑡2 +𝑑𝑡2√𝑡2 +cos𝜁 +with +where +𝛽2 = { +0 𝐹𝑟𝑟2 ≤ 0 +1 𝐹𝑟𝑟2 > 0 +𝜎𝑣3(𝜁 ) = 0.5𝜎(𝜁 ) + 0.5𝜎(𝜁 )cos(2𝛼) + 0.5𝜏(𝜁 )sin(2𝛼) +𝜎(𝜁 ) = +𝜏(𝜁 ) = +𝛼 = +32𝑀𝑡𝑡 +𝜋𝑑3 cos𝜁 +32𝑀𝑠𝑠 +𝜋𝑑3 sin𝜁 − +16𝐹𝑟𝑡 +3𝜋𝑑2 cos2𝜁 +4𝛽3𝐹𝑟𝑟 +𝜋𝑑2 + +16𝐹𝑟𝑠 +3𝜋𝑑2 sin2𝜁 + +tan−1 2𝜏(𝜁 ) +𝜎(𝜁 ) +𝛽3 = { +0 𝐹𝑟𝑟 ≤ 0 +1 𝐹𝑟𝑟 > 0 +The stresses are calculated for all directions, 0° ≤ 𝜁 ≤ 90°, in order to find the +maximum. +OPT = 10 +OPT = 10 invokes the failure criterion developed by Lee and Balur (2011). It is available +for welds modeled by beam elements, solid elements, or solid assemblies. A detailed +discussion of the criterion is given in the user’s manual section for *DEFINE_- +SPOTWELD_FAILURE. +OPT = 11 +OPT = 11 invokes a resultant force based failure criterion for beams. With correspond- +ing load curves or tables LCT and LCC, resultant force at failure 𝐹𝑓𝑎𝑖𝑙 can be defined as +function of loading direction 𝛾 (curve ) or loading direction 𝛾 and effective strain rate 𝜀̇ +(table): +with the following definitions for loading direction (in degree) and effective strain rate: +𝐹fail = 𝑓 (𝛾) or 𝐹fail = 𝑓 (𝛾, 𝜀̇) +𝛾 = tan−1 (∣ +𝐹shear +𝐹axial +∣) , 𝜀̇ = [ +(𝜀̇axial +2 + 𝜀shear +2 ̇ )] +1/2 +It depends on the sign of the axial beam force, if LCT or LCC are used for failure +condition: +𝐹axial > 0: [𝐹axial +2 + 𝐹shear +𝐹axial < 0: [𝐹axial +2 + 𝐹shear +1/2 +] +1/2 +] +> Ffail,LCT → failure +> Ffail,LCC → failure +For all OPT failure criteria, if a zero is input for a failure parameter on card 2, the +corresponding term will be omitted from the equation. For example, if for OPT = 0, +only 𝑁𝑟𝑟𝐹 is nonzero, the failure surface is reduced to |𝑁𝑟𝑟| = 𝑁𝑟𝑟𝐹. +Similarly, if the failure strain EFAIL is set to zero, the failure strain model is not used. +Both EFAIL and OPT failure may be active at the same time. +NF specifies the number of terms used to filter the stresses or resultants used in the OPT +failure criterion. NF cannot exceed 30. The default value is set to zero which is +generally recommended unless oscillatory resultant forces are observed in the time +history databases. Although welds should not oscillate significantly, this option was +added for consistency with the other spot weld options. NF affects the storage since it +is necessary to store the resultant forces as history variables. The NF parameter is +available only for beam element welds. +The inertias of the spot welds are scaled during the first time step so that their stable +time step size is Δ𝑡. A strong compressive load on the spot weld at a later time may +reduce the length of the spot weld so that stable time step size drops below Δ𝑡. If the +value of Δ𝑡 is zero, mass scaling is not performed, and the spot welds will probably +limit the time step size. Under most circumstances, the inertias of the spot welds are +small enough that scaling them will have a negligible effect on the structural response +and the use of this option is encouraged. +Spot weld force history data is written into the swforc ASCII file. In this database the +resultant moments are not available, but they are in the binary time history database +and in the ASCII elout file. +Damage +When the DAMAGE-FAILURE option is invoked, the constitutive properties for the +damaged material are obtained from the undamaged material properties. The amount +of damage evolved is represented by the constant, 𝜔, which varies from zero if no +damage has occurred to unity for complete rupture. For uniaxial loading, the nominal +stress in the damaged material is given by +𝜎nominal = +where P is the applied load and A is the surface area. The true stress is given by: +where 𝐴loss is the void area. The damage variable can then be defined: +𝜎true = +𝐴 − 𝐴loss +where, +𝜔 = +𝐴loss +0 ≤ 𝜔 ≤ 1 +In this model, damage is initiated when the effective plastic strain in the weld exceeds +the failure strain, EFAIL. If DMGOPT = 10, 11, or 12, damage will initiate when the +effective plastic strain exceeds EFAIL, or when the failure criterion is met, which ever +occurs first. The failure criterion is specified by OPT parameter. After damage initiates, +the damage variable is evaluated by one of two ways. +For DMGOPT = 0, 1, 10, or 11, the damage variable is a function of effective plastic +strain in the weld: +𝜀failure +≤ 𝜀eff +𝑝 ≤ 𝜀rupture +⇒ 𝜔 = +𝑝 − 𝜀failure +𝜀eff +− 𝜀failure +𝜀rupture +where 𝜀failure +a function of time: + = EFAIL and 𝜀rupture + = RS. For DMGOPT = 2 or 12, the damage variable is +𝑡failure ≤ 𝑡 ≤ 𝑡rupture ⇒ 𝜔 = +𝑡 − 𝑡failure +𝑡rupture +where 𝑡failure is the time at which damage initiates, and 𝑡rupture = RS. For this criteria, +𝑝 exceeds EFAIL, or the time when the failure +𝑡failure is set to either the time when 𝜀eff +criterion is met. +For DMGOPT = 1, the damage behavior is the same as for DMGOPT = 0, but an +additional damage variable is calculated to prevent stress growth during softening. +Similarly, DMGOPT = 11 behaves like DMGOPT = 10 except for the additional damage +variable. This additional function is also used with DMGOPT = 2 and 12. The effect of +this additional damage function is noticed only in brick and brick assembly welds in +tension loading where it prevents growth of the tensile force in the weld after damage +initiates. +For DMGOPT = 10, 11, or 12 an optional FMODE parameter determines whether a weld +that reaches the failure surface will fail immediately, or initiate damage. The failure +surface calculation has shear terms, which may include the torsional moment, and also +normal and bending terms. If FMODE is input with a value between 0 and 1, then +when the failure surface is reached, the sum of the square of the shear terms is divided +by the sum of the square of all terms. If this ratio exceeds FMODE, then the weld will +fail immediately. If the ratio is less than or equal to FMODE, then damage will initiate. +The FMODE option is available only for brick and brick assembly welds. +For resultant based failure (OPT = -1 or 0) and DMGOPT = 10, 11, or 12 an optional +FFCAP parameter determines whether a weld that reaches the failure surface will fail +immediately. After damage initiation, the failure function can reach values above 1.0. +This can now be limited by the FFCAP value (should be larger than 1.0): +max(𝑁𝑟𝑟, 0) +] +𝑁𝑟𝑟𝐹 +⎜⎛[ +⎝ ++ [ +𝑁𝑟𝑠 +𝑁𝑟𝑠𝐹 +] +] ++ [ +𝑁𝑟𝑡 +𝑁𝑟𝑡𝐹 ++ [ +𝑀𝑟𝑟 +𝑀𝑟𝑟𝐹 +] ++ [ +𝑀𝑠𝑠 +𝑀𝑠𝑠𝐹 +] ++ [ +𝑀𝑡𝑡 +𝑀𝑡𝑡𝐹 +] +⎟⎞ +⎠ +< FFCAP +BETA +If BETA is specified, the stress is multiplied by an exponential using ω defined in the +previous equations, +𝜎𝑑 = 𝜎exp(−𝛽𝜔). +For weld elements in an assembly , the failure criterion is evaluated using the +assembly cross section. If damage is not active, all elements will be deleted when the +failure criterion is met. If damage is active, then damage is calculated independently in +each element of the assembly. By default, elements of the assembly are deleted as +damage in each element is complete. If ASFF = 1, then failure and deletion of all +elements in the assembly will occur simultaneously when damage is complete in any +one of the elements. +TRUE_T +Weld elements and weld assemblies are tied to the mid-plane of shell materials and so +typically have a thickness that is half the sum of the thicknesses of the welded shell +sections. As a result, a weld under shear loading can be subject to an artificially large +moment which will be balanced by normal forces transferred through the tied contact. +These normal forces will cause the out-of-plane bending moment used in the failure +calculation to be artificially high. Inputting a TRUE_T that is smaller than the modeled +thickness, for example, 10%-30% of true thickness will scale down the moment or stress +that results from the balancing moment and provide more realistic failure calculations +for solid elements and weld assemblies. TRUE_T effects only the failure calculation, not +the weld element behavior. If TRUE_T = 0 or data is omitted, the modeled weld +element thickness is used. For OPT = 0, the two out-of-plane moments, 𝑀𝑠𝑠 and 𝑀𝑡𝑡 are +replaced by modified terms 𝑀̂𝑠𝑠 and 𝑀̂𝑡𝑡, as shown below: +[ +max(𝑁𝑟𝑟, 0) +𝑁𝑟𝑟𝐹 +] +] ++ [ +𝑁𝑟𝑠 +𝑁𝑟𝑠𝐹 ++ [ +𝑁𝑟𝑡 +𝑁𝑟𝑡𝐹 +] +] ++ [ +𝑀𝑟𝑟 +𝑀𝑟𝑟𝐹 ++ [ +𝑀̂𝑠𝑠 +𝑀𝑠𝑠𝐹 +] +] ++ [ +𝑀̂𝑡𝑡 +𝑀𝑡𝑡𝐹 +− 1 = 0 +𝑀̂𝑠𝑠 = 𝑀𝑠𝑠 − 𝑁𝑟𝑡(𝑡 − 𝑡true) +𝑀̂𝑡𝑡 = 𝑀𝑡𝑡 − 𝑁𝑟𝑠(𝑡 − 𝑡true) +In the above, 𝑡 is the element thickness and . 𝑡true is the TRUE_T parameter. For +OPT = 1, the same modification is done to the moments that contribute to the normal +stress, as shown below: +𝜎𝑟𝑟 = +𝑁𝑟𝑟 ++ +√𝑀̂𝑠𝑠 +2 + 𝑀̂ +𝑡𝑡 +Uniaxial option +A uniaxial stress option is available for solid and solid weld assemblies. It is invoked +by defining the elastic modulus, 𝐸 as a negative number where the absolute value of 𝐸 +is the desired value for 𝐸. The uniaxial option causes the two transverse stress terms to +be assumed to be zero throughout the calculation. This assumption eliminates parasitic +transverse stress that causes slow growth of plastic strain based damage. +The motivation for this option can be explained with a weld loaded in tension. Due to +Poisson’s effect, an element in tension would be expected to contract in the transverse +directions. However, because the weld nodes are constrained to the mid-plane of shell +elements, such contraction is only possible to the degree that that shell element +contracts. In other words, the uniaxial stress state cannot be represented by the weld. +For plastic strain based damage, this effect can be particularly apparent as it causes +tensile stress to continue to grow very large as the stress state becomes very nearly +triaxial tension. In this stress state, plastic strain grows very slowly so it appears that +damage calculation is failing to knock down the stress. By simply assuming that the +transverse stresses are zero, the plastic strain grows as expected and damage is much +more effective. +Material histories +The probability of failure in solid or beam spotwelds can be estimated by retrieving the +corresponding material histories for output to the d3plot database +*DEFINE_MATERIAL_HISTORIES Properties +Label +Attributes +Description +Instability +Damage +- +- +- +- +- +- +- A measure between 0 and 1 related to +how close the spotweld element is to fail +- Damage +in +the +spotweld +element +between 0 and 1 +These two labels are supported for all options (OPT and DMGOPT, including +assemblies and beams), except for user defined failure. The instability measure is the +maximum over time; namely, it gives the maximum value for a given element +throughout the simulation. If a damage option is invoked then damage will initiate and +increment when the instability reaches unity, and elements are not deleted until the +damage value reaches unity. If no damage option is invoked then the damage output is +always zero and elements will be deleted at the point when the instability measure +reaches unity. +*MAT_SPOTWELD_DAIMLERCHRYSLER +This is Material Type 100. The material model applies only to solid element type l. If +hourglass type 4 is specified then hourglass type 4 will be used, otherwise, hourglass +type 6 will be automatically assigned. Hourglass type 6 is preferred. +constraint +Spot weld elements may be placed between any two deformable shell surfaces and tied +*CONTACT_TIED_SURFACE_TO_SURFACE, which +with +eliminates the need to have adjacent nodes at spot weld locations. Spot weld failure is +modeled using this card and *DEFINE_CONNECTION_PROPERTIES data. Details of +the failure model can be found in Seeger, Feucht, Frank, Haufe, and Keding [2005]. +contact, +NOTE: It is advisable to include all spot welds, which pro- +vide the slave nodes, and spot welded materials, +which define the master segments, within a single +*CONTACT_TIED_SURFACE_TO_SURFACE inter- +face. This contact type uses constraint equations. If +multiple interfaces are treated independently, sig- +nificant problems can occur if such interfaces share +common nodes. An added benefit is that memory +usage can be substantially less with a single inter- +face +. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +Variable +EFAIL +Type +F +2 +RO +F +2 +3 +E +F +3 +4 +PR +F +4 +5 +6 +5 +6 +7 +DT +F +7 +8 +TFAIL +F +8 +NF +Card 3 +Variable +1 +RS +2 +3 +4 +5 +6 +7 +8 +ASFF +TRUE_T +CON_ID +JTOL +Type +F +I +F +F +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +DT +TFAIL +EFAIL +NF +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +Time step size for mass scaling, Δ𝑡. +Failure time if nonzero. If zero this option is ignored. +Effective plastic strain in weld material at failure. See remark +below. +Number of failure function evaluations stored for filtering by +time averaging. The default value is set to zero which is generally +recommended unless oscillatory resultant forces are observed in +the time history databases. Even though these welds should not +oscillate significantly, this option was added for consistency with +the other spot weld options. NF affects the storage since it is +necessary to store the failure terms. When NF is nonzero, the +resultants in the output databases are filtered. NF cannot exceed +30. +RS +ASFF +Rupture strain. See Remarks below. +Weld assembly simultaneous failure flag +EQ.0: Damaged elements fail individually. +EQ.1: Damaged elements fail when first reaches failure +criterion. +TRUE_T +True weld thickness for single hexahedron solid weld elements. +See comments below. +DESCRIPTION +Connection ID of *DEFINE_CONNECTION card. A negative +CON_ID deactivates failure, see comments below. +Tolerance value for relative volume change (default: JTOL = 0.01). +Solid element spotwelds with a Jacobian less than JTOL will be +eroded. + VARIABLE +CON_ID +JTOL +Remarks: +This weld material is modeled with isotropic hardening plasticity. The yield stress and +constant hardening modulus are assumed to be those of the welded shell elements as +defined in a *DEFINE_CONNECTION_PROPERTIES table. A failure function and +damage type is also defined by *DEFINE_CONNECTION_PROPERTIES data. The +interpretation of EFAIL and RS is determined by the choice of damage type. This is +discussed in remark 4 on *DEFINE_CONNECTION_PROPERTIES. +Solid weld elements are tied to the mid-plane of shell materials and so typically have a +thickness that is half the sum of the thicknesses of the welded shell sections. As a result, +a weld under shear loading can be subject to an artificially large moment which will be +balanced by normal forces transferred through the tied contact. These normal forces +will cause the normal term in the failure calculation to be artificially high. Inputting a +TRUE_T that is smaller than the modeled thickness, for example, 10%-30% of true +thickness will scale down the normal force that results from the balancing moment and +provide more realistic failure calculations. TRUE_T effects only the failure calculation, +not the weld element behavior. If TRUE_T = 0 or data is omitted, the modeled weld +element thickness is used. +For weld elements in an assembly , the failure criterion is evaluated using the +assembly cross section. If damage is not active, all elements will be deleted when the +failure criterion is met. If damage is active, then damage is calculated independently in +each element of the assembly. By default, elements of the assembly are deleted as +damage in each element is complete. If ASFF = 1, then failure and deletion of all +elements in the assembly will occur simultaneously when damage is complete in any +one of the elements. +Solid element force resultants for MAT_SPOTWELD are written to the spot weld force +file, swforc, and the file for element stresses and resultants for designated elements, +ELOUT. Also, spot weld failure data is written to the file, dcfail. +An option to deactivate weld failure is switched on by setting CON_ID to a negative +value where the absolute value of CON_ID becomes the connection ID. When weld +failure is deactivated, the failure function is evaluated and output to swforc and dcfail +but the weld retains its full strength. +*MAT_101 +is Material Type 101. +This + The GEPLASTIC_SRATE_2000a material model +characterizes General Electric's commercially available engineering thermoplastics +subjected to high strain rate events. This material model features the variation of yield +stress as a function of strain rate, cavitation effects of rubber modified materials and +automatic element deletion of either ductile or brittle materials. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +E +F +3 +4 +5 +6 +7 +8 +PR +RATESF +EDOT0 +ALPHA +F +4 +F +5 +F +6 +F +7 +8 +Variable +LCSS +LCFEPS +LCFSIG +LCE +Type +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young's Modulus. +Poisson's ratio. +RATESF +Constant in plastic strain rate equation. +EDOT0 +Reference strain rate +ALPHA +Pressure sensitivity factor +LCSS +Load curve ID or Table ID that defines the post yield material +behavior. The values of this stress-strain curve are the difference +of the yield stress and strain respectively. This means the first +values for both stress and strain should be zero. All subsequent +values will define softening or hardening. +Load curve ID that defines the plastic failure strain as a function +of strain rate. +Load curve ID that defines the Maximum principal failure stress +as a function of strain rate. +Load curve ID that defines the Unloading moduli as a function of +plastic strain. +*MAT_101 + VARIABLE +LCFEPS +LCFSIG +LCE +Remarks: +The constitutive model for this approach is: +𝜀̇𝑝 = 𝜀̇0exp{𝐴[𝜎 − 𝑆(𝜀𝑝)]} × exp(−𝑝𝛼𝐴) +where 𝜀̇0 and A are rate dependent yield stress parameters, 𝑆(𝜀𝑝) internal resistance +(strain hardening) and 𝛼 is a pressure dependence parameter. +In this material the yield stress may vary throughout the finite element model as a +function of strain rate and hydrostatic stress. Post yield stress behavior is captured in +material softening and hardening values. Finally, ductile or brittle failure measured by +plastic strain or maximum principal stress respectively is accounted for by automatic +element deletion. +Although this may be applied to a variety of engineering thermoplastics, GE Plastics +have constants available for use in a wide range of commercially available grades of +their engineering thermoplastics. +*MAT_INV_HYPERBOLIC_SIN_{OPTION} +This is Material Type 102. It allows the modeling of temperature and rate dependent +plasticity, Sheppard and Wright [1979]. +Available options include: + +THERMAL +such that the keyword card can appear as: +*MAT_INV_HYPERBOLIC_SIN or *MAT_102 +*MAT_INV_HYPERBOLIC_SIN_THERMAL or *MAT_102_T +Card 1 for option: + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +Card 2 for option: + Card 2 +1 +Variable +ALPHA +Type +F +2 +N +F +3 +E +F +3 +A +F +Card 1 for THERMAL option: + Card 1 +1 +2 +3 +Variable +MID +RO +ALPHA +Type +A8 +F +F +4 +PR +F +4 +Q +F +4 +N +F +5 +T +F +5 +G +F +5 +A +F +8 +6 +HC +F +7 +VP +F +6 +7 +8 +EPS0 +LCQ +F +I +6 +Q +F +7 +G +F +8 +EPSO +*MAT_INV_HYPERBOLIC_SIN + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCE +LCPR +LCCTE +Type +F +F +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +E +PR +T +HC +VP +Mass density. +Young’s Modulus. +Poisson’s ratio +Initial Temperature. +Heat generation coefficient. +Formulation for rate effects: +EQ.0.0: Scale yield stress (default) +EQ.1.0: Viscoplastic formulation. +ALPHA +α, see Remarks. Not to be confused with coefficient of thermal +expansion. +N +A +Q +G +EPS0 +LCQ +See Remarks. +See Remarks. +See Remarks. +See Remarks. +Minimum strain rate considered in calculating Z. +ID of curve specifying parameter Q. +GT.0: Q as function of plastic strain. +LT.0: Q as function of temperature. +VARIABLE +DESCRIPTION +ID of curve defining Young’s Modulus vs. temperature. +ID of curve defining Poisson’s ratio vs. temperature. +ID of curve defining coefficient of thermal expansion vs. +temperature. +LCE +LCPR +LCCTE +Remarks: +Resistance to deformation is both temperature and strain rate dependent. The flow +stress equation is: +𝜎 = +sinh−1 +⎡ +⎢ +⎣ +( +) +⎤ +⎥ +⎦ +where 𝑍, the Zener-Holloman temperature compensated strain rate, is: +𝑍 = max(𝜀̇,EPS0) × exp ( +GT +) +The units of the material constitutive constants are as follows: 𝐴 (1/sec), 𝑁 +(dimensionless), 𝛼 (1/MPa), the activation energy for flow, 𝑄(J/mol), and the universal +gas constant, 𝐺 (J/mol K). The value of 𝐺 will only vary with the unit system chosen. +Typically it will be either 8.3144 J/mol ∞ K, or 40.8825 lb in/mol ∞ R. +The final equation necessary to complete our description of high strain rate deformation +is one that allows us to compute the temperature change during the deformation. In the +absence of a couples thermo-mechanical finite element code we assume adiabatic +temperature change and follow the empirical assumption that 90-95% of the plastic +work is dissipated as heat. Thus the heat generation coefficient is +where 𝜌 is the density of the material and 𝐶𝑣 is the specific heat. +HC ≈ +0.9 +𝜌𝐶𝑣 +*MAT_ANISOTROPIC_VISCOPLASTIC +This is Material Type 103. This anisotropic-viscoplastic material model applies to shell +and brick elements. The material constants may be fit directly or, if desired, stress +versus strain data may be input and a least squares fit will be performed by LS-DYNA +to determine the constants. Kinematic or isotopic or a combination of kinematic and +isotropic hardening may be used. A detailed description of this model can be found in +the following references: Berstad, Langseth, and Hopperstad [1994]; Hopperstad and +Remseth [1995]; and Berstad [1996]. Failure is based on effective plastic strain or by a +user defined subroutine. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +E +F +3 +4 +PR +F +4 +5 +6 +7 +8 +SIGY +FLAG +LCSS +ALPHA +F +5 +F +6 +F +7 +F +8 +Variable +QR1 +CR1 +QR2 +CR2 +QX1 +CX1 +QX2 +CX2 +Type +F + Card 3 +Variable +1 +VK +Type +F + Card 4 +1 +F +2 +F +3 +F +4 +F +5 +VM +R00 or F R45 or G R90 or H +F +2 +F +3 +F +4 +F +5 +F +6 +L +F +6 +F +7 +M +F +7 +F +8 +N +F +8 +Variable +AOPT +FAIL +NUMINT +MACF +Type +F +F +F +Variable +1 +XP +Type +F + Card 6 +Variable +1 +V1 +Type +F +2 +YP +F +2 +V2 +F +3 +ZP +F +3 +V3 +F +4 +A1 +F +4 +D1 +F +5 +A2 +F +5 +D2 +F +6 +A3 +F +6 +D3 +F + VARIABLE +DESCRIPTION +*MAT_103 +7 +8 +7 +8 +BETA +F +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus +Poisson’s ratio +SIGY +Initial yield stress +FLAG +Flag +*MAT_ANISOTROPIC_VISCOPLASTIC +DESCRIPTION +EQ.0: Give all material parameters +EQ.1: Material parameters parameters 𝑄𝑟1, 𝐶𝑟1, 𝑄𝑟2, and 𝐶𝑟2 for +pure isotropic hardening (𝛼 = 1) are determined by a +least squares fit to the curve or table specified by the +variable LCSS. If 𝛼 is input as less than 1, 𝑄𝑟1 and 𝑄𝑟2 +are then modified by multiplying them by the factor 𝛼, +while the factors 𝑄𝑥1 and 𝑄𝑥2 are taken as the product of +the original parameters 𝑄𝑟1and 𝑄𝑟2, resp., for pure iso- +tropic hardening and the factor (1 − 𝛼). 𝐶𝑥1 is set equal +to 𝐶𝑟1 and 𝐶𝑥2 is set equal to 𝐶𝑟2. 𝛼 is input as variable +ALPHA on Card 1 in columns 71-80. +EQ.2: Use load curve directly, i.e., no fitting is required for the +parameters 𝑄𝑟1, 𝐶𝑟1, 𝑄𝑟2, and 𝐶𝑟2. A table is not allowed +and only isotropic hardening is implemented. +EQ.4: Use table definition directly, no fitting is required and +the values for 𝑄𝑟1, 𝐶𝑟1, 𝑄𝑟2, 𝐶𝑟2, 𝑉𝑘, and 𝑉𝑚 are ignored. +Only isotropic hardening is implemented, and this op- +tion is only available for solids. +LCSS +Load curve ID or Table ID. +Case 1: LCSS is a Load Curve ID. The load curve ID defines +effective stress versus effective plastic strain. Card 2 is ignored +with this option. For this load curve case viscoplasticity is +modeled when the coefficients 𝑉𝑘 and 𝑉𝑚 are provided. +Case 2: LCSS is a Table ID. Table consists of stress versuses +effective plastic strain curves indexed by strain rate. See Figure +M24-1. +FLAG.EQ.1: Table is used to calculate the coefficients 𝑉𝑘 and +𝑉𝑚. +FLAG.EQ.4: Table is interpolated and used directly. This +option is available only for solid elements. +ALPHA +𝛼 distribution of hardening used in the curve-fitting. 𝛼 = 0 pure +kinematic hardening and 𝛼 = 1 provides pure isotropic hardening +QR1 +CR1 +Isotropic hardening parameter 𝑄𝑟1 +Isotropic hardening parameter 𝐶𝑟1 +VARIABLE +DESCRIPTION +QR2 +CR2 +QX1 +CX1 +QX2 +CX2 +VK +VM +R00 +R45 +R90 +F +G +H +L +M +N +Isotropic hardening parameter 𝑄𝑟2 +Isotropic hardening parameter 𝐶𝑟2 +Kinematic hardening parameter 𝑄𝜒1 +Kinematic hardening parameter 𝐶𝜒1 +Kinematic hardening parameter 𝑄𝜒2 +Kinematic hardening parameter 𝐶𝜒2 +Viscous material parameter 𝑉𝑘 +Viscous material parameter 𝑉𝑚 +𝑅00 for shell (Default = 1.0) +𝑅45 for shell (Default = 1.0) +𝑅90 for shell (Default = 1.0) +𝐹 for brick (Default = 1/2) +𝐺 for brick (Default = 1/2) +𝐻 for brick (Default = 1/2) +𝐿 for brick (Default = 3/2) +𝑀 for brick (Default = 3/2) +𝑁 for brick (Default = 3/2) +AOPT +*MAT_ANISOTROPIC_VISCOPLASTIC +DESCRIPTION +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then, for shells only, rotated about +the shell element normal by an angle BETA. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the a-direction. This option is for solid +elements only. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector v, and +an originating point, P, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +FAIL +Failure flag. +LT.0.0: User defined failure subroutine is called to determine +failure. This is subroutine named, MATUSR_103, in +dyn21.f. +EQ.0.0: Failure is not considered. This option is recommended +if failure is not of interest since many calculations will +be saved. +GT.0.0: Plastic strain to failure. When the plastic strain reaches +this value, the element is deleted from the calculation. +VARIABLE +NUMINT +DESCRIPTION +Number of integration points which must fail before element +deletion. If zero, all points must fail. This option applies to shell +elements only. For the case of one point shells, NUMINT should +be set to a value that is less than the number of through thickness +integration points. Nonphysical stretching can sometimes appear +in the results if all integration points have failed except for one +point away from the midsurface. This is due to the fact that +unconstrained nodal rotations will prevent strains +from +developing at the remaining integration point. In fully integrated +shells, similar problems can occur. +MACF +Material axes change flag for brick elements: +EQ.1: No change, default, +EQ.2: switch material axes 𝑎 and 𝑏, +EQ.3: switch material axes 𝑎 and 𝑐, +EQ.4: switch material axes 𝑏 and 𝑐. +XP, YP, ZP +𝑥𝑝, 𝑦𝑝, 𝑧𝑝, define coordinates of point 𝐩 for AOPT = 1 and 4. +A1, A2, A3 +𝑎1, 𝑎2, 𝑎3, define components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +𝑣1, 𝑣2, 𝑣3 define components of vector 𝐯 for AOPT = 3 and 4. +D1, D2, D3 +𝑑1, 𝑑2, 𝑑3, define components of vector 𝐝 for AOPT = 2. +BETA +Material angle in degrees for AOPT = 0 (shells only) and +AOPT = 3. BETA may be overridden on the element card, see +*ELEMENT_SHELL_BETA and *ELEMENT_SOLID_ORTHO. +Remarks: +The uniaxial stress-strain curve is given on the following form +𝜎(𝜀eff +𝑝 , 𝜀̇eff +𝑝 ) = 𝜎0 + 𝑄𝑟1[(1 − exp(−𝐶𝑟1𝜀eff ++ 𝑄𝜒1[(1 − exp(−𝐶𝜒1𝜀eff +𝑝 ))] + 𝑄𝑟2[1 − exp(−𝐶𝑟2𝜀eff +𝑝 ))] + 𝑄𝜒2[(1 − exp(−𝐶𝜒2𝜀eff +𝑝 )] +𝑝 ))] + 𝑉𝑘𝜀̇eff +𝑝 𝑉𝑚 +For bricks the following yield criteria is used +𝐹(𝜎22 − 𝜎33)2 + 𝐺(𝜎33 − 𝜎11)2 + 𝐻(𝜎11 − 𝜎22)2 + 2𝐿𝜎23 +𝑝 )] += [𝜎(𝜀eff +𝑝 , 𝜀̇eff +2 + 2𝑀𝜎31 +2 + 2𝑁𝜎12 +𝑝 is the effective plastic strain and 𝜀̇eff +𝑝 is the effective plastic strain rate. For +where 𝜀eff +shells the anisotropic behavior is given by 𝑅00, 𝑅45 and 𝑅90. The model will work when +the three first parameters in card 3 are given values. When 𝑉𝑘 = 0 the material will +behave elasto-plastically. Default values are given by: +𝐹 = 𝐺 = 𝐻 = +𝐿 = 𝑀 = 𝑁 = +𝑅00 = 𝑅45 = 𝑅90 = 1 +Strain rate of accounted for using the Cowper and Symonds model which, e.g., model 3, +scales the yield stress with the factor: +⎜⎛ +⎝ +To convert these constants set the viscoelastic constants, 𝑉𝑘 and 𝑉𝑚, to the following +values: +1 + +𝑝⁄ +𝜀̇eff +⎟⎞ +𝐶 ⎠ +) +𝑉𝑘 = ( +𝑉𝑚 = +If LCSS is nonzero, substitute the initial, quasi-static yield stress for SIGY in the +equation for 𝑉𝑘 above. +This model properly treats rate effects. The viscoplastic rate formulation is an option in +other plasticity models in LS-DYNA, e.g., mat_3 and mat_24, invoked by setting the +parameter VP to 1. +*MAT_103_P +This is Material Type 103_P. This anisotropic-plastic material model is a simplified +version of the MAT_ANISOTROPIC_VISCOPLASTIC above. This material model +applies only to shell elements. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +E +F +3 +4 +PR +F +4 +Variable +QR1 +CR1 +QR2 +CR2 +Type +F + Card 3 +1 +F +2 +F +3 +F +4 +5 +6 +7 +8 +SIGY +LCSS +F +5 +F +6 +7 +8 +5 +6 +7 +8 +Variable +R00 +R45 +R90 +S11 +S22 +S33 +S12 +Type +F + Card 4 +1 +Variable +AOPT +Type +F + Card 5 +Variable +1 +XP +Type +F +F +2 +2 +YP +F +F +3 +3 +ZP +F +F +4 +4 +A1 +F +F +5 +5 +A2 +F +F +6 +6 +A3 +F +F +7 +8 +7 +Card 6 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +BETA +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +SIGY +LCSS +QR1 +CR1 +QR2 +CR2 +R00 +R45 +R90 +S11 +S22 +S33 +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus +Poisson’s ratio +Initial yield stress +Load curve ID. The load curve ID defines effective stress versus +effective plastic strain. Card 2 is ignored with this option. +Isotropic hardening parameter 𝑄𝑟1 +Isotropic hardening parameter 𝐶𝑟1 +Isotropic hardening parameter 𝑄𝑟2 +Isotropic hardening parameter 𝐶𝑟2 +𝑅00 for anisotropic hardening +𝑅45 for anisotropic hardening +𝑅90 for anisotropic hardening +Yield stress in local 𝑥-direction. This input is ignored if +(𝑅00, 𝑅45, 𝑅90) > 0. +Yield stress in local 𝑦-direction. This input is ignored if +(𝑅00, 𝑅45, 𝑅90) > 0. +Yield stress in local 𝑧-direction. This input is ignored if +(𝑅00, 𝑅45, 𝑅90) > 0. +VARIABLE +DESCRIPTION +S12 +AOPT +Yield stress in local -direction. This input is ignored if +(𝑅00, 𝑅45, 𝑅90) > 0. +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the shell ele- +ment normal by an angle BETA. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +XP, YP, ZP +𝑥𝑝, 𝑦𝑝, 𝑧𝑝 define coordinates of point 𝐩 for AOPT = 1 and 4. +A1, A2, A3 +𝑎1, 𝑎2, 𝑎3 define components of vector 𝐚 for AOPT = 2. +D1, D2, D3 +𝑑1, 𝑑2, 𝑑3 define components of vector 𝐝 for AOPT = 2. +V1, V2, V3 +𝑣1, 𝑣2, 𝑣3 define components of vector 𝐯 for AOPT = 3 and 4. +BETA +Material angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA. +Remarks: +If no load curve is defined for the effective stress versus effective plastic strain, the +uniaxial stress-strain curve is given on the following form +𝜎(𝜀eff +𝑝 ) = 𝜎0 + 𝑄𝑟1[1 − exp(−𝐶𝑟1𝜀eff +𝑝 )] + 𝑄𝑟2[1 − exp(−𝐶𝑟2𝜀eff +𝑝 )] +𝑝 is the effective plastic strain. For shells the anisotropic behavior is given by +where 𝜀eff +𝑅00, 𝑅45 and 𝑅90, or the yield stress in the different direction. Default values are given +by: +if the variables R00, R45, R90, S11, S22, S33 and S12 are set to zero. +𝑅00 = 𝑅45 = 𝑅90 = 1 +*MAT_104 +This is Material Type 104. This is a continuum damage mechanics (CDM) model which +includes anisotropy and viscoplasticity. The CDM model applies to shell, thick shell, +and brick elements. A more detailed description of this model can be found in the +paper by Berstad, Hopperstad, Lademo, and Malo [1999]. This material model can also +model anisotropic damage behavior by setting the FLAG to -1 in Card 2. +3 +E +F +3 +Q2 +F +3 +4 +PR +F +4 +C2 +F +4 + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +2 +C1 +F +2 + Card 2 +Variable +1 +Q1 +Type +F + Card 3 +Variable +1 +VK +Type +F + Card 4 +1 +VM +R00 or F R45 or G R90 or H +F +2 +F +3 +F +4 +Variable +AOPT +CPH +MACF +Type +F +F +I +5 +6 +7 +8 +SIGY +LCSS +LCDS +F +5 +6 +7 +8 +EPSD +S or EPSR +DC +FLAG +F +5 +F +5 +Y0 +F +F +6 +L +F +6 +F +7 +M +F +7 +F +8 +N +F +8 +ALPHA +THETA +ETA +F +F +Variable +1 +XP +Type +F + Card 6 +Variable +1 +V1 +Type +F +2 +YP +F +2 +V2 +F +3 +ZP +F +3 +V3 +F +4 +A1 +F +4 +D1 +F +5 +A2 +F +5 +D2 +F +6 +A3 +F +6 +D3 +F +*MAT_DAMAGE_1 +7 +8 +7 +8 +BETA +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +SIGY +LCSS +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus +Poisson’s ratio +Initial yield stress, 𝜎0 +Load curve ID defining effective stress versus effective plastic +strain. Isotropic hardening parameters on Card 2 are ignored +with this option. +LCDS +Load curve ID defining nonlinear damage curve. For FLAG = -1. +Q1 +C1 +Q2 +C2 +EPSD +S +Isotropic hardening parameter 𝑄1 +Isotropic hardening parameter 𝐶1 +Isotropic hardening parameter 𝑄2 +Isotropic hardening parameter 𝐶2 +Damage threshold 𝜀eff,d +material softening begins. (Default = 0.0) +. Damage effective plastic strain when +Damage material constant 𝑆. (Default = +𝜎0 +200). For FLAG ≥ 0. +VARIABLE +DESCRIPTION +EPSR +DC +Effective plastic strain at which material ruptures (logarithmic). +For FLAG = -1. +Critical damage value 𝐷𝐶. When the damage value 𝐷 reaches this +value, the element is deleted from the calculation. (Default = 0.5) +For FLAG ≥ 0. +FLAG +Flag +EQ.-1: Anisotropic damage +EQ.0: Standard isotropic damage (default) +EQ.1: Standard isotropic damage plus strain localization +check (only for shell elements) +EQ.10: Enhanced isotropic damage +EQ.11: Enhanced isotropic damage plus strain localization +check (only for shell elements) +VK +VM +R00 +R45 +R90 +F +G +H +L +M +N +Viscous material parameter 𝑉𝑘 +Viscous material parameter 𝑉𝑚 +𝑅00 for shell (Default = 1.0) +𝑅45 for shell (Default = 1.0) +𝑅90 for shell (Default = 1.0) +F for brick (Default = 1/2) +G for brick (Default = 1/2) +H for brick (Default = 1/2) +L for brick (Default = 3/2) +M for brick (Default = 3/2) +N for brick (Default = 3/2) +AOPT +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then, for shells only, rotated about +*MAT_DAMAGE_1 +DESCRIPTION +the shell element normal by an angle BETA. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the a-direction. This option is for solid +elements only. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector v, and +an originating point, P, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +CPH +Microdefects closure parameter h +(FLAG ≥ 10). +for enhanced damage +MACF +Material axes change flag for brick elements: +EQ.1: No change, default, +EQ.2: switch material axes a and b, +EQ.3: switch material axes a and c, +EQ.4: switch material axes b and c. +Y0 +Initial damage energy release rate Y0 for enhanced damage +(FLAG ≥ 10). +ALPHA +Exponent 𝛼 for enhanced damage (FLAG ≥ 10) +THETA +Exponent 𝜃 for enhanced damage (FLAG ≥ 10) +ETA +Exponent 𝜂 for enhanced damage (FLAG ≥ 10) +VARIABLE +DESCRIPTION +XP, YP, ZP +𝑥𝑝, 𝑦𝑝, 𝑧𝑝: define coordinates of point 𝐩 for AOPT = 1 and 4 +A1, A2, A3 +𝑎1, 𝑎2, 𝑎3: define components of vector 𝐚 for AOPT = 2 +D1, D2, D3 +𝑑1, 𝑑2, 𝑑3: define components of vector 𝐝 for AOPT = 2 +V1, V2, V3 +𝑣1, 𝑣2, 𝑣3: define components of vector 𝐯 for AOPT = 3 and 4 +BETA +Μaterial angle in degrees for AOPT = 0 (shells only) and +AOPT = 3. BETA may be overridden on the element card, see +*ELEMENT_SHELL_BETA and *ELEMENT_SOLID_ORTHO. +Remarks: +Standard isotropic damage model (FLAG = 0 or 1). The Continuum Damage +Mechanics (CDM) model is based on an approach proposed by Lemaitre [1992]. The +effective stress 𝜎̃ , which is the stress calculated over the section that effectively resist the +forces, reads +𝜎̃ = +1 − 𝐷 +where 𝐷 is the damage variable. The evolution equation for the damage variable is +defined as +𝐷̇ = +⎧ 0 +{ +⎨ +{ +⎩ + 𝜀̇eff +for +for +𝑝 ≤ 𝜀eff,d +𝜀eff +𝑝 > 𝜀eff,d +𝜀eff +and 𝜎1 > 0 +where 𝜀eff,d +𝜎1 is the maximum principal stress. The damage energy density release rate is + is the damage threshold, 𝑆 is the so-called damage energy release rate and +𝑌 = +𝐞𝐞: 𝐂: 𝐞𝐞 = +2 𝑅𝑣 +𝜎𝑣𝑚 +2𝐸(1 − 𝐷)2 +where 𝐸 is Young’s modulus and 𝜎𝑣𝑚 is the equivalent von Mises stress. The triaxiality +function 𝑅𝑣 is defined as +𝑅𝑣 = +(1 + 𝜈) + 3(1 − 2𝜈) ( +𝜎𝐻 +𝜎𝑣𝑚 +) +with Poisson’s ratio 𝜈 and hydrostatic stress 𝜎𝐻. +Enhanced isotropic damage model (FLAG = 10 or 11). A more sophisticated damage +model including crack closure effects (reduced damage under compression) and more +flexibility in stress state dependence and functional expressions is invoked by setting +FLAG = 10 or 11. The corresponding evolution equation for the damage variable is +defined as +𝐷̇ = ( +2𝜏max +𝜎𝑣𝑚 +) + ⟨ +𝑌 − 𝑌0 +⟩ +𝑝 + (1 − 𝐷)1−𝜃 𝜀̇eff +where 𝜏max is the maximum shear stress, 𝑌0 is the initial damage energy release rate +and 𝜂, 𝛼, and 𝜃 are additional material constants. 〈 〉 are the Macauley brackets. The +damage energy density release rate is +𝑌 = +1 + 𝜈 +2𝐸 +(∑(〈𝜎̃𝑖〉2 + ℎ〈−𝜎̃𝑖〉2) +) − +𝑖=1 +2𝐸 +(〈𝜎̃𝐻〉2 + ℎ〈−𝜎̃𝐻〉2) +where 𝜎̃𝑖 are the principal effective stresses and h is the microdefects closure parameter +that accounts for different damage behavior in tension and compression. A value of +ℎ ≈ 0.2 is typically observed in many experiments as stated in Lemaitre [2000]. A +parameter set of ℎ = 1, 𝑌0 = 0, 𝛼 = 1, 𝜃 = 1, and 𝜂 = 0 should give the same results as +the standard isotropic damage model (FLAG = 0/1) with 𝜀eff,d += 0 as long as 𝜎1 > 0. +Strain localization check (FLAG = 1 or 11). In order to add strain localization +computation to the damage models above, parameter FLAG should be set to 1 +(standard damage) or 11 (enhanced damage). An acoustic tensor based bifurcation +criterion is checked and history variable no. 4 is set to 1.0 if strain localization is +indicated. Only available for shell elements. +Anisotropic damage model (FLAG = -1). At each thickness integration points, an +anisotropic damage law acts on the plane stress tensor in the directions of the principal +total shell strains, 𝜀1 and 𝜀2, as follows: +𝜎11 = [1 − 𝐷1(𝜀1)]𝜎110 +𝜎22 = [1 − 𝐷2(𝜀2)]𝜎220 +𝜎12 = [1 − +𝐷1 + 𝐷2 +] 𝜎120 +The transverse plate shear stresses in the principal strain directions are assumed to be +damaged as follows: +𝜎13 = (1 − 𝐷1/2)𝜎130 +𝜎23 = (1 − 𝐷2/2)𝜎230 +In the anisotropic damage formulation, 𝐷1(𝜀1) and 𝐷2(𝜀2) are anisotropic damage +functions for the loading directions 1 and 2, respectively. Stresses 𝜎110, 𝜎220,𝜎120, 𝜎130 +and 𝜎230 are stresses in the principal shell strain directions as calculated from the +undamaged elastic-plastic material behavior. The strains 𝜀1 and 𝜀2 are the magnitude of +the principal strains calculated upon reaching the damage thresholds. Damage can only +develop for tensile stresses, and the damage functions 𝐷1(𝜀1) and 𝐷2(𝜀2)are identical to +zero for negative strains 𝜀1 and 𝜀2. The principal strain directions are fixed within an +integration point as soon as either principal strain exceeds the initial threshold strain in +tension. A more detailed description of the damage evolution for this material model is +given in the description of Material 81. +Anisotropic viscoplasticity. The uniaxial stress-strain curve is given in the following +form +𝜎(𝑟, 𝜀̇eff +𝑝 ) = 𝜎0 + 𝑄1[1 − exp(−𝐶1𝑟)] + 𝑄2[1 − exp(−𝐶2𝑟)] + 𝑉𝑘𝜀̇eff +𝑝 𝑉𝑚 +where r is the damage accumulated plastic strain, which can be calculated by +𝑟 ̇ = 𝜀̇eff +For bricks the following yield criterion associated with the Hill criterion is used +𝑝 (1 − 𝐷) +𝐹(𝜎̃22 − 𝜎̃33)2 + 𝐺(𝜎̃33 − 𝜎̃11)2 + 𝐻(𝜎̃11 − 𝜎̃22)2 + 2𝐿𝜎̃23 +2 + 2𝑀𝜎̃31 +2 + 2𝑁𝜎̃12 +2 = 𝜎(𝑟, 𝜀̇eff +𝑝 ) +𝑝 is the effective viscoplastic +where 𝑟 is the damage effective viscoplastic strain and 𝜀̇eff +strain rate. For shells the anisotropic behavior is given by the R-values: 𝑅00, 𝑅45, and +𝑅90. When 𝑉𝑘 = 0 the material will behave as an elastoplastic material without rate +effects. Default values for the anisotropic constants are given by: +𝐹 = 𝐺 = 𝐻 = +𝐿 = 𝑀 = 𝑁 = +𝑅00 = 𝑅45 = 𝑅90 = 1 +so that isotropic behavior is obtained. +Strain rate is accounted for using the Cowper and Symonds model which scales the +yield stress with the factor: +1 + ( +𝑝⁄ +) +𝜀̇ +To convert these constants, set the viscoelastic constants, 𝑉𝑘 and 𝑉𝑚, to the following +values: +𝑉𝑘 = 𝜎 ( +) +𝑉𝑚 = +F +0 +8 +*MAT_105 +*MAT_DAMAGE_2 +*MAT_DAMAGE_2 +This is Material Type 105. This is an elastic viscoplastic material model combined with +continuum damage mechanics (CDM). This material model applies to shell, thick shell, +and brick elements. The elastoplastic behavior is described in the description of +material model 24. A more detailed description of the CDM model is given in the +description of material model 104 above. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +6 +7 +8 +SIGY +ETAN +FAIL +TDEL +F +F +F +Default +none +none +none +none +none +0.0 +10.E+20 + Card 2 +Variable +Type +Default +1 +C +F +0 + Card 3 +1 +Variable +EPSD +Type +F +2 +P +F +0 +2 +S +F +3 +4 +5 +6 +7 +LCSS +LCSR +F +0 +4 +F +0 +3 +DC +F +5 +6 +7 +8 +Default +none +none +none +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EPS1 +EPS2 +EPS3 +EPS4 +EPS5 +EPS6 +EPS7 +EPS8 +Type +Default +F +0 + Card 5 +1 +F +0 +2 +F +0 +3 +F +0 +4 +F +0 +5 +F +0 +6 +F +0 +7 +F +0 +8 +Variable +ES1 +ES2 +ES3 +ES4 +ES5 +ES6 +ES7 +ES8 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +SIGY +ETAN +FAIL +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +Yield stress. +Tangent modulus, ignored if (LCSS.GT.0) is defined. +Failure flag. +EQ.0.0: Failure due to plastic strain is not considered. +GT.0.0: Plastic strain to failure. When the plastic strain reaches +this value, the element is deleted from the calculation. +TDEL +Minimum time step size for automatic element deletion. +C +P +Strain rate parameter, C, see formula below. +Strain rate parameter, P, see formula below. +LCSS +LCSR +EPSD +S +DC +*MAT_DAMAGE_2 +DESCRIPTION +Load curve ID or Table ID. Load curve ID defining effective +stress versus effective plastic strain. If defined EPS1 - EPS8 and +ES1 - ES8 are ignored. The table ID defines for each strain rate +value a load curve ID giving the stress versus effective plastic +strain for that rate, See Figure M24-1. The stress versus effective +plastic strain curve for the lowest value of strain rate is used if the +strain rate falls below the minimum value. Likewise, the stress +versus effective plastic strain curve for the highest value of strain +rate is used if the strain rate exceeds the maximum value. The +strain rate parameters: C and P; the curve ID, LCSR; EPS1 - EPS8 +and ES1 - ES8 are ignored if a Table ID is defined. +Load curve ID defining strain rate scaling effect on yield stress. +Damage threshold 𝑟𝑑 Damage effective plastic strain when +material softening begin. (Default = 0.0) +Damage material constant 𝑆. (Default = +𝜎0 +200) +Critical damage value 𝐷𝐶. When the damage value 𝐷 reaches +this value, +the calculation. +(Default = 0.5) +the element +is deleted +from +EPS1 - EPS8 +Effective plastic strain values (optional if SIGY is defined). At +least 2 points should be defined. +ES1 - ES8 +Corresponding yield stress values to EPS1 - EPS8. +Remarks: +The stress-strain behavior may be treated by a bilinear curve by defining the tangent +modulus, ETAN. Alternately, a curve similar to that shown in Figure M10-1 is expected +to be defined by (EPS1,ES1) - (EPS8,ES8); however, an effective stress versus effective +plastic strain curve ID (LCSS) may be input instead if eight points are insufficient. The +cost is roughly the same for either approach. The most general approach is to use the +table definition with table ID, LCSR, discussed below. +Three options to account for strain rate effects are possible. +1. Strain rate may be accounted for using the Cowper and Symonds model which +scales the yield stress with the factor +1 + ( +𝑝⁄ +) +𝜀̇ +where 𝜀̇ is the strain rate, 𝜀̇ = √𝜀̇𝑖𝑗𝜀̇𝑖𝑗 +2. For complete generality a load curve (LCSR) to scale the yield stress may be +input instead. In this curve the scale factor versus strain rate is defined. +3. +If different stress versus strain curves can be provided for various strain rates, +the option using the reference to a table (LCSS) can be used. Then the table +input in *DEFINE_TABLE has to be used, see Figure M24-1 +A fully viscoplastic formulation is used in this model. +*MAT_ELASTIC_VISCOPLASTIC_THERMAL +This is Material Type 106. This is an elastic viscoplastic material with thermal effects. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +E +F +3 +4 +PR +F +4 +5 +6 +7 +8 +SIGY +ALPHA +LCSS +FAIL +F +5 +F +6 +F +7 +F +8 +Variable +QR1 +CR1 +QR2 +CR2 +QX1 +CX1 +QX2 +CX2 +Type +F + Card 3 +Variable +Type +1 +C +F + Card 4 +1 +F +2 +P +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +LCE +LCPR +LCSIGY +LCR +LCX +LCALPH +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +LCC +LCP +TREF +LCFAIL +Type +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus +Poisson’s ratio +VARIABLE +DESCRIPTION +SIGY +LCSS +Initial yield stress +Load curve ID or Table ID. The load curve ID defines effective +stress versus effective plastic strain. The table ID defines for each +temperature value a load curve ID giving the stress versus +effective plastic strain for that temperature (DEFINE_TABLE) or +it defines for each temperature value a table ID which defines for +each strain rate a load curve ID giving the stress versus effective +plastic strain (DEFINE_TABLE_3D). The stress versus effective +plastic strain curve for the lowest value of temperature or strain +rate is used if the temperature or strain rate falls below the +minimum value. Likewise, maximum values cannot be exceeded. +Card 2 is ignored with this option. +FAIL +Effective plastic failure strain for erosion. +ALPHA +Coefficient of thermal expansion. +QR1 +CR1 +QR2 +CR2 +QX1 +CX1 +QX2 +CX2 +C +P +LCE +Isotropic hardening parameter 𝑄𝑟1 +Isotropic hardening parameter 𝐶𝑟1 +Isotropic hardening parameter 𝑄𝑟2 +Isotropic hardening parameter 𝐶𝑟2 +Kinematic hardening parameter 𝑄𝜒1 +Kinematic hardening parameter 𝐶𝜒1 +Kinematic hardening parameter 𝑄𝜒2 +Kinematic hardening parameter 𝐶𝜒2 +Viscous material parameter 𝐶 +Viscous material parameter 𝑃 +Load curve defining Young's modulus as a function of +temperature. +E on card 1 is ignored with this option. +LCPR +Load curve defining Poisson's ratio as a function of temperature. +PR on card 1 is ignored with this option. +LCSIGY +*MAT_ELASTIC_VISCOPLASTIC_THERMAL +DESCRIPTION +Load curve defining the initial yield stress as a function of +temperature. SIGY on card 1 is ignored with this option. +LCR +LCX +Load curve for scaling the isotropic hardening parameters QR1 +and QR2 or the stress given by the load curve LCSS as a function +of temperature. +Load curve for scaling the kinematic hardening parameters QX1 +and QX2 as a function of temperature. +LCALPH +Load curve ID defining the instantaneous coefficient of thermal +expansion as a function of temperature: +𝑑𝜀𝑖𝑗 +thermal = 𝛼(𝑇)𝑑𝑇𝛿𝑖𝑗 +ALPHA on card 1 is ignored with this option. If LCALPH is +defined as the negative of the load curve ID, the curve is assumed +to define the coefficient relative to a reference temperature, TREF +below, such that the total thermal strain is give by +thermal = 𝛼(𝑇)(𝑇 − 𝑇ref)𝛿𝑖𝑗 +𝜀𝑖𝑗 +LCC +LCP +TREF +Load curve for scaling the viscous material parameter C as a +function of temperature. +Load curve for scaling the viscous material parameter P as a +function of temperature. +Reference temperature required if and only if LCALPH is given +with a negative curve ID. +LCFAIL +Load curve defining the plastic failure strain as a function of +temperature. FAIL on card 1 is ignored with this option. +Remarks: +If LCSS is not given any value the uniaxial stress-strain curve has the form +𝑝 )] +𝑝 )] + 𝑄𝜒2[1 − exp(−𝐶𝜒2𝜀eff +𝑝 ) = 𝜎0 + 𝑄𝑟1[1 − exp(−𝐶𝑟1𝜀eff +𝑝 )] + 𝑄𝑟2[1 − exp(−𝐶𝑟2𝜀eff ++ 𝑄𝜒1[1 − exp(−𝐶𝜒1𝜀eff +𝜎(𝜀eff +𝑝 )] +Viscous effects are accounted for using the Cowper and Symonds model, which scales +the yield stress with the factor: +1 + +𝑝⁄ +. +𝜀̇eff +⎟⎞ +𝐶 ⎠ +⎜⎛ +⎝ +*MAT_MODIFIED_JOHNSON_COOK +This is Material Type 107. Adiabatic heating is included in the material formulation. +Material type 107 is not intended for use in a coupled thermal-mechanical analysis or in +a mechanical analysis where temperature is prescribed using *LOAD_THERMAL. +Define the following two cards with general material parameters + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +Variable +E0DOT +Type +F +2 +RO +F +2 +Tr +F +3 +E +F +3 +Tm +F +4 +PR +F +4 +T0 +F +5 +6 +BETA +XS1 +F +5 +F +6 +FLAG1 +FLAG2 +F +F +7 +CP +F +7 +8 +ALPHA +F +8 +Card 3 for Modified Johnson-Cook Constitutive Relation. This format is used when +FLAG1 = 0. + Card 3 +Variable +Type +1 +A +F +2 +B +F +3 +N +F +4 +C +F +5 +m +F +6 +7 +8 +Card 4 for Modified Johnson-Cook Constitutive Relation. This format is used when +FLAG1 = 0. + Card 4 +Variable +1 +Q1 +Type +F +2 +C1 +F +3 +Q2 +F +4 +C2 +F +5 +6 +7 +Card 3 for Modified Zerilli-Armstrong Constitutive Relation. This format is used +when FLAG1 = 1. + Card 3 +1 +Variable +SIGA +Type +F +2 +B +F +3 +4 +5 +6 +7 +8 +BETA0 +BETA1 +F +F +Card 4 for Modified Zerilli-Armstrong Constitutive Relation. This format is used +when FLAG1 = 1. + Card 4 +Variable +Type +1 +A +F +2 +N +F +3 +4 +5 +6 +7 +8 +ALPHA0 +ALPHA1 +F +F +Card 5 for Modified Johnson-Cook Fracture Criterion. This format is used when +FLAG2 = 0. + Card 5 +Variable +1 +DC +Type +F +2 +PD +F +3 +D1 +F +4 +D2 +F +5 +D3 +F +6 +D4 +F +7 +D5 +F +8 +Card 5 for Cockcroft Latham Fracture Criterion. This format is used when +FLAG2 = 1. +3 +4 +5 +6 +7 +8 + Card 5 +Variable +1 +DC +2 +WC +Type +F +Additional Element Erosion Criteria Card. + Card 6 +Variable +1 +TC +2 +3 +4 +5 +6 +7 +8 +TAUC +Type +F +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus, E. +Poisson’s ratio, 𝑣. +BETA +Damage coupling parameter; see Eq. (107.3). +EQ.0.0: No coupling between ductile damage and +the +constitutive relation. +EQ.1.0: Full coupling between ductile damage and +the +constitutive relation. +Taylor-Quinney coefficient 𝜒, see Eq. (107.20). Gives the portion +of plastic work converted into heat (normally taken to be 0.9) +Specific heat 𝐶𝑝, see Eq. (107.20) +XS1 +CP +ALPHA +Thermal expansion coefficient, 𝛼. +EPS0 +Tr +Tm +T0 +Quasi-static +EQ.(107.12).Set description under *MAT_015. +threshold +strain +rate +(𝜀̇0 = 𝑝̇0 = 𝑟 ̇0), +see +Room temperature, see Eq. (107.13) +Melt temperature, see Eq. (107.13) +Initial temperature +VARIABLE +DESCRIPTION +FLAG1 +Constitutive relation flag; see Eq. (107.11) and (107.14) +EQ.0.0: Modified Johnson-Cook constitutive relation, see Eq. +(107.11). +EQ.1.0: Zerilli-Armstrong +(107.14). +constitutive +relation, +see Eq. +FLAG2 +Fracture criterion flag; see Eq. (107.15) and (107.19). +EQ.0.0: Modified Johnson-Cook fracture criterion; see Eq. +(107.15). +EQ.1.0: Cockcroft-Latham fracture criterion; see Eq. (107.19). +K +G +A +B +N +C +M +Q1 +C1 +Q2 +C2 +Bulk modulus +Shear modulus +Johnson-Cook yield stress A, see Eq. (107.11). +Johnson-Cook hardening parameter B, see Eq. (107.11). +Johnson-Cook hardening parameter n, see Eq. (107.11). +Johnson-Cook strain rate sensitivity parameter C, see Eq. +(107.11). +Johnson-Cook thermal softening parameter m, see Eq. (107.11). +Voce hardening parameter 𝑄1 (when B = n = 0), see Eq. (107.11). +Voce hardening parameter 𝐶1 (when B = n = 0), see Eq. (107.11). +Voce hardening parameter 𝑄2 (when B = n = 0), see Eq. (107.11). +Voce hardening parameter 𝐶2 (when B = n = 0), see Eq. (107.11). +SIGA +B +BETA0 +BETA1 +Zerilli-Armstrong parameter 𝛼𝑎, see Eq. (107.14). +Zerilli-Armstrong parameter 𝐵, see Eq. (107.14). +Zerilli-Armstrong parameter 𝛽0, see Eq. (107.14). +Zerilli-Armstrong parameter 𝛽1, see Eq. (107.14). +A +Zerilli-Armstrong parameter 𝐴, see Eq. (107.14). +*MAT_MODIFIED_JOHNSON_COOK +DESCRIPTION +N +Zerilli-Armstrong parameter 𝑛, see Eq. (107.14). +ALPHA0 +Zerilli-Armstrong parameter 𝛼0, see Eq. (107.14). +ALPHA1 +Zerilli-Armstrong parameter 𝛼1, see Eq. (107.14). +DC +Critical damage parameter 𝐷𝑐, see Eq. (107.15) and (107.21). +When the damage value 𝐷 reaches this value, the element is +eroded from the calculation. +PD +Damage threshold, see Eq. (107.15). +D1-D5 +Fracture parameters in the Johnson-Cook fracture criterion, see +Eq. (107.16). +Critical Cockcroft-Latham parameter 𝑊𝑐, see Eq. (107.19). When +the plastic work per volume reaches this value, the element is +eroded from the simulation. +Critical temperature parameter 𝑇𝑐, see Eq. (107.23). When the +temperature 𝑇, reaches this value, the element is eroded from the +simulation. +Critical shear stress parameter 𝜏𝑐. When the maximum shear +stress 𝜏 reaches this value, the element is eroded from the +simulation. +WC +TC +TAUC +Remarks: +An additive decomposition of the rate-of-deformation tensor 𝐝 is assumed, i.e. +𝐝 = 𝐝𝑒 + 𝐝𝑝 + 𝐝𝑡 +(107.1) +Where 𝐝𝑒 is the elastic part, 𝐝𝑝 is the plastic part and 𝐝𝑡 is the thermal part. +The elastic rate-of-deformation 𝐝𝑒 is defined by a linear hypo-elastic relation +σ̃∇𝐽 = (𝐾 − +𝐺) tr(𝐝𝑒)𝐈 + 𝟐𝐺𝐝𝑒 +(107.2) +Where 𝐈 is the unit tensor, 𝐾 is the bulk modulus and 𝐺 is the shear modulus. The +effective stress tensor is defined by +σ̃ = +1 − 𝛽𝐷 +(107.3) +Where σ is the Cauchy-stress and 𝐷 is the damage variable, while the Jaumann rate of +the effective stress reads +σ̃∇𝐽 = σ̃̇ − 𝐖 ⋅ σ̃ − σ̃ ⋅ 𝐖𝑇 +(107.4) +Where 𝐖 is the spin tensor. The parameter 𝛽 is equal to unity for coupled damage +and equal to zero for uncoupled damage. +The thermal rate-of-deformation 𝐝𝑇 is defined by +𝐝𝑇 = 𝛼𝑇̇𝐈 +Where 𝛼 is the linear thermal expansion coefficient and 𝑇 is the temperature. +The plastic rate-of-deformation is defined by the associated flow rule as +𝐝𝑝 = 𝑟 ̇ +∂𝑓 +∂σ += +𝑟 ̇ +1 − 𝛽𝐷 +σ̃′ +𝜎̃eq +(107.5) +(107.6) +Where (⋅)′ means the deviatoric part of the tensor, 𝑟 is the damage-equivalent plastic +strain, 𝑓 is the dynamic yield function, i.e. +𝐝𝑝 = 𝑟 ̇ +∂𝑓 +∂σ += +𝑟 ̇ +1 − 𝛽𝐷 +σ̃′ +𝜎̃eq +And 𝜎̃eq is the damage-equivalent stress. +σ̃′: σ̃′ − 𝜎𝑌(𝑟, 𝑟 ̇, 𝑇) ≤ 0, +𝑓 = √ +𝑟 ̇ ≥ 0, +𝑟 ̇𝑓 = 0 +𝜎̃eq = √ +σ̃′: σ̃′ +The following plastic work conjugate pairs are identified +𝑊̇ 𝑝 = σ: 𝐝𝑝 = 𝜎̃eq𝑟 ̇ = 𝜎eq𝑝̇ +(107.6) +(107.7) +(107.8) +(107.9) +Where 𝑊̇ 𝑝 is the specific plastic work rate, and the equivalent stress 𝜎eq and the +equivalent plastic strain 𝑝 are defined as +𝜎eq = √ +σ̃′: σ̃′ = (1 − 𝛽𝐷)𝜎̃eq 𝑝̇ = √ +𝐝𝑝: 𝐝𝑝 = +𝑟 ̇ +(1 − 𝛽𝐷) +(107.10) +The material strength 𝜎𝑌 is defined by: +1. The modified Johnson-Cook constitutive relation +𝜎𝑌 = {𝐴 + 𝐵𝑟𝑛 + ∑ 𝑄𝑖[1 − exp(−𝐶𝑖𝑟)] +𝑖=1 +} (1 + 𝑟 ̇∗)𝐶(1 − 𝑇∗𝑚) +(107.11) +Where 𝐴, 𝐵, 𝐶, 𝑚, 𝑛, 𝑄1, 𝐶1, 𝑄2, 𝐶2 are material parameters; the normalized dam- +age-equivalent plastic strain rate 𝑟 ̇∗ is defined by +𝑟 ̇∗ = +𝑟 ̇ +𝜀̇0 +(107.12) +In which 𝜀̇0 is a user-defined reference strain rate; and the homologous temper- +ature reads +𝑇∗ = +𝑇 − 𝑇𝑟 +𝑇𝑚 − 𝑇𝑟 +(107.13) +In which 𝑇𝑟 is the room temperature and 𝑇𝑚 is the melting temperature. +2. The Zerilli-Armstrong constitutive relation +𝜎𝑌 = {𝜎𝑎 + 𝐵exp[−(𝛽0 − 𝛽1ln𝑟 ̇)𝑇] + 𝐴𝑟𝑛exp[−(𝛼0 − 𝛼1ln𝑟 ̇)𝑇]} +(107.14) +Where 𝜎𝑎, 𝐵, 𝛽0, 𝛽1, 𝐴, 𝑛, 𝛼0, 𝛼1 are material parameters. +Damage evolution is defined by: +1. The extended Johnson-Cook damage evolution rule: +𝐷̇ = +𝐷𝑐 +𝑝𝑓 − 𝑝𝑑 +⎧ +{ +⎨ +{ +⎩ +𝑝 ≤ 𝑝𝑑 +𝑝 > 𝑝𝑑 +(107.15) +Where the current equivalent fracture strain 𝑝𝑓 = 𝑝𝑓 (𝜎 ∗, 𝑝̇∗, 𝑇∗) is defined as +𝑝𝑓 = [𝐷1 + 𝐷2exp(𝐷3𝜎 ∗)](1 + 𝑝̇∗)𝐷4(1 + 𝐷5𝑇∗) +(107.16) +and 𝐷1, 𝐷2, 𝐷3, 𝐷4, 𝐷5, 𝐷𝐶, 𝑝𝑑 are material parameters; the normalized +equivalent plastic strain rate 𝑝̇∗ is defined by +𝑝̇∗ = +𝑝̇ +𝜀̇0 +and the stress triaxiality 𝜎 ∗ reads +𝜎 ∗ = +𝜎𝐻 +𝜎eq +, +𝜎𝐻 = +𝑡𝑟(σ) +2.The Cockcroft-Latham damage evolution rule: +𝐷̇ = +𝐷𝐶 +𝑊𝐶 +max(𝜎1, 0)𝑝̇ +where 𝐷𝐶, 𝑊𝐶 are material parameters. +(107.17) +(107.18) +(107.19) +Adiabatic heating is calculated as +𝑇̇ = 𝜒 +𝛔: 𝐝𝑝 +𝜌𝐶𝑝 += 𝜒 +𝜎̃𝑒𝑞𝑟 ̇ +𝜌𝐶𝑝 +(107.20) +Where 𝜒 is the Taylor-Quinney parameter, 𝜌 is the density and 𝐶𝑝 is the specific heat. +The initial value of the temperature 𝑇0 may be specified by the user. +Element erosion occurs when one of the following several criteria are fulfilled: +1. The damage is greater than the critical value +𝐷 ≥ 𝐷𝐶 +(107.21) +2. The maximum shear stress is greater than a critical value +𝜏max = +max{|𝜎1 − 𝜎2|, ∣𝜎2 − 𝜎3∣, ∣𝜎3 − 𝜎1∣} ≥ 𝜏𝐶 +(107.22) +3. The temperature is greater than a critical value +𝑇 ≥ 𝑇𝐶 +(107.23) +History Variable +Description +1 +2 +3 +4 +5 +8 +9 +Evaluation of damage D +Evaluation of stress triaxiality 𝜎 ∗ +Evaluation of damaged plastic strain r +Evaluation of temperature T +Evaluation of damaged plastic strain rate 𝑟 ̇ +Evaluation of plastic work per volume W +Evaluation of maximum shear stress 𝜏max +*MAT_ORTHO_ELASTIC_PLASTIC +This is Material Type 108. This model combines orthotropic elastic plastic behavior +with an anisotropic yield criterion. This model is implemented only for shell elements. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F + Card 2 +1 +Variable +SIGMA0 +Type +F + Card 3 +1 +2 +LC +I +2 +3 +4 +5 +6 +7 +8 +E11 +E22 +G12 +PR12 +PR23 +PR31 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +QR1 +CR1 +QR2 +CR2 +F +3 +F +4 +F +5 +F +6 +7 +8 +Variable +R11 +R22 +R33 +R12 +Type +F + Card 4 +1 +F +2 +Variable +AOPT +BETA +Type +F +F + Card 5 +Variable +1 +XP +Type +F +2 +YP +F +F +3 +3 +ZP +F +F +4 +4 +A1 +F +5 +6 +7 +8 +7 +8 +5 +A2 +F +6 +A3 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D17 +F +5 +D2 +F +6 +D3 +F + VARIABLE +DESCRIPTION +*MAT_108 +7 +8 +MID +RO +E11 +E22 +G12 +PR12 +PR23 +PR31 +LC +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass Density +Young’s Modulus in 11-direction +Young’s Modulus in 22-direction +Shear modulus in 12-direction +Poisson’s ratio 12 +Poisson’s ratio 23 +Poisson’s ratio 31 +Load curve ID. This curve defines effective stress versus effective +plastic strain. QR1, CR1, QR2, and CR2 are ignored if LC is +defined. +SIGMA0 +Initial yield stress, 𝜎0 +QR1 +CR1 +QR2 +CR2 +R11 +R22 +R33 +R12 +Isotropic hardening parameter, 𝑄𝑅1 +Isotropic hardening parameter, 𝐶𝑅1 +Isotropic hardening parameter, 𝑄𝑅2 +Isotropic hardening parameter, 𝐶𝑅2 +Yield criteria parameter, 𝑅11 +Yield criteria parameter, 𝑅22 +Yield criteria parameter, 𝑅33 +Yield criteria parameter, 𝑅12 +AOPT +*MAT_ORTHO_ELASTIC_PLASTIC +DESCRIPTION +Material axes option +EQ.0.0: Locally orthotropic with material axes determined by +element nodes as shown in Figure M2-1. Nodes 1, 2 +and 4 of an element are identical to the node used for +the definition of a coordinate system as by *DEFINE_- +COORDINATE_NODES, and then rotated about the +shell element normal by an angle BETA. +EQ.2.0: Globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: Locally orthotropic material axes determined by +offsetting the material axes by an angle, BETA, from a +line determined by taking the cross product of the vec- +tor v with the normal to the plane of the element. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +BETA +Material angle in degrees for AOPT = 0 and 3. BETA may be +overridden on the element card, see *ELEMENT_SHELL_BETA. +XP YP ZP +Coordinates of point 𝐩 for AOPT = 1. +A1 A2 A3 +Components of vector 𝐚 for AOPT = 2. +V1 V2 V3 +Components of vector 𝐯 for AOPT = 3. +D1 D2 D3 +Components of vector 𝐝 for AOPT = 2. +Remarks: +The yield function is defined as +where the equivalent stress 𝜎eq is defined as an anisotropic yield criterion +𝑓 = 𝑓 ̅(σ) − [𝜎0 + 𝑅(𝜀𝑝)] +𝜎eq = √𝐹(𝜎22 − 𝜎33)2 + 𝐺(𝜎33 − 𝜎11)2 + 𝐻(𝜎11 − 𝜎22)2 + 2𝐿𝜎23 +2 + 2𝑀𝜎31 +2 +2 + 2𝑁𝜎12 +Where F, G, H, L, M and N are constants obtained by test of the material in different +orientations. They are defined as +𝐹 = +𝐺 = +𝐻 = +𝐿 = +𝑀 = +𝑁 = +( +( +( +2 + +𝑅22 +2 + +𝑅33 +2 + +𝑅11 +2 − +𝑅33 +2 − +𝑅11 +2 − +𝑅22 +2 ) +𝑅11 +2 ) +𝑅22 +2 ) +𝑅33 +2 +2𝑅23 +2 +2𝑅31 +2 +2𝑅12 +The yield stress ratios are defined as follows +𝑅11 = +𝑅22 = +𝑅33 = +𝑅12 = +𝑅23 = +𝑅31 = +𝜎̅̅̅̅̅11 +𝜎0 +𝜎̅̅̅̅̅22 +𝜎0 +𝜎̅̅̅̅̅33 +𝜎0 +𝜎̅̅̅̅̅12 +𝜏0 +𝜎̅̅̅̅̅23 +𝜏0 +𝜎̅̅̅̅̅31 +𝜏0 +where 𝜎𝑖𝑗 is the measured yield stress values, 𝜎0 is the reference yield stress and +𝜏0 = 𝜎0/√3. +The strain hardening is either defined by the load curve or the strain hardening R is +defined by the extended Voce law, +𝑅(𝜀𝑝) = ∑ 𝑄𝑅𝑖[1 − exp(−𝐶𝑅𝑖𝜀𝑝)] +𝑖=1 +where 𝜀𝑝 is the effective (or accumulated) plastic strain, and 𝑄𝑅𝑖 and 𝐶𝑅𝑖 are strain +hardening parameters. +*MAT_JOHNSON_HOLMQUIST_CERAMICS +This is Material Type 110. This Johnson-Holmquist Plasticity Damage Model is useful +for modeling ceramics, glass and other brittle materials. A more detailed description +can be found in a paper by Johnson and Holmquist [1993]. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +Variable +EPSI +Type +F + Card 3 +Variable +1 +D1 +Type +F + VARIABLE +MID +2 +RO +F +2 +T +F +2 +D2 +F +3 +G +F +3 +4 +A +F +4 +5 +B +F +5 +6 +C +F +6 +7 +M +F +7 +8 +N +F +8 +SFMAX +HEL +PHEL +BETA +F +F +F +F +3 +K1 +F +4 +K2 +F +5 +K3 +F +6 +FS +F +DESCRIPTION +7 +8 +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Density +G +A +B +C +M +Shear modulus +Intact normalized strength parameter +Fractured normalized strength parameter +Strength parameter (for strain rate dependence) +Fractured strength parameter (pressure exponent) +VARIABLE +DESCRIPTION +N +EPS0 +T +SFMAX +HEL +PHEL +BETA +D1 +D2 +K1 +K2 +K3 +FS +Intact strength parameter (pressure exponent). +Quasi-static threshold strain rate. See *MAT_015. +Maximum tensile pressure strength. +Maximum normalized fractured strength (defaults to 1020 when +set to 0.0). +Hugoniot elastic limit. +Pressure component at the Hugoniot elastic limit. +Fraction of elastic energy loss converted to hydrostatic energy +(affects bulking pressure (history variable 1) that accompanies +damage). +Parameter for plastic strain to fracture. +Parameter for plastic strain to fracture (exponent). +First pressure coefficient (equivalent to the bulk modulus). +Second pressure coefficient. +Third pressure coefficient. +Element deletion criterion. +FS.LT.0: fail if 𝑝∗ + 𝑡∗ < 0 (tensile failure). +FS.EQ.0: no failure (default). +FS.GT.0: fail if the effective plastic strain > FS. +Remarks: +The equivalent stress for a ceramic-type material is given by +𝜎 ∗ = 𝜎𝑖 +∗ − 𝐷(𝜎𝑖 +∗ − 𝜎𝑓 +∗) +where +∗ = 𝑎(𝑝∗ + 𝑡∗)𝑛(1 + 𝑐ln𝜀̇∗) +𝜎𝑖 +represents the intact, undamaged behavior. The superscript, '*', indicates a normalized +quantity. The stresses are normalized by the equivalent stress at the Hugoniot elastic +limit, the pressures are normalized by the pressure at the Hugoniot elastic limit, and the +strain rate by the reference strain rate defined in the input. In this equation 𝑎 is the +intact normalized strength parameter, 𝑐 is the strength parameter for strain rate +dependence, 𝜀̇∗ is the normalized plastic strain rate, and, +𝑡∗ = +𝑝∗ = +PHEL +PHEL +, +, +where 𝑇 is the maximum tensile pressure strength, PHEL is the pressure component at +the Hugoniot elastic limit, and p is the pressure. +𝐷 = ∑ +Δ𝜀𝑝 +𝑝 +𝜀𝑓 +represents the accumulated damage (history variable 2) based upon the increase in +plastic strain per computational cycle and the plastic strain to fracture +and +𝑝 = 𝑑1(𝑝∗ + 𝑡∗)𝑑2 +𝜀𝑓 +∗ = 𝑏(𝑝∗)𝑚(1 + 𝑐 ln𝜀̇) ≤ SFMAX +𝜎𝑓 +represents the damaged behavior. The parameter d1 controls the rate at which damage +accumulates. If it is made 0, full damage occurs in one time step i.e. instantaneously. It +is also the best parameter to vary if one attempts to reproduce results generated by +another finite element program. +In undamaged material, the hydrostatic pressure is given by +in compression and +𝑃 = 𝑘1𝜇 + 𝑘2𝜇2 + 𝑘3𝜇3 +𝑃 = 𝑘1𝜇 +⁄ +in tension where 𝜇 = 𝜌 𝜌0 − 1 +. When damage starts to occur, there is an increase in +pressure. A fraction, between 0 and 1, of the elastic energy loss, 𝛽, is converted into +hydrostatic potential energy (pressure). The details of this pressure increase are given +in the reference. +Given HEL and G, 𝜇hel can be found iteratively from +2 + 𝑘3𝜇hel +and, subsequently, for normalization purposes, +HEL = 𝑘1𝜇hel + 𝑘2𝜇hel +3 + (4 3⁄ )𝑔(𝜇hel/(1 + 𝜇hel) +2-576 (EOS) +LS-DYNA R10.0 +𝑃hel = 𝑘1𝜇hel + 𝑘2𝜇hel +and +These are calculated automatically by LS-DYNA if 𝜌𝑓0 is zero on input. +𝜎hel = 1.5(hel − 𝑝hel) +*MAT_JOHNSON_HOLMQUIST_CONCRETE +This is Material Type 111. This model can be used for concrete subjected to large +strains, high strain rates and high pressures. The equivalent strength is expressed as a +function of the pressure, strain rate, and damage. The pressure is expressed as a +function of the volumetric strain and includes the effect of permanent crushing. The +damage is accumulated as a function of the plastic volumetric strain, equivalent plastic +strain and pressure. A more detailed description of this model can be found in the +paper by Holmquist, Johnson, and Cook [1993]. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +Variable +Type + Card 3 +Variable +1 +T +F +1 +D1 +Type +F + VARIABLE +MID +2 +RO +F +2 +3 +G +F +3 +4 +A +F +4 +EPS0 +EFMIN +SFMAX +F +F +F +2 +D2 +F +3 +K1 +F +4 +K2 +F +5 +B +F +5 +PC +F +5 +K3 +F +6 +C +F +6 +UC +F +6 +FS +F +7 +N +F +7 +PL +F +7 +8 +FC +F +8 +UL +F +8 +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +G +A +B +Shear modulus. +Normalized cohesive strength. +Normalized pressure hardening. +VARIABLE +DESCRIPTION +C +N +FC +T +Strain rate coefficient. +Pressure hardening exponent. +Quasi-static uniaxial compressive strength. +Maximum tensile hydrostatic pressure. +EPS0 +Quasi-static threshold strain rate. See *MAT_015. +EFMIN +Amount of plastic strain before fracture. +SFMAX +Normalized maximum strength. +PC +UC +PL +UL +D1 +D2 +K1 +K2 +K3 +FS +Crushing pressure. +Crushing volumetric strain. +Locking pressure. +Locking volumetric strain. +Damage constant. +Damage constant. +Pressure constant. +Pressure constant. +Pressure constant. +Failure type: +FS.LT.0: fail if damage strength < 0 +FS.EQ.0: fail if 𝑃∗ + 𝑇∗ ≤ 0 (tensile failure). +FS.GT.0: fail if the effective plastic strain > FS. +Remarks: +The normalized equivalent stress is defined as +𝑓′𝑐 +𝜎 ∗ = +where 𝜎 is the actual equivalent stress, and 𝑓′ is the quasi-static uniaxial compressive +strength. The expression is defined as: +𝜎 ∗ = [𝐴(1 − 𝐷) + 𝐵𝑃∗𝑁][1 + 𝐶ln(𝜀̇∗)] +where 𝐷 is the damage parameter, 𝑃∗ = 𝑃 𝑓′𝑐⁄ is the normalized pressure and 𝜀̇∗ = 𝜀̇ 𝜀̇0⁄ +is the dimensionless strain rate. The model incrementally accumulates damage, D, both +from equivalent plastic strain and plastic volumetric strain, and is expressed as +𝐷 = ∑ +Δ𝜀𝑝 + Δ𝜇𝑝 +𝐷1(𝑃∗ + 𝑇∗)𝐷2 +where Δ𝜀𝑝 and Δ𝜇𝑝 are the equivalent plastic strain and plastic volumetric strain, 𝐷1and +𝐷2 are material constants and 𝑇∗ = 𝑇 𝑓c +′⁄ is the normalized maximum tensile hydrostatic +pressure. +The damage strength, DS, is defined in compression when 𝑃∗ > 0 as +DS = 𝑓𝑐 +′ min[SFMAX, 𝐴(1 − 𝐷) + 𝐵𝑃∗𝑁 +] [1 + 𝐶 ∗ ln(𝜀̇∗)] +or in tension if 𝑃∗ < 0, as +DS = 𝑓𝑐 +′ max [0, 𝐴(1 − 𝐷) − 𝐴 ( +)] [1 + 𝐶 ∗ ln(𝜀̇∗)] +𝑃∗ +The pressure for fully dense material is expressed as +𝑃 = 𝐾1𝜇̅̅̅̅ + 𝐾2𝜇̅̅̅̅2 + 𝐾3𝜇̅̅̅̅3 +where 𝐾1 , 𝐾2 and 𝐾3 are material constants and the modified volumetric strain is +defined as +where 𝜇lock is the locking volumetric strain. +𝜇̅̅̅̅ = +𝜇 − 𝜇lock +1 + 𝜇lock +*MAT_FINITE_ELASTIC_STRAIN_PLASTICITY +This is Material Type 112. An elasto-plastic material with an arbitrary stress versus +strain curve and arbitrary strain rate dependency can be defined. The elastic response +of this model uses a finite strain formulation so that large elastic strains can develop +before yielding occurs. This model is available for solid elements only. See Remarks +below. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +6 +7 +8 +SIGY +ETAN +F +F +Default +none +none +none +none +none +0.0 + Card 2 +Variable +Type +Default +1 +C +F +0 + Card 3 +1 +2 +P +F +0 +2 +3 +4 +5 +6 +7 +8 +LCSS +LCSR +F +0 +3 +F +0 +4 +5 +6 +7 +8 +Variable +EPS1 +EPS2 +EPS3 +EPS4 +EPS5 +EPS6 +EPS7 +EPS8 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ES1 +ES2 +ES3 +ES4 +ES5 +ES6 +ES7 +ES8 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +SIGY +ETAN +C +P +LCSS +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +Yield stress. +Tangent modulus, ignored if (LCSS.GT.0) is defined. +Strain rate parameter, C, see formula below. +Strain rate parameter, P, see formula below. +Load curve ID or Table ID. Load curve ID defining effective +stress versus effective plastic strain. If defined EPS1 - EPS8 and +ES1 - ES8 are ignored. The table ID defines for each strain rate +value a load curve ID giving the stress versus effective plastic +strain for that rate, See Figure M24-1. The stress versus effective +plastic strain curve for the lowest value of strain rate is used if the +strain rate falls below the minimum value. Likewise, the stress +versus effective plastic strain curve for the highest value of strain +rate is used if the strain rate exceeds the maximum value. The +strain rate parameters: C and P; the curve ID, LCSR; EPS1 - EPS8 +and ES1 - ES8 are ignored if a Table ID is defined. +LCSR +Load curve ID defining strain rate scaling effect on yield stress. +VARIABLE +EPS1 - EPS8 +DESCRIPTION +Effective plastic strain values (optional if SIGY is defined). At +least 2 points should be defined. The first point must be zero +corresponding to the initial yield stress. WARNING: If the first +point is nonzero the yield stress is extrapolated to determine the +initial yield. If this option is used SIGY and ETAN are ignored +and may be input as zero. +ES1 - ES8 +Corresponding yield stress values to EPS1 - EPS8. +Remarks: +The stress strain behavior may be treated by a bilinear stress strain curve by defining +the tangent modulus, ETAN. Alternately, a curve similar to that shown in Figure M10-1 +is expected to be defined by (EPS1,ES1) - (EPS8,ES8); however, an effective stress versus +effective plastic strain curve (LCSS) may be input instead if eight points are insufficient. +The cost is roughly the same for either approach. The most general approach is to use +the table definition (LCSS) discussed below. +Three options to account for strain rate effects are possible. +1. Strain rate may be accounted for using the Cowper and Symonds model which +scales the yield stress with the factor +1 + ( +𝑝⁄ +) +𝜀̇ +where 𝜀̇ is the strain rate, 𝜀̇ = √𝜀̇𝑖𝑗𝜀̇𝑖𝑗. +2. For complete generality a load curve (LCSR) to scale the yield stress may be +input instead. In this curve the scale factor versus strain rate is defined. +3. +If different stress versus strain curves can be provided for various strain rates, +the option using the reference to a table (LCSS) can be used. Then the table +input in *DEFINE_TABLE has to be used, see Figure M24-1. +*MAT_TRIP +This is Material Type 113. This isotropic elasto-plastic material model applies to shell +elements only. It features a special hardening law aimed at modelling the temperature +dependent hardening behavior of austenitic stainless TRIP-steels. TRIP stands for +Transformation Induced Plasticity. A detailed description of this material model can be +found in Hänsel, Hora, and Reissner [1998] and Schedin, Prentzas, and Hilding [2004]. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +Default + Card 2 +Variable +Type +Default +1 +A +F +2 +B +F + Card 3 +1 +2 +Variable +AHS +BHS +3 +E +F +3 +C +3 +M +4 +PR +5 +CP +6 +T0 +7 +8 +TREF +TA0 +4 +D +4 +N +5 +P +6 +Q +7 +8 +E0MART +VM0 +5 +6 +EPS0 +HMART +7 +K1 +8 +K2 +Type +Default + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +E +PR +CP +T0 +TREF +TA0 +A +B +C +D +P +Q +*MAT_113 +DESCRIPTION +Young’s modulus. +Poisson’s ratio. +Adiabatic temperature calculation option: +EQ.0.0: Adiabatic temperature calculation is disabled. +GT.0.0: CP is the specific heat Cp. Adiabatic temperature +calculation is enabled. +Initial temperature T0 of the material if adiabatic temperature +calculation is enabled. +Reference temperature for output of the yield stress as history +variable 1. +Reference temperature TA0, the absolute zero for the used +temperature scale, e.g. -273.15 if the Celsius scale is used and 0.0 +if the Kelvin scale is used. +Martensite rate equation parameter A, see equations below. +Martensite rate equation parameter B, see equations below. +Martensite rate equation parameter C, see equations below. +Martensite rate equation parameter D, see equations below. +Martensite rate equation parameter p, see equations below. +Martensite rate equation parameter Q, see equations below. +E0MART +Martensite rate equation parameter E0(mart) , see equations below. +VM0 +The initial volume fraction of martensite 0.0 < Vm0 < 1.0 may be +initialised using two different methods: +GT.0.0: Vm0 is set to VM0. +LT.0.0: Can be used only when there are initial plastic strains +εp present, e.g. + when using *INITIAL_STRESS_- +SHELL. The absolute value of VM0 is then the load +curve ID for a function f that sets 𝑉𝑚0 = 𝑓 (𝜀𝑝). The +function f must be a monotonically nondecreasing +function of 𝜀𝑝. +DESCRIPTION +*MAT_TRIP +AHS +BHS +M +N +Hardening law parameter AHS, see equations below. +Hardening law parameter BHS, see equations below. +Hardening law parameter m, see equations below. +Hardening law parameter n, see equations below. +EPS0 +Hardening law parameter ε0, see equations below. +HMART +Hardening law parameter ΔHγ→α’ , see equations below. +Hardening law parameter K1, see equations below. +Hardening law parameter K2, see equations below. +K1 +K2 +Remarks: +Here a short description is given of the TRIP-material model. The material model uses +the von Mises yield surface in combination with isotropic hardening. The hardening is +temperature dependent and therefore this material model must be run either in a +coupled thermo-mechanical solution, using prescribed temperatures or using the +adiabatic temperature calculation option. Setting the parameter CP to the specific heat +Cp of the material activates the adiabatic temperature calculation that calculates the +temperature rate from the equation +𝜎𝑖𝑗𝐷𝑖𝑗 +𝜌𝐶𝑝 +, +𝑇̇ = ∑ +𝑖,𝑗 +where 𝛔: 𝐃𝑝 (the numerator) is the plastically dissipated heat. Using the Kelvin scale is +recommended, even though other scales may be used without problems. +The hardening behavior is described by the following equations. The Martensite rate +equation is +∂𝑉𝑚 +∂𝜀̅𝑝 = +⎧0 +{{ +⎨ +{{ +⎩ +𝑝 ( +𝑉𝑚 +1 − 𝑉𝑚 +𝑉𝑚 +where +) +𝐵+1 +𝐵 [1 − tanh(C + D × 𝑇)] +𝜀 < 𝐸0(mart) +exp ( +𝑇 − 𝑇𝐴0 +) 𝜀̅𝑝 ≥ 𝐸0(mart) +𝜀̅𝑝 = effective plastic strain and +𝑇 = temperature. +The martensite fraction is integrated from the above rate equation: +𝑉𝑚 = ∫ +∂𝑉𝑚 +∂𝜀̅𝑝 +𝑑𝜀̅𝑝. +It always holds that 0.0 < Vm < 1.0. The initial martensite content is Vm0 and must be +greater than zero and less than 1.0. Note that Vm0 is not used during a restart or when +initializing the Vm history variable using *INITIAL_STRESS_SHELL. +The yield stress σy is +𝜎𝑦 = {𝐵𝐻𝑆 − (𝐵𝐻𝑆 − 𝐴𝐻𝑆)exp(−𝑚[𝜀̅𝑝 + 𝜀0]𝑛)}(𝐾1 + 𝐾2𝑇) + Δ𝐻𝛾→𝛼′𝑉𝑚. +The parameters p and B should fulfill the following condition +1 + 𝐵 +< 𝑝 +if not fulfilled then the martensite rate will approach infinity as 𝑉𝑚 approaches zero. +Setting the parameter 𝜀0 larger than zero, typical range 0.001-0.02 is recommended. A +part from the effective true strain a few additional history variables are output, see +below. +History variables that are output for post-processing: +Variable +Description +1 +2 +3 +Yield stress of material at temperature TREF. Useful to evaluate the +strength of the material after e.g., a simulated forming operation. +Volume fraction martensite, Vm +CP.EQ.0.0: Not used +CP.GT.0.0: Temperature from adiabatic temperature calculation +*MAT_LAYERED_LINEAR_PLASTICITY +This is Material Type 114. A layered elastoplastic material with an arbitrary stress +versus strain curve and an arbitrary strain rate dependency can be defined. This +material must be used with the user defined integration rules, see *INTEGRATION- +SHELL, for modeling laminated composite and sandwich shells where each layer can be +represented by elastoplastic behavior with constitutive constants that vary from layer to +layer. Lamination theory is applied to correct for the assumption of a uniform constant +shear strain through the thickness of the shell. Unless this correction is applied, the +stiffness of the shell can be grossly incorrect leading to poor results. Generally, without +the correction the results are too stiff. This model is available for shell elements only. +Also, see Remarks below. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +6 +7 +8 +SIGY +ETAN +FAIL +TDEL +F +F +F +Default +none +none +none +none +none +0.0 +10.E+20 + Card 2 +Variable +Type +Default +1 +C +F +0 + Card 3 +1 +2 +P +F +0 +2 +3 +4 +5 +6 +7 +LCSS +LCSR +F +0 +3 +F +0 +4 +5 +6 +7 +8 +Variable +EPS1 +EPS2 +EPS3 +EPS4 +EPS5 +EPS6 +EPS7 +EPS8 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +2-588 (EOS) +LS-DYNA R10.0 +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ES1 +ES2 +ES3 +ES4 +ES5 +ES6 +ES7 +ES8 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +SIGY +ETAN +FAIL +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +Yield stress. +Tangent modulus, ignored if (LCSS.GT.0) is defined. +Failure flag. +LT.0.0: User defined failure subroutine, matusr_24 in dyn21.F, +is called to determine failure +EQ.0.0: Failure is not considered. This option is recommended +if failure is not of interest since many calculations will +be saved. +GT.0.0: Plastic strain to failure. When the plastic strain reaches +this value, the element is deleted from the calculation. +TDEL +Minimum time step size for automatic element deletion. +C +P +Strain rate parameter, C, see formula below. +Strain rate parameter, P, see formula below. +LCSS +*MAT_LAYERED_LINEAR_PLASTICITY +DESCRIPTION +Load curve ID or Table ID. Load curve ID defining effective +stress versus effective plastic strain. If defined EPS1 - EPS8 and +ES1 - ES8 are ignored. The table ID defines for each strain rate +value a load curve ID giving the stress versus effective plastic +strain for that rate, See Figure M24-1. The stress versus effective +plastic strain curve for the lowest value of strain rate is used if the +strain rate falls below the minimum value. Likewise, the stress +versus effective plastic strain curve for the +highest value of strain rate is used if the strain rate exceeds the +maximum value. The strain rate parameters: C and P; the curve +ID, LCSR; EPS1 - EPS8 and ES1 - ES8 are ignored if a Table ID is +defined. +LCSR +Load curve ID defining strain rate scaling effect on yield stress. +EPS1 - EPS8 +Effective plastic strain values (optional if SIGY is defined). At +least 2 points should be defined. The first point must be zero +corresponding to the initial yield stress. WARNING: If the first +point is nonzero the yield stress is extrapolated to determine the +initial yield. If this option is used SIGY and ETAN are ignored +and may be input as zero. +ES1 - ES8 +Corresponding yield stress values to EPS1 - EPS8. +Remarks: +The stress strain behavior may be treated by a bilinear stress strain curve by defining +the tangent modulus, ETAN. Alternately, a curve similar to that shown in Figure M10-1 +is expected to be defined by (EPS1, ES1) - (EPS8, ES8); however, an effective stress +versus effective plastic strain curve (LCSS) may be input instead if eight points are +insufficient. The cost is roughly the same for either approach. The most general +approach is to use the table definition (LCSS) discussed below. +Three options to account for strain rate effects are possible. +1. Strain rate may be accounted for using the Cowper and Symonds model which +scales the yield stress with the factor +1 + ( +𝑝⁄ +) +𝜀̇ +where 𝜀̇ is the strain rate, 𝜀̇ = √𝜀̇𝑖𝑗𝜀̇𝑖𝑗. +2. For complete generality a load curve (LCSR) to scale the yield stress may be +input instead. In this curve the scale factor versus strain rate is defined. +3. +If different stress versus strain curves can be provided for various strain rates, +the option using the reference to a table (LCSS) can be used. Then the table +input in *DEFINE_TABLE has to be used, see Figure M24-1. +*MAT_UNIFIED_CREEP +This is Material Type 115. This is an elastic creep model for modeling creep behavior +when plastic behavior is not considered. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +A +F +6 +N +F +7 +M +F +8 +Default +none +none +none +none +none +none +none + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +E +PR +A +N +M +Mass density. +Young’s modulus. +Poisson’s ratio. +Stress coefficient. +Stress exponent. +Time exponent. +Remarks: +The effective creep strain, 𝜀̅𝑐, given as: +𝜀̅𝑐 = 𝐴𝜎̅̅̅̅̅ 𝑛𝑡 ̅𝑚 +where A, n, and m are constants and 𝑡 ̅ is the effective time. The effective stress, 𝜎̅̅̅̅̅, is +defined as: +𝜎̅̅̅̅̅ = √ +𝜎𝑖𝑗𝜎𝑖𝑗 +The creep strain, therefore, is only a function of the deviatoric stresses. The volumetric +behavior for this material is assumed to be elastic. By varying the time constant m +primary creep (m < 1), secondary creep (m = 1), and tertiary creep (m > 1) can be +modeled. This model is described by Whirley and Henshall [1992]. +*MAT_UNIFIED_CREEP +This is Material Type 115_O. This is an orthotropic elastic creep model for modeling +creep behavior when plastic behavior is not considered. This material is only available +for solid elements, and is available for both explicit and implicit dynamics. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E1 +F +4 +E2 +F +5 +E3 +F +6 +7 +8 +PR21 +PR31 +PR32 +F +F +F +Default +none +none +none +none +none +none +none +none + Card 2 +1 +2 +3 +Variable +G12 +G23 +G13 +Type +F +F +F +4 +A +F +5 +N +F +6 +M +F +7 +8 +Default +none +none +none +none +none +none + Card 3 +1 +2 +Variable +AOPT +MACF +Type +F +F +3 +XP +F +4 +YP +F +5 +ZP +F +6 +A1 +F +7 +A2 +F +8 +A3 +F +Default +none +none +none +none +none +none +none +none +Card 4 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +Default +none +none +none +none +none +none + VARIABLE +DESCRIPTION +MID +RO +Ei +PRij +Gij +A +N +M +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s moduli. +Elastic Poisson’s ratios. +Elastic shear moduli. +Stress coefficient. +Stress exponent. +Time exponent. +AOPT +*MAT_UNIFIED_CREEP +DESCRIPTION +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the a-direction. This option is for solid +elements only. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector v, and +an originating point, p, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +MACF +Material axes change flag for brick elements: +EQ.1: No change, default, +EQ.2: switch material axes a and b, +EQ.3: switch material axes a and c, +EQ.4: switch material axes b and c. +XP, YP, ZP +Define coordinates of point p for AOPT = 1 and 4. +A1, A2, A3 +Define components of vector a for AOPT = 2. +V1, V2, V3 +Define components of vector v for AOPT = 3 and 4. +VARIABLE +DESCRIPTION +D1, D2, D3 +Define components of vector d for AOPT = 2. +BETA +Material angle in degrees for AOPT = 3, may be overridden on +the element card, see *ELEMENT_SHELL_BETA or *ELEMENT_- +SOLID_ORTHO. +Remarks: +The stress-strain relationship is based on an additive split of the strain, +Here, the multiaxial creep strain is given by +𝜺̇ = 𝜺̇𝑒 + 𝜺̇𝑐. +and 𝜀̅𝑐 is the effective creep strain, 𝒔 the deviatoric stress +𝜺̇𝑐 = 𝜀̅𝑐̇ +2𝒔 +3𝜎̅̅̅̅̅ +, +and 𝜎̅̅̅̅̅ the effective stress +𝒔 = 𝝈 − +tr(𝝈)𝑰. +𝜎̅̅̅̅̅ = √ +𝒔: 𝒔. +The effective creep strain is given by +where A, N, and M are constants. +The stress increment is given by +𝜀̅𝑐̇ = 𝐴𝜎̅̅̅̅̅ 𝑁𝑡𝑀, +∆𝝈 = 𝑪∆𝜺𝑒 = 𝑪(∆𝜺 − ∆𝜺𝑐), +where the constitutive matrix 𝑪 is taken as orthotropic and can be represented in Voigt +notation by its inverse as +𝑪−1 = +𝐸1 +𝜐12 +𝐸1 +𝜐13 +𝐸1 +− +− +𝜐21 +𝐸2 +𝐸2 +𝜐23 +𝐸2 +− +− +𝜐31 +𝐸3 +𝜐32 +𝐸3 +𝐸3 +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +. +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +𝐺13⎦ +𝐺12 +𝐺23 +− +− +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +*MAT_116 +This is Material Type 116. This material is for modeling the elastic responses of +composite layups that have an arbitrary number of layers through the shell thickness. +A pre-integration is used to compute the extensional, bending, and coupling stiffness +for use with the Belytschko-Tsay resultant shell formulation. The angles of the local +material axes are specified from layer to layer in the *SECTION_SHELL input. This +material model must be used with the user defined integration rule for shells, see *IN- +TEGRATION_SHELL, which allows the elastic constants to change from integration +point to integration point. Since the stresses are not computed in the resultant +formulation, the stresses output to the binary databases for the resultant elements are +zero. Note that this shell does not use laminated shell theory and that storage is allocated +for just one integration point (as reported in D3HSP) regardless of the layers defined in +the integration rule. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +EA +F +3 +4 +EB +F +4 +Variable +GAB +GBC +GCA +AOPT +Type +F +F +F +F + Card 3 +Variable +1 +XP +Type +F + Card 4 +Variable +1 +V1 +Type +F +LS-DYNA R10.0 +2 +YP +F +2 +V2 +F +3 +ZP +F +3 +V3 +F +4 +A1 +F +4 +D1 +F +5 +EC +F +5 +5 +A2 +F +5 +D2 +F +6 +7 +8 +PRBA +PRCA +PRCB +F +6 +6 +A3 +F +6 +D3 +F +F +7 +F +8 +7 +8 +7 +8 +BETA +VARIABLE +DESCRIPTION +MID +RO +EA +EB +EC +PRBA +PRCA +PRCB +GAB +GBC +GCA +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Ea, Young’s modulus in a-direction. +Eb, Young’s modulus in b-direction. +Ec, Young’s modulus in c-direction. +ba, Poisson’s ratio ba. +ca, Poisson’s ratio ca. +cb, Poisson’s ratio cb. +Gab, shear modulus ab. +Gbc, shear modulus bc. +Gca, shear modulus ca. +VARIABLE +DESCRIPTION +AOPT +Material axes option, see Figure M2-1: +EQ.0.0: locally orthotropic with material axes determined by +element nodes as shown in Figure M2-1. Nodes 1, 2, +and 4 of an element are identical to the nodes used for +the definition of a coordinate system as by *DEFINE_- +COORDINATE_NODES, and then rotated about the +shell element normal by an angle BETA. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +XP, YP, ZP +Define coordinates of point p for AOPT = 1 and 4. +A1, A2, A3 +Define components of vector a for AOPT = 2. +V1, V2, V3 +Define components of vector v for AOPT = 3 and 4. +D1, D2, D3 +Define components of vector d for AOPT = 2. +BETA +Material angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA. +Remarks: +This material law is based on standard composite lay-up theory. The implementation, +[Jones 1975], allows the calculation of the force, N, and moment, M, stress resultants +from: +⎧Nx +⎫ +} +{ +Ny +⎬ +⎨ +} +{ +Nxy⎭ +⎩ += +𝐴11 𝐴12 𝐴16 +⎤ +⎡ +𝐴21 𝐴22 𝐴26 +⎥ +⎢ +𝐴16 𝐴26 𝐴66⎦ +⎣ +}}⎫ +{{⎧𝜀𝑥 +𝜀𝑦 +}}⎬ +{{⎨ +0⎭ +𝜀𝑧 +⎩ ++ +𝐵11 𝐵12 𝐵16 +⎤ +⎡ +𝐵21 𝐵22 𝐵26 +⎥ +⎢ +𝐵16 𝐵26 𝐵66⎦ +⎣ +{⎧𝜅x +}⎫ +𝜅y +𝜅z⎭}⎬ +⎩{⎨ +⎧ 𝑀𝑥 +⎫ +} +{ +My +⎬ +⎨ +} +{ +Mxy⎭ +⎩ += +𝐵11 𝐵12 𝐵16 +⎤ +⎡ +𝐵21 𝐵22 𝐵26 +⎥ +⎢ +𝐵16 𝐵26 𝐵66⎦ +⎣ +}}⎫ +{{⎧𝜀𝑥 +𝜀𝑦 +}}⎬ +{{⎨ +0⎭ +𝜀𝑧 +⎩ ++ +𝐷11 𝐷12 𝐷16 +⎤ +𝐷21 𝐷22 𝐷26 +⎥ +𝐷16 𝐷26 𝐷66⎦ +⎡ +⎢ +⎣ +{⎧𝜅x +}⎫ +𝜅y +𝜅z⎭}⎬ +⎩{⎨ +where 𝐴𝑖𝑗 is the extensional stiffness, 𝐷𝑖𝑗is the bending stiffness, and 𝐵𝑖𝑗 is the coupling +stiffness which is a null matrix for symmetric lay-ups. The mid-surface stains and +0 and 𝜅𝑖𝑗respectively. Since these stiffness matrices are +curvatures are denoted by 𝜀𝑖𝑗 +symmetric, 18 terms are needed per shell element in addition to the shell resultants +which are integrated in time. This is considerably less storage than would typically be +required with through thickness integration which requires a minimum of eight history +variables per integration point, e.g., if 100 layers are used 800 history variables would +be stored. Not only is memory much less for this model, but the CPU time required is +also considerably reduced. +*MAT_117 +This is Material Type 117. This material is used for modeling the elastic responses of +composites where a pre-integration is used to compute the extensional, bending, and +coupling stiffness coefficients for use with the Belytschko-Tsay resultant shell +formulation. Since the stresses are not computed in the resultant formulation, the +stresses output to the binary databases for the resultant elements are zero. +NOTE: This material does not support specification of a ma- +terial angle, 𝛽𝑖, for each through-thickness integra- +tion point of a shell. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +4 +5 +6 +7 +8 +3 +4 +5 +6 +7 +8 +Variable +C11 +C12 +C22 +C13 +C23 +C33 +C14 +C24 +Type +F + Card 3 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +C34 +C44 +C15 +C25 +C35 +C45 +C55 +C16 +Type +F + Card 4 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +C26 +C36 +C46 +C56 +C66 +AOPT +Type +F +F +F +F +F +Variable +1 +XP +Type +F + Card 6 +Variable +1 +V1 +Type +F +*MAT_COMPOSITE_MATRIX +2 +YP +F +2 +V2 +F +3 +ZP +F +3 +V3 +F +4 +A1 +F +4 +D1 +F +5 +A2 +F +5 +D2 +F +6 +A3 +F +6 +D3 +F +7 +8 +7 +8 +BETA +F + VARIABLE +DESCRIPTION +MID +RO +CIJ +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +𝐶𝑖𝑗 coefficients of stiffness matrix in the material coordinate +system. +AOPT +Material axes option, see Figure M2-1: +EQ.0.0: locally orthotropic with material axes determined by +element nodes as shown in Figure M2-1. Nodes 1, 2, +and 4 of an element are identical to the nodes used for +the definition of a coordinate system as by *DEFINE_- +COORDINATE_NODES, and then rotated about the +shell element normal by an angle BETA. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector 𝐯 with the +element normal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +VARIABLE +DESCRIPTION +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +XP, YP, ZP +Define coordinates of point 𝐩 for AOPT = 1 and 4. +A1, A2, A3 +Define components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Define components of vector 𝐯 for AOPT = 3 and 4. +D1, D2, D3 +Define components of vector 𝐝 for AOPT = 2. +BETA +Μaterial angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA. +Remarks: +The calculation of the force, 𝑁𝑖𝑗, and moment, 𝑀𝑖𝑗, stress resultants is given in terms of +the membrane strains, 𝜀𝑖 +0, and shell curvatures 𝐶𝑖𝑗, 𝜅𝑖, as: +𝑁𝑥 +⎤ +⎡ +𝑁𝑦 +⎥ +⎢ +⎥ +⎢ +𝑁𝑥𝑦 +⎥ +⎢ +⎥ +⎢ +𝑀𝑥 +⎥ +⎢ +⎥ +⎢ +𝑀𝑦 +⎥ +⎢ +𝑀𝑥𝑦⎦ +⎣ += +𝐶11 𝐶12 𝐶13 𝐶14 𝐶15 𝐶16 +⎤ +⎡ +𝐶21 𝐶22 𝐶23 𝐶24 𝐶25 𝐶26 +⎥ +⎢ +⎥ +⎢ +𝐶31 𝐶32 𝐶33 𝐶34 𝐶35 𝐶36 +⎥ +⎢ +⎥ +⎢ +𝐶41 𝐶42 𝐶43 𝐶44 𝐶45 𝐶46 +⎥ +⎢ +𝐶51 𝐶52 𝐶53 ���54 𝐶55 𝐶56 +⎥ +⎢ +𝐶61 𝐶62 𝐶63 𝐶64 𝐶65 𝐶66⎦ +⎣ +𝜀𝑥 +⎤ +⎡ +𝜀𝑦 +⎥ +⎢ +⎥ +⎢ +⎥ +⎢ +𝜀𝑧 +⎥ +⎢ +κ𝑥 +⎥ +⎢ +𝜅𝑦 +⎥ +⎢ +κ𝑧⎦ +⎣ +where 𝐶𝑖𝑗 = 𝐶𝑗𝑖. In this model this symmetric matrix is transformed into the element +local system and the coefficients are stored as element history variables. In model type +*MAT_COMPOSITE_DIRECT below, the resultants are already assumed to be given in +the element local system which reduces the storage since the 21 coefficients are not +stored as history variables as part of the element data. +The shell thickness is built into the coefficient matrix and, consequently, within the part +ID, which references this material ID, the thickness must be uniform. +*MAT_COMPOSITE_DIRECT +This is Material Type 118. This material is used for modeling the elastic responses of +composites where a pre-integration is used to compute the extensional, bending, and +coupling stiffness coefficients for use with the Belytschko-Tsay resultant shell +formulation. Since the stresses are not computed in the resultant formulation, the +stresses output to the binary databases for the resultant elements are zero. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +4 +5 +6 +7 +8 +3 +4 +5 +6 +7 +8 +Variable +C11 +C12 +C22 +C13 +C23 +C33 +C14 +C24 +Type +F + Card 3 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +C34 +C44 +C15 +C25 +C35 +C45 +C55 +C16 +Type +F + Card 4 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +C26 +C36 +C46 +C56 +C66 +Type +F +F +F +F +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +VARIABLE +DESCRIPTION +CIJ +𝐶𝑖𝑗coefficients of the stiffness matrix. +Remarks: +The calculation of the force, 𝑁𝑖𝑗, and moment, 𝑀𝑖𝑗, stress resultants is given in terms of +the membrane strains, 𝜀𝑖 +⎫ +0, and shell curvatures, 𝜅𝑖, as: +⎧𝑁𝑥 +𝑁𝑦 +𝑁𝑥𝑦 +𝑀𝑥 +𝑀𝑦 +𝑀𝑥𝑦⎭ +𝐶11 𝐶12 𝐶13 𝐶14 𝐶15 𝐶16 +⎤ +⎡ +𝐶21 𝐶22 𝐶23 𝐶24 𝐶25 𝐶26 +⎥ +⎢ +⎥ +⎢ +𝐶31 𝐶32 𝐶33 𝐶34 𝐶35 𝐶36 +⎥ +⎢ +⎥ +⎢ +𝐶41 𝐶42 𝐶43 𝐶44 𝐶45 𝐶46 +⎥ +⎢ +𝐶51 𝐶52 𝐶53 𝐶54 𝐶55 𝐶56 +⎥ +⎢ +𝐶61 𝐶62 𝐶63 𝐶64 𝐶65 𝐶66⎦ +⎣ +{{{{{ +{{{{{ +}}}}} +}}}}} += +⎬ +⎨ +⎩ +⎫ +⎧𝜀𝑥 +𝜀𝑦 +𝜀𝑧 +𝜅𝑥 +𝜅𝑦 +𝜅𝑥𝑦⎭ +}}}}} +}}}}} +{{{{{ +{{{{{ +⎩ +⎨ +⎬ +where 𝐶𝑖𝑗 = 𝐶𝑗𝑖. In this model the stiffness coefficients are already assumed to be given +in the element local system which reduces the storage. Great care in the element +orientation and choice of the local element system, see *CONTROL_ACCURACY, must +be observed if this model is used. +The shell thickness is built into the coefficient matrix and, consequently, within the part +ID, which references this material ID, the thickness must be uniform. +*MAT_GENERAL_NONLINEAR_6DOF_DISCRETE_BEAM +This is Material Type 119. This is a very general spring and damper model. This beam + Additional +the MAT_SPRING_GENERAL_NONLINEAR option. +is based on +unloading options have been included. The two nodes defining the beam may be +coincident to give a zero length beam, or offset to give a finite length beam. For finite +length discrete beams the absolute value of the variable SCOOR in the SECTION_- +BEAM input should be set to a value of 2.0 or 3.0 to give physically correct behavior. A +triad is used to orient the beam for the directional springs. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +KT +F +3 +4 +KR +F +4 +5 +6 +7 +8 +IUNLD +OFFSET +DAMPF +IFLAG +I +5 +F +6 +F +7 +I +8 +Variable +LCIDTR +LCIDTS +LCIDTT +LCIDRR +LCIDRS +LCIDRT +Type +I + Card 3 +1 +I +2 +I +3 +I +4 +I +5 +I +6 +7 +8 +Variable +LCIDTUR LCIDTUS LCIDTUT LCIDRUR LCIDRUS LCIDRUT +Type +I + Card 4 +1 +I +2 +I +3 +I +4 +I +5 +I +6 +7 +8 +Variable +LCIDTDR LCIDTDS LCIDTDT LCIDRDR LCIDRDS LCIDRDT +Type +I +I +I +I +I +Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCIDTER +LCIDTES +LCIDTET +LCIDRER LCIDRES LCIDRET +Type +I + Card 6 +1 +I +2 +I +3 +I +4 +I +5 +I +6 +7 +8 +Variable +UTFAILR UTFAILS UTFAILT WTFAILR WTFAILS WTFAILT +Type +F + Card 7 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +7 +8 +Variable +UCFAILR UCFAILS UCFAILT WCFAILR WCFAILS WCFAILT +Type +F + Card 8 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +7 +8 +Variable +IUR +IUS +IUT +IWR +IWS +IWT +Type +F +F +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +KT +KR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density, see also volume in *SECTION_BEAM definition. +Translational stiffness for unloading option 2.0. +Rotational stiffness for unloading option 2.0. +DAMPF +IFLAG +*MAT_GENERAL_NONLINEAR_6DOF_DISCRETE_BEAM +DESCRIPTION +Damping factor for stability. Values in the neighborhood of unity +are recommended. This damping factor is properly scaled to +eliminate time step size dependency. Also, it is active if and only +if the local stiffness is defined. +Flag for switching between the displacement (default IFLAG = 0) +and linear strain (IFLAG = 1) formulations. The displacement +formulation is the one used in all other models. For the linear +strain formulation, the displacements and velocities are divided +by the initial length of the beam. +IUNLD +Unloading option (Also see Figure M119-1.): +EQ.0.0: Loading and unloading follow loading curve +EQ.1.0: Loading follows loading curve, unloading follows +unloading curve. The unloading curve ID if undefined +is taken as the loading curve. +EQ.2.0: Loading follows loading curve, unloading follows +unloading stiffness, KT or KR, to the unloading curve. +The loading and unloading curves may only intersect +at the origin of the axes. +EQ.3.0: Quadratic unloading from peak displacement value to +a permanent offset. +OFFSET +LCIDTR +if +the +Offset factor between 0 and 1.0 to determine permanent set upon +in +unloading +compression and tension are equal to the product of this offset +value and the maximum compressive and tensile displacements, +respectively. + The permanent sets +IUNLD = 3.0. +Load curve ID defining translational force resultant along local r- +axis versus relative translational displacement. If zero, no +stiffness related forces are generated for this degree of freedom. +The loading curves must be defined from the most negative +displacement to the most positive displacement. The force does +not need to increase monotonically. The curves in this input are +linearly extrapolated when the displacement range falls outside +the curve definition. +LCIDTS +Load curve ID defining translational force resultant along local s- +axis versus relative translational displacement. +VARIABLE +LCIDTT +LCIDRR +LCIDRS +LCIDRT +LCIDTUR +DESCRIPTION +Load curve ID defining translational force resultant along local t- +axis versus relative translational displacement. +Load curve ID defining rotational moment resultant about local r- +axis versus relative rotational displacement. +Load curve ID defining rotational moment resultant about local s- +axis versus relative rotational displacement. +Load curve ID defining rotational moment resultant about local t- +axis versus relative rotational displacement. +this curve must +force values defined by +Load curve ID defining translational force resultant along local r- +axis versus relative translational displacement during unloading. +The +increase +monotonically from the most negative displacement to the most +positive displacement. For IUNLD = 1.0, the slope of this curve +must equal or exceed the loading curve for stability reasons. This +is not the case for IUNLD = 2.0. For loading and unloading to +follow the same path simply set LCIDTUR = LCIDTR. For options +IUNLD = 0.0 or 3.0 the unloading curve is not required. For +IUNLD = 2.0, if LCIDTUR is left blank or zero, the default is to +use the same curve for unloading as for loading. +LCIDTUS +LCIDTUT +LCIDRUR +LCIDRUS +LCIDRUT +LCIDTDR +LCIDTDS +Load curve ID defining translational force resultant along local s- +axis versus relative translational displacement during unloading. +Load curve ID defining translational force resultant along local t- +axis versus relative translational displacement during unloading. +Load curve ID defining rotational moment resultant about local r- +axis versus relative rotational displacement during unloading. +Load curve ID defining rotational moment resultant about local s- +axis versus relative rotational displacement during unloading. +Load curve ID defining rotational moment resultant about local t- +axis versus relative rotational displacement during unloading. If +zero, no viscous forces are generated for this degree of freedom. +Load curve ID defining translational damping force resultant +along local r-axis versus relative translational velocity. +Load curve ID defining translational damping force resultant +along local s-axis versus relative translational velocity. +LCIDTDT +LCIDRDR +LCIDRDS +LCIDRDT +LCIDTER +LCIDTES +LCIDTET +LCIDRER +LCIDRES +LCIDRET +UTFAILR +UTFAILS +UTFAILT +WTFAILR +*MAT_GENERAL_NONLINEAR_6DOF_DISCRETE_BEAM +DESCRIPTION +Load curve ID defining translational damping force resultant +along local t-axis versus relative translational velocity. +Load curve ID defining rotational damping moment resultant +about local r-axis versus relative rotational velocity. +Load curve ID defining rotational damping moment resultant +about local s-axis versus relative rotational velocity. +Load curve ID defining rotational damping moment resultant +about local t-axis versus relative rotational velocity. +Load curve ID defining translational damping force scale factor +versus relative displacement in local r-direction. +Load curve ID defining translational damping force scale factor +versus relative displacement in local s-direction. +Load curve ID defining translational damping force scale factor +versus relative displacement in local t-direction. +Load curve ID defining rotational damping moment resultant +scale factor versus relative displacement in local r-rotation. +Load curve ID defining rotational damping moment resultant +scale factor versus relative displacement in local s-rotation. +Load curve ID defining rotational damping moment resultant +scale factor versus relative displacement in local t-rotation. +Optional, translational displacement at failure in tension. If zero, +the corresponding displacement, ur, is not considered in the +failure calculation. +Optional, translational displacement at failure in tension. If zero, +the corresponding displacement, us, is not considered in the +failure calculation. +Optional, translational displacement at failure in tension. If zero, +the corresponding displacement, ut, is not considered in the +failure calculation. +Optional, rotational displacement at failure in tension. If zero, the +corresponding rotation, θr, is not considered in the failure +calculation. +VARIABLE +WTFAILS +WTFAILT +UCFAILR +UCFAILS +UCFAILT +WCFAILR +WCFAILS +WCFAILT +IUR +IUS +IUT +IWR +IWS +IWT +DESCRIPTION +Optional, rotational displacement at failure in tension. If zero, the +corresponding rotation, θs, is not considered in the failure +calculation. +Optional rotational displacement at failure in tension. If zero, the +corresponding rotation, θt, is not considered in the failure +calculation. +Optional, translational displacement at failure in compression. If +zero, the corresponding displacement, ur, is not considered in the +failure calculation. Define as a positive number. +Optional, translational displacement at failure in compression. If +zero, the corresponding displacement, us, is not considered in the +failure calculation. Define as a positive number. +Optional, translational displacement at failure in compression. If +zero, the corresponding displacement, ut, is not considered in the +failure calculation. Define as a positive number. +Optional, rotational displacement at failure in compression. If +zero, the corresponding rotation, θr, is not considered in the +failure calculation. Define as a positive number. +Optional, rotational displacement at failure in compression. If +zero, the corresponding rotation, θs, is not considered in the +failure calculation. Define as a positive number. +Optional, rotational displacement at failure in compression. If +zero, the corresponding rotation, θt, is not considered in the +failure calculation. Define as a positive number. +Initial translational displacement along local r-axis. +Initial translational displacement along local s-axis. +Initial translational displacement along local t-axis. +Initial rotational displacement about the local r-axis. +Initial rotational displacement about the local s-axis. +Initial rotational displacement about the local t-axis. +*MAT_GENERAL_NONLINEAR_6DOF_DISCRETE_BEAM +Catastrophic failure, which is based on displacement resultants, occurs if either of the +following inequalities are satisfied: +) +( +𝑢𝑟 +tfail +𝑢𝑟 ++ ( +𝑢𝑠 +tfail +𝑢𝑠 +) ++ ( +𝑢𝑡 +tfail +𝑢𝑡 +) ++ ( +𝜃𝑟 +tfail +𝜃𝑟 +) ++ ( +) ++ +𝜃𝑠 +tfail +𝜃𝑠 +⎜⎛ 𝜃𝑡 +𝑡𝑓𝑎𝑖𝑙 +𝜃𝑡 +⎝ +⎟⎞ +⎠ +( +𝑢𝑟 +cfail +𝑢𝑟 +) ++ ( +𝑢𝑠 +cfail +𝑢𝑠 +) ++ ( +𝑢𝑡 +cfail +𝑢𝑡 +) ++ ( +𝜃𝑟 +cfail +𝜃𝑟 +) ++ ( +𝜃𝑠 +cfail +𝜃𝑠 +) ++ ( +𝜃𝑡 +cfail +𝜃𝑡 +− 1. ≥ 0 +) +− 1. ≥ 0 +After failure the discrete element is deleted. If failure is included either the tension +failure or the compression failure or both may be used. +Unload = 0 +Loading-unloading +curve +Unload = 2 +Unloading +curve +DISPLACEMENT +Unloading +curve +DISPLACEMENT +Unload = 1 +Unload = 3 +DISPLACEMENT +umin +× OFFSET +umin +Quadratic +unloading +DISPLACEMENT +Figure M119-1. Load and unloading behavior. +There are two formulations for calculating the force. The first is the standard +displacement formulation, where, for example, the force in a linear spring is +𝐹 = −𝐾Δℓ +for a change in length of the beam of Δℓ. The second formulation is based on the linear +strain, giving a force of +𝐹 = −𝐾 +Δℓ +ℓ0 +for a beam with an initial length of ℓ0. This option is useful when there are springs of +different lengths but otherwise similar construction since it automatically reduces the +stiffness of the spring as the length increases, allowing an entire family of springs to be +modeled with a single material. Note that all the displacement and velocity +components are divided by the initial length, and therefore the scaling applies to the +damping and rotational stiffness. +*MAT_GURSON +This is Material Type 120. This is the Gurson dilatational-plastic model. This model is +available for shell and solid elements. A detailed description of this model can be +found in the following references: Gurson [1975, 1977], Chu and Needleman [1980] and +Tvergaard and Needleman [1984]. The implementation in LS-DYNA is based on the +implementation of Feucht [1998] and Faßnacht [1999], which was recoded at LSTC. +Strain rate dependency can be defined via a Table definition. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +SIGY +F +6 +N +F +7 +Q1 +F +8 +Q2 +F +Default +none +none +none +none +none +0.0 +none +none + Card 2 +Variable +Type +Default +1 +FC +F +0 + Card 3 +1 +2 +F0 +F +0 +2 +3 +EN +F +0 +3 +4 +SN +F +0 +4 +5 +FN +F +0 +5 +6 +7 +8 +ETAN +ATYP +FF0 +F +0 +6 +F +0 +7 +F +0 +8 +Variable +EPS1 +EPS2 +EPS3 +EPS4 +EPS5 +EPS6 +EPS7 +EPS8 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ES1 +ES2 +ES3 +ES4 +ES5 +ES6 +ES7 +ES8 +Type +Default + Card 5 +Variable +Type +Default +F +0 +1 +L1 +F +0 + Card 6 +1 +F +0 +2 +L2 +F +0 +2 +F +0 +3 +L3 +F +0 +3 +F +0 +4 +L4 +F +0 +4 +F +0 +5 +F +0 +6 +F +0 +7 +F +0 +8 +FF1 +FF2 +FF3 +FF4 +F +0 +5 +F +0 +6 +F +0 +7 +F +0 +8 +Variable +LCSS +LCLF +NUMINT +LCF0 +LCFC +LCFN +VGTYP +DEXP +Type +Default +F +0 +F +0 +F +1.0 +F +0 +F +0 +F +0 +F +0 +F +3.0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +SIGY +N +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +Yield stress. +Exponent for Power law. This value is only used if ATYP = 1 and +LCSS = 0. +Q1 +Q2 +FC +F0 +EN +*MAT_GURSON +DESCRIPTION +Gurson flow function parameter 𝑞1. +Gurson flow function parameter 𝑞2. +Critical void volume fraction 𝑓𝑐 where voids begin to aggregate. +This value is only used if LCFC = 0. +Initial void volume fraction 𝑓0. This value is only used if LCF0 = 0. +Mean nucleation strain 𝜀𝑁. +GT.0.0: Constant value, +LT.0.0: Load curve ID = (-EN) which defines mean nucleation +strain 𝜀𝑁 as a function of element length. +SN +Standard deviation 𝑠𝑁 of the normal distribution of 𝜀𝑁. +GT.0.0: Constant value, +LT.0.0: Load curve +ID = (-SN) which defines standard +deviation 𝑠𝑁 of the normal distribution of 𝜀𝑁 as a func- +tion of element length. +FN +ETAN +Void volume fraction of nucleating particles 𝑓𝑁. This value is only +used if LCFN = 0. +Hardening modulus. This value is only used if ATYP = 2 and +LCSS = 0. +ATYP +Type of hardening. +EQ.0.0: Ideal plastic, +EQ.1.0: Power law, +𝜎𝑌 = SIGY. +𝜎𝑌 = SIGY × ( +𝜀𝑝 + SIGY/E +SIGY/E +1/N +) +EQ.2.0: Linear hardening, +𝜎𝑌 = SIGY + +E × ETAN +E − ETAN +𝜀𝑝. +EQ.3.0: 8 points curve. +FF0 +Failure void volume fraction 𝑓𝐹. This value is only used if no +curve is given by (L1, FF1) – (L4, FF4) and LCFF = 0. +EPS1 - EPS8 +*MAT_120 +DESCRIPTION +Effective plastic strain values. The first point must be zero +corresponding to the initial yield stress. At least 2 points should +be defined. These values are used if ATYP = 3 and LCSS = 0. +ES1 - ES8 +Corresponding yield stress values to EPS1 – EPS8. These values +are used if ATYP = 3 and LCSS = 0. +L1 - L4 +Element length values. These values are only used if LCFF = 0 +FF1 - FF4 +LCSS +LCFF +NUMINT +Corresponding failure void volume fraction. These values are +only used if LCFF = 0. +Load curve ID or Table ID. ATYP is ignored with this option. +Load curve ID defining effective stress versus effective plastic +strain. Table ID defines for each strain rate value a load curve ID +giving the effective stress versus effective plastic strain for that +rate . The stress-strain curve for the lowest value +of strain rate is used if the strain rate falls below the minimum +value. Likewise, the stress-strain curve for the highest value of +strain rate is used if the strain rate exceeds the maximum value. +NOTE: The strain rate values defined in the table may be given as +the natural logarithm of the strain rate. If the first stress-strain +curve in the table corresponds to a negative strain rate, LS-DYNA +assumes that the natural logarithm of the strain rate value is used. +Since the tables are internally discretized to equally space the +points, natural logarithms are necessary, for example, if the +curves correspond to rates from 10−4 to 104. +Load curve ID defining failure void volume fraction 𝑓𝐹 versus +element length. +Number of integration points which must fail before the element +is deleted. This option is available for shells and solids. +LT.0.0: |NUMINT| is percentage of integration points/layers +which must fail before shell element fails. For fully in- +tegrated shells, a methodology is used where a layer +fails if one integration point fails and then the given +percentage of layers must fail before the element fails. +Only available for shells. +LCF0 +Load curve ID defining initial void volume fraction 𝑓0 versus +element length. +LCFC +LCFN +*MAT_GURSON +DESCRIPTION +Load curve ID defining critical void volume fraction 𝑓𝑐 versus +element length. +Load curve ID defining void volume fraction of nucleating +particles 𝑓𝑁 versus element length. +VGTYP +Type of void growth behavior. +EQ.0.0: Void growth in case of tension and void contraction in +case of compression, but never below 𝑓0 (default). +EQ.1.0: Void growth only in case of tension. +EQ.2.0: Void growth in case of tension and void contraction in +case of compression, even below 𝑓0. +DEXP +Exponent value for damage history variable 16. +Remarks: +The Gurson flow function is defined as: +Φ = +𝜎𝑀 +2 + 2𝑞1𝑓 ∗cosh ( +𝜎𝑌 +3𝑞2𝜎𝐻 +2𝜎𝑌 +) − 1 − (𝑞1𝑓 ∗)2 = 0 +where 𝜎𝑀 is the equivalent von Mises stress, 𝜎𝑌 is the yield stress, 𝜎𝐻 is the mean +hydrostatic stress. The effective void volume fraction is defined as +𝑓 ∗(𝑓 ) = +⎧𝑓 +{ +⎨ +{ +⎩ +𝑓𝑐 + +1/𝑞1 − 𝑓𝑐 +𝑓𝐹 − 𝑓𝑐 +𝑓 ≤ 𝑓𝑐 +(𝑓 − 𝑓𝑐) +𝑓 > 𝑓c +The growth of void volume fraction is defined as +𝐺 + 𝑓 ̇ +𝑁 +where the growth of existing voids is defined as +𝑓 ̇ = 𝑓 ̇ +𝑝 +𝑓 ̇ +𝐺 = (1 − 𝑓 )𝜀̇𝑘𝑘 +and nucleation of new voids is defined as +𝑓 ̇ +𝑁 = 𝐴𝜀̇𝑝 +with function A +𝐴 = +𝑓𝑁 +𝑆𝑁√2𝜋 +exp [− +( +𝜀𝑝 − 𝜀𝑁 +𝑆𝑁 +) +] +Voids are nucleated only in tension. +History variables: + Shell / Solid Description +1 / 1 +4 / 2 +5 / 3 +6 / 4 +7 / 5 +Void volume fraction +Triaxiality variable σH/σM +Effective strain rate +Growth of voids +Nucleation of voids +11 / 11 +Dimensionless material damage value = +{⎧ (f−f0) +(fc−f0) +{⎨ +1 + +⎩ +(f−fc) +(fF−fc) +𝑓 ≤ 𝑓c +𝑓 > 𝑓c +13 / 13 +Deviatoric part of microscopic plastic strain +14 / 14 +Volumetric part of macroscopic plastic strain +16 / 16 +Dimensionless material damage value = ( +𝑓 −𝑓0 +𝑓𝐹−𝑓0 +1/DEXP +) +*MAT_GURSON_JC +This is an enhancement of Material Type 120. This is the Gurson model with additional +Johnson-Cook failure criterion (parameters Card 5). This model is available for shell +and solid elements. Strain rate dependency can be defined via a table. An extension for +void growth under shear-dominated states and for Johnson-Cook damage evolution is +optional. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +SIGY +F +6 +N +F +7 +Q1 +F +8 +Q2 +F +Default +none +none +none +none +none +0.0 +none +none + Card 2 +Variable +Type +Default +1 +FC +F +0 + Card 3 +1 +2 +F0 +F +0 +2 +3 +EN +F +0 +3 +4 +SN +F +0 +4 +5 +FN +F +0 +5 +6 +7 +8 +ETAN +ATYP +FF0 +F +0 +6 +F +0 +7 +F +0 +8 +Variable +EPS1 +EPS2 +EPS3 +EPS4 +EPS5 +EPS6 +EPS7 +EPS8 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SIG1 +SIG2 +SIG3 +SIG4 +SIG5 +SIG6 +SIG7 +SIG8 +Type +Default +F +0 + Card 5 +1 +Variable +LCDAM +Type +Default +F +0 + Card 6 +1 +F +0 +2 +L1 +F +0 +2 +F +0 +3 +L2 +F +0 +3 +F +0 +4 +D1 +F +0 +4 +F +0 +5 +D2 +F +0 +5 +F +0 +6 +D3 +F +0 +6 +F +0 +7 +D4 +F +0 +7 +F +0 +8 +LCJC +F +0 +8 +Variable +LCSS +LCFF +NUMINT +LCF0 +LCFC +LCFN +VGTYP +DEXP +Type +Default +F +0 +F +0 +F +1 +F +0 +F +0 +F +0 +F +0 +F +3.0 +Optional Card (starting with version 971 release R4) +4 +5 +6 +7 +8 + Card 7 +1 +2 +Variable +KW +BETA +Type +Default +F +0 +F +0 +3 +M +F +1.0 +VARIABLE +DESCRIPTION +MID +RO +E +PR +SIGY +N +Q1 +Q2 +FC +F0 +EN +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +Yield stress. +Exponent for Power law. This value is only used if ATYP = 1 and +LCSS = 0. +Gurson flow function parameter 𝑞1. +Gurson flow function parameter 𝑞2. +Critical void volume fraction 𝑓𝑐 where voids begin to aggregate. +Initial void volume fraction 𝑓0. This value is only used if LCF0 = 0. +Mean nucleation strain 𝜀𝑁. +GT.0.0: Constant value, +LT.0.0: Load curve ID = (-EN) which defines mean nucleation +strain 𝜀𝑁 as a function of element length. +SN +Standard deviation 𝑠𝑁 of the normal distribution of 𝜀𝑁. +GT.0.0: Constant value, +LT.0.0: Load curve +ID = (-SN) which defines standard +deviation 𝑠𝑁 of the normal distribution of 𝜀𝑁 as a func- +tion of element length. +FN +ETAN +Void volume fraction of nucleating particles𝑓𝑁. This value is only +used if LCFN = 0. +Hardening modulus. This value is only used if ATYP = 2 and +LCSS = 0. +VARIABLE +DESCRIPTION +ATYP +Type of hardening. +EQ.0.0: Ideal plastic, +EQ.1.0: Power law, +𝜎𝑌 = SIGY. +𝜎𝑌 = SIGY × ( +𝜀𝑝 + SIGY/E +SIGY/E +1/N +) +EQ.2.0: Linear hardening, +𝜎𝑌 = SIGY + +E × ETAN +E − ETAN +𝜀𝑝. +EQ.3.0: 8 points curve. +FF0 +Failure void volume fraction 𝑓𝐹. This value is only used if +LCFF = 0. +EPS1 - EPS8 +Effective plastic strain values. The first point must be zero +corresponding to the initial yield stress. At least 2 points should +be defined. These values are used if ATYP = 3 and LCSS = 0. +ES1 - ES8 +LCDAM +L1 +L2 +Corresponding yield stress values to EPS1 – EPS8. These values +are used if ATYP = 3 and LCSS = 0. +Load curve defining scaling factor Λ versus element length. +Scales the Johnson-Cook failure strain . + If +LCDAM = 0, no scaling is performed. +Lower triaxiality factor defining failure evolution (Johnson-Cook). +Upper triaxiality factor defining failure evolution (Johnson-Cook). +D1 - D4 +Johnson-Cook damage parameters. +LCJC +Load curve defining scaling factor for Johnson-Cook failure +versus triaxiality . If LCJC > 0, parameters D1, D2 +and D3 are ignored. +VARIABLE +LCSS +LCFF +NUMINT +LCF0 +LCFC +LCFN +DESCRIPTION +Load curve ID or Table ID. ATYP is ignored with this option. +Load curve ID defining effective stress versus effective plastic +strain. Table ID defines for each strain rate value a load curve ID +giving the effective stress versus effective plastic strain for that +rate . The stress-strain curve for the lowest value +of strain rate is used if the strain rate falls below the minimum +value. Likewise, the stress-strain curve for the highest value of +strain rate is used if the strain rate exceeds the maximum value. +NOTE: The strain rate values defined in the table may be given as +the natural logarithm of the strain rate. If the first stress-strain +curve in the table corresponds to a negative strain rate, LS-DYNA +assumes that the natural logarithm of the strain rate value is used. +Since the tables are internally discretized to equally space the +points, natural logarithms are necessary, for example, if the +curves correspond to rates from 10−4 to 104. +Load curve ID defining failure void volume fraction 𝑓𝐹 versus +element length. +Number of through thickness integration points which must fail +before the element is deleted. This option is available for shells +and solids. +LT.0.0: |NUMINT| is percentage of integration points/layers +which must fail before shell element fails. For fully in- +tegrated shells, a methodology is used where a layer +fails if one integration point fails and then the given +percentage of layers must fail before the element fails. +Only available for shells. +Load curve ID defining initial void volume fraction 𝑓0 versus +element length. +Load curve ID defining critical void volume fraction 𝑓𝑐 versus +element length. +Load curve ID defining void volume fraction of nucleating +particles 𝑓𝑁 versus element length. +VARIABLE +DESCRIPTION +VGTYP +Type of void growth behavior. +EQ.0.0: Void growth in case of tension and void contraction in +case of compression, but never below 𝑓0 (default). +EQ.1.0: Void growth only in case of tension. +EQ.2.0: Void growth in case of tension and void contraction in +case of compression, even below 𝑓0. +DEXP +Exponent value for damage history variable 16. +KW +Parameter kω for void growth in shear-dominated states. See +remarks. +BETA +Parameter β in Lode cosine function. See remarks. +M +Parameter for generalization of Johnson-Cook damage evolution. +See remarks. +Remarks: +The Gurson flow function is defined as: +Φ = +𝜎𝑀 +2 + 2𝑞1𝑓 ∗cosh ( +𝜎𝑌 +3𝑞2𝜎𝐻 +2𝜎𝑌 +) − 1 − (𝑞1𝑓 ∗)2 = 0 +where 𝜎𝑀 is the equivalent von Mises stress, 𝜎𝑌 is the yield stress, 𝜎𝐻 is the mean +hydrostatic stress. The effective void volume fraction is defined as +𝑓 ∗(𝑓 ) = +⎧𝑓 +{ +⎨ +{ +⎩ +𝑓𝑐 + +1/𝑞1 − 𝑓𝑐 +𝑓𝐹 − 𝑓𝑐 +𝑓 ≤ 𝑓𝑐 +(𝑓 − 𝑓𝑐) +𝑓 > 𝑓c +The growth of void volume fraction is defined as +𝐺 + 𝑓 ̇ +𝑁 +where the growth of existing voids is defined as +𝑓 ̇ = 𝑓 ̇ +𝑓 ̇ +𝐺 = (1 − 𝑓 )𝜀̇𝑘𝑘 +𝑝 + 𝑘𝜔𝜔(σ)𝑓 (1 − 𝑓 )𝜀̇𝑀 +𝑝𝑙 𝜎𝑌 +𝜎𝑀 +The second term is an optional extension for shear failure proposed by Nahshon and +Hutchinson [2008] with new parameter 𝑘𝜔 (=0 by default), effective plastic strain rate in +the matrix 𝜀̇𝑀 +𝑝𝑙 , and Lode cosin function 𝜔(σ): +𝜔(σ) = 1 − 𝜉 2 − 𝛽 ⋅ 𝜉 (1 − 𝜉 ), 𝜉 = cos(3𝜃) = +27 +𝐽3 +3 +𝜎𝑀 +with parameter 𝛽, Lode angle 𝜃 and third deviatoric stress invariant 𝐽3. +Nucleation of new voids is defined as +𝑝𝑙 +𝑓 ̇ +𝑁 = 𝐴𝜀̇𝑀 +with function A +𝐴 = +𝑓𝑁 +𝑆𝑁√2𝜋 +exp +⎜⎜⎛𝜀𝑀 +2 ⎝ +𝑝𝑙 − 𝜀𝑁 +⎟⎟⎞ +𝑆𝑁 ⎠ +⎡ +− +⎢⎢ +⎣ +⎤ +⎥⎥ +⎦ +Voids are nucleated only in tension. +The Johnson-Cook failure criterion is added in this material model. Based on the +triaxiality ratio 𝜎𝐻/𝜎𝑀 failure is calculated as: +𝜎𝐻/𝜎𝑀 > 𝐿1 : Gurson model +𝐿1 ≥ 𝜎𝐻/𝜎𝑀 ≥ 𝐿2 : Gurson model and Johnson-Cook failure criteria +𝐿2 < 𝜎𝐻/𝜎𝑀 +: Gurson model +Johnson-Cook failure strain is defined as +𝜀𝑓 = [𝐷1 + 𝐷2exp (𝐷3 +𝜎𝐻 +𝜎𝑀 +)] (1 + 𝐷4ln 𝜀̇)Λ +where 𝐷1, 𝐷2, 𝐷3 and 𝐷4 are the Johnson-Cook failure parameters and Λ is a function +for including mesh-size dependency. An alternative expression can be used, where the +first term of the above equation (including D1, D2 and D3) is replaced by a general +function LCJC which depends on triaxiality +𝜎𝐻 +𝜎𝑀 +) (1 + 𝐷4ln𝜀̇)Λ +𝜀𝑓 = LCJC × ( +The Johnson-Cook damage parameter 𝐷𝑓 is calculated with the following evolution +equation: +𝐷̇ 𝑓 = +𝜀̇𝑝𝑙 +𝜀𝑓 +⇒ 𝐷𝑓 = ∑ +Δ𝜀𝑝𝑙 +𝜀𝑓 +. +where 𝛥𝜀𝑝𝑙 is the increment in effective plastic strain. The material fails when 𝐷𝑓 +reaches 1.0. A more general (non-linear) damage evolution is possible if 𝑀 > 1 is +chosen: +𝐷̇ 𝑓 = +(1− 1 +𝐷𝑓 +) +𝜀̇𝑝𝑙, +𝜀𝑓 +𝑀 ≥ 1.0 +Shell / Solid Description +*MAT_120_JC +1 / 1 +4 / 2 +5 / 3 +6 / 4 +7 / 5 +8 / 6 +9 / 7 +0 / 8 +Void volume fraction +Triaxiality variable σH/σM +Effective strain rate +Growth of voids +Nucleation of voids +Johnson-Cook failure strain εf +Johnson-Cook damage parameter Df +Domain variable: +EQ.0  elastic stress update +EQ.1  region (a) Gurson +EQ.2  region (b) Gurson + Johnson-Cook +EQ.3  region (c) Gurson +11 / 11 +Dimensionless material damage value = +{⎧ (f−f0) +(fc−f0) +{⎨ +1 + +⎩ +(f−fc) +(fF−fc) +𝑓 ≤ 𝑓c +𝑓 > 𝑓c +13 / 13 +Deviatoric part of microscopic plastic strain +14 / 14 +Volumetric part of macroscopic plastic strain +16 / 16 +Dimensionless material damage value = ( +1/DEXP +f−f0 +fF−f0 +) +*MAT_GURSON_RCDC +This is an enhancement of material Type 120. This is the Gurson model with the +Wilkins Rc-Dc [Wilkins, et al., 1977] fracture model added. This model is available for +shell and solid elements. A detailed description of this model can be found in the +following references: Gurson [1975, 1977]; Chu and Needleman [1980]; and Tvergaard +and Needleman [1984]. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +SIGY +F +6 +N +F +7 +Q1 +F +8 +Q2 +F +Default +none +none +none +none +none +0.0 +none +none + Card 2 +Variable +Type +Default +1 +FC +F +0 + Card 3 +1 +2 +F0 +F +0 +2 +3 +EN +F +0 +3 +4 +SN +F +0 +4 +5 +FN +F +0 +5 +6 +7 +8 +ETAN +ATYP +FF0 +F +0 +6 +F +0 +7 +F +0 +8 +Variable +EPS1 +EPS2 +EPS3 +EPS4 +EPS5 +EPS6 +EPS7 +EPS8 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ES1 +ES2 +ES3 +ES4 +ES5 +ES6 +ES7 +ES8 +Type +Default + Card 5 +Variable +Type +Default +F +0 +1 +L1 +F +0 + Card 6 +1 +F +0 +2 +L2 +F +0 +2 +F +0 +3 +L3 +F +0 +3 +Variable +LCSS +LCLF +NUMINT +Type +Default +F +0 + Card 7 +1 +F +0 +2 +F +1 +3 +F +0 +4 +L4 +F +0 +4 +4 +Variable +ALPHA +BETA +GAMMA +D0 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +5 +F +0 +6 +F +0 +7 +F +0 +8 +FF1 +FF2 +FF3 +FF4 +F +0 +5 +5 +B +F +0 +F +0 +6 +F +0 +7 +6 +7 +LAMBDA +DS +F +0 +F +0 +F +0 +8 +8 +L +F +VARIABLE +DESCRIPTION +MID +RO +E +PR +SIGY +N +Q1 +Q1 +FC +F0 +EN +SN +FN +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +Yield stress. +Exponent for Power law. This value is only used if ATYP = 1 and +LCSS = 0. +Parameter 𝑞1. +Parameter 𝑞2. +Critical void volume fraction 𝑓𝑐 +Initial void volume fraction 𝑓0. +Mean nucleation strain𝜀𝑁. +Standard deviation 𝑆𝑁 of the normal distribution of 𝜀𝑁. +Void volume fraction of nucleating particles. +ETAN +Hardening modulus. This value is only used if ATYP = 2 and +LCSS = 0. +ATYP +Type of hardening. +EQ.0.0: Ideal plastic, +EQ.1.0: Power law, +𝜎𝑌 = SIGY. +𝜎𝑌 = SIGY × ( +𝜀𝑝 + SIGY/E +SIGY/E +1/N +) +EQ.2.0: Linear hardening, +𝜎𝑌 = SIGY + +E × ETAN +E − ETAN +𝜀𝑝. +EQ.3.0: 8 points curve. +FF0 +Failure void volume fraction. This value is used if no curve is +given by the points (L1, FF1) – (L4, FF4) and LCLF = 0. +VARIABLE +EPS1 - EPS8 +DESCRIPTION +Effective plastic strain values. The first point must be zero +corresponding to the initial yield stress. This option is only used +if ATYP equal to 3. At least 2 points should be defined. These +values are used if ATYP = 3 and LCSS = 0. +ES1 - ES8 +Corresponding yield stress values to EPS1 - EPS8. These values +are used if ATYP = 3 and LCSS = 0. +L1 - L4 +Element length values. These values are only used if LCLF = 0. +FF1 - FF4 +Corresponding failure void volume fraction. These values are +only used if LCLF = 0. +LCSS +LCLF +Load curve ID defining effective stress versus effective plastic +strain. ATYP is ignored with this option. +Load curve ID defining failure void volume fraction versus +element length. The values L1 - L4 and FF1 - FF4 are ignored +with this option. +NUMINT +Number of through thickness integration points which must fail +before the element is deleted. +ALPHA +Parameter 𝛼. for the Rc-Dc model +BETA +Parameter𝛽. for the Rc-Dc model +GAMMA +Parameter 𝛾. for the Rc-Dc model +D0 +B +Parameter 𝐷0. for the Rc-Dc model +Parameter 𝑏. for the Rc-Dc model +LAMBDA +Parameter 𝜆. for the Rc-Dc model +Parameter 𝐷𝑠. for the Rc-Dc model +Characteristic element length for this material +DS +L +Remarks: +The Gurson flow function is defined as: +Φ = +𝜎𝑀 +2 + 2𝑞1𝑓 ∗cosh ( +𝜎𝑌 +3𝑞2𝜎𝐻 +2𝜎𝑌 +) − 1 − (𝑞1𝑓 ∗)2 = 0 +where 𝜎𝑀 is the equivalent von Mises stress, 𝜎𝑌 is the Yield stress, 𝜎𝐻 is the mean +hydrostatic stress. The effective void volume fraction is defined as +𝑓 ∗(𝑓 ) = +⎧𝑓 +{ +⎨ +{ +⎩ +𝑓𝑐 + +1/𝑞1 − 𝑓𝑐 +𝑓𝐹 − 𝑓𝑐 +𝑓 ≤ 𝑓𝑐 +(𝑓 − 𝑓𝑐) +𝑓 > 𝑓c +The growth of the void volume fraction is defined as +where the growth of existing voids is given as: +𝑓 ̇ = 𝑓 ̇ +𝐺 + 𝑓 ̇ +𝑁 +and nucleation of new voids as: +in which 𝐴 is defined as +𝑝 , +𝑓 ̇ +𝐺 = (1 − 𝑓 )𝜀̇𝑘𝑘 +𝑓 ̇ +𝑁 = 𝐴𝜀̇𝑝 +𝐴 = +𝑓𝑁 +𝑆𝑁√2𝜋 +exp (− +( +𝜀𝑝 − 𝜀𝑁 +𝑆𝑁 +) +) +The Rc-Dc model is defined as the following: +The damage 𝐷 is given by +where 𝜀𝑝 is the equivalent plastic strain, +𝐷 = ∫ 𝜔1𝜔2𝑑𝜀𝑝 +𝜔1 = ( +1 − 𝛾𝜎𝑚 +) +is a triaxial stress weighting term and +𝜔2 = (2 − 𝐴𝐷)𝛽 +is a asymmetric strain weighting term. +In the above 𝜎𝑚 is the mean stress and +𝐴𝐷 = max ( +𝑆2 +𝑆3 +, +𝑆2 +𝑆1 +) +Fracture is initiated when the accumulation of damage is +𝐷𝑐 +> 1 +where 𝐷𝑐 is the a critical damage given by +𝐷𝑐 = 𝐷0(1 + 𝑏|∇𝐷|𝜆) +*MAT_120_RCDC +𝐹 = +𝐷 − 𝐷𝑐 +𝐷𝑠 +defines the degradations of the material by the Rc-Dc model. +The characteristic element length is used in the calculation of ∇𝐷. Calculation of this +factor is only done for element with smaller element length than this value. +*MAT_GENERAL_NONLINEAR_1DOF_DISCRETE_BEAM +This is Material Type 121. This is a very general spring and damper model. This beam +is based on the MAT_SPRING_GENERAL_NONLINEAR option and is a one- +dimensional version of the 6DOF_DISCRETE_BEAM above. The forces generated by +this model act along a line between the two connected nodal points. Additional +unloading options have been included. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +K +F +3 +4 +5 +6 +7 +8 +IUNLD +OFFSET +DAMPF +I +4 +F +5 +F +6 +7 +8 +Variable +LCIDT +LCIDTU +LCIDTD +LCIDTE +Type +I + Card 3 +1 +I +2 +Variable +UTFAIL +UCFAIL +Type +F +F +I +3 +IU +F +I +4 +5 +6 +7 +8 + VARIABLE +DESCRIPTION +MID +RO +K +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density, see also volume in *SECTION_BEAM definition. +Translational stiffness for unloading option 2.0. +VARIABLE +DESCRIPTION +IUNLD +Unloading option (Also see Figure M119-1): +EQ.0.0: Loading and unloading follow loading curve +EQ.1.0: Loading follows loading curve, unloading follows +unloading curve. The unloading curve ID if undefined +is taken as the loading curve. +EQ.2.0: Loading follows loading curve, unloading follows +unloading stiffness, K, to the unloading curve. The +loading and unloading curves may only intersect at the +origin of the axes. +EQ.3.0: Quadratic unloading from peak displacement value to +a permanent offset. +Offset to determine permanent set upon unloading if the +IUNLD = 3.0. The permanent sets in compression and tension are +equal to the product of this offset value and the maximum +compressive and tensile displacements, respectively. +Damping factor for stability. Values in the neighborhood of unity +are recommended. This damping factor is properly scaled to +eliminate time step size dependency. Also, it is active if and only +if the local stiffness is defined. +Load curve ID defining translational force resultant along the axis +versus relative translational displacement. If zero, no stiffness +related forces are generated for this degree of freedom. The +loading curves must be defined from the most negative +displacement to the most positive displacement. The force does +not need to increase monotonically for the loading curve. The +curves are extrapolated when the displacement range falls +outside the curve definition. +Load curve ID defining translational force resultant along the axis +versus relative translational displacement during unloading. The +force values defined by this curve must increase monotonically +from the most negative displacement to the most positive +displacement. For IUNLD = 1.0, the slope of this curve must +equal or exceed the loading curve for stability reasons. This is not +the case for IUNLD = 2.0. For loading and unloading to follow +the same path simply set LCIDTU = LCIDT. +OFFSET +DAMPF +LCIDT +LCIDTU +LCIDTD +Load curve ID defining translational damping force resultant +along the axis versus relative translational velocity. +LCIDTE +UTFAIL +UCFAIL +*MAT_GENERAL_NONLINEAR_1DOF_DISCRETE_BEAM +DESCRIPTION +Load curve ID defining translational damping force scale factor +versus relative displacement along the axis. +Optional, translational displacement at failure in tension. If zero, +failure in tension is not considered. +Optional, translational displacement at failure in compression. If +zero, failure in compression is not considered. +IU +Initial translational displacement along axis. +*MAT_122 +This is Material Type 122. This is Hill’s 1948 planar anisotropic material model with 3 R +values. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +E +F +3 +4 +PR +F +4 +Variable +R00 +R45 +R90 +LCID +F +2 +F +3 +Type +F + Card 3 +1 +Variable +AOPT +Type +F + Card 4 +1 +2 +3 +Variable +Type + Card 5 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +F +4 +4 +A1 +F +4 +D1 +F +5 +HR +F +5 +E0 +F +5 +5 +A2 +F +5 +D2 +F +6 +P1 +F +6 +7 +P2 +F +7 +8 +8 +6 +7 +8 +6 +A3 +F +6 +D3 +F +7 +8 +7 +8 +BETA +MID +RO +E +PR +HR +*MAT_HILL_3R +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus, E +Poisson’s ratio, ν +Hardening rule: +EQ.1.0: linear (default), +EQ.2.0: exponential. +EQ.3.0: load curve +P1 +Material parameter: +HR.EQ.1.0: Tangent modulus, +HR.EQ.2.0: k, strength coefficient for exponential hardening +P2 +Material parameter: +HR.EQ.1.0: Yield stress +HR.EQ.2.0: n, exponent +R00 +R45 +R90 +R00, Lankford parameter determined from experiments +R45, Lankford parameter determined from experiments +R90, Lankford parameter determined from experiments +LCID +load curve ID for the load curve hardening rule +E0 +𝜀0 for determining initial yield stress for exponential hardening. +(Default = 0.0) +AOPT +*MAT_122 +DESCRIPTION +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the shell ele- +ment normal by an angle BETA. +EQ.2.0: globally orthotropic with material axes determined by +the vector a defined below, as with *DEFINE_COOR- +DINATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +XP YP ZP +Coordinates of point p for AOPT = 1. +A1 A2 A3 +Components of vector a for AOPT = 2. +V1 V2 V3 +Components of vector v for AOPT = 3. +D1 D2 D3 +Components of vector d for AOPT = 2. +BETA +Μaterial angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA. +Remarks: +The calculated effective stress is stored in history variable #4. +*MAT_HILL_3R_3D +This is Material Type 122_3D. It combines orthotropic elastic behavior with Hill’s 1948 +anisotropic plasticity theory. Anisotropic plastic properties are given by 6 material +parameters, 𝐹, 𝐺, 𝐻, 𝐿, 𝑀, 𝑁 which are determined by experiments. This model is +implemented for solid elements. +This keyword can be written either as *MAT_HILL_3R_3D, or *MAT_122_3D. + Card 1 +1 +Variable +MID +Type +I + Card 2 +1 +2 +RO +F +2 +3 +EX +F +3 +Variable +GXY +GYZ +GXZ +Type +F +F +F +2 +HR +I +2 +3 +P1 +I/F +3 + Card 3 +Variable +Type +1 +N +F + Card 4 +1 +Variable +AOPT +Type +I +4 +EY +F +4 +F +F +4 +P2 +F +4 +5 +EZ +F +5 +G +F +5 +6 +7 +8 +PRXY +PRYZ +PRXZ +F +6 +H +F +6 +F +7 +L +F +7 +F +8 +M +F +8 +5 +6 +7 +Card 5 +Variable +1 +XP +Type +F + Card 6 +Variable +1 +V1 +Type +F +2 +YP +F +2 +V2 +F +3 +ZP +F +3 +V3 +F +4 +A1 +F +4 +D1 +F +5 +A2 +F +5 +D2 +F +6 +A3 +F +6 +D3 +F +7 +8 +7 +8 +BETA +F + VARIABLE +DESCRIPTION +MID +RO +EX, EY, EZ +Material identification ID, must be a unique number. +Mass density. +Young’s modulus in 𝑥, 𝑦, and 𝑧 directions, respectively. +Negative values indicate (positive) curve numbers, where +each curve is a function of temperature. +PRXY, PRYZ, PRXZ +Poisson’s ratio, 𝜈, in 𝑥𝑦, 𝑦𝑧 and 𝑥𝑧 directions, respectively. +Negative values indicate (positive) curve numbers, where +each curve is a function of temperature. +GXY, GYZ, GXZ +F, G, H, L, M, N +Shear modulus in 𝑥𝑦, 𝑦𝑧 and 𝑥𝑧 directions, respectively. +Negative values indicate (positive) curve numbers, where +each curve is a function of temperature. +Material constants in Hill’s 1948 yield criterion . + Negative values indicate (positive) curve +numbers, where each curve is a function of temperature. +HR +Hardening rule: +EQ.1: Stress-strain relationship is defined by load curve +or 2D-table ID with parameter P1. P2 is ignored. +EQ.2: Stress-strain relationship is defined by strength +coefficient K (P1) and strain hardening coefficient +n (P2), as in Swift’s exponential hardening equa- +tion: 𝜎yield = 𝑘(𝜀 + 0.01)𝑛. +VARIABLE +DESCRIPTION +P1 +Material parameter: +HR.EQ.1: Load curve or 2D-table ID defining stress- +strain curve. If 2D-table ID, the table gives +stress-strain curves for different temperatures. +HR.EQ.2: 𝑘, strength coefficient in 𝜎yield = 𝑘(𝜀 + 0.01)𝑛. +P2 +Material parameter: +HR.EQ.1: not used. +HR.EQ.2.0: 𝑛, the exponent in 𝜎𝑦𝑖𝑒𝑙𝑑 = 𝑘(𝜀 + 0.01)𝑛. +AOPT +Material axes option : +EQ.0.0: locally +orthotropic with material +axes +determined by element nodes 1, 2, and 4, as with +*DEFINE_COORDINATE_NODES. +EQ.1.0: locally +orthotropic with material +axes +determined by a point 𝐩 in space and the global +location of the element center; this is the a- +direction. This option is for solid elements only. +EQ.2.0: globally +orthotropic with material +axes +determined by the vectors 𝐚 and 𝐝, as with *DE- +FINE_COORDINATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element +normal by an angle, BETA, from a line in the +plane of the element defined by the cross prod- +uct of the vector 𝐯 with the element normal. +LT.0.0: the absolute value of AOPT is a coordinate +system ID number (CID on *DEFINE_COORDI- +NATE_NODES, *DEFINE_COORDINATE_SYS- +TEM or *DEFINE_COORDINATE_VECTOR). +XP, YP, ZP +Coordinates of point 𝐩 for AOPT = 1. +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3. +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2. +BETA +*MAT_122_3D +DESCRIPTION +Material angle in degrees for AOPT = 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA or *EL- +EMENT_SOLID_ORTHO. +Hill’s 1948 yield criterion: +Hill’s yield criterion is based on the assumptions that the material is orthotropic, that +hydrostatic stress does not affect yielding, and that there is no Bauschinger effect. +According to Hill, when the principal axes of anisotropy are the axes of reference, the +yield surface has the form +where the effective stress 𝜎̅̅̅̅̅ (stored as history variable #2) is given by +𝑓 = 𝜎̅̅̅̅̅(𝝈) − 𝜎yield(𝜀𝑝) = 0, +(𝐹 + 𝐺)𝜎̅̅̅̅̅ 2 = 𝐹(𝜎𝑦 − 𝜎𝑧) ++ 𝐺(𝜎𝑧 − 𝜎𝑥)2 + 𝐻(𝜎𝑥 − 𝜎𝑦) ++ 2𝐿𝜏𝑦𝑧 +2 + 2𝑀𝜏𝑧𝑥 +2 , +2 + 2𝑁𝜏𝑥𝑦 +and where 𝐹, 𝐺, 𝐻, 𝐿, 𝑀, 𝑁 are material parameters of the current state of anisotropy, +assuming three mutually orthogonal planes of symmetry at every point. The material 𝑧- +direction is here the reference direction. +Let 𝑋, 𝑌, 𝑍 be the tensile yield stresses in the principal directions of anisotropy, then +𝜎y0 +𝑋2 = +𝐺 + 𝐻 +𝐹 + 𝐺 +, +𝜎y0 +𝑌2 = +𝐻 + 𝐹 +𝐹 + 𝐺 +, +𝜎y0 +𝑍2 = 1, +where 𝜎y0 = 𝜎yield(0). 𝐹, 𝐺, 𝐻 are not uniquely determined, but the choice F+G = 1 +gives +𝐹 = +𝑍2 +( +𝑌2 + +𝑍2 − +𝑋2) , +𝐺 = +𝑍2 +𝑋2 + +( +𝑍2 − +𝑌2) , +𝐻 = +𝑍2 +( +𝑋2 + +𝑌2 − +𝑍2). +Material +F +G +H +L +M +N +AA5042 +0.3341 +0.5098 +0.3569 +1.5000 +1.5000 +1.8197 +Table M122-1. +NUMISHEET 2011. + AA5042 material constants (Hill’s 1948 yield) - BM1 +If 𝑅𝑥𝑦 , 𝑆𝑧𝑥 , 𝑇𝑥𝑦 are the yield stresses in shear with respect to the principal axes of +anisotropy, then +𝐿 = +𝑍2 +2 , +2𝑅𝑥𝑦 +𝑀 = +𝑍2 +2 , +2𝑆𝑧𝑥 +𝑁 = +𝑍2 +2 . +2𝑇𝑥𝑦 +If 𝐹 = 𝐺 = 𝐻, and, 𝐿 = 𝑀 = 𝑁 = 3𝐹, the Hill criterion reduces to the Von-Mises +criterion. +The strain hardening in this model can either defined by the load curve or by Swift’s +exponential hardening equation: 𝜎yield = 𝑘(𝜀 + 0.01)𝑛. +Validation and application: +1. This material model is suitable for metal forming application using solid +elements to account for anisotropic plasticity. NUMISHEET conferences have +provided material constants of Hill’s 1948 yield for many commonly used ma- +terials. In this example, experimental results from benchmark 1 (BM1, AA5042) +of the NUMISHEET 2011 are used to validate an equal-biaxial tension and two +uniaxial tensile results in two different directions (rolling and 90°) on a single +solid element. +As shown in Figure M122-1(top left), under the constraints imposed, a single +element of solid type 2 is pulled in uniaxial tension in the 𝑥-direction. The +resulting hardening curve is compared with experimental data provided (top +right). Similarly, the element is pulled in uniaxial tension in the Y-direction +under the constraints shown in Figure M122-1(middle left). The resulting hard- +ening curve is compared with experimental data (middle right). In Figure +M122-1(bottom left), the element is pulled in both 𝑥- and 𝑦-directions equally +under the constraints shown, and the resulting hardening curve is compared +with experimental data (bottom right). All computed results are satisfactory. +The material constants used for the simulation are provided in Table M122-1. +In addition, an element of type 1 is subjected to a shear test with a composite +material, courtesy of CYBERNET SYSTEMS CO., LTD. Results compare well +with the experiments, as shown in Figure M122-2. +In real world application, the six material parameters required can be calibrated +with nonlinear regression analysis (such as those available through LS-OPT) +through a series of tensile tests in three orthogonal directions and three shear +tests in three orthogonal planes. +2. This material model can also be applied in multi-scale simulation of fiberglass +and laminated materials, according to CYBERNET SYSTEMS CO., LTD. The +elastic coefficients can be calibrated analytically by a homogenization method +with tensile tests in the three orthogonal directions and three pure shear tests in +the three orthogonal planes. +Revision information: +The material model is available in explicit dynamics in both SMP and MPP starting in +Revision 86100, and is available in implicit dynamics in both SMP and MPP starting in +Revision 104178. It also supports temperature dependent Young’s/shear modulus, +Poisson ratios, and Hill parameters. +0= +*MAT_HILL_3R_3D +Rolling direction (0 deg.) tensile pull +ux +Fy +0= +) +( +500.0 +400.0 +300.0 +200.0 +100.0 +0.0 +) +( +500.0 +400.0 +300.0 +200.0 +100.0 +0.0 +) +( +500.0 +400.0 +300.0 +200.0 +100.0 +0.0 +Fz +0= +Fz +0= +uy +ux +uy +Experiment +LS-DYNA +0.0 0.03 +0.08 +0.13 +0.18 +True strain +90 deg. tensile pull +Experiment +LS-DYNA +0.0 0.03 +0.08 +0.13 +0.18 +True strain +Equi-biaxial test +Experiment +LS-DYNA +0.0 0.03 +0.08 +0.13 +0.18 +True strain +Fy +0= +Figure M122-1. Validation with experiments - BM1 NUMISHEET 2011 +ux +35.0 +30.0 +25.0 +20.0 +10.0 +) +( +0.0 +0.0 +XY shear test +Experiment +LS-DYNA +0.01 +0.02 +0.03 +True strain +Figure M122-2. Shear result validated with test results (Courtesy of +CYBERNET SYSTEMS CO., LTD.) +*MAT_MODIFIED_PIECEWISE_LINEAR_PLASTICITY_{OPTION} +This is Material Type 123, which is an elasto-plastic material supporting an arbitrary +stress versus strain curve as well as arbitrary strain rate dependency. This model is +available for shell and solid elements. Another model, MAT_PIECEWISE_LINEAR_ +PLASTICITY, is similar but lacks the enhanced failure criteria. Failure is based on +effective plastic strain, plastic thinning, the major principal in plane strain component, +or a minimum time step size. See the discussion under the model description for MAT_ +PIECEWISE_LINEAR_PLASTICITY if more information is desired. +Available options include: + +RATE +RTCL +STOCHASTIC (for shells only) +The “RATE” option is used to account for rate dependence of plastic thinning failure. +The “RTCL” option is used to activate RTCL damage. One additional card is needed +with either option. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +6 +7 +8 +SIGY +ETAN +FAIL +TDEL +F +F +F +Default +none +none +none +none +none +0.0 +10.E+20 + Card 2 +Variable +Type +Default +1 +C +F +0 +2 +P +F +0 +3 +4 +5 +6 +7 +LCSS +LCSR +VP +EPSTHIN +EPSMAJ NUMINT +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EPS1 +EPS2 +EPS3 +EPS4 +EPS5 +EPS6 +EPS7 +EPS8 +Type +Default +F +0 + Card 4 +1 +F +0 +2 +F +0 +3 +F +0 +4 +F +0 +5 +F +0 +6 +F +0 +7 +F +0 +8 +Variable +ES1 +ES2 +ES3 +ES4 +ES5 +ES6 +ES7 +ES8 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +Card 5 is required if and only if either the RATE or RTCL option is active. + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCTSRF +EPS0 +TRIAX +Type +Default +I +0 +F +0 +F +0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +SIGY +Yield stress. +*MAT_MODIFIED_PIECEWISE_LINEAR_PLASTICITY +DESCRIPTION +ETAN +Tangent modulus, ignored if (LCSS.GT.0) is defined. +FAIL +Failure flag. +LT.0.0: User defined failure subroutine, matusr_24 in dyn21.F, +is called to determine failure +EQ.0.0: Failure is not considered. This option is recommended +if failure is not of interest since many calculations will +be saved. +GT.0.0: Plastic strain to failure. When the plastic strain reaches +this value, the element is deleted from the calculation. +TDEL +Minimum time step size for automatic element deletion. +C +P +Strain rate parameter, C, see formula below. +Strain rate parameter, P, see formula below. +LCSS +Load curve ID or Table ID. +Load Curve. When LCSS is a Load curve ID, it is taken as +defining effective stress versus effective plastic strain. If defined +EPS1 - EPS8 and ES1 - ES8 are ignored. +Tabular Data. The table ID defines for each strain rate value a +load curve ID giving the stress versus effective plastic strain for +that rate, See Figure M24-1. When the strain rate falls below the +minimum value, the stress versus effective plastic strain curve for +the lowest value of strain rate is used. Likewise, when the strain +rate exceeds the maximum value the stress versus effective plastic +strain curve for the highest value of strain rate is used. The strain +rate parameters: C and P, the curve ID, LCSR, EPS1 - EPS8, and +ES1 - ES8 are ignored if a Table ID is defined. +Logarithmically Defined Tables. If the first stress-strain curve in +the table corresponds to a negative strain rate, LS-DYNA assumes +that the natural logarithm of the strain rate value is used for all +stress-strain curves. Since the tables are internally discretized to +equally space the points, natural logarithms are necessary, for +example, if the curves correspond to rates from 10−4 to 104. +Computing natural logarithms can substantially increase the +computational time on certain computer architectures. +LCSR +Load curve ID defining strain rate scaling effect on yield stress. +VARIABLE +DESCRIPTION +VP +Formulation for rate effects: +EQ.0.0: Scale yield stress (default), +EQ.1.0: Viscoplastic formulation (recommended). +EPSTHIN +Thinning strain at failure. This number should be given as a +positive number. +EPSMAJ +Major in plane strain at failure. +NUMINT +EPS1 - EPS8 +LT.0: EPSMAJ = |EPSMAJ| and filtering is activated. The last +twelve values of the major strain is stored at each integra- +tion point and the average value is used to determine +failure. +Number of integration points which must fail before the element +is deleted. (If zero, all points must fail.) For fully integrated shell +formulations, each of the 4 × NIP integration points are counted +individually in determining a total for failed integration points. +NIP is the number of through-thickness integration points. As +NUMINT approaches the total number of integration points (NIP +for under integrated shells, 4*NIP for fully integrated shells), the +chance of instability increases. +LT.0.0: |NUMINT| is percentage of integration points/layers +which must fail before shell element fails. For fully in- +tegrated shells, a methodology is used where a layer +fails if one integration point fails and then the given +percentage of layers must fail before the element fails. +Only available for shells. +Effective plastic strain values (optional if SIGY is defined). At +least 2 points should be defined. The first point must be zero +corresponding to the initial yield stress. WARNING: If the first +point is nonzero the yield stress is extrapolated to determine the +initial yield. If this option is used SIGY and ETAN are ignored +and may be input as zero. +ES1 - ES8 +Corresponding yield stress values to EPS1 - EPS8. +LCTSRF +Load curve that defines the thinning strain at failure as a function +of the plastic strain rate. +*MAT_MODIFIED_PIECEWISE_LINEAR_PLASTICITY +DESCRIPTION +EPS0 +EPS0 parameter for RTCL damage. +EQ.0.0: (default) RTCL damage is inactive. +GT.0.0: RTCL damage is active +TRIAX +RTCL damage triaxiality limit. +EQ.0.0: (default) No limit. +GT.0.0: Damage does not accumulate when triaxiality exceeds +TRIAX. +Remarks: +Optional RTCL damage is used to fail elements when the damage function exceeds 1.0. +During each solution cycle, if the plastic strain increment is greater than zero, an +increment of RTCL damage is calculated by +𝛥𝑓damage = +𝜀0 +𝑓 ( +𝜎𝐻 +𝜎̅̅̅̅̅ +𝑑𝜀̅𝑝 +) +RTCL +where +and, +𝑓 ( +𝜎𝐻 +𝜎̅̅̅̅̅ +) += +RTCL +⎧0 +{{ +{{{{ +{{ +⎨ +{{ +{{{ +{{{ +⎩ +1 + +𝜎𝐻 +𝜎̅̅̅̅̅ +𝜎𝐻 +𝜎̅̅̅̅̅ +√12 − 27( ++ √12 − 27( +1.65 +exp ( +3𝜎𝐻 +2𝜎̅̅̅̅̅ +) +𝜎𝐻 +𝜎̅̅̅̅̅ +𝜎𝐻 +𝜎̅̅̅̅̅ +𝜎𝐻 +𝜎̅̅̅̅̅ +≤ − +) +) +< +𝜎𝐻 +𝜎̅̅̅̅̅ +< +𝜎𝐻 +𝜎̅̅̅̅̅ +≥ +𝜀0 = uniaxial fracture strain / critical damage value +𝜎𝐻 = hydrostatic stress +𝜎̅̅̅̅̅ = effective stress +𝑑𝜀̅𝑝 = effective plastic strain increment +The increments are summed through time and the element is deleted when 𝑓damage ≥ +1.0. For 0.0 < 𝑓damage < 1.0, + the element strength will not be degraded. +The value of 𝑓damage is stored as history variable #9 and can be fringe plotted from d3plot +files if the number of extra history variables requested is ≥ 9 on *DATABASE_EX- +TENT_BINARY. +The optional TRIAX parameter can be used to prevent excessive RTCL damage growth +and element erosion for badly shaped elements that might show unrealistically high +values for the triaxiality. The triaxiality, +𝜎𝐻 +𝜎̅̅̅̅̅ , is stored as history variable #11. +The EPSMAJ parameter is compared to the major principal strain in the following +senses: +• For shells it is the maximum eigenvalue of the in-plane strain tensor that is +incremented by the strain increments. +• For solid elements it is calculated as the maximum eigenvalue to the logarithmic +strain tensor +𝛆 = +ln(𝐅T𝐅), +where 𝐅 is the global deformation gradient. In sum, both element types use a +natural strain measure for determining failure, the major strain calculated in this +way is output as history variable #7. +To get an idea about the probability of failure, an indicator 𝐷 is computed internally: +𝐷 = max ( +𝜀̅𝑝 +FAIL +, +−𝜀3 +EPSTHIN +, +𝜀𝐼 +EPSMAJ +) +and stored as history variable #10. 𝐷 ranges from 0 (intact) to 1 (failed). 𝜀̅𝑝, −𝜀3, and 𝜀𝐼 +are current values of effective plastic strain, thinning strain, and major in plane strain. +This instability measure, including the RTCL damage, can also be retrieved from +requesting material histories +*DEFINE_MATERIAL_HISTORIES Properties +Label +Attributes +Description +Instability +Plastic Strain Rate +- +- +- +- +- +- +- +- +Failure indicator max(𝐷, 𝑓damage) +𝑝 +Effective plastic strain rate 𝜀̇eff +For implicit calculations on this material involving severe nonlinear hardening the +radial return method may result in inaccurate stress-strain response. Setting IACC = 1 +on *CONTROL_ACCURACY activates a fully iterative plasticity algorithm, which will +remedy this. This is not to be confused with the MITER flag on *CONTROL_SHELL, +which governs the treatment of the plane stress assumption for shell elements. If any +failure model is applied with this option, incident failure will initiate damage, and the +stress will continuously degrade to zero before erosion for a deformation of 1% plastic +strain. So for instance, if the failure strain is FAIL = 0.05, then the element is eroded +when 𝜀̅𝑝 = 0.06 and the material goes from intact to completely damaged between +𝜀̅𝑝 = 0.05 and 𝜀̅𝑝 = 0.06. The reason is to enhance implicit performance by maintaining +continuity in the internal forces. +*MAT_PLASTICITY_COMPRESSION_TENSION +This is Material Type 124. An isotropic elastic-plastic material where unique yield +stress versus plastic strain curves can be defined for compression and tension. Also, +failure can occur based on a plastic strain or a minimum time step size. Rate effects on +the yield stress are modeled either by using the Cowper-Symonds strain rate model or +by using two load curves that scale the yield stress values in compression and tension, +respectively. Material rate effects, which are independent of the plasticity model, are +based on a 6-term Prony series Maxwell mode that generates an additional stress tensor. +The viscous stress tensor is superimposed on the stress tensor generated by the +plasticity. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +Default +none +none +none +none + Card 2 +1 +2 +3 +4 +5 +C +F +0 +5 +6 +P +F +0 +6 +Variable +LCIDC +LCIDT +LCSRC +LCSRT +SRFLAG +LCFAIL +Type +Default + Card 3 +Variable +Type +Default +I +0 +1 +PC +F +0 +I +0 +2 +PT +F +0 +I +0 +3 +I +0 +4 +F +0 +5 +I +0 +6 +PCUTC +PCUTT +PCUTF +F +0 +F +0 +F +0 +7 +8 +FAIL +TDEL +F +10.E+20 +7 +EC +F +none +7 +F +0 +8 +RPCT +F +0 +3 +4 +5 +6 +7 +8 +*MAT_124 + Card 4 +Variable +Type +1 +K +F +Viscoelastic Constant Cards. Up to 6 cards may be input. A keyword card (with a +“*” in column 1) terminates this input if less than 6 cards are used. + Card 5 +Variable +Type +1 +Gi +F + VARIABLE +MID +RO +E +PR +C +P +2 +3 +4 +5 +6 +7 +8 +BETAi +F +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +Strain rate parameter, 𝐶, see formula below. +Strain rate parameter, 𝑃, see formula below. +FAIL +Failure flag. +LT.0.0: User defined failure subroutine, matusr_24 in dyn21.F, +is called to determine failure +EQ.0.0: Failure is not considered. This option is recommended +if failure is not of interest since many calculations will +be saved. +GT.0.0: Plastic strain to failure. When the plastic strain reaches +this value, the element is deleted from the calculation. +TDEL +Minimum time step size for automatic deletion of shell elements. +VARIABLE +LCIDC +LCIDT +LCSRC +LCSRT +DESCRIPTION +Load curve ID defining effective stress versus effective plastic +strain in compression. Enter positive yield stress and plastic +strain values when defining this curve. +Load curve ID defining effective stress versus effective plastic +strain in tension. Enter positive yield stress and plastic strain +values when defining this curve. +Optional load curve ID defining strain rate scaling factor on yield +stress versus strain rate when the material is in compression. +Optional load curve ID defining strain rate scaling factor on yield +stress versus strain rate when the material is in tension. +SRFLAG +Formulation for rate effects: +EQ.0.0: Total strain rate, +EQ.1.0: Deviatoric strain rate. +EQ.2.0: Plastic strain rate (viscoplastic). +LCFAIL +EC +RPCT +PC +PT +Load curve ID defining failure strain versus strain rate. See +Remarks for additional information. +Optional Young’s modulus for compression, > 0. +Fraction of PT and PC, used to define mean stress at which +Young’s modulus is E and EC, respectively. Young’s modulus is +E when mean stress > RPCT × PT, and EC when mean stress < - +RPCT × PC. If the mean stress falls between –RPCT × PC and +RPCT × PT, a linearly interpolated value is used. +Compressive mean stress (pressure) at which the yield stress +follows load curve ID, LCIDC. If the pressure falls between PC +and PT a weighted average of the two load curves is used. Both +PC and PT should be entered as positive values. +Tensile mean stress at which the yield stress follows load curve +ID, LCIDT. +PCUTC +*MAT_PLASTICITY_COMPRESSION_TENSION +DESCRIPTION +Pressure cut-off in compression (PCUTC must be greater than or +equal to zero). PCUTC (and PCUTT) apply only to element types +that use a 3D stress update, e.g., solids, tshell formulations 3 and +5, and SPH. When the pressure cut-off is reached the deviatoric +stress tensor is set to zero and the pressure remains at its +compressive value. Like the yield stress, PCUTC is scaled to +account for rate effects. +PCUTT +Pressure cut-off in tension (PCUTT must be less than or equal to +zero). When the pressure cut-off is reached the deviatoric stress +tensor and tensile pressure is set to zero. Like the yield stress, +PCUTT is scaled to account for rate effects. +PCUTF +Pressure cut-off flag activation. +EQ.0.0: Inactive, +EQ.1.0: Active. +K +Gi +Optional bulk modulus for the viscoelastic material. If nonzero a +Kelvin type behavior will be obtained. Generally, 𝐾 is set to zero. +Optional shear relaxation modulus for the ith term +BETAi +Optional shear decay constant for the ith term +Remarks: +The stress strain behavior follows a different curve in compression than it does in +tension. Tension is determined by the sign of the mean stress where a positive mean +stress (i.e., a negative pressure) is indicative of tension. Two curves must be defined +giving the yield stress versus effective plastic strain for both the tension and +compression regimes. +Mean stress is an invariant which can be expressed as (𝜎𝑥 + 𝜎𝑦 + 𝜎𝑧)/3. PC and PT +define a range of mean stress values within which interpolation is done between the +tensile yield surface and compressive yield surface. PC and PT are not true material +properties but are just a numerical convenience so that the transition from one yield +surface to the other is not abrupt as the sign of the mean stress changes. Both PC and +PT are input as positive values as it is implied that PC is a compressive mean stress +value and PT is tensile mean stress value. +Strain rate may be accounted for using the Cowper and Symonds model which scales +the yield stress with the factor: +where 𝜀̇ is the strain rate, +1 + [ +𝑝⁄ +𝜀̇ +] +𝜀̇ = √𝜀̇𝑖𝑗𝜀̇𝑖𝑗. +The LCFAIL field is only applicable when at least one of the following four conditions +are met: +1. SRFLAG = 2 +2. LCSRC is nonzero +3. LCSRT is nonzero +4. Gi, BETAi values are provided. +*MAT_KINEMATIC_HARDENING_TRANSVERSELY_ANISOTROPIC_{OPTION} +This is Material Type 125. This material model combines Yoshida & Uemori’s non- +linear kinematic hardening rule with material type 37. Yoshida & Uemori’s theory uses +two surfaces to describe the hardening rule: the yield surface and the bounding surface. +In the forming process, the yield surface does not change in size, but its center translates +with deformation; the bounding surface changes both in size and location. This model +also allows the change of Young’s modulus as a function of effective plastic strain as +proposed by Yoshida & Uemori [2002]. This material type is available for shells, thick +shells and solid elements. +Available options include: + +NLP +The NLP option estimates necking failure using the Formability Index (F.I.), which +accounts for the non-linear strain paths seen in metal forming applications . Specify IFLD in card #3 when using this option, also see the example under +the remarks. Since the NLP option also works under linear strain path, it is +recommended to be used as the default failure criterion in metal forming. The NLP +option is also available in *MAT_036, *MAT_037, and *MAT_226. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +R +F +I +6 +7 +8 +HLCID +OPT +Default +none +none +none +none +none +none + Card 2 +Variable +1 +CB +Type +F +2 +Y +F +3 +SC1 +F +4 +K +F +5 +RSAT +F +6 +SB +F +I +0 +7 +H +F +8 +SC2 +F +Default +none +none +none +none +none +none +none +0.0 +Card 3 +Variable +1 +EA +2 +3 +COE +IOPT +Type +F +F +Default +none +none +I +0 +4 +C1 +F +5 +C2 +F +6 +7 +8 +IFLD +I +none +none +none + VARIABLE +DESCRIPTION +MID +RO +E +PR +R +HLCID +OPT +CB +Y +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s Modulus +Poisson’s ratio +Anisotropic hardening parameter +Load curve ID in keyword *DEFINE_CURVE, where true strain +and true stress relationship is characterized. This curve is used in +conjunction with variable OPT, and not to be referenced or used +in other keywords. +The use of this parameter is not recommended. +Error calculation flag. When OPT = 2, LS-DYNA will perform +error calculation based on the true stress-strain curve from +uniaxial tension, specified by HLCID. The corrections will be +made to the cyclic load curve, both in the loading and unloading +portions. Since, in some cases where loading is more complex, +the accumulated plastic strain could be large (say more than 30%), +the input uniaxial stress-strain curve must have enough strain +range to cover the maximum expected plastic strain. Note this +variable must be set to a value of “2” if HLCID is specified and +stress-strain curve is used. +The default value of “0” is recommended. +The uppercase 𝐵 defined in Yoshida & Uemori’s equations. +Hardening parameter appearing +equations. +in Yoshida & Uemori’s +*MAT_KINEMATIC_HARDENING_TRANSVERSELY_ANISOTROPIC +DESCRIPTION +SC1 +K +RSAT +SB +H +SC2 +EA +COE +The lowercase 𝑐 defined in the following equations, and 𝐶1 as in +the remarks section. +Hardening parameter appearing +equations. +in Yoshida & Uemori’s +Hardening parameter appearing +equations. +in Yoshida & Uemori’s +The lowercase 𝑏 appearing in Yoshida & Uemori’s equations. +Anisotropic parameter +stagnation. +associated with work-hardening +The lowercase 𝑐 defined in the following equations, and 𝐶2 as in +the remarks section. If SC2 = 0.0, left blank, or SC2 = SC1, then it +turns into the basic model. +Variable controlling the change of Young’s modulus, 𝐸𝐴 in the +following equations. +Variable controlling the change of Young’s modulus, 𝜁 in the +following equations. +IOPT +Modified kinematic hardening rule flag: +EQ.0: Original Yoshida & Uemori formulation, +EQ.1: Modified formulation. Define C1, C2 below. +C1, C2 +Constants used to modify R: +𝑅 = RSAT × [(𝐶1 + 𝜀̅𝑝)𝑐2 − 𝐶1 +𝑐2] +IFLD +ID of a load curve defining Forming Limit Diagram (FLD) under +linear strain paths. In the load curve, abscissas represent minor +strains while ordinates represent major strains. Define only +when the option NLP is used. See the example in the remarks +section. +The Yoshida & Uemori’s kinematic hardening model: +According to F. Yoshida and T. Uemori’s paper titled “A model of large-strain cyclic +plasticity describing the Bauschinger effect and work hardening stagnation” in 2002 +International Journal of Plasticity 18, 661-686, and referring to Figure M125-1, +𝛼∗ = 𝛼 − 𝛽 +𝛼∗ = 𝑐 [( +) (𝜎 − 𝛼) − √ +𝛼∗ +𝛼∗] 𝜀̅𝑝 +𝑎 = 𝐵 + 𝑅 − 𝑌 +The change of size and location for the bounding surface is defined as, referring to +Figure M125-2, +𝑅̇ = 𝑘(𝑅sat − 𝑅)𝜀̅ +𝛽′ +𝑏𝐷 − 𝛽′𝜀̅ += 𝑘( +̇𝑝, +̇𝑝) +In Yoshida & Uemori’s model, there is work-hardening stagnation in the unloading +process, and it is described as, +𝜎bound = 𝐵 + 𝑅 + 𝛽 +𝑔𝜎(𝜎 ′, 𝑞′, 𝑟′) = +(𝜎 ′ − 𝑞′): (𝜎 ′ − 𝑞′) − 𝑟2 +𝑞′ += 𝜇(𝛽′ − 𝑞′) +𝑟 = ℎΓ +3(𝛽′ − 𝑞′): 𝛽′ +2𝑟 +Γ = +The change in Young’s modulus is defined as a function of effective strain, +𝐸 = 𝐸0 − (𝐸0 − 𝐸𝐴)[1 − exp(−𝜁 𝜀̅𝑝)] +Strain hardening saturation: +in NUMISHEET 2008 proceedings, 137-142, 2008, +Further improvements in the original Yoshida & Uemori’s model, as described in a +paper “Determination of Nonlinear Isotropic/Kinematic Hardening Constitutive Parameter for +AHSS using Tension and Compression Tests”, by Ming F. Shi, Xinhai Zhu, Cedric Xia, +Thomas Stoughton, +included +modifications to allow working hardening in large strain deformation region, avoiding +the problem of earlier saturation, especially for Advanced High Strength Steel (AHSS). +These types of steels exhibit continuous strain hardening behavior and a non-saturated +isotropic hardening function. As described in the paper, the evolution equation for R (a +part of the current radius of the bounding surface in deviatoric stress space), as is with +the saturation type of isotropic hardening rule proposed in the original Yoshida & +Uemori model, +𝑅̇ = 𝑚(𝑅sat − 𝑅)𝑝̇ +is modified as, +𝑅 = RSAT × [(𝐶1 + 𝜀̅𝑝)𝑐2 − 𝐶1 +𝑐2] +For saturation type of isotropic hardening rule, set IOPT = 0, applicable to most of +Aluminum sheet materials. In addition, the paper provides detailed variables used for +this material model for DDQ, HSLA, DP600, DP780 and DP980 materials. Since the +symbols used in the paper are different from what are used here, the following table +provides a reference between symbols used in the paper and variables here in this +keyword: +B +CB +Y +Y +C +SC1 +m +K +K +Rsat +b +SB +h +H +e0 +C1 +N +C2 +Using the modified formulation and the material properties provided by the paper, the +predicted and tested results compared very well both in a full cycle tension and +compression test and in a pre-strained tension and compression test, according to the +paper. +A Failure Criterion for Nonlinear Strain Paths (NLP): +The NLP failure criterion and corresponding post processing procedures are described +in the entries for *MAT_036 and *MAT_037. The history variables for every element +stored in d3plot files include: +1. Formability Index (F.I.): #1 +2. Strain ratio (in-plane minor strain/major strain): #2 +3. Effective strain from the planar isotropic assumption: #3 +The entire time history can be plotted using Post/History menu in LS-PrePost v4.0. To +enable the output of these history variables to the d3plot files, NEIPS on the *DATA- +BASE_EXTENT_BINARY card must be set to at least 3. When plotting the formability +index, first select the history var #1 from the Misc in the FriComp menu. The pull-down +menu under FriComp can be used to select minimum value ‘Min’ for necking failure +determination (refer to Tharrett and Stoughton’s paper in 2003 SAE 2003-01-1157). In +FriRang, the option None is to be selected in the pull-down menu next to Avg. Lastly, set +the simulation result to the last state in the animation tool bar. The index value ranges +from 0.0 to 1.5. The non-linear forming limit is reached when the index reaches 1.0. +An Example of the NLP Option: +A partial keyword example is listed below when the option NLP is used. The +traditional Forming Limit Diagram (FLD) which governs the linear strain paths only is +defined by load curve ID 321. +*MAT_KINEMATIC_HARDENING_TRANSVERSELY_ANISOTROPIC_NLP +$# mid ro e pr r hclid opt + 1 7.83E-9 2.07E+5 0.3 1.035 +$# cb y sc k rsat sb h + 422.8 304.2 398.5 28.0 702.7 136.9 0.91 +$# ea coe iopt c1 c2 IFLD + 0.0 0.0 1 0.0065 0.545 321 +*DEFINE_CURVE +$ traditional FLD data (major vs. minor) +321 +-0.357,0.596 +⋮ +⋮ +-0.020,0.260 + 0.000,0.239 + 0.010,0.244 + 0.020,0.249 +⋮ +⋮ + 0.239,0.354 + 0.247,0.356 + 0.262,0.361 + 0.372,0.361 +*END +Application results: +Application of the modified Yoshida & Uemori’s hardening rule in the metal forming +industry has shown significant advantage in springback prediction accuracy, especially +for AHSS type of sheet materials. As shown in Figure M125-3 (left), predicted +springback shape of an automotive shotgun (also called: upper load path/beam) using +*MAT_125 is compared with experimental measurements on a DP780 material. +Prediction accuracy achieved over 92% with *MAT_125 while about 61% correlation is +found with *MAT_037 (Figure M125-3 right), a remarkable improvement. +In another example, NUMISHEET 2011 BM4 is used to demonstrate the application of +the Young’s modulus variations as a function of effective strain in prediction of +springback. The sheet blank is a DP780 material with an initial thickness of 1.4mm. The +simulation process is shown (Figure M125-4) as pre-straining (to 8%), springback, +trimming, forming and springback. Young’s modulus variations with effective strains +are accounted for by curve fitting the provided experimental data to obtain the +variables EA and COE, Figure M125-5. Referring to Figures M125-6 and M125-7, final +springback shapes of the cross sectional view are compared with measurement +provided, along with benchmark results from software X and Y. In addition, +springback with no pre-straining is also conducted and correlated, shown in the same +figures. Furthermore, hysteretic plasticity with a full cycle tension and compression +simulation is done on one single shell element and the result is superimposed with +experimental date, in Figure M125-8. +To improve convergence and for a faster simulation time, it is recommended that +*CONTROL_IMPLICIT_FORMING type ‘1’ be used when conducting a springback +simulation. +About SC1 and SC2: +In F. Yoshida and T. Uemori’s 2002 paper, the effect of variables SC1 and SC2 were +discussed. According to the paper, variables SC1 and SC2 are used to describe the +forward and reverse deformations of the cyclic plasticity curve, respectively. It allows +for a more rapid change of work hardening rate in the vicinity of the initial yielding +(~0.5% equivalent plastic strain), in the form of the following equations: +SC = +⎧ +{{ +⎨ +{{ +⎩ +SC1 +max(𝛼̅∗) < 𝐵 − 𝑌 +SC2 +otherwise +where max(𝛼̅∗) is the maximum value of 𝛼̅∗, and, +𝛼̅∗ = √ +𝛼∗: 𝛼∗ +As shown in Figure M125-9 from Yoshida & Uemori’s original paper, the effect of a +curve fitting is shown for a high strength steel (SPFC) using both SC1 and SC2, which +fits much better than the fitting using only SC1. In addition, in Figure M125-10, a much +better fitting is demonstrated with SC1 and SC2 than with SC1 only for a DP980 +material. +Inclusion of shell normal stress: +When *LOAD_SURFACE_STRESS is used in the input deck together with *MAT_125, +normal stresses (either from sliding contact or applied pressure) are accounted for +during the simulation. The negative local 𝑧-stresses (select z-stress under FCOMP → +Stress and select local under FCOMP in LS-PrePost) caused by the sliding contact or +applied pressure can be viewed from d3plot files after Revision 97158. It is found in +some cases this inclusion can improve forming simulation accuracy. +Revision information: +The variables HLCID, OPT, IOPT, C1, and C2 are available starting in Revision 46217. +The variables SC1 and SC2 are available starting in Revision 74884. The option NLP is +available in explicit dynamic analysis starting in Revision 95594. Normal stresses +inclusion is available starting in Revision 97158. Later Revisions include various +improvements and should be used. +Bounding surface +Dp +Yield surface +* +B+R +Figure M125-1. Schematic illustration of the two-surface model is the original +center of the yield surface, 𝛼∗ is the current center for the yield surface; 𝛼 is the +center of the bounding surface. 𝛽 represents the relative position of the centers +of the two surfaces. Y is the size of the yield surface and is constant +throughout the deformation process. B+R represents the size of the bounding +surface, with R being associated with isotropic hardening. Reproduced from the +original Yoshida and Uemori’s paper. +Bounding surface F +β' +q' +gσ +gσ +β' +q'o +β' +q' +(a) when R = 0 +(b) when R > 0 +Figure M125-2. Change in bounding surface (reproduced from the original +Yoshida and Uemori’s paper). +Red: measured +Black: simulation +92.51% of sampled points +within 1mm deviation +61.78% of sampled points +within 1mm deviation +Max. 6.63mm +Max. 2.42mm +*MAT_125 +*MAT_037 +Figure M125-3. Comparison of springback prediction on the A/S P load beam +(reproduced from an original color contour map courtesy of Chrysler LLC and United +States Steel Corporation). +Blanking +Pre-straining +Springback +Trimming +Forming +Forming complete +Springback + Figure M125-4. NUMISHEET 2011 Benchmark #4 simulation procedure. +) +( +' +200 +195 +190 +185 +180 +175 + 170 + 165 +Young's Modulus Evolution +Fitted for LS-DYNA +Test +0.02 +0.04 +0.06 +0.08 +0.10 +0.12 +Equivalent plastic strain +Figure M125-5. Curve fitting with coefficients: EA = 1.668E+05; COE = 95.0. +Springback Profile: No Prestrain +Springback Profile: 8% Prestrain + 70 + 60 + 50 + 40 + 30 + 20 + 10 + 0 +Test +LS-DYNA +Software X + 0 + 20 + 40 + 60 + 80 + 100 + 120 + 140 +mm + 70 + 60 + 50 + 40 + 30 + 20 + 10 + 0 +Test +LS-DYNA +Software X + 0 + 20 + 40 + 60 +mm + 80 + 100 + 120 +Figure M125-6. Comparison of springback profile with software X: 0% (left) +and 8% prestrain (right) +Springback Profile: No Prestrain +Springback Profile: 8% Prestrain + 70 + 60 + 50 + 40 + 30 + 20 + 10 + 0 +Test +LS-DYNA +Software Y + 0 + 20 + 40 + 60 + 80 + 100 + 120 + 140 +mm + 70 + 60 + 50 + 40 + 30 + 20 + 10 + 0 +Test +LS-DYNA +Software Y + 0 + 20 + 40 + 60 +mm + 80 + 100 + 120 +Figure M125-7. Comparison of springback profile with software Y: 0% (left) +and 8% prestrain(right) +Uni-axial tension +Uni-axial tension +Cyclic test +M125 result +) +( +800 +400 +-400 +-800 +Unstrained +Uni-axial compression +0.04 +0.08 +True strain +Figure M125-8. Cyclic plasticity verification on one element. +) +( +800 +700 +600 +500 +400 +300 +200 +100 +Experiment +Basic model(SC1=200) +Modified model (SC1=2000, SC2=200 in Eq. (1) +0.01 +0.02 +0.03 +0.04 +0.05 +0.06 +True strain +Figure M125-9. Effect of SC1 and SC2 (reproduced from the original Yoshida & +Uemori’s paper). +1200 +900 +600 +300 +-300 +-600 +-900 +-1200 +1200 +900 +600 +300 +-300 +-600 +-900 +-1200 +Experimental result +Curve fitting result +SC1 + SC2 +-0.03 +0.03 +SC1 only +-0.03 +0.03 +Figure M125-10. Material curve fitting comparison (reproduced from an original +color slide courtesy of CYBERNET SYSTEMS CO., LTD.). +*MAT_MODIFIED_HONEYCOMB +This is Material Type 126. The major use of this material model is for aluminum +honeycomb crushable foam materials with anisotropic behavior. Three yield surfaces +are available. In the first, nonlinear elastoplastic material behavior can be defined +separately for all normal and shear stresses, which are considered to be fully +uncoupled. In the second, a yield surface is defined that considers the effects of off-axis +loading. The second yield surface is transversely isotropic. A drawback of this second +yield surface is that the material can collapse in a shear mode due to low shear +resistance. There was no obvious way of increasing the shear resistance without +changing the behavior in purely uniaxial compression. Therefore, in the third option, +the model has been modified so that the user can prescribe the shear and hydrostatic +resistance in the material without affecting the uniaxial behavior. The choice of the +second yield surface is flagged by the sign of the first load curve ID, LCA. The third +yield surface is flagged by the sign of ECCU, which becomes the initial stress yield limit +in simple shear. A description is given below. +The development of the second and third yield surfaces are based on experimental test +results of aluminum honeycomb specimens at Toyota Motor Corporation. +The default element for this material is solid type 0, a nonlinear spring type brick +element. The recommended hourglass control is the type 2 viscous formulation for one +point integrated solid elements. The stiffness form of the hourglass control when used +with this constitutive model can lead to nonphysical results since strain localization in +the shear modes can be inhibited. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +SIGY +F +6 +VF +F +7 +8 +MU +BULK +F +F +Default +none +none +none +none +none +none +.05 +0.0 +Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCA +LCB +LCC +LCS +LCAB +LCBC +LCCA +LCSR +Type +F +F +F +F +F +F +F +F +Default +none +LCA +LCA +LCA +LCS +LCS +LCS +optional + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EAAU +EBBU +ECCU +GABU +GBCU +GCAU +AOPT +MACF +Type +F +F +F +F +F +F + Card 4 +Variable +1 +XP +Type +F + Card 5 +Variable +1 +D1 +Type +F +2 +YP +F +2 +D2 +F +3 +ZP +F +3 +D3 +F +4 +A1 +F +4 +5 +A2 +F +5 +6 +A3 +F +6 +I +8 +7 +7 +8 +TSEF +SSEF +VREF +TREF +SHDFLG +F +F +F +F +F +Additional card for AOPT = 3 or AOPT = 4. + Card 6 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +5 +6 +7 +*MAT_MODIFIED_HONEYCOMB + Card 7 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCSRA +LCSRB +LCSRC +LCSRAB +LCSRBC +LCSCA +Type +F +F +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +SIGY +VF +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus for compacted honeycomb material. +Poisson’s ratio for compacted honeycomb material. +Yield stress for fully compacted honeycomb. +Relative volume at which the honeycomb is fully compacted. +This parameter is ignored for corotational solid elements, types 0 +and 9. +MU +μ, material viscosity coefficient. (default=.05) Recommended. +BULK +Bulk viscosity flag: +EQ.0.0: bulk viscosity is not used. This is recommended. +EQ.1.0: bulk viscosity is active and μ = 0. This will give results +identical to previous versions of LS-DYNA. +LCA +Load curve ID, see *DEFINE_CURVE: +LCA.LT.0: Yield stress as a function of the angle off the +material axis in degrees. +LCA.GT.0: sigma-aa versus normal strain component aa. For +the corotational solid elements, types 0 and 9, engi- +neering strain is expected, but for all other solid el- +ement formulations a logarithmic strain is expected. +See Remarks. +VARIABLE +DESCRIPTION +LCB +Load curve ID, see *DEFINE_CURVE: +LCA.LT.0: strong axis hardening stress as a function of the +volumetric strain. +LCA.GT.0: sigma-bb versus normal strain component bb. For +the corotational solid elements, types 0 and 9, engi- +neering strain is expected, but for all other solid el- +ement formulations a logarithmic strain is expected. +Default LCB = LCA. See Remarks. +LCC +Load curve ID, see *DEFINE_CURVE: +LCA.LT.0: weak axis hardening stress as a function of the +volumetric strain. +LCA.GT.0: sigma-cc versus normal strain component cc. For +the corotational solid elements, types 0 and 9, engi- +neering strain is expected, but for all other solid el- +ement formulations a logarithmic strain is expected. +Default LCC = LCA. See Remarks. +LCS +Load curve ID, see *DEFINE_CURVE: +LCA.LT.0: damage curve giving shear stress multiplier as a +function of the shear strain component. This curve +definition is optional and may be used if damage is +desired. IF SHDFLG = 0 (the default), the damage +value multiplies the stress every time step and the +stress is updated incrementally. The damage curve +should be set to unity until failure begins. After +failure the value should drop to 0.999 or 0.99 or any +number between zero and one depending on how +many steps are needed to zero the stress. Alterna- +tively, if SHDFLG = 1, the damage value is treated +as a factor that scales the shear stress compared to +the undamaged value. +LCA.GT.0: shear stress versus shear strain. For the corotational +solid elements, types 0 and 9, engineering strain is +expected, but for all other solid element formula- +tions a shear strain based on the deformed configu- + Each +ration +component of shear stress may have its own load +curve. See Remarks. + Default LCS = LCA. +is used. +*MAT_MODIFIED_HONEYCOMB +DESCRIPTION +LCAB +Load curve ID, see *DEFINE_CURVE. Default LCAB = LCS: +LCA.LT.0: damage curve giving shear ab-stress multiplier as a +function of the ab-shear strain component. This +curve definition is optional and may be used if +damage is desired. See LCS above. +LCA.GT.0: sigma-ab versus shear strain-ab. For the corotation- +al solid elements, types 0 and 9, engineering strain is +expected, but for all other solid element formula- +tions a shear strain based on the deformed configu- +ration is used. See Remarks. +LCBC +Load curve ID, see *DEFINE_CURVE. Default LCBC = LCS: +LCA.LT.0: damage curve giving bc-shear stress multiplier as a +function of the ab-shear strain component. This +curve definition is optional and may be used if +damage is desired. See LCS above. +LCA.GT.0: sigma-bc versus shear strain-bc. For the corotation- +al solid elements, types 0 and 9, engineering strain is +expected, but for all other solid element formula- +tions a shear strain based on the deformed configu- +ration is used. See Remarks. +LCCA +Load curve ID, see *DEFINE_CURVE. Default LCCA = LCS: +LCA.LT.0: damage curve giving ca-shear stress multiplier as a +function of the ca-shear strain component. This +curve definition is optional and may be used if +damage is desired. See LCS above. +LCA.GT.0: sigma-ca versus shear strain-ca. For the corotational +solid elements, types 0 and 9, engineering strain is +expected, but for all other solid element formula- +tions a shear strain based on the deformed configu- +ration is used. See Remarks. +LCSR +the +Load curve ID, see *DEFINE_CURVE, for strain-rate effects +defining +rate +factor versus +𝑖𝑗𝜀′̇ +3 (𝜀′̇ +̇ = √2 +scaled using this curve. +𝑖𝑗). This is optional. The curves defined above are +effective +strain +scale +𝜀̅ +EAAU +Elastic modulus Eaau in uncompressed configuration. +VARIABLE +DESCRIPTION +EBBU +ECCU +GABU +GBCU +GCAU +Elastic modulus Ebbu in uncompressed configuration. +Elastic modulus Eccu in uncompressed configuration. +LT.0.0: 𝜎𝑑 +𝑌, |ECCU| initial stress limit (yield) in simple shear. +Also, LCA < 0 to activate the transversely isotropic +yield surface. +Shear modulus Gabu in uncompressed configuration. +Shear modulus Gbcu in uncompressed configuration. +Shear modulus Gcau in uncompressed configuration. +ECCU.LT.0.0: 𝜎𝑝 +𝑌, GCAU +initial stress +in +hydrostatic compression. Also, LCA < 0 to acti- +vate the transversely isotropic yield surface. +(yield) +limit +AOPT +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the a-direction. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. The plane of a solid element is the +midsurface between the inner surface and outer surface +defined by the first four nodes and the last four nodes +of the connectivity of the element, respectively. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector v, and +an originating point, p, which define the centerline ax- +is. This option is for solid elements only. +*MAT_MODIFIED_HONEYCOMB +DESCRIPTION +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). +MACF +Material axes change flag: +EQ.1: No change, default, +EQ.2: switch material axes a and b, +EQ.3: switch material axes a and c, +EQ.4: switch material axes b and c. +XP YP ZP +Coordinates of point p for AOPT = 1 and 4. +A1 A2 A3 +Components of vector a for AOPT = 2. +D1 D2 D3 +Components of vector d for AOPT = 2. +V1 V2 V3 +Define components of vector v for AOPT = 3 and 4. +TSEF +SSEF +2-680 (EOS) +Tensile strain at element failure (element will erode). +VARIABLE +VREF +TREF +DESCRIPTION +This is an optional input parameter for solid elements types 1, 2, +3, 4, and 10. Relative volume at which the reference geometry is +stored. At this time the element behaves like a nonlinear spring. +The TREF, below, is reached first then VREF will have no effect. +This is an optional input parameter for solid elements types 1, 2, +3, 4, and 10. Element time step size at which the reference +geometry is stored. When this time step size is reached the +element behaves like a nonlinear spring. If VREF, above, is +reached first then TREF will have no effect. +SHDFLG +Flag defining treatment of damage from curves LCS, LCAB, +LCBC and LCCA (relevant only when LCA < 0): +LCSRA +EQ.0.0: Damage reduces shear stress every time step, +EQ.1.0: Damage = (shear stress)/(undamaged shear stress) +Optional load curve ID if LCSR = -1, see *DEFINE_CURVE, for +strain rate effects defining the scale factor for the yield stress in +the a-direction versus the natural logarithm of the absolute value +of deviatoric strain rate in the a-direction. This curve is optional. +The scale factor for the lowest value of strain rate defined by the +curve is used if the strain rate is zero. The scale factor for the +highest value of strain rate defined by the curve also defines the +upper limit of the scale factor. +LCSRB +Optional load curve ID if LCSR = -1, see *DEFINE_CURVE, for +strain rate effects defining the scale factor for the yield stress in +the b-direction versus the natural logarithm of the absolute value +of deviatoric strain +LCSRC +Similar definition as for LCSA and LCSB above. +LCSRAB +Similar definition as for LCSA and LCSB above. +LCSRBC +Similar definition as for LCSA and LCSB above. +LCSRCA +Similar definition as for LCSA and LCSB above. +Remarks: +For efficiency it is strongly recommended that the load curve ID’s: LCA, LCB, LCC, +LCS, LCAB, LCBC, and LCCA, contain exactly the same number of points with +corresponding strain values on the abscissa. If this recommendation is followed the +cost of the table lookup is insignificant. Conversely, the cost increases significantly if +the abscissa strain values are not consistent between load curves. +For solid element formulations 1 and 2, the behavior before compaction is orthotropic +where the components of the stress tensor are uncoupled, i.e., an a component of strain +will generate resistance in the local a-direction with no coupling to the local b and c +directions. The elastic moduli vary from their initial values to the fully compacted +values linearly with the relative volume: +𝐸𝑎𝑎 = 𝐸𝑎𝑎𝑢 + 𝛽(𝐸 − 𝐸𝑎𝑎𝑢) +𝐸𝑏𝑏 = 𝐸𝑏𝑏𝑢 + 𝛽(𝐸 − 𝐸𝑏𝑏𝑢) +𝐸𝑐𝑐 = 𝐸𝑐𝑐𝑢 + 𝛽(𝐸 − 𝐸𝑐𝑐𝑢) +𝐺𝑎𝑏 = 𝐸𝑎𝑏𝑢 + 𝛽(𝐺 − 𝐺𝑎𝑏𝑢) +𝐺𝑏𝑐 = 𝐺𝑏𝑐𝑢 + 𝛽(𝐺 − 𝐺𝑏𝑐𝑢) +𝐺𝑐𝑎 = 𝐺𝑐𝑎𝑢 + 𝛽(𝐺 − 𝐺𝑐𝑎𝑢) +where +𝛽 = max [min ( +1 − 𝑉 +1 − 𝑉𝑓 +, 1) , 0] +and G is the elastic shear modulus for the fully compacted honeycomb material +𝐺 = +2(1 + 𝑣) +The relative volume, V, is defined as the ratio of the current volume over the initial +volume, and typically, V = 1 at the beginning of a calculation. +For corotational solid elements, types 0 and 9, the components of the stress tensor +remain uncoupled and the uncompressed elastic moduli are used, that is, the fully +compacted elastic moduli are ignored. +The load curves define the magnitude of the stress as the material undergoes +deformation. The first value in the curve should be less than or equal to zero +corresponding to tension and increase to full compaction. Care should be taken when +defining the curves so the extrapolated values do not lead to negative yield stresses. +At the beginning of the stress update we transform each element’s stresses and strain +rates into the local element coordinate system. For the uncompacted material, the trial +stress components are updated using the elastic interpolated moduli according to: +𝑛+1trial +𝜎𝑎𝑎 += 𝜎𝑎𝑎 +𝑛 + 𝐸𝑎𝑎Δ𝜀𝑎𝑎 +𝑛+1trial +𝜎𝑐𝑐 +𝑛+1trial +𝜎𝑏𝑏 += 𝜎𝑐𝑐 += 𝜎𝑏𝑏 +𝑛 + 𝐸𝑐𝑐Δ𝜀𝑐𝑐 +𝑛 + 𝐸𝑏𝑏Δ𝜀𝑏𝑏 +𝑛+1trial +𝜎𝑎𝑏 +𝑛+1trial +𝜎𝑏𝑐 += 𝜎𝑎𝑏 +𝑛 + 2𝐺𝑎𝑏Δ𝜀𝑎𝑏 += 𝜎𝑏𝑐 +𝑛 + 2𝐺𝑏𝑐Δ𝜀𝑏𝑐 +𝑛+1trial +𝜎𝑐𝑎 += 𝜎𝑐𝑎 +𝑛 + 2𝐺𝑐𝑎Δ𝜀𝑐𝑎 +If LCA > 0, each component of the updated stress tensor is checked to ensure that it +does not exceed the permissible value determined from the load curves, e.g., if +then +𝑛+1trial +∣𝜎𝑖𝑗 +∣ > 𝜆𝜎𝑖𝑗(𝜀𝑖𝑗) +𝑛+1 = 𝜎𝑖𝑗(𝜀𝑖𝑗) +𝜎𝑖𝑗 +𝑛+1trial +𝜆𝜎𝑖𝑗 +𝑛+1trial∣ +∣𝜎𝑖𝑗 +On Card 3 𝜎𝑖𝑗(𝜀𝑖𝑗) is defined in the load curve specified in columns 31-40 for the aa +stress component, 41-50 for the bb component, 51-60 for the cc component, and 61-70 for +the ab, bc, cb shear stress components. The parameter λ is either unity or a value taken +from the load curve number, LCSR, that defines λ as a function of strain-rate. Strain- +rate is defined here as the Euclidean norm of the deviatoric strain-rate tensor. +If LCA < 0, a transversely isotropic yield surface is obtained where the uniaxial limit +stress, 𝜎 𝑦(𝜑, 𝜀vol), can be defined as a function of angle 𝜑 with the strong axis and +volumetric strain, 𝜀vol. In order to facilitate the input of data to such a limit stress +surface, the limit stress is written as: +𝜎 𝑦(𝜑, 𝜀vol) = 𝜎 𝑏(𝜑) + (cos𝜑)2𝜎 𝑠(𝜀vol) + (sin𝜑)2𝜎 𝑤(𝜀vol) +where the functions 𝜎 𝑏, 𝜎 𝑠, and 𝜎 𝑤 are represented by load curves LCA, LCB, LCC, +respectively. The latter two curves can be used to include the stiffening effects that are +observed as the foam material crushes to the point where it begins to lock up. To +ensure that the limit stress decreases with respect to the off-angle the curves should be +defined such that following equations hold: +and +∂𝜎 𝑏(𝜑) +∂𝜑 +≤ 0 +𝜎 𝑠(𝜀vol) − 𝜎 𝑤(𝜀vol) ≥ 0. +A drawback of this implementation was that the material often collapsed in shear mode +due to low shear resistance. There was no way of increasing the shear resistance +without changing the behavior in pure uniaxial compression. We have therefore +modified the model so that the user can optionally prescribe the shear and hydrostatic +resistance in the material without affecting the uniaxial behavior. We introduce the +𝑌(𝜀vol) as the hydrostatic and shear limit stresses, respectively. +parameters 𝜎𝑝 +These are functions of the volumetric strain and are assumed given by +𝑌(𝜀vol) and 𝜎𝑑 +𝑌(𝜀vol) = 𝜎𝑝 +𝜎𝑝 +𝑌(𝜀vol) = 𝜎𝑑 +𝜎𝑑 +𝑌 + 𝜎 𝑠(𝜀vol) +, +𝑌 + 𝜎 𝑠(𝜀vol) +where we have reused the densification function 𝜎 𝑠. The new parameters are the initial +𝑌, and are provided by the user as +hydrostatic and shear limit stress values, 𝜎𝑝 +GCAU and |ECCU|, respectively. The negative sign of ECCU flags the third yield +𝑌 and 𝜎𝑑 +𝑌(𝜀vol) and (iii) for a simple shear the stress limit is given by 𝜎𝑑 +surface option whenever LCA < 0. The effect of the third formulation is that (i) for a +uniaxial stress the stress limit is given by 𝜎 𝑌(𝜙, 𝜀vol), (ii) for a pressure the stress limit is +𝑌(𝜀vol). +given by 𝜎𝑝 +Experiments have shown that the model may give noisy responses and inhomogeneous +deformation modes if parameters are not chosen with care. We therefore recommend to +(i) avoid large slopes in the function 𝜎 𝑃, (ii) let the functions 𝜎 𝑠 and 𝜎 𝑤 be slightly +increasing and (iii) avoid large differences between the stress limit values 𝜎 𝑦(𝜑, 𝜀vol), +𝑌(𝜀vol). These guidelines are likely to contradict how one would +𝑌(𝜀vol) and 𝜎𝑑 +𝜎𝑝 +interpret test data and it is up to the user to find a reasonable trade-off between +matching experimental results and avoiding the mentioned numerical side effects. +For fully compacted material (element formulations 1 and 2), we assume that the +material behavior is elastic-perfectly plastic and updated the stress components +according to: +trial = 𝑠𝑖𝑗 +𝑠𝑖𝑗 +𝑛 + 2𝐺Δ𝜀𝑖𝑗 +𝑑𝑒𝑣𝑛+1 +2⁄ +where the deviatoric strain increment is defined as +Δ𝜀𝑖𝑗 +𝑑𝑒𝑣 = Δ𝜀𝑖𝑗 − +Δ𝜀𝑘𝑘𝛿𝑖𝑗. +We now check to see if the yield stress for the fully compacted material is exceeded by +comparing +trial = ( +𝑠eff +2⁄ +trial) +trial𝑠𝑖𝑗 +𝑠𝑖𝑗 +the effective trial stress to the yield stress, σy (Card 1, field 41-50). If the effective trial +stress exceeds the yield stress we simply scale back the stress components to the yield +surface +We can now update the pressure using the elastic bulk modulus, K +𝑛+1 = +𝑠𝑖𝑗 +𝜎𝑦 +trial +𝑠eff +trial. +𝑠𝑖𝑗 +𝑛+1 +𝑝𝑛+1 = 𝑝𝑛 − 𝐾Δ𝜀𝑘𝑘 +2⁄ +𝐾 = +3(1 − 2𝑣) +and obtain the final value for the Cauchy stress +𝑛+1 = 𝑠𝑖𝑗 +𝜎𝑖𝑗 +𝑛+1 − 𝑝𝑛+1𝛿𝑖𝑗 +After completing the stress update we transform the stresses back to the global +configuration. +For *CONSTRAINED_TIED_NODES_WITH_FAILURE, the failure is based on the +volume strain instead to the plastic strain. +Curve extends into negative strain +quadrant since LS-DYNA will +extrapolate using the two end points. +It is important that the extropolation +does not extend into the negative +stress region. + σ +ij +unloading and +reloading path +Strain: -ε +ij +Unloading is based on the interpolated Young’s +moduli which must provide an unloading tangent +that exceeds the loading tangent. +Figure M126-1. Stress versus strain. Note that the “yield stress” at a strain of +zero is nonzero. In the load curve definition the “time” value is the directional +strain and the “function” value is the yield stress. Note that for element types +0 and 9 engineering strains are used, but for all other element types the rates +are integrated in time. +*MAT_ARRUDA_BOYCE_RUBBER +This is Material Type 127. This material model provides a hyperelastic rubber model, +see [Arruda and Boyce 1993] combined optionally with linear viscoelasticity as outlined +by [Christensen 1980]. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +K +F +3 +Variable +LCID +TRAMP +NT +Type +F +F +F +4 +G +F +4 +5 +N +F +5 +6 +7 +8 +6 +7 +8 +Viscoelastic Constant Cards. Up to 6 cards may be input. A keyword card (with a +“*” in column 1) terminates this input if less than 6 cards are used. + Card 3 +Variable +Type +1 +GI +F + VARIABLE +MID +2 +3 +4 +5 +6 +7 +8 +BETAI +F +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +K +G +N +Bulk modulus +Shear modulus +Number of statistical links +VARIABLE +LCID +DESCRIPTION +Optional load curve ID of relaxation curve if constants βI are +determined via a least squares fit. This relaxation curve is shown +in Figure M76-1. This model ignores the constant stress. +TRAMP +Optional ramp time for loading. +NT +Number of Prony series terms in optional fit. If zero, the default +is 6. Currently, the maximum number is 6. Values less than 6, +possibly 3-5 are recommended, since each term used adds +significantly to the cost. Caution should be exercised when +taking the results from the fit. Always check the results of the fit +in the output file. Preferably, all generated coefficients should be +positive. Negative values may lead to unstable results. Once a +satisfactory fit has been achieved it is recommended that the +coefficients which are written into the output file be input in +future runs. +GI +Optional shear relaxation modulus for the ith term. +BETAI +Optional decay constant if ith term. +Remarks: +Rubber is generally considered to be fully incompressible since the bulk modulus +greatly exceeds the shear modulus in magnitude. To model the rubber as an +unconstrained material a hydrostatic work term, 𝑊𝐻(𝐽), is included in the strain energy +functional which is function of the relative volume, J, [Ogden 1984]: +𝑊(𝐽1, 𝐽2, 𝐽) = 𝑛𝑘𝜃 [ +(𝐽1 − 3) + +20𝑁 +2 − 9) + +(𝐽1 ++ 𝑛𝑘𝜃 [ +19 +7000𝑁3 (𝐽1 +4 − 81) + +3 − 27)] +11 +1050𝑁2 (𝐽1 +519 +673750𝑁4 (𝐽1 +5 − 243)] + 𝑊𝐻(𝐽) +where the hydrostatic work term is in terms of the bulk modulus, K, and the third +invariant, J, as: +Rate effects are taken into account through linear viscoelasticity by a convolution +integral of the form: +𝑊𝐻(𝐽) = +(𝐽 − 1)2 +𝜎𝑖𝑗 = ∫ 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) +∂𝜀𝑘𝑙 +∂𝜏 +𝑑𝜏 +or in terms of the second Piola-Kirchhoff stress, 𝑆𝑖𝑗, and Green's strain tensor, 𝐸𝑖𝑗, +𝑆𝑖𝑗 = ∫ 𝐺𝑖𝑗𝑘𝑙 +(𝑡 − 𝜏) +∂𝐸𝑘𝑙 +∂𝜏 +𝑑𝜏 +where 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) and 𝐺𝑖𝑗𝑘𝑙(𝑡 − 𝜏) are the relaxation functions for the different stress +measures. This stress is added to the stress tensor determined from the strain energy +functional. +If we wish to include only simple rate effects, the relaxation function is represented by +six terms from the Prony series: +given by, +𝑔(𝑡) = 𝛼0 + ∑ 𝛼𝑚𝑒−𝛽𝑡 +𝑚=1 +𝑔(𝑡) = ∑ 𝐺𝑖𝑒−𝛽𝑖𝑡 +𝑖=1 +This model is effectively a Maxwell fluid which consists of a dampers and springs in +series. We characterize this in the input by shear moduli, 𝐺𝑖, and decay constants, 𝛽𝑖. +The viscoelastic behavior is optional and an arbitrary number of terms may be used. +*MAT_128 +This is Material Type 128. This material model provides a heart tissue model described +in the paper by Walker et al [2005] as interpreted by Kay Sun. It is backward compatible +with an earlier heart tissue model described in the paper by Guccione, McCulloch, and +Waldman [1991]. Both models are transversely isotropic. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +C +F +4 +B1 +F +5 +B2 +F +6 +B3 +F +7 +P +F +8 +B +F +Skip to Card 3 to activate older Guccione, McCulloch, and Waldman [1991] model. + Card 2 +Variable +1 +L0 +2 +3 +CA0MAX +LR +4 +M +5 +BB +6 +7 +8 +CA0 +TMAX +TACT +Type +F + Card 3 +1 +I +2 +Variable +AOPT +MACF +Type +F +I +3 +4 +5 +6 +7 +8 + Card 4 +Variable +1 +XP +Type +F +2 +YP +F +3 +ZP +F +4 +A1 +F +5 +A2 +F +6 +A3 +F +7 +Variable +1 +V1 +Type +F + VARIABLE +MID +*MAT_HEART_TISSUE +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +BETA +F +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +C +B1 +B2 +B3 +P +B +L0 +Diastolic material coefficient. +𝑏1, diastolic material coefficient. +𝑏2, diastolic material coefficient. +𝑏3, diastolic material coefficient. +Pressure in the muscle tissue +Systolic material coefficient. Omit for the earlier model. +𝑙0, sacromere length at which no active tension develops. Omit +for the earlier model. +CA0MAX +(𝐶𝑎0)max, maximum peak intracellular calcium concentrate. Omit +for the earlier model. +LR +M +BB +CA0 +TMAX +TACT +𝑙𝑅, Stress-free sacromere length. Omit for the earlier model. +Systolic material coefficient. Omit for the earlier model. +Systolic material coefficient. Omit for the earlier model. +𝐶𝑎0, peak intracellular calcium concentration. Omit for the earlier +model. +𝑇max, maximum isometric tension achieved at the longest +sacromere length. Omit for the earlier model. +𝑡act, time at which active contraction initiates. Omit for the earlier +model +VARIABLE +AOPT +DESCRIPTION +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the a-direction. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector v, and +an originating point, P, which define the centerline ax- +is. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +MACF +Material axes change flag for brick elements: +EQ.1: No change, default, +EQ.2: switch material axes a and b, +EQ.3: switch material axes a and c, +EQ.4: switch material axes b and c. +XP, YP, ZP +xp yp zp, define coordinates of point p for AOPT = 1 and 4. +A1, A2, A3 +a1 a2 a3, define components of vector a for AOPT = 2. +D1, D2, D3 +d1 d2 d3, define components of vector d for AOPT = 2. +V1, V2, V3 +v1 v2 v3, define components of vector v for AOPT = 3 and 4. +Material angle in degrees for AOPT = 3, may be overridden on +the element card, see *ELEMENT_SOLID_ORTHO. +*MAT_128 + VARIABLE +BETA +Remarks: +1. The tissue model is described in terms of the energy functional that is +transversely isotropic with respect to the local fiber direction, +(𝑒𝑄 − 1) +𝑊 = +𝑄 = 𝑏𝑓 𝐸11 +2 + 𝑏𝑡(𝐸22 +2 + 𝐸33 +2 + 𝐸23 +2 + 𝐸32 +2 ) + 𝑏𝑓𝑠(𝐸12 +2 + 𝐸21 +2 + 𝐸13 +2 + 𝐸31 +2 ) +with 𝐶, 𝑏𝑓 , 𝑏𝑡, and 𝑏𝑓𝑠 material parameters and E the Lagrange-Green strains. +The systolic contraction was modeled as the sum of the passive stress derived +from the strain energy function and an active fiber directional component, 𝑇0, +which is a function of time, t, +− 𝑝𝐽𝐶−1 + 𝑇0{𝑡, 𝐶𝑎0, 𝑙} +𝑆 = +𝜎 = +∂𝑊 +∂𝐸 +𝐹𝑆𝐹𝑇 +with 𝑆 the second Piola-Kirchoff stress tensor, 𝐶 the right Cauchy-Green de- +formation tensor, J the Jacobian of the deformation gradient tensor 𝐹, and 𝜎 the +Cauchy stress tensor. +The active fiber directional stress component is defined by a time-varying elas- +tance model, which at end-systole, is reduced to +𝑇0 = 𝑇max +𝐶𝑎0 +2 + 𝐸𝐶𝑎50 +2 𝐶𝑡 +𝐶𝑎0 +with 𝑇max the maximum isometric tension achieved at the longest sacromere +length and maximum peak intracellular calcium concentration. The length- +dependent calcium sensitivity and internal variable is given by, +𝐸𝐶𝑎50 = +(𝐶𝑎0)max +√exp[𝐵(𝑙 − 𝑙0] − 1 +𝐶𝑡 = 1/2(1 − cos 𝑤) +𝑙 = 𝑙𝑅√2𝐸11 + 1 +𝑤 = 𝜋 +0.25 + 𝑡𝑟 +𝑡𝑟 +𝑡𝑟 = 𝑚𝑙 + 𝑏𝑏 +A cross-fiber, in-plane stress equivalent to 40% of that along the myocardial +fiber direction is added. +2. The earlier tissue model is described in terms of the energy functional in terms +of the Green strain components, 𝐸𝑖𝑗, +𝑊(𝐸) = +(𝑒𝑄 − 1) + +𝑄 = 𝑏1𝐸11 +2 + 𝐸33 +2 + 𝑏2(𝐸22 +𝑃(𝐼3 − 1) +2 + 𝐸23 +2 + 𝐸32 +2 ) + 𝑏3(𝐸12 +2 + 𝐸21 +2 + 𝐸13 +2 + 𝐸31 +2 ) +The Green components are modified to eliminate any effects of volumetric +work following the procedures of Ogden. See the paper by Guccione et al +[1991] for more detail. +*MAT_LUNG_TISSUE +This is Material Type 129. This material model provides a hyperelastic model for heart +tissue, see [Vawter 1980] combined optionally with linear viscoelasticity as outlined by +[Christensen 1980]. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F + Card 2 +Variable +1 +C1 +Type +F +2 +C2 +F +3 +K +F +3 +4 +C +F +4 +5 +6 +7 +8 +DELTA +ALPHA +BETA +F +5 +F +6 +F +7 +8 +LCID +TRAMP +NT +F +F +F +Viscoelastic Constant Cards. Up to 6 cards may be input. A keyword card (with a +“*” in column 1) terminates this input if less than 6 cards are used. + Card 3 +Variable +Type +1 +GI +F +2 +3 +4 +5 +6 +7 +8 +BETAI +F + VARIABLE +DESCRIPTION +MID +RO +K +C +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Bulk modulus +Material coefficient. +DELTA +Δ, material coefficient. +ALPHA +𝛼, material coefficient. +VARIABLE +DESCRIPTION +BETA +𝛽, material coefficient. +C1 +C2 +Material coefficient. +Material coefficient. +LCID +Optional load curve ID of relaxation curve +If constants 𝐺𝑖 and 𝛽𝑖 are determined via a least squares fit. +This relaxation curve is shown in Figure M76-1. This model +ignores the constant stress. +TRAMP +Optional ramp time for loading. +NT +Number of Prony series terms in optional fit. If zero, the default +is 6. Currently, the maximum number is 6. Values less than 6, +possibly 3 - 5 are recommended, since each term used adds +significantly to the cost. Caution should be exercised when +taking the results from the fit. Always check the results of the fit +in the output file. Preferably, all generated coefficients should be +positive. Negative values may lead to unstable results. Once a +satisfactory fit has been achieved it is recommended that the +coefficients which are written into the output file be input in +future runs. +Gi +Optional shear relaxation modulus for the ith term +BETAi +Optional decay constant if ith term +Remarks: +The material is described by a strain energy functional expressed in terms of the +invariants of the Green Strain: +𝑊(𝐼1, 𝐼2) = +2Δ +𝑒(𝛼𝐼1 +2+𝛽𝐼2) + +12𝐶1 +Δ(1 + 𝐶2) +[𝐴(1+𝐶2) − 1] +𝐴2 = +(𝐼1 + 𝐼2) − 1 +where the hydrostatic work term is in terms of the bulk modulus, K, and the third +invariant, J, as: +𝑊𝐻(𝐽) = +(𝐽 − 1)2 +Rate effects are taken into account through linear viscoelasticity by a convolution +integral of the form: +𝜎𝑖𝑗 = ∫ 𝑔𝑖𝑗𝑘𝑙 +(𝑡 − 𝜏) +∂𝜀𝑘𝑙 +∂𝜏 +𝑑𝜏 +or in terms of the second Piola-Kirchhoff stress, 𝑆𝑖𝑗, and Green's strain tensor, 𝐸𝑖𝑗, +𝑆𝑖𝑗 = ∫ 𝐺𝑖𝑗𝑘𝑙 +(𝑡 − 𝜏) +∂ 𝐸𝑘𝑙 +∂𝜏 +𝑑𝜏 +where 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) and 𝐺𝑖𝑗𝑘𝑙(𝑡 − 𝜏) are the relaxation functions for the different stress +measures. This stress is added to the stress tensor determined from the strain energy +functional. +If we wish to include only simple rate effects, the relaxation function is represented by +six terms from the Prony series: +given by, +𝑔(𝑡) = 𝛼0 + ∑ 𝛼𝑚 +𝑚=1 +𝑒−𝛽 𝑡 +𝑔(𝑡) = ∑ 𝐺𝑖𝑒−𝛽𝑖 𝑡 +𝑖=1 +This model is effectively a Maxwell fluid which consists of a dampers and springs in +series. We characterize this in the input by shear moduli, 𝐺𝑖, and decay constants, 𝛽𝑖. +The viscoelastic behavior is optional and an arbitrary number of terms may be used. +*MAT_130 +This is Material Type 130. This model is available the Belytschko-Tsay and the C0 +triangular shell elements and is based on a resultant stress formulation. In-plane +behavior is treated separately from bending in order to model perforated materials such +as television shadow masks. If other shell formulations are specified, the formulation +will be automatically switched to Belytschko-Tsay. As implemented, this material +model cannot be used with user defined integration rules. +NOTE: This material does not support specification of a ma- +terial angle, 𝛽𝑖, for each through-thickness integra- +tion point of a shell. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +YS +F +3 +4 +EP +F +4 +5 +6 +7 +8 +5 +6 +7 +8 +Variable +E11P +E22P +V12P +V21P +G12P +G23P +G31P +Type +F + Card 3 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +8 +Variable +E11B +E22B +V12B +V21B +G12B +AOPT +Type +F + Card 4 +1 +F +2 +F +3 +Variable +Type +F +F +F +4 +A1 +F +5 +A2 +F +6 +A3 +F +7 +Variable +1 +V1 +Type +F +*MAT_SPECIAL_ORTHOTROPIC +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +BETA +F + VARIABLE +DESCRIPTION +MID +RO +YS +EP +E11P +E22P +V12P +V11P +G12P +G23P +G31P +E11B +E22B +V12B +V21B +G12B +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Yield stress. This parameter is optional and is approximates the +yield condition. Set to zero if the behavior is elastic. +Plastic hardening modulus. +𝐸11𝑝, for in plane behavior. +𝐸22𝑝, for in plane behavior. +𝜈12𝑝, for in plane behavior. +𝜈11𝑝, for in plane behavior. +𝐺12𝑝, for in plane behavior. +𝐺23𝑝, for in plane behavior. +𝐺31𝑝, for in plane behavior. +𝐸11𝑝, for bending behavior. +𝐸22𝑝, for bending behavior. +𝜈12𝑏, for bending behavior. +𝜈21𝑏, for bending behavior. +𝐺12𝑏, for bending behavior. +VARIABLE +AOPT +DESCRIPTION +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the shell ele- +ment normal by an angle BETA. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector 𝐯 with the +element normal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +A1, A2, A3 +(𝑎1, 𝑎2, 𝑎3), define components of vector 𝐚 for AOPT = 2. +D1, D2, D3 +(𝑑1, 𝑑2, 𝑑3), define components of vector 𝐝 for AOPT = 2. +V1 ,V2, V3 +(𝑣1, 𝑣2, 𝑣3), define components of vector 𝐯 for AOPT = 3. +BETA +Material angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA. +Remarks: +The in-plane elastic matrix for in-plane, plane stress behavior is given by: +𝐂in plane = +𝑄11𝑝 𝑄12𝑝 0 0 0 +⎤ +𝑄12𝑝 𝑄22𝑝 0 0 0 +⎥ +⎥ + 0 0 𝑄44𝑝 0 0 +⎥ +⎥ + 0 0 0 𝑄55𝑝 0 +⎥ + 0 0 0 0 𝑄66𝑝⎦ +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +The terms 𝑄𝑖𝑗𝑝 are defined as: +𝑄11𝑝 = +𝑄22𝑝 = +𝑄12𝑝 = +𝐸11𝑝 +1 − 𝜈12𝑝𝜈21𝑝 +𝐸22𝑝 +1 − 𝜈12𝑝𝜈21𝑝 +𝜈12𝑝𝐸11𝑝 +1 − 𝜈12𝑝𝜈21𝑝 +𝑄44𝑝 = 𝐺12𝑝 +𝑄55𝑝 = 𝐺23𝑝 +𝑄66𝑝 = 𝐺31𝑝 +The elastic matrix for bending behavior is given by: +𝐂bending = +𝑄11𝑏 𝑄12𝑏 0 +⎤ +⎡ +𝑄12𝑏 𝑄22𝑏 0 +⎥ +⎢ + 0 0 𝑄44𝑏⎦ +⎣ +The terms 𝑄𝑖𝑗𝑝 are similarly defined. +Because this is a resultant formulation, nothing is written to the six stress slots of d3plot. +Resultant forces and moments may be written to elout and to dynain in place of the six +stresses. The first two extra history variables may be used to complete output of the +eight resultants to elout and dynain. +*MAT_ISOTROPIC_SMEARED_CRACK +This is Material Type 131. This model was developed by Lemmen and Meijer [2001] as +a smeared crack model for isotropic materials. This model is available of solid elements +only and is restricted to cracks in the x-y plane. Users should choose other models +unless they have the report by Lemmen and Meijer [2001]. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +6 +ISPL +SIGF +I +F +7 +GK +F +8 +SR +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus +Poisson’s ratio +ISPL +Failure option: +EQ.0: Maximum principal stress criterion +EQ.5: Smeared crack model +EQ.6: Damage model based on modified von Mises strain +SIGF +Peak stress. +GK +SR +Critical energy release rate. +Strength ratio. +Remarks: +The following documentation is taken nearly verbatim from the documentation of +Lemmen and Meijer [2001]. +Three methods are offered to model progressive failure. The maximum principal stress +criterion detects failure if the maximum (most tensile) principal stress exceeds 𝜎max. +Upon failure, the material can no longer carry stress. +The second failure model is the smeared crack model with linear softening stress-strain +using equivalent uniaxial strains. Failure is assumed to be perpendicular to the +principal strain directions. A rotational crack concept is employed in which the crack +directions are related to the current directions of principal strain. Therefore crack +directions may rotate in time. Principal stresses are expressed as +E̅̅̅̅̅1 +⎡ +⎢⎢ +⎣ +E̅̅̅̅̅1𝜀̃1 +⎟⎟⎟⎞ +E̅̅̅̅̅2𝜀̃2 +E̅̅̅̅̅3𝜀̃3⎠ +⎤ +⎥⎥ +E̅̅̅̅̅3⎦ +𝜎1 +𝜎2 +𝜎3⎠ +𝜀̃1 +𝜀̃2 +𝜀̃3⎠ +E̅̅̅̅̅2 +(131.1) +⎟⎟⎞ = +⎟⎞ = +⎜⎜⎜⎛ +⎝ +⎜⎜⎛ +⎝ +⎜⎛ +⎝ +with E̅̅̅̅̅1, E̅̅̅̅̅2 and E̅̅̅̅̅3 secant stiffness in the terms that depend on internal variables. +In the model developed for DYCOSS it has been assumed that there is no interaction +between the three directions in which case stresses simply follow from +𝜎𝑗(𝜀̃𝑗) = +⎧E𝜀̃𝑗 +{{{ +⎨ +{{{ +⎩ +𝜎̅̅̅̅̅ (1 − +𝑖𝑓 +0 ≤ 𝜀̃𝑗 ≤ 𝜀̃𝑗,ini +𝜀̃𝑗 − 𝜀̃𝑗,ini +𝜀̃𝑗,ult − 𝜀̃𝑗,ini +) 𝑖𝑓 +𝜀̃𝑗,ini < 𝜀̃𝑗 ≤ 𝜀̃𝑗,ult +(131.2) +𝑖𝑓 +𝜀̃𝑗 > 𝜀̃𝑗,ult +with 𝜎̅̅̅̅̅ the ultimate stress, 𝜀̃𝑗,inithe damage threshold, and 𝜀̃𝑗,ultthe ultimate strain in j- +direction. The damage threshold is defined as +𝜀̃𝑗,ini = +𝜎̅̅̅̅̅ +(131.3) +The ultimate strain is obtained by relating the crack growth energy and the dissipated +energy +∫ ∫ 𝜎̅̅̅̅̅𝑑𝜀̃𝑗,ult𝑑𝑉 = 𝐺𝐴 +(131.4) +with G the energy release rate, V the element volume and A the area perpendicular to +the principal strain direction. The one point elements LS-DYNA have a single +integration point and the integral over the volume may be replaced by the volume. For +linear softening it follows +𝜀̃𝑗,ult = +2𝐺𝐴 +𝑉𝜎̅̅̅̅̅ +(131.5) +The above formulation may be regarded as a damage equivalent to the maximum +principle stress criterion. +The third model is a damage model represented by Brekelmans et. al [1991]. Here the +Cauchy stress tensor 𝜎 is expressed as +𝜎 = (1 − 𝐷)E𝜀 +(131.6) +where D represents the current damage and the factor (1-D) is the reduction factor +caused by damage. The scalar damage variable is expressed as function of a so-called +damage equivalent strain 𝜀𝑑 +𝐷 = 𝐷(𝜀𝑑) = 1 − +𝜀ini(𝜀ult − 𝜀𝑑) +𝜀𝑑(𝜀ult − 𝜀ini) +and +𝜀𝑑 = +𝑘 − 1 +2𝑘(1 − 2𝑣) +𝐽1 + +2𝑘 +√( +𝑘 − 1 +1 − 2𝑣 +𝐽1) ++ +6𝑘 +(1 + 𝑣)2 𝐽2 +(131.7) +(131.8) +where the constant k represents the ratio of the strength in tension over the strength in +compression +𝑘 = +𝜎ult ,tension +𝜎ult, compression +(131.9) +J1 resp. J2 are the first and second invariant of the strain tensor representing the +volumetric and the deviatoric straining respectively +𝐽1 = tr(𝜀) +𝐽2 = tr(𝜀 ⋅ 𝜀) − +[𝑡𝑟(𝜀)]2 +(131.10) +If the compression and tension strength are equal the dependency on the volumetric +strain vanishes in (8) and failure is shear dominated. If the compressive strength is +much larger than the strength in tension, k becomes small and the J1 terms in (131.8) +dominate the behavior. +*MAT_ORTHOTROPIC_SMEARED_CRACK +This is Material Type 132. This material is a smeared crack model for orthotropic +materials. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +EA +F +3 +4 +EB +F +4 +5 +EC +F +5 +6 +7 +8 +PRBA +PRCA +PRCB +F +6 +F +7 +F +8 +Variable +UINS +UISS +CERRMI CERRMII +IND +ISD +Type +F + Card 3 +1 +F +2 +F +3 +F +4 +Variable +GAB +GBC +GCA +AOPT +Type +F +F +F +F + Card 4 +Variable +1 +XP +Type +F + Card 5 +Variable +1 +V1 +Type +F +2 +YP +F +2 +V2 +F +3 +ZP +F +3 +V3 +F +4 +A1 +F +4 +D1 +F +I +5 +5 +A2 +F +5 +D2 +F +I +6 +6 +A3 +F +6 +D3 +F +7 +8 +7 +8 +MACF +I +7 +8 +BETA +REF +F +VARIABLE +DESCRIPTION +MID +RO +EA +EB +EC +PRBA +PRCA +PRCB +UINS +UISS +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Ea, Young’s modulus in a-direction. +Eb, Young’s modulus in b-direction. +Ec, Young’s modulus in c-direction +ba, Poisson’s ratio ba. +νca, Poisson’s ratio ca. +cb, Poisson’s ratio cb. +Ultimate interlaminar normal stress. +Ultimate interlaminar shear stress. +CERRMI +Critical energy release rate mode I +CERRMII +Critical energy release rate mode II +IND +Interlaminar normal direction : +EQ.1.0: Along local a axis +EQ.2.0: Along local b axis +EQ.3.0: Along local c axis +ISD +Interlaminar shear direction : +EQ.4.0: Along local ab axis +EQ.5.0: Along local bc axis +EQ.6.0: Along local ca axis +GAB +GBC +GCA +Gab, shear modulus ab. +Gbc, shear modulus bc. +Gca, shear modulus ca. +*MAT_ORTHOTROPIC_SMEARED_CRACK +DESCRIPTION +AOPT +Material axes option, see Figure 2.1. +EQ.0.0: locally orthotropic with material axes determined by +element nodes as shown in Figure 2.1. Nodes 1, 2, and +4 of an element are identical to the nodes used for the +definition of a coordinate system as by *DEFINE_CO- +ORDINATE_NODES. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the a-direction. This option is for solid +elements only. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. The plane of a solid element is the +midsurface between the inner surface and outer surface +defined by the first four nodes and the last four nodes +of the connectivity of the element, respectively. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector v, and +an originating point, P, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +XP YP ZP +Define coordinates of point p for AOPT = 1 and 4. +A1 A2 A3 +Define components of vector a for AOPT = 2. +VARIABLE +DESCRIPTION +MACF +Material axes change flag for brick elements: +EQ.1: No change, default, +EQ.2: switch material axes a and b, +EQ.3: switch material axes a and c, +EQ.4: switch material axes b and c. +V1 V2 V3 +Define components of vector v for AOPT = 3 and 4. +D1 D2 D3 +Define components of vector d for AOPT = 2: +BETA +REF +Material angle in degrees for AOPT = 3, may be overridden on +the element card, see *ELEMENT_SOLID_ORTHO. +Use reference geometry to initialize the stress tensor. The +reference geometry is defined by the keyword: *INITIAL_- +FOAM_REFERENCE_GEOMETRY . +EQ.0.0: off, +EQ.1.0: on. +Remarks: +This is an orthotropic material with optional delamination failure for brittle composites. +The elastic formulation is identical to the DYNA3D model that uses total strain +formulation. The constitutive matrix C that relates to global components of stress to the +global components of strain is defined as: +C = T𝑇C𝐿T +where T is the transformation matrix between the local material coordinate system and +the global system and C𝐿is the constitutive matrix defined in terms of the material +constants of the local orthogonal material axes a, b, and c . +Failure is described using linear softening stress strain curves for interlaminar normal +and interlaminar shear direction. The current implementation for failure is essentially +2-D. Damage can occur in interlaminar normal direction and a single interlaminar +shear direction. The orientation of these directions w.r.t. the principal material +directions have to be specified by the user. +Based on specified values for the ultimate stress and the critical energy release rate +bounding surfaces are defined +𝑓𝑛 = 𝜎𝑛 − 𝜎̅̅̅̅̅𝑛(𝜀𝑛) +𝑓𝑠 = 𝜎𝑠 − 𝜎̅̅̅̅̅𝑠(𝜀𝑠) +where the subscripts n and s refer to the normal and shear component. If stresses +exceed the bounding surfaces inelastic straining occurs. The ultimate strain is obtained +by relating the crack growth energy and the dissipated energy. For solid elements with +a single integration point it can be derived +𝜀𝑖,ult = +2𝐺𝑖𝐴 +𝑉𝜎𝑖,ult +with 𝐺𝑖the critical energy release rate, 𝑉the element volume, A the area perpendicular +to the active normal direction and 𝜎𝑖, ult the ultimate stress. For the normal component +failure can only occur under tensile loading. For shear component the behavior is +symmetric around zero. The resulting stress bounds are depicted in Figure M132-1. +Unloading is modeled with a Secant stiffness. +n,ult +ult +Figure M132-1. Shows stress bounds for the active normal component (left) +and the archive shear component (right). +-τ +ult +*MAT_133 +This is Material Type 133. This model was developed by Barlat et al. [2003] to +overcome some shortcomings of the six parameter Barlat model implemented as +material 33 (MAT_BARLAT_YLD96) in LS-DYNA. This model is available for shell +elements only. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F + Card 2 +Variable +Type +1 +K +F +2 +E0 +F +3 +E +F +3 +N +F +4 +PR +F +4 +C +F +5 +FIT +F +5 +P +F +6 +7 +8 +BETA +ITER +ISCALE +F +8 +F +6 +HARD +F +F +7 +A +F +Chaboche-Roussilier Card. Additional Card for A < 0. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CRC1 +CRA1 +CRC2 +CRA2 +CRC3 +CRA3 +CRC4 +CRA4 +Type +F +F +F +F +F +F +F +F +Direct Material Parameter Card. Additional card for FIT = 0. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ALPHA1 +ALPHA2 +ALPHA3 +ALPHA4 +ALPHA5 +ALPHA6 +ALPHA7 +ALPHA8 +Type +F +F +F +F +F +F +F +Test Data Card 1. Additional Card for FIT = 1. + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SIG00 +SIG45 +SIG90 +R00 +R45 +R90 +Type +F +F +F +F +F +F +Test Data Card 2. Additional Card for FIT = 1. + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SIGXX +SIGYY +SIGXY +DXX +DYY +DXY +Type +F +F +F +F +F +F +Hansel Hardening Card 1. Additional Card for HARD = 3. + Card 7 +Variable +1 +CP +Type +F +2 +T0 +F +3 +4 +5 +6 +7 +8 +TREF +TA0 +F +F +Hansel Hardening Card 2. Additional Card for HARD = 3. + Card 8 +Variable +Type +1 +A +F +2 +B +F +3 +C +F +4 +D +F +5 +P +F +6 +Q +F +7 +8 +E0MART +VM0 +F +F +Hansel Hardening Card 3. Additional Card for HARD = 3. + Card 9 +1 +2 +Variable +AHS +BHS +Type +F +F +3 +M +F +4 +N +F +5 +6 +EPS0 +HMART +F +F +7 +K1 +F +8 +K2 +Card 10 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +AOPT +OFFANG +P4 +HTFLAG +HTA +HTB +HTC +HTD +Type +F + Card 11 +1 +Variable +Type + Card 12 +Variable +1 +V1 +Type +F + VARIABLE +MID +RO +E +PR +FIT +F +F +F +F +2 +2 +V2 +F +F +3 +3 +V3 +F +4 +A1 +F +4 +D1 +F +5 +A2 +F +5 +D2 +F +DESCRIPTION +F +7 +F +8 +7 +8 +6 +A3 +F +6 +D3 +USRFAIL +F +F +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus +LE.0: -E is load curve ID for Young’s modulus vs. plastic strain +Poisson’s ratio +Material parameter fit flag: +EQ.0.0: Material parameters are used directly on card 3. +EQ.1.0: Material parameters are determined from test data on +cards 3 and 4 +BETA +Hardening parameter. Any value ranging from 0 (isotropic +hardening) to 1 (kinematic hardening) may be input. +*MAT_BARLAT_YLD2000 +DESCRIPTION +ITER +Plastic iteration flag: +EQ.0.0: Plane stress algorithm for stress return +EQ.1.0: Secant iteration algorithm for stress return +ITER provides an option of using three secant iterations for +determining the thickness strain increment as experiments have +shown that this leads to a more accurate prediction of shell +thickness changes for rapid processes. A significant increase in +computation time is incurred with this option so it should be used +only for applications associated with high rates of loading and/or +for implicit analysis. +ISCALE +Yield locus scaling flag: +EQ.0.0: Scaling on – reference direction = rolling direction +(default) +EQ.1.0: Scaling off – reference direction arbitrary +K +Material parameter: +HARD.EQ.1.0: 𝑘, strength coefficient for exponential hardening +HARD.EQ.2.0: 𝑎 in Voce hardening law +HARD.EQ.4.0: 𝑘, strength coefficient for Gosh hardening +HARD.EQ.5.0: 𝑎 in Hocket-Sherby hardening law +E0 +Material parameter: +HARD.EQ.1.0: 𝑒0, strain at yield for exponential hardening +HARD.EQ.2.0: 𝑏 in Voce hardening law +HARD.EQ.4.0: 𝜀0, strain at yield for Gosh hardening +HARD.EQ.5.0: 𝑏 in Hocket-Sherby hardening law +N +Material parameter: +HARD.EQ.1.0: 𝑛, exponent for exponential hardening +HARD.EQ.2.0: 𝑐 in Voce hardening law +HARD.EQ.4.0: 𝑛, exponent for Gosh hardening +HARD.EQ.5.0: 𝑐 in Hocket-Sherby hardening law +C +Cowper-Symonds strain rate parameter, C, see formula below. +VARIABLE +DESCRIPTION +P +Cowper-Symonds strain rate parameter, 𝑝. +𝜎𝑦 +𝑣(𝜀𝑝, 𝜀̇𝑝) = 𝜎𝑦(𝜀𝑝) +⎜⎛1 + [ +⎝ +𝜀̇𝑝 +1/𝑝 +] +⎟⎞ +⎠ +HARD +Hardening law: +EQ.1.0: Exponential hardening: 𝜎𝑦 = 𝑘(𝜀0 + 𝜀𝑝) +EQ.2.0: Voce hardening: 𝜎𝑦 = 𝑎 − 𝑏𝑒−𝑐𝜀𝑝 +EQ.3.0: Hansel hardening +EQ.4.0: Gosh hardening: 𝜎𝑦 = 𝑘(𝜀0 + 𝜀𝑝) +− 𝑝 +EQ.5.0: Hocket-Sherby hardening: 𝜎𝑦 = 𝑎 − 𝑏𝑒−𝑐𝜀𝑝 +LT.0.0: Absolute value defines load curve ID or table ID with +yield stress as functions of plastic strain and in the lat- +ter case also plastic strain rate. +A +CRCn +CRAn +Flow potential exponent. For face centered cubic (FCC) materials +A = 8 is recommended and for body centered cubic (BCC) +materials A = 6 may be used. +Chaboche-Rousselier kinematic hardening parameters, see +remarks. +Chaboche-Rousselier kinematic hardening parameters, see +remarks. +ALPHA1 +𝛼1, see equations below +⋮ +⋮ +ALPHA8 +𝛼8, see equations below +SIG00 +SIG45 +SIG90 +R00 +R45 +Yield stress in 00 direction +Yield stress in 45 direction +Yield stress in 90 direction +𝑅-value in 00 direction +𝑅-value in 45 direction +*MAT_BARLAT_YLD2000 +DESCRIPTION +R90 +𝑅-value in 90 direction +SIGXX +SIGYY +SIGXY +DXX +DYY +DXY +CP +T0 +TREF +TA0 +A +B +C +D +P +Q +𝑥𝑥-component of stress on yield surface . +𝑦𝑦-component of stress on yield surface . +𝑥𝑦-component of stress on yield surface . +𝑥𝑥-component of tangent to yield surface . +𝑦𝑦-component of tangent to yield surface . +𝑥𝑦-component of tangent to yield surface . +Adiabatic temperature calculation option: +EQ.0.0: Adiabatic temperature calculation is disabled. +GT.0.0: CP is the specific heat 𝐶𝑝. Adiabatic temperature +calculation is enabled. +Initial temperature 𝑇0 of the material if adiabatic temperature +calculation is enabled. +Reference temperature for output of the yield stress as history +variable. +Reference temperature 𝑇𝐴0, the absolute zero for the used +temperature scale, e.g. -273.15 if the Celsius scale is used and 0.0 +if the Kelvin scale is used. +Martensite rate equation parameter 𝐴, see equations below. +Martensite rate equation parameter 𝐵, see equations below. +Martensite rate equation parameter 𝐶, see equations below. +Martensite rate equation parameter 𝐷, see equations below. +Martensite rate equation parameter 𝑝, see equations below. +Martensite rate equation parameter 𝑄, see equations below. +E0MART +Martensite rate equation parameter 𝐸0(mart) , see equations below. +VARIABLE +VM0 +DESCRIPTION +The initial volume fraction of martensite 0.0 < 𝑉𝑚0 < 1.0 may be +initialised using two different methods: +GT.0.0: 𝑉𝑚0 is set to VM0. +LT.0.0: Can be used only when there are initial plastic strains +εp present, e.g. + when using *INITIAL_STRESS_- +SHELL. The absolute value of VM0 is then the load +curve ID for a function f that sets 𝑉𝑚0 = 𝑓 (𝜀𝑝). The +function f must be a monotonically nondecreasing +function of 𝜀𝑝. +AHS +BHS +M +N +Hardening law parameter𝐴HS, see equations below. +Hardening law parameter𝐵HS, see equations below. +Hardening law parameter 𝑚, see equations below. +Hardening law parameter 𝑛, see equations below. +EPS0 +Hardening law parameter 𝜀0, see equations below. +HMART +Hardening law parameter Δ𝐻𝛾→𝛼’, see equations below. +K1 +K2 +Hardening law parameter 𝐾1, see equations below. +Hardening law parameter 𝐾2, see equations below +AOPT +Material axes option: +EQ.0.0: locally orthotropic with material axes determined by +element nodes as shown in Figure M133-1. Nodes 1, 2, +and 4 of an element are identical to the nodes used for +the definition of a coordinate system as by *DEFINE_- +COORDINATE_NODES +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR +EQ.3.0: locally orthotropic material axes determined by +offsetting the material axes by an angle, OFFANG, +from a line determined by taking the cross product of +the vector v with the normal to the plane of the ele- +ment. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*MAT_BARLAT_YLD2000 +DESCRIPTION +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +OFFANG +Offset angle for AOPT = 3 +P4 +Material parameter: +HARD.EQ.4.0: 𝑝 in Gosh hardening law +HARD.EQ.5.0: 𝑞 in Hocket-Sherby hardening law +HTFLAG +Heat treatment flag : +HTFLAG.EQ.0: Preforming stage +HTFLAG.EQ.1: Heat treatment stage +HTFLAG.EQ.2: Postforming stage +HTA +HTB +HTC +HTD +Load curve/Table ID for postforming parameter A +Load curve/Table ID for postforming parameter B +Load curve/Table ID for postforming parameter C +Load curve/Table ID for postforming parameter D +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2 +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3 +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2 +USRFAIL +User defined failure flag +EQ.0: no user subroutine is called +EQ.1: user subroutine matusr_24 in dyn21.f is called +Remarks: +1. Strain rate is accounted for using the Cowper and Symonds model which scales +the yield stress with the factor +1 + ( +𝑝⁄ +) +𝜀̇ +where 𝜀̇ is the strain rate. To ignore strain rate effects set both C and P to zero. +2. The yield condition for this material can be written +𝑓 (σ,α, 𝜀𝑝) = 𝜎eff(𝜎𝑥𝑥 − 2𝛼𝑥𝑥 − 𝛼𝑦𝑦, 𝜎𝑦𝑦 − 2𝛼𝑦𝑦 − 𝛼𝑥𝑥, 𝜎𝑥𝑦 − 𝛼𝑥𝑦) − 𝜎𝑌 +𝑡 (𝜀𝑝, 𝜀̇𝑝, 𝛽) ≤ 0 +where +𝜎eff(𝑠𝑥𝑥, 𝑠𝑦𝑦, 𝑠𝑥𝑦) = [ +1/𝑎 +(𝜑′ + 𝜑′′)] +𝜑′ = ∣𝑋′1 − 𝑋′2∣𝑎 +𝜑′′ = ∣2𝑋1 +′′ + X2 +′′∣𝑎 + ∣X1 +′′ + 2X2 +′′∣𝑎. +The 𝑋′𝑖 and 𝑋′′𝑖 are eigenvalues of 𝑋′𝑖𝑗 and 𝑋′′𝑖𝑗 and are given by +and +′ = +𝑋1 +′ = +𝑋2 +′′ = +𝑋1 +′′ = +𝑋2 +(𝑋11 +′ + 𝑋22 +′ + √(𝑋11 +′ − 𝑋22 +′ )2 + 4𝑋12 +′ 2) +(𝑋11 +′ + 𝑋22 +′ − √(𝑋11 +′ − 𝑋22 +′ )2 + 4𝑋12 +′ 2) +(𝑋11 +′′ + 𝑋22 +′′ + √(𝑋11 +′′ − 𝑋22 +′′ )2 + 4𝑋12 +′′ 2) +(𝑋11 +′′ + 𝑋22 +′′ − √(𝑋11 +′′ − 𝑋22 +′′ )2 + 4𝑋12 +′′ 2) +respectively. The 𝑋′𝑖𝑗 and 𝑋′′𝑖𝑗 are given by +′ +𝑋11 +⎟⎟⎟⎞ +′ +𝑋22 +′ ⎠ +𝑋12 +′′ +𝑋11 +⎟⎟⎟⎞ +′′ +𝑋22 +′′ ⎠ +𝑋12 +⎜⎜⎜⎛ +⎝ +⎜⎜⎜⎛ +⎝ += += +′ +𝐿11 +′ +𝐿21 +⎜⎜⎜⎛ +⎝ +′′ +𝐿11 +′′ +𝐿21 +⎜⎜⎜⎛ +⎝ +′ +𝐿12 +′ +𝐿22 +′′ +𝐿12 +′′ +𝐿22 +⎟⎟⎟⎞ +′ ⎠ +𝐿33 +⎟⎟⎟⎞ +′′ ⎠ +𝐿33 +𝑠𝑥𝑥 +⎟⎞ +𝑠𝑦𝑦 +𝑠𝑥𝑦⎠ +⎜⎛ +⎝ +𝑠𝑥𝑥 +⎟⎞ +𝑠𝑦𝑦 +𝑠𝑥𝑦⎠ +⎜⎛ +⎝ +Where, +⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎞ +′ +𝐿11 +′ +𝐿12 +′ +𝐿21 +′ +𝐿22 +′ ⎠ +𝐿33 +′′ +𝐿11 +′′ +𝐿12 +′′ +𝐿21 +′′ +𝐿22 +′′ ⎠ +𝐿33 +⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎞ +⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎛ +⎝ +⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎛ +⎝ += +−1 +0 −1 +⎜⎜⎜⎜⎜⎜⎜⎛ +⎝ +⎟⎟⎟⎟⎟⎟⎟⎞ +3⎠ +𝛼1 +⎟⎞ +𝛼2 +𝛼7⎠ +⎜⎛ +⎝ += +⎜⎜⎜⎜⎜⎜⎜⎛ +⎝ +−2 +1 −4 −4 +4 −4 −4 +8 −2 +2 −2 +−2 +⎟⎟⎟⎟⎟⎟⎟⎞ +9⎠ +⎟⎟⎟⎟⎟⎟⎟⎞ +𝛼3 +𝛼4 +𝛼5 +𝛼6 +𝛼8⎠ +⎜⎜⎜⎜⎜⎜⎜⎛ +⎝ +The parameters 𝛼1 to 𝛼8 are the parameters that determines the shape of the +yield surface. +The material parameters can be determined from three uniaxial tests and a +more general test. From the uniaxial tests the yield stress and R-values are used +and from the general test an arbitrary point on the yield surface is used given +by the stress components in the material system as +𝛔 = +𝜎𝑥𝑥 +⎟⎟⎞ +𝜎𝑦𝑦 +𝜎𝑥𝑦⎠ +⎜⎜⎛ +⎝ +together with a tangent of the yield surface in that particular point. For the +latter the tangential direction should be determined so that +𝑑𝑥𝑥𝜀̇𝑥𝑥 +𝑝 + 𝑑𝑦𝑦𝜀̇𝑦𝑦 +𝑝 + 2𝑑𝑥𝑦𝜀̇𝑥𝑦 +𝑝 = 0 +The biaxial data can be set to zero in the input deck for LS-DYNA to just fit the +uniaxial data. +3. A kinematic hardening model is implemented following the works of Chaboche +and Roussilier. A back stress α is introduced such that the effective stress is +computed as +𝜎eff = 𝜎eff(𝜎11 − 2𝛼11 − 𝛼22, 𝜎22 − 2𝛼22 − 𝛼11, 𝜎12 − 𝛼12) +The back stress is the sum of up to four terms according to +𝛼𝑖𝑗 = ∑ 𝛼𝑖𝑗 +𝑘=1 +and the evolution of each back stress component is as follows +𝛿𝛼𝑖𝑗 +𝑘 = 𝐶𝑘 (𝑎𝑘 +𝑠𝑖𝑗 +𝜎eff +− 𝛼𝑖𝑗 +𝑘 ) 𝛿𝜀𝑝 +where 𝐶𝑘 and 𝑎𝑘 are material parameters, 𝑠𝑖𝑗 is the deviatoric stress tensor, 𝜎eff is +the effective stress and 𝜀𝑝 is the effective plastic strain. The yield condition is +for this case modified according to +𝑓 (𝛔, 𝛂, 𝜀𝑝) += 𝜎eff(𝜎𝑥𝑥 − 2𝛼𝑥𝑥 − 𝛼𝑦𝑦, 𝜎𝑦𝑦 − 2𝛼𝑦𝑦 − 𝛼𝑥𝑥, 𝜎𝑥𝑦 − 𝛼𝑥𝑦) +− {𝜎𝑌 +𝑡 (𝜀𝑝, 𝜀̇𝑝, 0) − ∑ 𝑎𝑘[1 − exp(−𝐶𝑘𝜀𝑝) ] +} ≤ 0 +𝑘=1 +in order to get the expected stress strain response for uniaxial stress. +4. The Hansel hardening law is the same as in material 113 but is repeated here for +the sake of convenience. +The hardening is temperature dependent and therefore this material model +must be run either in a coupled thermo-mechanical solution, using prescribed +temperatures or using the adiabatic temperature calculation option. Setting the +parameter CP to the specific heat Cp of the material activates the adiabatic tem- +perature calculation that calculates the temperature rate from the equation +𝜎𝐢𝐣𝐷𝑖𝑗 +𝜌𝐶𝑝 +, +𝑇̇ = ∑ +𝑖,𝑗 +where 𝛔: 𝐃𝑝 (the numerator) is the plastically dissipated heat. Using the Kelvin +scale is recommended, even though other scales may be used without prob- +lems. +The hardening behaviour is described by the following equations. The marten- +site rate equation is +∂𝑉𝑚 +∂𝜀̅𝑝 +⎧0 +{{ +⎨ +{{ +⎩ += +𝑉𝑚 +𝑝 ( +1 − 𝑉𝑚 +𝑉𝑚 +) +𝐵+1 +𝐵 [1 − tanh(𝐶 + D × 𝑇)] +𝜀 < 𝐸0(mart) +exp ( +𝑇 − 𝑇𝐴0 +) 𝜀̅𝑝 ≥ 𝐸0(mart) +Where +𝜀̅𝑝 = effective plastic strain +𝑇 = temperature +The martensite fraction is integrated from the above rate equation: +𝑉𝑚 = ∫ +∂𝑉𝑚 +∂𝜀̅𝑝 +𝑑𝜀̅𝑝. +It always holds that 0.0 < 𝑉𝑀 < 1.0. The initial martensite content is Vm0 and +must be greater than zero and less than 1.0. Note that 𝑉𝑀0 is not used during a +restart or when initializing the Vm history variable using *INITIAL_STRESS_- +SHELL. +The yield stress σy is +𝜎𝑦 = {𝐵𝐻𝑆 − (𝐵𝐻𝑆 − 𝐴𝐻𝑆)exp(−𝑚[𝜀̅𝑝 + 𝜀0]𝑛)}(𝐾1 + 𝐾2𝑇) + Δ𝐻𝛾→𝛼′𝑉𝑚. +The parameters p and B should fulfill the following condition +1 + 𝐵 +< 𝑝, +if not fulfilled then the martensite rate will approach infinity as 𝑉𝑚 approaches +zero. Setting the parameter 𝜀0 larger than zero, typical range 0.001-0.02 is rec- +ommended. A part from the effective true strain a few additional history varia- +bles are output, see below. +History variables that are output for post-processing: +Variable Description +24 Yield stress of material at temperature TREF. Useful to evaluate the +strength of the material after e.g., a simulated forming operation. +25 Volume fraction martensite, Vm +26 CP.EQ.0.0: Not used +CP.GT.0.0: Temperature from adiabatic temperature calculation. +5. Heat treatment for increasing the formability of prestrained aluminum sheets +can be simulated through the use of HTFLAG, where the intention is to run a +forming simulation in steps involving preforming, springback, heat treatment +and postforming. In each step the history is transferred to the next via the use +of dynain . The first two steps are per- +formed with HTFLAG = 0 according to standard procedures, resulting in a +0corresponding to the prestrain. The heat treatment step is +plastic strain field 𝜀𝑝 +performed using HTFLAG = 1 in a coupled thermomechanical simulation, +where the blank is heated. The coupling between thermal and mechanical is +only that the maximum temperature 𝑇0 is stored as a history variable in the +material model, this corresponding to the heat treatment temperature. Here it +is important to export all history variables to the dynein file for the postforming +step. In the final postforming step, HTFLAG = 2, the yield stress is then aug- +mented by the Hocket-Sherby like term +0) +Δ𝜎 = 𝑏 − (𝑏 − 𝑎)exp[−𝑐(𝜀𝑝 − 𝜀𝑝 +] +where a, b, c and d are given as tables as functions of the heat treatment temper- +ature 𝑇0 and prestrain 𝜀𝑝 +0. That is, in the table definitions each load curve corre- +sponds to a given prestrain and the load curve value is with respect to the heat +treatment temperature, +𝑎 = 𝑎(𝑇0, 𝜀𝑝 +𝑑 = 𝑑(𝑇0, 𝜀𝑝 +𝑏 = 𝑏(𝑇0, 𝜀𝑝 +𝑐 = 𝑐(𝑇0, 𝜀𝑝 +0) +0), +0), +0), +The effect of heat treatment is that the material strength decreases but harden- +ing increases, thus typically, +𝑎 ≤ 0, +𝑏 ≥ 𝑎, +𝑐 > 0, +𝑑 > 0. +*MAT_134 +This is Material Type 134. The viscoelastic fabric model is a variation on the general +viscoelastic model of material 76. This model is valid for 3 and 4 node membrane +elements only and is strongly recommended for modeling isotropic viscoelastic fabrics +where wrinkling may be a problem. For thin fabrics, buckling can result in an inability +to support compressive stresses; thus, a flag is included for this option. If bending +stresses are important use a shell formulation with model 76. + Card 1 +1 +Variable +MID +Type +I +2 +RO +F +3 +4 +5 +6 +BULK +F +8 +7 +CSE +F +If fitting is done from a relaxation curve, specify fitting parameters on card 2, otherwise +if constants are set on Viscoelastic Constant Cards LEAVE THIS CARD BLANK. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCID +NT +BSTART +TRAMP +LCIDK +NTK +BSTARTK TRAMPK +Type +F +I +F +F +F +I +F +F +Viscoelastic Constant Cards. Up to 6 cards may be input. A keyword card (with a +“*” in column 1) terminates this input if less than 6 cards are used. These cards are not +needed if relaxation data is defined. The number of terms for the shear behavior may +differ from that for the bulk behavior: simply insert zero if a term is not included. + Card 3 +Variable +Type +1 +GI +F +2 +BETAI +F +3 +KI +F +4 +5 +6 +7 +8 +BETAKI +F + VARIABLE +DESCRIPTION +MID +RO +Material identification. A unique number must be specified. +Mass density. +BULK +*MAT_VISCOELASTIC_FABRIC +DESCRIPTION +Elastic constant bulk modulus. +is +viscoelastic, then this modulus is used in determining the contact +interface stiffness only. + If the bulk behavior +CSE +Compressive stress flag (default = 0.0). +EQ.0.0: don’t eliminate compressive stresses +EQ.1.0: eliminate compressive stresses +LCID +NT +BSTART +Load curve ID if constants, Gi, and βi are determined via a least +squares fit. This relaxation curve is shown below. +Number of terms in shear fit. If zero the default is 6. Currently, +the maximum number is set to 6. +In the fit, β1 is set to zero, β2 is set to BSTART, β3 is 10 times β2, +β4 is 10 times β3 , and so on. If zero, BSTART = 0.01. +TRAMP +Optional ramp time for loading. +LCIDK +Load curve ID for bulk behavior if constants, Ki, and βκi are +determined via a least squares fit. This relaxation curve is shown +below. +NTK +Number of terms desired in bulk fit. If zero the default is 6. +Currently, the maximum number is set to 6. +BSTARTK +In the fit, βκ1 is set to zero, βκ2 is set to BSTARTK, βκ3 is 10 +times βκ2, βκ4 + If zero, +BSTARTK = 0.01. +is 10 times βκ3 +, and so on. +TRAMPK +Optional ramp time for bulk loading. +GI +Optional shear relaxation modulus for the ith term +BETAI +Optional shear decay constant for the ith term +KI +Optional bulk relaxation modulus for the ith term +BETAKI +Optional bulk decay constant for the ith term +Remarks: +Rate effects are taken into accounted through linear viscoelasticity by a convolution +integral of the form: +𝜎𝑖𝑗 = ∫ 𝑔𝑖𝑗𝑘𝑙 +(𝑡 − 𝜏) +∂𝜀𝑘𝑙 +∂𝜏 +𝑑𝜏 +where 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) is the relaxation function.If we wish to include only simple rate +effects for the deviatoric stresses, the relaxation function is represented by six terms +from the Prony series: +𝑔(𝑡) = ∑ 𝐺𝑚 +𝑚=1 +𝑒−𝛽𝑚 𝑡 +We characterize this in the input by shear modulii, 𝐺𝑖, and decay constants, 𝛽𝑖. An +arbitrary number of terms, up to 6, may be used when applying the viscoelastic model. +For volumetric relaxation, the relaxation function is also represented by the Prony series +in terms of bulk modulii: +𝑘(𝑡) = ∑ 𝐾𝑚 +𝑚=1 +𝑒−𝛽𝑘𝑚 𝑡 +σ∕ε +TRAMP +10n +10n+1 10n+2 10n+3 +time +optional ramp time for loading +Figure M134-1. Stress Relaxation curve. +For an example of a stress relaxation curve see Figure M134-1. This curve defines stress +versus time where time is defined on a logarithmic scale. For best results, the points +defined in the load curve should be equally spaced on the logarithmic scale. +Furthermore, the load curve should be smooth and defined in the positive quadrant. If +nonphysical values are determined by least squares fit, LS-DYNA will terminate with +an error message after the initialization phase is completed. If the ramp time for +loading is included, then the relaxation which occurs during the loading phase is taken +into account. This effect may or may not be important. +*MAT_135 +This is material type 135. This anisotropic-viscoplastic material model adopts two yield +criteria for metals with orthotropic anisotropy proposed by Barlat and Lian [1989] +(Weak Texture Model) and Aretz [2004] (Strong Texture Model). +5 +6 +7 +8 +NUMFI +EPSC +WC +TAUC + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +E +F +3 +4 +PR +F +4 +F +5 +Variable +SIGMA0 +QR1 +CR1 +QR2 +CR2 +Type +F +F +F +F +F +YLD2003 Card. This card 3 format is used when FLG = 0. + Card 3 +Variable +1 +A1 +Type +F +2 +A2 +F +3 +A3 +F +4 +A4 +F +5 +A5 +F +F +6 +K +F +6 +A6 +F +F +7 +LC +F +7 +A7 +F +F +8 +FLG +F +8 +A8 +F +Yield Surface Card. This card 3 format is used when FLG = 1. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +S00 +S45 +S90 +SBB +R00 +R45 +R90 +RBB +Type +F +F +F +F +F +F +F +YLD89 Card. This card 3 format used when FLG = 2. +5 +6 +7 +8 + Card 3 +Variable +Type +1 +A +F + Card 4 +1 +2 +C +F +2 +3 +H +F +3 +4 +P +F +4 +5 +Variable +QX1 +CX1 +QX2 +CX2 +EDOT +7 +8 +EMIN +S100 +F +7 +F +8 +7 +8 +7 +8 +6 +M +F +6 +6 +A3 +F +6 +D3 +F +F +3 +3 +ZP +F +3 +V3 +F +F +4 +4 +A1 +F +4 +D1 +F +F +5 +5 +A2 +F +5 +D2 +F +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +LS-DYNA R10.0 +Type +F + Card 5 +1 +F +2 +Variable +AOPT +BETA +Type +F +F +2 +YP +F +2 +V2 +F + Card 6 +Variable +1 +XP +Type +F + Card 7 +Variable +1 +V1 +Type +F + VARIABLE +VARIABLE +DESCRIPTION +RO +E +PR +NUMFI +EPSC +WC +TAUC +Mass density +Young’s modulus +Poisson’s ratio +Number of through thickness integration points that must fail +before the element is deleted (remember to change this number if +switching between full and reduced integration type of elements). +Critical value 𝜀𝑡𝐶 of the plastic thickness strain (used in the CTS +fracture criterion). +Critical value 𝑊𝑐 for the Cockcroft-Latham fracture criterion +Critical value 𝜏𝑐 for the Bressan-Williams shear fracture criterion +SIGMA0 +Initial mean value of yield stress 𝜎0: +GT.0.0: Constant value, +LT.0.0: Load curve ID = -SIGMA0 which defines yield stress as +a function of plastic strain. Hardening parameters +QR1, CR1, QR2, and CR2 are ignored in that case. +QR1 +CR1 +QR2 +CR2 +K +LC +A1 +A2 +A3 +Isotropic hardening parameter 𝑄𝑅1 +Isotropic hardening parameter 𝐶𝑅1 +Isotropic hardening parameter 𝑄𝑅2 +Isotropic hardening parameter 𝐶𝑅2 +𝑘 equals half YLD2003 exponent 𝑚. Recommended value for FCC +materials is 𝑚 = 8, i.e. 𝑘 = 4. +First load curve number for process effects, i.e. the load curve +describing the relation between the pre-strain and the yield stress +𝜎0. Similar curves for 𝑄𝑅1, 𝐶𝑅1, 𝑄𝑅2, 𝐶𝑅2, and 𝑊𝑐 must follow +consecutively from this number. +Yld2003 parameter 𝑎1 +Yld2003 parameter 𝑎2 +Yld2003 parameter 𝑎3 +*MAT_WTM_STM +DESCRIPTION +A4 +A5 +A6 +A7 +A8 +S00 +S45 +S90 +SBB +R00 +R45 +R90 +RBB +A +C +H +P +QX1 +CX1 +QX2 +CX2 +Yld2003 parameter 𝑎4 +Yld2003 parameter 𝑎5 +Yld2003 parameter 𝑎6 +Yld2003 parameter 𝑎7 +Yld2003 parameter 𝑎8 +Yield stress in 0° direction +Yield stress in 45° direction +Yield stress in 90° direction +Balanced biaxial flow stress +R-ratio in 0° direction +R-ratio in 45° direction +R-ratio in 90° direction +Balance biaxial flow ratio +YLD89 parameter a +YLD89 parameter c +YLD89 parameter h +YLD89 parameter p +Kinematic hardening parameter 𝑄𝑥1 +Kinematic hardening parameter 𝐶𝑥1 +Kinematic hardening parameter 𝑄𝑥2 +Kinematic hardening parameter 𝐶𝑥2 +EDOT +Strain rate parameter 𝜀̇0 +M +Strain rate parameter 𝑚 +EMIN +*MAT_135 +DESCRIPTION +Lower limit of the isotropic hardening rate 𝑑𝑅 +𝑑𝜀̅. This feature is +included to model a non-zero and linear/exponential isotropic +work hardening rate at large values of effective plastic strain. If +the isotropic work hardening rate predicted by the utilized Voce- +type work hardening rule falls below the specified value it is +substituted by the prescribed value or switched to a power-law +hardening if S100.NE.0. This option should be considered for +problems involving extensive plastic deformations. If process +dependent material characteristics are prescribed, i.e. if LC .GT. +0 the same minimum tangent modulus is assumed for all the +prescribed work hardening curves. If instead EMIN.LT.0 then – +EMIN defines the plastic strain value at which the linear or +power-law hardening approximation commences. +S100 +AOPT +Yield stress at 100% strain for using a power-law approximation +beyond the strain defined by EMIN. +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the shell ele- +ment normal by an angle BETA. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later.. +BETA +Material angle in degrees for AOPT = 0 or 3, may be overwritten +on the element card, see *ELEMENT_SHELL_BETA. +XP YP ZP +Coordinates of point p for AOPT = 1. +*MAT_WTM_STM +DESCRIPTION +A1 A2 A3 +Components of vector a for AOPT = 2. +V1 V2 V3 +Components of vector v for AOPT = 3 +D1 D2 D3 +Components of vector d for AOPT = 2. +Remarks: +If FLG = 1, i.e. if the yield surface parameters 𝑎1−𝑎8 are identified on the basis of +prescribed material data internally in the material routine, files with point data for +plotting of the identified yield surface, along with the predicted directional variation of +the yield stress and plastic flow are generated in the directory where the LS-DYNA +analysis is run. Four different files are generated for each specified material. +These files are named according to the scheme: +1. Contour_1# +2. Contour_2# +3. Contour_3# +4. R_and_S# +Where # is a value starting at 1. +The three first files contain contour data for plotting of the yield surface as shown in +Figure M135-2. To generate these plots a suitable plotting program should be adopted +and for each file/plot, column A should be plotted vs. columns B. For a more detailed +description of these plots it is referred to References. Figure M135-3 further shows a +plot generated from the final file named ‘R_and_S#’ showing the directional +dependency of the normalized yield stress (column A vs. B) and plastic strain ratio +(column B vs. C). +The yield condition for this material can be written +𝑡(σ, α, 𝜀𝑝, 𝜀̇𝑝) = 𝜎eff(σ, α) − 𝜎𝑌(𝜀𝑝, 𝜀̇𝑝) +where +𝜎𝑌 = [𝜎0 + 𝑅(𝜀𝑝)] (1 + +) +𝜀̇𝑝 +𝜀̇0 +where the isotropic hardening reads +𝑅(𝜀̇𝑝) = 𝑄𝑅1[1 − exp(−𝐶𝑅1𝜀𝑝)] + 𝑄𝑅2[1 − exp(−𝐶𝑅2𝜀𝑝)]. +For the Weak Texture Model the yield function is defined as +𝜎eff = [ +{𝑎(𝑘1 + 𝑘2)𝑚 + 𝑎(𝑘1 − 𝑘2)𝑚 + 𝐶(2𝑘2)𝑚}] +where +𝑘1 = +𝜎𝑥 + ℎ 𝜎𝑦 +√ +√√ +⎷ +( +𝜎𝑥 + ℎ 𝜎𝑦 +) +𝑘2 = ++ (𝑟 𝜎𝑥𝑦) +. +For the Strong Texture Model the yield function is defined as +𝜎eff = { +where +[(𝜎+ +′ )𝑚 + (𝜎− +′ )𝑚 + (𝜎+ +′′ − 𝜎− +′′)𝑚]} +′ = +σ± +𝑎8𝜎𝑥 + 𝑎1𝜎𝑦 +± √( +𝑎2𝜎𝑥 − 𝑎3𝜎𝑦 +) ++ 𝑎4 +2𝜎𝑥𝑦 +2 +′′ = +σ± +𝜎𝑥 + 𝜎𝑦 +± √( +𝑎5𝜎𝑥 − 𝑎6𝜎𝑦 +) ++ 𝑎7 +2 𝜎𝑥𝑦. +Kinematic hardening can be included by +α = ∑ α𝑅 +𝑅=1 +where each of the kinematic hardening variables 𝛼𝑅 is independent and obeys a +nonlinear evolutionary equation in the form +where the effective stress 𝜎̅̅̅̅̅ is defined as +α̇𝑅 = 𝐶𝛼𝑖 (𝑄𝛼𝑖 +− α𝑅) 𝜀̇𝑝 +where +𝜎̅̅̅̅̅ = 𝜎eff(τ) +τ = σ − α. +Critical thickness strain failure in a layer is assumed to occur when +𝜀𝑡 ≤ 𝜀𝑡𝑐 +where 𝜀𝑡𝑐 is a material parameter. It should be noted that 𝜀𝑡𝑐 is a negative number (i.e. +failure is assumed to occur only in the case of thinning). +Cockcraft and Latham fracture is assumed to occur when +where 𝜎1 is the maximum principal stress and 𝑊𝐶 is a material parameter. +𝑊 = ∫ max(𝜎1, 0)𝑑𝜀𝑝 ≥ 𝑊𝐶 +History +Variable +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +11 +12 +13 +14 +Description +Isotropic hardening value 𝑅1 +Isotropic hardening value 𝑅2 +Increment in effective plastic strain Δ𝜀̅ +Not defined, for internal use in the material model +Not defined, for internal use in the material model +Not defined, for internal use in the material model +Failure in integration point +EQ.0: No failure +EQ.1: Failure due to EPSC, i.e. 𝜀𝑡 ≥ 𝜀𝑡𝑐. +EQ.2: Failure due to WC, i.e. 𝑊 ≥ 𝑊𝑐. +EQ.3: Failure due to TAUC, i.e. 𝜏 ≥ 𝜏𝑐 +Sum of +incremental strain +𝜀𝑥𝑥 = ∑ Δ𝜀𝑥𝑥 +Sum of +𝜀𝑦𝑦 = ∑ Δ𝜀𝑦𝑦 +incremental strain +in +in +local element x-direction: +local element y-direction: +Value of theh Cockcroft-Latham failure parameter 𝑊 = ∑ 𝜎1Δ𝑝 +Plastic strain component in thickness direction 𝜀𝑡 +Mean value of increments in plastic strain through the thickness +(For use with the non-local instability criterion. Note that +constant lamella thickness is assumed and the instability +criterion can give unrealistic results if used with a user-defined +integration rule with varying lamella thickness.) +Not defined, for internal use in the material model +Nonlocal value 𝜌 = +Δ𝜀3 +Ω +Δ𝜀3 +Table M135-1. +1.5 +0.5 +-0.5 +-1 +-1.5 +-1.5 +-1 +-0.5 +1.5 +0.75 +xy +-0.75 +-1.5 +0.5 +1.5 +-1.5 +-0.75 +(A) +1.5 +0.75 +xy +-0.75 +-1.5 +0.75 +1.5 +√2(σ +x+σ +2σ +y) +(B) +0.75 +1.5 +-1.5 +-0.75 +√2(σ +x-σ +2σ +y) +(C) +Figure M135-2. Contour plots of the yield surface generated from the files (a) +‘Contour_1<#>’, (b) Contour_2<#>’, and (c) ‘Contour_3<#>’. +1.1 +1.05 +σα +0.95 +1.6 +1.2 +0.8 +0.4 +Rα +0.9 +30 +α [deg] +60 +90 +Figure M135-3. Predicted directional variation of the yield stress and plastic +flow generated from the file ‘R_and_S<#>’. +*MAT_135_PLC +This is Material Type 135. This anisotropic material adopts the yield criteria proposed +by Aretz [2004]. The material strength is defined by McCormick’s constitutive relation +for materials exhibiting negative steady-state Strain Rate Sensitivity (SRS). McCormick +[1998] and Zhang, McCormick and Estrin [2001]. +5 +6 +7 +8 +NUMFI +EPSC +WC +TAUC + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +E +F +3 +4 +PR +F +4 +F +5 +Variable +SIGMA0 +QR1 +CR1 +QR2 +CR2 +Type +F +F +F +F +F + Card 3 +Variable +1 +A1 +Type +F + Card 4 +Variable +Type +1 +S +F +2 +A2 +F +2 +H +F +3 +A3 +F +3 +4 +A4 +F +4 +5 +A5 +F +5 +OMEGA +TD +ALPHA +EPS0 +F +F +F +F +F +6 +K +F +6 +A6 +F +6 +F +7 +7 +A7 +F +7 +F +8 +8 +A8 +F +Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +AOPT +BETA +Type +F +F + Card 6 +Variable +1 +XP +Type +F + Card 7 +Variable +1 +V1 +Type +F +2 +YP +F +2 +V2 +F +3 +ZP +F +3 +V3 +F +4 +A1 +F +4 +D1 +F +5 +A2 +F +5 +D2 +F +6 +A3 +F +6 +D3 +F +7 +8 +7 +8 + VARIABLE +DESCRIPTION +MID +RO +E +PR +NUMFI +EPSC +WC +TAUC +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus +Poisson’s ratio +Number of through thickness integration points that must fail +before the element is deleted (remember to change this number if +switching between full and reduced integration type of elements). +Critical value 𝜀𝑡𝐶 of the plastic thickness strain. +Critical value 𝑊𝑐 for the Cockcroft-Latham fracture criterion. +Critical value 𝜏𝑐 for the shear fracture criterion. +SIGMA0 +Initial yield stress 𝜎0 +VARIABLE +DESCRIPTION +QR1 +CR1 +QR2 +CR2 +K +A1 +A2 +A3 +A4 +A5 +A6 +A7 +A8 +S +H +Isotropic hardening parameter, 𝑄𝑅1 +Isotropic hardening parameter, 𝐶𝑅1 +Isotropic hardening parameter, 𝑄𝑅2 +Isotropic hardening parameter, 𝐶𝑅2 +k equals half the exponent m for the yield criterion +Yld2003 parameter, 𝑎1 +Yld2003 parameter, 𝑎2 +Yld2003 parameter, 𝑎3 +Yld2003 parameter, 𝑎4 +Yld2003 parameter, 𝑎5 +Yld2003 parameter, 𝑎6 +Yld2003 parameter, 𝑎7 +Yld2003 parameter, 𝑎8 +Dynamic strain aging parameter, S. +Dynamic strain aging parameter, H. +OMEGA +Dynamic strain aging parameter, Ω. +TD +Dynamic strain aging parameter, 𝑡𝑑. +ALPHA +Dynamic strain aging parameter, 𝛼. +EPS0 +AOPT +Dynamic strain aging parameter, 𝜀̇0. +Material axes option +EQ.0.0: Locally orthotropic with material axes determined by +element nodes as shown in Figure M2-1, and then ro- +tated about the shell element normal by the angle BE- +TA. Nodes 1, 2 and 4 of an element are identical to the +nodes used for the definition of a coordinate system as +by *DEFINE_COORDINATE_NODES. +VARIABLE +DESCRIPTION +EQ.2.0: Globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: Locally orthotropic material axes determined by +offsetting the material axes by an angle, BETA, from a +line determined by taking the cross product of the vec- +tor v with the normal to the plane of the element. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +BETA +Material angle in degrees for AOPT = 0 and 3, may be overwritten +on the element card, see *ELEMENT_SHELL_BETA. +XP, YP, ZP +Coordinates of point p for AOPT = 1. +A1, A2, A3 +Components of vector a for AOPT = 2. +V1, V2, V3 +Components of vector v for AOPT = 3. +D1, D2, D3 +Components of vector d for AOPT = 2. +Remarks: +The yield function is defined as +𝑓 = 𝑓 ̅(σ) − [𝜎𝑌(𝑡𝑎) + 𝑅(𝜀𝑝) + 𝜎𝑣(𝜀̇𝑝)] +where the equivalent stress 𝜎eq is defined as by an anisotropic yield criterion +𝜎eq = [ +(∣𝜎′1∣𝑚 + ∣𝜎′2∣𝑚 + ∣𝜎′′1 − 𝜎′′2∣)] +where +and +{ +𝜎′1 +𝜎′2 +} = +𝑎8𝜎𝑥𝑥 + 𝑎1𝜎𝑦𝑦 +± √( +𝑎2𝜎𝑥𝑥 − 𝑎3𝜎𝑦𝑦 +) ++ 𝑎4 +2𝜎𝑥𝑦 +2 +𝜎′′1 +{ +𝜎′′2 +} = +𝜎𝑥𝑥 + 𝜎𝑦𝑦 +± √( +𝑎5𝜎𝑥𝑥 − 𝑎6𝜎𝑦𝑦 +) ++ 𝑎7 +2𝜎𝑥𝑦 +The strain hardening function R is defined by the extended Voce law +𝑅(𝜀𝑝) = ∑ 𝑄𝑅𝑖(1 − exp(−𝐶𝑅𝑖𝜀𝑝)) +𝑖=1 +where 𝜀𝑝 is the effective (or accumulated) plastic strain, and 𝑄𝑅𝑖and 𝐶𝑅𝑖 are strain +hardening parameters. +Viscous stress 𝜎𝑣 is given by +𝜎𝑣 = (𝜀̇𝑝) = 𝑠 ln (1 + +𝜀̇𝑝 +𝜀̇0 +) +where S represents the instantaneous strain rate sensitivity (SRS) and 𝜀̇0 is a reference +strain rate. In this model the yield strength, including the contribution from dynamic +strain aging (DSA) is defined as +𝜎𝑌(𝑡𝑎) = 𝜎0 + SH [1 − exp {− ( +) +𝑡𝑎 +𝑡𝑑 +}] +where 𝜎0is the yield strength for vanishing average waiting time, 𝑡𝑎, i.e. at high strain +rates, and H, 𝛼and 𝑡𝑑 are material constants linked to dynamic strain aging. It is +noteworthy that 𝜎𝑌 is an increasing function of 𝑡𝑎. The average waiting time is defined +by the evolution equation +𝑡 ̇𝑎 = 1 − +𝑡𝑎 +𝑡𝑎,𝑠���� +where the quasi-steady waiting time 𝑡𝑎,𝑠𝑠 is given as +𝑡𝑎,𝑠𝑠 = +𝜀̇𝑝 +where Ω is the strain produced by all mobile dislocations moving to the next obstacle +on their path. +*MAT_CORUS_VEGTER +This is Material Type 136, a plane stress orthotropic material model for metal forming. +Yield surface construction is based on the interpolation by second-order Bezier curves, +and model parameters are determined directly from a set of mechanical tests conducted +for a number of directions. For each direction, four mechanical tests are carried out: a +uniaxial, an equi-biaxial, a plane strain tensile test and a shear test. These test results +are used to determine the coefficients of the Fourier directional dependency field. For a +more detailed description please see Vegter and Boogaard [2006]. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +E +F +3 +4 +PR +F +4 +5 +N +F +5 +Variable +SYS +SIP +SHS +SHL +ESH +Type +F + Card 3 +1 +Variable +AOPT +Type + Card 4 +Variable +1 +XP +Type +F +F +2 +2 +YP +F +F +3 +3 +ZP +F +F +4 +4 +A1 +F +F +5 +5 +A2 +F +6 +FBI +F +6 +E0 +F +6 +6 +A3 +F +7 +8 +RBI0 +LCID +F +7 +F +8 +ALPHA +LCID2 +F +7 +F +8 +7 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +*MAT_136 +7 +8 +BETA +F +Experimental Data Cards. The next N cards contain experimental data +obtained from four mechanical tests for a group of equidistantly placed directions +𝜃𝑖 = 𝑖𝜋 +2𝑁 , 𝑖 = 0, 1, 2, … , 𝑁. + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FUN-I +RUN-I +FPS1-I +FPS2-I +FSH-I +Type +F +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +N +FBI +RBI0 +LCID +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Material density +Elastic Young’s modulus +Poisson’s ratio +|N| is order of Fourier series (i.e., number of test groups minus +one). The minimum number for |N| is 2, and the maximum is 12. +GE.0.0: Explicit cutting-plane return mapping algorithm +LT.0.0: Fully implicit return mapping algorithm (more robust) +Normalized yield stress 𝜎𝑏𝑖 for equi-biaxial test. +Strain ratio 𝜌𝑏𝑖(0°) = 𝜀̇2(0°)/𝜀̇1(0°) for equi-biaxial test in the +rolling direction. +Stress-strain curve ID. If defined, SYS, SIP, SHS, SHL, ESH, and +E0 are ignored. +SYS +Static yield stress, 𝜎0. +SIP +SHS +SHL +ESH +E0 +ALPHA +LCID2 +*MAT_CORUS_VEGTER +DESCRIPTION +Stress increment parameter, Δ𝜎𝑚. +Strain hardening parameter for small strain, 𝛽. +Strain hardening parameter for larger strain, Ω. +Exponent for strain hardening, n. +Initial plastic strain, 𝜀0 +𝛼 distribution of hardening used in the curve-fitting. 𝛼 = 0 pure +kinematic hardening and 𝛼 = 1 provides pure +isotropic +hardening. +Curve ID. The curve defines Young’s modulus scaling factor +with respect to the plastic strain. By default it is assumed that +Young’s modulus remains constant. Effective value is between 0 +and 1. +AOPT +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the shell ele- +ment normal by the angle BETA. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). +XP, YP, ZP +Coordinates of point p for AOPT = 1. +A1, A2, A3 +Components of vector a for AOPT = 2. +V1, V2, V3 +Components of vector v for AOPT = 3 +Figure M136-1. Bézier interpolation curve. + VARIABLE +DESCRIPTION +D1, D2, D3 +Components of vector d for AOPT = 2. +Material angle in degrees for AOPT = 0 and 3, may be overwritten +on the element card, see *ELEMENT_SHELL_BETA. +Normalized yield stress 𝜎un for uniaxial test for the ith direction. +Strain ratio (R-value) for uniaxial test for the ith direction. +First normalized yield stress 𝜎ps1 for plain strain test for the ith +direction. +Second normalized yield stress 𝜎ps2 for plain strain test for the ith +direction. +First normalized yield stress 𝜎sh for pure shear test for the ith +direction. +BETA +FUN-I +RUN-I +FPS1-I +FPS2-I +FSH-I +Remarks: +The Vegter yield locus is section-wise defined by quadratic Bézier interpolation +functions. Each individual curve uses 2 reference points and a hinge point in the +principal plane stress space, see Figure M136-1. +The mathematical description of the Bézier interpolation is given by: +Figure M136-2. Vegter yield surface. +𝜎1 +( +𝜎2 +) = ( +𝜎1 +𝜎2 +) ++ 2𝜇 [( +𝜎1 +𝜎2 +− ( +𝜎1 +𝜎2 +) +) +] + 𝜇2 [( +𝜎1 +𝜎2 ++ ( +𝜎1 +𝜎2 +) +− 2( +) +𝜎1 +𝜎2 +] +) +where (𝜎1, 𝜎2)0 is the first reference point, (𝜎1, 𝜎2)1 is the hinge point, and (𝜎1, 𝜎2)2 is +the second reference point. 𝜇 is a parameter which determines the location on the curve +(0 ≤ 𝜇 ≤ 1). +Four characteristic stress states are selected as reference points: the equi-biaxial point +(𝜎𝑏𝑖, 𝜎𝑏𝑖), the plane strain point (𝜎𝑝𝑠1, 𝜎𝑝𝑠2), the uniaxial point (𝜎𝑢𝑛, 0) and the pure +shear point (𝜎𝑠ℎ, −𝜎𝑠ℎ), see Figure M136-2. Between the 4 stress points, 3 Bézier curves +are used to interpolate the yield locus. Symmetry conditions are used to construct the +complete surface. The yield locus in Figure M136-2 shows the reference points of +experiments for one specific direction. The reference points can also be determined for +other angles to the rolling direction (planar angle 𝜃). E.g. if N = 2 is chosen, normalized +yield stresses for directions 0°, 45°, and 90° should be defined. A Fourier series is used +to interpolate intermediate angles between the measured points. +The Vegter yield function with isotropic hardening (ALPHA = 1) is given as: +𝜙 = 𝜎𝑒𝑞(𝜎1, 𝜎2, 𝜃) − 𝜎𝑦(𝜀̅𝑝) +with the equivalent stress 𝜎𝑒𝑞 obtained from the appropriate Bézier function related to +the current stress state. The uni-axial yield stress 𝜎𝑦 can be defined as stress-strain +curve LCID or alternatively as a functional expression: +𝜎𝑦 = 𝜎0 + Δ𝜎𝑚[𝛽(𝜀̅𝑝 + 𝜀0) + (1 − 𝑒−Ω(𝜀̅𝑝+𝜀0)) +] +In case of kinematic hardening (ALPHA < 1), the standard stress tensor is replaced by a +relative stress tensor, defined as the difference between the stress tensor and a back +stress tensor. +To determine the yield stress or reference points of the Vegter yield locus, four +mechanical tests have to be performed for different directions. A good description +about the material characterization procedure can be found in Vegter et al. (2003). +*MAT_COHESIVE_MIXED_MODE +This is Material Type 138. This model is a simplification of *MAT_COHESIVE_GENER- +AL restricted to linear softening. It includes a bilinear traction-separation law with +quadratic mixed mode delamination criterion and a damage formulation. This material +model can be used only with cohesive element fomulations; see the variable ELFORM +in *SECTION_SOLID and *SECTION_SHELL. +6 +ET +F +6 +7 +8 +GIC +GIIC +F +7 +F +8 + Card 1 +1 +2 +3 +4 +5 +Variable +MID +RO +ROFLG +INTFAIL +EN +Type +A8 + Card 2 +1 +Variable +XMU +Type +F + VARIABLE +MID +F +2 +T +F +F +3 +S +F +F +4 +F +5 +UND +UTD +GAMMA +F +F +F +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +ROFLG +INTFAIL +EN +ET +Flag for whether density is specified per unit area or volume. +ROFLG = 0 specified density per unit volume (default), and +ROFLG = 1 specifies the density is per unit area for controlling +the mass of cohesive elements with an initial volume of zero. +The number of integration points required for the cohesive +element to be deleted. If it is zero, the element will not be deleted +even if it satisfies the failure criterion. The value of INTFAIL may +range from 1 to 4, with 1 the recommended value. +The stiffness (units of stress / length) normal to the plane of the +cohesive element. +The stiffness (units of stress / length) in the plane of the cohesive +element. +VARIABLE +DESCRIPTION +GIC +GIIC +XMU +T +S +UND +UTD +Energy release rate for mode I (units of stress × length) +Energy release rate for mode II (units of stress × length) +Exponent of the mixed mode criteria +Peak traction (stress units) in normal direction +LT.0.0: Load curve ID = (-T) which defines peak traction in +normal direction as a function of element size. See re- +marks. +Peak traction (stress units) in tangential direction +LT.0.0: Load curve ID = (-S) which defines peak traction in +tangential direction as a function of element size. See +remarks. +Ultimate displacement in the normal direction +Ultimate displacement in the tangential direction +GAMMA +Additional exponent for Benzeggagh-Kenane law (default = 1.0) +Remarks: +The ultimate displacements +in the normal and tangential directions are the +displacements at the time when the material has failed completely, i.e., the tractions are +zero. The linear stiffness for loading followed by the linear softening during the +damage provides an especially simple relationship between the energy release rates, the +peak tractions, and the ultimate displacements: +GIC = T × +GIIC = S × +UND +UTD +If the peak tractions aren’t specified, they are computed from the ultimate displace- +ments. See Fiolka and Matzenmiller [2005] and Gerlach, Fiolka and Matzenmiller +[2005]. +In this cohesive material model, the total mixed-mode relative displacement 𝛿𝑚 is +2 , where 𝛿𝐼 = 𝛿3 is the separation in normal direction (mode I) +defined as 𝛿𝑚 = √𝛿𝐼 +2 + 𝛿𝐼𝐼 +3 +2 +1 +II +traction +0δ +II +II +Fδ +Figure M138-1. Mixed-mode traction-separation law +and 𝛿𝐼𝐼 = √𝛿1 +damage initiation displacement 𝛿0 (onset of softening) is given by +2 is the separation in tangential direction (mode II). The mixed-mode +2 + 𝛿2 +𝛿0 = 𝛿𝐼 +0𝛿𝐼𝐼 +0 √ +1 + 𝛽2 +0 )2 + (𝛽𝛿𝐼 +(𝛿𝐼𝐼 +0)2 +0 = 𝑇/EN and 𝛿𝐼𝐼 +0 = 𝑆/ET are the single mode damage inititation separations +where 𝛿𝐼 +and 𝛽 = 𝛿𝐼𝐼/𝛿𝐼 is the “mode mixity” . The ultimate mixed-mode +displacement 𝛿𝐹 (total failure) for the power law (XMU > 0) is: +⎡( +⎢ +⎣ +and alternatively for the Benzeggagh-Kenane law [1996] (XMU < 0): +𝛿𝐹 = ++ ( +) +) +2(1 + 𝛽2) +𝛿0 +ET × 𝛽2 +GIIC +EN +GIC +XMU +XMU +XMU +− 1 +⎤ +⎥ +⎦ +𝛿𝐹 = +𝛿0 ( 1 +1 + 𝛽2 EN𝛾 + +1/𝛾 +𝛽2 +1 + 𝛽2 ET𝛾) +⎡GIC + (GIIC − GIC) ( +⎢ +⎣ +𝛽2 × ET +EN + 𝛽2 × ET +) +|XMU| +⎤ +⎥ +⎦ +A reasonable choice for the exponent 𝛾 would be GAMMA = 1.0 (default) or +GAMMA = 2.0. +In this model, damage of the interface is considered, i.e. irreversible conditions are +enforced with loading/unloading paths coming from/pointing to the origin. +Peak tractions 𝑇 and/or 𝑆 can be defined as functions of characteristic element length +(square root of midsurface area) via load curve. This option is useful to get nearly the +same global responses (e.g. load-displacement curve) with coarse meshes when +compared to a fine mesh solution. In general, lower peak traction values are needed for +coarser meshes +QMAX +GC +Displacement +Figure M138-2. Bilinear traction-separation +Two error checks have been implemented for this material model in order to ensure +proper material data. Since the traction versus displacement curve is fairly simple +(triangular shaped), equations can be developed to ensure that the displacement, 𝐿, at +the peak load (QMAX), is smaller than the ultimate distance for failure, 𝑢. See Figure +M138-2 for the used notation. +One has that +And, +GC = +𝑢 × QMAX +𝐿 = +QMAX +. +To ensure that the peak is not past the failure point, 𝑢 +𝐿 must be larger than 1. +2GC +EL +where GC is the energy release rate. This gives +𝑢 = +, += +2GC +EL × 𝐿 += +2GC +𝐸 ( +QMAX +2 > 1. +) +The error checks are then done for tension and pure shear, respectively, += +(2GIC) +EN( 𝑇 +EN +2 > 1, +) += +(2GIIC) +ET ( 𝑆 +ET +) +2 > 1. +*MAT_MODIFIED_FORCE_LIMITED +This is Material Type 139. This material for the Belytschko-Schwer resultant beam is an +extension of material 29. In addition to the original plastic hinge and collapse +mechanisms of material 29, yield moments may be defined as a function of axial force. +After a hinge forms, the moment transmitted by the hinge is limited by a moment- +plastic rotation relationship. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +DF +F +6 +7 +8 +AOPT +YTFLAG +ASOFT +F +F +F +Default +none +none +none +none +0.0 +0.0 +0.0 +0.0 + Card 2 +1 +Variable +M1 +Type +F +Default +none + Card 3 +1 +2 +M2 +F +0 +2 +3 +M3 +F +0 +3 +4 +M4 +F +0 +4 +5 +M5 +F +0 +5 +6 +M6 +F +0 +6 +7 +M7 +F +0 +7 +8 +M8 +F +0 +8 +Variable +LC1 +LC2 +LC3 +LC4 +LC5 +LC6 +LC7 +LC8 +Type +F +Default +none +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LPS1 +SFS1 +LPS2 +SFS2 +YMS1 +YMS2 +Type +Default +F +0 +F +F +F +F +F +1.0 +LPS1 +1.0 +1.0E+20 YMS1 + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LPT1 +SFT1 +LPT2 +SFT2 +YMT1 +YMT2 +Type +Default +F +0 +F +F +F +F +F +1.0 +LPT1 +1.0 +1.0E+20 YMT1 + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LPR +SFR +YMR +Type +Default +F +0 +F +F +1.0 +1.0E+20 + Card 7 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LYS1 +SYS1 +LYS2 +SYS2 +LYT1 +SYT1 +LYT2 +SYT2 +Type +Default +F +0 +F +1.0 +F +0 +F +1.0 +F +0 +F +1.0 +F +0 +F +1.0 +Card 8 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LYR +SYR +Type +Default +F +0 +F +1.0 + Card 9 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +HMS1_1 HMS1_2 HMS1_3 HMS1_4 HMS1_5 HMS1_6 HMS1_7 HMS1_8 +Type +Default +F +0 + Card 10 +1 +F +0 +2 +F +0 +3 +F +0 +4 +F +0 +5 +F +0 +6 +F +0 +7 +F +0 +8 +Variable +LPMS1_1 LPMS1_2 LPMS1_3 LPMS1_4 LPMS1_5 LPMS1_6 LPMS1_7 LPMS1_8 +Type +Default +F +0 + Card 11 +1 +F +0 +2 +F +0 +3 +F +0 +4 +F +0 +5 +F +0 +6 +F +0 +7 +F +0 +8 +Variable +HMS2_1 HMS2_2 HMS2_3 HMS2_4 HMS2_5 HMS2_6 HMS2_7 HMS2_8 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +Card 12 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LPMS2_1 LPMS2_2 LPMS2_3 LPMS2_4 LPMS2_5 LPMS2_6 LPMS2_7 LPMS2_8 +Type +Default +F +0 + Card 13 +1 +F +0 +2 +F +0 +3 +F +0 +4 +F +0 +5 +F +0 +6 +F +0 +7 +F +0 +8 +Variable +HMT1_1 HMT1_2 HMT1_3 HMT1_4 HMT1_5 HMT1_6 HMT1_7 HMT1_8 +Type +Default +F +0 + Card 14 +1 +F +0 +2 +F +0 +3 +F +0 +4 +F +0 +5 +F +0 +6 +F +0 +7 +F +0 +8 +Variable +LPMT1_1 LPMT1_2 LPMT1_3 LPMT1_4 LPMT1_5 LPMT1_6 LPMT1_7 LPMT1_8 +Type +Default +F +0 + Card 15 +1 +F +0 +2 +F +0 +3 +F +0 +4 +F +0 +5 +F +0 +6 +F +0 +7 +F +0 +8 +Variable +HMT2_1 HMT2_2 HMT2_3 HMT2_4 HMT2_5 HMT2_6 HMT2_7 HMT2_8 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +Card 16 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LPMT2_1 LPMT2_2 LPMT2_3 LPMT2_4 LPMT2_5 LPMT2_6 LPMT2_7 LPMT2_8 +Type +Default +F +0 + Card 17 +1 +F +0 +2 +F +0 +3 +F +0 +4 +F +0 +5 +F +0 +6 +F +0 +7 +F +0 +8 +Variable +HMR_1 +HMR_2 +HMR_3 +HMR_4 +HMR_5 +HMR_6 +HMR_7 +HMR_8 +Type +Default +F +0 + Card 18 +1 +F +0 +2 +F +0 +3 +F +0 +4 +F +0 +5 +F +0 +6 +F +0 +7 +F +0 +8 +Variable +LPMR_1 +LPMR_2 +LPMR_3 +LPMR_4 +LPMR_5 +LPMR_6 +LPMR_7 +LPMR_8 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +DF +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus +Poisson’s ratio +Damping factor, see definition in notes below. A proper control +for the timestep has to be maintained by the user! +*MAT_MODIFIED_FORCE_LIMITED +DESCRIPTION +AOPT +Axial load curve option: +EQ.0.0: axial load curves are force versus strain, +EQ.1.0: axial load curves are force versus change in length. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +YTFLAG +Flag to allow beam to yield in tension: +EQ.0.0: beam does not yield in tension, +EQ.1.0: beam can yield in tension. +ASOFT +M1, M2, +…, M8 +LC1, LC2, +…, LC8 +LPS1 +SFS1 +LPS2 +SFS2 +YMS1 +Axial elastic softening factor applied once hinge has formed. +When a hinge has formed the stiffness is reduced by this factor. If +zero, this factor is ignored. +Applied end moment for force versus (strain/change in length) +curve. At least one must be defined. A maximum of 8 moments +can be defined. The values should be in ascending order. +Load curve ID defining axial force versus +strain/change in length for the corresponding +applied end moment. Define the same number as end moments. +Each curve must contain the same number of points. +Load curve ID for plastic moment versus rotation about s-axis at +node 1. If zero, this load curve is ignored. +Scale factor for plastic moment versus rotation curve about s-axis +at node 1. Default = 1.0. +Load curve ID for plastic moment versus rotation about s-axis at +node 2. Default: is same as at node 1. +Scale factor for plastic moment versus rotation curve about s-axis +at node 2. Default: is same as at node 1. +Yield moment about s-axis at node 1 for interaction calculations +(default set to 1.0E+20 to prevent interaction). +VARIABLE +DESCRIPTION +YMS2 +LPT1 +SFT1 +LPT2 +SFT2 +YMT1 +YMT2 +LPR +SFR +YMR +LYS1 +SYS1 +LYS2 +SYS2 +LYT1 +Yield moment about s-axis at node 2 for interaction calculations +(default set to YMS1). +Load curve ID for plastic moment versus rotation about t-axis at +node 1. If zero, this load curve is ignored. +Scale factor for plastic moment versus rotation curve about t-axis +at node 1. Default = 1.0. +Load curve ID for plastic moment versus rotation about t-axis at +node 2. Default: is the same as at node 1. +Scale factor for plastic moment versus rotation curve about t-axis +at node 2. Default: is the same as at node 1. +Yield moment about t-axis at node 1 for interaction calculations +(default set to 1.0E+20 to prevent interactions) +Yield moment about t-axis at node 2 for interaction calculations +(default set to YMT1) +Load curve ID for plastic torsional moment versus rotation. If +zero, this load curve is ignored. +Scale factor for plastic torsional moment versus rotation +(default = 1.0). +Torsional yield moment for interaction calculations (default set to +1.0E+20 to prevent interaction) +ID of curve defining yield moment as a function of axial force for +the s-axis at node 1. +Scale factor applied to load curve LYS1. +ID of curve defining yield moment as a function of axial force for +the s-axis at node 2. +Scale factor applied to load curve LYS2. +ID of curve defining yield moment as a function of axial force for +the t-axis at node 1. +SYT1 +Scale factor applied to load curve LYT1. +LYT2 +SYT2 +LYR +*MAT_MODIFIED_FORCE_LIMITED +DESCRIPTION +ID of curve defining yield moment as a function of axial force for +the t-axis at node 2. +Scale factor applied to load curve LYT2. +ID of curve defining yield moment as a function of axial force for +the torsional axis. +SYR +Scale factor applied to load curve LYR. +HMS1_n +Hinge moment for s-axis at node 1. +LPMS1_n +ID of curve defining plastic moment as a function of plastic +rotation for the s-axis at node 1 for hinge moment HMS1_n +HMS2_n +Hinge moment for s-axis at node 2. +LPMS2_n +ID of curve defining plastic moment as a function of plastic +rotation for the s-axis at node 2 for hinge moment HMS2_n +HMT1_n +Hinge moment for t-axis at node 1. +LPMT1_n +ID of curve defining plastic moment as a function of plastic +rotation for the t-axis at node 1 for hinge moment HMT1_n +HMT2_n +Hinge moment for t-axis at node 2. +LPMT2_n +ID of curve defining plastic moment as a function of plastic +rotation for the t-axis at node 2 for hinge moment HMT2_n +HMR_n +Hinge moment for the torsional axis. +LPMR_n +ID of curve defining plastic moment as a function of plastic +rotation for the torsional axis for hinge moment HMR_n +Remarks: +This material model is available for the Belytschko resultant beam element only. Plastic +hinges form at the ends of the beam when the moment reaches the plastic moment. The +plastic moment versus rotation relationship is specified by the user in the form of a load +curve and scale factor. The points of the load curve are (plastic rotation in radians, +plastic moment). Both quantities should be positive for all points, with the first point +being (zero, initial plastic moment). Within this constraint any form of characteristic +may be used, including flat or falling curves. Different load curves and scale factors +may be specified at each node and about each of the local s and t axes. +Axial collapse occurs when the compressive axial load reaches the collapse load. +Collapse load versus collapse deflection is specified in the form of a load curve. The +points of the load curve are either (true strain, collapse force) or (change in length, +collapse force). Both quantities should be entered as positive for all points, and will be +interpreted as compressive. The first point should be (zero, initial collapse load). +The collapse load may vary with end moment as well as with deflections. In this case +several load-deflection curves are defined, each corresponding to a different end +moment. Each load curve should have the same number of points and the same +deflection values. The end moment is defined as the average of the absolute moments +at each end of the beam and is always positive. +Stiffness-proportional damping may be added using the damping factor λ. This is +defined as follows: +𝜆 = +2 × 𝜉 +where ξ is the damping factor at the reference frequency ω (in radians per second). For +example if 1% damping at 2Hz is required +𝜆 = +2 × 0.01 +2𝜋 × 2 += 0.001592 +If damping is used, a small time step may be required. LS-DYNA does not check this so +to avoid instability it may be necessary to control the time step via a load curve. As a +guide, the time step required for any given element is multiplied by 0.3L⁄cλ when +damping is present (L = element length, c = sound speed). +Moment Interaction: +Plastic hinges can form due to the combined action of moments about the three axes. +This facility is activated only when yield moments are defined in the material input. A +hinge forms when the following condition is first satisfied. +where, +⎜⎛ 𝑀𝑟 +⎟⎞ +𝑀𝑟yield⎠ +⎝ ++ +⎜⎛ 𝑀𝑠 +⎟⎞ +𝑀𝑠yield⎠ +⎝ ++ +⎜⎛ 𝑀𝑡 +⎟⎞ +𝑀𝑡yield⎠ +⎝ +≥ 1 +𝑀𝑟, 𝑀𝑠, 𝑀𝑡, = current moment +𝑀𝑟yield, 𝑀𝑠yield, 𝑀𝑡yield = yield moment +Note that scale factors for hinge behavior defined in the input will also be applied to the +yield moments: for example, Msyield in the above formula is given by the input yield +moment about the local axis times the input scale factor for the local s axis. For strain- +softening characteristics, the yield moment should generally be set equal to the initial +peak of the moment-rotation load curve. +On forming a hinge, upper limit moments are set. These are given by +⎜⎛𝑀𝑟, +⎝ +and similar conditions hold for 𝑀𝑠𝑢𝑝𝑝𝑒𝑟and 𝑀𝑡𝑢𝑝𝑝𝑒𝑟. Thereafter the plastic moments will +be given by +𝑀𝑟upper = max +⎟⎞ +2 ⎠ +𝑀𝑟yield +𝑀𝑟𝑝 = min(𝑀𝑟upper, 𝑀𝑟curve) +where, +𝑀𝑟p = current plastic moment +𝑀𝑟curve = moment from load curve at the current rotation scaled by the scale factor. +𝑀𝑠𝑝and 𝑀𝑡𝑝 satisfy similar conditions. +The effect of this is to provide an upper limit to the moment that can be generated; it +represents the softening effect of local buckling at a hinge site. Thus if a member is bent +about is local s-axis it will then be weaker in torsion and about its local t-axis. For +moments-softening curves, the effect is to trim off the initial peak (although if the +curves subsequently harden, the final hardening will also be trimmed off). +It is not possible to make the plastic moment vary with the current axial load, but it is +possible to make hinge formation a function of axial load and subsequent plastic +moment a function of the moment at the time the hinge formed. This is discussed in the +next section. +Independent plastic hinge formation: +In addition to the moment interaction equation, Cards 7 through 18 allow plastic hinges +to form independently for the s-axis and t-axis at each end of the beam and also for the +torsional axis. A plastic hinge is assumed to form if any component of the current +moment exceeds the yield moment as defined by the yield moment vs. axial force +curves input on cards 7 and 8. If any of the 5 curves is omitted, a hinge will not form +for that component. The curves can be defined for both compressive and tensile axial +forces. If the axial force falls outside the range of the curve, the first or last point in the +curve will be used. A hinge forming for one component of moment does not effect the +other components. +Upon forming a hinge, the magnitude of that component of moment will not be +permitted to exceed the current plastic moment.. The current plastic moment is +obtained by interpolating between the plastic moment vs. plastic rotation curves input +on cards 10, 12, 14, 16, or 18. Curves may be input for up to 8 hinge moments, where +the hinge moment is defined as the yield moment at the time that the hinge formed. +Curves must be input in order of increasing hinge moment and each curve should have +the same plastic rotation values. The first or last curve will be used if the hinge moment +falls outside the range of the curves. If no curves are defined, the plastic moment is +obtain from the curves on cards 4 through 6. The plastic moment is scaled by the scale +factors on lines 4 to 6. +A hinge will form if either the independent yield moment is exceeded or if the moment +interaction equation is satisfied. If both are true, the plastic moment will be set to the +minimum of the interpolated value and Mrp. +M8 +M7 +M6 +M5 +M4 +M3 +M2 +M1M1 +Strain (or change in length, see AOPT) +Figure M139-1. The force magnitude is limited by the applied end moment. +For an intermediate value of the end moment LS-DYNA interpolates between +the curves to determine the allowable force value. +*MAT_VACUUM +This is Material Type 140. This model is a dummy material representing a vacuum in a +multi-material Euler/ALE model. Instead of using ELFORM = 12 (under *SECTION_- +SOLID), it is better to use ELFORM = 11 with the void material defined as vacuum +material instead. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +RHO +Type +A8 +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RHO +Estimated material density. This is used only as stability check. +Remarks: +1. The vacuum density is estimated. It should be small relative to air in the model +(possibly at least 103 to 106 lighter than air). +*MAT_RATE_SENSITIVE_POLYMER +This is Material Type 141. This model, called the modified Ramaswamy-Stouffer +model, is for the simulation of an isotropic ductile polymer with strain rate effects. See +references; Stouffer and Dame [1996] and Goldberg and Stouffer [1999]. Uniaxial test +data is used to fit the material parameters. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +Variable +Omega +Type +F + VARIABLE +MID +RO +E +PR +Do +N +Zo +q +2 +RO +F +2 +3 +E +F +3 +4 +PR +F +4 +5 +Do +F +5 +6 +N +F +6 +7 +Zo +F +7 +8 +q +F +8 +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Elastic modulus. +Poisson's ratio +Reference strain rate (= 1000 × max strain rate used in the test). +Exponent +Initial hardness of material +. +Omega +Maximum internal stress. +The inelastic strain rate is defined as: +*MAT_RATE_SENSITIVE_POLYMER +𝐼 = 𝐷𝑜 exp +𝜀̇𝑖𝑗 +⎡−0.5 ( +⎢ +⎣ +𝑍𝑜 +3𝐾2 +) +𝑆𝑖𝑗 − Ω𝑖𝑗 +⎟⎞ +√𝐾2 ⎠ +⎤ +⎥ +⎦ +⎜⎛ +⎝ +where the 𝐾2 term is given as: +𝐾2 = 0.5(𝑆𝑖𝑗 − Ω𝑖𝑗)(𝑆𝑖𝑗 − Ω𝑖𝑗) +and represents the second invariant of the overstress tensor. The elastic components of +the strain are added to the inelastic strain to obtain the total strain. The following +relationship defines the back stress variable rate: +Ω𝑖𝑗 = +𝑞Ω𝑚𝜀̇𝑖𝑗 +𝐼 − 𝑞Ω𝑖𝑗𝜀̇𝑒 +𝐼 +where 𝑞 is a material constant, Ω𝑚 is a material constant that represents the maximum +value of the internal stress, and 𝜀̇𝑒 +𝐼 is the effective inelastic strain rate. +*MAT_TRANSVERSELY_ISOTROPIC_CRUSHABLE_FOAM +This is Material Type 142. This model is for an extruded foam material that is +transversely isotropic, crushable, and of low density with no significant Poisson effect. +This material is used in energy-absorbing structures to enhance automotive safety in +low velocity (bumper impact) and medium high velocity (interior head impact and +pedestrian safety) applications. The formulation of this foam is due to Hirth, Du Bois, +and Weimar and is documented by Du Bois [2001]. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +4 +5 +6 +E11 +E22 +E12 +E23 +F +3 +F +4 +F +5 +F +6 +7 +G +F +7 +8 +K +F +8 +Variable +I11 +I22 +I12 +I23 +IAA +NSYM +ANG +MU +Type +I + Card 3 +1 +I +2 +I +3 +Variable +AOPT +ISCL +MACF +Type +F +I +I + Card 4 +Variable +1 +XP +Type +F +2 +YP +F +3 +ZP +F +I +4 +4 +A1 +F +I +5 +5 +A2 +F +I +6 +6 +A3 +F +F +7 +F +8 +7 +Variable +1 +D1 +Type +F + VARIABLE +MID +*MAT_TRANSVERSELY_ISOTROPIC_CRUSHABLE_FOAM +2 +D2 +F +3 +D3 +F +4 +V1 +F +5 +V2 +F +6 +V3 +F +7 +8 +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +E11 +E22 +E12 +E23 +G +K +I11 +I22 +I12 +I23 +Mass density +Elastic modulus in axial direction. +Elastic modulus in transverse direction (E22 = E33). +Elastic shear modulus (E12 = E31). +Elastic shear modulus in transverse plane. +Shear modulus. +Bulk modulus for contact stiffness. +Load curve for nominal axial stress versus volumetric strain. +Load curve ID for nominal transverse stresses versus volumetric +strain (I22 = I33). +Load curve ID for shear stress component 12 and 31 versus +volumetric strain (I12 = I31). +Load curve ID for shear stress component 23 versus volumetric +strain. +IAA +NSYM +Load curve ID (optional) for nominal stress versus volumetric +strain for load at angle, ANG, relative to the material 𝑎-axis. +Set to unity for a symmetric yield surface in volumetric +compression and tension direction. +ANG +Angle corresponding to load curve ID, IAA. +VARIABLE +MU +DESCRIPTION +Damping coefficient for tensor viscosity which acts in both +tension and compression. Recommended values vary between +0.05 to 0.10. If zero, tensor viscosity is not used, but bulk viscosity +is used instead. Bulk viscosity creates a pressure as the element +compresses that is added to the normal stresses, which can have +the effect of creating transverse deformations when none are +expected. +AOPT +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes as shown in Figure M2-1. Nodes 1, 2, +and 4 of an element are identical to the nodes used for +the definition of a coordinate system as by *DEFINE_- +COORDINATE_NODES. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the a-direction. This option is for solid +elements only. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. The plane of a solid element is the +midsurface between the inner surface and outer sur- +face defined by the first four nodes and the last four +nodes of the connectivity of the element, respectively. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector v, and +an originating point, P, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +ISCL +*MAT_TRANSVERSELY_ISOTROPIC_CRUSHABLE_FOAM +DESCRIPTION +Load curve ID for the strain rate scale factor versus the +volumetric strain rate. The yield stress is scaled by the value +specified by the load curve. +MACF +Material axes change flag: +EQ.1: No change, default, +EQ.2: switch material axes 𝐚 and 𝐛, +EQ.3: switch material axes 𝐚 and 𝐜, +EQ.4: switch material axes 𝐛 and 𝐜. +XP YP ZP +Coordinates of point 𝐩 for AOPT = 1 and 4. +A1 A2 A3 +Components of vector 𝐚 for AOPT = 2. +D1 D2 D3 +Components of vector 𝐝 for AOPT = 2. +V1 V2 V3 +Define components of vector v for AOPT = 3 and 4. +Remarks: +This model behaves in a more physical way for off axis loading the material than, for +example, *MAT_HONEYCOMB which can exhibit nonphysical stiffening for loading +conditions that are off axis. The curves given for I11, I22, I12 and I23 are used to define +a yield surface of Tsai-Wu-type that bounds the deviatoric stress tensor. Hence the +elastic parameters E11, E12, E22 and E23 as well as G and K have to be defined in a +consistent way. +The link ed image cannot be display ed. The file may hav e been mov ed, renamed, or deleted. Verify that the link points to the correct file and location. + Figure M142-1. Differences between options NSYM = 1 and NSYM = 0. +For the curve definitions volumetric strain 𝜀𝑣 = 1 − 𝑉/𝑉0 is used as the abscissa +parameter. If the symmetric option (NSYM = 1) is used, a curve for the first quadrant +has to be given only. If NSYM = 0 is chosen, the curve definitions for I11, I22, I12 and +I23 (and IAA) have to be in the first and second quadrant as shown in Figure M142-1. +Tensor viscosity, which is activated by a nonzero value for MU, is generally more stable +than bulk viscosity. A damping coefficient less than 0.01 has little effect, and a value +greater than 0.10 may cause numerical instabilities. +*MAT_WOOD +This is Material Type 143. This is a transversely isotropic material and is available for +solid elements. The user has the option of inputting his or her own material properties +(), or requesting default material properties for Southern yellow pine (PINE) +or Douglas fir (FIR). This model was developed by Murray [2002] under a contract +from the FHWA. +Available options include: + +PINE +FIR + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +RO +NPLOT +ITERS +IRATE +GHARD +IFAIL +IVOL +Type +A8 +F +I +I +I +F +I +I +Card 2 for PINE and FIR keyword options. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MOIS +TEMP +QUAL_T QUAL_C +UNITS +IQUAL +Type +F +F +F +F +I +I +The following cards 2 through 6 are for option left blank. + Card 2 +Variable +1 +EL +Type +F +2 +ET +F +3 +4 +GLT +GTR +F +F +5 +PR +F +6 +7 +Variable +1 +XT +Type +F + Card 4 +1 +2 +XC +F +2 +3 +YT +F +3 +4 +YC +F +4 +*MAT_143 +5 +6 +7 +8 +SXY +SYZ +F +5 +F +6 +7 +8 +Variable +GF1|| +GF2|| +BFIT +DMAX|| +GF1┴ +GF2┴ +DFIT +DMAX┴ +Type +F + Card 5 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +FLPAR +FLPARC +POWPAR +FLPER +FLPERC +POWPER +Type +F + Card 6 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +7 +8 +Variable +NPAR +CPAR +NPER +CPER +Type +F +F +F +F +The remaining cards all keyword options. + Card 7 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +AOPT +MACF +BETA +Type +F +I +Variable +1 +XP +Type +F + Card 9 +Variable +1 +D1 +Type +F + VARIABLE +MID +*MAT_WOOD +7 +8 +7 +8 +2 +YP +F +2 +D2 +F +3 +ZP +F +3 +D3 +F +4 +A1 +F +4 +V1 +F +5 +A2 +F +5 +V2 +F +6 +A3 +F +6 +V3 +F +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +NPLOT +Controls what is written as component 7 to the d3plot database. +LS-PrePost always blindly labels this component as effective +plastic strain.: +EQ.1: Parallel damage (default). +EQ.2: Perpendicular damage. +ITERS +Number of plasticity algorithm iterations. The default is one +iteration. +IRATE +Rate effects option: +EQ.0: Rate effects model turned off (default). +EQ.1: Rate effects model turned on. +GHARD +Perfect plasticity override. Values greater than or equal to zero +are allowed. Positive values model late time hardening in +compression (an increase in strength with increasing strain). A +zero value models perfect plasticity (no increase in strength with +increasing strain). The default is zero. +IFAIL +Erosion perpendicular to the grain. +EQ.0: No (default). +EQ.1: Yes (not recommended except for debugging). +IVOL +Flag to invoke erosion based on negative volume or strain +increments greater than 0.01. +EQ.0: No, do not apply erosion criteria. +EQ.1: Yes, apply erosion criteria. +MOIS +TEMP +QUAL_T +Percent moisture content. If left blank, moisture content defaults +to saturated at 30%. +Temperature in ˚C. If left blank, temperature defaults to room +temperature at 20 ˚C +Quality factor options. These quality factors reduce the clear +wood tension, shear, and compression strengths as a function of +grade. +EQ.0: Grade 1, 1D, 2, 2D. +Predefined strength reduction factors are: +Pine: QUAL_T = 0.47 in tension/shear. + QUAL_C = 0.63 in compression. +Fir: +QUAL_T = 0.40 in tension/shear + QUAL_C = 0.73 in compression. +EQ.-1: DS-65 or SEl STR (pine and fir). +Predefined strength reduction factors are: + QUAL_T = 0.80 in tension/shear. + QUAL_C = 0.93 in compression. +EQ.-2: Clear wood. +No strength reduction factors are applied: + QUAL_T = 1.0. + QUAL_C = 1.0. +GT.0: User defined quality factor in tension. Values between +0 and 1 are expected. Values greater than one are al- +lowed, but may not be realistic. +QUAL_C +User defined quality factor in compression. This input value is +used if Qual_T > 0. Values between 0 and 1 are expected. Values +greater than one are allowed, but may not be realistic. If left +blank, a default value of Qual_C = Qual_T is used. +UNITS +Units options: +EQ.0: GPa, mm, msec, Kg/mm3, kN. +EQ.1: MPa, mm, msec, g/mm3, Nt. +EQ.2: MPa, mm, sec, Mg/mm3, Nt. +EQ.3: Psi, inch, sec, lb-s2/inch4, lb +IQUAL +Apply quality factors perpendicular to the grain: +EQ.0: Yes (default). +EQ.1: No. +Parallel normal modulus +Perpendicular normal modulus. +Parallel shear modulus (GLT = GLR). +Perpendicular shear modulus. +Parallel major Poisson's ratio. +Parallel tensile strength. +Parallel compressive strength. +Perpendicular tensile strength. +Perpendicular compressive strength. +Parallel shear strength. +Perpendicular shear strength. +EL +ET +GLT +GTR +PR +XT +XC +YT +YC +SXY +SYZ +GF1|| +GF2|| +Parallel fracture energy in tension. +Parallel fracture energy in shear. +BFIT +Parallel softening parameter. +DMAX|| +Parallel maximum damage. +Perpendicular fracture energy in tension. +Perpendicular fracture energy in shear. +GF1┴ +GF2┴ +DFIT +Perpendicular softening parameter. +DMAX┴ +Perpendicular maximum damage. +FLPAR +Parallel fluidity parameter for tension and shear. +FLPARC +Parallel fluidity parameter for compression. +POWPAR +Parallel power. +FLPER +Perpendicular fluidity parameter for tension and shear. +FLPERC +Perpendicular fluidity parameter for compression. +POWPER +Perpendicular power. +NPAR +Parallel hardening initiation. +CPAR +NPER +CPER +AOPT +Parallel hardening rate +Perpendicular hardening initiation. +Perpendicular hardening rate. +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes as shown in Figure M2-1. Nodes 1, 2, +and 4 of an element are identical to the nodes used for +the definition of a coordinate system as by *DEFINE_- +COORDINATE_NODES. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the a-direction. This option is for solid +elements only. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. The plane of a solid element is the +midsurface between the inner surface and outer surface +defined by the first four nodes and the last four nodes +of the connectivity of the element, respectively. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector v, and +an originating point, P, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +MACF +Material axes change flag: +EQ.1: No change, default, +EQ.2: switch material axes a and b, +EQ.3: switch material axes a and c, +EQ.4: switch material axes b and c. +BETA +Material angle in degrees for AOPT = 3, may be overridden on +the element card, see *ELEMENT_SOLID_ORTHO. +XP YP ZP +Coordinates of point p for AOPT = 1 and 4. +A1 A2 A3 +Components of vector a for AOPT = 2. +D1 D2 D3 +Components of vector d for AOPT = 2. +V1 V2 V3 +Define components of vector v for AOPT = 3 and 4. +Remarks: +Material property data is for clear wood (small samples without defects like knots), +whereas real structures are composed of graded wood. Clear wood is stronger than +graded wood. Quality factors (strength reduction factors) are applied to the clear wood +strengths to account for reductions in strength as a function of grade. One quality factor +(QUAL_T) is applied to the tensile and shear strengths. A second quality factor +(QUAL_C) is applied to the compressive strengths. As a option, predefined quality +factors are provided based on correlations between LS-DYNA calculations and test data +for pine and fir posts impacted by bogie vehicles. By default, quality factors are applied +to both the parallel and perpendicular to the grain strengths. An option is available +(IQUAL) to eliminate application perpendicular to the grain. +*MAT_PITZER_CRUSHABLE_FOAM +This is Material Type 144. This model is for the simulation of isotropic crushable forms +with strain rate effects. Uniaxial and triaxial test data have to be used. For the elastic +response, the Poisson ratio is set to zero. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +K +F +3 +Variable +LCPY +LCUYS +LCSR +Type +I +I +I +6 +TY +F +6 +7 +8 +SRTV +F +7 +8 +4 +G +F +4 +VC +F +5 +PR +F +5 +DFLG +F +DESCRIPTION + VARIABLE +MID +RO +K +G +PR +TY +SRTV +LCPY +LCUYS +LCSR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Bulk modulus. +Shear modulus +Poisson's ratio +Tension yield. +Young’s modulus (E) +Load curve ID giving pressure versus volumetric strain, see +Figure M75-1. +Load curve ID giving uniaxial stress versus volumetric strain, see +Figure M75-1. +Load curve ID giving strain rate scale factor versus volumetric +strain rate. +*MAT_PITZER_CRUSHABLE_FOAM +DESCRIPTION +VC +Viscous damping coefficient (.05 < recommended value < .50). +DFLG +Density flag: +EQ.0.0: use initial density +EQ.1.0: use current density (larger step size with less mass +scaling). +Remarks: +The logarithmic volumetric strain is defined in terms of the relative volume, 𝑉, as: +𝛾 = −ln(𝑉) +In defining the curves the stress and strain pairs should be positive values starting with +a volumetric strain value of zero. +*MAT_SCHWER_MURRAY_CAP_MODEL +This is Material Type 145. *MAT_145 is a Continuous Surface Cap Model and is a three +invariant extension of *MAT_GEOLOGIC_CAP_MODEL (*MAT_025) that includes +viscoplasticity for rate effects and damage mechanics to model strain softening. The +primary references for the model are Schwer and Murray [1994], Schwer [1994], and +Murray and Lewis [1994]. *MAT_145 was developed for geomaterials including soils, +concrete, and rocks. It is recommended that an updated version of a Continuous +Surface Cap Model, *MAT_CSCM (*MAT_159), be used rather than *MAT_SCHWER_- +MURRAY_CAP_MODEL (*MAT_145). +Warning: no default input parameter values are assumed, but recommendations for the +more obscure parameters are provided in the descriptions that follow. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +RO +SHEAR +BULK +GRUN +SHOCK +PORE +Type +A8 + Card 2 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +8 +Variable +ALPHA +THETA +GAMMA +BETA +EFIT +FFIT +ALPHAN +CALPHA +Type +F +F + Card 3 +1 +Variable +RO +Type +F + Card 4 +Variable +Type +1 +W +F +2 +XO +F +2 +D1 +F +F +3 +F +4 +F +5 +F +6 +F +7 +IROCK +SECP +AFIT +BFIT +RDAMO +F +3 +D2 +F +F +4 +F +5 +F +6 +F +7 +NPLOT +EPSMAX +CFIT +DFIT +TFAIL +F +F +F +F +F +F +8 +Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FAILFL +DBETA +DDELTA +VPTAU +Type +F + Card 6 +1 +F +2 +F +3 +F +4 +5 +6 +7 +8 +Variable +ALPHA1 +THETA1 GAMMA1 +BETA1 +ALPHA2 +THETA2 GAMMA2 +BETA2 +Type +F +F +F +F +F +F +F +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +SHEAR +Shear modulus, G +BULK +Bulk modulus, K +GRUN +Gruneisen ratio (typically = 0), Γ +SHOCK +Shock velocity parameter (typically 0), Sl +PORE +Flag for pore collapse +EQ.0.0: for Pore collapse +EQ.1.0: for Constant bulk modulus (typical) +ALPHA +Shear failure parameter, 𝛼 +THETA +Shear failure parameter, 𝜃 +GAMMA +Shear failure parameter, 𝛾 +BETA +Shear failure parameter, 𝛽 +√𝐽′2 = 𝐹𝑒(𝐽1) = 𝛼 − 𝛾exp(−𝛽𝐽1) + 𝜃𝐽1 +EFIT +Dilitation damage mechanics parameter (no damage = 1) +VARIABLE +DESCRIPTION +FFIT +Dilitation damage mechanics parameter (no damage = 0) +ALPHAN +Kinematic strain hardening parameter, 𝑁𝛼 +CALPHAN +Kinematic strain hardening parameter, 𝑐𝛼 +R0 +X0 +Initial cap surface ellipticity, R +Initial cap surface 𝐽1 (mean stress) axis intercept, 𝑋(𝜅0) +IROCK +EQ.0: soils (cap can contract) +EQ.1: rock/concrete +Shear enhanced compaction +Ductile damage mechanics parameter (=1 no damage) +Ductile damage mechanics parameter (=0 no damage) +SECP +AFIT +BFIT +RDAM0 +Ductile damage mechanics parameter +W +D1 +D2 +Plastic Volume Strain parameter, W +Plastic Volume Strain parameter, D1 +Plastic Volume Strain parameter, D2 +NPLOT +EPSMAX +CFIT +DFIT +𝑃 = 𝑊{1 − exp{−𝐷1[𝑋(𝜅) − 𝑋(𝜅0)] − 𝐷2[(𝑋(𝜅) − 𝑋(𝜅0)]2}} +𝜀𝑉 +History variable post-processed as effective plastic strain + +Maximum permitted strain increment (default = 0) +Δ𝜀max = 0.05(𝛼 − 𝑁𝛼 − 𝛾)min( 1 +9𝐾) (calculated default) +𝐺, 𝑅 +Brittle damage mechanics parameter (=1 no damage) +Brittle damage mechanics parameter (=0 no damage) +TFAIL +Tensile failure stress +FAILFL +*MAT_SCHWER_MURRAY_CAP_MODEL +DESCRIPTION +Flag controlling element deletion and effect of damage on stress +: +EQ.1: 𝜎𝑖𝑗 reduces with increasing damage; element is deleted +when fully damaged (default) +EQ.-1: 𝜎𝑖𝑗 reduces with increasing damage; element is not +deleted +EQ.2: 𝑆𝑖𝑗 reduces with increasing damage; element is deleted +when fully damaged +EQ.-2: 𝑆𝑖𝑗 reduces with increasing damage; element is not +deleted +DBETA +Rounded vertices parameter, Δ𝛽0 +DDELTA +Rounded vertices parameter, 𝛿 +VPTAU +Viscoplasticity relaxation time parameter, 𝜏 +ALPHA1 +Torsion scaling parameter, 𝛼1 +𝛼1 < 0 → |𝛼1| = Friction Angle (degrees) +THETA1 +Torsion scaling parameter, 𝜃1 +GAMMA1 +Torsion scaling parameter, 𝛾1 +BETA1 +Torsion scaling parameter, 𝛽1 +𝑄1 = 𝛼1 − 𝛾1exp(−𝛽1𝐽1) + 𝜃1𝐽1𝜃2 +ALPHA2 +Tri-axial extension scaling parameter, 𝛼2 +THETA2 +Tri-axial extension scaling parameter,𝜃2 +GAMMA2 +Tri-axial extension scaling parameter, 𝛾2 +BETA2 +Tri-axial extension scaling parameter, 𝛽2 +𝑄2 = 𝛼2 − 𝛾2exp(−𝛽2𝐽1) + 𝜃2𝐽1 +Remarks: +1. FAILFL controls whether the damage accumulation applies to either the total +stress tensor𝜎𝑖𝑗or the deviatoric stress tensor𝑆𝑖𝑗. When FAILFL = 2, damage +does not diminish the ability of the material to support hydrostatic stress. +2. FAILFL also serves as a flag to control element deletion. Fully damaged +elements are deleted only if FAILFL is a positive value. When MAT_145 is used +with the ALE or EFG solvers, failed elements should not be eroded and so a +negative value of FAILFL should be used. +Output History Variables: +All the output parameters listed in Table M145-1 is available for post-processing using +LS-PrePost and its displayed list of History Variables. The LS-DYNA input parameter +NEIPH should be set to 26; see for example the keyword input for *DATABASE_EX- +TENT_BINARY. +PLOT +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +11 +12 +13 +14 +15 +16 +17 +18 +19 +20 +21 +22 +23 +24 +25 +26 +Function +𝑋(𝜅) +𝐿(𝜅) +𝑅 +𝑅̃ +𝑝 +𝜀𝜈 +𝐺𝛼 +𝛼 +𝐽2 +𝛽 +d +Description +𝐽1 intercept of cap surface +𝐽1value at cap-shear surface intercept +Cap surface ellipticity +Rubin function +Plastic volume strain +Yield Flag ( = 0 elastic) +Number of strain sub-increments +Kinematic hardening parameter +Kinematic hardening back stress +Effective strain rate +Ductile damage +Ductile damage threshold +Strain energy +Brittle damage +Brittle damage threshold +Brittle energy norm +𝐽1 (w/o visco-damage/plastic) +𝐽′2 (w/o visco-damage/plastic) +𝐽′3 (w/o visco-damage/plastic) +𝐽 ̂3(w/o visco-damage/plastic) +Lode Angle +Maximum damage parameter +future variable +future variable +future variable +future variable +Table M145-1. Output variables for post-processing using NPLOT parameter. +*MAT_SCHWER_MURRAY_CAP_MODEL +Gran and Senseny [1996] report the axial stress versus strain response for twelve +unconfined compression tests of concrete, used in scale-model reinforced-concrete wall +tests. The Schwer & Murray Cap Model parameters provided below were used, see +Schwer [2001], to model the unconfined compression test stress-strain response for the +nominal 40 MPa strength concrete reported by Gran and Senseny. The basic units for +the provided parameters are length in millimeters (mm), time in milliseconds (msec), +and mass in grams (g). This base unit set yields units of force in Newtons (N) and +pressure in Mega-Pascals (MPa). +Example MAT_SCHWER_MURRAY_CAP_MODEL deck + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +RO +SHEAR +BULK +GRUN +SHOCK +PORE +Value +A8 +2.3E-3 1.048E4 1.168E4 +0.0 +0.0 +1. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ALPHA +THETA +GAMMA +BETA +EFIT +FFIT +ALPHAN +CALPHA +Value +190.0 +0.0 +184.2 +2.5E-3 +0.999 +0.7 +2.5 +2.5E3 + Card 3 +Variable +1 +R0 +2 +X0 +3 +4 +5 +6 +7 +8 +IROCK +SECP +AFIT +BFIT +RDAM0 +Value +5.0 +100.0 +1.0 +0.0 +0.999 +0.3 +0.94 + Card 4 +Variable +1 +W +2 +D1 +3 +D2 +4 +5 +6 +7 +8 +NPLOT +EPSMAX +CFIT +DFIT +TFAIL +Value +5.0E-2 2.5E-4 3.5E-7 +23.0 +0.0 +1.0 +300.0 +7.0 +Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FAILFG +DBETA +DDELTA +VPTAU +Value +1.0 +0.0 +0.0 +0.0 + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ALPHA1 +THETA1 GAMMA1 +BETA1 +ALPHA2 +THETA2 GAMMA2 +BETA2 +Value +0.747 +3.3E-4 +0.17 +5.0E-2 +0.66 +4.0E-4 +0.16 +5.0E-2 +User Input Parameters and System of Units +Consider the following basic units: +Length: 𝐿 (e.g. millimeters - mm ) +Mass: M (e.g. grams - g ) +Time: T (e.g. milliseconds - ms ) +The following consistent unit systems can then be derived using Newton's Law, i.e. +𝐹 = 𝑀𝑎. +Force: 𝐹 = 𝑀𝐿/𝑇2 [ g-mm/ms 2= Kg-m/s 2= Newton - N ] +Stress: 𝜎 = 𝐹/L2 [ N/mm 2 = 10 6N/m 2 = 10 6 Pascals = MPa ] +Density: ρ = M/L3 [ g/mm 3 = 10 6 Kg/m 3 ] +User Inputs and Units + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +RO +SHEAR +BULK +GRUN +SHOCK +PORE +Units +I +Density +M/L3 +Stress: +F/L2 +Stress: +F/L2 +Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ALPHA +THETA +GAMMA +BETA +EFIT +FFIT +ALPHAN +CALPHA +Units +Stress: +F/L2 +Stress: +F/L2 +Stress-1: +L2/F +Stress-½: +L/F½ +Stress: +F/L2 +Stress: +F/L2 + Card 3 +Variable +1 +R0 +2 +X0 +3 +4 +5 +6 +7 +8 +IROCK +SECP +AFIT +BFIT +RDAM0 +Units +Stress: +F/L2 +Stress-½: +L/F½ +Stress½: +F½/L + Card 4 +Variable +1 +W +2 +D1 +3 +D2 +4 +5 +6 +7 +8 +NPLOT MAXEPS +CFIT +DFIT +TFAIL +Units +Stress-1: +L2/F +Stress-2: +L4/F2 +Stress-½: +L/F½ +Stress: +F/L2 + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FAILFG +DBETA +DDELTA +VPTAU +Units +Angle +degrees +Time T + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ALPHA1 +THETA1 GAMMA1 +BETA1 +ALPHA2 +THETA2 GAMMA2 +BETA2 +Units +Stress: +F/L2 +Stress: +F/L2 +Stress-1: +L2/F +Stress: +F/L2 +Stress: +F/L2 +Stress-1: +L2/F +*MAT_1DOF_GENERALIZED_SPRING +This is Material Type 146. This is a linear spring or damper that allows different +degrees-of-freedom at two nodes to be coupled. +3 +K +F +3 +4 +C +F +4 +5 +6 +7 +8 +SCLN1 +SCLN2 +DOFN1 +DOFN2 +F +5 +F +6 +I +7 +I +8 + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +Variable +CID1 +CID2 +Type +I +I + VARIABLE +DESCRIPTION +MID +RO +K +C +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density, see also volume in *SECTION_BEAM definition. +Spring stiffness. +Damping constant. +SCLN1 +Scale factor on force at node 1. Default = 1.0. +SCLN2 +Scale factor on force at node 2. Default = 1.0. +DOFN1 +DOFN2 +Active degree-of-freedom at node 1, a number between 1 to 6 +where 1 is x-translation and 4 is x-rotation. If this parameter is +defined in the SECTION_BEAM definition or on the ELEMENT_- +BEAM_SCALAR card, then the value here, if defined, is ignored. +Active degree-of-freedom at node 2, a number between 1 to 6. If +this parameter is defined in the SECTION_BEAM definition or on +the ELEMENT_BEAM_SCALAR card, then the value here, if +defined, is ignored. +CID1 +*MAT_1DOF_GENERALIZED_SPRING +DESCRIPTION +Local coordinate system at node 1. This coordinate system can be +overwritten by a local system specified on the *ELEMENT_- +BEAM_SCALAR or *SECTION_BEAM keyword input. If no +coordinate system is specified, the global system is used. +CID2 +Local coordinate system at node 2. If CID2 = 0, CID2 = CID1. +*MAT_147 +This is Material Type 147. This is an isotropic material with damage and is available for +solid elements. The model has a modified Mohr-Coulomb surface to determine the +pressure dependent peak shear strength. It was developed for applications involving +roadbase soils by Lewis [1999] for the FHWA, who extended the work of Abbo and +Sloan [1995] to include excess pore water effects. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +RO +NPLOT +SPGRAV RHOWAT +VN +GAMMAR +INTRMX +Type +A8 +F +Default +none +none + Card 2 +Variable +Type +1 +K +F +2 +G +F +I +1 +3 +F +F +F +F +none +1.0 +0.0 +0.0 +4 +5 +6 +7 +PHIMAX +AHYP +COH +ECCEN +AN +I +1 +8 +ET +F +F +F +F +Default +none +none +none +none +none +none +none +none + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable MCONT +PWD1 +PWKSK +PWD2 +PHIRES +DINT +VDFM +DAMLEV +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +0.0 +none +none +none +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EPSMAX +Type +F +Default +none + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +NPLOT +Controls what is written as component 7 to the d3plot database. +LS-PrePost always blindly labels this component as effective +plastic strain. +EQ.1: Effective Strain +EQ.2: Damage Criterion Threshold +EQ.3: Damage (diso) +EQ.4: Current Damage Criterion +EQ.5: Pore Water Pressure +EQ.6: Current Friction Angle (phi) +SPGRAV +Specific Gravity of Soil used to get porosity. +RHOWATt +Density of water in model units - used to determine air void +strain (saturation) +VN +Viscoplasticity parameter (strain-rate enhanced strength) +GAMMAr +Viscoplasticity parameter (strain-rate enhanced strength) +ITERMAXx +Maximum number of plasticity iterations (default 1) +K +G +Bulk Modulus (non-zero) +Shear modulus (non-zero) +PHIMAX +Peak Shear Strength Angle (friction angle) (radians) +VARIABLE +DESCRIPTION +AHYP +Coefficient A for modified Drucker-Prager Surface +COH +Cohesion ñ Shear Strength at zero confinement (overburden) +ECCEN +Eccentricity parameter for third invariant effects +AN +ET +MCONT +Strain hardening percent of phi max where non-linear effects start +Strain Hardening Amount of non-linear effects +Moisture Content of Soil (Determines amount of air voids) (0.0 - +1.00) +PWD1 +Parameter for pore water effects on bulk modulus +PWKSK +PWD2 +PHIRES +Skeleton bulk modulus- Pore water parameter ñ set to zero to +eliminate effects +Parameter for pore water effects on the effective pressure +(confinement) +The minimum internal friction angle, radians (residual shear +strength) +DINT +Volumetric Strain at Initial damage threshold, EMBED Equation.3 +VDFM +Void formation energy (like fracture energy) +DAMLEV +Level of damage that will cause element deletion (0.0 - 1.00) +EPSMAX +Maximum principle failure strain +*MAT_FHWA_SOIL_NEBRASKA +This is an option to use the default properties determined for soils used at the +University of Nebraska (Lincoln). The default units used for this material are +millimeter, millisecond, and kilograms. If different units are desired, the conversion +factors must be input. +This is Material Type 147. This is an isotropic material with damage and is available for +solid elements. The model has a modified Mohr-Coulomb surface to determine the +pressure dependent peak shear strength. It was developed for applications involving +road base soils. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +FCTIM +FCTMAS +FCTLEN +Type +A8 +F +Default +none +none +I +1 +F +F +F +F +none +1.0 +0.0 +0.0 +I +1 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +FCTIM +Factor to multiply milliseconds by to get desired time units +FCTMAS +Factor to multiply kilograms by to get desired mass units +FCTLEN +Factor to multiply millimeters by to get desired length units +Remarks: +1. As an example, if time units of seconds are desired, then FCTIM = 0.001 +*MAT_148 +This is Material Type 148. This model is for the simulation of thermally equilibrated +ideal gas mixtures. This only works with the multi-material ALE formulation +(ELFORM = 11 in *SECTION_SOLID). This keyword needs to be used together with +*INITIAL_GAS_MIXTURE for the initialization of gas densities and temperatures. +When applied in the context of ALE airbag modeling, the injection of inflator gas is +done with a *SECTION_POINT_SOURCE_MIXTURE command which controls the +injection process. This material model type also has its name start with *MAT_ALE_. +For example, an identical material model to this is *MAT_ALE_GAS_MIXTURE (or +also, *MAT_ALE_02). + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +IADIAB +RUNIV +Type +A8 +Default +none +Remark +I +0 +5 +F +0.0 +1 +Card 2 for Per mass Calculation. Method (A) RUNIV = blank or 0.0. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable CVmass1 CVmass2 CVmass3 CVmass4 CVmass5 CVmass6 CVmass7 CVmass8 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +Card 3 for Per mass Calculation. Method (A) RUNIV = blank or 0.0. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable CPmass1 CPmass 2 CPmass 3 CPmass 4 CPmass 5 CPmass6 CPmass 7 CPmass 8 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +Card 2 for Per Mole Calculation. Method (B) RUNIV is nonzero. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable MOLWT1 MOLWT2 MOLWT3 MOLWT4 MOLWT5 MOLWT6 MOLWT7 MOLWT8 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +Remark +2 +Card 3 for Per Mole Calculation. Method (B) RUNIV is nonzero. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CPmole1 CPmole2 CPmole3 CPmole4 CPmole5 CPmole6 CPmole7 CPmole8 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +Remark +Card 4 for Per Mole Calculation. Method (B) RUNIV is nonzero. + Card 4 +Variable +1 +B1 +Type +F +2 +B2 +F +3 +B3 +F +4 +B4 +F +5 +B5 +F +6 +B6 +F +7 +B7 +F +8 +B8 +F +Default +none +none +none +none +none +none +none +none +Remark +2 +Card 5 for Per Mole Calculation. Method (B) RUNIV is nonzero. + Card 5 +Variable +1 +C1 +Type +F +2 +C2 +F +3 +C3 +F +4 +C4 +F +5 +C5 +F +6 +C6 +F +7 +C7 +F +8 +C8 +F +Default +none +none +none +none +none +none +none +none +Remark +2 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +IADIAB +This flag (default = 0) is used to turn ON/OFF adiabatic +compression logics for an ideal gas (remark 5). +EQ.0: OFF (default) +EQ.1: ON +RUNIV +Universal gas constant in per-mole unit (8.31447 J/(mole*K)). +CVmass1 - +CVmass8 +If RUNIV is BLANK or zero (method A): Heat capacity at +constant volume for up to eight different gases in per-mass unit. +𝐶𝑝(𝑇) +CPmole +kg K +mole K +mole K2 +𝐶 +mole K3 +Figure M148-1. Standard SI units. + VARIABLE +DESCRIPTION +If RUNIV is BLANK or zero (method A): Heat capacity at +constant pressure for up to eight different gases in per-mass unit. +If RUNIV is nonzero (method B): Molecular weight of each ideal +gas in the mixture (mass-unit/mole). +If RUNIV is nonzero (method B): Heat capacity at constant +pressure for up to eight different gases in per-mole unit. These +are nominal heat capacity values typically at STP. These are +denoted by the variable “A” in the equation in remark 2. +If RUNIV is nonzero (method B): First order coefficient for a +temperature dependent heat capacity at constant pressure for up +to eight different gases. These are denoted by the variable “B” in +the equation in remark 2. +If RUNIV is nonzero (method B): Second order coefficient for a +temperature dependent heat capacity at constant pressure for up +to eight different gases. These are denoted by the variable “C” in +the equation in remark 2. +CPmass1 - +CPmass8 +MOLWT1 - +MOLWT8 +CPmole1 - +CPmole8 +B1 - B8 +C1 - C8 +Remarks: +1. There are 2 methods of defining the gas properties for the mixture. If RUNIV is +BLANK or ZERO → Method (A) is used to define constant heat capacities +where per-mass unit values of Cv and Cp are input. Only cards 2 and 3 are +required for this method. Method (B) is used to define constant or temperature +dependent heat capacities where per-mole unit values of Cp are input. Cards 2 - +5 are required for this method. +2. The per-mass-unit, temperature-dependent, constant-pressure heat capacity is +𝐶𝑝(𝑇) = +[CPmole + 𝐵 × 𝑇 + 𝐶 × 𝑇2] +MOLWT +See table M148-1. +3. The initial temperature and the density of the gas species present in a mesh or +part at time zero is specified by the keyword *INITIAL_GAS_MIXTURE. +4. The ideal gas mixture is assumed to be thermal equilibrium, that is, all species +are at the same temperature (T). The gases in the mixture are also assumed to +follow Dalton’s Partial Pressure Law, 𝑃 = ∑ 𝑃𝑖 +. The partial pressure of each +𝑅univ +𝑀𝑊 . The individual gas species temper- +gas is then 𝑃𝑖 = 𝜌𝑖𝑅gas𝑖 +ature equals the mixture temperature. The temperature is computed from the +internal energy where the mixture internal energy per unit volume is used, +𝑇 where 𝑅gas𝑖 +ngas += +ngas +𝑒𝑉 = ∑ 𝜌𝑖𝐶𝑉𝑖 +ngas +𝑇𝑖 = ∑ 𝜌𝑖𝐶𝑉𝑖 +𝑇 +𝑇 = 𝑇𝑖 = +𝑒𝑉 +ngas +∑ 𝜌𝑖𝐶𝑉𝑖 +In general, the advection step conserves momentum and internal energy, but +not kinetic energy. This can result in energy lost in the system and lead to a +pressure drop. In *MAT_GAS_MIXTURE the dissipated kinetic energy is au- +tomatically converted into heat (internal energy). Thus in effect the total energy +is conserved instead of conserving just the internal energy. This numerical +scheme has been shown to improve accuracy in some cases. However, the user +should always be vigilant and check the physics of the problem closely. +5. As an example consider an airbag surrounded by ambient air. As the inflator +gas flows into the bag, the ALE elements cut by the airbag fabric shell elements +will contain some inflator gas inside and some ambient air outside. The multi- +material element treatment is not perfect. Consequently the temperature of the +outside air may be made artificially high after the multi-material element +treatment. To prevent the outside ambient air from getting artificially high T, +set IDIAB = 1 for the ambient air outside. Simple adiabatic compression equa- +tion is then assumed for the outside air. The use of this flag may be needed, but +only when that air is modeled by the *MAT_GAS_MIXTURE card. +Example: +Consider a tank test model where the Lagrangian tank (Part S1) is surrounded by an +ALE air mesh (Part H4 = AMMGID 1). There are 2 ALE parts which are defined but +initially have no corresponding mesh: part 5 (H5 = AMMGID 2) is the resident gas +inside the tank at t = 0, and part 6 (H6 = AMMGID 2) is the inflator gas(es) which is +injected into the tank when t > 0. AMMGID stands for ALE Multi-Material Group ID. +Please see figure and input below. The *MAT_GAS_MIXTURE (MGM) card defines the +gas properties of ALE parts H5 & H6. The MGM card input for both method (A) and +(B) are shown. +The *INITIAL_GAS_MIXTURE card is also shown. It basically specifies that “AM- +MGID 2 may be present in part or mesh H4 at t = 0, and the initial density of this gas is +defined in the rho1 position which corresponds to the 1st material in the mixture (or H5, +the resident gas).” +Example configuration: +Cut-off view +S1 = tank +H4 = AMMG1 = background +outside air (initially defined +ALE mesh) +H5 = AMMG2 = initial +gas +inside the tank (this has no +initial mesh) +H6 = AMMG2 = inflator +gas(es) +injected in (this has no initial +mesh) +Sample input: +$------------------------------------------------------------------------------- +*PART +H5 = initial gas inside the tank +$ PID SECID MID EOSID HGID GRAV ADPOPT TMID + 5 5 5 0 5 0 0 +*SECTION_SOLID + 5 11 0 +$------------------------------------------------------------------------------- +$ Example 1: Constant heat capacities using per-mass unit. +$*MAT_GAS_MIXTURE +$ MID IADIAB R_univ +$ 5 0 0 +$ Cv1_mas Cv2_mas Cv3_mas Cv4_mas Cv5_mas Cv6_mas Cv7_mas Cv8_mas +$718.7828911237.56228 +$ Cp1_mas Cp2_mas Cp3_mas Cp4_mas Cp5_mas Cp6_mas Cp7_mas Cp8_mas +$1007.00058 1606.1117 +$------------------------------------------------------------------------------- +$ Example 2: Variable heat capacities using per-mole unit. +*MAT_GAS_MIXTURE +$ MID IADIAB R_univ + 5 0 8.314470 +$ MW1 MW2 MW3 MW4 MW5 MW6 MW7 MW8 + 0.0288479 0.02256 +$ Cp1_mol Cp2_mol Cp3_mol Cp4_mol Cp5_mol Cp6_mol Cp7_mol Cp8_mol + 29.049852 36.23388 +$ B1 B2 B3 B4 B5 B6 B7 B8 + 7.056E-3 0.132E-1 +$ C1 C2 C3 C4 C5 C6 C7 C8 + -1.225E-6 -0.190E-5 +$------------------------------------------------------------------------------- +$ One card is defined for each AMMG that will occupy some elements of a mesh set +*INITIAL_GAS_MIXTURE +$ SID STYPE MMGID T0 + 4 1 1 298.15 +$ RHO1 RHO2 RHO3 RHO4 RHO5 RHO6 RHO7 RHO8 +1.17913E-9 +*INITIAL_GAS_MIXTURE +$ SID STYPE MMGID T0 + 4 1 2 298.15 +$ RHO1 RHO2 RHO3 RHO4 RHO5 RHO6 RHO7 RHO8 +1.17913E-9 +$------------------------------------------------------------------------------- +*MAT_EMMI +This is Material Type 151. The Evolving Microstructural Model of Inelasticity (EMMI) +is a temperature and rate-dependent state variable model developed to represent the +large deformation of metals under diverse loading conditions [Marin 2005]. This model +is available for 3D solid elements, 2D solid elements and thick shell forms 3 and 5 . + Card 1 +1 +2 +Variable +MID +RHO +Type +A8 + Card 2 +1 +F +2 +Variable +RGAS +BVECT +Type +F + Card 3 +1 +F +2 +3 +E +F +3 +D0 +F +3 +4 +PR +F +4 +QD +F +4 +5 +6 +7 +8 +5 +CV +F +5 +6 +7 +8 +ADRAG +BDRAG +DMTHTA +F +6 +F +7 +F +8 +Variable +DMPHI +DNTHTA +DNPHI +THETA0 +THETAM +BETA0 +BTHETA +DMR +Type +F + Card 4 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +DNUC1 +DNUC2 +DNUC3 +DNUC4 +DM1 +DM2 +DM3 +DM4 +Type +F + Card 5 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +DM5 +Q1ND +Q2ND +Q3ND +Q4ND +CALPHA +CKAPPA +C1 +Type +F +F +F +F +F +F +F +1 +Variable +C2ND +Type +F + Card 7 +1 +Variable +C10 +Type +F + Card 8 +1 +*MAT_151 +2 +C3 +F +2 +A1 +F +2 +3 +C4 +F +3 +A2 +F +3 +4 +C5 +F +4 +A3 +F +4 +5 +C6 +F +5 +A4 +F +5 +6 +7 +8 +C7ND +C8ND +C9ND +F +6 +F +7 +F +8 +A_XX +A_YY +A_ZZ +F +6 +F +7 +F +8 +Variable +A_XY +A_YZ +A_XZ +ALPHXX +ALPHYY +ALPHZZ +ALPHXY +ALPHYZ +Type +F + Card 9 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +ALPHXZ DKAPPA +PHI0 +PHICR +DLBDAG +FACTOR RSWTCH DMGOPT +Type +F + Card 10 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +DELASO DIMPLO +ATOL +RTOL +DINTER +Type +F +F +F +F +*MAT_EMMI + Card 11 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RHO +Material density. +E +PR +Young’s modulus +Poisson’s ratio +RGAS +universal gas constant. +BVECT +Burger’s vector +D0 +QD +CV +pre-exponential diffusivity coefficient +activation energy +specific heat at constant volume +ADRAG +drag intercept +BDRAG +drag coefficient +DMTHTA +shear modulus temperature coefficient +DMPHI +shear modulus damage coefficient +DNTHTA +bulk modulus temperature coefficient +DNPHI +bulk modulus damage coefficient +THETA0 +reference temperature +THETAM +melt temperature +BETA0 +coefficient of thermal expansion at reference temperature +*MAT_151 +DESCRIPTION +BTHETA +thermal expansion temperature coefficient +DMR +damage rate sensitivity parameter +DNUC1 +nucleation coefficient 1 +DNUC2 +nucleation coefficient 2 +DNUC3 +nucleation coefficient 3 +DNUC4 +nucleation coefficient 4 +DM1 +DM2 +DM3 +DM4 +DM5 +Q1ND +Q2ND +Q3ND +Q4ND +coefficient of yield temperature dependence +coefficient of yield temperature dependence +coefficient of yield temperature dependence +coefficient of yield temperature dependence +coefficient of yield temperature dependence +dimensionless activation energy for f +dimensionless activation energy for rd +dimensionless activation energy for Rd +dimensionless activation energy Rs +CALPHA +coefficient for backstress alpha +CKAPPA +coefficient for internal stress kappa +C1 +parameter for flow rule exponent n +C2ND +parameter for transition rate f +C3 +C4 +C5 +C6 +parameter for alpha dynamic recovery rd +parameter for alpha hardening h +parameter for kappa dynamic recovery Rd +parameter for kappa hardening H +C7ND +parameter kappa static recovery Rs +C8ND +C9ND +C10 +A1 +A2 +A3 +A4 +A_XX +A_YY +A_ZZ +A_XY +A_YZ +A_XZ +*MAT_EMMI +DESCRIPTION +parameter for yield +parameter for temperature dependence of flow rule exponent n +parameter for static recovery (set = 1) +plastic anisotropy parameter +plastic anisotropy parameter +plastic anisotropy parameter +plastic anisotropy parameter +initial structure tensor component +initial structure tensor component +initial structure tensor component +initial structure tensor component +initial structure tensor component +initial structure tensor component +ALPHXX +initial backstress component +ALPHYY +initial backstress component +ALPHZZ +initial backstress component +ALPHXY +initial backstress component +ALPHYZ +initial backstress component +ALPHXZ +initial backstress component +DKAPPA +initial isotropic internal stress +PHI0 +initial isotropic porosity +PHICR +critical cutoff porosity +DLBDAG +slip system geometry parameter +FACTOR +fraction of plastic work converted to heat, adiabatic +*MAT_151 +DESCRIPTION +RSWTCH +rate sensitivity switch +DMGOPT +Damage model option parameter +EQ.1.0: pressure independent Cocks/Ashby 1980 +EQ.2.0: pressure dependent Cocks/Ashby 1980 +EQ.3.0: pressure dependent Cocks 1989 +DELASO +Temperature option +EQ.0.0: driven externally +EQ.1.0: adiabatic +DIMPLO +Implementation option flag +EQ.1.0: combined viscous drag and +thermally activated +dislocation motion +EQ.2.0: separate viscous drag and +thermally activated +dislocation motion +ATOL +RTOL +absolute error tolerance for local Newton iteration +relative error tolerance for local Newton iteration +DNITER +maximum number of iterations for local Newton iteration +Remarks: +∇ += ℎ 𝐝𝑝 − 𝑟𝑑 𝜀̅ +̇𝑝𝛼̅ 𝛂 +̇𝑝 − 𝑅𝑠𝜅sinh(𝑄𝑠𝜅) +𝜅̇ = (𝐻 − 𝑅𝑑𝜅)𝜀̅ +𝐝p = √ + 𝜀̅ +̇𝑝𝐧, 𝜀̅ +̇𝑝 = 𝑓sinh𝑛 [⟨ +𝜎̅̅̅̅̅ +𝜅 + 𝑌 +− 1⟩] +̇𝑝 − equation +𝜀̅ +𝑓 = 𝑐2exp ( +𝑄1 +) +𝑛 = +𝑐9 +− 𝑐1 +𝑌 = 𝑐8𝑌̂(𝜃) +𝛂 − equation +𝜅 − equation +𝑟𝑑 = 𝑐3exp ( +−𝑄2 +) +𝑅𝑑 = 𝑐5exp ( +−𝑄3 +) +ℎ = 𝑐4𝜇̂(𝜃) +𝐻 = 𝑐6𝜇̂(𝜃) +𝑅𝑠 = 𝑐7exp ( +−𝑄4 +) +𝑄𝑠 = 𝑐10exp ( +−𝑄5 +) +Table M151-1. Plasticity Material Functions of EMMI Model. +Void growth: +𝜑̇ = +√2 +(1 − 𝜑)𝐺̂(𝜎̅̅̅̅̅𝑒𝑞, 𝑝̅, 𝜑)𝜀̅ +̇𝑝 +𝐺̂(𝜎̅̅̅̅̅𝑒𝑞, 𝑝̅𝜏, 𝜑) = +√3 +[ +(1 − 𝜑)𝑚 + 1 +− 1] sinh [ +2(2𝑚 − 1) +2𝑚 + 1 +⟨𝑝̅⟩ +𝜎̅̅̅̅̅𝑒𝑞 +] +*MAT_153 +This is Material Type 153. This model has two back stress terms for kinematic +hardening combined with isotropic hardening and a damage model for modeling low +cycle fatigue and failure. Huang [2006] programmed this model and provided it as a +user subroutine with the documentation that follows. It is available for beam, shell and +solid elements. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +E +F +3 +4 +PR +F +4 +5 +6 +7 +8 +SIGY +HARDI +BETA +LCSS +F +5 +F +6 +F +7 +I +8 +Variable +HARDK1 GAMMA1 HARDK2 GAMMA2 +SRC +SRP +HARDK3 GAMMA3 +Type +F + Card 3 +1 +F +2 +F +3 +F +4 +Variable +IDAM +IDS +IDEP +EPSD +Type +I +I +I +F +F +8 +F +5 +S +F +F +6 +T +F +F +7 +DC +F +Optional Card 4 + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +HARDK4 GAMMA4 +Type +F +MID +RO +E +PR +*MAT_DAMAGE_3 +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density, 𝜌 +Young’s modulus, E +Poisson’s ratio, 𝑣 +SIGY +Initial yield stress, 𝜎𝑦0 (ignored if LCSS.GT.0) +HARDI +Isotropic hardening modulus, H (ignored if LCSS.GT.0) +BETA +LCSS +Isotropic hardening parameter, 𝛽. Set 𝛽 = 0 for linear isotropic +hardening. (Ignored if LCSS.GT.0 or if HARDI.EQ.0.) +Load curve ID defining effective stress vs. effective plastic strain +for isotropic hardening. The first abscissa value must be +zero corresponding to the initial yield stress. The first ordinate +value is the initial yield stress. +HARDK1 +Kinematic hardening modulus 𝐶1 +GAMMA1 +Kinematic hardening parameter 𝛾1. Set 𝛾1 = 0 for linear +kinematic hardening. Ignored if (HARDK1.EQ.0) is defined. +HARDK2 +Kinematic hardening modulus 𝐶2 +GAMMA2 +SRC +SRP +Kinematic hardening parameter 𝛾2 +kinematic hardening. Ignored if (HARDK2.EQ.0) is defined. +Set 𝛾2 = 0 for linear +. +Strain rate parameter, C, for Cowper Symonds strain rate model, +see below. If zero, rate effects are not considered. +Strain rate parameter, P, for Cowper Symonds strain rate model, +see below. If zero, rate effects are not considered. +HARDK3 +Kinematic hardening modulus 𝐶3 +GAMMA3 +Kinematic hardening parameter 𝛾3 +kinematic hardening. Ignored if (HARDK3.EQ.0) is defined. +Set 𝛾3 = 0 for linear +. +VARIABLE +DESCRIPTION +IDAM +Isotropic damage flag +EQ.0: damage is inactivated. IDS, IDEP, EPSD, S, T, DC are +ignored. +EQ.1: damage is activated +IDS +Output stress flag +EQ.0: undamaged stress is 𝜎̃ output +EQ.1: damaged stress is 𝜎̃ (1 − 𝐷) output +IDEP +Damaged plastic strain +EQ.0: plastic strain is accumulated 𝑟 = ∫ 𝜀̅ +̇𝑝𝑙 +EQ.1: damaged plastic strain is accumulated 𝑟 = ∫(1 − 𝐷)𝜀̅ +̇𝑝𝑙 +EPSD +Damage threshold 𝑟𝑑. Damage accumulation begins when 𝑟 > 𝑟𝑑 +S +T +DC +Damage material constant S. Default = 𝜎𝑦0 200 +⁄ +Damage material constant t. Default = 1 +Critical damage value 𝐷𝑐. When damage value reaches critical, +the element is deleted from calculation. Default = 0.5 +HARDK4 +Kinematic hardening modulus 𝐶4 +Kinematic hardening parameter 𝛾4 +kinematic hardening. Ignored if (HARDK4.EQ.0) is defined. +Set 𝛾4 = 0 for linear +. +GAMMA4 +Remarks: +This model is based on the work of Lemaitre [1992], and Dufailly and Lemaitre [1995]. +It is a pressure-independent plasticity model with the yield surface defined by the +function +where 𝜎𝑣 is uniaxial yield stress +𝐹 = 𝜎̅̅̅̅̅ − 𝜎𝑦 = 0 +𝜎𝑦 = 𝜎𝑦0 + +[1 − exp(−𝛽𝑟)] +By setting 𝛽 = 0, a linear isotropic hardening is obtained +𝜎𝑦 = 𝜎𝑦0 + 𝐻𝑟 +where 𝜎𝑣0 s the initial yield stress. And 𝜎̅̅̅̅̅ is the equivalent von Mises stress, with +respect to the deviatoric effective stress +where s is deviatoric stress and α is the back stress, which is decomposed into several +components +se = 𝑑𝑒𝑣[σ̃] − α = s − α +and σ̃ is effective stress (undamaged stress), based on Continuum Damage Mechanics +model [Lemaitre 1992] +α = ∑ αj +σ̃ = +1 − 𝐷 +where D is the isotropic damage scalar, which is bounded by 0 and 1 +0 ≤ 𝐷 ≤ 1 +D = 0 represents a damage-free material RVE (representative volume element), while +D = 1 represents a fully broken material RVE in two parts. In fact, fracture occurs when +𝐷 = 𝐷𝑐 < 1, modeled as element removal. The evolution of the isotropic damage value +related to ductile damage and fracture (the case where the plastic strain or dissipation is +much larger than the elastic one, [Lemaitre 1992]) is defined as +𝐷̇ = +⎧ +{ +⎨ +{ +⎩ +) +( +̇pl +𝜀̅ +𝑟 > 𝑟𝑑& +𝜎𝑚 +𝜎eq +otherwise +> − +where +𝜎𝑚 +𝜎𝑒𝑞 + is the stress triaxiality, 𝑟𝑑 is damage threshold, S is a material constant, and Y +is strain energy density release rate. +𝑌 = +εel: 𝐃el: εel +Where 𝐃el represents the fourth-order elasticity tensor, εel is elastic strain. And t is a +material constant, introduced by Dufailly and Lemaitre [1995], to provide additional +degree of freedom for modeling low-cycle fatigue (𝑡 = 1 in Lemaitre [1992]). Dufailly +and Lemaitre [1995] also proposed a simplified method to fit experimental results and +get S and t. +The equivalent Mises stress is defined as +𝜎̅̅̅̅̅(s𝑒) = √ +s𝑒: s𝑒 = √ +∥s𝑒∥ +The model assumes associated plastic flow +ε̇pl = +∂𝐹 +∂σ +𝑑𝜆 = +s𝑒 +𝜎̅̅̅̅̅ +𝑑𝜆 +Where 𝑑𝜆 is the plastic consistency parameter. The evolution of the kinematic +component of the model is defined as [Armstrong and Frederick 1966]: +α̇𝑗 = +⎧ +{{ +⎨ +{{ +⎩ +𝐶𝑗ε̇pl − 𝛾𝑗α𝑗𝜀̅ +̇pl IDEP = 0 +α̇𝑗 = (1 − 𝐷) ( +𝐶𝑗ε̇pl − 𝛾𝑗α𝑗𝜀̅ +̇pl) IDEP = 1 +The damaged plastic strain is accumulated as +̇pl IDEP = 0 +⎧𝑟 = ∫ 𝜀̅ +{ +{⎨ +𝑟 = ∫(1 − 𝐷)𝜀̅ +⎩ +̇pl IDEP = 1 +where 𝜀̅ +̇pl is the equivalent plastic strain rate +where ε̇pl represents the rate of plastic flow. +̇pl = √ +𝜀̅ +ε̇pl: ε̇pl +Strain rate is accounted for using the Cowper and Symonds model which scales the +yield stress with the factor +where 𝜀̇ is the strain rate. +1 + ( +𝑝⁄ +) +𝜀̇ +Table 153.1 shows the difference between MAT 153 and MAT 104/105. MAT 153 is less +computationally expensive than MAT 104/105. Kinematic hardening, which already +exists in MAT 103, is included in MAT 153, but not in MAT 104/105. +MAT 153 +MAT 104 +MAT 105 +Computational cost +1.0 +3.0 +3.0 +Isotropic hardening One component +Two components One component +Kinematic hardening +Four components +N/A +N/A +Output stress +Damagedplastic strain +Accumulation when +Isotropic plasticity +Anisotropic plasticity +Isotropic damage +Anisotropic damage +IDS = 0  𝜎̃ +IDS = 1  𝜎̃ (1 − 𝐷) +IDEP = 0  +𝑟 = ∫ 𝜀̅ +̇pl +IDEP = 1  +𝑟 = ∫(1 − 𝐷)𝜀̅ +̇pl +𝜎𝑚 +𝜎𝑒𝑞 +> − +Yes +No +Yes +No +𝜎̃ (1 − 𝐷) +𝜎̃ (1 − 𝐷) +𝑟 = ∫(1 − 𝐷)𝜀̅ +̇pl +𝑟 = ∫(1 − 𝐷)𝜀̅ +̇pl +𝜎1 > 0 +𝜎1 > 0 +Yes +Yes +Yes +Yes +Yes +No +Yes +No +Table M153-1. Differences between MAT 153 and MAT 104/105 +*MAT_DESHPANDE_FLECK_FOAM +This is material type 154 for solid elements. This material is for modeling aluminum +foam used as a filler material in aluminum extrusions to enhance the energy absorbing +capability of the extrusion. Such energy absorbers are used in vehicles to dissipate +energy during impact. This model was developed by Reyes, Hopperstad, Berstad, and +Langseth [2002] and is based on the foam model by Deshpande and Fleck [2000]. + Card 1 +1 +2 +Variable +MID +RHO +Type +A8 +F +3 +E +F +4 +PR +F +5 +6 +7 +8 +ALPHA +GAMMA +F +F +Default +none +none +none +none +none +none + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EPSD +ALPHA2 +BETA +SIGP +DERFI +CFAIL +PFAIL +NUM +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RHO +Mass density. +E +PR +Young’s modulus. +Poisson’s ratio. +ALPHA +Controls shape of yield surface. +GAMMA +See remarks. +EPSD +Densification strain. +*MAT_DESHPANDE_FLECK_FOAM +DESCRIPTION +ALPHA2 +See remarks. +BETA +SIGP +See remarks. +See remarks. +DERFI +Type of derivation used in material subroutine +EQ.0: Numerical derivation +EQ.1: Analytical derivation +Failure volumetric strain. +Failure principal stress. Must be sustained NUM (>0) timesteps +to fail element. +CFAIL +PFAIL +NUM +Number of timesteps at or above PFAIL to trigger element failure. +Remarks: +The yield stress function Φ is defined by: +The equivalent stress 𝜎̂ is given by: +Φ = 𝜎̂ − 𝜎𝑦 +𝜎̂ 2 = +𝜎𝑉𝑀 +2 + 𝛼2𝜎𝑚 +1 + (𝛼 +) +where, 𝜎𝑉𝑀, is the von Mises effective stress: +𝜎𝑉𝑀 = √ +σdev: σdev +In this equation 𝜎𝑚 and 𝜎 𝑑𝑒𝑣 are the mean and deviatoric stress: +The yield stress 𝜎𝑦 can be expressed as: +σdev = σ − 𝜎𝑚I +𝜎𝑦 = 𝜎𝑝 + 𝛾 +𝜀̂ +𝜀𝐷 ++ 𝛼2ln +⎡ +⎢ +1 − ( 𝜀̂ +⎣ +𝜀𝐷 +⎤ +⎥ +⎦ +) +Here, 𝜎𝑝, 𝛼2, 𝛾 and 𝛽 are material parameters. The densification strain 𝜀𝐷 is defined +as: +𝜀𝐷 = −ln ( +𝜌𝑓 +𝜌𝑓0 +) +where 𝜌𝑓 is the foam density and 𝜌𝑓0 is the density of the virgin material. +*MAT_PLASTICITY_COMPRESSION_TENSION_EOS +This is Material Type 155. An isotropic elastic-plastic material where unique yield +stress versus plastic strain curves can be defined for compression and tension. Also, +failure can occur based on a plastic strain or a minimum time step size. Rate effects on +the yield stress are modeled either by using the Cowper-Symonds strain rate model or +by using two load curves that scale the yield stress values in compression and tension, +respectively. Material rate effects, which are independent of the plasticity model, are +based on a 6-term Prony series Maxwell mode that generates an additional stress tensor. +The viscous stress tensor is superimposed on the stress tensor generated by the +plasticity. Pressure is defined by an equation of state, which is required to utilize this +model. This model is applicable to solid elements and SPH. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +Default +none +none +none +none + Card 2 +1 +2 +3 +4 +5 +C +F +0 +5 +6 +P +F +0 +6 +7 +8 +FAIL +TDEL +F +10.E+20 +7 +F +0 +8 +Variable +LCIDC +LCIDT +LCSRC +LCSRT +SRFLAG +Type +Default + Card 3 +Variable +Type +Default +I +0 +1 +PC +F +0 +I +0 +2 +PT +F +0 +I +0 +3 +I +0 +4 +F +0 +5 +6 +7 +8 +PCUTC +PCUTT +PCUTF +SCALEP +SCALEE +F +0 +F +0 +F +0 +F +0 +F +2 +3 +4 +5 +6 +7 +8 + Card 4 +Variable +Type +1 +K +F +Viscoelastic Constant Cards. Card Format for viscoelastic constants. Up to 6 cards +may be input. A keyword card (with a “*” in column 1) terminates this input if less +than 6 cards are used. + Optional +Variable +Type +1 +GI +F + VARIABLE +MID +RO +E +PR +C +P +2 +3 +4 +5 +6 +7 +8 +BETAI +F +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +Strain rate parameter, C, see formula below. +Strain rate parameter, P, see formula below. +FAIL +Failure flag. +LT.0.0: User defined failure subroutine, matusr_24 in dyn21.F, +is called to determine failure +EQ.0.0: Failure is not considered. This option is recommended +if failure is not of interest since many calculations will +be saved. +GT.0.0: Plastic strain to failure. When the plastic strain reaches +this value, the element is deleted from the calculation. +TDEL +Minimum time step size for automatic element deletion. +LCIDC +LCIDT +LCSRC +LCSRT +*MAT_PLASTICITY_COMPRESSION_TENSION_EOS +DESCRIPTION +Load curve ID defining yield stress versus effective plastic strain +in compression. +Load curve ID defining yield stress versus effective plastic strain +in tension. +Optional load curve ID defining strain rate scaling effect on yield +stress when the material is in compression. +Optional load curve ID defining strain rate scaling effect on yield +stress when the material is in tension. +SRFLAG +Formulation for rate effects: +EQ.0.0: Total strain rate, +EQ.1.0: Deviatoric strain rate. +PC +PT +PCUTC +PCUTT +Compressive mean stress (pressure) at which the yield stress +follows load curve ID, LCIDC. If the pressure falls between PC +and PT a weighted average of the two load curves is used. +Tensile mean stress at which the yield stress follows load curve +ID, LCIDT. +Pressure cut-off in compression. When the pressure cut-off is +reached the deviatoric stress tensor is set to zero. + The +compressive pressure is not, however, limited to PCUTC. Like +the yield stress, PCUTC is scaled to account for rate effects. +Pressure cut-off in tension. When the pressure cut-off is reached +the deviatoric stress tensor and tensile pressure is set to zero. +Like the yield stress, PCUTT is scaled to account for rate effects. +PCUTF +Pressure cut-off flag. +EQ.0.0: Inactive, +EQ.1.0: Active. +SCALEP +Scale factor applied to the yield stress after the pressure cut-off is +reached in either compression or tension. + If SCALEP = 0 +(default), the deviatoric stress is set to zero after the cut-off is +reached. +VARIABLE +SCALEE +K +GI +DESCRIPTION +Scale factor applied to the yield stress after the strain exceeds the +failure strain set by FAIL. If SCALEE = 0 (default), the deviatoric +strain is set to zero if the failure strain is exceeded. IF both +SCALEP > 0 and SCALEE > 0 and both failure conditions are met, +then the minimum scale factor is used. +Optional bulk modulus for the viscoelastic material. If nonzero a +Kelvin type behavior will be obtained. Generally, K is set to zero. +Optional shear relaxation modulus for the ith term +BETAI +Optional shear decay constant for the ith term +Remarks: +The stress strain behavior follows a different curve in compression than it does in +tension. Tension is determined by the sign of the mean stress where a positive mean +stress (i.e., a negative pressure) is indicative of tension. Two curves must be defined +giving the yield stress versus effective plastic strain for both the tension and +compression regimes. +Mean stress is an invariant which can be expressed as (σx + σy + σz)/3. PC and PT +define a range of mean stress values within which interpolation is done between the +tensile yield surface and compressive yield surface. PC and PT are not true material +properties but are just a numerical convenience so that the transition from one yield +surface to the other is not abrupt as the sign of the mean stress changes. Both PC and +PT are input as positive values as it is implied that PC is a compressive mean stress +value and PT is tensile mean stress value. +Strain rate may be accounted for using the Cowper and Symonds model which scales +the yield stress with the factor: +where 𝜀̇ is the strain rate, +1 + ( +𝑝⁄ +) +𝜀̇ +𝜀̇ = √𝜀̇𝑖𝑗𝜀̇𝑖𝑗. +*MAT_PLASTICITY_COMPRESSION_TENSION_EOS +History Variable +Description +4 +5 +6 +7 +Tensile pressure cutoff (set to zero if +tensile or compressive failure occurs) +The cutoff flag, initially equals 1, set to +0 if tensile or compressive failure +occurs +The failure mode flag +EQ.0: if no failure +EQ.1: if compressive failure +EQ.2: if tensile failure +EQ.3: if failure by plastic strain +The current flow stress +*MAT_156 +This is material type 156 for truss elements. This material is a Hill-type muscle model +with activation and a parallel damper. Also, see *MAT_SPRING_MUSCLE where a +description of the theory is available. + Card 1 +1 +Variable +MID +2 +RO +3 +4 +5 +6 +7 +8 +SNO +SRM +PIS +SSM +CER +DMP +Type +A8 +F +F +F +F +F +F +F +Default + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ALM +SFR +SVS +SVR +SSP +Type +F +F +F +F +F +Default +0.0 +1.0 +1.0 +1.0 +0.0 + VARIABLE +DESCRIPTION +MID +RO +SNO +SRM +PIS +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Material density in the initial undeformed configuration. +Initial stretch ratio, +𝑙0 +𝑙orig +, i.e., the length as defined by the nodal +points at t = 0 divided by the original initial length. The density +for the nodal mass calculation is RO/SNO, or +𝑙orig +𝑙0 +𝜌. +Maximum strain rate. +Peak isometric stress corresponding to the dimensionless value of +unity in the dimensionless stress versus strain function, see SSP +below. +SSM +CER +DMP +ALM +*MAT_MUSCLE +DESCRIPTION +Strain when the dimensionless stress versus strain function, SSP +below, reaches its maximum stress value. +Constant, governing the exponential rise of SSP. Required if +SSP = 0. +Damping constant (stress × time units). +Activation level vs. time. +LT.0: absolute value gives load curve ID +GE.0: constant value of ALM is used +SFR +Scale factor for strain rate maximum vs. activation level, 𝑎(𝑡). +LT.0: absolute value gives load curve ID +GE.0: constant value of 1.0 is used +SVS +SVR +Active dimensionless tensile stress vs. the stretch ratio, +𝑙orig +. +LT.0: absolute value gives load curve ID +GE.0: constant value of 1.0 is used +Active dimensionless tensile stress vs. the normalized strain rate, +̇. +𝜀̅ +LT.0: absolute value gives load curve ID +GE.0: constant value of 1.0 is used +SSP +Isometric dimensionless stress vs. the stretch ratio, +𝑙orig + for the +parallel elastic element. +LT.0: absolute value gives load curve ID or table ID +EQ.0: exponential function is used +GT.0: constant value of 0.0 is used +Remarks: +The material behavior of the muscle model is adapted from *MAT_S15, the spring +muscle model and treated here as a standard material. The initial length of muscle is +calculated automatically. The force, relative length and shortening velocity are replaced +by stress, strain and strain rate. A new parallel damping element is added. +The strain 𝜀 and normalized strain rate 𝜀̅ +̇ are defined respectively as +and, +𝜀 = +𝑙orig +− 1 += SNO × +𝑙0 +− 1 +𝜀̅ +̇ = +𝑙orig +𝜀̇ +𝜀̇max += SNO × +𝑙0 +× +𝜀̇ +SFR × SRM +where 𝜀̇ = ∆𝜀/∆𝑡 (current strain increment divided by current time step), l = current +muscle length, and 𝑙orig = original muscle length. +From the relation above, it is known: +𝑙orig = +𝑙0 +1 + 𝜀0 +where 𝜀0 = SNO − 1 and 𝑙0 = muscle length at time 0. +Stress of Contractile Element is: +𝜎1 = 𝜎max𝑎(𝑡)𝑓 ( +𝑙orig +) 𝑔(𝜀̅ +̇) +where 𝜎max = PIS, 𝑎(𝑡) = ALM, 𝑓 (𝑙/𝑙orig) = SVS, and 𝑔(𝜀̅ +̇) = SVR. +Stress of Passive Element is: +𝜎2 = +⎧ +{{{ +⎨ +{{{ +⎩ +𝜎maxℎ ( +̇, +𝜎maxℎ (𝜀̅ +) +𝑙orig +𝑙orig +for curve +) for table +where ℎ = SSP. For SSP < 0, the absolute value gives a load curve ID or table ID. The +load curve defines isometric dimensionless stress ℎ versus stretch ratio 𝑙/𝑙orig. The table +̇ a load curve giving the isometric dimension- +defines for each normalized strain rate 𝜀̅ +less stress ℎ versus stretch ratio 𝑙/𝑙orig for that rate. +*MAT_MUSCLE +⎜⎜⎜⎜⎛ +⎝ +⁄ +𝑙orig += +⎟⎟⎟⎟⎞ +⎠ +exp(CER) − 1 +⎧0 +{ +{ +{ +{ +{ +{ +⎨ +{ +{ +{ +{ +{ +{ +⎩ +SSM +⁄ < 1 +𝑙orig +[ exp ( +CER +SSM +𝜀) − 1] +⁄ ≥ 1 CER ≠ 0 +𝑙orig +⁄ ≥ 1 CER = 0 +𝑙orig +Stress of Damping Element is: +Total Stress is: +σ3 = DMP × +𝑙orig + ε̇ +𝜎 = 𝜎1 + 𝜎2 + 𝜎3 +*MAT_ANISOTROPIC_ELASTIC_PLASTIC +This is Material Type 157. This material model is a combination of the anisotropic +elastic material model (MAT_002) and the anisotropic plastic material model (MAT_- +103_P). Also, brittle orthotropic failure based on a phenomenological Tsai-Wu criterion +can be defined. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +4 +5 +6 +7 +8 +SIGY +LCSS +QR1 +CR1 +QR2 +CR2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +C11 +C12 +C13 +C14 +C15 +C16 +C22 +C23 +Type +F + Card 3 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +C24 +C25 +C26 +C33 +C34 +C35 +C36 +C44 +Type +F + Card 4 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +C45 +C46 +C55 +C56 +C66 +R00 or F R45 or G R90 or H +Type +F + Card 5 +1 +F +2 +F +3 +F +4 +F +5 +Variable +S11 or L S22 or M S33 or N +S12 +AOPT +Type +F +F +F +F +F +F +6 +VP +F +F +7 +F +8 +MACF +Variable +1 +XP +Type +F + Card 7 +Variable +1 +V1 +Type +F +*MAT_ANISOTROPIC_ELASTIC_PLASTIC +2 +YP +F +2 +V2 +F +3 +ZP +F +3 +V3 +F +4 +A1 +F +4 +D1 +F +5 +A2 +F +5 +D2 +F +6 +A3 +F +6 +D3 +F +7 +8 +EXTRA +F +8 +7 +BETA +IHIS +F +F +Two additional cards for EXTRA = 1 or 2. + Card 8 +Variable +1 +XT +Type +F + Card 9 +Variable +1 +ZT +Type +F +2 +XC +F +2 +ZC +F +3 +YT +F +3 +4 +YC +F +4 +5 +6 +7 +8 +SXY +FF12 +NCFAIL +F +5 +F +6 +7 +F +8 +SYZ +SZX +FF23 +FF31 +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +SIGY +LCSS +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Initial yield stress +Load curve ID or Table ID. +Load Curve. When LCSS is a Load curve ID, it is taken as +defining effective stress versus effective plastic strain. If defined +VARIABLE +DESCRIPTION +QR1, CR1, QR2, and CR2 are ignored. +Tabular Data. The table ID defines for each strain rate value a +load curve ID giving the stress versus effective plastic strain for +that rate, See Figure M24-1. When the strain rate falls below the +minimum value, the stress versus effective plastic strain curve for +the lowest value of strain rate is used. Likewise, when the strain +rate exceeds the maximum value the stress versus effective plastic +strain curve for the highest value of strain rate is used. +Logarithmically Defined Tables. If the first stress-strain curve in +the table corresponds to a negative strain rate, LS-DYNA assumes +that the natural logarithm of the strain rate value is used for all +stress-strain curves. Since the tables are internally discretized to +equally space the points, natural logarithms are necessary, for +example, if the curves correspond to rates from 10−4 to 104. +Computing natural logarithms can substantially increase the +computational time on certain computer architectures. +Isotropic hardening parameter +Isotropic hardening parameter +Isotropic hardening parameter +Isotropic hardening parameter +The i, j term in the 6 × 6 anisotropic constitutive matrix. Note that +1 corresponds to the a material direction, 2 to the b material +direction, and 3 to the c material direction. +𝑅00 for shell +(Default = 1.0) +𝑅45 for shell +(Default = 1.0) +𝑅90 for shell +(Default = 1.0) +𝐹 for brick +(Default = 1 2⁄ ) +𝐺 for brick +(Default = 1 2⁄ ) +𝐻 for brick +(Default = 1 2⁄ ) +𝐿 for brick +(Default = 3 2⁄ ) +𝑀 for brick +(Default = 3 2⁄ ) +QR1 +CR1 +QR2 +CR2 +Cij +R00 +R45 +R90 +F +G +H +L +N +S11 +S22 +S33 +S12 +*MAT_ANISOTROPIC_ELASTIC_PLASTIC +DESCRIPTION +𝑁 for brick +(Default = 3 2⁄ ) +Yield stress in local-x direction (shells only). This input is ignored +when +R00, R45, R90 > 0. +Yield stress in local-y direction (shells only). This input is ignored +when +R00, R45, R90 > 0. +Yield stress in local-z direction (shells only). This input is ignored +when +R00, R45, R90 > 0. +Yield stress in local-xy direction (shells only). This input is +ignored when +R00, R45, R90 > 0. +AOPT +Material axes option . Available in R3 version of 971 +and later. +VARIABLE +DESCRIPTION +VP +Formulation for rate effects: +EQ.0.0: scale yield stress (default), +EQ.1.0: viscoplastic formulation. +MACF +Material axes change flag for brick elements: +EQ.1: No change, default, +EQ.2: switch material axes 𝑎 and 𝑏, +EQ.3: switch material axes 𝑎 and 𝑐, +EQ.4: switch material axes 𝑏 and 𝑐. +XP, YP, ZP +coordinates of point 𝐩 for AOPT = 1 and 4. +A1, A2, A3 +components of vector 𝐚 for AOPT = 2. +D1, D2, D3 +components of vector 𝐝 for AOPT = 2. +V1, V2, V3 +components of vector 𝐯 for AOPT = 3 and 4. +BETA +Material angle in degrees for AOPT = 0 (shells only) and +AOPT = 3. BETA may be overridden on the element card, see +*ELEMENT_SHELL_BETA and *ELEMENT_SOLID_ORTHO. +IHIS +Flag for material properties initialization. +EQ.0: material properties defined in Cards 1-5 are used +GE.1: Use +*INITIAL_STRESS_SOLID/SHELL +initialize +material properties on an element-by-element basis for +solid or shell elements, respectively . +to +EXTRA +Flag to input further data : +EQ.1.0: Tsai-Wu failure criterion parameters (cards 8 and 9) +EQ.2.0: Tsai-Hill failure criterion parameters (cards 8 and 9) +XT +Longitudinal tensile strength, a-axis. +GT.0.0: constant value +LT.0.0: Load curve ID = (-XT) which defines the longitudinal +tensile strength vs. strain rate. If the first strain rate +value in the curve is negative, it is assumed that all +strain rate values are given as natural logarithm of the +strain rate. +*MAT_ANISOTROPIC_ELASTIC_PLASTIC +DESCRIPTION +XC +Longitudinal compressive strength, a-axis (positive value). +GT.0.0: constant value +LT.0.0: Load curve ID = (-XC) which defines the longitudinal +compressive strength vs. strain rate. If the first strain +rate value in the curve is negative, it is assumed that all +strain rate values are given as natural logarithm of the +strain rate. +YT +Transverse tensile strength, b-axis. +GT.0.0: constant value +LT.0.0: Load curve ID = (-YT) which defines the transverse +tensile strength vs. strain rate. If the first strain rate +value in the curve is negative, it is assumed that all +strain rate values are given as natural logarithm of the +strain rate. +YC +Transverse compressive strength, b-axis (positive value). +GT.0.0: constant value +LT.0.0: Load curve ID = (-YC) which defines the transverse +compressive strength vs. strain rate. If the first strain +rate value in the curve is negative, it is assumed that all +strain rate values are given as natural logarithm of the +strain rate. +SXY +Shear strength, ab-plane. +GT.0.0: constant value +LT.0.0: Load curve ID = (-SXY) which defines the shear +strength vs. strain rate. If the first strain rate value in +the curve is negative, it is assumed that all strain rate +values are given as natural logarithm of the strain rate. +FF12 +NCFAIL +Scale factor between -1 and +1 for interaction term F12, see +Remarks. +Number of timesteps to reduce stresses until element deletion. +The default is NCFAIL = 10. +VARIABLE +DESCRIPTION +ZT +Transverse tensile strength, c-axis (solid elements only). +GT.0.0: constant value +LT.0.0: Load curve ID = (-ZT) which defines the transverse +tensile strength vs. strain rate. If the first strain rate +value in the curve is negative, it is assumed that all +strain rate values are given as natural logarithm of the +strain rate. +ZC +Transverse compressive strength, c-axis (positive value) +(solid elements only). +GT.0.0: constant value +LT.0.0: Load curve ID = (-ZC) which defines the transverse +compressive strength vs. strain rate. If the first strain +rate value in the curve is negative, it is assumed that all +strain rate values are given as natural logarithm of the +strain rate. +SYZ +Shear strength, bc-plane (solid elements only). +GT.0.0: constant value +LT.0.0: Load curve ID = (-SYZ) which defines the shear +strength vs. strain rate. If the first strain rate value in +the curve is negative, it is assumed that all strain rate +values are given as natural logarithm of the strain rate. +SZX +Shear strength, ca-plane (solid elements only). +GT.0.0: constant value +LT.0.0: Load curve ID = (-SZX) which defines the shear +strength vs. strain rate. If the first strain rate value in +the curve is negative, it is assumed that all strain rate +values are given as natural logarithm of the strain rate. +FF23 +FF31 +Scale factor between -1 and +1 for interaction term F23, see +Remarks +(solid elements only). +Scale factor between -1 and +1 for interaction term F31, see +Remarks +(solid elements only). +Description of IHIS (Solid Elements): +Several of this material’s parameters may be overwritten on an element-by-element +basis through history variables using the *INITIAL_STRESS_SOLID keyword. Bitwise +(binary) expansion of IHIS determines which material properties are to be read: +IHIS = 𝑎3 × 8 + 𝑎2 × 4 + 𝑎1 × 2 + 𝑎0, +where each 𝑎𝑖 is a binary flag set to either 1 or 0. The 𝑎𝑖 are interpreted according to the +following table. +Flag +Description +Variables +𝑎0 Material directions +𝑞11, 𝑞12, 𝑞13, 𝑞31, 𝑞32, 𝑞33 +𝑎1 +𝑎2 +𝑎3 +Anisotropic stiffness +Cij +Anisotropic constants +F, G, H, L, M, N +Stress-strain Curve +LCSS +# +6 +21 +6 +1 +The NHISV field on *INITIAL_STRESS_SOLID must be set equal to the sum of the +number of variables to be read in, which depends on IHIS (and the 𝑎𝑖): +NHISV = 6𝑎0 + 21𝑎1 + 6𝑎2 + 𝑎3. +Then, in the following order, *INITIAL_STRESS_SOLID processes the history variables, +HISVi, as: +1. +2. +3. +4. +6 material direction parameters when 𝑎0 = 1 +21 anisotropic stiffness parameters when 𝑎1 = 1 +6 anisotropic constants when 𝑎2 = 1 +1 parameters when 𝑎3 = 1 +The 𝑞𝑖𝑗 terms are the first and third rows of a rotation matrix for the rotation from a co- +rotational element’s system and the 𝑎-𝑏-𝑐 material directions. The 𝑐𝑖𝑗 terms are the +upper triangular terms of the symmetric stiffness matrix, 𝑐11, 𝑐12, 𝑐13, 𝑐14, 𝑐15, 𝑐16, 𝑐22, +𝑐23, 𝑐24, 𝑐25, 𝑐26, 𝑐33, 𝑐34, 𝑐35, 𝑐36, 𝑐44, 𝑐45, 𝑐46, 𝑐55, 𝑐56, and 𝑐66. +Description of IHIS (Shell Elements): +Several of this material’s parameters may be overwritten on an element-by-element +basis through history variables using the *INITIAL_STRESS_SHELL keyword. Bitwise +(binary) expansion of IHIS determines which material properties are to be read: +IHIS = 𝑎4 × 16 + 𝑎3 × 8 + 𝑎2 × 4 + 𝑎1 × 2 + 𝑎0, +where each 𝑎𝑖 is a binary flag set to either 1 or 0. The 𝑎𝑖 are interpreted according to the +following table. +Flag +Description +Variables +𝑎0 Material directions +Anisotropic stiffness +𝑞1, 𝑞2 +Cij +Anisotropic constants +𝑟00, 𝑟45, 𝑟90 +Stress-strain Curve +LCSS +Strength limits +XT, XC, YT, YC, SXY +𝑎1 +𝑎2 +𝑎3 +𝑎4 +# +2 +21 +3 +1 +5 +The NHISV field on *INITIAL_STRESS_SHELL must be set equal to the sum of the +number of variables to be read in, which depends on IHIS (and the 𝑎𝑖): +NHISV = 2𝑎0 + 21𝑎1 + 3𝑎2 + 𝑎3 + 5𝑎4. +Then, in the following order, *INITIAL_STRESS_SHELL processes the history variables, +HISVi, as: +5. +6. +7. +8. +9. +2 material direction parameters when 𝑎0 = 1 +21 anisotropic stiffness parameters when 𝑎1 = 1 +3 anisotropic constants when 𝑎2 = 1 +1 parameters when 𝑎3 = 1 +5 strength parameters when 𝑎4 = 1 +The 𝑞𝑖 terms are the material direction cosine and sinus for the rotation from a co- +rotational element’s system to the 𝑎-𝑏-𝑐 material directions. The 𝑐𝑖𝑗 terms are the upper +triangular terms of the symmetric stiffness matrix, 𝑐11, 𝑐12, 𝑐13, 𝑐14, 𝑐15, 𝑐16, 𝑐22, 𝑐23, 𝑐24, +𝑐25, 𝑐26, 𝑐33, 𝑐34, 𝑐35, 𝑐36, 𝑐44, 𝑐45, 𝑐46, 𝑐55, 𝑐56, and 𝑐66. +Tsai-Wu failure criterion (EXTRA = 1): +Brittle failure with different strengths in tension and compression in all main material +directions can be invoked with EXTRA = 1 and the definition of corresponding +parameters on Cards 8 and 9. The model used is the phenomenological Tsai-Wu failure +criterion which requires that ++ +XT ⋅ XC +( +− +− +XT +YC +) 𝜎𝑎𝑎 + ( +XC +YT ⋅ YC +ZC +SYZ2 𝜎𝑏𝑐 ++2 ⋅ 𝐹12 ⋅ 𝜎𝑎𝑎𝜎𝑏𝑏 + 2 ⋅ 𝐹23 ⋅ 𝜎𝑏𝑏𝜎𝑐𝑐 + 2 ⋅ 𝐹31 ⋅ 𝜎𝑐𝑐𝜎𝑎𝑎 < 1 +YT +ZT ⋅ ZC +SXY2 𝜎𝑎𝑏 +) 𝜎𝑏𝑏 + ( +ZT +) 𝜎𝑐𝑐 +2 + +2 + +2 + +2 + +𝜎𝑏𝑏 +𝜎𝑐𝑐 +− +𝜎𝑎𝑎 +2 + +2 +SZX2 𝜎𝑐𝑎 +for the 3-dimensional case (solid elements) with three planes of symmetry with respect +to the material coordinate system. The interaction terms 𝐹12, 𝐹23, and 𝐹31 are given by +𝐹12 = FF12 ⋅ √ +ZT⋅ZC⋅XT⋅XC +For the 2-dimensional case of plane stress (shell elements) this expression reduces to: +XT⋅XC⋅YT⋅YC , 𝐹23 = FF23 ⋅ √ +YT⋅YC⋅ZT⋅ZC , 𝐹31 = FF31 ⋅ √ +( +XT +− +XC +) 𝜎𝑎𝑎 + ( +YC +) 𝜎𝑏𝑏 + +XT ⋅ XC +2 + +𝜎𝑎𝑎 +YT ⋅ YC +2 +𝜎𝑏𝑏 +− +YT +SXY2 𝜎𝑎𝑏 ++ +2 + 2 ⋅ 𝐹12 ⋅ 𝜎𝑎𝑎𝜎𝑏𝑏 < 1 +If these conditions are violated, then the stress tensor will be reduced to zero over +NCFAIL time steps and then the element gets eroded. A small value for NCFAIL (< 50) +is recommended to avoid unphysical behavior, the default is 10. The default values for +the strengths XT, XC, YT, YC, ZT, ZC, SXY, SYZ, and SZX are 1e20, i.e. basically no +limits. The scale factors FF12, FF23, and FF31 for the interaction terms are zero by +default. +Tsai-Hill failure criterion (EXTRA = 2): +Brittle failure with different strengths in tension and compression in all main material +directions can be invoked with EXTRA = 2 and the definition of corresponding +parameters on Cards 8 and 9 (FF12, FF23 and FF31 are not used in this model). The +model based on the HILL criterion which can be written as +(G + H)σaa +2 + (F + H)σbb +2 + 2Mσca +2 + (F + G)σcc +2 < 1 +2 + 2Lσbc ++2Nσab +2 − 2Hσaaσbb − 2F σbbσcc − 2Gσccσaa +for the 3-dimensional case. The constants H,F,G,N,L,M can be expressed in terms of the +strength limits (which then becomes the TSAI-HILL criterion), where the current stress +state defines whether the compressive or the tensile strength limit will enter into the +equation: +G + H = +2 ; F + H = +Xi +2 ; F + G = +Yi +2 ; 2𝑁 = +Zi +𝑆𝑋𝑌2 ; 2𝐿 = +𝑆𝑌𝑍2 ; 2𝑁 += +𝑆𝑍𝑋2 +2 − 1 +2 + 1 +2) ; G= 0.5 ⋅ ( 1 +2 − 1 +2 + 1 +2) ; F= 0.5 ⋅ ( 1 +2 − 1 +2 + 1 +H= 0.5 ⋅ ( 1 +2) +𝑌𝑖 +𝑍𝑖 +𝑋𝑖 +𝑋𝑖 +𝑍𝑖 +𝑌𝑖 +𝑍𝑖 +𝑌𝑖 +𝑋𝑖 +𝑋𝑖 = { +𝑋𝑇 𝑖𝑓 𝜎𝑎𝑎 > 0 +𝑋𝐶 𝑖𝑓 𝜎𝑎𝑎 < 0 + ; 𝑌𝑖 = { +𝑌𝑇 𝑖𝑓 𝜎𝑏𝑏 > 0 +𝑌𝐶 𝑖𝑓 𝜎𝑏𝑏 < 0 + ; 𝑍𝑖 = { +𝑍𝑇 𝑖𝑓 𝜎𝑐𝑐 > 0 +𝑍𝐶 𝑖𝑓 𝜎𝑐𝑐 < 0 +For the 2-dimensional case of plane stress (shell elements) the TSAI-HILL criterion +reduces to: +(G + H)σaa +2 + (F + H)σbb +2 − 2Hσaaσbb + 2Nσab +2 < 1 +with +G + H = +2 ; F + H = +Xi +2 ; H = 0.5 ⋅ ( +Yi +2) ; 2𝑁 = +Xi +𝑆𝑋𝑌2 +If these conditions are violated, then the stress tensor will be reduced to zero over +NCFAIL time steps and then the element gets eroded. A small value for NCFAIL (< 50) +is recommended to avoid unphysical behavior, the default is 10. The default values for +the strengths XT, XC, YT, YC, ZT, ZC, SXY, SYZ, and SZX are 1e20, i.e. basically no +limits. +*MAT_RATE_SENSITIVE_COMPOSITE_FABRIC +This is Material Type 158. Depending on the type of failure surface, this model may be +used to model rate sensitive composite materials with unidirectional layers, complete +laminates, and woven fabrics. A viscous stress tensor, based on an isotropic Maxwell +model with up to six terms in the Prony series expansion, is superimposed on the rate +independent stress tensor of the composite fabric. The viscous stress tensor approach +should work reasonably well if the stress increases due to rate affects are up to 15% of +the total stress. This model is implemented for both shell and thick shell elements. The +viscous stress tensor is effective at eliminating spurious stress oscillations. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +EA +F +3 +4 +EB +F +4 +5 +6 +7 +8 +(EC) +PRBA +TAU1 +GAMMA1 +F +5 +F +6 +F +7 +F +8 +Variable +GAB +GBC +GCA +SLIMT1 +SLIMC1 +SLIMT2 +SLIMC2 +SLIMS +Type +F + Card 3 +1 +F +2 +F +3 +F +4 +Variable +AOPT +TSIZE +ERODS +SOFT +Type +F +F +F +F + Card 4 +Variable +1 +XP +Type +F +2 +YP +F +3 +ZP +F +4 +A1 +F +F +5 +FS +F +5 +A2 +F +F +6 +6 +A3 +F +F +7 +F +8 +7 +8 +PRCA +PRCB +F +Card 5 +Variable +1 +V1 +Type +F + Card 6 +1 +2 +V2 +F +2 +3 +V3 +F +3 +4 +D1 +F +4 +5 +D2 +F +5 +6 +D3 +F +6 +7 +8 +BETA +F +7 +8 +Variable +E11C +E11T +E22C +E22T +GMS +Type +F +F +F +F +F +2 +XT +F +2 +3 +YC +F +3 +4 +YT +F +4 +5 +SC +F +5 +6 +7 +8 +6 +7 +8 + Card 7 +Variable +1 +XC +Type +F + Card 8 +Variable +Type +1 +K +F +Viscoelastic Cards. Up to 6 cards may be input. A keyword card (with a “*” in +column 1) terminates this input if less than 6 cards are used. + Optional +Variable +Type +1 +GI +F +2 +3 +4 +5 +6 +7 +8 +BETAI +*MAT_RATE_SENSITIVE_COMPOSITE_FABRIC +DESCRIPTION +MID +RO +EA +EB +(EC) +PRBA +PRCA +PRCB +TAU1 +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Ea, Young’s modulus - longitudinal direction +Eb, Young’s modulus - transverse direction +Ec, Young’s modulus - normal direction (not used) +ba, Poisson’s ratio ba +ca, Poisson’s ratio ca, can be defined in card 4, col. 7, +default = PRBA +cb, Poisson’s ratio cb, can be defined in card 4, col. 8, +default = PRBA +τ1, stress limit of the first slightly nonlinear part of the shear stress +versus shear strain curve. The values τ1 and γ1 are used to define +a curve of shear stress versus shear strain. These values are input +if FS, defined below, is set to a value of -1. +GAMMA1 +γ1, strain limit of the first slightly nonlinear part of the shear stress +versus shear strain curve. +GAB +GBC +GCA +SLIMT1 +SLIMC1 +SLIMT2 +SLIMC2 +Gab, shear modulus ab +Gbc, shear modulus bc +Gca, shear modulus ca +Factor to determine the minimum stress limit after stress +maximum (fiber tension). +Factor to determine the minimum stress limit after stress +maximum (fiber compression). +Factor to determine the minimum stress limit after stress +maximum (matrix tension). +Factor to determine the minimum stress limit after stress +maximum (matrix compression). +VARIABLE +DESCRIPTION +SLIMS +AOPT +Factor to determine the minimum stress limit after stress +maximum (shear). +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the shell ele- +ment normal by the angle BETA. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle (BETA) from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +TSIZE +Time step for automatic element deletion. +ERODS +Maximum effective strain for element layer failure. A value of +unity would equal 100% strain. +SOFT +Softening reduction factor for strength in the crashfront. +FS +Failure surface type: +EQ.1.0: smooth failure surface with a quadratic criterion for +both the fiber (a) and transverse (b) directions. This +option can be used with complete laminates and fab- +rics. +EQ.0.0: smooth failure surface in the transverse (b) direction +with a limiting value in the fiber (a) direction. This +model is appropriate for unidirectional (UD) layered +composites only. +EQ.-1: faceted failure surface. When the strength values are +reached then damage evolves in tension and compres- +*MAT_RATE_SENSITIVE_COMPOSITE_FABRIC +DESCRIPTION +sion for both the fiber and transverse direction. Shear +behavior is also considered. This option can be used +with complete laminates and fabrics. +XP, YP, ZP +Define coordinates of point p for AOPT = 1. +A1, A2, A3 +Define components of vector a for AOPT = 2. +V1, V2, V3 +Define components of vector v for AOPT = 3. +D1, D2, D3 +Define components of vector d for AOPT = 2. +BETA +E11C +E11T +E22C +E22T +GMS +XC +XT +YC +YT +SC +K +GI +Material angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA. +Strain at longitudinal compressive strength, a-axis. +Strain at longitudinal tensile strength, a-axis. +Strain at transverse compressive strength, b-axis. +Strain at transverse tensile strength, b-axis. +Strain at shear strength, ab plane. +Longitudinal compressive strength +Longitudinal tensile strength, see below. +Transverse compressive strength, b-axis, see below. +Transverse tensile strength, b-axis, see below. +Shear strength, ab plane. +Optional bulk modulus for the viscoelastic material. If nonzero a +Kelvin type behavior will be obtained. Generally, K is set to zero. +Optional shear relaxation modulus for the ith term +BETAI +Optional shear decay constant for the ith term +Remarks: +See the remark for material type 58, *MAT_LAMINATED_COMPOSITE_FABRIC, for +the treatment of the composite material. +Rate effects are taken into account through a Maxwell model using linear viscoelasticity +by a convolution integral of the form: +𝜎𝑖𝑗 = ∫ 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) +∂𝜀𝑘𝑙 +∂𝜏 +𝑑𝜏 +where 𝑔𝑖𝑗𝑘𝑙(𝑡−𝜏) is the relaxation functions for the different stress measures. This stress is +added to the stress tensor determined from the strain energy functional. Since we wish +to include only simple rate effects, the relaxation function is represented by six terms +from the Prony series: +𝑔(𝑡) = ∑ 𝐺𝑚𝑒−𝛽𝑚𝑡 +𝑚=1 +We characterize this in the input by the shear moduli, 𝐺𝑖, and decay constants, 𝛽𝑖. An +arbitrary number of terms, not exceeding 6, may be used when applying the viscoelastic +model. The composite failure is not directly affected by the presence of the viscous +stress tensor. +*MAT_CSCM +This is material type 159. This is a smooth or continuous surface cap model and is +available for solid elements in LS-DYNA. The user has the option of inputting his own +material properties ( option), or requesting default material properties for +normal strength concrete (CONCRETE). +Available options include: + +CONCRETE + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +RO +NPLOT +INCRE +IRATE +ERODE +RECOV +ITRETRC +F +2 +I +3 +F +4 +I +5 +F +6 +F +7 +I +8 +Type +A8 + Card 2 +1 +Variable +PRED +Type +F +Card 3 for CONCRETE keyword option. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FPC +DAGG +UNITS +Type +F +F +The remaining cards are read when the keyword option is left blank. They are not read +in when CONCRETE keyword option is active. + Card 3 +Variable +Type +1 +G +F + Card 4 +1 +2 +K +F +2 +3 +4 +5 +6 +ALPHA +THETA +LAMDA +BETA +F +3 +F +4 +F +5 +F +6 +7 +NH +F +7 +8 +CH +F +8 +Variable +ALPHA1 +THETA1 +LAMDA1 +BETA1 +ALPHA2 +THETA2 +LAMDA2 +BETA2 +Type +F +F + Card 5 +Variable +Type + Card 6 +Variable +Type +1 +R +F +1 +B +F + Card 7 +1 +2 +X0 +F +2 +GFC +F +2 +F +3 +W +F +3 +D +F +3 +Variable +ETA0C +NC +ETA0T +Type +F +F +F +F +F +4 +D1 +F +4 +5 +D2 +F +5 +F +6 +F +7 +F +8 +6 +7 +8 +GFT +GFS +PWRC +PWRT +PMOD +F +4 +NT +F +F +5 +F +6 +F +7 +F +8 +OVERC +OVERT +SRATE +REPOW +F +F +F +MID +*MAT_CSCM +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +NPLOT +Controls what is written as component 7 to the d3plot database. +LS-Prepost always blindly labels this component as effective +plastic strain: +EQ.1: Maximum of brittle and ductile damage (default). +EQ.2: Maximum of brittle and ductile damage, with recovery +of brittle damage. +EQ.3: Brittle damage. +EQ.4: Ductile damage. +EQ.5: κ (intersection of cap with shear surface). +EQ.6: X0 (intersection of cap with pressure axis). +EQ.7: 𝜀v +p (plastic volume strain). +INCRE +Maximum strain increment for subincrementation. If left blank, a +default value is set during initialization based upon the shear +strength and stiffness. +IRATE +Rate effects options: +EQ.0: Rate effects model turned off (default). +EQ.1: Rate effects model turned on. +ERODE +Elements erode when damage exceeds 0.99 and the maximum +principal strain exceeds ERODE-1.0. + For erosion that is +independent of strain, set ERODE equal to 1.0. Erosion does not +occur if ERODE is less than 1.0. +RECOV +*MAT_159 +DESCRIPTION +The modulus is recovered in compression when RECOV is equal +to 0 (default). The modulus remains at the brittle damage level +when RECOV is equal to 1. Partial recovery is modeled for +values of RECOV between 0 and 1. Two options are available: +EQ.1: Input a value between 0 and 1. Recovery is based upon +the sign of the pressure invariant only. +EQ.2: Input a value between 10 and 11. Recovery is based +upon the sign of both the pressure and volumetric strain. +In this case, RECOV = RECOV-10, and a flag is set to +request the volumetric strain check. +IRETRC +Cap retraction option: +EQ.0: Cap does not retract (default). +EQ.1: Cap retracts. +PRED +Pre-existing damage (0 ≤ PreD < 1). If left blank, the default is +zero (no pre-existing damage). +Define for the CONCRETE option only: + VARIABLE +FPC +DESCRIPTION +Unconfined compression strength, f 'C. Material parameters are +internally fit to data for unconfined compression strengths +between about 20 and 58 Mpa (2,901 to 8,412 psi), with emphasis +on the midrange between 28 and 48 MPa (4,061 and 6,962 psi). If +left blank, default for FPC is 30 MPa. +DAGG +Maximum aggregate size, Dagg. Softening is fit to data for +aggregate sizes between 8 and 32 mm (0.3 and 1.3 inches). If left +blank, default for DAGG is 19 mm (3/4 inch). +UNITS +Units options: +EQ.0: GPa, mm, msec, Kg/mm3, kN +EQ.1: MPa, mm, msec, g/mm3, N +EQ.2: MPa, mm, sec, Mg/mm3, N +EQ.3: Psi, inch, sec, lbf-s2/inch4, lbf +EQ.4: Pa, m, sec, kg/m3, N +*MAT_CSCM + VARIABLE +DESCRIPTION +G +K +ALPHA +THETA +Shear modulus. +Bulk modulus. +Tri-axial compression surface constant term, α. +Tri-axial compression surface linear term, θ. +LAMDA +Tri-axial compression surface nonlinear term, λ. +BETA +Tri-axial compression surface exponent, β. +ALPHA1 +Torsion surface constant term, α1. +THETA1 +Torsion surface linear term, θ1. +LAMDA1 +Torsion surface nonlinear term, λ1. +BETA1 +Torsion surface exponent, β1. +ALPHA2 +Tri-axial extension surface constant term, α2. +THETA2 +Tri-axial extension surface linear term, θ2. +LAMDA2 +Tri-axial extension surface nonlinear term, λ2. +BETA2 +Tri-axial extension surface exponent, β2. +NH +CH +R +X0 +W +D1 +D2 +B +Hardening initiation, NH. +Hardening rate, CH. +Cap aspect ratio, R. +Cap initial location, X0. +Maximum plastic volume compaction, W. +Linear shape parameter, D1. +Quadratic shape parameter, D2. +Ductile shape softening parameter, B. +VARIABLE +GFC +D +GFT +GFS +PWRC +PWRT +DESCRIPTION +Fracture energy in uniaxial stress Gfc. +Brittle shape softening parameter, D. +Fracture energy in uniaxial tension, Gft. +Fracture energy in pure shear stress, Gfs. +Shear-to-compression transition parameter. +Shear-to-tension transition parameter. +PMOD +Modify moderate pressure softening parameter. +ETA0C +Rate effects parameter for uniaxial compressive stress, η0c. +NC +Rate effects power for uniaxial compressive stress, NC. +ETA0T +Rate effects parameter for uniaxial tensile stress, η0t. +NT +Rate effects power for uniaxial tensile stress, Nt. +OVERC +Maximum overstress allowed in compression. +OVERT +Maximum overstress allowed in tension. +SRATE +Ratio of effective shear stress to tensile stress fluidity parameters. +REPOW +Power which increases fracture energy with rate effects. +Model Formulation and Input Parameters: +Shear Surface +Smooth Intersection +Cap +Pressure +Figure M159-1. General shape of concrete model yield surface in two +dimensions. +This is a cap model with a smooth intersection between the shear yield surface and +hardening cap, as shown in Figure M159-1. The initial damage surface coincides with +the yield surface. Rate effects are modeled with viscoplasticity. For a complete +theoretical description, with references and example problems see [Murray 2007] and +[Murray, Abu-Odeh and Bligh 2007]. +Stress Invariants. The yield surface is formulated in terms of three stress invariants: 𝐽1 is +′ is the second invariant of the deviatoric stress +the first invariant of the stress tensor, 𝐽2 +′ is the third invariant of the deviatoric stress tensor. The invariants are +tensor, and 𝐽3 +defined in terms of the deviatoric stress tensor, Sij and pressure, P, as follows: +𝐽1 = 3P +′ = +𝐽2 +′ = +𝐽3 +SijSij +SijSjkSki +Plasticity Surface. The three invariant yield function is based on these three invariants, +and the cap hardening parameter, κ, as follows: +′ , 𝜅) = 𝐽2 +Here 𝐹f is the shear failure surface, 𝐹c is the hardening cap, and ℜ is the Rubin three- +invariant reduction factor. The cap hardening parameter 𝜅 is the value of the pressure +invariant at the intersection of the cap and shear surfaces. +′ − ℜ2𝐹𝑓 +𝑓 (𝐽1, 𝐽2 +2𝐹𝑐 +′ , 𝐽3 +Trial elastic stress invariants are temporarily updated via the trial elastic stress tensor, +′𝑇. Elastic stress states are modeled when +𝝈𝑇. These are denoted J1 +′𝑇, 𝜅𝑇) ≤ +𝑓 (𝐽1 +′𝑇, 𝜅𝑇) ≤ 0. Elastic-plastic stress states are modeled when 𝑓 (𝐽1 +′𝑇, and J3 +𝑇, J2 +′𝑇, 𝐽3 +′𝑇, 𝐽3 +𝑇, 𝐽2 +𝑇, 𝐽2 +0. In this case, the plasticity algorithm returns the stress state to the yield surface such +′𝑃, 𝜅𝑃) = 0. This is accomplished by enforcing the plastic consistency +that 𝑓 (𝐽1 +condition with associated flow. +′𝑃, 𝐽3 +𝑃, 𝐽2 +Shear Failure Surface. The strength of concrete is modeled by the shear surface in the +tensile and low confining pressure regimes: +𝐹𝑓 (J1) = 𝛼 − 𝜆 exp−𝛽 J1 + 𝜃𝐽1 +Here the values of 𝛼, 𝛽, 𝜆, and 𝜃 are selected by fitting the model surface to strength +measurements from triaxial compression (TXC) tests conducted on plain concrete +cylinders. +′ (principal stress +Rubin Scaling Function. Concrete fails at lower values of √3𝐽2 +difference) for triaxial extension (TXE) and torsion (TOR) tests than it does for TXC tests +conducted at the same pressure. The Rubin scaling function ℜ determines the strength +of concrete for any state of stress relative to the strength for TXC, via ℜFf. Strength in +torsion is modeled as Q1Ff . Strength in TXE is modeled as Q2Ff, where: +𝑄1 = 𝛼1 − 𝜆1exp−𝛽1J1 + 𝜃1𝐽1 +𝑄2 = 𝛼2 − 𝜆2exp−𝛽2J1 + 𝜃2𝐽1 +Cap Hardening Surface. The strength of concrete is modeled by a combination of the cap +and shear surfaces in the low to high confining pressure regimes. The cap is used to +model plastic volume change related to pore collapse (although the pores are not +explicitly modeled). The isotropic hardening cap is a two-part function that is either +unity or an ellipse: +𝐹𝑐( 𝐽1, 𝜅 ) = 1 − +[𝐽1 − 𝐿 (𝜅)][ |𝐽1 − 𝐿(𝜅)| + 𝐽1 − 𝐿(𝜅) ] +2 [𝑋(𝜅) − 𝐿 (𝜅)] 2 +where 𝐿(𝜅) is defined as: +𝐿(𝜅) = { +if 𝜅 > 𝜅0 +𝜅0 otherwise +The equation for 𝐹𝑐 is equal to unity for 𝐽1 ≤ 𝐿(𝜅). It describes the ellipse for J1 > L(κ). +The intersection of the shear surface and the cap is at J1 = κ. κ0 is the value of J1 at the +initial intersection of the cap and shear surfaces before hardening is engaged (before the +cap moves). The equation for L(κ) restrains the cap from retracting past its initial +location at κ0. +The intersection of the cap with the J1 axis is at J1 = X(κ). This intersection depends +upon the cap ellipticity ratio R, where R is the ratio of its major to minor axes: +𝑋(𝜅) = 𝐿(𝜅) + R𝐹𝑓 [𝐿(𝜅)] +The cap expands (X(κ) +The cap moves to simulate plastic volume change. +and κ increase) to simulate plastic volume compaction. The cap contracts (X(κ) and κ +decrease) to simulate plastic volume expansion, called dilation. The motion (expansion +and contraction) of the cap is based upon the hardening rule: +𝑝 = 𝑊[1 − 𝑒−𝐷1(𝑋−𝑋0)−𝐷2(𝑋−𝑋0)2 +𝜀𝑣 +] +p the plastic volume strain, W is the maximum plastic volume strain, and D1 and +Here 𝜀v +D2 are model input parameters. X0 is the initial location of the cap when κ = κ0. +The five input parameters (X0, W, D1, D2, and R) are obtained from fits to the pressure- +volumetric strain curves in isotropic compression and uniaxial strain. X0 determines the +pressure at which compaction initiates in isotropic compression. R, combined with X0, +determines the pressure at which compaction initiates in uniaxial strain. D1, and D2 +determine the shape of the pressure-volumetric strain curves. W determines the +maximum plastic volume compaction. +Shear Hardening Surface. In unconfined compression, the stress-strain behavior of +concrete exhibits nonlinearity and dilation prior to the peak. Such behavior is be +modeled with an initial shear yield surface, NHFf , which hardens until it coincides with +the ultimate shear yield surface, Ff. Two input parameters are required. One +parameter, NH, initiates hardening by setting the location of the initial yield surface. A +second parameter, CH, determines the rate of hardening (amount of nonlinearity). +Damage. Concrete exhibits softening in the tensile and low to moderate compressive +regimes. +d = (1 − 𝑑)𝜎ij +𝜎ij +vp +A scalar damage parameter, d, transforms the viscoplastic stress tensor without +damage, denoted σvp, into the stress tensor with damage, denoted σd. Damage +accumulation is based upon two distinct formulations, which we call brittle damage +and ductile damage. The initial damage threshold is coincident with the shear plasticity +surface, so the threshold does not have to be specified by the user. +Ductile Damage. Ductile damage accumulates when the pressure (P) is compressive and +an energy-type term, τc, exceeds the damage threshold, τ0c. + Ductile damage +accumulation depends upon the total strain components, εij, as follows: +The stress components σij are the elasto-plastic stresses (with kinematic hardening) +calculated before application of damage and rate effects. +𝜏c = √ +𝜎𝑖𝑗𝜀𝑖𝑗 +Brittle Damage. Brittle damage accumulates when the pressure is tensile and an energy- +type term, τt, exceeds the damage threshold, τ0t. Brittle damage accumulation depends +upon the maximum principal strain, ε max, as follows: +Softening Function. As damage accumulates, the damage parameter d increases from an +initial value of zero, towards a maximum value of one, via the following formulations: +𝜏t = √𝐸 𝜀 max +Brittle Damage: 𝑑(𝜏𝑡) = +Ductile Damage: +𝑑(𝜏𝑐) = +0.999 +𝑑max +1 + 𝐷 + [ +1 + 𝐷 𝑒−𝐶(𝜏𝑡−𝜏0𝑡) − 1] +1 + 𝐵𝑒−𝐴(𝜏𝑐−𝜏0𝑐) − 1] +1 + 𝐵 + [ +The damage parameter that is applied to the six stresses is equal to the current +maximum of the brittle or ductile damage parameter. The parameters A and B or C and +D set the shape of the softening curve plotted as stress-displacement or stress-strain. +The parameter dmax is the maximum damage level that can be attained. It is calculated +internally calculated and is less than one at moderate confining pressures. The +compressive softening parameter, A, may also be reduced with confinement, using the +input parameter pmod, as follows: +𝐴 = 𝐴(𝑑max + 0.001)pmod +Regulating Mesh Size Sensitivity. The concrete model maintains constant fracture +energy, regardless of element size. The fracture energy is defined here as the area +under the stress-displacement curve from peak strength to zero strength. This is done +by internally formulating the softening parameters A and C in terms of the element +length, l (cube root of the element volume), the fracture energy, Gf, the initial damage +threshold, τ0t or τ0c, and the softening shape parameters, D or B. +The fracture energy is calculated from up to five user-specified input parameters: GFC, +GFS, GFT, PWRC, and PWRT. The user specifies three distinct fracture energy values. +These are the fracture energy in uniaxial tensile stress, GFT, pure shear stress, GFS, and +uniaxial compressive stress, GFC. The model internally selects the fracture energy from +equations which interpolate between the three fracture energy values as a function of +the stress state (expressed via two stress invariants). The interpolation equations +depend upon the user-specified input powers PWRC and PWRT, as follows. +Tensile Pressure: 𝐺𝑓 = GFS + +Compressive Pressure: 𝐺𝑓 = GFS + +𝑘𝑡 +⏞⏞⏞⏞⏞⏞⏞ +PWRT +⎜⎜⎜⎛ −𝐽1 +⎟⎟⎟⎞ +′ +√3𝐽2 +⎠ +⎝ +𝑘𝑐 +⏞⏞⏞⏞⏞⏞⏞ +PWRC +⎜⎜⎜⎛ 𝐽1 +⎟⎟⎟⎞ +′ +√3𝐽2 +⎠ +⎝ +[GFT − GFS] +[GFC − GFS] +The internal parameters 𝑘𝑐 and 𝑘𝑡 are restricted to the interval [0,1]. +Element Erosion. An element losses all strength and stiffness as d→1. To prevent +computational difficulties with very low stiffness, element erosion is available as a user +option. An element erodes when d > 0.99 and the maximum principal strain is greater +than a user supplied input value, ERODE-1.0. +Viscoplastic Rate Effects. At each time step, the viscoplastic algorithm interpolates +p, to +between the elastic trial stress, 𝜎𝑖j +set the viscoplastic stress (with rate effects), 𝜎𝑖j +T, and the inviscid stress (without rate effects), 𝜎𝑖j +vp: +vp = (1 − 𝛾)σij +σij +p +T + 𝛾σij +where, +𝛾 = +Δt/𝜂 +1 + Δt/𝜂 +. +This interpolation depends upon the effective fluidity coefficient, η, and the time step, +Δt. The effective fluidity coefficient is internally calculated from five user-supplied +input parameters and interpolation equations: +Tensile Pressure: 𝜂 = 𝜂𝑠 + +Compressive Pressure: +𝜂 = 𝜂𝑠 + +where, +PWRT +⎟⎟⎟⎞ +⎠ +PWRC +⎜⎜⎜⎛ −𝐽1 +′ +√3𝐽2 +⎝ +⎜⎜⎜⎛ 𝐽1 +′ +√3𝐽2 +⎝ +⎟⎟⎟⎞ +⎠ +[𝜂𝑡 − 𝜂𝑠] +[𝜂𝑐 − 𝜂𝑠] +𝜂𝑠 = SRATE × 𝜂𝑡 +𝜂𝑡 = +ETA0T +𝜖 ̇NT +𝜂𝑐 = +ETA0C +𝜖 ̇NC +The input parameters are ΕΤΑ0Τ and NT for fitting uniaxial tensile stress data, ΕΤΑ0Χ +and NC for fitting the uniaxial compressive stress data, and SRATE for fitting shear +stress data. The effective strain rate is 𝜀̇. +This viscoplastic model may predict substantial rate effects at high strain rates (𝜀̇ > 100). +To limit rate effects at high strain rates, the user may input overstress limits in tension +OVERT and compression OVERC. These input parameters limit calculation of the +fluidity parameter, as follows: +if 𝐸𝜖 ̇𝜂 > OVER, then 𝜂 = +𝐸𝜖 ̇ +where m = OVERT when the pressure is tensile, and m = OVERC when the pressure is +compressive. +The user has the option of increasing the fracture energy as a function of effective strain +rate via the REPOW input parameter, as follows: +Gf +rate = Gf (1 + +Eε̇η +f′ +rate is the fracture energy enhanced by rate effects, and f′ is the yield strength +Here Gf +before application of rate effects (which is calculated internally by the model). The term +in brackets is greater than, or equal to one, and is the approximate ratio of the dynamic +to static strength. +) +REPOW +*MAT_ALE_INCOMPRESSIBLE +This is Material Type 160. This card allows to solve incompressible flows with the ALE +solver. It should be used with the element formulation 6 and 12 in *SECTION_SOLID +(elform = 6 or 12). A projection method enforces the incompressibility condition. +5 +6 +7 +8 + Card 1 +1 +Variable +MID +Type +I +2 +RO +F +3 +PC +F +4 +MU +F +Default +none +none +0.0 +0.0 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TOL +DTOUT +NCG +METH +Type +F +F +I +I +Default +1e-8 +1e10 +50 +-7 + VARIABLE +DESCRIPTION +MID +RO +PC +MU +TOL +Material ID. A unique number or label not exceeding 8 charaters +must be specified. Material ID is referenced in the *PART card +and must be unique +Material density +Pressure cutoff (< or = 0.0) +Dynamic viscosity coefficient +Tolerance for the convergence of the conjugate gradient +DTOUT +Time interval between screen outputs +NCG +Maximum number of loops in the conjugate gradient +VARIABLE +DESCRIPTION +METH +Conjugate gradient methods: +EQ.-6: solves the poisson equation for the pressure +EQ.-7: solves the poisson equation for the pressure increment +*MAT_COMPOSITE_MSC_{OPTION} +Available options include: + +DMG +These are Material Types 161 and 162. These models may be used to model the +progressive failure analysis for composite materials consisting of unidirectional and +woven fabric layers. The progressive layer failure criteria have been established by +adopting the methodology developed by Hashin [1980] with a generalization to include +the effect of highly constrained pressure on composite failure. These failure models can +be used to effectively simulate fiber failure, matrix damage, and delamination behavior +under all conditions - opening, closure, and sliding of failure surfaces. The model with +DMG option (material 162) is a generalization of the basic layer failure model of +Material 161 by adopting the damage mechanics approach for characterizing the +softening behavior after damage initiation. These models require an additional license +from Materials Sciences Corporation, which developed and supports these models. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +EA +F +3 +4 +EB +F +4 +5 +EC +F +5 +Variable +GAB +GBC +GCA +AOPT +MACF +Type +F +F +F +F +I + Card 3 +Variable +1 +XP +Type +F +2 +YP +F +3 +ZP +F +4 +A1 +F +5 +A2 +F +6 +7 +8 +PRBA +PRCA +PRCB +F +7 +F +8 +7 +8 +F +6 +6 +A3 +Card 4 +Variable +1 +V1 +Type +F + Card 5 +1 +2 +V2 +F +2 +3 +V3 +F +3 +4 +D1 +F +4 +5 +D2 +F +5 +6 +D3 +F +6 +7 +8 +BETA +F +7 +8 +Variable +SAT +SAC +SBT +SBC +SCT +SFC +SFS +SAB +Type +F + Card 6 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +Variable +SBC +SCA +SFFC +AMODEL +PHIC +E_LIMT +S_DELM +Type +F + Card 7 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +8 +Variable +OMGMX +ECRSH +EEXPN +CERATE1 +AM1 +Type +F +F +F +F +F +Failure Card. Additional card for DMG keyword option. + Card 8 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +AM2 +AM3 +AM4 +CERATE2 CERATE3 CERATE4 +Type +F +F +F +F +F +F + VARIABLE +MID +LS-DYNA R10.0 +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +RO +EA +EB +EC +PRBA +PRCA +PRCB +GAB +GBC +GCA +Mass density +Ea, Young’s modulus - longitudinal direction +Eb, Young’s modulus - transverse direction +Ec, Young’s modulus - through thickness direction +ba, Poisson’s ratio ba +ca, Poisson’s ratio ca +cb, Poisson’s ratio cb +Gab, shear modulus ab +Gbc, shear modulus bc +Gca, shear modulus ca +AOPT +Material axes option, see Figure 2.1: +EQ.0.0: locally orthotropic with material axes determined by +element nodes as shown in Figure 2.1. Nodes 1, 2, and +4 of an element are identical to the Nodes used for the +definition of a coordinate system by *DEFINE_COOR- +DINATE_NODES. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center, to define the a-direction. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. The plane of a solid element is the +midsurface between the inner surface and outer surface +defined by the first four nodes and the last four nodes +of the connectivity of the element, respectively. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector v, and +an originating point, p, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +MACF +Material axes change flag: +EQ.1: No change, default, +EQ.2: switch material axes a and b, +EQ.3: switch material axes a and c, +EQ.4: switch material axes b and c. +XP, YP, ZP +Define coordinates of point p for AOPT = 1 and 4. +A1, A2, A3 +Define components of vector a for AOPT = 2. +V1, V2, V3 +Define components of vector v for AOPT = 3 and 4. +D1, D2, D3 +Define components of vector d for AOPT = 2. +BETA +Layer in-plane rotational angle in degrees. +SAT +SAC +SBT +SBC +SCT +SFC +SFS +SAB +SBC +SCA +Longitudinal tensile strength +Longitudinal compressive strength +Transverse tensile strength +Transverse compressive strength +Through thickness tensile strength +Crush strength +Fiber mode shear strength +Matrix mode shear strength, ab plane, see below. +Matrix mode shear strength, bc plane, see below. +Matrix mode shear strength, ca plane, see below. +SFFC +Scale factor for residual compressive strength +AMODEL +Material models: +EQ.1.0: Unidirectional layer model +EQ.2.0: Fabric layer model +PHIC +Coulomb friction angle for matrix and delamination failure, < 90 +E_LIMT +Element eroding axial strain +S_DELM +Scale factor for delamination criterion +OMGMX +Limit damage parameter for elastic modulus reduction +ECRSH +Limit compressive volume strain for element eroding +EEXPN +Limit tensile volume strain for element eroding +CERATE1 +Coefficient for strain rate dependent strength properties +AM1 +AM2 +AM3 +AM4 +Coefficient for strain rate softening property for fiber damage in a +direction. +Coefficient for strain rate softening property for fiber damage in b +direction. +Coefficient for strain rate softening property for fiber crush and +punch shear damage. +Coefficient for strain rate softening property for matrix and +delamination damage. +CERATE2 +Coefficient for strain rate dependent axial moduli. +CERATE3 +Coefficient for strain rate dependent shear moduli. +CERATE4 +Coefficient for strain rate dependent transverse moduli. +Material Models: +in +The unidirectional and fabric layer failure criteria and the associated property +degradation models for material 161 are described as follows. All the failure criteria are +expressed +stresses +(𝜎𝑎, 𝜎𝑏, 𝜎𝑐, 𝜏𝑎𝑏, 𝜏𝑏𝑐, 𝜏𝑐𝑎) and the associated elastic moduli are (𝐸𝑎, 𝐸𝑏, 𝐸𝑐, 𝐺𝑎𝑏, 𝐺𝑏𝑐, 𝐺𝑐𝑎). +Note that for the unidirectional model, a, b and c denote the fiber, in-plane transverse +and out-of-plane directions, respectively, while for the fabric model, a, b and c denote +the in-plane fill, in-plane warp and out-of-plane directions, respectively. +components based on ply +terms of +stress +level +Unidirectional lamina model: +Three criteria are used for fiber failure, one in tension/shear, one in compression and +another one in crush under pressure. They are chosen in terms of quadratic stress +forms as follows: +Tensile/shear fiber mode: +𝑓1 = ( +) +〈𝜎𝑎〉 +𝑆𝑎𝑇 ++ ( +2 + 𝜏𝑐𝑎 +𝜏𝑎𝑏 +𝑆𝐹𝑆 +) − 1 = 0 +Compression fiber mode: +Crush mode: +𝑓2 = ( +) +′〉 +〈𝜎𝑎 +𝑆𝑎𝐶 +− 1 = 0, +𝜎𝑎 +′ = −𝜎𝑎 + ⟨− +𝜎𝑏 + 𝜎𝑐 +⟩ +𝑓3 = ( +⟨𝑝⟩ +𝑆𝐹𝐶 +) +− 1 = 0, +𝑝 = − +𝜎𝑎 + 𝜎𝑏 + 𝜎𝑐 +⟩ are Macaulay brackets, 𝑆𝑎𝑇 and 𝑆𝑎𝐶 are the tensile and compressive strengths +where ⟨ +in the fiber direction, and 𝑆𝐹𝑆 and 𝑆𝐹𝐶 are the layer strengths associated with the fiber +shear and crush failure, respectively. +Matrix mode failures must occur without fiber failure, and hence they will be on planes +parallel to fibers. For simplicity, only two failure planes are considered: one is +perpendicular to the planes of layering and the other one is parallel to them. The matrix +failure criteria for the failure plane perpendicular and parallel to the layering planes, +respectively, have the forms: +Perpendicular matrix mode: +𝑓4 = ( +) +⟨𝜎𝑏⟩ +𝑆𝑏𝑇 ++ ( +𝜏𝑏𝑐 +′ ) +𝑆𝑏𝑐 ++ ( +) +𝜏𝑎𝑏 +𝑆𝑎𝑏 +− 1 = 0 +Parallel matrix mode (Delamination): +( +𝑓5 = 𝑆2 +𝜏𝑏𝑐 +" +𝑆𝑏𝑐 +where SbT is the transverse tensile strength. Based on the Coulomb-Mohr theory, the +shear strengths for the transverse shear failure and the two axial shear failure modes are +assumed to be the forms, +⟨𝜎𝑐⟩ +𝑆𝑏𝑇 +− 1 = 0 +𝜏𝑐𝑎 +𝑆𝑐𝑎 ++ ( ++ ( +) +) +) +}⎫ +⎭}⎬ +{⎧ +⎩{⎨ +𝑆𝑎𝑏 = 𝑆𝑎𝑏 +′ = 𝑆𝑏𝑐 +𝑆𝑏𝑐 +𝑆𝑐𝑎 = 𝑆𝑐𝑎 +(0) + tan(𝜑)⟨−𝜎𝑏⟩ +(0) + tan(𝜑)⟨−𝜎𝑏⟩ +(0) + tan(𝜑)⟨−𝜎𝑐⟩ +" = 𝑆𝑏𝑐 +𝑆𝑏𝑐 +(0) + tan(𝜑)⟨−𝜎𝑐⟩ +where ϕ is a material constant as tan(𝜑) is similar to the coefficient of friction, and 𝑆𝑎𝑏 +(0)are the shear strength values of the corresponding tensile modes. +(0)and 𝑆𝑏𝑐 +𝑆𝑐𝑎 +(0), +Failure predicted by the criterion of f4 can be referred to as transverse matrix failure, +while the matrix failure predicted by f5, which is parallel to the layer, can be referred as +the delamination mode when it occurs within the elements that are adjacent to the ply +interface. Note that a scale factor S is introduced to provide better correlation of +delamination area with experiments. The scale factor S can be determined by fitting the +analytical prediction to experimental data for the delamination area. +When fiber failure in tension/shear mode is predicted in a layer by f1, the load carrying +capacity of that layer is completely eliminated. All the stress components are reduced +to zero instantaneously (100 time steps to avoid numerical instability). For compressive +fiber failure, the layer is assumed to carry a residual axial load, while the transverse +load carrying capacity is reduced to zero. When the fiber compressive failure mode is +reached due to f2, the axial layer compressive strength stress is assumed to reduce to a +residual value 𝑆𝑅𝐶 (=SFFC × 𝑆𝐴𝐶). The axial stress is then assumed to remain constant, +i.e., 𝜎𝑎 = −𝑆𝑅𝐶, for continuous compressive loading, while the subsequent unloading +curve follows a reduced axial modulus to zero axial stress and strain state. When the +fiber crush failure occurs, the material is assumed to behave elastically for compressive +pressure, p > 0, and to carry no load for tensile pressure, p < 0. +(0)and 𝑆𝑏𝑐 +When a matrix failure (delamination) in the a-b plane is predicted, the strength values +(0) are set to zero. This results in reducing the stress components 𝜎𝑐, 𝜏𝑏𝑐 +for 𝑆𝑐𝑎 +and 𝜏𝑐𝑎 to the fractured material strength surface. For tensile mode, 𝜎𝑐 > 0, these stress +components are reduced to zero. For compressive mode, 𝜎𝑐 < 0, the normal stress 𝜎𝑐 is +assumed to deform elastically for the closed matrix crack. Loading on the failure +envelop, the shear stresses are assumed to ‘slide’ on the fractured strength surface +(frictional shear stresses) like in an ideal plastic material, while the subsequent +unloading shear stress-strain path follows reduced shear moduli to the zero shear stress +and strain state for both 𝜏𝑏𝑐 and 𝜏𝑐𝑎 components. +(0)and 𝑆𝑏𝑐 +The post failure behavior for the matrix crack in the a-c plane due to f4 is modeled in +the same fashion as that in the a-b plane as described above. In this case, when failure +(0)are reduced to zero instantaneously. The post fracture response is +occurs, 𝑆𝑎𝑏 +(0)= 0. For tensile mode, +then governed by failure criterion of f5 with 𝑆𝑎𝑏 +𝜎𝑏 > 0, 𝜎𝑏, 𝜏𝑎𝑏 and 𝜏𝑏𝑐 are zero. For compressive mode, 𝜎𝑏 < 0, 𝜎𝑏 is assumed to be +elastic, while 𝜏𝑎𝑏 and 𝜏𝑏𝑐 ‘slide’ on the fracture strength surface as in an ideal plastic +material, and the unloading path follows reduced shear moduli to the zero shear stress +and strain state. It should be noted that 𝜏𝑏𝑐 is governed by both the failure functions +and should lie within or on each of these two strength surfaces. +(0)= 0 and 𝑆𝑏𝑐 +Fabric lamina model: +The fiber failure criteria of Hashin for a unidirectional layer are generalized to +characterize the fiber damage in terms of strain components for a plain weave layer. +The fill and warp fiber tensile/shear failure are given by the quadratic interaction +between the associated axial and shear stresses, i.e. +2 + 𝜏𝑐𝑎 +2 ) +𝑆𝑎𝐹𝑆 +2 ) +2 + 𝜏𝑏𝑐 +𝑆𝑏𝐹𝑆 +⟨𝜎𝑏⟩ +𝑆𝑏𝑇 +⟨𝜎𝑎⟩ +𝑆𝑎𝑇 +− 1 = 0 +− 1 = 0 +𝑓7 = ( +𝑓6 = ( +(𝜏𝑎𝑏 +(𝜏𝑎𝑏 +) ++ ++ +) +where 𝑆𝑎𝑇and 𝑆𝑏𝑇 are the axial tensile strengths in the fill and warp directions, +respectively, and 𝑆𝑎𝐹𝑆 and 𝑆𝑏𝐹𝑆 are the layer shear strengths due to fiber shear failure in +the fill and warp directions. These failure criteria are applicable when the associated 𝜎𝑎 +or 𝜎𝑏 is positive. It is assumed 𝑆𝑎𝐹𝑆= SFS, and +𝑆𝑏𝐹𝑆 = SFS × +𝑆𝑏𝑇 +𝑆𝑎𝑇 +. +When 𝜎𝑎 or 𝜎𝑏is compressive, it is assumed that the in-plane compressive failure in both +the fill and warp directions are given by the maximum stress criterion, i.e. +𝑓8 = [ +′⟩ +⟨𝜎𝑎 +] +𝑆𝑎𝐶 +𝑓9 = [ +] +′⟩ +⟨𝜎𝑏 +𝑆𝑏𝐶 + − 1 = 0, 𝜎𝑎 +′ = −𝜎𝑎 + ⟨−𝜎𝑐⟩ + − 1 = 0, 𝜎𝑏 +′ = −𝜎𝑏 + ⟨−𝜎𝑐⟩ +where 𝑆𝑎𝐶and 𝑆𝑏𝐶 are the axial compressive strengths in the fill and warp directions, +respectively. The crush failure under compressive pressure is +𝑓10 = ( +⟨𝑝⟩ +𝑆𝐹𝐶 +) +− 1 = 0, 𝑝 = − +𝜎𝑎 + 𝜎𝑏 + 𝜎𝑐 +A plain weave layer can fail under in-plane shear stress without the occurrence of fiber +breakage. This in-plane matrix failure mode is given by +𝑓11 = ( +𝜏𝑎𝑏 +𝑆𝑎𝑏 +) +− 1 = 0 +where 𝑆𝑎𝑏 is the layer shear strength due to matrix shear failure. +Another failure mode, which is due to the quadratic interaction between the thickness +stresses, is expected to be mainly a matrix failure. This through the thickness matrix +failure criterion is +𝑓12 = 𝑆2 {( +⟨𝜎𝑐⟩ +𝑆𝑐𝑇 +) +2 ++ ( +𝜏𝑏𝑐 +𝑆𝑏𝑐 +) ++ ( +𝜏𝑐𝑎 +𝑆𝑐𝑎 +) +} − 1 = 0 +where 𝑆𝑐𝑇 is the through the thickness tensile strength, and 𝑆𝑏𝑐, and 𝑆𝑐𝑎 are the shear +strengths assumed to depend on the compressive normal stress 𝜎𝑐, i.e., +𝑆𝑐𝑎 +{ +𝑆𝑏𝑐 +} = { +(0) +𝑆𝑐𝑎 +(0)} + tan(𝜑)⟨−𝜎𝑐⟩ +𝑆𝑏𝑐 +When failure predicted by this criterion occurs within elements that are adjacent to the +ply interface, the failure plane is expected to be parallel to the layering planes, and, +thus, can be referred to as the delamination mode. Note that a scale factor S is +introduced to provide better correlation of delamination area with experiments. The +scale factor S can be determined by fitting the analytical prediction to experimental data +for the delamination area. +Similar to the unidirectional model, when fiber tensile/shear failure is predicted in a +layer by f6 or f7, the load carrying capacity of that layer in the associated direction is +completely eliminated. For compressive fiber failure due to by f8 or f9, the layer is +assumed to carry a residual axial load in the failed direction, while the load carrying +capacity transverse to the failed direction is assumed unchanged. When the +compressive axial stress in a layer reaches the compressive axial strength 𝑆𝑎𝐶 or 𝑆𝑏𝐶, the +axial layer stress is assumed to be reduced to the residual strength 𝑆𝑎𝑅𝐶 or 𝑆𝑏𝑅𝐶 where +𝑆𝑎𝑅𝐶 = SFFC × 𝑆𝑎𝐶 and 𝑆𝑏𝑅𝐶 = SFFC × 𝑆𝑏𝐶. The axial stress is assumed to remain +constant, i.e., 𝜎𝑎 = −𝑆𝑎𝐶𝑅 or 𝜎𝑏 = −𝑆𝑏𝐶𝑅, for continuous compressive loading, while +the subsequent unloading curve follows a reduced axial modulus. When the fiber crush +failure is occurred, the material is assumed to behave elastically for compressive +pressure, p > 0, and to carry no load for tensile pressure, p < 0. +When the in-plane matrix shear failure is predicted by f11 the axial load carrying +capacity within a failed element is assumed unchanged, while the in-plane shear stress +is assumed to be reduced to zero. +For through the thickness matrix (delamination) failure given by equations f12, the in- +plane load carrying capacity within the element is assumed to be elastic, while the +(0), are set to zero. For tensile mode, +(0) and 𝑆𝑏𝑐 +strength values for the tensile mode, 𝑆𝑐𝑎 +𝜎𝑐 > 0, the through the thickness stress components are reduced to zero. For +compressive mode, 𝜎𝑐 < 0, 𝜎𝑐 is assumed to be elastic, while 𝜏𝑏𝑐 and 𝜏𝑐𝑎 ‘slide’ on the +fracture strength surface as in an ideal plastic material, and the unloading path follows +reduced shear moduli to the zero shear stress and strain state. +The effect of strain-rate on the layer strength values of the fiber failure modes is +modeled by the strain-rate dependent functions for the strength values {𝑆𝑅𝑇} as +{𝑆𝑅𝑇 } = {𝑆0 } ( 1 + 𝐶rate1 ln +̇} +{𝜀̅ +𝜀̇0 +) +{𝑆𝑅𝑇} = +⎧𝑆𝑎𝑇 +⎫ +} +{ +} +𝑆𝑎𝐶 +{ +} +{ +} +{ +𝑆𝑏𝑇 +⎬ +⎨ +𝑆𝑏𝐶 +} +{ +} +{ +𝑆𝐹𝐶 +} +{ +} +{ +𝑆𝐹𝑆 ⎭ +⎩ +, +{𝜀̅ +̇} = +⎧ +{{{{{ +{{{{{ +⎨ +⎩ +∣𝜀̇𝑎∣ +∣𝜀̇𝑎∣ +∣𝜀̇𝑏∣ +∣𝜀̇𝑏∣ +∣𝜀̇𝑐∣ +2 ) +2 + 𝜀̇𝑏𝑐 +(𝜀̇𝑐𝑎 +1/2 +⎫ +}}}}} +}}}}} +⎬ +⎭ +where Crate is the strain-rate constants, and {𝑆0 }are the strength values of {𝑆𝑅𝑇 } at the +reference strain-rate 𝜀̇0. +Damage model: +The damage model is a generalization of the layer failure model of Material 161 by +adopting the MLT damage mechanics approach, Matzenmiller et al. [1995], for +characterizing the softening behavior after damage initiation. Complete model +description is given in Yen [2002]. The damage functions, which are expressed in terms +of ply level engineering strains, are converted from the above failure criteria of fiber +and matrix failure modes by neglecting the Poisson’s effect. Elastic moduli reduction is +expressed in terms of the associated damage parameters 𝜛𝑖: +′ = (1 − 𝜛𝑖)𝐸𝑖 +𝐸𝑖 +𝜛𝑖 = 1 − exp (− +𝑚𝑖 +𝑟𝑖 +𝑚𝑖 +) , 𝑟𝑖 ≥ 0, 𝑖 = 1, . . . ,6, +′ are the reduced elastic moduli, 𝑟𝑖 are the +where 𝐸𝑖 are the initial elastic moduli, 𝐸𝑖 +damage thresholds computed from the associated damage functions for fiber damage, +matrix damage and delamination, and mi are material damage parameters, which are +currently assumed to be independent of strain-rate. The damage function is formulated +to account for the overall nonlinear elastic response of a lamina including the initial +‘hardening’ and the subsequent softening beyond the ultimate strengths. +In the damage model (material 162), the effect of strain-rate on the nonlinear stress- +strain response of a composite layer is modeled by the strain-rate dependent functions +for the elastic moduli {𝐸𝑅𝑇 } as +{𝐸𝑅𝑇 } = {𝐸0 } (1 + {𝐶rate} ln +̇} +{𝜀̅ +) +𝜀̇0 +{𝐸𝑅𝑇 } = +⎧ 𝐸𝑎 +⎫ +}} +{{ +𝐸𝑏 +}} +{{ +𝐸𝑐 +⎬ +⎨ +𝐺𝑎𝑏 +}} +{{ +𝐺𝑏𝑐 +}} +{{ +𝐺𝑐𝑎⎭ +⎩ +{𝜀̅ +̇} = +⎧ ∣𝜀̇𝑎∣ +⎫ +} +{ +} +{ +∣𝜀̇𝑏∣ +} +{ +} +{ +∣𝜀̇𝑐∣ +⎬ +⎨ +∣𝜀̇𝑎𝑏∣ +} +{ +} +{ +∣𝜀̇𝑏𝑐∣ +} +{ +} +{ +∣𝜀̇𝑐𝑎∣⎭ +⎩ +{𝐶rate} = +⎧𝐶rate2 +⎫ +} +{ +} +{ +𝐶rate2 +} +{ +} +{ +𝐶rate4 +⎬ +⎨ +𝐶rate3 +} +{ +} +{ +𝐶rate3 +} +{ +} +{ +𝐶rate3⎭ +⎩ +where {𝐶rate} are the strain-rate constants. {𝐸0 } are the modulus values of {𝐸𝑅𝑇 } at the +reference strain-rate 𝜀̇0. +Element Erosion: +A failed element is eroded in any of three different ways: +1. +2. +3. +If fiber tensile failure in a unidirectional layer is predicted in the element and +the axial tensile strain is greater than E_LIMT. For a fabric layer, both in-plane +directions are failed and exceed E_LIMT. +If compressive relative volume in a failed element is smaller than ECRSH. +If tensile relative volume in a failed element is greater than EEXPN. +Damage History Parameters: +Information about the damage history variables for the associated failure modes can be +plotted in LS-PrePost. These additional history variables are tabulated below: +History +Variable +Description +Value +LS-PrePost +History Variable +1. efa(I) +Fiber mode in a +2. efb(I) +Fiber mode in b +0-elastic +3. efp(I) +Fiber crush mode +4. em(I) +5. ed(I) +Perpendicular matrix +mode +Parallel matrix/ +delamination mode +6. delm(I) +delamination mode +≥1-failed +7 +8 +9 +10 +11 +12 +*MAT_MODIFIED_CRUSHABLE_FOAM +This is Material Type 163 which is dedicated to modeling crushable foam with optional +damping, tension cutoff, and strain rate effects. Unloading is fully elastic. Tension is +treated as elastic-perfectly-plastic at the tension cut-off value. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +TID +6 +7 +8 +TSC +DAMP +NCYCLE +F +F +F +F +Default +none +none +none +none +none +0.0 +0.10 +12. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SRCLMT +SFLAG +Type +F +Default +1.E+20 +I +0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +TID +TSC +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus +Poisson’s ratio +Table ID defining yield stress versus volumetric strain, γ, at +different strain rates. +Tensile stress cutoff. A nonzero, positive value is strongly +recommended for realistic behavior. +DAMP +Rate sensitivity via damping coefficient (.05 < recommended +value<.50). +> > +1-V +Figure M163-1. Rate effects are defined by a family of curves giving yield +stress versus volumetric strain where V is the relative volume. + VARIABLE +DESCRIPTION +NCYCLE +Number of cycles to determine the average volumetric strain rate. +SRCLMT +Strain rate change limit. +SFLAG +The strain rate in the table may be the true strain rate (SFLAG = 0) +or the engineering strain rate (SFLAG = 1). +Remarks: +The volumetric strain is defined in terms of the relative volume, V, as: +𝛾 = 1 − V +The relative volume is defined as the ratio of the current to the initial volume. In place +of the effective plastic strain in the D3PLOT database, the integrated volumetric strain is +output. +This material is an extension of material 63, *MAT_CRUSHABLE_FOAM. It allows the +yield stress to be a function of both volumetric strain rate and volumetric strain. Rate +effects are accounted for by defining a table of curves using *DEFINE_TABLE. Each +curve defines the yield stress versus volumetric strain for a different strain rate. The +yield stress is obtained by interpolating between the two curves that bound the strain +rate. +To prevent high frequency oscillations in the strain rate from causing similar high +frequency oscillations in the yield stress, a modified volumetric strain rate is used when +interpolating to obtain the yield stress. The modified strain rate is obtained as follows. +If NYCLE is > 1, then the modified strain rate is obtained by a time average of the actual +strain rate over NCYCLE solution cycles. For SRCLMT > 0, the modified strain rate is +capped so that during each cycle, the modified strain rate is not permitted to change +more than SRCLMT multiplied by the solution time step. +*MAT_BRAIN_LINEAR_VISCOELASTIC +This is Material Type 164. This material is a Kelvin-Maxwell model for modeling brain +tissue, which is valid for solid elements only. See Remarks below. + Card 1 +1 +Variable +MID +2 +RO +3 +BULK +Type +A8 +F +F +4 +G0 +F +5 +GI +F +6 +DC +F +7 +FO +F +8 +SO +F +Default +none +none +none +none +none +0.0 +0.0 +0.0 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +BULK +Bulk modulus (elastic) +G0 +GI +DC +FO +Short-time shear modulus, G0 +Long-time (infinite) shear modulus, G∞ +Maxwell decay constant, β[FO = 0.0] or +Kelvin relaxation constant, τ [FO = 1.0] +Formulation option: +EQ.0.0: Maxwell, +EQ.1.0: Kelvin. +VARIABLE +SO +DESCRIPTION +Strain (logarithmic) output option to control what is written as +component 7 to the d3plot database. (LS-PrePost always blindly +labels this component as effective plastic strain.) The maximum +values are updated for each element each time step: +EQ.0.0: maximum principal strain that occurs during the +calculation, +EQ.1.0: maximum magnitude of the principal strain values that +occurs during the calculation, +EQ.2.0: maximum effective strain that occurs during the +calculation. +Remarks: +The shear relaxation behavior is described for the Maxwell model by: +A Jaumann rate formulation is used +𝐺(𝑡) = 𝐺 + (𝐺0 − 𝐺∞)𝑒−𝛽𝑡 +𝛻 +𝑖𝑗 = 2 ∫ 𝐺(𝑡 − 𝜏)𝐷𝑖𝑗 +′ (𝜏)𝑑𝑡 +∇ +𝑖𝑗, and the strain rate Dij . +where the prime denotes the deviatoric part of the stress rate, 𝜎 +For the Kelvin model the stress evolution equation is defined as: +𝑠 ̇𝑖𝑗 + +𝑠𝑖𝑗 = (1 + 𝛿𝑖𝑗)𝐺0𝑒 ̇𝑖𝑗 + (1 + 𝛿𝑖𝑗) +𝐺∞ +𝑒 ̇𝑖𝑗 +The strain data as written to the d3plot database may be used to predict damage, see +[Bandak 1991]. +*MAT_PLASTIC_NONLINEAR_KINEMATIC +This is Material Type 165. This relatively simple model, based on a material model by +Lemaitre and Chaboche [1990], is suited to model nonlinear kinematic hardening +plasticity. The model accounts for the nonlinear Bauschinger effect, cyclic hardening, +and ratcheting. Huang [2006] programmed this model and provided it as a user +subroutine. It is a very cost effective model and is available shell and solid elements. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +SIGY +F +6 +H +F +7 +C +F +8 +GAMMA +F +Default +none +none +none +none +none +0.0 +0.0 +0.0 +2 +3 +4 +5 +6 +7 +8 + Card 2 +Variable +1 +FS +Type +F +Default +1.E+16 + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +SIGY +Initial yield stress, 𝜎𝑦0. +H +C +Isotropic plastic hardening modulus +Kinematic hardening modulus +VARIABLE +DESCRIPTION +GAMMA +Kinematic hardening parameter, 𝛾. +FS +Failure strain for eroding elements. +Remarks: +If the isotropic hardening modulus, H, is nonzero, the size of the surface increases as +function of the equivalent plastic strain,𝜀𝑝: +𝜎𝑦 = 𝜎𝑦0 + 𝐻𝜀𝑝 +The rate of evolution of the kinematic component is a function of the plastic strain rate: +𝛼̇ = [𝐶𝑛 − 𝛾𝛼]𝜀̇𝑝 +where, n, is the flow direction. The term, 𝛾𝛼𝜀̇𝑝, introduces the nonlinearity into the +evolution law, which becomes linear if the parameter, 𝛾, is set to zero. +*MAT_PLASTIC_NONLINEAR_KINEMATIC_B +This is Material Type 165B. This material model is implemented to model the cyclic +fatigue behavior. This model applies to both shell and solid elements. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +RE +F +6 +B +F +7 +Q +F +8 +C1 +F +Default +none +none +none +none +none +none +none +none + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable GAMMA1 +C2 +GAMMA2 +C3 +GAMMA3 +Type +F +F +F +F +F +Default +none +none +none +none +none + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +E +PR +RE +B +Q +Mass density. +Young’s Modulus +Poisson’s ratio +Yield stress, see Remarks. +Material parameter, see Remarks. +Material parameter, see Remarks. +VARIABLE +DESCRIPTION +Material parameters, see Remarks. +C1, +GAMMA1, +C2, +GAMMA2, +C3, +GAMMA3 +A model of elastoplatic cyclic hardening: +This material model is based on a 2013 paper by S. Plessis which modeled a double- +notched specimen with Herbland (2009) material model. The elstoplastic stress tensor is +given by: +𝜎 = 𝜎𝑀 − 𝐿: ε𝑝 +where, 𝜎𝑀 is elastic stress, ε𝑝 is the plastic strain tensor. In a one-dimensional problem, +the above equation becomes: +where, 𝐿′ is a parameter identified with FEM on a monotonic loading. +𝜎 = 𝜎𝑀 − 𝐿′ε𝑝 +In the elasticity domain: +𝑓 = 𝐽2(𝜎 − 𝑋𝑇) − 𝑅𝑒 − 𝑅 ≤ 0 +where 𝐽2 is the second stress invariant, 𝜎 is the stress tension, 𝑅 is the isotropic +hardening variable, 𝑅𝑒 (variable RE) is the yield stress. +Evolution law of the isotropic hardening variable R: +𝑅̇ = 𝑏 𝑋(𝑄 − 𝑅)𝑝̇ +where 𝑏 (variable B) and 𝑄 (variable Q) are two material parameters, 𝑝̇ is the plastic +strain rate defined by: +𝑝̇ = √ +𝜖 ̇𝑝: 𝜖 ̇𝑝 +with 𝜖 ̇𝑝 the plastic strain tensor. +Evolution law of the variable of kinematic hardening: +with, +𝑋𝑇̇ + = ∑ 𝑋𝚤̇ +𝑋𝚤̇ = +𝐶𝑖𝜖 ̇𝑝 − 𝛾𝑖𝑋𝑖𝑝̇ +where 𝑋𝑇̇ is the kinematic hardening tensor, and is the sum of three tensors 𝑋𝚤̇ (𝑖 = 1~3), +each dependent on the one set of material coefficients 𝐶𝑖 (variables C1, C2, C3) and +𝛾𝑖(variables GAMMA1, GAMMA2, GAMMA3). +Revision information: +This material model is available starting in Revision 102594. +*MAT_MOMENT_CURVATURE_BEAM +This is Material Type 166. This material is for performing nonlinear elastic or multi- +linear plastic analysis of Belytschko-Schwer beams with user-defined axial force-strain, +moment curvature and torque-twist rate curves. If strain, curvature or twist rate is +located outside the curves, use extrapolation to determine the corresponding rigidity. +For multi-linear plastic analysis, the user-defined curves are used as yield surfaces. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +5 +6 +7 +8 +ELAF +EPFLG +CTA +CTB +CTT +F +F +F +F +F +Default +none +none +none +none +0.0 +0.0 +0.0 +0.0 + Card 2 +Variable +1 +N1 +Type +F +2 +N2 +F +Default +none +none +3 +N3 +F +0.0 / +none +4 +N4 +F +5 +N5 +F +6 +N6 +F +7 +N7 +F +8 +N8 +F +0.0 +0.0 +0.0 +0.0 +0.0 + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCMS1 +LCMS2 +LCMS3 +LCMS4 +LCMS5 +LCMS6 +LCMS7 +LCMS8 +Type +F +F +F +F +F +F +F +F +Default +none +none +0.0 / +none +0.0 +0.0 +0.0 +0.0 +0.0 +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCMT1 +LCMT2 +LCMT3 +LCMT4 +LCMT5 +LCMT6 +LCMT7 +LCMT8 +Type +F +F +F +F +F +F +F +F +Default +none +none +0.0 / +none +0.0 +0.0 +0.0 +0.0 +0.0 + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCT1 +LCT2 +LCT3 +LCT4 +LCT5 +LCT6 +LCT7 +LCT8 +Type +F +F +F +F +F +F +F +F +Default +none +none +0.0 / +none +0.0 +0.0 +0.0 +0.0 +0.0 +Multilinear Plastic Analysis Card. Additional card for EPFLG = 1. + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CFA +CFB +CFT +HRULE +REPS +RBETA +RCAPAY +RCAPAZ +Type +F +F +F +F +F +F +F +F +Default +1.0 +1.0 +1.0 +0.0 +1.0E+20 1.0E+20 1.0E+20 1.0E+20 + VARIABLE +DESCRIPTION +MID +RO +E +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus. This variable controls the time step size and +must be chosen carefully. Increasing the value of E will decrease +the time step size. +VARIABLE +DESCRIPTION +ELAF +Load curve ID for the axial force-strain curve +EPFLG +Function flag +EQ.0.0: nonlinear elastic analysis +EQ.1.0: multi-linear plastic analysis +CTA, CTB, +CTT +Type of axial force-strain, moment-curvature, and torque-twist +rate curves +EQ.0.0: curve is symmetric +EQ.1.0: curve is asymmetric +For symmetric curves, all data point must be in the first quadrant +and at least three data points need to be given, starting from the +origin, ensued by the yield point. +For asymmetric curves, at least five data points are needed and +exactly one point must be at the origin. The two points on both +sides of the origin record the positive and negative yield points. +The last data point(s) has no physical meaning: it serves only as a +control point for inter or extrapolation. +The curves are input by the user and treated in LS-DYNA as a +linearly piecewise function. The curves must be monotonically +increasing, while the slopes must be monotonically decreasing +Axial forces at which moment-curvature curves are given. The +axial forces must be ordered monotonically increasing. At least +two axial forces must be defined if the curves are symmetric. At +least three axial forces must be defined if the curves are +asymmetric. +Load curve IDs for the moment-curvature curves about axis S +under corresponding axial forces. +Load curve IDs for the moment-curvature curves about axis T +under corresponding axial forces. +Load curve +corresponding axial forces. +IDs +for +the +torque-twist rate curves under +For multi-linear plastic analysis only. Ratio of axial, bending and +torsional elastic rigidities to their initial values, no less than 1.0 in +value. +N1 - N8 +LCMS1 - +LCMS8 +LCMT1 - +LCMT8 +LCT1 - LCT8 +CFA, CFB, +CFT +*MAT_MOMENT_CURVATURE_BEAM +DESCRIPTION +HRULE +Hardening rule, for multi-linear plastic analysis only. +EQ.0.0: +isotropic hardening +GT.0.0.AND.LT.1.0: mixed hardening +EQ.1.0: +kinematic hardening +REPS +Rupture effective plastic axial strain +RBETA +Rupture effective plastic twist rate +RCAPAY +Rupture effective plastic curvature about axis S +RCAPAZ +Rupture effective plastic curvature about axis T +*MAT_167 +This is Material Type 167. This is a constitute model for finite plastic deformities in +which the material’s strength is defined by McCormick’s constitutive relation for +materials exhibiting negative steady-state Strain Rate Sensitivity (SRS). McCormick +[1988] and Zhang, McCormick and Estrin [2001]. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F + Card 2 +Variable +1 +Q1 +Type +F + Card 3 +Variable +Type +1 +S +F +2 +C1 +F +2 +H +F +3 +E +F +3 +Q2 +F +3 +4 +PR +F +4 +C2 +F +4 +5 +6 +7 +8 +SIGY +F +5 +6 +7 +8 +5 +6 +7 +8 +OMEGA +TD +ALPHA +EPS0 +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +SIGY +Initial yield stress +Q1 +C1 +Isotropic hardening parameter, 𝑄1 +Isotropic hardening parameter, 𝐶1 +VARIABLE +Q2 +C2 +S +H +DESCRIPTION +Isotropic hardening parameter, 𝑄2 +Isotropic hardening parameter, 𝐶2 +Dynamic strain aging parameter, 𝑆 +Dynamic strain aging parameter, 𝐻 +OMEGA +Dynamic strain aging parameter, Ω +TD +Dynamic strain aging parameter, 𝑡𝑑 +ALPHA +Dynamic strain aging parameter, 𝛼 +EPS0 +Reference strain rate, 𝜀̇0 +Remarks: +The uniaxial stress-strain curve is given in the following form: +𝜎(𝜀𝑝, 𝜀̇𝑝) = 𝜎𝑌(𝑡𝑎) + 𝑅(𝜀𝑝) + 𝜎𝑣(𝜀̇𝑝) +Viscous stress 𝜎𝑣 is given by +𝜎𝑣(𝜀̇𝑝) = S × ln (1 + +𝜀̇𝑝 +𝜀̇𝑜 +) +where 𝑆 represents the instantaneous strain rate sensitivity and 𝜀̇𝑜 is a reference strain +rate. +In the McCormick model the yield strength including the contribution from dynamic +strain again (DSA) is defined as +𝜎𝑌(𝑡𝑎) = 𝜎𝑜 + S × H × [1 − exp {− ( +) +𝑡𝑎 +𝑡𝑑 +}] +where 𝜎𝑜 is the yield strength for vanishing average waiting time 𝑡𝑎, and 𝐻, 𝛼, and 𝑡𝑑 are +material constants linked to dynamic strain aging. +The average waiting time is defined by the evolution equation +𝑡 ̇𝑎 = 1 − +𝑡𝑎 +𝑡𝑎,𝑠𝑠 +where the quasi-steady state waiting time 𝑡𝑎,𝑠𝑠 is given as +𝑡𝑎,𝑠𝑠 = +𝜀̇𝑝. +The strain hardening function 𝑅 is defined by the extended Voce Law +𝑅(𝜀𝑝) = 𝑄1[1 − exp(−𝐶1𝜀𝑝)] + 𝑄2[1 − exp(−𝐶2𝜀𝑝)]. +*MAT_POLYMER +This is material type 168. This model is implemented for brick elements. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +Variable +TEMP +Type +F +2 +RO +F +2 +K +F +3 +E +F +3 +CR +F +4 +5 +6 +PR +GAMMA0 +DG +F +6 +F +4 +N +F +F +5 +C +F + VARIABLE +DESCRIPTION +7 +SC +F +7 +8 +ST +F +8 +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass Density. +Young’s modulus, 𝐸. +Poisson’s ratio, 𝜈. +GAMMA0 +Pre-exponential factor, 𝛾̇0𝐴. +DG +SC +ST +Energy barrier to flow, Δ𝐺. +Shear resistance in compression, 𝑆𝑐. +Shear resistance in tension, 𝑆𝑡. +TEMP +Absolute temperature, 𝜃. +K +CR +N +C +Boltzmann constant, 𝑘. +Product, 𝐶𝑟 = 𝑛𝑘𝜃. +Number of ‘rigid links’ between entanglements, 𝑁. +Relaxation factor, 𝐶. +*MAT_168 +The polymer is assumed to have two basic resistances to deformation: +Elastic stiffness +(Hooke's law) +Plastic flow +(Argon's model) +A B +Network +stiffness +(Arruda- +Boyce model) +Total +A (Inter-molecular) +B (Network) +True strain +Figure M168-1. Stress decomposition in inter-molecular and network +contributions. +1. An inter-molecular barrier to deformation related to relative movement +between molecules. +2. An evolving anisotropic resistance related to straightening of the molecule +chains. +The model which is implemented and presented in this paper is mainly based on the +framework suggested by Boyce et al. [2000]. Going back to the original work by +Haward and Thackray [1968], they considered the uniaxial case only. The extension to +a full 3D formulation was proposed by Boyce et al. [1988]. Moreover, Boyce and co- +workers have during a period of 20 years changed or further developed the parts of the +original model. Haward and Thackray [1968] used an Eyring model to represent the +dashpot in Fig. M168-1, while Boyce et al. [2000] employed the double-kink model of +Argon [1973] instead. Part B of the model, describing the resistance associated with +straightening of the molecules, contained originally a one-dimensional Langevin spring +[Haward and Thackray, 1968], which was generalized to 3D with the eight-chain model +by Arruda and Boyce [1993]. +The main structure of the model presented by Boyce et al. [2000] is kept for this model. +Recognizing the large elastic deformations occurring for polymers, a formulation based +on a Neo-Hookean material is here selected for describing the spring in resistance A in +Figure M168-1. +Referring to Figure M168-1, it is assumed that the deformation gradient tensor is the +same for the two resistances (Part A and B) +while the Cauchy stress tensor for the system is assumed to be the sum of the Cauchy +stress tensors for the two parts +𝐅 = 𝐅𝐴 = 𝐅𝐵 +σ = σ𝐴 + σ𝐵. +Part A: Inter-molecular resistance: +𝑝 , where it is +The deformation is decomposed into elastic and plastic parts, 𝐅𝐴 = 𝐅𝐴 +𝑝 is invariant to rigid +assumed that the intermediate configuration Ω̅̅̅̅̅̅𝐴 defined by 𝐅𝐴 +body rotations of the current configuration. The velocity gradient in the current +configuration Ω is defined by +𝑒 ⋅ 𝐅𝐴 +Owing to the decomposition, 𝐅𝐴 = 𝐅𝐴 +and spin tensors are defined by +𝐋𝐴 = 𝐅̇𝐴 ⋅ 𝐅𝐴 +𝑒 ⋅ 𝐅𝐴 +𝑝 +𝑒 + 𝐋𝐴 +−1 = 𝐋𝐴 +𝑝 , the elastic and plastic rate-of-deformation +𝑒 + 𝐖𝐴 +𝑝 + 𝐖𝐴 +𝑒 = 𝐅̇ +𝑝 = 𝐅𝐴 +𝑒 ⋅ (𝐅𝐴 +𝑒 ⋅ 𝐅̇ +𝑒 )−1 +𝑝 ⋅ (𝐅𝐴 +𝑝 )−1 ⋅ (𝐅𝐴 +𝑒 )−1 = 𝐅𝐴 +𝑒 ⋅ 𝐋̅ +𝑝 ⋅ (𝐅𝐴 +𝑒 )−1 +𝑒 = 𝐃𝐴 +𝐋𝐴 +𝑝 = 𝐃𝐴 +𝐋𝐴 +𝑝 ⋅ (𝐅𝐴 +𝑝 = 𝐅̇ +𝑝 )−1. The Neo-Hookean material represents an extension of Hooke's +where 𝐋̅ +law to large elastic deformations and may be chosen for the elastic part of the +deformation when the elastic behavior is assumed to be isotropic. +τ𝐴 = 𝜆0ln𝐽𝐴 +𝑒 𝐈 + 𝜇0(𝐁𝐴 +𝑒 − 𝐈) +𝑒 = 𝐽𝐴 is the +where τ𝐴 = 𝐽𝐴σ𝐴 is the Kirchhoff stress tensor of Part A and 𝐽𝐴 +Jacobian determinant. The elastic left Cauchy-Green deformation tensor is given by +𝑒 = 𝐅𝐴 +𝐁𝐴 +𝑒 = √det𝐁𝐴 +𝑒 ⋅ 𝐅𝐴 +𝑒 𝑇. +The flow rule is defined by +where +𝑝 = 𝛾̇𝐴 +𝐋𝐴 +𝑝 𝐍𝐴 +𝐍𝐴 = +√2 𝜏𝐴 +dev, +τ𝐴 +𝜏𝐴 = √ +dev) +tr(τ𝐴 +𝑑𝑒𝑣 is the stress deviator. The rate of flow is taken to be a thermally activated +and τ𝐴 +process +𝑝 = 𝛾̇0𝐴exp [− +𝛾̇𝐴 +Δ𝐺(1 − 𝜏𝐴/𝑠) +𝑘𝜃 +] +where 𝛾̇0𝐴 is a pre-exponential factor, Δ𝐺 is the energy barrier to flow, 𝑠 is the shear +resistance, 𝑘 is the Boltzmann constant and 𝜃 is the absolute temperature. The shear +resistance 𝑠 is assumed to depend on the stress triaxiality 𝜎 ∗, +𝑠 = 𝑠(𝜎 ∗), 𝜎 ∗ = +tr σ𝐴 +3√3𝜏𝐴 +The exact dependence is given by a user-defined load curve, which is linear between the +shear resistances in compression and tension. These resistances are denoted sc and st, +respectively. +Part B: Network resistance: +The network resistance is assumed to be nonlinear elastic with deformation gradient +𝑁, i.e. any viscoplastic deformation of the network is neglected. The stress- +𝐅𝐵 = 𝐅𝐵 +stretch relation is defined by +τ𝐵 = +𝑛𝑘𝜃 +√𝑁 +𝜆̅̅̅̅𝑁 +ℒ −1 +⎜⎛ 𝜆̅̅̅̅𝑁 +√𝑁⎠ +⎝ +⎟⎞ (𝐁̅̅̅̅ +𝑁 − 𝜆̅̅̅̅ +2 𝐈) +where τ𝐵 = 𝐽𝐵σ𝐵 is the Kirchhoff stress for Part B, 𝑛 is the chain density and 𝑁 the +number of ‘rigid links’ between entanglements. In accordance with Boyce et. al [2000], +the product, 𝑛𝑘𝜃 is denoted 𝐶𝑅 herein. Moreover, ℒ −1 is the inverse Langevin function, +ℒ(𝛽) = coth𝛽 − 1 𝛽⁄ , and further +𝐁̅̅̅̅ +𝑁 = 𝐅̅̅̅̅ +𝑁 ⋅ 𝐅̅̅̅̅ +𝑁 𝑇 +, 𝐅̅̅̅̅ +𝑁 = 𝐽𝐵 +−1/3 𝐅𝐵 +𝑁, 𝐽𝐵 = det𝐅𝐵 +𝑁, 𝜆̅̅̅̅𝑁 = [ +tr 𝐁̅̅̅̅ +𝑁] +The flow rule defining the rate of molecular relaxation reads +𝐹 = 𝛾̇𝐵 +𝐋𝐵 +𝐹𝐍𝐵 +where +𝐍𝐵 = +√2 𝜏𝐵 +dev, +τ𝐵 +𝜏𝐵 = √ +dev: τ𝐵 +τ𝐵 +dev +The rate of relaxation is taken equal to +where +𝐹 = 𝐶 ( +𝛾̇𝐵 +𝜆̅̅̅̅𝐹 − 1 +) 𝜏𝐵 +𝜆̅̅̅̅𝐹 = [ +tr(𝐅𝐵 +𝐹} +𝐹{𝐅𝐵 +)] +The model has been implemented into LS-DYNA using a semi-implicit stress-update +scheme [Moran et. al 1990], and is available for the explicit solver only. +*MAT_169 +This is Material Type 169. This material model was written for adhesive bonding in +aluminum structures. The plasticity model is not volume-conserving, and hence avoids +the spuriously high tensile stresses that can develop if adhesive is modeled using +traditional elasto-plastic material models. It is available only for solid elements of +formulations 1, 2 and 15. The smallest dimension of the element is assumed to be the +through-thickness dimension of the bond, unless THKDIR = 1. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +5 +6 +7 +8 +PR +TENMAX +GCTEN +SHRMAX +GCSHR +F +F +F +F +F +Default +none +none +none +none +1020 +1020 +1020 +1020 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PWRT +PWRS +SHRP +SHT_SL +EDOT0 +EDOT2 +THKDIR +EXTRA +Type +F +F +F +F +F +F +F +F +Default +2.0 +2.0 +0.0 +0.0 +1.0 +0.0 +0.0 +0.0 +Additional card for Extra = 1 or 3. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TMAXE +GCTE +SMAXE +GCSE +PWRTE +PWRSE +Type +F +F +F +F +F +F +Default +1020 +1020 +1020 +1020 +2.0 +2.0 +*MAT_ARUP_ADHESIVE + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FACET +FACCT +FACES +FACCS +SOFTT +SOFTS +Type +F +F +F +F +F +F +Default +1.0 +1.0 +1.0 +1.0 +1.0 +1.0 +Dynamic Strain Rate Card. Additional card for EDOT2 ≠ 0. + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SDFAC +SGFAC +SDEFAC +SGEFAC +Type +F +F +F +F +Default +1.0 +1.0 +1.0 +1.0 +Bond Thickness Card. Additional card for Extra = 2 or 3. + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +BTHK +OUTFAIL +FSIP +Type +F +F +F +Default +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +VARIABLE +DESCRIPTION +TENMAX +Maximum through-thickness tensile stress +GT.0.0: constant value +LT.0.0: |TENMAX| is ID of a *DEFINE_FUNCTION +GCTEN +Energy per unit area to fail the bond in tension +GT.0.0: constant value +LT.0.0: |GCTEN| is ID of a *DEFINE_FUNCTION +SHRMAX +Maximum through-thickness shear stress +GT.0.0: constant value +LT.0.0: |SHRMAX| is ID of a *DEFINE_FUNCTION +GCSHR +Energy per unit area to fail the bond in shear +GT.0.0: constant value +LT.0.0: |GCSHR| is ID of a *DEFINE_FUNCTION +Power law term for tension +Power law term for shear +Shear plateau ratio (Optional) +GT.0.0: constant value +LT.0.0: |SHRP| +Remarks) +is +ID of a *DEFINE_FUNCTION + of yield surface at zero tension +EDOT0 +Strain rate at which the “static” properties apply +EDOT2 +Strain rate at which the “dynamic” properties apply (Card 5) +THKDIR +Through-thickness direction flag +EQ.0.0: smallest element dimension (default) +EQ.1.0: direction from nodes 1-2-3-4 to nodes 5-6-7-8 +*MAT_ARUP_ADHESIVE +DESCRIPTION +EXTRA +Flag to input further data: +EQ.1.0: interfacial failure properties (cards 3 and 4) +EQ.2.0: bond thickness and more (card 6) +EQ.3.0: both of the above +TMAXE +Maximum tensile force per unit length on edges of joint +GCTE +Energy per unit length to fail the edge of the bond in tension +SMAXE +Maximum shear force per unit length on edges of joint +GCSE +Energy per unit length to fail the edge of the bond in shear +PWRTE +Power law term for tension +PWRSE +Power law term for shear +FACET +Stiffness scaling factor for edge elements – tension +FACCT +Stiffness scaling factor for interior elements – tension +FACES +Stiffness scaling factor for edge elements – shear +FACCS +Stiffness scaling factor for interior elements – shear +SOFTT +SOFTS +Factor by which the tensile strength is reduced when a neighbor +fails +Factor by which the shear strength is reduced when a neighbor +fails +SDFAC +Factor on TENMAX and SHRMAX at strain rate EDOT2 +GT.0.0: constant value +LT.0.0: |SDFAC| +Remarks) +is ID of a *DEFINE_FUNCTION +is ID of a *DEFINE_FUNCTION (see +SDEFAC +Factor on TMAXE and SMAXE at strain rate EDOT2 +VARIABLE +DESCRIPTION +SGEFAC +Factor on GCTE and GCSE at strain rate EDOT2 +BTHK +Bond thickness (overrides thickness from element dimensions) +LT.0.0: |BTHK| is bond thickness, but critical time step +remains unaffected. Helps to avoid very small time +steps, but it can affect stability. +OUTFAIL +Flag for additional output to messag file: Information about +damage +initiation time, failure function terms and forces. +EQ.0.0: off +EQ.1.0: on +FSIP +Effective in-plane strain at failure. +Remarks: +The through-thickness direction is identified from the smallest dimension of each +element by default (THKDIR = 0.0). It is expected that this dimension will be smaller +than in-plane dimensions (typically 1-2mm compared with 5-10mm). If this is not the +through-thickness direction via element numbering +case, one can set +(THKDIR = 1.0). Then the thickness direction is expected to point from lower face +(nodes 1-2-3-4) to upper face (nodes 5-6-7-8). For wedge elements these faces are the +two triangular faces (nodes 1-2-5) and (nodes 3-4-6). +the +The bond thickness is assumed to be the element size in the thickness direction. This +may be overridden using BTHK. In this case the behavior becomes independent of the +element thickness. The elastic stiffness is affected by BTHK, so it is necessary to set the +characteristic element length to a smaller value +new = √BTHK × 𝑙𝑒 +𝑙𝑒 +old. +This again affects the critical time step of the element, i.e. a small BTHK can decrease +the element time step significantly. +In-plane stresses are set to zero: it is assumed that the stiffness and strength of the +substrate is large compared with that of the adhesive, given the relative thicknesses. +If the substrate is modeled with shell elements, it is expected that these will lie at the +mid-surface of the substrate geometry. Therefore the solid elements representing the +adhesive will be thicker than the actual bond. If the elastic compliance of the bond is +significant, this can be corrected by increasing the elastic stiffness property E. +SHT_SL > 0 +SHT_SL = 0 +shear +stress +SHRMAX +direct +stress +TENMAX +Figure M169-1. Figure illustrating the yield surface. +The yield and failure surfaces are treated as a power-law combination of direct tension +and shear across the bond: +( +𝜎max +PWRT + + ( +) +𝜏max − SHT_ SL × 𝜎 +PWRS + = 1.0 +) +At yield SHT_SL is the slope of the yield surface at 𝜎 = 0. See Figure M169-1 +The stress-displacement curves for tension and shear are shown in Figure M169-2. In +both cases, GC is the area under the curve. The displacement to failure in tension is +given by +subject to a lower limit +𝑑ft = 2 ( +GCTEN +TENMAX +) , +𝑑ft, min = ( +2𝐿0 +𝐸′ ) TENMAX +where 𝐿0 is the initial element thickness (or BTHK if used) and +𝐸′ = +𝐸(1 − 𝜈) +(1 − 2𝜈)(1 + 𝜈) + . +If GCTEN is input such that 𝑑ft < 𝑑ft, min, LS-DYNA will automatically increase GCTEN +to make 𝑑ft = 𝑑ft, min. Therefore, GCTEN has a minimum value of +dp = SHRP × dfs +TENAMX +Area = GCten +Failure (dft) +SHRMAX +Area = GCshr +Failure (dfs) +Displacement +(Tension) +Displacement +(Shear) +Figure M169-2. Stress-Displacement Curves for Tension and Shear. +σMAX/TENMAX +SDFAC +1.0 +Log(plastic strain rate) +Log(EDOT0) +Log(EDOT2) +Figure M169-3. Figure illustrating rate effects. +Similarly, the minimum value for GCSHR is +GCTEN ≥ +𝐿0 +𝐸′ (TENMAX)2 +GCSHR ≥ +𝐿0 +(SHRMAX)2 +where 𝐺 is the elastic shear modulus. +Because of the algorithm used, yielding in tension across the bond does not require +strains in the plane of the bond – unlike the plasticity models, plastic flow is not treated +as volume-conserving. +The Plastic Strain output variable has a special meaning: +0 < PS < 1: PS is the maximum value of the yield function experienced +since time zero +1 < PS < 2: +the element has yielded and the strength is reducing towards +failure – yields at PS = 1, fails at PS = 2. +The damage cause by cohesive deformation (0 at first yield to 1 at failure) and by +interfacial deformation are stored in the first two extra history variables. These can be +plotted if NEIPH on *DATABASE_EXTENT_BINARY is 2 or more. By this means, the +reasons for failure may be assessed. +When the plastic strain rate rises above EDOT0, rate effects are assumed to scale with +the logarithm of the lastic strain rate, as in the example shown in Figure M169-3 for +cohesive tensile strength with dynamic factor SDFAC. The same form of relationship is +applied for the other dynamic factors. If EDOT0 is zero or blank, no rate effects are +applied. Rate effects are applied using the viscoplastic method. +Interfacial failure is assumed to arise from stress concentrations at the edges of the bond +– typically the strength of the bond becomes almost independent of bond length. This +type of failure is usually more brittle than cohesive failure. To simulate this, LS-DYNA +identifies the free edges of the bond (made up of element faces that are not shared by +other elements of material type *MAT_ARUP_ADHESIVE, excluding the faces that +bond to the substrate). Only these elements can fail initially. The neighbors of failed +elements can then develop free edges and fail in turn. +In real adhesive bonds, the stresses at the edges can be concentrated over very small +areas; in typical finite element models the elements are much too large to capture this. +Therefore the concentration of loads onto the edges of the bond is accomplished +artificially, by stiffening elements containing free edges (e.g. FACET, FACES > 1) and +reducing the stiffness of interior elements (e.g. FACCT, FACCS < 1). Interior elements +are allowed to yield at reduced loads (equivalent to TMAXE × FACET/FACCT and +SMAXE × FACES/FACCS) to prevent excessive stresses developing before the edge +elements have failed - but cannot be damaged until they become edge elements after the +failure of their neighbors. +Parameters TENMAX, GCTEN, SHRMAX, GCSHR, SHRP, SDFAC, and SGFAC can be +defined as negative values. +to +*DEFINE_FUNCTION ID’s. The arguments of those functions include several +properties of both connection partners if corresponding solid elements are in a tied +contact with shell elements. +the absolute values refer +that case, +In +These functions depend on: +(t1, t2) = thicknesses of both bond partners +(sy1, sy2) = initial yield stresses at plastic strain of 0.002 +(sm1, sm2) = maximum engineering yield stresses (necking points) +r = strain rate +a = element area +For TENMAX = -100 such a function could look like: +*DEFINE_FUNCTION + 100 + func(t1,t2,sy1,sy2,sm1,sm2,r,a)=0.5*(sy1+sy2) +Since material parameters have to be identified from both bond partners during +initialization, this feature is only available for a subset of material models at the +moment, namely no. 24, 120, 123, and 124. +*MAT_RESULTANT_ANISOTROPIC +This is Material Type 170. This model is available the Belytschko-Tsay and the C0 +triangular shell elements and is based on a resultant stress formulation. In-plane +behavior is treated separately from bending in order to model perforated materials such +as television shadow masks. The plastic behavior of each resultant is specified with a +load curve and is completely uncoupled from the other resultants. If other shell +formulations are specified, the formulation will be automatically switched to +Belytschko-Tsay. As implemented, this material model cannot be used with user +defined integration rules. +NOTE: This material does not support specification of a ma- +terial angle, 𝛽𝑖, for each through-thickness integra- +tion point of a shell. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +4 +5 +6 +7 +8 +3 +4 +5 +6 +7 +8 +Variable +E11P +E22P +V12P +V21P +G12P +G23P +G31P +Type +F + Card 3 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +8 +Variable +E11B +E22B +V12B +V21B +G12B +AOPT +Type +F +F +F +F +F +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LN11 +LN22 +LN12 +LQ1 +LQ2 +LM11 +LM22 +LM12 +Type +F + Card 5 +1 +Variable +Type + Card 6 +Variable +1 +V1 +Type +F +F +2 +2 +V2 +F +F +3 +3 +V3 +F +F +F +F +4 +A1 +F +4 +D1 +F +5 +A2 +F +5 +D2 +F +6 +A3 +F +6 +D3 +F +F +7 +F +8 +7 +8 +BETA +F + VARIABLE +DESCRIPTION +MID +RO +E11P +E22P +V12P +V11P +G12P +G23P +G31P +E11B +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +𝐸11𝑝, for in plane behavior. +𝐸22𝑝, for in plane behavior. +𝜈12𝑝, for in plane behavior. +𝜈11𝑝, for in plane behavior. +𝐺12𝑝, for in plane behavior. +𝐺23𝑝, for in plane behavior. +𝐺31𝑝, for in plane behavior. +𝐸11𝑏, for bending behavior. +VARIABLE +DESCRIPTION +E22B +V12B +V21B +G12B +AOPT +𝐸22𝑏, for bending behavior. +𝜈12𝑏, for bending behavior. +𝜈21𝑏, for bending behavior. +𝐺12𝑏, for bending behavior. +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the shell ele- +ment normal by the angle BETA. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector 𝐯 with the +element normal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +LN11 +LN22 +LN12 +LQ1 +LQ2 +LM11 +LM22 +LM12 +Yield curve ID for 𝑁11, the in-plane force resultant. +Yield curve ID for 𝑁22, the in-plane force resultant. +Yield curve ID for 𝑁12, the in-plane force resultant. +Yield curve ID for 𝑄1, the transverse shear resultant. +Yield curve ID for 𝑄2, the transverse shear resultant. +Yield curve ID for 𝑀11, the moment. +Yield curve ID for 𝑀22, the moment. +Yield curve ID for 𝑀12, the moment. +*MAT_RESULTANT_ANISOTROPIC +DESCRIPTION +A1, A2, A3 +(𝑎1, 𝑎2, 𝑎3), define components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +(𝑣1, 𝑣2, 𝑣3), define components of vector 𝐯 for AOPT = 3. +D1, D2, D3 +(𝑑1, 𝑑2, 𝑑3), define components of vector 𝐝 for AOPT = 2. +BETA +Material angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA. +Remarks: +The in-plane elastic matrix for in-plane, plane stress behavior is given by: +𝐂in plane = +𝑄11𝑝 𝑄12𝑝 0 0 0 +⎤ +𝑄12𝑝 𝑄22𝑝 0 0 0 +⎥ +⎥ + 0 0 𝑄44𝑝 0 0 +⎥ +⎥ + 0 0 0 𝑄55𝑝 0 +⎥ + 0 0 0 0 𝑄66𝑝⎦ +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +The terms 𝑄𝑖𝑗𝑝 are defined as: +𝑄11𝑝 = +𝑄22𝑝 = +𝑄12𝑝 = +𝐸11𝑝 +1 − 𝜈12𝑝𝜈21𝑝 +𝐸22𝑝 +1 − 𝜈12𝑝𝜈21𝑝 +𝜈12𝑝𝐸11𝑝 +1 − 𝜈12𝑝𝜈21𝑝 +𝑄44𝑝 = 𝐺12𝑝 +𝑄55𝑝 = 𝐺23𝑝 +𝑄66𝑝 = 𝐺31𝑝 +The elastic matrix for bending behavior is given by: +𝐂bending = +𝑄11𝑏 𝑄12𝑏 0 +⎤ +⎡ +𝑄12𝑏 𝑄22𝑏 0 +⎥ +⎢ + 0 0 𝑄44𝑏⎦ +⎣ +The terms 𝑄𝑖𝑗𝑝 are similarly defined. +Because this is a resultant formulation, no stresses are output to d3plot, and forces and +moments are reported to elout in place of stresses. +*MAT_STEEL_CONCENTRIC_BRACE +This is Material Type 171. It represents the cyclic buckling and tensile yielding behavior +of steel braces and is intended primarily for seismic analysis. Use only for beam +elements with ELFORM = 2 (Belytschko-Schwer beam). + Card 1 +1 +Variable +MID +2 +RO +3 +YM +Type +A8 +F +F +4 +PR +F +5 +6 +7 +8 +SIGY +LAMDA +FBUCK +FBUCK2 +F +F +F +F +Default +none +none +none +none +none +See +Remarks +See +Remarks +0.0 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CCBRF +BCUR +Type +F +F +Default +See +Remarks + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TS1 +TS2 +TS3 +TS4 +CS1 +CS2 +CS3 +CS4 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +F +F +F + = TS1 + = TS2 + = TS3 + = TS4 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +VARIABLE +DESCRIPTION +YM +PR +Young’s Modulus +Poisson’s Ratio +SIGY +Yield stress +LAMDA +Slenderness ratio (optional – see note) +FBUCK +Initial buckling load (optional – see note. If used, should be +positive) +FBUCK2 +Optional extra term in initial buckling load – see note +CCBRF +Reduction factor on initial buckling load for cyclic behavior +BCUR +Optional load curve giving compressive buckling load (y-axis) +versus compressive strain (x-axis - both positive) +TS1 - TS4 +Tensile axial strain thresholds 1 to 4 +CS1 - CS4 +Compressive axial strain thresholds 1 to 4 +Remarks: +The brace element is intended to represent the buckling, yielding and cyclic behavior of +steel elements such as tubes or I-sections that carry only axial loads. Empirical +relationships are used to determine the buckling and cyclic load-deflection behavior. A +single beam element should be used to represent each structural element. +The cyclic behavior is shown in the graph (compression shown as negative force and +displacement). +16 +17 +15 +12 +19 +14 +11,13 +10 +18 +Figure M171-1. +The initial buckling load (point 2) is: +𝐹𝑏 initial = FBUCK + +FBUCK2 +𝐿2 +where FBUCK, FBUCK2 are input parameters and L is the length of the beam element. +If neither FBUCK nor FBUCK2 are defined, the default is that the initial buckling load is +where A is the cross sectional area. The buckling curve (shown dashed) has the form: +SIGY × A, +𝐹(𝑑) = +𝐹b initial +√𝐴𝛿 + 𝐵 +where 𝛿 is abs(strain/yield strain), and A and B are internally-calculated functions of +slenderness ratio (λ) and loading history. +The member slenderness ratio λ is defined as 𝑘𝐿 +𝑟 , where k depends on end conditions, L +is the element length, and r is the radius of gyration such that 𝐴𝑟2 = 𝐼 (and 𝐼 = +min(𝐼𝑦𝑦, 𝐼𝑧𝑧)); λ will by default be calculated from the section properties and element +length using k = 1. Optionally, this may be overridden by input parameter LAMDA to +allow for different end conditions. +Optionally, the user may provide a buckling curve BCUR. The points of the curve give +compressive displacement (x-axis) versus force (y-axis); the first point should have zero +displacement and the initial buckling force. Displacement and force should both be +positive. The initial buckling force must not be greater than the yield force. +The tensile yield force (point 5 and section 16-17) is defined by +𝐹𝑦 = SIGY × 𝐴, +where yield stress SIGY is an input parameter and A is the cross-sectional area. +Following initial buckling and subsequent yield in tension, the member is assumed to +be damaged. The initial buckling curve is then scaled by input parameter CCBRF, +leading to reduced strength curves such as segments 6-7, 10-14 and 18-19. This +reduction factor is typically in the range 0.6 to 1.0 (smaller values for more slender +members). By default, CCBRF is calculated using SEAOC 1990: +CCBRF = +⎜⎜⎜⎛1 + 0.5𝜆 +𝜋√ +⎟⎟⎟⎞ +0.5𝜎𝑦⎠ +⎝ +When tensile loading is applied after buckling, the member must first be straightened +before the full tensile yield force can be developed. This is represented by a reduced +unloading stiffness (e.g. segment 14-15) and the tensile reloading curve (segments 8-9 +and 15-16). Further details can be found in Bruneau, Uang, and Whittaker [1998] and +Structural Engineers Association of California [1974, 1990, 1996]. +Solid line: λ = 25 (stocky) +Dashed +line: +(slender) +λ = 120 +Figure M171-2. +The response of stocky (low λ) and slender (high λ) braces are compared in the graph. +These differences are achieved by altering the input value LAMDA (or the section +properties of the beam) and FBUCK. +*MAT_STEEL_CONCENTRIC_BRACE +Axial Strain and Internal Energy may be plotted from the INTEGRATED beam results +menus in Oasys Ltd. Post processors: D3PLOT and T/HIS. +FEMA thresholds are the total axial strains (defined by change of length/initial length) +at which the element is deemed to have passed from one category to the next, e.g. +“Elastic”, “Immediate Occupancy”, “Life Safe”, etc. During the analysis, the maximum +tensile and compressive strains (“high tide strains”) are recorded. These are checked +against the user-defined limits TS1 to TS4 and CS1 to CS4. The output flag is then set to +0, 1, 2, 3, or 4 according to which limits have been passed. The value in the output files +is the highest such flag from tensile or compressive strains. To plot this data, select +INTEGRATED beam results, Integration point 4, Axial Strain. +Maximum plastic strains in tension and compression are also output. These are defined +as maximum total strain to date minus the yield or first buckling strain for tensile and +compressive plastic strains respectively. To plot these, select INTEGRATED beam +results, Integration point 4, “shear stress XY” and “shear stress XZ” for tensile and +compressive plastic strains, respectively. +*MAT_172 +This is Material Type 172, for shell and Hughes-Liu beam elements only. The material +model can represent plain concrete only, reinforcing steel only, or a smeared +combination of concrete and reinforcement. The model includes concrete cracking in +tension and crushing in compression, and reinforcement yield, hardening and failure. +Properties are thermally sensitive; the material model can be used for fire analysis. +Material data and equations governing the behavior (including thermal properties) are +taken from Eurocode 2 (EC2). See notes below for more details of how the standard is +applied in the material model. Although the material model offers many options, a +reasonable response may be obtained by entering only RO, FC and FT for plain +concrete; if reinforcement is present, YMREINF, SUREINF, FRACRX, FRACRY must be +defined. Note that, from release R10 onwards, the number of possible cracks has been +increased from 2 (0 and 90 degrees) to 4 – see notes below. +NOTE: This material does not support specification of a ma- +terial angle, 𝛽𝑖, for each through-thickness integra- +tion point of a shell. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +FC +F +4 +FT +F +5 +6 +7 +8 +TYPEC +UNITC +ECUTEN +FCC +F +F +F +F +Default +none +none +none +0.0 +1.0 +1.0 +0.0025 +FC + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ESOFT +LCHAR +MU +TAUMXF TAUMXC ECRAGG +AGGSZ +UNITL +Type +F +F +F +F +F +F +F +F +Default +See +notes +0.0 +0.4 +1020 +1.161 +× FT +0.001 +0.0 +1.0 +Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +YMREINF PRREINF SUREINF +TYPER +FRACRX +FRACY +LCRSU +LCALPS +Type +F +F +F +F +F +F +I +I +Default +none +0.0 +0.0 +1.0 +0.0 +0.0 +none +none + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +AOPT +ET36 +PRT36 +ECUT36 +LCALPC DEGRAD +ISHCHK +UNLFAC +Type +F +F +F +F +I +F +Default +0.0 +0.0 +0.25 +1020 +none +0.0 +Additional card for AOPT > 0. + Card 5 +Variable +1 +XP +Type +F +2 +YP +F +3 +ZP +F +4 +A1 +F +5 +A2 +F +6 +A3 +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +I +0 +F +0.5 +7 +8 +Additional card for AOPT > 0. + Card 6 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +BETA +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Omit if ISHCHK = 0 + Card 7 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TYPSEC +P_OR_F +EFFD +GAMSC +ERODET +ERODEC +ERODER +TMPOFF +Type +F +F +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +2.0 +0.01 +0.05 +0.0 +Additional card for TYPEC = 6 or 9. + Card 8 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ECI_6 +ECSP69 GAMCE9 +PHIEF9 +Type +F +F +F +F +Default +see +notes +see +notes +0.0 +0.0 +Define this card only if FT is negative. + Card 9 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FT2 +FTSHR +LCFTT WRO_G +ZSURF +Type +F +F +F +F +F +Default abs(FT) abs(FT2) +0.0 +0.0 +0.0 +VARIABLE +DESCRIPTION +MID +RO +FC +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Compressive strength of concrete (stress units). +depends on TYPEC. + Meaning +TYPEC = 1,2,3,4,5,7,8: FC is the actual compressive strength +TYPEC = 6: +TYPEC = 9: +is +FC +strength used in Mander equations. +the unconfined compressive +FC is the characteristic compressive +strength (fck in EC2 1-1). See also FCC +and the notes below. +FT +Tensile stress to cause cracking. Negative value to read card 9. +TYPEC +Concrete +relationships +aggregate +type +for +stress-strain-temperature +EQ.1.0: Siliceous (default), Draft EC2 Annex (fire engineering) +EQ.2.0: Calcareous, Draft EC2 Annex (fire engineering) +EQ.3.0: Non-thermally-sensitive using ET3, ECU3 +EQ.4.0: Lightweight +EQ.5.0: Fiber-reinforced +EQ.6.0: Non-thermally-sensitive, Mander algorithm +EQ.7.0: Siliceous, EC2 1-2:2004 (fire engineering) +EQ.8.0: Calcareous, EC2 1-2:2004 (fire engineering) +EQ.9.0: EC2 1-1:2004 (general and buildings) +To obtain the pre-R9 behaviour, i.e. maximum of 2 cracks, add +100 to TYPEC. For example, 109 means 2 cracks, EC2 1-1:2004 +(general and buildings). +VARIABLE +UNITC +DESCRIPTION +Factor to convert stress units to MPa (used in shear capacity +checks and for application of EC2 formulae when TYPEC = 9) e.g. +if model units are Newtons and metres, UNITC=10^-6. +ECUTEN +Strain to fully open a crack. +FCC +Relevant only if TYPEC = 6 or 9. +TYPEC = 6: +FCC is the compressive strength of confined +concrete used in Mander equations. Default: un- +confined properties are assumed. +TYPEC = 9: +FCC is the actual compressive strength. If +blank, this will be set equal to the mean compres- +sive strength (fcm in EC2 1-1) as required for ser- +viceability calculations (8MPa greater than FC). For +ultimate load calculations the user may set FCC to a +factored characteristic compressive strength. See +notes below. +ESOFT +Tension stiffening (Slope of stress-strain curve post-cracking in +tension) +MU +Friction on crack planes (max shear = 𝜇 × compressive stress) +TAUMXF +TAUMXC +ECRAGG +AGGSZ +UNITL +Maximum friction shear stress on crack planes (ignored if +AGGSZ > 0 - see notes). +Maximum through-thickness shear stress after cracking . +Strain parameter for aggregate interlock (ignored if AGGSZ > 0 - +see notes). +Aggregate size (length units - used in NS3473 aggregate interlock +formula - see notes). +Factor to convert length units to millimeters (used only if +AGGSZ > 0 + if model unit is meters, +UNITL = 1000. + - see notes) e.g. +LCHAR +Characteristic length at which ESOFT applies, also used as crack +spacing in aggregate-interlock calculation +*MAT_CONCRETE_EC2 +DESCRIPTION +YMREINF +Young’s Modulus of reinforcement +PRREINF +Poisson’s Ratio of reinforcement +SUREINF +Ultimate stress of reinforcement +TYPER +Type of reinforcement for stress-strain-temperature relationships +EQ.1.0: Hot rolled reinforcing steel, Draft EC2 Annex (fire) +EQ.2.0: Cold worked reinforcing steel (default), Draft EC2 +Annex (fire) +EQ.3.0: Quenched/tempered prestressing steel, Draft EC2 +Annex (fire) +EQ.4.0: Cold worked prestressing steel, Draft EC2 Annex (fire) +EQ.5.0: Non-thermally sensitive using loadcurve LCRSU. +EQ.7.0: Hot rolled reinforcing steel, EC2 1-2:2004 (fire) +EQ.8.0: Cold worked reinforcing steel, EC2 1-2:2004 (fire) +Fraction of reinforcement (𝑥-axis). For example, to obtain 1% +reinforcement set FRACR = 0.01. +Fraction of reinforcement (𝑦-axis). For example, to obtain 1% +reinforcement set FRACR = 0.01. +Loadcurve for TYPER = 5, giving non-dimensional factor on +SUREINF versus plastic +stress-strain +relationships from EC2). +(overrides +strain +FRACRX +FRACRY +LCRSU +LCALPS +Optional loadcurve giving thermal expansion coefficient of +reinforcement vs temperature – overrides relationship from EC2. +VARIABLE +AOPT +DESCRIPTION +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the shell ele- +ment normal by an angle BETA. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector 𝐯 with the +element normal. +LT.0.0: This option has not yet been implemented for this +material model. +ET36 +Young’s Modulus of concrete (TYPEC = 3 and 6). For other +values of TYPEC, the Young’s Modulus is calculated internally: +see notes. +PRT36 +Poisson’s Ratio of concrete (TYPEC = all). +ECUT36 +Strain to failure of concrete in compression (TYPEC = 3 and 6). +LCALPC +DEGRAD +ISHCHK +Optional loadcurve giving thermal expansion coefficient of +concrete vs temperature – overrides relationship from EC2. +If non-zero, the compressive strength of concrete parallel to an +open crack will be reduced . +Set this flag to 1 to input Card 7 (shear capacity check and other +optional input data). +UNLFAC +Stiffness degradation factor after crushing (0.0 to 1.0 – see notes). +XP, YP, ZP +Not used. +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3. +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2. +BETA +*MAT_CONCRETE_EC2 +DESCRIPTION +Material angle in degrees for AOPT = 0 and AOPT = 3. BETA +may be overridden on the element card, see *ELEMENT_- +SHELL_BETA +TYPESC +Type of shear capacity check +EQ.1.0: BS 8110 +EQ.2.0: ACI +P_OR_F +EFFD +If BS8110 shear check, percent reinforcement – e.g. if 0.5%, input +0.5. If ACI shear check, ratio (cylinder strength/FC) - defaults to +1. +Effective section depth (length units), used in shear capacity +check. This is usually the section depth excluding the cover +concrete. +GAMSC +Load factor used in BS8110 shear capacity check. +ERODET +Crack-opening strain at which element is deleted +ERODEC +Compressive strain used in erosion criteria, see notes +ERODER +Reinforcement plastic strain used in erosion criteria, see notes +TMPOFF +Constant to be added to the model’s temperature unit to convert +into degrees Celsius, e.g., if the model’s temperature unit is + Degrees Celsius +degrees Kelvin, set TMPOFF +temperatures are then used throughout the material model, e.g., +for LCALPC as well as for the default thermally-sensitive +properties. +-273. +to +EC1_6 +Strain at maximum compressive stress for Type 6 concrete. +ECSP69 +Spalling strain in compression for TYPEC = 6 and 9. +GAMCE9 +Material factor that divides the Youngs Modulus (TYPEC = 9). +PHIEF9 +Effective creep ratio (TYPEC = 9). +FT2 +Tensile strength used for calculating tensile response. +FTSHR +Tensile strength used for calculating post-crack shear response. +LCFTT +Loadcurve defining factor on tensile strength versus time. +VARIABLE +DESCRIPTION +WRO_G +Density times gravity for water pressure in cracks +ZSURF +Z-coordinate of water surface (for water pressure in cracks) +Remarks: +reinforced concrete with evenly distributed +This material model can be used to represent unreinforced concrete (FRACR = 0), steel +(FRACR = 1), or +reinforcement +(0 < FRACR < 1). Concrete is modelled as an initially-isotropic material with a non- +rotating smeared crack approach in tension, together with a plasticity model for +compressive loading. Reinforcement is treated as separate sets of bars in the local +element x and y axes. The reinforcement is assumed not to carry through-thickness +shear or in-plane shear. Therefore, this material model should not be used to model +steel-only sections, i.e. do not create a section in which all the integration points are of +*MAT_172 with FRACRX, FRACRY = 1. +Creating Reinforced Concrete Sections: +Reinforced concrete sections for shell or beam elements may be created using *PART_ +COMPOSITE (for shells) or *INTEGRATION_BEAM (for beams) to define the section. +Create one Material definition representing the concrete using MAT_CONCRETE_EC2 +with FRACR = 0. Create another Material definition representing the reinforcement +using MAT_CONCRETE_EC2 with FRACRX and/or FRACRY = 1. The Material ID of +each integration point is then set to represent either concrete or steel. The position of +each integration point within the cross-section and its cross-sectional area are chosen to +represent the actual distribution of reinforcement. +Options for TYPEC and TYPER +Eurocode 2 (EC2) contains different sections applicable to general structural +engineering versus fire engineering. The latter contains different data for different +types of concrete and steel, and has been revised during its history. TYPEC and TYPER +control the version and section of the EC2 document from which the material data is +taken, and the types of concrete and steel being represented. In the descriptions of +TYPEC and TYPER above, “Draft EC2 Annex (fire engineering)” means data taken from +the 1995 draft Eurocode 2 Part 1-2 (for fire engineering), ENV 1992-1-2:1995. These are +the defaults, and are suitable for general use where elevated temperatures are not +considered. +EC2 was then issued in 2004 (described above as EC2 1-2:2004 (fire)) with revised stress- +strain data at elevated temperatures (TYPEC and TYPER = 7 or 8). These settings are +recommended for analyses with elevated temperatures. +Meanwhile Eurocode 2 Part 1-1 (for general structural engineering), EC2 1-1:2004, +contains material data and formulae that differ from Part 1-2; these are obtained by +setting TYPEC = 9. This setting is recommended where compatibility is required with +the structural engineering data and assumptions of Part 1-1 of the Eurocode. +A further option for modelling concrete, TYPEC = 6, is provided for applications such +as seismic engineering in which the different stress-strain behaviors of confined versus +unconfined concrete needs to be captured. This option uses equations by Mander et al, +and does not relate directly to Eurocode 2. +Material Behavior: Concrete +Thermal sensitivity +For TYPEC = 1,2,4,5,7,8, the material properties are thermally-sensitive. + If no +temperatures are defined in the model, it behaves as if at 20degC. Pre-programmed +relationships between temperature and concrete properties are taken from the EC2 +document. The thermal expansion coefficient is as defined in EC2, is non-zero by +default, and is a function of temperature. This may be overridden by inputting the +curve LCALPC. TYPEC = 3, 6 and 9 are not thermally sensitive and have no thermal +expansion coefficient by default. +Tensile response +The concrete is assumed to crack in tension when the maximum in-plane principal +stress reaches FT. A non-rotating smeared crack approach is used. Cracks can open +and close repeatedly under hysteretic loading. When a crack is closed it can carry +compression according to the normal compressive stress-strain relationships. The +direction of the crack relative to the element coordinate system is stored when the crack +first forms. The material can carry compression parallel to the crack even when the +crack is open. Further cracks may then form at pre-determined angles to the first crack, +if the tensile stress in that direction reaches FT. In versions up to R9.0, the number of +further cracks is limited to one, at 90 degrees to the first crack. In versions starting from +R10, up to three further cracks can form, at 45, 90 amd 135 degrees to the first crack. +The tensile stress is limited to FT only in the available crack directions. The tensile +stress in other directions is unlimited, and could exceed FT. This is a limitation of the +non-rotating crack approach and may lead to models being non-conservative, i.e. the +response is stronger than implied by the input. The increase of the possible number of +cracks from two to four significantly reduces this error, and may therefore cause models +to seem “weaker” in R10 than in R9 under some loading conditions. An option to revert +to the previous 2-crack behaviour is available in R10 – add 100 to TYPEC. +After initial cracking, the tensile stress reduces with increasing tensile strain. A finite +amount of energy must be absorbed to create a fully open crack - in practice the +reinforcement holds the concrete together, allowing it to continue to take some tension +(this effect is known as tension-stiffening). The options available for the stress-strain +relationship are shown below. The bilinear relationship is used by default. The simple +linear relationship applies only if ESOFT > 0 and ECUTEN = 0. +Figure M172-1. Tensile Behaviour of Concrete +LCHAR can optionally be used to maintain constant energy per unit area of crack +irrespective of mesh size, i.e. the crack opening displacement is fixed rather than the +crack opening strain. LCHAR × ECUTEN is then the displacement to fully open a +crack. For the actual elements, crack opening displacement is estimated by strain × +√area. Note that if LCHAR is defined, it is also used as the crack spacing in the NS 3473 +aggregate interlock calculation. +For the thermally-sensitive values of TYPEC, the relationship of FT with temperature is +taken from EC2 – there is no input option to change this. FT is assumed to remain at its +input value at temperatures up to 100°C, then to reduce linearly with temperature to +zero at 600°C. Up to 500°C, the crack opening strain ECUTEN increases with +temperature such that the fracture energy to open the crack remains constant. Above +500 deg C the crack opening strain does not increase further. +In some concrete design codes and standards, it is stipulated that the tensile strength of +concrete should be assumed to be zero. However, for MAT_CONCRETE_EC2 it is not +recommended to set FT to zero, because: +•Cracks will form at random orientations caused by small dynamic tensile stresses, +leading to unexpected behavior when the loading increases because the crack +orientations are fixed when the cracks first form; +•The shear strength of cracked concrete may then also become zero in the analysis +(according to the aggregate interlock formula, the post-crack shear strength is +assumed proportional to FT). +These problems may be tackled by using the inputs on Card 9. Firstly, separate tensile +strengths may be input for the tensile response and for calculating the shear strength of +cracked concrete. Secondly, by using the loadcurve LCFTT, the tensile strength may be +ramped gradually down to zero after the static loads have been applied, ensuring that +the cracks will form in the correct orientation +Compressive response: TYPEC = 1,2,4,5,7,8 +For TYPEC = 1,2,4,5,7,8, the compressive behavior of the concrete initially follows a +stress-strain curve defined in EC2 as: +Stress = FCmax × +) × +𝜀cl +⎡( +⎢ +⎣ +2 + ( 𝜀 +𝜀cl +) +⎤ +⎥ +⎦ +where 𝜀cl is the strain at which the ultimate compressive strength FCmax is reached, and +𝜀 is the current equivalent uniaxial compressive strain. +The initial elastic modulus is given by 𝐸 = 3 × FCmax/2𝜀cl. On reaching FCmax, the stress +decreases linearly with increasing strain, reaching zero at a strain 𝜀cu. Strains 𝜀cl and 𝜀cu +are by default taken from EC2 and are functions of temperature. At 20oC they take +values 0.0025 and 0.02 respectively. FCmax is also a function of temperature, given by +the input parameter FC (which applies at 20oC) times a temperature-dependent +softening factor taken from EC2. The differences between TYPEC = 1,2,4,5,7,8 are +limited to (a) different reductions of FC at elevated temperatures, and (b) different +values of 𝜀cl at elevated temperatures. +Figure M172-2. Concrete stress strain behavior +Compressive response: TYPEC = 3 +For TYPEC = 3, the user over-rides the default values of Young’s Modulus and 𝜀cu +using ET36 and ECUT36 respectively. In this case, the strain 𝜀cl is calculated from the +elastic stiffness, and there is no thermal sensitivity. The stress-strain behaviour follows +the same form as described above. +Compressive response: TYPEC = 6 +For TYPEC = 6, the above compressive crushing behaviour is replaced with the +equations proposed by Mander. This algorithm can model unconfined or confined +concrete; for unconfined, leave FCC blank. For confined concrete, input the confined +compressive strength as FCC. +Figure M172-3. Type 6 concrete +Default values for type 6 are calculated as follows: +𝜀cl = 0.002 × [1 + 5 ( +FCC6 +FC +− 1)] +𝜀cu = 1.1 × 𝜀c +𝜀csp = 𝜀cu + 2 +FCC +Note that for unconfined concrete, FCC6 = FC causing 𝜀cl to default to 0.002. +Compressive response: TYPEC = 9 +For TYPEC = 9, the input parameter FC is the characteristic cylinder strength in the +stress units of the model. FC x UNITC is assumed to be fck, the strength class in MPa +units. The mean tensile strength fctm, mean Young’s Modulus Ecm, and the strains used +to construct the stress-strain curve such as 𝜀cl are by default evaluated automatically +from tabulated functions of fck given in Table 3.1 of EC2. The compressive strength of +the material is given by the input parameter FCC, which defaults to the mean +compressive strength fcm defined in EC2 as fck + 8MPa). The user may override the +default compressive strength by inputting FCC explicitly. The stress-strain curve +follows this form: +𝑆𝑡𝑟𝑒𝑠𝑠 +𝐹𝐶𝐶 += +𝑘𝜂 − 𝜂2 +1 + (𝑘 − 2)𝜂 +Where FCC is the input parameter FCC (default: = (fck + 8MPa)/UNITC), +𝜼 = 𝒔𝒕𝒓𝒂𝒊𝒏/𝜺cl, +𝒌 = 𝟏. 𝟎𝟓𝑬 × +𝜺𝒄𝟏 +𝑭𝑪𝑪⁄ +E is the Young’s Modulus. +The default parameters are intended to be appropriate for a serviceability analysis +(mean properties), so default FT = fctm and default E = Ecm. For an ultimate load +analysis, FCC should be the “design compressive strength” (normally the factored +characteristic strength, including any appropriate material factors); FT should be input +as the factored characteristic tensile strength; GAMCE9 may be input (a material factor +that divides the Young’s Modulus so E = Ecm/GAMCE9); and a creep factor PHIEF9 +may be input: this scales 𝜺cl by (1+PHIEF9). +Unload/reload stiffness (all concrete types): +During compressive loading, the elastic modulus will be reduced according to the +parameter UNLFAC (default = 0.5). UNLFAC = 0.0 means no reduction, i.e. the initial +elastic modulus will apply during unloading and reloading. UNLFAC = 1.0 means that +unloading results in no permanent strain. Intermediate values imply a permanent +strain linearly interpolated between these extremes. +Figure M172-4. Concrete unloading behavior +Tensile strength is reduced by the same factor as the elastic modulus as described in the +paragraph above. +Optional compressive strength degradation due to cracking: +By default, the compressive strength of cracked and uncracked elements is the same. If +DEGRAD is non-zero, the formula from BS8110 is used to reduce compressive strength +parallel to the crack while the crack is open: +Reduction factor = min (1.0, +1.0 +0.8 + 100𝜀𝑡 +) , +where 𝜀𝑡 is the tensile strain normal to the crack. +Shear strength on crack planes: +Before cracking, the through-thickness shear stress in the concrete is unlimited. For +cracked elements, shear stress on the crack plane (magnitude of shear stress including +element-plane and through-thickness terms) is treated in one of two ways: +1. +If AGGSZ > 0, the relationship from Norwegian standard NS3473 is used to +model the aggregate-interlock that allows cracked concrete to carry shear load- +ing. In this case, UNITL must be defined. This is the factor that converts model +length units to millimetres, i.e. the aggregate size in millimetres = AGGSZ × +UNITL. The formula in NS3473 also requires the crack width in millimetres: +this is estimated from UNITL × 𝜀cro × 𝐿𝑒, here 𝜀cro is the crack opening strain +and 𝐿𝑒 is the crack spacing, taken as LCHAR if non-zero, or equal to element +size if LCHAR is zero. Optionally, TAUMXC may be used to set the maximum +shear stress when the crack is closed and the normal stress is zero – by default +this is equal to 1.161FT from the formulae in NS3473. If TAUMXC is defined, +the shear stress from the NS3473 formula is scaled by TAUMXC / 1.161FT. +2. +If AGGSZ = 0, the aggregate interlock is modeled by this formula: +𝜏max = +TAUMXC +𝜀cro +ECRAGG +1.0 + ++ min(MU × 𝜎comp,TAUMXF) +Where 𝜏max is the maximum shear stress carried across a crack; 𝜎compis the +compressive stress across the crack (this is zero if the crack is open); ECRAGG +is the crack opening strain at which the input shear strength TAUMXC is +halved. Again, TAUMXC defaults to 1.161FT. +Note that if a shear capacity check is specified, the above applies only to in-plane shear, +while the through-thickness shear is unlimited. +Reinforcement +The reinforcement is treated as separate bars providing resistance only in the local 𝑥 +and 𝑦 directions – it does not carry shear in-plane or out of plane. +For TYPER = 1,2,3,4,7,8, the behaviour is thermally sensitive and follows stress-strain +relationships of a form defined in EC2. At 20oC (or if no thermal input is defined) the +behaviour is elastic-perfectly-plastic with Young’s Modulus EREINF and ultimate stress +SUREINF, up to the onset of failure, after which the stress reduces linearly with +increasing strain until final failure. At elevated temperatures there is a nonlinear +transition between the elastic phase and the perfectly plastic phase, and EREINF and +SUREINF are scaled down by temperature-dependent factors defined in EC2. The +strain at which failure occurs depends on the reinforcement type (TYPER) and the +temperature. For example, for hot-rolled reinforcing steel at 20oC failure begins at 15% +strain and is complete at 20% strain. The thermal expansion coefficient is as defined in +EC2 and is a function of temperature. This may be overridden by inputting the curve +LCAPLS. The differences between TYPER = 1,2,4,7,8 are limited to (a) different +reductions of EREINF and SUREINF at elevated temperatures, (b) different nonlinear +transitions between elastic and plastic phases and (c) the strains at which softening +begins and is complete. +The default stress-strain curve for reinforcement may be overridden using TYPER = 5 +and LCRSU. In this case, the reinforcement properties are not temperature-sensitive +and the yield stress is given by SUREINF × 𝑓 (𝜀𝑝), where 𝑓 (𝜀𝑝) is the loadcurve value at +the current plastic strain. To include failure of the reinforcement, the curve should +reduce to zero at the desired failure strain and remain zero for higher strains. Note that +by default LS-DYNA re-interpolates the input curve to have 100 equally-spaced points; +if the last point on the curve is at very high strain, then the initial part of the curve may +become poorly defined. +Local directions: +AOPT and associated data are used to define the directions of the reinforcement bars. If +the reinforcement directions are not consistent across neighbouring elements, the +response may be less stiff than intended – this is equivalent to the bars being bent at the +element boundaries. See material type 2 for description of the different AOPT settings. +Shear capacity check: +Shear reinforcement is not included explicitly in this material model. However, a shear +capacity check can be made, to show regions that require shear reinforcement. The +assumption is that the structure will not yield or fail in through-thickness shear, +because sufficient shear reinforcement will be added. Set ISHCHK and TYPESC to 1. +Give the percentage reinforcement (P_OR_F), effective depth of section EFFD (this +typically excludes the cover concrete), and load factor GAMSC. These are used in Table +3.8 of BS 8110-1:1997 to determine the design shear stress. The “shear capacity” is this +design shear stress times the total section thickness (i.e. force per unit width), modified +according to Equation 6b of BS 8110 to allow for axial load. The “shear demand” (actual +shear force per unit width) is then compared to the shear capacity. This process is +performed for the two local directions of the reinforcement in each element; when +defining sections using integration rules and multiple sets of material properties, it is +important that each set of material properties referenced within the same section has the +same AOPT and orientation data. Note that the shear demand and axial load (used in +calculation of the shear capacity) are summed across the integration points within the +section; the same values of capacity, demand, and difference between capacity and +demand are then written to all the integration points. +*MAT_CONCRETE_EC2 +By default, thermal expansion properties from EC2 are used. If no temperatures are +defined in the model, properties for 20deg C are used. For TYPEC = 3, 6 or 9, and +TYPER = 5, there is no thermal expansion by default, and the properties do not vary +with temperature. The user may override the default thermal expansion behaviour by +defining curves of thermal expansion coefficient versus temperature (LCALPC, +LCALPR). These apply no matter what types TYPEC and TYPER have been selected. +Output: +“Plastic Strain” is the maximum of the plastic strains in the reinforcement in the two +local directions. +Element deletion: +Elements are deleted from the calculation when all of their integration points have +reached the erosion criterion: +Concrete crack opening strain > ERODET + or Concrete compressive strain > εc_erode +where εc_erode = ERODEC + εcsp with εcsp the strain at which the stress-strain relation falls +to zero. +Reinforcement plastic strain > εr_erode +where = ERODER + εrsp with εrsp the strain at which the stress-strain relation falls to +zero, or if LCRSU > 0 εrsp is assumed to be 2.0. +If the material is smeared concrete/reinforcement, i.e. 0 < max(FRACRX, FRACRY) < 1, +the erosion criteria must be met for both concrete and reinforcement before erosion can +occur +Extra history variables may be requested for shell elements (NEIPS on *DATABASE_- +EXTENT_BINARY), which have the following meaning: +Extra Variable 1: Current crack opening strain (if two cracks are present, max +of the two) +Extra Variable 2: Equivalent uniaxial +strain +for +concrete +compressive +behaviour +Extra Variable 3: Number of cracks (0, 1 or 2) +Extra Variable 4: Temperature +Extra Variable 5: Thermal strain +Extra Variable 6: Current crack opening strain – first crack to form +Extra Variable 7: Current crack opening strain – crack at 90 degrees to first +crack +Extra Variable 8: Max crack opening strain – first crack to form +Extra Variable 9: Max crack opening strain – crack at 90 degrees to first crack +Extra Variable 10: Maximum difference (shear demand minus capacity) that has +occurred so far, in either of the two reinforcement directions +Extra Variable 11: Maximum difference (shear demand minus capacity) that has +occurred so far, in reinforcement 𝑥-direction +Extra Variable 12: Maximum difference (shear demand minus capacity) that has +occurred so far, in reinforcement 𝑦-direction +Extra Variable 13: Current shear demand minus capacity, in reinforcement 𝑥- +direction +Extra Variable 14: Current shear demand minus capacity, in reinforcement 𝑦- +direction +Extra Variable 15: Current shear capacity 𝑉cx, in reinforcement 𝑥-direction +Extra Variable 16: Current shear capacity 𝑉cy, in reinforcement 𝑦-direction +Extra Variable 17: Current shear demand 𝑉x, in reinforcement 𝑥-direction +Extra Variable 18: Current shear demand 𝑉y, in reinforcement 𝑦-direction +Extra Variable 19: Maximum shear demand that has occurred so far, in +reinforcement x-direction +Extra Variable 20: Maximum shear demand) that has occurred so far, in +reinforcement y-direction +Extra Variable 21: Current strain in reinforcement (𝑥-direction) +Extra Variable 22: Current strain in reinforcement (𝑦-direction) +Extra Variable 23: Engineering shear strain (slip) across first crack +Extra Variable 24: Engineering shear strain (slip) across second crack +Extra Variable 25: 𝑥-stress in concrete (element local axes) +Extra Variable 26: 𝑦-stress in concrete (element local axes) +Extra Variable 27: 𝑥𝑦-stress in concrete (element local axes) +Extra Variable 28: 𝑦𝑧-stress in concrete (element local axes) +Extra Variable 29: 𝑥𝑧-Stress in concrete (element local axes) +Extra Variable 30: Reinforcement stress (𝑎-direction) +Extra Variable 31: Reinforcement stress (𝑏-direction) +Extra Variable 32: Current shear demand 𝑉max +Extra Variable 33: Maximum 𝑉max that has occurred so far +Extra Variable 34: Current shear capacity 𝑉cθ +Extra Variable 35: Excess shear: 𝑉max − 𝑉cθ +Extra Variable 36: Maximum excess shear that has occurred so far +In the above list 𝑉max is given by +𝑉max = √𝑉𝑥 +2 +2 + 𝑉𝑦 +Where 𝑉𝑥 and 𝑉𝑦 is the shear demand reinforcement in 𝑥 and 𝑦 directions respectively. +Additionally, +𝑉𝑐𝜃 = +√ +√√ +⎷ +𝑉max +) +( +𝑉𝑥 +𝑉𝑐𝑥 ++ ( +𝑉𝑦 +𝑉𝑐𝑦 +) +where 𝑉𝑐𝑥, 𝑉𝑐𝑦 are the shear capacities in the 𝑥 and 𝑦 directions. +Note that the concrete stress history variables are stored in element local axes +irrespective of AOPT, i.e. local 𝑥 is always the direction from node 1 to node 2. The +reinforcement stresses are in the reinforcement directions; these do take account of +AOPT. +MAXINT (shells) and/or BEAMIP (beams) on *DATABASE_EXTENT_BINARY may be +set to the maximum number of integration points, so that results for all integration +points can be plotted separately. +*MAT_173 +This is Material Type 173 for solid elements only, is intended to represent sandy soils +and other granular materials. Joints (planes of weakness) may be added if required; the +material then represents rock. The joint treatment is identical to that of *MAT_JOINT- +ED_ROCK. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +RO +GMOD +RNU +(blank) +PHI +CVAL +PSI +Type +A8 +F +F +F +F +F +F +Default +0.0 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NOVOID NPLANES +(blank) +LCCPDR +LCCPT +LCCJDR +LCCJT +LCSFAC +Type +Default +1 +0 + Card 3 +1 +I +0 +2 +3 +I +0 +4 +I +0 +5 +I +0 +6 +I +0 +7 +I +0 +8 +Variable GMODDP GMODGR LCGMEP +LCPHIEP +LCPSIEP +LCGMST CVALGR +ANISO +Type +F +F +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +1.0 +Plane Cards. Repeat for each plane (maximum 6 planes). + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DIP +DIPANG +CPLANE FRPLANE +TPLANE SHRMAX +LOCAL +Type +F +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +1.e20 +0.0 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +GMOD +Elastic shear modulus +RNU +PHI +Poisson’s ratio +Angle of friction (radians) +CVAL +Cohesion value (shear strength at zero normal stress) +PSI +Dilation angle (radians) +NOVOID +Flag = 1 to switch off voiding behavior +NPLANES +Number of joint planes (maximum 6) +LCCPDR +Load curve for extra cohesion for parent material (dynamic +relaxation) +LCCPT +Load curve for extra cohesion for parent material (transient) +LCCJDR +Load curve for extra cohesion for joints (dynamic relaxation) +LCCJT +Load curve for extra cohesion for joints (transient) +LCSFAC +Load curve giving factor on strength vs. time +GMODDP +Z-coordinate at which GMOD and CVAL are correct +GMODGR +Gradient of GMOD versus z-coordinate (usually negative) +VARIABLE +DESCRIPTION +LCGMEP +Load curve of GMOD versus plastic strain (overrides GMODGR) +LCPHIEP +Load curve of PHI versus plastic strain +LCPSIEP +Load curve of PSI versus plastic strain +LCGMST +(Leave blank) +CVALGR +Gradient of CVAL versus z-coordinate (usually negative) +ANISO +Factor applied to elastic shear stiffness in global XZ and YZ +planes +DIP +Angle of the plane in degrees below the horizontal +DIPANG +Plan view angle (degrees) of downhill vector drawn on the plane +CPLANE +Cohesion for shear behavior on plane +PHPLANE +Friction angle for shear behavior on plane (degrees) +TPLANE +Tensile strength across plane (generally zero or very small) +SHRMAX +Max shear stress on plane (upper +compression) +limit, +independent of +LOCAL +EQ.0: DIP and DIPANG are with respect to the global axes +EQ.1: DIP and DIPANG are with respect to the local element +axes +Remarks: +1. The material has a Mohr Coulomb yield surface, given by τmax = C + σntan(PHI), +where τmax = maximum shear stress on any plane, σn = normal stress on that +plane (positive in compression), C = cohesion, PHI = friction angle. The plastic +potential function is of the form βσk - σI + constant, where σk = maximum prin- +cipal stress, σi = minimum principal stress, and 𝛽 = 1+sin(PSI) +1−sin(PSI). +2. The tensile strength of the material is given by 𝜎max = 𝐶 +tan(PHI) where C is the +cohesion. After the material reaches its tensile strength, further tensile straining +leads to volumetric voiding; the voiding is reversible if the strain is reversed. +3. +If depth-dependent properties are used, the model must be oriented with the z- +axis in the upward direction. +4. Plastic strain is defined as √2 +3 𝜀𝑝𝑖𝑗𝜀𝑝𝑖𝑗, i.e. the same way as for other elasto-plastic +material models. +5. Friction and dilation angles PHI and PSI may vary with plastic strain, to model +heavily consolidated materials under large shear strains – as the strain increas- +es, the dilation angle typically reduces to zero and the friction angle to a lower, +pre-consolidation value. +6. For similar reasons, the shear modulus may reduce with plastic strain, but this +option may sometimes give unstable results. +7. The loadcurves LCCPDR, LCCPT, LCCJDR, LCCJT allow extra cohesion to be +specified as a function of time. The cohesion is additional to that specified in +the material parameters. This is intended for use during the initial stages of an +analysis to allow application of gravity or other loads without cracking or yield- +ing, and for the cracking or yielding then to be introduced in a controlled man- +ner. This is done by specifying extra cohesion that exceeds the expected +stresses initially, then declining to zero. If no curves are specified, no extra +cohesion is applied. +8. The loadcurve for factor on strength applies simultaneously to the cohesion and +tan(friction angle) of parent material and all joints. This feature is intended for +reducing the strength of the material gradually, to explore factors of safety. If +no curve is present, a constant factor of 1 is assumed. Values much greater than +1.0 may cause problems with stability. +9. The anisotropic factor ANISO applies the elastic shear stiffness in the global XZ + It can be used only in pure Mohr-Coulomb mode +and YZ planes. +(NPLANES = 0). +10. For friction angle greater than zero, the Mohr Coulomb yield surface implies a +tensile pressure limit equal to CVAL/tan(PHI). The default behaviour is that +voids develop in the material when this pressure limit is reached, and the pres- +sure will never become more tensile than the pressure limit. If NOVOID = 1, +the tensile pressure limit is not applied. Stress states in which the pressure is +more tensile than CVAL/tan(PHI) are permitted, but will be purely hydrostatic +with no shear stress. NOVOID is recommended in Multi-Material ALE simula- +tions, in which the development of voids or air space is already accounted for +by the Multi-Material ALE. +11. To model soil, set NJOINT = 0. The joints are to allow modeling of rock, and +are treated identically to those of *MAT_JOINTED_ROCK. +12. The joint plane orientations are defined by the angle of a “downhill vector” +drawn on the plane, i.e. the vector is oriented within the plane to obtain the +maximum possible downhill angle. DIP is the angle of this line below the hori- +zontal. DIPANG is the plan-view angle of the line (pointing down hill) meas- +ured clockwise from the global Y-axis about the global Z-axis. +13. Joint planes would generally be defined in the global axis system if they are +taken from survey data. However, the material model can also be used to rep- +resent masonry, in which case the weak planes represent the cement and lie +parallel to the local element axes. +14. The joint planes rotate with the rigid body motion of the elements, irrespective +of whether their initial definitions are in the global or local axis system. +15. Extra variables for plotting. By setting NEIPH on *DATABASE_EXTENT_BI- +NARY to 27, the following variables can be plotted in Oasys Ltd. Post Proces- +sors D3PLOT, T/HIS and LS-PrePost: +Variable(s) +Description +1 +2 +3 +4 – 9 +10 - 15 +16 - 20 +21 - 27 +33 +34 +mobilized strength fraction for base material +volumetric void strain +maximum stress overshoot during plastic calculation +crack opening strain for planes 1 - 6 +crack accumulated engineering shear strain for planes 1 - 6 +current shear utilization for planes 1 - 6 +maximum shear utilization to date for planes 1 – 6 +elastic shear modulus (for checking depth-dependent input) +cohesion (for checking depth-dependent input) +*MAT_RC_BEAM +This is Material Type 174, for Hughes-Liu beam elements only. The material model can +represent plain concrete only, reinforcing steel only, or a smeared combination of +concrete and reinforcement. The main emphasis of this material model is the cyclic +behavior – it is intended primarily for seismic analysis. + Card 1 +1 +Variable +MID +2 +RO +3 +EUNL +Type +A8 +F +F +4 +PR +F +5 +FC +F +6 +7 +8 +EC1 +EC50 +RESID +F +F +F +Default +none +none +See +Remarks +0.0 +none +0.0022 +See +Remarks +0.2 + Card 2 +Variable +1 +FT +2 +3 +4 +5 +6 +7 +8 +UNITC +(blank) +(blank) +(blank) +ESOFT +LCHAR +OUTPUT +Type +F +F +F +F +F +F +F +Default +See +Remarks +1.0 +none +none +none +See +Remarks +none + Card 3 +1 +2 +3 +4 +5 +6 +7 +F +0 +8 +Variable +FRACR +YMREIN +PRREIN +SYREIN +SUREIN +ESHR +EUR +RREINF +Type +F +F +F +F +F +F +F +F +Default +0.0 +none +0.0 +0.0 +SYREIN +0.03 +0.2 +4.0 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +VARIABLE +DESCRIPTION +RO +Mass density +EUNL +Initial unloading elastic modulus . +PR +FC +EC1 +EC50 +Poisson’s ratio. +Cylinder strength (stress units) +Strain at which stress FC is reached. +Strain at which the stress has dropped to 50% FC +RESID +Residual strength factor +FT +Maximum tensile stress +UNITC +Factor to convert stress units to MPa +ESOFT +Slope of stress-strain curve post-cracking in tension +LCHAR +Characteristic length for strain-softening behavior +OUTPUT +Output flag controlling what is written as “plastic strain” +EQ.0.0: Curvature +EQ.1.0: “High-tide” plastic strain in reinforcement +FRACR +Fraction of +FRACR = 0.01) +reinforcement +(e.g. +for 1% +reinforcement +YMREIN +Young’s Modulus of reinforcement +PRREIN +Poisson’s Ratio of reinforcement +SYREIN +Yield stress of reinforcement +SUREIN +Ultimate stress of reinforcement +ESHR +EUR +R_REINF +Strain at which reinforcement begins to harden +Strain at which reinforcement reaches ultimate stress +Dimensionless Ramberg-Osgood parameter r. If zero, a default +value r = 4.0 will be used. If set to -1, parameters will be +calculated from Kent & Park formulae. +Creating sections for reinforced concrete beams: +This material model can be used to represent unreinforced concrete (FRACR = 0), steel +reinforcement +(FRACR = 1), or +(0 < FRACR < 1). +reinforced concrete with evenly distributed +Alternatively, use *INTEGRATION_BEAM to define the section. A new option in +allows the user to define a Part ID for each integration point, similar to the facility +already available with *INTEGRATION_SHELL. All parts referred to by one +integration rule must have the same material type, but can have different material +properties. Create one Part for concrete, and another for steel. These Parts should +reference Materials, both of type *MAT_RC_BEAM, one with FRACR = 0, the other with +FRACR = 1. Then, by assigning one or other of these Part Ids to each integration point +the reinforcement can be applied to the correct locations within the section of the beam. +Concrete: +In monotonic compression, the approach of Park and Kent, as described in Park & +Paulay [1975] is used. The material follows a parabolic stress-strain curve up to a +maximum stress equal to the cylinder strength FC; therafter the strength decays linearly +with strain until the residual strength is reached. Default values for some material +parameters will be calculated automatically as follows: +EC50 = +(3 + 0.29𝐹𝐶) +145𝐹𝐶 − 1000 +where FC is in MPa as per Park and Kent test data. +EUNL = initial tangent slope = +2FC +EC1 +User-defined values for EUNL lower than this are not permitted, but higher values may +be defined if desired. +FT = 1.4 ( +FC +10 +) +where FC is in MPa as per Park and Kent test data. +ESOFT = EUNL +User-defined values higher than EUNL are not permitted. +UNITC is used only to calculate default values for the above parameters from FC. +Strain-softening behavior tends to lead to deformations being concentrated in one +element, and hence the overall force-deflection behavior of the structure can be mesh- +size-dependent if the softening is characterized by strain. To avoid this, a characteristic +length (LCHAR) may be defined. This is the length of specimen (or element) that +would exhibit the defined monotonic stress-strain relationship. LS-DYNA adjusts the +stress-strain relationship after ultimate load for each element, such that all elements +irrespective of their length will show the same deflection during strain softening (i.e. +between ultimate load and residual load). Therefore, although deformation will still be +concentrated in one element, the load-deflection behavior should be the same +irrespective of element size. For tensile behavior, ESOFT is similarly scaled. +MAT_RC_BEAM - concrete +17 +18 +16 +15,19 +20 +7 +7,9 +5,12 +8 +10 +11 +1 +4 +13 +3,14 +Figure M174-1 +Cyclic behavior is broadly suggested by Blakeley and Park [1973] as described in Park & +Paulay [1975]; the stress-strain response lies within the Park-Kent envelope, and is +characterized by stiff initial unloading response at slope EUNL followed by a less stiff +response if it unloads to less than half the current strength. Reloading stiffness +degrades with increasing strain. +In tension, the stress rises linearly with strain until a tensile limit FT is reached. +Thereafter the stiffness and strength decays with increasing strain at a rate ESOFT. The +stiffness also decays such that unloading always returns to strain at which the stress +most recently changed to tensile. +σult +σy +εsh +εult +Figure M174-2 +MAT_RC_BEAM – reinforcement – +RREINF = 4.0 +6,8 +3,5 +9,11 +12,14 15 +13 +7 +1 +10 +Figure M174-3 +Monotonic loading of the reinforcement results in the stress-strain curve shown, which +is parabolic between εsh and εult. The same curve acts as an envelope on the hysteretic +behavior, when the x-axis is cumulative plastic strain. +Unloading from the yielded condition is elastic until the load reverses. Thereafter, the +Bauschinger Effect (reduction in stiffness at stresses less than yield during cyclic +deformation) is represented by following a Ramberg-Osgood relationship until the +yield stress is reached: +𝜀 − 𝜀𝑠 = ( +) {1 + ( +𝜎𝐶𝐻 +𝑟−1 +) +} +where 𝜀 and 𝜎 are strain and stress, 𝜀𝑠 +and r and 𝜎𝐶𝐻 + are as defined below + is the strain at zero stress, E is Young’s Modulus, +Two options are given for calculation r and 𝜎𝐶𝐻, which is performed at each stress +reversal: +1. +2. +If RREINF is input as -1, r and σCH are calculated internally from formulae given +in Kent and Park. Parameter r depends on the number of stress reversals. +Parameter 𝜎𝐶𝐻 depends on the plastic strain that occurred between the previ- +ous two stress reversals. The formulae were statistically derived from experi- +ments, but may not fit all circumstances. In particular, large differences in +behavior may be caused by the presence or absence of small stress reversals +such as could be caused by high frequency oscillations. Therefore, results +might sometimes be unduly sensitive to small changes in the input data. +If RREINF is entered by the user or left blank, r is held constant while 𝜎𝐶𝐻 is +calculated on each reversal such that the Ramberg-Osgood curve meets the +monotonic stress-strain curve at the point from which it last unloaded, e.g. +points 6 and 8 are coincident in the graph below. The default setting +RREINF = 4.0 gives similar hysteresis behavior to that described by Kent & +Park but is unlikely to be so sensitive to small changes of input data. +Output: +It is recommended to use BEAMIP on *DATABASE_EXTENT_BINARY to request stress +and strain output at the individual integration points. If this is done, for MAT_RC_- +BEAM only, element curvature is written to the output files in place of plastic strain. In +the post-processor, select “plastic strain” to display curvature (whichever of the +curvatures about local y and z axes has greatest absolute value will be plotted). +Alternatively, select “axial strain” to display the total axial strain (elastic + plastic) at +that integration point; this can be combined with axial stress to create hysteresis plots +such as those shown above. +*MAT_VISCOELASTIC_THERMAL +This is Material Type 175. This material model provides a general viscoelastic Maxwell +model having up to 12 terms in the prony series expansion and is useful for modeling +dense continuum rubbers and solid explosives. Either the coefficients of the prony +series expansion or a relaxation curve may be specified to define the viscoelastic +deviatoric and bulk behavior. Note that *MAT_GENERAL_VISCOELASTIC (Material +Type 76) has all the capability of *MAT_VISCOELASTIC_THERMAL, and additionally +offers more terms (18) in the prony series expansion and an optional scaling of material +properties with moisture content. + Card 1 +1 +Variable +MID +2 +RO +3 +4 +BULK +PCF +Type +A8 +F +F +F +5 +EF +F +6 +TREF +F +7 +A +F +8 +B +F +If fitting is done from a relaxation curve, specify fitting parameters on card 2, otherwise +if constants are set on Viscoelastic Constant Cards LEAVE THIS CARD BLANK. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCID +NT +BSTART +TRAMP +LCIDK +NTK +BSTARTK TRAMPK +Type +F +I +F +F +F +I +F +F +Viscoelastic Constant Cards. Up to 6 cards may be input. A keyword card (with a +“*” in column 1) terminates this input if less than 6 cards are used. These cards are not +needed if relaxation data is defined. The number of terms for the shear behavior may +differ from that for the bulk behavior: simply insert zero if a term is not included. If an +elastic layer is defined you only need to define GI and KI (note in an elastic layer only +one card is needed). + Optional +Variable +Type +1 +Gi +F +2 +BETAi +F +3 +Ki +F +4 +5 +6 +7 +8 +BETAKi +VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +BULK +Elastic bulk modulus. +PCF +Tensile pressure elimination flag for solid elements only. If set to +unity tensile pressures are set to zero. +EF +Elastic flag: +EQ.0: the later is viscoelastic +EQ.1: the layer is elastic +TREF +A +B +LCID +NT +Reference temperature for shift function (must be greater than +zero). +Coefficient for the Arrhenius and the Williams-Landel-Ferry shift +functions. +Coefficient for the Williams-Landel-Ferry shift function. +Load curve ID for deviatoric behavior if constants, 𝐺𝑖, and 𝛽𝑖 are +determined via a least squares fit. This relaxation curve is shown +below. +Number of terms in shear fit. If zero the default is 6. Fewer than +NT terms will be used if the fit produces one or more negative +shear moduli. Currently, the maximum number is set to 6. +BSTART +In the fit, 𝛽1 is set to zero, 𝛽2 is set to BSTART, 𝛽3 is 10 times 𝛽2, +𝛽4 is 10 times 𝛽3 , and so on. If zero, BSTART is determined by an +iterative trial and error scheme. +TRAMP +Optional ramp time for loading. +LCIDK +Load curve ID for bulk behavior if constants, 𝐾𝑖, and 𝛽𝜅𝑖 are +determined via a least squares fit. This relaxation curve is shown +below. +NTK +Number of terms desired in bulk fit. If zero the default is 6. +Currently, the maximum number is set to 6. +BSTARTK +*MAT_VISCOELASTIC_THERMAL +DESCRIPTION +In the fit, 𝛽𝜅1 is set to zero, 𝛽𝜅2 is set to BSTARTK, 𝛽𝜅3 is 10 times +𝛽𝜅2, 𝛽𝜅4 is 10 times 𝛽𝜅3 , and so on. If zero, BSTARTK is +determined by an iterative trial and error scheme. +TRAMPK +Optional ramp time for bulk loading. +Gi +Optional shear relaxation modulus for the ith term +BETAi +Optional shear decay constant for the ith term +Ki +Optional bulk relaxation modulus for the ith term +BETAKi +Optional bulk decay constant for the ith term +σ∕ε +TRAMP +10n +10n+1 10n+2 10n+3 +time +optional ramp time for loading +Figure M175-1. Relaxation curve. This curve defines stress versus time where +time is defined on a logarithmic scale. For best results, the points defined in +the load curve should be equally spaced on the logarithmic scale. Furthermore, +Furthermore, the load curve should be smooth and defined in the positive +quadrant. If nonphysical values are determined by least squares fit, LS-DYNA +will terminate with an error message after the initialization phase is completed. +If the ramp time for loading is included, then the relaxation which occurs +during the loading phase is taken into account. This effect may or may not be +important +Remarks: +Rate effects are taken into accounted through linear viscoelasticity by a convolution +integral of the form: +𝜎𝑖𝑗 = ∫ 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) +∂𝜀𝑘𝑙 +∂𝜏 +𝑑𝜏 +where 𝑔𝑖𝑗𝑘𝑙(𝑡−𝜏) is the relaxation functions for the different stress measures. This stress is +added to the stress tensor determined from the strain energy functional. +If we wish to include only simple rate effects, the relaxation function is represented by +six terms from the Prony series: +𝑔(𝑡) = ∑ 𝐺𝑚𝑒−𝛽𝑚𝑡 +𝑚=1 +We characterize this in the input by shear moduli, 𝐺𝑖, and decay constants, 𝛽𝑖. An +arbitrary number of terms, up to 6, may be used when applying the viscoelastic model. +For volumetric relaxation, the relaxation function is also represented by the Prony series +in terms of bulk moduli: +𝑘(𝑡) = ∑ 𝐾𝑚𝑒−𝛽𝑘𝑚𝑡 +𝑚=1 +The Arrhenius and Williams-Landel-Ferry (WLF) shift functions account for the effects +of the temperature on the stress relaxation. A scaled time, t’, +𝑡′ = ∫ Φ(𝑇)𝑑𝑡 +is used in the relaxation function instead of the physical time. The Arrhenius shift +function is +Φ(𝑇) = exp [−𝐴 ( +− +𝑇REF +)] +and the Williams-Landel-Ferry shift function is +Φ(𝑇) = exp (−𝐴 +𝑇 − 𝑇REF +𝐵 + 𝑇 − 𝑇REF +) +If all three values (TREF, A, and B) are not zero, the WLF function is used; the +Arrhenius function is used if B is zero; and no scaling is applied if all three values are +zero. +. +*MAT_QUASILINEAR_VISCOELASTIC +Purpose: This is Material Type 176. This is a quasi-linear, isotropic, viscoelastic +material based on a one-dimensional model by Fung [1993], which represents biological +soft tissues such as brain, skin, kidney, spleen, etc. This model is implemented for solid +and shell elements. The formulation has recently been changed to allow larger strains, +and, in general, will not give the same results as the previous implementation which +remains the default. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +K +F +Default +none +none +none + Card 2 +1 +2 +3 +4 +5 +LC1 +LC2 +I +0 +4 +I +0 +5 +Variable +SO +E_MIN +E_MAX +GAMA1 +GAMA2 +Type +F +F +F +F +F +6 +N +F +6 +6 +K +F +7 +GSTART +F +1/TMAX +7 +EH +F +Default +0.0 +-0.9 +5.1 +0.0 +0.0 +0.0 +0.0 +Viscoelastic Constant Card 1. Additional Card for LC1 = 0. + Card 3 +Variable +1 +G1 +2 +BETA1 +Type +F +F +3 +G2 +F +4 +BETA2 +F +5 +G3 +F +6 +BETA3 +F +7 +G4 +F +8 +M +F +6 +8 +FORM +I +0 +8 +BETA4 +Viscoelastic Constant Card 2. Additional Card for LC1 = 0. + Card 4 +Variable +1 +G5 +2 +BETA5 +Type +F +F +3 +G6 +F +4 +BETA6 +F +5 +G7 +F +6 +BETA7 +F +7 +G8 +F +8 +BETA8 +F +Viscoelastic Constant Card 3. Additional Card for LC1 = 0. + Card 5 +Variable +1 +G9 +2 +3 +4 +5 +6 +7 +8 +BETA9 +G10 +BETA10 +G11 +BETA11 +G12 +BETA12 +Type +F +F +F +F +F +F +F +F +Instantaneous Elastic Reponses Card. Additional Card for LC2 = 0. +Card +Variable +1 +C1 +Type +F +2 +C2 +F +3 +C3 +F +4 +C4 +F +5 +C5 +F +6 +C6 +F +7 +8 + VARIABLE +DESCRIPTION +MID +RO +K +LC1 +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Bulk modulus. +Load curve ID that defines the relaxation function in shear. This +curve is used to fit the coefficients Gi and BETAi. If zero, define +the coefficients directly. The latter is recommended. +VARIABLE +LC2 +N +DESCRIPTION +Load curve ID that defines the instantaneous elastic response in +compression and tension. If zero, define the coefficients directly. +Symmetry is not assumed if only the tension side is define; therefore, +defining the response in tension only, may lead to nonphysical behavior +in compression. Also, this curve should give a softening response for +increasing strain without any negative or zero slopes. A stiffening +curve or one with negative slopes is generally unstable. +Number of terms used in the Prony series, a number less than or +equal to 6. This number should be equal to the number of +decades of time covered by the experimental data. Define this +number if LC1 is nonzero. Carefully check the fit in the d3hsp file +to ensure that it is valid, since the least square fit is not always +reliable. +GSTART +Starting value for least square fit. If zero, a default value is set +equal to the inverse of the largest time in the experiment. Define +this number if LC1 is nonzero. +M +SO +Number of terms used to determine the instantaneous elastic +response. This variable is ignored with the new formulation but +is kept for compatibility with the previous input. +Strain (logarithmic) output option to control what is written as +component 7 to the d3plot database. (LS-PrePost always blindly +labels this component as effective plastic strain.) The maximum +values are updated for each element each time step: +EQ.0.0: maximum principal strain that occurs during the +calculation, +EQ.1.0: maximum magnitude of the principal strain values that +occurs during the calculation, +EQ.2.0: maximum effective strain that occurs during the +calculation. +E_MIN +Minimum strain used to generate the load curve from 𝐶𝑖. The +default range is -0.9 to 5.1. The computed solution will be more +accurate if the user specifies the range used to fit the 𝐶𝑖. Linear +extrapolation is used outside the specified range. +E_MAX +Maximum strain used to generate the load curve from 𝐶𝑖. +*MAT_QUASILINEAR_VISCOELASTIC +DESCRIPTION +K +Material failure parameter that controls the volume enclosed by +the failure surface, see *MAT_SIMPLIFIED_RUBBER. +LE.0.0: ignore failure criterion; +GT.0.0: use actual K value for failure criterions. +GAMA1 +Material failure parameter, see *MAT_SIMPLIFIED_RUBBER and +Figure M181-1. +GAMA2 +Material failure parameter, see *MAT_SIMPLIFIED_RUBBER. +EH +Damage parameter, see *MAT_SIMPLIFIED_RUBBER. +FORM +Gi +BETAi +Formulation of model. FORM = 0 gives the original model +developed by Fung, which always relaxes to a zero stress state as +time approaches infinity, and FORM = 1 gives the alternative +model, which relaxes to the quasi-static elastic response. In +general, the two formulations won’t give the same responses. +Formulation, FORM = -1, is an improvement on FORM = 0 where +the instantaneous elastic response is used in the viscoelastic stress +update, not just in the relaxation, as in FORM = 0. Consequently, +the constants for the elastic response do not need to be scaled. +Coefficients of the relaxation function. The number of coefficients +is currently limited to 6 although 12 may be read in to maintain +compatibility with the previous formulation’s input. Define these +coefficients if LC1 is set to zero. At least 2 coefficients must be +nonzero. +Decay constants of the relaxation function. + Define these +coefficients if LC1 is set to zero. The number of coefficients is +currently limited to 6 although 12 may be read in to maintain +compatibility with the previous formulation’s input. +Ci +Coefficients of the instantaneous elastic response in compression +and tension. Define these coefficients only if LC2 is set to zero. +Remarks: +The equations for the original model (FORM = 0) are given as: +𝜎𝑉(𝑡) = ∫ 𝐺(𝑡 − 𝜏) +∂𝜎𝜀[𝜀(𝜏)] +∂𝜀 +∂𝜀 +∂𝜏 +𝑑𝜏 +𝐺(𝑡) = ∑ 𝐺𝑖 +𝑒−𝛽𝑡 +𝑖=1 +𝜎𝜀(𝜀) = ∑ 𝐶𝑖 +𝜀𝑖 +𝑖=1 +where G is the shear modulus. Effective strain (which can be written to the d3plot +database) is calculated as follows: +𝜀effective = √ +𝜀𝑖𝑗𝜀𝑖𝑗 +The polynomial for instantaneous elastic response should contain only odd terms if +symmetric tension-compression response is desired. +The new model (FORM = 1) is based on the hyperelastic model used *MAT_SIMPLI- +FIED_RUBBER assuming incompressibility. The one-dimensional expression for +𝜎𝜀generates the uniaxial stress-strain curve and an additional visco-elastic term is +added on, +𝜎(𝜀, 𝑡) = 𝜎𝑆𝑅(𝜀) + 𝜎𝑉(𝑡) +𝜎𝑉(𝑡) = ∫ 𝐺(𝑡 − 𝜏) +∂𝜀 +∂𝜏 +𝑑𝜏 +where the first term to the right of the equals sign is the hyperelastic stress and the +second is the viscoelastic stress. Unlike the previous formulation, where the stress +always relaxed to zero, the current formulation relaxes to the hyperelastic stress. +*MAT_HILL_FOAM +Purpose: This is Material Type 177. This is a highly compressible foam based on the +strain-energy function proposed by Hill [1979]; also see Storakers [1986]. Poisson’s ratio +effects are taken into account. +5 +6 +7 +8 +MU +LCID +FITTYPE +LCSR + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +K +F +Default +none +none +none +4 +N +F +0 +F +0 +Material Constant Card 1. Additional card for LCID = 0. + Card 2 +Variable +1 +C1 +Type +F +2 +C2 +F +3 +C3 +F +4 +C4 +F +5 +C5 +F +Material Constant Card 2. Additional card for LCID = 0. +3 +B3 +F +3 +4 +B4 +F +4 +5 +B5 +F +5 + Card 3 +Variable +1 +B1 +Type +F + Card 4 +Variable +Type +1 +R +F +2 +B2 +F +2 +M +F +I +0 +6 +C6 +F +6 +B6 +F +6 +I +0 +7 +C7 +F +7 +B7 +F +7 +I +0 +8 +C8 +F +8 +B8 +F +VARIABLE +DESCRIPTION +MID +RO +K +N +MU +LCID +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Bulk modulus. This modulus is used for determining the contact +interface stiffness. +Material constant. Define if LCID = 0 below; otherwise, N is fit +from the load curve data. See equations below. +Damping coefficient. +Load curve ID that defines the force per unit area versus the +stretch ratio. This curve can be given for either uniaxial or biaxial +data depending on FITTYPE. +FITTYPE +Type of fit: +EQ.1: uniaxial data, +EQ.2: biaxial data, +EQ.3: pure shear data. +LCSR +Load curve ID that defines the uniaxial or biaxial stretch ratio versus the transverse stretch ratio. +Material constants. See equations below. Define up to 8 +coefficients if LCID = 0. +Material constants. See equations below. Define up to 8 +coefficients if LCID = 0. +Mullins effect model r coefficient +Mullins effect model m coefficient +Ci +Bi +R +M +Remarks: +If load curve data is defined, the fit generated by LS-DYNA must be closely checked in +the D3HSP output file. It may occur that the nonlinear least squares procedure in LS- +DYNA, which is used to fit the data, is inadequate. +The Hill strain energy density function for this highly compressible foam is given by: +𝑊 = ∑ +𝑗=1 +𝐶𝑗 +𝑏𝑗 +𝑏𝑗 + 𝜆2 +𝑏𝑗 + 𝜆3 +[𝜆1 +𝑏𝑗 − 3 + +(𝐽−𝑛𝑏𝑗 − 1)] +where 𝐶𝑗, 𝑏𝑗, and n are material constants and 𝐽 = 𝜆1𝜆2𝜆3 represents the ratio of the +deformed to the undeformed state. The constant m is internally set to 4. In case +number of points in the curve is less than 8, then m is set to the number of points +divided by 2. The principal Cauchy stresses are +𝑡𝑖 = ∑ +𝑗=1 +𝐶𝑗 +𝑏𝑗 − 𝐽−𝑛𝑏𝑗] 𝑖 = 1,2,3 +[𝜆𝑖 +From the above equations the shear modulus is: +and the bulk modulus is: +𝜇 = +∑ 𝐶𝑗𝑏𝑗 +𝑗=1 +𝐾 = 2𝜇 (𝑛 + +) +The value for K defined in the input is used in the calculation of contact forces and for +the material time step. Generally, this value should be equal to or greater that the K +given in the above equation. +*MAT_VISCOELASTIC_HILL_FOAM +Purpose: This is Material Type 178. This is a highly compressible foam based on the +strain-energy function proposed by Hill [1979]; also see Storakers [1986]. The extension +to include large strain viscoelasticity is due to Feng and Hallquist [2002]. +5 +6 +7 +8 +MU +LCID +FITTYPE +LCSR +4 +N +F +0 +4 + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +K +F +Default +none +none +none + Card 2 +1 +2 +3 +Variable +LCVE +NT +GSTART +Type +Default +I +0 +F +6 +F +1/TMAX +F +0.05 +5 +Material Constant Card 1. Additional card for LCID = 0. + Card 3 +Variable +1 +C1 +Type +F +2 +C2 +F +3 +C3 +F +4 +C4 +F +5 +C5 +F +Material Constant Card 2. Additional card for LCID = 0. + Card 4 +Variable +1 +B1 +Type +F +2 +B2 +F +3 +B3 +F +4 +B4 +F +5 +B5 +F +I +0 +6 +6 +C6 +F +6 +B6 +F +I +0 +7 +7 +C7 +F +7 +B7 +F +I +0 +8 +8 +C8 +F +8 +B8 +Viscoelastic Constant Cards. Up to 12 cards may be input. A keyword card (with a +“*” in column 1) terminates this input if less than 12 cards are used. + Card 5 +Variable +Type +1 +GI +F +2 +3 +4 +5 +6 +7 +8 +BETAI +F + VARIABLE +DESCRIPTION +MID +RO +K +N +MU +LCID +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Bulk modulus. This modulus is used for determining the contact +interface stiffness. +Material constant. Define if LCID = 0 below; otherwise, N is fit +from the load curve data. See equations below. +Damping coefficient (0.05 < recommended value < 0.50; default is +0.05). +Load curve ID that defines the force per unit area versus the +stretch ratio. This curve can be given for either uniaxial or biaxial +data depending on FITTYPE. Load curve LCSR below must also +be defined. +FITTYPE +Type of fit: +EQ.1: uniaxial data, +EQ.2: biaxial data. +LCSR +LCVE +Load curve ID that defines the uniaxial or biaxial stress ratio versus the transverse stretch ratio. +Optional load curve ID that defines the relaxation function in +shear. This curve is used to fit the coefficients Gi and BETAi. If +zero, define the coefficients directly. The latter is recommended. +VARIABLE +NT +DESCRIPTION +Number of terms used to fit the Prony series, which is a number +less than or equal to 12. This number should be equal to the +number of decades of time covered by the experimental data. +Define this number if LCVE is nonzero. Carefully check the fit in +the D3HSP file to ensure that it is valid, since the least square fit is +not always reliable. +GSTART +Starting value for least square fit. If zero, a default value is set +equal to the inverse of the largest time in the experiment. Define +this number if LC1 is nonzero, Ci, Material constants. See +equations below. Define up to 8 coefficients. +Ci +Bi +GI +Material constants. See equations below. Define up to 8 +coefficients if LCID = 0. +Material constants. See equations below. Define up to 8 +coefficients if LCID = 0. +Optional shear relaxation modulus for the ith term +BETAI +Optional decay constant if ith term +Remarks: +If load curve data is defined, the fit generated by LS-DYNA must be closely checked in +the D3HSP output file. It may occur that the nonlinear least squares procedure in LS- +DYNA, which is used to fit the data, is inadequate. +The Hill strain energy density function for this highly compressible foam is given by: +𝑝𝑛+1 = 𝑝𝑛𝑒−𝛽⋅𝛥𝑡 + 𝐾𝜀̇𝑘𝑘 ( +1 − 𝑒−𝛽⋅𝛥𝑡 +) where 𝛽 = |𝐵𝐸𝑇𝐴| +where 𝐶𝑗, 𝑏𝑗, and n are material constants and 𝐽 = 𝜆1𝜆2𝜆3 represents the ratio of the +deformed to the undeformed state. The principal Cauchy stresses are +𝑡𝑖 = ∑ +𝑗=1 +𝐶𝑗 +𝑏𝑗 − 𝐽−𝑛𝑏𝑗] 𝑖 = 1,2,3 +[𝜆𝑖 +From the above equations the shear modulus is: +𝜇 = +∑ 𝐶𝑗𝑏𝑗 +𝑗=1 +and the bulk modulus is: +𝐾 = 2𝜇 (𝑛 + +) +The value for K defined in the input is used in the calculation of contact forces and for +the material time step. Generally, this value should be equal to or greater that the K +given in the above equation. +Rate effects are taken into account through linear viscoelasticity by a convolution +integral of the form: +𝜎𝑖𝑗 = ∫ 𝑔𝑖𝑗𝑘𝑙 +(𝑡 − 𝜏) +∂𝜀𝑘𝑙 +∂𝜏 +𝑑𝜏 +or in terms of the second Piola-Kirchhoff stress, 𝑆𝑖𝑗, and Green's strain tensor, 𝐸𝑖𝑗, +𝑆𝑖𝑗 = ∫ 𝐺𝑖𝑗𝑘𝑙 +(𝑡 − 𝜏) +∂ 𝐸𝑘𝑙 +∂𝜏 +𝑑𝜏 +where 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) and 𝐺𝑖𝑗𝑘𝑙(𝑡 − 𝜏) are the relaxation functions for the different stress +measures. This stress is added to the stress tensor determined from the strain energy +functional. +If we wish to include only simple rate effects, the relaxation function is represented by +six terms from the Prony series: +given by, +𝑔(𝑡) = 𝛼0 + ∑ 𝛼𝑚 +𝑚=1 +𝑒−𝛽 𝑡 +𝑔(𝑡) = ∑ 𝐺𝑖𝑒−𝛽𝑖 𝑡 +𝑖=1 +This model is effectively a Maxwell fluid which consists of a dampers and springs in +series. We characterize this in the input by shear moduli, 𝐺𝑖, and decay constants, 𝛽𝑖. +The viscoelastic behavior is optional and an arbitrary number of terms may be used. +*MAT_LOW_DENSITY_SYNTHETIC_FOAM_{OPTION} +This is Material Type 179 (and 180 if the ORTHO option below is active) for modeling +rate independent low density foams, which have the property that the hysteresis in the +loading-unloading curve is considerably reduced after the first loading cycle. In this +material we assume that the loading-unloading curve is identical after the first cycle of +loading is completed and that the damage is isotropic, i.e., the behavior after the first +cycle of loading in the orthogonal directions also follows the second curve. The main +application at this time is to model the observed behavior in the compressible synthetic +foams that are used in some bumper designs. Tables may be used in place of load +curves to account for strain rate effects. +Available options include: + +ORTHO +WITH_FAILURE +ORTHO_WITH_FAILURE +If the foam develops orthotropic behavior, i.e., after the first loading and unloading +cycle the material in the orthogonal directions are unaffected then the ORTHO option +should be used. If the ORTHO option is active the directionality of the loading is +stored. This option is requires additional storage to store the history variables related to +the orthogonality and is slightly more expensive. +An optional failure criterion is included. A description of the failure model is provided +below for material type 181, *MAT_SIMPLIFIED_RUBBER/FOAM. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +5 +LCID1 +LCID2 +F +F +Default +6 +HU +F +1. +7 +8 +BETA +DAMP +F +F +0.05 +Card 2 +1 +2 +3 +4 +5 +6 +7 +Variable +SHAPE +FAIL +BVFLAG +ED +BETA1 +KCON +REF +Type +F +F +F +F +F +F +F +8 +TC +F +Default +1.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +1.E+20 +Additional card for LCID1 < 0. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RFLAG +DTRT +Type +F +F +Default +0.0 +0.0 +Additional card for WITH_FAILURE keyword option. + Card 4 +Variable +Type +1 +K +F +2 +3 +GAMA1 +GAMA2 +F +F +4 +EH +F +5 +6 +7 +8 + VARIABLE +DESCRIPTION +MID +RO +E +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus. This modulus is used if the elongations are +tensile as described for the *MAT_LOW_DENSITY_FOAM. +VARIABLE +DESCRIPTION +LCID1 +Load curve or table ID: +LCID2 +HU +BETA +DAMP +GT.0: Load curve ID, see *DEFINE_CURVE, for nominal stress +versus strain for the undamaged material. +LT.0: -LCID1 is Table ID, see *DEFINE_TABLE, for nominal +stress versus strain for the undamaged material as a +function of strain rate +Load curve or table ID. The load curve ID, see *DEFINE_CURVE, +defines the nominal stress versus strain for the damaged material. +The table ID, see *DEFINE_TABLE, defines the nominal stress +versus strain for the damaged material as a function of strain rate +Hysteretic unloading factor between 0 and 1 (default = 1, i.e., no +energy dissipation), see also Figure M179-1. +β, decay constant to model creep in unloading +Viscous coefficient (.05 < recommended value <.50) to model +damping effects. +LT.0.0: |DAMP| is the load curve ID, which defines the +damping constant as a function of the maximum strain +in compression defined as: +𝜀max = max(1 − 𝜆1, 1 − 𝜆2, 1. −𝜆3). +In tension, the damping constant is set to the value corre- +sponding to the strain at 0. The abscissa should be defined +from 0 to 1. +SHAPE +Shape factor for unloading. Active for nonzero values of the +hysteretic unloading factor. Values less than one reduces the +energy dissipation and greater than one increases dissipation, see +also Figure M179-1 +FAIL +Failure option after cutoff stress is reached: +EQ.0.0: tensile stress remains at cut-off value, +EQ.1.0: tensile stress is reset to zero. +BVFLAG +Bulk viscosity activation flag, see remark below: +EQ.0.0: no bulk viscosity (recommended), +EQ.1.0: bulk viscosity active. +ED +BETA1 +KCON +*MAT_LOW_DENSITY_SYNTHETIC_FOAM +DESCRIPTION +Optional Young's relaxation modulus, 𝐸𝑑, for rate effects. See +comments below. +Optional decay constant, 𝛽1. +Stiffness coefficient for contact interface stiffness. If undefined +the maximum slope in stress vs. strain curve is used. When the +maximum slope is taken for the contact, the time step size for this +material is reduced for stability. In some cases Δt may be +significantly smaller, and defining a reasonable stiffness is +recommended. +REF +Use reference geometry to initialize the stress tensor. The +reference geometry is defined by the keyword:*INITIAL_FOAM_- +REFERENCE_GEOMETRY . +EQ.0.0: off, +EQ.1.0: on. +TC +Tension cut-off stress +RFLAG +Rate type for input: +EQ.0.0: LCID1 and LCID2 should be input as functions of true +strain rate +EQ.1.0: LCID1 and LCID2 should be input as functions of +engineering strain rate. +DTRT +Strain rate averaging flag: +EQ.0.0: use weighted running average +LT.0.0: average the last 11 values +GT.0.0: average over the last DTRT time units. +K +Material failure parameter that controls the volume enclosed by +the failure surface. +LE.0.0: ignore failure criterion; +GT.0.0: use actual K value for failure criterions. +GAMA1 +Material failure parameter, see equations below and Figure +M181-1. +GAMA2 +Material failure parameter, see equations below. +Loading curve +for first cycle +Loading curve for second +and subsequent cycles +Strain +Figure M179-1. Loading and reloading curves. + VARIABLE +DESCRIPTION +EH +Damage parameter. +Remarks: +This model is based on *MAT_LOW_DENSITY_FOAM. The uniaxial response is +shown below with a large shape factor and small hysteretic factor. If the shape factor is +not used, the unloading will occur on the loading curve for the second and subsequent +cycles. +The damage is defined as the ratio of the current volume strain to the maximum volume +strain, and it is used to interpolate between the responses defined by LCID1 and LCID2. +HU defines a hysteretic scale factor that is applied to the stress interpolated from LCID1 +and LCID2, +𝜎 = [HU + (1 − HU) × min (1, +𝑒int +max) +𝑒int +] 𝜎(LCID1,LCID2) +where eint is the internal energy and S is the shape factor. Setting HU to 1 results in a +scale factor of 1. Setting HU close to zero scales the stress by the ratio of the internal +energy to the maximum internal energy raised to the power S, resulting in the stress +being reduced when the strain is low. +*MAT_SIMPLIFIED_RUBBER/FOAM_{OPTION} +This is Material Type 181. This material model provides a rubber and foam model +defined by a single uniaxial load curve or by a family of uniaxial curves at discrete +strain rates. The definition of hysteretic unloading is optional and can be realized via a +single uniaxial unloading curve or a two-parameter formulation (starting with 971 +release R5). The foam formulation is triggered by defining a Poisson’s ratio. This +material may be used with both shell and solid elements. +Available options include: + +WITH_FAILURE +LOG_LOG_INTERPOLATION +When the WITH_FAILURE keyword option is active, a strain based failure surface is +defined suitable for incompressible polymers modeling failure in both tension and +compression. +This material +collaboration with Paul Du Bois, LSTC, and Prof. Dave J. Benson, UCSD. +law has been developed at DaimlerChrysler, Sindelfingen, +in + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +KM +F +3 +4 +MU +F +4 +5 +G +F +5 +6 +7 +8 +SIGF +REF +PRTEN +F +6 +F +7 +F +8 +Variable +SGL +SW +ST +LC /TBID TENSION +RTYPE +AVGOPT PR/BETA +Type +F +F +F +F +F +F +F +Additional card required for WITH_FAILURE option. Otherwise skip this card. +5 +6 +7 +8 + Card 3 +Variable +Type +1 +K +F +2 +3 +GAMA1 +GAMA2 +F +F +4 +EH +F +Optional Parameter Card. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCUNLD +HU +SHAPE +STOL +VISCO +Type +F +F +F +F +F +Optional Viscoelastic Constants Cards. Up to 12 card in format 5 may be input. A +keyword card (with a “*” in column 1) terminates this input if less than 12 cards are +used. +1 +Gi +F + Card 5 +Variable +Type +Default +2 +3 +4 +5 +6 +7 +8 +BETAi +VFLAG +F +I +0 + VARIABLE +DESCRIPTION +MID +RO +KM +MU +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Linear bulk modulus. +Damping coefficient (0.05 < recommended value < 0.50; default is +0.10). +VARIABLE +DESCRIPTION +G +SIGF +REF +PRTEN +SGL +SW +ST +LC/TBID +Shear modulus for frequency independent damping. Frequency +independent damping is based on a spring and slider in series. +The critical stress for the slider mechanism is SIGF defined below. +For the best results, the value of G should be 250-1000 times +greater than SIGF. +Limit stress for frequency independent, frictional, damping. +Use reference geometry to initialize the stress tensor. The +reference geometry is defined by the keyword:*INITIAL_FOAM_- +REFERENCE_GEOMETRY . +EQ.0.0: off, +EQ.1.0: on. +The tensile Poisson’s ratio for shells (optional). If PRTEN is zero, +PR/BETA will serve as the Poisson’s ratio for both tension and +compression in shells. If PRTEN is nonzero, PR/BETA will serve +only as the compressive Poisson’s ratio for shells. +Specimen gauge length +Specimen width +Specimen thickness +Load curve or table ID, see *DEFINE_TABLE, defining the force +versus actual change in the gauge length. If SGL, SW, and ST are +set to unity (1.0), then curve LC is also engineering stress versus +engineering strain. If the table definition is used a family of +curves are defined for discrete strain rates. The load curves +should cover the complete range of expected loading, i.e., the +smallest stretch ratio to the largest. +TENSION +Parameter that controls how the rate effects are treated. +Applicable to the table definition. +EQ.-1.0: rate effects are considered during tension and +compression loading, but not during unloading, +EQ.0.0: rate effects are considered for compressive loading +only, +EQ.1.0: rate effects are treated identically in tension and +compression. +*MAT_SIMPLIFIED_RUBBER/FOAM +DESCRIPTION +RTYPE +Strain rate type if a table is defined: +EQ.0.0: true strain rate, +EQ.1.0: engineering strain rate +AVGOPT +Averaging option determine strain rate to reduce numerical +noise. +LT.0.0: |AVGOPT| is a time window/interval over which the +strain rates are averaged. +EQ.0.0: simple average of twelve time steps, +EQ.1.0: running average of last 12 averages. +PR/BETA +If the value is specified between 0 and 0.5 exclusive, i.e., +0 < PR < 0.50 +the number defined here is taken as Poisson’s ratio. If zero, an +incompressible rubber like behavior is assumed and a default +value of 0.495 is used internally. If a Poisson’s ratio of 0.0 is +desired, input a small value for PR such as 0.001. When fully +integrated solid elements are used and when a nonzero Poisson’s +ratio is specified, a foam material is assumed and selective- +reduced integration is not used due to the compressibility. This is +true even if PR approaches 0.500. If any other value excluding +zero is defined, then BETA is taken as the absolute value of the +given number and a nearly incompressible rubber like behavior is +assumed. + An incrementally updated mean viscous stress +develops according to the equation: +𝑝𝑛+1 = 𝑝𝑛𝑒−𝛽𝛥𝑡 + 𝐾𝑚𝜀̇𝑘𝑘 ( +1 − 𝑒−𝛽𝛥𝑡 +), +where 𝛽 = |BETA| and 𝐾𝑚 = KM. The BETA parameter does not +apply to highly compressible foam materials. +K +Material failure parameter that controls the volume enclosed by +the failure surface. +LE.0.0: ignore failure criterion; +GT.0.0: use actual K value for failure criterions. +GAMA1 +Material failure parameter, see equations below and Figure 181.1. +GAMA2 +Material failure parameter, see equations below. +VARIABLE +DESCRIPTION +EH +Damage parameter. +LCUNLD +HU +SHAPE +Load curve, see *DEFINE_CURVE, defining the force versus +actual length during unloading. The unload curve should cover +exactly the same range as LC or the load curves of TBID and its +end points should have identical values, i.e., the combination of +LC and LCUNLD or the first curve of TBID and LCUNLD +describes a complete cycle of loading and unloading. See also +material *MAT_083. +Hysteretic unloading factor between 0 and 1 (default = 1., i.e. no +energy dissipation), see also material *MAT_083 and Figure +M57-1. This option is ignored if LCUNLD is used. +Shape factor for unloading. Active for nonzero values of the +hysteretic unloading factor HU. Values less than one reduces the +energy dissipation and greater than one increases dissipation, see +also material *MAT_083 and Figure M57-1. +STOL +Tolerance in stability check, see remarks. +VISCO +Viscoelasticity formulation. +EQ.0.0: purely elastic; +EQ.1.0: visco-elastic formulation. +Gi +Optional shear relaxation modulus for the ith term +BETAi +Optional decay constant if ith term +VFLAG +Flag for the viscoelasticity formulation. This appears only on the +first line defining Gi, BETAi, and VFLAG. If VFLAG = 0, the +standard viscoelasticity formulation is used (the default), and if +the +viscoelasticity +the +VFLAG = 1, +instantaneous elastic stress is used. +formulation using +1 = λ +K = 30 +2 = 1 +K = 20 +K = 1 +K = 10 +Figure M181-1. Failure surface for polymer for ۂ1 = 0 and ۂ2 = 0.02. +Remarks: +The frequency independent damping is obtained by the having a spring and slider in +series as shown in the following sketch: +The general failure criterion for polymers is proposed by Feng and Hallquist as +friction +𝑓 (𝐼1, 𝐼2, 𝐼3) = (𝐼1 − 3) + Γ1(𝐼1 − 3)2 + Γ2(𝐼2 − 3) = 𝐾 +where 𝐾 is a material parameter which controls the size enclosed by the failure surface, +and 𝐼1, 𝐼2 and 𝐼3 are the three invariants of right Cauchy-Green deformation tensor (𝐂) +2 +2 + 𝜆3 +2 + 𝜆2 +𝐼1 = C𝑖𝑖 = 𝜆1 +𝐼2 = +(C𝑖𝑖C𝑗𝑗 − C𝑖𝑗C𝑖𝑗) = 𝜆1 +2 𝜆2 +2 + 𝜆1 +2 𝜆3 +2 + 𝜆2 +2 +2 𝜆3 +𝐼3 = det(𝐂) = 𝜆1 +with 𝜆𝑖 are the stretch ratios in three principal directions. +2 𝜆2 +2 +2 𝜆3 +To avoid sudden failure and numerical difficulty, material failure, which is usually a +time point, is modeled as a process of damage growth. In this case, the two threshold +values are chosen as (1 - h)K and K, where h (also called EH) is a small number chosen +based on experimental results reflecting the range between damage initiation and +material failure. +The damage is defined as function of 𝑓 : +𝐷 = +⎧ +{{ +⎨ +{{ +⎩ +[ 1 + cos +𝜋(𝑓 − 𝐾) +] +ℎ𝐾 + if 𝑓 ≤ (1 − ℎ)𝐾 + if (1 − ℎ)𝐾 < 𝑓 < 𝐾 + if 𝑓 ≥ 𝐾 +This definition indicates that damage is first-order continuous. Under this definition, +the tangent stiffness matrix will be continuous. The reduced stress considering damage +effect is +𝑜 +𝜎𝑖𝑗 = (1 − 𝐷)𝜎𝑖𝑗 +𝑜 is the undamaged stress. It is assumed that prior to final failure, material +where 𝜎𝑖𝑗 +damage is recoverable. Once material failure occurs, damage will become permanent. +The LOG_LOG_INTERPOLATION option interpolates the strain rate effect in the table +TBID using log-log interpolation. +Bad choices of curves for the stress-strain response may lead to an unstable model, and +there is an option to check this to a certain tolerance level, see dimensionless parameter +STOL. The check is done by examining the eigenvalues of the tangent modulus at +selected stretch points and a warning message is issued if an eigenvalue is less than – +STOL × BULK, where BULK indicates the bulk modulus of the material. For STOL < 0 +the check is disabled, otherwise it should be chosen with care, a too small value may +detect instabilities that are insignificant in practice. To avoid significant instabilities it is +recommended to use smooth curves, at best the curves should be continuously +differentiable, in fact for the incompressible case, a sufficient condition for stability is +that the stress-stretch curve 𝑆(𝜆) can be written as +𝑆(𝜆) = 𝐻(𝜆) − +⎜⎛ 1 +⎟⎞ +√𝜆⎠ +⎝ +𝜆√𝜆 +where 𝐻(𝜆) is a function with 𝐻(1) = 0 and 𝐻′(𝜆) > 0. +Rate effects are taken into account through linear viscoelasticity by a convolution +integral of the form: +𝜎𝑖𝑗 = ∫ 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) +∂𝜀𝑘𝑙 +∂𝜏 +𝑑𝜏 +or in terms of the second Piola-Kirchhoff stress, {𝑆0 }, and Green's strain tensor, {𝑆RT}, +𝑆𝑖𝑗 = ∫ 𝐺𝑖𝑗𝑘𝑙(𝑡 − 𝜏) +∂𝐸𝑘𝑙 +∂𝜏 +𝑑𝜏 +where 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) and 𝐺𝑖𝑗𝑘𝑙(𝑡 − 𝜏) are the relaxation functions for the different stress +measures. This stress is added to the stress tensor determined from the strain energy +functional. +If we wish to include only simple rate effects, the relaxation function is represented by +six terms from the Prony series: +given by, +𝑔(𝑡) = 𝛼0 + ∑ 𝛼𝑚𝑒−𝛽𝑡 +𝑚=1 +𝑔(𝑡) = ∑ 𝐺𝑖𝑒−𝛽𝑖𝑡 +𝑖=1 +This model is effectively a Maxwell fluid which consists of a dampers and springs in +series. We characterize this in the input by shear moduli, 𝐺𝑖, and decay constants, 𝛽𝑖. +The viscoelastic behavior is optional and an arbitrary number of terms may be used. +For VFLAG = 1, the viscoelastic term is +𝜎𝑖𝑗 = ∫ 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) +∂𝜎𝑘𝑙 +∂𝜏 +𝑑𝜏 +𝐸 is the instantaneous stress evaluated from the internal energy functional. The +where 𝜎𝑘𝑙 +coefficients in the Prony series therefore correspond to normalized relaxation moduli +instead of elastic moduli. +The Mooney-Rivlin rubber model (model 27) is obtained by specifying n = 1. In spite of +the differences in formulations with model 27, we find that the results obtained with +this model are nearly identical with those of material 27 as long as large values of +Poisson’s ratio are used. +*MAT_SIMPLIFIED_RUBBER_WITH_DAMAGE +An available options includes: +LOG_LOG_INTERPOLATION +This is Material Type 183. This material model provides an incompressible rubber +model defined by a single uniaxial load curve for loading (or a table if rate effects are +considered) and a single uniaxial load curve for unloading. This model is similar to +*MAT_SIMPLIFIED_RUB-BER/FOAM This material may be used with both shell and +solid elements. +This material +collaboration with Paul Du Bois, LSTC, and Prof. Dave J. Benson, UCSD. +law has been developed at DaimlerChrysler, Sindelfingen, +in + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +K +F +3 +4 +MU +F +4 +5 +G +F +5 +6 +7 +8 +SIGF +F +6 +7 +8 +Variable +SGL +SW +ST +LC / TBID TENSION +RTYPE +AVGOPT +Type +F + Card 3 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +8 +Variable +LCUNLD +REF +STOL +Type +F +F +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +*MAT_SIMPLIFIED_RUBBER_WITH_DAMAGE +DESCRIPTION +K +MU +G +SIGF +SGL +SW +ST +LC/TBID +Linear bulk modulus. +Damping coefficient. +Shear modulus for frequency independent damping. Frequency +independent damping is based of a spring and slider in series. +The critical stress for the slider mechanism is SIGF defined below. +For the best results, the value of G should be 250-1000 times +greater than SIGF. +Limit stress for frequency independent, frictional, damping. +Specimen gauge length +Specimen width +Specimen thickness +Load curve or table ID, see *DEFINE_TABLE, defining the force +versus actual change in the gauge length. If SGL, SW, and ST are +set to unity (1.0), then curve LC is also engineering stress versus +engineering strain. If the table definition is used a family of +curves are defined for discrete strain rates. The load curves +should cover the complete range of expected loading, i.e., the +smallest stretch ratio to the largest. +TENSION +Parameter that controls how the rate effects are treated. +Applicable to the table definition. +EQ.-1.0: rate effects are considered during +tension and +compression loading, but not during unloading, +EQ.0.0: rate effects are considered for compressive loading +only, +EQ.1.0: rate effects are treated identically in tension and +compression. +RTYPE +Strain rate type if a table is defined: +EQ.0.0: true strain rate, +EQ.1.0: engineering strain rate +VARIABLE +AVGOPT +LCUNLD +DESCRIPTION +Averaging option determine strain rate to reduce numerical +noise. +EQ.0.0: simple average of twelve time steps, +EQ.1.0: running 12 point average. +Load curve, see *DEFINE_CURVE, defining the force versus +actual change in the gauge length during unloading. The unload +curve should cover exactly the same range as LC (or as the first +curve of table TBID) and its end points should have identical +values, i.e., the combination of LC (or as the first curve of table +TBID) and LCUNLD describes a complete cycle of loading and +unloading. +REF +Use reference geometry to initialize the stress tensor. The +reference geometry is defined by the keyword:*INITIAL_FOAM_- +REFERENCE_GEOMETRY . +EQ.0.0: off, +EQ.1.0: on. +STOL +Tolerance in stability check, see remark 2. +Remarks: +1. The LOG_LOG_INTERPOLATION option interpolates the strain rate effect in +the table TBID using log-log interpolation. +2. Bad choice of curves for the stress-strain response may lead to an unstable +model, and there is an option to check this to a certain tolerance level, see di- +mensionless parameter STOL. The check is done by examining the eigenvalues +of the tangent modulus at selected stretch points and a warning message is +issued if an eigenvalue is less than –STOL × BULK, where BULK indicates the +bulk modulus of the material. For STOL < 0 the check is disabled, otherwise it +should be chosen with care, a too small value may detect instabilities that are +insignificant in practice. To avoid significant instabilities it is recommended to +use smooth curves, at best the curves should be continuously differentiable, in +fact for the incompressible case, a sufficient condition for stability is that the +stress-stretch curve 𝑆(𝜆) can be written as +𝑆(𝜆) = 𝐻(𝜆) − +) +𝐻( 1 +√𝜆 +𝜆√𝜆 +where 𝐻(𝜆) is a function with 𝐻(1) = 0 and 𝐻′(𝜆) > 0. +*MAT_184 +This is Material Type 184. It is a simple cohesive elastic model for use with cohesive +element fomulations; see the variable ELFORM in *SECTION_SOLID and *SECTION_ +SHELL. + Card 1 +1 +2 +3 +4 +Variable +MID +RO +ROFLG +INTFAIL +Type +A8 +F +F +F +5 +ET +F +6 +7 +8 +EN +FN_FAIL +FT_FAIL +F +F +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +ROFLG +INTFAIL +ET +EN +Flag for whether density is specified per unit area or volume. +ROFLG = 0 specified density per unit volume (default), and +ROFLG = 1 specifies the density is per unit area for controlling +the mass of cohesive elements with an initial volume of zero. +The number of integration points required for the cohesive +element to be deleted. If it is zero, the element won’t be deleted +even if it satisfies the failure criterion. The value of INTFAIL may +range from 1 to 4, with 1 the recommended value. +The stiffness in the plane of the cohesive element. +The stiffness normal to the plane of the cohesive element. +FN_FAIL +The traction in the normal direction for tensile failure. +FT_FAIL +The traction in the tangential direction for shear failure. +Remarks: +This material cohesive model outputs three tractions having units of force per unit area +into the d3plot database rather than the usual six stress components. The in plane shear +traction along the 1-2 edge replaces the 𝑥-stress, the orthogonal in plane shear traction +replaces the 𝑦-stress, and the traction in the normal direction replaces the 𝑧-stress. +*MAT_COHESIVE_TH +This is Material Type 185. It is a cohesive model by Tvergaard and Hutchinson [1992] +in +for use with cohesive element +*SECTION_SOLID and *SECTION_SHELL. The implementation is based on the +description of the implementation in the Sandia National Laboratory code, Tahoe +[2003]. +the variable ELFORM +fomulations; see + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +RO +ROFLG +INTFAIL +SIGMAX +NLS +TLS +Type +A8 + Card 2 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +8 +Variable +LAMDA1 LAMDA2 +LAMDAF +STFSF +Type +F +F +F +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +ROFLG +INTFAIL +Flag for whether density is specified per unit area or volume. +ROFLG = 0 specified density per unit volume (default), and +ROFLG = 1 specifies the density is per unit area for controlling +the mass of cohesive elements with an initial volume of zero. +The number of integration points required for the cohesive +element to be deleted. If it is zero, the element won’t be deleted +even if it satisfies the failure criterion. The value of INTFAIL may +range from 1 to 4, with 1 the recommended value. +SIGMAX +Peak traction. +NLS +TLS +2-974 (EOS) +Length scale (maximum separation) in the normal direction. +( +) +t λ +max +reversible +loading/unloadin +g +λ λ +/ +fail +3 +2 +Λ Λ +1/ +fail +Λ Λ +2/ +fail +Figure M185-1. Relative displacement and trilinear traction-separation law + VARIABLE +DESCRIPTION +LAMDA1 +Scaled distance to peak traction (Λ1). +LAMDA2 +Scaled distance to beginning of softening (Λ2). +LAMDAF +Scaled distance for failure (Λfail). +STFSF +Penetration stiffness multiplier. The penetration stiffness, PS, in +terms of input parameters becomes: +PS = +STFSF × SIGMAX +NLS × (LAMDA1 +LAMDAF +) +Remarks: +In this cohesive material model, a dimensionless separation measure λ is used, which +grasps for the interaction between relative displacements in normal (δ3 - mode I) and +tangential (δ1, δ2 - mode II) directions : +𝜆 = √( +𝛿1 +TLS +) ++ ( +𝛿2 +TLS +) ++ ( +) +⟨𝛿3⟩ +NLS +where the Mc-Cauley bracket is used to distinguish between tension (δ3≥0) and +compression (δ3 < 0). NLS and TLS are critical values, representing the maximum +separations in the interface in normal and tangential direction. For stress calculation, a +trilinear traction-separation law is used, which is given by : +𝑡(𝜆) = +𝜎max +⎧ +{ +{ +{ +⎨ +{ +{ +{ +⎩ +𝜎max +𝜎max +Λ1/Λfail +1 − 𝜆 +1 − Λ2/Λfail +𝜆 < Λ1/Λfail +Λ1/Λfail < 𝜆 < Λ2/Λfail +Λ2/Λfail < 𝜆 < 1 +With these definitions, the traction drops to zero when 𝜆 = 1. Then, a potential 𝜙 is +defined as: +𝜙(𝛿1, 𝛿2, 𝛿3) = NLS × ∫ 𝑡(𝜆̅̅̅̅) + 𝑑𝜆̅̅̅̅ +Finally, tangential components (t1, t2) and normal component (t3) of the traction acting +on the interface in the fracture process zone are given by: +𝑡1,2 = +∂𝜙 +∂𝛿1,2 += +𝑡(𝜆) +𝛿1,2 +TLS +NLS +TLS +, 𝑡3 = +∂𝜙 +∂𝛿3 += +𝑡(𝜆) +𝛿3 +NLS +which in matrix notation is +NLS +TLS2 +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +NLS⎦ +In case of compression (𝛿3 < 0), penetration is avoided by: +𝑡1 +⎤ = +⎡ +𝑡2 +⎥ +⎢ +𝑡3⎦ +⎣ +NLS +TLS2 +𝑡(𝜆) +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +𝛿1 +⎤ +⎡ +𝛿2 +⎥ +⎢ +𝛿3⎦ +⎣ +𝑡3 = +STFSF × 𝜎max +NLS × Λ1/Λfail +𝛿3 +Loading and unloading follows the same path, i.e. this model is completely reversible. +This cohesive material model outputs three tractions having units of force per unit area +into the D3PLOT database rather than the usual six stress components. The in plane +shear traction t1 along the 1-2 edge replaces the x-stress, the orthogonal in plane shear +traction t2 replaces the y-stress, and the traction in the normal direction t3 replaces the z- +stress. +*MAT_186 +includes +three general +This is Material Type 186 and can be used only with cohesive element fomulations; see +the variable ELFORM in *SECTION_SOLID and *SECTION_SHELL. The material +model +interaction cohesive +formulations with arbitrary normalized traction-separation law given by a load curve +(TSLC). These three formulations are differentiated via the type of effective separation +parameter (TES). The interaction between fracture modes I and II is considered, and +irreversible conditions are enforced via a damage formulation (unloading/reloading +path pointing to/from the origin). See remarks for details. +irreversible mixed-mode + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +RO +ROFLG +INTFAIL +TES +TSLC +GIC +GIIC +Type +A8 + Card 2 +1 +Variable +XMU +Type +F + VARIABLE +MID +F +2 +T +F +F +3 +S +F +F +4 +F +5 +F +6 +F +7 +F +8 +STFSF +TSLC2 +F +F +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +ROFLG +INTFAIL +Flag for whether density is specified per unit area or volume. +ROFLG = 0 specifies density per unit volume (default), and +ROFLG = 1 specifies the density is per unit area for controlling +the mass of cohesive elements with an initial volume of zero. +Number of integration points required for a cohesive element to +be deleted. If it is zero, the element will not be deleted even if it +satisfies failure criterion. The value of INTFAIL may range from +1 to 4, with 1 the recommended value. +⁄ +𝑡max +1.0 +*MAT_COHESIVE_GENERAL +Possible shape of TSLC +𝐴TSLC +𝜆 = +𝛿F +Mode I Mode II +𝑡max +𝑇 +𝑆 +𝛿F +𝐺C +𝐺I +𝐴TSLC𝑇 +𝐺II +𝐴TSLC𝑆 +C +𝐺I +C +𝐺II +𝜆0 +1.0 +Figure M186-1. Normalized traction-separation law + VARIABLE +DESCRIPTION +TES +Type of effective separation parameter (ESP). +EQ.0.0 or 1.0: a dimensional separation measure is used. For +the interaction between mode I and II, a mixed- +mode propagation criterion + For +TES = 0.0 this is a power-law, and for TES = 1.0 +this is the Benzeggagh-Kenane law [1996]. See +remarks below. +is used. +EQ.2.0: +a dimensionless separation measure is used, +which grasps for the interaction between mode I +displacements and mode II displacements (simi- +lar to MAT_185, but with damage and general +traction-separation law). See remarks below. +Normalized traction-separation load curve ID. The curve must be +normalized in both coordinates and must contain at least three +points: (0.0, 0.0), (𝜆0, 1.0), and (1.0, 0.0), which represents the +origin, the peak and the complete failure, respectively . A platform can exist in the curve like the tri-linear TSLC +. +Fracture toughness / energy release rate 𝐺𝐼 +𝑐 for mode I +Fracture toughness / energy release rate 𝐺𝐼𝐼 +𝑐 for mode II +Exponent that appears in the power failure criterion (TES = 0.0) or +(TES = 1.0). +the +Recommended values for XMU are between 1.0 and 2.0. +Benzeggagh-Kenane +criterion +failure +TSLC +GIC +GIIC +XMU +T +Peak traction in normal direction (mode I) +VARIABLE +DESCRIPTION +S +Peak traction in tangential direction (mode II) +Penetration stiffness multiplier for compression. Factor = (1.0 + +STFSF) is used to scale the compressive stiffness, i.e. no scaling is +done with STFSF = 0.0 (recommended). +Normalized traction-separation load curve ID for Mode II. The +curve must be normalized in both coordinates and must contain +at least three points: (0.0, 0.0), (𝜆0, 1.0), and (1.0, 0.0), which +represents the origin, the peak and the complete failure, +respectively . If not specified, TSLC is used +for Mode II behavior as well. +STFSF +TSLC2 +Remarks: +All three formulations have in common that the traction-separation behavior of this +𝑐 and S for tangential mode II +𝑐 and T for normal mode I, 𝐺𝐼𝐼 +model is mainly given by 𝐺𝐼 +and an arbitrary normalized traction-separation load curve for both modes . The maximum (or failure) separations are then given by: +𝐹 = +𝛿𝐼 +𝐺𝐼 +𝐴TSLC × T + , 𝛿𝐼𝐼 +𝐹 = +𝐺𝐼𝐼 +𝐴TSLC × S +where 𝐴𝑇𝑆𝐿𝐶 is the area under the normalized traction-separation curve given with +TSLC. +If TSLC2 is defined +𝐹 = +𝛿𝐼 +𝐺𝐼 +𝐴TSLC × T + , 𝛿𝐼𝐼 +𝐹 = +𝐺𝐼𝐼 +𝐴TSLC2 × S +Where 𝐴𝑇𝑆𝐿𝐶2 is the area under the normalized traction-separation curve given with +TSLC2. +traction +3 +2 +1 +Fδ +II +II +Figure M186-2. Mixed mode traction-separation law +First and second formulation (TES = 0.0 and TES = 1.0): +For mixed-mode behavior, three different formulations are possible (where default +TES = 0.0 with XMU = 1.0 is recommended as a first try). Here, the total mixed-mode +2 , where 𝛿𝐼 = 𝛿3 is the separation in +2 + 𝛿𝐼𝐼 +relative displacement 𝛿𝑚 is defined as 𝛿𝑚 = √𝛿𝐼 +2 is the separation in tangential direction +2 + 𝛿2 +normal direction (mode I) and 𝛿𝐼𝐼 = √𝛿1 +(mode II). See Figure M186-2. The ultimate mixed-mode displacement 𝛿𝐹 (total failure) +for the power law (TES = 0.0) is: +𝛿𝐹 = +1 + 𝛽2 +⎡( +⎢ +𝐴TSLC ⎣ +𝑐) +𝐺𝐼 +XMU ++ ( +S × 𝛽2 +𝐺𝐼𝐼 +𝑐 ) +XMU +XMU +− 1 +⎤ +⎥ +⎦ +If TSLC2 is defined this changes to: +𝛿𝐹 = 1 + 𝛽2 +𝐴TSLC × T +𝐺𝐼 +⎡( +⎢ +⎣ +XMU +) ++ ( +𝐴TSLC2 × S × 𝛽2 +𝐺𝐼𝐼 +) +XMU +XMU +− 1 +⎤ +⎥ +⎦ +and alternatively for the Benzeggagh-Kenane law [1996] (TES = 1.0): +𝛿𝐹 = +1 + 𝛽2 +⎡𝐺𝐼 +⎢ +𝐴TSLC(T + S × 𝛽2) ⎣ +𝑐 + (𝐺𝐼𝐼 +𝑐 − 𝐺𝐼 +𝑐) ( +XMU +S × 𝛽2 +𝑇 + S × 𝛽2) +⎤ +⎥ +⎦ +If TSLC2 is defined this changes to: +𝛿𝐹 = +1 + 𝛽2 +𝐴TSLC × T + 𝐴TSLC2 × S × 𝛽2 +𝑐 + (𝐺𝐼𝐼 +𝑐 − 𝐺𝐼 +𝑐) ( +⎡𝐺𝐼 +⎢ +⎣ +𝐴TSLC2 × S × 𝛽2 +𝐴TSLC × 𝑇 + 𝐴TSLC2 × S × 𝛽2) +XMU +⎤ +⎥ +⎦ +where 𝛽 = 𝛿𝐼𝐼/𝛿𝐼 is the “mode mixity”. The larger the exponent XMU is chosen, the +larger the fracture toughness in mixed-mode situations will be. In this model, damage + irreversible conditions are enforced with +of the interface is considered, i.e. +loading/unloading paths coming from/pointing to the origin. This formulation is +similar to MAT_COHESIVE_MIXED_MODE (MAT_138), but with the arbitrary +traction-separation law TSLC. +Third formulation (TES = 2.0): +Here, a dimensionless effective separation parameter 𝜆 is used, which grasps for the +interaction between relative displacements in normal (𝛿3 - mode I) and tangential (𝛿1,𝛿2 +- mode II) directions: +𝜆 = +√ +√√ +⎷ + ( +𝛿1 +𝐹 ) +𝛿𝐼𝐼 ++ ( +𝛿2 +𝐹 ) +𝛿𝐼𝐼 ++ ⟨ +𝛿3 +𝐹⟩ +𝛿𝐼 +𝐹 and 𝛿𝐼𝐼 +where the Mc-Cauley bracket is used to distinguish between tension (𝛿3 ≥ 0) and +𝐹 are critical values, representing the maximum +compression (𝛿3 < 0). 𝛿𝐼 +separations in the interface in normal and tangential direction . For stress calculation, +the normalized traction-separation load curve TSLC is used: 𝑡 = 𝑡max × 𝑡 ̅(𝜆). This +formulation is similar to MAT_COHESIVE_TH (MAT_185), but with the arbitrary +traction-separation law and a damage formulation (i.e. irreversible conditions are +enforced with loading/unloading paths coming from/pointing to the orig +*MAT_SAMP-1 +Purpose: This is Material Type 187 (Semi-Analytical Model for Polymers). This material +model uses an isotropic C-1 smooth yield surface for the description of non-reinforced +plastics. Details of the implementation are given in [Kolling, Haufe, Feucht and Du Bois +2005]. +This material +collaboration with Paul Du Bois and Dynamore, Stuttgart. +law has been developed at DaimlerChrysler, Sindelfingen, +in + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +4 +5 +6 +7 +8 +BULK +GMOD +EMOD +NUE +RBCFAC NUMINT +F +3 +F +4 +F +5 +F +6 +F +7 +8 +Variable +LCID-T +LCID-C +LCID-S +LCID-B +NUEP +LCID-P +INCDAM +Type +I + Card 3 +1 +I +2 +I +3 +I +4 +F +5 +I +6 +7 +8 +Variable +LCID-D +EPFAIL +DEPRPT LCID_TRI +LCID_LC +Type +I + Card 4 +1 +F +2 +F +3 +I +4 +I +5 +6 +7 +8 +Variable +MITER +MIPS +INCFAIL +ICONV +ASAF +Type +I +I +I +I +*MAT_SAMP-1 +Optional Card. +*MAT_187 + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCEMOD +BETA +FILT +Type +F +F +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +BULK +Bulk modulus, used by LS-DYNA in the time step calculation +GMOD +Shear modulus, used by LS-DYNA in the time step calculation +EMOD +Young’s modulus +NUE +Poisson ratio +qs +t +qbt +linear +extrapolation +qc +qbc +rbcfac > +1 +rbcfac = 1 +rbcfac < 1 +rbcfac = 0.5 +(lower bound) +von Mises stress +pressure +required +input +optional +input +biaxial tension +bt +tension +t +shear +s +compression +c +bc biaxial compression +q +p +data +data +rbcfac = +qbc +qc +extrapolated data +Figure M187-1. von Mises stress as a function of pressure + VARIABLE +RBCFAC +DESCRIPTION +Ratio of yield in biaxial compression vs. yield in uniaxial +compression. If RBCFAC is nonzero and all four curves LCID-T, +LCID-C, LCID-S, and LCID-B are defined, a piecewise-linear +yield surface as shown in Figure M187-1 is activated. See Remark +3. Default is 0. +NUMINT +Number of integration points which must fail before the element +is deleted. This option is available for shells and solids. +LT.0.0: |NUMINT| is percentage of integration points/layers +which must fail before shell element fails. For fully in- +tegrated shells, a methodology is used where a layer +fails if one integration point fails and then the given +percentage of layers must fail before the element fails. +Only available for shells. +*MAT_SAMP-1 + VARIABLE +LCID-T +LCID-C +LCID-S +LCID-B +NUEP +LCID-P +*MAT_187 +DESCRIPTION +Load curve or table ID giving the yield stress as a function of +plastic strain, these curves should be obtained from quasi-static +and (optionally) dynamic uniaxial tensile tests, this input is +mandatory and the material model will not work unless at least +one tensile stress-strain curve is given. If LCID-T is a table ID, the +table values are plastic strain rates, and a curve of yield stress +versus plastic strain must be given for each of those strain rates. +If the first value in the table is negative, LS-DYNA assumes that +all the table values represent the natural logarithm of plastic +strain rate. When the highest plastic strain rate is several orders of +magnitude greater than the lowest strain rate, it is recommended +that the natural log of plastic strain rate be input in the table. See +Remark 4. +Load curve ID giving the yield stress as a function of plastic +strain, this curve should be obtained from a quasi-static uniaxial +compression test, this input is optional. +Load curve ID giving the yield stress as a function of plastic +strain, this curve should be obtained from a quasi-static shear test, +this input is optional. +Load curve ID giving the yield stress as a function of plastic +strain, this curve should be obtained from a quasi-static biaxial +tensile test, this input is optional. +Plastic Poisson’s ratio: an estimated ratio of transversal to +longitudinal plastic rate of deformation under uniaxial loading +should be given. +Load curve ID giving the plastic Poisson's ratio as a function of +plastic strain during uniaxial tensile and uniaxial compressive +testing. The plastic strain on the abscissa is negative for +compression and positive for tension. It is important to cover +both tension and compression. If LCID-P is given, the constant +value of plastic Poisson's ratio NUEP is ignored. +INCDAM +Flag to control the damage evolution as a function of triaxiality. +EQ.0: damage evolution is independent of the triaxialty. +EQ.1: an incremental formulation is used to compute the +damage. +LCID-D +EPFAIL +DEPRPT +LCID_TRI +LCID_LC +MITER +MIPS +*MAT_SAMP-1 +DESCRIPTION +Load curve ID giving the damage parameter as a function of +equivalent plastic strain during uniaxial tensile testing. By +default this option assumes that effective (i.e. undamaged) yield +values are used in the load curves LCID-T, LCID-C, LCID-S and +LCID-B. If LCID-D is given a negative value, true (i.e. damaged) +yield stress values can be used. In this case an automatic stress- +strain recalibration (ASSR) algorithm is activated. The damage +value must be defined in the range 0 ≤ 𝑑 < 1. If EPFAIL and +DEPRPT are given, the curve is used only until the effective +plastic strain reaches EPFAIL. +This parameter is the equivalent plastic strain at failure. If +EPFAIL is given as a negative integer, a load curve is expected +that defines EPFAIL as a function of the plastic strain rate. +Default value is 105. +Increment of equivalent plastic strain between failure point and +rupture point. Stresses will fade out to zero between EPFAIL and +EPFAIL+DEPRPT. If DEPRPT is given a negative value a curve +definition is expected where DEPRPT is defined as function of the +triaxiality. +Load curve that specifies a factor that works multiplicatively on +the value of EPFAIL depending on +(i.e. +pressure/sigma_vm). For a triaxiality of -1/3 a value of 1.0 +should be specified. +triaxiality +the +Load curve that specifies a factor that works multiplicatively on +the value of EPFAIL depending on a characteristic element +length, defined as the average length of spatial diagonals. +Maximum number of iterations in the cutting plane algorithm, +default is set to 400 +Maximum number of iterations in the secant iteration performed +to enforce plane stress (shell elements only), default set to 10 +INCFAIL +Flag to control the failure evolution as a function of triaxiality. +EQ.0: Failure evolution is independent of the triaxiality. +EQ.1: Incremental formulation is used to compute the failure +value. +EQ.-1: the failure model is deactivated. +*MAT_SAMP-1 +LCID_C = 0 +⎫ +}} +LCID_S = 0 +⎬ +}} +LCID_B = 0⎭ +⇒ +⎧𝜎𝑐 = 𝜎𝑡 +{{{ +⎨ +{{{ +⎩ +𝜎𝑠 = +𝜎𝑡 +√3 +LCID_C = 0 +⎫ +}} +LCID_S ≠ 0 +⎬ +}} +LCID_B = 0⎭ +LCID_C ≠ 0 +⎫ +}} +LCID_S = 0 +⎬ +}} +LCID_B = 0⎭ +⇒ 𝜎c = +√3𝜎𝑡𝜎𝑠 +2𝜎𝑡 − √3𝜎𝑠 +⇒ 𝜎𝑠 = +2𝜎c𝜎𝑡 +√3(𝜎𝑡 + 𝜎𝑐) +LCID_C = 0 +⎫ +}} +LCID_S = 0 +⎬ +}} +LCID_B ≠ 0⎭ +⇒ +⎧𝜎𝑐 = +{{ +⎨ +{{ +⎩ +𝜎𝑠 = +𝜎𝑡𝜎𝑏 +3𝜎𝑏 − 2𝜎𝑡 +𝜎𝑡𝜎𝑏 +√3(2𝜎𝑏 − 𝜎𝑡) +*MAT_187 +𝜎vM +von Misses cylinder +𝜎vM +Drucker-Prager Cone +⎫ +}}} +⎬ +}}} +⎭ +⎫ +} +} +} +} +} +} +} +} +} +} +} +} +⎬ +} +} +} +} +} +} +} +} +} +} +} +} +⎭ +Figure M187-2. Fewer than 3 load curves + VARIABLE +DESCRIPTION +ICONV +Formulation flag: +EQ.0: default +EQ.1: yield surface is internally modified by increasing the +shear yield until a convex yield surface is achieved. +ASAF +Safety factor, used only if ICONV = 1, values between 1 and 2 can +improve convergence, however the shear yield will be artificially +increased if this option is used, default is set to 1. +LCEMOD +Load curve ID defining Young’s modulus as function of effective +strain rate. +BETA +FILT +Decay constant in viscoelastic law: 𝜎̇ (𝑡) = −β ∙ 𝜎(𝑡) + 𝐸(𝜀̇(𝑡)) ∙ +𝜀̇(𝑡) +Factor for strain rate filtering: 𝜀̇𝑛+1 +𝑎𝑣𝑔 +𝜀̇𝑛 +𝑎𝑣𝑔 = (1 − FILT) ∙ 𝜀̇𝑛+1 +𝑐𝑢𝑟𝑟 + FILT ∙ +LCID_C ≠ 0 +LCID_S ≠ 0 +⎫ +}} +⎬ +}} +LCID_B = 0⎭ +⇒ normal SAMP-1 behavior +LCID_C ≠ 0 +LCID_S = 0 +⎫ +}} +⎬ +}} +LCID_B ≠ 0⎭ +⇒ 𝜎𝑠 = +√3 +√ +3𝜎𝑏 +2𝜎𝑐𝜎𝑡 +(2𝜎𝑏 + 𝜎𝑐)(2𝜎𝑏 − 𝜎𝑡) +LCID_C = 0 +LCID_S ≠ 0 +⎫ +}} +⎬ +}} +LCID_B ≠ 0⎭ +⇒ 𝜎𝑐 = +6(162𝜎𝑏 +2𝜎𝑠 +2 + 323𝜎𝑏 +2 + 𝜎𝑏𝜎𝑠 +2𝜎𝑡) +2𝜎𝑡 + 3𝜎𝑠 +6𝜎𝑏𝜎𝑠 +2𝜎𝑡 +LCID_C ≠ 0 +LCID_S ≠ 0 +⎫ +}} +⎬ +}} +LCID_B ≠ 0⎭ +⇒ overspecified, least square +⎫ +} +} +} +} +} +} +} +} +} +} +} +} +} +} +} +} +⎬ +} +} +} +} +} +} +} +} +} +} +} +} +} +} +} +} +⎭ +𝜎vM +SAMP-1 yield surface defined +through load curves +Figure M187-3. Three or more load curves +Load curves: +Material SAMP-1 uses three yield curves internally to evaluate a quadratic yield +surface. *MAT_SAMP-1 accepts four different kinds of yield curves, LCID_T, LCID_C, +LCID_S, and LCID_B where data from tension tests (LCID_T) is always required, but +the others are optional. If fewer than three curves are defined, as indicated by setting +the missing load curve IDs to 0, the remaining curves are generated internally. +1. Fewer than 3 load curves. In the case of fewer than 3 load curves, a linear +yield surface in the invariant space spanned by the pressure and the von Mises +stress is generated using the available data. See figure M187-2. +2. Three or more load curves. See figure M187-3. +Remarks: +1. Damage. If the LCID_D is given, then a damage curve as a function of +equivalent plastic strains acting on the stresses is defined as shown in Figure +M187-4. +𝑑 +1.0 +𝑑𝑐 +𝜀fail +𝜀erode +𝜀𝑝 +𝑝 +(cid:1526)𝜀rpt +Figure M187-4. EPFAIL and DEPRPT defined the failure and fading behavior +of a single element. +Since the damaging curve acts on the yield values, the inelastic results are ef- +fected by the damage curve. As a means to circumvent this, the load curve +LCID-D may be given a negative ID. This will lead to an internal conversion of +from nominal to effective stresses (ASSR). +2. Unsolvable Yield Surface Case. Since the generality of arbitrary curve inputs +allows unsolvable yield surfaces, SAMP may modify curves internally. This +will always lead to warning messages at the beginning of the simulation run. +One modification that is not allowed are negative tangents of the last two data +points of any of the yield curves. +3. RBCFAC. If RBCFAC is nonzero and curves LCID-T, LCID-C, LCID-S, and +LCID-B are specified, the yield surface in 𝐼1-𝜎𝑣𝑚 -stress space is constructed +such that a piecewise-linear yield surface is activated. This option can help +promote convergence of the plasticity algorithm. Figure M187-1 illustrates the +effect of RBCFAC on behavior in biaxial compression. +4. Dynamic Amplification Factor for Yield Stress. If LCID-T is given as a table +specifying strain-rate scaling of the yield stress, then the compressive, shear and +biaxial yield stresses are computed by multiplying their respective static values +by dynamic amplification factor (dynamic/static ratio) of the tensile yield +stress. +*MAT_SAMP-1 +# +2 +3 +4 +5 +6 +Interpretation +plastic strain in tension/compression +plastic strain in shear +biaxial plastic strain +damage +volumetric plastic strain +16 plastic strain rate in tension/compression +17 plastic strain rate in shear +18 +biaxial plastic strain rate +*MAT_THERMO_ELASTO_VISCOPLASTIC_CREEP +This is Material Type 188. In this model, creep is described separately from plasticity +using Garafalo’s steady-state hyperbolic sine creep law or Norton’s power law. Viscous +effects of plastic strain rate are considered using the Cowper-Symonds model. Young’s +modulus, Poisson’s ratio, thermal expansion coefficient, yield stress, material +parameters of Cowper-Symonds model as well as the isotropic and kinematic +hardening parameters are all assumed to be temperature dependent. Application scope +includes: simulation of solder joints in electronic packaging, modeling of tube brazing +process, creep age forming, etc. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +E +F +3 +4 +PR +F +4 +5 +6 +7 +8 +SIGY +ALPHA +LCSS +REFTEM +F +5 +F +6 +F +7 +F +8 +Variable +QR1 +CR1 +QR2 +CR2 +QX1 +CX1 +QX2 +CX2 +Type +F + Card 3 +Variable +Type +1 +C +F + Card 4 +1 +F +2 +P +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +LCE +LCPR +LCSIGY +LCQR +LCQX +LCALPH +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +LCC +LCP +LCCR +LCCX +CRPA +CRPB +CRPQ +CRPM +Type +F +F +F +F +F +F +F +*MAT_THERMO_ELASTO_VISCOPLASTIC_CREEP + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CRPLAW +Type +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus +Poisson’s ratio +SIGY +Initial yield stress +ALPHA +Thermal expansion coefficient +LCSS +Load curve ID or Table ID. The load curve ID defines effective +stress versus effective plastic strain. The table ID defines for each +temperature value a load curve ID giving the stress versus +effective plastic strain for that temperature. The stress versus +effective plastic strain curve for the lowest value of temperature is +used if the temperature falls below the minimum value. +Likewise, the stress versus effective plastic strain curve for the +highest value of temperature is used if the temperature exceeds +the maximum value. Card 2 is ignored with this option. +REFTEM +Reference temperature that defines thermal expansion coefficient +QR1 +CR1 +QR2 +CR2 +QX1 +CX1 +Isotropic hardening parameter 𝑄𝑟1 +Isotropic hardening parameter 𝐶𝑟1 +Isotropic hardening parameter 𝑄𝑟2 +Isotropic hardening parameter 𝐶𝑟2 +Kinematic hardening parameter 𝑄𝜒1 +Kinematic hardening parameter 𝐶𝜒1 +VARIABLE +DESCRIPTION +QX2 +CX2 +C +P +LCE +Kinematic hardening parameter 𝑄𝜒2 +Kinematic hardening parameter 𝐶𝜒2 +Viscous material parameter 𝐶 +Viscous material parameter 𝑃 +Load curve for scaling Young's modulus as a function of +temperature +LCPR +Load curve for scaling Poisson's ratio as a function of temperature +LCSIGY +LCQR +LCQX +LCALPH +LCC +LCP +LCCR +LCCX +Load curve for scaling initial yield stress as a function of +temperature +Load curve for scaling the isotropic hardening parameters QR1 +and QR2 or the stress given by the load curve LCSS as a function +of temperature +Load curve for scaling the kinematic hardening parameters QX1 +and QX2 as a function of temperature +Load curve for scaling the thermal expansion coefficient as a +function of temperature +Load curve for scaling the viscous material parameter 𝐶 as a +function of temperature +Load curve for scaling the viscous material parameter 𝑃 as a +function of temperature +Load curve for scaling the isotropic hardening parameters CR1 +and CR2 as a function of temperature +Load curve for scaling the kinematic hardening parameters CX1 +and CX2 as a function of temperature +CRPA +Creep law parameter 𝐴 +GT.0.0: Constant value +LT.0.0: Load curve ID = (-CRPA) which defines 𝐴 as a function +of temperature, 𝐴(𝑇). +*MAT_THERMO_ELASTO_VISCOPLASTIC_CREEP +DESCRIPTION +CRPB +Creep law parameter 𝐵 +GT.0.0: Constant value +LT.0.0: Load curve ID = (-CRPB) which defines 𝐵 as a function +of temperature, 𝐵(𝑇). +CRPQ +Creep law parameter 𝑄 = 𝐸/𝑅 where E is the activation energy +and R is the universal gas constant. +GT.0.0: Constant value +LT.0.0: Load curve ID = (-CRPQ) which defines 𝑄 as a function +of temperature, 𝑄(𝑇). +CRPM +Creep law parameter m +GT.0.0: Constant value +LT.0.0: Load curve ID = (-CRPM) which defines m as a +function of temperature, 𝑚(𝑇). +CRPLAW +Creep law definition : +EQ.0.0: Garofalo’s hyperbolic sine law (default). +EQ.1.0: Norton’s power law. +Remarks: +If LCSS is not given any value the uniaxial stress-strain curve has the form +𝑝 )] +𝑝 )] + 𝑄𝑟2[1 − exp(−𝐶𝑟2𝜀eff +𝑝 )] + 𝑄𝜒2[1 − exp(−𝐶𝜒2𝜀eff +𝑝 ) = 𝜎0 + 𝑄𝑟1[1 − exp(−𝐶𝑟1𝜀eff ++ 𝑄𝜒1[1 − exp(−𝐶𝜒1𝜀eff +𝜎(𝜀eff +𝑝 )]. +Viscous effects are accounted for using the Cowper-Symonds model, which scales the +yield stress with the factor: +𝜀̇eff +⎟⎞ +𝐶 ⎠ +For CRPLAW = 0, the steady-state creep strain rate of Garafalo’s hyperbolic sine +equation is given by +⎜⎛ +⎝ +1 + +. +𝑝⁄ +𝜀̇𝑐 = 𝐴[sinh(𝐵𝜏𝑒)]𝑚exp (− +). +For CRPLAW = 1, the steady-state creep strain rate is given by Norton’s power law +equation: +𝜀̇𝑐 = 𝐴(𝜏𝑒)𝐵𝑡𝑚. +In the above, 𝜏𝑒 is the effective elastic stress in the von Mises sense, T is the temperature +and t is the time. The following is a schematic overview of the resulting stress update. +The multiaxial creep strain increment is given by +Δ𝜀𝑐 = Δ𝜀𝑐 3𝝉 𝑒 +2𝜏𝑒 +where 𝛕𝑒 is the elastic deviatoric stress tensor. Similarily the plastic and thermal strain +increments are given by +Δ𝜺p = Δ𝜀𝑝 3𝝉 𝑒 +2𝜏𝑒 +𝑇 +Δ𝜺𝑇 = 𝛼𝑡+Δ𝑡(𝑇 − 𝑇ref)𝑰 − 𝜺𝑡 +where α is the thermal expansion coefficient (note the definition compared to that of +other materials). Adding it all together, the stress update is given by +𝝈𝑡+Δ𝑡 = 𝑪𝑡+Δ𝑡(𝜺𝑡 +𝑒 + Δ𝜺 − Δ𝜺𝑝 − Δ𝜺𝑐 − Δ𝜺𝑇) +The plasticity is isotropic or kinematic but with a von Mises yield criterion, the +subscript in the equation above indicates the simulation time of evaluation. Internally, +this stress update requires the solution of a nonlinear equation in the effective stress, the +viscoelastic strain increment and potentially the plastic strain increment. +*MAT_ANISOTROPIC_THERMOELASTIC +This is Material Type 189. This model characterizes elastic materials whose elastic +properties are temperature-dependent. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +4 +5 +6 +7 +8 +TA1 +TA2 +TA3 +TA4 +TA5 +TA6 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +C11 +C12 +C13 +C14 +C15 +C16 +C22 +C23 +Type +F + Card 3 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +C24 +C25 +C26 +C33 +C34 +C35 +C36 +C44 +Type +F + Card 4 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +C45 +C46 +C55 +C56 +C66 +TGE +TREF +AOPT +Type +F +F +F +F +F +F + Card 5 +Variable +1 +XP +Type +F +2 +YP +F +3 +ZP +F +4 +A1 +F +5 +A2 +F +6 +A3 +F +F +8 +F +7 +MACF +Card 6 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +BETA +REF +F +F + VARIABLE +DESCRIPTION +MID +RO +TAi +CIJ +TGE +TREF +AOPT +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Curve IDs defining the coefficients of thermal expansion for the +six components of strain tensor as function of temperature. +Curve IDs defining the 6×6 symmetric constitutive matrix in +material coordinate system as function of temperature. Note that +1 corresponds to the a material direction, 2 to the b material +direction, and 3 to the c material direction. +Curve ID defining the structural damping coefficient as function +of temperature. +Reference temperature for the calculation of thermal loads or the +definition of thermal expansion coefficients. +Material +TIC/MAT_002 for a complete description.) +option, +axes +(see MAT_ANISOTROPIC_ELAS- +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the a-direction. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +*MAT_ANISOTROPIC_THERMOELASTIC +DESCRIPTION +element normal. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector v, and +an originating point, P, which define the centerline ax- +is. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +XP, YP, ZP +XP, YP, ZP define coordinates of point p for AOPT = 1 and 4. +A1, A2, A3 +a1, a2, a3 define components of vector a for AOPT = 2. +MACF +Material axis change flag for brick elements +D1, D2, D3 +d1, d2, d3 define components of vector d for AOPT = 2. +V1, V2, V3 +v1, v2, v3 define components of vector v for AOPT = 3 and 4. +BETA +REF +Material angle in degrees for AOPT = 3, may be overwritten on +the element card, see *ELEMENT_SOLID_ORTHO. +Use initial geometry to initialize the stress tensor +*MAT_FLD_3-PARAMETER_BARLAT +This is Material Type 190. This model was developed by Barlat and Lian [1989] for +modeling sheets with anisotropic materials under plane stress conditions. This material +allows the use of the Lankford parameters for the definition of the anisotropy. This +particular development is due to Barlat and Lian [1989]. It has been modified to include +a failure criterion based on the Forming Limit Diagram. The curve can be input as a +load curve, or calculated based on the n-value and sheet thickness. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +Variable +Type +1 +M +F + Card 3 +1 +Variable +AOPT +Type +F + Card 4 +1 +Variable +Type +2 +RO +F +2 +3 +E +F +3 +4 +PR +F +4 +5 +HR +F +5 +R00 +R45 +R90 +LCID +F +4 +I +5 +6 +P1 +F +6 +E0 +F +6 +7 +P2 +F +7 +SPI +F +7 +8 +ITER +F +8 +P3 +F +8 +FLDCID +RN +RT +FLDSAFE FLDNIPF +F +7 +F +8 +I +F +F +4 +A1 +F +5 +A2 +F +6 +A3 +F +F +2 +C +F +2 +F +3 +P +F +Variable +1 +V1 +Type +F +*MAT_FLD_3-PARAMETER_BARLAT +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +BETA +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +HR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s modulus, 𝐸 +Poisson’s ratio, 𝜈 +Hardening rule: +EQ.1.0: linear (default) +EQ.2.0: exponential (Swift) +EQ.3.0: load curve +EQ.4.0: exponential (Voce) +EQ.5.0: exponential (Gosh) +EQ.6.0: exponential (Hocket-Sherby) +P1 +Material parameter: +HR.EQ.1.0: Tangent modulus +HR.EQ.2.0: 𝑘, strength coefficient +for Swift exponential +hardening +HR.EQ.4.0: 𝑎, coefficient for Voce exponential hardening +HR.EQ.5.0: 𝑘, strength coefficient +for Gosh exponential +hardening +HR.EQ.6.0: 𝑎, +coefficient +for Hocket-Sherby exponential +hardening +VARIABLE +DESCRIPTION +P2 +Material parameter: +HR.EQ.1.0: Yield stress +HR.EQ.2.0: 𝑛, exponent for Swift exponential hardening +HR.EQ.4.0: 𝑐, coefficient for Voce exponential hardening +HR.EQ.5.0: 𝑛, exponent for Gosh exponential hardening +HR.EQ.6.0: 𝑐, +coefficient +for Hocket-Sherby exponential +hardening +ITER +Iteration flag for speed: +ITER.EQ.0.0: fully iterative +ITER.EQ.1.0: fixed at three iterations +Generally, ITER = 0 is recommended. However, ITER = 1 is +somewhat faster and may give acceptable results in most +problems. +M +R00 +R45 +R90 +LCID +E0 +m, exponent in Barlat’s yield surface +𝑅00, Lankford parameter determined from experiments +𝑅45, Lankford parameter determined from experiments +𝑅90, Lankford parameter determined from experiments +load curve ID for the load curve hardening rule +Material parameter +HR.EQ.2.0: 𝜀0 for determining initial yield stress for Swift +exponential hardening. (Default = 0.0) +HR.EQ.4.0: 𝑏, coefficient for Voce exponential hardening +HR.EQ.5.0: 𝜀0 for determining initial yield stress for Gosh +exponential hardening. (Default = 0.0) +HR.EQ.6.0: 𝑏, +coefficient +for Hocket-Sherby exponential +hardening +*MAT_FLD_3-PARAMETER_BARLAT +DESCRIPTION +SPI +If 𝜀0 is zero above and HR.EQ.2.0. (Default = 0.0) +EQ.0.0: 𝜀0 = +⁄ +(𝑛−1) +⎜⎜⎜⎛𝐸 +𝑘⁄ +⎝ +⎟⎟⎟⎞ +⎠ +LE.0.2: 𝜀0 = SPI +GT.0.2: 𝜀0 = +𝑛⁄ +⎜⎜⎜⎛SPI +⁄ +⎝ +⎟⎟⎟⎞ +⎠ +P3 +Material parameter: +HR.EQ.5.0: 𝑝, parameter for Gosh exponential hardening +HR.EQ.6.0: 𝑛, +exponent +for Hocket-Sherby +exponential +hardening +AOPT +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the shell ele- +ment normal by the angle BETA. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +C +P +𝐶 in Cowper-Symonds strain rate model +𝑝 in Cowper-Symonds strain rate model, 𝑝 = 0.0 for no strain rate +effects +VARIABLE +FLDCID +RN +RT +DESCRIPTION +Load curve ID defining the Forming Limit Diagram. Minor +engineering strains in percent are defined as abscissa values and +Major engineering strains in percent are defined as ordinate +values. The forming limit diagram is shown in Figure M39-1. In +defining the curve list pairs of minor and major strains starting +with the left most point and ending with the right most point, see +*DEFINE_CURVE. +Hardening exponent equivalent to the n-value in a power law +hardening law. If the parameter FLDCID is not defined, this +value in combination with the value RT can be used to calculate a +forming limit curve to allow for failure. +Sheet thickness used for calculating a forming limit curve. This +value does not override the sheet thickness in any way. It is only +used in conjunction with the parameter RN to calculate a forming +limit curve if the parameter FLDCID is not defined. +FLDSAFE +A safety offset of the forming limit curve. This value should be +input as a percentage (ex. 10 not 0.10). This safety margin will be +applied to the forming limit curve defined by FLDCID or the +curve calculated by RN and RT. +FLDNIPF +Numerical integration points failure treatment. +GT.0.0: The number of element integration points that must fail +before the element is deleted. By default, if one inte- +gration point has strains above the forming limit curve, +the element is flagged for deletion. +LT.0.0: The element is deleted when all integration points +within a relative distance of –FLDNIPF from the mid +surface have failed (value between -1.0 and 0.0). +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3. +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2. +BETA +Material angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA. +See material 36 for the theoretical basis. +*MAT_FLD_3-PARAMETER_BARLAT +The forming limit curve can be input directly as a curve by specifying a load curve id +with the parameter FLDCID. When defining such a curve, the major and minor strains +must be input as percentages. +Alternatively, the parameters RN and RT can be used to calculate a forming limit curve. +The use of RN and RT is not recommended for non-ferrous materials. RN and RT are +ignored if a non-zero FLDCID is defined. +The first history variable is the maximum strain ratio defined by: +𝜀majorworkpiece +𝜀majorfld +corresponding to 𝜀minorworkpiece. A value between 0 and 1 indicates that the strains lie +below the forming limit curve. Values above 1 indicate that the strains are above the +forming limit curve. +*MAT_191 +Purpose: This is Material Type 191. This material enables lumped plasticity to be +developed at the ‘node 2’ end of Belytschko-Schwer beams (resultant formulation). The +plastic yield surface allows interaction between the two moments and the axial force. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +F +F +4 +5 +6 +7 +8 +PR +ASFLAG +FTYPE +DEGRAD +IFEMA +Default +none +none +none +none +0.0 + Card 2 +1 +2 +3 +4 +5 +I +1 +6 +I +0 +7 +I +0 +8 +Variable +LCPMS +SFS +LCPMT +SFT +LCAT +SFAT +LCAC +SFAC +Type +F +F +F +F +F +F +F +F +Default +none +1.0 +LCMPS +1.0 +none +1.0 +LCAT +1.0 +This card 3 format is used when FTYPE = 1 (default). + Card 3 +1 +2 +3 +4 +Variable +ALPHA +BETA +GAMMA +DELTA +Type +F +F +F +F +5 +A +F +6 +B +F +7 +8 +FOFFS +F +Default see note see note see note see note see note see note +0.0 +This card 3 format is used when FTYPE = 2. + Card 3 +1 +Variable +SIGY +Type +F +2 +D +F +3 +W +F +4 +TF +F +5 +TW +F +Default +none +none +none +none +none +6 +7 +8 +This card 3 format is used when FTYPE = 4. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PHI_T +PHI_C +PHI_B +Type +F +F +F +Default +0.8 +0.85 +0.9 +This card 3 format is used when FTYPE = 5. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ALPHA +BETA +GAMMA +DELTA +PHI_T +PHI_C +PHI_B +Type +F +F +F +F +F +F +F +Default +none +none +1.4 +none +1.0 +1.0 +1.0 +FEMA limits Card 1. Additional card for IFEMA > 0. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PR1 +PR2 +PR3 +PR4 +Type +Default +F +0 +F +0 +F +0 +F +0 +FEMA limits Card 2. Additional card for IFEMA = 2. + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TS1 +TS2 +TS3 +TS4 +CS1 +CS2 +CS3 +CS4 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +F +F +F +TS1 +TS2 +TS3 +TS4 + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +ASFLAG +Axial strain definition for force-strain curves, degradation and +FEMA output: +EQ.0.0: true (log) total strain +EQ.1.0: change in length +EQ.2.0: nominal total strain +EQ.3.0: FEMA plastic strain ( = nominal total strain minus +elastic strain) +*MAT_SEISMIC_BEAM +DESCRIPTION +FTYPE +Formulation type for interaction +EQ.1: Parabolic coefficients, axial load and biaxial bending +(default). +EQ.2: Japanese code, axial force and major axis bending. +EQ.4: AISC utilization calculation but no yielding +EQ.5: AS4100 utilization calculation but no yielding +DEGRADE +Flag for degrading moment behavior +EQ.0: Behavior as in previous versions +EQ.1: Fatigue-type degrading moment-rotation behavior +EQ.2: FEMA-type degrading moment-rotation behavior +IFEMA +Flag for input of FEMA thresholds +EQ.0: No input +EQ.1: Input of rotation thresholds only +EQ.2: Input of rotation and axial strain thresholds +LCPMS +Load curve ID giving plastic moment vs. Plastic rotation at node +2 about local s-axis. See *DEFINE_CURVE. +SFS +Scale factor on s-moment at node 2. +LCPMT +Load curve ID giving plastic moment vs. Plastic rotation at node +2 about local t-axis. See *DEFINE_CURVE. +SFT +LCAT +SFAT +LCAC +Scale factor on t-moment at node 2. +Load curve ID giving axial tensile yield force vs. total tensile +(elastic + plastic) strain or vs. elongation. See AOPT above. All +values are positive. See *DEFINE_CURVE. +Scale factor on axial tensile force. +Load curve ID giving compressive yield force vs. + total +compressive (elastic + plastic) strain or vs. elongation. See AOPT +above. All values are positive. See *DEFINE_CURVE. +SFAC +Scale factor on axial tensile force. +ALPHA +Parameter to define yield surface. +VARIABLE +DESCRIPTION +BETA +Parameter to define yield surface. +GAMMA +Parameter to define yield surface. +DELTA +Parameter to define yield surface. +A +B +Parameter to define yield surface. +Parameter to define yield surface. +FOFFS +Force offset for yield surface . +SIGY +Yield stress of material. +D +W +TF +TW +PHI_T +PHI_C +PHI_B +Depth of section used to calculate interaction curve. +Width of section used to calculate interaction curve. +Flange thickness of section used to calculate interaction curve. +Web thickness used to calculate interaction curve. +Factor on tensile capacity, φt +Factor on compression capacity, φc +Factor on bending capacity, φb +PR1 - PR4 +Plastic rotation thresholds 1 to 4 +TS1 - TS4 +Tensile axial strain thresholds 1 to 4 +CS1 - CS4 +Compressive axial strain thresholds 1 to 4 +Remarks: +Yield surface for formulation type 1 is of the form: +𝜓 = ( +𝑀𝑠 +𝑀𝑦𝑠 +) ++ ( +𝑀𝑡 +𝑀𝑦𝑡 +) ++ 𝐴 ( +𝐹𝑦 +) ++ 𝐵 ( +) +− 1 +𝐹𝑦 +Where, +𝑀𝑠, 𝑀𝑡 = moments about local s and t axes +𝑀𝑦𝑠, 𝑀𝑦𝑡 = current yield moments +𝐹 = axial force +𝐹𝑦 = Yield force; LCAC in compression or LCAT in tension +𝛼, 𝛽, 𝛾, 𝛿 = Input parameters; must be greater than or equal to 1.1 +𝐴, 𝐵 = input paramaters +If α, β, γ, δ, A and B are all set to zero then the following default values are used: +ALPHA +BETA +GAMMA +DELTA +A +B += + = + = += + = + = + 2.0 + 2.0 + 2.0 + 4.0 + 2.0 +-1.0 +FOFFS offsets the yield surface parallel to the axial force axis. It is the compressive axial +force at which the maximum bending moment capacity about the local s-axis +(determined by LCPMS and SFS), and that about the local t-axis (determined by LCPMT +and SFT), occur. For steel beams and columns, the value of FOFFS is usually zero. For +reinforce concrete beams, columns and shear walls, the maximum bending moment +capacity occurs corresponding to a certain compressive axial force, FOFFS. The value of +FOFFS can be input as either positive or negative. Internally, LS-DYNA converts +FOFFS to, and regards compressive axial force as, negative. +Interaction surface FTYPE 4 calculates a utilisation parameter using the yield force and +moment data given on card 2, but the elements remain elastic even when the forces or +moments exceed yield values. This is done for consistency with the design code OBE +AISC LRFD (2000). The utilisation calculation is as follows: +Ultilisation = +𝐾1𝐹 +𝜙𝐹𝑦 ++ +𝐾2 +𝜙𝑏 +( +𝑀𝑠 +𝑀𝑦𝑠 ++ +𝑀𝑡 +𝑀𝑦𝑡 +) +where, +and, +𝑀𝑠, 𝑀𝑡𝑀𝑦𝑠, 𝑀𝑦𝑡, 𝐹𝑦 are defined as in the preceding equation +𝜙 = from PHI_ T under tension; PHI_ C under compression +𝜙𝑏 = take from PHI_ B +𝐾1 = +0.5 +1.0 +⎧ +{{{ +⎨ +{{{ +⎩ +𝜙𝐹𝑦 +𝜙𝐹𝑦 +< 0.2 +≥ 0.2 +𝐾2 = +1.0 +9⁄ +⎧ +{{{ +⎨ +{{{ +⎩ +𝜙𝐹𝑦 +𝜙𝐹𝑦 +< 0.2 +≥ 0.2 +Interaction surface FTYPE 5 is similar to type 4 (calculates a utilisation parameter using +the yield data, but the elements do not yield). The equations are taken from Australian +code AS4100. The user must select appropriate values of α, β, γ and δ using the various +clauses of Section 8 of AS4100. It is assumed that the local s-axis is the major axis for +bending. +Utilisation = max(𝑈1, 𝑈2, 𝑈3, 𝑈4, 𝑈5) +𝑈1 = +𝑈2 = +𝛽𝜙𝑐𝐹𝑦𝑐 +𝜙𝑡𝐹𝑦𝑡 +𝑈3 = [ +𝑈4 = [ +𝑀𝑠 +𝐾2𝜙𝑏𝑀𝑦𝑠 +𝑀𝑠 +𝐾4𝜙𝑏𝑀𝑦𝑠 +𝜙𝑐𝐹𝑦𝑐 ++ +] +] ++ [ ++ [ +𝑀𝑠 +𝜙𝑏𝑀𝑦𝑠 ++ +𝑀𝑡 +𝐾1𝜙𝑏𝑀𝑦𝑡 +𝑀𝑡 +𝐾3𝜙𝑏𝑀𝑦𝑡 +𝑀𝑡 +𝜙𝑏𝑀𝑦𝑡 +used for members in compression +used for members in tension +used for members in compression +used for members in tension +used for all members +] +] +𝑈5 = +where, +and, +𝑀𝑠, 𝑀𝑡, 𝐹, 𝑀𝑦𝑠, 𝑀𝑦𝑡, 𝐹𝑦𝑡, 𝐹𝑦𝑐 are as defined above +𝐾1 = 1.0 − +𝛽𝜙𝑐𝐹𝑦𝑐 +𝐾2 = min [𝐾1, 𝛼 (1.0 − +𝛿𝜙𝑐𝐹𝑦𝑐 +)] +𝐾3 = 1.0 − +𝜙𝑡𝐹𝑦𝑡 +𝐾4 = min [K3, 𝛼 (1.0 + +𝜙𝑡𝐹𝑦𝑡 +)] +where +𝐾1, 𝐾2, 𝐾3𝐾4 are subject to a minimum value of 10−6, +𝛼, 𝛽, 𝛾, 𝛿, 𝜙𝑡, 𝜙𝑐, 𝜙𝑏 are input parameters +The option for degrading moment behavior changes the meaning of the plastic +moment-rotation curve as follows: +If DEGRAD = 0 (not recommended), the x-axis points on the curve represent current +plastic rotation (i.e. total rotation minus the elastic component of rotation). This +quantity can be positive or negative depending on the direction of rotation; during +hysteresis the behavior will repeatedly follow backwards and forwards along the same +curve. The curve should include negative and positive rotation and moment values. +This option is retained so that results from existing models will be unchanged. +If DEGRAD = 1, the x-axis points represent cumulative absolute plastic rotation. This +quantity is always positive, and increases whenever there is plastic rotation in either +direction. Thus, during hysteresis, the yield moments are taken from points in the input +curve with increasingly positive rotation. If the curve shows a degrading behavior +(reducing moment with rotation), then, once degraded by plastic rotation, the yield +moment can never recover to its initial value. This option can be thought of as having +“fatigue-type” hysteretic damage behavior, where all plastic cycles contribute to the +total damage. +If DEGRAD = 2, the x-axis points represent the high-tide value (always positive) of the +plastic rotation. This quantity increases only when the absolute value of plastic rotation +exceeds the previously recorded maximum. If smaller cycles follow a larger cycle, the +plastic moment during the small cycles will be constant, since the high-tide plastic +rotation is not altered by the small cycles. Degrading moment-rotation behavior is +possible. This option can be thought of as showing rotation-controlled damage, and +follows the FEMA approach for treating fracturing joints. +DEGRAD applies also to the axial behavior. The same options are available as for +rotation: DEGRAD = 0 gives unchanged behavior from previous versions; DEGRAD = 1 +gives a fatigue-type behavior using cumulative plastic strain; and DEGRAD = 2 gives +FEMA-type behavior, where the axial load capacity depends on the high-tide tensile +and compressive strains. The definition of strain for this purpose is according to AOPT +on Card 1 – it is expected that AOPT = 2 will be used with DEGRAD = 2. The “axial +strain” variable plotted by post-processors is the variable defined by AOPT. +The output variables plotted as “plastic rotation” have special meanings for this +material model as follows – note that hinges form only at Node 2: + “Plastic rotation at End 1” is really a high-tide mark of absolute plastic rotation at Node +2, defined as follows: +1. Current plastic rotation is the total rotation minus the elastic component of +rotation. +2. Take the absolute value of the current plastic rotation, and record the maximum +achieved up to the current time. This is the high-tide mark of plastic rotation. +If DEGRAD = 0, “Plastic rotation at End 2” is the current plastic rotation at Node 2. +If DEGRAD = 1 or 2, “Plastic rotation at End 2” is the current total rotation at Node 2. +The total rotation is a more intuitively understood parameter, e.g. for plotting +hysteresis loops. However, with DEGRAD = 0, the previous meaning of that output +variable has been retained such that results from existing models are unchanged. +FEMA thresholds are the plastic rotations at which the element is deemed to have +passed from one category to the next, e.g. “Elastic”, “Immediate Occupancy”, “Life +Safe”, etc. The high-tide plastic rotation (maximum of Y and Z) is checked against the +user-defined limits FEMA1, FEMA2, etc. The output flag is then set to 0, 1, 2, 3, or 4: 0 +means that the rotation is less than FEMA1; 1 means that the rotation is between +FEMA1 and FEMA2, and so on. By contouring this flag, it is possible to see quickly +which joints have passed critical thresholds. +For this material model, special output parameters are written to the d3plot and d3thdt +files. The number of output parameters for beam elements is automatically increased to +20 (in addition to the six standard resultants) when parts of this material type are +present. Some post-processors may interpret this data as if the elements were +integrated beams with 4 integration points. Depending on the post-processor used, the +data may be accessed as follows: +Extra variable 16 (or Integration point 4 Axial Stress): +Extra variable 17 (or Integration point 4 XY Shear Stress): Current utilization +Extra variable 18 (or Integration point 4 ZX Shear Stress): Maximum utilization +FEMA rotation flag +to +Extra variable 20 (or Integration point 4 Axial Strain): +date +FEMA axial flag +“Utilization” is the yield parameter, where 1.0 is on the yield surface. +*MAT_SOIL_BRICK +Purpose: This is Material Type 192. It is intended for modeling over-consolidated clay. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +RO +RLAMDA RKAPPA +RIOTA +RBETA1 +RBETA2 +RMU +Type +A8 +F +F +F +F +F +F +F +Default +1.0 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RNU +RLCID +TOL +PGCL +SUB-INC +BLK +GRAV +THEORY +Type +F +F +F +F +F +F +F +Default +0.0005 +9.807 +I +0 +Additional card for THEORY > 0. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RVHHH +XSICRIT +ALPHA +RVH +RNU21 +ANISO_4 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +RLAMDA +Material coefficient +VARIABLE +DESCRIPTION +RKAPPA +Material coefficient +RIOTA +Material coefficient +RBETA1 +Material coefficient +RBETA2 +Material coefficient +RMU +Shape factor coefficient. This parameter will modify the shape of +the yield surface used. 1.0 implies a von Mises type surface, but +1.1 to 1.25 is more indicative of soils. The default value is 1.0. +RNU +Poisson’s ratio +RLCID +TOL +PGCL +SUB-INC +BLK +GRAV +Load curve identification number referring to a curve defining up +to 10 pairs of ‘string-length’ vs G/Gmax points. +User defined tolerance for convergence checking. Default value is +set to 0.02. +Pre-consolidation ground level. This parameter defines the +maximum surface level (relative to z = 0.0 in the model) of the soil +throughout geological history. + This is used calculate the +maximum over burden pressure on the soil elements. +User defined strain increment size. This is the maximum strain +increment that the material model can normally cope with. If the +value is exceeded a warning is echoed to the d3hsp file. +The elastic bulk stiffness of the soil. This is used for the contact +stiffness only. +The gravitational acceleration. This is used to calculate the +element stresses due the overlying soil. Default is set to 9.807 +m/s2. +THEORY +Version of material subroutines used . +EQ.0: 1995 version, vectorized (Default) +EQ.4: 2003 version, unvectorized +RVHHH +Anisotropy ratio Gvh / Ghh (default = Isotropic behavior) +XSICRIT +Anisotropy parameter +*MAT_SOIL_BRICK +DESCRIPTION +ALPHA +Anisotropy parameter +RVH +Anisotropy ratio Ev / Eh +RNU21 +Anisotropy ratio 𝜈2/𝜈1 +ANISO_4 +Anisotropy parameter +Remarks: +1. This material type requires that the model is oriented such that the z-axis is +defined in the upward direction. Compressive initial stress must be defined, +e.g. using *INITIAL_STRESS_SOLID or *INITIAL_STRESS_DEPTH. +The recommended unit system is kN, meters, seconds, tonnes. There are some +built-in defaults that assume stress units of KN/m2. +Over-consolidated clays have suffered previous loading to higher stress levels +than are present at the start of the analysis. This could have occurred due to ice +sheets during previous ice ages, or the presence of soil or rock that has subse- +quently been eroded. The maximum vertical stress during that time is assumed +to be: +𝜎VMAX = RO × GRAV × (PGCL − 𝑍el) +where +RO, GRAV, and PGCL = input parameters +𝑍el = z coordinate of center of element +Since that time, the material has been unloaded until the vertical stress equals +the user-defined initial vertical stress. The previous load/unload history has a +significant effect on subsequent behavior, e.g. the horizontal stress in an over- +consolidated clay may be greater than the vertical stress. +This material model creates a load/unload cycle for a sample element of each +material of this type, stores in a scratch file the horizontal stress and history +variables as a function of the vertical stress, and interpolates these quantities +from the defined initial vertical stress for each element. Therefore the initial +horizontal stress seen in the output files will be different from the input initial +horizontal stress. +This material model is developed for a Geotechnical FE program (Oasys Ltd.’s +SAFE) written by Arup. The default THEORY = 0 gives a vectorized version +ported from SAFE in the 1990’s. Since then the material model has been devel- +oped further in SAFE; the most recent porting is accessed using THEORY = 4 +(recommended); however, this version is not vectorized and will run more +slowly on most computer platforms. +2. The shape factor for a typical soil would be 1.25. Do not use values higher than +1.35. +*MAT_DRUCKER_PRAGER +Purpose: This is Material Type 193. This material enables soil to be modeled +effectively. The parameters used to define the yield surface are familiar geotechnical +parameters (i.e. angle of friction). The modified Drucker-Prager yield surface is used in +this material model enabling the shape of the surface to be distorted into a more +realistic definition for soils. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +RO +GMOD +RNU +RKF +PHI +CVAL +PSI +Type +A8 +F +F +F +F +F +F +F +Default +1.0 +0.0 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +STR_LIM +Type +F +Default +0.005 + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable GMODDP +PHIDP +CVALDP +PSIDP +GMODGR +PHIGR +CVALGR +PSIGR +Type +F +F +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +VARIABLE +DESCRIPTION +GMOD +Elastic shear modulus +RNU +RKF +PHI +Poisson’s ratio +Failure surface shape parameter +Angle of friction (radians) +CVAL +Cohesion value +PSI +Dilation angle (radians) +STR_LIM +Minimum shear strength of material is given by STR_LIM*CVAL +GMODDP +Depth at which shear modulus (GMOD) is correct +PHIDP +Depth at which angle of friction (PHI) is correct +CVALDP +Depth at which cohesion value (CVAL) is correct +PSIDP +Depth at which dilation angle (PSI) is correct +GMODGR +Gradient at which shear modulus (GMOD) increases with depth +PHIGR +Gradient at which friction angle (PHI) increases with depth +CVALGR +Gradient at which cohesion value (CVAL) increases with depth +PSIGR +Gradient at which dilation angle (PSI) increases with depth +Remarks: +1. This material type requires that the model is oriented such that the z-axis is +defined in the upward direction. The key parameters are defined such that may +vary with depth (i.e. the z-axis). +2. The shape factor for a typical soil would be 0.8, but should not be pushed +further than 0.75. +3. +If STR_LIM is set to less than 0.005, the value is reset to 0.005. +4. The yield function is defined as: +t – p.tanβ – d = 0 +where: +p = hydrostatic stress = J1/3 +t = (q/2){a – b(r/q)3} +q = Von Mises stress = √(3J2) +a = 1 + 1/K +b = 1 – 1/K +K = input parameter RKF +r = (27 J3/2)1/3 +J2,J3 = second and third deviatoric stress invariants +tanβ = 6 sinφ / (3-sinφ) +d = 6 C cosφ / (3-sinφ) +φ= input parameter PHI +C = input parameter CVAL +*MAT_194 +Purpose: This is Material Type 194. It is for shell elements only. It uses empirically- +derived algorithms to model the effect of cyclic shear loading on reinforced concrete +walls. It is primarily intended for modeling squat shear walls, but can also be used for +slabs. Because the combined effect of concrete and reinforcement is included in the +empirical data, crude meshes can be used. The model has been designed such that the +minimum amount of input is needed: generally, only the variables on the first card need +to be defined. +NOTE: This material does not support specification of a ma- +terial angle, 𝛽𝑖, for each through-thickness integra- +tion point of a shell. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +6 +7 +TMAX +F +8 +I +Default +none +none +none +0.0 +0.0 +Include the following data if “Uniform Building Code” formula for maximum shear +strength or tensile cracking are required – otherwise leave blank. + Card 2 +Variable +1 +FC +2 +3 +4 +5 +6 +PREF +FYIELD +SIG0 +UNCONV +ALPHA +Type +F +F +F +F +F +F +7 +FT +F +8 +ERIENF +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Variable +Type +1 +A +F +*MAT_RC_SHEAR_WALL +2 +B +F +3 +C +F +4 +D +F +5 +E +F +6 +F +F +7 +8 +Default +0.05 +0.55 +0.125 +0.66 +0.25 +1.0 + Card 4 +Variable +1 +Y1 +Type +F +2 +Y2 +F +3 +Y3 +F +4 +Y4 +F +5 +Y5 +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 + Card 5 +Variable +1 +T1 +Type +F +2 +T2 +F +3 +T3 +F +4 +T4 +F +5 +T5 +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +6 +7 +8 +6 +7 +8 + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +AOPT +Type +F +Default +0.0 +Variable +1 +XP +Type +F +2 +YP +F +3 +ZP +F +4 +A1 +F +5 +A2 +F +6 +A3 +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +*MAT_194 +7 +8 + Card 8 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +BETA +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +TMAX +FC +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Young’s Modulus +Poisson’s Ratio +Ultimate in-plane shear stress. If set to zero, LS-DYNA will +calculate TMAX based on the formulae in the Uniform Building +Code, using the data on card 2. See Remarks. +Unconfined Compressive Strength of concrete (used in the +calculation of ultimate shear stress; crushing behavior is not +modeled) +PREF +Percent reinforcement, e.g. if 1.2% reinforcement, enter 1.2 +FYIELD +Yield stress of reinforcement +SIG0 +Overburden stress (in-plane compressive stress) - used in the +calculation of ultimate shear stress. Usually sig0 is left as zero. +*MAT_RC_SHEAR_WALL +DESCRIPTION +UCONV +Unit conversion factor. UCONV is expected to be set such that, +UCONV = √1.0 PSI in the model's stress units. +This used to convert the ultimate tensile stress of concrete which +is expressed as √FC where FC is given in PSI. Therefore a unit +conversion factor of √PSI Stress Unit + is required. Examples: +⁄ +UCONV = 83.3 = √6894 if stress unit is N/m2 +UCONV = 0.083 if stress unit is MN/m2 or N/mm2 +ALPHA +Shear span factor - see below. +FT +ERIENF +A +B +C +D +E +F +Cracking stress in direct tension - see notes below. Default is 8% +of the cylinder strength. +Young’s Modulus of reinforcement. Used in calculation of post- +cracked stiffness - see notes below. +Hysteresis constants determining the shape of the hysteresis +loops. +Hysteresis constants determining the shape of the hysteresis +loops. +Hysteresis constants determining the shape of the hysteresis +loops. +Hysteresis constants determining the shape of the hysteresis +loops. +Hysteresis constants determining the shape of the hysteresis +loops. +Strength degradation factor. After the ultimate shear stress has +been achieved, F multiplies the maximum shear stress from the +curve for subsequent reloading. F = 1.0 implies no strength +degradation (default). F = 0.5 implies that the strength is halved +for subsequent reloading. +Y1, Y2, …, Y5 +Engineering shear strain points on stress-strain curve. By default +these are calculated from the values on card 1. See below for +more guidance. +VARIABLE +T1, T2, …, T5 +DESCRIPTION +Shear stress points on stress-strain curve. By default these are +calculated from the values on card 1. See below for more +guidance. +AOPT +Material axes option: +EQ.0.0: locally orthotropic with material axes determined by +element nodes as shown in Figure M2-1, and then ro- +tated about the shell element normal by the angle BE- +TA. Nodes 1, 2, and 4 of an element are identical to the +nodes used for the definition of a coordinate system as +by *DEFINE_COORDINATE_NODES. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: applicable to shell elements only. + This option +determines locally orthotropic material axes by offset- +ting the material axes by an angle to be specified from +a line in the plane of the shell determined by taking the +cross product of the vector v defined below with the +shell normal vector. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +XP, YP, ZP +Coordinates of point 𝐩 for AOPT = 1. +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3. +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2. +BETA +Material angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA. +Remarks: +The element is linear elastic except for in-plane shear and tensile cracking effects. +Crushing due to direct compressive stresses are modeled only insofar as there is an in- +plane shear stress component. It is not recommended that this model be used where +nonlinear response to direct compressive or loads is important. +Note that the in-plane shear stress 𝑡𝑥𝑦 is defined as the shear stress in the element’s local +𝑥-𝑦 plane. This is not necessarily equal to the maximum shear stress in the plane: for +example, if the principal stresses are at 45 degrees to the local axes, 𝑡𝑥𝑦 is zero. +Therefore it is important to ensure that the local axes are appropriate - for a shear wall +the local axes should be vertical or horizontal. By default, local 𝑥 points from node 1 to +node 2 of the element. It is possible to change the local axes by using AOPT > 0. +If TMAX is set to zero, the ultimate shear stress is calculated using a formula in the +Uniform Building Code 1997, section 1921.6.5: +TMAXUBC = UCONV × ALPHA × √FC + RO × FY +where, +UCONV = unit conversion factor, see varriable list +ALPHA = aspect ratio += 2.0 for ℎ 𝑙⁄ ∈ (2.0, ∞) increases linearly to 3.0 for ℎ 𝑙⁄ ∈ (2.0,1.5) +FC = unconfined compressive strength of concrete +RO = fraction of reinforcement += (percent reinforcement) 100 +⁄ +FY = yield stress of reinforcement +To this we add shear stress due to the overburden to obtain the ultimate shear stress: +TMAXUBC = TMAXUBC + SIG0 +where +SIG0 = in plane compressive stress under static equilibrium conditions +The UBC formula for ultimate shear stress is generally conservative (predicts that the +wall is weaker than shown in test), sometimes by 50% or more. A less conservative +formula is that of Fukuzawa: +TMAX = max [(0.4 + +𝐴𝑐 +𝐴𝑤 +) , 1] × 2.7 × (1.9 + +𝐿𝑣 +) × UCONV+√FC + 0.5 +× RO × FY + SIG0 +where +𝐴𝐶 = Cross-sectional area of stiffening features such as columns or flanges +𝐴𝑤 = Cross-sectional area of wall +⁄ +𝑀 𝐿𝑣⁄ = Aspect ratio of wall height length +Other terms are as above. This formula is not included in the material model: TMAX +should be calculated by hand and entered on Card 1 if the Fukuzawa formula is +required. +It should be noted that none of the available formulae, including Fukuzawa, predict the +ultimate shear stress accurately for all situations. Variance from the experimental +results can be as great as 50%. +The shear stress vs shear strain curve is then constructed automatically as follows, using +the algorithm of Fukuzawa extended by Arup: +1. Assume ultimate engineering shear strain, 𝛾𝑢 = 0.0048 +2. First point on curve, corresponding to concrete cracking, is at +(0.3 × +TMAX +, 0.3 × TMAX), +where 𝐺 is the elastic shear modulus given by +𝐺 = +2(1 + 𝜈) +. +3. Second point, corresponding to the reinforcement yield, is at +4. Third point, corresponding to the ultimate strength, is at +(0.5 × 𝛾𝑢, 0.8 × TMAX). +(𝛾𝑢, TMAX). +5. Fourth point, corresponding to the onset of strength reduction, is at +6. Fifth point, corresponding to failure is at +(2𝛾𝑢,TMAX). +(3𝛾𝑢, 0.6 × TMAX). +After failure, the shear stress drops to zero. The curve points can be entered by the user +if desired, in which case they over-ride the automatically calculated curve. However, it +is anticipated that in most cases the default curve will be preferred due to ease of input. +Hysteresis follows the algorithm of Shiga as for the squat shear wall spring . The hysteresis constants which are defined in fields +A, B, C, D, and E can be entered by the user if desired, but it is generally recommended +that the default values be used. +Cracking in tension is checked for the local x and y directions only – this is calculated +separately from the in-plane shear. A trilinear response is assumed, with turning points +at concrete cracking and reinforcement yielding. The three regimes are: +1. Pre-cracking, linear elastic response is assumed using the overall Young’s +Modulus on Card 1. +2. Cracking occurs in the local x or y directions when the tensile stress in that +direction exceeds the concrete tensile strength FT (if not input on Card 2, this +defaults to 8% of the compressive strength FC). Post-cracking, a linear stress- +strain response is assumed up to reinforcement yield at a strain defined by +reinforcement yield stress divided by reinforcement Young’s Modulus. +3. Post-yield, a constant stress is assumed (no work hardening). +Unloading returns to the origin of the stress-strain curve. +For compressive strains the response is always linear elastic using the overall +Young’s Modulus on Card 1. +If insufficient data is entered, no cracking occurs in the model. As a minimum, +FC and FY are needed. +Extra variables are available for post-processing as follows: +Extra variable 1: Current engineering shear strain +Extra variable 2: Shear status: 0, 1, 2, 3, 4, or 5– see below +Extra variable 3: Maximum direct strain so far in local 𝑥 direction (for ten- +sile cracking) +Extra variable 4: Maximum direct strain so far in local 𝑦 direction (for ten- +sile cracking) +Extra variable 5: Tensile status: 0, 1 or 2 = elastic, cracked, or yielded re- +spectively. +The shear status shows how far along the shear stress-strain curve each element +has progressed, e.g. status 2 means that the element has passed the second +point on the curve. These status levels correspond to performance criteria in +building design codes such as FEMA. +*MAT_195 +This is Material Type 195 for beam elements. An elasto-plastic material with an +arbitrary stress versus strain curve and arbitrary strain rate dependency can be defined. +See also Remark below. Also, failure based on a plastic strain or a minimum time step +size can be defined. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +6 +7 +8 +SIGY +ETAN +FAIL +TDEL +F +F +F +F +Default +none +none +none +none +none +0.0 +10.E+20 10.E+20 + Card 2 +Variable +Type +Default +1 +C +F +0 + Card 3 +1 +2 +P +F +0 +2 +3 +4 +5 +6 +7 +8 +LCSS +LCSR +F +0 +3 +F +0 +4 +5 +6 +7 +8 +Variable +NOTEN +TENCUT +SDR +Type +Default +I +0 +F +F +E15.0 +0.0 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +E +PR +SIGY +ETAN +FAIL +*MAT_CONCRETE_BEAM +DESCRIPTION +Young’s modulus. +Poisson’s ratio. +Yield stress. +Tangent modulus, ignored if (LCSS.GT.0) is defined. +Failure flag. +LT.0.0: user defined failure subroutine is called to determine +failure +EQ.0.0: failure is not considered. This option is recommended +if failure is not of interest since many calculations will +be saved. +GT.0.0: plastic strain to failure. When the plastic strain reaches +this value, the element is deleted from the calculation. +TDEL +Minimum time step size for automatic element deletion. +C +P +LCSS +Strain rate parameter, C, see formula below. +Strain rate parameter, P, see formula below. +Load curve ID or Table ID. Load curve ID defining effective +stress versus effective plastic strain. If defined EPS1-EPS8 and +ES1-ES8 are ignored. The table ID defines for each strain rate +value a load curve ID giving the stress versus effective plastic +strain for that rate, See Figure M16-1 stress versus effective plastic +strain curve for the lowest value of strain rate is used if the strain +rate falls below the minimum value. Likewise, the stress versus +effective plastic strain curve for the highest value of strain rate is +used if the strain rate exceeds the maximum value. The strain +rate parameters: C and P; +LCSR +Load curve ID defining strain rate scaling effect on yield stress. +NOTEN +No-tension flag, +EQ.0: beam takes tension, +EQ.1: beam takes no tension, +EQ.2: beam takes tension up to value given by TENCUT. +TENCUT +Tension cutoff value. +VARIABLE +DESCRIPTION +SDR +Stiffness degradation factor. +Remarks: +The stress strain behavior may be treated by a bilinear stress strain curve by defining +the tangent modulus, ETAN. An effective stress versus effective plastic strain curve +(LCSS) may be input instead of defining ETAN. The cost is roughly the same for either +approach. The most general approach is to use the table definition (LCSS) discussed +below. +Three options to account for strain rate effects are possible. +1. Strain rate may be accounted for using the Cowper and Symonds model which +scales the yield stress with the factor +1 + ( +𝑝⁄ +) +𝜀̇ +where 𝜀̇ is the strain rate. 𝜀̇ = √𝜀̇𝑖𝑗𝜀̇𝑖𝑗. +2. For complete generality a load curve (LCSR) to scale the yield stress may be +input instead. In this curve the scale factor versus strain rate is defined. +3. +If different stress versus strain curves can be provided for various strain rates, +the option using the reference to a table (LCSS) can be used. +*MAT_GENERAL_SPRING_DISCRETE_BEAM +This is Material Type 196. This model permits elastic and elastoplastic springs with +damping to be represented with a discrete beam element of type 6 by using six springs +each acting about one of the six local degrees-of-freedom. For elastic behavior, a load +curve defines force or moment versus displacement or rotation. For inelastic behavior, +a load curve defines yield force or moment versus plastic deflection or rotation, which +can vary in tension and compression. +The two nodes defining a beam may be coincident to give a zero length beam, or offset +to give a finite length beam. For finite length discrete beams the absolute value of the +variable SCOOR in the SECTION_BEAM input should be set to a value of 2.0, which +causes the local r-axis to be aligned along the two nodes of the beam to give physically +correct behavior. The distance between the nodes of a beam should not affect the +behavior of this material model. A triad is used to orient the beam for the directional +springs. +3 +4 +5 +6 +7 +8 + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +Degree of Freedom Card Pairs. For each active degree of freedom include a pair of +cards 2 and 3. This data is terminated by the next keyword (“*”) card or when all six +degrees of freedom have been specified. + Card 2 +1 +2 +Variable +DOF +TYPE +Type +I + Card 3 +1 +I +2 +Variable +FLCID +HLCID +Type +F +F +3 +K +F +3 +C1 +F +4 +D +F +4 +C2 +F +5 +6 +7 +8 +CDF +TDF +F +5 +F +6 +DLE +GLCID +F +I +7 +VARIABLE +DESCRIPTION +MID +RO +DOF +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density, see also volume in *SECTION_BEAM definition. +Active degree-of-freedom, a number between 1 and 6 inclusive. +Each value of DOF can only be used once. The active degree-of- +freedom is measured in the local coordinate system for the +discrete beam element. +TYPE +The default behavior is elastic. For inelastic behavior input 1. +K +D +CDF +TDF +FLCID +Elastic loading/unloading stiffness. This is required input for +inelastic behavior. +Optional viscous damping coefficient. +Compressive displacement at failure. Input as a positive number. +After failure, no forces are carried. This option does not apply to +zero length springs. +EQ.0.0: inactive. +Tensile displacement at failure. After failure, no forces are +carried. +EQ.0.0: inactive. +Load curve ID, see *DEFINE_CURVE. For option TYPE = 0, this +curve defines force or moment versus deflection for nonlinear +elastic behavior. For option TYPE = 1, this curve defines the yield +force versus plastic deflection. If the abscissa of the first point of +the curve is 0. the force magnitude is identical in tension and +compression, i.e., only the sign changes. If not, the yield stress in +the compression is used when the spring force is negative. The +plastic displacement increases monotonically in this implementa- +tion. The load curve is required input. +HLCID +Load curve ID, see *DEFINE_CURVE, defining force versus +relative velocity (Optional). If the origin of the curve is at (0,0) the +force magnitude is identical for a given magnitude of the relative +velocity, i.e., only the sign changes. +C1 +C2 +Damping coefficient. +Damping coefficient +*MAT_GENERAL_SPRING_DISCRETE_BEAM +DESCRIPTION +DLE +Factor to scale time units. +GLCID +Optional load curve ID, see *DEFINE_CURVE, defining a scale +factor versus deflection for load curve ID, HLCID. If zero, a scale +factor of unity is assumed. +Remarks: +If TYPE = 0, elastic behavior is obtained. In this case, if the linear spring stiffness is +used, the force, F, is given by: +𝐹 = K × Δ𝐿 + D × Δ𝐿̇ +but if the load curve ID is specified, the force is then given by: +𝐹 = 𝐾 𝑓 (Δ𝐿) [1 + C1 × Δ𝐿̇ + C2 × sgn(Δ𝐿̇)ln (max {1. , +∣Δ𝐿̇∣ +DLE +})] + D×Δ𝐿̇ + 𝑔(Δ𝐿)ℎ(Δ𝐿̇) +In these equations, Δ𝐿 is the change in length +Δ𝐿 = current length − initial length +For the first three degrees of freedom the parameters on cards 2 and 3 have dimensions +as shown below. Being angular in nature, the next three degrees of freedom involve +moment instead of force and angle instead of length, but are otherwise identical. +[K] = +[D] = +⎧ [force] +{ +[length] +⎨ +{ +⎩ +unitless +[force] +[velocity] +FLCID = 0 +FLCID > 0 +[force][time] +[length] += +[FLCID] = [GLCID] = ([length], [force]) +[HLCID] = ([velocity], [force]) +[C1] = +[time] +[length] +[C2] = unitless +[DLE] = +[length] +[time] +If TYPE = 1, inelastic behavior is obtained. In this case, the yield force is taken from the +load curve: +𝐹𝑌 = 𝐹𝑦(Δ𝐿plastic) +where 𝐿plastic is the plastic deflection. A trial force is computed as: +and is checked against the yield force to determine 𝐹: +𝐹𝑇 = 𝐹𝑛 + K × Δ𝐿̇(Δ𝑡) +𝐹 = {𝐹𝑌 +𝐹𝑇 +if 𝐹𝑇 > 𝐹𝑌 +if 𝐹𝑇 ≤ 𝐹𝑌 +The final force, which includes rate effects and damping, is given by: +𝐹𝑛+1 = 𝐹 × [1 + C1 × Δ𝐿̇ + C2 × sgn(Δ𝐿̇)ln (max {1. , +∣Δ𝐿̇∣ +DLE +})] + D × Δ𝐿̇ + 𝑔(Δ𝐿)ℎ(Δ𝐿̇) +Unless the origin of the curve starts at (0,0), the negative part of the curve is used when +the spring force is negative where the negative of the plastic displacement is used to +interpolate, 𝐹𝑦. The positive part of the curve is used whenever the force is positive. +The cross sectional area is defined on the section card for the discrete beam elements, +See *SECTION_BEAM. The square root of this area is used as the contact thickness +offset if these elements are included in the contact treatment. +*MAT_SEISMIC_ISOLATOR +This is Material Type 197 for discrete beam elements. Sliding (pendulum) and +elastomeric seismic isolation bearings can be modeled, applying bi-directional coupled +plasticity theory. The hysteretic behavior was proposed by Wen [1976] and Park, Wen, +and Ang [1986]. The sliding bearing behavior is recommended by Zayas, Low and +Mahin [1990]. The algorithm used for implementation was presented by Nagarajaiah, +Reinhorn, and Constantinou [1991]. Further options for tension-carrying friction +bearings are as recommended by Roussis and Constantinou [2006]. + Element +formulation type 6 must be used. Local axes are defined on *SECTION_BEAM; the +default is the global axis system. It is expected that the local z-axis will be vertical. On +*SECTION_BEAM SCOOR must be set to zero when using this material model. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +A +F +4 +5 +6 +7 +8 +BETA +GAMMA +DISPY +STIFFV +ITYPE +F +F +F +F +I +Default +none +none +1.0 +0.5 +0.5 +0.0 +0.0 +0.0 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable PRELOAD +DAMP +MX1 +MX2 +MY1 +MY2 +Type +Default +F +0 +F +1.0 +F +0 +F +0 +F +0 +F +Sliding Isolator Card. This card is used for ITYPE = 0 or 2. Leave this card blank for +elastomeric isolator (TYPE = 1). + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FMAX +DELF +AFRIC +RADX +RADY +RADB +STIFFL +STIFFTS +Type +Default +F +0 +F +0 +F +0 +F +F +F +F +1.0e20 1.0e20 1.0e20 STIFFV +F +0 +Card 4 for ITYPE = 1 or 2. leave blank for sliding isolator ITYPE = 0: + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FORCEY +ALPHA +STIFFT +DFAIL +FMAXYC +FMAXXT +FMAXYT +YLOCK +Type +Default +F +0 +F +0 +F +F +F +F +F +F +0.5 × +STIFFV +1.0e20 +FMAX +FMAX +FMAX +0.0 + VARIABLE +DESCRIPTION +MID +RO +A +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Nondimensional variable - see below +GAMMA +Nondimensional variable - see below +BETA +DISPY +Nondimensional variable - see below +Yield displacement (length units - must be > 0.0) +STIFFV +Vertical stiffness (force/length units) +ITYPE +Type: +*MAT_SEISMIC_ISOLATOR +DESCRIPTION +EQ.0: sliding (spherical or cylindrical) +EQ.1: elastomeric +EQ.2: sliding (two perpendicular curved beams) +PRELOAD +Vertical preload not explicitly modeled (force units) +DAMP +Damping ratio (nondimensional) +MX1, MX2 +Moment factor at ends 1 and 2 in local X-direction +MY1, MY2 +Moment factor at ends 1 and 2 in local Y-direction +FMAX +Maximum friction coefficient (dynamic) +DELF +Difference between maximum +coefficient +friction and static +friction +AFRIC +Velocity multiplier in sliding friction equation (time/length units) +RADX +RADY +RADB +Radius for sliding in local X direction +Radius for sliding in local Y direction +Radius of retaining ring +STIFFL +Stiffness for lateral contact against the retaining ring +STIFFTS +Stiffness for tensile vertical response (sliding isolator - default = 0) +FORCEY +ALPHA +STIFFT +DFAIL +Yield force. Used for elastomeric type (ITYPE = 1). Leave blank +for sliding type (0, and 2). +Ratio of postyielding stiffness to preyielding stiffness. Used for +elastomeric type (ITYPE = 1). Leave blank for sliding type (0, and +2). +Stiffness for tensile vertical response (elastomeric isolator). Used +for elastomeric type (ITYPE = 1). Leave blank for sliding type (0, +and 2). +Lateral displacement at which the isolator fails. Used for +elastomeric type (ITYPE = 1). Leave blank for sliding type (0, and +2). +DESCRIPTION +Max friction coefficient (dynamic) for local Y-axis (compression). +Used for ITYPE = 2. Leave blank for ITYPE = 0 or 1. +Max friction coefficient (dynamic) for local X-axis (tension). Used +for ITYPE = 2. Leave blank for ITYPE = 0 or 1. +Max friction coefficient (dynamic) for local Y-axis (tension). Used +for ITYPE = 2. Leave blank for ITYPE = 0 or 1. +Stiffness locking the local Y-displacement (optional -single-axis +sliding). Used for ITYPE = 2. Leave blank for ITYPE = 0 or 1. + VARIABLE +FMAXYC +FMAXXT +FMAXYT +YLOCK +Remarks: +The horizontal behavior of both types is governed by plastic history variables Zx, Zy +that evolve according to equations given in the reference; A, gamma and beta and the +yield displacement are the input parameters for this. The intention is to provide smooth +build-up, rotation and reversal of forces in response to bidirectional displacement +histories in the horizontal plane. The theoretical model has been correlated to +experiments on seismic isolators. +The RADX, RADY inputs for the sliding isolator are optional. If left blank, the sliding +surface is assumed to be flat. A cylindrical surface is obtained by defining either RADX +or RADY; a spherical surface can be defined by setting RADX = RADY. The effect of +the curved surface is to add a restoring force proportional to the horizontal +displacement from the center. As seen in elevation, the top of the isolator will follow a +curved trajectory, lifting as it displaces away from the center. +The vertical behavior for all types is linear elastic, but with different stiffnesses for +tension and compression. By default, the tensile stiffness is zero for the sliding types. +The vertical behavior for the elastomeric type is linear elastic; in the case of uplift, the +tensile stiffness will be different to the compressive stiffness. For the sliding type, +compression is treated as linear elastic but no tension can be carried. +Vertical preload can be modeled either explicitly (for example, by defining gravity), or +by using the PRELOAD input. PRELOAD does not lead to any application of vertical +force to the model. It is added to the compression in the element before calculating the +friction force and tensile/compressive vertical behavior. +ITYPE = 0 is used to model a single (spherical) pendulum bearing. Triple pendulum +bearings can be modelled using three of these elements in series, following the method +described by Fenz and Constantinou 2008. The input properties for the three elements +(given by⎯Reff1,⎯μ1,⎯d1, ⎯a1, etc) are calculated from the properties of the actual triple +bearing (given by Reff1, μ1, d1, a1, etc) as follows: +ITYPE = 2 is intended to model uplift-prevention sliding isolators that consist of two +perpendicular curved beams joined by a connector that can slide in slots on both beams. +The beams are aligned in the local X and Y axes respectively. The vertical displacement +is the sum of the displacements induced by the respective curvatures and slider +displacements along the two beams. Single-axis sliding is obtained by using YLOCK to +lock the local-Y displacement. To resist uplift, STIFFTS must be defined (recommended +value: same as STIFFV). This isolator type allows different friction coefficients on each +beam, and different values in tension and compression. The total friction, taking into +account sliding velocity and the friction history functions, is first calculated using +FMAX and then scaled by FMAXXT/FMAX etc as appropriate. For this reason, FMAX +should not be zero. +DAMP is the fraction of critical damping for free vertical vibration of the isolator, based +on the mass of the isolator (including any attached lumped masses) and its vertical +stiffness. The viscosity is reduced automatically if it would otherwise infringe +numerical stability. Damping is generally recommended: oscillations in the vertical +force would have a direct effect on friction forces in sliding isolators; for isolators with +curved surfaces, vertical oscillations can be excited as the isolator slides up and down +the curved surface. It may occasionally be necessary to increase DAMP if these +oscillations become significant. +This element has no rotational stiffness - a pin joint is assumed. However, if required, +moments can be generated according to the vertical load multiplied by the lateral +displacement of the isolator. The moment about the local X-axis (i.e. the moment that is +dependent on lateral displacement in the local Y-direction) is reacted on nodes 1 and 2 +of the element in the proportions MX1 and MX2 respectively. Similarly, moments about +the local Y-axis are reacted in the proportions MY1, MY2. These inputs effectively +determine the location of the pin joint. +For example, a pin at the base of the column could be modeled by setting +MX1 = MY1 = 1.0, MX2 = MY2 = 0.0 and ensuring that node 1 is on the foundation, +node 2 at the base of the column - then all the moment is transferred to the foundation. +For the same model, MX1 = MY1 = 0.0, MX2 = MY2 = 1.0 would imply a pin at the top +of the foundation - all the moment is transferred to the column. Some isolator designs +have the pin at the bottom for moments about one horizontal axis, and at the top for the +other axis - these can be modeled by setting MX1 = MY2 = 1.0, MX2 = MY1 = 0.0. It is +expected that all MX1,2, etc lie between 0 and 1, and that MX1+MX2 = 1.0 (or both can +be zero) - e.g. MX1 = MX2 = 0.5 is permitted - but no error checks are performed to +ensure this; similarly for MY1 + MY2. +Density should be set to a reasonable value, say 2000 to 8000 kg/m3. The element mass +will be calculated as density x volume (volume is entered on *SECTION_BEAM). +Note on values for *SECTION_BEAM: +1. Set ELFORM to 6 (discrete beam) +2. VOL (the element volume) might typically be set to 0.1m3 +3. +INER needs to be non-zero (say 1.0) but the value has no effect on the solution +since the element has no rotational stiffness. +4. CID can be left blank if the isolator is aligned in the global coordinate system, +otherwise a coordinate system should be referenced. +5. By default, the isolator will be assumed to rotate with the average rotation of its +two nodes. If the base of the column rotates slightly the isolator will no longer +be perfectly horizontal: this can cause unexpected vertical displacements cou- +pled with the horizontal motion. To avoid this, rotation of the local axes of the +isolator can be eliminated by setting RRCON, SRCON and TRCON to 1.0. This +does not introduce any rotational restraint to the model, it only prevents the +orientation of the isolator from changing as the model deforms. +6. SCOOR must be set to zero. +7. All other parameters on *SECTION_BEAM can be left blank. +Post-processing note: as with other discrete beam material models, the force described +in post-processors as “Axial” is really the force in the local X-direction; “Y-Shear” is +really the force in the local Y-direction; and “Z-Shear” is really the force in the local Z- +direction. +*MAT_JOINTED_ROCK +This is Material Type 198. Joints (planes of weakness) are assumed to exist throughout +the material at a spacing small enough to be considered ubiquitous. The planes are +assumed to lie at constant orientations defined on this material card. Up to three planes +can be defined for each material. See *MAT_MOHR_COULOMB (*MAT_173) for a +preferred alternative to this material model. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +RO +GMOD +RNU +RKF +PHI +CVAL +PSI +Type +A8 +F +F +F +F +F +F +F +Default +1.0 +0.0 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +STR_LIM NPLANES ELASTIC +LCCPDR +LCCPT +LCCJDR +LCCJT +LCSFAC +Type +F +Default +0.005 + Card 3 +1 +I +0 +2 +I +0 +3 +I +0 +4 +I +0 +5 +I +0 +6 +I +0 +7 +I +0 +8 +Variable GMODDP +PHIDP +CVALDP +PSIDP +GMODGR +PHIGR +CVALGR +PSIGR +Type +F +F +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Repeat Card 4 for each plane (maximum 3 planes): + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DIP +STRIKE +CPLANE FRPLANE +TPLANE SHRMAX +LOCAL +Type +F +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +1.e20 +0.0 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +GMOD +Elastic shear modulus +RNU +RKF +PHI +Poisson’s ratio +Failure surface shape parameter +Angle of friction (radians) +CVAL +Cohesion value +PSI +Dilation angle (radians) +STR_LIM +Minimum shear strength of material is given by STR_LIM*CVAL +NPLANES +Number of joint planes (maximum 3) +ELASTIC +Flag = 1 for elastic behavior only +LCCPDR +Load curve for extra cohesion for parent material (dynamic +relaxation) +LCCPT +Load curve for extra cohesion for parent material (transient) +LCCJDR +Load curve for extra cohesion for joints (dynamic relaxation) +LCCJT +Load curve for extra cohesion for joints (transient) +LCSFAC +Load curve giving factor on strength vs time +*MAT_JOINTED_ROCK +DESCRIPTION +GMODDP +Depth at which shear modulus (GMOD) is correct +PHIDP +Depth at which angle of friction (PHI) is correct +CVALDP +Depth at which cohesion value (CVAL) is correct +PSIDP +Depth at which dilation angle (PSI) is correct +GMODGR +Gradient at which shear modulus (GMOD) increases with depth +PHIGR +Gradient at which friction angle (PHI) increases with depth +CVALGR +Gradient at which cohesion value (CVAL) increases with depth +PSIGR +Gradient at which dilation angle (PSI) increases with depth +DIP +Angle of the plane in degrees below the horizontal +DIPANG +Plan view angle (degrees) of downhill vector drawn on the plane +CPLANE +Cohesion for shear behavior on plane +PHPLANE +Friction angle for shear behavior on plane (degrees) +TPLANE +Tensile strength across plane (generally zero or very small) +SHRMAX +Max shear stress on plane (upper +compression) +limit, +independent of +LOCAL +EQ.0: DIP and DIPANG are with respect to the global axes +Remarks: +1. The joint plane orientations are defined by the angle of a “downhill vector” +drawn on the plane, i.e. the vector is oriented within the plane to obtain the +maximum possible downhill angle. DIP is the angle of this line below the hori- +zontal. DIPANG is the plan-view angle of the line (pointing down hill) meas- +ured clockwise from the global Y-axis about the global Z-axis. +2. The joint planes rotate with the rigid body motion of the elements, irrespective +of whether their initial definitions are in the global or local axis system. +3. The full facilities of the modified Drucker Prager model for the matrix material +can be used – see description of Material type 193. Alternatively, to speed up +the calculation, the ELASTIC flag can be set to 1, in which case the yield surface +will not be considered and only RO, GMOD, RNU, GMODDP, GMODGR and +the joint planes will be used. +4. This material type requires that the model is oriented such that the z-axis is +defined in the upward direction. The key parameters are defined such that may +vary with depth (i.e. the z-axis) +5. The shape factor for a typical soil would be 0.8, but should not be pushed +further than 0.75. +6. +If STR_LIM is set to less than 0.005, the value is reset to 0.005. +7. A correction has been introduced into the Drucker Prager model, such that the +yield surface never infringes the Mohr-Coulomb criterion. This means that the +model does not give the same results as a “pure” Drucker Prager model. +8. The load curves LCCPDR, LCCPT, LCCJDR, LCCJT allow additional cohesion +to be specified as a function of time. The cohesion is additional to that specified +in the material parameters. This is intended for use during the initial stages of +an analysis to allow application of gravity or other loads without cracking or +yielding, and for the cracking or yielding then to be introduced in a controlled +manner. This is done by specifying extra cohesion that exceeds the expected +stresses initially, then declining to zero. If no curves are specified, no extra +cohesion is applied. +9. The load curve for factor on strength applies simultaneously to the cohesion +and tan (friction angle) of parent material and all joints. This feature is intend- +ed for reducing the strength of the material gradually, to explore factors of +safety. If no curve is present, a constant factor of 1 is assumed. Values much +greater than 1.0 may cause problems with stability. +10. Extra variables for plotting. By setting NEIPH on *DATABASE_EXTENT_BI- +NARY to 15, the following variables can be plotted in D3PLOT and T/HIS: +Extra Variable 1: mobilized strength fraction for base material +Extra Variable 2: +Extra Variable 3: +Extra Variable 4: +Extra Variable 5: +Extra Variable 6: +Extra Variable 7: +Extra Variable 8: +Extra Variable 9: +Extra Variable 10: current shear utilization for plane 1 +Extra Variable 11: current shear utilization for plane 2 +Extra Variable 12: current shear utilization for plane 3 +rk0 for base material +rlamda for base material + crack opening strain for plane 1 +crack opening strain for plane 2 +crack opening strain for plane 3 +crack accumulated engineering shear strain for plane 1 +crack accumulated engineering shear strain for plane 2 +crack accumulated engineering shear strain for plane 3 +Extra Variable 13: maximum shear utilization to date for plane 1 +Extra Variable 14: maximum shear utilization to date for plane 2 +Extra Variable 15: maximum shear utilization to date for plane 3 +11. Joint planes would generally be defined in the global axis system if they are +taken from survey data. However, the material model can also be used to rep- +resent masonry, in which case the weak planes represent the cement and lie +parallel to the local element axes. +*MAT_HYSTERETIC_REINFORCEMENT +This is Material Type 203 in LS-DYNA. It is intended as an alternative reinforcement +model for layered reinforced concrete shell elements, for use in seismic analysis where +the nonlinear hysteretic behaviour of the reinforcement is important. *PART_COM- +POSITE or *INTEGRATION_BEAM should be used to define some integration points as +a part made of *MAT_HYSTERETIC_REINFORCEMENT, while other integration +points have concrete properties using *MAT_CONCRETE_EC2. When using beam +elements, ELFORM = 1 is required. + Card 1 +1 +Variable +MID +Type +I +2 +RO +F +3 +YM +F +4 +PR +F +5 +6 +7 +8 +SIGY +LAMDA +SBUCK +POWER +F +F +F +F +Default +none +0.0 +0.0 +0.0 +0.0 +0.0 +SIGY +0.5 + Card 2 +1 +2 +3 +4 +5 +6 +7 +Variable +FRACX +FRACY +LCTEN +LCCOMP +AOPT +EBU +DOWNSL +Type +F +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.1 + Card 3 +1 +2 +3 +4 +5 +6 +7 +Variable +DBAR +FCDOW +LCHARD +UNITC +UNITL +Type +F +F +F +F +F +Default +0.0 +0.0 +0.0 +1.0 +1.0 +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EPDAM1 EPDAM2 DRESID +Type +F +F +F +Default +0.0 +0.0 +0.0 +Additional Card for AOPT ≠ 0. + Card 5 +Variable +1 +XP +Type +F +2 +YP +F +3 +ZP +F +4 +A1 +F +5 +A2 +F +6 +A3 +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +7 +8 +Additional Card for AOPT ≠ 0. + Card 6 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +BETA +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +MID +Material identification. A unique number has to be chosen. +RO +YM +PR +Mass density. +Young’s Modulus +Poisson’s Ratio +SIGY +Yield stress +VARIABLE +DESCRIPTION +LAMDA +Slenderness ratio +SBUCK +Initial buckling stress (should be positive) +POWER +Power law for Bauschinger effect (non-dimensional) +FRACX +FRACY +LCTEN +Fraction of reinforcement at this integration point in local 𝑥 +direction +Fraction of reinforcement at this integration point in local 𝑦 +direction +Optional curve providing the factor on SIGY versus plastic strain +(tension) +LCCOMP +Optional curve providing the factor on SBUCK versus plastic +strain (compression) +AOPT +Option for local axis alignment – see material type 2 +EBU +Optional buckling strain (if defined, overrides LAMBDA) +DOWNSL +Initial down-slope of buckling curve as a fraction of YM +(dimensionless) +DBAR +Reinforcement bar diameter used for dowel action. See remarks. +FCDOW +Concrete compressive strength used for dowel action. See notes. +This field has units of stress +LCHARD +Characteristic length for dowel action (length units) +UNITC +UNITL +Factor to convert model stress units to MPa, e.g. is model units +are Newtons and meters, UNITC = 10−6, [UNITC] = 1/[STRESS]. +Factor to convert model length units to millimeters, e.g. if model +units are meters, UNITL = 1000, [UNITL] = 1/[LENGTH]. +EPDAM1 +Accumulated plastic strain at which hysteretic damage begins +EPDAM2 +Accumulated plastic strain at which hysteretic damage is +complete +DRESID +Residual factor remaining after hysteretic damage +XP, YP, ZP +Coordinates of point 𝐩 for AOPT = 1 and 4 +*MAY_HYSTERETIC_REINFORCEMENT +DESCRIPTION +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2 +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3 and 4 +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2 +Remarks: +Reinforcement is treated as bars, acting independently in the local material 𝑥 and 𝑦 +directions. By default, the local material 𝑥-axis is the element 𝑥-axis (parallel to the line +from Node 1 to Node 2), but this may be overridden using AOPT or Element Beta +angles. +The reinforced concrete section should be defined using *INTEGRATION_SHELL, with +some integration points being reinforcement (using this material model) and others +being concrete (using for example *MAT_CONCRETE_EC2). By default, strains in +directions other than the local 𝑥 and 𝑦 are unresisted, so this material model should not +be used alone (without concrete). The area fractions of reinforcement in the local 𝑥 and +𝑦 directions at each integration point are given by the area-weighting for the integration +point on *INTEGRATION_SHELL times the fractions FRACX and FRACY. +The tensile response is elastic perfectly plastic, using yield stress SIGY. Optionally, load +curves may be used to describe the stress-strain response in tension (LCTEN) and +compression (LCCOMP). Either, neither or both curves may be defined. If present, +LCTEN overrides the perfectly-plastic tensile response, and LCCOMP overrides the +buckling curve. The tensile and compressive plastic strains are considered independent +of each other. +Bar buckling may be defined either using the slenderness ratio LAMDA, or by setting +the initial buckling strain EBU and down-slope DOWNSL. If neither are defined, the +bars simply yield in compression. If both are defined, the buckling behaviour defined +by EBU and DOWNSL overrides LAMDA. +The slenderness ratio LAMDA determines buckling behaviour and is defined as, +Where, 𝑘 depends on end conditions, and +𝐿 = unsupported length of reinforcement bars +𝑘𝐿 +, +𝑟 = radius of gyration which for round bars is equal to (bar radius)/√2. +It is expected that users will determine LAMDA accounting for the expected crack +spacing. +The alternative buckling behaviour defined by EBU and DOWNSL is shown below. +Compressive +stress +Yield +-DOWNSL * YM +-0.005 * YM +EBU +EBU + 0.01 +Compressive +strain +Reloading after change of load direction follows a Bauschinger-type curve, leading to +the hysteresis response shown below: +*MAT_HYSTERETIC_REINFORCEMENT +) +( + 800 + 600 + 400 + 200 + 0 +-200 +-400 +-600 +-800 +-30 +-20 +-10 + 0 +Strain % + 10 + 20 + 30 +*MAY_HYSTERETIC_REINFORCEMENT +Two types of damage accumulation may be modelled. Damage based on ductility +(strain) can be modelled using the curves LCTEN and LCCOMP – at high strain, these +curves would show reducing stress with increasing strain. +Damage based on hysteretic energy accumulation can be modelled using the +parameters EPDAM1, EPDAM2 and DRESID. The damage is a function of accumulated +plastic strain: for this purpose, plastic strain increments are always treated as positive in +both tension and compression, and buckling strain also counts towards the +accumulated plastic strain. The material has its full stiffness and strength until the +accumulated plastic strain reaches EPDAM1. Between plastic strains EPDAM1 and +EPDAM2 the stiffness and strength fall linearly with accumulated plastic strain, +reaching a factor DRESID at plastic strain EPDAM2. +Dowel Action: +The data on Card 3 defines the shear stiffness and strength, and is optional. Shear +resistance is assumed to occur by dowel action. The bars bend locally to the crack and +crush the concrete. An elastic-perfectly-plastic relation is assumed for all shear +components (in-plane and through-thickness). The assumed (smeared) shear modulus +and yield stress applicable to the reinforcement bar cross-sectional area are as follows, +based on formulae derived from experimental data by El-Ariss, Soroushian, and +Dulacska: +𝐺[MPa] = 8.02𝐸0.25𝐹𝑐 +0.375𝐿char𝐷𝑏 +0.75 +where, +𝜏𝑦 = 1.62√𝐹𝑐𝑆𝑦 +𝐸 = steel Youngs Modulus in MPa +𝐹𝑐 = 𝑐ompressive strength of concrete in MPa +𝐿char = 𝑐haracteristic length of shear deformation in mm +𝐷𝑏 = bar diameter in mm +𝑆𝑦 = steel yield stress in MPa. +The input parameters should be given in model units, e.g. DBAR and LCHAR are in +model length units, FCDOW is in model stress units. These will be converted internally +using UNITL and UNITC. +Output: +The output stresses, as for all other LS-DYNA material models, are by default in the +global coordinate system. They are scaled by the reinforcement fractions FRACX, +FRACY. The plastic strain output is the accumulated plastic strain (increments always +treated as positive), and is the greater such value of the two local directions. Extra +history variables are available as follows: +Total strain in local 𝑥 direction +Total strain in local 𝑦 direction +Extra variable 1: Reinforcement stress in local 𝑥 direction (not scaled by FRACX) +Extra variable 2: Reinforcement stress in local 𝑦 direction (not scaled by FRACY) +Extra variable 3: +Extra variable 4: +Extra variable 5: Accumulated plastic strain in local 𝑥 direction +Extra variable 6: Accumulated plastic strain in local 𝑦 direction +Extra variable 7: +Extra variable 8: +Extra variable 9: +Shear stress (dowel action) in local 𝑥𝑦 +Shear stress (dowel action) in local 𝑥𝑧 +Shear stress (dowel action) in local 𝑦𝑧 +*MAT_STEEL_EC3 +This is Material Type 202. Tables and formulae from Eurocode 3 are used to derive +the mechanical properties and their variation with temperature, although these can +be overridden by user-defined curves. It is currently available only for Hughes-Liu +beam elements. Warning, this material is still under development and should be +used with caution. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +6 +7 +8 +SIGY +F +Default +none +none +none +none +none + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LC_E +LC_PR +LC_AL +TBL_SS +LC_FS +Type +F +F +F +F +F +Default +none +none +none +none +none +Card 3 must be included but left blank. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +Default + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +VARIABLE +DESCRIPTION +E +PR +SIGY +LC_E +LC_PR +LC_AL +TBL_SS +Young’s modulus – a reasonable value must be provided even if +LC_E is also input. See notes. +Poisson’s ratio. +Initial yield stress, 𝜎𝑦0. +Optional Loadcurve ID: Young’s Modulus vs Temperature +(overrides E and factors from EC3). +Optional Loadcurve +(overrides PR). +ID: Poisson’s Ratio vs Temperature +Optional Loadcurve ID: alpha vs temperature (over-rides thermal +expansion data from EC3). +Optional Table ID containing stress-strain curves at different +temperatures (overrides curves from EC3). +LC_FS +Optional Loadcurve ID: failure strain vs temperature. +Remarks: +1. This material model is intended for modelling structural steel in fires. +2. By default, only E, PR and SIGY have to be defined. Eurocode 3 (EC3) +Section 3.2 specifies the stress-strain behaviour of carbon steels at tempera- +tures between 20C and 1200C. The stress-strain curves given in EC3 are +scaled within the material model such that the maximum stress at low tem- +peratures is SIGY, see graph below. +3. By default, the Young’s Modulus E will be scaled by a factor which is a +function of temperature as specified in EC3. The factor is 1.0 at low temper- +ature. +4. By default, the thermal expansion coefficient as a function of temperature +will be as specified in EC3 Section 3.4.1.1. +5. LC_E, LC_PR and LC_AL are optional; they should have temperature on the +x-axis and the material property on the y-axis, with the points in order of +increasing temperature. If present (i.e. non-zero) they over-ride E, PR, and +the relationships from EC3. However, a reasonable value for E should al- +ways be included, since these values will be used for purposes such as con- +tact stiffness calculation. +6. TBL_SS is optional. If present, TBL_SS must be the ID of a *DEFINE_TA- +BLE. TBL_SS overrides SIGY and the stress-strain relationships from EC3. +The field VALUE on the *DEFINE_TABLE should contain the temperature +at which each stress-strain curve is applicable; the temperatures should be in +ascending order. The curves that follow the temperature values have (true) +plastic strain on the x-axis, (true) yield stress on the y-axis as per other LS- +DYNA elasto-plastic material models. As with all instances of *DEFINE TA- +BLE, the curves containing the stress-strain data must immediately follow +the *DEFINE_TABLE input data and must be in the correct order (i.e. the +same order as the temperatures). +7. Temperature can be defined by any of the *LOAD_THERMAL methods. +The temperature does not have to start at zero: the initial temperature will +be taken as a reference temperature for each element, so non-zero initial +temperatures will not cause thermal shock effects. +Figure M202-1. +*MAT_208 +This is Material Type 208 for use with beam elements using ELFORM = 6 (Discrete +Beam). The beam elements must have nonzero initial length so that the directions in +which tension and compression act can be distinguished. See notes below. + Card 1 +1 +Variable +MID +2 +RO +3 +4 +5 +6 +7 +8 +KAX +KSHR +blank +blank +FPRE +TRAMP +Type +A8 +F +F +F +F +F +Default +none +none +0.0 +0.0 +0.0 +0.0 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCAX +LCSHR +FRIC +CLEAR +DAFAIL +DRFAIL +DAMAG +T0PRE +Type +Default +I +0 +I +0 +F +F +F +F +F +F +0.0 +0.0 +1.E20 +1.E20 +0.1 +0.0 +Card 3 must be included but left blank. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +Default + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +KAX +KSHR +FPRE +DESCRIPTION +Axial elastic stiffness (Force/Length units). +Shear elastic stiffness (Force/Length units). +Preload force. +*MAT_BOLT_BEAM +TRAMP +Time duration during which preload is ramped up. +LCAX +LCSHR +FRIC +CLEAR +DAFAIL +DRFAIL +Load curve giving axial load versus plastic displacement (x- +axis = displacement (length units), y-axis = force). +Load curve ID or table ID giving lateral load versus plastic +displacement (x-axis - displacement (length units), y-axis - force). +In the table case, each curve in the table represents lateral load +versus displacement at a given (current) axial load, i.e. the values +in the table are axial forces. +Friction coefficient resisting sliding of bolt head/nut (non- +dimensional). +Radial clearance (gap between bolt shank and the inner diameter +of the hole) (length units). +Axial tensile displacement at which failure is initiated (length +units). +Radial displacement at which failure is initiated (excludes +clearance). +DAMAG +Failure is completed at (DAFAIL or DRFAIL)*(1+DAMAG). +T0PRE +Time at which preload application begins. +Remarks: +The element represents a bolted joint. The nodes of the beam should be thought of as +representing the points at the centers of the holes in the plates that are joined by the +bolt. It is expected that SCOOR = 0 on *SECTION_BEAM. This is contrary to the +normal rules for non-zero-length discrete beams. +The axial direction is initially the line connecting node 1 to node 2. The axial response is +tensile-only. Instead of generating a compressive axial load, it is assumed that a gap +would develop between the bolt head (or nut) and the surface of the plate. Contact +between the bolted surfaces must be modelled separately, e.g. using *CONTACT. +Curves LCAX, LCSHR give yield force versus plastic displacement for the axial and +shear directions. The force increments are calculated from the elastic stiffnesses, subject +to the yield force limits given by the curves. +CLEAR allows the bolt to slide in shear, resisted by friction between bolt head/nut and +the surfaces of the plates, from the initial position at the center of the hole. CLEAR is +the total sliding shear displacement before contact occurs between the bolt shank and +the inside surface of the hole. Sliding shear displacement is not included in the +displacement used for LCSHR; LCSHR is intended to represent the behaviour after the +bolt shank contacts the edge of the hole. +Output: beam “axial” or “X” force is the axial force in the beam. “shear-Y” and “shear- +Z” are the shear forces. +Other output is written to the d3plot and d3thdt files in the places where post- +processors expect to find the stress and strain at the first two integration points for +integrated beams. +Post-Processing data component +Actual meaning +Int. Pt 1, Axial Stress +Change of length +Int Pt 1, XY Shear stress +Sliding shear displacement in local Y +Int Pt 1, ZX Shear stress +Sliding shear displacement in local Z +Int Pt 1, Plastic strain +Resultant shear sliding displacement +Int Pt 1, Axial strain +Axial plastic displacement +Int. Pt 2, Axial Stress +Int Pt 2, XY Shear stress +Int Pt 2, ZX Shear stress +Int Pt 2, Plastic strain +Int Pt 2, Axial strain +Shear plastic displacement excluding +sliding +- +- +- +- +*MAT_SPR_JLR +This is Material Type 211. This material model was written for Self-Piercing Rivets +(SPR) connecting aluminium sheets. It intended that each SPR is modelled by a single +hexahedral (8-node solid) element, fixed to the sheet either by direct meshing or by tied +contact. Pre- and post-processing methods are the same as for solid-element Spotwelds +using *MAT_SPOTWELD. On *SECTION_SOLID, set ELFORM = 1. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +Default +none +none +none +none +5 +6 +7 +8 +HELAS +TELAS +F +0 +F +0 +Cards 2 and 3 define” Head” end of SPR inputs + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCAXH +LCSHH +LCBMH +SFAXH +SFSHH +SFBMH +Type +F +F +F +Default +none +none +none + Card 3 +1 +2 +3 +F +1 +4 +F +1 +5 +F +1 +6 +Variable +DFAKH +DFSHH +RFBMH DMFAXH DMFSHH DMFBMH +7 +8 +Type +F +F +F +F +F +F +Default +see +notes +see +notes +see +notes +0.1 +0.1 +0.1 +Cards 4 and 5 define “Tail” end of SPR inputs + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCAXT +LCSHT +LCBMT +SFAXT +SFSHT +SBFMT +Type +F +F +F +Default +none +none +none + Card 5 +1 +2 +3 +F +1 +4 +F +1 +5 +F +1 +6 +Variable +DFAXT +DFSHT +RFBMT +DFMAXT DMFSHT DMFBMT +7 +8 +Type +F +F +F +F +F +F +Default +see +notes +see +notes +see +notes +0.1 +0.1 +0.1 + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus, used only for contact stiffness calculation. +Poisson’s ratio, used only for contact stiffness calculation. +HELAS +SPR head end behaviour flag: +EQ.0.0: Nonlinear. +EQ.1.0: Elastic (Use first two points on load curves). +TELAS +SPR tail end behaviour flag: +EQ.0.0: Nonlinear. +EQ.1.0: Elastic (Use first two points on load curves). +LCAXH +Load curve ID, see *DEFINE_CURVE, giving axial force versus +deformation (head). +LCSHH +*MAT_SPR_JLR +DESCRIPTION +Load curve ID, see *DEFINE_CURVE, giving shear force versus +deformation (head). +LCBMH +Load curve ID, see *DEFINE_CURVE, giving moment versus +rotation (head). +SFAXH +Scale factor on axial force from curve LCAXH. +SFSHH +Scale factor on shear force from curve LCSHH. +SFBMH +Scale factor on bending moment from curve LCBMH. +DFAXH +Optional displacement to start of softening in axial load (head). +DFSHH +Optional displacement to start of softening in shear load (head). +RFBMH +Optional rotation (radians) to start of bending moment softening +(head). +DMFAXH +Scale factor on DFAXH. +DMFSHH +Scale factor on FFSHH. +DMFBMH +Scale factor on RFBMH. +LCAXT +LCSHT +LCBMT +Load curve ID, see *DEFINE_CURVE, giving axial force versus +deformation (tail). +Load curve ID, see *DEFINE_CURVE, giving shear force versus +deformation (tail). +Load curve ID, see *DEFINE_CURVE, giving moment versus +rotation (tail). +SFAXT +Scale factor on axial force from curve LCAXT. +SFSHT +Scale factor on shear force from curve LCSHT. +SFBMT +Scale factor on bending moment from curve LCBMT. +DFAXT +Optional displacement to start of softening in axial load (tail). +DFSHT +Optional displacement to start of softening in shear load (tail). +RFBMT +Optional rotation (radians) to start of bending moment softening +(tail). +VARIABLE +DESCRIPTION +DMFAXT +Scale factor on DFAXT. +DMFSHT +Scale factor on FFSHT. +DMFBMT +Scale factor on RFBMT. +Remarks: +1. +“Head” is the end of the SPR that fully perforates a sheet. “Tail” is the end that +is embedded within the thickness of a sheet. +2. E and PR are used only to calculate contact stiffness. They are not used by the +material model. +3. Deformation is in length units and is on the x-axis. Force is on the y-axis. +Rotation is in radians, on the x-axis. Moment is on the y-axis. +4. All the loadcurves are expected to start at (0,0). “Deformation” means the total +deformation including both elastic and plastic components, and similarly for +rotation. +5. A “high tide” algorithm is used to determine the deformation or rotation to be +used as the x-axis of the loadcurves when looking up the current yield force or +moment. The “high tide” is the greatest displacement or rotation that has oc- +curred so far during the analysis. +6. The first two points of the curve define the elastic stiffness, which is used for +unloading. +7. +If HELAS > 0, the remainder of the head loadcurves after the first two points is +ignored and no softening or failure occurs. Similarly for TELAS and the tail +loadcurves. +8. The sheet planes are defined at the head by the quadrilateral defined by nodes +N1-N2-N3-N4 of the solid element; and at the tail by the quadrilateral defined +by nodes N5-N6-N7-N8. +9. The tail of the SPR is defined as a point in the tail sheet plane, initially at the +centre of the element face. The head of the SPR is initially at the centre of the +head sheet plane. Thus the axis of the SPR would typically be coincident with +the solid element local z-axis if the solid is a cuboid. It is the user’s responsibil- +ity to ensure that each solid element is oriented correctly. +10. During the analysis, the head and tail will always remain in the plane of the +sheet, but may move away from the centres of the sheet planes if the shear +forces in these planes are sufficient. +11. The SPR axis is defined as the line joining the tail to the head. +12. Axial deformation is defined as change of length of the line between the tail and +head of the SPR. This line also defines the direction in which the axial force is +applied. +13. Shear deformation is defined as motion of the tail and head points, in the sheet +planes. This deformation is not necessarily perpendicular to axial deformation. +Shear forces in these planes are controlled by the loadcurves LCSHT and +LCSHH. +14. Rotation at the tail is defined as rotation of the tail-to-head line relative to the +normal of the tail sheet plane; and for the head, relative to the normal of the +head sheet plane. +15. Displacement/rotation to start of softening (DFAXH, DFSHH, etc): if non-zero +values are input, these must be within the abcissa values of the relevant curve, +such that the curve force/moment value is greater than zero at the defined start +of softening. +16. Although ELFORM = 1 is used in the input data, *MAT_SPR_JLR is really a +separate unique element formulation. The usual stress/force and hourglass +calculations are bypassed, and deformations and nodal forces are calculated by +a method unique to *MAT_SPR_JLR; for example, a single *MAT_SPR_JLR +element can carry bending loads. +17. *HOURGLASS inputs are irrelevant to *MAT_SPR_JLR. +18. It is essential that the nodes N1 to N4 are fixed to the head sheet (e.g. by direct +meshing or tied contact): the element has no stiffness to resist relative motion of +nodes N1 to N4 in the plane of the head sheet. Similarly, nodes N5 to N8 must +be fixed to the tail sheet. +19. Output to SWFORC file works in the same way as for Spotwelds. Although +inside the material model the loadcurves LCSHT and LCSHH control “shear” +forces in the sheet planes, in the SWFORC file the quoted shear force is the force +normal to the axis of the SPR. +20. Before an element fails, it enters a “softening” regime in which the forces, +moments and stiffnesses are ramped down as displacement increases (this +avoids sudden shocks when the element is deleted). For example, for axial +loading at the head, softening begins when the maximum axial displacement +exceeds DFAXH. As the displacement increases beyond that point, the +loadcurve will be ignored for that deformation component. The forces, mo- +ments and stiffnesses are ramped down linearly with increasing displacement +and reach zero at displacement = DFAXH*(1+DMFAXH) when the element is +deleted. The softening factor scales all the force and moment components at +both head and tail. Thus all the force and moment components are reduced +when any one displacement component enters the softening regime. For exam- +ple if DFAXT = 3.0mm, and DMFAXT = 0.1, then softening begins when axial +displacement of the head reaches 3.0mm and final failure occurs at 3.3mm. +21. If the inputs DFAXT etc are left blank or zero, they will be calculated internally +as follows: +a) Final failure will occur at the displacement or rotation (DFAIL) at which +the loadcurve reaches zero (determined if necessary by extrapolation from +the last two points). +b) Displacement or rotation at which softening begins is then back- +calculated, for example DFAXT = DFAIL/(1+DMGAXT). +c) If DMGAXT was left blank or zero, it defaults to 0.1. +d) If the loadcurve does not drop to zero, and the final two points have a ze- +ro or positive gradient, no failure or softening will be caused by that dis- +placement component. +22. Output stresses (in the d3plot and time-history output files) are set to zero. +23. The output variable “displacement ratio” (or rotation ratio for bending), R, is +defined as follows. See also the Figure M211-1. +a) R = 0 to 1: The maximum force or moment on the input curve has not yet +been reached. R is proportional to the maximum force or moment reached +so far, with 1.0 being the point of maximum force or moment on the input +curve. +b) R = 1 to 2: The element has passed the point of maximum force but has not +yet entered the softening regime. R rises linearly with displacement (or +rotation) from 1.0 when maximum force occurs to 2.0 when softening be- +gins. +c) R = 2 to 3: Softening is occurring. R rises linearly with displacement from +2.0 at the onset of softening to 3.0 when the element is deleted. +Force or +moment +R=1.0 +R=1.0 +R=2.0 +R=3.0 +Linear ramp- +down replaces +the input +loadcurve in +the softening +regime +R=0.0 +DF +DMF +Displacement +or Rotation +Figure [M211-1]. Output variable “displacement ratio” (or rotation ratio for +bending) +24. Displacement (or Rotation) Ratio is calculated separately for axial, shear and +bending at the tail and head . The output +listed by post-processors as “plastic strain” is actually the maximum displace- +ment or rotation ratio of any displacement or rotation component at head or +tail. This same variable is also output as “Failure” in the spotweld data in the +swforc file (or the swforc section of the binout file). +25. Output extra history variables: +1Failure time (used for SWFORC file) +2(Softening factor used internally to prevent abrupt failure) +3Displacement ratio – axial, head +4Displacement ratio – axial, tail +5Displacement ratio – shear, head +6Displacement ratio – shear, tail +7Rotation ratio – bending, head +8Rotation ratio – bending, tail +9(Used for SWFORC output) +10Shear force in “beam” x-axis +11 Shear force in “beam” y-axis +12Axial force in “beam” z-axis (along “beam”) +13Moment about “beam” x-axis at head +14Moment about “beam” y-axis at head +15Moment about “beam” z-axis at head (torsion – should be zero) +16“Beam” length +17Moment about “beam” x-axis at tail +18Moment about “beam” y-axis at tail +19Moment about “beam” z-axis at tail (torsion – should be zero) +20Isoparametric coordinate of head of “beam” (s) +21Isoparametric coordinate of head of “beam” (t) +22Isoparametric coordinate of tail of “beam” (s) +23Isoparametric coordinate of tail of “beam” (t) +24Timestep +25Plastic displacement, axial, head +26Plastic displacement, axial, tail +27Plastic rotation, head +28Plastic rotation, tail +29Plastic displacement, shear in sheet axes, head +30Plastic displacement, shear in sheet axes, tail +31Beam x-axis (global x component) +32Beam x-axis (global y component) +33Beam x-axis (global z component) +34Shear displacement, local x, head +35Shear displacement, local y, head +36Shear displacement, local x, tail +37Shear displacement, local y, tail +38Total displacement – axial +39Current rotation (radians) – head, local X direction +40Current rotation (radians) – head, local Y direction +41Current rotation (radians) – tail, local X direction +42Current rotation (radians) – tail, local Y direction +*MAT_DRY_FABRIC +This is Material Type 214. This material model can be used to model high strength +woven fabrics, such as Kevlar® 49, with transverse orthotropic behavior for use in +structural systems where high energy absorption is required (Bansal et al., Naik et al., +Stahlecker et al.). The major applications of the model are for the materials used in +propulsion engine containment system, body armor and personal protections. +Woven dry fabrics are described in terms of two principal material directions, +longitudinal warp and transverse fill yarns. The primary failure mode in these +materials is the breaking of either transverse or longitudinal yarn. An equivalent +continuum formulation is used and an element is designated as having failed when it +reaches some critical value for strain in either directions. A linearized approximation to +a typical stress-strain curve is shown in Figure M214-1, and to a typical engineering +shear stress-strain curve is shown in the figure corresponding to the GABi field in the +variable list. Note that the principal directions are labeled 𝑎 for the warp and 𝑏 for the +fill, and the direction 𝑐 is orthogonal to 𝑎 and 𝑏. +The material model is available for membrane elements and it is recommended to use a +double precision version of LS-DYNA. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +EA +F +3 +4 +EB +F +4 +Variable +GBC +GCA +GAMAB1 GAMAB2 +F +2 +Type +F + Card 3 +1 +Variable +AOPT +Type +F +F +F +3 +XP +F +4 +YP +F +5 +6 +7 +8 +GAB1 +GAB2 +GAB3 +F +5 +5 +ZP +F +F +6 +6 +A1 +F +F +7 +7 +A2 +F +8 +8 +A3 +Variable +1 +V1 +Type +F + Card 5 +1 +2 +V2 +F +2 +3 +V3 +F +3 +4 +D1 +F +4 +5 +D2 +F +5 +6 +D3 +F +6 +*MAT_214 +7 +8 +BETA +F +7 +8 +Variable +EACRF +EBCRF +EACRP +EBCRP +Type +Remarks +F +2 + Card 6 +1 +F +2 +2 +F +F +3 +4 +5 +6 +7 +8 +Variable +EASF +EBSF +EUNLF +ECOMF +EAMAX +EBMAX +SIGPOST +Type +Remarks +F +2 + Card 7 +1 +F +2 +2 +F +2 +3 +F +2 +4 +F +F +F +5 +6 +7 +8 +Variable +CCE +PCE +CSE +PSE +DFAC +EMAX +EAFAIL +EBFAIL +Type +Remarks +F +1 +F +1 +F +1 +F +1 +F +3 +F +4 +F +4 +F +4 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Continuum equivalent mass density. +SIGPOST +E [ A / B ] C +E C O M P +E[A/B] +[ +/ +] +E[A/B]SF +These strains values +depend on the particular +unloading path. +Pre-peak +linear +behavior +Post-peak +linear +behavior +Crimp +Unloading & +Reloading +Post-peak +non-linear +behavior +[ +/ +] +[ +/ +Strain +] +Failure +Strain +Figure M214-1. Stress – Strain curve for *MAT_DRY_FABRIC. This curve +models the force-response in the longitudinal and transverse directions. + VARIABLE +DESCRIPTION +EA +EB +GABi / +GAMABi +GBC +GCA +AOPT +Modulus of elasticity in the longitudinal (warp) direction, which +corresponds to the slope of segment AB in Figure M214-1. +Modulus of elasticity in the transverse (fill) direction, which +corresponds to the slope of segment of AB Figure M214-1. +Shear stress-strain behavior is +modeled as piecewise linear +in three segments. See the +figure to the right. The shear +moduli GABi correspond to +the slope of the ith segment. +The start and end points for +the segments are specified in +the GAMAB[1-2] fields. +𝐺𝑏𝑐, Shear modulus in 𝑏𝑐 direction. +𝐺𝑐𝑎, Shear modulus in 𝑐𝑎 direction. +G A B 2 +GAB1 +Shear +Strain +Material axes option. See *MAT_OPTIONTROPIC_ELASTIC for a +more complete description: +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the element +normal by an angle BETA. +VARIABLE +DESCRIPTION +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by rotating +the material axes about the element normal by an angle, +BETA, from a line in the plane of the element defined by +the cross product of the vector v with the element nor- +mal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +XP, YP, ZP +Components of vector 𝐱. +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3. +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2. +BETA +EACRF +Material angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA. +Factor for crimp region modulus of elasticity in longitudinal +direction : +𝐸𝑎,crimp = 𝐸𝑎,crimpfac𝐸, +𝐸𝑎,crimpfac = EACRF +EBCRF +Factor for crimp region modulus of elasticity in transverse +direction : +𝐸𝑏,crimp = 𝐸𝑏,crimpfac𝐸, +𝐸𝑏,crimpfac = EBCRF +EACRP +Crimp strain in longitudinal direction : +𝜀𝑎,crimp +EBCRP +Crimp strain in transverse direction : +𝜀𝑏,crimp +EASF +*MAT_DRY_FABRIC +DESCRIPTION +Factor for post-peak region modulus of elasticity in longitudinal +direction : +𝐸𝑎,soft = 𝐸𝑎,softfac𝐸, +𝐸𝑎,softfac = EASF +EBSF +Factor for post-peak region modulus of elasticity in transverse +direction : +𝐸𝑏,soft = 𝐸𝑏,softfac𝐸, +𝐸𝑏,softfac = EBSF +EUNLF +Factor for unloading modulus of elasticity : +𝐸unload = 𝐸unloadfac𝐸, +𝐸unloadfac = EUNLF +ECOMPF +Factor for compression zone modulus of elasticity : +𝐸comp = 𝐸compfac𝐸, +𝐸compfac = ECOMPF +EAMAX +Strain at peak stress in longitudinal direction : +𝜀𝑎,max +EBMAX +Strain at peak stress in transverse direction : +𝜀𝑏,𝑚𝑎𝑥 +SIGPOST +Stress value in post-peak region at which nonlinear behavior +begins : +𝜎post +CCE +PCE +CSE +PSE +Strain rate parameter 𝐶, Cowper-Symonds factor for modulus. If +zero, rate effects are not considered. +Strain rate parameter 𝑃, Cowper-Symonds factor for modulus. If +zero, rate effects are not considered. +Strain rate parameter 𝐶, Cowper-Symonds factor for stress to peak +/ failure. If zero, rate effects are not considered. +Strain rate parameter 𝑃, Cowper-Symonds factor for stress to peak +/ failure. If zero, rate effects are not considered. +DFAC +Damage factor: +𝑑fac +VARIABLE +DESCRIPTION +EMAX +Erosion strain of element: +𝜀max +EAFAIL +Erosion strain in longitudinal direction : +𝜀𝑎,fail +EBFAIL +Erosion strain in transverse direction : +𝜀𝑏,fail +Remarks: +1. Strain rate effects are accounted for using a Cowper-Symonds model which +scales the stress according to the strain rate: +𝛔adj = 𝛔 (1 + +) +. +𝜀̇ +In the above equation 𝛔 is the quasi-static stress, 𝛔adj is the adjusted stress ac- +counting for strain rate 𝜀̇, 𝐶 (CCE) and 𝑃 (PCE) are the Cowper-Symonds factors +and have to be determined experimentally for each material. +The model captures the non-linear strain rate effects in many materials. With +its less than unity exponent, 1/𝑝 , this model captures the rapid increase in +material properties at low strain rate, while increasing less rapidly at very high +strain rates. Because stress is a function of strain rate the elastic stiffness also is: +𝐄adj = 𝐄 (1 + +) +𝜀̇ +where 𝐄adj is the adjusted elastic stiffness. Additionally, the strains to peak and +strains to failure are assumed to follow a Cowper-Symonds model with, possibly +different, constants +𝜀adj = ε (1 + +𝑃𝑠 +) +𝜀̇ +𝐶𝑠 +where, 𝜀adj is the adjusted effective strain to peak stress or strain to failure, and +𝐶𝑠 and 𝑃𝑠 are CSE and PSE respectively. +2. When strained beyond the peak stress, the stress decreases linearly until it +attains a value equal to SIGPOST, at which point the stress-strain relation be- +comes nonlinear. In the non-linear region the stress is given by +𝜎 = 𝜎post +⎢⎡1 − ( +⎣ +𝜀 − 𝜀[𝑎/𝑏],post +𝜀[𝑎/𝑏],fail − 𝜀[𝑎/𝑏],post +) +𝑑fac +⎥⎤ +⎦ +where 𝜎post and 𝜀post are, respectively, the stress and strain demarcating the +onset of nonlinear behavior. The value of SIGPOST is the same in both the +transverse and longitudinal directions, whereas 𝜀a,post and 𝜀b,post depend on +direction and are derived internally from EASF, EBSF, and SIGPOST. The fail- +ure strain, 𝜀[𝑎/𝑏],fail, specifies the onset of failure and differs in the longitudinal +and transverse directions. Lastly the exponent, 𝑑fac, determines the shape of +nonlinear stress-strain curve between 𝜀post and 𝜀[𝑎 𝑏⁄ ],fail. +3. The element is eroded if either (a) or (b) is satisfied: +a) 𝜀𝑎 > 𝜀𝑎,fail and 𝜀𝑏 > 𝜀𝑏,fail +b) 𝜀𝑎 > 𝜀max and 𝜀𝑏 > 𝜀max. +*MAT_215 +This is Material Type 215. A micromechanical material that distinguishes between a +fiber/inclusion and a matrix material, developed by 4a engineering GmbH. It is +available for the explicit code for shell, thick shell and solid elements. Useful hints and +input example can be found in [1]. More theory and application notes will be provided +soon in [2]. +The material is intended for anisotropic composite materials, especially for short (SFRT) +and long fiber thermoplastics (LFRT). The matrix behavior is described by an isotropic +elasto-viscoplastic von Mises model. The fiber/inclusion behavior is transversal +isotropic elastic. This also allows to use this material model for classical endless fiber +composites. +The inelastic homogenization for describing the composite deformation behavior is +based on: +•Mori Tanaka Meanfield Theory [3,4] +•ellipsoidal inclusions using Eshelby´s solution [5,6] +•orientation averaging [7] +•a linear fitted closure approximation to determine the 4th order fiber orientation +tensor out of the user provided 2nd order fiber orientation tensor. +The core functionality to calculate the thermo-elastic composite properties can be also +found in the software product 4a micromec [8]. +Failure/Damage of the composite can be currently considered by +•a ductile damage initiation and evolution model for the matrix (DIEM) +•fiber failure may be considered with a maximum stress criterion. +More details on the material characterization can be found in [9] and [10]. +The (fiber) orientation can be defined either for the whole material using CARD 2 and 3 +or elementwise using *ELEMENT_(T)SHELL_BETA or *ELEMENT_SOLID_ORTHO. +The mechanical properties of SFRT and LFRT in injection molded parts are highly +influenced through the manufacturing process. By mapping the fiber orientation from +the process simulation to the structural analysis the local anisotropy can be considered +[11,12]. The fiber orientation, length and volume fraction can therefore as well be +defined for each integration point by using *INITIAL_STRESS_(T)SHELL(SOLID) [2]. +Details on the history variables that can be initialized (Extravars. 9-18) can be found in +the output section. +*MAT_4A_MICROMEC + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +MMOPT +BUPD +FAILM +FAILF +NUMINT +Type +A8 +F +F +F +F +F +Default +none +0.0 +0.01 +0.0 +0.0 +1.0 +Parameter for fiber orientation (may be overwritten by +*INITIAL_STRESS_SHELL/SOLID) + Card 2 +1 +2 +Variable +AOPT +MACF +Type +F +Default +0.0 + Card 3 +Variable +1 +V1 +Type +F +F +0 +2 +V2 +F +3 +XP +F +4 +YP +F +5 +ZP +F +6 +A1 +F +7 +A2 +F +8 +A3 +F +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +BETA +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +1 +2 +Variable +FVF +Type +F +3 +FL +F +4 +FD +F +*MAT_215 +5 +6 +7 +8 +A11 +A22 +F +F +Default +0.0 +0.0 +1.0 +1.0 +0.0 +Parameter for fiber/inclusion material + Card 5 +1 +Variable +ROF +Type +F +2 +EL +F +3 +ET +F +4 +5 +6 +7 +8 +GLT +PRTL +PRTT +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +2 +3 +4 +5 +6 +7 +8 + Card 6 +Variable +1 +XT +Type +F +Default +0.0 +Parameter for matrix material + Card 7 +1 +Variable +ROM +Type +F +2 +E +F +3 +PR +F +Default +0.0 +0.0 +0.0 +SLIMXT +NCYRED +F +F +0.0 +10 +4 +5 +6 +7 +Card 8 +1 +2 +3 +4 +5 +Variable +SIGYT +ETANT +Type +F +F +EPS0 +F +6 +C +F +7 +8 +Default +0.0 +0.0 +0.0 +0.0 + Card 9 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCIDT +LCDI +UPF +Type +Default +F +0 + VARIABLE +MID +F +0 +F +0.0 +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +MMOPT +Option to define micromechanical material behavior +EQ.0.0: elastic +EQ.1.0: elastic-plastic +BUPD +Tolerance for update of Strain-Concentration Tensor +VARIABLE +FAILM +DESCRIPTION +Opion for matrix failure – ductile DIEM-Model. + based on +stress triaxiality and a linear damage evolution (DETYP.EQ.0) +type) +LT.0: |FAILM| Effective plastic matrix strain at failure. When +the matrix plastic strain reaches this value, the element is +deleted from the calculation. +EQ.0: only visualization (triaxiality of matrix stresses) +EQ.1: active DIEM (triaxiality of matrix stresses) +EQ.10: only visualization (triaxiality of composite stresses) +EQ.11: active DIEM (triaxiality of composite stresses) +FAILF +Option for fiber failure +EQ.0: only visualization (equivalent fiber stresses) +EQ.1: active (equivalent fiber stresses) +NUMINT +Number of failed integration points prior to element deletion. +LT.0.0: Only for shells. |NUMINT| is the percentage of +integration points which must exceed the failure criterion +before element fails. For shell formulations with 4 inte- +gration points per layer, the layer is considered failed if +any of the integration points in the layer fails. + Parameter for fiber orientation +AOPT +See *MAT_002 (fiber orientation information may be overwritten +using *INITIAL_STRESS_(T)SHELL/SOLID) +MACF +Material axes change flag for solid elements: +EQ.1: No change, default, +EQ.2: switch material axes a and b, +EQ.3: switch material axes a and c, +EQ.4: switch material axes b and c. +XP, YP, ZP +Define coordinates of point p for AOPT = 1 and 4. +A1, A2, A3 +Define components of vector a for AOPT = 2. +*MAT_4A_MICROMEC +DESCRIPTION +V1, V2, V3 +Define components of vector v for AOPT = 3 and 4. +D1, D2, D3 +Define components of vector d for AOPT = 2. +BETA +Material angle in degrees for AOPT = 3, may be overwritten on +the element card, see +*ELEMENT_(T)SHELL_BETA or *ELEMENT_SOLID_ORTHO. +FVF +Fiber-Volume-Fraction +GT.0: Fiber-Volume-Fraction +LT.0: |FVF| Fiber-Mass-Fraction +FL +FD +A11 +A22 +Fiber length - if FD = 1 then FL = aspect ratio (may be overwritten +by *INITIAL_STRESS_(T)SHELL/SOLID) +Fiber diameter (may be overwritten by +*INITIAL_STRESS_(T)SHELL/SOLID) +Value of first principal fiber orientation (may be overwritten by +*INITIAL_STRESS_(T)SHELL/SOLID). +Value of second principal fiber orientation (may be overwritten +by *INITIAL_STRESS_(T)SHELL/SOLID). +Parameter for fiber/inclusion material +ROF +Mass density of fiber +EL +ET +GLT +PRTL +PRTT +XT +EL, Young’s modulus of fiber – longitudinal direction. +ET, Young’s modulus of fiber – transverse direction. +GLT, Shear modulus LT + TL, Poisson’s ratio TL + TT, Poisson’s ratio TT +Fiber tensile strength – longitudinal direction. +SLIMXT +Factor to determine the minimum stress limit in the fiber after +stress maximum (fiber tension) +NCYRED +Number of cycles for stress reduction from maximum to +minimum (fiber tension) +Parameter for matrix material +ROM +Mass density of matrix. +E +PR +SIGYT +ETANT +EPS0 +C +LCIDT +Young’s modulus of matrix. +Poisson’s ratio of matrix. +Yield stress of matrix in tension +Tangent modulus of matrix in tension, ignore if (LCST.GT.0.) is +defined. +Quasi-static threshold strain rate (Johnson-Cook model) for bi- +linear hardening +Johnson-Cook constant for bi-linear hardening +Load curve ID or Table ID for defining effective stress versus +effective plastic strain in tension of matrix material (Table to +include strain-rate effects, viscoplastic formulation) +LCDI +Damage initiation parameter (ductile) +shells: Load curve ID representing plastic strain at onset of +damage as function of stress triaxiality. +or +Table ID representing plastic strain at onset of damage as +function of stress triaxiality and plastic strain rate. +solids: Load curve ID representing plastic strain at onset of +damage as function of stress triaxiality. +or +Table ID representing plastic strain at onset of damage as +function of stress triaxiality and lode angle. +or +Table3D ID representing plastic strain at onset of damage +as function of stress triaxiality, lode angle and plastic +strain rate. +UPF +Damage evolution parameter +𝑝 +GT.0.0: plastic displacement at failure, 𝑢𝑓 +LT.0.0: |UPF| is a table ID for 𝑢𝑓 +𝑝 as a function of triaxiality and + damage +Output: +“Plastic Strain” is the equivalent plastic strain in the matrix. +Extra history variables may be requested for (t)shell (NEIPS) and solid (NEIPH) +elements on *DATABASE_EXTENT_BINARY. Extra history variables 1-8 are +intended for post processing, 9-18 for initialization with +*INITIAL_STRESS_(T)SHELL/SOLID. They have the following meaning: + Extravar. +DESCRIPTION +1 +2 +3 +4 +5 +6 +7 +8 +effs - equivalent plastic strain rate of matrix +eta - triaxiality of matrix ...  = − +q +xi - lode parameter of matrix ...  = − +27∙J3 +2∙q +dM - Damage initiation d of matrix (Ductile Criteria) +DM - Damage evolution D of matrix +RFF - Fiber reserve factor +DF- Fiber damage variable +Currently unused + Extravar. +DESCRIPTION +9 +10 +11 +12 +13 +14 +15 +16 +A11 - fiber orientation first principal value +A22 - fiber orientation first second value +q1/q11 +q2/q12 +-/q13 +-/q31 +-/q32 +-/q33 +17 +18 +FVF- Fiber-Volume-Fraction +FL- Fiber length +References: + [1] Reithofer, P., et. al, *MAT_4A_MICROMEC – micro mechanic based material model, 14th German +LS-DYNA Conference (2016), Bamberg + [2] Reithofer, P., et. al, *MAT_4A_MICROMEC – Theory and application notes, 11th European LS- +DYNA Conference (2017), Salzburg + [3] Mori, T., Tanaka, K., Average Stress in Matrix and Average elastic Energy of Materials with +misfitting Inclusions, Acta Metallurgica, Vol.21, pp.571-574, (1973). + [4] Tucker Ch. L. III, Liang Erwin: Stiffness Predictions for Unidirectional Short-Fibre Composites: +Review and Evaluation, Composites Science and Technology, 59, (1999) + [5] Maewal A., Dandekar D.P.: Effective Thermoelastic Properties of Short-Fibre Composites, Acta +Mechanica, 66, (1987) + [6] Eshelby, J. D., The determination of the elastic field of an ellipsoidal inclusion, and related +problems, Proceedings of the Royal Society, London, Vol.A, No241, pp.376-396, (1957). + [7] Mlekusch, B., Kurzfaserverstärkte Thermoplaste, Dissertation, Montanuniversität Leoben (1997) + [8] http://micromec.4a.co.at + [9] Reithofer, P. et. al: Material characterization of composites using micro mechanic models as key +enabler, NAFEMS DACH, Bamberg 2016 +[10] http://impetus.4a.co.at +[11] Reithofer, P. et. al: Short and long fiber reinforced thermoplastics material models in LS-DYNA, +10th European LS-DYNA Conference, Würzburg 2015 +[12] http://fibermap.4a.co.at +*MAT_ELASTIC_PHASE_CHANGE +This is Material Type 216, a generalization of Material Type 1, for which material +properties change on an element-by-element basis upon crossing a plane in space. This +is an isotropic hypoelastic material and is available only for shell element types. +5 +6 +7 +8 +5 +6 +7 +8 +Phase 1 Properties. + Card 1 +1 +2 +Variable +MID +RO1 +Type +A8 +F +3 +E1 +F +4 +PR1 +F +Default +none +none +none +0.0 +Phase 2 Properties. + Card 1 +1 +2 +Variable +Type +RO2 +F +3 +E2 +F +4 +PR2 +F +Default +none +none +0.0 +Transformation Plane Card. + Card 2 +Variable +1 +X1 +Type +F +2 +Y1 +F +3 +Z1 +F +4 +X2 +F +5 +Y2 +F +6 +Z2 +F +7 +8 +THKFAC +F +Default +none +none +none +none +none +none +1.0 +VARIABLE +DESCRIPTION +MID +ROi +Ei +PRi +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density for phase i. +Young’s modulus for phase i. +Poisson’s ratio for phase i. +X1, Y1, Z1 +Coordinates of a point on the phase transition plane. +Coordinates of a point that defines the exterior normal with the +first point. +Scale factor applied to the shell thickness after the phase +transformation. +X2, Y2, Z2 +THKFAC +Phases: +The material properties for each element are initialized using the data for the first +phase. After the center of the element passes through the transition plane defined by +the two points, the material properties are irreversibly changed to the second phase. +The plane is defined by two points. The first point, defined by the coordinates X1, Y1, +and Z1, lies on the plane. The second point, defined by the coordinates X2, Y2, and Z2, +define the exterior normal as a unit vector in the direction from the first point to the +second point. +Remarks: +This hypoelastic material model may not be stable for finite (large) strains. If large +strains are expected, a hyperelastic material model, e.g., *MAT_002 or *MAT_217, +would be more appropriate. +*MAT_OPTIONTROPIC_ELASTIC_PHASE_CHANGE +This is Material Type 217 a generalization of Material Type 2 for which material +properties change on an element-by-element basis upon crossing a plane in space. +This material is valid only for shells. The stress update is incremental and the elastic +constants are formulated in terms of Cauchy stress and true strain. +Available options include: +ORTHO +ANISO +such that the keyword cards appear: +*MAT_ORTHOTROPIC_ELASTIC_PHASE_CHANGE or MAT_217 +(9 cards follow) +*MAT_ANISOTROPIC_ELASTIC_PHASE_CHANGE or MAT_217_ANIS +(11 cards follow) +Orthotropic Card 1 (phase 1). Card 1 for ORTHO keyword option for phase 1. + Card 1 +1 +2 +Variable +MID +RO1 +Type +A8 +F +3 +EA +F +4 +EB +F +5 +EC +F +6 +7 +8 +PRBA +PRCA +PRCB +F +F +F +Orthotropic Card 2 (phase 1). Card 2 for ORTHO keyword option for phase 1. + Card 2 +1 +2 +3 +4 +Variable +GAB +GBC +GCA +AOPT1 +Type +F +F +F +F +5 +G +F +6 +7 +8 +SIGF +Anisotropic Card 1 (phase 1). Card 1 for ANISO keyword option for phase 1. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +RO2 +C111 +C121 +C221 +C131 +C231 +C331 +Type +A8 +F +F +F +F +F +F +F +Anisotropic Card 2 (phase 1). Card 2 for ANISO keyword option for phase 1. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +C141 +C241 +C341 +C441 +C151 +C251 +C351 +C451 +Type +F +F +F +F +F +F +F +F +Anisotropic Card 3 (phase 1). Card 3 for ANISO keyword option for phase 1. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +C551 +C161 +C261 +C361 +C461 +C561 +C661 +AOPT1 +Type +F +F +F +F +F +F +F +F +Local Coordinate System Card 1 (phase 1). Required for all keyword options + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +XP1 +YP1 +ZP1 +A11 +A21 +A31 +MACF +IHIS +Type +F +F +F +F +F +F +I +F +Local Coordinate System Card 2 (phase 1). Required for all keyword options + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +V11 +V21 +V31 +D11 +D21 +D31 +BETA1 +REF +Type +F +F +F +F +F +F +F +Orthotropic Card 3 (phase 2). Card 1 for ORTHO keyword option phase 2. + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +EA2 +EB2 +EC2 +PRBA2 +PRCA2 +PRCB2 +F +F +F +F +F +F +Orthotropic Card 4 (phase 2). Card 2 for ORTHO keyword option phase 2. + Card 7 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +GAB2 +GBC2 +GCA2 +Type +F +F +F +Anisotropic Card 4 (phase 2). Card 1 for ANISO keyword option for phase 2. + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +C112 +C122 +C222 +C132 +C232 +C332 +F +F +F +F +F +F +Anisotropic Card 5 (phase 2). Card 2 for ANISO keyword option for phase 2. + Card 7 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +C142 +C242 +C342 +C442 +C152 +C252 +C352 +C452 +Type +F +F +F +F +F +F +F +Anisotropic Card 6 (phase 2). Card 3 for ANISO keyword option for phase 2. + Card 8 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +C552 +C162 +C262 +C362 +C462 +C562 +C662 +Type +F +F +F +F +F +F +F +Local Coordinate System Card 1 (phase 2). Required for all keyword options + Card 9 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +XP2 +YP2 +ZP2 +A12 +A22 +A32 +MACF2 +Type +F +F +F +F +F +F +I +Local Coordinate System Card 2 (phase 2). Required for all keyword options + Card 10 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +V12 +V22 +V32 +D12 +D22 +D32 +BETA2 +Type +F +F +F +F +F +F +F +Definition of transformation plane Card. + Card 11 +Variable +1 +X1 +Type +F +2 +Y1 +F +3 +Z1 +F +4 +X2 +F +5 +Y2 +F +6 +Z2 +F +7 +8 +THKFAC +F +Default +none +none +none +none +none +none +1.0 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +ROi +Mass density for phase i. +Define for the ORTHO option only: +EAi +EBi +ECi +PRBAi +PRCAi +PRCBi +GABi +GBCi +GCAi +𝐸𝑎, Young’s modulus in 𝑎-direction for phase i. +𝐸𝑏, Young’s modulus in 𝑏-direction for phase i. +𝐸𝑐, Young’s modulus in 𝑐-direction phase i (nonzero value +required but not used for shells). +𝜈𝑏𝑎, Poisson’s ratio in the 𝑏𝑎 direction for phase i. +𝜈𝑐𝑎, Poisson’s ratio in the ca direction for phase i. +𝜈𝑐𝑏, Poisson’s ratio in the 𝑐𝑏 direction for phase i. +𝐺𝑎𝑏, shear modulus in the ab direction for phase i. +𝐺𝑏𝑐, shear modulus in the 𝑏𝑐 direction for phase i. +𝐺𝑐𝑎, shear modulus in the 𝑐𝑎 direction for phase i. +Due to symmetry define the upper triangular Cij’s for the ANISO option only: +C11i +C12i +⋮ +C66i +The 1,1 term in the 6 × 6 anisotropic constitutive matrix for phase +i. Note that 1 corresponds to the 𝑎 material direction +The 1,2 term in the 6 × 6 anisotropic constitutive matrix for phase +i. Note that 2 corresponds to the 𝑏 material direction +⋮ +The 6,6 term in the 6 × 6 anisotropic constitutive matrix for phase +i. +Define AOPT for both options: +AOPTi +Material axes option for phase i, see Figure M2-1. +EQ.0.0: locally orthotropic with material axes determined by +element nodes as shown in part (a) of Figure M2-1. +The a-direction is from node 1 to node 2 of the element. +The b-direction is orthogonal to the a-direction and is +in the plane formed by nodes 1, 2, and 4. When this +option is used in two-dimensional planar and axisym- +metric analysis, it is critical that the nodes in the ele- +ment definition be numbered counterclockwise for this +option to work correctly. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the 𝐚-direction. This option is for solid +elements only. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector 𝐯 with the +element normal. The plane of a solid element is the +midsurface between the inner surface and outer surface +defined by the first four nodes and the last four nodes +of the connectivity of the element, respectively. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector 𝐯, and +an originating point, 𝐏, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +G +Shear modulus for frequency independent damping. Frequency +independent damping is based of a spring and slider in series. +The critical stress for the slider mechanism is SIGF defined below. +For the best results, the value of G should be 250-1000 times +greater than SIGF. This option applies only to solid elements. +SIGF +Limit stress for frequency independent, frictional, damping. +XPi, YPi, ZPi +Define coordinates of the ith phase’s point 𝐩 for AOPT = 1 and 4. +A1i, A2i, A3i +Define components of the ith phase’s vector 𝐚 for AOPT = 2. +MACFi +Material axes change flag for brick elements in phase i: +EQ.1: No change, default, +EQ.2: switch material axes 𝑎 and 𝑏, +EQ.3: switch material axes 𝑎 and 𝑐, +EQ.4: switch material axes 𝑏 and 𝑐. +IHIS +Flag for anisotropic stiffness terms initialization (for solid +elements only). +EQ.0: C11, C12, … from Cards 1, 2, and 3 are used. +EQ.1: C11, C12, … are initialized by *INITIAL_STRESS_SOL- +ID’s history data. +V1i, V2i, V3i +Define components of the ith phase’s vector 𝐯 for AOPT = 3 and 4. +D1i, D2i, D3i +Define components of the ith phase’s vector 𝐝 for AOPT = 2. +BETAi +REFi +Material angle of ith phase in degrees for AOPT = 3, may be +overridden on the element card, see *ELEMENT_SHELL_BETA +or *ELEMENT_SOLID_ORTHO. +Use reference geometry to initialize the stress tensor for the ith +phase. The reference geometry is defined by the keyword: *INI- +TIAL_FOAM_REFERENCE_GEOMETRY . +EQ.0.0: off, +EQ.1.0: on. +X1, Y1, Z1 +Coordinates of a point on the phase transition page. +Coordinates of a point that defines the exterior normal with the +first point. +Scale factor applied to the shell thickness after the phase +transformation. +X2, Y2, Z2 +THKFAC +Phases: +The material properties for each element are initialized using the data for the first +phase. After the center of the element passes through the transition plane defined by +the two points, the material properties are irreversibly changed to the second phase. +The plane is defined by two points. The first point, defined by the coordinates X1, Y1, +and Z1, lies on the plane. The second point, defined by the coordinates X2, Y2, and Z2, +define the exterior normal as a unit vector in the direction from the first point to the +second point. +Material Formulation: +The material law that relates stresses to strains is defined as: +𝐂 = 𝐓T𝐂𝐿𝐓 +where 𝐓 is a transformation matrix, and 𝐂𝐿 is the constitutive matrix defined in terms of +the material constants of the orthogonal material axes, {𝐚, 𝐛, 𝐜}. The inverse of 𝐂𝐿for +the orthotropic case is defined as: +−1 = +𝐂𝐿 +𝐸𝑎 +𝜐𝑎𝑏 +𝐸𝑎 +𝜐𝑎𝑐 +𝐸𝑎 +− +− +− +− +𝜐𝑏𝑎 +𝐸𝑏 +𝐸𝑏 +𝜐𝑏𝑐 +𝐸𝑏 +− +− +𝜐𝑐𝑎 +𝐸𝑐 +𝜐𝑐𝑏 +𝐸𝑐 +𝐸𝑐 +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +𝐺𝑎𝑏 +𝐺𝑏𝑐 +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +𝐺𝑐𝑎⎦ +Where, +𝜐𝑎𝑏 +𝐸𝑎 += +𝜐𝑏𝑎 +𝐸𝑏 +, +𝜐𝑐𝑎 +𝐸𝑐 += +𝜐𝑎𝑐 +𝐸𝑎 +, +𝜐𝑐𝑏 +𝐸𝑐 += +𝜐𝑏𝑐 +𝐸𝑏 +. +The frequency independent damping is obtained by having a spring and slider in series +as shown in the following sketch: +friction +This option applies only to orthotropic solid elements and affects only the deviatoric +stresses. +The procedure for describing the principle material directions is explained for solid and +shell elements for this material model and other anisotropic materials. We will call the +material direction the {𝐚, 𝐛, 𝐜} coordinate system. The AOPT options illustrated in +Figure M2-1 can define the {𝐚, 𝐛, 𝐜} system for all elements of the parts that use the +material, but this is not the final material direction. There {𝐚, 𝐛, 𝐜} system defined by the +AOPT options may be offset by a final rotation about the 𝐜-axis. The offset angle we call +BETA. +For solid elements, the BETA angle is specified in one of two ways. When using +AOPT = 3, the BETA parameter defines the offset angle for all elements that use the +material. The BETA parameter has no meaning for the other AOPT options. +Alternatively, a BETA angle can be defined for individual solid elements as described in +remark 5 for *ELEMENT_SOLID_ORTHO. The beta angle by the ORTHO option is +available for all values of AOPT, and it overrides the BETA angle on the *MAT card for +AOPT = 3. +The directions determined by the material AOPT options may be overridden for +individual elements as described in remark 3 for *ELEMENT_SOLID_ORTHO. +However, be aware that for materials with AOPT = 3, the final {𝐚, 𝐛, 𝐜} system will be +the system defined on the element card rotated about 𝐜-axis by the BETA angle +specified on the *MAT card. +There are two fundamental differences between shell and solid element orthotropic +materials. First, the 𝐜-direction is always normal to a shell element such that the 𝐚- +direction and 𝐛-directions are within the plane of the element. Second, for some +anisotropic materials, shell elements may have unique fiber directions within each layer +through the thickness of the element so that a layered composite can be modeled with a +single element. +When AOPT = 0 is used in two-dimensional planar and axisymmetric analysis, it is +critical that the nodes in the element definition be numbered counterclockwise for this +option to work correctly. +Because shell elements have their 𝐜-axes defined by the element normal, AOPT = 1 and +AOPT = 4 are not available for shells. Also, AOPT = 2 requires only the vector 𝐚 be +defined since 𝐝 is not used. The shell procedure projects the inputted 𝐚-direction onto +each element surface. +Similar to solid elements, the {𝐚, 𝐛, 𝐜} coordinate system determined by AOPT is then +modified by a rotation about the 𝐜-axis which we will call 𝜙. For those materials that +allow a unique rotation angle for each integration point through the element thickness, +the rotation angle is calculated by +𝜙𝑖 = 𝛽 + 𝛽𝑖 +where 𝛽 is a rotation for the element, and 𝛽𝑖 is the rotation for the i’th layer of the +element. The 𝛽 angle can be input using the BETA parameter on the *MAT data, or will +be overridden for individual elements if the BETA keyword option for *ELEMENT_- +SHELL is used. The 𝛽𝑖 angles are input using the ICOMP = 1 option of *SECTION_- +SHELL or with *PART_COMPOSITE. If 𝛽 or 𝛽𝑖 is omitted, they are assumed to be zero. +All anisotropic shell materials have the BETA option on the *MAT card available for +both AOPT = 0 and AOPT = 3, except for materials 91 and 92 which have it available for +all values of AOPT, 0, 2, and 3. +All anisotropic shell materials allow an angle for each integration point through the +thickness, 𝛽𝑖, except for materials 2, 86, 91, 92, 117, 130, 170, 172, and 194. +This discussion of material direction angles in shell elements also applies to thick shell +elements which allow modeling of layered composites using *INTEGRATION_SHELL +or *PART_COMPOSITE_TSHELL. +*MAT_MOONEY-RIVLIN_PHASE_CHANGE +This is Material Type 218, a generalization of Material Type 27, for which material +properties change on an element-by-element basis upon crossing a plane in space. +Phase 1 Card 1. + Card 1 +1 +2 +3 +Variable +MID +RO1 +PR1 +Type +A8 +F +F +4 +A1 +F +5 +B1 +F +6 +REF +F +7 +8 +Phase 1 Card 2. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SGL1 +SW1 +ST1 +LCID1 +Type +F +F +F +F +Phase 2 Card 1. + Card 3 +1 +2 +3 +Variable +RO2 +PR2 +Type +F +F +4 +A2 +F +5 +B2 +F +6 +7 +8 +Phase 2 Card 2. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SGL2 +SW2 +ST2 +LCID2 +Type +F +F +F +Transformation Plane Card. + Card 5 +Variable +1 +X1 +Type +F +2 +Y1 +F +3 +Z1 +F +4 +X2 +F +5 +Y2 +F +6 +Z2 +F +7 +8 +THKFAC +F +Default +none +none +none +none +none +none +1.0 + VARIABLE +DESCRIPTION +MID +ROi +PRi +Ai +Bi +REF +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density for phase i. +Poisson’s ratio (value between 0.49 and 0.5 is recommended, +smaller values may not work) where i indicates the phase. +Constant for the ith phase, see literature and equations defined +below. +Constant for the ith phase, see literature and equations defined +below. +Use reference geometry to initialize the stress tensor. The +reference geometry is defined by the keyword:*INITIAL_FOAM_- +REFERENCE_GEOMETRY . +EQ.0.0: off, +EQ.1.0: on. +gauge +length +Force +AA +Δ gauge length +Section AA +thickness +width +Figure M218-1. Uniaxial specimen for experimental data +If A = B = 0.0, then a least square fit is computed from tabulated uniaxial data via a +load curve. The following information should be defined: + VARIABLE +DESCRIPTION +SGLi +SWi +STi +LCIDi +Specimen gauge length 𝑙0 for the ith phase, see Figure M218-1. +Specimen width for the ith phase, see Figure M218-1. +Specimen thickness for the ith phase, see Figure M218-1. +Curve ID for the ith phase, see *DEFINE_CURVE, giving the force +versus actual change Δ𝐿 in the gauge length. See also Figure +M218-2 for an alternative definition. +X1, Y1, Z1 +Coordinates of a point on the phase transition plane. +X2, Y2, Z2 +THKFAC +Coordinates of a point that defines the exterior normal with the +first point. +Scale factor applied to the shell thickness after the phase +transformation. +Phases: +The material properties for each element are initialized using the data for the first +phase. After the center of the element passes through the transition plane defined by +the two points, the material properties are irreversibly changed to the second phase. +The plane is defined by two points. The first point, defined by the coordinates X1, Y1, +and Z1, lies on the plane. The second point, defined by the coordinates X2, Y2, and Z2, +define the exterior normal as a unit vector in the direction from the first point to the +second point. +Material Formulation: +The strain energy density function is defined as: +𝑊 = 𝐴(𝐼 − 3) + 𝐵(𝐼𝐼 − 3) + 𝐶(𝐼𝐼𝐼−2 − 1) + 𝐷(𝐼𝐼𝐼 − 1)2 +where +𝐶 = 0.5 𝐴 + 𝐵 +𝐷 = +𝐴(5𝜐 − 2) + 𝐵(11𝜐 − 5) +2(1 − 2𝜐) +𝜈 = Poisson’s ratio +2(𝐴 + 𝐵) = shear modulus of linear elasticity +𝐼, 𝐼𝐼, 𝐼𝐼𝐼 = invariants of right Cauchy-Green Tensor C. +The load curve definition that provides the uniaxial data should give the change in +gauge length, Δ𝐿, versus the corresponding force. In compression both the force and +the change in gauge length must be specified as negative values. In tension the force +and change in gauge length should be input as positive values. The principal stretch +ratio in the uniaxial direction, 𝜆1, is then given by +𝐿0 + Δ𝐿 +𝐿0 +𝜆1 = +with 𝐿0 being the initial length and 𝐿 being the actual length. +applied force +initial area += +A0 +change in gauge length +gauge length += +∆L +Figure M218-2 The stress versus strain curve can used instead of the force +versus the change in the gauge length by setting the gauge length, thickness, +and width to unity (1.0) and defining the engineering strain in place of the +change in gauge length and the nominal (engineering) stress in place of the +force. *MAT_077_O is a better alternative for fitting data resembling the curve +above. *MAT_027 will provide a poor fit to a curve that exhibits a strong +upturn in slope as strains become large. +Alternatively, the stress versus strain curve can also be input by setting the gauge +length, thickness, and width to unity (1.0) and defining the engineering strain in place +of the change in gauge length and the nominal (engineering) stress in place of the force, +see Figure M218-1. +The least square fit to the experimental data is performed during the initialization phase +and is a comparison between the fit and the actual input is provided in the d3hsp file. +It is a good idea to visually check to make sure it is acceptable. The coefficients 𝐴 and 𝐵 +are also printed in the output file. It is also advised to use the material driver for checking out the material model. +*MAT_219 +This is material type 219. This material model is the second generation of the UBC +Composite Damage Model (CODAM2) for brick, shell, and thick shell elements +developed at The University of British Columbia. The model is a sub-laminate-based +continuum damage mechanics model for fiber reinforced composite laminates made up +of transversely isotropic layers. The material model includes an optional non-local +averaging and element erosion. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +EA +F +4 +EB +F +5 +6 +7 +8 +PRBA +PRCB +F +F +Default +none +none +none +none +none +none + Card 2 +1 +2 +3 +4 +5 +Variable +GAB +NLAYER +R1 +Type +F +Default +none + Card 3 +Variable +1 +XP +Type +F +2 +YP +F +3 +ZP +F +I +0 +4 +A1 +F +6 +R2 +F +F +0.0 +0.0 +5 +A2 +F +6 +A3 +F +7 +8 +NFREQ +I +0 +7 +AOPT +I +0 +8 +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +*MAT_CODAM2 +7 +8 +BETA +MACF +F +I +0 +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Angle Cards. For each of the NLAYER layers specify on angle. Include as many cards +as needed to set NLAYER values. + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ANGLE1 +ANGLE2 +ANGLE3 +ANGLE4 +ANGLE5 +ANGLE6 +ANGLE7 +ANGLE8 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IMATT +IFIBT +ILOCT +IDELT +SMATT +SFIBT +SLOCT +SDELT +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none + Card 7 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IMATC +IFIBC +ILOCC +IDELC +SMATC +SFIBC +SLOCC +SDELC +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +Card 8 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ERODE +ERPAR1 +ERPAR2 +RESIDS +Type +Default +I +0 +F +F +none +none +F +0 + VARIABLE +DESCRIPTION +MID +RO +EA +EB +PRBA +PRCB +GAB +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +𝐸𝑎, Young’s modulus in 𝑎-direction. This is the modulus along +the direction of fibers. +𝐸𝑏, Young’s modulus in 𝑏-direction. This is the modulus +transverse to fibers. +𝜈𝑏𝑎, Poisson’s ratio, 𝑏𝑎 (minor in-plane Poisson’s ratio). +𝜈𝑐𝑏, Poisson’s ratio, 𝑐𝑏 (Poisson’s ratio in the plane of isotropy). +𝐺𝑏𝑎, Shear modulus, 𝑎𝑏 (in-plane shear modulus). +NLAYER +Number of layers in the sub-laminate excluding symmetry. As an +example, in a [0/45/-45/90]3s, NLAYER = 4. +R1 +R2 +NFREQ +Non-local averaging radius. +Currently not used. +Number of time steps between update of neighbor list for +nonlocal smoothing. +EQ.0: Do only one search at the start of the calculation +XP, YP, ZP +Coordinates of point 𝐩 for AOPT = 1 and 4. +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +AOPT +*MAT_CODAM2 +DESCRIPTION +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then, for shells only, rotated about +the shell element normal by an angle BETA. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the 𝑎-direction. This option is for solid +elements only. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector 𝐯 with the +element normal. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector 𝐯, and +an originating point, 𝐩, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). +V1, V2, V3 +Components of vector v for AOPT = 3 and 4. +D1, D2, D3 +Components of vector d for AOPT = 2. +BETA +Material angle in degrees for AOPT = 0 (shells only) and +AOPT = 3. BETA be overridden on the element card, see *ELE- +MENT_SHELL_BETA or *ELEMENT_SOLID_ORTHO. +VARIABLE +DESCRIPTION +MACF +Material axes change flag for brick elements: +EQ.1: No change, default, +EQ.2: switch material axes 𝑎 and 𝑏, +EQ.3: switch material axes 𝑎 and 𝑐, +EQ.4: switch material axes 𝑏 and 𝑐. +ANGLEi +Rotation angle in degrees of layers with respect to the material +axes. Input one for each layer. +IMATT +IFIBT +ILOCT +IDELT +SMATT +SFIBT +SLOCT +SDELT +IMATC +IFIBC +Initiation strain for damage in matrix (transverse) under tensile +condition. +Initiation strain for damage in the fiber (longitudinal) under +tensile condition. +Initiation strain for the anti-locking mechanism. This parameter +should be equal to the saturation strain for the fiber damage +mechanism under tensile condition. +Not working in the current version. Can be used for visualization +purpose only. +Saturation strain for damage in matrix (transverse) under tensile +condition. +Saturation strain for damage in the fiber (longitudinal) under +tensile condition. +Saturation strain for the anti-locking mechanism under tensile +condition. + The recommended value for this parameter is +(ILOCT+0.02). +Not working in the current version. Can be used for visualization +purpose only. +Initiation strain for damage +compressive condition. +in matrix (transverse) under +Initiation strain for damage in the fiber (longitudinal) under +compressive condition. +ILOCC +IDELC +SMATC +SFIBC +SLOCC +SDELC +ERODE +*MAT_CODAM2 +DESCRIPTION +Initiation strain for the anti-locking mechanism. This parameter +should be equal to the saturation strain for the fiber damage +mechanism under compressive condition. +Initiation strain for delamination. Not working in the current +version. Can be used for visualization purpose only. +Saturation strain for damage in matrix (transverse) under +compressive condition. +Saturation strain for damage in the fiber (longitudinal) under +compressive condition. +Saturation strain +for +compressive condition. +parameter is (ILOCC + 0.02). +the anti-locking mechanism under + The recommended value for this +Delamination strain. Not working in the current version. Can be +used for visualization purpose only. +Erosion Flag +EQ.0: Erosion is turned off. +EQ.1: Non-local strain based erosion criterion. +EQ.2: Local strain based erosion criterion. +EQ.3: Use both ERODE = 1 and ERODE = 2 criteria. +ERPAR1 +ERPAR2 +The erosion parameter #1 used in ERODE types 1 and 3. +ERPAR1>=1.0 and the recommended value is ERPAR1 = 1.2. +The erosion parameter #2 used in ERODE types 2 and 3. The +recommended value is five times SLOCC defined in cards 7 and +8. +RESIDS +Residual strength for layer damage +Model Description: +CODAM2 is developed for modeling the nonlinear, progressive damage behavior of +laminated fiber-reinforced plastic materials. The model is based on the work by +(Forghani, 2011; Forghani et al. 2011a; Forghani et al. 2011b) and is an extension of the +original model, CODAM (Williams et al. 2003). +Briefly, the model uses a continuum damage mechanics approach and the following +assumptions have been made in its development: +1. The material is an orthotropic medium consisting of a number of repeating +units through the thickness of the laminate, called sub-laminates. e.g. +[0/±45/90] in a [0/±45/90]8S laminate. +2. The nonlinear behavior of the composite sub-laminate is only caused by +damage evolution. Nonlinear elastic or plastic deformations are not consid- +ered. +Formulation: +The in-plane secant stiffness of the damaged laminate is represented as the summation +of the effective contributions of the layers in the laminate as shown. +𝐀𝑑 = ∑ 𝑡𝑘𝚻𝑘 +T𝐐𝑘 +𝑑𝚻𝑘 +𝑑 is the in-plane secant +where 𝚻𝑘 is the transformation matrix for the strain vector, and 𝐐𝑘 +stiffness of kth layer in the principal orthotropic plane, and 𝑡𝑘 is the thickness of the kth +layer of an 𝑛-layered laminate. +A physically-based and yet simple approach has been employed here to derive the +damaged stiffness matrix. Two reduction coefficients, 𝑅𝑓 and 𝑅𝑚, that represent the +reduction of stiffness in the longitudinal (fiber) and transverse (matrix) directions have +been employed. The shear modulus has also been reduced by the matrix reduction +parameter. The major and minor Poisson’s ratios have been reduced by 𝑅𝑓 and 𝑅𝑚re- +spectively. A sub-laminate-level reduction, 𝑅𝐿, is incorporated to avoid spurious stress +locking in the damaged zone. This would lead to an effective reduced stiffness matrix +𝑑. The reduction coefficients are equal to 1 in the undamaged condition and gradually +𝐐𝑘 +decrease to 0 for a saturated damage condition. +𝐐𝑘 +𝑑 = 𝑅𝐿 +𝜈12𝜈21 +𝐸1 +(𝑅𝑓 ) +(𝑅𝑚) +𝜈12𝐸2 +⎡ +⎢ +1 − (𝑅𝑓 ) +⎢ +⎢ +(𝑅𝑚) +(𝑅𝑓 ) +⎢ +⎢ +⎢ +(𝑅𝑚) +1 − (𝑅𝑓 ) +⎢ +⎢ +⎢ +⎣ +𝜈12𝜈21 +𝜈12𝐸2 +(𝑅𝑚) +(𝑅𝑚) +𝐸2 +(𝑅𝑓 ) +1 − (𝑅𝑓 ) +(𝑅𝑚) +(𝑅𝑚) +1 − (𝑅𝑓 ) +𝜈12𝜈21 +𝜈12𝜈21 +(𝑅𝑚) +𝑑T += 𝐐𝑘 +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +𝐺12⎦ +where 𝐸1, 𝐸2, 𝜈12, 𝜈21, and 𝐺12 are the elastic constants of the lamina. +*MAT_CODAM2 +In CODAM2, the evolution of damage mechanisms are expressed in terms of equivalent +strain parameters. The equivalent strain function that governs the fiber stiffness +reduction parameter is written in terms of the longitudinal normal strains by +eq = 𝜀11,𝑘, +𝜀𝑓 ,𝑘 +𝑘 = 1, . . . , 𝑛 +The equivalent strain function that governs the matrix stiffness reduction parameter is +written in an interactive form in terms of the transverse and shear components of the +local strain. +eq = sign(𝜀22,𝑘)√(𝜀22,𝑘)2 + ( +𝜀𝑚,𝑘 +𝛾12,𝑘 +) +, +𝑘 = 1, . . . , 𝑛 +The sign of the transverse normal strain plays a very important role in the initiation and +growth of damage since it indicates the compressive or tensile nature of the transverse +stress. Therefore, the equivalent strain for the matrix damage carries the sign of the +transverse normal strain. +Evolution of the overall damage mechanism (anti-locking) is written in terms of the +maximum principal strains. +eq = max[prn(ε)] +𝜀𝐿 +Within the framework of non-local strain-softening formulations adopted here, all +damage modes, be it intra-laminar (i.e. fiber and matrix damage) or overall sub- +laminate modes are considered to be a function of the non-local (averaged) equivalent +strain defined as: +eq = ∫ 𝜀𝛼 +𝜀̅𝛼 +Ω𝐗 +eq(𝐱)𝑤𝛼(𝐗 − 𝐱)𝑑Ω +where the subscript 𝛼 denotes the mode of damage: fiber (𝛼 = 𝑓 ) and matrix (𝛼 = 𝑚) +damage in each layer, 𝑘, within the sub-laminate or associated with the overall sub- +eq and +laminate, namely, locking (𝛼 = 𝐿). Thus, for a given sub-laminate with n layers,𝜀𝛼 +eq are vectors of size 2𝑛 + 1. 𝐗 represents the position vector of the original point of +𝜀̅𝛼 +interest and 𝐱 denotes the position vector of all other points (Gauss points) in the +averaging zone denoted by Ω. In classical isotropic non-local averaging approach, this +zone is taken to be spherical (or circular in 2D) with a radius of r (named R1 in the +material input card). The parameter, 𝑟, which affects the size of the averaging zone, +introduces a length scale into the model that is linked directly to the predicted size of +the damage zone. Averaging is done with a bell-shaped weight function, 𝑤𝛼, evaluated +by +𝑤𝛼 = +⎢⎡1 − ( +⎣ +) +⎥⎤ +⎦ +ε i +ε s +eq +(a) +(b) +Figure M219-1. illustrations of (a) damage parameter and (b) reduction +parameter. +where 𝑑 is the distance from the integration point of interest to another integration point +with the averaging zone. +The damage parameters, 𝜔, are calculated as a function of the corresponding averaged +equivalent strains. In CODAM2 the damage parameters are assumed to grow as a +hyperbolic function of the damage potential (non-local equivalent strains) such that +when used in conjunction with stiffness reduction factors that vary linearly with the +damage parameters they result in a linear strain-softening response (or a bilinear stress- +strain curve) for each mode of damage +eq∣ − 𝜀𝛼 +𝑖 ) +𝑖 ) +𝑠 − 𝜀𝛼 +eq∣ − 𝜀𝛼 +∣𝜀̅𝛼 +(∣𝜀̅𝛼 +(𝜀𝛼 +𝑖 > 0 +𝜔𝛼 = +, +𝜀𝛼 +𝑒𝑞∣ +∣𝜀̅𝛼 +where superscripts 𝑖 and 𝑠 denote, respectively, the damage initiation and saturation +values of the strain quantities to which they are assigned. The initiation and saturation +parameters are defined in material cards #6 and #7. Damage is considered to be a +monotonically increasing function of time, t, such that +𝜔𝛼 = max +τ 0, damage in the layers is limited such that +𝑅𝑓 = max(RESIDS, 1 − 𝜔𝑓 ) +𝑅𝑚 = max(RESIDS, 1 − 𝜔𝑚) +Element Erosion: +When ERODE > 0, an erosion criterion is checked at each integration point. Shell +elements and thick shell elements will be deleted when the erosion criterion has been +met at all integration points. Brick elements will be deleted when the erosion criterion +is met at any of the integration points. For ERODE = 1, the erosion criterion is met +when maximum principal strain exceeds either SLOCT × ERPAR1 for elements in +tension, or SLOCC × ERPAR1 for elements in compression. Elements are in tension +when the magnitude of the first principal strain is greater than the magnitude of the +third principal strain and in compression when the third principal strain is larger. +When 𝑅 > 0, the ERODE = 1 criterion is checked using the non-local (averaged) +principal strain. For ERODE = 2, the erosion criterion is met when the local (non- +averaged) maximum principal strain exceeds ERPAR2. For ERODE = 3, both of these +erosion criteria are checked. For visualization purposes, the ratio of the maximum +principal strain over the limit is stored in the location of plastic strain which is written +by default to the elout and d3plot files. +History Variables: +History variables for CODAM2 are enumerated in the following tables. To include +them in the D3PLOT database, use NEIPH (bricks) or NEIPS (shells) on *DATABASE_- +EXTENT_BINARY. For brick elements, add 4 to the variable numbers in the table +because the first 6 history variables are reserved. +*MAT_219 +VARIABLE # +DESCRIPTION +3 +4 +5 +6 +7 +8 +⋮ +Overall (anti-locking) Damage. +Delamination Damage (for visualization only) +Fiber damage in the first layer +Matrix damage in the first layer +Fiber damage in the second layer +Matrix damage in the second layer +⋮ +3 + 2 × NLAYER +Fiber damage in the last layer +4 + 2 × NLAYER +Matrix damage in the last layer +Equivalent Strains used to evaluate damage (averaged if R1 > 0) +DESCRIPTION +VARIABLE # +5 + 2 × NLAYER +6 + 2 × NLAYER +7 + 2 × NLAYER +8 + 2 × NLAYER +9 + 2 × NLAYER +⋮ +4 + 4 × NLAYER +5 + 4 × NLAYER +eq +𝜀𝑅 +eq +𝜀𝑓 ,1 +eq +𝜀𝑚,1 +eq +𝜀𝑓 ,2 +eq +𝜀𝑚,2 + ⋮ +eq +𝜀𝑓 ,𝑛 +eq +𝜀𝑓 ,𝑛 +*MAT_219 +Total Strain +VARIABLE # +6 + 4 × NLAYER +7 + 4 × NLAYER +8 + 4 × NLAYER +9 + 4 × NLAYER +10 + 4 × NLAYER +11 + 4 × NLAYER +𝜀𝑥 +𝜀𝑦 +𝜀𝑧 +𝛾𝑥𝑦 +𝛾𝑦𝑧 +𝛾𝑧𝑥 +*MAT_220 +This is Material Type 220, a rigid material for shells or solids. Unlike *MAT_020, a +*MAT_220 part can be discretized into multiple disjoint pieces and have each piece +behave as an independent rigid body. The inertia properties for the disjoint pieces are +determined directly from the finite element discretization. +Nodes of a *MAT_220 part cannot be shared by any other rigid part. A *MAT_220 part +may share nodes with deformable structural and solid elements. +This material option can be used to model granular material where the grains interact +through an automatic single surface contact definition. Another possible use includes +modeling bolts as rigid bodies where the bolts belong to the same part ID. This model +eliminates the need to represent each rigid piece with a unique part ID. +5 +6 +7 +8 +Card +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +Default +none +none +none +none + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +*MAT_ORTHOTROPIC_SIMPLIFIED_DAMAGE +This is Material Type 221. An orthotropic material with optional simplified damage +and optional failure for composites can be defined. This model is valid only for 3D +solid elements, with reduced or full integration. The elastic behavior is the same as +MAT_022. Nine damage variables are defined such that damage is different in tension +and compression. These damage variables are applicable to 𝐸𝑎, 𝐸𝑏, 𝐸𝑐, 𝐺𝑎𝑏, 𝐺𝑏𝑐 and 𝐺𝑐𝑎. +In addition, nine failure criteria on strains are available. When failure occurs, elements +are deleted (erosion). Failure depends on the number of integration points failed +through the element. See the material description below. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +EA +F +4 +EB +F +5 +EC +F +6 +7 +8 +PRBA +PRCA +PRCB +F +F +F +Default +none +none +none +none +none +none +none +none + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +GAB +GBC +GCA +AOPT +MACF +Type +F +F +F +Default +none +none +none + Card 3 +Variable +1 +XP +Type +F +2 +YP +F +3 +ZP +F +4 +A1 +F +F +0.0 +5 +A2 +F +I +0 +6 +A3 +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +7 +Card 4 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +BETA +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NERODE +NDAM +EPS1TF +EPS2TF +EPS3TF +EPS1CF +EPS2CF +EPS3CF +Type +Default +I +0 + Card 6 +1 +I +0 +2 +F +F +F +F +F +F +1020 +1020 +1020 +-1020 +-1020 +-1020 +3 +4 +5 +6 +7 +8 +Variable +EPS12F +EPS23F +EPS13F +EPSD1T +EPSC1T CDAM1T +EPSD2T +EPSC2T +Type +F +F +F +Default +1020 +1020 +1020 +F +0. +F +0. +F +0. +F +0. +F +0. + Card 7 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CDAM2T +EPSD3T +EPSC3T CDAM3T +EPSD1C +EPSC1C CDAM1C EPSD2C +Type +I +Default +0. +I +0. +F +0. +F +0. +F +0. +F +0. +F +0. +F +0. +Card 8 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EPSC2C CDAM2C EPSD3C +EPSC3C CDAM3C +EPSD12 +EPSC12 CDAM12 +Type +F +Default +0. +F +0. +F +0. +F +0. +F +0. +F +0. +F +0. +F +0. + Card 9 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EPSD23 +EPSC23 CDAM23 +EPSD31 +EPSC31 CDAM31 +Type +F +Default +0. +F +0. +F +0. +F +0. +F +0. +F +0. + VARIABLE +DESCRIPTION +MID +RO +EA +EB +EC +PRBA +PRCA +PRCB +GAB +GBC +GCA +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +𝐸𝑎, Young’s modulus in 𝑎-direction +𝐸𝑏, Young’s modulus in 𝑏-direction +𝐸𝑐, Young’s modulus in 𝑐-direction +𝜈𝑏𝑎, Poisson ratio +𝜈𝑐𝑎, Poisson ratio +𝜈𝑐𝑏, Poisson ratio +𝐺𝑎𝑏, Shear modulus +𝐺𝑏𝑐, Shear modulu +𝐺𝑐𝑎, Shear modulus +VARIABLE +AOPT +DESCRIPTION +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_ +COORDINATE_NODES. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the 𝑎-direction. This option is for solid +elements only. +EQ.2.0: globally orthotropic with material axes determined by +*DEFINE_ +as with +below, +vectors +COORDINATE_VECTOR. +defined +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector 𝐯 with the +element normal. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector 𝐯, and +an originating point, 𝐩, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_ +*DEFINE_COORDINATE_SYSTEM +COORDINATE_VECTOR). +or +MACF +Material axes change flag for brick elements: +EQ.1: No change, default, +EQ.2: switch material axes 𝐚 and 𝐛, +EQ.3: switch material axes 𝐚 and 𝐜, +EQ.4: switch material axes 𝐛 and 𝐜. +XP, YP, ZP +Coordinates of point 𝐩 for AOPT = 1 and 4 +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2 +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3 and 4 +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2 +BETA +NERODE +*MAT_ORTHOTROPIC_SIMPLIFIED_DAMAGE +DESCRIPTION +Material angle in degrees for AOPT = 3, may be overridden on +the element card, see *ELEMENT_SOLID_ORTHO. +Element erosion flag. For multi-integration point elements, each +of the failure strains mentioned below for NERODE 2 and higher +need only occur in one integration point to trigger element +erosion, and for NERODE values 6 to 11, which require more +than one failure strain be reached, those failure strains need not +occur in the same integration point. +EQ.0: No erosion (default). +EQ.1: Erosion occurs when one failure strain is reached in all +integration points. +EQ.2: Erosion occurs when one failure strain is reached. +EQ.3: Erosion occurs when a tension or compression failure +strain in the 𝑎-direction is reached. +EQ.4: Erosion occurs when as a tension or compression failure +strain in the 𝑏-direction is reached. +EQ.5: Erosion occurs when a tension or compression failure +strain in the 𝑐-direction is reached. +EQ.6: Erosion occurs when tension or compression failure +strain in both the 𝑎- and 𝑏-directions are reached. +EQ.7: Erosion occurs when tension or compression failure +strain in both the 𝑏- and 𝑐-directions are reached. +EQ.8: Erosion occurs when tension or compression failure +strain in both the 𝑎- and 𝑐-directions are reached. +EQ.9: Erosion occurs when tension or compression failure +strain in all 3 directions are reached. +EQ.10:Erosion occurs when tension or compression failure +strain in both the 𝑎- and 𝑏-directions are reached and +either of the out-of-plane failure shear strains (bc or ac) is +reached. . +EQ.11:Erosion occurs when tension failure strain in either the 𝑎- +or 𝑏-directions is reached and either of the out-of-plane +failure shear strains (bc or ac) is reached. +VARIABLE +DESCRIPTION +NDAM +Damage flag: +EQ.0: No damage (default) +EQ.1: Damage in tension only (null for compression) +EQ.2: Damage in tension and compression +EPS1TF +Failure strain in tension along the 𝑎-direction +EPS2TF +Failure strain in tension along the 𝑏-direction +EPS3TF +Failure strain in tension along the 𝑐-direction +EPS1CF +Failure strain in compression along the 𝑎-direction +EPS2CF +Failure strain in compression along the 𝑏-direction +EPS3CF +Failure strain in compression along the 𝑐-direction +EPS12F +Failure shear strain in the 𝑎𝑏-plane +EPS23F +Failure shear strain in the 𝑏𝑐-plane +EPS13F +Failure shear strain in the 𝑎𝑐-plane +EPSD1T +EPSC1T +𝑠 +Damage threshold in tension along the 𝑎-direction, 𝜀1𝑡 +𝑐 +Critical damage threshold in tension along the 𝑎-direction, 𝜀1𝑡 +CDAM1T +𝑐 +Critical damage in tension along the 𝑎-direction, 𝐷1𝑡 +EPSD2T +EPSC2T +𝑠 +Damage threshold in tension along the 𝑏-direction, 𝜀2𝑡 +𝑐 +Critical damage threshold in tension along the b-direction, 𝜀2𝑡 +CDAM2T +𝑐 +Critical damage in tension along the 𝑏-direction, 𝐷2𝑡 +EPSD3T +EPSC3T +𝑠 +Damage threshold in tension along the 𝑐-direction, 𝜀3𝑡 +𝑐 +Critical damage threshold in tension along the 𝑐-direction, 𝜀3𝑡 +CDAM3T +𝑐 +Critical damage in tension along the 𝑐-direction, 𝐷3𝑡 +EPSD1C +EPSC1C +𝑠 +Damage threshold in compression along the 𝑎-direction, 𝜀1𝑐 +Critical damage threshold in compression along the 𝑎-direction, +𝑐 +𝜀1𝑐 +*MAT_ORTHOTROPIC_SIMPLIFIED_DAMAGE +DESCRIPTION +CDAM1C +𝑐 +Critical damage in compression along the 𝑎-direction, 𝐷1𝑐 +EPSD2C +EPSC2C +𝑠 +Damage threshold in compression along the 𝑏-direction, 𝜀2𝑐 +Critical damage +𝑐 +direction, 𝜀2𝑐 +threshold +in compression along +the 𝑏- +CDAM2C +𝑐 +Critical damage in compression along the 𝑏-direction, 𝐷2𝑐 +EPSD3C +EPSC3C +𝑠 +Damage threshold in compression along the 𝑐-direction, 𝜀3𝑐 +Critical damage threshold in compression along the 𝑐-direction, +𝑐 +𝜀3𝑐 +CDAM3C +𝑐 +Critical damage in compression along the 𝑐-direction, 𝐷3𝑐 +EPSD12 +EPSC12 +𝑠 +Damage threshold for shear in the 𝑎𝑏-plane, 𝜀12 +𝑐 +Critical damage threshold for shear in the 𝑎𝑏-plane, 𝜀12 +CDAM12 +𝑐 +Critical damage for shear in the 𝑎𝑏-plane, 𝐷12 +EPSD23 +EPSC23 +𝑠 +Damage threshold for shear in the 𝑏𝑐-plane, 𝜀23 +𝑐 +Critical damage threshold for shear in the 𝑏𝑐-plane, 𝜀23 +CDAM23 +𝑐 +Critical damage for shear in the 𝑏𝑐-plane, 𝐷23 +EPSD31 +EPSC31 +𝑠 +Damage threshold for shear in the 𝑎𝑐-plane, 𝜀31 +𝑐 +Critical damage threshold for shear in the 𝑎𝑐-plane, 𝜀31 +CDAM31 +𝑐 +Critical damage for shear in the 𝑎𝑐-plane, 𝐷31 +Remarks: +If 𝜀𝑘 +𝑐 < 𝜀𝑘 +𝑠 , no damage is considered. Failure occurs only when failure strain is reached. +Failure can occur along the 3 orthotropic directions, in tension, in compression and for +shear behavior. Nine failure strains drive the failure. When failure occurs, elements are +deleted (erosion). Under the control of the NERODE flag, failure may occur either +when only one integration point has failed, when several integration points have failed +or when all integrations points have failed. +Damage applies to the 3 Young’s moduli and the 3 shear moduli. Damage is different +for tension and compression. Nine damage variables are used: 𝑑1𝑡, 𝑑2𝑡, 𝑑3𝑡, 𝑑1𝑐, 𝑑2𝑐, 𝑑3𝑐, +𝑑12, 𝑑23, 𝑑13. The damaged flexibility matrix is: +𝐸𝑎(1 − 𝑑1[𝑡,𝑐]) +−𝜐𝑏𝑎 +𝐸𝑏 +−𝜐𝑐𝑎 +𝐸𝑐 +−𝜐𝑏𝑎 +𝐸𝑏 +𝐸𝑏(1 − 𝑑2[𝑡,𝑐]) +−𝜐𝑐𝑏 +𝐸𝑐 +−𝜐𝑐𝑎 +𝐸𝑐 +−𝜐𝑐𝑏 +𝐸𝑐 +𝐸𝑐(1 − 𝑑3[𝑡,𝑐]) +𝐺𝑎𝑏(1 − 𝑑12) +𝐺𝑏𝑐(1 − 𝑑23) + 𝑆dam = +⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎛ +⎝ +The nine damage variables are calculated as follows: +𝑑𝑘 = max (𝑑𝑘; 𝐷𝑘 +𝑐 ⟨ +𝜀𝑘 − 𝜀𝑘 +𝑠 ⟩ +𝑐 − 𝜀𝑘 +𝜀𝑘 ++ +) +⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎞ +𝐺𝑐𝑎(1 − 𝑑31)⎠ +with k = 1t, 2t, 3t, 1c, 2c, 3c, 12, 23, 31. +⟨ +⟩+ is the positive part: ⟨𝑥⟩+ = { +if x > 0 +if x < 0 +. +Damage in compression may be deactivated with the NDAM flag. In this case, damage +in compression is null, and only damage in tension and for shear behavior are taken +into account. +The nine damage variables may be post-processed through additional variables. The +number of additional variables for solids written to the d3plot and d3thdt databases is +input by the optional *DATABASE_EXTENT_BINARY card as variable NEIPH. These +additional variables are tabulated below: +History +Variable +Description +Value +𝑑1𝑡 +𝑑2𝑡 +𝑑3𝑡 +𝑑1𝑐 +𝑑2𝑐 +𝑑3𝑐 +𝑑12 +damage in traction along 𝑎 +damage in traction along 𝑏 +damage in traction along 𝑐 +damage in compression along 𝑎 +0 - no damage +damage in compression along 𝑏 +damage in compression along 𝑐 +0 < 𝑑𝑘 < 𝐷𝑘 +𝑐 - damage +shear damage in 𝑎𝑏-plane +LS-PrePost +History Variable +plastic strain +1 +2 +3 +4 +5 +History +Variable +Description +Value +𝑑23 +𝑑13 +shear damage in 𝑏𝑐-plane +shear damage in 𝑎𝑐-plane +LS-PrePost +History Variable +7 +8 +The first damage variable is stored as in the place of effective plastic strain. The eight +other damage variables may be plotted in LS-PrePost as element history variables. +*MAT_TABULATED_JOHNSON_COOK +This is Material Type 224. An elasto-viscoplastic material with arbitrary stress versus +strain curve(s) and arbitrary strain rate dependency can be defined. Plastic heating +causes adiabatic temperature increase and material softening. Optional plastic failure +strain can be defined as a function of triaxiality, strain rate, temperature and/or element +size. Please take careful note the sign convention of triaxiality used for *MAT_224 as +illustrated in Figure M224-1. +This material model resembles the original Johnson-Cook material but +with the possibility of general tabulated input parameters. +An equation of state (*EOS) is optional for solid elements, tshell formulations 3 and 5, +and 2D continuum elements, and is invoked by setting EOSID to a nonzero value in +*PART. If an equation of state is used, only the deviatoric stresses are calculated by the +material model and the pressure is calculated by the equation of state. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +CP +F +6 +TR +F +7 +8 +BETA +NUMINT +F +F +Default +none +none +none +none +none +0.0 +1.0 +1.0 + Card 2 +1 +2 +3 +4 +5 +Variable +LCK1 +LCKT +LCF +LCG +LCH +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +6 +LCI +F +0 +7 +*MAT_TABULATED_JOHNSON_COOK + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FAILOPT NUMAVG NCYFAIL +ERODE +LCPS +Type +F +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +CP +TR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus: +GT.0.0: constant value is used +LT.0.0: -E gives curve ID for temperature dependence +Poisson’s ratio. +Specific heat (superseded by heat capacity in *MAT_THERMAL_ +OPTION if a coupled thermal/structural analysis). +Room temperature. +BETA +Fraction of plastic work converted into heat: +GT.0.0: constant value is used +LT.0.0: -BETA gives either a curve ID for strain rate +dependence or a table ID for strain rate and tempera- +ture dependence. +VARIABLE +NUMINT +DESCRIPTION +GT.0.0: Number of integration points which must fail before +the element is deleted. Available for shells and sol- +ids. +LT.0.0: +-NUMINT is percentage of integration points/layers +which must fail before shell element fails. For fully +integrated shells, a methodology is used where a lay- +er fails if one integration point fails and then the giv- +en percentage of layers must fail before the element +fails. Only available for shells except as noted below +EQ.-200: Turns off erosion for shells and solids. +recommended unless used +*CONSTRAINED_TIED_NODES_FAILURE. + Not +in conjunction with +LCK1 +LCKT +LCF +LCG +LCH +Load curve ID or Table ID. The load curve ID defines effective +stress as a function of effective plastic strain. The table ID defines +for each plastic strain rate value a load curve ID giving the +(isothermal) effective stress versus effective plastic strain for that +rate. As in *MAT_024, natural logarithmic strain rates can be +used by setting the first strain rate to a negative value. +Table ID defining for each temperature value a load curve ID +giving the (quasi-static) effective stress versus effective plastic +strain for that temperature. +Load curve ID or Table ID. The load curve ID defines plastic +failure strain (or scale factor – see Remarks) as a function of +triaxiality. The table ID defines for each Lode parameter a load +curve ID giving the plastic failure strain versus triaxiality for that +Lode parameter. (Table option only for solids and not yet +generally supported). See Remarks for a description of the +combination of LCF, LCG, LCH, and LCI. +Load curve ID defining plastic failure strain (or scale factor – see +Remarks) as a function of plastic strain rate. If the first abscissa +value in the curve corresponds to a negative strain rate, LS- +DYNA assumes that the natural logarithm of the strain rate value +is used for all abscissa values. See Remarks for a description of +the combination of LCF, LCG, LCH, and LCI. +Load curve ID defining plastic failure strain (or scale factor – see +Remarks) as a function of temperature. See Remarks for a +description of the combination of LCF, LCG, LCH, and LCI. +LCI +*MAT_TABULATED_JOHNSON_COOK +DESCRIPTION +Load curve ID, Table ID, or Table_3D ID. The load curve ID +defines plastic failure strain (or scale factor – see Remarks) as a +function of element size. The table ID defines for each triaxiality a +load curve ID giving the plastic failure strain versus element size +for that triaxiality. If a three dimensional table ID is referred, +plastic failure strain can be a function of Lode parameter +(TABLE_3D), triaxiality (TABLE), and element size (CURVE). See +Remarks for a description of the combination of LCF, LCG, LCH, +and LCI. +FAILOPT +Flag for additional failure criterion 𝐹2, see Remarks. +EQ.0.0: off (default) +EQ.1.0: on +NUMAVG +NCYFAIL +Number of time steps for running average of plastic failure strain +in the additional failure criterion. Default is 1 (no averaging). +Number of time steps that the additional failure criterion must be +met before element deletion. Default is 1. +ERODE +Erosion flag (only for solid elements): +EQ.0.0: default, element erosion is allowed. +EQ.1.0: element does not erode; deviatoric stresses set to zero +when element fails. +Table ID with first principal stress limit as function of plastic +strain (curves) and plastic strain rate (table). This option is for +post-processing purposes only and gives an indication of areas in +the structure where failure is likely to occur. History variable #17 +shows a value of 1.0 for integration points that exceeded the limit, +else a value of 0.0. +LCPS +Remarks: +The flow stress 𝜎𝑦 is expressed as a function of plastic strain 𝜀𝑝, plastic strain rate 𝜀̇𝑝 and +temperature 𝑇 via the following formula (using load curves/tables LCK1 and LCKT): +𝑠𝑦 = 𝑘1(𝜀𝑝, 𝜀̇𝑝) +𝑘𝑡(𝜀𝑝, 𝑇) +𝑘𝑡(𝜀𝑝, 𝑇𝑅) +Note that 𝑇𝑅 is a material parameter and should correspond to the temperature used +when performing the room temperature tensile tests. If simulations are to be performed +plastic +failure +strain +tension +compression +-2/3 +-1/3 +triaxiality +p/σ +vm +1/3 +2/3 +Figure M224-1. Typical failure curve for metal sheet, modeled with shell +elements. +with an initial temperature TI deviating from 𝑇𝑅 then this temperature should be set +using *INITIAL_STRESS_SOLID/SHELL by setting history variable #14 for solid +elements or history variable #10 for shell elements. +Optional plastic failure strain is defined as a function of triaxiality +parameter, plastic strain rate +element area for shells and volume over maximum area for solids) by +𝑝/𝜎𝑣𝑚, Lode +𝜀̇𝑝, temperature 𝑇 and initial element size 𝑙c (square root of +𝜀𝑝𝑓 = 𝑓 ( +𝜎vm +, +27𝐽3 +2𝜎vm +3 ) 𝑔(𝜀̇𝑝)ℎ(𝑇)𝑖 (𝑙𝑐, +𝜎vm +) +using load curves/tables LCF, LCG, LCH and LCI. If more than one of these four +variables LCF, LCG, LCH and LCI are defined, be aware that the net plastic failure +strain is essentially the product of multiple functions as shown in the above equation. +This means that one and only one of the variables LCF, LCG, LCH, and LCI can point to +curve(s) that have plastic strain along the curve ordinate. The remaining nonzero +variable(s) LCF, LCG, LCH, and LCI should point to curve(s) that have a unitless +scaling factor along the curve ordinate. +A typical failure curve LCF for metal sheet, modeled with shell elements is shown in +Figure M224-1. Triaxiality should be monotonically increasing in this curve. A +reasonable range for triaxiality is -2/3 to 2/3 if shell elements are used (plane stress). +For 3-dimensional stress states (solid elements), the possible range of triaxiality goes +from -∞ to +∞, but to get a good resolution in the internal load curve discretization +(depending on parameter LCINT of *CONTROL_SOLUTION) one should define lower +limits, e.g. -1 to 1 if LCINT = 100 (default). +The default failure criterion of this material model depends on plastic strain evolution +𝜀̇𝑝 and on plastic failure strain 𝜀𝑝𝑓 and is obtained by accumulation over time: +𝐹 = ∫ +𝜀̇𝑝 +𝜀𝑝𝑓 +𝑑𝑡 +where element erosion takes place when 𝐹 ≥ 1. This accumulation provides load-path +dependent treatment of failure. The value of 𝐹 is stored as history variable #8 for shells +and #12 for solids. +An additional, load-path independent, failure criterion can be invoked by setting +FAILOPT = 1, where the current state of plastic strain is used: +𝐹2 = +𝜀𝑝 +𝜀𝑝𝑓 +Two additional parameters can be used as countermeasures against stress oscillations +for this failure criterion. With NUMAVG active, plastic failure strain is averaged over +NUMAVG time steps for the 𝐹2 criterion. The value of 𝐹2, taking into account any +averaging per NUMAVG, is stored as history variable #14 for shells and #16 for solids. +NUMAVG cannot exceed 30. NCYFAIL defines the number of time steps that 𝐹2 ≥ 1 +must be met before element deletion takes place. The number of time steps that 𝐹2 ≥ 1 +is stored as history variable #15 for shells and #19 for solids. +Temperature increase is caused by plastic work +𝑇 = 𝑇𝑅 + +𝐶𝑝𝜌 +∫ 𝜎𝑦𝜀̇𝑝𝑑𝑡 +with room temperature 𝑇𝑅, dissipation factor 𝛽, specific heat 𝐶𝑝, and density 𝜌. +For *CONSTRAINED_TIED_NODES_WITH_FAILURE, the failure is based on the +damage instead to the plastic strain. +History variables may be post-processed through additional variables. The number of +additional variables for shells/solids written to the d3plot and d3thdt databases is input +by the optional *DATABASE_EXTENT_BINARY card as variable NEIPS/NEIPH. The +relevant additional variables of this material model are tabulated below: +LS-PrePost +history +variable # +1 +7 +8 +9 +10 +11 +12 +17 +Shell elements +plastic strain rate +plastic work +ratio of plastic strain to +plastic failure strain +element size +temperature +plastic failure strain +triaxiality +LCPS: critical value +LS-PrePost +history +variable # +5 +8 +9 +10 +11 +12 +13 +14 +17 +Solid elements +plastic strain rate +plastic failure strain +triaxiality +Lode parameter +plastic work +ratio of plastic strain to +plastic failure strain +element size +temperature +LCPS: critical value +*MAT_TABULATED_JOHNSON_COOK_GYS +This is Material Type 224_GYS. This is an isotropic elastic plastic material law with J3 +dependent yield surface. This material considers tensile/compressive asymmetry in the +material response, which is important for HCP metals like Titanium. The model is +available for solid elements. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +CP +F +6 +TR +F +7 +8 +BETA +NUMINT +F +F +Default +none +none +none +none +none +0.0 +1.0 +1.0 + Card 2 +1 +2 +3 +4 +5 +Variable +LCK1 +LCKT +LCF +LCG +LCH +Type +Default +F +0 + Card 3 +1 +F +0 +2 +F +0 +3 +F +0 +4 +F +0 +5 +6 +LCI +F +0 +6 +7 +8 +7 +8 +Variable +LCCR +LCCT +LCSR +LCST +IFLAG +SFIEPM +NITER +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +1 +100 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +VARIABLE +DESCRIPTION +E +Young’s modulus: +GT.0.0: constant value is used +LT.0.0: temperature dependent Young’s modulus given by +load curve ID = -E +PR +CP +TR +Poisson’s ratio. +Specific heat. +Room temperature. +BETA +Fraction of plastic work converted into heat. +NUMINT +Number of integration points which must fail before the element +is deleted. +LCK1 +LCKT +LCF +LCG +LCH +LCI +EQ.-200: Turns off erosion for solids. Not recommended +unless used in conjunction with *CONSTRAINED_- +TIED_NODES_FAILURE. +Table ID defining for each plastic strain rate value a load curve ID +giving the (isothermal) effective stress versus effective plastic +strain for that rate. +Table ID defining for each temperature value a load curve ID +giving the (quasi-static) effective stress versus effective plastic +strain for that temperature. +Load curve ID or Table ID. The load curve ID defines plastic +failure strain as a function of triaxiality. The table ID defines for +each Lode parameter a load curve ID giving the plastic failure +strain versus triaxiality for that Lode parameter. (Table option +only for solids and not yet generally supported). +Load curve ID defining plastic failure strain as a function of +plastic strain rate. +Load curve ID defining plastic failure strain as a function of +temperature +Load curve ID or Table ID. The load curve ID defines plastic +failure strain as a function of element size. The table ID defines +for each triaxiality a load curve ID giving the plastic failure strain +versus element size for that triaxiality. +VARIABLE +LCCR +LCCT +LCSR +LCST +DESCRIPTION +Table ID. The curves in this table define compressive yield stress +as a function of plastic strain or effective plastic strain . The table ID defines for each plastic strain rate value or +effective plastic strain rate value a load curve ID giving the +(isothermal) compressive yield stress versus plastic strain or +effective plastic strain for that rate. +Table ID defining for each temperature value a load curve ID +giving the (quasi-static) compressive yield stress versus strain for +that temperature. The curves in this table define compressive +yield stress as a function of plastic strain or effective plastic strain +. +Table ID. The load curves define shear yield stress in function of +plastic strain or effective plastic strain .The table ID +defines for each plastic strain rate value or effective plastic strain +rate value a load curve ID giving the (isothermal) shear yield +stress versus plastic strain or effective plastic strain for that rate. +Table ID defining for each temperature value a load curve ID +giving the (quasi-static) shear yield stress versus strain for that +temperature. The load curves define shear yield stress as a +function of plastic strain or effective plastic strain . +IFLAG +Flag to specify abscissa for LCCR, LCCT, LCSR, LCST: +EQ.0.0: Compressive and shear yields are given in a function of +plastic strain as defined in the remarks (default). +EQ.1.0: Compressive and shear yields are given in function of +effective plastic strain. +SFIEPM +Scale factor on the initial estimate of the plastic multiplier. +NITER +Number of secant iterations to be performed. +Remarks: +If IFLAG = 0 the compressive and shear curves are defined as follows: +σ𝑐(𝜀𝑝𝑐, 𝜀̇𝑝𝑐), 𝜀𝑝𝑐 = 𝜀𝑐 − +σ𝑠(𝛾𝑝𝑠, 𝛾̇𝑝𝑠), 𝛾𝑝𝑠 = 𝛾𝑠 − +𝜎𝑐 +𝜎𝑠 +, 𝜀̇𝑝𝑐 = +, 𝛾̇𝑝𝑠 = +𝜕𝜀𝑝𝑐 +𝜕𝑡 +𝜕𝛾𝑝𝑠 +𝜕𝑡 +and two new history variables (#16 plastic strain in compression and #17 plastic strain +in shear) are stored in addition to those history variables already stored in MAT_224. +If IFLAG = 1 the compressive and shear curves are defined as follows: +σ𝑐(𝜆̇, 𝜆), 𝜎𝑠(𝜆̇, 𝜆), 𝑊𝑝̇ = 𝜎eff𝜆̇ +History variables may be post-processed through additional variables. The number of +additional variables for solids written to the d3plot and d3thdt databases is input by the +optional *DATABASE_EXTENT_BINARY card as variable NEIPH. The relevant +additional variables of this material model are tabulated below: +LS-PrePost history +variable # +5 +8 +9 +10 +11 +12 +13 +14 +16 +17 +Solid elements +plastic strain rate +plastic failure strain +triaxiality +Lode parameter +plastic work +damage +element size +temperature +plastic strain in compression +plastic strain in shear +*MAT_VISCOPLASTIC_MIXED_HARDENING +This is Material Type 225. An elasto-viscoplastic material with an arbitrary stress versus +strain curve and arbitrary strain rate dependency can be defined. Kinematic, isotropic, or a +combination of kinematic and isotropic hardening can be specified. Also, failure based on +plastic strain can be defined. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +6 +7 +8 +LCSS +BETA +I +F +Default +none +none +none +none +none +0.0 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FAIL +Type +F +Default 1.0E+20 + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +VARIABLE +LCSS +DESCRIPTION +Load curve ID or Table ID. Load curve ID defining effective +stress versus effective plastic strain The table ID defines for each +strain rate value a load curve ID giving the stress versus effective +plastic strain for that rate, See Figure M24-1. The stress versus +effective plastic strain curve for the lowest value of strain rate is +used if the strain rate falls below the minimum value. Likewise, +the stress versus effective plastic strain curve for the highest value +of strain rate is used if the strain rate exceeds the maximum value. +NOTE: The strain rate values defined in the table may be given as +the natural logarithm of the strain rate. If the first stress-strain +curve in the table corresponds to a negative strain rate, LS-DYNA +assumes that the natural logarithm of the strain rate value is used. +Since the tables are internally discretized to equally space the +points, natural logarithms are necessary, for example, if the +curves correspond to rates from 10.e-04 to 10.e+04. +BETA +Hardening parameter, 0 < BETA < 1. +EQ.0.0: +EQ.1.0: +Pure kinematic hardening +Pure isotropic hardening +0.0 < BETA < 1.0: Mixed hardening +FAIL +Failure flag. +LT.0.0: User defined failure subroutine is called to determine +failure +EQ.0.0: Failure is not considered. This option is recommended +if failure is not of interest since many calculations will +be saved. +GT.0.0: Plastic strain to failure. When the plastic strain +reachesthis value, the element is deleted from the cal- +culation.. +*MAT_KINEMATIC_HARDENING_BARLAT89_{OPTION} +This is Material Type 226. This model combines Yoshida non-linear kinematic +hardening rule (*MAT_125) with the 3-parameter material model of Barlat and Lian +[1989] (*MAT_36) to model metal sheets under cyclic plasticity loading and with +anisotropy in plane stress condition. Lankford parameters are used for the definition of +the anisotropy. Yoshida’s theory describes the hardening rule with ‘two surfaces’ +method: the yield surface and the bounding surface. In the forming process, the yield +surface does not change in size, but its center moves with deformation; the bounding +surface changes both in size and location. +Available options include: + +NLP +The NLP option estimates failure using the Formability Index (F.I.), which accounts for +the non-linear strain paths seen in metal forming applications . When the +NLP option is invoked, the variable IFLD must be specified. Additionally, the option +NLP is also available in *MAT_036, *MAT_037 and *MAT_125. + Card 1 +1 +Variable +MID +Type +I +2 +RO +F +3 +E +F +4 +PR +F +5 +M +F +6 +7 +8 +R00 +R45 +R90 +F +F +F +Default +none +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +none + Card 2 +Variable +1 +CB +Type +F +2 +Y +F +3 +SC +F +4 +K +F +5 +RSAT +F +6 +SB +F +7 +H +F +8 +HLCID +I +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +none +Card 3 +1 +2 +Variable +AOPT +IOPT +Type +F +I +3 +C1 +F +4 +C2 +F +5 +6 +7 +8 +IFLD +I +Default +none +none +0.0 +0.0 +none + Card 4 +Variable +1 +XP +Type +F +2 +YP +F +3 +ZP +F +4 +A1 +F +5 +A2 +F +6 +A3 +F +7 +8 +Default +none +none +none +none +none +none + Card 5 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +BETA +F +Default +none +none +none +none +none +none +none + VARIABLE +DESCRIPTION +MID +Material identification. A unique number must be specified. +RO +E +PR +M +R00 +R45 +Mass density. +Young’s modulus, E. +Poisson’s ratio, ν. +m, the exponent in Barlat’s yield criterion. +𝑅00, Lankford parameter in 0 degree direction. +𝑅45, Lankford parameter in 45 degree direction. +R90 +CB +Y +SC +K +*MAT_KINEMATIC_HARDENING_BARLAT89 +DESCRIPTION +𝑅90, Lankford parameter in 90 degree direction. +The uppercase 𝐵 defined in the Yoshida’s equations. +Hardening parameter as defined in the Yoshida’s equations. +The lowercase 𝑐 defined in the Yoshida’s equations. +Hardening parameter as defined in the Yoshida’s equations. +RSAT +Hardening parameter as defined in the Yoshida’s equations. +SB +H +HLCID +The lowercase 𝑏 as defined in the Yoshida’s equations. +Anisotropic parameter +stagnation, defined in the Yoshida’s equations. +associated with work-hardening +Load curve ID in keyword *DEFINE_CURVE, where true strain +and true stress relationship is characterized. The load curve is +optional, and is used for error calculation only. +IOPT +Kinematic hardening rule flag: +EQ.0: Original Yoshida formulation, +EQ.1: Modified formulation: define C1, C2 as below. +C1, C2 +Constants used to modify 𝑅: +𝑅 = RSAT × [(𝐶1 + 𝜀̅𝑝)𝑐2 − 𝐶1 +𝑐2] +IFLD +ID of a load curve of the traditional Forming Limit Diagram +(FLD) for the linear strain paths. In the load curve, abscissas +represent minor strains while ordinates represent major strains. +Define only when the NLP option is used. See the example in the +remarks section. +AOPT +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the shell ele- +ment normal by theangle BETA. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +VARIABLE +DESCRIPTION +NATE_VECTOR: +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal: +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE__CO- +ORDINATE_VECTOR):Available with the R3 release +of Version 971 and later. +XP, YP, ZP +Coordinates of point 𝐩 for AOPT = 1. +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3. +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2. +BETA +Material angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA. +On Barlat and Lian’s yield criteron: +The 𝑅-values are defined as the ratio of instantaneous width change to instantaneous +thickness change. That is, assume that the width 𝑊 and thickness 𝑇 are measured as +function of strain. Then the corresponding 𝑅-value is given by: +𝑅 = +𝑑𝑊 +𝑑𝜀 +𝑑𝑇 +𝑑𝜀 +/𝑊 +/𝑇 +Input R00, R45 and R90 to define sheet anisotropy in the rolling, 45 degree and 90 +degree direction. +Barlat and Lian’s [1989] anisotropic yield criterion Φ for plane stress is defined as: +𝑚 +Φ = 𝑎|𝐾1 + 𝐾2|𝑚 + 𝑎|𝐾1 − 𝐾2|𝑚 + 𝑐|2𝐾2|𝑚 = 2𝜎𝑌 +for face centered cubic (FCC) materials exponent m = 8 is recommended and for body +centered cubic (BCC) materials m = 6 may be used. Detailed description on the criterion +can be found in *MAT_036 manual pages. +On Yoshida nonlinear kinematic hardening model: +Background. +The Yoshida’s model accounts for cyclic plasticity including Bauschinger effect and +cyclic hardening behavior. For detailed Yoshida’s theory of nonlinear kinematic +hardening rule and definitions of material constants CB, Y, SC, K, RSAT, SB, and H, +refer to Remarks in *MAT_125 manual pages and in the original paper, “A model of +large-strain cyclic plasticity describing the Baushinger effect and workhardening stagnation”, +by Yoshida, F. and Uemori, T., Int. J. Plasticity, vol. 18, 661-689, 2002. +Further improvements in the original Yoshida’s model, as described in a paper +“Determination of Nonlinear Isotropic/Kinematic Hardening Constitutive Parameter for AHSS +using Tension and Compression Tests”, by Shi, M.F., Zhu, X.H., Xia, C., and Stoughton, T., +in NUMISHEET 2008 proceedings, 137-142, 2008, included modifications to allow work +hardening in large strain deformation region, avoiding the problem of earlier +saturation, especially for Advanced High Strength Steel (AHSS). These types of steels +exhibit continuous strain hardening behavior and a non-saturated isotropic hardening +function. As described in the paper, the evolution equation for R (a part of the current +radius of the bounding surface in deviatoric stress space), as is with the saturation type +of isotropic hardening rule proposed in the original Yoshida model, +is modified as, +𝑅̇ = 𝑚(𝑅sat − 𝑅)𝑝̇ +𝑅 = RSAT × [(𝐶1 + 𝜀̅𝑝)𝑐2 − 𝐶1 +𝑐2] +For saturation type of isotropic hardening rule, set IOPT = 0, applicable to most of +Aluminum sheet materials. In addition, the paper provides detailed variables used for +this material model for DDQ, HSLA, DP600, DP780 and DP980 materials. Since the +symbols used in the paper are different from what are used here, the following table +provides a reference between symbols used in the paper and variables here in this +keyword: +B +CB +Y +Y +C +SC +m +K +K +Rsat +b +SB +h +H +e0 +C1 +N +C2 +b: R90 +For shells, define vector +a, so, +c = n +b = c × a +a = b × c +a: rolling direction R00 +v × n +For shells, define vector +v, so, +c = n +a = v × n +b = n × a +AOPT = 2 +AOPT = 3 +Figure M226-1. Defining sheet metal rolling direction. +Using the modified formulation and the material properties provided by the paper, the +predicted and tested results compare very well both in a full cycle tension and +compression test and in a pre-strained tension and compression test, according to the +paper. A set of experiments are required to fit (optimize) the Yoshida material +constants, and these experiments include a uniaxial tension test (used for HLCID) to a +sufficiently large strain range, a full cycle tension and compression test and a multiple +cycle tension and compression test. +Defining the rolling direction of a sheet metal. +The variable AOPT is used to define the rolling direction of the sheet metals. For shells, +AOPT of 2 or 3 are relevant. When AOPT = 2, define vector components of a in the +direction of the rolling (R00); when AOPT = 3, define vector components of v +perpendicular to the rolling direction, as shown in Figure M226-1. +Application. +Application of the modified Yoshida’s hardening rule in the metal forming industry has +shown significant improvement in springback prediction accuracy, which is a pre- +requisite for a successful stamping tool compensation, especially for AHSS type of sheet +materials. +Figure M226-2. The NUMISHEET 2005 cross member and section definition. +In an example shown in Figure M226-2, springback simulation was performed +following drawing and trimming on the NUMISHEET 2005 cross member for +aluminum alloy AL5182-O, using *MAT_226. In Figure M226-3, springback shape was +recovered from section A-A (Figure M226-2), and compared with those results from +simulation using *MAT_037 and *MAT_125. Though all are remarkably close, results +with *MAT_226 on the cross section (Y = -370 mm) show better springback correlation +to the measured test data than those with *MAT_125 and *MAT_37. +To improve convergence, it is recommended that *CONTROL_IMPLICIT_FORMING +type ‘1’ be used when conducting springback simulation. +A Failure Criterion for Nonlinear Strain Paths (NLP): +The NLP failure criterion and corresponding post processing procedures are described +in the entries for *MAT_036 and *MAT_037. The history variables for every element +stored in d3plot files include: +1. Formability Index (F.I.): #1 +2. Strain ratio (in-plane minor strain/major strain): #2 +3. Effective strain from the planar isotropic assumption: #3 +The entire time history can be plotted using Post/History menu in LS-PrePost v4.0. To +enable the output of these history variables to the d3plot files, NEIPS on the *DATA- +BASE_EXTENT_BINARY card must be set to at least 3. When plotting the formability +index, first select the history var #1 from the Misc in the FriComp menu. The pull-down +menu under FriComp can be used to select minimum value ‘Min’ for necking failure +determination (refer to Tharrett and Stoughton’s paper in 2003 SAE 2003-01-1157). In +FriRang, the option None is to be selected in the pull-down menu next to Avg. Lastly, set +the simulation result to the last state in the animation tool bar. The index value ranges +from 0.0 to 1.5. The non-linear forming limit is reached when the index reaches 1.0. +A partial keyword example is listed below when the option NLP is used. In this +example, the traditional Forming Limit Diagram (FLD) which handles only the linear +strain paths is defined by load curve ID 213. +*MAT_KINEMATIC_HARDENING_BARLAT89_NLP +$# mid ro e pr m r00 r45 r90 + 1 2.8900E-9 7.0E+4 0.333 8.0 0.699 0.776 0.775 +$# cb y sc k rsat sb h hlcid + 122.3 110.2 577.5 12.0 201.7 16.5 0.16 0 +$# aopt iopt c1 c2 IFLD + 2 0 213 +$# xp yp zp a1 a2 a3 + 0.000 0.000 0.000 1.000000 0.000 0.000 +$# v1 v2 v3 d1 d2 d3 beta + 0.000 0.000 0.000 0.000 0.000 0.000 0.000 +*DEFINE_CURVE +213 +-0.300,0.36 +-0.200,0.32 +-0.114,0.266 +-0.058,0.223 +0.026,0.181 +0.036,0.181 +0.111,0.211 +0.147,0.23 +0.215,0.27 +0.263,0.278 +Revision information: +This material model is available starting in Revision 57717. The NLP option is available +starting in Revision 95599. +AL5182 springback comparison among +test data/M226/M125/M37 at section A-A (Y=-370mm) +-100 +-50 +20 +50 +100 +150 +200 +Experiments +M226 m=8 +M125 +M37 +1.3 mm +100 +120 +140 +160 +Figure M226-3. Springback prediction with *MAT_226 (Material properties +courtesy of Ford Motor Company Research and Innovation Laboratory). +*MAT_230 +This is Material Type 230. This is a perfectly-matched layer (PML) material — an +absorbing layer material used to simulate wave propagation in an unbounded isotropic +elastic medium — and is available only for solid 8-node bricks (element type 2). This +material implements the 3D version of the Basu-Chopra PML [Basu and Chopra +(2003,2004), Basu (2009)]. +5 +6 +7 +8 +Card +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +Default +none +none +none +none + VARIABLE +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +MID +RO +E +PR +Remarks: +1. A layer of this material may be placed at a boundary of a bounded domain to +simulate unboundedness of the domain at that boundary: the layer absorbs and +attenuates waves propagating outward from the domain, without any signifi- +cant reflection of the waves back into the bounded domain. The layer cannot +support any static displacement. +2. +It is assumed the material in the bounded domain near the layer is, or behaves +like, an isotropic linear elastic material. The material properties of the layer +should be set to the corresponding properties of this material. +3. The layer should form a cuboid box around the bounded domain, with the axes +of the box aligned with the coordinate axes. Various faces of this box may be +open, as required by the geometry of the problem, e.g., for a half-space prob- +lem, the “top” of the box should be open. +4. +Internally, LS-DYNA will partition the entire PML into regions which form the +“faces”, “edges” and “corners” of the above cuboid box, and generate a new +material for each region. This partitioning will be visible in the d3plot file. The +user may safely ignore this partitioning. +5. The layer should have 5-10 elements through its depth. Typically, 5-6 elements +are sufficient if the excitation source is reasonably distant from the layer, and 8- +10 elements if it is close. The size of the elements should be similar to that of +elements in the bounded domain near the layer, and should be small enough to +sufficiently discretize all significant wavelengths in the problem. +6. The nodes on the outer boundary of the layer should be fully constrained. +7. The stress and strain values reported by this material do not have any physical +significance. +*MAT_PML_ELASTIC_FLUID +This is Material Type 230_FLUID. This is a perfectly-matched layer (PML) material +with a pressure fluid constitutive law, to be used in a wave-absorbing layer adjacent to +a fluid material (*MAT_ELASTIC_FLUID) in order to simulate wave propagation in an +unbounded fluid medium. See the Remarks sections of *MAT_PML_ELASTIC (*MAT_- +230) and *MAT_ELASTIC_FLUID (*MAT_001_FLUID) for further details. +5 +6 +7 +8 +Card +1 +Variable +MID +2 +RO +Type +A8 +F +3 +K +F +4 +VC +F +Default +none +none +none +none + VARIABLE +DESCRIPTION +MID +RO +K +VC +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Bulk modulus +Tensor viscosity coefficient +*MAT_PML_ACOUSTIC +This is Material Type 231. This is a perfectly-matched layer (PML) material — an +absorbing layer material used to simulate wave propagation in an unbounded acoustic +medium — and can be used only with the acoustic pressure element formulation +(element type 14). This material implements the 3D version of the Basu-Chopra PML +for anti-plane motion [Basu and Chopra (2003,2004), Basu (2009)]. +4 +5 +6 +7 +8 +Card +1 +Variable +MID +2 +RO +Type +A8 +F +3 +C +F +Default +none +none +none + VARIABLE +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Sound speed +MID +RO +C +Remarks: +1. A layer of this material may be placed at a boundary of a bounded domain to +simulate unboundedness of the domain at that boundary: the layer absorbs and +attenuates waves propagating outward from the domain, without any signifi- +cant reflection of the waves back into the bounded domain. The layer cannot +support any hydrostatic pressure. +2. +It is assumed the material in the bounded domain near the layer is an acoustic +material. The material properties of the layer should be set to the correspond- +ing properties of this material. +3. The layer should form a cuboid box around the bounded domain, with the axes +of the box aligned with the coordinate axes. Various faces of this box may be +open, as required by the geometry of the problem, e.g., for a half-space prob- +lem, the “top” of the box should be open. +4. +Internally, LS-DYNA will partition the entire PML into regions which form the +“faces”, “edges” and “corners” of the above cuboid box, and generate a new +material for each region. This partitioning will be visible in the d3plot file. The +user may safely ignore this partitioning. +5. The layer should have 5-10 elements through its depth. Typically, 5-6 elements +are sufficient if the excitation source is reasonably distant from the layer, and 8- +10 elements if it is close. The size of the elements should be similar to that of +elements in the bounded domain near the layer, and should be small enough to +sufficiently discretize all significant wavelengths in the problem. +6. The nodes on the outer boundary of the layer should be fully constrained. +7. The pressure values reported by this material do not have any physical +significance. +*MAT_BIOT_HYSTERETIC +This is Material Type 232. This is a Biot linear hysteretic material, to be used for +modeling the nearly-frequency-independent viscoelastic behaviour of soils subjected to +cyclic loading, e.g. in soil-structure interaction analysis [Spanos and Tsavachidis (2001), +Makris and Zhang (2000), Muscolini, Palmeri and Ricciardelli (2005)]. The hysteretic +damping coefficient for the model is computed from a prescribed damping ratio by +calibrating with an equivalent viscous damping model for a single-degree-of-freedom +system. The damping increases the stiffness of the model and thus reduces the +computed time-step size. +Card +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +ZT +F +6 +FD +F +7 +8 +Default +none +none +none +none +0.0 +3.25 +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +Damping ratio +Dominant excitation frequency in Hz + VARIABLE +MID +RO +E +PR +ZT +FD +Remarks: +1. The stress is computed as a function of the strain rate as +𝜎(𝑡) = ∫ 𝐶𝑅(𝑡 − 𝜏)𝜀̇(𝜏) +𝑑𝜏 +where +𝐶𝑅(𝑡) = 𝐶 [1 + +2𝜂 +𝐸1(𝛽𝑡)] +with 𝐶 being the elastic isotropic constitutive tensor, 𝜂 the hysteretic damping +factor, and 𝛽 = 2𝜋𝑓𝑑/10, where 𝑓𝑑 is the dominant excitation frequency in Hz. +The function 𝐸1 is given by +∞ +𝐸1(𝑠) = ∫ +e−𝜉 +𝑑𝜉 +For efficient implementation, this function is approximated by a 5-term Prony +series as +𝐸1(𝑠) ≈ ∑ 𝑏𝑘e𝑎𝑘𝑠 +𝑘=1 +such that 𝑏𝑘 > 0. +2. The hysteretic damping factor 𝜂 is obtained from the prescribed damping ratio +𝜍 as +𝜂 = 𝜋𝜍/atan(10) = 2.14𝜍 +by assuming that, for a single degree-of-freedom system, the energy dissipated +per cycle by the hysteretic material is the same as that by a viscous damper, if +the excitation frequency matches the natural frequency of the system. +3. The consistent Young’s modulus for this model is given by +where +𝐸𝑐 = 𝐸 [1 + +2𝜂 +𝑔] +𝑔 = ∑ 𝑏𝑘 +𝑘=1 +𝑎𝑘𝛽Δ𝑡𝑛 +[exp(𝑎𝑘𝛽Δ𝑡𝑛) − 1] +Because 𝑔 > 0, the computed element time-step size is smaller than that for the +corresponding elastic element. Furthermore, the time-step size computed at +any time depends on the previous time-step size. It can be demonstrated that +the new computed time-step size stays within a narrow range of the previous +time-step size, and for a uniform mesh, converges to a constant value. For +𝑓𝑑 = 3.25Hz and 𝜍 = 0.05, the percentage decrease in time-step size can be ex- +pected to be about 12-15% for initial time-step sizes of less than 0.02 secs, and +about 7-10% for initial time-step sizes larger than 0.02 secs. +4. The default value of the dominant frequency is chosen to be valid for earth- +quake excitation. +*MAT_CAZACU_BARLAT +This is Material Type 233. This material model is for Hexagonal Closed Packet (HCP) +metals and is based on the work by Cazacu et al. (2006). This model is capable of +describing the yielding asymmetry between tension and compression for such +materials. Moreover, a parameter fit is optional and can be used to find the material +parameters that describe the experimental yield stresses. The experimental data that +the user should supply consists of yield stresses for tension and compression in the 00 +direction, tension in the 45 and the 90 directions, and a biaxial tension test. +Available options include: + +MAGNESIUM +Including MAGNESIUM invokes a material model developed by the USAMP +consortium to simulate cast Magnesium under impact loading. The model includes rate +effects having a tabulated failure model including equivalent plastic strain to failure as +a function of stress triaxiality and effective plastic strain rate. Element erosion will +occur when the number of integration points where the damage variable has reached +unity reaches some specified threshold (NUMINT). Alternatively a Gurson type failure +model can be activated, which requires less experimental data. +The input of the hardening curve for MAT_233 requires the user to provide the +evolution of the Cazacu-Barlat effective stress as a function of the energy conjugate +plastic strain. With the MAGNESIUM option an alternative option for the hardening +curve is available: von Mises effective stress as a function of equivalent plastic strain, +which is energy conjugate to the von Mises stress. +Finnally the MAGNESIUM option allows for distortional hardening by providing +hardening curves as measured in tension and compression tests. This option is +however incompatible with the activation of rate effects (visco-plasticity). +With the MAGNESIUM option this material model is also available for solid elements. +NOTE: Activating the MAGNESIUM options requires setting +HR = 3 and FIT = 0.0. (Also see below) +Card 1 +1 +Variable +MID +Type +A8 + Card 2 +Variable +Type +1 +A +F + Card 3 +1 +Variable +AOPT +Type +F +2 +RO +F +2 +3 +E +F +3 +4 +PR +F +4 +5 +HR +F +5 +C11 +C22 +C33 +LCID +F +2 +F +3 +I +5 +6 +P1 +F +6 +E0 +F +6 +7 +P2 +F +7 +K +F +7 +8 +ITER +F +8 +P3 +F +8 +F +4 +4 +A1 +F +4 +D1 +F +C12 +C13 +C23 +C44 +F +F +5 +A2 +F +5 +D2 +F +6 +A3 +F +6 +D3 +F +F +7 +F +8 +7 +BETA +8 +FIT +F +I + Card 4 +1 +2 +3 +Variable +Type + Card 5 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +Magnesium Card. Additional card for MAGNESIUM keyword option. + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LC1ID +LC2ID +NUMINT +LCCID +ICFLAG +IDFLAG +LC3ID +EPSFG +Type +I +I +F +I +I +I +I +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +HR +Material Identification number. +Constant Mass density. +Young’s modulus +E.GT.0.0: constant value +E.LT.0.0: load curve ID (–E) which defines the Young’s +modulus as a function of plastic strain. +Poisson’s ratio +Hardening rules: +HR.EQ.1.0: linear hardening (default) +HR.EQ.2.0: exponential hardening (Swift) +HR.EQ.3.0: load curve +HR.EQ.4.0: exponential hardening (Voce) +HR.EQ.5.0: exponential hardening (Gosh) +HR.EQ.6.0: exponential hardening (Hocken-Sherby) +HR must be set to 3 if the MAGNESIUM option is active +P1 +Material parameter: +HR.EQ.1.0: tangent modulus +HR.EQ.2.0: 𝑞, coefficient for exponential hardening law (Swift) +HR.EQ.4.0: 𝑎, coefficient for exponential hardening law (Voce) +HR.EQ.5.0: 𝑞, coefficient for exponential hardening law (Gosh) +HR.EQ.6.0: 𝑎, coefficient +for exponential hardening +law +(Hocket-Sherby) +VARIABLE +DESCRIPTION +P2 +Material parameter: +HR.EQ.1.0: yield stress for the linear hardening law +HR.EQ.2.0: 𝑛, coefficient for (Swift) exponential hardening +HR.EQ.4.0: 𝑐, coefficient for exponential hardening law (Voce) +HR.EQ.5.0: 𝑛, coefficient for exponential hardening law (Gosh) +HR.EQ.6.0: 𝑐, coefficient +for exponential hardening +law +(Hocket-Sherby) +ITER +Iteration flag for speed: +ITER.EQ.0.0: fully iterative +ITER.EQ.1.0: fixed at three iterations. Generally, ITER = 0.0 is +recommended. However, ITER = 1.0 is faster and +may give acceptable results in most problems. +A +C11 +Exponent in Cazacu-Barlat’s orthotropic yield surface (A > 1) +Material parameter : +FIT.EQ.1.0 or EQ.2.0: yield stress for tension in the 00 direction +FIT.EQ.0.0: +material parameter 𝑐11 +C22 +Material parameter : +FIT.EQ.1.0 or EQ.2.0: yield stress for tension in the 45 direction +FIT.EQ.0.0: +material parameter 𝑐22 +C33 +Material parameter : +FIT.EQ.1.0 or EQ.2.0: yield stress for tension in the 90 direction +FIT.EQ.0.0: material parameter 𝑐33 +LCID +Load curve ID for the hardening law (HR.EQ.3.0), Table ID for +rate dependent hardening if the MAGNESIUM option is active +*MAT_CAZACU_BARLAT +DESCRIPTION +E0 +Material parameter: +HR.EQ.2.0: 𝜀0, initial yield strain for exponential hardening +law (Swift) (default = 0.0) +HR.EQ.4.0: 𝑏, coefficient for exponential hardening (Voce) +HR.EQ.5.0: 𝜀0, initial yield strain for exponential hardening +(Gosh), Default = 0.0 +HR.EQ.6.0: 𝑏, coefficient +for exponential hardening +law +(Hocket-Sherby) +K +Material parameter : +FIT.EQ.1.0 or EQ.2.0: yield stress for compression in the 00 +direction +FIT.EQ.0.0: +material parameter (-1 < k<1) +P3 +Material parameter: +HR.EQ.5.0: 𝑝, coefficient for exponential hardening (Gosh) +HR.EQ.6.0: 𝑛, exponent +for exponential hardening +law +(Hocket-Sherby +VARIABLE +AOPT +DESCRIPTION +Material axes option . +AOPT.EQ.0.0: locally +orthotropic with material +axes +determined by element nodes 1, 2 and 4, as with +*DEFINE_COORDINATE_NODES, and then ro- +tated about the shell element normal by the an- +gle BETA. +AOPT.EQ.2.0: globally +orthotropic with material +axes +determined by vectors defined below, as with +*DEFINED_COORDINATE_VECTOR. +AOPT.EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element +normal by an angle BETA, from a line in the +plane of the element defined by the cross prod- +uct of the vector V with the element normal. +AOPT.LT.0.0: the absolute value of AOPT is coordinate system +ID (CID on *DEFINE_COORDINATE_NODES, +*DE- +*DEFINE_COORDINATE_SYSTEM, or +FINE_COORDINATE_VECTOR). + Available +with the R3 release of 971 and later. +Material parameter. If parameter identification (FIT = 1.0) is +turned on C12 is not used. +Material parameter. If parameter identification (FIT = 1.0) is +turned on C13 = 0.0 +Material parameter. If parameter identification (FIT = 1.0) is +turned on C23 = 0.0 +Material parameter +FIT.EQ.1.0 or EQ.2.0: yield stress for the balanced biaxial +tension test. +FIT.EQ.0.0: +material parameter c44 +C12 +C13 +C23 +C44 +A1 - A3 +Components of vector 𝐚 for AOPT = 2.0 +V1 - V3 +Components of vector 𝐯 for AOPT = 3.0 +D1 - D3 +Components of vector 𝐝 for AOPT = 2.0 +BETA +*MAT_CAZACU_BARLAT +DESCRIPTION +Material angle in degrees for AOPT = 0 and 3. NOTE, may be +overridden on the element card, see *ELEMENT_SHELL_BETA +FIT +Flag for parameter identification algorithm: +FIT.EQ.0.0: No parameter identification routine is used. The +variables K, C11, C22, C33, C44, C12, C13 and C23 +are interpreted as material parameters. FIT MUST +be set to zero if MAGNESIUM option is active +FIT.EQ.1.0: Parameter fit is used. The variables C11, C22, C33, +C44 and K are interpreted as yield stresses in the +00, 45, 90 degree directions, the balanced biaxial +tension and the 00 degree compression, respective- +ly. +It is recommended to always check the d3hsp file to see +the fitted parameters before complex jobs are submitted. +FIT.EQ.2.0: Same as EQ.1.0 but also produce contour plots of +the yield surface. For each material three LS- +PrePost ready xy-data files are created; Con- +tour1_𝑛, Contour2_𝑛 and Contour3_𝑛 where 𝑛 +equal the material number. +Load curve ID giving equivalent plastic strain to failure as a +function of stress triaxiality or a table ID giving plastic strain to +failure as a function of Lode parameter and stress triaxiality +(solids) +Load curve ID giving equivalent plastic strain to failure as a +function of equivalent plastic strain rate, the failure strain will be +computed as the product of the values on LC1ID and LC2ID +Number of through thickness integration points which must fail +before the element is deleted (inactive for solid elements) +Load curve ID giving effective stress in function of plastic strain +obtained from a compression stress, input of this load curve will +activate distortional hardening and is NOT compatible with the +use of strain rate effects +LC1ID +LC2ID +NUMINT +LCCID +DESCRIPTION +Automated input conversion flag. If ICFLAG = 0 then the load +curves provided under LCID and LCCID contain Cazacu-Barlat +effective stress as a function of energy conjugate plastic strain. If +ICFLAG = 1 then both load curves are given in terms of von +Mises stress versus equivalent plastic strain +Damage flag. If IDFLAG = 0 the failure model is of the Johnson +Cook type and requires LC1ID and LC2ID as additional input. If +IDFLAG = 1 the failure model is of the Gurson type and requires +LC3ID and EPSFG as additional input +Load curve giving the critical void fraction of the Gurson model +as a function of the plastic strain to failure measured in the +uniaxial tensile test +Plastic strain to failure measured in the uniaxial tensile test, this +value is used by the Gurson type failure model only. + VARIABLE +ICFLAG +IDFLAG +LC3ID +EPSFG +Remarks: +The material model #233 (MAT_CAZACU_BARLAT) is aimed for modeling materials +with strength differential and orthotropic behavior under plane stress. The yield +condition includes a parameter 𝑘 that describes the asymmetry between yield in tension +and compression. Moreover, to include the anisotropic behavior the stress deviator 𝐒 +undergoes a linear transformation. The principal values of the Cauchy stress deviator +are substituted with the principal values of the transformed tensor 𝐙, which is +represented as a vector field, defined as: +where +nents𝑆𝐼 = (���11, 𝑠22, 𝑠33, 𝑠12), +the +𝐒is +field +𝐙 = 𝐂𝐒 +(233.1) +comprised +of +the +four +stresses +deviator +𝐬 = σ − +tr(σ)δ, +where tr(σ) is the trace of the Cauchy stress tensor and δ is the Kronecker delta. For the +2D plane stress condition, the orthotropic condition gives 7 independent coefficients. +The tensor 𝐂 is represented by the 4𝑥4 matrix +𝐶𝐼𝐽 = +𝑐12 +𝑐22 +𝑐23 +𝑐13 +𝑐23 +𝑐33 +𝑐11 +𝑐12 +𝑐13 +⎜⎜⎜⎜⎜⎛ +⎝ +⎟⎟⎟⎟⎟⎞ +. +𝑐44⎠ +The principal values of 𝐙 are denoted Σ1, Σ2, Σ3 and are given as the eigenvalues to the +matrix composed by the components Σ𝑥𝑥, Σ𝑦𝑦, Σ𝑧𝑧, Σ𝑥𝑦through +where +Σ1 = +Σ2 = +(Σ𝑥𝑥 + Σ𝑦𝑦 + √(Σ𝑥𝑥 − Σ𝑦𝑦) ++ 4Σ𝑥𝑦 +2 ) , +(Σ𝑥𝑥 + Σ𝑦𝑦 − √(Σ𝑥𝑥 − Σ𝑦𝑦) ++ 4Σ𝑥𝑦 +2 ) , +Σ3 = Σ𝑧𝑧 +3Σ𝑥𝑥 = (2𝑐11 − 𝑐12 − 𝑐13)𝜎𝑥𝑥 + (−𝑐11 + 2𝑐12 − 𝑐13)𝜎𝑦𝑦, +3Σ𝑦𝑦 = (2𝑐12 − 𝑐22 − 𝑐23)𝜎𝑥𝑥 + (−𝑐12 + 2𝑐22 − 𝑐23)𝜎𝑦𝑦, +3Σ𝑧𝑧 = (2𝑐13 − 𝑐23 − 𝑐33)𝜎𝑥𝑥 + (−𝑐13 + 2𝑐23 − 𝑐33)𝜎𝑦𝑦, +Σ𝑥𝑦 = 𝑐44𝜎12 +Note that the symmetry of Σ𝑥𝑦 follows from the symmetry of the Cauchy stress tensor. +The yield condition is written on the following form: +𝑓 (Σ, 𝑘, 𝜀ep) = 𝜎eff(Σ1, Σ2, Σ3, 𝑘) − 𝜎𝑦(𝜀ep) ≤ 0 +(233.2) +where 𝜎𝑦(𝜀ep) is a function representing the current yield stress dependent on current +effective plastic strain and 𝑘 is the asymmetric parameter for yield in compression and +tension. The effective stress 𝜎effis given by +𝜎eff = [(|Σ1| − 𝑘Σ1)𝑎 + (|Σ2| − 𝑘Σ2)𝑎 + (∣Σ3∣ − 𝑘Σ3)𝑎] +𝐶 represent the yield stress along the rolling +𝑇 and 𝜎00 +where 𝑘 ∈ [−1,1], 𝑎 ≥ 1. Now, let 𝜎00 +𝑇 and +(00 degree) direction in tension and compression, respectively. Furthermore let 𝜎45 +𝑇 be +𝑇 represent the yield stresses in the 45 and the 90 degree directions, and last let 𝜎𝐵 +𝜎90 +the balanced biaxial yield stress in tension. Following Cazacu et al. (2006) the yield +stresses can easily be derived. +(233.3) +𝑎⁄ +To simplify the equations it is preferable to make the following definitions: +Φ1 = +Φ2 = +Φ3 = +(2𝑐11 − 𝑐12 − 𝑐13) +Ψ1 = +(2𝑐12 − 𝑐22 − 𝑐23) +and +Ψ2 = +(2𝑐13 − 𝑐23 − 𝑐33) +Ψ3 = +(−𝑐11 + 2𝑐12 − 𝑐13) +(−𝑐12 + 2𝑐22 − 𝑐23) +(−𝑐13 + 2𝑐23 − 𝑐33) +The yield stresses can now be written as: +1. +In the 00 degree direction: +𝑇 = [ +𝜎00 +𝐶 = [ +𝜎00 +(𝜎eff)𝑎 +(|Φ1| − 𝑘Φ1)𝑎 + (|Φ2| − 𝑘Φ2)𝑎 + (∣Φ3∣ − 𝑘Φ3)𝑎] +(𝜎eff)𝑎 +(|Φ1| + 𝑘Φ1)𝑎 + (|Φ2| + 𝑘Φ2)𝑎 + (∣Φ3∣ + 𝑘Φ3)𝑎] +𝑎⁄ +, +𝑎⁄ +2. +In the 45 degree direction: +𝑇 = [ +𝜎45 +(𝜎eff)𝑎 +(|Λ1| − 𝑘Λ1)𝑎 + (|Λ2| − 𝑘Λ2)𝑎 + (∣Λ3∣ − 𝑘Λ3)𝑎] +𝑎⁄ +where +Λ1 = +Λ2 = +Λ3 = +[Φ1 + Φ2 + Ψ1 + Ψ2 + √(Φ1 + Ψ1 − Φ2 − Ψ2)2 + 4𝑐44 +2 ] , +[Φ1 + Φ2 + Ψ1 + Ψ2 − √(Φ1 + Ψ1 − Φ2 − Ψ2)2 + 4𝑐44 +2 ] , +[Φ3 + Ψ3]. +3. +In the 90 degree direction: +𝑇 = [ +𝜎90 +(𝜎eff)𝑎 +(|Ψ1| − 𝑘Ψ1)𝑎 + (|Ψ2| − 𝑘Ψ2)𝑎 + (∣Ψ3∣ − 𝑘Ψ3)𝑎] +𝑎⁄ +4. +In the balanced biaxial yield occurs when both 𝜎𝑥𝑥 and 𝜎𝑦𝑦are equal to: +𝑇 = [ +𝜎𝐵 +(𝜎eff)𝑎 +(|Ω1| − 𝑘Ω1)𝑎 + (|Ω2| − 𝑘Ω2)𝑎 + (∣Ω3∣ − 𝑘Ω3)𝑎] +𝑎⁄ +where +(233.4) +(233.5) +(233.6) +(233.7) +Ω1 = +Ω2 = +Ω3 = +(𝑐11 + 𝑐12 − 2𝑐13) +(𝑐12 + 𝑐22 − 2𝑐23) +(𝑐13 + 𝑐23 − 2𝑐33) +Hardening laws: +The implemented hardening laws are the following: +1. The Swift hardening law +2. The Voce hardening law +3. The Gosh hardening law +4. The Hocket-Sherby hardening law +5. A loading curve, where the yield stress is given as a function of the effective +plastic strain +The Swift’s hardening law can be written +where 𝑞 and 𝑛 are material parameters. +𝜎𝑦(𝜀ep) = 𝑞(𝜀0 + 𝜀ep) +The Voce’s equation says that the yield stress can be written in the following form +𝜎𝑦(𝜀ep) = 𝑎 − 𝑏𝑒−𝑐𝜀ep +where 𝑎, 𝑏and 𝑐 are material parameters. The Gosh’s equation is similar to Swift’s +equation. They only differ by a constant +𝜎𝑦(𝜀ep) = 𝑞(𝜀0 + 𝜀ep) +− 𝑝 +where 𝑞, 𝜀0, 𝑛 and 𝑝 are material constants. The Hocket-Sherby equation resemblance +the Voce’s equation, but with an additional parameter added +𝜎𝑦(𝜀ep) = 𝑎 − 𝑏𝑒−𝑐𝜀ep +where 𝑎, 𝑏, 𝑐 and 𝑛 are material parameters. +Constitutive relation and material stiffness: +The classical elastic constitutive equation for linear deformations is the well-known +Hooke’s law. This relation written in a rate formulation is given by +𝛔̇ = 𝐃ε̇𝑒 +(233.8) +where ε𝑒 is the elastic strain and 𝐃 is the constitutive matrix. An over imposed dot +indicates differentiation respect to time. Introducing the total strain εand the plastic +strain ε𝑝, Eq. (233.8) is classically rewritten as +𝛔̇ = 𝐃(𝜺̇ − 𝜺̇𝑝) +(233.9) +*MAT_233 +𝐃 = +1 − 𝜈2 +⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎛1 +⎝ +1 − 𝑣 +1 − 𝑣 +⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎞ +1 − 𝑣 +2 ⎠ + and (ε̇ − ε̇𝑝) = +⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎛ +⎝ +11 +𝜀̇11 − (𝜀̇𝑝) +𝜀̇22 − (𝜀̇𝑝) +22 +2[𝜀̇12 − (𝜀̇𝑝) +12 +2[𝜀̇13 − (𝜀̇𝑝) +13 +2[𝜀̇23 − (𝜀̇𝑝) +23 +⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎞ +] +] +]⎠ +. +The parameters 𝐸and 𝑣 are the Young’s modulus and Poisson’s ratio, respectively. +The material stiffness 𝐃𝑝 that is needed for e.g., implicit analysis can be calculated from +(233.9) as +𝐃𝑝 = +∂𝛔̇ +∂ε̇ +. +The associative flow rule for the plastic strain is usually written +and the consistency condition reads +ε̇𝑝 = 𝜆̇ +∂𝑓 +∂𝛔 +d𝑓 +d𝛔 +𝛔̇ + +d𝑓 +dεep +ε̇ep = 0. +(233.10) +(233.10) +(233.11) +Note that the centralized “dot” means scalar product between two vectors. Using +standard calculus one easily derives from (1.9), (1.10) and (1.11) an expression for the +stress rate +𝛔̇ = +𝐃 − +⎡ +⎢ +⎢ +⎢ +⎢ +⎣ +(𝐃 +d𝑓 +d𝛔 +) ⋅ (𝐃 +𝑑𝑓 +𝑑𝛔 +⋅ (𝐃 +d𝑓 +d𝛔 +) − +) +d𝑓 +⎤ +⎥ +d𝝈 +⎥ +⎥ +d𝑓 +⎥ +dε𝑒𝑝⎦ +ε̇ +(233.12) +That means that the material stiffness used for implicit analysis is given by +𝐃𝑝 = 𝐃 − +(𝐃 +d𝑓 +d𝛔 +) ⋅ (𝐃 +d𝑓 +d𝛔 +⋅ (𝐃 +d𝑓 +d𝝈 +) − +) +d𝑓 +d𝛔 +d𝑓 +d𝜀ep +. +(233.13) +To be able to do a stress update we need to calculate the tangent stiffness and the +derivative with respect to the corresponding hardening law. +When a suitable hardening law has been chosen the corresponding derivative is simple +and will be left out from this document. However, the stress gradient of the yield +surface is more complicated and will be outlined here. +∂𝑓 +𝜕σ11 += +𝜕𝑓 +𝜕Σ3 +𝜕𝑓 +⎜⎛1 + +⎢⎡ +𝜕Σ1 ⎣ +⎝ +Σ𝑥𝑥 − Σ𝑦𝑦 +√Σ𝑇 ⎠ +⎟⎞ Φ1 + +⎜⎛1 − +⎝ +Σ𝑥𝑥 − Σ𝑦𝑦 +⎟⎞ Φ2 +⎥⎤ +⎦ +√Σ𝑇 ⎠ ++ +𝜕𝑓 +⎜⎛1 − +⎢⎡ +𝜕Σ2 ⎣ +⎝ +Σ𝑥𝑥 − Σ𝑦𝑦 +⎟⎞ Φ1 + +⎜⎛1 + +⎝ +√Σ𝑇 ⎠ +Σ𝑥𝑥 − Σ𝑦𝑦 +√Σ𝑇 ⎠ +⎟⎞ Φ2 +(233.14) +⎥⎤ + Φ3 +⎦ +𝜕𝑓 +𝜕𝜎22 += +𝜕𝑓 +⎜⎛1 + +⎢⎡ +𝜕Σ1 ⎣ +⎝ +Σ𝑥𝑥 − Σ𝑦𝑦 +⎟⎞ Ψ1 + +⎜⎛1 − +⎝ +Σ𝑥𝑥 − Σ𝑦𝑦 +⎟⎞ Ψ2 +⎥⎤ +⎦ +√Σ𝑇 ⎠ +√Σ𝑇 ⎠ ++ +𝜕𝑓 +⎜⎛1 − +⎢⎡ +𝜕Σ2 ⎣ +⎝ +Σ𝑥𝑥 − Σ𝑦𝑦 +⎟⎞ Ψ1 + +⎜⎛1 + +⎝ +√Σ𝑇 ⎠ +Σ𝑥𝑥 − Σ𝑦𝑦 +⎟⎞ Ψ2 +√Σ𝑇 ⎠ +and the derivative with respect to the shear stress component is +𝜕𝑓 +𝜕𝜎12 += 𝑐44 +2Σ𝑥𝑦 +√Σ𝑇 +( +𝜕𝑓 +𝜕Σ1 +− +𝜕𝑓 +𝜕Σ2 +) +Σ𝑇 = (Σ𝑥𝑥 − Σ𝑦𝑦) ++ 4Σ𝑥𝑦 +where +and +(233.15) +𝜕𝑓 +𝜕Σ3 +⎥⎤ + +⎦ +Ψ3 +(233.16) +(233.17) +𝑎−1 += 𝑓 (Σ, 𝑘, 𝜀𝑒𝑝) +𝜕𝑓 +𝜕Σ𝑖 +(|Σ𝑖| − 𝑘Σ𝑖)𝑎−1(sgn(Σ𝑖) − 𝑘) for 𝑖 = 1,2,3 +(233.18) +Implementation: +Assume that the stress and strain is known at time 𝑡𝑛. A trial stress σ̃𝑛+1 at time 𝑡𝑛+1 is +calculated by assuming a pure elastic deformation, i.e., +𝛔̃𝑛+1 = 𝛔𝑛 + 𝐃(ε𝑛+1 − ε𝑛) +(233.19) +Now, if 𝑓 (Σ, 𝑘, 𝜀𝑒𝑝) ≤ 0 the deformation is pure elastic and the new stress and plastic +strain are determined as +𝛔𝑛+1 = 𝛔̃𝑛+1 +𝑛+1 = 𝜀ep +𝜀ep +and the thickness strain increment is given by +Δ𝜀33 = 𝜀33 +𝑛+1 − 𝜀33 +𝑛 = − +1 − 𝑣 +(Δ𝜀11 + Δ𝜀22) +(233.20) +(233.21) +If the deformation is not pure elastic the stress is not inside the yield surface and a +plastic iterative procedure must take place. +1. Set 𝑚 = 0, 𝛔(0) +𝑛+1 = 𝛔̃𝑛+1, 𝜀ep(0) +𝑛+1 = 𝜀ep +𝑛 and Δ𝜀11 +𝑝(0) = Δ𝜀22 +𝑝(0) = 0 +2. Determine the plastic multiplier as +Δ𝜆 = +d𝑓 +d𝛔 +𝑛+1 ) +𝑛+1, 𝜀ep(𝑚) +𝑓 (𝛔(𝑚) +d𝑓 +d𝛔 +(σ(𝑚) +𝑛+1) ⋅ 𝐃 +𝑛+1) − +(σ(𝑚) +d𝑓 +d𝜀ep +𝑛+1 ) +(𝜀ep(𝑚) +(233.22) +3. Perform a plastic corrector step: 𝛔(𝑚+1) +increments in plastic strain according to +𝑛+1 = 𝛔(𝑚) +𝑛+1 − Δ𝜆𝐃 +𝑛+1 +𝜀ep(𝑚+1) += 𝜀ep(𝑚) +𝑛+1 + Δ𝜆 +Δ𝜀11 +𝑝(𝑛+1) = Δ𝜀11 +𝑝(𝑛) + Δ𝜆 +Δ𝜀22 +𝑝(𝑛+1) = Δ𝜀22 +𝑝(𝑛) + Δ𝜆 +∂𝑓 +𝜕𝜎11 +𝜕𝑓 +𝜕𝜎22 +(𝜎(𝑚) +𝑛+1) +(𝜎(𝑚) +𝑛+1) +4. +If ∣𝑓 (σ(𝑚+1) +𝑛+1 +, 𝜀ep +𝑛 )∣ < tol or 𝑚 = 𝑚max; stop and set +, +, +𝑛+1 +𝑛+1 +𝛔𝑛+1 = 𝛔(𝑚+1) +𝑛+1 = 𝜀ep(𝑚+1) +𝜀ep +𝑝 = Δ𝜀11 +𝑝 = Δ𝜀22 +Δ𝜀11 + Δ𝜀22 +𝑝(𝑚+1), +𝑝(𝑚+1), +d𝑓 +d𝛔 (𝛔(𝑚) +𝑛+1) and find the +(233.23) +(233.24) +otherwise set 𝑚 = 𝑚 + 1and return to 2. +The thickness strain increment is for plastic yield calculated as +Δ𝜀33 = − +1 − 𝑣 +(Δ𝜀11 + Δ𝜀22) − (1 − +1 − 𝑣 +) (Δ𝜀11 +𝑝 ) +𝑝 + Δ𝜀22 +(233.25) +The following history variables will be stored for the MAGNESIUM option: +HV1 +HV6 +HV7 +HV8 +HV9 +equivalent plastic strain (energy conjugate to Cazacu-Barlat effective stress) +damage +plastic strain to failure +number of IP that failed +equivalent plastic strain (energy conjugate to von Mises stress) +effective stress (Cazacu-Barlat) +HV10 +HV11 Gurson damage +HV12 +HV13 +HV14 +void fraction +void fraction star +equivalent plastic strain (energy conjugate to von Mises stress) +*MAT_VISCOELASTIC_LOOSE_FABRIC +This is Material Type 234 developed and implemented by Tabiei et al [2004]. The model +is a mechanism incorporating the crimping of the fibers as well as the trellising with +reorientation of the yarns and the locking phenomenon observed in loose fabric. The +equilibrium of the mechanism allows the straightening of the fibers depending on the +fiber tension. The contact force at the fiber cross over point determines the rotational +friction dissipating a part of the impact energy. The stress-strain relationship is +viscoelastic based on a three-element model. The failure of the fibers is strain rate +dependent. *DAMPING_PART_MASS is recommended to be used in conjunction with +this material model. This material is valid for modeling the elastic and viscoelastic +response of loose fabric used in body armor, blade containments, and airbags. +fill yarn +warp yarn +Figure M234-1. Representative Volume Cell (RVC) of the model + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +Variable +1 +TA +Type +F +2 +RO +F +2 +W +F +3 +E1 +F +3 +s +F +4 +E2 +F +4 +T +F +5 +G12 +F +5 +H +F +6 +EU +F +6 +S +F +7 +THL +F +7 +8 +THI +F +8 +EKA +EUA +F +4 +5 +6 +7 +8 +G23 +EKB +AOPT +*MAT_234 + Card 3 +1 +Variable +VMB +Type +F + Card 4 +1 +2 +C +F +2 +F +3 +F +4 +Variable Not used Not used Not used +A1 +Type + Card 5 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +F +4 +D1 +F +F +5 +A2 +F +5 +D2 +F +6 +A3 +F +6 +D3 +F +7 +8 +7 +8 + VARIABLE +DESCRIPTION +MID +RO +E1 +E2 +G12 +EU +THL +THI +TA +W +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +𝐸1, Young’s modulus in the yarn axial-direction. +𝐸2, Young’s modulus in the yarn transverse-direction. +𝐺12, Shear modulus of the yarns. +Ultimate strain at failure. +Yarn locking angle. +Initial braid angle. +Transition angle to locking. +Fiber width. +VARIABLE +DESCRIPTION +S +T +H +S +EKA +EUA +VMB +C +G23 +Ekb +AOPT +Span between the fibers. +Real fiber thickness. +Effective fiber thickness. +Fiber cross-sectional area. +Elastic constant of element "a". +Ultimate strain of element "a". +Damping coefficient of element "b". +Coefficient of friction between the fibers. +transverse shear modulus. +Elastic constant of element "b" +Material axes option . +AOPT.EQ.0.0: locally +orthotropic with material +axes +determined by element nodes 1, 2 and 4, as with +*DEFINE_COORDINATE_NODES. +AOPT.EQ.2.0: globally +orthotropic with material +axes +determined by vectors defined below, as with +*DEFINED_COORDINATE_VECTOR. +AOPT.EQ.3.0: locally orthotropic material axes defined by the +cross product of the vector V with the element +normal. +AOPT.LT.0.0: the absolute value of AOPT is coordinate system +ID (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM, or +*DE- +FINE_COORDINATE_VECTOR). + Available +with the R3 release of 971 and later. +45o +45o +a) +b) +min +min +c) +Figure M234-2. Plain woven fabric as trellis mechanism: a) initial state; b) +slightly stretched in bias direction; c) stretched to locking. +Remarks: +The parameters of the Representative Volume Cell (RVC) are: the yarn span, s, the +fabric thickness, t, the yarn width, w, and the yarn cross-sectional area, 𝐴. The initially +orthogonal yarns are free to rotate up to some +angle and after that the lateral contact between the yarns causes the locking of the trellis +mechanism and the packing of the yarns .The minimum braid angle, +𝜃min, can be calculated from the geometry and the architecture of the fabric material +having the yarn width, 𝑤, and the span between the yarns, 𝑠: +sin(2𝜃min) = +The other constrain angles as the locking range angle, 𝜃lock, and the maximum braid +angle, 𝜃max, are easy to be determined then: +𝜃𝑙𝑜𝑐𝑘 = 45° − 𝜃min , 𝜃max = 45° + 𝜃lock +The material behavior of the yarn can be simply described by a combination of one +Maxwell element without the dashpot and one Kelvin-Voigt element. The 1-D model of +viscoelasticity is shown in the following figure. + The differential equation of +viscoelasticity of the yarns can be derived from the model equilibrium as in the +following equation: +(𝐾𝑎 + 𝐾𝑏)𝜎 + 𝜇𝑏𝜎̇ = 𝐾𝑎𝐾𝑏𝜀 + 𝜇𝑏𝐾𝑎𝜀̇ +σ, ε +Ka +σ , ε +σ , ε +Kb +σ, ε +Figure M234-3. Three-element visvoelasticity model +The input parameters for the viscoelasticity model of the material are only the static +Young’s modulus E1, the Hookian spring coefficient (EKA) 𝐾𝑎, the viscosity coefficient +(VMB) 𝜇𝑏, the static ultimate strain (EU) 𝜀max, and the Hookian spring ultimate strain +(EUA)𝜀𝑎max. The other parameters can be obtained as follows: +𝐾𝑏 = +𝜀𝑏max = +𝐾𝑎𝐸1 +𝐾𝑎 − 𝐸1 +𝐾𝑎 − 𝐸1 +𝐾𝑎 +𝜀max +Applying the Eq. (18) for the fill and the warp yarns, we obtain the stress increments in +the yarns, Δ𝜎𝑓 and Δ𝜎𝑤,. The stress in the yarns is updated for the next time step: +(𝑛), +(𝑛) +(𝑛+1) = 𝜎𝑤 +𝜎𝑤 +(𝑛) + Δ𝜎𝑤 +(𝑛+1) = 𝜎𝑓 +𝜎𝑓 +(𝑛) + Δ𝜎𝑓 +We can imagine that the RVC is smeared to the parallelepiped in order to transform the +stress acting on the yarn cross-section to the stress acting on the element wall. The +thickness of the membrane shell element used should be equal to the effective thickness, +𝑡𝑒, that can be found by dividing the areal density of the fabric by its mass density. The +in-plane stress components acting on the RVC walls in the material direction of the +yarns are calculated as follows for the fill and warp directions: +(𝑛+1)𝑆 +2𝜎𝑓 +(𝑛+1) = +𝜎𝑓11 +𝑠𝑡𝑒 +(𝑛) + 𝛼𝐸2Δ𝜀𝑓22 +(𝑛+1) = 𝜎𝑓22 +𝜎𝑓22 +(𝑛) +(𝑛+1) = 𝜎𝑓12 +𝜎𝑓12 +(𝑛) + 𝛼𝐺12Δ𝜀𝑓12 +(𝑛) +2𝜎𝑤 +𝜎𝑤11 +(𝑛+1) = +(𝑛+1)𝑆 +𝑠𝑡𝑒 +(𝑛) + 𝛼𝐸2Δ𝜀𝑤22 +(𝑛+1) = 𝜎𝑤22 +𝜎𝑤22 +(𝑛) +(𝑛+1) = 𝜎𝑤12 +𝜎𝑤12 +(𝑛) + 𝛼𝐺12Δ𝜀𝑤12 +(𝑛) +lock +lock +Δθ +Δθ +min +45o +max +Figure M234-4. The lateral contact factor as a function of average braid angle +θ. +where E2 is the transverse Young’s modulus of the yarns, 𝐺12 is the longitudinal shear +modulus, and α is the lateral contact factor. The lateral contact factor is zero when the +trellis mechanism is open and unity if the mechanism is locked with full lateral contact +between the yarns. There is a transition range, Δ𝜃 × TA, of the average braid angle 𝜃 in +which the lateral contact factor, 𝛼, is a linear function of the average braid angle. The +graph of the function 𝛼(𝜃) is shown in Fig. M234-4. +*MAT_MICROMECHANICS_DRY_FABRIC +This is Material Type 235 developed and implemented by Tabiei et al [2001]. The +the +material model derivation utilizes +homogenization technique usually used in composite material models. The model +accounts for reorientation of the yarns and the fabric architecture. The behavior of the +flexible fabric material is achieved by discounting the shear moduli of the material in +free state, which allows the simulation of the trellis mechanism before packing the +yarns. This material is valid for modeling the elastic response of loose fabric used in +inflatable structures, parachutes, body armor, blade containments, and airbags. +the micro-mechanical approach and +2 +RO +F +2 +3 +E1 +F +3 +4 +E2 +F +4 +5 +6 +7 +8 +G12 +G23 +V12 +V23 +F +5 +F +6 +F +7 +F +8 +THI +THL +BFI +BWI +DSCF +CNST +ATLR +F +2 +F +3 +F +4 +F +5 +Variable +VMB +VME +TRS +FFLG +AOPT +Type +F + Card 4 +1 +F +2 +F +3 +F +4 +Variable Not used Not used Not used +A1 +Type +F +F +5 +A2 +F +F +7 +F +8 +7 +8 +F +6 +6 +A3 +F + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +Variable +1 +XT +Type +F + Card 3 +Variable +1 +V1 +Type +F +*MAT_MICROMECHANICS_DRY_FABRIC +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 + VARIABLE +DESCRIPTION +MID +RO +E1 +E2 +G12 +G23 +V12 +V23 +XT +THI +THL +BFI +BWI +DSCF +CNST +ATLR +VME +VMS +TRS +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +𝐸1, Young’s modulus of the yarn in axial-direction. +𝐸2, Young’s modulus of the yarn in transverse-direction. +𝐺12, shear modulus of the yarns. +𝐺23, transverse shear modulus of the yarns. +Poisson’s ratio. +Transverse Poisson’s ratio. +Stress or strain to failure . +Initial brade angle. +Yarn locking angle. +Initial undulation angle in fill direction. +Initial undulation angle in warp direction. +Discount factor +Reorientation damping constant +Angle tolerance for locking +Viscous modulus for normal strain rate +Viscous modulus for shear strain rate +Transverse shear modulus of the fabric layer +Figure M235-1. Yarn orientation schematic. + VARIABLE +DESCRIPTION +FFLG +Flag for stress-based or strain-based failure +EQ.0: XT is a stress to failure +NE.0: XT is a strain to failure +AOPT +Material axes option . +AOPT.EQ.0.0: locally +orthotropic with material +axes +determined by element nodes 1, 2 and 4, as with +*DEFINE_COORDINATE_NODES. +AOPT.EQ.2.0: globally +orthotropic with material +axes +determined by vectors defined below, as with +*DEFINED_COORDINATE_VECTOR. +AOPT.EQ.3.0: locally orthotropic material axes defined by the +cross product of the vector V with the element +normal. +AOPT.LT.0.0: the absolute value of AOPT is coordinate system +ID (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM, or +*DE- +FINE_COORDINATE_VECTOR). + Available +with the R3 release of 971 and later. +A1 - A3 +Components of vector 𝐚 for AOPT = 2.0 +V1 - V3 +Components of vector 𝐯 for AOPT = 3.0 +D1 - D3 +Components of vector 𝐝 for AOPT = 2.0 +Remarks: +The Representative Volume Cell (RVC) approach is utilized in the micro-mechanical +model development. The direction of the yarn in each sub-cell is determined by two +angles – the braid angle, 𝜃 (the initial braid angle is 45 degrees), and the undulation angle +of the yarn, which is different for the fill and warp-yarns, 𝛽𝑓 and 𝛽𝑤 (the initial +undulations are normal few degrees), respectively. The starting point for the +homogenization of the material properties is the determination of the yarn stiffness +matrices. +The elasticity tensor is given by +[𝐶′] = [𝑆′]−1 = +𝐸1 +𝜈12 +𝐸1 +𝜈12 +𝐸1 +− +− +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ + 0 + 0 + 0 +− +− +𝜈12 +𝐸1 +𝐸2 +𝜈23 +𝐸2 +− +− +𝜈12 +𝐸1 +𝜈23 +𝐸2 +𝐸2 + 0 + 0 + 0 + 0 + 0 +𝜇𝐺12 + 0 + 0 + 0 + 0 + 0 + 0 + 0 +𝜇𝐺23 + 0 + 0 + 0 + 0 +−1 + 0 + 0 + 0 +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +𝜇𝐺12⎦ + 0 + 0 +where 𝐸1, 𝐸2, 𝜈12, 𝜈23, 𝐺12 and 𝐺23 are Young’s moduli, Poisson’s ratios, and the +shear moduli of the yarn material, respectively. 𝜇 is a discount factor, which is function +of the braid angle, 𝜃, and has value between 𝜇0 and 1 as shown in the next figure. +Initially, in free stress state, the discount factor is a small value (DSCF = 𝜇0 A 1) and the +material has very small resistance to shear deformation if any. +45o +45o +Plain Woven Fabric: Free State +Representative + Volume Cell +Plain Woven Fabric: Stretched +min +min +Plain Woven Fabric: Compacted +When the locking occurs, the fabric yarns are packed and they behave like elastic +media. The discount factor is unity as shown in the next figure. The micro-mechanical +model is developed to account for the reorientation of the yarns up to the locking angle. +The locking angle, 𝜃lock, can be obtained from the yarn width and the spacing parameter +of the fabric using simple geometrical relationship. The transition range, Δ𝜃 (angle +tolerance for locking), can be chosen to be as small as possible, but big enough to +prevent high frequency oscillations in transition to compacted state and depends on the +range to the locking angle and the dynamics of the simulated problem. Reorientation +damping constant is defined to damp some of the high frequency oscillations. A simple +rate effect is added by defining the viscous modulus for normal or shear strain rate +. +(VMB*𝜀11 or 22 +. + for normal components and VMS*𝜀12 + for the shear components). +fill yarn +qf +qw +locking area +warp yarn +RVC +dn +45o +up +lock +lock +Locking Angles +lock +lock +Δθ +Δθ +dn +45o +up +Discount factor as a function of braid angle, θ +*MAT_236 +This is Material Type 236 developed by Carney, Lee, Goldberg, and Santhanam [2007]. +This model simulates silicon carbide coating on Reinforced Carbon-Carbon (RCC), a +ceramic matrix and is based upon a quasi-orthotropic, linear-elastic, plane-stress model. +Additional constitutive model attributes include a simple (i.e. non-damage model +based) option that can model the tension crack requirement: a “stress-cutoff” in tension. +This option satisfies the tension crack requirements by limiting the stress in tension but +not compression, and having the tensile “yielding” (i.e. the stress-cutoff) be fully +recoverable – not plasticity or damage based. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +Variable +1 +PR +Type +F + VARIABLE +MID +2 +RO +F +2 +G +F +3 +E0 +F +3 +4 +E1 +F +4 +5 +E2 +F +5 +6 +E3 +F +6 +7 +E4 +F +7 +8 +E5 +F +8 +G_SCL +TSL +EPS_TAN +F +F +F +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +E0 +E1 +E2 +E3 +E4 +E5 +E0, See Remarks below. +E1, See Remarks below. +E2, See Remarks below. +E3, See Remarks below. +E4, See Remarks below. +E5, Young’s modulus of the yarn in transverse-direction. +*MAT_SCC_ON_RCC +DESCRIPTION +PR +G +Poisson’s ratio. +Shear modulus +G_SCL +Shear modulus multiplier (default = 1.0). +TSL +Tensile limit stress +EPS_TAN +Strain at which E = tangent to the polynomial curve. +Remarks: +This model for the silicon carbide coating on RCC is based upon a quasi-orthotropic, +linear-elastic, plane-stress model, given by: +{⎧𝜎1 +}⎫ +𝜎2 +𝜏12⎭}⎬ +⎩{⎨ += +⎡ +1 − 𝜈2 +⎢ +⎢ +𝜈𝐸 +⎢ +⎢ +1 − 𝜈2 + 0 +⎣ +𝜈𝐸 +1 − 𝜈2 +1 − 𝜈2 + 0 +{⎧𝜀1 +}⎫ +𝜀2 +𝛾12⎭}⎬ +⎩{⎨ + 0 +⎤ +⎥ +⎥ +⎥ +⎥ +𝐺12⎦ + 0 +Additional constitutive model requirements include a simple (i.e. non-damage model +based) option that can model the tension crack requirement: a “stress-cutoff” in tension. +This option satisfies the tension crack requirements by limiting the stress in tension but +not compression, and having the tensile “yielding” (i.e. the stress-cutoff) be fully +recoverable – not plasticity or damage based. +The tension stress-cutoff separately resets the stress to a limit value when it is exceeded +in each of the two principal directions. There is also a strain-based memory criterion +that ensures unloading follows the same path as loading: the “memory criterion” is the +tension stress assuming that no stress cutoffs were in effect. In this way, when the +memory criterion exceeds the user-specified cutoff stress, the actual stress will be set to +that value. When the element unloads and the memory criterion falls back below the +stress cutoff, normal behavior resumes. Using this criterion is a simple way to ensure +that unloading does not result in any hysteresis. The cutoff criterion cannot be based on +an effective stress value because effective stress does not discriminate between tension +and compression, and also includes shear. This means that the in plane, 1- and 2- +directions must be modeled as independent to use the stress cutoff. Because the +Poisson’s ratio is not zero, this assumption is not true for cracks that may arbitrarily lie +along any direction. However, careful examination of damaged RCC shows that +generally, the surface cracks do tend to lie in the fabric directions, meaning that cracks +tend to open in the 1- or the 2- direction independently. So the assumption of +directional independence for tension cracks may be appropriate for the coating because +of this observed orthotropy. +The quasi-orthotropic, linear-elastic, plane-stress model with tension stress cutoff (to +simulate tension cracks) can model the as-fabricated coating properties, which do not +show nonlinearities, but not the non-linear response of the flight-degraded material. +Explicit finite element analysis (FEA) lends itself to nonlinear-elastic stress-strain relation +instead of linear-elastic. Thus, instead of 𝝈 = 𝐄𝜺, the modulus will be defined as a +function of some effective strain quantity, or 𝝈 = 𝐄(𝜺eff) ⋅ 𝜺, even though it is uncertain, +from the available data, whether or not the coating response is completely nonlinear- +elastic, and does not include some damage mechanism. +This nonlinear-elastic model cannot be implemented into a closed form solution or into +an implicit solver; however, for explicit FEA such as is used for LS-DYNA impact +analysis, the modulus can be adjusted at each time step to a higher or lower value as +desired. In order to model the desired S-shape response curve of flight-degraded RCC +coating, a function of strain that replicates the desired response must be found. It is +assumed that the nonlinearities in the material are recoverable (elastic) and that the +modulus is communicative between the 1- and 2- directions (going against the tension- +crack assumption that the two directions do not interact). Sometimes stability can be a +problem for this type of nonlinearity modeling, however, stability was not found to be a +problem with the material constants used for the coating. +The von Mises strain is selected for the effective strain definition as it couples the 3- +dimensional loading but reduces to uniaxial data, so that the desired uniaxial +compressive response can be reproduced. So, +𝜀eff = +√2 +1 + 𝜈 +2 +√(𝜀1 − 𝜀2)2 + (𝜀2 − 𝜀3)2 + (𝜀1 − 𝜀3)2 + 3𝛾12 +where for a 2-D, isotropic shell element case, the z-direction strain is given by: +The function for modulus is implemented as an arbitrary 5th order polynomial: +𝜀3 = +−𝜈 +1 − 𝜈 +(𝜀1 + 𝜀2) +𝐸(𝜀eff) = 𝐴0𝜀eff +5 +1 + ⋯ + 𝐴5𝜀eff +0 + 𝐴1𝜀eff +In the case of as-fabricated material the first coefficient (A0) is simply the modulus E, +and the other coefficients (An > 0) are zero, reducing to a 0th order polynomial, or linear. +To match the degraded stress-strain compression curve, a higher order polynomial is +needed. Six conditions on stress were used (stress and its derivative at beginning, +middle, and end of the curve) to obtain a 5th order polynomial, and then the derivative +of that equation was taken to obtain modulus as a function of strain, yielding a 4th order +polynomial that represents the degraded coating modulus vs. strain curve. +For values of strain which exceed the failure strain observed in the laminate +compression tests, the higher order polynomial will no longer match the test data. +Therefore, after a specified effective-strain, representing failure, the modulus is defined +to be the tangent of the polynomial curve. As a result, the stress/strain response has a +continuous derivative, which aids in avoiding numerical instabilities. The test data +does not clearly define the failure strain of the coating, but in the impact test it appears +that the coating has a higher compressive failure strain in bending than the laminate +failure strain. +The two dominant modes of loading which cause coating loss on the impact side of the +RCC (the front-side) are in-plane compression and transverse shear. The in-plane +compression is measured by the peak out of plane tensile strain, ε3. As there is no direct +loading of a shell element in this direction, ε3 is computed through Poisson’s relation +1−𝑣 (𝜀1 + 𝜀2) . When ε3 is tensile, it implies that the average of ε1 and ε2 is +𝜀3 = −𝑣 +compressive. This failure mode will likely dominate when the RCC undergoes large +bending, putting the front-side coating in high compressive strains. It is expected that a +transverse shear failure mode will dominate when the debris source is very hard or +very fast. By definition, the shell element cannot give a precise account of the +transverse shear throughout the RCC’s thickness. However, the Belytschko-Tsay shell +element formulation in LS-DYNA has a first-order approximation of transverse shear +that is based on the out-of-plane nodal displacements and rotations that should suffice +to give a qualitative evaluation of the transverse shear. By this formulation, the +transverse shear is constant through the entire shell thickness and thus violates surface- +traction conditions. The constitutive model implementation records the peak value of +the tensile out-of-plane strain (ε3) and peak root-mean-sum transverse-shear: √𝜀13 +2 . +2 + 𝜀23 +*MAT_237 +This is Material Type 237. This is a perfectly-matched layer (PML) material with a Biot +linear hysteretic constitutive law, to be used in a wave-absorbing layer adjacent to a Biot +hysteretic material (*MAT_BIOT_HYSTERETIC) in order to simulate wave propagation +in an unbounded medium with material damping. This material is the visco-elastic +counterpart of the elastic PML material (*MAT_PML_ELASTIC). See the Remarks +*MAT_BIOT_HYSTERETIC +sections of +(*MAT_232) for further details. +*MAT_PML_ELASTIC +(*MAT_230) and +Card +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +ZT +F +6 +FD +F +7 +8 +Default +none +none +none +none +0.0 +3.25 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +E +PR +ZT +FD +Mass density. +Young’s modulus. +Poisson’s ratio. +Damping ratio +Dominant excitation frequency in Hz +*MAT_PERT_PIECEWISE_LINEAR_PLASTICITY +This is Material Type 238. It is a duplicate of Material Type 24 (*MAT_PIECEWISE_- +LINEAR_PLASTICITY) modified for use with *PERTURBATION_MATERIAL and +solid elements in an explicit analysis. It should give exactly the same values as the +original material, if used exactly the same. It exists as a separate material type because +of the speed penalty (an approximately 10% increase in the overall execution time) +associated with the use of a material perturbation. +See Material Type 24 (*MAT_PIECEWISE_LINEAR_PLASTICITY) for a description of +the material parameters. All of the documentation for Material Type 24 applies. +Recommend practice is to first create the input deck using Material Type 24. +Additionally, the CMP variable in the *PERTURBATION_MATERIAL must be set to +affect a specific variables in the MAT_238 definition as defined in the following table; +for example, CMP = 5 will perturb the yield stress. +CMP value +Material variable +3 +5 +6 +7 +E +SIGY +ETAN +FAIL +*MAT_COHESIVE_MIXED_MODE_ELASTOPLASTIC_RATE +This is Material Type 240. This model is a rate-dependent, elastic-ideally plastic +cohesive zone model. It includes a tri-linear traction-separation law with a quadratic +yield and damage initiation criterion in mixed-mode loading, while the damage +evolution is governed by a power-law formulation. It can be used only with cohesive +element fomulations; see the variable ELFORM in *SECTION_SOLID and *SECTION_ +SHELL. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +RO +ROFLG +INTFAIL +EMOD +GMOD +THICK +Type +A8 + Card 2 +1 +F +2 +F +3 +Variable +G1C_0 +G1C_INF EDOT_G1 +Type +F + Card 3 +1 +F +2 +F +3 +F +F +4 +T0 +F +4 +5 +T1 +F +5 +F +6 +F +7 +8 +EDOT_T +FG1 +LCG1C +F +6 +F +7 +F +8 +Variable +G2C_0 +G2C_INF EDOT_G2 +S0 +S1 +EDOT_S +FG2 +LCG2C +Type +F +F +F +F +F +F +F +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +ROFLG +Flag for whether density is specified per unit area or volume. +ROFLG = 0 specified density per unit volume (default), and +ROFLG = 1 specifies the density is per unit area for controlling +the mass of cohesive elements with an initial volume of zero. +INTFAIL +*MAT_COHESIVE_MIXED_MODE_ELASTOPLASTIC_RATE +DESCRIPTION +The number of integration points required for the cohesive +element to be deleted. If it is zero, the element will not be deleted +even if it satisfies the failure criterion. The value of INTFAIL may +range from 1 to 4, with 1 the recommended value. +EMOD +The Young’s modulus of the material +GMOD +The shear modulus of the material +THICK +GT.0.0: Cohesive thickness +LE.0.0: Initial thickness is calculated from nodal coordinates +G1C_0 +GT.0.0: Energy release rate GIC in Mode I +LE.0.0: Lower bound value of rate-dependent GIC +G1C_INF +EDOT_G1 +T0 +T1 +Upper bound value of rate-dependent 𝐺𝐼𝐶 (only considered if +G1C_0 < 0) +Equivalent strain rate at yield initiation to describe the rate +dependency of GIC (only considered if G1C_0 < 0) +GT.0.0: Yield stress in Mode I +LT.0.0: Rate-dependency is considered, Parameter T0 +Parameter T1, only considered if T0 < 0: +GT.0.0: Quadratic logarithmic model +LT.0.0: Linear logarithmic model +EDOT_T +Equivalent strain rate at yield initiation to describe the rate +dependency of the yield stress in Mode I (only considered if +T0 < 0) +FG1 +Parameter fG1 to describe the tri-linear shape of the traction- +separation law in Mode I, see remarks. +GT.0.0: FG1 is ratio of fracture energies 𝐺𝐼,𝑃/𝐺𝐼𝐶 +LT.0.0: |FG1| is ratio of displacements (𝛿𝑛2 − 𝛿𝑛1)/(𝛿𝑛𝑓 − 𝛿𝑛1) +LCG1C +Load curve ID which defines fracture energy GIC as a function of +cohesive element thickness. G1C_0 and G1C_INF are ignored in +that case. +Stress +T, S +En, Et +Unloading Path +Gp +Gc +n1, δ +t1 +n2, δ +t2 +nf, δ +tf +n, Δ +Figure M240-1. Trilinear traction separation law +DESCRIPTION +GT.0.0: Energy release rate GIIC in Mode II +LE.0.0: Lower bound value of rate-dependent GIIC + VARIABLE +G2C_0 +G2C_INF +Upper bound value of 𝐺𝐼𝐼𝐶 (only considered if G2C_0 < 0) +EDOT_G2 +Equivalent strain rate at yield initiation to describe the rate +dependency of GIIC (only considered if G2C_0 < 0) +S0 +S1 +GT.0.0: Yield stress in Mode II +LT.0.0: Rate-dependency is considered, Parameter S0 +Parameter S1, only considered if S0 < 0: +GT.0.0: Quadratic logarithmic model is applied +LT.0.0: Linear logarithmic model is applied +EDOT_S +Equivalent strain rate at yield initiation to describe the rate +dependency of the yield stress in Mode II (only considered if +S0 < 0) +FG2 +Parameter fG2 to describe the tri-linear shape of the traction- +separation law in Mode II, see remarks. +GT.0.0: FG2 is ratio of fracture energies 𝐺𝐼𝐼,𝑃/𝐺𝐼𝐼𝐶 +LT.0.0: |FG2| is ratio of displacements (𝛿𝑡2 − 𝛿𝑡1)/(𝛿𝑡𝑓 − 𝛿𝑡1) +Load curve ID which defines fracture energy GIIC as a function of +cohesive element thickness. G2C_0 and G2C_INF are ignored in +that case. +*MAT_240 + VARIABLE +LCG2C +Remarks: +The model is a tri-linear elastic-ideally plastic Cohesive Zone Model, which was +developed by Marzi et al. [2009]. It looks similar to *MAT_185, but considers effects of +plasticity and rate-dependency. Since the entire separation at failure is plastic, no brittle +fracture behavior can be modeled with this material type. +The separations Δ𝑛 in normal (peel) and Δ𝑡 in tangential (shear) direction are calculated +from the element’s separations in the integration points, +and +Δ𝑛 = max (un, 0) +Δ𝑡 = √𝑢𝑡1 +2 , +2 + 𝑢𝑡2 +𝑢𝑛, 𝑢𝑡1 and 𝑢𝑡2 are the separations in normal and in the both tangential directions of the +element coordinate system. The total (mixed-mode) separation Δ𝑚 is determined by +Δ𝑚 = √Δ𝑛 +2 + Δ𝑡 +2. +The initial stiffnesses in both modes are calculated from the elastic Young’s and shear +moduli and are respectively, +𝐸𝑛 = +𝐸𝑡 = +EMOD +THICK +GMOD +THICK +, +where THICK, the element’s thickness, is an input parameter. Unless the input +THICK > 0 it is calculated from the distance between the initial positions of the +element’s corner nodes (Nodes 1-5, 2-6, 3-7 and 4-8, respectively). +While the total energy under the traction-separation law is given by 𝐺𝐶, one further +parameter is needed to describe the exact shape of the tri-linear material model. If the +area (energy) under the constant stress (plateau) region is denoted 𝐺𝑃 , a +parameter 𝑓𝐺 defines the shape of the traction-separation law, +for mode I loading: +0 ≤ 𝑓𝐺1 = +𝐺𝐼,𝑃 +𝐺𝐼𝐶 +< 1 − +𝑇2 +2𝐺𝐼𝐶𝐸𝑛 +< 1 +for mode II loading: +0 ≤ 𝑓𝐺2 = +𝐺𝐼𝐼,𝑃 +𝐺𝐼𝐼𝐶 +< 1 − +𝑆2 +2𝐺𝐼𝐼𝐶𝐸𝑡 +< 1 +As a recommended alternative, the shape of the tri-linear model can be described by the +following displacement ratios (triggered by negative input values for 𝑓𝐺): +for mode I loading: +𝛿𝑛2 − 𝛿𝑛1 +𝛿𝑛𝑓 − 𝛿𝑛1 +0 < ∣𝑓𝐺1∣ = ∣ +∣ < 1 +for mode II loading: +𝛿𝑡2 − 𝛿𝑡1 +𝛿𝑡𝑓 − 𝛿𝑡1 +0 < ∣𝑓𝐺2∣ = ∣ +∣ < 1 +While 𝑓𝐺1 and 𝑓𝐺2 are always constant values, 𝑇, 𝑆, 𝐺𝐼𝐶 and 𝐺𝐼𝐼𝐶 may be chosen as +functions of an equivalent strain rate 𝜀̇𝑒𝑞, which is evaluated by +𝜀̇𝑒𝑞 = +√𝑢̇𝑛 +2 + 𝑢̇𝑡2 +2 + 𝑢̇𝑡1 +THICK +, +where 𝑢̇𝑛, 𝑢̇𝑡1 and 𝑢̇𝑡2 are the velocities corresponding to the separations 𝑢𝑛, 𝑢𝑡1 and 𝑢𝑡2. +For the yield stresses, two rate dependent formulations are implemented: +1. A quadratic logarithmic function: +for mode I if T0 < 0 and T1 > 0: +𝑇(𝜀̇eq) = |T0| + |T1| [max (0, ln +𝜀̇eq +EDOT_ T +)] +for mode II if S0 < 0 and S1 > 0: +𝑆(𝜀̇eq) = |S0| + |S1| [max (0, ln +𝜀̇eq +EDOT_ S +)] +2. A linear logarithmic function: +for mode I if T0 < 0 and T1 < 0: +𝑇(𝜀̇eq) = |T0| + |T1|max (0, ln +𝜀̇eq +EDOT_ T +) +for mode II if S0 < 0 and S1 < 0: +𝜀̇eq +EDOT_ S +𝑆(𝜀̇eq) = |S0| + |S1|max (0, ln +) +Alternatively, T and S can be set to constant values: +for mode I if T0 > 0: +𝑇(𝜀̇eq) = T0 +for mode II if S0 > 0: +𝑆(𝜀̇eq) = SO +The rate-dependency of the fracture energies are given by +if G1C_ 0 < 0: +𝐺𝐼𝐶(𝜀̇eq) = |G1C_ 0| + (G1C_ INF − |G1C_ 0|)exp (− +EDOT_ G1 +𝜀̇eq +) +if G2C_ 0 < 0: +𝐺𝐼𝐼𝐶(𝜀̇eq) = |G2C_ 0| + (G2C_ INF − |G2C_ 0|)exp (− +EDOT_ G2 +𝜀̇eq +) +If positive values are chosen for G1C_0 or G2C_0, no rate-dependency is considered for +this parameter and its value remains constant as specified by the user. +As an alternative, fracture energies GIC and GIIC can be defined as functions of +cohesive element thickness by using load curves LCG1C and LCG2C. In that case, +parameters G1C_0, G1C_INF, G2C_0, and G2C_INF will be ignored and no rate +dependence is considered. +It should be noticed, that the equivalent strain rate 𝜀̇eq is updated until Δ𝑚 > 𝛿𝑚1, then +the model behavior depends on the equivalent strain rate at yield initiation. +Having defined the parameters describing the single modes, the mixed-mode behavior +is formulated by quadratic initiation criteria for both yield stress and damage initiation, +while the damage evolution follows a Power-Law. +Traction +n1 +n2 +nf +Δn +t1 +m1 +tf +t2 +Δt +m2 +mf +Δm +Figure M240-2. Trilinear mixed mode traction-separation law +Due to reasons of readability, the following simplifications are made, +𝑇 = 𝑇(𝜀̇eq), 𝑆 = 𝑆(𝜀̇eq), 𝐺𝐼𝐶 = 𝐺𝐼𝐶(𝜀̇eq) and 𝐺𝐼𝐼𝐶 = 𝐺𝐼𝐼𝐶(𝜀̇eq). +The mixed-mode yield initiation displacement 𝛿𝑚1 is defined as +𝛿𝑚1 = 𝛿𝑛1𝛿𝑡1√ +1 + 𝛽2 +2 + (𝛽𝛿𝑛1)2 +𝛿𝑡1 +, + are the single-mode yield initiation displacements and + is the mixed-mode ratio. Analog to the yield initiation, the damage initiation + and 𝛿𝑡1 = 𝑆 +𝐸𝑡 +where 𝛿𝑛1 = 𝑇 +𝐸𝑛 +𝛽 = +displacement 𝛿𝑚2 is defined: +Δ𝑡 +Δ𝑛 +𝛿𝑚2 = 𝛿𝑛2𝛿𝑡2√ +1 + 𝛽2 +2 + (𝛽𝛿𝑛2)2 +, +𝛿𝑡2 +where +𝛿𝑛2 = 𝛿𝑛1 + +𝛿𝑡2 = 𝛿𝑡1 + +𝑓𝐺1𝐺𝐼𝐶 +𝑓𝐺2𝐺𝐼𝐼𝐶 +. +With 𝛾 = arccos( +⟨𝑢𝑛⟩ +Δ𝑚 +), the ultimate (failure) displacement 𝛿𝑚𝑓 can be written, +𝛿𝑚𝑓 = +𝛿𝑚1(𝛿𝑚1 − 𝛿𝑚2)𝐸𝑛𝐺𝐼𝐼𝐶cos2𝛾 + 𝐺𝐼𝐶(2𝐺𝐼𝐼𝐶 + 𝛿𝑚1(𝛿𝑚1 − 𝛿𝑚2)𝐸𝑡sin2𝛾) +𝛿𝑚1(𝐸𝑛𝐺𝐼𝐼𝐶cos2𝛾 + 𝐸𝑡𝐺𝐼𝐶sin2𝛾) +. +This formulation describes a power-law damage evolution with an exponent 𝜂 = 1.0 +. +After the shape of the mixed-mode traction-separation law has been determined by +𝛿𝑚1, 𝛿𝑚2 and 𝛿𝑚𝑓 , the plastic separation in each element direction, 𝑢𝑛,𝑃, 𝑢𝑡1,𝑃 and 𝑢𝑡2,𝑃 can +be calculated. The plastic separation in peel direction is given by +𝑢𝑛,𝑃 = max(𝑢𝑛,𝑃,Δ𝑡−1, 𝑢𝑛 − 𝛿𝑚1cos (𝛾), 0). +In shear direction, a shear yield separation 𝛿𝑡,𝑦, +𝛿𝑡,𝑦 = √(𝑢𝑡1 − 𝑢𝑡1,𝑃,Δ𝑡−1)2 + (𝑢𝑡2 − 𝑢𝑡2,𝑃,Δ𝑡−1)2, +is defined. If 𝛿𝑡,𝑦 > 𝛿𝑚1sin𝛾, the plastic shear separations in the element coordinate +system are updated, +𝑢𝑡1,𝑃 = 𝑢𝑡1,𝑃,Δ𝑡−1 + 𝑢𝑡1 − 𝑢𝑡1,Δ𝑡−1 +𝑢𝑡2,𝑃 = 𝑢𝑡2,𝑃,Δ𝑡−1 + 𝑢𝑡2 − 𝑢𝑡2,Δ𝑡−1. +In the formulas above, Δ𝑡 − 1 indicates the individual value from the last time +increment. In case Δ𝑚 > 𝛿𝑚2, the damage initiation criterion is satisfied and a damage +variable D increases monotonically, +𝐷 = max ( +Δ𝑚 − 𝛿𝑚2 +𝛿𝑚𝑓 − 𝛿𝑚2 +, 𝐷Δ𝑡−1, 0). +When Δ𝑚 > 𝛿𝑚𝑓 , complete damage (𝐷 = 1) is reached and the element fails in the +corresponding integration point. +Finally, the peel and the shear stresses in element directions are calculated, +𝜎𝑡1 = 𝐸𝑡(1 − 𝐷)(𝑢𝑡1 − 𝑢𝑡1,𝑃) +𝜎𝑡2 = 𝐸𝑡(1 − 𝐷)(𝑢𝑡2 − 𝑢𝑡2𝑃). +In peel direction, no damage under pressure loads is considered if 𝑢𝑛 − 𝑢𝑛,𝑃 > 0 +otherwise, +Reference: +𝜎𝑛 = 𝐸𝑛(𝑢𝑛 − 𝑢𝑛,𝑃) +𝜎𝑛 = 𝐸𝑛(1 − 𝐷)(𝑢𝑛 − 𝑢𝑛,𝑃) +S. Marzi, O. Hesebeck, M. Brede and F. Kleiner (2009), A Rate-Dependent, Elasto- +Plastic Cohesive Zone Mixed-Mode Model for Crash Analysis of Adhesively Bonded +Joints, In Proceeding: 7th European LS-DYNA Conference, Salzburg +*MAT_JOHNSON_HOLMQUIST_JH1 +This is Material Type 241. This Johnson-Holmquist Plasticity Damage Model is useful +for modeling ceramics, glass and other brittle materials. This version corresponds to the +original version of the model, JH1, and Material Type 110 corresponds to JH2, the +updated model. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +Variable +EPSI +Type +F + Card 3 +1 +2 +RO +F +2 +T +F +2 +Variable +EPFMIN +EPFMAX +Type +F +F + VARIABLE +MID +8 +C +F +8 +8 +3 +G +F +3 +4 +P1 +F +4 +5 +S1 +F +5 +6 +P2 +F +6 +7 +S2 +F +7 +ALPHA +SFMAX +BETA +DP1 +F +7 +F +F +F +F +3 +K1 +F +4 +K2 +F +5 +K3 +F +6 +FS +F +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Density. +G +P1 +S1 +P2 +S2 +Shear modulus. +Pressure point 1 for intact material. +Effective stress at P1. +Pressure point 2 for intact material. +Effective stress at P2. +Intact material +strength (D < 0) +(P1, S1) +(P2, S2) +(P3, S3) +. +ε*>1 +. +ε*=1 +. +ε*>1 +. +ε*=1 +Fractured material +strength (D ≥ 0) +ALPHA +(T, 0) +Pressure +Figure M241-1. Strength: equivalent stress versus pressure. + VARIABLE +DESCRIPTION +C +EPSI +T +Strain rate sensitivity factor. +Quasi-static threshold strain rate. See *MAT_015. +Maximum tensile pressure strength. This value is positive in +tension. +ALPHA +Initial slope of the fractured material strength curve. See +Figure M241-1. +SFMAX +Maximum strength of the fractured material. +BETA +DP1 +Fraction of elastic energy loss converted to hydrostatic energy +(affects bulking pressure (history variable 1) that accompanies +damage). +Maximum compressive pressure strength. This value is positive +in compression. +EPFMIN +Plastic strain for fracture at tensile pressure 𝑇. See Figure M241-2. +EPFMAX +Plastic strain for fracture at compressive pressure DP1. See +Figure M241-1. +K1 +K2 +First pressure coefficient (equivalent to the bulk modulus). +Second pressure coefficient. +) +fp +( +(DP1, EPFMAX) +(T, EPFMIN) +Pressure +Figure M241-2. Fracture strain versus pressure. + VARIABLE +DESCRIPTION +K3 +FS +Third pressure coefficient. +Element deletion criteria. +LT.0: delete if P < FS (tensile failure). +EQ.0: no element deletion (default). +GT.0: delete element if the 𝜀̅𝑝> FS. +Remarks: +The equivalent stress for both intact and fractured ceramic-type materials is given by +𝜎𝑦 = (1 + 𝑐 ln 𝜀̇∗)𝜎(𝑃) +where 𝜎(𝑃) is evaluated according to Figure M241-1. +𝑝 (𝑃) +𝐷 = ∑ Δ𝜀𝑝/𝜀𝑓 +represents the accumulated damage (history variable 2) based upon the increase in +plastic strain per computational cycle and the plastic strain to fracture is evaluated +according to Figure M241-2. +In undamaged material, the hydrostatic pressure is given by +in compression and by +𝑃 = 𝑘1𝜇 + 𝑘2𝜇2 + 𝑘3𝜇3 + 𝛥𝑃 +𝑃 = 𝑘1𝜇 + 𝛥𝑃 +in tension where 𝜇 = 𝜌 𝜌0 − 1 +. A fraction, between 0 and 1, of the elastic energy loss, 𝛽, +is converted into hydrostatic potentiall energy (pressure). The pressure increment, 𝛥𝑃, +associated with the increment in the hydrostatic potential energy is calculated at +⁄ +𝑓 are the intact and failed yield stresses respectively. This +fracture, where 𝜎𝑦 and 𝜎𝑦 +pressure increment is applied both in compression and tension, which is not true for +JH2 where the increment is added only in compression. +𝛥𝑃 = −𝑘1𝜇𝑓 + √(𝑘1𝜇𝑓 ) ++ 2𝛽𝑘1𝛥𝑈 +𝛥𝑈 = +𝜎𝑦 − 𝜎𝑦 +6𝐺 +*MAT_KINEMATIC_HARDENING_BARLAT2000 +This is Material Type 242. This model combines Yoshida non-linear kinematic +hardening rule (*MAT_125) with the 8-parameter material model of Barlat and Lian +(2003) (*MAT_133) to model metal sheets under cyclic plasticity loading and with +anisotropy in plane stress condition. Also see manual pages in *MAT_226. + Card 1 +1 +Variable +MID +Type +I +2 +RO +F +3 +E +F +4 +PR +F +5 +6 +8 +7 +M +F +Default +none +0.0 +0.0 +0.0 +none + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ALPHA1 +ALPHA2 +ALPHA3 +ALPHA4 +ALPHA5 +ALPHA6 +ALPHA7 +ALPHA8 +Type +F +F +F +F +F +F +F +I +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +none + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +Default +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +Default + Card 5 +Variable +1 +CB +Type +F +2 +Y +F +3 +C +F +4 +K +F +5 +RSAT +F +6 +SB +F +7 +H +F +8 +Default +none +none +none +none +none +none +none + Card 6 +1 +2 +3 +Variable +AOPT +Type +I +IOPT +I +4 +C1 +F +5 +C2 +F +Default +none +none +0.0 +0.0 +6 +7 +8 + Card 7 +Variable +1 +XP +Type +F +2 +YP +F +3 +ZP +F +4 +A1 +F +5 +A2 +F +6 +A3 +F +7 +8 +Default +none +none +none +none +none +none +Card 8 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +Default +none +none +none +none +none +none + VARIABLE +DESCRIPTION +MID +RO +E +PR +M +ALPHA1 +ALPHA2 +ALPHA3 +ALPHA4 +ALPHA5 +ALPHA6 +ALPHA7 +ALPHA8 +CB +Y +SC +K +RSAT +SB +Material identification. A unique number must be specified. +Mass density. +Young’s modulus, E. +Poisson’s ratio, ν. +Flow potential exponent. For face centered cubic (FCC) materials +m = 8 is recommended and for body centered cubic (BCC) +materials m = 6 may be used. +α1, material constant in Barlat’s yield equation. +α2, material constant in Barlat’s yield equation. +α3, material constant in Barlat’s yield equation. +α4, material constant in Barlat’s yield equation. +α5, material constant in Barlat’s yield equation. +α6, material constant in Barlat’s yield equation. +α7, material constant in Barlat’s yield equation. +α8, material constant in Barlat’s yield equation. +The uppercase B defined in the Yoshida’s equations. +Anisotropic parameter +stagnation, defined in the Yoshida’s equations. +associated with work-hardening +The lowercase c defined in the Yoshida’s equations. +Hardening parameter as defined in the Yoshida’s equations. +Hardening parameter as defined in the Yoshida’s equations. +The lowercase b as defined in the Yoshida’s equations. +H +AOPT +*MAT_KINEMATIC_HARDENING_BARLAT2000 +DESCRIPTION +Anisotropic parameter +stagnation, defined in the following Yoshida’s equations. +associated with work-hardening +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available with the R3 release +of Version 971 and later. +IOPT +Kinematic hardening rule flag: +EQ.0: Original Yoshida formulation. +EQ.1: Modified formulation. Define C1, C2 below. +C1, C2 +Constants used to modify R: +𝑅 = RSAT × [(𝐶1 + 𝜀̅𝑝)𝑐2 − 𝐶1 +𝑐2] +Coordinates of point p for AOPT = 1. +Components of vector a for AOPT = 2. +Components of vector v for AOPT = 3. +Components of vector d for AOPT = 2. +XP, YP, ZP +A1, A2, A3 +V1, V2, V3 +D1, D2, D3 +Remarks: +1. A total of eight parameters (α1 to α8) are needed to describe the yield surface. +The parameters can be determined with tensile tests in three directions and an +equal biaxial tension test. For detailed theoretical background and material +parameters of some typical FCC materials, please see remarks in *MAT_133 and +Barlat’s 2003 paper. +2. NUMISHEET 2005 provided a complete set of the parameters of AL5182-O for +Benchmark #2, the cross member, as below (flow potential exponent M = 8): +α1 +0.94 +α2 +1.08 +α3 +0.97 +α4 +1.0 +α5 +1.0 +α6 +1.02 +α7 +1.03 +α8 +1.11 +3. For a more detailed description on the Yoshida model and parameters, please +see Remarks in *MAT_226 and *MAT_125. +4. For information on variable AOPT please see remarks in *MAT_226. +5. To improve convergence, it is recommended that *CONTROL_IMPLICIT_- +FORMING type ‘1’ be used when conducting springback simulation. +6. This material model is available in LS-DYNA R5 Revision 58432 or later +releases. +*MAT_HILL_90 +This is Material Type 243. This model was developed by Hill [1990] for modeling sheets +with anisotropic materials under plane stress conditions. This material allows the use +of the Lankford parameters for the definition of the anisotropy. All features of this +model are the same as in *MAT_036, only the yield condition and associated flow rules +are replaced by the Hill90 equations. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +Variable +Type +1 +M +F +2 +RO +F +2 +3 +E +F +3 +4 +PR +F +4 +5 +HR +F +5 +R00 / AH R45 / BH R90 / CH +LCID +F +F +F +I +6 +P1 +F +6 +E0 +F +7 +P2 +F +7 +SPI +F +8 +ITER +F +8 +P3 +F +Hardening Card. Additional Card for M < 0. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CRC1 +CRA1 +CRC2 +CRA2 +CRC3 +CRA3 +CRC4 +CRA4 +Type +F + Card 4 +1 +Variable +AOPT +Type +F +F +2 +C +F +F +5 +F +3 +P +F +F +4 +VLCID +I +F +6 +FLAG +F +F +7 +F +1 +2 +3 +Variable +Type + Card 6 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +This card is optional. +4 +A1 +F +4 +D1 +F +5 +A2 +F +5 +D2 +F +6 +A3 +F +6 +D3 +F +*MAT_243 +7 +8 +7 +8 +BETA +F + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +USRFAIL +Type +F + VARIABLE +DESCRIPTION +MID +RO +E +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus, E +GT.0.0: Constant value, +LT.0.0: Load curve ID = (-E) which defines Young’s Modulus +as a function of plastic strain. See Remark 1. +PR +Poisson’s ratio, ν +*MAT_HILL_90 +DESCRIPTION +HR +Hardening rule: +EQ.1.0: linear (default), +EQ.2.0: exponential (Swift) +EQ.3.0: load curve or table with strain rate effects +EQ.4.0: exponential (Voce) +EQ.5.0: exponential (Gosh) +EQ.6.0: exponential (Hocket-Sherby) +EQ.7.0: load curves in three directions +EQ.8.0: table with temperature dependence +EQ.9.0: 3d table with temperature and strain rate dependence +P1 +Material parameter: +HR.EQ.1.0: Tangent modulus, +HR.EQ.2.0: k, strength coefficient +hardening +for Swift exponential +HR.EQ.4.0: a, coefficient for Voce exponential hardening +HR.EQ.5.0: k, strength coefficient +hardening +for Gosh exponential +HR.EQ.6.0: a, coefficient +for Hocket-Sherby exponential +hardening +HR.EQ.7.0: load curve ID for hardening in 45 degree direction. +See Remark 2. +P2 +Material parameter: +HR.EQ.1.0: Yield stress +HR.EQ.2.0: n, exponent for Swift exponential hardening +HR.EQ.4.0: c, coefficient for Voce exponential hardening +HR.EQ.5.0: n, exponent for Gosh exponential hardening +HR.EQ.6.0: c, coefficient +for Hocket-Sherby exponential +hardening +HR.EQ.7.0: load curve ID for hardening in 90 degree direction. +See Remark 2. +DESCRIPTION +ITER +Iteration flag for speed: +ITER.EQ.0.0: fully iterative +ITER.EQ.1.0: fixed at three iterations +*MAT_243 +M +CRCn +CRAn +R00 +Generally, ITER = 0 is recommended. However, ITER = 1 is +somewhat faster and may give acceptable results in most +problems. +m, exponent in Hill’s yield surface, absolute value is used if +negative. Typically, m ranges between 1 and 2 for low-r +materials, such as aluminum (AA6111: m≈1.5), and is greater than +2 for high r-values, as in steel (DP600: m≈4). +Chaboche-Rousselier hardening parameters, see remarks. +Chaboche-Rousselier hardening parameters, see remarks. +R00, Lankford parameter in 0 degree direction +GT.0.0: Constant value, +LT.0.0: Load curve or Table ID = (-R00) which defines R value +as a function of plastic strain (Curve) or as a function of +temperature and plastic strain (Table). See Remark 3. +R45 +R45, Lankford parameter in 45 degree direction +GT.0.0: Constant value, +LT.0.0: Load curve or Table ID = (-R45) which defines R value +as a function of plastic strain (Curve) or as a function of +temperature and plastic strain (Table). See Remarks 2 +and 3. +R90 +R90, Lankford parameter in 90 degree direction +GT.0.0: Constant value, +LT.0.0: Load curve or Table ID = (-R90) which defines R value +as a function of plastic strain (Curve) or as a function of +temperature and plastic strain (Table). See Remarks 2 +and 3. +AH +BH +a, Hill90 parameter, which is read instead of R00 if FLAG = 1. +b, Hill90 parameter, which is read instead of R45 if FLAG = 1. +CH +LCID +*MAT_HILL_90 +DESCRIPTION +c, Hill90 parameter, which is read instead of R90 if FLAG = 1. +Load curve/table ID for hardening in the 0 degree direction. See +Remark 1. +E0 +Material parameter +HR.EQ.2.0: 𝜀0 for determining initial yield stress for Swift +exponential hardening. (Default = 0.0) +HR.EQ.4.0: b, coefficient for Voce exponential hardening +HR.EQ.5.0: 𝜀0 for determining initial yield stress for Gosh +exponential hardening. (Default = 0.0) +HR.EQ.6.0: b, coefficient +for Hocket-Sherby exponential +hardening +SPI +if 𝜀0 is zero above and HR = 2.0. (Default = 0.0) +⁄ +(𝑛−1) +EQ.0.0: 𝜀0 = +⎜⎜⎜⎛𝐸 +𝑘⁄ +⎝ +⎟⎟⎟⎞ +⎠ +LE.0.02: 𝜀0 = SPI +GT.0.02: 𝜀0 = +1 𝑛⁄ +⎜⎜⎜⎛SPI +⁄ +⎝ +⎟⎟⎟⎞ +⎠ +If HR = 5.0 the strain at plastic yield is determined by an iterative +procedure based on the same principles as for HR.EQ.2.0. +P3 +Material parameter: +HR.EQ.5.0: p, parameter for Gosh exponential hardening +HR.EQ.6.0: n, exponent +for Hocket-Sherby exponential +hardening +AOPT +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the shell ele- +ment normal by the angle BETA. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +C +P +VLCID +FLAG +*MAT_243 +DESCRIPTION +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available with the R3 release +of Version 971 and later. +C in Cowper-Symonds strain rate model +p in Cowper-Symonds strain rate model, p = 0.0 for no strain rate +effects +Volume correction curve ID defining the relative volume change +(change in volume relative to the initial volume) as a function of +the effective plastic strain. This is only used when nonzero. See +Remark 1. +Flag for interpretation of parameters. If FLAG = 1, parameters +AH, BH, and CH are read instead of R00, R45, and R90. See +Remark 4. +XP, YP, ZP +Coordinates of point p for AOPT = 1. +A1, A2, A3 +Components of vector a for AOPT = 2. +V1, V2, V3 +Components of vector v for AOPT = 3. +D1, D2, D3 +Components of vector d for AOPT = 2. +BETA +Material angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA. +USRFAIL +User defined failure flag +USRFAIL.EQ.0: no user subroutine is called +USRFAIL.EQ.1: user subroutine matusr_24 in dyn21.f is called +*MAT_HILL_90 +1. The effective plastic strain used in this model is defined to be plastic work +equivalent. A consequence of this is that for parameters defined as functions of +effective plastic strain, the rolling (00) direction should be used as reference +direction. For instance, the hardening curve for HR = 3 is the stress as function +of strain for uniaxial tension in the rolling direction, VLCID curve should give +the relative volume change as function of strain for uniaxial tension in the roll- +ing direction and load curve given by -E should give the Young’s modulus as +function of strain for uniaxial tension in the rolling direction. Optionally the +curve can be substituted for a table defining hardening as function of plastic +strain rate (HR = 3) or temperature (HR = 8). +2. Exceptions from the rule above are curves defined as functions of plastic strain +in the 45 and 90 directions, i.e., P1 and P2 for HR = 7 and negative R45 or R90. +The hardening curves are here defined as measured stress as function of meas- +ured plastic strain for uniaxial tension in the direction of interest, i.e., as deter- +mined from experimental testing using a standard procedure. Moreover, the +curves defining the R values are as function of the measured plastic strain for +uniaxial tension in the direction of interest. These curves are transformed in- +ternally to be used with the effective stress and strain properties in the actual +model. The effective plastic strain does not coincide with the plastic strain +components in other directions than the rolling direction and may be somewhat +confusing to the user. Therefore the von Mises work equivalent plastic strain is +output as history variable #2 if HR = 7 or if any of the R-values is defined as +function of the plastic strain. +3. The R-values in curves are defined as the ratio of instantaneous width change +to instantaneous thickness change. That is, assume that the width W and thick- +ness T are measured as function of strain. Then the corresponding R-value is +given by: +𝑅 = +𝑑𝑊 +𝑑𝜀 +𝑑𝑇 +𝑑𝜀 +/𝑊 +/𝑇 +4. The anisotropic yield criterion Φ for plane stress is defined as: +Φ = 𝐾1 +𝑚 + 𝐾3𝐾2 +(𝑚/2)−1 + 𝑐𝑚𝐾4 +𝑚/2 = (1 + 𝑐𝑚 − 2𝑎 + 𝑏)𝜎𝑌 +𝑚 +where 𝜎𝑌 is the yield stress and Ki = 1,4 are given by: +𝐾1 = ∣𝜎𝑥 + 𝜎𝑦∣ +𝐾2 = ∣𝜎𝑥 +2 + 𝜎𝑦 +2 ∣ +2 + 2𝜎𝑥𝑦 +𝐾3 = −2𝑎(𝜎𝑥 +2 − 𝜎𝑦 +2) + 𝑏(𝜎𝑥 − 𝜎𝑦) +𝐾4 = ∣(𝜎𝑥 − 𝜎𝑦) +2 ∣ ++ 4𝜎𝑥𝑦 +If FLAG = 0, the anisotropic material constants a, b, and c are obtained through +R00, R45, and R90 using these 3 equations: +1 + 2𝑅00 = +𝑐𝑚 − 𝑎 + {(𝑚 + 2)/2𝑚}𝑏 +1 − 𝑎 + {(𝑚 − 2)/2𝑚}𝑏 +1 + 2𝑅45 = 𝑐𝑚 +1 + 2𝑅90 = +𝑐𝑚 + 𝑎 + {(𝑚 + 2)/2𝑚}𝑏 +1 + 𝑎 + {(𝑚 − 2)/2𝑚}𝑏 +If FLAG = 1, material parameters a (AH), b (BH), and c (CH) are used directly. +For material parameters a, b, c, and m, the following condition has to be ful- +filled, otherwise an error termination occurs: +1 + 𝑐𝑚 − 2𝑎 + 𝑏 > 0 +Two even more strict conditions should ensure convexity of the yield surface +according to Hill (1990). A warning message will be dumped if at least one of +them is violated: +𝑏 > −2 +(𝑚 +)−1 +𝑐𝑚 +𝑏 > 𝑎2 − 𝑐𝑚 +The yield strength of the material can be expressed in terms of k and n: +𝜎𝑌 = 𝑘𝜀𝑛 = 𝑘(𝜀𝑦𝑝 + 𝜀̅𝑝) +where 𝜀𝑦𝑝 is the elastic strain to yield and 𝜀̅𝑝 is the effective plastic strain (loga- +rithmic). If SIGY is set to zero, the strain to yield if found by solving for the +intersection of the linearly elastic loading equation with the strain hardening +equation: +which gives the elastic strain at yield as: +𝜎 = 𝐸𝜀 +𝜎 = 𝑘𝜀𝑛 +𝜀𝑦𝑝 = ( +[ 1 +] +𝑛−1 +) +If SIGY yield is nonzero and greater than 0.02 then: +𝜀𝑦𝑝 = ( +𝜎𝑌 +[1 +𝑛] +) +The other available hardening models include the Voce equation given by +𝜎Y(𝜀𝑝) = 𝑎 − 𝑏𝑒−𝑐𝜀𝑝, +the Gosh equation given by +𝜎Y(𝜀𝑝) = 𝑘(𝜀0 + 𝜀𝑝)𝑛 − 𝑝, +and finally the Hocket-Sherby equation given by +𝜎Y(𝜀𝑝) = 𝑎 − 𝑏𝑒−𝑐𝜀𝑝 +. +For the Gosh hardening law, the interpretation of the variable SPI is the same, +i.e., if set to zero the strain at yield is determined implicitly from the intersec- +tion of the strain hardening equation with the linear elastic equation. +To include strain rate effects in the model we multiply the yield stress by a +factor depending on the effective plastic strain rate. We use the Cowper- +Symonds’ model, hence the yield stress can be written +𝜎Y(𝜀𝑝, 𝜀̇𝑝) = 𝜎Y +⎡1 + ( +⎢ +⎣ +𝑠 denotes the static yield stress, 𝐶 and 𝑝 are material parameters, 𝜀̇𝑝 is +𝑠 (𝜀𝑝) +⎤ +⎥ +⎦ +) +1/𝑝 +𝜀̇𝑝 +where 𝜎Y +the effective plastic strain rate. +5. A kinematic hardening model is implemented following the works of Chaboche +and Roussilier. A back stress α is introduced such that the effective stress is +computed as +𝜎eff = 𝜎eff(𝜎11 − 2𝛼11 − 𝛼22, 𝜎22 − 2𝛼22 − 𝛼11, 𝜎12 − 𝛼12) +The back stress is the sum of up to four terms according to +𝛼𝑖𝑗 = ∑ 𝛼𝑖𝑗 +𝑘=1 +and the evolution of each back stress component is as follows +𝛿𝛼𝑖𝑗 +𝑘 = 𝐶𝑘 (𝑎𝑘 +𝑠𝑖𝑗 +𝜎eff +− 𝛼𝑖𝑗 +𝑘 ) 𝛿𝜀𝑝 +where 𝐶𝑘 and 𝑎𝑘 are material parameters,𝑠𝑖𝑗 is the deviatoric stress tensor, 𝜎eff is +the effective stress and 𝜀𝑝 is the effective plastic strain. +*MAT_244 +This material model is developed for both shell and solid models. It is mainly suited for +hot stamping processes where phase transformations are crucial. It has five phases and +it is assumed that the blank is fully austenitized before cooling. The basic constitutive +model is based on the work done by P. Akerstrom [2, 7]. +Automatic switching between cooling and heating of the blank is under development. +To activate the heating algorithm, set HEAT = 1 or 2 and add the appropriate input +Cards. See the description of the HEAT parameter below. HEAT = 0 as is the default +activates only the cooling algorithm and no extra cards need to be read in. Also note +that for HEAT = 0 you must check that the initial temperature of this material is above +the start temperature for the ferrite transformation. The transformation temperatures +are echoed in the messag and in the d3hsp file. +If HEAT > 0 the temperature that instantaneous transform all ferrite back to austenite is +also echoed in the messag file. If you want to heat up to 100% austenite you must let +the specimen’s temperature exceed that temperature. +Features Added in 2014: +1. Young’s modulus and Poisson ratio can now be given as temperature +dependent load curves or by a table definition with a load curve for each phase. +See Remark 8. +2. Latent heat can now be given for each phase. See Remark 9. +3. Thermal expansion can now be given for each phase Remark 10. +4. Advanced reaction kinetic modifications include the ability to tailor the start +temperatures and the activation energies. The martensite start temperature can +be dependent on the plastic strain and triaxiality, and the activation energies +can be scaled with the plastic strain as well. +5. Hardness calculation improved when tempering is active. Improvements are +achieved in the bainite and martensite phases (experimental). See Remark 11. +NOTE: For this material “weight%” means +“ppm × 10-4”. +1 +Variable +MID +Type +I +2 +RO +F +3 +E +F +4 +PR +F +*MAT_UHS_STEEL +5 +6 +7 +8 +TUNIT +CRSH +PHASE +HEAT +Defaults +none +none +none +none +3600 + Card 2 +1 +2 +3 +4 +5 +F +I +0 +6 +I +0 +7 +Variable +LCY1 +LCY2 +LCY3 +LCY4 +LCY5 +KFER +KPER +Type +I +I +I +I +I +F +F +I +0 +8 +B +F +Defaults +none +none +none +none +none +0.0 +0.0 +0.0 + Card 3 +Variable +Type +1 +C +F +2 +Co +F +3 +Mo +F +4 +Cr +F +5 +Ni +F +6 +Mn +F +7 +Si +F +8 +V +F +Defaults +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 4 +Variable +Type +1 +W +F +2 +Cu +F +3 +P +F +4 +Al +F +5 +As +F +6 +Ti +F +Defaults +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +7 +8 +CWM +LCTRE +I +0 +I +none +Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +THEXP1 +THEXP5 +LCTH1 +LCTH5 +TREF +LAT1 +LAT5 +TABTH +Type +F +F +I +I +F +F +F +I +Defaults +0.0 +0.0 +none +none +273.15 +0.0 +0.0 +none + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +QR2 +QR3 +QR4 +ALPHA +GRAIN +TOFFE +TOFPE +TOFBA +Type +F +F +F +F +F +F +F +F +Defaults +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 7 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PLMEM2 PLMEM3 PLMEM4 PLMEM5 +STRC +STRP +REACT +TEMPER +Type +I +F +F +F +F +F +Defaults +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +I +0 +I +0 +Heat Card 1. Additional Card for HEAT = 1. + Card 8 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +AUST +FERR +PEAR +BAIN +MART +GRK +GRQR +TAU1 +Type +F +F +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +2.08E+8 +Heat Card 2. Additional Card for HEAT =1. + Card 9 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +GRA +GRB +EXPA +EXPB +GRCC +GRCM +HEATN +TAU2 +Type +F +F +F +F +F +F +F +F +Default +3.11 +7520. +1.0 +1.0 +none +none +1.0 +4.806 +Reaction Card. Addition card for REACT = 1. + Card 10 +Variable +1 +FS +Type +F +2 +PS +F +3 +BS +F +4 +5 +6 +7 +8 +MS +MSIG +LCEPS23 +LCEPS4 +LCEPS5 +F +F +I +I +I +Default +0.0 +0.0 +0.0 +0.0 +none +none +none +none +Tempering Card. Additional card for TEMPR = 1. + Card 11 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCH4 +LCH5 +DTCRIT +TSAMP +Type +Default +I +0 +I +0 +F +F +0.0 +0.0 +Computational Welding Mechanics Card. Additional card for CWM = 1. + Card 11 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TASTART TAEND TLSTART +TLEND +EGHOST +PGHOST AGHOST +Type +F +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +VARIABLE +DESCRIPTION +BASELINE VALUE +MID +RO +E +Material ID, a unique number has to be +chosen. +Material density +Youngs’ modulus: +GT.0.0: constant value is used +LT.0.0: LCID or TABID. Temperature +dependent Youngs’ modulus +given by load curve ID = -E or +a Table ID = -E. When using a +table to describe the Youngs +for +modulus see Remark 8 +more information. +7830 Kg/m3 +100 GPa [1] +PR +Poisson’s ratio: +0.30 [1] +GT.0.0: constant value +LT.0.0: LCID or TABID: Temperature +dependent Poisson ratio given +by load curve or table ID = -PR. +The table input is described in +Remark 8. +Number of time units per hour. Default +is seconds, that is 3600 time units per + It is used only for hardness +hour. +calculations. +TUNIT +3600. +CRSH +*MAT_UHS_STEEL +DESCRIPTION +BASELINE VALUE +Switch to use a simple and fast material +model but with the actual phases active. +EQ.0: The original model where phase +transitions are active and trip is +used. +EQ.1: A simpler and faster version. +This option +is mainly when +transferring the quenched blank +into a crash analysis where all +properties from the cooling are +maintained. This option must be +*INTERFACE_- +used with a +SPRINGBACK keyword +and +should be used after a quenching +analysis. +EQ.2: Same as 0 but trip effect is not +used. +0 +0 +PHASE +Switch to include or exclude middle +phases from the simulation. +EQ.0: All phases active (default) +EQ.1: pearlite and bainite excluded +EQ.2: bainite excluded +EQ.3: ferrite and pearlite excluded +EQ.4: ferrite and bainite excluded +EQ.5: exclude middle phases +(only austenite → martensite) +VARIABLE +DESCRIPTION +BASELINE VALUE +HEAT +Switch to activate the heating algorithms +EQ.0: Heating is not activated. That +means that no transformation to +Austenite is possible. +EQ.1: Heating is activated: +That +means that only transformation +to Austenite is possible. +EQ.2: Automatic switching between +cooling and heating. LS-DYNA +checks the temperature gradient +and calls the appropriate algo- +rithms. For example, this can be +used to simulate the heat affect- +ed zone during welding. +LT.0: Switch between cooling and +heating is defined by a time de- +pendent +id + The ordinate +ABS(HEAT). +should be 1.0 when heating is +applied and 0.0 if cooling is pref- +erable. +load curve with +LCY1 +Load curve or Table ID for austenite +hardening. +[5] +IF LCID +input yield stress versus effective +plastic strain. +IF TABID.GT.0: +2D table. Input temperatures as table +values and hardening curves as +targets for those temperatures +IF TABID.LT.0: +3D table. Input temperatures as main +table values and strain rates as values +for the sub tables, and hardening +curves as targets for those strain rates. +VARIABLE +DESCRIPTION +BASELINE VALUE +LCY2 +LCY3 +LCY4 +LCY5 +KFERR +KPEAR +B +C +Co +Mo +Cr +Ni +Mn +Si +V +W +Cu +P +Al +As +Ti +Load curve ID for ferrite hardening +(stress versus eff. pl. str.) +Load curve or Table ID for pearlite. See +LCY1 for description. +Load curve or Table ID for bainite. See +LCY1 for description. +Load curve or Table ID for martensite. +See LCY1 for description. +Correction factor for boron in the ferrite +reaction. +Correction factor for boron in the pearlite +reaction. +Boron [weight %] +Carbon [weight %] +Cobolt [weight %] +Molybdenum [weight %] +Chromium [weight %] +Nickel [weight %] +Manganese [weight %] +Silicon [weight %] +Vanadium [weight %] +Tungsten [weight %] +copper [weight %] +Phosphorous [weight %] +Aluminium [weight %] +Arsenic [weight %] +Titanium [weight %] +1.9 × 105 [2] +3.1 × 103 [2] +0.003 [2, 4] +0.23 [2, 4] +0.0 [2, 4] +0.0 [2, 4] +0.21 [2, 4] +0.0 [2, 4] +1.25 [2, 4] +0.29 [2, 4] +0.0 [2, 4] +0.0 +0.0 +0.013 +0.0 +0.0 +0.0 +VARIABLE +CWM +LCTRE +THEXP1 +THEXP5 +LCTH1 +LCTH5 +TREF +LAT1 +DESCRIPTION +BASELINE VALUE +for +Flag +computational welding +mechanics input. One additional input +card is read. +EQ.1.0: Active +EQ.0.0: Inactive +Load curve for transformation induced +for more +strains. +information. + See Remark 13 +Coefficient of +austenite +Coefficient of +martensite +thermal expansion +in +25.1 × 10−6 1/K [7] +thermal expansion +in +11.1 × 10−6 1/K [7] +0 +0 +293.15 +590 × 106 J/m3 [2] +the +Load curve +coefficient for austenite: +for +thermal expansion +LT.0.0: curve ID = -LA and TREF is used as +reference temperature +GT.0.0: curve ID = LA +Load curve +coefficient for martensite: +the +for +thermal expansion +LT.0.0: curve ID = -LA and TREF is used as +reference temperature +GT.0.0: curve ID = LA +temperature +thermal +Reference +expansion. Used if and only if LA.LT.0.0 +or/and LM.LT.0.0 +for +Latent heat for the decomposition of +austenite into ferrite, pearlite and bainite. +GT.0.0: Constant value +LT.0.0: Curve ID or Table ID. See +infor- +for more +Remark 9 +mation. +LAT5 +TABTH +QR2 +QR3 +QR4 +ALPHA +GRAIN +TOFFE +2-1220 (EOS) +DESCRIPTION +Latent heat for the decomposition of +austenite into martensite. +GT.0.0: Constant value +LT.0.0: Curve ID: Note that LAT 5 is +ignored if a Table ID is used in +LAT1. +for +thermal expansion +Table definition +coefficient. With this option active THEXP1, +THEXP2, LCTH1 and LCTH5 are ignored. See +Remark 10. +GT.0: A table for instantaneous thermal +expansion (TREF is ignored). +LT.0: A table with thermal expansion with +reference to TREF. +energy divided by +Activation +the +universal gas constant for the diffusion +reaction of the austenite-ferrite reaction: +Q2/R. R = 8.314472 [J/mol K]. +energy divided by +the +Activation +universal gas constant for the diffusion +reaction +austenite-pearlite +the +reaction: Q3/R. R = 8.314472 [J/mol K]. +for +energy divided by +Activation +the +universal gas constant for the diffusion +reaction for the austenite-bainite reaction: +Q4/R. R = 8.314472 [J/mol K]. +for +Material constant +the martensite +phase. A value of 0.011 means that 90% +of the available austenite is transformed +into martensite at 210 degrees below the +martensite start temperature , whereas a value of +0.033 means a 99.9% transformation. +ASTM grain size number for austenite, +usually a number between 7 and 11. +Number of degrees that the ferrite is +bleeding over into the pearlite reaction. +*MAT_UHS_STEEL +BASELINE VALUE +640 × 106 J/m3 [2] +10324 K [3] = +(23000 cal/mole) × +(4.184 J/cal) / +(8.314 J/mole/K) +13432. K [3] +15068. K [3] +0.011 +6.8 +VARIABLE +DESCRIPTION +BASELINE VALUE +TOFPE +TOFBA +PLMEM2 +PLMEM3 +PLMEM4 +PLMEM5 +Number of degrees that the pearlite is +bleeding over into the bainite reaction +Number of degrees that the bainite is +bleeding over +the martensite +into +reaction. +Memory coefficient for the plastic strain +that is carried over from the austenite. A +value of 1 means that all plastic strains +from austenite is transferred to the ferrite +phase and a value of 0 means that +nothing is transferred. +Same as PLMEM2 but between austenite +and pearlite. +Same as PLMEM2 but between austenite +and bainite. +Same as PLMEM3 but between austenite +and martensite. +STRC +Effective strain rate parameter C. +STRC.LT.0.0: load curve id = -STRC +STRC.GT.0.0: constant value +STRC.EQ.0.0: strain rate NOT active +STRP +Effective strain rate parameter P. +STRP.LT.0.0: load curve id = -STRP +STRP.GT.0.0: constant value +STRP.EQ.0.0: strain rate NOT active +REACT +Flag for advanced reaction kinetics input. +One additional input card is read. +EQ.1.0: Active +EQ.0.0: Inactive +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +TEMPER +AUST +FERR +PEAR +BAIN +MART +GRK +GRQR +TAU1 +GRA +GRB +EXPA +EXPB +GRCC +*MAT_UHS_STEEL +DESCRIPTION +BASELINE VALUE +Flag for tempering input. One additional +input card is read. +EQ.1.0: Active +EQ.0.0: Inactive +If a heating process is initiated at t = 0 +this parameters sets the initial amount of +austenite in the blank. If heating is +activated at t > 0 during a simulation this +value is ignored. Note that, +AUST + FERR + PEAR + BAIN ++ MART = 1.0 +See AUST for description +See AUST for description +See AUST for description +See AUST for description +Growth parameter k (μm2/sec) +Grain growth activation energy (J/mol) +divided by the universal gas constant. +Q/R where R = 8.314472 (J/mol K) +Empirical grain growth parameter 𝑐1 +describing the function τ(T) +Grain growth parameter A +Grain growth parameter B. A table of +recommended values of GRA and GRB is +included in Remark 7. +Grain growth parameter a +Grain growth parameter b +Grain growth parameter with +the +concentration of non-metals in the blank, +weight% of C or N +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +1011 [9] +3 × 104 [9] +2.08 × 108 [9] + [9] + [9] +1.0 [9] +1.0 [9] +[9] +VARIABLE +GRCM +HEATN +TAU2 +DESCRIPTION +BASELINE VALUE +Grain growth parameter with +the +concentration of metals in the blank, +lowest weight% of Cr, V, Nb, Ti, Al. +[9] +Grain growth parameter n +austenite formation +for +the +1.0 [9] +Empirical grain growth parameter 𝑐2 +describing the function τ(T) +4.806 [9] +FS +Manual start temperature Ferrite +GT.0.0: Same +temperature +heating and cooling. +is used +for +LT.0.0: Curve ID: +Different +start +temperatures for cooling and heat- +ing given by load curve ID = -FS. +First ordinate value is used for cool- +ing, last ordinate value for heating. +PS +BS +MS +MSIG +LCEPS23 +Manual start temperature Pearlite. See FS +for description. +Manual start temperature Bainite. See FS +for description. +Manual start temperature Martensite. See +FS for description. +Describes the increase of martensite start +temperature for cooling due to applied +stress. +LT.0: Load Curve ID describes MSIG as +a function of triaxiality (pressure +/ effective stress). +MS* = MS + MSIG × 𝜎eff +Load Curve ID dependent on plastic +strain that scales the activation energy +QR2 and QR3. +QRx = Qx × CEPS23(𝜀pl) / R +BASELINE VALUE +Load Curve ID dependent on plastic +strain that scales the activation energy +QR4. +QR4 = Q4 × LCEPS4(𝜀pl) / R +ID which describe +the martensite +the +Load Curve +increase +start +of +temperature for cooling as a function of +plastic strain. +MS* = MS + MSIG × 𝜎eff + LCEPS5(𝜀pl) +Load curve ID of Vicker hardness vs. +hardness +temperature +calculation. +Bainite +for +Load curve ID of Vicker hardness vs. +for Martensite hardness +temperature +calculation. +Critical cooling rate to detect holding +phase. +Sampling interval for temperature rate +monitoring to detect the holding phase +Annealing temperature start +Annealing temperature end +Birth temperature start +Young’s modulus +material +for ghost (quiet) +Poisson’s ratio for ghost (quiet) material +Thermal expansion coefficient for ghost +(quiet) material +*MAT_244 +VARIABLE +LCEPS4 +LCEPS5 +LCH4 +LCH5 +DTCRIT +TSAMP +TASTART +TAEND +TLSTART +EGHOST +PGHOST +AGHOST +Discussion: +The phase distribution during cooling is calculated by solving the following rate +equation for each phase transition +𝑋̇𝑘 = 𝑔𝑘(𝐺, 𝐶, 𝑇𝑘, 𝑄𝑘)𝑓𝑘(𝑋𝑘), +𝑘 = 2,3,4 +where 𝑔𝑘 is a function, taken from Li et al., dependent on the grain number G, the +chemical composition C, the temperature T and the activation energy Q. Moreover, the +function f is dependent on the actual phase 𝑋𝑘 = 𝑥𝑘/𝑥eq +0.4(𝑋𝑘−1)(1 − 𝑋𝑘)0.4𝑋𝑘, +The true amount of martensite, i.e., 𝑘 = 5, is modelled by using the true amount of the +austenite left after the bainite phase: +𝑓𝑘(𝑋𝑘) = 𝑋𝑘 +𝑘 = 2,3,4 +𝑥5 = 𝑥1[1 − 𝑒−𝛼(MS−𝑇)], +where 𝑥1 is the true amount of austenite left for the reaction, 𝛼 is a material dependent +constant and MS is the start temperature of the martensite reaction. +The start temperatures are automatically calculated based on the composition: +1. Ferrite, + FS = 1185 − 203 × √C − 15.2 × Ni + 44.7 × Si + 104 × V + 31.5 × Mo + 13.1 × W +− 30 × Mn − 11 × Cr − 20 × Cu + 700 × P + 400 × Al + 120 × As ++ 400 × Ti +2. Pearlite, +PS = 996 − 10.7 × Mn − 16.9 × Ni + 29 × Si + 16.9 × Cr + 290 × As + 6.4 × W +3. Bainite, +BS = 910 − 58 × C − 35 × Mn − 15 × Ni − 34 × Cr − 41 × Mo +4. Martensite, +MS = 812 − 423 × C − 30.4 × Mn − 17.7 × Ni − 12.1 × Cr − 7.5 × Mo + 10 × Co +− 7.5 × Si +where the element weight values are input on Cards 2 through 4. +The automatic start temperatures are printed to the messag file and if they are not +accurate enough you can manually set them in the input deck (must be set in absolute +temperature, Kelvin). If HEAT > 0, the temperature FSnc (ferrite without C) is also +echoed. If the specimen exceeds that temperature all ferrite that is left is instantaneous +transformed to austenite. +Remarks: +1. History Variables. History variables 1 through 8 include the different phases, +the Vickers hardness, the yield stress and the ASTM grain size number. Set +NEIPS = 8 (shells) or NEIPH = 8 (solids) on *DATABASE_EXTENT_BINARY. +History +Variable +1 +2 +3 +4 +5 +6 +7 +8 +Description +Amount austenite +Amount ferrite +Amount pearlite +Amount bainite +Amount martensite +Vickers hardness +Yield stress +grain +size +ASTM +number (a low value +means large grains and +vice versa) +2. Excluding Phases. To exclude a phase from the simulation, set the PHASE +parameter accordingly. +3. STRC and STRP. Note that both strain rate parameters must be set to include +the effect. It is possible to use a temperature dependent load curve for both +parameters simultaneously or for one parameter keeping the other constant. +4. TUNIT. TUNIT is time units per hour and is only used for calculating the +Vicker Hardness, as default it is assumed that the time unit is seconds. If other +time unit is used, for example milliseconds, then TUNIT must be changed to +TUNIT = 3.6 × 106 +5. TSF. The thermal speedup factor TSF of *CONTROL_THERMAL_SOLVER is +used to scale reaction kinetics and hardness calculations in this material model. +On the other hand, strain rate dependent properties are not scaled by TSF. +6. CRSH. With the CRSH = 1 option it is now possible to transfer the material +properties from a hot stamping simulation (CRSH = 0) into another simulation. +The CRSH = 1 option reads a dynain file from a simulation with CRSH = 0 and +keeps all the history variables (austenite, ferrite, pearlite, bainite, martensite, +etc) constant. This will allow steels with inhomogeneous strength to be ana- +lysed in, for example, a crash simulation. The speed with the CRSH = 1 option +is comparable with *MAT_024. Note that for keeping the speed the tempera- +ture used in the CRSH simulation should be constant and the thermal solver +should be inactive. +7. HEAT. When HEAT is activated the re-austenitization and grain growth +algorithms are also activated. The grain growth is activated when the tempera- +ture exceeds a threshold value that is given by +𝑇 = +𝐴 − log10[(GRCM)𝑎(GRCC)𝑏] +and the rate equation for the grain growth is, +𝑔̇ = +𝑅𝑇. +− +2𝑔 +The rate equation for the phase re-austenitization is given in Oddy (1996) and is +here mirrored +𝑥̇𝑎 = 𝑛 [ln ( +𝑥𝑒𝑢 +𝑥𝑒𝑢 − 𝑥𝑎 +𝑛−1 +)] +[ +𝑥𝑒𝑢 − 𝑥𝑎 +𝜏(𝑇) +] +where n is the parameter HEATN. The temperature dependent function 𝜏(𝑇) is +given from Oddy as 𝜏(𝑇) = 𝑐1(𝑇 − 𝑇𝑠)𝑐2. The empirical parameters 𝑐1 and 𝑐2 +are calibrated in Oddy to 2.06 × 108 and 4.806 respectively. Note that 𝜏 above +given in seconds. +Recommended values for GRA and GRB are given in the following table. +Compound +Metal +Non-metal +GRA +Cr23C6 +V4C3 +TiC +NbC +Mo2C +Nb(CN) +VN +AlN +NbN +TiN +Cr +V +Ti +Nb +Mo +Nb +V +Al +Nb +Ti +C +C0.75 +C +C0.7 +C +(CN) +N +N +N +N +5.90 +5.36 +2.75 +3.11 +5.0 +2.26 +3.46 + 0.12%Mn +1.03 +4.04 +0.32 +GRB +7375 +8000 +7000 +7520 +7375 +6770 +8330 +6770 +10230 +8000 +8. Using the Table Capability for Temperature Dependence of Young’s +Modulus. Use *DEFINE_TABLE_2D and set the abscissa value equal to 1 for +the austenite YM-curve, equal to 2 for the ferrite YM-curve, equal to 3 for the +pearlite YM curve, equal to 4 for the bainite YM-curve and finally equal to 5 for +the martensite YM-curve. If you use the PHASE option you only need to define +the curves for the included phases, but you can define all five. LS-DYNA uses +the number 1-5 to get the right curve for the right phase. The total YM is calcu- +lated by a linear mixture law: YM = YM1 × PHASE1 + ⋯ + YM5 × PHASE5. +For example: +*DEFINE_TABLE_2D +$ The number before curve id:s define which phase the curve +$ will be applied to. 1 = Austenite, 2 = Ferrite, 3 = Pearlite, +$ 4 = Bainite and 5 = Martensite. + 1000 0.0 0.0 + 1.0 100 + 2.0 200 + 3.0 300 + 4.0 400 + 5.0 500 +$ +$ Define curves 100 - 500 +*DEFINE_CURVE +$ Austenite Temp (K) - YM-Curve (MPa) + 100 0 1.0 1.0 + 1300.0 50.E+3 + 223.0 210.E+3 +9. Using the Table Capability for Latent Heat. When using a table ID for the +latent heat (LAT1) you can describe all phase transition individually. Use *DE- +FINE_TABLE_2D and set the abscissa values to the corresponding phase transi- +tion number. That is, 2 for the austenite to ferrite, 3 for the austenite to pearlite, +4 for the austenite to bainite and 5 for the austenite to martensite. Remark 8 +demonstrates the form a correct table definition. If a curve is missing, the cor- +responding latent heat for that transition will be set to zero. Also, when a table +is used the LAT2 is ignored. If HEAT > 0 you also have the option to include +latent heat for the transition back to Austenite. This latent heat curve is marked +as 1 in the table definition of LAT1. +10. Using the Table Capability for Thermal Expansion. When using a table ID +for the thermal expansion you can specify the expansion characteristics for each +phase. That is, you can have a curve for each of the 5 phases (austenite, ferrite, +pearlite, bainite, and martensite). The input is identical to the above table defi- +nitions. The table must have the abscissa values between 1 and 5 where the +number correspond to phase 1 to 5. To exclude one phase from influencing the +thermal expansion you simply input a curve that is zero for that phase or even +easier, exclude that phase number in the table definition. For example, to ex- +clude the bainite phase you only define the table with curves for the indices 1, 2, +3 and 5. +11. TEMPER. Tempering is activated by setting TEMPER to 1. When active the +default hardness calculation for bainite and martensite is altered to use an in- +cremental update formula. The total hardness is given by ∑ HV𝑖 × 𝑥𝑖 + . When +holding phases are detected the hardness for Bainite and Martensite is updated +according to +𝑖=1 +HV4 +𝑛+1 = +HV5 +𝑛+1 = +𝑥4 +𝑛+1 HV4 +𝑥4 +𝑥5 +𝑛+1 HV5 +𝑥5 +𝑛 + +𝑛 + +∆𝑥4 +𝑛+1 ℎ4(𝑇), +𝑥4 +∆𝑥5 +𝑛+1 ℎ5(𝑇), +𝑥5 +∆𝑥4 = 𝑥4 +𝑛+1 − 𝑥4 +𝑛 +∆𝑥5 = 𝑥5 +𝑛+1 − 𝑥5 +𝑛 +We detect the holding phase for Bainite and Martensite when the temperature +is in the appropriate range and if average temperature rate is below DTCRIT. +𝑛 + +The average temperature rate is calculated as +𝑛 + ∆𝑡. The average temperature and time are updated until +∣𝑇̇∣∆𝑡 and 𝑡tresh +𝑡tresh ≥ 𝑡samp. + where the 𝑇tresh +𝑛+1 = 𝑇tresh +𝑛+1 = 𝑡tresh +𝑇tresh +𝑡tresh +12. CWM (Welding). When computational welding mechanics is activated with +CWM = 1 the material can be defined to be initially in a quiet state. In this state +the material (often referred to as ghost material) has thermo-mechanical proper- +ties defined by an additional card. The material is activated when the tempera- +ture reaches the birth temperature. See MAT_CWM (MAT_270) for a detailed +description. +13. LCTRE (Transformation Induced Strains). Transformation induced strains +can be included with a load curve LCTRE as a function of temperature. The +load curve represents the difference between the hard phases and the austenite +phase in the dilatometer curves. Therefore, positive curve values result in a +negative transformation strain for austenitization and a positive transformation +strain for the phase transformation from austenite to one of the hard phases. +References: +1. Numisheet 2008 Proceedings, The Numisheet 2008 Benchmark Study, Chapter +3, Benchmark 3, Continuous Press Hardening, Interlaken, Switzerland, Sept. +2008. +2. P. Akerstrom and M. Oldenburg, “Austenite Decomposition During Press +hardening of a Boron Steel – Computer Simulation and Test”, Journal of Mate- +rial processing technology, 174 (2006), pp399-406. +3. M.V Li, D.V Niebuhr, L.L Meekisho and D.G Atteridge, “A Computatinal +model for te prediction of steel hardenability”, Metallurgical and materials +transactions B, 29B, 661-672, 1998. +4. D.F. Watt, “An Algorithm for Modelling Microstructural Development in Weld +heat-Affected Zones (Part A) Reaction Kinetics”, Acta metal. Vol. 36., No. 11, +pp. 3029-3035, 1988. +5. ThyssenKrupp Steel, “Hot Press hardening Manganese-boron Steels MBW”, +product information Manganese-boron Steels, Sept. 2008. +6. Malek Naderi, “Hot Stamping of Ultra High Strength Steels”, Doctor of +Engineering Dissertation, Technical University Aachen, Germany, 2007. +7. P. Akerstrom, “Numerical Implementation of a Constitutive model for +Simulation of Hot Stamping”, Division of Solid Mechanics, Lulea University of +technology, Sweden. +8. Malek Naderi, “A numerical and Experimental Investigation into Hot Stamping +of Boron Alloyed Heat treated Steels”, Steel research Int. 79 (2008) No. 2. +9. A.S. Oddy, J.M.J. McDill and L. Karlsson, “Microstructural predictions +including arbitrary thermal histories, reaustenitization and carbon segregation +effects” (1996). +Boron steel composition from the literature: +Element +HAZ code +Akerstrom (2) +Naderi (8) +ThyssenKrupp(4) +(max amount) +B +C +Co +Mo +Cr +Ni +Mn +Si +V +W +Cu +P +Al +As +Ti +S +0.168 +0.036 +0.255 +0.015 +1.497 +0.473 +0.026 +0.025 +0.012 +0.020 +0.003 +0.23 +0.211 +1.25 +0.29 +0.003 +0.230 +0.160 +1.18 +0.220 +0.005 +0.250 +0.250 +0.250 +1.40 +0.400 +0.013 +0.015 +0.025 +0.003 +0.040 +0.001 +0.05 +0.010 +*MAT_PML_OPTIONTROPIC_ELASTIC +This is Material Type 245. This is a perfectly-matched layer (PML) material for +orthotropic or anisotropic media, to be used in a wave-absorbing layer adjacent to an +orthotropic/anisotropic material (*MAT_{OPTION}TROPIC_ELASTIC) in order to +simulate wave propagation in an unbounded ortho/anisotropic medium. +This material is a variant of MAT_PML_ELASTIC (MAT_230) and is available only for +solid 8-node bricks +follow +*MAT_{OPTION}TROPIC_ELASTIC as shown below. See the variable descriptions and +Remarks section of *MAT_{OPTION}TROPIC_ELASTIC (*MAT_002) for further details. +input cards exactly +type 2). +(element + The +Available options include: +ORTHO +ANISO +such that the keyword cards appear: +*MAT_PML_ORTHOTROPIC_ELASTIC or MAT_245 +(4 cards follow) +*MAT_PML_ANISOTROPIC_ELASTIC or MAT_245_ANISO +(5 cards follow) +Orthotropic Card 1. Card 1 format used for ORTHO keyword option. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +EA +F +4 +EB +F +5 +EC +F +6 +7 +8 +PRBA +PRCA +PRCB +F +F +F +Orthotropic Card 2. Card 2 format used for ORTHO keyword option. + Card 2 +1 +2 +3 +4 +Variable +GAB +GBC +GCA +AOPT +Type +F +F +F +F +5 +G +F +6 +7 +8 +SIGF +Anisotropic Card 1. Card 1 format used for ANISO keyword option. + Card 1 +1 +Variable +MID +2 +RO +3 +4 +5 +6 +7 +8 +C11 +C12 +C22 +C13 +C23 +C33 +Type +A8 +F +F +F +F +F +F +F +Anisotropic Card 2. Card 2 format used for ANISO keyword option. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +C14 +C24 +C34 +C44 +C15 +C25 +C35 +C45 +Type +F +F +F +F +F +F +F +F +Anisotropic Card 3. Card 3 format used for ANISO keyword option. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +C55 +C16 +C26 +C36 +C46 +C56 +C66 +AOPT +Type +F +F +F +F +F +F + Card 4 +Variable +1 +XP +Type +F + Card 5 +Variable +1 +V1 +Type +F +2 +YP +F +2 +V2 +F +3 +ZP +F +3 +V3 +F +4 +A1 +F +4 +D1 +F +5 +A2 +F +5 +D2 +F +6 +A3 +F +6 +D3 +F +F +7 +MACF +I +7 +F +8 +8 +BETA +REF +F +Remarks: +1. A layer of this material may be placed at a boundary of a bounded domain to +simulate unboundedness of the domain at that boundary: the layer absorbs and +attenuates waves propagating outward from the domain, without any signifi- +cant reflection of the waves back into the bounded domain. The layer cannot +support any static displacement. +2. +It is assumed the material in the bounded domain near the layer is, or behaves +like, a linear ortho/anisotropic material. The material properties of the layer +should be set to the corresponding properties of this material. +3. The layer should form a cuboid box around the bounded domain, with the axes +of the box aligned with the coordinate axes. Various faces of this box may be +open, as required by the geometry of the problem, e.g., for a half-space prob- +lem, the “top” of the box should be open. +4. +Internally, LS-DYNA will partition the entire PML into regions which form the +“faces”, “edges” and “corners” of the above cuboid box, and generate a new +material for each region. This partitioning will be visible in the d3plot file. The +user may safely ignore this partitioning. +5. The layer should have 5 - 10 elements through its depth. Typically, 5 - 6 +elements are sufficient if the excitation source is reasonably distant from the +layer, and 8 - 10 elements if it is close. The size of the elements should be simi- +lar to that of elements in the bounded domain near the layer, and should be +small enough to sufficiently discretize all significant wavelengths in the prob- +lem. +6. The nodes on the outer boundary of the layer should be fully constrained. +7. The stress and strain values reported by this material do not have any physical +significance. +*MAT_PML_NULL +This is Material Type 246. This is a perfectly-matched layer (PML) material with a +pressure fluid constitutive law computed using an equation of state, to be used in a +wave-absorbing layer adjacent to a fluid material (*MAT_NULL with an EOS) in order +to simulate wave propagation in an unbounded fluid medium. Only *EOS_LINEAR_- +POLYNOMIAL and *EOS_GRUNEISEN are allowed with this material. See the +Remarks section of *MAT_NULL (*MAT_009) for further details. Accurate results are +to be expected only for the case where the EOS presents a linear relationship between +the pressure and volumetric strain. +This material is a variant of MAT_PML_ELASTIC (MAT_230) and is available only for +solid 8-node bricks (element type 2). +4 +5 +6 +7 +8 +Card +1 +Variable +MID +2 +RO +3 +MU +Type +A8 +F +F +Default +none +none +0.0 + VARIABLE +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Dynamic viscosity coefficient +MID +RO +MU +Remarks: +1. A layer of this material may be placed at a boundary of a bounded domain to +simulate unboundedness of the domain at that boundary: the layer absorbs and +attenuates waves propagating outward from the domain, without any signifi- +cant reflection of the waves back into the bounded domain. The layer cannot +support any static displacement. +2. +It is assumed the material in the bounded domain near the layer is, or behaves +like, an linear fluid material. The material properties of the layer should be set +to the corresponding properties of this material. +3. The layer should form a cuboid box around the bounded domain, with the axes +of the box aligned with the coordinate axes. Various faces of this box may be +open, as required by the geometry of the problem, e.g., for a half-space prob- +lem, the “top” of the box should be open. +4. +Internally, LS-DYNA will partition the entire PML into regions which form the +“faces”, “edges” and “corners” of the above cuboid box, and generate a new +material for each region. This partitioning will be visible in the d3plot file. The +user may safely ignore this partitioning. +5. The layer should have 5-10 elements through its depth. Typically, 5-6 elements +are sufficient if the excitation source is reasonably distant from the layer, and 8- +10 elements if it is close. The size of the elements should be similar to that of +elements in the bounded domain near the layer, and should be small enough to +sufficiently discretize all significant wavelengths in the problem. +6. The nodes on the outer boundary of the layer should be fully constrained. +7. The stress and strain values reported by this material do not have any physical +significance. +*MAT_PHS_BMW +This is Material Type 248. This model is intended for hot stamping processes with +phase transformation effects. It is available for shell elements only and is based on +Material Type 244 (*MAT_UHS_STEEL). As compared with Material Type 244 Material +Type 248 features: +1. +2. +3. +a more flexible choice of evolution parameters, +an approach for transformation induced strains, +and a more accurate density calculation of individual phases. +Thus the metal physical effects can be taken into account calculating the volume +fractions of ferrite, pearlite, bainite and martensite for fast supercooling as well as for +slow cooling conditions. Furthermore, this material model features cooling-rate +dependence for several of its more crucial material parameters in order to accurately +calculate the Time-Temperature-Transformation diagram dynamically. A detailed +description can be found in Hippchen et al. [2013] and Hippchen [2014]. +NOTE 1: For this material “weight%” means +“ppm × 10-4”. +NOTE 2: For this material the phase frac- +tions are calculated in volume per- +cent (vol%). + Card 1 +1 +Variable +MID +Type +I +2 +RO +F +3 +E +F +4 +PR +F +Defaults +none +none +none +none +3600 +5 +6 +7 +8 +TUNIT +TRIP +PHASE +HEAT +F +I +0 +I +0 +I +Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCY1 +LCY2 +LCY3 +LCY4 +LCY5 +C_F +C_P +C_B +Type +I +I +I +I +I +F +F +F +Defaults +none +none +none +none +none +0.0 +0.0 +0.0 + Card 3 +Variable +Type +1 +C +F +2 +Co +F +3 +Mo +F +4 +Cr +F +5 +Ni +F +6 +Mn +F +7 +Si +F +8 +V +F +Defaults +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 4 +Variable +Type +1 +W +F +2 +Cu +F +3 +P +F +4 +Al +F +5 +As +F +6 +Ti +F +7 +B +F +8 +Defaults +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +Defaults +TABRHO +TREF +LAT1 +LAT5 +TABTH +I +F +F +F +I +none +none +0.0 +0.0 +none +Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +QR2 +QR3 +QR4 +ALPHA +GRAIN +TOFFE +TOFPE +TOFBA +Type +F +F +F +F +F +F +F +F +Defaults +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 7 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PLMEM2 PLMEM3 PLMEM4 PLMEM5 +STRC +STRP +Type +F +F +F +F +F +F +Defaults +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 8 +Variable +1 +FS +Type +F +2 +PS +F +3 +BS +F +4 +5 +6 +7 +8 +MS +MSIG +LCEPS23 +LCEPS4 +LCEPS5 +F +F +I +I +I +Defaults +0.0 +0.0 +0.0 +0.0 +none +none +none +none + Card 9 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCH4 +LCH5 +DTCRIT +TSAMP +ISLC +IEXTRA +Type +Defaults +I +0 +I +0 +F +F +0.0 +0.0 +I +0 +I +Card 10 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ALPH_M +N_M +PHI_M +PSI_M +OMG_F +PHI_F +PSI_F +CR_F +Type +F +F +F +F +F +F +F +F +Defaults +0.0428 +0.191 +0.382 +2.421 +0.41 +0.4 +0.4 +0.0 + Card 11 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +OMG_P +PHI_P +PSI_P +CR_P +OMG_B +PHI_B +PSI_B +CR_B +Type +F +F +F +F +F +F +F +F +Defaults +0.32 +0.4 +0.4 +0.0 +0.29 +0.4 +0.4 +0.0 +Heat Card 1. Additional Card for HEAT ≠ 0. + Card 12 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +AUST +FERR +PEAR +BAIN +MART +GRK +GRQR +TAU1 +Type +F +F +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +2.08E+8 +Heat Card 2. Additional Card for HEAT ≠ 0. + Card 13 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +GRA +GRB +EXPA +EXPB +GRCC +GRCM +HEATN +TAU2 +Type +F +F +F +F +F +F +F +F +Default +3.11 +7520. +1.0 +1.0 +none +none +1.0 +4.806 +Extra Card 1. Additional Card for IEXTRA = 1. + Card 14 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FUNCA +FUNCB +FUNCM +TCVUP +TCVLO +CVCRIT +TCVSL +Type +F +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Extra Card 2. Additional Card for IEXTRA = 2. + Card 15 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EPSP +EXPON +Type +F +F +Default +0.0 +0.0 +VARIABLE +DESCRIPTION +BASELINE VALUE +MID +RO +Material ID, a unique number has to be +chosen. +Material density at room temperature +(necessary for calculating transformation +induced strains) +7830 Kg/m3 +E +Youngs’ modulus: +100.e+09 Pa [1] +GT.0.0: constant value is used +LT.0.0: LCID or TABID. Temperature +dependent Young’s modulus +given by load curve or table +ID = -E. When using a table to +describe the Young’s modulus +see Remark 10 for more infor- +mation. +VARIABLE +DESCRIPTION +BASELINE VALUE +PR +Poisson’s ratio: +0.30 [1] +3600. +0 +0 +TUNIT +TRIP +PHASE +GT.0.0: constant value is used +LT.0.0: LCID or TABID. Temperature +dependent Poisson’s ratio giv- +en by load curve or table ID = - +PR. The table input is de- +scribed in Remark 10. +Number of time units per hour. Default +is seconds, that is 3600 time units per +hour. + It is used only for hardness +calculations. +Flag to activate (0) or deactivate (1) trip +effect calculation. +Switch to exclude middle phases from the +simulation. +EQ.0: all phases active (default) +EQ.1: pearlite and bainite active +EQ.2: bainite active +EQ.3: ferrite and pearlite active +EQ.4: ferrite and bainite active +EQ.5: no active middle phases +(only austenite → martensite) +HEAT +Heat flag as in MAT_244, see there for +details. +EQ.0: Heating is not activated. +EQ.1: Heating is activated. +EQ.2: Automatic switching between +cooling and heating. +LT.0: Switch between cooling and +heating is defined by a time de- +id +pendent +ABS(HEAT). +load curve with +LCY1 +LCY2 +LCY3 +LCY4 +LCY5 +C_F +C_P +C_B +C +Co +Mo +*MAT_PHS_BMW +DESCRIPTION +BASELINE VALUE +Load curve or Table ID for austenite +hardening. +if LCID +input yield stress versus effective +plastic strain. +if TABID.GT.0: +2D table. Input temperatures as table +values and hardening curves as +targets for those temperatures +if TABID.LT.0: +3D table. Input temperatures as main +table values and strain rates as values +for the sub tables, and hardening +curves as targets for those strain rates. +Load curve or Table ID for ferrite. See +LCY1 for description. +Load curve or Table ID for pearlite. See +LCY1 for description. +Load curve or Table ID for bainite. See +LCY1 for description. +Load curve or Table ID for martensite. +See LCY1 for description. +for ferrite +Alloy dependent factor 𝐶𝑓 +(controls the alloying effects beside of +Boron +time-temperature- +the +transformation start line of ferrite). +on +Alloy dependent factor 𝐶𝑝 for pearlite +. +Alloy dependent factor 𝐶𝑏 for bainite . +Carbon [weight %] +Cobolt [weight %] +Molybdenum [weight %] +[5] +0.23 [2, 4] +0.0 [2, 4] +0.0 [2, 4] +VARIABLE +DESCRIPTION +BASELINE VALUE +Cr +Ni +Mn +Si +V +W +Cu +P +Al +As +Ti +Β +TABRHO +TREF +LAT1 +Chromium [weight %] +Nickel [weight %] +Manganese [weight %] +Silicon [weight %] +Vanadium [weight %] +Tungsten [weight %] +Copper [weight %] +Phosphorous [weight %] +Aluminium [weight %] +Arsenic [weight %] +Titanium [weight %] +Boron [weight %] +for +definition +and +Table +temperature +densities. +Needed for calculation of transformation +induced strains. +dependent +phase +temperature +Reference +thermal +expansion (only necessary for thermal +expansion calculation with the secant +method). +for +0.21 [2, 4] +0.0 [2, 4] +1.25 [2, 4] +0.29 [2, 4] +0.0 [2, 4] +0.0 +0.0 +0.013 +0.0 +0.0 +0.0 +0.0 +293.15 +Latent heat for the decomposition of +austenite into ferrite, pearlite and bainite. +GT.0.0: Constant value +590.e+06 J/m3 [2] +LT.0.0: Curve ID or Table ID: See +infor- +for more +remark 11 +mation. +640.e+06 J/m3 [2] +*MAT_248 +VARIABLE +LAT5 +DESCRIPTION +Latent heat for the decomposition of +austenite into martensite. +GT.0.0: Constant value +LT.0.0: Curve ID: Note that LAT 5 is +ignored if a Table ID is used in +LAT1. +TABTH +Table definition for thermal expansion +coefficient. +for more + See remarks +information how to input this table. +QR2 +QR3 +QR4 +ALPHA +GT.0: A +for +table +instantaneous +thermal expansion (TREF is ig- +nored). +LT.0: A table with thermal expansion +with reference to TREF. +energy divided by +Activation +the +universal gas constant for the diffusion +reaction of the austenite-ferrite reaction: +Q2/R. R = 8.314472 [J/mol K]. +energy divided by +the +Activation +universal gas constant for the diffusion +reaction +austenite-pearlite +the +reaction: Q3/R. R = 8.314472 [J/mol K]. +for +energy divided by +Activation +the +universal gas constant for the diffusion +reaction for the austenite-bainite reaction: +Q4/R. R = 8.314472 [J/mol K]. +for +Material constant +the martensite +phase. A value of 0.011 means that 90% +of the available austenite is transformed +into martensite at 210 degrees below the +, whereas a +value +99.9% +0.033 means +transformation. +temperature +start +of +a +10324 K [3] = +(23000 cal/mole) × +(4.184 J/cal) / +(8.314 J/mole/K) +13432. K [3] +15068. K [3] +0.011 +GRAIN +ASTM grain size number 𝐺 for austenite, +usually a number between 7 and 11. +6.8 +DESCRIPTION +BASELINE VALUE +VARIABLE +TOFFE +TOFPE +TOFBA +PLMEM2 +PLMEM3 +PLMEM4 +PLMEM5 +STRC +Number of degrees that the ferrite is +bleeding over into the pearlite reaction: +𝑇off,𝑓 . +Number of degrees that the pearlite is +bleeding over into the bainite reaction: +𝑇off,𝑝. +Number of degrees that the bainite is +the martensite +into +bleeding over +reaction: 𝑇off,𝑏. +Memory coefficient for the plastic strain +that is carried over from the austenite. A +value of 1 means that all plastic strains +from austenite is transferred to the ferrite +phase and a value of 0 means that +nothing is transferred. +Same as PLMEM2 but between austenite +and pearlite. +Same as PLMEM2 but between austenite +and bainite. +Same as PLMEM3 but between austenite +and martensite. +Cowper +parameter 𝐶. +and Symonds +strain +rate +STRC.LT.0.0: load curve id = -STRC +STRC.GT.0.0: constant value +STRC.EQ.0.0: strain rate NOT active +STRP +Cowper +parameter P. +and Symonds +strain +rate +STRP.LT.0.0: load curve id = -STRP +STRP.GT.0.0: constant value +STRP.EQ.0.0: strain rate NOT active +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +VARIABLE +DESCRIPTION +BASELINE VALUE +FS +Manual start temperature ferrite, 𝐹𝑆. +GT.0.0: Same temperature is used for +heating and cooling. +LT.0.0: Curve ID: Different +start +temperatures for cooling and +heating given by load curve +ID = -FS. First ordinate value is +used for cooling, last ordinate +value for heating. +Manual start temperature pearlite, 𝑃𝑆. +See FS for description. +Manual start temperature bainite, 𝐵𝑆. See +FS for description. +Manual start temperature martensite, 𝑀𝑆. +See FS for description. +Describes the increase of martensite start +temperature for cooling due to applied +stress. +LT.0: Load Curve ID describes MSIG as +a function of triaxiality (pressure +/ effective stress). +MS* = MS + MSIG × 𝜎eff +Load Curve ID dependent on plastic +strain that scales the activation energy +QR2 and QR3. +QRn = Qn × LCEPS23(𝜀pl)/𝑅 +Load Curve ID dependent on plastic +strain that scales the activation energy +QR4. +QR4 = Q4 × LCEPS4(𝜀pl)/𝑅 +PS +BS +MS +MSIG +LCEPS23 +LCEPS4 +VARIABLE +LCEPS5 +LCH4 +LCH5 +DTCRIT +TSAMP +ISLC +DESCRIPTION +BASELINE VALUE +ID which describe +the martensite +the +Load Curve +increase +start +of +temperature for cooling as a function of +plastic strain. +MS* = MS + MSIG × 𝜎eff + LCEPS5(𝜀pl) +Load curve ID of Vickers hardness vs. +temperature +hardness +calculation. +bainite +for +Load curve ID of Vickers hardness vs. +temperature +for martensite hardness +calculation. +Critical cooling rate to detect holding +phase. +Sampling interval for temperature rate +monitoring to detect the holding phase +for +Flag +parameters on Cards 10 and 11. +definition +of +evolution +EQ.0.0: All 16 parameters on Cards 10 +and 11 are constant values. +EQ.1.0: PHI_F, CR_F, PHI_P, CR_P, +PHI_B, and CR_B are load +curves defining values as +functions of cooling rate. The +remaining 10 paramters on +Cards 10 and 11 are constant +values. +EQ.2.0: All 16 parameters on Cards 10 +and 11 are load curves defin- +ing values as functions of cool- +ing rate. +IEXTRA +Flag to read extra cards +ALPH_M +Martensite evolution parameter 𝛼𝑚 +N_M +PHI_M +Martensite evolution parameter 𝑛𝑚 +Martensite evolution parameter 𝜑𝑚 +0.0428 +0.191 +0.382 +PSI_M +OMG_F +PHI_F +PSI_F +CR_F +OMG_P +PHI_P +PSI_P +CR_P +OMG_B +PHI_B +PSI_B +CR_B +*MAT_PHS_BMW +DESCRIPTION +BASELINE VALUE +Martensite evolution exponent 𝜓𝑚, +𝜓𝑚 < 0 then 𝜓𝑚 = ∣𝜓𝑚∣(2 − 𝜍𝑎) +if +Ferrite grain size factor 𝜔𝑓 (mainly +controls the alloying effect of Boron on +the time-temperature-transformation start +line of ferrite) +Ferrite evolution parameter 𝜑𝑓 (controls +the incubation time till 1vol% of ferrite is +built) +Ferrite evolution parameter 𝜓𝑓 (controls +the time till 99vol% of ferrite is built +without effect on the incubation time) +evolution +parameter +Ferrite +𝐶𝑟,𝑓 +(retardation coefficient to influence the +kinetics of phase transformation of ferrite, +should be determined at slow cooling +in +conditions, can also be defined +dependency to the cooling rate) +Pearlite grain size factor 𝜔𝑝 +Pearlite evolution parameter 𝜑𝑝 +PHI_F for description) + +Pearlite evolution parameter 𝐶𝑟,𝑝 +Bainite grain size factor 𝜔𝑏 +Bainite evolution parameter 𝜑𝑏 +Bainite evolution parameter 𝜓𝑏 +Bainite evolution parameter 𝐶𝑟,𝑏 +CR_F for description) +(see +2.421 +0.41 +0.4 +0.4 +0.0 +0.32 +0.4 +0.4 +0.0 +0.32 +0.4 +0.4 +0.0 +DESCRIPTION +BASELINE VALUE +VARIABLE +AUST +FERR +PEAR +BAIN +MART +GRK +GRQR +TAU1 +GRA +GRB +EXPA +EXPB +GRCC +GRCM +If a heating process is initiated at t = 0 +this parameters sets the initial amount of +austenite in the blank. If heating is +activated at t > 0 during a simulation this +value is ignored. Note that, +AUST + FERR + PEAR ++ BAIN + MART += 1.0 +See AUST for description +See AUST for description +See AUST for description +See AUST for description +Growth parameter k (μm2/sec) +Grain growth activation energy (J/mol) +divided by the universal gas constant. +Q/R where R = 8.314472 (J/mol K) +Empirical grain growth parameter 𝑐1 +describing the function τ(T) +Grain growth parameter A +Grain growth parameter B. A table of +recommended values of GRA and GRB is +included in Remark 7 of *MAT_244. +Grain growth parameter 𝑎 +Grain growth parameter 𝑏 +Grain growth parameter with +the +concentration of non metals in the blank, +weight% of C or N +Grain growth parameter with +the +concentration of metals in the blank, +lowest weight% of Cr, V, Nb, Ti, Al. +0.0 +0.0 +0.0 +0.0 +0.0 +1.0E+11[9] +3.0E+4[9] +2.08E+8 [9] + [9] + [9] +1.0 [9] +1.0 [9] + [9] + [9] +1.0[9] +HEATN +Grain growth parameter 𝑛 for +austenite formation +the +BASELINE VALUE +Empirical grain growth parameter 𝑐2 +describing the function τ(T) +4.806[9] +ID of a +saturation +approach) +*DEFINE_FUNCTION +stress A +for +(Hockett-Sherby +ID of a *DEFINE_FUNCTION for initial +yield stress B (Hockett-Sherby approach) +ID of a +saturation +approach) +*DEFINE_FUNCTION +rate M +for +(Hockett-Sherby +Upper temperature for determination of +average cooling velocity +Lower temperature for determination of +average cooling velocity +Critical cooling velocity. If the average +cooling velocity +is smaller or equal +CVCRIT, the cooling rate at TCVSL is +used. +Temperature for determination of cooling +velocity for small cooling velocities. +Plastic strain in Hockett-Sherby approach +Exponent in Hockett-Sherby approach +*MAT_248 +VARIABLE +TAU2 +FUNCA +FUNCB +FUNCM +TCVUP +TCVLO +CVCRIT +TCVSL +EPSP +EXPON +Remarks: +1. Start Temperatures. Start temperatures for ferrite, pearlite, bainite, and +martensite can be defined manually via FS, PS, BS, and MS. Or they are initially +defined using the following composition equations: +𝐹𝑆 = 273.15 + 912 − 203 × √C − 15.2 × Ni + 44.7 × Si + 104 × V + 31.5 × Mo ++ 13.1 × W − 30 × Mn − 11 × Cr − 20 × Cu + 700 × P + 400 × Al ++ 120 × As + 400 +𝑃𝑆 = 273.15 + 723 − 10.7 × Mn − 16.9 × Ni + 29 × Si + 16.9 × Cr + 290 × As ++ 6.4 × W +𝐵𝑆 = 273.15 + 637 − 58 × C − 35 × Mn − 15 × Ni − 34 × Cr − 41 × Mo +𝑀𝑆 = 273.15 + 539 − 423 × C − 30.4 × Mn − 17.7 × Ni − 12.1 × Cr − 7.5 × Mo ++ 10 × Co − 7.5 × Si +2. Martensite Phase Evolution. Martensite phase evolution according to Lee et +al. [2008, 2010] if PSI_M > 0: +d𝜉𝑚 +d𝑇 += α𝑚(𝑀𝑆 − 𝑇)𝑛𝜉𝑚 +𝜑𝑚(1 − 𝜉𝑚)𝜓𝑚 +Martensite phase evolution according to Lee et al. [2008, 2010] with extension +by Hippchen et al. [2013] if PSI_M < 0: +d𝜉𝑚 +d𝑇 += α𝑚(𝑀𝑆 − 𝑇)𝑛𝜉𝑚 +𝜑𝑚(1 − 𝜉𝑚)𝜓𝑚(2−𝜁𝑎) +3. Phase Change Kinetics for Ferrite, Pearlite and Bainite. +d𝜉𝑓 +d𝑡 += 2𝜔𝑓 𝐺 +exp (− +𝑄𝑓 +𝑅𝑇 +) +𝐶𝑓 +(𝐹𝑆 − 𝑇)3 +𝜓𝑓 𝜉𝑓 +𝜉 𝜑𝑓 (1−𝜉𝑓 )(1 − 𝜉𝑓 ) +2) +exp(𝐶𝑟,𝑓 𝜉𝑓 +for 𝐹𝑆 ≥ 𝑇 ≥ (𝑃𝑆 − 𝑇off,𝑓 ) +d𝜉𝑝 +d𝑡 += 2𝜔𝑝𝐺 +exp (− +𝑄𝑝 +𝑅𝑇 +) +𝐶𝑝 +(𝑃𝑆 − 𝑇)3 +𝜓𝑝𝜉𝑝 +𝜉 𝜑𝑝(1−𝜉𝑝)(1 − 𝜉𝑝) +2) +exp(𝐶𝑟,𝑝𝜉𝑝 +for 𝑃𝑆 ≥ 𝑇 ≥ (𝐵𝑆 − 𝑇off,𝑝) +d𝜉𝑏 +d𝑡 += 2𝜔𝑏𝐺 +exp (− +𝑄𝑏 +𝑅𝑇 +) +𝐶𝑏 +(𝐵𝑆 − 𝑇)2 𝜉 𝜑𝑏(1−𝜉𝑏)(1 − 𝜉𝑏)𝜓𝑏𝜉𝑏 +exp(𝐶𝑟,𝑏𝜉𝑏 +2) +for 𝑀𝑆 ≥ 𝑇 ≥ (𝑀𝑆 − 𝑇off,𝑏) +4. History Variables. History variables of this material model are listed in the +following table. To be able to post-process that data, parameters NEIPS (shells) +or NEIPH (solids) have to be defined on *DATABASE_EXTENT_BINARY. +History +Variable +Description +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +11 +12 +13 +17 +19 +25 +26 +Amount austenite +Amount ferrite +Amount pearlite +Amount bainite +Amount martensite +Vickers hardness +Yield stress +ASTM grain size number +Young’s modulus +Saturation stress A (H-S approach) +Initial yield stress B (H-S approach) +Saturation rate M (H-S approach) +Yield stress of H-S approach +𝜎𝑦 = 𝐴 − (𝐴 − 𝐵) ∙ 𝑒−𝑀∙𝐸𝑃𝑆𝑃𝐸𝑋𝑃𝑂𝑁 +Temperature rate +Current temperature +Plastic strain rate +Effective thermal expansion coefficient +5. Choosing/Excluding Phases. To exclude a phase from the simulation, set the +PHASE parameter accordingly. +6. Strain Rate Effects. Note that both strain rate parameters (STRC and STRP) +must be set to include the effect. It is possible to use a temperature dependent +load curve for both parameters simultaneously or for one parameter keeping +the other constant. +7. Time Units. TUNIT is time units per hour and is only used for calculating the +Vicker Hardness, as default it is assumed that the time unit is seconds. If other +time unit is used, for example milliseconds, then TUNIT must be changed to +TUNIT = 3.6 × 106 +8. Thermal Speedup Factor. The thermal speedup factor TSF of *CONTROL_- +THERMAL_SOLVER is used to scale reaction kinetics and hardness calcula- +tions in this material model. On the other hand, strain rate dependent +properties are not scaled by TSF. +9. Re-austenization and Grant Growth with HEAT Option. When HEAT is +activated the re-austenitization and grain growth algorithms are also activated. +See MAT_244 for details. +10. Phase Indexed Tables. When using a Table ID for describing the Young’s +modulus as dependent on the temperature Use *DEFINE_TABLE_2D and set +the abscissa value equal to 1 for the austenite YM-curve, equal to 2 for the fer- +rite YM-curve, equal to 3 for the pearlite YM curve, equal to 4 for the bainite +YM-curve and finally equal to 5 for the martensite YM-curve. When using the +PHASE option only the curves for the included phases are required, but all five +phases may be included. The total YM is calculated by a linear mixture law: +YM = YM1 × PHASE1 + ⋯ + YM5 × PHASE5 +For example: +*DEFINE_TABLE_2D +$ The number before curve id:s define which phase the curve +$ will be applied to. 1 = Austenite, 2 = Ferrite, 3 = Pearlite, +$ 4 = Bainite and 5 = Martensite. + 1000 0.0 0.0 + 1.0 100 + 2.0 200 + 3.0 300 + 4.0 400 + 5.0 500 +$ +$ Define curves 100 - 500 +*DEFINE_CURVE +$ Austenite Temp (K) - YM-Curve (MPa) + 100 0 1.0 1.0 + 1300.0 50.E+3 + 223.0 210.E+3 +11. Phase-indexed Latent Heat Table. A Table ID may be specified for the Latent +heat (LAT1) to describe each phase change individually. Use *DEFINE_TA- +BLE_2D and set the abscissa values to the corresponding phase transition num- +ber. That is, 2 for the Austenite – Ferrite, 3 for the Austenite – Pearlite,’4’ for the +Austenite – Bainite and 5 for the Austenite – Martensite. See Remark 7 for an +example of a correct table definition. If a curve is missing, the corresponding +latent heat for that transition will be set to zero. Also, when a table is used the +LAT2 is ignored. If HEAT.GT.0 you also have the option to include latent heat +for the transition back to Austenite. This latent heat curve is marked as 1 in the +table definition of LAT1. +12. Phase-indexed Thermal Expansion Table. Tables are supported for defining +different thermal expansion properties for each phase. The input is identical to +the above table definitions. The Table must have the abscissa values between 1 +and 5 where the number correspond to phase 1 to 5. To exclude one phase from +influencing the thermal expansion you simply input a curve that is zero for that +phase or even easier, exclude that phase number in the table definition. For +example to exclude the bainite phase you only define the table with curves for +the indices 1, 2, 3 and 5. +13. Phase-indexed Transformation Induced Strain Properties. Transformation +induced strains can be define with a table TABRHO, where densities are de- +fined as functions of phase (table abscissas) and temperature (load curves). +*MAT_REINFORCED_THERMOPLASTIC +This is material type 249. This material model describes a reinforced thermoplastic +composite material. The reinforcement is defined as an anisotropic hyper-elastic +material with up to three distinguished fiber directions. It can be used to model +unidirectional layers as well as woven and non-crimped fabrics. The matrix is modeled +with a simple thermal elasto-plastic material formulation. For a composite an additive +composition of fiber and matrix stresses is used. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +Variable +NFIB +AOPT +Type +I +F + Card 3 +Variable +1 +V1 +Type +F + Card 4 +1 +2 +V2 +F +2 +3 +4 +5 +6 +7 +8 +EM +LCEM +PRM +LCPRM +LCSIGY +BETA +F +I +F +I +I +F +3 +XP +F +3 +V3 +F +3 +4 +YP +F +4 +D1 +F +4 +5 +ZP +F +5 +D2 +F +5 +6 +A1 +F +6 +7 +A2 +F +7 +8 +A3 +F +8 +D3 +MANGL +THICK +F +6 +F +7 +F +8 +Variable +IDF1 +ALPH1 +EF1 +LCEF1 +G23_1 +G31_1 +Type +I +F +F +I +F +Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +G12 +LCG12 +ALOC12 GLOC12 METH12 +Type +F + Card 6 +1 +I +2 +F +3 +F +4 +I +5 +6 +7 +8 +Variable +IDF2 +ALPH2 +EF2 +LCEF2 +G23_2 +G31_2 +Type +I + Card 7 +1 +F +2 +F +3 +I +4 +F +5 +F +6 +7 +8 +Variable +G23 +LCG23 +ALOC23 GLOC23 METH23 +Type +F + Card 8 +1 +I +2 +F +3 +F +4 +I +5 +6 +7 +8 +Variable +IDF3 +ALPH3 +EF3 +LCEF3 +G23_3 +G31_3 +Type +I +F +F +I +F +F +The following card is optional + Card 9 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +POSTV +Type +F + VARIABLE +MID +2-1256 (MAT_248) +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +VARIABLE +DESCRIPTION +RO +EM +LCEM +PR +LCPR +Density. +Young’s modulus of matrix material. +Curve ID for Young’s modulus of matrix material versus +temperature. With this option active, EM is ignored. +Poisson’s ratio for matrix material +Curve +temperature. With this option active, PR is ignored. +for Poisson’s ratio of matrix material versus +ID +LCSIGY +Load curve or table ID for strain hardening of the matrix. +IF LCSIGY refers to a curve +Input yield stress versus effective plastic strain. +IF LCSIGY refers to a table: +Input temperatures as table values and hardening curves +as targets for those temperatures +BETA +Parameter for mixed hardening. Set 𝛽 = 0 for pure kinematic +hardening and 𝛽 = 1 for pure isotropic hardening. +NFIB +Number of fiber families to be considered. +AOPT +*MAT_REINFORCED_THERMOPLASTIC +DESCRIPTION +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes, as with *DEFINE_COORDI-NATE_- +NODES, and then rotated about the shell element nor- +mal by the angle MANGL. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotatingthe material axes about the element normal by +an angle, MANGL, from a line in the plane of the ele- +ment defined by the cross product of the vector v with +the element normal +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). +XP, YP, ZP +Coordinates of point 𝐩 for AOPT = 1. +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3. +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2. +MANGL +THICK +Material angle in degrees for AOPT = 0 and 3, may be overwritten +on the element card, see *ELEMENT_SHELL_BETA. +Balance thickness changes of the material due to the matrix +description by scaling fiber stresses +EQ.0: No scaling +EQ.1: Scaling +IDFi +ID for i-th fiber family for post-processing +ALPHi +Orientation angle 𝛼𝑖 for i-th fiber with respect to overall material +direction +EFi +Young’s modulus for i-th fiber family +VARIABLE +DESCRIPTION +LCEFi +G23_i +G31_i +Gij +LCGij +Curve ID for stress versus fiber elongation of i-th fiber. With this +option active, EFi is ignored. +Transversal shear modulus orthogonal to direction of fiber i +Transversal shear modulus in direction of fiber i +Linear shear modulus for shearing between fiber i and j +Curve ID for shear stress versus shearing between of i-th and j-th +fiber. With this option active, Gij is ignored. For details see +parameter METHij. +ALOCij +Locking angle (in radians) for shear between fiber families i and j +GLOCij +Linear shear modulus for shear angles larger than ALOCij +METHij +Option for shear between fiber i and j : +EQ.0: Elastic shear response, curve LCGij defines shear +stress vs. scalar product of fibers directions. +EQ.1 +Elasto-plastic shear response, curve LCGij defines yield +shear stress vs. normalized scalar product of fiber di- +rections. +EQ.2: Elastic shear response, curve LCGij defines shear +stress vs. shear angle between fibers given in rad. +EQ.3: Elasto-plastic shear response, curve LCGij defines yield +shear stress vs. normalized shear angle between fi- +bers. +EQ.4: Elastic shear response, curve LCGij defines shear +stress vs. shear angle between fibers given in rad. +This option is a special implementation for non- +crimped fabrics, where one of the fiber families corre- +sponds to a stitching. +EQ.5: Elasto-plastic shear response, curve LCGij defines yield +shear stress vs. normalized shear angle between fi- +bers. This option is a special implementation for non- +crimped fabrics, where one of the fiber families corre- +sponds to a stitching. +EQ.10: Elastic shear response, curve LCGij defines shear +stress vs. shear angle between fibers given in rad. +This option is tailored for woven fabrics and guaran- +tees a pure shear stress response. +*MAT_REINFORCED_THERMOPLASTIC +DESCRIPTION +EQ.11: Elasto-plastic shear response, curve LCGij defines +yield shear stress vs. normalized shear angle. This +option is tailored for woven fabrics and guarantees a +pure shear stress response +POSTV +Defines additional history variables that might be useful for post- +processing. See remarks below for details. +Stress calculation: +This material features an additive split of matrix and reinforcement contributions, i.e. +the combined stress response 𝝈 equals the sum 𝝈𝑚 + 𝝈𝑓 . The matrix mechanics is +described by an elasto-plastic material formulation with a von-Mises yield criterion. +The contribution of the reinforcement is formulated as a hyperelastic material. Based +0 is +on the orientation angel 𝛼𝑖 of the i-th fiber family an initial fiber direction 𝐦𝑖 +computed. By using the deformation gradient 𝐅 the current fiber configuration is +0 containing all necessary information on fiber strain and +defined as 𝐦i = 𝐅 𝐦𝑖 +reorientation. +Following standard textbook mechanics for anisotropic and hyperelastic materials, the +elastic stresses within the fibers due to tension or compression are given as +𝑓 = ∑ +𝑖=1 +where the function 𝑓𝑖 of the fiber stretch 𝜆𝑖 corresponds to the load curve LCEFi. +, +𝑓𝑖(𝜆𝑖)(𝐦i ⊗ 𝐦i) +𝝈𝑇 +The shear behavior of the reinforcement can be controlled by METHij. For values less +than 10, the behavior is again standard textbook mechanics: +𝝈𝑆 +𝑓 = ∑ +𝑖=1 +𝑔𝑖,𝑖+1(𝜅𝑖,𝑖+1)(𝐦i ⊗ 𝐦i+1) +Where 𝜅𝑖,𝑖+1 represents the employed shear measure (scalar product or shear angle in +rad). In general, the dyadic product 𝐦i ⊗ 𝐦i+1 does not define a shear stress tensor. +This might result in unphysical shear behavior in case of woven fabrics. Therefore, +𝑓 is always +METHij = 10 or 11 have been devised such that a pure shear stress tensor 𝝈𝑆 +obtained. +For even values of METHij, an elastic shear response is assumed. If defined, the load +curve LCGij corresponds to function 𝑔𝑖,𝑗. In this case the values of Gij, ALOCij and +GLOCij are ignored. +For odd values of METHij on the other hand, an elasto-plastic shear behavior is +assumed and the load curve LCGij defines the yield stress value as function of a +normalized shear parameter. This implies that the load curve has to be defined for +abscissa values between 0.0 and 1.0. A first elastic regime, which is controlled by the +linear shear stiffness Gij, is assumed until the yield stress given in the load curve for +normalized shear value 0.0 is reached. A second linear elastic regime is defined for +shear angles (𝜉𝑖𝑗)/ fiber angles (𝜂𝑖𝑗) larger than the locking angle ALOCij. The +corresponding stiffness in that regime is GLOCij. At the transition point to the second +elastic regime, the shear stress corresponds to the load curve value for a normalized +shear of 1.0. +History data: +This material formulation outputs additional data for post-processing to the set of +history variables if requested by the user. The parameter POSTV defines the data to be +written. Its value is calculated as +POSTV = a1 + 2 𝑎2 + 4 𝑎3 + 8 𝑎4 + 16 𝑎5 + 32 𝑎6. +Each flag 𝑎𝑖 is a binary (can be either 1 or 0) and corresponds to one particular post- +processing variable according to the following table. +Flag +Description +Variables +# hist +𝑎1 +𝑎2 +𝑎3 +𝑎4 +𝑎5 +𝑎6 +Fiber angle +Fiber ID +Fiber stretch +Fiber direction +𝜂12, 𝜂23 +IDF1, IDF2, IDF3 +𝜆1, 𝜆2, 𝜆3 +𝐦1, 𝐦2, 𝐦3 +Individual fiber stresses +𝑓1(𝜆1), 𝑓2(𝜆2), 𝑓3(𝜆3) +Fiber stress tensor +, 𝜎22 +, 𝜎33 +, 𝜎12 +, 𝜎23 +, +𝜎11 +𝜎31 +2 +3 +3 +9 +3 +6 +The above table also shows the order of output as well as the number of extra history +variables associated with the particular flag. In total NXH extra variables are required +depending on the choice of parameter POSTV. For example, the maximum number of +additional variables is NXH = 26 for POSTV = 63. +The post-processing data are written prior to most of the algorithmic history variables. +A list of potentially helpful history variables are given in the following table. +Position +Description +3 Number of Fibers +4 NXH +5→NXH+4 Extra post-processing output +NXH+5, NXH+6 +Shear angles 𝜉12and 𝜉23 +NXH+7 → NXH+12 Matrix stress tensor +NXH+13 → NXH+21 Deformation gradient +This is material type 249. It describes a material with unidirectional fiber reinforce- +ments and considers up to three distinguished fiber directions. Each fiber family is +described by a spatially transversely isotropic neo-Hookean constitutive law. The +implementation is based on an adapted version of the material described by Bonet and +Burton (1998). The material is only available for thin shell elements and in explicit +simulations. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +Variable +NFIB +AOPT +Type +I +F + Card 3 +Variable +1 +V1 +Type +F + Card 4 +1 +2 +V2 +F +2 +3 +EM +4 +PRM +F +F +3 +XP +F +3 +V3 +F +3 +4 +YP +F +4 +D1 +F +4 +Variable +IDF1 +ALPH1 +EF1 +KAP1 +Type +I +F +F +F +5 +G +F +5 +ZP +F +5 +D2 +F +5 +6 +7 +8 +EZDEF +F +6 +A1 +F +6 +7 +A2 +F +7 +D3 +MANGL +F +6 +F +7 +8 +A3 +F +8 +*MAT_249_UDFIBER *MAT_REINFORCED_THERMOPLASTIC_UDFIBER + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IDF2 +ALPH2 +EF2 +KAP2 +Type +I +F +F +F + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IDF3 +ALPH3 +EF3 +KAP3 +Type +I +F +F +F + VARIABLE +DESCRIPTION +MID +RO +EM +PR +G +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Density. +Isotropic young’s modulus 𝐸iso. +Poisson’s ratio 𝑣. +Linear shear modulus 𝐺fib. +EZDEF +Algorithmic parameter. If set to 1, last row of deformation +gradient is not updated during the calculation. +NFIB +Number of fiber families to be considered. +*MAT_REINFORCED_THERMOPLASTIC_UDFIBER *MAT_249_UDFIBER + VARIABLE +AOPT +DESCRIPTION +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element +with +nodes, +*DEFINE_COORDINATE_NODES, and then rotated +about the shell element normal by the angle MANGL. +as +EQ.2.0: globally orthotropic with material axes determined by +with +below, +vectors +defined +*DEFINE_COORDINATE_VECTOR. +as +EQ.3.0:: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, MANGL, from a line in the plane of the ele- +ment defined by the cross product of the vector v with +the element normal +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM +or +*DEFINE_COORDINATE_VECTOR). +XP, YP, ZP +Coordinates of point p for AOPT = 1. +A1, A2, A3 +Components of vector a for AOPT = 2. +V1, V2, V3 +Components of vector v for AOPT = 3. +D1, D2, D3 +Components of vector d for AOPT = 2. +MANGL +Material angle in degrees for AOPT = 0 and 3, may be overwritten +on the element card, see *ELEMENT_SHELL_BETA. +IDFi +ID for i-th fiber family for post-processing. +ALPHi +EFi +KAPi +Orientation angle 𝛼𝑖 for i-th fiber with respect to overall material +direction +Young’s modulus 𝐸𝑖 for i-th fiber family. +Fiber volume ratio 𝜅𝑖 of i-th fiber family. +*MAT_249_UDFIBER *MAT_REINFORCED_THERMOPLASTIC_UDFIBER +Stress calculation: +In this model up to three distinguished fiber families are considered. It is assumed that +there is no interaction between the families and, thus, that the resulting stress tensor is +given by the sum of the single fiber responses, each to be calculated as the sum of an +iso +isotropic and a spatially transversely isotropic neo-Hookean stress contribution, 𝝈𝑖 +tr , respectively. The implementation is based on the work of Bonet and Burton +and 𝝈𝑖 +(1998), adapted by BMW for simulation of unidirectional fabrics, see references below. +In order to determine the isotropic stress tensor 𝝈𝑖 +an isotropic bulk modulus 𝜆𝑖 have to be defined from the input values as: +𝑖𝑠𝑜, an isotropic shear modulus 𝜇 and +𝜇 = +𝐸iso +2(1 + 𝜈) + and 𝜆𝑖 = +𝐸iso(𝜈 + 𝑛𝑖𝜈2) +. +2(1 + 𝜈) +Here, the variable 𝑛𝑖 denotes the ratio between stiffness orthogonally to the fibers and in +fiber direction, i.e. 𝑛𝑖 = 𝐸iso/𝐸𝑖. Using the left Cauchy-Green tensor 𝒃 the isotropic neo- +Hookean model reads: +iso = +𝝈𝑖 +(𝒃 − 𝑰) + 𝜆𝑖(𝐽 − 1)𝑰. +0 is +Based on the orientation angel 𝛼𝑖 of the i-th fiber family an initial fiber direction 𝐦𝑖 +computed. The deformation gradient 𝐅 is used to define the current fiber configuration +0. This vector contains all necessary information on fiber elongation and +as 𝐦i = 𝐅 𝐦𝑖 +reorientation. +The spatially transversely isotropic neo-Hookean formulation is given by: +𝐽𝝈𝑖 +tr = 2𝛽𝑖(𝐼4 − 1)𝑰 + 2(𝛼 + 2𝛽𝑖ln𝐽 + 2𝛾𝑖(𝐼4 − 1))𝐦i ⊗ 𝐦i − 𝛼(𝒃𝐦i ⊗ 𝐦i + 𝐦i ⊗ 𝒃𝐦i) +with material parameters + 𝛼 = 𝜇 − 𝐺fib, +𝛽𝑖 = +𝐸iso𝜈2(1 − 𝑛𝑖) +4𝑚𝑖(1 + 𝜈) +, +𝑚𝑖 = 1 − 𝜈 − 2𝑛𝑖𝜈2, +𝛾𝑖 = +𝐸𝑖 𝜅𝑖(1 − 𝜈) +8𝑚 +− +𝜆𝑖 + 2𝜇 ++ +− 𝛽𝑖. +The parameter EZDEF activates a modification of the model. Instead of the standard +deformation gradient 𝐅, a modified tensor 𝐅̃ is employed to calculate current fiber +directions 𝐦i and left Cauchy-Green tensor 𝒃. In tensor 𝐅̃ only the first two rows of the +deformation gradient are updated based on the deformation of the element. This +*MAT_REINFORCED_THERMOPLASTIC_UDFIBER *MAT_249_UDFIBER +simplification can in some cases increase the stability of the model especially if the +structure undergoes large deformations. +References: +-Bonet, J., and A. J. Burton. "A simple orthotropic, transversely isotropic hyperelas- +tic constitutive equation for large strain computations." Computer methods in +applied mechanics and engineering 162.1 (1998): 151-164. +-Senner, T., et al. "A modular modeling approach for describing the in-plane +forming behavior of unidirectional non-crimp-fabrics." Production Engineering 8.5 +(2014): 635-643. +-Senner, T., et al. "Bending of unidirectional non-crimp-fabrics: experimental +characterization, constitutive modeling and application in finite element simula- +tion." Production Engineering 9.1 (2015): 1-10. + History data: +Position +Description +3 +4 +5 +ID of 1st fiber +ID of 2nd fiber +ID of 3rd fiber +6 → 8 Current direction of 1st fiber +9 → 11 Current direction of 2nd fiber +12 → 14 Current direction of 3rd fiber +15 Number of fibers +16 Projected orthogonal fiber strain (1st fiber) +17 Projected parallel fiber strain (1st fiber) +18 +Shear angle (1st fiber) in rad +19 Euler-Almansi strain (1st fiber) +20 Porosity (1st fiber) +21 +Fiber volume ratio (1st fiber) +22 Projected orthogonal fiber strain (2nd fiber) +23 Projected parallel fiber strain (2nd fiber) +24 +Shear angle (2nd fiber) in rad +25 Euler-Almansi strain (2nd fiber) +*MAT_249_UDFIBER *MAT_REINFORCED_THERMOPLASTIC_UDFIBER +26 Porosity (2nd fiber) +27 +Fiber volume ratio (2nd fiber) +28 Projected orthogonal fiber strain (3rd fiber) +29 Projected parallel fiber strain (3rd fiber) +30 +Shear angle (3rd fiber) in rad +31 Euler-Almansi strain (3rd fiber) +32 Porosity (3rd fiber) +33 +Fiber volume ratio (3rd fiber) +*MAT_251 +This is Material Type 251. It is similar to MAT_PIECEWISE_LINEAR_PLASTICITY +or MAT_024 , except for the 3-D table option that uses a +history variable (e.g. hardness, temperature, …) from a previous calculation to +evaluate the plastic behavior as a function of 1) history variable, 2) strain rate, and 3) +plastic strain. Only available for shell elements. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +6 +7 +8 +FAIL +TDEL +F +Default +none +none +none +none +10.E+20 + Card 2 +1 +2 +3 +4 +Variable +Type +Default + Card 3 +1 +2 +LCSS +F +0 +3 +4 +5 +VP +F +0 +5 +6 +7 +HISVN +PHASE +I +0 +6 +F +0 +7 +F +0 +8 +8 +Variable +EPS1 +EPS2 +EPS3 +EPS4 +EPS5 +EPS6 +EPS7 +EPS8 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ES1 +ES2 +ES3 +ES4 +ES5 +ES6 +ES7 +ES8 +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. +Poisson’s ratio. +FAIL +Failure flag. +LT.0.0: User defined failure subroutine, matusr_24 in dyn21.F, +is called to determine failure +EQ.0.0: Failure is not considered. This option is recommended +if failure is not of interest since many calculations will +be saved. +GT.0.0: Effective plastic strain to failure. When the plastic +strain reaches this value, the element is deleted from +the calculation. +TDEL +LCSS +Minimum time step size for automatic element deletion. +Load curve ID or Table ID . +Load curve for stress vs. plastic strain. 2-D table for stress vs. +plastic strain as a function of strain rates. 3-D table for stress vs. +plastic strain as a function of strain rates as a function of history +variable values . +VP +Formulation for rate effects: +EQ.0.0: Scale yield stress (default), +EQ.1.0: Viscoplastic formulation. +HISVN +Location of history variable in the history array of *INITIAL_- +STRESS_SHELL that is used to evaluate the 3-D table LCSS. +VARIABLE +PHASE +EPS1 - EPS8 +DESCRIPTION +Constant value to evaluate the 3-D table LCSS. Only used if +HISVN = 0. +Effective plastic strain values (optional). At least 2 points should +be defined. The first point must be zero corresponding to the +initial yield stress. +ES1 - ES8 +Corresponding yield stress values to EPS1 - EPS8. +Remarks: +If the 3-D table is used for LCSS, interpolation is used to find the corresponding +stress value for the current plastic strain, strain rate, and history variable. In +addition, extrapolation is used for the history variable evaluation, which means that +some upper and lower “limit curves” have to be used, if extrapolation is not desired. +If material history is written to dynain file using *INTERFACE_SPRINGBACK_LS- +DYNA, the history variable of material 251 (e.g. hardness, temperature, …) is +written to position HISV6 of *INITIAL_STRESS_SHELL. +It is recommended to set HISVN = 6 and to put the history variable on position +HISV6 if *MAT_251 is used in combination with *MAT_ADD_... +*MAT_TOUGHENED_ADHESIVE_POLYMER +This is Material Type 252, the Toughened Adhesive Polymer model (TAPO). It is based +on non-associated 𝐼1 - 𝐽2 plasticity constitutive equations and was specifically developed +to represent the mechanical behaviour of crash optimized high-strength adhesives +under combined shear and tensile loading. This model includes material softening due +to damage, rate-dependency, and a constitutive description for the mechanical +behaviour of bonded connections under compression. +A detailed description of this material can be found in Matzenmiller and Burbulla +[2013]. This material model can be used with solid elements or with cohesive elements +in combination with *MAT_ADD_COHESIVE. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +Variable +LCSS +TAU0 +Type +I + Card 3 +1 +F +2 +3 +E +F +3 +Q +F +3 +4 +PR +F +4 +B +F +4 +5 +6 +7 +8 +FLG +JCFL +DOPT +I +5 +H +F +5 +I +6 +C +F +6 +I +7 +8 +GAM0 +GAMM +F +7 +F +8 +Variable +A10 +A20 +A1H +A2H +A2S +POW +Type +F + Card 4 +1 +F +2 +Variable +Type +F +F +F +F +3 +D1 +F +4 +D2 +F +5 +D3 +F +6 +D4 +F +7 +8 +D1C +D2C +F +VARIABLE +DESCRIPTION +MID +RO +E +PR +FLG +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density 𝜌. +Young’s modulus 𝐸. +Poisson’s ratio 𝜈. +Flag to choose between yield functions 𝑓 and 𝑓 ̂, see Remarks. +EQ.0.0: Cap in tension. and Drucker & Prager in compression, +EQ.2.0: Cap in tension. and von Mises in compression. +JCFL +Johnson & Cook constitutive failure criterion flag, see Remarks. +EQ.0.0: use triaxiality factor only in tension, +EQ.1.0: use triaxiality factor in tension and compression. +DOPT +Damage criterion flag 𝐷̂ or 𝐷̌ , see Remarks. +EQ.0.0: damage model uses damage plastic strain 𝑟, +EQ.1.0: damage model uses plastic arc length 𝛾v. +LCSS +Curve ID or Table ID. +If LCSS is a curve ID: +The curve specifies yield stress 𝜏Y as a function of plastic +strain 𝑟. +If LCSS is a Table ID: +For each strain rate value the table specifies a curve ID +giving the yield stress versus plastic strain for that strain +rate or it defines for each tempera- +ture value a table ID which, in turn, maps strain rates to +curves giving the yield stress as a function of plastic strain +. +The yield stress versus plastic strain curve for the lowest +value of strain rate or temperature is used when the strain +rate or temperature falls below the minimum value. +Likewise, maximum values cannot be exceeded. Harden- +ing variables are ignored with this option (TAU0, Q, B, H, +C, GAM0, and GAMM). +*MAT_TOUGHENED_ADHESIVE_POLYMER +DESCRIPTION +TAU0 +Initial shear yield stress 𝜏0. +Q +B +H +C +Isotropic nonlinear hardening modulus 𝑞. +Isotropic exponential decay parameter 𝑏. +Isotropic linear hardening modulus 𝐻. +Strain rate coefficient 𝐶. +GAM0 +GAMM +Quasi-static threshold strain rate 𝛾0. +Maximum threshold strain rate 𝛾m. +Yield function parameter: initial value 𝑎10 of 𝑎1 = 𝑎 ̂1(𝑟). +Yield function parameter: initial value 𝑎20 of 𝑎2 = 𝑎 ̂2(𝑟). +Yield function parameter 𝑎1 +(ignored if FLG.EQ.2). +H for formative hardening +Yield function parameter 𝑎2 +(ignored if FLG.EQ.2). +H for formative hardening +Plastic potential parameter 𝑎2 +∗ for hydrostatic stress term. +Exponent 𝑛 of the phenomenological damage model. +Johnson & Cook failure parameter 𝑑1. +Johnson & Cook failure parameter 𝑑2. +Johnson & Cook failure parameter 𝑑3. +Johnson & Cook rate dependent failure parameter 𝑑4. +Johnson & Cook damage threshold parameter 𝑑1c. +Johnson & Cook damage threshold parameter 𝑑2c. +A10 +A20 +A1H +A2H +A2S +POW +D1 +D2 +D3 +D4 +D1C +D2C +Remarks: +Two different 𝐼1-𝐽2 yield criteria for isotropic plasticity can be defined by parameter +FLG: +Figure M252-1. Yield function 𝑓 and plastic flow potential 𝑓 ∗ +Figure M252-2. Yield function 𝑓 ̂ and plastic flow potential 𝑓 ∗ +1. FLG = 0 is used for the yield criterion 𝑓 which is changed at the case of +hydrostatic pressure 𝐼1 = 0 into the Drucker & Prager model (DP) +𝑓 ≔ +𝐽2 +(1 − 𝐷)2 + +√3 +𝑎1𝜏0 +𝐼1 +1 − 𝐷 ++ +𝑎2 +⟨ +𝐼1 +1 − 𝐷 +⟩ +− 𝜏Y +2 = 0 +with the Macauley bracket 〈∙〉, the first invariant of the stress tensor 𝐼1 = tr 𝛔, +and the second invariant of the stress deviator 𝐽2 = (1 2⁄ )tr(𝐬)2, see Figure +M252-1. +2. FLG = 2 is used for the yield criterion 𝑓 ̂ which is changed at the vertex into the +deviatoric von Mises yield function – see Figure M252-2 – and is used for con- +servative calculation in case of missing uniaxial compression or combined com- +pression and shear experiments: +𝑓 ̂ ≔ +𝐽2 +(1 − 𝐷)2 + +𝑎2 +⟨ +𝐼1 +1 − 𝐷 ++ +√3𝑎1𝜏0 +2𝑎2 +⟩ +− (𝜏Y +2 + +2𝜏0 +𝑎1 +4𝑎2 +) = 0 +The yield functions 𝑓 and 𝑓 ̂ are formulated in terms of the effective stress tensor + and the isotropic material damage 𝐷 according to the continuum +⁄ +𝛔̃ = 𝛔 (1 − 𝐷) +Figure M252-3. Accumulated plastic strain 𝛾v and damage plastic strain 𝑟 +versus strain 𝛾 +damage mechanics in Lemaitre [1992]. The stress tensor 𝛔 is defined in terms of the +elastic strain 𝛆e and the isotropic damage 𝐷: +𝛔 = (1 − 𝐷)ℂ𝛆e +The continuity (1 − 𝐷) in the elastic constitutive equation above degrades the fourth +order elastic stiffness tensor ℂ, +ℂ = 2𝐺 (𝕀 − +𝟏⨂𝟏) + 𝐾 𝟏⨂𝟏 +with shear modulus 𝐺, bulk modulus 𝐾, fourth order identity tensor 𝕀, and second +order identity tensor 𝟏. The plastic strain rate 𝛆̇p is given by the non-associated flow +rule +(1 − 𝐷)2 (𝐬 + +with the potential 𝑓 ∗ and an additional parameter 𝑎2 += +𝛆̇p = 𝜆 +𝜕𝑓 ∗ +𝜕𝛔 +∗〈𝐼1〉𝟏) +𝑎2 +∗ < 𝑎2 to reduce plastic dilatancy. +𝑓 ∗ ≔ +𝐽2 +(1 − 𝐷)2 + +∗ +𝑎2 +⟨ +𝐼1 +1 − 𝐷 +⟩ +2 +− 𝜏Y +The plastic arc length 𝛾̇v characterizes the inelastic response of the material and is +defined by the Euclidean norm: +𝛾̇v ≔ √2 tr(𝛆̇p)2 = +2𝜆 +(1 − 𝐷)2 +√𝐽2 + +(𝑎2 +∗〈𝐼1〉)2 +In addition, the arc length of the damage plastic strain rate 𝑟 ̇ is introduced by means of +the arc length 𝛾̇v and the continuity (1 − 𝐷) as in Lemaitre [1992], where 𝐼 ̃1 = 𝐼1 (1 − 𝐷) +and 𝐽 ̃2 = 𝐽2 (1 − 𝐷)2 +⁄ + are the effective stress invariants, see Figure M252-3. +⁄ +𝑟 ̇ ≔ (1 − D)𝛾̇v = 2λ√𝐽 ̃2 + +∗⟨𝐼 ̃1⟩) +(𝑎2 +The rate-dependent yield strength for shear 𝜏Y can be defined by two alternative +expressions. The first representation is an analytic expression for 𝜏Y: +𝜏Y = (𝜏0 + 𝑅) [1 + 𝐶 (⟨ln +𝛾̇ +𝛾̇0 +⟩ − ⟨ln +𝛾̇ +𝛾̇m +⟩)] , with 𝛾̇ = √2 tr(𝛆̇)2 +where the first factor (𝜏0 + 𝑅) in 𝜏Y is given by the static yield strength with the initial +yield 𝜏0 and the non-linear hardening contribution +𝑅 = 𝑞[1 − exp(−𝑏𝑟)] + 𝐻𝑟 +The second factor [… ] in 𝜏Y describes the rate dependency of the yield strength by a +modified Johnson & Cook approach with the reference strain rates 𝛾̇0 and 𝛾̇m which +Figure M252-4. Rate-dependent tensile strength 𝜏Y versus effective strain rate +𝛾̇ (left) and effective damage plastic strain 𝑟 (right) +limit the shear strength 𝜏Y, see Figure M252-4. +The second representation of the yield strength 𝜏Y is the table definition LCSS, where +hardening can be defined as a function of plastic strain, strain rate, and temperature. +Toughened structural adhesives show distortional hardening under plastic flow, i.e. +the yield surface changes its shape. This formative hardening can be phenomenological +described by simple evolution equations of parameters 𝑎1 = 𝑎 ̂1(𝑟) ∧ 𝑎2 = 𝑎 ̂2(𝑟) in the +yield criterions 𝑓 with the initial values 𝑎10 and 𝑎20: +H𝑟 ̇ +𝑎1 = 𝑎 ̂1(𝑟) ∧ 𝑎 ̇1 = 𝑎1 +𝑎2 = 𝑎 ̂2(𝑟) ∧ 𝑎2 ≥ 0 ∧ 𝑎 ̇2 = 𝑎2 +H𝑟 ̇ +H and 𝑎2 +H can take positive or negative values as long as the inequality +The parameters 𝑎1 +𝑎2 ≥ 0 is satisfied. The criterion 𝑎2 ≥ 0 ensures an elliptic yield surface. The yield +criterion 𝑓 ̂ uses only the initial values 𝑎1 = 𝑎10 and 𝑎2 = 𝑎20 without the distortional +hardening. +The empirical isotropic damage model 𝐷 is based on the approach in Lemaitre [1985]. +Two different evolution equations 𝐷̂̇ (𝑟, 𝑟 ̇) and 𝐷̌̇ (𝛾v, 𝛾̇v) are available, Figure M252-5 +see. The damage variable 𝐷 is formulated in terms of the damage plastic strain rate 𝑟 ̇ +(DOPT = 0) +𝐷̇ = 𝐷̂̇ (𝑟, 𝑟 ̇) = 𝑛 ⟨ +𝑛−1 +𝑟 − 𝛾c +𝛾f − 𝛾c +⟩ +𝑟 ̇ +𝛾f − 𝛾c +Figure M252-5. Influence of DOPT on damage softening +or of the plastic arc length 𝛾̇v (DOPT = 1) +𝐷̇ = 𝐷̌̇ (𝛾v, 𝛾̇v) = 𝑛 ⟨ +𝑛−1 +𝛾v − 𝛾c +𝛾f − 𝛾c +⟩ +𝛾̇v +𝛾f − 𝛾c +where r in contrast to 𝛾v increases non-proportionally slowly, see Figure M252-5. The +strains at the thresholds 𝛾c and 𝛾f for damage initiation and rupture are functions of the +triaxiality 𝑇 = 𝜎m 𝜎eq⁄ + with the hydrostatic stress 𝜎m = 𝐼1 3⁄ and the von Mises +equivalent stress 𝜎eq = √3𝐽2 as in Johnson and Cook [1985]. +𝛾c = [𝑑1c + 𝑑2cexp(−𝑑3〈𝑇〉)] (1 + 𝑑4 ⟨ln +⟩) +𝛾f = [𝑑1 + 𝑑2exp(−𝑑3〈𝑇〉)] (1 + 𝑑4 ⟨ln +⟩) +𝛾̇ +𝛾̇0 +𝛾̇ +𝛾̇0 +The option JCFL controls the influence of triaxiality 𝑇 = 𝜎m 𝜎eq⁄ + in the pressure range +for the thresholds 𝛾c and 𝛾f. JCFL = 0 makes use of the Macauley bracket 〈𝑇〉 for the +triaxiality 𝑇 = 𝜎m 𝜎eq⁄ + and JCFL = 1 omits the Macauley bracket 〈𝑇〉. +History Variables: + VARIABLE +DESCRIPTION +1 +2 +3 +4 +5 +6 +7 +damage variable 𝐷 +plastic arc length 𝛾v +effective strain rate +temperature +yield stress +damaged yield stress +triaxiality +*MAT_GENERALIZED_PHASE_CHANGE +This is Material Type 254. It is designed to model phase transformations in metallic +materials and the implied changes in the material properties. It is applicable to hot +stamping, heat treatment and welding processes and a wide range of steel alloys. It +accounts for up to 24 phases and provides a list of generic phase change mechanisms +for each possible phase changes. The parameters for the phase transformation laws are +to be given in tabulated form. +Given the current microstructure composition, the material formulation implements a +temperature and strain-rate dependent elastic-plastic material with non-linear +hardening behavior. Above a certain annealing temperature, the material behaves as +ideal elastic-plastic material with no evolution of plastic strains. +So far, the material has been implemented for solid and shell elements and is suitable +for explicit and implicit analysis. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +N +I +3 +4 +YM +F +4 +5 +PR +F +5 +6 +7 +8 +MIX +MIXR +I +6 +I +7 +8 +Variable +TASTRT +TAEND +CTE +DTEMP +TIME +Type +F + Card 3 +1 +F +2 +I +3 +4 +5 +6 +F +7 +F +8 +Variable +PTLAW +PTSTR +PTEND +PTX1 +PTX2 +PTX3 +PTX4 +PTX5 +Type +I +I +I +I +I +I +I +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PTTAB1 +PTTAB2 +PTTAB3 +PTTAB4 +PTTAB5 +Type + Card 5 +I +1 +I +2 +I +3 +I +4 +I +5 +6 +7 +8 +Variable +PTEPS +PTRIP +Type +I +F +GRAI +F +Phase Yield Stress Cards. For each of the N phases, one parameter SIGYi has to be +specified. A keyword card (with a “*” in column 1) terminates this input if less than 10 +cards are used. + Optional +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SIGY1 +SIGY2 +SIGY3 +SIGY4 +SIGY5 +SIGY6 +SIGY7 +SIGY8 +Type +I +I +I +I +I +I +I +I + VARIABLE +DESCRIPTION +MID +RO +N +YM +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density 𝜌. +Number of phases +Youngs’ modulus: +GT.0.0: constant value is used +LT.0.0: LCID or TABID. Temperature dependent Youngs’ +modulus given by load curve ID = -E or a Table +ID = -E. Use TABID to describe temperature de- +pendent modulus for each phase individually. +VARIABLE +DESCRIPTION +PR +Poisson’s modulus: +GT.0.0: constant value is used +LT.0.0: LCID or TABID. + Temperature dependent +Posson’s ratio given by load curve ID = -E or a Ta- +ble ID = -E. Use TABID to describe temperature +dependent parameter for each phase individually. +MIX +MIXR +Load curve ID with initial phase concentrations +LCID or TABID for mixture rule. Use a TABID to define a +temperature dependency +TASTART +TAEND +Annealing temperature start +Annealing temperature end +CTE +Coefficient of thermal expansion: +GT.0.0: constant value is used +LT.0.0: LCID or TABID. Temperature dependent CTE +given by load curve ID = -CTE or a Table ID = - +CTE. Use Table ID to describe temperature de- +pendent CTE for each phase individually. +DTEMP +TIME +Maximum temperature variation within a time step. If +exceeded during the analysis a local sub-cycling is used +Number of time units per hour. Default is seconds, that is +3600 time units per hour. +PTLAW +PTSTR +PTEND +PTXi +*MAT_GENERALIZED_PHASE_CHANGE +DESCRIPTION +Table ID to define phase transformation model as a function of +source phase and target phase. The values in *DEFINE_TABLE +are the phase numbers before transformation (source phase). The +curves referenced by the table specify transformation model +(ordinate) versus phase number after transformation (abscissa). +LT.0: Transformation model used in cooling +EQ.0: No transformation +GT.0: Transformation model is used in heating +There are four possible transformation models which can be +specified as ordinate values of the curves: +EQ.1: Koinstinen-Marburger +EQ.2: +JMAK +EQ.3: Akerstrom (only for cooling) +EQ.4: Oddy (only for heating) +Table ID to define start temperatures for the transformations as +function of source phase and target phase. The values in +*DEFINE_TABLE are the phase numbers before transformation +(source phase). The curves referenced by the table specify start +temperature (ordinate) versus phase number after transformation +(abscissa). +Table ID to define end temperatures for the transformations as +function of source phase and target phase. The values in +*DEFINE_TABLE are the phase numbers before transformation +(source phase). The curves referenced by the table specify end +temperature (ordinate) versus phase number after transformation +(abscissa). +Table ID defining the i-th scalar-valued phase transformation +parameter as function of source phase and target phase . The values in *DEFINE_TABLE are the phase +numbers before transformation (source phase). The curves +referenced by the table specify scalar parameter (ordinate) versus +phase number after transformation (abscissa). +VARIABLE +PTTABi +PTEPS +PTRIP +DESCRIPTION +i-th tabulated phase +Table ID of 3D table defining the +transformation parameter as function of source phase and target +phase . The values in *DEFINE_TABLE_3D +are the phase numbers before transformation (source phase). The +values in the 2D tables referenced by *DEFINE_TABLE_3D are +the phase number after transformation. The curves referenced by +the 2D tables specify tabulated parameter (ordinate) versus either +temperature or temperature rate (abscissa). +Table ID containing transformation induced strains as function of +source phase and target phase. +Flag for transformation induced plasticity (TRIP). Algorithm +active for positive value of PTRIP. +GRAIN +Initial grain size. +Remarks: +This material features temperature and phase composition dependent elastic plastic +behavior. The phase composition is determined using a list of generic phase +transformation mechanisms the user can choose from for each of the possible phase +transformations. So far, four different transformation models have been implemented +to describe the transition from source phase 𝑥a to target phase 𝑥b: +1. Koistinen-Marburger: +This formulation is tailored for non-diffusive transformations. The tempera- +ture dependent amount of the target phase is computed as +The factor 𝛼 is to be defined in table PTX1. +𝑥𝑏 = 𝑥𝑎(1.0 − 𝑒−𝛼(𝑇𝑠𝑡𝑎𝑟𝑡−𝑇)) +2. Generalized Johnson-Mehl-Avrami-Kolmogorov (JMAK): +This widely used model employs the evolution equation +𝑑𝑥𝑏 +𝑑𝑡 += 𝑛(𝑇)(𝑘𝑎𝑏𝑥𝑎 − 𝑘𝑎𝑏 +′ 𝑥𝑏) +for which the factors +⎜⎛ln ( +⎝ +𝑘𝑎𝑏(𝑥𝑎 + 𝑥𝑏) +′ 𝑥𝑏 +𝑘𝑎𝑏𝑥𝑎 − 𝑘𝑎𝑏 +) +⎟⎞ +⎠ +𝑛(𝑇)−1.0 +𝑛(𝑇) +𝑘𝑎𝑏 = +𝑥𝑒𝑞(𝑇) +𝜏(𝑇) +𝑓 (𝑇̇), 𝑘𝑎𝑏 +′ = +1.0 − 𝑥𝑒𝑞(𝑇) +𝜏(𝑇) +𝑓 ′(𝑇̇) +have to be defined. +As user input, load curve data for the exponent 𝑛(𝑇) in PTTAB1, the equilibri- +um concentration 𝑥𝑒𝑞(𝑇) in PTTAB2, the relaxation time 𝜏(𝑇) in PTTAB3, and +the temperature rate correction factors 𝑓 (𝑇̇) and 𝑓′(𝑇̇) in PTTAB4 and PTTAB5, +respectively, are expected. +3. Kirkaldy: +Similar to the implementation of *MAT_244, the transformation for cooling +phases can be computed by the evolution equation +𝑑𝑋𝑏 +𝑑𝑡 += 20.5(𝐺−1)𝑓 (𝐶)(𝑇𝑠𝑡𝑎𝑟𝑡 − 𝑇)𝑛𝑇𝐷(𝑇) +𝑋𝑏 +𝑛1(1.0−𝑋𝑏)(1.0 − 𝑋𝑏)𝑛2𝑋𝑏 +Y(𝑋𝑏) +𝑥𝑏 +. +𝑥𝑒𝑞(𝑇) +formulated in the normalized phase concentration 𝑋𝑏 = +In contrast to *MAT_244, the parameters for the evolution equation are not +determined from the chemical composition of the material but defined directly +as user input. The scalar data in PTX1 to PTX4 are interpreted as 𝑓 (𝐶), 𝑛𝑇, 𝑛1, +and 𝑛2. Tabulated data for 𝐷(𝑇), 𝑌(𝑋𝑏), and 𝑥𝑒𝑞(𝑇) are given in PTTAB1 to +PTTAB3. +4. Oddy: +For phase transformation in heating, the equation of Oddy can be used, which +can be interpreted as a simplified JAMK relation and reads +𝑑𝑥𝑏 +𝑑𝑡 += 𝑛 +𝑥𝑎 +𝑐1(𝑇 − 𝑇𝑠𝑡𝑎𝑟𝑡)−𝑐2 ⎝ +⎜⎛ln ( +(𝑥𝑎 + 𝑥𝑏) +𝑥𝑎 +⎟⎞ +) +⎠ +𝑛−1.0 +Its application requires the input of three scalar parameters 𝑛, 𝑐1, 𝑐2 that are read +from the respective positions in the tables in PTX1 to PTX3. +*MAT_PIECEWISE_LINEAR_PLASTIC_THERMAL +This is material type 255, an isotropic elastoplastic material with thermal properties. It +can be used for both explicit and implicit analyses. Young’s modulus and Poisson’s +ratio can depend on the temperature by defining two load curves. Moreover, the yield +stress in tension and compression are given as load curves for different temperatures by +using two tables. The thermal coefficient of expansion can be given as a constant +ALPHA or as a load curve, see LALPHA at position 3 on card 2. A positive curve ID for +LALPHA models the instantaneous thermal coefficient, whereas a negatives curve ID +models the thermal coefficient relative to a reference temperature, TREF. The strain rate +effects are modelled with the Cowper-Symonds rate model with the parameters C and P +on card 1. Failure can be based on effective plastic strain or using the *MAT_ADD_- +EROSION keyword. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +E +F +3 +Variable +TABIDC +TABIDT +LALPHA +Type +I + Card 3 +1 +I +2 +I +3 +Variable +ALPHA +TREF +Type +F +F +4 +PR +F +4 +4 +5 +C +F +5 +VP +F +5 +6 +P +F +6 +7 +8 +FAIL +TDEL +F +7 +F +8 +6 +7 +8 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +*MAT_PIECEWISE_LINEAR_PLASTIC_THERMAL +DESCRIPTION +E +Young’s modulus: +LT.0.0: E is given as a function of temperature, T. The curve +consists of (T,E) data pairs. Enter |E| on the DE- +FINE_CURVE keyword. +GT.0.0: E is constant. +PR +Poisson’s ratio. +LT.0.0: |PR| is the LCID for Poisson’s ratio versus tempera- +C +P +FAIL +TDEL +ture. +GT.0.0: PR is constant +Strain rate parameter. See Remark 1. +Strain rate parameter. See Remark 1. +Effective plastic strain when the material fails. User defined +failure subroutine, matusr_24 in dyn21.F, is called to determine +failure when FAIL < 0. Note that for solids the *MAT_ADD_- +EROSION can be used for additional failure criteria. +A time step less than TDEL is not allowed. A step size less than +TDEL trigger automatic element deletion. This option is ignored +for implicit analyses. +TABIDC +Table ID for yield stress in compression, see Remark 2. +TABIDT +Table ID for yield stress in tension, see Remark 2. +LALPHA +Load curve ID for thermal expansion coefficient as a function of +temperature. +GT.0.0: the instantaneous thermal expansion coefficient based +on the following formula: +𝑑𝜀𝑖𝑗 +thermal = 𝛼(𝑇)𝑑𝑇𝛿𝑖𝑗 +LT.0.0: the thermal coefficient is defined relative a reference +temperature TREF, such that the total thermal strain is +given by: +thermal = 𝛼(𝑇)(𝑇 − 𝑇ref)𝛿𝑖𝑗 +𝜀𝑖𝑗 +With this option active, ALPHA is ignored. +VARIABLE +DESCRIPTION +VP +Formulation for rate effects, see Remarks 1 and 2. +EQ.0.0: effective total strain rate (default) +NE.0.0: effective plastic strain rate +ALPHA +Coefficient of thermal expansion +TREF +Reference temperature, which is required if and only if LALPHA +is given with a negative load curve ID. +Remarks: +1. Strain Rate Effects. The strain rate effect is modelled by using the Cowper +and Symonds model which scales the yield stress according to the factor +1 + ( +𝜀̇eff +1 𝑃⁄ +) +where 𝜀̇eff = √tr(𝛆̇𝛆̇T) is the Euclidean norm of the total strain rate tensor if +𝑝 . +VP = 0 (default), otherwise 𝜀̇eff = 𝜀̇eff +2. Yield Stress Tables. The dependence of the yield stresses on the effective +plastic strains is given in two tables. +a) TABIDC gives the behaviour of the yield stresses in compression +b) TABIDT gives the behaviour of the yield stresses in tension. +The table indices consist of temperatures, and at each temperature a yield stress +curve must be defined. +Both TABIDC and TABIDT can be 3D tables, in which temperatures indexes the +main table and strain rates are defined as values for the sub tables with harden- +ing curves as targets for those strain rates. If the same yield stress should be +used in both tension and compression, only one table needs to be defined and +the same TABID is put in position 1 and 2 on card 2. If VP = 0, effective total +strain rates are used in the 3D tables, otherwise plastic strain rates. +3. History Variables. Two history variables are added to the d3plot file, the +Young’s modulus and the Poisson’s ratio, respectively. They can be requested +through the *DATABASE_EXTENT_BINARY keyword. +4. Nodal Temperatures. Nodal temperatures must be defined by using a +coupled analysis or some other way to define the temperatures, such as +*LOAD_THERMAL_VARIABLE or *LOAD_THERMAL_LOAD_CURVE. +*MAT_AMORPHOUS_SOLIDS_FINITE_STRAIN +This is material type 256, an isotropic elastic-viscoplastic material model intended to +describe the behaviour of amorphous solids such as polymeric glasses. The model +accurately captures the hardening-softening-hardening sequence and the Bauschinger +effect experimentally observed at tensile loading and unloading respectively. The +formulation is based on hyperelasticity and uses the multiplicative split of the +deformation gradient F which makes it naturally suitable for both large rotations and +large strains. Stress computations are performed in an intermediate configuration and +are therefore preceded by a pull-back and followed by a push-forward. The model was +originally developed by Anand and Gurtin [2003] and implemented for solid elements +by Bonnaud and Faleskog [2008] + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F + Card 2 +1 +Variable +ALPHA +Type +F +2 +H0 +F +3 +K +F +3 +SCV +F +4 +G +F +4 +B +F +5 +MR +F +5 +ECV +F +6 +LL +F +6 +G0 +F +7 +NU0 +F +7 +S0 +F +8 +M +F +8 + VARIABLE +DESCRIPTION +MID +RO +K +G +MR +LL +NU0 +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +Bulk modulus +Shear modulus +Kinematic hardening parameter: μR +Kinematic hardening parameter: λL +Creep parameter: ν0 +*MAT_AMORPHOUS_SOLIDS_FINITE_STRAIN +DESCRIPTION +M +ALPHA +Creep parameter: m +Creep parameter: α +Isotropic hardening parameter: h0 +Isotropic hardening parameter: scv +Isotropic hardening parameter: b +Isotropic hardening parameter: ηcv +Isotropic hardening parameter: g0 +Isotropic hardening parameter: s0 +H0 +SCV +B +ECV +G0 +S0 +Remarks: +1. Kinematic hardening gives rise to the second hardening occurrence in the +hardening-softening-hardening sequence. The constants μR and λL enter the +back stress μB (where B is the left Cauchy-Green deformation tensor) through +the function μ according to: +𝜇 = 𝜇𝑟 ( +𝜆𝐿 +3𝜆𝑝) 𝐿−1 ( +𝜆𝑝 +𝜆𝐿 +) +(256.1) +Where 𝜆𝑝 = 1 +√3 +√𝑡𝑟(𝐵𝑝) and 𝐵𝑝 is the plastic part of the left Cauchy-Green de- +formation tensor and where L is the Langevin function defined by, +𝐿(𝑋) = coth(𝑋) − 𝑋−1 +2. This material model assumes plastic incompressibility. Nevertheless in order to +account for the different behaviours in tension and compression a Drucker- +Prager law is included in the creep law according to: +𝜈𝑝 = 𝜈0 ( +𝜏̅ +𝑠 + 𝛼𝜋 +𝑚⁄ +) +(256.2) +Where 𝜈𝑝 is the equivalent plastic shear strain rate, +stress, s the internal variable defined below and -π the hydrostatic stress. +the equivalent shear +3. +Isotropic hardening gives rise to the first hardening occurrence in the harden- +ing-softening-hardening sequence. Two coupled internal variables are defined: +s the resistance to plastic flow and η the local free volume. Their evolution +equations read: +𝑠 ̇ = ℎ0 [1 − +𝑠 ̃(𝜂) +] 𝜈𝑝 +𝜂̇ = 𝑔0 ( +𝑠𝑐𝑣 +− 1) 𝜈𝑝 +𝑠 ̃(𝜂) = 𝑠𝑐𝑣[1 + 𝑏(𝜂𝑐𝑣 − 𝜂)] +(256.3) +(256.4) +(256.5) +4. Typical material parameters values are given in Ref.1 for Polycarbonate: + PolyC 1 +1 +Variable +MID +Value + PolyC 2 +1 +Variable +ALPHA +2 +RO +2 +H0 +3 +K +4 +G +5 +MR +6 +LL +7 +NU0 +8 +M +2.24GPa 0.857GPa 11.0MPa +1.45 +0.0017s-1 +0.011 +3 +SCV +4 +B +5 +ECV +6 +G0 +7 +S0 +8 +Value +0.08 +2.75GPa 24.0MPa +825 +0.001 +0.006 +20.0MPa +[1] Anand, L., Gurtin, M.E., 2003, “A theory of amorphous solids undergoing large +deformations, with application to polymeric glasses,” International Journal of Solids and +Structures, 40, pp. 1465-1487. +*MAT_STOUGHTON_NON_ASSOCIATED_FLOW +This is Material Type 260A. This material model is implemented based on non- +associated flow rule models (Stoughton 2002 and 2004). Strain rate sensitivity can be +included using a load curve. This model applies to both shell and solid elements. +Available options include: + +XUE +The option XUE is available for solid elements only. +Card 1 +1 +2 +Variable +MID +RO +Type +A8 +F +3 +E +F +4 +5 +6 +7 +8 +PR +R00 +R45 +R90 +SIG00 +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SIG45 +SIG90 +SIG_B +LCIDS +LCIDV +SCALE +Type +F +F +F +I +I +F +Default +none +none +none +none +none +1.0 +Define the following card only for the option XUE (available for solids only): +6 +7 +8 +Card 3 +1 +2 +Variable +EF0 +PLIM +Type +F +F +3 +Q +F +4 +GAMA +F +5 +M +F +Default +none +none +none +none +none +Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +AOPT +Type +F +Default +none +Card 4 +1 +Variable +XP +Type +F +2 +YP +F +3 +ZP +F +4 +A1 +F +5 +A2 +F +6 +A3 +F +7 +8 +Default +none +none +none +none +none +none +Card 5 +1 +Variable +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +5 +6 +7 +8 +D1 +D2 +D3 +F +F +F +Default +none +none +none +none +none +none + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s Modulus +Poisson’s ratio +R00, R45, +R90 +Lankford parameters in rolling (0°), diagonal (45°) and transverse +(90°) directions, respectively; determined from experiments. +SIG00, +SIG45, +SIG90, SIG_B +SIG00: the initial yield stress from uniaxial tension tests in rolling +(0°) direction; +SIG45: the initial yield stress from uniaxial tension tests in +diagonal (45°) direction; +SIG90: the initial yield stress from uniaxial tension tests in +transverse (90°) directions; +SIG_B: the initial yield stress from equi-biaxial stretching tests. +LCIDS +ID of a load curve defining stress vs. strain hardening behavior +from a uniaxial tension test along the rolling direction. +VARIABLE +LCIDV +SCALE +DESCRIPTION +ID of a load curve defining stress scale factors vs. strain rates; +determined from experiments. An example of the curve can be +found in Figure M260A-2. Furthermore, strain rates are stored in +history variable #5. Strain rate scale factors are stored in history +variable #6. To turn on the variables for viewing in LS-PrePost, set +NEIPS to at least “6” in *DATABASE_EXTENT_BINARY. It is +very useful to know what levels of strain rates, and strain rate +scale factors in a particular simulation. Once d3plot files are +opened in LS-PrePost, individual element time history can be +plotted via menu option Post → History, or a color contour of the +entire part can be viewed with the menu option Post → FriComp +→ Misc. +This variable can be used to speed up the simulation while +equalizing the strain rate effect, useful especially in cases where +the pulling speed or punch speed is slow. For example, if the +pulling speed is at 15 mm/s but running the simulation at this +speed will take a long time, the pulling speed can be increased to +500 mm/s while "SCALE" can be set to 0.03, giving the same +results as those from 15 mm/s, but with the benefit of greatly +reduced computational time, see Figures M260A-3 and M260A-4. +Note the increased absolute value (within a reasonable range) of +mass scaling -1.0*dt2ms frequently used in forming simulation +does not affect the strain rates, as shown in the Figure M260A-5. +EF0, PLIM, +Q, GAMA, +M +Material parameters for the option XUE. The parameter k in the +original paper is assumed to be 1.0. For details, refer to Xue, L., +Wierzbicki, T.’s 2009 paper “Numerical simulation of fracture mode +transition in ductile plates” in the International Journal of Solids and +Structures. +AOPT +*MAT_STOUGHTON_NON_ASSOCIATED_FLOW +DESCRIPTION +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the shell ele- +ment normal by the angle BETA. +EQ.1.0: locally orthotropic with material axes determined by +the point 𝐩 in space and the global location of the ele- +ment center; this is the 𝐚-direction. This option is for +solid elements only. +EQ.2.0: globally orthotropic with material axes determined by +the vector 𝐚 for shells and by both vectors 𝐚 and 𝐝 for +solids, as with *DEFINE_COORDINATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector 𝐯 with the +element normal. The plane of a solid element is the +mid-surface between the inner surface and outer sur- +face defined by the first four nodes and the last four +nodes of the connectivity of the element, respectively. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE__CO- +ORDINATE_VECTOR). +XP, YP, ZP +Coordinates of point 𝐩 for AOPT = 1. +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2, for shells and solids. +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3. +D1, D2, D3 +Components of vector 𝐝 for AOPT = 2, for solids. +The Stoughton non-associated flow rule: +In non-associated flow rule, material yield function does not equal to the plastic flow +potential. According to Thomas B. Stoughton’s paper titled “A non-associated flow rule +for sheet metal forming” in 2002 International Journal of Plasticity 18, 687-714, and “A +pressure-sensitive yield criterion under a non-associated flow rule for sheet metal forming” in +2004 International Journal of Plasticity 20, 705-731, plastic potential is defined by: +𝜎̅̅̅̅̅𝑝 = √𝜎11 +2 + 𝜆𝑝𝜎22 +2 − 2𝜈𝑝𝜎11𝜎22 + 2𝜌𝑝𝜎12 +where 𝜎𝑖𝑗 is the stress tensor component; where also, +𝜆𝑝 = +1 + 1 +𝑟90 +1 + 1 +𝑟0 +, +, +𝜈𝑝 = +𝑟0 +1 + 𝑟0 ++ 1 +𝑟0 +𝑟90 +1 + 1 +𝑟0 +where 𝑟0, 𝑟45, 𝑟90 are Lankford parameters in the rolling (0°), the diagonal (45°) and the +transverse (90°) directions, respectively. ++ 𝑟45). +𝜌𝑝 = +( +Yield function is defined by: +𝜎̅̅̅̅̅𝑦 = √𝜎11 +2 + 𝜆𝑦𝜎22 +2 − 2𝜈𝑦𝜎11𝜎22 + 2𝜌𝑦𝜎12 +where, +𝜆𝑦 = ( +𝜎0 +𝜎90 +) +, +𝜈𝑦 = +𝜌𝑦 = +[1 + 𝜆𝑦 − ( +) +𝜎0 +𝜎𝑏 +] , +[( +) +2𝜎0 +𝜎45 +− ( +𝜎0 +𝜎𝑏 +) +]. +where 𝜎0, 𝜎45, 𝜎90 are the initial yield stresses from uniaxial tension tests in the rolling +(0°), the diagonal (45°), and the transverse (90°) directions, respectively. 𝜎𝑏 is the initial +yield stress from an equi-biaxial stretching test. +The required stress-strain hardening curve must be for uniaxial tension along the +rolling direction. Strain rate sensitivity is implemented as an option, by defining a +curve (LCIDV) of strain rates vs. stress scale factors, see Figure M260A-2. +The variable SCALE is very useful in speeding up the simulation while equalizing the +strain rate effect. For example, if the real, physical pulling speed is at 15 mm/s but +running at this speed will take a long time, one could increase the pulling speed to 500 +mm/s while setting the SCALE to 0.03, resulting in the same results as those from 15 +mm/s with the benefit of greatly reduced computational time. See examples in +Verification. +History variables: +1. Strain rates: history variable #5. +2. Strain rate scale factors: history variable #6. +Verification: +Uniaxial tension tests were done on a single shell element as shown in Figure M260A-1. +Strain rate effect LCIDV is input as shown in Figure M260A-2. In Figure M260A-3, +pulling stress vs. strain from various test conditions are compared with input stress- +strain curve A. In summary, using the parameter SCALE, the element can be pulled +much faster (500 mm/s vs. 15 mm/s) but achieve the same stress vs. strain results, the +same strain rates (history variable #5), and the same strain rate scale factor (history +variable #6 in Figure M260A-4). Simulation speed can be improved further with +increased mass scaling (-1.0*dt2ms) without affecting the results, see Figure M260A-5. +A partial keyword input is provided below, for the case with pulling speed of 500 +mm/s, strain hardening curve ID of 100, LCIDV curve ID of 105, and strain rate scale +factor of 0.03. +*KEYWORD +*parameter_expression +R endtime 0.012 +R v 500.0 +*CONTROL_TERMINATION +$ ENDTIM ENDCYC DTMIN ENDNEG ENDMAS +&endtime +*MAT_STOUGHTON_NON_ASSOCIATED_FLOW +$# mid Ro E PR R00 R45 R90 SIG00 + 1 7.8000E-9 2.10E05 0.300000 1.1 1.2 1.3 150.4 +$ SIG45 SIG90 SIG_B LCIDS LCIDV SCALE + 150.1 150.2 150.30 100 105 0.03 +$ AOPT + 3 +$ XP YP ZP A1 A2 A3 +$ V1 V2 V3 D1 D2 D3 BETA + 1.0 +*DEFINE_CURVE + 100 + 0.00000E+00 0.30130E+03 + 0.10000E-01 0.42295E+03 + 0.20000E-01 0.47991E+03 + 0.30000E-01 0.52022E+03 + 0.40000E-01 0.55126E+03 + 0.50000E-01 0.57615E+03 +⋮ +*DEFINE_CURVE +2-1298 (MAT_248) +105 + 0.00000E+00 0.10000E+01 + 0.10000E+00 0.10608E+01 + 0.50000E+00 0.10828E+01 + 0.10000E+01 0.10923E+01 +*END +⋮ +⋮ +Revision information: +This material model is available starting in Revision 101821 in explicit, SMP only. The +option XUE is available starting on Revision 112711. +Fy +0= +n i- a +x i a l str e s s +Fy +0= +n str a i n +e ll + s h +Figure M260A-1. Uniaxial tension tests on a single shell element. +1.2 +1.15 +1.1 +1.05 +1.0 +0.0 +LCIDV +1.5 +2.0 +0.5 +1.0 +Strain rate (x103) +Figure M260A-2. Input LCIDV. +1000 +800 +600 +400 +200 +) +( +Input +Pull speed: 15 mm/s, +no LCIDV, SCALE=1.0 +Pull speed: 15 mm/s, +LCIDV, SCALE=1.0 +Pull speed: 500 mm/s, +LCIDV, SCALE=1.0 +Pull speed: 500 mm/s, +LCIDV, SCALE=0.03 +0.0 +0.2 +0.4 +0.6 +0.8 +1.0 +Strain +) +/ +( +- +# +3.5 +3.0 +2.5 +2.0 +1.5 +1.0 +0.5 +0.0 +0.03 +0.06 +0.09 +Pull speed: 15 mm/s, +LCIDV, SCALE=1.0 +Pull speed: 500 mm/s, +LCIDV, SCALE=1.0 +Pull speed: 500 mm/s, +LCIDV, SCALE=0.03 +0.1 +0.2 +Time (sec) +0.3 +0.012 +100 +86 +72 +58 +44 +30 +15 +0.4 +Figure M260A-3. Recovered stress-strain curve (top) and strain rates (bottom) +under various conditions shown. +1.12 +1.1 +1.08 +1.06 +1.04 +1.02 +- +# +1.00 +0.0 +0.03 +0.06 +0.09 +0.012 +1.16 +Pull speed: 15 mm/s, +LCIDV, SCALE=1.0 +Pull speed: 500 mm/s, +LCIDV, SCALE=1.0 +Pull speed: 500 mm/s, +LCIDV, SCALE=0.03 +0.1 +0.2 +Time (sec) +0.3 +1.13 +1.11 +1.08 +1.05 +1.03 +1.00 +0.4 +Figure M260A-4. Recovered strain rate scale factors under various conditions +shown. +1000 +800 +600 +400 +200 +) +( +Input +Pull speed: 500 mm/s, +LCIDV, SCALE=0.03, DT2MS=0.0 +Pull speed: 500 mm/s, +LCIDV, SCALE=0.03, DT2MS=-4E-6 +0.0 +0.2 +0.4 +0.6 +0.8 +1.0 +Figure M260A-5. Effect of mass scaling (-1.0*dt2ms). +Strain +*MAT_MOHR_NON_ASSOCIATED_FLOW_{OPTION} +This is Material Type 260B. This material model is implemented based on the papers by +Mohr, D., et al.(2010) and Roth, C.C., Mohr, D. (2014). The Johnson-Cook plasticity +model of strain hardening, strain rate hardening, and temperature soften effect is +modified with a mixed Swift-Voce strain hardening function, coupled with a non- +associated flow rule which accounts for the difference between directional dependency +of the 𝑟-values (planar anisotropic), and planar isotropic material response of certain +Advanced High Strength Steels (AHSS). A ductile fracture model is included based on +Hosford-Coulomb fracture initiation model. This model applies to shell elements only. +Available options include: + +XUE +Card 1 +1 +2 +Variable +MID +RO +Type +A8 +F +3 +E +F +4 +5 +6 +7 +8 +PR +P12 +P22 +P33 +G12 +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +G22 +G33 +LCIDS +LCIDV +LCIDT +LFLD +LFRAC +W0 +Type +F +F +I +I +I +Default +none +none +none +none +none +I +0 +I +F +none +none +Card 3 +Variable +Type +1 +A +F +2 +3 +B0 +GAMMA +F +F +4 +C +F +5 +N +F +6 +7 +8 +SCALE +SIZE0 +F +F +Default +none +none +none +none +none +1.0 +none +Card 4 +1 +2 +Variable +TREF +TMELT +Type +F +F +3 +M +F +4 +5 +6 +7 +8 +ETA +CP +TINI +DEPSO +DEPSAD +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +Define the following card only for the option XUE: +Card 5 +1 +2 +Variable +EF0 +PLIM +Type +F +F +3 +Q +F +4 +GAMA +F +5 +M +F +Default +none +none +none +none +none +6 +7 +Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +AOPT +Type +F +Default +none +Card 6 +1 +2 +3 +Variable +Type +Default +Card 7 +1 +Variable +V1 +Type +F +2 +V2 +F +3 +V3 +F +Default +none +none +none +7 +8 +4 +A1 +F +5 +A2 +F +6 +A3 +F +none +none +none +4 +5 +6 +7 +8 + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s Modulus +Poisson’s ratio +P12, P22, P33 +G12, G22, +G33 +LCIDS +LCIDV +LCIDT +LFLD +LFRAC +*MAT_MOHR_NON_ASSOCIATED_FLOW +DESCRIPTION +Yield function parameters, defined by Lankford parameters in +rolling (0°), diagonal (45°) and transverse (90°) directions, +respectively; see Non-associated flow rule. +Plastic +flow potential parameters, defined by Lankford +parameters in rolling (0°), diagonal (45°) and transverse (90°) +directions, respectively; see Non-associated flow rule. +Load curve ID defining stress vs. strain hardening behavior from +a uniaxial tension test; must be along the rolling direction. Also +see A modified Johnson-Cook. +Load curve ID defining stress scale factors vs. strain rates (Figure +M260B-1 middle); determined from experiments. Strain rates are +stored in history variable #5. Strain rate scale factors are stored in +history variable #6. To turn on the variables for viewing in LS- +PrePost, set NEIPS to at least “6” in *DATABASE_EXTENT_BI- +NARY. It is very useful to know what levels of strain rates, and +strain rate scale factors in a particular simulation. Once d3plot +files are opened in LS-PrePost, individual element time history can +be plotted via menu option Post → History, or a color contour of +the entire part can be viewed with the menu option Post → +FriComp → Misc. Also see A modified Johnson-Cook. +Load curve ID defining stress scale factors vs. temperature in +Kelvin (Figure M260B-1 bottom); determined from experiments. +Temperatures are stored in history variable #4. Temperature +scale factors are stored in history variable #7. To turn on this +variable for viewing in LS-PrePost, set NEIPS to at least “7” in +*DATABASE_EXTENT_BINARY. It is very useful to know what +levels of temperatures and temperature scale factors in a +particular simulation. Once d3plot files are opened in LS-PrePost, +individual element time history can be plotted via menu option +Post → History, or a color contour of the entire part can be viewed +with the menu option Post → FriComp → Misc. Also see A +modified Johnson-Cook. +Load curve ID defining traditional Forming Limit Diagram for +linear strain paths. +Load curve ID defining a fracture limit curve. Leave this field +empty if parameters A, B0, GAMMA, C, N are defined. However, +if this field is defined, parameters A, B0, GAMMA, C, N will be +ignored even if they are defined. +VARIABLE +DESCRIPTION +W0 +Neck (FLD failure) width, typically is the blank thickness. +A, B0, +GAMMA, C, +N +SCALE +Material parameters for the rate-dependent Hosford-Coulomb +fracture initiation model, see Rate-dependent Hosford-Coulomb. +This variable can be used to speed up the simulation while +equalizing the strain rate effect, useful especially in cases where +the pulling speed or punch speed is slow. For example, if the +pulling speed is at 15 mm/s but running the simulation at this +speed will take a long time, the pulling speed can be increased to +500 mm/s while "SCALE" can be set to 0.03, giving the same +results as those from 15 mm/s, but with the benefit of greatly +reduced computational time, see examples and Figures in +*MAT_260A for details. Furthermore, the increased absolute +value (within a reasonable range) of mass scaling -1.0*dt2ms +frequently used in forming simulation does not affect the strain +rates, as shown in the examples and Figures in *MAT_260A. +SIZE0 +Fracture gage length used in an experimental measurement, +typically between 0.2~0.5mm. +TREF, +TMELT, M, +ETA, CP, +TINI, DEPS0, +DEPSAD +EF0, PLIM, +Q, GAMA, +M +Material parameters +to +strain +temperature. TINI is the initial temperature. See A modified +Johnson-Cook for other parameters’ definitions. +softening effect due +for +Material parameters for the option XUE. The parameter k in the +original paper is assumed to be 1.0. For details, refer to Xue, L., +Wierzbicki, T.’s 2009 paper “Numerical simulation of fracture mode +transition in ductile plates” in the International Journal of Solids and +Structures. +AOPT +*MAT_MOHR_NON_ASSOCIATED_FLOW +DESCRIPTION +Material axes option : +EQ.0.0: +EQ.2.0: +EQ.3.0: +LT.0.0: +locally orthotropic with material axes determined +by element nodes 1, 2, and 4, as with *DEFINE_- +COORDINATE_NODES, and then rotated about +the shell element normal by the angle BETA. +globally orthotropic with material axes determined +by the vector 𝐚 for shells, as with *DEFINE_COOR- +DINATE_VECTOR. +locally orthotropic material axes determined by +rotating the material axes about the element nor- +mal by an angle, BETA, from a line in the plane of +the element defined by the cross product of the +vector 𝐯 with the element normal. +the absolute value of AOPT is a coordinate system +ID number (CID on *DEFINE_COORDINATE_- +NODES, +*DEFINE_COORDINATE_SYSTEM or +*DEFINE__COORDINATE_VECTOR). +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3. +Non-associated flow rule: +Referring to Mohr, D., Dunand, M., and Kim, K-H.’s 2010 and 2014 papers in the +International Journal of Plasticity, Hill’s 1948 quadratic yield function is written as: +where 𝝈 is the Cauchy stress tensor and 𝝈 the equivalent stress is defined by: +𝑓 (𝝈, 𝑘) = 𝜎̅̅̅̅̅ − 𝑘 = 0 +𝜎̅̅̅̅̅ = √(𝐏𝝈) ∙ 𝝈 +Where 𝐏 is a symmetric positive-definite matrix defined through three independent +parameters P12, P22, P33: +𝐏 = +P12 +⎡ +P12 P22 +⎢ +⎣ +⎤ +⎥ +P33⎦ +Flow rule, which defines the incremental plastic strain tensor, is written as follows: +𝑑𝛆𝑝 = 𝑑𝛿 +𝜕𝑔(𝝈) +𝜕𝝈 +where 𝑑𝛿 is a scalar plastic multiplier. The plastic potential function 𝑔(𝝈) can be +defined as a quadratic function in stress space: +with, +𝑔(𝝈) = √(𝐆𝝈) ∙ 𝝈 +𝐆 = +G12 +G12 G22 +⎡ +⎢ +⎣ +⎤ +⎥ +G33⎦ +When 𝐏𝐆, it leads to non-associated flow rule. For example, 𝐏 can represent isotropic +von-Mises yield surface by setting P11 = P22 = 1.0, P12 = −0.5, P33 = 3.0. 𝐆 can +represent an orthotropic plastic flow potential by setting: +𝐺12 = +𝐺22 = +𝐺33 = +, +𝑟0 +1 + 𝑟0 +𝑟0(1 + 𝑟90) +𝑟90(1 + 𝑟0) +(1 + 2𝑟45)(𝑟0 + 𝑟90) +𝑟90(1 + 𝑟0) +, +. +where 𝑟0, 𝑟45, 𝑟90 are Lankford coefficients in the rolling, diagonal and transverse +direction. Experiments have shown on the stress level, some AHSS, e.g., DP590, and +TRIP780 show strong directional dependency of 𝑟-values, while nearly the same stress- +strain curves have been measured in all directions. The directional dependency of 𝑟- +values suggests planar anisotropy while the material response on the stress level is +planar isotropic, which is the main reason to employ the non-associated flow rule. +On the other hand, if 𝐏 = 𝐆, the associated flow rule is recovered. +A modified Johnson-Cook plasticity model with mixed Swift-Voce hardening: +The Johnson-Cook plasticity model (1983) multiplicatively decomposes the deformation +resistance into three functions representing the effect of strain hardening, strain rate and +temperature. The Johnson-Cook model is modified to include hardening saturation +with a mixed Swift-Voce hardening law (Sung et al, A plastic constitutive equation +incorporating strain, strain-rate, and temperature, International Journal of Plasticity, 2010), +which gives a better description of the hardening at large strain levels, thus improving +the prediction of the necking and post-necking response of metal sheet: +𝜎𝑦 = (𝛼(𝐴(𝜀̅𝑝𝑙 + 𝜀0) +) + (1 − 𝛼) (𝑘0 + 𝑄(1 − 𝑒−𝛽𝜀̅𝑝𝑙))) +1 + 𝐶𝑙𝑛 +⎜⎜⎜⎛ +⎝ + 𝜀̇𝑝𝑙 +⎟⎞ +𝜀0̇ ⎠ +⎜⎛ +⎝ +⎟⎟⎟⎞ +⎠ +(1 +− ( +𝑇 − 𝑇𝑟 +𝑇𝑚 − 𝑇𝑟 +) +) +where 𝜀̅𝑝𝑙 and 𝜀̇𝑝𝑙 are effective plastic strain and strain rate, respectively; 𝑇𝑚 (TMELT), 𝑇𝑟 +(TREF) and 𝑇 are the melting temperature, reference temperature (ambient temperature +293 kelvin) and current temperature, respectively; 𝑚 (M) is an exponent coefficient. For +other symbols’ definitions refer to the aforementioned paper. +To make this material model more general and flexible, three load curves are used to +define the three components of the deformation resistance. A load curve (LCIDS) is +used to describe the strain hardening: +LCIDS: (𝛼(𝐴(𝜀̅𝑝𝑙 + 𝜀0) +) + (1 − 𝛼) (𝑘0 + 𝑄(1 − 𝑒−𝛽𝜀̅𝑝𝑙))) +Strain rate is described by a load curve LCIDV (stress scale factor vs. strain rates, +Figure M260B-1 middle), which scales the stresses based on the strain rates during a +simulation: +LCIDV: (1 + 𝐶𝑙𝑛 ( +𝑝𝑙 + 𝜀̇ +𝜀0̇ )) +The temperature softening effect is defined by another load curve LCIDT (stress scale +factor vs. temperature, Figure M260B-1 bottom), which scales the stresses based on the +temperatures during the simulation: +LCIDT: (1 − ( +𝑇−𝑇𝑟 +𝑇𝑚−𝑇𝑟 +) +) +The temperature effect is a self-contained model, in other words, it does not require +thermal exchange with the environment, and it calculates temperatures based on plastic +strain and strain rate. +The temperature evolution is determined with: +𝜂𝑘 +𝜌𝐶𝑝 +𝑑𝑇 = 𝜔[𝜀̇𝑝𝑙] +𝜎̅̅̅̅̅𝑑𝜀̅𝑝𝑙 +Where 𝜂𝑘 (ETA) is Taylor-Quinney coefficient, 𝜌 (R0) is the mass density and 𝐶𝑝 (CP) is +the heat capacity; also where, +𝜔[𝜀̇𝑝𝑙] = +(𝜀̇ +⎧ +{{{{ +{{{{ +⎨ +⎩ +𝑓𝑜𝑟 𝜀̇𝑝𝑙 < 𝜀̇𝑖𝑡 +𝑝𝑙−𝜀̇𝑖𝑡) +(3𝜀̇𝑎−2𝜀̇ +(𝜀̇𝑎−𝜀̇𝑖𝑡)3 +𝑝𝑙−𝜀̇𝑖𝑡) +𝑓𝑜𝑟 𝜀̇𝑖𝑡 ≤ 𝜀̇𝑝𝑙 ≤ 𝜀̇𝑎 +𝑓𝑜𝑟 𝜀̇𝑎 < 𝜀̇𝑝𝑙 +where 𝜀̇𝑖𝑡 > 0 and 𝜀̇𝑎 > 𝜀̇𝑖𝑡 define the limits of the respective domains of isothermal and +adiabatic conditions (𝜀̇𝑎 = DEPSAD). For simplification, 𝜀̇𝑖𝑡 = 𝜀̇0(DEPS0). +As shown in a single shell element uniaxial stretching (Figure M260B-1), the general +effect of the LCIDV is to elevate the strain hardening behavior as the strain rate +increases (curve “D” in Figure M260B-2 top), while the effect of the LCIDT is strain +softening as temperature rises (curve “C” in Figure M260B-2 top). A combined effect of +both LCIDV and LCIDT may result in strain hardening initially before temperature rise +enough to cause the strain softening in the model (curve “E” in Figure M260B-2 top). +The temperature and strain rates calculated for each element can be viewed with history +variables #4 and #5 (curves “C” and “D” in Figure M260B-2 bottom), respectively, while +the strain rate scale factors and temperature scale factors can be viewed with history +variable #6 and #7, respectively. +Rate-dependent Hosford-Coulomb fracture initiation model: +An extension of the Hosford-Coulomb fracture initiation model is used to account for +the effect of strain rate on ductile fracture. The damage accumulation is calculated +through history variable #3, and fracture occurs at an equivalent plastic strain 𝜀̅𝑓 when +the variable reaches 1.0: +𝜀𝑓 +∫ +𝑑𝜀̅𝑝𝑙 +𝑝𝑟[𝜂, 𝜃̅] +𝜀̅𝑓 + = 1 +𝑝𝑟, 𝜂, 𝜃̅ are strain to fracture, stress triaxiality and the Lode parameter, +Where 𝜀̅𝑓 +respectively. +The fracture parameters A, B0, GAMMA, C, N (𝑎, 𝑏0, 𝛾, 𝑐, 𝑛) are indicated in the +following equations. Strain to fracture for proportional load: +𝑝𝑟[𝜂, 𝜃̅] = 𝑏(1 + 𝑐) +𝜀̅𝑓 +{ +⎜⎜⎜⎜⎜⎛ +⎝ +((𝑓1 − 𝑓2)𝑎 + (𝑓2 − 𝑓3)𝑎 + (𝑓1 − 𝑓3)𝑎)} ++ 𝑐(2𝜂 + 𝑓1 + 𝑓3) +−1 +⎟⎟⎟⎟⎟⎞ +⎠ +where 𝑎 is the Hosford exponent, 𝑐 is the friction coefficient controlling the effect of +triaxiality, 𝑛 is the stress state sensitivity. +The Lode angle parameter dependent trigonometric functions: +𝑓1[𝜃̅] = 2 +3 cos[𝜋 +and coefficient 𝑏 (strain to fracture for uniaxial or equi-biaxial stretching): +6 (3 + 𝜃̅)], 𝑓3[𝜃̅] = − 2 +6 (1 − 𝜃̅)], 𝑓2[𝜃̅] = 2 +3 cos[𝜋 +3 cos[𝜋 +6 (1 + 𝜃̅)] +𝑏 = +{⎧ +⎩{⎨ +𝑏0 +𝑏0 (1 + 𝛾𝑙𝑛 [ +𝜀̇𝑝 +𝜀̇0 +]) +𝑓𝑜𝑟 𝜀̇𝑝 < 𝜀̇0 +𝑓𝑜𝑟 𝜀̇𝑝 > 𝜀̇0 +where 𝛾 is the strain rate sensitivity. +Corresponding parameters summary: +The following table lists variable names used in this material model and corresponding +symbols employed in the papers: +P12 +P22 +P33 G12 G22 G33 A +B0 +GAMMA C N +P12 +P22 +P33 𝐺12 𝐺22 𝐺33 +𝑎 +𝑏0 +𝛾 +𝑐 +𝑛 +TREF TMELT M ETA CP +DEPSO DEPSAD +R0 +𝑇𝑟 +𝑇𝑚 +𝑚 +𝜂𝑘 +𝐶𝑝 +𝜀̇𝑖𝑡/𝜀̇0 +𝜀̇𝑎 +𝜌 +History variables summary: +1. Damage accumulation: history variable #3. Elements will be deleted if this +variable reaches 1.0 for more than half of the through-thickness integration +points (Revision 109792). +2. Temperatures: history variable #4. +3. Strain rates: history variable #5. +4. Strain rate scale factors: history variable #6. +5. Temperature scale factor: history variable #7. +Keyword example input: +A sample material input card can be found below, with parameters from Mohr, D., et +al.(2010) and Roth, C.C., Mohr, D. (2014). +*MAT_MOHR_NON_ASSOCIATED_FLOW +$# mid R0 E PR P12 P22 P33 G12 + 1 7.8000E-9 2.10E05 0.300000 -0.5 1.0 3.0 -0.4946 +$ G22 G33 LCIDS LCIDV LCIDT LFLD LFRAC W0 + 0.9318 2.4653 100 105 102 +$ A B0 GAMMA C N SCALE + 1.97 0.82 0.025 0.00 0.199 3.132E-3 +$ TREF TMELT M ETA CP TINI DEPSO DEPSAD + 293.0 1673.70 0.921 0.9 420.0 293.0 0.001164 1.379 +$ AOPT + 3 +$ XP YP ZP A1 A2 A3 +$ V1 V2 V3 D1 D2 D3 BETA + 1.0 +*DEFINE_CURVE +100 + 0.00000E+00 0.30130E+03 + 0.10000E-01 0.42295E+03 + 0.20000E-01 0.47991E+03 + 0.30000E-01 0.52022E+03 + 0.40000E-01 0.55126E+03 +⋮ +⋮ +*DEFINE_CURVE +105 + 0.00000E+00 0.10000E+01 + 0.10000E+00 0.10608E+01 + 0.50000E+00 0.10828E+01 + 0.10000E+01 0.10923E+01 +⋮ +⋮ +*DEFINE_CURVE +102 + 0.29300E+03 0.10000E+01 + 0.33300E+03 0.96168E+00 + 0.37300E+03 0.92744E+00 + 0.41300E+03 0.89459E+00 + 0.45300E+03 0.86261E+00 +⋮ +⋮ +Revision information: +This material model is available in SMP starting in Revision 102375. Revision history is +listed below: +1) Element deletion feature based on damage accumulation: Revision 109792. +2) The option XUE is available starting on Revision 111531. +U n s +i n e d +s h e +Fy +0= +a x i a l +- +U n i +Fy +0= +1.2 +1.15 +1.1 +1.05 +1.0 +0.0 +1.0 +0.8 +0.6 +0.4 +0.2 +LCIDV +0.5 +1.0 +Strain rate (x103) +1.5 +2.0 +LCIDT +0.0 +0.4 +0.6 +0.8 +1.0 +1.2 +1.4 +Temperature (x103 kelvin) +Figure M260B-1. Uniaxial stretching on a single shell element; Input curves +LCIDV and LCIDT. +Pull speed: 15 mm/s, SCALE=1.0 +1000 +800 +600 +400 +200 +) +( +Input +no LCIDV, no LCIDT +no LCIDV, with LCIDT +with LCIDV, no LCIDT +with LCIDV, with LCIDT +0.0 +0.2 +0.4 +0.6 +0.8 +1.0 +Strain +3.0 +2.5 +2.0 +1.5 +1.0 +0.5 +0.0 +) +/ +( +- +# +Pull speed: 15 mm/s, SCALE=1.0 +0.1 +0.2 +Time (sec) +0.3 +500 +450 +400 +350 +300 +) +( +- +# +250 +0.4 +Figure M260B-2. Results of a single element uniaxial stretching - stress-strain +curves (top), strain rates and temperature history under various conditions. +*MAT_LAMINATED_FRACTURE_DAIMLER_PINHO +This is Material Type 261 which is an orthotropic continuum damage model for +laminated fiber-reinforced composites. See Pinho, Iannucci and Robinson [2006]. It is +based on a physical model for each failure mode and considers non-linear in-plane +shear behavior. +This model is implemented for shell, thick shell and solid elements. +Remark: Laminated shell theory can be applied by setting LAMSHT ≥ 3 in *CON- +TROL_SHELL. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +EA +F +3 +4 +EB +F +4 +5 +EC +F +5 +6 +7 +8 +PRBA +PRCA +PRCB +F +6 +F +7 +F +8 +Variable +GAB +GBC +GCA +AOPT +DAF +DKF +DMF +EFS +Type +F +F +F +F +F +F + Card 3 +Variable +1 +XP +Type +F + Card 4 +Variable +1 +V1 +Type +F +2 +YP +F +2 +V2 +F +3 +ZP +F +3 +V3 +F +4 +A1 +F +4 +D1 +F +5 +A2 +F +5 +D2 +F +F +7 +F +8 +7 +8 +6 +A3 +F +6 +D3 +MANGLE +F +Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ENKINK +ENA +ENB +ENT +ENL +Type +F +F +F +F +F + Card 6 +Variable +1 +XC +Type +F + Card 7 +1 +2 +XT +F +2 +3 +YC +F +3 +4 +YT +F +4 +5 +SL +F +5 +6 +7 +8 +Variable +FIO +SIGY +LCSS +BETA +PFL +PUCK +SOFT +Type +F +F +F +F +F +F +F + VARIABLE +DESCRIPTION +6 +7 +8 +DT +F +MID +RO +EA +EB +EC +PRBA +PRCA +PRCB +GAB +GBC +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +𝐸𝑎, Young’s modulus in 𝑎-direction (longitudinal) +𝐸𝑏, Young’s modulus in 𝑏-direction (transverse) +𝐸𝑐, Young’s modulus in 𝑐-direction +𝜈𝑏𝑎, Poisson’s ratio 𝑏𝑎 +𝜈𝑐𝑎, Poisson’s ratio 𝑐𝑎 +𝜈𝑐𝑏, Poisson’s ratio 𝑐𝑏 +𝐺𝑎𝑏, shear modulus 𝑎𝑏 +𝐺𝑏𝑐, shear modulus 𝑏𝑐 +GCA +AOPT +*MAT_LAMINATED_FRACTURE_DAIMLER_PINHO +DESCRIPTION +𝐺𝑐𝑎, shear modulus 𝑐𝑎 +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then, for shells only, rotated about +the shell element normal by an angle MANGLE. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the 𝑎-direction. This option is for solid +elements only. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle (MANGLE) from a line in the plane of the el- +ement defined by the cross product of the vector v with +the element normal. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector 𝐯, and +an originating point, 𝐩, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +DAF +Flag to control failure of an +longitudinal (fiber) tensile failure: +integration point based on +EQ.0.0: IP fails if any damage variable reaches 1.0. +EQ.1.0: no failure of IP due to fiber tensile failure. This +condition corresponds to history variable “da(i)” +reaching 1.0 +VARIABLE +DKF +DESCRIPTION +Flag to control failure of an +longitudinal (fiber) compressive failure: +integration point based on +EQ.0.0: IP fails if any damage variable reaches 1.0. +EQ.1.0: no failure of IP due to fiber compressive failure. This +condition corresponds to history variable “dkink(i)” +reaching 1.0. +DMF +Flag to control failure of an integration point based on transverse +(matrix) failure: +EQ.0.0: IP fails if any damage variable reaches 1.0. +EQ.1.0: no failure of IP due to matrix failure. This condition +corresponds to history variable “dmat(i)” reaching 1.0. +EFS +Maximum effective strain for element layer failure. A value of +unity would equal 100% strain. +GT.0.0: fails when effective strain calculated assuming material +is vol-ume preserving exceeds EFS. +LT.0.0: fails when effective strain calculated from the full +strain tensor exceeds |EFS|. +XP, YP, ZP +Coordinates of point p for AOPT = 1 and 4. +A1, A2, A3 +Define components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Define components of vector 𝐯 for AOPT = 3. +D1, D2, D3 +Define components of vector 𝐝 for AOPT = 2. +MANGLE +Material angle in degrees for AOPT = 0 (shells only) and +AOPT = 3. MANGLE may be overridden on the element card, +see *ELEMENT_SHELL_BETA and *ELEMENT_SOLID_ORTHO. +ENKINK +Fracture toughness for longitudinal (fiber) compressive failure +mode. +GT.0.0: The given value will be regularized with +the +characteristic element length. +LT.0.0: Load curve ID = (-ENKINK) which defines the fracture +toughness for fiber compressive failure mode as a func- +tion of characteristic element length. No further regu- +larization. +*MAT_LAMINATED_FRACTURE_DAIMLER_PINHO +DESCRIPTION +ENA +Fracture toughness for longitudinal (fiber) tensile failure mode. +GT.0.0: The given value will be regularized with +the +characteristic element length. +LT.0.0: Load curve ID = (-ENA) which defines the fracture +toughness for fiber tensile failure mode as a function of +characteristic element length. No further regulariza- +tion. +ENB +Fracture toughness for intralaminar matrix tensile failure. +GT.0.0: The given value will be regularized with +the +characteristic element length. +LT.0.0: Load curve ID = (-ENB) which defines the fracture +toughness for intralaminar matrix tensile failure as a +function of characteristic element length. No further +regularization. +ENT +Fracture toughness for intralaminar matrix transverse shear +failure. +GT.0.0: The given value will be regularized with +the +characteristic element length. +LT.0.0: Load curve ID = (-ENT) which defines the fracture +toughness for intralaminar matrix transverse shear +failure as a function of characteristic element length. +No further regularization. +ENL +Fracture toughness for intralaminar matrix longitudinal shear +failure. +GT.0.0: The given value will be regularized with +the +characteristic element length. +LT.0.0: Load curve ID = (-ENL) which defines the fracture +toughness for intralaminar matrix longitudinal shear +failure as a function of characteristic element length. +No further regularization. +XC +Longitudinal compressive strength, 𝑎-axis (positive value). +GT.0.0: constant value +LT.0.0: Load curve ID = (-XC) which defines the longitudinal +compressive strength vs. longitudinal strain rate (𝜖 ̇𝑎𝑎). +VARIABLE +DESCRIPTION +XT +Longitudinal tensile strength, 𝑎-axis. +GT.0.0: constant value +LT.0.0: Load curve ID = (-XT) which defines the longitudinal +tensile strength vs. longitudinal strain rate (𝜖 ̇𝑎𝑎). +YC +Transverse compressive strength, 𝑏-axis (positive value). +GT.0.0: constant value +LT.0.0: Load curve ID = (-YC) which defines the transverse +compressive strength vs. transverse strain rate (𝜖 ̇𝑏𝑏). +YT +Transverse tensile strength, 𝑏-axis. +GT.0.0: constant value +LT.0.0: Load curve ID = (-YT) which defines the transverse +tensile strength vs. tansverse strain rate (𝜖 ̇𝑏𝑏). +SL +Longitudinal shear strength. +GT.0.0: constant value +LT.0.0: Load curve ID = (-SL) which defines the longitudinal +shear strength vs. in-plane shear strain rate (𝜖 ̇𝑎𝑏). +FIO +Fracture angle in pure transverse compression (in degrees, +default = 53.0). +SIGY +In-plane shear yield stress. +*MAT_LAMINATED_FRACTURE_DAIMLER_PINHO +DESCRIPTION +LCSS +Load curve ID or Table ID. +Load Curve. When LCSS is a Load curve ID, it defines the non- +linear in-plane shear-stress as a function of in-plane shear-strain. +Tabular Data. The table maps in-plane strain rate values (𝜖 ̇𝑎𝑏) to +a load curve giving the in-plane shear-stress as a function of in- +plane shear-strain. For strain rates below the minimum value, the +curve for the lowest defined value of strain rate is used. +Likewise, when the strain rate exceeds the maximum value, the +curve for the highest defined value of strain rate is used. +Logarithmically Defined Table. If the first curve in the table +corresponds to a negative strain rate, LS-DYNA assumes that the +natural logarithm of the strain rate value is used for all stress- +strain curves. Since the tables are internally discretized to equally +spaced points, natural logarithms are necessary, for example, if +the curves correspond to rates from 10−4 to 104. Computing +natural logarithms can substantially increase the computational +time on certain computer architectures +BETA +Hardening parameter for in-plane shear plasticity (0.0 ≤ BETA ≤ +1.0). +EQ.0.0: +EQ.1.0: +Pure kinematic hardening +Pure isotropic hardening +0.0 < BETA < 1.0: mixed hardening. +PFL +Percentage of layers which must fail until crashfront is initiated. +E.g. |PFL| = 80.0, then 80% of layers must fail until strengths are +reduced in neighboring elements. Default: all layers must fail. A +single layer fails if 1 in-plane IP fails (PFL > 0) or if 4 in-plane IPs +fail (PFL < 0). +PUCK +Flag for evaluation and post-processing of Puck’s inter-fiber- +failure criterion (IFF, see Puck, Kopp and Knops [2002]). +EQ.0.0: no evaluation of Puck’s IFF-criterion. +EQ.1.0: Puck’s IFF-criterion will be evaluated. +SOFT +Softening reduction factor for material strength in crashfront +elements (default = 1.0). +am +−σ +cψ +c ψ +−σ +bψ +−σ +bc +bc +−σ +−σ +cb +cb +−σ +bm +bψ +cψ +−σ +bψ +bψ +ma +c ψ +Matrix fracture plane +−σ +cψ +bψ +mb +mb +Figure M261-1. Definition of angles and stresses in fracture plane + VARIABLE +DESCRIPTION +DT +Strain rate averaging option. +EQ.0.0: Strain rate is evaluated using a running average. +LT.0.0: Strain rate is evaluated using average of last 11 time +steps. +GT.0.0: Strain rate is averaged over the last DT time units. +Remarks: Failure Surfaces +The failure surface to limit the elastic domain is assembled by four sub-surfaces, +representing different failure mechanisms. See Figure M261-1 for definition of angles. +They are defined as follows: +1. +longitudinal (fiber) tension, +𝑓𝑎 = +𝜎𝑎 +𝑋𝑇 += 1 +2. +longitudinal (fiber) compression (3D-kinking model) – (transformation to +fracture plane), +) ++ ( +𝑓𝑘𝑖𝑛𝑘 = +⎧ +{{{ +⎨ +{{{ +⎩ +( +𝜏𝑇 +𝑆𝑇 − 𝜇𝑇𝜎𝑛 +𝜎𝑛 +𝑌𝑇 +) + ( ++ ( +𝜏𝑇 +𝑆𝑇 +𝜏𝐿 +𝑆𝐿 − 𝜇𝐿𝜎𝑛 +) ++ ( +) +) += 1 𝑖𝑓 𝜎𝑏𝑚 ≤ 0 += 1 𝑖𝑓 𝜎𝑏𝑚 > 0 +𝜏𝐿 +𝑆𝐿 +LS-DYNA R10.0 +Figure M261-2. Damage evolution law +𝑆𝑇 = +𝜎𝑛 = +𝑌𝐶 +2 tan(𝜙0) +𝜎𝑏𝑚 + 𝜎𝑐𝜓 + ; 𝜇𝑇 = − +tan(2𝜙0) + ; 𝜇𝐿 = 𝑆𝐿 +𝜇𝑇 +𝑆𝑇 ++ +𝜎𝑏𝑚 − 𝜎𝑐𝜓 +cos(2𝜙) + 𝜏𝑏𝑚𝑐𝜓 sin(2𝜙) +𝜏𝑇 = − +𝜎𝑏𝑚 − 𝜎𝑐𝜓 +sin(2𝜙) + 𝜏𝑏𝑚𝑐𝜓 cos(2𝜙) +𝜏𝐿 = 𝜏𝑎𝑚𝑏𝑚 cos(𝜙) + 𝜏𝑐𝜓𝑎𝑚 sin(𝜙) +3. +transverse (matrix) failure: transverse tension, +𝑓𝑚𝑎𝑡 = ( +𝜎𝑛 +𝑌𝑇 +) ++ ( +𝜏𝑇 +𝑆𝑇 +) ++ ( +) +𝜏𝐿 +𝑆𝐿 += 1 𝑖𝑓 𝜎𝑛 ≥ 0 +with +𝜎𝑛 = ++ +𝜎𝑏 + 𝜎𝑐 +𝜎𝑏 − 𝜎𝑐 +𝜎𝑏 − 𝜎𝑐 +cos(2𝜙) + 𝜏𝑏𝑐 sin(2𝜙) +sin(2𝜙) + 𝜏𝑏𝑐 cos(2𝜙) +𝜏𝑇 = − +𝜏𝐿 = 𝜏𝑎𝑏 cos(𝜙) + 𝜏𝑐𝑎 sin(𝜙) +4. +transverse (matrix) failure: transverse compression/shear, +𝑓𝑚𝑎𝑡 = ( +𝜏𝑇 +𝑆𝑇 − 𝜇𝑇𝜎𝑛 +) ++ ( +𝜏𝐿 +𝑆𝐿 − 𝜇𝐿𝜎𝑛 +) += 1 𝑖𝑓 𝜎𝑛 < 0 +Remarks: Damange Evolution: +As long as the stress state is located within the failure surface the model behaves +orthotropic elastic. When reaching the failure criteria the effective (undamaged) +stresses will be reduced by a factor of (1 − 𝑑), where the damage variable d represents +failure mechanisms +one of +the damage variables defined +the different +for +non-linearity defined via +*DEFINE_CURVE +Figure M261-3. Definition of non-linear in-plane shear behavior +(𝑑da, 𝑑kink, 𝑑mat). The growth of these damage variables is driven by a linear damage +evolution law based on fracture toughnesses (𝛤 → ENKINK, ENA, ENB, ENT, ENL) +and a characteristic internal element length, 𝐿, to account for objectivity. See Figure +M261-2. +Remarks: Nonlinear In-Plane Shear: +To account for the characteristic non-linear in-plane shear behavior of laminated fiber- +reinforced composites a 1D elasto-plastic formulation is coupled to a linear damage +behavior once the maximum allowable stress state for shear failure is reached. The non- +linearity of the shear behavior can be introduced via the definition of an explicit shear +stress vs. engineering shear strain curve (LCSS) with *DEFINE_CURVE. See Figure +M261-3 (in which epsilon designates engineering shear strain rather than tensorial shear +strain). +Remarks: References: +More detailed information about this material model can be found in Pinho, Iannucci +and Robinson [2006]. +Remarks: Element Deletion: +When failure has occurred in all the composite layers (through-thickness integration +points), the element is deleted. Elements which share nodes with the deleted element +become “crashfront” elements and can have their strengths reduced by using the SOFT +parameter. An earlier initiation of crashfront elements is possible by using the +parameter PFL. +Remarks: History Variables: +The number of additional integration point variables written to the LS-DYNA database +is input by the *DATABASE_EXTENT_BINARY definition with the variable NEIPS +(shells) and NEIPH (solids). These additional variables are tabulated below (i = +integration point): +History +Variable +Description +Value +LS-PrePost +history variable +fa(i) +fkink(i) +fmat(i) matrix mode +fiber tensile mode +fiber compressive mode +0 → 1: elastic +1: failure criterion rea- +ched +da(i) +dkink(i) +damage fiber tension +damage +compression +fiber +dmat(i) damage transverse +dam(i) +crashfront +fmt_p(i) +fmc_p(i) +theta_p(i) +tensile matrix mod +(Puck criteria) +compressive +mode +(Puck criteria) +angle of fracture plane +(radians, Puck criteria) +matrix +0: elastic +1: fully damaged +-1: element intact +10 - 8: element in +crashfront ++1: element failed +0 → 1: elastic +1: failure criterion rea- +ched +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +11 +12 +*MAT_LAMINATED_FRACTURE_DAIMLER_CAMANHO +This is Material Type 262 which is an orthotropic continuum damage model for +laminated fiber-reinforced composites. See Maimí, Camanho, Mayugo and Dávila +[2007]. It is based on a physical model for each failure mode and considers a simplified +non-linear in-plane shear behavior. This model is implemented for shell, thick shell and +solid elements. +NOTE: Laminated shell theory can be applied by setting +LAMSHT ≥ 3 in *CONTROL_SHELL. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +EA +F +3 +4 +EB +F +4 +5 +EC +F +5 +6 +7 +8 +PRBA +PRCA +PRCB +F +6 +F +7 +F +8 +Variable +GAB +GBC +GCA +AOPT +DAF +DKF +DMF +EFS +Type +F +F +F +F +F +F + Card 3 +Variable +1 +XP +Type +F + Card 4 +Variable +1 +V1 +Type +F +2 +YP +F +2 +V2 +F +3 +ZP +F +3 +V3 +F +4 +A1 +F +4 +D1 +F +5 +A2 +F +5 +D2 +F +F +7 +F +8 +7 +8 +6 +A3 +F +6 +D3 +MANGLE +F +Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +GXC +GXT +GYC +GYT +GSL +GXCO +GXTO +Type +F +F +F +F +F + Card 6 +Variable +1 +XC +Type +F + Card 7 +1 +2 +XT +F +2 +3 +YC +F +3 +4 +YT +F +4 +5 +SL +F +5 +F +6 +F +7 +XCO +XTO +F +6 +F +7 +Variable +FIO +SIGY +ETAN +BETA +PFL +PUCK +SOFT +Type +F +F +F +F +F +F +F +8 +8 +DT +F + VARIABLE +DESCRIPTION +MID +RO +EA +EB +EC +PRBA +PRCA +PRCB +GAB +GBC +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density +𝐸𝑎, Young’s modulus in 𝑎-direction (longitudinal) +𝐸𝑏, Young’s modulus in 𝑏-direction (transverse) +𝐸𝑐, Young’s modulus in 𝑐-direction +𝜈𝑏𝑎, Poisson’s ratio 𝑏𝑎 +𝜈𝑐𝑎, Poisson’s ratio 𝑐𝑎 +𝜈𝑐𝑏, Poisson’s ratio 𝑐𝑏 +𝐺𝑎𝑏, shear modulus 𝑎𝑏 +𝐺𝑏𝑐, shear modulus 𝑏𝑐 +VARIABLE +DESCRIPTION +GCA +AOPT +𝐺𝑐𝑎, shear modulus 𝑐𝑎 +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then, for shells only, rotated about +the shell element normal by an angle MANGLE. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the 𝑎-direction. This option is for solid +elements only. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle (MANGLE) from a line in the plane of the el- +ement defined by the cross product of the vector v with +the element normal. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector 𝐯, and +an originating point, 𝐩, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +DAF +Flag to control failure of an +longitudinal (fiber) tensile failure: +integration point based on +EQ.0.0: IP fails if any damage variable reaches 1.0. +EQ.1.0: no failure of IP due to fiber tensile failure, da(i)=1.0 +DKF +*MAT_LAMINATED_FRACTRURE_DAIMLER_CAMANHO +DESCRIPTION +Flag to control failure of an +longitudinal (fiber) compressive failure: +integration point based on +EQ.0.0: IP fails if any damage variable reaches 1.0. +EQ.1.0: no failure of IP due to fiber compressive failure, +dkink(i) = 1.0. +DMF +Flag to control failure of an integration point based on transverse +(matrix) failure: +EQ.0.0: IP fails if any damage variable reaches 1.0. +EQ.1.0: no failure of IP due to matrix failure, dmat(i)=1.0 +EFS +Maximum effective strain for element layer failure. A value of +unity would equal 100% strain. +GT.0.0: fails when effective strain calculated assuming material +is vol-ume preserving exceeds EFS. +LT.0.0: fails when effective strain calculated from the full +strain tensor exceeds |EFS|. +XP YP ZP +Coordinates of point 𝐩 for AOPT = 1 and 4. +A1 A2 A3 +Define components of vector 𝐚 for AOPT = 2. +V1 V2 V3 +Define components of vector 𝐯 for AOPT = 3. +D1 D2 D3 +Define components of vector 𝐝 for AOPT = 2. +MANGLE +Material angle in degrees for AOPT = 0 (shells only) and +AOPT = 3. MANGLE may be overridden on the element card, +see *ELEMENT_SHELL_BETA and *ELEMENT_SOLID_ORTHO. +GXC +Fracture toughness for longitudinal (fiber) compressive failure +mode. +GT.0.0: The given value will be regularized with +the +characteristic element length. +LT.0.0: Load curve ID = (-GXC) which defines the fracture +toughness for fiber compressive failure mode as a func- +tion of characteristic element length. No further regu- +larization. +VARIABLE +DESCRIPTION +GXT +Fracture toughness for longitudinal (fiber) tensile failure mode. +GT.0.0: The given value will be regularized with +the +characteristic element length. +LT.0.0: Load curve ID = (-GXT) which defines the fracture +toughness for fiber tensile failure mode as a function of +characteristic element length. No further regulariza- +tion. +GYC +Fracture toughness for transverse compressive failure mode. +GT.0.0: The given value will be regularized with +the +characteristic element length. +LT.0.0: Load curve ID = (-GYC) which defines the fracture +toughness for transverse compressive failure mode as a +function of characteristic element length. No further +regularization. +GYT +Fracture toughness for transverse tensile failure mode. +GT.0.0: The given value will be regularized with +the +characteristic element length. +LT.0.0: Load curve ID = (-GYT) which defines the fracture +toughness for transverse tensile failure mode as a func- +tion of characteristic element length. No further regu- +larization. +GSL +Fracture toughness for in-plane shear failure mode. +GT.0.0: The given value will be regularized with +the +characteristic element length. +LT.0.0: Load curve ID = (-GSL) which defines the fracture +toughness for in-plane shear failure mode as a function +of characteristic element length. No further regulariza- +tion. +GXCO +*MAT_LAMINATED_FRACTRURE_DAIMLER_CAMANHO +DESCRIPTION +Fracture toughness for longitudinal (fiber) compressive failure +mode to define bi-linear damage evolution. +GT.0.0: The given value will be regularized with +the +characteristic element length. +LT.0.0: Load curve ID = (-GXCO) which defines the fracture +toughness for fiber compressive failure mode to define +bi-linear damage evolution as a function of characteris- +tic element length. No further regularization. +GXTO +Fracture toughness for longitudinal (fiber) tensile failure mode to +define bi-linear damage evolution. +GT.0.0: The given value will be regularized with +the +characteristic element length. +LT.0.0: Load curve ID = (-GXTO) which defines the fracture +toughness for fiber tensile failure mode to define bi- +linear damage evolution as a function of characteristic +element length. No further regularization. +XC +Longitudinal compressive strength, 𝑎-axis (positive value). +GT.0.0: constant value +LT.0.0: Load curve ID = (-XC) which defines the longitudinal +compressive strength vs. longitudinal strain rate (𝜖 ̇𝑎𝑎). +XT +Longitudinal tensile strength, 𝑎-axis. +GT.0.0: constant value +LT.0.0: Load curve ID = (-XT) which defines the longitudinal +tensile strength vs. longitudinal strain rate (𝜖 ̇𝑎𝑎). +YC +Transverse compressive strength, 𝑏-axis (positive value). +GT.0.0: constant value +LT.0.0: Load curve ID = (-YC) which defines the transverse +compressive strength vs. transverse strain rate (𝜖 ̇𝑏𝑏). +YT +Transverse tensile strength, 𝑏-axis. +GT.0.0: constant value +LT.0.0: Load curve ID = (-YT) which defines the transverse +tensile strength vs. transverse strain rate (𝜖 ̇𝑏𝑏). +VARIABLE +DESCRIPTION +SL +Shear strength, 𝑎𝑏 plane. +GT.0.0: constant value +LT.0.0: Load curve ID = (-SL) which defines the longitudinal +shear strength vs. in-plane shear strain rate (𝜖 ̇𝑎𝑏). +XCO +Longitudinal compressive strength at inflection point (positive +value). +GT.0.0: constant value +LT.0.0: Load curve ID = (-XCO) which defines the longitudinal +compressive strength at inflection point vs. longitudi- +nal strain rate (𝜖 ̇𝑎𝑎). +XTO +Longitudinal tensile strength at inflection point. +GT.0.0: constant value +LT.0.0: Load curve ID = (-XTO) which defines the longitudinal +tensile strength at inflection point vs. longitudinal +strain rate (𝜖 ̇𝑎𝑎). +FIO +Fracture angle in pure transverse compression (in degrees, +default = 53.0). +SIGY +In-plane shear yield stress. +GT.0.0: constant value +LT.0.0: Load curve ID = (-SIGY) which defines the in-plane +shear yield stress vs. in-plane shear strain rate (𝜖 ̇𝑎𝑏). +ETAN +Tangent modulus for in-plane shear plasticity. +GT.0.0: constant value +LT.0.0: Load curve ID = (-ETAN) which defines the tangent +modulus for in-plane shear plasticity vs. in-plane +shear strain rate (𝜖 ̇𝑎𝑏). +BETA +Hardening parameter for in-plane shear plasticity (0.0 ≤ BETA ≤ +1.0). +EQ.0.0: +EQ.1.0: +Pure kinematic hardening +Pure isotropic hardening +0.0 < BETA < 1.0: mixed hardening. +PFL +*MAT_LAMINATED_FRACTRURE_DAIMLER_CAMANHO +DESCRIPTION +Percentage of layers which must fail until crashfront is initiated. +E.g. |PFL| = 80.0, then 80% of layers must fail until strengths are +reduced in neighboring elements. Default: all layers must fail. A +single layer fails if 1 in-plane IP fails (PFL > 0) or if 4 in-plane IPs +fail (PFL < 0). +PUCK +Flag for evaluation and post-processing of Puck’s inter-fiber- +failure criterion (IFF, see Puck, Kopp and Knops [2002]). +EQ.0.0: no evaluation of Puck’s IFF-criterion. +EQ.1.0: Puck’s IFF-criterion will be evaluated. +SOFT +Softening reduction factor for material strength in crashfront +elements (default = 1.0). +DT +Strain rate averaging option. +EQ.0.0: Strain rate is evaluated using a running average. +LT.0.0: Strain rate is evaluated using average of last 11 time +steps. +GT.0.0: Strain rate is averaged over the last DT time units. +Remarks: +The failure surface to limit the elastic domain is assembled by four sub-surfaces, +representing different failure mechanisms. They are defined as follows: +1. +longitudinal (fiber) tension, +𝜙1+ = +𝜎11 − 𝜐12𝜎22 +𝑋𝑇 += 1 +2. +longitudinal (fiber) compression – (transformation to fracture plane), +𝜙1− = +⟨∣𝜎12 +𝑚 ∣ + 𝜇𝐿𝜎22 +𝑚 ⟩ +𝑆𝐿 += 1 +with +𝜇𝐿 = − +𝑆𝐿 cos(2𝜙0) +𝑌𝐶cos2(𝜙0) +𝜎22 +𝑚 = 𝜎11sin2(𝜑𝑐) + 𝜎22cos2(𝜑𝑐) − 2|𝜎12| sin(𝜑𝑐) cos(𝜑𝑐) +𝑚 = (𝜎22 − 𝜎11) sin(𝜑𝑐) cos(𝜑𝑐) + |𝜎12|(cos2(𝜑𝑐) − sin2(𝜑𝑐)) +𝜎12 +and +𝜑𝑐 = arctan +⎡1 − √1 − 4 ( +⎢ +⎢ +⎢ +⎢ +⎣ +𝑆𝐿 +𝑋𝐶 +2 ( +𝑆𝐿 +𝑋𝐶 ++ 𝜇𝐿) +𝑆𝐿 +𝑋𝐶 ++ 𝜇𝐿) +⎤ +⎥ +⎥ +⎥ +⎥ +⎦ +3. +transverse (matrix) failure: perpendicular to the laminate mid-plane, +𝜙2+ = +⎧ +{ +{ +{ +⎨ +{ +{ +{ +⎩ +√(1 − 𝑔) +𝜎22 +𝑌𝑇 ++𝑔 ( +𝜎22 +𝑌𝑇 +) ++ ( +) +𝜎12 +𝑆𝐿 += 1 𝜎22 ≥ 0 +⟨|𝜎12| + 𝜇𝐿𝜎22⟩ +𝑆𝐿 += 1 +𝜎22 < 0 +4. +transverse (matrix) failure: transverse compression/shear, +𝜙2− = √( +𝜏𝑇 +𝑆𝑇 +) ++ ( +𝜏𝐿 +𝑆𝐿 +) += 1 𝑖𝑓 𝜎22 < 0 +with +𝜇𝑇 = − +tan(2𝜙0) +𝑆𝑇 = 𝑌𝐶 cos(𝜙0) [sin(𝜙0) + +𝜃 = arctan ( +−|𝜎12| +𝜎22 sin(𝜙0) +) +cos(𝜙0) +tan(2𝜙0) +] +𝜏𝑇 = ⟨−𝜎22 cos(𝜙0) [sin(𝜙0) − 𝜇𝑇 cos(𝜙0) cos(𝜃)]⟩ +𝜏𝐿 = ⟨cos(𝜙0) [|𝜎12| + 𝜇𝐿𝜎22 cos(𝜙0) sin(𝜃)]⟩ +So long as the stress state is located within the failure surface the model behaves +orthotropic elastic. The constitutive law is derived on basis of a proper definition for +the ply complementary free energy density 𝐺, whose second derivative with respect to +the stress tensor leads to the compliance tensor 𝐇 +𝐇 = +𝜕2𝐺 +𝜕𝜎 2 = +(1 − 𝑑1)𝐸1 +𝜐12 +𝐸1 +− +− +𝜐21 +𝐸2 +(1 − 𝑑2)𝐸2 +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +(1 − 𝑑6)𝐺12⎦ +, +𝑑1 = 𝑑1+ +𝑑2 = 𝑑2+ +〈𝜎11〉 +|𝜎11| +〈𝜎22〉 +|𝜎22| ++ 𝑑1− ++ 𝑑2− +〈−𝜎11〉 +|𝜎11| +〈−𝜎22〉 +|𝜎22| +Damage evolution: +Figure M262-1. Damage evolution law +Figure M262-2. In-plane shear behavior +Once the stress state reaches the failure criterion a set of scalar damage variables +(𝑑1−, 𝑑1+, 𝑑2−, 𝑑2+, 𝑑6) is introduced associated with the different failure mechanisms. +A bi-linear (longitudinal direction) and a linear (transverse direction) damage evolution +law is utilized to define the development of the damage variables driven by the fracture +toughness and a characteristic internal element length to account for objectivity. See +Figure M262-1. +To account for the characteristic non-linear in-plane shear behavior of laminated fiber- +reinforced composites a 1D elasto-plastic formulation with linear hardening is coupled +to a linear damage behavior once the maximum allowable stress state for shear failure is +reached. See Figure M262-2. +More detailed information about this material model can be found in Maimí, Camanho, +Mayugo and Dávila [2007]. +When failure has occurred in all the composite layers (through-thickness integration +points), the element is deleted. Elements which share nodes with the deleted element +become “crashfront” elements and can have their strengths reduced by using the SOFT +parameter. An earlier initiation of crashfront elements is possible by using the +parameter PFL. +The number of additional integration point variables written to the LS-DYNA database +is input by the *DATABASE_EXTENT_BINARY definition with the variable NEIPS +(shells) and NEIPH (solids). These additional variables are tabulated below (i = +integration point): +Description +Value +LS-PrePost +history variable +History +Variable +𝜙1+(i) +𝜙1−(i) +𝜙2+(i) +𝜙2−(i) +𝑑1+(i) +𝑑1−(i) +𝑑2(i) +𝑑6(i) +fiber tensile mode +fiber compressive +tensile matrix mode +compressive +mode +damage fiber tension +damage +compression +damage transverse +damage in-plane shear +matrix +fiber +dam(i) +crashfront +fmt_p(i) +fmc_p(i) +theta_p(i) +tensile matrix mod +(Puck criteria) +compressive +mode +(Puck criteria) +angle of fracture plane +(radians, Puck criteria) +matrix +0 → 1: elastic +1: failure criterion rea- +ched +0: elastic +1: fully damaged +-1: element intact +10 - 8: element in +crashfront ++1: element failed +0 → 1: elastic +1: failure criterion +reached +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +11 +12 +*MAT_TABULATED_JOHNSON_COOK_ORTHO_PLASTICITY +This is Material Type 264. This is an orthotropic elastic plastic material law with J3 +dependent yield surface. This material considers tensile/compressive asymmetry in the +material response, which is important for HCP metals like Titanium. The model is +available for solid elements. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +CP +F +6 +TR +F +7 +8 +BETA +NUMINT +F +F +Default +none +none +none +none +none +0.0 +1.0 +1.0 + Card 2 +1 +2 +3 +4 +5 +Variable +LCT00R +LCT00T +LCF +LCG +LCH +Type +Default +F +0 + Card 3 +1 +F +0 +2 +F +0 +3 +F +0 +4 +Variable +LCC00R +LCC00T +LCS45R +LCS45T +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +5 +F +0 +6 +LCI +F +0 +6 +7 +8 +7 +8 +SFIEPM +NITER +AOPT +F +F +1 +100 +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCT90R +LCT45R +LCTTHR +LCC90R +LCC45R +LCCTHR +Type +Default +F +0 + Card 5 +1 +F +0 +2 +F +0 +3 +F +0 +4 +F +0 +5 +F +0 +6 +Variable +LCT90T +LCT45T +LCTTHT +LCC90T +LCC45T +LCCTHT +F +0 +2 +YP +F +2 +V2 +F +F +0 +3 +ZP +F +3 +V3 +F +F +0 +4 +A1 +F +4 +D1 +F +F +0 +5 +A2 +F +5 +D2 +F +F +0 +6 +A3 +F +6 +D3 +F +7 +8 +7 +8 +MACF +F +7 +BETA +F +8 +Type +Default + Card 6 +Variable +F +0 +1 +XP +Type +F + Card 7 +Variable +1 +V1 +Type +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +*MAT_TABULATED_JOHNSON_COOK_ORTHO_PLASTICITY +DESCRIPTION +E +Young’s modulus: +GT.0.0: constant value is used +LT.0.0: temperature dependent Young’s modulus given by +load curve ID = -E +PR +CP +TR +Poisson’s ratio. +Specific heat. +Room temperature. +BETA +Fraction of plastic work converted into heat. +NUMINT +Number of integration points which must fail before the element +is deleted. +LCT00R +LCT00T +LCF +LCG +LCH +LCI +EQ.-200: Turns off erosion for solids. Not recommended +unless used in conjunction with *CONSTRAINED_- +TIED_NODES_FAILURE. +Table ID defining for each plastic strain rate value a load curve ID +giving the (isothermal) tensile yield stress versus plastic strain for +that rate in the 00 degree direction. +Table ID defining for each temperature value a load curve ID +giving the (quasi-static) tensile yield stress versus plastic strain +for that temperature in the 00 degree direction. +Load curve ID or Table ID. The load curve ID defines plastic +failure strain as a function of triaxiality. The table ID defines for +each Lode parameter a load curve ID giving the plastic failure +strain versus triaxiality for that Lode parameter. (Table option +only for solids and not yet generally supported). +Load curve ID defining plastic failure strain as a function of +plastic strain rate. +Load curve ID defining plastic failure strain as a function of +temperature +Load curve ID or Table ID. The load curve ID defines plastic +failure strain as a function of element size. The table ID defines +for each triaxiality a load curve ID giving the plastic failure strain +versus element size for that triaxiality. +VARIABLE +LCC00R +LCC00T +LCS45R +LCS45T +DESCRIPTION +Table ID. The curves in this table define compressive yield stress +as a function of plastic strain. The table ID defines for each plastic +strain rate value a load curve ID giving the (isothermal) +compressive yield stress versus plastic strain for that rate in the 00 +direction. +Table ID defining for each temperature value a load curve ID +giving the (quasi-static) compressive yield stress versus strain for +that temperature. The curves in this table define compressive +yield stress as a function of plastic strain in the 00 direction. +Table ID. The load curves define shear yield stress in function of +plastic strain. The table ID defines for each plastic strain rate +value a load curve ID giving the (isothermal) shear yield stress +versus plastic strain for that rate in the 45 degree direction. +Table ID defining for each temperature value a load curve ID +giving the (quasi-static) shear yield stress versus strain for that +temperature. The load curves define shear yield stress as a +function of plastic strain or effective plastic strain in +the 45 degree direction. +SFIEPM +Scale factor on the initial estimate of the plastic multiplier. +NITER +Maximum number of iterations for the plasticity algorithm +AOPT +LCT90R +LCT45R +LCTTHR +LCC90R +LCC45R +*MAT_TABULATED_JOHNSON_COOK_ORTHO_PLASTICITY +DESCRIPTION +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES, and then rotated about the shell ele- +ment normal by an angle BETA. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available with the R3 release +of Version 971 and later. +Table ID defining for each plastic strain rate value a load curve ID +giving the (isothermal) tensile yield stress versus plastic strain +for that rate in the 90 degree direction. +Table ID defining for each plastic strain rate value a load curve ID +giving the (isothermal) tensile yield stress versus plastic strain for +that rate in the 45 degree direction. +Table ID defining for each plastic strain rate value a load curve ID +giving the (isothermal) tensile yield stress versus plastic strain for +that rate in the thickness degree direction. +Table ID defining for each plastic strain rate value a load curve ID +giving the (isothermal) compressive yield stress versus plastic +strain for that rate in the 90 degree direction. +Table ID defining for each plastic strain rate value a load curve ID +giving the (isothermal) compressive yield stress versus plastic +strain for that rate in the 45 degree direction. +VARIABLE +LCCTHR +LCT90T +LCT45T +LCTTHT +LCC90T +LCC45T +LCCTHT +DESCRIPTION +Table ID defining for each plastic strain rate value a load curve ID +giving the (isothermal) compressive yield stress versus plastic +strain for that rate in the thickness degree direction. +Table ID defining for each temperature value a load curve ID +giving the (quasistatic) tensile yield stress versus plastic strain +for that rate in the 90 degree direction. +Table ID defining for each temperature value a load curve ID +giving the (quasistatic) tensile yield stress versus plastic strain for +that rate in the 45 degree direction. +Table ID defining for each temperature value a load curve ID +giving the (quasistatic) tensile yield stress versus plastic strain for +that rate in the thickness degree direction. +Table ID defining for each temperature value a load curve ID +giving the (quasistatic) compressive yield stress versus plastic +strain for that rate in the 90 degree direction. +Table ID defining for each temperature value a load curve ID +giving the (quasistatic) compressive yield stress versus plastic +strain for that rate in the 45 degree direction. +Table ID defining for each temperature value a load curve ID +giving the (quasistatic) compressive yield stress versus plastic +strain for that rate in the thickness degree direction. +A1, A2, A3 +Components of vector 𝐚 for AOPT = 2. +MACF +Material axes change flag for brick elements: +EQ.1: No change, default, +EQ.2: switch material axes 𝑎 and 𝑏, +EQ.3: switch material axes 𝑎 and 𝑐, +EQ.4: switch material axes 𝑏 and 𝑐. +V1, V2, V3 +Components of vector 𝐯 for AOPT = 3. +D1, D2, D3 +Components of vector 𝐝for AOPT = 2. +BETA +Material angle in degrees for AOPT = 0 and 3, may be overridden +on the element card, see *ELEMENT_SHELL_BETA. +*MAT_TABULATED_JOHNSON_COOK_ORTHO_PLASTICITY +If IFLAG = 0 the compressive and shear curves are defined as follows: +σ𝑐(𝜀𝑝𝑐, 𝜀̇𝑝𝑐), 𝜀𝑝𝑐 = 𝜀𝑐 − +σ𝑠(𝛾𝑝𝑠, 𝛾̇𝑝𝑠), 𝛾𝑝𝑠 = 𝛾𝑠 − +𝜎𝑐 +𝜎𝑠 +, 𝜀̇𝑝𝑐 = +, 𝛾̇𝑝𝑠 = +𝜕𝜀𝑝𝑐 +𝜕𝑡 +𝜕𝛾𝑝𝑠 +𝜕𝑡 +and two new history variables (#15 plastic strain in compression and #16 plastic strain +in shear) are stored in addition to those history variables already stored in MAT_224. +If IFLAG = 1 the compressive and shear curves are defined as follows: +σ𝑐(𝜆̇, 𝜆), 𝜎𝑠(𝜆̇, 𝜆), 𝑊𝑝̇ = 𝜎eff𝜆̇ +History variables may be post-processed through additional variables. The number of +additional variables for solids written to the d3plot and d3thdt databases is input by the +optional *DATABASE_EXTENT_BINARY card as variable NEIPH. The relevant +additional variables of this material model are tabulated below: +LS-PrePost history +variable # +5 +6 +7 +8 +9 +10 +11 +12 +13 +14 +15 +16 +Solid elements +plastic strain rate +Compressive plastic strain +Shear plastic strain +plastic failure strain +triaxiality +Lode parameter +plastic work +ratio of plastic strain to plastic failure strain +element size +temperature +plastic strain in compression +plastic strain in shear +*MAT_TISSUE_DISPERSED +This is Material Type 266. This material is an invariant formulation for dispersed +orthotropy in soft tissues, e.g., heart valves, arterial walls or other tissues where one or +two collagen fibers are used. The passive contribution is composed of an isotropic and +two anisotropic parts. The isotropic part is a simple neo-Hookean model. The first +anisotropic part is passive, with two collagen fibers to choose from: (1) a simple +exponential model and (2) a more advanced crimped fiber model from Freed et al. +[2005]. The second anisotropic part is active described in Guccione et al. [1993] and is +used for active contraction. + Card 1 +1 +Variable +MID +Type +I + Card 2 +1 +2 +RO +F +2 +Variable +FID +ORTH +Type +I + Card 3 +1 +I +2 +3 +F +F +3 +C1 +F +3 +4 +5 +6 +7 +8 +SIGMA +MU +KAPPA +ACT +INIT +F +F +4 +C2 +F +4 +5 +C3 +F +5 +F +6 +I +7 +THETA +NHMOD +F +6 +F +7 +I +8 +8 +Variable +ACT1 +ACT2 +ACT3 +ACT4 +ACT5 +ACT6 +ACT7 +ACT8 +Type +F + Card 4 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +ACT9 +ACT10 +Type +F +Card 5 +1 +2 +Variable +AOPT +BETA +Type +I +F + Card 6 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +XP +F +3 +V3 +F +4 +YP +F +4 +D1 +F +5 +ZP +F +5 +D2 +F +6 +A1 +F +6 +D3 +F +7 +A2 +F +7 +8 +A3 +F +8 + VARIABLE +DESCRIPTION +MID +Material identification. A unique number must be specified. +RO +F +SIGMA +Mass density. +Fiber dispersion parameter governs the extent to which the fiber +dispersion extends to the third dimension. F = 0 and F = 1 apply +to 2D splay with the normal to the membrane being in the 𝛽 and +the 𝛾-directions, respectively . F = 0.5 applies +to 3D splay with transverse isotropy. Splay will be orthotropic +wheneverF ≠ 0.5. This parameter is ignored if INIT = 1. +The parameter SIGMA governs the extent of dispersion, such that +as SIGMA goes to zero, the material symmetry reduces to pure +transverse isotropy. Conversely, as SIGMA becomes large, the + This +material symmetry becomes isotropic in the plane. +parameter is ignored if INIT = 1. +MU +MU is the isotropic shear modulus that models elastin. MU +should be chosen such that the following relation is satisfied: +0.5 (3KAPPA − 2MU) (3KAPPA + MU) +⁄ +< 0.5. +Instability can occur for implicit simulations if this quotient is +close to 0.5. A modest approach is a quotient between 0.495 and +0.497. +KAPPA +Bulk modulus for the hydrostatic pressure. +ACT +INIT +FID +ORTH +*MAT_TISSUE_DISPERSED +DESCRIPTION +ACT = 1 indicates that an active model will be used that acts in +the mean fiber-direction. The active model, like the passive +model, will be dispersed by SIGMA and F, or if INIT = 1, with the +*INITIAL_FIELD_SOLID keyword. +INIT = 1 indicates that the anisotropy eigenvalues will be given +by *INITIAL_FIELD_SOLID variables in the global coordinate +system . +The passive fiber model number. There are two passive models +available: FID = 1 or FID = 2. They are described in Remark 2. +ORTH specifies the number (1 or 2) of fibers used. When +ORTH = 2 two fiber families are used and arranges symmetrically +THETA degrees from the mean fiber direction and lying in the +tissue plane. +C1-C3 +Passive fiber model parameters. +THETA +The angle between the mean fiber direction and the fiber families. +The parameter is active only if ORTH = 2 and is particularly +important in vascular tissues (e.g. arteries) +NHMOD +Neo-Hooke model flag +ACT1 - +ACT10 +AOPT +EQ.0.0: original implementation (modified Neo-Hooke) +EQ.1.0: standard Neo-Hooke model (as in umat45 of dyn21.f) +Active fiber model parameters. Note that ACT10 is an input for a +time dependent load curve that overrides some of the ACTx +values. See section 2 below. +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +2 +𝛽 +3 +𝛾 +𝛼 +Figure M266-1. The plot on the left relates the global coordinates (1, 2, 3) to +the local coordinates (𝛼, 𝛽, 𝛾), selected so the mean fiber direction in the +reference configuration is align with the 𝛼–axis. The plots on the right show +how the unit vector for a specific fiber within the fiber distribution of a 3D +tissue is oriented with respect to the mean fiber direction via angles 𝜃 and 𝜙. + VARIABLE +DESCRIPTION +defined by the cross product of the vector v with the +element normal. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available with the R3 release +of Version 971 and later. +BETA +P1 - P3 +Material angle in degrees for AOPT = 3, may be overridden on +the element card *ELEMANT_SOLID_ORTHO. +P1, P2 and P3 define the coordinates of point P for AOPT = 1 and +AOPT = 4. +A1 - A3 +A1, A2 and A3 define the components of vector A for AOPT = 2. +D1 - D3 +D1, D2 and D3 define components of vector D for AOPT = 2. +V1 - V3 +V1, V2 and V3 define components of vector V for AOPT = 3 and +AOPT = 4. +Details of the passive model can be found in Freed et al. (2005) and Einstein et al. +(2005). The stress in the reference configuration consists of a deviatoric matrix term, a +hydrostatic pressure term, and either one (ORTHO = 1) or two (ORTH = 2) fiber terms: +𝐒 = 𝜅𝐽(𝐽 − 1)𝐂−1 + 𝜇𝐽−2 3⁄ 𝐃𝐄𝐕 [ +(𝐈 − 𝐂̅−2)] + 𝐽−2 3⁄ ∑[𝜎𝑖(𝜆𝑖) + 𝜀𝑖(𝜆𝑖)]𝐃𝐄𝐕[𝐊𝑖] +𝑖=1 +where S is the second Piola-Kirchhoff stress tensor, J is the Jacobian of the deformation +gradient, 𝜅 is the bulk modulus, 𝜎𝑖 is the passive fiber stress model used, and 𝜀𝑖 is the +corresponding active fiber model used. The operator DEV is the deviatoric projection: +𝐃𝐄𝐕[•] = (•) − +tr[(•)𝐂]𝐂−1 +where C is the right Cauchy-Green deformation tensor. The dispersed fourth invariant +𝜆 = √tr[𝐊𝐂̅], where 𝐂̅is the isochoric part of the Cauchy-Green deformation. Note that +𝜆 is not a stretch in the classical way, since K embeds the concept of dispersion. K is +called the dispersion tensor or anisotropy tensor and is given in global coordinates. The +passive and active fiber models are defined in the fiber coordinate system. In effect the +dispersion tensor rotates and weights these one dimensional models, such that they are +both three-dimensional and in the Cartesian framework. +In the case where, the splay parameters SIGMA and F are specified, K is given by: +𝐊𝑖 = +𝐐𝑖 +⎡1 + 𝑒−2SIGMA2 +⎢⎢⎢ +⎣ +F(1 − 𝑒−2SIGMA2 +) 0 +(1 − F)(1 − 𝑒−2SIGMA2 +𝑇 +𝐐𝑖 +⎤ +⎥⎥⎥ +)⎦ +where Q is the transformation tensor that rotates from the local to the global Cartesian +system. In the case when INIT = 1, the dispersion tensor is given by +𝐊𝑖 = 𝐐𝑖 +𝜒𝑖 +⎜⎜⎜⎜⎛ +⎝ +𝜒𝑖 +⎟⎟⎟⎟⎞ +3⎠ +𝜒𝑖 +𝑇 +𝐐𝑖 +where the 𝜒:s are given on the *INITIAL_FIELD_SOLID card. For the values to be +3 = 1. It is the responsibility of the user to assure that +physically meaningful 𝜒𝑖 +this condition is met, no internal checking for this is done. These values typically come +from diffusion tensor data taken from the myocardium. +2 + 𝜒𝑖 +1 + 𝜒𝑖 +Remarks: +1. Passive fiber models. Currently there are two models available. +a) If FID = 1 a crimped fiber model is used. It is solely developed for colla- +gen fibers. Given 𝐻0 and 𝑅0 compute: +𝐿0 = √(2𝜋)2 + (𝐻0)2, Λ = +𝐿0 +𝐻0 +and +2.5 +1.5 +0.5 +0.98 +Crimped Model +Exp Model +1.02 +1.04 +1.06 +1.08 +1.1 +1.12 +1.14 +1.16 +Stretch +Figure M266-2. both the Crimped and the Exponential fiber models +visualized. Here ۓ = 1.1 is the transition point in the crimped model. +𝐸𝑓 𝐻0 +. +𝐸𝑠 = +𝐻0 + (1 + 37 +6𝜋2 + 2 +Now if the fiber stretches 𝜆 < Λ the fiber stress is given by: +𝐿0 +𝜋2) (𝐿0 − 𝐻0) +𝜉 = +where +𝜎 = 𝜉 𝐸𝑠(𝜆 − 1) +6𝜋2(Λ2 + (4𝜋2 − 1)𝜆2)𝜆 +Λ(3𝐻0 +2(Λ2 − 𝜆2)(3Λ2 + (8𝜋2 − 3)𝜆2) + 8𝜋2(10Λ2 + (3𝜋2 − 10)𝜆2)) +and if 𝜆 > Λ the fiber stress equals: +𝜎 = 𝐸𝑠(𝜆 − 1) + 𝐸𝑓 (𝜆 − Λ). +In Figure M266-1 the fiber stress is rendered with 𝐻0 = 27.5, 𝑅0 = 2 and +the transition point becomes Λ = 1.1. +b) The second fiber model available (FID = 2) is a simpler but more useful +model for the general fiber reinforced rubber. The fiber stress is simply +given by: +𝜎 = 𝐶1 [𝑒 +𝐶2 +(𝜆2−1) +− 1]. +The difference between the two fiber models is given in Figure M266-2. +The active model for myofibers (ACT = 1) is defined in Guccione et al. (1993) +and is given by: +𝜎 = 𝑇max +where +𝐶𝑎0 +2 + 𝐸𝐶𝑎50 +𝐶𝑎0 +2 𝐶(𝑡) +2 = +𝐸𝐶𝑎50 +(𝐶𝑎0)max +√𝑒𝐵(𝑙𝑟√2(𝜆−1)+1−𝑙0)−1 +and 𝐵 is a constant, (𝐶𝑎0)max is the maximum peak intracellular calcium con- +centration, 𝑙0 is the sarcomere length at which no active tension develops and 𝑙𝑟 +is the stress free sarcomere length. The function 𝐶(𝑡) is defined in one of two +ways. First it can be given as: +where +𝐶(𝑡) = +(1 − cos𝜔(𝑡)) +𝜔 = +𝑡0 +𝑡 − 𝑡0 + 𝑡𝑟 +𝑡𝑟 +⎧ +{ +{ +{ +⎨ +{ +{ +{ +⎩ +0 ≤ 𝑡 < 𝑡0 +𝑡0 ≤ 𝑡 < 𝑡0 + 𝑡𝑟 +𝑡0 + 𝑡𝑟 ≤ 𝑡 +and 𝑡𝑟 = 𝑚𝑙𝑅𝜆 + 𝑏. Secondly, it can also be given as a load curve. If a load curve +should be used its index must be given in ACT10. Note that all variables that +correspond to ω are neglected if a load curve is used. The active parameters on +Card 3 and 4 are interpreted as: +ACT1 ACT2 +ACT3 +ACT4 ACT5 ACT6 ACT7 ACT8 ACT9 ACT10 +𝑇max 𝐶𝑎0 +(𝐶𝑎0)max +𝑙0 +𝑡0 +𝑙𝑅 +LCID +References: +1. Freed AD., Einstein DR. and Vesely I., Invariant formulation for dispersed +transverse isotropy in aortic heart valves – An efficient means for modeling +fiber splay, Biomechan model Mechanobiol, 4, 100-117, 2005. +2. Guccione JM., Waldman LK., McCulloch AD., Mechanics of Active Contraction +in Cardiac Muscle: Part II – Cylindrical Models of the Systolic Left Ventricle, J. +Bio Mech, 115, 82-90, 1993. +*MAT_267 +This is Material Type 267. This is an advanced rubber-like model that is tailored for +glassy polymers and similar materials. It is based on Arruda´s eight chain model but +enhanced with non elastic properties. + Card 1 +1 +Variable +MID +Type +I +2 +RO +F +3 +K +F +4 +MU +F +Default +none +none +0.0 +0.0 + Card 2 +1 +Variable +YLD0 +Type +F +2 +FP +F +3 +GP +F +4 +HP +F +5 +N +I +0 +5 +LP +F +6 +7 +8 +MULL +VISPL +VISEL +I +0 +6 +MP +F +I +0 +7 +NP +F +I +0 +8 +PMU +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 3 +1 +Variable +M1 +2 +M2 +3 +M3 +4 +M4 +5 +6 +7 +8 +M5 +TIME +VCON +Type +F +F +F +F +F +F +F +Default +See +MULL +See +MULL +See +MULL +See +MULL +See +MULL +0.0 +9.0 +Variable +1 +Q1 +Type +F +*MAT_EIGHT_CHAIN_RUBBER +2 +B1 +F +3 +Q2 +F +4 +B2 +F +5 +Q3 +F +6 +B3 +F +7 +Q4 +F +8 +B4 +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 5 +Variable +1 +K1 +Type +F +2 +S1 +F +3 +K2 +F +4 +S2 +F +5 +K3 +F +6 +S3 +F +7 +8 +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 6 +1 +2 +Variable +AOPT +MACF +Type +F +F +3 +XP +F +4 +YP +F +5 +ZP +F +6 +A1 +F +7 +A2 +F +8 +A3 +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +.0.0 + Card 7 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +THETA +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Card 8-14 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TAUi +BETAi +Type +F +F +Default +0.0 +0.0 + VARIABLE +DESCRIPTION +MID +Material identification. A unique number must be specified +RO +K +MU +MULL +Mass density. +Bulk modulus. To get almost incompressible behavior set this to +one or two orders of magnitude higher than MU. Note that the +poisons ratio should be kept at a realistic value. +𝜐 = +3𝐾 − 2𝑀𝑈 +2(3𝐾 + 𝑀𝑈) +. +Shear modulus. MU is the product of the number of molecular +chains per unit volume (n), Boltzmann’s constant (k) and the +absolute temperature (T). Thus MU = nkT. +Parameter describing which softening algorithm that shall be +used. +EQ.1: Strain based Mullins effect from Qi and Boyce, see theory +section below for details +M1 = A (Qi recommends 3.5) +M2 = B (Qi recommends 18.0) +M3 = Z (Qi recommends 0.7) +M4 = vs (between 0 and 1 and less than vss) +M5 = vss (between 0 and 1 and greater than vs) +EQ.2: Energy based Mullins, a modified version of Roxburgh +and Ogden model. M1 > 0, M2 > 0 and M3 > 0 must be +set. See Theory section for details. +VISPL +*MAT_EIGHT_CHAIN_RUBBER +DESCRIPTION +Parameter describing which viscoplastic formulation that should +be used, see the theory section for details. +EQ.0: No viscoplasticity. +EQ.1: 2 parameters standard model, K1 and S1 must be set. +EQ.2: 6 parameters G’Sells model, K1,K2,K3,S1,S2 and S3 must +be set. +EQ.3: 4 parameters Strain hardening model, K1,K2,S1,S2 must +be set. +VISEL +Option for viscoelastic behavior, see the theory section for details. +EQ.0: No viscoelasticity. +EQ.1: Free energy formulation based on Holzapfel and Ogden. +EQ.2: Formulation based on stiffness ratios from Simo et al. +YLD0 +Initial yield stress. +EQ.0.0: No plasticity +GT.0.0: Initial yield stress: +seperataly. +Hardening +is +defined +LT.0.0: -YLD0 is taken as the load curve ID for the yield stress +versus effective plastic strain. +FP-NP +Parameters for Hill’s general yield surface. For von mises yield +criteria set FP = GP = HP = 0.5 and LP = MP = NP = 1.5. +PMU +Kinematic hardening parameter. It is usually equal to MU. +M1 - M5 +Mullins parameters +MULL.EQ.1: M1 - M5 are used +MULL.EQ.2: M1 - M3 are used. +TIME +VCON +A time filter that is used to smoothen out the time derivate of the +strain invariant over a TIME interval. Default is no smoothening +but a value 100*TIMESTEP is recommended. +A material constant for the volumetric part of the strain energy. +Default 9.0 but any value can be used to tailor the volumetric +response. For example -2. +VARIABLE +DESCRIPTION +Q1 - B4 +Voce hardening parameters +K1 - S3 +Viscoplastic parameters. +VISPL.EQ.1: K1 and S1 are used. +VISPL.EQ.2: K1, S1, K2, S2, K3 and S3 are used. +VISPL.EQ.3: K1, S1 and K2 are used. +AOPT +Material axes option for a more complete description. +EQ.0.0: Locally orthotropic with material axes defined by +element nodes 1, 2 and 4. +EQ.1.0: Locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the a-direction. +EQ.2.0: Globally orthotropic with material axes determined by +vectors defined below. +EQ.3.0: Locally orthotropic material axes determined by +rotating the material axes about the element normal by +and angle THETA. The angle is defined from the line +in the plane that is defined by the cross product of the +vector v with the element normal. The plane of a solid +is defined as the midsurface between the inner surface +and the outer surface defined by the first 4 nodes and +last 4 nodes. +EQ.4.0: Locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector v and an +originating point P. +MACF +Material axes change flag +EQ.1.0: No change (default) +EQ.2.0: Switch axes a and b +EQ.3.0: Switch axes a and c +EQ.4.0: Switch axes b and c +XP, YP, ZP +Define coordinates for point P for AOPT = 1 and 4 +A1, A2, A3 +Define components of vector a for AOPT = 2. +*MAT_EIGHT_CHAIN_RUBBER +DESCRIPTION +D1, D2, D3 +Define components of vector d for AOPT = 2 +V1, V2, V3 +Define components of vector v for AOPT = 3 and 4 +TAUi +Relaxation time. A maximum of 6 values can be used. +BETAi / +GAMMAi +VISEL.EQ.1: Dissipating energy factors. +VISEL.EQ.2: Gamma factors +Basic theory: +This model is based on the work done by Arruda and Boyce [1993], in particular +Arruda’s thesis [1992]. The eight chain rubber model is based on hyper elasticity and it +is formulated by using strain invariants. The strain softening is taken from work done +by Qi and Boyce [2004], where the strain energy used is defined as +Ψ = 𝑣𝑠𝜇 [√𝑁Λ𝑐𝛽 + 𝑁ln ( +sinh𝛽 +)] + Ψ2 = Ψ1 + Ψ2, +where the amplified chain stretch is given by Λ𝑐 = √𝑋(𝜆̅̅̅̅2 − 1) + 1and +𝛽 = 𝐿−1 +⎜⎛ Λ𝑐 +⎟⎞, +√𝑁⎠ +⎝ +where 𝜆̅̅̅̅2 = 𝐼1 3⁄ , 𝜇 is the initial modulus of the soft domain, N is the number of rigid +links between crosslinks of the soft domain region. 𝑋 = 1 + 𝐴(1 − 𝑣𝑠) + 𝐵(1 − 𝑣𝑠)2, is a +general polynomial describing the interaction between the soft and the hard phases (Qi +and Boyce [2004] and Tobin and Mullins [1957]). The compressible behavior is +described by the strain energy. +Ψ2 = +𝜈con +(𝜈conln𝐽 + +𝐽𝜈con +��� 1) +Where J is the determinant of the elastic deformation gradient Fe. The Cauchy stress is +then computed as: +𝝈 = +𝐅𝑒 +∂Ψ +∂𝐂𝑒 +𝑇 = +𝐅𝑒 +𝐅𝑒(𝐒𝟏 + 𝐒𝟐)𝐅𝑒 +𝑇 = +𝑣𝑠𝑋𝜇 +3𝐽 +√𝑁 +Λ𝑐 +𝐿−1 +⎜⎛ Λ𝑐 +√𝑁⎠ +⎝ +⎟⎞ (𝐁𝑒 − +𝐼1𝐈) + +2𝐾 +𝐽𝑣con +(1 − +𝐽𝑣con +) +where 𝐒𝟏 and 𝐒𝟐 are second Piola-Kirchhoff stresses based on Ψ1 and Ψ2 respectively. +Mullins effect: +Two models for the Mullins effect are implemented. +1. MULL = 1 +The strain softening is developed by the evolution law taken from Boyce 2004: +𝑣̇𝑠 = 𝑍(𝑣𝑠𝑠 − 𝑣𝑠) +√𝑁 − 1 +(√𝑁 − Λ𝑐 +max) +2 Λ̇ 𝑐 +max, +where Z is a parameter that characterizes the evolution in 𝑣𝑠 with increasing +Λ̇ 𝑐 +maxis the +maximum of Λ𝑐 from the past: +max. The parameter 𝑣𝑠𝑠 is the saturation value of 𝑣𝑠. Note that Λ̇ 𝑐 +Λ̇ 𝑐 +max = { +Λ𝑐 < Λ𝑐 +Λ̇ 𝑐 Λ𝑐 > Λ𝑐 +The structure now evolves with the deformation. The dissipation inequality +requires that the evolution of the structure is irreversible𝑣̇𝑠 ≥ 0. See Qi and +Boyce [2004]. +max +max. +2. MULL = 3 +The energy driven model based on Ogden and Roxburgh. When activated the +strain eergy is automatically transformed to a standard eight chain model. That +is, the variables Z, vs and X is automatically set to 0, 1 and 1 respectively. The +stress is multiplicative split of the true stress and the softening factor η. +𝜎̅̅̅̅̅ = 𝜂𝜎, 𝜂 = 1 − +𝑀1 +Viscoelasticity: +1. VISEL = 1 +erf ( +Ψ1 +max − Ψ1 +𝑀3 − 𝑀2Ψ1 +max). +The viscoelasticity is based on work dine by Holzapfel (2004) +𝐐̇ 𝛼 + +𝐐𝛼 +𝜏𝛼 += 2𝛽𝛼 +𝑑𝑡 +∂Ψ1 +∂𝐂𝑒 += 𝛽𝛼𝐒̇𝟏 +where 𝛼 is the number of viscoelastic terms (0, 1,…, 6). +2. VISEL = 2 +With this option the evolution is based on work done by Simo and Hughes +(2000). +𝐐̇ 𝛼 + +𝐐𝛼 +𝜏𝛼 += 2 +𝛾𝑎 +𝜏𝑎 +𝑑𝑡 +∂Ψ1 +∂𝐂𝑒 += +𝛾𝑎 +𝜏𝑎 +𝐒𝟏 +The the number of Prony terms is restricted to maximum 6 and τ > 0, γ > 0. +The Cauchy stress is obtained by a push forward operation on the total second +Piola-Kirchhoff stress. +σ = +𝐅𝑒𝐒𝐅𝑒 +𝑇. +Viscoplasticity: +The plasticity is based on the general Hills’ yield surface +2 = 𝐹(𝜎22 − 𝜎33)2 + 𝐺(𝜎33 − 𝜎11)2 + 𝐻(𝜎11 − 𝜎22)2 + 2𝐿𝜎12 +𝜎eff +2 + 2𝑀𝜎23 +2 +2 + 2𝑁𝜎13 +and the hardening is either based on a load curve ID (-YLD0) or an extended Voce +hardening +𝜎yld = 𝜎yld0 + 𝑄1(1 − 𝑒𝐵1𝜀̅) + 𝑄2(1 − 𝑒𝐵2𝜀̅) + 𝑄3(1 − 𝑒𝐵3𝜀̅) + 𝑄4(1 − 𝑒𝐵4𝜀̅). +The yield criterion is written +𝑓 = 𝜎eff − 𝜎yld ≤ 0. +Adding the viscoplastic phenomena, we simply add one evolution equation for the +effective plastic strain rate. Three different formulations is available. +1. VISPL = 1 +̇vp = ( +𝜀̅ +𝑆1 +) +. +𝐾1 +where K1 and S1 are viscoplastic material parameters. +2. VISPL = 2 +𝜀̇vp = +⎡ +⎢⎢ +⎣ +𝐾3 +𝐾1(1 − 𝑒−𝑆1(𝜀vp+𝐾2))𝑒𝑆2𝜀𝑣𝑝 +𝑆3 +⎤ +⎥⎥ +⎦ +Where K1, K2, K3, S1, S2 and S3 are viscoplastic parameters +3. VISPL = 3 +𝜀̇vp = ( +𝐾1 +𝑆1 +) +(𝜀vp + 𝐾2) +𝑆2 +Where K1, K2, S1 and S2 are viscoplastic parameters. +Kinematic hardening: +The back stress is calculated similar to the Cauchy stress above but without the +softening factors: +β = +𝜇𝑝 +3𝐽 +√𝑁 +Λ𝑐 +𝐿−1 +⎜⎛ Λ𝑐 +√𝑁⎠ +⎝ +⎟⎞ (𝐈 − +𝐼𝑝𝐂𝑝 +−1) +𝜇𝑝is a hardening material parameter (PMU). The total Piola-Kirchhoff stress is now +given by 𝐒∗ = 𝐒 − β and the total stress is given by a standard push forward operation +with the elastic deformation gradient. +Remarks: +1. The parameter PMU is usually taken the same as MU. +2. For the case of a dilute solution the Mullins parameter A should be equal to 3.5. +See Qi and Boyce [2004]. +3. For a system with well dispersed particles B should somewhere around 18. See +Qi and Boyce [2004]. +References: +Qi HJ., Boyce MC., Constitutive model for stretch-induced softening of stress-stretch +behavior of elastomeric materials, Journal of the Mechanics and Physics of Solids, 52, +2187-2205, 2004. +Arrude EM., Characterization of the strain hardening response of amorphous polymers, +PhD Thesis, MIT, 1992. +Mullins L., Tobin NR., Theoretical model for the elastic behavior of filler reinforced +vulcanized rubber, Rubber Chem. Technol., 30, 555-571, 1957. +Ogden RW. Roxburgh DG., A pseudo-elastic model for the Mullins effect in Filled +rubber., Proc. R. Soc. Lond. A., 455, 2861-2877, 1999. +Simo JC., Hughes TJR., Computational Inelasticity, Springer, New York, 2000. +Holzapfel GA., Nonlinear Solid Mechanics, Wiley, New-York, 2000. +*MAT_BERGSTROM_BOYCE_RUBBER +This is material type 269. This is a rubber model based on the Arruda and Boyce (1993) +chain model accompanied with a viscoelastic contribution according to Bergström and +Boyce (1998). The viscoelastic treatment is based on the physical response of a single +entangled chain in an embedded polymer gel matrix and the implementation is based +on Dal and Kaliske (2009). This model is only available for solid elements. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +K +F +4 +G +F +5 +GV +F +6 +N +F +7 +NV +F +8 +Default +none +none +none +none +none +none +none + Card 2 +Variable +Type +1 +C +F +2 +M +F +3 +4 +5 +6 +7 +8 +GAM0 +TAUH +F +F +Default +none +none +none +none + VARIABLE +DESCRIPTION +MID +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +K +G +GV +N +Elastic bulk modulus +Elastic shear modulus +Viscoelastic shear modulus +Elastic segment number +VARIABLE +DESCRIPTION +NV +Viscoelastic segment number +C +M +Inelastic strain exponent, should be less than zero +Inelastic stress exponent +TAUH +Reference Kirchhoff stress +Remarks: +The deviatoric Kirchhoff stress for this model is the sum of an elastic and viscoelastic +part according to +The elastic part is governed by the Arruda-Boyce strain energy potential resulting in the +following expression (after a Pade approximation of the Langevin function) +τ̅̅̅̅̅ = τ𝑒 + τ𝑣 +τ𝑒 = +3 − 𝜆𝑟 +1 − 𝜆𝑟 +2 (𝐛̅ − +𝑇𝑟(𝐛̅ ) +𝐈) +Here G is the elastic shear modulus, +is the unimodular left Cauchy-Green tensor, and +𝐛̅ = 𝐽−2/3𝐅𝐅𝑇 +𝐽 = det 𝐅 +2 = +𝜆𝑟 +𝑇𝑟(𝐛̅ ) +3𝑁 +is the relative network stretch. +The viscoelastic stress is based on a multiplicative split of the unimodular deformation +gradient into unimodular elastic and inelastic parts, respectively, +and we define +𝐽−1/3𝐅 = 𝐅𝑒𝐅𝑖 +𝑇 +𝐛𝑒 = 𝐅𝑒𝐅𝑒 +to be the elastic left Cauchy-Green tensor. The viscoelastic stress is given as +where +τ𝑣 = +𝐺𝑣 +3 − 𝜆𝑣 +2 (𝐛𝑒 − +1 − 𝜆𝑣 +𝑇𝑟(𝐛𝑒) +𝐈) +2 = +𝜆𝑣 +𝑇𝑟(𝐛𝑒) +3𝑁𝑣 +is the relative network stretch for the viscoelastic part. The evolution of the elastic left +Cauchy-Green tensor can be written +where the inelastic rate-of-deformation tensor is given as +𝐛̇ +𝑒 = 𝐋̅ 𝐛𝑒 + 𝐛𝑒𝐋̅ 𝑇 − 2𝐃𝑖𝐛𝑒 +and +𝐃𝑖 = 𝛾̇0(𝜆𝑖 − 0.999)𝑐 +⎜⎛∥τ𝑣∥ +⎟⎞ +𝜏̂√2⎠ +⎝ +𝑚 τ𝑣 +∥τ𝑣∥ +𝐋̅ = 𝐋 − +𝑇𝑟(𝐋) +𝐈 +is the deviatoric velocity gradient. The stretch of a single chain relaxing in a polymer is +linked to the inelastic right Cauchy-Green tensor as +2 = +𝜆𝑖 +𝑇𝐅𝑖) +𝑇𝑟(𝐅𝑖 +≥ 1, +and this stretch is available as the plastic strain variable in the post processing of this +material. The volumetric part is elastic and governed by the bulk modulus, the +pressure for this model is given as +𝑝 = 𝐾(𝐽−1 − 1). +*MAT_270 +This is material type 270. This is a thermo-elastic-plastic model with kinematic +hardening that allows for material creation as well as annealing triggered by +temperature. The acronym CWM stands for Computational Welding Mechanics, +Lindström (2013, 2015), and the model is intended to be used for simulating multistage +weld processes. This model is available for solid and shell elements. + Card 1 +1 +Variable +MID +2 +RO +3 +4 +5 +6 +7 +8 +LCEM +LCPR +LCSY +LCHR +LCAT +BETA +Type +A8 +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +None + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TASTART +TAEND +TLSTART +TLEND +EGHOST +PGHOST AGHOST +Type +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +Optional Phase Change Card. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +T2PHASE T1PHASE +Type +F +F +Default optional optional + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Material density +LCEM +Load curve for Young’s modulus as function of temperature +LCPR +LCSY +LCHR +LCAT +Load curve for Poisson’s ratio as function of temperature +Load curve or table for yield stress. +GT.0: Yield stress is a load curve as function of temperature. +LT.0: |LCSY| is a table of yield curves for different tempera- +tures. Each yield curve is a function of plastic strain. +Load curve for hardening modulus as function of temperature. +LCHR is not used for LCSY.LT.0. Hardening modulus is then +calculated from yield curve slope. +Load curve (or table) for thermal expansion coefficient as function +of temperature (and maximum temperature up to current time). +In the case of a table, load curves are listed according to their +maximum temperature. +BETA +Fraction isotropic hardening between 0 and 1 +EQ.0: Kinematic hardening +EQ.1: Isotropic hardening +TASTART +Annealing temperature start +TAEND +Annealing temperature end +TLSTART +Birth temperature start +TLEND +Birth temperature end +EGHOST +Young’s modulus for ghost (quiet) material +PGHOST +Poisson’s ratio for ghost (quiet) material +AGHOST +Thermal expansion coefficient for ghost (quiet) material +T2PHASE +Temperature at which phase change commences +T1PHASE +Temperature at which phase change ends +*MAT_270 +This material is initially in a quiet state, sometimes referred to as a ghost material. In +this state the material has the thermo-elastic properties defined by the quiet Young’s +modulus, quiet Poisson’s ratio and quiet thermal expansion coefficient. These should +represent void, i.e., the Young’s modulus should be small enough to not influence the +surroundings but large enough to avoid numerical problems. A quiet material stress +should never reach the yield point. When the temperature reaches the birth +temperature, a history variable representing the indicator of the welding material is +incremented. This variable follows +𝛾(𝑡) = min (1, max [0, +𝑇max − 𝑇𝑙 +end − 𝑇𝑙 +𝑇𝑙 +𝑇(𝑠). This parameter is available as history variable 9 in the output +]) +start +start +where 𝑇max = max +𝑠≤𝑡 +database. The effective thermo-elastic material properties are interpolated as +𝐸 = 𝐸(𝑇)𝛾 + 𝐸quiet(1 − 𝛾) +𝜈 = 𝜈(𝑇)𝛾 + 𝜈quiet(1 − 𝛾) +𝛼 = 𝛼(𝑇, 𝑇max)𝛾 + 𝛼quiet(1 − 𝛾) +where 𝐸, 𝜈, and 𝛼 are the Young’s modulus, Poisson’s ratio and thermal expansion +coefficient, respectively. Here, the thermal expansion coefficient is either a temperature +dependent curve, or a collection of temperature dependent curves, ordered in a table +according to maximum temperature 𝑇max. The stress update then follows a classical +isotropic associative thermo-elastic-plastic approach with kinematic hardening that is +summarized in the following. The explicit temperature dependence is sometimes +dropped for the sake of clarity. +The stress evolution is given as +where 𝐂 is the effective elastic constitutive tensor and +σ̇ = 𝐂(ε̇ − ε̇𝑝 − ε̇𝑇) +ε̇𝑇 = 𝛼𝑇̇𝐈 +ε̇𝑝 = 𝜀̇𝑝 +𝐬 − κ +𝜎̅̅̅̅̅ +are the thermal and plastic strain rates, respectively. The latter expression includes the +deviatoric stress +the back stress κ and the effective stress +𝐬 = 𝛔 − +Tr(𝛔)𝐈, +𝜎̅̅̅̅̅ = √ +(𝐬 − κ): (𝐬 − κ) +that are involved in the plastic equations. To this end, the effective yield stress is given +as +𝜎𝑌 = 𝜎𝑌(𝑇) + 𝛽𝐻(𝑇)𝜀𝑝 +and plastic strains evolve when the effective stress exceeds this value. The back stress +evolves as +κ̇ = (1 − 𝛽)𝐻(𝑇)𝜀̇𝑝 +𝐬 − κ +𝜎̅̅̅̅̅ +where 𝜀̇𝑝 is the rate of effective plastic strain that follows from consistency equations. +When the temperature reaches the start annealing temperature, the material starts +assuming its virgin properties. Beyond the start annealing temperature it behaves as an +ideal elastic-plastic material but with no evolution of plastic strains. The resetting of +effective plastic properties in the annealing temperature interval is done by modifying +the effective plastic strain and back stress before the stress update as +𝑛+1 = 𝜀𝑝 +𝜀𝑝 +𝑛max [0, min (1, +κ𝑛+1 = κ𝑛max [0, min (1, +𝑇𝑎 +end +𝑇 − 𝑇𝑎 +start − 𝑇𝑎 +end +𝑇 − 𝑇𝑎 +start − 𝑇𝑎 +𝑇𝑎 +)] +end +)] +end +The optional Card 3 is used to set history variable 11, which is the average temperature +rate by which the temperature has gone from T2PHASE to T1PHASE. To fringe this +variable the range should be set to positive values since it is during the simulation +temporarily used to store the time when the material has reached temperature +T2PHASE and is then stored as a negative value. A strictly positive value means that +the material has reached temperature T2PHASE and gone down to T1PHASE and the +history variable is (T2PHASE − T1PHASE) (T1 − T2) +, where T2 is the time when +temperature T2PHASE is reached and T1 is the time when temperature T1PHASE is +reached. Note that T2PHASE > T1PHASE and T1 > T2. A value of zero means that the +element has not yet reached temperature T2PHASE. A strictly negative value means +that the element has reached temperature T2PHASE but not yet T1PHASE. +⁄ +History variable Description +1-6 Back stress +7 Temperature at last time step +8 Yield indicator: 1 if yielding, else 0 +9 Welding material indicator: 0 for ghost material, else 1 +10 Maximum temperature reached +11 Average temperature rate going from T2PHASE to T1PHASE +*MAT_271 +This is material type 271. This model is used to analyze the compaction and sintering of +cemented carbides and the model is based on the works of Brandt (1998). This material +is only available for solid elements. + Card 1 +1 +Variable +MID +2 +RO +3 +4 +5 +6 +7 +8 +P11 +P22 +P33 +P12 +P23 +P13 +Type +A8 +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none + Card 2 +Variable +1 +E0 +2 +LCK +Type +F +F +3 +PR +F +4 +5 +6 +LCX +LCY +LCC +F +F +F +7 +L +F +8 +R +F +Default +none +none +none +none +none +none +none +none + Card 3 +Variable +1 +CA +Type +F +2 +CD +F +3 +CV +F +4 +P +F +5 +6 +7 +8 +LCH +LCFI +SINT +TZRO +F +F +F +F +Default +none +none +none +none +none +none +0.0 +none +Sintering Card 1. Additional card for SINT = 1. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCFK +LCFS2 +DV1 +DV2 +DS1 +DS2 +OMEGA +RGAS +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +Sintering Card 2. Additional card for SINT = 1. + Card 5 +1 +2 +3 +4 +5 +6 +Variable +LCPR +LCFS3 +LCTAU +ALPHA +LCFS1 +GAMMA +Type +F +F +F +F +F +F +7 +L0 +F +8 +LCFKS +F +Default +none +none +none +none +none +none +none +none + VARIABLE +DESCRIPTION +MID +RO +PIJ +E0 +LCK +PR +LCX +LCY +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Initial compactness tensor Pij +Initial anisotropy variable e (value between 1 and 2) +Load curve for bulk modulus K as function of relative density d +Poisson’s ratio +Load curve for hydrostatic compressive yield X as function of +relative density d +Load curve for uniaxial compressive yield Y as function of +relative density d +LCC +Load curve for shear yield C0 as function of relative density d +L +R +CA +CD +CV +P +LCH +LCFI +Yield surface parameter L relating hydrostatic compressive yield +to point on hydrostatic axis with maximum strength +Yield surface parameter R governing the shape of the yield +surface +Hardening parameter ca +Hardening parameter cd +Hardening parameter cv +Hardening exponent p +Load curve giving back stress parameter H as function of +hardening parameter e. +Load curve giving plastic strain evolution angle ϕ as function of +relative volumetric stress. +SINT +Activate sintering +EQ.0.0: Sintering off +EQ.1.0: Sintering on +Absolute zero temperature T0 +Load curve fK for viscous compliance as function of relative +density d +Load curve fS2 for viscous compliance as function of temperature +T +Volume diffusion coefficient dV1 +Volume diffusion coefficient dV2 +Surface diffusion coefficient dS1 +Surface diffusion coefficient dS2 +TZRO +LCFK +LCFS2 +DV1 +DV2 +DS1 +DS2 +OMEGA +Blending parameter ω +RGAS +LCPR +Universal gas constant Rgas +Load curve for viscous Poisson’s ratio ν as function of relative +density d +LCFS3 +LCTAU +ALPHA +LCFS1 +Load curve fS3 for evolution of mobility factor as function of +temperature T +Load curve for relaxation time τ as function of temperature T +Thermal expansion coefficient α +Load curve fS1 for sintering stress scaling as function of relative +density d +GAMMA +Surface energy density γ affecting sintering stress +L0 +Grain size l0 affecting sintering stress +LCFKS +Load curve fKS scaling bulk modulus as function of temperature +T +Remarks: +This model is intended to be used in two stages. During the first step the compaction of +a powder specimen is simulated after which the results are dumped to file, and in a +subsequent step the model is restarted for simulating sintering of the compacted +specimen. In the following, an overview of the two different models is given, for a +detailed description we refer to Brandt (1998). The progressive stiffening in the material +during compaction makes it more or less necessary to run double precision and with +constraint contacts to avoid instabilities, unfortunately this currently limitates the use of +this material to the smp version of LS-DYNA. +The powder compaction model makes use of a multiplicative split of the deformation +gradient into a plastic and elastic part according to +𝐅 = 𝐅𝑒𝐅𝑝 +where the plastic deformation gradient maps the initial reference configuration to an +intermediate relaxed configuration +𝛿𝐱̃ = 𝐅𝑝𝛿𝐗 +and subsequently the elastic part maps this onto the current loaded configuration +𝛿𝐱 = 𝐅𝑒𝛿𝐱̃ +The compactness tensor is introduced that maps the intermediate configuration onto a +virtual fully compacted configuration +and we define the relative density as +𝛿𝐱̅ = 𝐏𝛿𝐱̃ +𝑑 = det𝐏 = +𝜌̅ +where 𝜌 and 𝜌̅ denotes the current and fully compacted density, respectively. The +elastic properties depend highly on the relative density through the bulk modulus 𝐾(𝑑) +but the Poisson’s ratio is assumed constant. +Y(d) +nε +φ(J1/X(d)) +nε +C0(d) +Y(d) +max=(L- +-J1 = σVM +-X(d)L +-J1 +- +X(d) +The yield surface is represented by two functions in the Rendulic plane according to +𝜎𝑌(𝑑) = +⎧𝐶0(𝑑) − 𝐶1(𝑑)𝐽1 − 𝐶2(𝑑)𝐽1 +{{ +√[(𝐿 − 1)𝑋(𝑑)]2 − [𝐽1 − 𝐿𝑋(𝑑)]2 +⎨ +{{ +⎩ +𝐽1 ≥ 𝐿𝑋(𝑑) +𝐽1 < 𝐿𝑋(𝑑) +and is in this way capped in both compression and tension, here +𝐽1 = 3𝜎 𝑚 = 𝑇𝑟(σ). +The polynomial coefficients in the expression above are chosen to give continuity at +𝐽1 = 𝐿𝑋(𝑑) and to give the uniaxial compressive strength Y(d). Yielding is assumed to +occur when the equivalent stress (note the definition) equals the yield stress +where +𝜎eq = +𝜎𝑉𝑀 +√3 += √ +𝐬: 𝐬 ≤ 𝜎𝑌(𝑑) +𝐬 = σ − 𝜎 𝑚𝐈 +⏟⏟⏟⏟⏟ +σ𝑑 +− κ +in which the last term is the back stress to be dealt with below. The yield surface does +not depend on the third stress invariant. The plastic flow is non-assosiated and its +direction is given by +where +𝐧𝜀 = ( +cos𝜑 −sin𝜑 + sin𝜑 cos𝜑 +) 𝐧 +∂𝜎𝑌 +⎟⎟⎞ +∂𝐽1 +1 ⎠ +𝐧 = +𝜎𝑌(𝑑) +⎜⎜⎛ +𝜎max ⎝ +is the normal to the yield surface as depicted in the Rendulic plane above (note the sign +of J1). The angle φ is a function of and defined only for positive values of the relative +volumetric stress J1/X(d)>0, for negative values φ is determined internally to achieve +smoothness in the plastic flow direction and such that avoid numerical problems at the +tensile cap point. The above equations are for illustrative purposes, from now on the +plastic flow direction is generalized to a second order tensor. The plastic flow rule is +then +ε̇𝑝 = 𝜆̇𝐧𝜀, +𝑚 = +𝜀̇𝑝 +𝑇𝑟(ε̇𝑝), +𝑑 = ε̇𝑝 − 𝜀̇𝑝 +ε̇𝑝 +𝑚𝐈 +The evolution of the compactness tensor is directly related to the evolution of plastic +strain as +𝐏̇ = − +(ε̇𝑝𝐏 + 𝐏ε̇𝑝) +and thus the relative density is given by +𝑑 ̇= −3𝜀̇𝑝 +𝑚𝑑 . +The back stress is assumed coaxial with the deviatoric part of the compactness tensor +and given by +κ = 𝐽1𝐻(𝑒) (𝐏 − +𝑇𝑟(𝐏) +𝐈) +where e is a measure of intensity of anisotropy. This takes a value between 1 and 2 and +evolves with plastic strain and plastic work according to +𝒆 ̇ = 𝑐𝑎√ +where +𝑑: 𝛆̇𝑝 +𝛆̇𝑝 +𝑑 − 𝑐𝑣𝐽1𝜀̇𝑝 +𝑚𝑊(𝑑, 𝐽1) + 𝑐𝑑𝛆̇𝑝 +𝑑: 𝛔𝑊(𝑑, 𝐽1) +𝑊(𝑑, 𝐽1) = − [ +𝐽1 +𝑋(𝑑) +] +∫ +𝑑0 +𝑋(𝜉 ) +3𝜉 +𝑑𝜉 +and d0 is the density in the initial uncompressed configuration. The stress update is +completed by the rate equation of stress +where C(d) is the elastic constitutive matrix. +𝝈̇ = 𝐂(𝑑): (ε̇ − ε̇𝑝) +The sintering model is a thermo and viscoelastic model where the evolution of the mean +and deviatoric stress can be written as +𝜎̇ 𝑚 = 3𝐾𝑠(𝜀̇𝑚 − 𝜀̇𝑇 − 𝜀̇𝑝 +𝑚) +σ̇ 𝑑 = 2𝐺𝑠(ε̇𝑑 − ε̇𝑝 +𝑑) +The thermal strain rate is given by the thermal expansion coefficient as +𝜀̇𝑇 = 𝛼𝑇̇ +and the bulk and shear modulus are the same as for the compaction model with the +exception that they are scaled by a temperature curve +𝐾𝑠 = 𝑓𝐾𝑆(𝑇)𝐾(𝑑) +𝐺𝑠 = +3(1 − 2𝜈) +2(1 + 𝜈) +𝐾𝑠 +The inelastic strain rates are different from the compaction model and is here given by +ε̇𝑝 = +𝝈𝑑 +2𝐺𝑣 + +𝜎 𝑚 − 𝜎 𝑠 +3𝐾𝑣 +𝐈 +which results in a viscoelastic behavior depending on the viscous compliance and +sintering stress. The viscous bulk compliance can be written +𝐾𝑣 = 3𝑓𝐾(𝑑) {𝑑𝑉1exp [− +𝑑𝑉2 +𝑅𝑔𝑎𝑠(𝑇 − 𝑇0) +] + 𝜔𝑑𝑆1exp [− +𝑑𝑆2 +𝑅𝑔𝑎𝑠(𝑇 − 𝑇0) +]} [1 + 𝑓𝑆2(𝑇)𝜉 ] +from which the viscous shear compliance is modified with aid of the viscous Poisson’s +ratio +𝐺𝑣 = +2[1 + 𝜈𝑣(𝑑)] +3[1 − 2𝜈𝑣(𝑑)] +𝐾𝑣 . +The mobility factor ξ evolves with temperature according to +and the sintering stress is given as +𝜉 ̇ = +𝑓𝑆3(𝑇)𝑇̇ − 𝜉 +𝜏(𝑇) +𝜎 𝑠 = 𝑓𝑆1(𝑑) +𝑙0 + . +All this is accompanied with, again, the evolution of relative density given as +𝑑 ̇= −3𝜀̇𝑝 +𝑚𝑑 +*MAT_RHT +This is material type 272. This model is used to analyze concrete structures subjected to +impulsive loadings, see Riedel et.al. (1999) and Riedel (2004). + Card 1 +1 +2 +3 +4 +5 +Varriable +MID +RO +SHEAR +ONEMPA +EPSF +Type +A8 + Card 2 +Variable +Type +1 +A +F + Card 3 +1 +F +2 +N +F +2 +Varriable +E0C +E0T +Type +F + Card 4 +1 +F +2 +Variable +GC* +GT* +Type +F +F + Card 5 +1 +Variable +GAMMA +Type +F +2 +A1 +F +F +3 +FC +F +3 +EC +F +3 +XI +F +3 +A2 +F +6 +B0 +F +6 +Q0 +F +6 +7 +B1 +F +7 +B +F +7 +F +4 +F +5 +FS* +FT* +F +5 +BETAC +BETAT +PTF +F +5 +D2 +F +5 +F +6 +EPM +F +6 +F +7 +AF +F +7 +F +4 +ET +F +4 +D1 +F +4 +A3 +F +8 +T1 +F +8 +T2 +F +8 +8 +NF +F +8 +PEL +PCO +NP +ALPHA0 +F +F +F +MID +RO +SHEAR +ONEMPA +*MAT_272 +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Elastic shear modulus +Unit conversion factor defining 1 Mpa in the pressure units used. +It can also be used for automatic generation of material +parameters for a given compressive strength. +EQ.0: Defaults to 1.0 +EQ.-1: Parameters generated in m, s and kg (Pa) +EQ.-2: Parameters generated in mm, s and tonne (MPa) +EQ.-3: Parameters generated in mm, ms and kg (GPa) +EQ.-4: Parameters generated in in, s and dozens of slugs (psi) +EQ.-5: Parameters generated in mm, ms and g (MPa) +EQ.-6: Parameters generated in cm, μs and g (Mbar) +EQ.-7: Parameters generated in mm, ms and mg (kPa) +EPSF +Eroding plastic strain (default is 2.0) +B0 +B1 +T1 +A +N +FC +FS* +FT* +Q0 +B +T2 +Parameter for polynomial EOS +Parameter for polynomial EOS +Parameter for polynomial EOS +Failure surface parameter 𝐴 +Failure surface parameter 𝑁 +Compressive strength. +Relative shear strength +Relative tensile strength +Lode angle dependence factor +Lode angle dependence factor +Parameter for polynomial EOS +VARIABLE +DESCRIPTION +E0C +E0T +EC +ET +BETAC +BETAT +PTF +GC* +GT* +XI +D1 +D2 +EPM +AF +NF +Reference compressive strain rate +Reference tensile strain rate +Break compressive strain rate +Break tensile strain rate +Compressive strain rate dependence exponent (optional) +Tensile strain rate dependence exponent (optional) +Pressure influence on plastic flow in tension (default is 0.001) +Compressive yield surface parameter +Tensile yield surface parameter +Shear modulus reduction factor +Damage parameter +Damage parameter +Minimum damaged residual strain +Residual surface parameter +Residual surface parameter +GAMMA +Gruneisen gamma +A1 +A2 +A3 +PEL +PCO +NP +Hugoniot polynomial coefficient +Hugoniot polynomial coefficient +Hugoniot polynomial coefficient +Crush pressure +Compaction pressure +Porosity exponent +ALPHA +Initial porosity +*MAT_272 +In the RHT model, the shear and pressure part is coupled in which the pressure is +described by the Mie-Gruneisen form with a polynomial Hugoniot curve and a p-α +compaction relation. For the compaction model, we define a history variable +representing the porosity 𝛼 that is initialized to 𝛼0 > 1. This variable represents the +current fraction of density between the matrix material and the porous concrete and +will decrease with increasing pressure, i.e., the reference density is expressed as 𝛼𝜌. The +evolution of this variable is given as +𝛼(𝑡) = max +⎜⎛1, min +⎝ +⎡1 + (𝛼0 − 1) ( +⎢ +⎣ +where 𝑝(𝑡) indicates the pressure at time t. This expression also involves the initial pore +crush pressure 𝑝el, compaction pressure 𝑝comp and porosity exponent 𝑁. For later use, +we define the cap pressure, or current pore crush pressure, as +𝛼0, min𝑠≤𝑡 +⎟⎞ +⎠ +) +𝑝comp − 𝑝(𝑠) +𝑝comp − 𝑝el +}⎫ +⎤ +⎥ +⎭}⎬ +⎦ +{⎧ +⎩{⎨ +𝑝𝑐 = 𝑝comp − (𝑝comp − 𝑝el) ( +1/𝑁 +) +𝛼 − 1 +𝛼0 − 1 +The remainder of the pressure (EOS) model is given in terms of the porous density 𝜌 +and specific internal energy 𝑒 (wrt the porous density). Depending on user inputs, it is +either governed by (𝐵0 > 0) +𝑝(𝜌, 𝑒) = +(𝐵0 + 𝐵1𝜂)𝛼𝜌𝑒 + 𝐴1𝜂 + 𝐴2𝜂2 + 𝐴3𝜂3 𝜂 > 0 +{ +𝐵0𝛼𝜌𝑒 + 𝑇1𝜂 + 𝑇2𝜂2 +𝜂 < 0 +or (𝐵0 = 0) +together with +𝑝(𝜌, 𝑒) = Γ𝜌𝑒 + +𝑝𝐻(𝜂) = 𝐴1𝜂 + 𝐴2𝜂2 + 𝐴3𝜂3 +𝑝𝐻(𝜂) [1 − +Γ𝜂] +𝜂(𝜌) = +𝛼𝜌 +𝛼0𝜌0 +− 1 . +For the shear strength description we use +𝑝∗ = +𝑓𝑐 + . +as the pressure normalized with the compressive strength parameter. We also use 𝐬 to +denote the deviatoric stress tensor and 𝜀̇𝑝 the plastic strain rate. The effective plastic +strain is thus denoted ε𝑝 and can be viewed as such in the post processor of choice. +For a given stress state and rate of loading, the elastic-plastic yield surface for the RHT +model is given by +𝜎𝑦(𝑝∗, 𝐬, 𝜀̇𝑝, 𝜀𝑝 +∗) = 𝑓𝑐𝜎𝑦 +∗(𝑝∗, 𝐹𝑟(𝜀̇𝑝, 𝑝∗), 𝜀𝑝 +∗)𝑅3(𝜃, 𝑝∗) +and is the composition of two functions and the compressive strength parameter 𝑓𝑐. The +first describes the pressure dependence for principal stress conditions 𝜎1 < 𝜎2 = 𝜎3 and +is expressed in terms of a failure surface and normalized plastic strain as +𝜎𝑦 +∗(𝑝∗, 𝐹𝑟, 𝜀𝑝 +∗) = 𝜎𝑓 +∗ ( +𝑝∗ +, 𝐹𝑟) 𝛾 +with +The failure surface is given as +𝛾 = 𝜀𝑝 +∗ + (1 − 𝜀𝑝 +∗)𝐹𝑒𝐹𝑐 . +∗(𝑝∗, 𝐹𝑟) = +𝜎𝑓 +⎡𝑝∗ − +⎢ +⎣ +𝐹𝑟 ++ ( +𝐹𝑟 +−1 +𝑛⁄ +) +⎤ +⎥ +⎦ ++ 3𝑝∗ (1 − +∗ +𝑓𝑠 +𝑄1 +) +− 3𝑝∗ ( +𝑄2 +− +∗ +𝑓𝑠 +𝑄1𝑓𝑡 +∗) +∗ +𝐹𝑟𝑓𝑠 +𝑄1 +∗ +𝐹𝑟𝑓𝑠 +𝑄1 +⎧ +{ +{ +{ +{ +{ +{ +{ +{ +{ +{ +{ +⎨ +{ +{ +{ +{ +{ +{ +{ +{ +{ +{ +{ +⎩ +3𝑝∗ ≥ 𝐹𝑟 +𝐹𝑟 > 3𝑝∗ ≥ 0 +∗ +0 > 3𝑝∗ > 3𝑝𝑡 +3𝑝𝑡 +∗ > 3𝑝∗ +∗ = +in which 𝑝𝑡 +factor and +𝐹𝑟𝑄2𝑓𝑠 +∗ +∗𝑓𝑡 +∗−𝑄2𝑓𝑠 +∗) +3(𝑄1𝑓𝑡 + is the failure cut-off pressure, 𝐹𝑟 is a dynamic increment +𝑄1 = 𝑅3 ( +, 0) +𝑄2 = 𝑄(𝑝∗) +∗ are the tensile and shear strength of the concrete relative +In these expressions, 𝑓𝑡 +to the compressive strength 𝑓𝑐 and the Q values are introduced to account for the tensile +and shear meridian dependence. Further details are given in the following. +∗ and 𝑓𝑠 +To describe reduced strength on shear and tensile meridian the factor +𝑅3(𝜃, 𝑝∗) = +2(1 − 𝑄2)cos𝜃 + (2𝑄 − 1)√4(1 − 𝑄2)cos2𝜃 + 5𝑄2 − 4𝑄 +4(1 − 𝑄2)cos2𝜃 + (1 − 2𝑄)2 +is introduced, where 𝜃 is the Lode angle given by the deviatoric stress tensor s as +cos3𝜃 = +27 det(𝐬) +2𝜎̅̅̅̅̅(𝐬)3 +𝜎̅̅̅̅̅(𝐬) = √ +𝐬: 𝐬 . +The maximum reduction in strength is given as a function of relative pressure +Finally, the strain rate dependence is given by +𝑄 = 𝑄(𝑝∗) = 𝑄0 + 𝐵𝑝∗ . +𝐹𝑟(𝜀̇𝑝, 𝑝∗) = +in which +𝑐 − +𝐹𝑟 +⎧ +{ +{ +⎨ +{ +{ +⎩ +𝐹𝑟 +3𝑝∗ − 𝐹𝑟 +∗ (𝐹𝑟 +𝑐 + 𝐹𝑟 +𝑡𝑓𝑡 +𝐹𝑟 +𝐹𝑟 +𝑡 − 𝐹𝑟 +𝑐) 𝐹𝑟 +∗ +𝑐 > 3𝑝∗ ≥ −𝐹𝑟 +𝑡𝑓𝑡 +3𝑝∗ ≥ 𝐹𝑟 +𝑡𝑓𝑡 +−𝐹𝑟 +∗ > 3𝑝∗ +𝑡(𝜀̇𝑝) = +𝐹𝑟 +⎧ +{{{ +⎨ +{{{ +⎩ +⎜⎜⎛ 𝜀̇𝑝 +𝑡⁄ +𝜀̇0 +⎝ +𝛾𝑐 +𝛽𝑐 +𝑡⁄ +⎟⎟⎞ +⎠ +√𝜀̇𝑝 +𝑡⁄ +𝜀̇𝑝 +≥ 𝜀̇𝑝 +𝑡⁄ +𝜀̇𝑝 > 𝜀̇𝑝 + . +The parameters involved in these expressions are given as (𝑓𝑐 is in MPa below) +𝛽𝑐 = +𝛽𝑡 = +20 + 3𝑓𝑐 +20 + 𝑓𝑐 +and 𝛾𝑐/𝑡 is determined from continuity requirements, but it is also possible to choose the +rate parameters via inputs. +The elastic strength parameter used above is given by +𝐹𝑒(𝑝∗) = +⎧ +{ +{ +{ +⎨ +{ +{ +{ +⎩ +∗ − +𝑔𝑐 +∗ +𝑔𝑐 +3𝑝∗ − 𝐹𝑟 +∗ +𝑐𝑔𝑐 +∗𝑓𝑡 +∗ + 𝐹𝑟 +𝑡𝑔𝑡 +𝑐𝑔𝑐 +𝐹𝑟 +∗ +𝑔𝑡 +3𝑝∗ ≥ 𝐹𝑟 +∗ +𝑐𝑔𝑐 +∗ (𝑔𝑡 +∗ − 𝑔𝑐 +∗) 𝐹𝑟 +𝑐𝑔𝑐 +∗ > 3𝑝∗ ≥ −𝐹𝑟 +𝑡𝑔𝑡 +∗ +∗𝑓𝑡 +−𝐹𝑟 +𝑡𝑔𝑡 +∗𝑓𝑡 +∗ > 3𝑝∗ +while the cap of the yield surface is represented by +𝐹𝑐(𝑝∗) = +𝑝∗ ≥ 𝑝𝑐 +∗ +√1 − ( +∗ +𝑝∗ − 𝑝𝑢 +∗ ) +∗ − 𝑝𝑢 +𝑝𝑐 +∗ > 𝑝∗ ≥ 𝑝𝑢 +∗ +𝑝𝑐 +∗ > 𝑝∗ +𝑝𝑢 +⎧ +{{{ +⎨ +{{{ +⎩ +where +𝑝𝑐 +𝑓𝑐 ++ +∗ = +𝑝𝑐 +∗ +𝑐𝑔𝑐 +𝐹𝑟 +𝐺∗𝜀𝑝 +𝑓𝑐 +∗ = +𝑝𝑢 +The hardening behavior is described linearly with respect to the plastic strain, where +, 1 +∗ = min +𝜀𝑝 +𝜀𝑝 +⎟⎞ +⎜⎛ +𝜀𝑝 +⎠ +⎝ +∗)(1 − 𝐹𝑒𝐹𝑐) +𝜎𝑦(𝑝∗, 𝐬, 𝜀̇𝑝, 𝜀𝑝 +𝛾3𝐺∗ +ℎ = +𝜀𝑝 +here +𝐺∗ = 𝜉𝐺 +where 𝐺 is the shear modulus of the virgin material and 𝜉 is a reduction factor +representing the hardening in the model. +When hardening states reach the ultimate strength of the concrete on the failure surface, +damage is accumulated during further inelastic loading controlled by plastic strain. To +this end, the plastic strain at failure is given as +𝑓 = +𝜀𝑝 +⎧ +{{{{ +{{{{ +⎨ +⎩ +𝐷1[𝑝∗ − (1 − 𝐷)𝑝𝑡 +∗]𝐷2 +𝑝∗ ≥ (1 − 𝐷)𝑝𝑡 +∗ + ( +𝜀𝑝 +(1 − 𝐷)𝑝𝑡 +∗ + ( +𝜀���� +𝐷1 +) +⁄ +𝐷2 +) +𝜀𝑝 +𝐷1 +⁄ +𝐷2 + > 𝑝∗ +The damage parameter is accumulated with plastic strain according to +𝜀𝑝 +𝐷 = ∫ +𝜀𝑝 +𝑑𝜀𝑝 +𝜀𝑝 +and the resulting damage surface is given as +𝜎𝑑(𝑝∗, 𝐬, 𝜀̇𝑝) = +⎧ +{{{ +⎨ +{{{ +⎩ +𝜎𝑦(𝑝∗, 𝐬, 𝜀̇𝑝, 1)(1 − 𝐷) + 𝐷𝑓𝑐𝜎𝑟 +∗(𝑝∗) +0 ≤ 𝑝∗ +𝜎𝑦(𝑝∗, 𝐬, 𝜀̇𝑝, 1) (1 − 𝐷 − +𝑝∗ +∗) +𝑝𝑡 +(1 − 𝐷)𝑝𝑡 +∗ ≤ 𝑝∗ < 0 +where +∗(𝑝∗) = 𝐴𝑓 {𝑝∗}𝑛𝑓 +𝜎𝑟 +Plastic flow occurs in the direction of deviatoric stress, i.e., +ε̇𝑝~𝐬 +but for tension there is an option to set the parameter PFC to a number corresponding +to the influence of plastic volumetric strain. If 𝜆 ≤ 1 is used to denote this parameter, +then for the special case of 𝜆 = 1 +ε̇𝑝~𝐬 − 𝑝𝐈 +This was introduced to reduce noise in tension that was observed on some test +problems. A failure strain can be used to erode elements with severe deformation +which by default is set to 200%. +For simplicity, automatic generation of material parameters +is available via +ONEMPA.LT.0, then no other parameters are needed. If FC.EQ.0 then the 35 MPa +strength concrete in Riedel (2004) is generated in the units specified by the value of +ONEMPA. For FC.GT.0 then FC specifies the actual strength of the concrete in the units +specified by the value of ONEMPA. The other parameters are generated by +interpolating between the 35 MPa and 140 MPa strength concretes as presented in +Riedel (2004). Any automatically generated parameter may be overridden by the user if +motivated, one of these parameters may be the initial porosity ALPHA0 of the concrete. +For post-processing, the following history variables may be of interest +History variable #2 Internal energy per volume (ρe) +History variable #3 Porosity value (α) +History variable #4 Damage value (D) +or as an alternative use a material history list +*DEFINE_MATERIAL_HISTORIES Properties +Label +Attributes +Description +Damage +- +- +- +- Damage value 𝐷 +*MAT_CONCRETE_DAMAGE_PLASTIC_MODEL +*MAT_CDPM +This is material type 273. CDPM is a damage plastic concrete model based on work +published in Grassl et al. (2011, 2013) and Grassl and Jirásek (2006). This model is +aimed to simulations where failure of concrete structures subjected to dynamic loadings +is sought. It describes the characterization of the failure process subjected to multi-axial +and rate-dependent loading. The model is based on effective stress plasticity and with a +damage model based on both plastic and elastic strain measures. This material model is +available only for solids. +There are a lot of parameters for the advanced user but note that most of them have +default values that are based on experimental tests. They might not be useful for all +types of concrete and all types of load paths but they are values that can be used as a +good starting point. If the default values are not good enough the theory chapter at the +end of the parameter description can be of use. +History variables of interest are: +1 – kappa, 𝜅, see equations below +15 – damage in tension, 𝜔𝑡, see equations below +16 – damage in compression, 𝜔𝑐, see equations below +More details on this material can be found on: +http://petergrassl.com/Research/DamagePlasticity/CDPMLSDYNA/index.html + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E +F +4 +PR +F +5 +6 +ECC +QH0 +F +F +7 +FT +F +8 +FC +F +Default +none +none +none +0.2 +AUTO +0.3 +none +none +Card 2 +Variable +1 +HP +Type +F +2 +AH +F +3 +BH +F +4 +CH +F +5 +DH +F +6 +AS +F +7 +DF +F +8 +FC0 +F +Default +0.5 +0.08 +0.003 +2.0 +1.0E-6 +15.0 +0.85 +AUTO + Card 3 +1 +Variable +TYPE +Type +F +2 +BS +F +3 +WF +4 +5 +6 +7 +8 +WF1 +FT1 +STRFLG +FAILFLG +EFC +F +F +F +F +F +F +Default +0.0 +1.0 +none 0.15*WF 0.3*FT +0.0 +0.0 +1.0E-4 + VARIABLE +DESCRIPTION +MID +RO +E +PR +ECC +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density. +Young’s modulus. The sign determines if an anisotropic (E +positive, referred to as ISOFLAG = 0 in the remarks) or an +isotropic (E negative, referred to as ISOFLAG = 1 in the remarks) +damage formulation is used. The Young’s modulus is taken as +the absolute value of this parameter. +Poissons ratio +Eccentricity parameter. +EQ.0.0: ECC is calculated from Jirásek and Bazant (2002) as +ECC = +1 + 𝜖 +2 − 𝜖 +, +𝜖 = +𝑓𝑡(𝑓𝑏𝑐 +𝑓𝑏𝑐(𝑓𝑐 +2 − 𝑓𝑐 +2 − 𝑓𝑡 +2) +2) +, +𝑓𝑏𝑐 = 1.16𝑓𝑐 +QH0 +Initial hardening defined as FC0/FC where FC0 is the compressive +stress at which the initial yield surface is reached. Default = 0.3 +FT +FC +HP +AH +BH +CH +DH +AS +DF +FC0 +Uniaxial tensile strength (stress) +Uniaxial compression strength (stress) +Hardening parameter. Default is HP = 0.5 which is the value +used in Grassl et al. (2011) for strain rate dependent material +response (STRFLG = 1). For applications without strain rate effect +(STRFLG = 0) a value of HP = 0.01 is recommended, which has +been used in Grassl et al. (2013). +Hardening ductility parameter 1 +Hardening ductility parameter 2 +Hardening ductility parameter 3 +Hardening ductility parameter 4 +Ductility parameter during damage +Flow rule parameter +Rate dependent parameter. +if STRFLG = 1. +Recommended value is 10 MPa, which has to be entered +consistently with the system of units used. + Only needed +TYPE +Flag for damage type. +EQ.0.0: Linear damage formulation +EQ.1.0: Bi-linear damage formulation +EQ.2.0: Exponential damage formulation +EQ.3.0: No damage +The best results are obtained with the bi-linear formulation. +Damage ductility exponent during damage. +Default = 1.0 +threshold value +formulation. +Tensile +Parameter controlling tensile softening branch for exponential +tensile damage formulation. +linear damage +for +Tensile threshold value for the second part of the bi-linear +damage formulation. +Default = 0.15 × WF +BS +WF +WF1 +FT1 +strength +Tensile +formulation. +Default = 0.3 × FT +STRFLG +Strain rate flag. +threshold value +for bi-linear damage +EQ.1.0: Strain rate dependent +EQ.0.0: No strain rate dependency. +FAILFLG +Failure flag. +EQ.0.0: Not active ⇒ No erosion. +GT.0.0: Active and element will erode if wt and wc is equal to +1 in FAIFLG percent of the integration points. If FAIL- +FLG = 0.60, 60% of all integration points must fail be- +fore erosion. +EFC +Parameter controlling compressive damage softening branch in +the exponential compressive damage formulation. +Default = 1.0E-4 +Remarks: +The stress for the anisotropic damage plasticity model (E positive, ISOFLAG = 0) is +defined as +𝝈 = (1 − 𝜔𝑡)𝝈𝑡 + (1 − 𝜔𝑐)𝝈𝑐 +where 𝝈𝑡 and 𝝈𝑐 are the positive and negative part of the effective stress 𝝈eff determined +in the principal stress space. The scalar functions 𝜔𝑡 and 𝜔𝑐 are damage parameters. +The stress for the isotropic damage plasticity model (E negative, ISOFLAG = 1) is +defined as +𝝈 = (1 − 𝜔𝑡)𝝈eff +The effective stress 𝝈𝐞𝐟𝐟 is defined according to the damage mechanics convention as +𝝈𝐞𝐟𝐟 = 𝑫𝒆: (𝜺 − 𝜺𝒑) +Plasticity: +The yield surface is described by the Haigh-Westergaard coordinates: the volumetric +effective stress 𝜎𝑣, the norm of the deviatoric effective stress 𝜌 and the Lode angle 𝜃, and +it is given by +𝑓𝑝(𝜎𝑣, 𝜌, 𝜃, 𝜅) = +[1 − 𝑞1(𝜅)] +⎡ +⎢⎢⎢ +⎣ +− 𝑞1 +2(𝜅)𝑞2 +2(𝜅) . +⎜⎜⎛ 𝜌 +√6𝑓𝑐 +⎝ ++ +𝜎𝑣 +⎟⎟⎞ +𝑓𝑐 ⎠ ++ √ +𝑓𝑐 +⎤ +⎥⎥⎥ +⎦ ++ 𝑚0𝑞1(𝜅)2𝑞2(𝜅) +⎡ 𝜌 +⎢ +√6𝑓𝑐 +⎣ +𝑟(cos 𝜃) + +𝜎𝑣 +⎤ +⎥ +𝑓𝑐 ⎦ +The variables 𝑞1 and 𝑞2 are dependent on the hardening variable 𝜅. The parameter 𝑓𝑐 is +the uniaxial compressive strength. The shape of the deviatoric section is controlled by +the function +𝑟(cos 𝜃) = +4(1 − 𝑒2) cos2 𝜃 + (2𝑒 − 1)2 +2(1 − 𝑒2) cos 𝜃 + (2𝑒 − 1)√4(1 − 𝑒2) cos2 𝜃 + 5𝑒2 − 4𝑒 +where 𝑒 is the eccentricity parameter (ECC). The parameter 𝑚0 is the friction parameter +and it is defined as +𝑚0 = +where 𝑓𝑡 is the tensile strength. +3(𝑓𝑐 +2 − 𝑓𝑡 +𝑓𝑐𝑓𝑡 +) +𝑒 + 1 +The flow rule is non-associative which means that the direction of the plastic flow is not +normal to the yield surface. This is important for concrete since an associative flow rule +would give an overestimated maximum stress. The plastic potential is given by +𝑔(𝜎𝑣, 𝜌, 𝜅) = +{⎧ +⎩{⎨ +[1 − 𝑞1(𝜅)] +⎜⎛ 𝜌 +√6𝑓𝑐 +⎝ ++ +𝜎𝑣 +⎟⎞ +𝑓𝑐 ⎠ ++ √ +}⎫ +𝑓𝑐⎭}⎬ ++ 𝑞1(𝜅) +⎜⎛𝑚0𝜌 +√6𝑓𝑐 +⎝ ++ +𝑚𝑔(𝜎𝑣, 𝜅) +𝑓𝑐 +⎟⎞ +⎠ +where +and +𝑚𝑔(𝜎𝑣, 𝜅) = 𝐴𝑔(𝜅)𝐵𝑔(𝜅)𝑓𝑐𝑒 +𝜎𝑣−𝑞2𝑓𝑡/3 +𝐵𝑔𝑓𝑐 +𝐴𝑔 = +3𝑓𝑡𝑞2(𝜅) +𝑓𝑐 ++ +𝑚0 +, +𝐵𝑔 = +𝑞2(𝜅) +1 + 𝑓𝑡/𝑓𝑐 +ln +𝐴𝑔 +3𝑞2 + +𝑚0 + + ln ( +𝐷𝑓 + 1 +2𝐷𝑓 − 1 +) +The hardening laws 𝑞1 and 𝑞2 control the shape of the yield surface and the plastic +potential, and they are defined as +𝑞1(𝜅) = 𝑞ℎ0 + (1 − 𝑞ℎ0)(𝜅3 − 3𝜅2 + 3𝜅) − 𝐻𝑝(𝜅3 − 3𝜅2 + 2𝜅), +𝜅 < 1 +𝑞1(𝜅) = 1, 𝜅 ≥ 1 +𝑞2(𝜅) = 1, 𝜅 < 1 +𝑞2(𝜅) = 1 + 𝐻𝑝(𝜅 − 1), 𝜅 ≥ 1 +The evolution for the hardening variable is given by +4𝜆̇ cos2 𝜃 +𝑥ℎ(𝜎𝑣) +It sets the rate of the hardening variable to the norm of the plastic strain rate scaled by a +ductility measure which is defined below as +𝑑𝑔 +𝑑𝜎 +𝜅̇ = +∥ +∥ +− +𝑥ℎ(𝜎𝑣) = 𝐴ℎ − (𝐴ℎ − 𝐵ℎ)𝑒 +𝑅ℎ +𝐹ℎ + 𝐷ℎ, 𝑅ℎ < 0 +𝑅ℎ +𝐶ℎ, 𝑅ℎ ≥ 0 +𝑥ℎ(𝜎𝑣) = 𝐸ℎ𝑒 +And finally +Damage: +𝐸ℎ = 𝐵ℎ − 𝐷ℎ, +𝐹ℎ = +(𝐵ℎ − 𝐷ℎ)𝐶ℎ +𝐴ℎ − 𝐵ℎ +Damage is initialized when the equivalent strain 𝜀̃ reaches the threshold value 𝜀0 = 𝑓𝑡 𝐸⁄ +where the equivalent strain is defined as +𝜀̃ = +𝜀0𝑚0 +⎡ 𝜌 +⎢ +2 ⎣ +√6𝑓𝑐 +𝑟(𝑐𝑜𝑠𝜃) + +𝜎𝑉 +⎤ + +⎥ +𝑓𝑐 ⎦ +2𝑚0 +𝜀0 +4 ⎝ +⎜⎛ 𝜌 +√6𝑓𝑐 +𝑟(𝑐𝑜𝑠𝜃) + +𝜎𝑉 +⎟⎞ +𝑓𝑐 ⎠ ++ +2𝜌2 +3𝜀0 +2 +2𝑓𝑐 +√ +√√ +⎷ +Tensile damage is described by a stress-inelastic displacement law. For linear and +exponential damage type the stress value 𝑓𝑡 and the displacement value 𝑤𝑓 must be +defined. For the bi-linear type two additional parameters 𝑓𝑡1 and 𝑤𝑓1 must be defined, +see figure below how the stress softening is controlled by the input parameters. +𝜎𝑡 +𝑓𝑡 +𝜎𝑡 +𝑓𝑡 +𝑓𝑡1 +𝜎𝑡 +𝑓𝑡 +𝑤𝑓 +𝜀𝑡ℎ +𝑤𝑓1 +𝑤𝑓 +𝜀𝑡ℎ +𝑤𝑓 +𝜀𝑡ℎ +The variable ℎ is a mesh-dependent measure used to convert strains to displacements. +The variable 𝜀𝑡 is called the inelastic tensile strain and is defined as the sum of the +irreversible plastic strain 𝜀𝑝 and the reversible strain 𝑤𝑡(𝜀 − 𝜀𝑝) (in compression +𝑤𝑐(𝜀 − 𝜀𝑝)). To get the influence of multi-axial stress states on the softening a damage +ductility measure 𝑥𝑠 is added: +Where 𝐴𝑠 and 𝐵𝑠 are input parameters, and +𝑥𝑠 = 1 + (𝐴𝑠 − 1)𝑅𝑠 +𝐵𝑠 +𝑅𝑠 = − +√6𝜎𝑣 +, +𝜎𝑣 < 0 𝑎𝑛𝑑 𝑅𝑠 = 0, +𝜎𝑣 > 0 +The inelastic strain is then modified according: +𝜀𝑖 +𝑥𝑠 +𝜀𝑖 = +Compressive damage is controlled by an exponential stress-inelastic strain law. Stress +value 𝒇𝒄 and inelastic strain 𝜺𝒇𝒄 need to be specified, see figure below how the stress +softening is controlled by the input parameters. A small value of 𝜺𝒇𝒄, i.e. 1.0E-4 +(default), provides for a rather brittle form of damage. +𝜎𝑐 +𝑓𝑐 +𝐴𝑠 𝜀𝑓𝑐 +𝜀𝑐 +Strain rate: +Concrete is strongly rate dependent. If the loading rate is increased, the tensile and +compressive strength increase and are more prominent in tension then in compression. +The dependency is taken into account by an additional variable 𝛼𝑟 ≥ 1. The rate +dependency is included by scaling both the equivalent strain rate and the inelastic +strain. The rate parameter is defined by +𝛼𝑟 = (1 − 𝑋compression) 𝛼𝑟𝑡 + 𝑋compression𝛼𝑟𝑐 +Where 𝑋compression is continuous compression measure (= 1 means only compression, = 0 +means only tension) and for tension we have +𝛼𝑟𝑡 = +𝛿𝑡 +⎧ +) +( +{{{{{ +{{{{{ +𝛽𝑡 ( +⎩ +𝜀̇max +𝜀̇𝑡0 +𝜀̇max +𝜀̇𝑡0 +⎨ +𝜀̇max < 30 × 10−6𝑠−1 +30 × 10−6 < 𝜀̇max < 1 𝑠−1 +) + 𝜀̇max > 1 𝑠−1 +where 𝛿𝑡 = 1 +rate factor is given by +1+8𝑓𝑐/𝑓𝑐0 + , 𝛽𝑡 = 𝑒6𝛿𝑡−2 and 𝜀̇𝑡0 = 1 × 10−6𝑠−1. For compression the corresponding +𝛼𝑟𝑐 = +⎧1 +[𝑆 +{{{{{ +{{{{{ +𝛽𝑐 [ +⎩ +⎨ +] +|𝜀̇min| +𝜀̇𝑐0 +|𝜀̇min| +𝜀̇𝑐0 +1.026𝛿𝑐 +|𝜀̇min| < 30 × 10−6𝑠−1 +30 × 10−6 < |𝜀̇min| < 1𝑠−1 +] +| 𝜀̇min| > 30𝑠−1 +where 𝛿𝑐 = 1 +parameter. A recommended value is 10MPa. +5+9𝑓𝑐/𝑓𝑐0 +, 𝛽𝑐 = 𝑒6.156𝛿𝑐−2 and 𝜀̇𝑐0 = 30 × 10−6𝑠−1. The parameter 𝑓𝑐0 is an input +*MAT_PAPER +This is material type 274. This is an orthotropic elastoplastic model for paper materials, +based on Xia (2002) and Nygards (2009), and is available for solid and shell elements. +Solid elements use a hyperelastic-plastic formulation, while shell elements use a +hypoelastic-plastic formulation. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +E1 +F +4 +E2 +F +5 +E3 +F +6 +7 +8 +PR21 +PR32 +PR31 +F +F +F +Default +none +none +none +none +none +none +none +none + Card 2 +1 +2 +3 +4 +Variable +G12 +G23 +G13 +E3C +Type +F +F +F +F +5 +CC +F +TWOK +F +6 +7 +8 +Default +none +none +none +none +none +none +ROT +F +0.0 +In plane Yield Surface Card 1. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +S01 +A01 +B01 +C01 +S02 +A02 +B02 +C02 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +*MAT_274 + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +S03 +A03 +B03 +C03 +S04 +A04 +B04 +C04 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +In plane Yield Surface Card 3. + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +S05 +A05 +B05 +C05 +PRP1 +PRP2 +PRP4 +PRP5 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +1/2 +2/15 +1/2 +2/15 +Out of Plane and Transverse Shear Yield Surface Card. + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ASIG +BSIG +CSIG +TAU0 +ATAU +BTAU +Type +F +F +F +F +F +F +Default +none +none +none +none +none +none +Card 7 +1 +2 +Variable +AOPT +MACF +Type +F +F +*MAT_PAPER +3 +XP +F +4 +YP +F +5 +ZP +F +6 +A1 +F +7 +A2 +F +8 +A3 +F +Default +none +none +none +none +none +none +none +none +Orthotropic Parameter Card 2. + Card 8 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +7 +8 +BETA +F +Default +none +none +none +none +none +none +none + VARIABLE +DESCRIPTION +MID +RO +Ei +PRij +Gij +E3C +CC +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Material density +Young’s modulus in direction 𝐸𝑖. +Elastic Poisson’s ratio 𝜈𝑖𝑗. +Elastic shear modulus in direction 𝐺𝑖𝑗. +Elastic compression parameter. +Elastic compression exponent. +TWOK +Exponent in in-plane yield surface. +ROT +Option for 2D-solids (shell element form 13,14,15): +EQ.0.0: No rotation of material axes (default). Direction of +material axes are solely defined by AOPT and it is only +possible to rotate in shell-plane. +EQ.1.0: Rotate coordinate system around material 1-axis such +that 2-axis coincides with shell normal. This rotation is +done in addition to AOPT. +EQ.2.0: Rotate coordinate system around material 2-axis such +that 1-axis coincides with shell normal. This rotation is +done in addition to AOPT. +𝑖th in-plane plasticity yield parameter. If S0i < 0 the absolute +value of S0i is a curve number, see remarks. +𝑖th in-plane plasticity hardening parameter. +𝑖th in-plane plasticity hardening parameter. +𝑖th in-plane plasticity hardening parameter. +Tensile plastic Poisson’s ratio in direction 1. +Tensile plastic Poisson’s ratio in direction 2. +Compressive plastic Poisson’s ratio in direction 1. +Compressive plastic Poisson’s ratio in direction 2. +Out-of-plane plasticity yield parameter. +Out-of-plane plasticity hardening parameter. +Out-of-plane plasticity hardening parameter. +Transverse shear plasticity yield parameter. +Transverse shear plasticity hardening parameter. +Transverse shear plasticity hardening parameter. +S0i +A0i +B0i +C0i +PRP1 +PRP2 +PRP4 +PRP5 +ASIG +BSIG +CSIG +TAU0 +ATAU +BTAU +AOPT +Material axes option : +EQ.0.0: locally orthotropic with material axes determined by +element nodes 1, 2, and 4, as with *DEFINE_COORDI- +NATE_NODES. +EQ.1.0: locally orthotropic with material axes determined by a +point in space and the global location of the element +center; this is the a-direction. This option is for solid +elements only. +EQ.2.0: globally orthotropic with material axes determined by +vectors defined below, as with *DEFINE_COORDI- +NATE_VECTOR. +EQ.3.0: locally orthotropic material axes determined by +rotating the material axes about the element normal by +an angle, BETA, from a line in the plane of the element +defined by the cross product of the vector v with the +element normal. +EQ.4.0: locally orthotropic in cylindrical coordinate system +with the material axes determined by a vector v, and +an originating point, p, which define the centerline ax- +is. This option is for solid elements only. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +MACF +Material axes change flag for brick elements: +EQ.1: No change, default, +EQ.2: switch material axes a and b, +EQ.3: switch material axes a and c, +EQ.4: switch material axes b and c. +XP, YP, ZP +Define coordinates of point 𝐩 for AOPT = 1 and 4. +A1, A2, A3 +Define components of vector 𝐚 for AOPT = 2. +V1, V2, V3 +Define components of vector 𝐯 for AOPT = 3 and 4. +D1, D2, D3 +Define components of vector 𝐝 for AOPT = 2. +the element card, see *ELEMENT_SHELL_BETA or *ELEMENT_- +SOLID_ORTHO. +*MAT_PAPER +BETA +Remarks: +The stress-strain relationship for solid elements is based on a multiplicative split of the +deformation gradient into an elastic and a plastic part +The elastic Green strain is formed as +𝐅 = 𝐅𝑒𝐅𝑝. +𝐄𝑒 = +(𝐅𝑒 +T𝐅𝑒 − 𝐈), +and the 2nd Piola-Kirchhoff stress as +𝐒 = 𝐂𝐄𝑒, +where the constitutive matrix is taken as orthotropic and can be represented in Voigt +notation by its inverse as +𝐂−1 = +𝐸1 +𝜐12 +𝐸1 +𝜐13 +𝐸1 +− +− +𝜐21 +𝐸2 +𝐸2 +𝜐23 +𝐸2 +− +− +𝜐31 +𝐸3 +𝜐32 +𝐸3 +𝐸3 +⎤ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +. +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +⎥ +𝐺13⎦ +𝐺12 +𝐺23 +− +− +⎡ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎢ +⎣ +In out-of-plane compression the stress is modified according to +𝑆33 = 𝐶31𝐸11 +𝑒 + 𝐶32𝐸22 +𝑒 + { +𝑐 [1 − exp(−𝐶𝑐𝐸33 +𝐸3 +𝑒 , +𝐸3𝐸33 +𝑒 )], +𝑒 ≥ 0, +𝑒 < 0. +𝐸33 +𝐸33 +Three yield surfaces are present: in-plane, out-of-plane, and transverse shear. The in- +plane yield surface is given as +𝑓 = ∑ +𝑖=1 +⎡max(0, 𝑆: 𝑁𝑖) +⎢ +𝑓 ) +𝑞𝑖(𝜀𝑝 +⎣ +2𝑘 +⎤ +⎥ +⎦ +− 1 ≤ 0 +, +with the 6 yield plane normals (in strain Voigt notation) +𝜐1𝑝 +− +√1 + 𝜐1𝑝 +√1 + 𝜐1𝑝 +𝑁1 = +⎡ +⎢ +⎣ +𝑁2 = +⎡− +⎢ +⎣ +𝜐2𝑝 +√1 + 𝜐2𝑝 +√1 + 𝜐2𝑝 +⎤ +⎥ +⎦ +⎤ +⎥ +⎦ +, +, +𝑁3 = [0 +0 √2 +𝑁4 = − +⎡ +⎢ +√1 + 𝜐4𝑝 +⎣ +− +0] +, +𝜐4𝑝 +√1 + 𝜐4𝑝 +𝑁5 = − +⎡− +⎢ +⎣ +𝜐5𝑝 +√1 + 𝜐5𝑝 +√1 + 𝜐5𝑝 +𝑁6 = −𝑁3. +The yield planes describe the following states +⎤ +⎥ +⎦ +⎤ +⎥ +⎦ +, +, +Each hardening function 𝑞𝑖 (note that 𝑞6 = 𝑞3) is given by a load curve if 𝑆𝑖 +otherwise +0 < 0, +𝑞𝑖(𝜀𝑝 +𝑓 ) = 𝑆𝑖 +0 + 𝐴𝑖 +0 tanh(𝐵𝑖 +0𝜀𝑝 +𝑓 ) + 𝐶𝑖 +𝑓 . +0𝜀𝑝 +The out-of-plane surface is given as +𝑔 = +−𝑆33 +𝑔) +𝐴𝜎 + 𝐵𝜎 exp(−𝐶𝜎𝜀𝑝 +− 1 ≤ 0, +and the transverse shear surface is +ℎ = +√𝑆13 +2 + 𝑆23 +𝜏0 + [𝐴𝜏 − min(0, 𝑆33) 𝐵𝜏]𝜀𝑝 +− 1 ≤ 0. +The flow rule is given by the evolution of the plastic deformation gradient +where the plastic velocity gradient is given as +𝐅̇𝑝 = 𝐋𝑝𝐅𝑝, +𝐋𝑝 = +𝑓 𝜕𝑓 +𝜕𝑆11 +⎡𝜀̇𝑝 +⎢ +⎢ +𝑓 𝜕𝑓 +⎢ +𝜀̇𝑝 +⎢ +𝜕𝑆12 +⎢ +⎢ +ℎ 𝜕ℎ +⎢ +𝜀̇𝑝 +𝜕𝑆13 +⎣ +𝑓 𝜕𝑓 +𝜀̇𝑝 +𝜕𝑆12 +𝑓 𝜕𝑓 +𝜀̇𝑝 +𝜕𝑆22 +ℎ 𝜕ℎ +𝜀̇𝑝 +𝜕𝑆23 +ℎ 𝜕ℎ +𝜀̇𝑝 +𝜕𝑆13 +ℎ 𝜕ℎ +𝜀̇𝑝 +𝜕𝑆23 +𝑔 𝜕𝑔 +𝜀̇𝑝 +⎤ +⎥ +⎥ +⎥ +, +⎥ +⎥ +⎥ +⎥ +𝜕𝑆33⎦ +and where it is implicitly assumed that the involved derivatives in the expression of the +velocity gradient is appropriately normalized. +The stress-strain relationship for shell elements is based on an additive split of the rate +of deformation into an elastic and a plastic part +𝐃 = 𝐃𝑒 + 𝐃𝑝, +and the rate of Cauchy stress is given by +𝛔̇ = 𝐂𝐃𝑒. +In out-of-plane compression the stress rate is modified according to +𝜎̇33 = 𝐶31𝐷11 +𝑒 + 𝐶32𝐷22 +𝑒 + 𝐷33 +𝑒 { +𝑐 exp(−𝐶𝑐𝜀33 +𝐸3 +𝐸3, +𝑒 ) , +𝑒 ≥ 0, +𝜀33 +𝑒 < 0. +𝜀33 +For shell elements, 𝐷33 +surface +𝑝 = 0, and only two yield surfaces are present: the in-plane yield +𝑓 = ∑ +𝑖=1 +⎡max(0, 𝜎: 𝑁𝑖) +⎢ +𝑓 ) +𝑞𝑖(𝜀𝑝 +⎣ +2𝑘 +⎤ +⎥ +⎦ +− 1 ≤ 0 +, +and the transverse-shear yield surface +ℎ = +√𝜎13 +2 + 𝜎23 +𝜏0 + [𝐴𝜏 − min(0, 𝜎33) 𝐵𝜏]𝜀𝑝 +− 1 ≤ 0, +and the plastic flow rule is given by +where the plastic velocity gradient is given as +𝛆̇𝑝 = 𝐃𝑝 = 𝐋𝑝, +𝐋𝑝 = +𝑓 𝜕𝑓 +𝜕𝜎11 +⎡𝜀̇𝑝 +⎢ +⎢ +𝑓 𝜕𝑓 +⎢ +𝜀̇𝑝 +⎢ +𝜕𝜎12 +⎢ +⎢ +ℎ 𝜕ℎ +⎢ +𝜀̇𝑝 +𝜕𝜎13 +⎣ +𝑓 𝜕𝑓 +𝜀̇𝑝 +𝜕𝜎12 +𝑓 𝜕𝑓 +𝜀̇𝑝 +𝜕𝜎22 +ℎ 𝜕ℎ +𝜀̇𝑝 +𝜕𝜎23 +ℎ 𝜕ℎ +𝜀̇𝑝 +𝜕𝜎13 +ℎ 𝜕ℎ +𝜀̇𝑝 +𝜕𝜎23 +⎤ +⎥ +⎥ +⎥ +. +⎥ +⎥ +⎥ +⎥ +⎦ +History variables: +History variables 1 to 3 show 𝜀𝑝 +𝑓 , 𝜀𝑝 +𝑔 and 𝜀𝑝 +ℎ, respectively. The Effective Plastic Strain is +𝑓 ) +𝜀𝑝 = √(𝜀𝑝 +𝑔) ++ (𝜀𝑝 +ℎ) ++ (𝜀𝑝 +*MAT_SMOOTH_VISCOELASTIC_VISCOPLASTIC +This is Material Type 275, a smooth viscoelastic viscoplastic model based on the works +of Hollenstein et.al. [2013, 2014] and Jabareen [2015]. The stress response is +rheologically represented by HJR (Hollenstein-Jabareen-Rubin) elements in parallel, see +Figure 0-1, where each element exhibits combinations of viscoelastic and viscoplastic +characteristics. The model is based on large displacement hyper-elastoplasticity and the +numerical implementation is strongly objective, this together with the smooth +characteristics makes it especially suitable for implicit analysis. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F +3 +K +F +4 +5 +6 +7 +8 +HJR Element Cards. At least 1 and optionally up to 6 cards should be input. A +keyword card (with a “*” in column 1) terminates this input, if less than 6 cards are +used. + Card 2 +Variable +1 +A0 +Type +F +2 +B0 +F +3 +A1 +F +4 +B1 +F +5 +M +F +6 +7 +8 +KAPAS +KAPA0 +SHEAR +F +F +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +K +A0 +B0 +A1 +B1 +Mass density. +Elastic bulk modulus. +Rate dependent understress viscoplastic parameter. +Rate independent understress plasticity parameter. +Rate dependent overstress viscoplastic parameter. +Rate independent overstress plasticity parameter. +𝐹 +𝐺 +𝑎0 +𝑏0 +𝑏1 +𝑎1 +𝜅(𝜅0, 𝜅𝑠, 𝑚) +Figure 0-1. Rheological representation of an HJR element, including the associated +parameters. + VARIABLE +DESCRIPTION +Exponential hardening parameter. +Saturated yield strain. +Initial yield strain. +Elastic shear modulus. +M +KAPAS +KAPA0 +SHEAR +Remarks: +The Cauchy stress for this smooth viscoelastic viscoplastic material is given by +𝛔 = 𝐾(𝐽 − 1)𝐈 + ∑ 𝐬𝑖 +, +𝑖=1 +where 𝐾 is the elastic bulk modulus provided on the first card, 𝐽 = det(𝐅) is the relative +volume with 𝑭 being the total deformation gradient, and the deviatoric stresses 𝒔𝑖 are +coming from the HJR (Hollenstein-Jabareen-Rubin) elements in parallel. Up to 6 such +elements can be defined for the deviatoric response and a rheological representation of +one is shown in Figure 0-1. Each element is associated with 8 material parameters that +are provided on the optional cards and characterize its inelastic response. All this +allows for a wide range of stress strain relationships and the critical part would be to +estimate parameters for a given test suite, whence some elaboration on the physical +interpretation of the individual parameters in the context of uniaxial stress is given +following a general description of the model. +We analyze one HJR element by letting 𝐁̅̅̅̅ denote the associated isochoric elastic left +Cauchy-Green tensor. Define +The evolution of 𝐁̅̅̅̅ is given by +𝐁̃ = 𝐁̅̅̅̅ − 1 +3 𝛼𝐈, where 𝛼 = tr(𝐁̅̅̅̅ ). +a0 = 0.0 +a0 = 0.5 +a0 = 1.0 +a0 = 2.0 +1.2 +1.0 +0.8 +0.6 +0.4 +0.2 +0.0 +0.0 +1.0 +2.0 +3.0 +4.0 +5.0 +6.0 +7.0 +8.0 +9.0 +10.0 +Time +Figure M275-1. Influence of parameter 𝑎0 on stress relaxation +𝐁̅̅̅̅̇ = 𝐋𝐁̅̅̅̅ + 𝐁̅̅̅̅ 𝐋T − +tr(𝐃)𝐁̅̅̅̅ − 𝛤̇𝐀, where 𝐀 = 𝐁̅̅̅̅ − [ +tr(𝐁̅̅̅̅ −1) +] 𝐈 +where 𝐃 is the rate-of-deformation and 𝛤̇ governs the inelastic deformation. The +functional form of 𝛤̇ is summarized in the following set of equations +where +𝛤̇ = 𝛤̇0 + ⟨𝑔⟩𝛤̇1 +𝛤̇𝑖 = 𝑎𝑖 + 𝑏𝑖𝜀̇, +𝑔 = 1 − +𝛾̃ +𝑖 = 0,1 +⟨𝑔⟩ = max(0, 𝑔) , +𝜀̇ = √ +𝐃̃ +∶ 𝐃̃ , +𝐃̃ = 𝐃 − +tr(𝐃)𝐈, +𝛾̃ = √ +𝐁̃ ∶ 𝐁̃ , +𝜅̇ = 𝑚𝛤̇1⟨𝑔⟩(𝜅𝑠 − 𝜅). +A hyperelastic law with a strain energy potential for the distortional deformation given +by +b0 = 0 +b0 = 5 +b0 = 25 +b0 = 50 +0.300 +0.200 +0.100 +0.000 +-0.100 +-0.200 +-0.300 +-15.0 +-10.0 +-5.0 +0.0 +5.0 +10.0 +15.0 +Strain % +Figure M275-2. Influence of 𝑏0 in cyclic loading +𝜓(𝛼) = +(𝛼 − 3) +yields a contribution to the deviatoric Cauchy stress of +𝐬 = 𝐺𝐽−1𝐁̃ . +In uniaxial stress at constant total distortional rate of deformation ±𝜀̇ (tension or +compression), these equations can be reduced to scalar correspondents +𝑏̅ +𝑏̅ += 2 +⎜⎜⎛±𝜀̇ − 𝛤̇ +⎝ +𝑏̅√𝑏̅ − 1 +⎟⎟⎞ +2𝑏̅√𝑏̅ + 1⎠ +𝜏 = 𝐺 +⎜⎛𝑏̅ − +⎝ +⎟⎞ +√𝑏̅⎠ +(M275.1) +where 𝑏̅ is the component of 𝑩̅̅̅̅̅ in the direction of deformation and 𝜏 is the uniaxial +Kirchhoff stress. The evolution of 𝛤 follows the equations above with +𝛾̃ = 1 +2 ∣𝑏̅ − 1/√𝑏̅∣. +Even though analytical solutions may be out of reach, this would be the basis for +estimating as well as interpreting the material parameters. Obviously the shear +modulus 𝐺 (SHEAR) provides the elastic deviatoric stiffness, for a purely elastic +material just define one such parameter and leave out all the other parameters on the +same card. If several cards are used, the effective elastic shear stiffness is the sum of the +2-1404 (MAT_248) +0.07 +0.05 +0.02 +0.00 +-0.03 +-0.05 +-0.08 +b1 = 100 +b1 = 200 +b1 = 500 +b1 = 1000 +0.0 +0.5 +1.0 +1.5 +2.0 +2.5 +3.0 +3.5 +4.0 +4.5 +5.0 +Strain % +Figure M275-3. Effect of 𝑏1 in cyclic loading +contributions from each of the corresponding HJR elements. An interesting observation +is that the stress in a HJR element saturates to a value given by the solution of 𝑏̅ to +𝑏̅√𝑏̅ (±2 − {𝑏0 + 𝑏1 + +𝑎0 + 𝑎1 +𝜀̇ +}) ± 2√𝑏̅𝜅𝑠 (𝑏1 + +) +𝑎1 +𝜀̇ +𝑎0 + 𝑎1 +𝜀̇ ++ (±1 + {𝑏0 + 𝑏1 + +}) = 0 +(M275.2) +in tension (+) and compression (−), followed by application of (M275.1) above, this +assuming that +in tension +𝑏0 + 𝑏1 + +𝑎0 + 𝑎1 +𝜀̇ +> 2 +𝑏0 + 𝑏1 + +𝑎0 + 𝑎1 +𝜀̇ +> 1 +in compression. This expression will be utilized in special cases below when examining +each inelastic material parameter individually, the material parameters above are input +on the HJR element cards as A0, B0, A1, B1 and KAPAS. +A Maxwell material is obtained by providing an element with a nonzero 𝑎0 (A0) and +other parameters zero, this parameter should be interpreted as the viscoelastic +relaxation coefficient determining the rate at which the stress relaxes to zero, see +parameter BETA in *MAT_VISCOELASTIC. In Figure M275-1 a stress relaxation is +shown for a strain controlled problem using two HJR elements and normalized material +parameters using a bulk modulus of 𝐾 = 1. For the first element 𝐺 = 0.5 and for the +other 𝐺 = 1 and 𝑎0 varies, all other parameters are zero. The engineering strain is +ramped to 50% from 𝑡 = 0 to 𝑡 = 1 and then kept constant, the response is very similar +to other viscoelastic models in LS-DYNA. Not surprisingly, a HJR element with 𝑎0 > 0 +(and 𝑎1 = 𝑏1 = 0) will always relax to zero stress, which follows from (M275.1) and +(M275.2), thus the relaxed stress in this case comes from the purely elastic element. A +general viscoelastic material can be obtained by putting several such HJR elements in +parallel, in analogy to *MAT_GENERAL_VISCOELASTIC. +For a nonzero 𝑏0 (B0) and other parameters zero, a rate independent plastic response is +obtained exhibiting zero yield stress, i.e., inelastic strains develop immediately upon +loading. From (M275.2) the value of 𝑏0 determines the saturated stress value for the +associated HJR element by (M275.1) and +𝑏̅ = ( +𝑏0 ± 1 +𝑏0 ∓ 2 +2/3 +) +in tension (+) and compression (−), respectively. A smooth response is obtained that is +characterized by hysteresis as shown in Figure M275-2. The same material parameters +as in the previous example is used with the exception of varying 𝑏0 with vanishing 𝑎0. +The deformation is controlled by a cyclic Cauchy stress between −0.25 and 0.25, for +larger 𝑏0 a hysteresis is observed. It should however be mentioned that the hysteresis +vanishes as 𝑏0 → ∞ as the stress for the second element saturates quickly to a small +value, so it is not trivial to quantitatively estimate the amount of hysteresis for a given +parameter setting and deformation. +0.07 +0.05 +0.02 +0.00 +-0.03 +-0.05 +-0.08 +m = 0.1 +m = 0.2 +m = 0.5 +m = 1.0 +0.0 +0.5 +1.0 +1.5 +2.0 +2.5 +3.0 +3.5 +4.0 +4.5 +5.0 +Strain % +Figure M275-4. Softening response in cyclic loading for various values +of 𝑚 +Rate independent plasticity with a nonzero yield stress can be obtained by a nonzero 𝑏1 +(B1) in combination with parameters 𝜅0 (KAPA0), 𝜅𝑠 (KAPAS) and 𝑚 (M). The yield +stress in the sense of von Mises is given by +𝜎𝑌 = 2𝐺𝐽−1𝜅 +and whence 𝜅 is interpreted as the current yield strain. Here 𝑏1 determines the amount +of overstress through (M275.1) and (M275.2), requiring the solution of a non-trivial +polynomial equation. This is exemplified in Figure M275-3 using one HJR element with +𝐾 = 1, 𝐺 = 1.5, 𝜅0 = 𝜅𝑠 = 0.01 and 𝑚 = 0. The engineering strain is ramped up to 5% +and down to 0 and 𝑏1 is varied with all other parameters zero, the response tends to an +elastic-perfectly plastic as 𝑏1 increases. The saturated stress value for 𝑏1 → ∞ can be +calculated as +𝑏̅ = +⎡ +⎜⎜⎛1 +⎢⎢ +⎝ +⎣ ++ √ +∓ +8𝜅𝑠 +27 +⎟⎟⎞ +⎠ +1/3 ++ +⎜⎜⎛1 +⎝ +− √ +∓ +8𝜅𝑠 +27 +⎟⎟⎞ +⎠ +1/3 +⎤ +⎥⎥ +⎦ +(M275.3) +and employing (M275.1). +Isostropic strain hardening 𝜅𝑠 > 𝜅0 or softening 𝜅𝑠 < 𝜅0 is obtained with 𝑚 > 0, 𝜅 tends +exponentially towards 𝜅𝑠 at a rate determined by 𝑚. Using 𝑏1 = 1000, i.e., very little +overstress, 𝜅0 = 0.02, 𝜅𝑠 = 0.01 and varying 𝑚 the softening response in Figure M275-4 +is obtained. The rate at which the element hardens is difficult to quantitatively +estimate, but presumably it depends not only on 𝑚 but also on 𝑏1. It is important to +note however that for small to moderate 𝑏1 the model appears to harden with 𝑚 = 0, +de/dt = 0.2 +de/dt = 4.0 +de/dt = 10.0 +de/dt = 20.0 +0.125 +0.100 +0.075 +0.050 +0.025 +0.000 +-0.025 +-0.050 +-0.075 +0.0 +0.5 +1.0 +1.5 +2.0 +2.5 +3.0 +3.5 +4.0 +4.5 +5.0 +Strain % +Figure M275-5. Strain rate dependence for 𝑎1 = 1000 and 𝑏1 = 10 +which is due to larger overstress. The hardening determined by 𝑚 can be determined +from a loading, unloading and reloading cycle to detect how the the yield strain 𝜅 +changes, see Hollenstein et.al. [2013]. +Finally, 𝑎1 (A1) is the viscoplastic parameter determining how stress responds to change +in strain rate. Its interpretation is very similar to that of 𝑎0, stress increases with +increasing loading rate and relaxes to the saturated stress value given by (M275.1) and +(M275.2). In Figure M275-5 a rate dependency is illustrated for 𝐾 = 1, 𝐺 = 1.5, +𝜅0 = 𝜅𝑠 = 0.01 and 𝑚 = 0, where we have put 𝑎1 = 1000 and 𝑏1 = 10. The engineering +strain rate varies from 0.2 to 20 and for small strain rates (M275.3) can be used for +estimating the saturated stress, but in general (M275.2) must be used. +Putting several HJR elements in parallel can thus provide a fairly general combination +of viscoelastic/viscoplastic response with isotropic hardening/softening, but this of +course requires a rich test suite and a good way of estimating the material parameters. +Presumably it is often sufficient to neglect some effects and work with only a subset of +the material parameters. +For post-processing, the effective plastic strain in this model is defined as +where +𝜀𝑝 = √ +𝛆𝑝 ∶ 𝛆𝑝 +𝛆𝑝 = 𝛆𝑡 − 𝛆𝑒 +is a crude estimation of the difference between total and elastic strain. We set +where +𝛆𝑡 = +2𝐽 +[𝐁 − +tr(𝐁)𝐈] +𝛆𝑒 = +2𝐺 +[𝛔 − +tr(σ)𝐈] +𝐁 = 𝐽−2/3𝐅𝐅T +and 𝐺 here is the sum of all shear moduli defined on the HJR element cards. Note that +this does not correspond to the traditional measure of effective plastic strain which +should be accounted for when validating results. +*MAT_CHRONOLOGICAL_VISCOELASTIC +This is Material Type 276. This material model provides a general viscoelastic Maxwell +model having up to 6 terms in the prony series expansion and is useful for modeling +dense continuum rubbers and solid explosives. It is similar to Material Type 76 but +allows the incorporation of aging effects on the material properties. Either the +coefficients of the prony series expansion or a relaxation curve may be specified to +define the viscoelastic deviatoric and bulk behavior. +The material model can also be used with laminated shell. Either an elastic or +viscoelastic layer can be defined with the laminated formulation. To activate laminated +shell you need the laminated formulation flag on *CONTROL_SHELL. With the +laminated option a user defined integration rule is needed. + Card 1 +1 +Variable +MID +2 +RO +3 +4 +BULK +PCF +Type +A8 +F +F +F +5 +EF +F +6 +TREF +F +7 +A +F +8 +B +F +If fitting is done from a relaxation curve, specify fitting parameters on card 2, otherwise +if constants are set on Viscoelastic Constant Cards LEAVE THIS CARD BLANK. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCID +NT +BSTART +TRAMP +LCIDK +NTK +BSTARTK TRAMPK +Type +F +I +F +F +F +I +F +Viscoelastic Constant Cards. Up to 12 cards may be input. A keyword card (with a +“*” in column 1) terminates this input if less than 12 cards are used. These cards are not +needed if relaxation data is defined. The number of terms for the shear behavior may +differ from that for the bulk behavior: simply insert zero if a term is not included. If an +elastic layer is defined you only need to define GI and KI (note in an elastic layer only +one card is needed). + Optional +Variable +Type +1 +GI +F +2 +BETAI +F +3 +KI +F + VARIABLE +MID +4 +5 +6 +7 +8 +BETAKI +F +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density. +BULK +Elastic bulk modulus. +PCF +EF +TREF +A +B +LCID +NT +Tensile pressure elimination flag for solid elements only. If set to +unity tensile pressures are set to zero. +Elastic flag (if equal 1, the layer is elastic. If 0 the layer is +viscoelastic). +Reference temperature for shift function (must be greater than +zero). +Chronological coefficient 𝛼(𝑡𝑎). See Remarks below. +Chronological coefficient 𝛽(𝑡𝑎). See Remarks below. +Load curve ID for deviatoric behavior if constants, Gi, and βi are +determined via a least squares fit. This relaxation curve is shown +below. +Number of terms in shear fit. If zero the default is 6. Fewer than +NT terms will be used if the fit produces one or more negative +shear moduli. Currently, the maximum number is set to 6. +BSTART +*MAT_CHRONOLOGICAL_VISCOELASTIC +DESCRIPTION +In the fit, 𝛽1 is set to zero, 𝛽2 is set to BSTART, 𝛽3 is 10 times 𝛽2, +𝛽4 is 10 times 𝛽3 , and so on. If zero, BSTART is determined by an +iterative trial and error scheme. +TRAMP +Optional ramp time for loading. +LCIDK +Load curve ID for bulk behavior if constants, 𝐾𝑖, and 𝛽𝐾𝑖 are +determined via a least squares fit. This relaxation curve is shown +below. +NTK +Number of terms desired in bulk fit. If zero the default is 6. +Currently, the maximum number is set to 6. +BSTARTK +In the fit, Β𝐾1 is set to zero, Β𝐾2 is set to BSTARTK, 𝛽𝐾3 is 10 +times 𝛽𝐾2, is 𝛽𝐾4 10 times 𝛽𝐾3 , and so on. If zero, BSTARTK is +determined by an iterative trial and error scheme. +TRAMPK +Optional ramp time for bulk loading. +Gi +Optional shear relaxation modulus for the ith term +BETAi +Optional shear decay constant for the ith term +Ki +Optional bulk relaxation modulus for the ith term +BETAKi +Optional bulk decay constant for the ith term +Remarks: +The Cauchy stress, 𝜎𝑖𝑗, is related to the strain rate by +𝜎𝑖𝑗(𝑡) = −𝑝𝛿𝑖𝑗 + ∫ 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) +∂𝜀𝑘𝑙(𝜏) +∂𝜏 +𝑑𝜏 +For this model, it is postulated that the mathematical form is preserved in the +′ (𝑡𝑎, 𝑡) +constitutive equation for aging; however two new material functions, 𝑔0 +are introduced to replace 𝑔0 and 𝑔1(𝑡), which is expressed in terms of a Prony series as +in material model 76, *MAT_GENERAL_VISCOELASTIC. The aging time is denoted +by 𝑡𝑎. +′ (𝑡𝑎) and 𝑔1 +𝜎𝑖𝑗(𝑡𝑎, 𝑡) = −𝑝𝛿𝑖𝑗 + ∫ 𝑔𝑖𝑗𝑘𝑙 +′ (𝑡𝑎, 𝑡 − 𝜏) +∂𝜀𝑘𝑙(𝜏) +∂𝜏 +𝑑𝜏 +where +′ (𝑡𝑎, 𝑡) = 𝛼(𝑡𝑎)𝑔𝑖𝑗𝑘𝑙[𝛽(𝑡𝑎)𝑡] +𝑔𝑖𝑗𝑘𝑙 +where 𝛼(𝑡𝑎) and 𝛽(𝑡𝑎) are two new material properties that are functions of the aging +time 𝑡𝑎. The material properties functions 𝛼(𝑡𝑎) and 𝛽(𝑡𝑎) will be determined with the +experimental results. For determination of 𝛼(𝑡𝑎) and 𝛽(𝑡𝑎), Eq. (2) can be written in the +following form +log(𝜎𝑖𝑗 − 𝑝𝛿𝑖𝑗) += log𝛼(𝑡𝑎) + log(𝜎𝑖𝑗 − 𝑝𝛿𝑖𝑗) +𝑡𝑎=0,𝑡→𝜉 +𝑡𝑎,𝑡 +log𝜉 = log𝛽(𝑡𝑎) + log𝑡 +Therefore, if one plots the stress versus time on log-log scales, with the vertical axis +being the stress and the horizontal axis being the time, then the stress-relaxation curve +for any aged time history can be obtained directly from the stress-relaxation curve at +𝑡𝑎 = 0 by imposing a vertical shift and a horizontal shift on the stress-relaxation curves. +The vertical shift and the horizontal shift are log𝛼(𝑡𝑎) and log𝛽(𝑡𝑎) respectively. +*MAT_ADHESIVE_CURING_VISCOELASTIC +This is Material Type 277. It is useful for modeling adhesive materials during chemical +curing. This material model provides a general viscoelastic Maxwell model having up +to 16 terms in the Prony series expansion. It is similar to Material Type 76, but the +viscoelastic properties do not only depend on the temperature but also on an internal +variable representing the state of cure for the adhesive. The kinematic of the curing +process depends on temperature as well as on temperature rate and follows the Kamal +model. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +K1 +F +3 +4 +K2 +F +4 +5 +C1 +F +5 +Variable +CHEXP1 +CHEXP2 +CHEXP3 LCCHEXP LCTHEXP +Type +F + Card 3 +1 +F +2 +F +3 +I +4 +I +5 +6 +C2 +F +6 +R +F +6 +7 +M +F +7 +8 +N +F +8 +TREFEXP +DOCREFE +XP +F +7 +F +8 +Variable WLFTREF WLFA +WLFB +LCG0 +LCK0 +IDOC +INCR +Type +F +F +F +I +I +F +I +Viscoelastic Constant Cards. Up to 16 cards may be input. A keyword card (with a +“*” in column 1) terminates this input if less than 16 cards are used. The number of +terms for the shear behavior may differ from that for the bulk behavior: simply insert +zero if a term is not included. + Optional +Variable +Type +1 +GI +F +2-1414 (MAT_248) +2 +BETAGI +F +3 +KI +F +4 +5 +6 +7 +8 +BETAKI +VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +K1 +K2 +C1 +C2 +M +N +Mass density. +Parameter 𝑘1 for Kamal model. +Parameter 𝑘2 for Kamal model. +Parameter 𝑐1 for Kamal model. +Parameter 𝑐2 for Kamal model. +Exponent 𝑚 for Kamal model +Exponent 𝑛 for Kamal model. +CHEXP1 +CHEXP2 +CHEXP3 +LCCHEXP +LCTHEXP +R +TREFEXP +DOCREFEXP +Quadratic parameter 𝛾2 for chemical shrinkage. +Linear parameter 𝛾1 for chemical shrinkage. +Constant parameter 𝛾0 for chemical shrinkage. +Load curve ID to define the coefficient for chemical shrinkage +𝛾(𝛼) as a function of the state of cure 𝛼. If set, parameters +CHEXP1, CHEXP2 and CHEXP3 are ignored. +Load curve ID or table ID defining the instantaneous coefficient +of thermal expansion 𝛽(𝛼, 𝑇) as a function of cure 𝛼 and +temperature 𝑇. If referring to a load curve, parameter 𝛽(𝑇) is a +function of temperature 𝑇. +Gas constant 𝑅 for Kamal model. +Reference temperature 𝑇0 for secant form of thermal expansion. +See Remarks below. +Reference degree of cure 𝛼0 for sequential form of chemical +expansion. See Remarks below. +WLFTREF +Reference temperature for WLF shift function. +WLFA +WLFB +Parameter 𝐴 for WLF shift function. +Parameter 𝐵 for WLF shift function. +*MAT_ADHESIVE_CURING_VISCOELASTIC +DESCRIPTION +LCG0 +LCK0 +IDOC +INCR +Load curve ID defining the instantaneous shear modulus 𝐺0 as a +function of state of cure. +Load curve ID defining the instantaneous bulk modulus 𝐾0 as a +function of state of cure. +Initial degree of cure. +Switch between incremental and total stress formulation. +EQ.0: total form: (DEFAULT) +EQ.1: incremental form: (recommended) +GI +Shear relaxation modulus for the ith term for fully cured material. +BETAGI +Shear decay constant for the ith term for fully cured material. +KI +Bulk relaxation modulus for the ith term for fully cured material. +BETAKI +Bulk decay constant for the ith term for fully cured material. +Remarks: +Within this material formulation an internal variable 𝛼 has been included to represent +the degree of cure for the adhesive. The evolution equation for this variable is given by +the Kamal model and reads +dα +dt += (𝑘1 exp ( +−𝑐1 +𝑅𝑇 +) + 𝑘2 exp ( +−𝑐2 +𝑅𝑇 +) 𝛼𝑚) (1 − 𝛼)𝑛 +The chemical reaction of the curing process results in a shrinkage of the material. The +coefficient of the chemical shrinkage 𝛾(𝛼) can either be given by a load curve or using +the quadratic expression +𝛾(𝛼) = 𝛾2𝛼2 + 𝛾1𝛼 + 𝛾0 +For non-negative values of the reference degree of cure 𝛼0, a secant form is used to +compute the chemical strains +Otherwise a differential form is used: +𝜀𝑐ℎ = 𝛾(𝛼)(𝛼 − 𝛼0) − 𝛾(𝛼𝐼)(𝛼𝐼 − 𝛼0) +𝑑𝜀𝑐ℎ = 𝛾(𝛼)𝑑𝛼 +Analogously, the thermal strains are either defined in a secant or differential form, +depending on the reference temperature 𝑇0. In both cases the coefficient of thermal +expansion can be given as 2d table depending on degree of cure and temperature. +Finally, the Cauchy stress, 𝜎𝑖𝑗, is related to the strain rate by +𝜎𝑖𝑗(𝑡) = ∫ 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) +∂𝜀𝑘𝑙(𝜏) +∂𝜏 +𝑑𝜏 +The relaxation functions 𝑔𝑖𝑗𝑘𝑙(𝑡 − 𝜏) are represented in this material formulation by up to +16 terms (not including the instantaneous modulus 𝐺0) of the Prony series: +g(𝑡, 𝛼) = 𝐺0(𝛼) − ∑ 𝐺𝑖(𝛼) ++ ∑ 𝐺𝑖(𝛼) +𝑒−𝛽𝑖𝑡 +For the sake of simplicity, a constant ratio 𝐺𝑖(𝛼) 𝐺0(𝛼) + for all degrees of cure is +assumed. Consequently, it suffices to define one term 𝐺0(𝛼) as a function of the degree +of cure and further coefficients for the fully cured state of the adhesive: +⁄ +g(𝑡, 𝛼) = 𝐺0(𝛼) +⎜⎜⎛1 − ∑ +⎝ +𝐺𝑖,𝛼=1.0 +𝐺0,𝛼=1.0 +(1 − 𝑒−𝛽𝑖𝑡) +⎟⎟⎞ +⎠ +A possible temperature effect on the stress relaxation is accounted for by the Williams- +Landau-Ferry (WLF) shift function. For details on this function, please see material +formulation 76, *MAT_GENERAL_VISCOELASTIC. +*MAT_CF_MICROMECHANICS +This is Material Type 278 developed for draping and curing analysis of prepreg carbon +fiber sheets. This material model is mixture of MAT_234 and MAT_277, with MAT_234 +providing reorientation and locking phenomenon of fibers and MAT_277 providing the +viscoelastic behavior of epoxy resin. The overall stress has contribution from both fiber +orientation and deformation and epoxy resin. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +E1 +F +3 +4 +E2 +F +4 +5 +6 +G12 +G23 +F +5 +Variable +EKA +EUA +VMB +EKB +THL +Type +F + Card 3 +Variable +Type +1 +W +F +F +2 +F +3 +SPAN +THICK +F +F + Card 4 +1 +Variable +AOPT +Type +2 +A1 +F +3 +A2 +F +F +4 +H +F +4 +A3 +F +F +5 +AREA +F +5 +7 +EU +F +7 +8 +C +F +8 +THI1 +THI2 +F +7 +F +8 +F +6 +TA +F +6 +6 +7 +Variable +1 +V1 +Type +F +2 +V2 +F +3 +V3 +F +4 +D1 +F +5 +D2 +F +6 +D3 +F +*MAT_278 +7 +8 + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +VYARN +Type +F + Card 6 +Variable +1 +K1 +Type +F +2 +K2 +F +3 +C1 +F +4 +C2 +F +5 +M +F + Card 7 +1 +2 +3 +4 +5 +Variable +EXP1 +CHEXP2 +CHEXP3 +LCCHEX LCTHEXP0 +Type +F + Card 8 +1 +F +2 +F +3 +F +4 +F +5 +6 +N +F +6 +R +F +6 +7 +8 +7 +8 +TREFEXP ALPREEXP +F +7 +F +8 +Variable WLFTREF WLFA +WLFB +LCG0 +LCBULK0 +IDOC +XINCRM +Type +F +F +F +F +F +F +Viscoelastic Constant Cards. Up to 14 cards may be input. A keyword card (with a +“*” in column 1) terminates this input if less than 14 cards are used. The number of +terms for the shear behavior may differ from that for the bulk behavior: simply insert +zero if a term is not included. + Card 8 +Variable +Type +1 +GI +F +2 +BETAGI +F +3 +KI +F +4 +5 +6 +7 +8 +BETAKI +F + VARIABLE +DESCRIPTION +MID +RO +E1 +E2 +G12 +G23 +EU +C +EKA +EUA +VMB +Ekb +THL +TA +THI1 +THI2 +W +SPAN +THICK +H +Material identification. A unique number or label not exceeding +8 characters must be specified. +Mass density. +𝐸1, Young’s modulus in the yarn axial-direction. +𝐸2, Young’s modulus in the yarn transverse-direction. +𝐺12, Shear modulus of the yarns. +transverse shear modulus. +Ultimate strain at failure. +Coefficient of friction between the fibers. +Elastic constant of element "a". +Ultimate strain of element "a". +Damping coefficient of element "b". +Elastic constant of element "b" +Yarn locking angle. +Transition angle to locking. +Initial braid angle 1. +Initial braid angle 2. +Fiber width. +Span between the fibers. +Real fiber thickness. +Effective fiber thickness. +VARIABLE +DESCRIPTION +AREA +APOT +VYARN +K1 +K2 +C1 +C2 +M +N +CHEXP1 +CHEXP2 +CHEXP3 +LCCHEXP +LCTHEXP +R +TREFEXP +DOCREFEXP +Fiber cross-sectional area. +Material axes option . +Volume fraction of yarn +Parameter 𝑘1 for Kamal model. +Parameter 𝑘2 for Kamal model. +Parameter 𝑐1 for Kamal model. +Parameter 𝑐2 for Kamal model. +Exponent 𝑚 for Kamal model +Exponent 𝑛 for Kamal model. +Quadratic parameter 𝛾2 for chemical shrinkage. +Linear parameter 𝛾1 for chemical shrinkage. +Constant parameter 𝛾0 for chemical shrinkage. +Load curve ID to define the coefficient for chemical shrinkage +𝛾(𝛼) as a function of the state of cure 𝛼. If set, parameters +CHEXP1, CHEXP2 and CHEXP3 are ignored. +Load curve ID or table ID defining the instantaneous coefficient +of thermal expansion 𝛽(𝛼, 𝑇) as a function of cure 𝛼 and +temperature 𝑇. If referring to a load curve, parameter 𝛽(𝑇) is a +function of temperature 𝑇. +Gas constant 𝑅 for Kamal model. +Reference temperature 𝑇0 for secant form of thermal expansion. +Reference degree of cure 𝛼0 for sequential form of chemical +expansion. +WLFTREF +Reference temperature for WLF shift function. +WLFA +WLFB +LCG0 +LCK0 +Parameter 𝐴 for WLF shift function. +Parameter 𝐵 for WLF shift function. +Load curve ID defining the instantaneous shear modulus 𝐺0 as a +function of state of cure. +Load curve ID defining the instantaneous bulk modulus 𝐾0 as a +function of state of cure. +IDOC +Initial degree of cure. +*MAT_CF_MICROMECHANICS +DESCRIPTION +INCR +Switch between incremental and total stress formulation. +EQ.0: total form: (DEFAULT) +EQ.1: incremental form: (recommended) +GI +Shear relaxation modulus for the ith term for fully cured +material. +BETAGI +Shear decay constant for the ith term for fully cured material. +KI +Bulk relaxation modulus for the ith term for fully cured material. +BETAKI +Bulk decay constant for the ith term for fully cured material. +*MAT_279 +This is material type 279. This is a cohesive model for paper materials and can be used +only with cohesive element fomulations; see the variable ELFORM in *SECTION_SOL- +ID and *SECTION_SHELL. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +RO +ROFLG +INTFAIL +EN0 +ET0 +EN1 +ET1 +Type +A8 +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none + Card 2 +1 +Variable +T0N +2 +DN +3 +4 +T1N +T0T +Type +F +F +F +F +5 +DT +F +6 +7 +T1T +E3C +F +F +8 +CC +F +Default +none +none +none +none +none +none +none +none + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ASIG +BSIG +CSIG +FAILN +FAILT +Type +F +F +F +F +F +Default +none +none +none +none +none + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +RO +Mass density +ROFLG +Flag for whether density is specified per unit area or volume. +ROFLG.EQ.0: specified density per unit volume (default) +ROFLG.EQ.1: specifies the density +is per unit area for +controlling the mass of cohesive elements with +an initial volume of zero. +INTFAIL +The number of integration points required for the cohesive +element to be deleted. If it is zero, the element will not be deleted +even if it satisfies the failure criterion. The value of INTFAIL may +range from 1 to 4, with 1 the recommended value. +EN0 +EN1 +ET0 +ET1 +T0N +DN +T1N +T0T +DT +T1T +E3C +CC +ASIG +BSIG +The initial tensile stiffness (units of stress / length) normal to the +plane of the cohesive element. +The final tensile stiffness (units of stress / length) normal to the +plane of the cohesive element. +The initial stiffness (units of stress / length) tangential to the +plane of the cohesive element. +The final stiffness (units of stress / length) tangential to the plane +of the cohesive element. +Peak tensile traction in normal direction. +Scale factor (unit of length). +Final tensile traction in normal direction. +Peak tensile traction in tangential direction. If negative, the +absolute value indicates a curve with respect to the normal +traction. +Scale factor (unit of length). If negative, the absolute value +indicates a curve with respect to the normal stress. +Final traction in tangential direction. If negative, the absolute +value indicates a curve with respect to the normal traction. +Elastic parameter in normal compression. +Elastic parameter in normal compression. +Plasticity hardening parameter in normal compression. +Plasticity hardening parameter in normal compression. +𝑇 +𝑇0 +𝐸0 +𝐸(𝛿 ̅ +𝑝) +𝑇1 +Figure M279-1. Traction-separation law +CSIG +Plasticity hardening parameter in normal compression. +Maximum effective separation distance in normal direction. +Beyond this distance failure occurs. +Maximum effective separation distance in tangential direction. +Beyond this distance failure occurs. +FAILN +FAILT +Remarks: +In this elastoplastic cohesive material the normal and tangential directions are treated +separately, but can be connected by expressing the in-plane traction parameters as +functions of the normal traction. In the normal direction the material uses different +models in tension and compression. +Normal tension: +Assume the total separation is an additive split of the elastic and plastic separation +𝛿 = 𝛿𝑒 + 𝛿𝑝 . +In normal tension (𝛿𝑒 > 0) the elastic traction is given by +𝑇 = 𝐸𝛿𝑒 = 𝐸(𝛿 − 𝛿𝑝) ≥ 0, +where the tensile normal stiffness +𝐸 = (𝐸𝑁 +0 − 𝐸𝑁 +1 ) exp +−𝛿 ̅ +𝛿𝑁 ⎠ +⎟⎞ + 𝐸𝑁 +1 , +⎜⎛ +⎝ +depends on the effective plastic separation in the normal direction +Yield traction for tensile loads in normal direction is given by +𝛿 ̅ +𝑝 = ∫∣d𝛿𝑝∣ . +𝑇yield = (𝑇𝑁 +0 − 𝑇𝑁 +1 ) exp +⎜⎛ +⎝ +−𝛿 ̅ +𝛿𝑁 ⎠ +⎟⎞ + 𝑇𝑁 +1 ≥ 0, +and yielding occurs when 𝑇 > 𝑇yield ≥ 0. The above elastoplastic model gives the +traction-separation law depicted in Figure M279-1. +Normal compression: +In normal compression the elastic traction is +and the yield traction is +𝑇 = 𝐸3 +𝑐 [1 − exp(−𝐶𝑐𝛿𝑒)] ≤ 0, +𝑇yield = −[𝐴𝜎 + 𝐵𝜎 exp(−𝐶𝜎𝛿 ̅ +𝑝)] ≤ 0, +with yielding if 𝑇 < 𝑇yield ≤ 0. +Tangential traction: +Assume the total separation is an additive split of the elastic and plastic separation in +each in-plane direction +The elastic traction is given by +𝛿𝑖 = 𝛿𝑒 +𝑖 , +𝑖 + 𝛿𝑝 +𝑖 = 1,2. +where the tensile normal stiffness +𝑇𝑖 = 𝐸𝛿𝑒 +𝑖 = 𝐸(𝛿𝑖 − 𝛿𝑝 +𝑖 ), +𝐸 = (𝐸𝑇 +0 − 𝐸𝑇 +1 ) exp +−𝛿 ̅ +𝛿𝑇 ⎠ +⎟⎞ + 𝐸𝑇 +1 , +⎜⎛ +⎝ +depends on the effective plastic separation +𝛿 ̅ +𝑝 = ∫ d𝛿𝑝 , +d𝛿𝑝 = √(d𝛿𝑝 +1) +2) ++ (d𝛿𝑝 +. +Yield traction is given by +𝑇yield = (𝑇𝑇 +0 − 𝑇𝑇 +⎜⎛ +1 ) exp +⎝ +−𝛿 ̅ +𝛿𝑇 ⎠ +⎟⎞ + 𝑇𝑇 +1 , +and yielding occurs when +2 + 𝑇2 +𝑇1 +2 − 𝑇𝑦𝑖𝑒𝑙𝑑 +2 ≥ 0. +The plastic flow increment follows the flow rule +d𝛿𝑝 +𝑖 = +𝑇𝑖 +2 + 𝑇2 +√𝑇1 +d𝛿𝑝. +The above elastoplastic model gives the traction-separation law depicted in Figure +M279-1. +History variables +This material uses five history variables. Effective separation in the tangential direction +is saved as Effective Plastic Strain. History variable 1 and 2 indicates the plastic +separation in each tangential direction. Effective plastic separation and plastic +separation in the normal direction are saved as history variable 3 and 4, respectively. +*MAT_GLASS +This is Material Type 280. It is a smeared fixed crack model with a selection of different +brittle, stress-state dependent failure criteria such as Rankine, Mohr-Coulomb, or +Drucker-Prager. The model incorporates up to 2 (orthogonal) cracks per integration +point, simultaneous failure over element thickness, and crack closure effects. It is +available for shell elements and explicit analysis only. + Card 1 +1 +Variable +MID +2 +RO +Type +A8 +F + Card 2 +1 +Variable +FMOD +Type +F + Card 3 +1 +2 +FT +F +2 +3 +E +F +3 +FC +F +3 +4 +PR +F +4 +AT +F +4 +5 +6 +7 +8 +IMOD +ILAW +F +7 +BC +F +7 +F +8 +8 +5 +BT +F +5 +6 +AC +F +6 +Variable +SFSTI +SFSTR +CRIN +ECRCL +NCYCR +NIPF +Type +F +F +F +F +F +F + VARIABLE +DESCRIPTION +MID +RO +E +PR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Mass density 𝜌. +Young’s modulus 𝐸. +Poisson’s ratio 𝜈. +IMOD +*MAT_280 +DESCRIPTION +Flag to choose degradation procedure, when critical stress is +reached. +EQ.0.0: Softening in NCYCR load steps. Define SFSTI, SFSTR, +and NCYCR (default). +EQ.1.0: Damage model for softening. Define ILAW, AT, BT, +AC, and BC. +ILAW +Flag to choose damage evolution law if IMOD = 1.0, see Remarks. +EQ.0.0: Same damage evolution for tensile and compressive +failure (default). +EQ.1.0: Different damage evolution for tensile failure and +compressive failure. +FMOD +Flag to choose between failure criteria, see Remarks. +EQ.0.0: Rankine maximum stress (default), +EQ.1.0: Mohr-Coulomb, +EQ.2.0: Drucker-Prager. +Tensile strength 𝑓𝑡. +Compressive strength 𝑓𝑐. +Tensile damage evolution parameter 𝛼𝑡. Can be interpreted as the +residual load carrying capacity ratio for tensile failure ranging +from 0 to 1. +Tensile damage evolution parameter 𝛽𝑡. It controls the softening +velocity for tensile failure. +Compressive damage evolution parameter 𝛼𝑡. Can be interpreted +as the residual load carrying capacity ratio for compressive failure +ranging from 0 to 1. +Compressive damage evolution parameter 𝛽𝑡. It controls the +softening velocity for compressive failure. +Scale factor for stiffness after failure, e.g. SFSTI = 0.001 means that +stiffness is reduced to 0.1% of the elastic stiffness at failure. +Scale factor for stress in case of failure, e.g. SFSTR = 0.01 means +that stress is reduced to 1% of the failure stress at failure. +FT +FC +AT +BT +AC +BC +SFSTI +SFSTR +*MAT_GLASS +DESCRIPTION +ICRIN +Flag for crack strain initialization +EQ.0.0: initial crack strain is strain at failure (default), +EQ.1.0: initial crack strain is zero. +Crack strain necessary to reactivate certain stress components +after crack closure. +Number of cycles in which the stress is reduced to SFSTR*failure +stress. +Number of failed through thickness integration points to fail all +through thickness integration points for IMOD = 0. +ECRCL +NCYCR +NIPF +Remarks: +The underlying material behavior before failure is isotropic, small strain linear elasticity +with Young’s modulus 𝐸 and Poisson’s ratio 𝜈. Asymmetric (tension-compression +dependent) failure happens as soon as one of the following plane stress failure criteria is +violated. +For FMOD = 0, a maximum stress criterion (Rankine) is used, where principal stresses +𝜎1 and 𝜎2 are bound by tensile strength 𝑓𝑡 and compressive strength 𝑓𝑐 as follows: +−𝑓𝑐 < {𝜎1, 𝜎2} < 𝑓𝑡 +With FMOD = 1, the Mohr-Coulomb criterion with expressions in four different +categories is used: +𝜎1 > 0 and 𝜎2 > 0: max ( +𝜎1 < 0 and 𝜎2 < 0: max (− +𝜎1 +𝑓𝑡 +𝜎1 +𝑓𝑐 +, +𝜎2 +𝑓𝑡 +) < 1 +, − +𝜎2 +𝑓𝑐 +) < 1 +𝜎1 > 0 and 𝜎2 < 0: +− +< 1 +𝜎1 < 0 and 𝜎2 > 0: − ++ +< 1 +𝜎1 +𝑓𝑡 +𝜎1 +𝑓𝑐 +𝜎2 +𝑓𝑐 +𝜎2 +𝑓𝑡 +And for FMOD = 2, the plane stress Drucker-Prager criterion is given by +2𝑓𝑐 +[( +𝑓𝑐 +𝑓𝑡 +− 1) (𝜎1 + 𝜎2) + ( +𝑓𝑐 +𝑓𝑡 ++ 1) √𝜎1 +2 + 𝜎2 +2 − 𝜎1𝜎2] < 1 +As soon as failure happens in the tensile regime, a crack occurs perpendicular to the +maximum principal stress direction. That means a crack coordinate system is set up +and stored, defined by a relative angle with respect to the element coordinate system. +Appropriate stress and stiffness tensor components (e.g. normal to the crack) are +reduced according to SFSTR and SFSTI if IMOD = 0. The stress reduction takes place in +a period of NCYCR time step cycles. For IMOD = 1.0 the stress and stiffness tensor are +reduced by a damage model, please see below. A second crack orthogonal to the first +crack is possible which can open and close independently from the first one, further +reducing the element stiffness. +To deal with crack closure, the current strain in principal stress direction is stored as +initial crack strain (ICRIN = 0, default) or the initial crack strain is set to zero +(ICRIN = 1). After failure, the crack strain is tracked, so that later crack closure will be +detected. If that is the case, appropriate stress and stiffness tensor components (e.g. +compressive) are reactivated so that e.g. under pressure a load could be carried and +cause a nonzero stress perpendicular to the crack. +If the critical number of failed integration points (NIPF) in one element is reached, all +integration points over the element thickness fail as well. The default value of NIPF = 1 +resembles the fact, that a crack in a glass plate immediately runs through the thickness. +Starting with the Release of LS-DYNA version R10, a damage model for stress and +stiffness softening can be activated with IMOD = 1. The corresponding evolution law +for ILAW = 0 is given by +𝐷 = +{⎧ +{⎨ +⎩ +1 − +0 𝑓𝑜𝑟 𝜅 ≤ 𝜅0 +𝜅0 +(1 − 𝛼𝑡,𝑐 + 𝛼𝑡,𝑐𝑒−𝛽𝑡,𝑐 (𝜅−𝜅0)) 𝑒𝑙𝑠𝑒 +i.e. tensile and compressive failure are treated in the same fashion. +On the other hand, with ILAW = 1, the damage evolution for tensile failure is given by +𝐷 = +{⎧ +{⎨ +⎩ +0 𝑓𝑜𝑟 𝜅 ≤ 𝜅0 +𝜅0 +(1 − 𝛼𝑡 + 𝛼𝑡𝑒−𝛽𝑡 (𝜅−𝜅0)) 𝑒𝑙𝑠𝑒 +1 − +whereas damage for compressive failure evolves like that (more delayed stress +reduction): +𝐷 = +{⎧ +{⎨ +⎩ +0 𝑓𝑜𝑟 𝜅 ≤ 𝜅0 +𝜅0 +(1 − 𝛼𝑐) − 𝛼𝑐𝑒−𝛽𝑐 (𝜅−𝜅0) 𝑒𝑙𝑠𝑒 +1 − +*MAT_GLASS + VARIABLE +DESCRIPTION +1 +2 +3 +Crack flag: +0 = no crack, 1 = one crack, 2 = two cracks, -1 = failed under +compression +Direction of 1st principle stress as angle in radiant with respect to +the element direction. The shell normal defines the positive angle +direction. The 1st crack direction is perpendicular to the direction +of 1st principle stress. +Angle in radiant that defines the orthogonal to the 2nd crack +direction (with respect to the element direction). +*MAT_293 +This is Material Type 293. This material models the behavior of pre-impregnated +(prepreg) composite fibers during the high temperature preforming process. In +addition to providing stress and strain, it also provides warp and weft yarn directions +and stretch ratios after the forming process. The major applications of the model are for +materials used in light weight automobile parts. + Card 1 +1 +Variable +MID +Type +A8 + Card 2 +1 +2 +RO +F +2 +3 +ET +F +3 +4 +EC +F +4 +Variable +G124 +G125 +G126 +GAMMAL +Type +F + Card 3 +1 +F +2 +F +3 +F +4 +Variable +VM +EPSILON +THETA +BULK +Type +F +F +F +F +5 +PR +F +5 +VF +F +5 +G +F + VARIABLE +DESCRIPTION +6 +7 +8 +G121 +G122 +G123 +F +6 +F +7 +F +8 +EF3 +VF23 +EM +F +6 +F +7 +F +8 +MID +RO +ET +EC +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Continuum equivalent mass density. +Tensile modulus along the fiber yarns, corresponding to the slope +of the curve in Figure M293-2 in the Stable Modulus region from a +uniaxial tension test. See Remark 5. +Compression modulus along the fiber yarns, reversely calculated +using bending tests when all the other material properties are +determined. See Remark 5. +VARIABLE +DESCRIPTION +PR +G12i +Poisson’s ratio. See Remark 5. +Coefficients for the bias-extension angle change-engineering stress +curve in Figure M293-3. G121 to G126 corresponds to the 6th order +to 1st order factors of the loading curve. See Remark 5. +GAMMAL +Shear locking angle, in degrees. See Remark 5. +VF +EF3 +Fiber volume fraction in the prepreg composite. +Transverse compression modulus of the dry fiber. +VF23 +Transverse Poisson’s ratio of the dry fiber +EM +VM +EPSILON +THETA +Young’s modulus of the cured resin. +Poisson’s ratio of the cured resin +Stretch ratio at the end of undulation stage during the uniaxial +tension test. Example shown in Figure M293-2. See Remark 5. +Initial angle offset between the fiber direction and the element +direction. To reduce simulation error, when building the model, +the elements should be aligned to the same direction as much as +possible. +BULK +Bulk modulus of the prepreg material +G +Shear modulus of the prepreg material +Remarks: +1. Fiber and Resin Properties. The dry fiber properties, EF3 and VF23, and the +cure resin properties, EM and VM, are used to calculate the through thickness +elastic modulus of the prepreg using the rule of mixture. These properties will +not affect the in-plane deformation of the prepreg during the preforming +simulation. +2. Shear Locking. In most of the preforming cases, the angle between the fiber +yarns will not reach the shear locking state. This model is not designed for, +and, therefore, not recommended for simulating shear locking. +3. BULK and G. BULK and G are used by the contact algorithm. Changing these +parameters will not affect the final simulation result significantly (but it may +affect the time step). +4. Model Description. Woven composite prepregs are characterized using a non- +orthogonal coordinate system having two principal directions: one aligned with +the longitudinal warp yarns and the other with the transverse weft yarns. Prior +to deformation the warp and weft yarns are orthogonal. The directions and the +fiber stretch ratios are determined from the deformation gradient. In Figure +M293-1, the angles 𝛼 and 𝛽 refer to the relative of the rotation of the warp yarn +coordinate to the local corotational 𝑥 coordinate and the angle between the +warp and weft yarns, respectively [2,3,4]. +The stress from material deformation is divided into two parts: (1) stress caused +by the fiber stretch, 𝛔𝑓 , as shown in Figure M293-1 (a); (2) stress caused by the +fiber rotation, 𝛔𝑚, as shown in Figure M293-1 (b). The total stress tensor, 𝛔, in +the local corotational 𝑥 − 𝑦 coordinate system is the sum where the components +are given below [3]: +𝑓 = 𝜎𝑦𝑥 +𝜎𝑥𝑦 +𝜎𝑥𝑦 +𝑚 = 𝜎𝑦𝑥 +𝑓 sin 2(𝛼 + 𝛽) #(2) +𝜎2 +𝑓 = 𝜎1 +𝑓 cos2(𝛼 + 𝛽) #(1) +𝑓 cos2 𝛼 + 𝜎2 +𝜎𝑥𝑥 +𝑓 = +𝑓 sin 2𝛼 + +𝜎1 +𝑓 = 𝜎1 +𝑓 sin2(𝛼 + 𝛽) #(3) +𝑓 sin2 𝛼 + 𝜎2 +𝜎𝑦𝑦 +𝑚 − 𝜎2 +𝑚 + 𝜎2 +𝜎1 +𝜎1 +𝑚 − 𝜎2 +𝜎1 +𝑚 + 𝜎2 +𝜎1 +𝑓 + 𝜎𝑥𝑥 +sin(2𝛼 + 𝛽) #(5) +𝑚 − 𝜎2 +𝜎1 +𝜎𝑥𝑥 = 𝜎𝑥𝑥 +𝑚 #(7) +𝑚 = +𝑚 = +𝑚 = +𝜎𝑦𝑦 +𝜎𝑥𝑥 +− ++ +cos(2𝛼 + 𝛽) #(4) +cos(2𝛼 + 𝛽) #(6) +𝜎𝑥𝑦 = 𝜎𝑦𝑥 = 𝜎𝑥𝑦 +𝑓 + 𝜎𝑥𝑦 +𝑚 #(8) +𝜎𝑦𝑦 = 𝜎𝑦𝑦 +𝑓 + 𝜎𝑦𝑦 +𝑚 #(9) +5. Material Property Characterization. The non-orthogonal stress components +caused by yarn stretch and rotation at various deformation states will be char- +acterized via a set of experiments, which are uniaxial tension, bias-extension +and cantilever beam bending tests. All the tests need to be performed at the +preforming temperature. See references [1] and [3] for more details. +𝑦 +𝑓 +𝜎2 +𝑚 +𝜎2 +𝜎1 +𝛽 +𝛼 +(a) +𝑚 +𝜎1 +(b +) +Figure M293-1. Stress components caused by (a) stretch in fiber directions +and (b) rotation of the fibers [3]. +400 +350 +300 +250 +200 +150 +100 +50 +) +( +Undulation +region +Stable Modulus +region +0.00% 1.00% 2.00% 3.00% 4.00% 5.00% +Stretch Ratio +Figure M293-2. An example of the engineering stress as a function of stretch +ratio from the uniaxial tension test [3]. +The uniaxial tension test is used to obtain the fiber direction undulation strains +and the stable tensile moduli, together with the in-plane Poisson’s ratio (PR). A +typical test result is shown in Figure M293-2. From the stretch ratio- +engineering stress curve, the tensile modulus, ET, and the stretch ratio at the +end of undulation, EPSILON, can be captured. +The bias-extension test is used to characterize the shear behavior of the compo- +site needed for fields G12𝑖. The test procedure comes from the benchmark test +literature [1]. An example of the bias-extension test angle change-engineering +stress curve is shown in Figure M293-3. +) +( +0.1 +0.08 +0.06 +0.04 +0.02 +Curve fitting +0.2 +0.4 +1.0 +Angle change (radians) +0.6 +0.8 +1.2 +1.4 +Figure M293-3. An example of the angle change-engineering stress curve +from the bias-extension test. The curve fit for this example is 𝑦 = −0.29𝑥6 + +1.09𝑥5 − 1.68𝑥4 + 1.37𝑥3 − 0.56𝑥2 + 0.12𝑥 . For this example curve the inputs +into LS-DYNA are G121 = −0.29, G122 = 1.09, G123 = −1.68, G124 = 1.37, +G125 = −0.56, and G126 = −0.12 [3]. +Thermometer +Forming Temp +Ruler +Composite +Support & +Clamp +Heating Chamber +Figure M293-4. Bending test setup [3] +The angle change is calculated by using the equation [1]: +𝛾 = +− 2 cos−1 𝐷 + 𝑑 +√2𝐷 +where 𝑑 is the cross-head displacement and 𝐷 is the difference between the +original height and the original width of the sample. This equation holds only +before the shear locking angle, specified in field GAMMAL, which is measured +directly at the end of the test, so the curve should end when the fiber yarn angle +reaches the shear locking state. +The bending test should be performed to characterize the compression modulus +along the yarn directions, as specified in the EC field. The test setup is shown +in Figure M293-4. The composite specimen is held in a clamp and deforms +under its own gravity. During the test, the composite is heated to the preform- +ing temperature and the tip displacement is recorded. Due to the nonlinearity +of the tensile modulus, the compression modulus is reversely calculated using a +simulation: it is adjusted until the simulation leads to similar tip displacement +to the real experiment case. The starting point for the compression modulus +iteration can be set as about 100X of the shear modulus when the warp and weft +yarns are perpendicular to each other. +6. Element Type. The material model is available for shell elements with OSU=1 +and INN=2 in the CONTROL_ACCURACY card. It is recommended to use a +double precision version of LS-DYNA. +References: + [1] J. Cao, R. Akkerman, P. Boisse, J. Chen, H.S. Cheng, E.F. de Graaf, J.L. +Gorczyca, P. Harrison, G. Hivet, J. Launay, W. Lee, L. Liu, S.V. Lomov, A. +Long, E. de Luycker, F. Morestin, J. Padvoiskis, X.Q. Peng, J. Sherwood, Tz. +Stoilova, X.M. Tao, I. Verpoest, A. Willems, J. Wiggers, T.X. Yu, B. Zhu, +Characterization of mechanical behavior of woven fabrics: Experimental methods +and benchmark results, Composites Part A: Applied Science and Manufacturing, +Volume 39, Issue 6, 2008, Pages 1037-1053, ISSN 1359-835X. + [2] Pu Xue, Xiongqi Peng, Jian Cao, A non-orthogonal constitutive model for +characterizing woven composites, Composites Part A: Applied Science and +Manufacturing, Volume 34, Issue 2, 2003, Pages 183-193, ISSN 1359-835X. + [3] Weizhao Zhang, Huaqing Ren, Biao Liang, Danielle Zeng, Xuming Su, Jeffrey +Dahl, Mansour Mirdamadi, Qiangsheng Zhao, Jian Cao, A non-orthogonal +material model of woven composites in the preforming process, CIRP Annals - +Manufacturing Technology, Volume 66, Issue 1, 2017, Pages 257-260, ISSN 0007- +8506. + [4] X.Q. Peng, J. Cao, A continuum mechanics-based non-orthogonal constitutive +model for woven composite fabrics, Composites Part A: Applied Science and +Manufacturing, Volume 36, Issue 6, 2005, Pages 859-874, ISSN 1359-835X. +See *MAT_VACUUM or *MAT_140. +*MAT_ALE_01 +*MAT_ALE_GAS_MIXTURE +This may also be referred to as *MAT_ALE_02. This model is used to simulate +thermally equilibrated ideal gas mixtures. This only works with the multi-material ALE +formulation (ELFORM = 11 in *SECTION_SOLID). This keyword needs to be used +together with *INITIAL_GAS_MIXTURE for the initialization of gas densities and +temperatures. When applied in the context of ALE airbag modeling, the injection of +inflator gas is done with a *SECTION_POINT_SOURCE_MIXTURE command which +controls the injection process. This is an identical material model to the *MAT_GAS_- +MIXTURE model. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +IADIAB +RUNIV +Type +A8 +Default +none +Remark +I +0 +5 +F +0.0 +1 +Card 2 for Per mass Calculation. Method (A) RUNIV = blank or 0.0. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable CVmass1 CVmass2 CVmass3 CVmass4 CVmass5 CVmass6 CVmass7 Cvmass8 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +Card 3 for Per mass Calculation. Method (A) RUNIV = blank or 0.0. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable CPmass1 CPmass2 CPmass3 CPmass4 CPmass5 CPmass6 CPmass7 Cpmass8 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +Card 2 for Per Mole Cclculation. Method (B) RUNIV is nonzero. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable MOLWT1 MOLWT2 MOLWT3 MOLWT4 MOLWT5 MOLWT6 MOLWT7 MOLWT8 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +Remark +2 +Card 3 for Per Mole Cclculation. Method (B) RUNIV is nonzero. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CPmole1 CPmole2 CPmole3 CPmole4 CPmole5 CPmole6 Cpmole7 CPmole8 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +Remark +Card 4 for Per Mole Cclculation. Method (B) RUNIV is nonzero. + Card 4 +Variable +1 +B1 +Type +F +2 +B2 +F +3 +B3 +F +4 +B4 +F +5 +B5 +F +6 +B6 +F +7 +B7 +F +8 +B8 +F +Default +none +none +none +none +none +none +none +none +Remark +2 +Card 5 for Per Mole Cclculation. Method (B) RUNIV is nonzero. + Card 5 +Variable +1 +C1 +Type +F +2 +C2 +F +3 +C3 +F +4 +C4 +F +5 +C5 +F +6 +C6 +F +7 +C7 +F +8 +C8 +F +Default +none +none +none +none +none +none +none +none +Remark +2 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +IADIAB +This flag (default = 0) is used to turn ON/OFF adiabatic +compression logics for an ideal gas (remark 5). +EQ.0: OFF (default) +EQ.1: ON +RUNIV +Universal gas constant in per-mole unit (8.31447 J/(mole*K)). +CVmass1 - +CVmass8 +If RUNIV is BLANK or zero (method A): Heat capacity at +constant volume for up to eight different gases in per-mass unit. +VARIABLE +DESCRIPTION +CPmass1 - +CPmass8 +If RUNIV is BLANK or zero (method A): Heat capacity at +constant pressure for up to eight different gases in per-mass unit. +MOLWT1 - +MOLWT8 +If RUNIV is nonzero (method B): Molecular weight of each ideal +gas in the mixture (mass-unit/mole). +If RUNIV is nonzero (method B): Heat capacity at constant +pressure for up to eight different gases in per-mole unit. These +are nominal heat capacity values typically at STP. These are +denoted by the variable “A” in the equation in remark 2. +If RUNIV is nonzero (method B): First order coefficient for a +temperature dependent heat capacity at constant pressure for up +to eight different gases. These are denoted by the variable “B” in +the equation in remark 2. +If RUNIV is nonzero (method B): Second order coefficient for a +temperature dependent heat capacity at constant pressure for up +to eight different gases. These are denoted by the variable “C” in +the equation in remark 2. +CPmole1 - +CPmole8 +B1 - B8 +C1 - C8 +Remarks: +1. There are 2 methods of defining the gas properties for the mixture. If RUNIV is +BLANK or ZERO → Method (A) is used to define constant heat capacities +where per-mass unit values of Cv and Cp are input. Only cards 2 and 3 are +required for this method. Method (B) is used to define constant or temperature +dependent heat capacities where per-mole unit values of Cp are input. Cards 2- +5 are required for this method. +2. The per-mass-unit, temperature-dependent, constant-pressure heat capacity is +𝐶𝑝(𝑇) = +(CPMOLE + B × 𝑇 + C × 𝑇2) +MOLWT +Typical metric units: +𝐶𝑝(𝑇) +kg 𝐾 +CPMOLE +A +mole K +mole K2 +mole K3 +3. The initial temperature and the density of the gas species present in a mesh or +part at time zero is specified by the keyword *INITIAL_GAS_MIXTURE. +4. The ideal gas mixture is assumed to be thermal equilibrium, that is, all species +are at the same temperature (T). The gases in the mixture are also assumed to +follow Dalton’s Partial Pressure Law, +ngas +𝑃 = ∑ 𝑃𝑖 +. +The partial pressure of each gas is then +𝑃𝑖 = 𝜌𝑖𝑅gas𝑖 +𝑇 +Where +𝑅gas𝑖 += +𝑅univ +MOLWT +. +The individual gas species temperature equals the mixture temperature. The +temperature is computed from the internal energy where the mixture internal +energy per unit volume is used, +whence +𝑇 = 𝑇𝑖 = +𝑒𝑉 +ngas +∑ 𝜌𝑖𝐶𝑉𝑖 +ngas +𝑒𝑉 = ∑ 𝜌𝑖𝐶𝑉𝑖 +ngas +𝑇𝑖 += ∑ 𝜌𝑖𝐶𝑉𝑖 +𝑇. +In general, the advection step conserves momentum and internal energy, but +not kinetic energy. This can result in energy lost in the system and lead to a +pressure drop. In *MAT_GAS_MIXTURE the dissipated kinetic energy is au- +tomatically stored in the internal energy. Thus in effect the total energy is con- +served instead of conserving just the internal energy. This numerical scheme +has been shown to improve accuracy in some cases. However, the user should +always be vigilant and check the physics of the problem closely. +5. As an example consider an airbag surrounded by ambient air. As the inflator +gas flows into the bag, the ALE elements cut by the airbag fabric shell elements +will contain some inflator gas inside and some ambient air outside. The multi- +material element treatment is not perfect. Consequently the temperature of the +outside air may, occasionally, be made artificially high after the multi-material +element treatment. To prevent the outside ambient air from getting artificially +high T, set IDIAB = 1 for the ambient air outside. Simple adiabatic compression +equation is then assumed for the outside air. The use of this flag may be need- +ed, but only when that outside air is modeled by the *MAT_GAS_MIXTURE +card. +Example: +Consider a tank test model where the Lagrangian tank (Part S1) is surrounded by an +ALE air mesh (Part H4 = AMMGID 1). There are 2 ALE parts which are defined but +initially have no corresponding mesh: part 5 (H5 = AMMGID 2) is the resident gas +inside the tank at t = 0, and part 6 (H6 = AMMGID 2) is the inflator gas(es) which is +injected into the tank when t > 0. AMMGID stands for ALE Multi-Material Group ID. +Please see figure and input below. The *MAT_GAS_MIXTURE (MGM) card defines the +gas properties of ALE parts H5 & H6. The MGM card input for both method (A) and +(B) are shown. +The *INITIAL_GAS_MIXTURE card is also shown. It basically specifies that “AM- +MGID 2 may be present in part or mesh H4 at t = 0, and the initial density of this gas is +defined in the rho1 position which corresponds to the 1st material in the mixture (or H5, +the resident gas).” +Example configuration: +Cut-off view +S1 = tank +H4 = AMMG1 = backgrou +nd outside air (initially +defined ALE mesh) +H5 = AMMG2 = initial +gas +inside the tank (this has no +initial mesh) +H6 = AMMG2 = inflator +gas(es) injected in (this has no +initial mesh) +Sample input: +$------------------------------------------------------------------------------- +*PART +H5 = initial gas inside the tank +$ PID SECID MID EOSID HGID GRAV ADPOPT TMID + 5 5 5 0 5 0 0 +*SECTION_SOLID + 5 11 0 +$------------------------------------------------------------------------------- +$ Example 1: Constant heat capacities using per-mass unit. +$*MAT_GAS_MIXTURE +$ MID IADIAB R_univ +$ 5 0 0 +$ Cv1_mas Cv2_mas Cv3_mas Cv4_mas Cv5_mas Cv6_mas Cv7_mas Cv8_mas +$718.7828911237.56228 +$ Cp1_mas Cp2_mas Cp3_mas Cp4_mas Cp5_mas Cp6_mas Cp7_mas Cp8_mas +$1007.00058 1606.1117 +$------------------------------------------------------------------------------- +$ Example 2: Variable heat capacities using per-mole unit. +*MAT_GAS_MIXTURE +$ MID IADIAB R_univ + 5 0 8.314470 +$ MW1 MW2 MW3 MW4 MW5 MW6 MW7 MW8 + 0.0288479 0.02256 +$ Cp1_mol Cp2_mol Cp3_mol Cp4_mol Cp5_mol Cp6_mol Cp7_mol Cp8_mol + 29.049852 36.23388 +$ B1 B2 B3 B4 B5 B6 B7 B8 + 7.056E-3 0.132E-1 +$ C1 C2 C3 C4 C5 C6 C7 C8 + -1.225E-6 -0.190E-5 +$------------------------------------------------------------------------------- +$ One card is defined for each AMMG that will occupy some elements of a mesh set +*INITIAL_GAS_MIXTURE +$ SID STYPE MMGID T0 + 4 1 1 298.15 +$ RHO1 RHO2 RHO3 RHO4 RHO5 RHO6 RHO7 RHO8 +1.17913E-9 +*INITIAL_GAS_MIXTURE +$ SID STYPE MMGID T0 + 4 1 2 298.15 +$ RHO1 RHO2 RHO3 RHO4 RHO5 RHO6 RHO7 RHO8 +1.17913E-9 +$------------------------------------------------------------------------------- +F +0.0 +*MAT_ALE_VISCOUS +*MAT_ALE_VISCOUS +*MAT_ALE_03 +This may also be referred to as MAT_ALE_03. This “fluid-like” material model is very +similar to Material Type 9 (*MAT_NULL). It allows the modeling of non-viscous fluids +with constant or variable viscosity. The variable viscosity is a function of an equivalent +deviatoric strain rate. If inviscid material is modeled, the deviatoric or viscous stresses +are zero, and the equation of state supplies the pressures (or diagonal components of +the stress tensor). All *MAT_ALE_cards apply only to ALE element formulation. + Card 1 +1 +Variable +MID +Type +I +2 +RO +F +3 +PC +F +4 +5 +6 +7 +8 +MULO +MUHI +RK +Not used +RN +F +F +F +Defaults +none +none +0.0 +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +MID +Material identification. A unique number has to be chosen. +RO +PC +Mass density. +Pressure cutoff (≤ 0.0). See Remark 4. +MULO +There are 4 possible cases : +1. +2. +3. +4. +If MULO = 0.0, then inviscid fluid is assumed. +If MULO > 0.0, and MUHI = 0.0 or is not defined, then +this is the traditional constant dynamic viscosity coeffi- +cient 𝜇. +If MULO > 0.0, and MUHI > 0.0, then MULO and MUHI +are lower and upper viscosity limit values for a power- +law-like variable viscosity model. +If MULO is negative (for example, MULO = -1), then a +user-input data load curve (with LCID = 1) defining dy- +namic viscosity as a function of equivalent strain rate is +used. +VARIABLE +DESCRIPTION +MUHI +There are 2 possible cases: +5. +6. +in +If MUHI < 0.0, then the viscosity can be defined by the +file dyn21.F with a routine called +user +f3dm9ale_userdef1. The file is part of the general us- +ermat package. +the +If MUHI > 0.0, then this is the upper dynamic viscosity +limit (default = 0.0). This is defined only if RK and RN +are defined for the variable viscosity case. +Variable dynamic viscosity multiplier. See Remark 6. +Variable dynamic viscosity exponent. See Remark 6. +RK +RN +Remarks: +1. Deviatoric Viscous Stress. The null material must be used with an equation- +of-state. Pressure cutoff is negative in tension. A (deviatoric) viscous stress of +the form +𝜎𝑖𝑗 +′ +′ = 2𝜇𝜀̇𝑖𝑗 +[ +𝑚2] ~ [ +𝑚2 𝑠] [ +] +is computed for nonzero 𝜇 where 𝜀̇𝑖𝑗 +namic viscosity. For example, in SI unit system, 𝜇 has a unit of [Pa × s]. +′ is the deviatoric strain rate. 𝜇 is the dy- +2. Hourglass Control Issues. The null material has no shear stiffness and +hourglass control must be used with care. In some applications, the default +hourglass coefficient might lead to significant energy losses. In general for +fluid(s), the hourglass coefficient QM should be small (in the range 10−4 to 10−6 +for the standard default IHQ choice). +3. Null Material Properties. Null material has no yield strength and behaves in a +fluid-like manner. +4. Numerical Cavitation. The pressure cut-off, PC, must be defined to allow for a +material to “numerically” cavitate. In other words, when a material undergoes +dilatation above certain magnitude, it should no longer be able to resist this +dilatation. Since dilatation stress or pressure is negative, setting PC limit to a +very small negative number would allow for the material to cavitate once the +pressure in the material goes below this negative value. +5. +Issues with Small Values of Viscosity Exponent. If the viscosity exponent is +less than 1.0, RN < 1.0, then RN − 1.0 < 0.0. In this case, at very low equivalent +strain rate, the viscosity can be artificially very high. MULO is then used as the +viscosity value. +6. Empirical Dynamic Viscosity. The empirical variable dynamic viscosity is +typically modeled as a function of equivalent shear rate based on experimental +data. +For an incompressible fluid, this may be written equivalently as +μ(𝛾̅̅̅̅̇ ′) = RK × 𝛾̅̅̅̅̇ ′(𝑅𝑁−1) +μ(𝜀̅ +̇′) = RK × 𝜀̅ +̇′(𝑅𝑁−1) +The “overbar” denotes a scalar equivalence. The “dot” denotes a time deriva- +tive or rate effect. And the “prime” symbol denotes deviatoric or volume pre- +serving components. The equivalent shear rate components may be related to the +basic definition of (small-strain) strain rate components as follows: +𝜀̇𝑖𝑗 = +( +∂𝑢𝑖 +∂𝑥𝑗 ++ +∂𝑢𝑗 +∂𝑥𝑖 +𝛾̇𝑖𝑗 = 2𝜀̇𝑖𝑗 +) ⇒ 𝜀̇𝑖𝑗 +′ = 𝜀̇𝑖𝑗 − 𝛿𝑖𝑗 ( +𝜀̇𝑘𝑘 +) +Typically, the 2nd invariant of the deviatoric strain rate tensor is defined as: +The equivalent (small-strain) deviatoric strain rate is defined as: +𝐼2𝜀̅ +̇′ = +[𝜀̇𝑖𝑗 +′ 𝜀̇𝑖𝑗 +′ ] +𝜀̅′̇ ≡ 2√𝐼2𝜀′̇ = √2[𝜀̇𝑖𝑗 +′ 𝜀̇𝑖𝑗 +′ ] = √4[𝜀̇12 +′ 2 + 𝜀̇23 +′ 2 + 𝜀̇31 +′ 2] + 2[𝜀̇11 +′ 2 + 𝜀̇22 +′ 2 + 𝜀̇33 +′ 2] +In non-Newtonian literatures, the equivalent shear rate is sometimes defined as +𝛾̅̅̅̅̇ ≡ √ +𝛾̇𝑖𝑗𝛾̇𝑖𝑗 += √2𝜀̇𝑖𝑗𝜀̇𝑖𝑗 = √4[𝜀̇12 +2 + 𝜀̇23 +2 + 𝜀̇31 +2 ] + 2[𝜀̇11 +2 + 𝜀̇22 +2 + 𝜀̇33 +2 ] +It turns out that, (a) for incompressible materials (𝜀̇𝑘𝑘 = 0), and (b) the shear +′ , the equivalent shear rate is algebraical- +terms are equivalent when 𝑖 ≠ 𝑗→ 𝜀̇𝑖𝑗 = 𝜀̇𝑖𝑗 +ly equivalent to the equivalent (small-strain) deviatoric strain rate. +̇′ = 𝛾̅̅̅̅̇ ′ +𝜀̅ +*MAT_ALE_MIXING_LENGTH +This may also be referred to as *MAT_ALE_04. This viscous “fluid-like” material model +is an advanced form of *MAT_ALE_VISCOUS. It allows the modeling of fluid with +constant or variable viscosity and a one-parameter mixing-length turbulence model. +The variable viscosity is a function of an equivalent deviatoric strain rate. The equation +of state supplies the pressures for the stress tensor. All *MAT_ALE_cards apply only to +ALE element formulation. +Card Format + Card 1 +1 +Variable +MID +Type +I +2 +RO +F +3 +PC +F +4 +5 +6 +7 +8 +MULO +MUHI +RK +Not used +RN +F +F +F +Defaults +none +0.0 +0.0 +0.0 +0.0 +0.0 +Internal Flow Card. + Card 2 +Variable +1 +LC +Type +F +2 +C0 +F +3 +C1 +F +4 +C2 +F +5 +C3 +F +6 +C4 +F +7 +C5 +F +F +0.0 +8 +C6 +F +Defaults +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +External Flow Card. + Card 3 +Variable +1 +LC +Type +F +2 +D0 +F +3 +D1 +F +4 +D2 +F +5 +E0 +F +6 +E1 +F +7 +E2 +F +8 +Defaults +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +VARIABLE +DESCRIPTION +MID +Material identification. A unique number has to be chosen. +Mass density +Pressure cutoff (≤ 0.0). +There are 3 possible cases: (1) If MULO > 0.0, and MUHI = 0.0 or +is not defined, then this is the traditional constant dynamic +viscosity coefficientμ. (2) If MULO > 0.0, and MUHI > 0.0, then +MULO and MUHI are lower and upper viscosity limit values. (3) +If MULO is negative (for example, MULO = -1), then a user-input +data load curve (with LCID = 1) defining dynamic viscosity as a +function of equivalent strain rate is used. +Upper dynamic viscosity limit (default = 0.0). This is defined +only if RK and RN are defined for the variable viscosity case. +Variable dynamic viscosity multiplier. The viscosity is computed +as μ(𝜀̇′̅̅̅̅̅̅) = 𝑟𝑘 ⋅ 𝜀̇′̅̅̅̅̅̅(𝑟𝑛−1) where the equivalent deviatoric strain rate +is +̅̅̅̅̅̅ = √ +𝜀′̇ +[𝜀̇11 +′ 2 + 𝜀̇22 +′ 2 + 𝜀̇33 +′ 2 + 2(𝜀̇12 +′ 2 + 𝜀̇23 +′ 2 + 𝜀̇31 +′ 2)] +Variable dynamic viscosity exponent . +Characteristic length, 𝑙ci, of the internal turbulent domain. +Internal flow mixing length polynomial coefficients. The one- +parameter turbulent mixing length is computed as +𝑙𝑐𝑖 +⎡𝐶0 + 𝐶1 (1 − +⎢ +⎣ +) + ⋯ + 𝐶6 (1 − +𝑙m = 𝑙ci +𝑙𝑐𝑖 +) +⎤ +⎥ +⎦ +Characteristic length, 𝑙cx, of the external turbulent domain. +External flow mixing length polynomial coefficients. If 𝑦 ≤ 𝑙cx +then the mixing length is computed as 𝑙𝑚 = [𝐷0 + 𝐷1𝑦 + 𝐷2𝑦2] +External flow mixing length polynomial coefficients. If 𝑦 > 𝑙cx +then the mixing length is computed as 𝑙𝑚 = [𝐸0 + 𝐸1𝑦 + 𝐸2𝑦2] +RO +PC +MULO +MUHI +RK +RN +LCI +C0 - C6 +LCX +D0 - D2 +E0 - E2 +Remarks: +1. The null material must be used with an equation of-state. Pressure cutoff is +negative in tension. A (deviatoric) viscous stress of the form +′ +𝜎′𝑖𝑗 = 𝜇𝜀̇𝑖𝑗 +𝑚2] ≈ [ +is computed for nonzero 𝜇 where 𝜀̇𝑖𝑗 +namic viscosity with unit of [Pa × s]. +[ +] +𝑚2 𝑠] [ +′ is the deviatoric strain rate. 𝜇 is the dy- +2. The null material has no shear stiffness and hourglass control must be used +with care. In some applications, the default hourglass coefficient might lead to +significant energy losses. In general for fluid(s), the hourglass coefficient QM +should be small (in the range 10−4 to 10−6 for the standard default IHQ choice). +3. The Null material has no yield strength and behaves in a fluid-like manner. +4. The pressure cut-off, PC, must be defined to allow for a material to “numerical- +ly” cavitate. In other words, when a material undergoes dilatation above cer- +tain magnitude, it should no longer be able to resist this dilatation. Since +dilatation stress or pressure is negative, setting PC limit to a very small negative +number would allow for the material to cavitate once the pressure in the mate- +rial goes below this negative value. +5. +If the viscosity exponent is less than 1.0, at very low equivalent strain rate, the +viscosity can be artificially very high. MULO is then used as the viscosity val- +ue. +6. Turbulence is treated simply by considering its effects on viscosity. Total +effective viscosity is the sum of the laminar and turbulent viscosities, +𝜇eff = 𝜇𝑙 + 𝜇𝑡 where 𝜇eff is the effective viscosity, and 𝜇𝑡 is the turbulent viscosi- +ty. +7. The turbulent viscosity is computed based on the Prandtl’s Mixing Length +Model, +𝜇𝑡 = ρ𝑙𝑚 +2 |∇𝐯| +*MAT_ALE_INCOMPRESSIBLE +See *MAT_160. +*MAT_ALE_HERSCHEL +This may also be referred to as MAT_ALE_06. This is the Herschel-Buckley model. It is +an enhancement to the power law viscosity model in *MAT_ALE_VISCOUS(*MAT_- +ALE_03). Two additional input parameters: the yield stress threshold and critical shear +strain rate can be specified to model “rigid-like” material for low strain rates. +It allows the modeling of non-viscous fluids with constant or variable viscosity. The +variable viscosity is a function of an equivalent deviatoric strain rate. All *MAT_- +ALE_cards apply only to ALE element formulation. + Card 1 +1 +Variable +MID +Type +I +2 +RO +F +3 +PC +F +4 +5 +6 +7 +8 +MULO +MUHI +RK +Not used +RN +F +F +F +Defaults +none +none +0.0 +0.0 +0.0 +0.0 +F +0.0 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +GDOTC +TAO0 +Type +F +F +Default +none +none + VARIABLE +DESCRIPTION +MID +Material identification. A unique number has to be chosen. +RO +PC +Mass density. +Pressure cutoff (≤ 0.0), . +VARIABLE +DESCRIPTION +MULO +There are 4 possible cases : +1. +2. +3. +4. +If MULO = 0.0, then inviscid fluid is assumed. +If MULO > 0.0, and MUHI = 0.0 or is not defined, then +this is the traditional constant dynamic viscosity coeffi- +cient 𝜇. +If MULO > 0.0, and MUHI > 0.0, then MULO and MUHI +are lower and upper viscosity limit values for a power- +law-like variable viscosity model. +If MULO is negative (for example, MULO = -1), then a +user-input data load curve (with LCID = 1) defining dy- +namic viscosity as a function of equivalent strain rate is +used. +Upper dynamic viscosity limit (default = 0.0). This is defined +only if RK and RN are defined for the variable viscosity case. +𝑘; consistency factor . +𝑛; power law index . +MUHI +RK +RN +GDOTC +𝛾̇𝑐; critical shear strain rate . +TAO0 +𝜏0; yield stress . +Remarks: +1. The null material must be used with an equation-of-state. Pressure cutoff is +negative in tension. A (deviatoric) viscous stress of the form +𝜎′𝑖𝑗 = 2𝜇𝜀′̇ +𝑚2 𝑠] [ +𝑚2] ~ [ +is computed for nonzero 𝜇 where 𝜀′̇ +𝑖𝑗 is the deviatoric strain rate. 𝜇 is the dy- +namic viscosity. For example, in SI unit system, 𝜇 has a unit of [Pa*s]. +𝑖𝑗 +] +[ +2. The null material has no shear stiffness and hourglass control must be used +with care. In some applications, the default hourglass coefficient might lead to +significant energy losses. In general for fluid(s), the hourglass coefficient QM +should be small (in the range 1.0E-4 to 1.0E-6 for the standard default IHQ +choice). +3. Null material has no yield strength and behaves in a fluid-like manner. +4. The pressure cut-off, PC, must be defined to allow for a material to “numerical- +ly” cavitate. In other words, when a material undergoes dilatation above cer- +tain magnitude, it should no longer be able to resist this dilatation. Since +dilatation stress or pressure is negative, setting PC limit to a very small negative +number would allow for the material to cavitate once the pressure in the mate- +rial goes below this negative value. +5. +If the viscosity exponent is less than 1.0, 𝑅𝑁 < 1.0, then 𝑅𝑁 − 1.0 < 0.0. In this +case, at very low equivalent strain rate, the viscosity can be artificially very +high. MULO is then used as the viscosity value. +6. The Herschel-Buckley model employs a large viscosity to model the “rigid-like” +behavior for low shear strain rates (𝛾̇ < 𝛾̇𝑐). +Power law is used once the yield stress is passed. +𝜇 = 𝜇0 +μ(𝛾̇) = +𝜏0 +𝛾̇ ++ 𝑘( +𝛾̇ +𝛾̇𝑐 +)𝑛−1 +The shear strain rate is: +𝛾̅̅̅̅̇ ≡ √ +𝛾̇𝑖𝑗𝛾̇𝑖𝑗 += √2𝜀̇𝑖𝑗𝜀̇𝑖𝑗 = √4[𝜀̇12 +2 + 𝜀̇23 +2 + 𝜀̇31 +2 ] + 2[𝜀̇11 +2 + 𝜀̇22 +2 ] +2 + 𝜀̇33 +*MAT_SPH_VISCOUS +This may also be referred to as MAT_SPH_01. This “fluid-like” material model is very +similar to Material Type 9 (*MAT_NULL). It allows the modeling of viscous fluids with +constant or variable viscosity. The variable viscosity is a function of an equivalent +deviatoric strain rate. If inviscid material is modeled, the deviatoric or viscous stresses +are zero, and the equation of state supplies the pressures (or diagonal components of +the stress tensor). + Card 1 +1 +Variable +MID +Type +I +2 +RO +F +3 +PC +F +4 +5 +MULO +MUHI +F +F +6 +RK +F +7 +RC +F +8 +RN +F +Defaults +none +none +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +MID +Material identification. A unique number has to be chosen. +RO +PC +Mass density. +Pressure cutoff (≤ 0.0). See Remark 4. +MULO +There are 4 possible cases : +1. +2. +3. +4. +If MULO = 0.0, then inviscid fluid is assumed. +If MULO > 0.0, and MUHI = 0.0 or is not defined, then +this is the traditional constant dynamic viscosity coeffi- +cient 𝜇. +If MULO > 0.0, and MUHI > 0.0, then MULO and MUHI +are lower and upper viscosity limit values for a power- +law-like variable viscosity model. +If MULO is negative (for example, MULO = -1), then a +user-input data load curve (with LCID = 1) defining dy- +namic viscosity as a function of equivalent strain rate is +used. +VARIABLE +DESCRIPTION +MUHI +There are 2 possible cases: +5. +6. +If MUHI < 0.0, then the viscosity can be defined by the +user in the file dyn21.F with a routine called f3dm9sph_ +userdefin. The file is part of the general usermat package. +If MUHI > 0.0, then this is the upper dynamic viscosity +limit (default = 0.0). This is defined only if RK and RN +are defined for the variable viscosity case. +RK +RC +Variable dynamic viscosity multiplier. See Remark 6. +Option for Cross viscosity model: See Remark 7. +RC > 0.0: Cross viscosity model will be used (overwrite all +other options), values of MULO, MUHI, RK and RN +will be used in the Cross viscosity model. See Re- +mark 7. +RC ≤ 0.0: other viscosity model (decided based on above +variables) will be used. +RN +Variable dynamic viscosity exponent. See Remark 6. +Remarks: +1. Deviatoric Viscous Stress. The null material must be used with an equation- +of-state. Pressure cutoff is negative in tension. A (deviatoric) viscous stress of +the form +′ +′ = 2𝜇𝜀̇𝑖𝑗 +𝜎𝑖𝑗 +[ +𝑚2] ~ [ +𝑚2 𝑠] [ +] +is computed for nonzero 𝜇 where 𝜀̇𝑖𝑗 +namic viscosity. For example, in SI unit system, 𝜇 has a unit of [Pa × s]. +′ is the deviatoric strain rate. 𝜇 is the dy- +2. Hourglass Control Issues. The null material has no shear stiffness and +hourglass control must be used with care. In some applications, the default +hourglass coefficient might lead to significant energy losses. In general for +fluid(s), the hourglass coefficient QM should be small (in the range 10−4 to 10−6 +for the standard default IHQ choice). +3. Null Material Properties. Null material has no yield strength and behaves in a +fluid-like manner. +4. Numerical Cavitation. The pressure cut-off, PC, must be defined to allow for a +material to “numerically” cavitate. In other words, when a material undergoes +dilatation above certain magnitude, it should no longer be able to resist this +dilatation. Since dilatation stress or pressure is negative, setting PC limit to a +very small negative number would allow for the material to cavitate once the +pressure in the material goes below this negative value. +5. +Issues with Small Values of Viscosity Exponent. If the viscosity exponent is +less than 1.0, RN < 1.0, then RN − 1.0 < 0.0. In this case, at very low equivalent +strain rate, the viscosity can be artificially very high. MULO is then used as the +viscosity value. +6. Empirical Dynamic Viscosity. The empirical variable dynamic viscosity is +typically modeled as a function of equivalent shear rate based on experimental +data. +For an incompressible fluid, this may be written equivalently as +μ(𝛾̅̅̅̅̇ ′) = RK × 𝛾̅̅̅̅̇ ′(𝑅𝑁−1) +μ(𝜀̅ +̇′) = RK × 𝜀̅ +̇′(𝑅𝑁−1) +The “overbar” denotes a scalar equivalence. The “dot” denotes a time deriva- +tive or rate effect. And the “prime” symbol denotes deviatoric or volume pre- +serving components. The equivalent shear rate components may be related to the +basic definition of (small-strain) strain rate components as follows: +𝜀̇𝑖𝑗 = +( +∂𝑢𝑖 +∂𝑥𝑗 ++ +∂𝑢𝑗 +∂𝑥𝑖 +𝛾̇𝑖𝑗 = 2𝜀̇𝑖𝑗 +) ⇒ 𝜀̇𝑖𝑗 +′ = 𝜀̇𝑖𝑗 − 𝛿𝑖𝑗 ( +𝜀̇𝑘𝑘 +) +Typically, the 2nd invariant of the deviatoric strain rate tensor is defined as: +The equivalent (small-strain) deviatoric strain rate is defined as: +𝐼2𝜀̅ +̇′ = +[𝜀̇𝑖𝑗 +′ 𝜀̇𝑖𝑗 +′ ] +𝜀̅′̇ ≡ 2√𝐼2𝜀′̇ = √2[𝜀̇𝑖𝑗 +′ 𝜀̇𝑖𝑗 +′ ] = √4[𝜀̇12 +′ 2 + 𝜀̇23 +′ 2 + 𝜀̇31 +′ 2] + 2[𝜀̇11 +′ 2 + 𝜀̇22 +′ 2 + 𝜀̇33 +′ 2] +In non-Newtonian literatures, the equivalent shear rate is sometimes defined as +𝛾̅̅̅̅̇ ≡ √ +𝛾̇𝑖𝑗𝛾̇𝑖𝑗 += √2𝜀̇𝑖𝑗𝜀̇𝑖𝑗 = √4[𝜀̇12 +2 + 𝜀̇23 +2 + 𝜀̇31 +2 ] + 2[𝜀̇11 +2 + 𝜀̇22 +2 + 𝜀̇33 +2 ] +It turns out that, (a) for incompressible materials (𝜀̇𝑘𝑘 = 0), and (b) the shear +′ , the equivalent shear rate is algebraical- +terms are equivalent when 𝑖 ≠ 𝑗→ 𝜀̇𝑖𝑗 = 𝜀̇𝑖𝑗 +ly equivalent to the equivalent (small-strain) deviatoric strain rate. +̇′ = 𝛾̅̅̅̅̇ ′ +𝜀̅ +7. The Cross viscous model is one of simplest and most used model for shear- +thinning behavior, i.e., the fluid’s viscosity decreases with increasing of the +local shear rate 𝛾̅̅̅̅̇, thus the dynamic viscosity μ is defined as a function of 𝛾̅̅̅̅̇: +μ(𝛾̅̅̅̅̇ ′) = MUHI + (MULO − MUHI)/(1.0 + RK ∗ 𝛾̅̅̅̅̇ ′)𝑅𝑁−1 +Where RK and RN are two positive fitting parameters, and MULO, MUHI are +the limiting values of the viscosity at low and high shear rates, respectively. +RK, RN, MULO and MUHI are parameters from keyword input. +*MAT_S01 +This is Material Type 1 for discrete elements (*ELEMENT_DISCRETE). This provides a +translational or rotational elastic spring located between two nodes. Only one degree of +freedom is connected. +3 +4 +5 +6 +7 +8 + Card 1 +1 +Variable +MID +Type +A8 +2 +K +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +K +Elastic stiffness (force/displacement) or (moment/rotation). +*MAT_DAMPER_VISCOUS +This is Material Type 2 for discrete elements (*ELEMENT_DISCRETE). This material +provides a linear translational or rotational damper located between two nodes. Only +one degree of freedom is then connected. +3 +4 +5 +6 +7 +8 + Card 1 +1 +Variable +MID +2 +DC +Type +A8 +F + VARIABLE +DESCRIPTION +MID +DC +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Damping +constant +ment/rotation rate). +(force/displacement +rate) +or +(mo- +*MAT_S03 +This is Material Type 3 for discrete elements (*ELEMENT_DISCRETE). This material +provides an elastoplastic translational or rotational spring with isotropic hardening +located between two nodes. Only one degree of freedom is connected. + Card 1 +1 +Variable +MID +Type +A8 +2 +K +F +3 +KT +F +4 +FY +F +5 +6 +7 +8 + VARIABLE +DESCRIPTION +MID +K +KT +FY +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Elastic stiffness (force/displacement) or (moment/rotation). +Tangent stiffness (force/displacement) or (moment/rotation). +Yield (force) or (moment). +*MAT_SPRING_NONLINEAR_ELASTIC +This is Material Type 4 for discrete elements (*ELEMENT_DISCRETE). This material +provides a nonlinear elastic translational and rotational spring with arbitrary force +versus displacement and moment versus rotation, respectively. Optionally, strain rate +effects can be considered through a velocity dependent scale factor. With the spring +located between two nodes, only one degree of freedom is connected. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +LCD +LCR +Type +A8 +I +I + VARIABLE +DESCRIPTION +MID +LCD +LCR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Load curve ID describing force versus displacement or moment +versus rotation relationship. The load curve must define the +response in the negative and positive quadrants and pass through +point (0,0). +Optional load curve describing scale factor on force or moment as +a function of relative velocity or. rotational velocity, respectively. +*MAT_DAMPER_NONLINEAR_VISCOUS +This is Material Type 5 for discrete elements (*ELEMENT_DISCRETE). This material +provides a viscous translational damper with an arbitrary force versus velocity +dependency, or a rotational damper with an arbitrary moment versus rotational +velocity dependency. With the damper located between two nodes, only one degree of +freedom is connected. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +LCDR +Type +A8 +I + VARIABLE +DESCRIPTION +MID +LCDR +Material identification. A unique number or label not exceeding 8 +characters must be specified. +identification describing +force versus rate-of- +Load curve +displacement relationship or a moment versus rate-of-rotation +relationship. The load curve must define the response in the +negative and positive quadrants and pass through point (0,0). +*MAT_SPRING_GENERAL_NONLINEAR +This is Material Type 6 for discrete elements (*ELEMENT_DISCRETE). This material +provides a general nonlinear translational or rotational spring with arbitrary loading +and unloading definitions. Optionally, hardening or softening can be defined. With the +spring located between two nodes, only one degree of freedom is connected. + Card 1 +1 +2 +3 +4 +Variable +MID +LCDL +LCDU +BETA +5 +TYI +6 +CYI +7 +8 +Type +A8 +I +I +F +F +F + VARIABLE +DESCRIPTION +MID +LCDL +LCDU +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Load curve +force/torque versus +displacement/rotation relationship for loading, see Figure M26-1. +identification describing +identification describing +Load curve +force/torque versus +displacement/rotation relationship for unloading, see Figure +M119-1. +BETA +Hardening parameter, 𝛽: +EQ.0.0: Tensile and compressive yield with strain softening +(negative or zero slope allowed in the force versus dis- +placement. load curves). TYI and CYI are not imple- +mented for this option. +NE.0.0: Kinematic hardening without strain softening. +EQ.1.0: Isotropic hardening without strain softening. +Initial yield force in tension ( > 0) +Initial yield force in compression ( < 0) +TYI +CYI +Remarks: +Load curve points are in the format (displacement, force or rotation, moment). The +points must be in order starting with the most negative (compressive) displacement or +rotation and ending with the most positive (tensile) value. The curves need not be +symmetrical. +The displacement origin of the “unloading” curve is arbitrary, since it will be shifted as +necessary as the element extends and contracts. On reverse yielding the “loading” +curve will also be shifted along the displacement re or. rotation axis. The initial tensile +and compressive +Yield forces (TYI and CYI) define a range within which the element remains elastic (i.e. +the “loading” curve is used for both loading and unloading). If at any time the force in +the element exceeds this range, the element is deemed to have yielded, and at all +subsequent times the “unloading” curve is used for unloading +Figure MS6-1. General Nonlinear material for discrete elements +*MAT_SPRING_MAXWELL +This is Material Type 7 for discrete elements (*ELEMENT_DISCRETE). This material +provides a three Parameter Maxwell Viscoelastic translational or rotational spring. +Optionally, a cutoff time with a remaining constant force/moment can be defined. + Card 1 +1 +Variable +MID +Type +A8 +2 +K0 +F +3 +KI +F +4 +BETA +F +Default +5 +TC +F +1020 +6 +FC +F +0 +7 +8 +COPT +F +0 + VARIABLE +DESCRIPTION +MID +K0 +KI +Material identification. A unique number or label not exceeding 8 +characters must be specified. +𝐾0, short time stiffness +𝐾∞, long time stiffness +BETA +Decay parameter. +TC +FC +Cut off time. After this time a constant force/moment is +transmitted. +Force/moment after cutoff time +COPT +Time implementation option: +EQ.0: incremental time change, +NE.0: continuous time change. +Remarks: +The time varying stiffness K(t) may be described in terms of the input parameters as +𝐾(𝑇) = 𝐾∞ + (𝐾0 − 𝐾∞)exp (−𝛽t) +This equation was implemented by Schwer [1991] as either a continuous function of +time or incrementally following the approach of Herrmann and Peterson [1968]. The +continuous function of time implementation has the disadvantage of the energy +absorber’s resistance decaying with increasing time even without deformation. The +advantage of the incremental implementation is that an energy absorber must undergo +some deformation before its resistance decays, i.e., there is no decay until impact, even +in delayed impacts. The disadvantage of the incremental implementation is that very +rapid decreases in resistance cannot be easily matched. +*MAT_SPRING_INELASTIC +This is Material Type 8 for discrete elements (*ELEMENT_DISCRETE). This material +provides an inelastic tension or compression only, translational or rotational spring. +Optionally, a user-specified unloading stiffness can be taken instead of the maximum +loading stiffness. + Card 1 +1 +2 +Variable +MID +LCFD +Type +A8 +I +3 +KU +F +4 +CTF +F +5 +6 +7 +8 + VARIABLE +DESCRIPTION +MID +LCFD +KU +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Load curve +identification describing arbitrary force/torque +versus displacement/rotation relationship. This curve must be +defined in the positive force-displacement quadrant regardless of +whether the spring acts in tension or compression. +Unloading stiffness (optional). The maximum of KU and the +maximum loading stiffness in the force/displacement or the +moment/rotation curve is used for unloading. +CTF +Flag for compression/tension: +EQ.-1.0: tension only, +EQ.0.0: default is set to 1.0, +EQ.1.0: compression only. +*MAT_SPRING_TRILINEAR_DEGRADING +This is Material Type 13 for discrete elements (*ELEMENT_DISCRETE). This material +allows concrete shearwalls to be modeled as discrete elements under applied seismic +loading. It represents cracking of the concrete, yield of the reinforcement and overall +failure. Under cyclic loading, the stiffness of the spring degrades but the strength does +not. + Card 1 +1 +2 +Variable +MID +DEFL1 +Type +A8 +F +3 +F1 +F +4 +DEFL2 +F +5 +F2 +F +6 +DEFL3 +F +7 +F3 +F +8 +FFLAG +F + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +DEFL1 +Deflection at point where concrete cracking occurs. +F1 +Force corresponding to DEFL1 +DEFL2 +Deflection at point where reinforcement yields +F2 +Force corresponding to DEFL2 +DEFL3 +Deflection at complete failure +F3 +Force corresponding to DEFL3 +FFLAG +Failure flag. +*MAT_SPRING_SQUAT_SHEARWALL +This is Material Type 14 for discrete elements (*ELEMENT_DISCRETE). This material +allows squat shear walls to be modeled using discrete elements. The behavior model +captures concrete cracking, reinforcement yield, ultimate strength followed by +degradation of strength finally leading to collapse. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID +A14 +B14 +C14 +D14 +E14 +LCID +FSD +Type +A8 +F +F +F +F +F +I +F + VARIABLE +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +Material coefficient 𝐴 +Material coefficient 𝐵 +Material coefficient 𝐶 +Material coefficient 𝐷 +Material coefficient 𝐸 +Load curve ID referencing the maximum strength envelope curve +Sustained strength reduction factor +MID +A14 +B14 +C14 +D14 +E14 +LCID +FSD +Remarks: +Material coefficients 𝐴, 𝐵, 𝐶 and 𝐷 are empirically defined constants used to define the +shape of the polynomial curves which govern the cyclic behavior of the discrete +element. A different polynomial relationship is used to define the loading and +unloading paths allowing energy absorption through hysteresis. Coefficient E is used +in the definition of the path used to “jump” from the loading path to the unloading path +(or vice versa) where a full hysteresis loop is not completed. The load curve referenced +is used to define the force displacement characteristics of the shear wall under +monotonic loading. This curve is the basis to which the polynomials defining the cyclic +behavior refer to. Finally, on the second and subsequent loading / unloading cycles, +the shear wall will have reduced strength. The variable FSD is the sustained strength +reduction factor. +*MAT_SPRING_MUSCLE +This is Material Type 15 for discrete elements (*ELEMENT_DISCRETE). This material +is a Hill-type muscle model with activation. It is for use with discrete elements. The +LS-DYNA implementation is due to Dr. J. A. Weiss. + Card 1 +1 +Variable +MID +Type +A8 +2 +L0 +F +3 +VMAX +F +Default +1.0 +4 +SV +F +1.0 +5 +A +F +6 +FMAX +F +7 +TL +F +8 +TV +F +1.0 +1.0 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FPE +LMAX +KSH +Type +F +F +F +Default +0.0 + VARIABLE +MID +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +characters must be specified. +L0 +Initial muscle length, 𝐿0. +VMAX +Maximum CE shortening velocity, 𝑉max. +SV +Scale factor, 𝑆𝑣, for 𝑉max vs. active state. +LT.0: absolute value gives load curve ID +GE.0: constant value of 1.0 is used +A +Activation level vs. time function 𝑎(𝑡). +LT.0: absolute value gives load curve ID +GE.0: constant value of A is used +VARIABLE +DESCRIPTION +FMAX +Peak isometric force, 𝐹max. +TL +Active tension vs. length function, 𝑓TL(𝐿). +LT.0: absolute value gives load curve ID +GE.0: constant value of 1.0 is used +TV +Active tension vs. velocity function, 𝑓TV(𝑉). +LT.0: absolute value gives load curve ID +GE.0: constant value of 1.0 is used +FPE +Force vs. length function, 𝑓PE, for parallel elastic element. +LT.0: absolute value gives load curve ID +EQ.0: exponential function is used +GT.0: constant value of 0.0 is used +Relative length when 𝐹PE reaches 𝐹max. Required if 𝐹PE above. +Constant, 𝐾sh, governing the exponential rise of𝐹PE. Required if +𝐹PE above. +LMAX +KSH +Remarks: +The material behavior of the muscle model is adapted from the original model +proposed by Hill [1938]. Reviews of this model and extensions can be found in Winters +[1990] and Zajac [1989]. The most basic Hill-type muscle model consists of a contractile +element (CE) and a parallel elastic element (PE) (Figure MS15-1). An additional series +elastic element (SEE) can be added to represent tendon compliance. +The main assumptions of the Hill model are that the contractile element is entirely +stress free and freely distensible in the resting state, and is described exactly by Hill’s +equation (or some variation). When the muscle is activated, the series and parallel +elements are elastic, and the whole muscle is a simple combination of identical +sarcomeres in series and parallel. The main criticism of Hill’s model is that the division +of forces between the parallel elements and the division of extensions between the series +elements is arbitrary, and cannot be made without introducing auxiliary hypotheses. +However, these criticisms apply to any discrete element model. Despite these +limitations, the Hill model has become extremely useful for modeling musculoskeletal +dynamics, as illustrated by its widespread use today. +a(t) +SEE +FM +FCE +FPE +LM +vM +CE +FM +LM +PE +Figure MS15-1. Discrete model for muscle contraction dynamics, based on a +Hill-type representation. The total force is the sum of passive force 𝐹PE and +active force 𝐹CE. The passive element (PE) represents energy storage from +muscle elasticity, while the contractile element (CE) represents force +generation by the muscle. The series elastic element (SEE), shown in dashed +lines, is often neglected when a series tendon compliance is included. Here, +𝑎(𝑡) is the activation level, 𝐿M is the length of the muscle, and 𝑉M is the +shortening velocity of the muscle. +When the contractile element (CE) of the Hill model is inactive, the entire resistance to +elongation is provided by the PE element and the tendon load-elongation behavior. As +activation is increased, force then passes through the CE side of the parallel Hill model, +providing the contractile dynamics. The original Hill model accommodated only full +activation - this limitation is circumvented in the present implementation by using the +modification suggested by Winters (1990). The main features of his approach were to +realize that the CE force-velocity input force equals the CE tension-length output force. +This yields a three-dimensional curve to describe the force-velocity-length relationship +of the CE. If the force-velocity y-intercept scales with activation, then given the +activation, length and velocity, the CE force can be determined. +Without the SEE, the total force in the muscle FM is the sum of the force in the CE and +the PE because they are in parallel: +𝐹M = 𝐹PE + 𝐹CE +The relationships defining the force generated by the CE and PE as a function of 𝐿M, 𝑉M +and 𝑎(𝑡) are often scaled by 𝐹max, the peak isometric force (p. 80, Winters 1990), 𝐿0, the +initial length of the muscle (p. 81, Winters 1990), and 𝑉max, the maximum unloaded CE +shortening velocity (p. 80, Winters 1990). From these, dimensionless length and +velocity can be defined: +𝐿 = +𝐿M +𝐿0 +, +𝑉 = +𝑉M +𝑉max × 𝑆𝑣[𝑎(𝑡)] +Here, 𝑆𝑣 scales the maximum CE shortening velocity 𝑉max and changes with activation +level 𝑎(𝑡). This has been suggested by several researchers, i.e. Winters and Stark [1985]. +The activation level specifies the level of muscle stimulation as a function of time. Both +have values between 0 and 1. The functions 𝑆𝑣(𝑎(𝑡)) and 𝑎(𝑡) are specified via load +curves in LS-DYNA, or default values of 𝑆v = 1 and 𝑎(𝑡) = 0 are used. Note that 𝐿 is +always positive and that 𝑉 is positive for lengthening and negative for shortening. +The relationship between 𝐹CE, 𝑉 and 𝐿 was proposed by Bahler et al. [1967]. A three- +dimensional relationship between these quantities is now considered standard for +computer implementations of Hill-type muscle models [Winters 1990]. It can be written +in dimensionless form as: +𝐹CE = 𝑎(𝑡) × 𝐹max × 𝑓TL(𝐿) × 𝑓TV(𝑉) +Here, 𝑓TL(𝐿) and 𝑓TV(𝑉) are the tension-length and tension-velocity functions for active +skeletal muscle. Thus, if current values of 𝐿M, 𝑉M, and 𝑎(𝑡) are known, then 𝐹CE can be +determined (Figure MS15-1). +The force in the parallel elastic element 𝐹PE is determined directly from the current +length of the muscle using an exponential relationship [Winters 1990]: +𝑓PE = +𝐹PE +𝐹MAX += +⎧ +{ +{ +⎨ +{ +{ +⎩ +𝐿 ≤ 1 +exp(𝐾sh) − 1 +{exp [ +𝐾sh +𝐿max +(𝐿 − 1)] − 1} 𝐿 > 1 +Here, 𝐿max is the relative length at which the force 𝐹max occurs, and 𝐾sh is a +dimensionless shape parameter controlling the rate of rise of the exponential. +Alternatively, the user can define a custom 𝑓PE curve giving tabular values of +normalized force versus dimensionless length as a load curve. +For computation of the total force developed in the muscle 𝐹M, the functions for the +tension-length 𝑓TL(𝐿) and force-velocity fTV relationships used in the Hill element must +be defined. These relationships have been available for over 50 years, but have been +refined to allow for behavior such as active lengthening. The active tension-length +curve 𝑓TL(𝐿) describes the fact that isometric muscle force development is a function of +length, with the maximum force occurring at an optimal length. According to Winters, +this optimal length is typically around 𝐿 = 1.05, and the force drops off for shorter or +longer lengths, approaching zero force for 𝐿 = 0.4 and 𝐿 = 1.5. Thus the curve has a +bell-shape. Because of the variability in this curve between muscles, the user must +specify the function 𝑓𝑇𝐿(𝐿) via a load curve, specifying pairs of points representing the +normalized force (with values between 0 and 1) and normalized length 𝐿. See Figure +MS15-2. +Figure MS15-2. Typical normalized tension-length (TL) and tension-velocity +(TV) curves for skeletal muscle. +The active tension-velocity relationship 𝑓TV(𝑉) used in the muscle model is mainly due +to the original work of Hill. Note that the dimensionless velocity 𝑉 is used. When +𝑉 = 0, the normalized tension is typically chosen to have a value of 1.0. When 𝑉 is +greater than or equal to 0, muscle lengthening occurs. As 𝑉 increases, the function is +typically designed so that the force increases from a value of 1.0 and asymptotes +towards a value near 1.4 ass shown in Figure MS15-2. When 𝑉 is less than zero, muscle +shortening occurs and the classic Hill equation hyperbola is used to drop the +normalized tension to 0 as shown in Figure MS15-2. The user must specify the function +𝑓TV(𝑉) via a load curve, specifying pairs of points representing the normalized tension +(with values between 0 and 1) and normalized velocity 𝑉 +Available options include: +2D +Purpose: Define a seat belt material. +*MAT_B01 + Card 1 +1 +2 +3 +4 +5 +6 +7 +Variable +MID +MPUL +LLCID +ULCID +LMIN +CSE +DAMP +Type +A8 +Default +0 +F +0. +I +0 +I +0 +F +F +F +0.0 +0.0 +0.0 +0.0 +8 +E +F +Bending/Compression Parameter Card. Additional card for E.GT.0. + Card 2 +Variable +Type +1 +A +F +2 +I +F +3 +J +F +Default +0.0 +0.0 +2*I +4 +AS +F +A +8 +5 +F +F +6 +M +F +7 +R +F +1.0e20 1.0e20 +0.05 +Additional card for 2D option + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +P1DOFF +Type +Default +I +VARIABLE +DESCRIPTION +MID +MPUL +LLCID +ULCID +LMIN +CSE +Belt material number. A unique number or label not exceeding 8 +characters must be specified. +Mass per unit length +Curve or table ID for loading. LLCID can be either a single curve +(force vs. engineering strain), or a table defining a set of strain- +rate dependent loading curves. +Load curve identification for unloading (force vs. engineering +strain). +Minimum length (for elements connected to slip rings and +retractors), see notes below. +Optional compressive stress elimination option which applies to +shell elements only (default 0.0): +EQ.0.0: eliminate compressive stresses in shell fabric +EQ.1.0: do not eliminate compressive stresses. This option +should not be used if retractors and slip rings are pre- +sent in the model. +EQ.2.0: whether or not compressive stress is eliminated is +decided by LS-DYNA automatically, recommended for +shell belt. +DAMP +Optional Rayleigh damping coefficient, which applies to shell +elements only. A coefficient value of 0.10 is the default +corresponding to 10% of critical damping. Sometimes smaller or +larger values work better. +E +A +I +J +Young’s modulus for bending/compression stiffness, when +positive the optional card is invoked. See remarks. +Cross sectional area for bending/compression stiffness, see +remarks. +Area moment of inertia for bending/compression stiffness, see +remarks. +Torsional constant +remarks. +for bending/compression stiffness, see +AS +Shear area for bending/compression stiffness, see remarks. +VARIABLE +DESCRIPTION +Maximum force in compression/tension, see remarks. +Maximum torque, see remarks. +Rotational mass scaling factor, see remarks. +Part ID offset for internally created 1D, bar-type, belt parts for 2D +seatbelt of this material, i.e., the IDs of newly created 1D belt +parts will be P1DOFF + 1, P1DOFF + 2, … If zero, the maximum +ID of user-defined parts is used as the part ID offset. +F +M +R +P1DOFF +Remarks: +Each belt material defines stretch characteristics and mass properties for a set of belt +elements. The user enters a load curve for loading, the points of which are (Strain, +Force). Strain is defined as engineering strain, i.e. +Strain = +current length +initial length +− 1.0 +Another similar curve is entered to describe the unloading behavior. Both load curves +should start at the origin (0,0) and contain positive force and strain values only. The +belt material is tension only with zero forces being generated whenever the strain +becomes negative. The first non-zero point on the loading curve defines the initial yield +point of the material. On unloading, the unloading curve is shifted along the strain axis +until it crosses the loading curve at the “yield” point from which unloading commences. +If the initial yield has not yet been exceeded or if the origin of the (shifted) unloading +curve is at negative strain, the original loading curves will be used for both loading and +unloading. If the strain is less than the strain at the origin of the unloading curve, the +belt is slack and no force is generated. Otherwise, forces will then be determined by the +unloading curve for unloading and reloading until the strain again exceeds yield after +which the loading curves will again be used. +A small amount of damping is automatically included. This reduces high frequency +oscillation, but, with realistic force-strain input characteristics and loading rates, does +not significantly alter the overall forces-strain performance. The damping forced +opposes the relative motion of the nodes and is limited by stability: +𝐷 = +0.1 × mass × relative velocity + time step size +In addition, the magnitude of the damping force is limited to one-tenth of the force +calculated from the force-strain relationship and is zero when the belt is slack. +Damping forces are not applied to elements attached to sliprings and retractors. +The user inputs a mass per unit length that is used to calculate nodal masses on +initialization. +A “minimum length” is also input. This controls the shortest length allowed in any +element and determines when an element passes through sliprings or are absorbed into +the retractors. One tenth of a typical initial element length is usually a good choice. +Bending and Compression Stiffness for 1D Elements: +Since these elements do not possess any bending or compression stiffness, when belts +are used in an implicit analysis, dynamic analysis is mandatory. However, one +dimensional belt elements can be used in implicit statics by associating them with +bending/compression properties as per the first optional card. Two dimensional belt +elements are not supported with this feature. +To achieve bending and compression stiffness in 1D belts the belt element is overlayed +with a Belytschko-Schwer beam element with circular cross section. +These elements have 6 degrees of freedom including rotational degrees of freedom. The +material used in this context is an elastic-ideal-plastic material where the elastic part is +governed by the Young’s modulus E. Two yield values, F being the maximum +compression/tension force and M being the maximum torque, are used as upper +bounds for the resultants. The bending/compression forces and moments from this +contribution are accumulated to the force from the seatbelt itself. Since the main +purpose is to eliminate the singularities in bending and compression, it is recommend- +ed to choose the bending and compression properties in the optional card carefully so +as to not significantly influence the overall response. +For the sake of completeness, this feature is also supported by the explicit integrator; +therefore, a rotational nodal mass is needed. Each of the two nodes of an element gets a +contribution from the belt that is calculated as RMASS = R × (MASS/2) × I/A, where +MASS indicates the total translational mass of the belt element and R is a scaling factor +input by the user. The translational mass is not modified. The bending and +compression properties do not affect the stable time step. If the belts are used without +sliprings, then incorporating this feature is virtually equivalent to adding Belytschko- +Schwer beams on top of conventional belt elements as part of a modelling strategy. If +sliprings are used, this feature is necessary to properly support the flow of material +through the sliprings and swapping of belt elements across sliprings. Retractors cannot +be used with this feature. +*MAT_THERMAL_{OPTION} +Available options include: +ISOTROPIC +ORTHOTROPIC +ISOTROPIC_TD +ORTHOTROPIC_TD +DISCRETE_BEAM +CWM +ORTHOTROPIC_TD_LC +ISOTROPIC_PHASE_CHANGE +ISOTROPIC_TD_LC +USER_DEFINED +The *MAT_THERMAL_cards allow thermal properties to be defined in coupled +structural/thermal and thermal only analyses, see *CONTROL_SOLUTION. Thermal +properties must be defined for all elements in such analyses. +Thermal material properties are specified by a thermal material ID number (TMID), this +number is independent of the material ID number (MID) defined on all other *MAT_… +property cards. In the same analysis identical TMID and MID numbers may exist. The +TMID and MID numbers are related through the *PART card. +*MAT_THERMAL_ISOTROPIC +This is thermal material type 1. It allows isotropic thermal properties to be defined. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TMID +TRO +TGRLC +TGMULT +TLAT +HLAT +F +3 +F +4 +F +5 +F +6 +7 +8 +Type +A8 +F + Card 2 +Variable +1 +HC +Type +F +2 +TC +F + VARIABLE +TMID +DESCRIPTION +Thermal material identification. A unique number or label not +exceeding 8 characters must be specified. +TRO +Thermal density: +EQ.0.0: default to structural density. +TGRLC +Thermal generation rate curve number, see *DEFINE_CURVE: +GT.0: function versus time, +EQ.0: use constant multiplier value, TGMULT, +LT.0: function versus temperature. +TGMULT +Thermal generation rate multiplier: +EQ.0.0: no heat generation. +Phase change temperature +Latent heat +Specific heat +Thermal conductivity +TLAT +HLAT +HC +TC +*MAT_THERMAL_ORTHOTROPIC +This is thermal material type 2. It allows orthotropic thermal properties to be defined. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TMID +TRO +TGRLC +TGMULT +AOPT +TLAT +HLAT +Type +A8 +F +F +F +F +5 +5 +A2 +F +5 +F +6 +6 +A3 +F +6 +F +7 +8 +7 +8 +7 +8 +4 +K3 +F +4 +A1 +F +4 +2 +K1 +F +2 +YP +F +2 +D2 +F +3 +K2 +F +3 +ZP +F +3 +D3 +F + Card 2 +Variable +1 +HC +Type +F + Card 3 +Variable +1 +XP +Type +F + Card 4 +Variable +1 +D1 +Type +F + VARIABLE +TMID +DESCRIPTION +Thermal material identification. A unique number or label not +exceeding 8 characters must be specified. +TRO +Thermal density: +EQ.0.0: default to structural density. +*MAT_THERMAL_ORTHOTROPIC +DESCRIPTION +TGRLC +Thermal generation rate curve number, see *DEFINE_CURVE: +GT.0: function versus time, +EQ.0: use constant multiplier value, TGMULT, +LT.0: function versus temperature. +TGMULT +Thermal generation rate multiplier: +EQ.0.0: no heat generation. +AOPT +Material axes definition: +EQ.0.0: locally orthotropic with material axes by element +nodes N1, N2 and N4, +EQ.1.0: locally orthotropic with material axes determined by a +point in space and global location of element center, +EQ.2.0: globally orthotropic with material axes determined by +TLAT +HLAT +HC +K1 +K2 +K3 +vectors. +Phase change temperature +Latent heat +Specific heat +Thermal conductivity K1 in local x-direction +Thermal conductivity K2 in local y-direction +Thermal conductivity K3 in local z-direction +XP, YP, ZP +Define coordinate of point p for AOPT = 1 +A1, A2, A3 +Define components of vector a for AOPT = 2 +D1, D2, D3 +Define components of vector v for AOPT = 2 +*MAT_THERMAL_ISOTROPIC_TD +This is thermal material type 3. It allows temperature dependent isotropic properties to +be defined. The temperature dependency is defined by specifying a minimum of two +and a maximum of eight data points. The properties must be defined for the +temperature range that the material will see in the analysis. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TMID +TRO +TGRLC +TGMULT +TLAT +HLAT +Type +A8 +F +F +F +F +F + Card 2 +Variable +1 +T1 +Type +F + Card 3 +Variable +1 +C1 +Type +F + Card 4 +Variable +1 +K1 +Type +F + VARIABLE +TMID +2 +T2 +F +2 +C2 +F +2 +K2 +F +3 +T3 +F +3 +C3 +F +3 +K3 +F +4 +T4 +F +4 +C4 +F +4 +K4 +F +5 +T5 +F +5 +C5 +F +5 +K5 +F +6 +T6 +F +6 +C6 +F +6 +K6 +F +7 +T7 +F +7 +C7 +F +7 +K7 +F +8 +T8 +F +8 +C8 +F +8 +K8 +F +DESCRIPTION +Thermal material identification. A unique number or label not +exceeding 8 characters must be specified. +*MAT_THERMAL_ISOTROPIC_TD +DESCRIPTION +TRO +Thermal density: +EQ.0.0 default to structural density. +TGRLC +Thermal generation rate curve number, see *DEFINE_CURVE: +GT.0: function versus time, +EQ.0: use constant multiplier value, TGMULT, +LT.0: function versus temperature. +TGMULT +Thermal generation rate multiplier: +EQ.0.0: no heat generation. +TLAT +HLAT +Phase change temperature +Latent heat +T1, …, T8 +Temperatures: T1, ..., T8 +C1, …, C8 +Specific heat at: T1, …, T8 +K1, …, K8 +Thermal conductivity at: T1, …, T8 +*MAT_THERMAL_ORTHOTROPIC_TD +This is thermal material type 4. It allows temperature dependent orthotropic properties +to be defined. The temperature dependency is defined by specifying a minimum of two +and a maximum of eight data points. The properties must be defined for the +temperature range that the material will see in the analysis. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TMID +TRO +TGRLC +TGMULT +AOPT +TLAT +HLAT +Type +A8 +F +F +F +F +F +F + Card 2 +Variable +1 +T1 +Type +F + Card 3 +Variable +1 +C1 +Type +F + Card 4 +1 +2 +T2 +F +2 +C2 +F +2 +3 +T3 +F +3 +C3 +F +3 +4 +T4 +F +4 +C4 +F +4 +5 +T5 +F +5 +C5 +F +5 +6 +T6 +F +6 +C6 +F +6 +7 +T7 +F +7 +C7 +F +7 +8 +T8 +F +8 +C8 +F +8 +Variable +(K1)1 +(K1)2 +(K1)3 +(K1)4 +(K1)5 +(K1)6 +(K1)7 +(K1)8 +Type +F + Card 5 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +F +7 +F +8 +Variable +(K2)1 +(K2)2 +(K2)3 +(K2)4 +(K2)5 +(K2)6 +(K2)7 +(K2)8 +Type +F +F +F +F +F +F +F +Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +(K3)1 +(K3)2 +(K3)3 +(K3)4 +(K3)5 +(K3)6 +(K3)7 +(K3)8 +Type +F +F +F +F +F +F +F +7 +F +8 +7 +8 +4 +A1 +F +4 +5 +A2 +F +5 +6 +A3 +F +6 +2 +YP +F +2 +D2 +F +3 +ZP +F +3 +D3 +F + Card 7 +Variable +1 +XP +Type +F + Card 8 +Variable +1 +D1 +Type +F + VARIABLE +TMID +DESCRIPTION +Thermal material identification. A unique number or label not +exceeding 8 characters must be specified. +TRO +Thermal density: +EQ.0.0: default to structural density. +TGRLC +Thermal generation rate curve number, see *DEFINE_CURVE: +GT.0: function versus time, +EQ.0: use constant multiplier value, TGMULT, +LT.0: function versus temperature. +TGMULT +Thermal generation rate multiplier: +EQ.0.0: no heat generation. +VARIABLE +AOPT +DESCRIPTION +Material axes definition: : +EQ.0.0: locally orthotropic with material axes by element +nodes N1, N2 and N4, +EQ.1.0: locally orthotropic with material axes determined by a +point in space and global location of element center, +EQ.2.0: globally orthotropic with material axes determined by +vectors. +TLAT +HLAT +Phase change temperature +Latent heat +T1 ... T8 +Temperatures: T1 ... T8 +C1 ... C8 +Specific heat at T1 ... T8 +(K1)1 ... +(K1)8 +(K2)1 ... +(K2)8 +(K3)1 ... +(K3)8 +Thermal conductivity K1 in local x-direction at T1 ... T8 +Thermal conductivity K2 in local y-direction at T1 ... T8 +Thermal conductivity K3 in local z-direction at T1 ... T8 +XP, YP, ZP +Define coordinate of point p for AOPT = 1 +A1, A2, A3 +Define components of vector a for AOPT = 2 +D1, D2, D3 +Define components of vector d for AOPT = 2 +*MAT_THERMAL_DISCRETE_BEAM +This is thermal material type 5. It defines properties for discrete beams. It is only +applicable when used with *SECTION_BEAM elform = 6. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TMID +TRO +Type +A8 +F + Card 2 +Variable +1 +HC +Type +F +2 +TC +F +3 +4 +5 +6 +7 +8 + VARIABLE +TMID +DESCRIPTION +Thermal material identification. A unique number or label not +exceeding 8 characters must be specified. +TRO +Thermal density: +EQ.0.0: default to structural density. +Specific heat +Thermal conductance (SI units are W/K) + HC = (heat transfer coefficient) × (beam cross section area) +[W/K] = [W / m^2 K] * [m^2] +HC +TC +Note: +A beam cross section area is not defined on the SECTION_BEAM keyword for an +elform = 6 discrete beam. A beam cross section area is needed for heat transfer +calculations. Therefore, the cross section area is lumped into the value entered for HC. +*MAT_THERMAL_CHEMICAL_REACTION +This is thermal material type 6. The chemical species making up this material undergo +chemical reactions. A maximum of 8 species and 8 chemical reactions can be defined. +The thermal material properties of a finite element undergoing chemical reactions are +calculated based on a mixture law consisting of those chemical species currently present +in the element. The dependence of the chemical reaction rate on temperature is +described by the Arrhenius equation. Time step splitting is used to couple the system +of ordinary differential equations describing the chemical reaction kinetics to the system +of partial differential equations describing the diffusion of heat. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TMID +NCHSP +NCHRX +ICEND +CEND +RBEGIN +GASC +Type +A8 +I +I +I +R +R +R +Chemical Species Cards. Include one card for each of the NCHSP species. These +cards set species properties. The dummy index i is the species number and is equal to 1 +for the first species card, 2 for the second, and so on. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RHOi +LCCPi +LCKi +N0i +MWi +Type +R +I +I +I +I +Reaction Cards. Include one card for each of the NCHSP species. Each field contains +the species’s coefficient for one of the NCHRX chemical reactions. See card format 3 for +explanation of the species index i. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RCi1 +RCi2 +RCi3 +RCi4 +RCi5 +RCi6 +RCi7 +RCi8 +Type +R +R +R +R +R +R +R +Reaction Rate Exponent Cards. Include one card for each of the NCHSP species. +Each field contains the specie’s rate exponent for one of the NCHRX chemical reactions. +See card format 3 for explanation of the species index i. + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RXi1 +RXi2 +RXi3 +RXi4 +RXi5 +RXi6 +RXi7 +RXi8 +Type +R +R +R +R +R +R +R +R +Pre-exponential Factor Card. Each field contains the natural logarithm of its +corresponding reaction’s pre-exponetial factor. + Card 6 +Variable +1 +Z1 +Type +R +2 +Z2 +R +3 +Z3 +R +4 +Z4 +R +5 +Z5 +R +6 +Z6 +R +7 +Z7 +R +8 +Z8 +R +Activation Energy Card. Each field contains the activation energy value for its +corresponding reaction. + Card 7 +Variable +1 +E1 +Type +R +2 +E2 +R +3 +E3 +R +4 +E4 +R +5 +E5 +R +6 +E6 +R +7 +E7 +R +8 +E8 +R +Heat of Reaction Card. Each field contains the heat of reaction value for its +corresponding reaction. + Card 8 +Variable +1 +Q1 +Type +R +2 +Q2 +R +3 +Q3 +R +4 +Q4 +R +5 +Q5 +R +6 +Q6 +R +7 +Q7 +R +8 +Q8 +R + VARIABLE +TMID +3-12 (MAT) +DESCRIPTION +Thermal material identification. A unique number or label not +NCHSP +Number of chemical species (maximum 8) +NCHRX +Number of chemical reactions (maximum 8) +ICEND +Species number controlling reaction termination +RBEGIN +Chemical reaction will start when the sum of the individual +chemical reaction rates are greater than RBEGIN. +GASC +RHOi +LCCPi +LCKi +N0i +MWi +RCij +RXij +Zj +Ej +Qj +Gas constant: 1.987 cal/(g-mole K), 8314. J/(kg-mole K) +Density of the ith species +Load curve ID specifying specific heat vs. temperature for the ith +species. +Load curve ID specifying thermal conductivity vs. temperature +for the ith species +Initial concentration fraction of the ith species +Molecular weight of the ith species. +Reaction coefficient for species i in reaction j. Leave blank for +undefined reactions +Rate exponent for species i in reaction j. Leave blank for +undefined reactions. +Pre-exponential factor for reaction j. Enter the value as ln(Z). +Leave blank for undefined reactions. +Activation energy for reaction j. Leave blank for undefined +reactions. +Heat of reaction for reaction j. Leave blank for undefined +reactions. +Rate Model for a Single Rection: +Chemical reactions are usually expressed in chemical equation notation; for example, a +chemical reaction involving two reactants and two products is +𝑎A + 𝑏B → 𝑔G + ℎH, +(MT6.1) +where A, B, G, and H are chemical species such as NaOH or HCl, and 𝑎, 𝑏, 𝑔, and ℎ are +integers called stoichiometric numbers, indicating the number of molecules involved in a +single reaction. +The rate of reaction is the number of individual reactions per unit time. Using a stoichiometric +identity, which is just an accounting relation, the rate of reaction is proportional to the +rate of change in the concentrations of the species involved in the reaction. For the +chemical reaction in Equation (MT6.1), the relation between concentration and rate, 𝑟, is, +𝑟 = − +d[A] +d𝑡 += − +d[B] +d𝑡 += + +d[G] +d𝑡 += + +d[H] +d𝑡 +, +(MT6.2) +where [X] denotes the concentration of species X, and the sign depends on whether or +not the species is an input, in which case the sign is negative, or a product, in which +case the sign is positive. +The Model +This thermal material model (T06) is built on the assumption that the reaction rate +depends on the concentration of the input species according to +𝑟 = 𝑘(𝑇) ∏[X]𝑝𝑋 + , +where 𝑋 ranges over all species, and, for each species, the exponent, 𝑝X, is determined +by empirical measurement, but may be approximated by the stoichiometric number +associated with 𝑋. The proportionality constant, 𝑘, is related to the cross-section for the +reaction, and it depends on temperature through the Arrhenius equation: +𝑘 = 𝑍(𝑇) exp (− +𝐸𝑖 +𝑅𝑇 +), +where 𝑍(𝑇) is experimentally determined , 𝐸𝑖 is the activation energy , 𝑅 is the gas constant, and 𝑇 is temperature. As an example, for the chemical +reaction of Equation (MT6.1) +𝑟 = 𝑍(𝑇) exp (− +𝐸𝑖 +𝑅𝑇 +) [A]𝛼[B]𝛽, +where the stoichiometric numbers have been used +determined exponents. +instead of experimentally +The rate of heat generation (exothermic) and absorption (endothermic) associated with +a reaction is calculated by multiplying the heat of reaction, 𝑄𝑖 , by its rate. +Rate Model for a System of Reactions: +For a system of coupled chemical reactions, the change in a species’s concentration is +the sum of all the contributions from each individual chemical reaction: +d[X] +d𝑡 += ∑(±)𝑖𝑛(𝑥)𝑖𝑟𝑖 +. +The index i runs over all reactions; 𝑛(𝑥)𝑖 is the stoichiometric number for species X in +reaction 𝑖; and where 𝑟𝑖 is the rate of reaction 𝑖. The sign (±)𝑖 is positive for reactions +that have X as a product and negative for reactions that involve X as an input. +Example: +For the following system of reactions +A → B +A + B → C +2B → C +⇒ +⇒ +⇒ +𝑟1 = 𝑘1[A] +𝑟2 = 𝑘2[A][B] +𝑟3 = 𝑘3[B]2 +(MT6.3) +the time evolution equations are, +d[A] +d𝑡 +d[B] +d𝑡 +d[C] +d𝑡 += ∑ 𝑛(𝑥)𝑖𝑟𝑖 = −𝑘1[A] − 𝑘2[A][B] += ∑ 𝑛(𝑥)𝑖𝑟𝑖 = +𝑘1[A] − 𝑘2[A][B] − 2𝑘3[B]2 +(MT6.4) += ∑ 𝑛(𝑥)𝑖𝑟𝑖 = ++ 𝑘2[A][B] + 𝑘3[B]2. +The coefficients should be identically copied from (MT6.4): +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RC11 +RC12 +RC13 +RC14 +RC15 +RC16 +RC17 +RC18 +Value +-1 +-1 +0 +Variable +RC21 +RC22 +RC23 +RC24 +RC25 +RC26 +RC27 +RC28 +Value ++1 +-1 +-2 +Variable +RC31 +RC32 +RC33 +RC34 +RC35 +RC36 +RC37 +RC38 +Value +0 +1 +1 +The exponents are likewise picked off of (MT6.3) for next set of cards in format 5: +Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RX11 +RX12 +RX13 +RX14 +RX15 +RX16 +RX17 +RX18 +Value ++1 ++1 +0 +Variable +RX21 +RX22 +RX23 +RX24 +RX25 +RX26 +RX27 +RX28 +Value +0 ++1 ++2 +Variable +RX31 +RX32 +RX33 +RX34 +RX35 +RX36 +RX37 +RX38 +Value +0 +0 +0 +Equivalent Units (Normalized Units): +The concentrations are often scaled so that each unit of reactant yields one unit of +product. Systems for which each species is assigned its own unit of concentration based +on stoichiometric considerations are equivalent unit systems. +Being unit-agnostic, LS-DYNA is capable of working in equivalent units. However, +care must be taken so that units are treated consistently, as applying a unit scaling to +the time evolution equations can be nontrivial. +1. For each reaction, the experimentally measured pre-exponential coefficients +carry units that depend on the reaction itself. For instance, the pre-exponential +factors 𝑍1, 𝑍2, and 𝑍3 for the reactions A → B, A + B → C, and 2B → 𝐶 respec- +tively will have units of +[𝑍1] = +[𝑍2] = +[time] +[time] +× +× +[Concentration of A] +[Concentration of A] +× +[Concentration of B] +[𝑍3] = +[time] +× { +[Concentration of B] +} +. +Note that each prefactor has a different dimensionality. +2. The equations in (MT6.2), which relate rate to concentration change, are +logically inconsistent unless all species are measured using the same units for +concentration. A species-dependent system of equivalent units would require +the insertion of additional conversion factors into (MT6.2) thereby changing the +form of the time-evolution equations. +To avoid unit consistency issues, it is recommended +that reactions be defined in the same unit system +that was used to measure their empirical values. +Example of Equivalent Units: +The reaction of Equation (MT6.3), +A → B +A + B → C +2B → C +changes species A into species C through an intermediate which is species B. For each +unit of species C that is produced, the reaction consumes two units of species A. Since +this set of chemical formulae corresponds to the curing of epoxy, which is a nearly +volume-preserving process, it is customary to work in a system of equivalent units that +correspond to species volume fractions. +The following set of equivalent units, then, is used in the published literature: +1. Whatever the starting concentration of species A is, all units are uniformly +rescaled so that [A] = 1 at time zero. Per the boxed remark above, since the +constants were measured with respect to these units, this consideration does +not introduce new complexity. +2. Since the process preserves volume, and since one particle of species C replaces +two particles of species A (and one particle of B replace one of A), the units of +concentration for species C are doubled. +𝐶̃ = 2[C] +Under this transformation the rate relation for C is +𝑟 = ± +d[C] +d𝑡 += +d𝐶̃ +d𝑡 + . +The time evolution Equations (MT6.4) become, (note [C] has been replaced by 𝐶̃) +d[A] +d𝑡 += ∑ 𝑛(𝑥)𝑖𝑟𝑖 = −𝑘1[A] − 𝑘2[A][B] +d[B] +d𝑡 +d𝐶̃ +d𝑡 += ∑ 𝑛(𝑥)𝑖𝑟𝑖 = +𝑘1[A] − 𝑘2[A][B] − 2𝑘3[B]2 += ∑ 𝑛(𝑥)𝑖𝑟𝑖 = ++ 2𝑘2[A][B] + 2𝑘3[B]2. +Whence, +Therefore, since +d[A] +d𝑡 ++ +d[B] +d𝑡 ++ +d𝐶̃ +d𝑡 += 0. +[A] + [B] + 𝐶̃ = 1 +for all values of time, and since concentration values cannot become negative, it is clear +that [A], [B], and 𝐶̃ are volume fractions. +*MAT_T07 +This is thermal material type 7. It is a thermal material with temperature dependent +properties that allows for material creation triggered by temperature. The acronym +CWM stands for Computational Welding Mechanics and the model is intended to be +used for simulating multistage weld processes in combination with the mechanical +counterpart, *MAT_CWM. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TMID +TRO +TGRLC +TGMULT +HDEAD TDEAD +Type +A8 + Card 2 +1 +F +2 +F +3 +F +4 +F +5 +F +6 +7 +8 +Variable +LCHC +LCTC +TLSTART +TLEND +TISTART +TIEND +HGHOST +TGHOST +Type +F +F +F +F +F +F +F +F + VARIABLE +TMID +DESCRIPTION +Thermal material identification. A unique number or label not +exceeding 8 characters must be specified. +TRO +Thermal density: +EQ.0.0: default to structural density. +TGRLC +Thermal generation rate curve number, see *DEFINE_CURVE: +GT.0: function versus time, +EQ.0: use constant multiplier value, TGMULT, +LT.0: function versus temperature. +TGMULT +Thermal generation rate multiplier: +EQ.0.0: no heat generation. +HDEAD +Specific heat for inactive material before birth time +TDEAD +Thermal conductivity for inactive material before birth time +LCHC +*MAT_THERMAL_CWM +DESCRIPTION +Load curve (or table) for specific heat as function of temperature +(and maximum temperature up to current time) +LCTC +Load curve for thermal conductivity as function of temperature +TLSTART +Birth temperature of material start +TLEND +Birth temperature of material end +TISTART +Birth time start +TIEND +Birth time end +HGHOST +Specific heat for ghost (quiet) material +TGHOST +Thermal conductivity for ghost (quiet) material +Remarks: +This material is initially in a quiet state, sometimes referred to as a ghost material. In this +state the material has the thermal properties defined by the quiet specific heat +(HGHOST) and quiet thermal conductivity (TGHOST). These should represent the +void, for example, by picking a relatively small thermal conductivity. +However, the ghost specific heat must be chosen with care, since the temperature must +be allowed to increase at a reasonable rate due to the heat from the weld source. When +the temperature reaches the birth temperature, a history variable representing the +indicator of the welding material is incremented. This variable follows +𝛾(𝑡) = min [1, max (0, +𝑇max − 𝑇𝑙 +end − 𝑇𝑙 +𝑇𝑙 +start +start +)] +where 𝑇max = max{𝑇(𝑠)|𝑠 < 𝑡}. +The effective thermal material properties are interpolated as +quiet(1 − 𝛾) +𝑐 ̃𝑝 = 𝑐𝑝(𝑇, 𝑇max)𝛾 + 𝑐𝑝 +𝜇̃ = 𝜇(𝑇)𝛾 + 𝜇quiet(1 − 𝛾) +where 𝑐𝑝 and 𝜇 are the specific heat and thermal conductivity, respectively. Here, the +specific heat, 𝑐𝑝, is either a temperature dependent curve, or a collection of temperature +dependent curves, ordered in a table according to maximum temperature 𝑇𝑚𝑎𝑥. +The time parameters for creating the material provide additional formulae for the final +values of the thermal properties. Before the birth time 𝑡𝑖 +start of the material has been +reached, the specific heat 𝑐𝑝 +dead and thermal conductivity 𝜇dead are used. The default +values, i.e. the values used if no user input is given, are +dead = 1010𝑐𝑝(𝑇, 𝑇max) +𝑐𝑝 +𝜇dead = 0 +Thus, the final values of the thermal properties read +𝑐𝑝 = +𝜇 = +⎧ +{{{{{{ +{{{{{{ +⎨ +⎩ +dead +𝑐𝑝 +start +𝑡 − 𝑡𝑖 +end − 𝑡𝑖 +𝑡𝑖 +start +dead ++ 𝑐𝑝 +end +𝑡 − 𝑡𝑖 +start − 𝑡𝑖 +𝑡𝑖 +end +𝑐 ̃𝑝 +𝑐 ̃𝑝 +𝜇dead +start +𝑡 − 𝑡𝑖 +end − 𝑡𝑖 +𝑡𝑖 +start ++ 𝜇dead +end +𝑡 − 𝑡𝑖 +start − 𝑡𝑖 +𝑡𝑖 +end +𝜇̃ +𝜇̃ +⎧ +{{{{{{ +{{{{{{ +⎨ +⎩ +start +𝑡 ≤ 𝑡𝑖 +start < 𝑡 ≤ 𝑡𝑖 +𝑡𝑖 +end +end < 𝑡 +𝑡𝑖 +start +𝑡 ≤ 𝑡𝑖 +start < 𝑡 ≤ 𝑡𝑖 +𝑡𝑖 +end +. +end < 𝑡 +𝑡𝑖 +These parameters allow the user to control when the welding layor becomes active and +thereby define a multistage welding process. Prior to the birth time, the temperature is +kept more or less constant due to the large specific heat, and, thus, the material is +prevented from being created +*MAT_THERMAL_ORTHOTROPIC_TD_LC +This is thermal material type 8. It allows temperature dependent orthotropic properties +to be defined by load curves. The temperature dependency is defined by specifying a +minimum of two data points. The properties must be defined for the temperature range +that the material will see in the analysis. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TMID +TRO +TGRLC +TGMULT +AOPT +TLAT +HLAT +F +5 +5 +A2 +F +5 +F +6 +6 +A3 +F +6 +F +7 +8 +7 +8 +7 +8 +Type +A8 + Card 2 +1 +F +2 +F +3 +F +4 +Variable +LCC +LCK1 +LCK2 +LCK3 +Type +I +I +I +I +4 +A1 +F +4 +2 +YP +F +2 +D2 +F +3 +ZP +F +3 +D3 +F + Card 3 +Variable +1 +XP +Type +F + Card 4 +Variable +1 +D1 +Type +F + VARIABLE +TMID +DESCRIPTION +Thermal material identification. A unique number or label not +exceeding 8 characters must be specified. +VARIABLE +DESCRIPTION +TRO +Thermal density: +EQ.0.0: default to structural density. +TGRLC +Thermal generation rate curve number, see *DEFINE_CURVE: +GT.0: function versus time, +EQ.0: use constant multiplier value, TGMULT, +LT.0: function versus temperature. +TGMULT +Thermal generation rate multiplier: +EQ.0.0: no heat generation. +AOPT +Material axes definition: : +EQ.0.0: locally orthotropic with material axes by element +nodes N1, N2 and N4, +EQ.1.0: locally orthotropic with material axes determined by a +point in space and global location of element center, +EQ.2.0: globally orthotropic with material axes determined by +TLAT +HLAT +LCC +LCK1 +LCK2 +LCK3 +vectors. +Phase change temperature +Latent heat +Load Curve Specific Heat +Load Curve Thermal Conductivity K1 in local x-direction +Load Curve Thermal Conductivity K2 in local y-direction +Load Curve Thermal Conductivity K3 in local z-direction +XP, YP, ZP +Define coordinate of point p for AOPT = 1 +A1, A2, A3 +Define components of vector a for AOPT = 2 +D1, D2, D3 +Define components of vector d for AOPT = 2 +*MAT_THERMAL_ORTHOTROPIC_TD_LC +See *MAT_THERMAL_ORTHOTROPIC keyword for a description of the orthotropic +axis options, AOPT. +*MAT_THERMAL_ISOTROPIC_PHASE_CHANGE +This is thermal material type 9. It allows temperature dependent isotropic properties +with phase change to be defined. The latent heat of the material is defined together +with the solid and liquid temperatures. The temperature dependency is defined by +specifying a minimum of two and a maximum of eight data points. The properties +must be defined for the temperature range that the material will see in the analysis. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TMID +TRO +TGRLC +TGMULT +Type +A8 +F +F +F + Card 2 +Variable +1 +T1 +Type +F + Card 3 +Variable +1 +C1 +Type +F + Card 4 +Variable +1 +K1 +Type +F +2 +T2 +F +2 +C2 +F +2 +K2 +F +3 +T3 +F +3 +C3 +F +3 +K3 +F +4 +T4 +F +4 +C4 +F +4 +K4 +F +5 +T5 +F +5 +C5 +F +5 +K5 +F +6 +T6 +F +6 +C6 +F +6 +K6 +F +7 +T7 +F +7 +C7 +F +7 +K7 +F +8 +T8 +F +8 +C8 +F +8 +K8 +Card 5 +1 +2 +Variable +SOLT +LIQT +Type +F +F +3 +LH +F +4 +5 +6 +7 +8 + VARIABLE +TMID +DESCRIPTION +Thermal material identification. A unique number or label not +exceeding 8 characters must be specified. +TRO +Thermal density: +EQ.0.0: default to structural density. +TGRLC +Thermal generation rate curve number, see *DEFINE_CURVE: +GT.0: function versus time, +EQ.0: use constant multiplier value, TGMULT, +LT.0: function versus temperature. +TGMULT +Thermal generation rate multiplier: +EQ.0.0: no heat generation. +T1, …, T8 +Temperatures (T1, …, T8) +C1, …, C8 +Specific heat at T1, …, T8 +K1, …, K8 +Thermal conductivity at T1, …, T8 +Solid temperature, TS (must be < TL) +Liquid temperature, TL (must be > TS) +Latent heat +SOLT +LIQT +LH +Remarks: +During phase change, that is between the solid and liquid temperatures, the specific +heat of the material will be enhanced to account for the latent heat as follows: +𝑐(𝑡) = 𝑚 [1 − cos2𝜋 ( +𝑇 − 𝑇𝑆 +𝑇𝐿 − 𝑇𝑆 +)] , +𝑇𝑆 < 𝑇 < 𝑇𝐿 +where +𝑇𝐿 = liquid temperature +𝑇𝑆 = solid temperature +𝑇 = temperature +𝑚 = multiplier such that 𝜆 = ∫ 𝐶(𝑇)𝑑𝑇 +𝑇𝐿 +𝑇𝑆 +𝜆 = latent heat +𝑐 = specific heat +*MAT_THERMAL_ISOTROPIC_TD_LC +This is thermal material type 10. It allows isotropic thermal properties that are +temperature dependent specified by load curves to be defined. The properties must be +defined for the temperature range that the material will see in the analysis. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TMID +TRO +TGRLC +TGMULT +Type +A8 + Card 2 +1 +F +2 +F +3 +F +4 +Variable +HCLC +TCLC +Type +F +F +5 +6 +7 +8 + VARIABLE +TMID +DESCRIPTION +Thermal material identification. A unique number or label not +exceeding 8 characters must be specified. +TRO +Thermal density: +EQ.0.0: default to structural density. +TGRLC +Thermal generation rate curve number, see *DEFINE_CURVE: +GT.0: function versus time, +EQ.0: use constant multiplier value, TGMULT, +LT.0: function versus temperature. +TGMULT +Thermal generation rate multiplier: +EQ.0.0: no heat generation. +HCLC +TCLC +Load curve ID specifying specific heat vs. temperature. +Load curve ID specifying thermal conductivity vs. temperature. +*MAT_THERMAL_USER_DEFINED +These are Thermal Material Types 11 - 15. The user can supply his own subroutines. +Please consult Appendix H for more information. + Card 1 +1 +Variable +MID +2 +RO +3 +MT +4 +5 +6 +7 +8 +LMC +NVH +AOPT +IORTHO +IHVE +Type +A8 +F +F +F +F +F +F +F +Orthotropic Card 1. Additional card read in when IORTHO = 1. + Card 2 +Variable +1 +XP +Type +F +2 +YP +F +3 +ZP +F +4 +A1 +F +5 +A2 +F +6 +A3 +F +7 +8 +Orthotropic Card 2. Additional card read in when IORTHO = 1. + Card 3 +Variable +1 +D1 +Type +F +2 +D2 +F +3 +D3 +F +4 +5 +6 +7 +8 +Material Parameter Cards. Set up to 8 parameters per card. Include up to 4 cards. +This input ends at the next keyword (“*”) card. + Card 4 +Variable +1 +P1 +Type +F +2 +P2 +F +3 +P3 +F +4 +P4 +F +5 +P5 +F +6 +P6 +F +7 +P7 +F +8 +P8 +F + VARIABLE +MID +LS-DYNA R10.0 +DESCRIPTION +Material identification. A unique number or label not exceeding 8 +VARIABLE +DESCRIPTION +RO +MT +LMC +NVH +AOPT +Thermal mass density. +User material type (11-15 inclusive). +Length of material constants array. LMC must not be greater +than 32. +Number of history variables. +Material axes option of orthotropic materials. +IORTHO = 1.0. + Use +if +EQ.0.0: locally orthotropic with material axes by element nodes +N1, N2 and N4, +EQ.1.0: locally orthotropic with material axes determined by a +point in space and global location of element center, +EQ.2.0: globally orthotropic with material axes determined by +vectors. +LT.0.0: the absolute value of AOPT is a coordinate system ID +number (CID on *DEFINE_COORDINATE_NODES, +*DEFINE_COORDINATE_SYSTEM or *DEFINE_CO- +ORDINATE_VECTOR). Available in R3 version of 971 +and later. +IORTHO +Set to 1.0 if the material is orthotropic. +IHVE +XP - D3 +P1 +⋮ +Set to 1.0 to activate exchange of history variables between +mechanical and thermal user material models. +Material axes orientation of orthotropic materials. +IORTHO = 1.0 + Use if +First material parameter. +⋮ +PLMC +LMCth material parameter. +Remarks: +1. The IHVE = 1 option makes it possible for a thermal user material subroutine to +read the history variables of a mechanical user material subroutine defined for +the same part and vice versa. If the integration points for the thermal and me- +chanical elements are not coincident then extrapolation/interpolation is used to +calculate the value when reading history variables. +2. Option TITLE is supported +3. +*INCLUDE_TRANSFORM: Transformation of units is only supported for RO +field and vectors on card 2 and 3. + +Corporate Address +Livermore Software Technology Corporation +P. O. Box 712 +Livermore, California 94551-0712 +Support Addresses +Technology +Software +Livermore +Corporation +7374 Las Positas Road +Livermore, California 94551 +Tel: 925-449-2500 Fax: 925-449-2507 +Email: sales@lstc.com +Website: www.lstc.com +Technology +Software +Livermore +Corporation +1740 West Big Beaver Road +Suite 100 +Troy, Michigan 48084 +Tel: 248-649-4728 Fax: 248-649-6328 +Disclaimer +Copyright © 1992-2017 Livermore Software Technology Corporation. All Rights +Reserved. +LS-DYNA®, LS-OPT® and LS-PrePost® are registered trademarks of Livermore Software +Technology Corporation in the United States. All other trademarks, product names and +brand names belong to their respective owners. +LSTC reserves the right to modify the material contained within this manual without +prior notice. +The information and examples included herein are for illustrative purposes only and +are not intended to be exhaustive or all-inclusive. LSTC assumes no liability or +responsibility whatsoever for any direct or indirect damages or inaccuracies of any type +or nature that could be deemed to have resulted from the use of this manual. +Any reproduction, in whole or in part, of this manual is prohibited without the prior +Patents +LSTC products are protected under the following patents: +US Patents: 7167816, 7286972, 7308387, 7382367, 7386425, 7386428, 7392163, 7395128, +7415400, 7428713, 7472602, 7499050, 7516053, 7533577, 7590514, 7613585, 7640146, +7657394, 7660480, 7664623, 7702490, 7702494, 7945432, 7953578, 7987143, 7996344, +8050897, 8069017, 8126684, 8150668, 8165856, 8180605, 8190408, 8200458, 8200464, +8209157, 8271237, 8296109, 8306793, 8374833, 8423327, 8467997, 8489372, 8494819, +8515714, 8521484, 8577656, 8612186, 8666719, 8744825, 8768660, 8798973, 8898042, +9020784, 9098657, 9117042, 9135377, 9286422, 9292632, 9405868, 9430594, 9507892, +9607115. +Japan Patents: 5090426, 5281057, 5330300, 5373689, 5404516, 5411013, 5411057, 5431133, +5520553, 5530552, 5589198, 5601961, 5775708, 5792995, 5823170, 6043146, 6043198. +Patents: +China +ZL200910246429.8, +ZL201010171603.X, +ZL201010533046.1, +ZL201110140142.4, +ZL201210514668.9, +ZL201210475617.X, ZL201310081855.7. +ZL200910207380.5, +ZL201010128222.3, +ZL201010174074.9, +ZL201110035253.9, +ZL201210039535.0, +ZL201210422902.5, +ZL200910165817.3, +ZL201010132510.6, +ZL201010287263.7, +ZL201110065789.5, +ZL201210286459.3, +ZL201210424131.3, +ZL200910221325.1, +ZL201010155066.X, +ZL201110037461.2, +ZL201110132394.2, +ZL201210275406.1, +ZL201310021716.5, +AES +AES. Copyright © 2001, Dr Brian Gladman < brg@gladman.uk.net>, Worcester, UK. +All rights reserved. +LICENSE TERMS +The free distribution and use of this software in both source and binary form is allowed +(with or without changes) provided that: +1. distributions of this source code include the above copyright notice, this list of +conditions and the following disclaimer; +2. distributions in binary form include the above copyright notice, this list of +conditions and the following disclaimer in the documentation and/or other +associated materials; +3. +the copyright holder's name is not used to endorse products built using this +software without specific written permission. +DISCLAIMER +This software is provided 'as is' with no explicit or implied warranties in respect of any +properties, including, but not limited to, correctness and fitness for purpose. +Issue Date: 21/01/2002 +INTRODUCTION +INTRODUCTION +CHRONOLOGICAL HISTORY +DYNA3D originated at the Lawrence Livermore National Laboratory [Hallquist 1976]. +The early applications were primarily for the stress analysis of structures subjected to a +variety of impact loading. These applications required what was then significant +computer resources, and the need for a much faster version was immediately obvious. +Part of the speed problem was related to the inefficient implementation of the element +technology which was further aggravated by the fact that supercomputers in 1976 were +much slower than today’s PC. Furthermore, the primitive sliding interface treatment +could only treat logically regular interfaces that are uncommon in most finite element +discretizations of complicated three-dimensional geometries; consequently, defining a +suitable mesh for handling contact was often very difficult. The first version contained +trusses, membranes, and a choice of solid elements. The solid elements ranged from a +one-point quadrature eight-noded element with hourglass control to a twenty-noded +element with eight integration points. Due to the high cost of the twenty node solid, the +zero energy modes related to the reduced 8-point integration, and the high frequency +content which drove the time step size down, higher order elements were all but +abandoned in later versions of DYNA3D. A two-dimensional version, DYNA2D, was +developed concurrently. +A new version of DYNA3D was released in 1979 that was programmed to provide near +optimal speed on the CRAY-1 supercomputers, contained an improved sliding interface +treatment that permitted triangular segments and was an order of magnitude faster +than the previous contact treatment. The 1979 version eliminated structural and higher +order solid elements and some of the material models of the first version. This version +also included an optional element-wise implementation of the integral difference +method developed by Wilkins et al. [1974]. +The 1981 version [Hallquist 1981a] evolved from the 1979 version. Nine additional +material models were added to allow a much broader range of problems to be modeled +including explosive-structure and soil-structure interactions. Body force loads were +implemented for angular velocities and base accelerations. A link was also established +from the 3D Eulerian code, JOY [Couch, et. al., 1983] for studying the structural +response to impacts by penetrating projectiles. An option was provided for storing +element data on disk thereby doubling the capacity of DYNA3D. +The 1982 version of DYNA3D [Hallquist 1982] accepted DYNA2D [Hallquist 1980] +material input directly. The new organization was such that equations of state and +constitutive models of any complexity could be easily added. Complete vectorization +INTRODUCTION +of the material models had been nearly achieved with about a 10 percent increase in +execution speed over the 1981 version. +In the 1986 version of DYNA3D [Hallquist and Benson 1986], many new features were +added, including beams, shells, rigid bodies, single surface contact, interface friction, +discrete springs and dampers, optional hourglass treatments, optional exact volume +integration, and VAX/ VMS, IBM, UNIX, COS operating systems compatibility, that +greatly expanded its range of applications. DYNA3D thus became the first code to have +a general single surface contact algorithm. +In the 1987 version of DYNA3D [Hallquist and Benson 1987] metal forming simulations +and composite analysis became a reality. This version included shell thickness changes, +the Belytschko-Tsay shell element [Belytschko and Tsay, 1981], and dynamic relaxation. +Also included were non-reflecting boundaries, user specified integration rules for shell +and beam elements, a layered composite damage model, and single point constraints. +New capabilities added in the 1988 DYNA3D [Hallquist 1988] version included a cost +effective resultant beam element, a truss element, a C0 triangular shell, the BCIZ +triangular shell [Bazeley et al. 1965], mixing of element formulations in calculations, +composite failure modeling for solids, noniterative plane stress plasticity, contact +surfaces with spot welds, tie break sliding surfaces, beam surface contact, finite +stonewalls, stonewall reaction forces, energy calculations for all elements, a crushable +foam constitutive model, comment cards in the input, and one-dimensional slidelines. +By the end of 1988 it was obvious that a much more concentrated effort would be +required in the development of this software if problems in crashworthiness were to be +properly solved; therefore, Livermore Software Technology Corporation was founded +to continue the development of DYNA3D as a commercial version called LS-DYNA3D +which was later shortened to LS-DYNA. The 1989 release introduced many enhanced +capabilities including a one-way treatment of slide surfaces with voids and friction; +cross-sectional forces for structural elements; an optional user specified minimum time +step size for shell elements using elastic and elastoplastic material models; nodal +accelerations in the time history database; a compressible Mooney-Rivlin material +model; a closed-form update shell plasticity model; a general rubber material model; +unique penalty specifications for each slide surface; external work tracking; optional +time step criterion for 4-node shell elements; and internal element sorting to allow full +vectorization of right-hand-side force assembly. +During the last ten years, considerable progress has been made as may be seen in the +chronology of the developments which follows. +Capabilities added in 1989-1990: +• arbitrary node and element numbers, +INTRODUCTION +• fabric model for seat belts and airbags, +• composite glass model, +• vectorized type 3 contact and single surface contact, +• many more I/O options, +• all shell materials available for 8 node thick shell, +• strain rate dependent plasticity for beams, +• fully vectorized iterative plasticity, +• interactive graphics on some computers, +• nodal damping, +• shell thickness taken into account in shell type 3 contact, +• shell thinning accounted for in type 3 and type 4 contact, +• soft stonewalls, +• print suppression option for node and element data, +• massless truss elements, rivets – based on equations of rigid body dynamics, +• massless beam elements, spot welds – based on equations of rigid body dynam- +ics, +• expanded databases with more history variables and integration points, +• force limited resultant beam, +• rotational spring and dampers, local coordinate systems for discrete elements, +• resultant plasticity for C0 triangular element, +• energy dissipation calculations for stonewalls, +• hourglass energy calculations for solid and shell elements, +• viscous and Coulomb friction with arbitrary variation over surface, +• distributed loads on beam elements, +• Cowper and Symonds strain rate model, +• segmented stonewalls, +• stonewall Coulomb friction, +• stonewall energy dissipation, +• airbags (1990), +• nodal rigid bodies, +• automatic sorting of triangular shells into C0 groups, +• mass scaling for quasi static analyses, +INTRODUCTION +• user defined subroutines, +• warpage checks on shell elements, +• thickness consideration in all contact types, +• automatic orientation of contact segments, +• sliding interface energy dissipation calculations, +• nodal force and energy database for applied boundary conditions, +• defined stonewall velocity with input energy calculations, +Capabilities added in 1991-1992: +• rigid/deformable material switching, +• rigid bodies impacting rigid walls, +• strain-rate effects in metallic honeycomb model 26, +• shells and beams interfaces included for subsequent component analyses, +• external work computed for prescribed displacement/velocity/accelerations, +• linear constraint equations, +• MPGS database, +• MOVIE database, +• Slideline interface file, +• automated contact input for all input types, +• automatic single surface contact without element orientation, +• constraint technique for contact, +• cut planes for resultant forces, +• crushable cellular foams, +• urethane foam model with hysteresis, +• subcycling, +• friction in the contact entities, +• strains computed and written for the 8 node thick shells, +• “good” 4 node tetrahedron solid element with nodal rotations, +• 8 node solid element with nodal rotations, +• 2 × 2 integration for the membrane element, +• Belytschko-Schwer integrated beam, +• thin-walled Belytschko-Schwer integrated beam, +INTRODUCTION +• improved TAURUS database control, +• null material for beams to display springs and seatbelts in TAURUS, +• parallel implementation on Crays and SGI computers, +• coupling to rigid body codes, +• seat belt capability. +Capabilities added in 1993-1994: +• Arbitrary Lagrangian Eulerian brick elements, +• Belytschko-Wong-Chiang quadrilateral shell element, +• Warping stiffness in the Belytschko-Tsay shell element, +• Fast Hughes-Liu shell element, +• Fully integrated thick shell element, +• Discrete 3D beam element, +• Generalized dampers, +• Cable modeling, +• Airbag reference geometry, +• Multiple jet model, +• Generalized joint stiffnesses, +• Enhanced rigid body to rigid body contact, +• Orthotropic rigid walls, +• Time zero mass scaling, +• Coupling with USA (Underwater Shock Analysis), +• Layered spot welds with failure based on resultants or plastic strain, +• Fillet welds with failure, +• Butt welds with failure, +• Automatic eroding contact, +• Edge-to-edge contact, +• Automatic mesh generation with contact entities, +• Drawbead modeling, +• Shells constrained inside brick elements, +• NIKE3D coupling for springback, +• Barlat’s anisotropic plasticity, +INTRODUCTION +• Superplastic forming option, +• Rigid body stoppers, +• Keyword input, +• Adaptivity, +• First MPP (Massively Parallel) version with limited capabilities. +• Built in least squares fit for rubber model constitutive constants, +• Large hysteresis in hyperelastic foam, +• Bilhku/Dubois foam model, +• Generalized rubber model, +Capabilities added in 1995: +• Belytschko - Leviathan Shell +• Automatic switching between rigid and deformable bodies. +• Accuracy on SMP machines to give identical answers on one, two or more +processors. +• Local coordinate systems for cross-section output can be specified. +• Null material for shell elements. +• Global body force loads now may be applied to a subset of materials. +• User defined loading subroutine. +• Improved interactive graphics. +• New initial velocity options for specifying rotational velocities. +• Geometry changes after dynamic relaxation can be considered for initial +velocities.. +• Velocities may also be specified by using material or part ID’s. +• Improved speed of brick element hourglass force and energy calculations. +• Pressure outflow boundary conditions have been added for the ALE options. +• More user control for hourglass control constants for shell elements. +• Full vectorization in constitutive models for foam, models 57 and 63. +• Damage mechanics plasticity model, material 81, +• General linear viscoelasticity with 6 term prony series. +• Least squares fit for viscoelastic material constants. +• Table definitions for strain rate effects in material type 24. +INTRODUCTION +• Improved treatment of free flying nodes after element failure. +• Automatic projection of nodes in CONTACT_TIED to eliminate gaps in the +surface. +• More user control over contact defaults. +• Improved interpenetration warnings printed in automatic contact. +• Flag for using actual shell thickness in single surface contact logic rather than the +default. +• Definition by exempted part ID’s. +• Airbag to Airbag venting/segmented airbags are now supported. +• Airbag reference geometry speed improvements by using the reference geometry +for the time step size calculation. +• Isotropic airbag material may now be directly for cost efficiency. +• Airbag fabric material damping is specified as the ratio of critical damping. +• Ability to attach jets to the structure so the airbag, jets, and structure to move +together. +• PVM 5.1 Madymo coupling is available. +• Meshes are generated within LS-DYNA3D for all standard contact entities. +• Joint damping for translational motion. +• Angular displacements, rates of displacements, damping forces, etc. in JNT- +FORC file. +• Link between LS-NIKE3D to LS-DYNA3D via *INITIAL_STRESS keywords. +• Trim curves for metal forming springback. +• Sparse equation solver for springback. +• Improved mesh generation for IGES and VDA provides a mesh that can directly +be used to model tooling in metal stamping analyses. +• Capabilities added in 1996-1997 in Version 940: +• Part/Material ID’s may be specified with 8 digits. +• Rigid body motion can be prescribed in a local system fixed to the rigid body. +• Nonlinear least squares fit available for the Ogden rubber model. +• Least squares fit to the relaxation curves for the viscoelasticity in rubber. +• Fu-Chang rate sensitive foam. +• 6 term Prony series expansion for rate effects in model 57-now 73 +• Viscoelastic material model 76 implemented for shell elements. +• Mechanical threshold stress (MTS) plasticity model for rate effects. +INTRODUCTION +• Thermoelastic-plastic material model for Hughes-Liu beam element. +• Ramberg-Osgood soil model +• Invariant local coordinate systems for shell elements are optional. +• Second order accurate stress updates. +• Four noded, linear, tetrahedron element. +• Co-rotational solid element for foam that can invert without stability problems. +• Improved speed in rigid body to rigid body contacts. +• Improved searching for the a_3, a_5 and a10 contact types. +• Invariant results on shared memory parallel machines with the a_n contact +types. +• Thickness offsets in type 8 and 9 tie break contact algorithms. +• Bucket sort frequency can be controlled by a load curve for airbag applications. +• In automatic contact each part ID in the definition may have unique: +◦ Static coefficient of friction +◦ Dynamic coefficient of friction +◦ Exponential decay coefficient +◦ Viscous friction coefficient +◦ Optional contact thickness +◦ Optional thickness scale factor +◦ Local penalty scale factor +• Automatic beam-to-beam, shell edge-to-beam, shell edge-to-shell edge and +single surface contact algorithm. +• Release criteria may be a multiple of the shell thickness in types a_3, a_5, a10, 13, +and 26 contact. +• Force transducers to obtain reaction forces in automatic contact definitions. +Defined manually via segments, or automatically via part ID’s. +• Searching depth can be defined as a function of time. +• Bucket sort frequency can be defined as a function of time. +• Interior contact for solid (foam) elements to prevent “negative volumes.” +• Locking joint +• Temperature dependent heat capacity added to Wang-Nefske inflator models. +• Wang Hybrid inflator model [Wang, 1996] with jetting options and bag-to-bag +venting. +• Aspiration included in Wang’s hybrid model [Nusholtz, Wang, Wylie, 1996]. +INTRODUCTION +• Extended Wang’s hybrid inflator with a quadratic temperature variation for heat +capacities [Nusholtz, 1996]. +• Fabric porosity added as part of the airbag constitutive model. +• Blockage of vent holes and fabric in contact with structure or itself considered in +venting with leakage of gas. +• Option to delay airbag liner with using the reference geometry until the +reference area is reached. +• Birth time for the reference geometry. +• Multi-material Euler/ALE fluids, +◦ 2nd order accurate formulations. +◦ Automatic coupling to shell, brick, or beam elements +◦ Coupling using LS-DYNA contact options. +◦ Element with fluid + void and void material +◦ Element with multi-materials and pressure equilibrium +• Nodal inertia tensors. +• 2D plane stress, plane strain, rigid, and axisymmetric elements +• 2D plane strain shell element +• 2D axisymmetric shell element. +• Full contact support in 2D, tied, sliding only, penalty and constraint techniques. +• Most material types supported for 2D elements. +• Interactive remeshing and graphics options available for 2D. +• Subsystem definitions for energy and momentum output. +• Boundary element method for incompressible fluid dynamics and fluid-structure +interaction problems. +Capabilities added during 1997-1998 in Version 950: +• Adaptive refinement can be based on tooling curvature with FORMING contact. +• The display of drawbeads is now possible since the drawbead data is output into +the D3PLOT database. +• An adaptive box option, *DEFINE_BOX_ADAPTIVE, allows control over the +refinement level and location of elements to be adapted. +• A root identification file, ADAPT.RID, gives the parent element ID for adapted +elements. +• Draw bead box option, *DEFINE_BOX_DRAWBEAD, simplifies drawbead +input. +INTRODUCTION +• The new control option, CONTROL_IMPLICIT, activates an implicit solution +scheme. +• 2D Arbitrary-Lagrangian-Eulerian elements are available. +• 2D automatic contact is defined by listing part ID's. +• 2D r-adaptivity for plane strain and axisymmetric forging simulations is +available. +• 2D automatic non-interactive rezoning as in LS-DYNA2D. +• 2D plane strain and axisymmetric element with 2x2 selective-reduced integration +are implemented. +• Implicit 2D solid and plane strain elements are available. +• Implicit 2D contact is available. +• The new keyword, *DELETE_CONTACT_2DAUTO, allows the deletion of 2D +automatic contact definitions. +• The keyword, *LOAD_BEAM is added for pressure boundary conditions on 2D +elements. +• A viscoplastic strain rate option is available for materials: +◦ *MAT_PLASTIC_KINEMATIC +◦ *MAT_JOHNSON_COOK +◦ *MAT_POWER_LAW_PLASTICITY +◦ *MAT_STRAIN_RATE_DEPENDENT_PLASTICITY +◦ *MAT_PIECEWISE_LINEAR_PLASTICITY +◦ *MAT_RATE_SENSITIVE_POWERLAW_PLASTICITY +◦ *MAT_ZERILLI-ARMSTRONG +◦ *MAT_PLASTICITY_WITH_DAMAGE +◦ *MAT_PLASTICITY_COMPRESSION_TENSION +• Material model, *MAT_Plasticity_with_DAMAGE, has a piecewise +linear +damage curve given by a load curve ID. +• The Arruda-Boyce hyper-viscoelastic rubber model is available, see *MAT_AR- +RUDA_BOYCE. +• Transverse-anisotropic-viscoelastic material +for heart +tissue, see *MAT_- +HEART_TISSUE. +• Lung hyper-viscoelastic material, see *MAT_LUNG_TISSUE. +• Compression/tension plasticity model, see *MAT_Plasticity_COMPRESSION_- +TENSION. +• The Lund strain rate model, *MAT_STEINBERG_LUND, is added to Steinberg- +Guinan plasticity model. +INTRODUCTION +• Rate sensitive foam model, *MAT_FU_CHANG_FOAM, has been extended to +include engineering strain rates, etc. +• Model, *MAT_MODIFIED_Piecewise_Linear_Plasticity, is added for modeling +the failure of aluminum. +• Material model, *MAT_SPECIAL_ORTHOTROPIC, added for television shadow +mask problems. +• Erosion strain is implemented for material type, *MAT_bamman_damage. +• The equation of state, *EOS_JWLB, is available for modeling the expansion of +explosive gases. +• The reference geometry option is extended for foam and rubber materials and +can be used for stress initialization, see *INITIAL_FOAM_REFERENCE_GEOM- +ETRY. +• A vehicle positioning option is available for setting the initial orientation and +velocities, see *INITIAL_VEHICLE_KINEMATICS. +• A boundary element method is available for incompressible fluid dynamics +problems. +• The thermal materials work with instantaneous coefficients of thermal expan- +sion: +◦ *MAT_ELASTIC_PLASTIC_THERMAL +◦ *MAT_ORTHOTROPIC_THERMAL +◦ *MAT_TEMPERATURE_DEPENDENT_ORTHOTROPIC +◦ *MAT_ELASTIC_WITH_VISCOSITY +• Airbag interaction flow rate versus pressure differences. +• Contact segment search option, [bricks first optional] +• A through thickness Gauss integration rule with 1-10 points is available for shell +elements. Previously, 5 were available. +• Shell element formulations can be changed in a full deck restart. +• The tied interface which is based on constraint equations, TIED_SURFACE_TO_- +SURFACE, can now fail if_FAILURE, is appended. +• A general failure criteria for solid elements is independent of the material type, +see *MAT_ADD_EROSION +• Load curve control can be based on thinning and a flow limit diagram, see *DE- +FINE_CURVE_FEEDBACK. +• An option to filter the spotweld resultant forces prior to checking for failure has +been added the the option, *CONSTRAINED_SPOTWELD, by appending FIL- +TERED_FORCE, to the keyword. +INTRODUCTION +• Bulk viscosity is available for shell types 1, 2, 10, and 16. +• When defining the local coordinate system for the rigid body inertia tensor a +local coordinate system ID can be used. This simplifies dummy positioning. +• Prescribing displacements, velocities, and accelerations is now possible for rigid +body nodes. +• One way flow is optional for segmented airbag interactions. +• Pressure time history input for airbag type, LINEAR_FLUID, can be used. +• An option is available to independently scale system damping by part ID in each +of the global directions. +• An option is available to independently scale global system damping in each of +the global directions. +• Added option to constrain global DOF along lines parallel with the global axes. +The keyword is *CONSTRAINED_GLOBAL. This option is useful for adaptive +remeshing. +• Beam end code releases are available, see *ELEMENT_BEAM. +• An initial force can be directly defined for the cable material, *MAT_CABLE_- +DISCRETE_BEAM. The specification of slack is not required if this option is +used. +• Airbag pop pressure can be activated by accelerometers. +• Termination may now be controlled by contact, via *TERMINATION_CON- +TACT. +• Modified shell elements types 8, 10 and the warping stiffness option in the +Belytschko-Tsay shell to ensure orthogonality with rigid body motions in the +event that the shell is badly warped. This is optional in the Belytschko-Tsay shell +and the type 10 shell. +• A one point quadrature brick element with an exact hourglass stiffness matrix +has been implemented for implicit and explicit calculations. +• Automatic file length determination for D3PLOT binary database is now +implemented. This insures that at least a single state is contained in each +D3PLOT file and eliminates the problem with the states being split between files. +• The dump files, which can be very large, can be placed in another directory by +specifying +on the execution line. +d=/home/user /test/d3dump +• A print flag controls the output of data into the MATSUM and RBDOUT files by +part ID's. The option, PRINT, has been added as an option to the *PART key- +word. +INTRODUCTION +• Flag has been added to delete material data from the D3THDT file. See *DATA- +BASE_EXTENT_BINARY and column 25 of the 19th control card in the struc- +tured input. +• After dynamic relaxation completes, a file is written giving the displaced state +which can be used for stress initialization in later runs. +Capabilities added during 1998-2000 in Version 960: +Most new capabilities work on both the MPP and SMP versions; however, the +capabilities that are implemented for the SMP version only, which were not considered +critical for this release, are flagged below. These SMP unique capabilities are being +extended for MPP calculations and will be available in the near future. The implicit +capabilities for MPP require the development of a scalable eigenvalue solver, which is +under development for a later release of LS-DYNA. +• Incompressible flow solver is available. Structural coupling is not yet imple- +mented. +• Adaptive mesh coarsening can be done before the implicit springback calculation +in metal forming applications. +• Two-dimensional adaptivity can be activated in both implicit and explicit +calculations. (SMP version only) +• An internally generated smooth load curve for metal forming tool motion can be +activated with the keyword: *DEFINE_CURVE_SMOOTH. +• Torsional forces can be carried through the deformable spot welds by using the +contact type: *CONTACT_SPOTWELD_WITH_TORSION (SMP version only +with a high priority for the MPP version if this option proves to be stable.) +• Tie break automatic contact is now available via the *CONTACT_AUTOMAT- +IC_…_TIEBREAK options. This option can be used for glued panels. (SMP +only) +• *CONTACT_RIGID_SURFACE option is now available for modeling road +surfaces (SMP version only). +• Fixed rigid walls PLANAR and PLANAR_FINITE are represented in the binary +output file by a single shell element. +• Interference fits can be modeled with the INTERFERENCE option in contact. +• A layered shell theory is implemented for several constitutive models including +the composite models to more accurately represent the shear stiffness of laminat- +ed shells. +• Damage mechanics is available to smooth the post-failure reduction of the +resultant forces in the constitutive model *MAT_SPOTWELD_DAMAGE. +INTRODUCTION +• Finite elastic strain isotropic plasticity model is available for solid elements. +*MAT_FINITE_ELASTIC_STRAIN_PLASTICITY. +• A shape memory alloy material is available: *MAT_SHAPE_MEMORY. +• Reference geometry for material, *MAT_MODIFIED_HONEYCOMB, can be set +at arbitrary relative volumes or when the time step size reaches a limiting value. +This option is now available for all element types including the fully integrated +solid element. +• Non orthogonal material axes are available in the airbag fabric model. See +*MAT_FABRIC. +• Other new constitutive models include for the beam elements: +◦ *MAT_MODIFIED_FORCE_LIMITED +◦ *MAT_SEISMIC_BEAM +◦ *MAT_CONCRETE_BEAM +• for shell and solid elements: +◦ *MAT_ELASTIC_VISCOPLASTIC_THERMAL +• for the shell elements: +◦ *MAT_GURSON +◦ *MAT_GEPLASTIC_SRATE2000 +◦ *MAT_ELASTIC_VISCOPLASTIC_THERMAL +◦ *MAT_COMPOSITE_LAYUP +◦ *MAT_COMPOSITE_LAYUP +◦ *MAT_COMPOSITE_DIRECT +• for the solid elements: +◦ *MAT_JOHNSON_HOLMQUIST_CERAMICS +◦ *MAT_JOHNSON_HOLMQUIST_CONCRETE +◦ *MAT_INV_HYPERBOLIC_SIN +◦ *MAT_UNIFIED_CREEP +◦ *MAT_SOIL_BRICK +◦ *MAT_DRUCKER_PRAGER +◦ *MAT_RC_SHEAR_WALL +• and for all element options a very fast and efficient version of the Johnson-Cook +plasticity model is available: +• *MAT_SIMPLIFIED_JOHNSON_COOK +• A fully integrated version of the type 16 shell element is available for the +resultant constitutive models. +INTRODUCTION +• A nonlocal failure theory is implemented for predicting failure in metallic +materials. The keyword *MAT_NONLOCAL activates this option for a subset of +elastoplastic constitutive models. +• A discrete Kirchhoff triangular shell element (DKT) for explicit analysis with +three in plane integration points is flagged as a type 17 shell element. This +element has much better bending behavior than the C0 triangular element. +• A discrete Kirchhoff linear triangular and quadrilateral shell element is available +as a type 18 shell. This shell is for extracting normal modes and static analysis. +• A C0 linear 4-node quadrilateral shell element is implemented as element type 20 +with drilling stiffness for normal modes and static analysis. +• An assumed strain linear brick element is available for normal modes and statics. +• The fully integrated thick shell element has been extended for use in implicit +calculations. +• A fully integrated thick shell element based on an assumed strain formulation is +now available. This element uses a full 3D constitutive model which includes the +normal stress component and, therefore, does not use the plane stress assump- +tion. +• The 4-node constant strain tetrahedron element has been extended for use in +implicit calculations. +• Relative damping between parts is available, see *DAMPING_RELATIVE (SMP +only). +• Preload forces are can be input for the discrete beam elements. +• Objective stress updates are implemented for the fully integrated brick shell +element. +• Acceleration time histories can be prescribed for rigid bodies. +• Prescribed motion for nodal rigid bodies is now possible. +• Generalized set definitions, i.e., SET_SHELL_GENERAL etc. provide much +flexibility in the set definitions. +• The command “sw4.” will write a state into the dynamic relaxation file, D3DRLF, +during the dynamic relaxation phase if the D3DRLF file is requested in the input. +• Added mass by PART ID is written into the MATSUM file when mass scaling is +used to maintain the time step size, (SMP version only). +• Upon termination due to a large mass increase during a mass scaled calculation a +print summary of 20 nodes with the maximum added mass is printed. +• Eigenvalue analysis of models containing rigid bodies is now available using +BCSLIB-EXT solvers from Boeing. (SMP version only). +INTRODUCTION +• Second order stress updates can be activated by part ID instead of globally on +the *CONTROL_ACCURACY input. +• Interface frictional energy is optionally computed for heat generation and is +output into the interface force file (SMP version only). +• The interface force binary database now includes the distance from the contact +surface for the FORMING contact options. This distance is given after the nodes +are detected as possible contact candidates. (SMP version only). +• Type 14 acoustic brick element is implemented. This element is a fully integrat- +ed version of type 8, the acoustic element (SMP version only). +• A flooded surface option for acoustic applications is available (SMP version +only). +• Attachment nodes can be defined for rigid bodies. This option is useful for NVH +applications. +• CONSTRAINED_POINTS tie any two points together. These points must lie on +a shell elements. +• Soft constraint is available for edge to edge contact in type 26 contact. +• CONSTAINED_INTERPOLATION option for beam to solid interfaces and for +spreading the mass and loads. (SMP version only). +• A database option has been added that allows the output of added mass for shell +elements instead of the time step size. +• A new contact option allows the inclusion of all internal shell edges in contact +type *CONTACT_GENERAL, type 26. This option is activated by adding “_IN- +TERIOR” after the GENERAL keyword. +• A new option allows the use deviatoric strain rates rather than total rates in +material model 24 for the Cowper-Symonds rate model. +• The CADFEM option for ASCII databases is now the default. Their option +includes more significant figures in the output files. +• When using deformable spot welds, the added mass for spot welds is now +printed for the case where global mass scaling is activated. This output is in the +log file, d3hsp file, and the messag file. +• Initial penetration warnings for edge-to-edge contact are now written into the +MESSAG file and the d3hsp file. +• Each compilation of LS-DYNA is given a unique version number. +• Finite length discrete beams with various local axes options are now available for +material types 66, 67, 68, 93, and 95. In this implementation the absolute value of +SCOOR must be set to 2 or 3 in the *SECTION_BEAM input. +• New discrete element constitutive models are available: +INTRODUCTION +◦ *MAT_ELASTIC_SPRING_DISCRETE_BEAM +◦ *MAT_INELASTIC_SPRING_DISCRETE_BEAM +◦ *MAT_ELASTIC_6DOF_SPRING_DISCRETE_BEAM +◦ *MAT_INELASTIC_6DOF_SPRING_DISCRETE_BEAM +• The latter two can be used as finite length beams with local coordinate systems. +• Moving SPC's are optional in that the constraints are applied in a local system +that rotates with the 3 defining nodes. +• A moving local coordinate system, CID, can be used to determine orientation of +discrete beam elements. +• Modal superposition analysis can be performed after an eigenvalue analysis. +Stress recovery is based on type 18 shell and brick (SMP only). +• Rayleigh damping input factor is now input as a fraction of critical damping, i.e. +0.10. The old method required the frequency of interest and could be highly +unstable for large input values. +• Airbag option “SIMPLE_PRESSURE_VOLUME” allows for the constant CN to +be replaced by a load curve for initialization. Also, another load curve can be +defined which allows CN to vary as a function of time during dynamic relaxa- +tion. After dynamic relaxation CN can be used as a fixed constant or load curve. +• Hybrid inflator model utilizing CHEMKIN and NIST databases is now available. +Up to ten gases can be mixed. +• Option to track initial penetrations has been added in the automatic SMP contact +types rather than moving the nodes back to the surface. This option has been +available in the MPP contact for some time. This input can be defined on the +fourth card of the *CONTROL_CONTACT input and on each contact definition +on the third optional card in the *CONTACT definitions. +• If the average acceleration flag is active, the average acceleration for rigid body +nodes is now written into the D3THDT and NODOUT files. In previous versions +of LS-DYNA, the accelerations on rigid nodes were not averaged. +• A capability to initialize the thickness and plastic strain in the crash model is +available through the option *INCLUDE_STAMPED_PART, which takes the +results from the LS-DYNA stamping simulation and maps the thickness and +strain distribution onto the same part with a different mesh pattern. +• A capability to include finite element data from other models is available +through the option, *INCLUDE_TRANSFORM. This option will take the model +defined in an INCLUDE file: offset all ID's; translate, rotate, and scale the coordi- +nates; and transform the constitutive constants to another set of units. +INTRODUCTION +Features added during 2001-2002 for the 970 release of LS-DYNA: +Some of the new features, which are also listed below, were also added to later releases +of version 960. Most new explicit capabilities work for both the MPP and SMP versions; +however, the implicit capabilities for MPP require the development of a scalable +eigenvalue solver and a parallel implementation of the constraint equations into the +global matrices. This work is underway. A later release of version 970 is planned in +2003 that will be scalable for implicit solutions. +Below is list of new capabilities and features: +• MPP decomposition can be controlled using *CONTROL_MPP_DECOMPOSI- +TION commands in the input deck. +• The MPP arbitrary Lagrangian-Eulerian fluid capability now works for airbag +deployment in both SMP and MPP calculations. +• Euler-to-Euler coupling +is now available through the keyword *CON- +STRAINED_EULER_TO_EULER. +• Up to ten ALE multi-material groups may now be defined. The previous limit +was three groups. +• Volume fractions can be automatically assigned during initialization of multi- +material cells. See the GEOMETRY option of *INITIAL_VOLUME_FRACTION. +• A new ALE smoothing option is available to accurately predict shock fronts. +• DATABASE_FSI activates output of fluid-structure interaction data to ASCII file +DBFSI. +• Point sources for airbag inflators are available. The origin and mass flow vector +of these inflators are permitted to vary with time. +• A majority of the material models for solid materials are available for calcula- +tions using the SPH (Smooth Particle Hydrodynamics) option. +• The Element Free Galerkin method (EFG or meshfree) is available for two- +dimensional and three-dimensional solids. This new capability is not yet im- +plemented for MPP applications. +• A binary option for the ASCII files is now available. This option applies to all +ASCII files and results in one binary file that contains all the information normal- +ly spread between a large number of separate ASCII files. +• Material models can now be defined by numbers rather than long names in the +keyword input. For example the keyword *MAT_PIECEWISE_LINEAR_PLAS- +TICITY can be replaced by the keyword: *MAT_024. +• An embedded NASTRAN reader for direct reading of NASTRAN input files is +available. This option allows a typical input file for NASTRAN to be read direct- +ly and used without additional input. See the *INCLUDE_NASTRAN keyword. +INTRODUCTION +• Names in the keyword input can represent numbers if the *PARAMETER option +is used to relate the names and the corresponding numbers. +• Model documentation for the major ASCII output files is now optional. This +option allows descriptors to be included within the ASCII files that document the +contents of the file. +• ID’s have been added to the following keywords: +◦ *BOUNDARY_PRESCRIBED_MOTION +◦ *BOUNDARY_PRESCRIBED_SPC +◦ *CONSTRAINED_GENERALIZED_WELD +◦ *CONSTRAINED_JOINT +◦ *CONSTRAINED_NODE_SET +◦ *CONSTRAINED_RIVET +◦ *CONSTRAINED_SPOTWELD +◦ *DATABASE_CROSS_SECTION +◦ *ELEMENT_MASS +• Penetration warnings for the contact option, ignore initial penetration, î are +added as an option. Previously, no penetration warnings were written when this +contact option was activated. +• Penetration warnings for nodes in-plane with shell mid-surface are printed for +the AUTOMATIC contact options. Previously, these nodes were ignored since it +was assumed that they belonged to a tied interface where an offset was not used; +consequently, they should not be treated in contact. +• For the arbitrary spot weld option, the spot welded nodes and their contact +segments are optionally written into the d3hsp file. See *CONTROL_CON- +TACT. +• For the arbitrary spot weld option, if a segment cannot be found for the spot +welded node, an option now exists to error terminate. See *CONTROL_CON- +TACT. +• Spot weld resultant forces are written into the SWFORC file for solid elements +used as spot welds. +• Solid materials have now been added to the failed element report. +• A new option for terminating a calculation is available, *TERMINATION_- +CURVE. +• A 10-noded tetrahedron solid element is available with either a 4 or 5 point +integration rule. This element can also be used for implicit solutions. +• A new 4 node linear shell element is available that is based on Wilson’s plate +element combined with a Pian-Sumihara membrane element. This is shell type +21. +INTRODUCTION +• A shear panel element has been added for linear applications. This is shell type +22. This element can also be used for implicit solutions. +• A null beam element for visualization is available. The keyword to define this +null beam is *ELEMENT_PLOTEL. This element is necessary for compatibility +with NASTRAN. +• A scalar node can be defined for spring-mass systems. The keyword to define +this node is *NODE_SCALAR. This node can have from 1 to 6 scalar degrees-of- +freedom. +• A thermal shell has been added for through-thickness heat conduction. +Internally, 8 additional nodes are created, four above and four below the mid- +surface of the shell element. A quadratic temperature field is modeled through +the shell thickness. Internally, the thermal shell is a 12 node solid element. +• A beam OFFSET option is available for the *ELEMENT_BEAM definition to +permit the beam to be offset from its defining nodal points. This has the ad- +vantage that all beam formulations can now be used as shell stiffeners. +• A beam ORIENTATION option for orienting the beams by a vector instead of the +third node is available in the *ELEMENT_BEAM definition for NASTRAN +compatibility. +• Non-structural mass has been added to beam elements for modeling trim mass +and for NASTRAN compatibility. +• An optional checking of shell elements to avoid abnormal terminations is +available. See *CONTROL_SHELL. If this option is active, every shell is checked +each time step to see if the distortion is so large that the element will invert, +which will result in an abnormal termination. If a bad shell is detected, either the +shell will be deleted or the calculation will terminate. The latter is controlled by +the input. +• An offset option is added to the inertia definition. See *ELEMENT_INERTIA_- +OFFSET keyword. This allows the inertia tensor to be offset from the nodal +point. +• Plastic strain and thickness initialization is added to the draw bead contact +option. See *CONTACT_DRAWBEAD_INITIALIZE. +• Tied contact with offsets based on both constraint equations and beam elements +for solid elements and shell elements that have 3 and 6 degrees-of-freedom per +node, respectively. See BEAM_OFFSET and CONSTRAINED_OFFSET contact +options. These options will not cause problems for rigid body motions. +• The segment-based (SOFT = 2) contact is implemented for MPP calculations. +This enables airbags to be easily deployed on the MPP version. +• Improvements are made to segment-based contact for edge-to-edge and sliding +conditions, and for contact conditions involving warped segments. +INTRODUCTION +• An improved interior contact has been implemented to handle large shear +deformations in the solid elements. A special interior contact algorithm is avail- +able for tetrahedron elements. +• Coupling with MADYMO 6.0 uses an extended coupling that allows users to link +most MADYMO geometric entities with LS-DYNA FEM simulations. In this +coupling MADYMO contact algorithms are used to calculate interface forces +between the two models. +• Release flags for degrees-of-freedom for nodal points within nodal rigid bodies +are available. This makes the nodal rigid body option nearly compatible with +the RBE2 option in NASTRAN. +• Fast updates of rigid bodies for metalforming applications can now be accom- +plished by ignoring the rotational degrees-of-freedom in the rigid bodies that are +typically inactive during sheet metal stamping simulations. See the keyword: +*CONTROL_RIGID. +• Center of mass constraints can be imposed on nodal rigid bodies with the SPC +option in either a local or a global coordinate system. +• Joint failure based on resultant forces and moments can now be used to simulate +the failure of joints. +• CONSTRAINED_JOINT_STIFFNESS now has a TRANSLATIONAL option for +the translational and cylindrical joints. +• Joint friction has been added using table look-up so that the frictional moment +can now be a function of the resultant translational force. +• The nodal constraint options *CONSTRAINED_INTERPOLATION and *CON- +STRAINED_LINEAR now have a local option to allow these constraints to be +applied in a local coordinate system. +• Mesh coarsening can now be applied to automotive crash models at the +beginning of an analysis to reduce computation times. See the new keyword: +*CONTROL_COARSEN. +• Force versus time seatbelt pretensioner option has been added. +• Both static and dynamic coefficients of friction are available for seat belt slip +rings. Previously, only one friction constant could be defined. +• *MAT_SPOTWELD now includes a new failure model with rate effects as well as +additional failure options. +• Constitutive models added for the discrete beam elements: +◦ *MAT_1DOF_GENERALIZED_SPRING +◦ *MAT_GENERAL_NONLINEAR_6dof_DISCRETE_BEAM +◦ *MAT_GENERAL_NONLINEAR_1dof_DISCRETE_BEAM +◦ *MAT_GENERAL_SPRING_DISCRETE_BEAM +INTRODUCTION +◦ *MAT_GENERAL_JOINT_DISCRETE_BEAM +◦ *MAT_SEISMIC_ISOLATOR +• for shell and solid elements: +◦ *MAT_plasticity_with_damage_ortho +◦ *MAT_simplified_johnson_cook_orthotropic_damage +◦ *MAT_HILL_3R +◦ *MAT_GURSON_RCDC +• for the solid elements: +◦ *MAT_SPOTWELD +◦ *MAT_HILL_FOAM +◦ *MAT_WOOD +◦ *MAT_VISCOELASTIC_HILL_FOAM +◦ *MAT_LOW_DENSITY_SYNTHETIC_FOAM +◦ *MAT_RATE_SENSITIVE_POLYMER +◦ *MAT_QUASILINEAR VISCOELASTIC +◦ *MAT_TRANSVERSELY_ANISOTROPIC_CRUSHABLE_FOAM +◦ *MAT_VACUUM +◦ *MAT_MODIFIED_CRUSHABLE_FOAM +◦ *MAT_PITZER_CRUSHABLE FOAM +◦ *MAT_JOINTED_ROCK +◦ *MAT_SIMPLIFIED_RUBBER +◦ *MAT_FHWA_SOIL +◦ *MAT_SCHWER_MURRAY_CAP_MODEL +• Failure time added to MAT_EROSION for solid elements. +• Damping in the material models *MAT_LOW_DENSITY_FOAM and *MAT_- +LOW_DENSITY_VISCOUS_FOAM can now be a tabulated function of the +smallest stretch ratio. +• The material model *MAT_PLASTICITY_WITH_DAMAGE allows the table +definitions for strain rate. +• Improvements in the option *INCLUDE_STAMPED_PART now allow all history +data to be mapped to the crash part from the stamped part. Also, symmetry +planes can be used to allow the use of a single stamping to initialize symmetric +parts. +• Extensive improvements in trimming result in much better elements after the +trimming is completed. Also, trimming can be defined in either a local or global +coordinate system. This is a new option in *DEFINE_CURVE_TRIM. +• An option to move parts close before solving the contact problem is available, see +*CONTACT_AUTO_MOVE. +INTRODUCTION +• An option to add or remove discrete beams during a calculation is available with +the new keyword: *PART_SENSOR. +• Multiple jetting is now available for the Hybrid and Chemkin airbag inflator +models. +• Nearly all constraint types are now handled for implicit solutions. +• Calculation of constraint and attachment modes can be easily done by using the +option: *CONTROL_IMPLICIT_MODES. +• Penalty option, see *CONTROL_CONTACT, now applies to all *RIGIDWALL +options and is always used when solving implicit problems. +• Solid elements types 3 and 4, the 4 and 8 node elements with 6 degrees-of- +freedom per node are available for implicit solutions. +• The warping stiffness option for the Belytschko-Tsay shell is implemented for +implicit solutions. The Belytschko-Wong-Chang shell element is now available +for implicit applications. The full projection method is implemented due to it +accuracy over the drill projection. +• Rigid to deformable switching is implemented for implicit solutions. +• Automatic switching can be used to switch between implicit and explicit +calculations. See the keyword: *CONTROL_IMPLICIT_GENERAL. +• Implicit dynamics rigid bodies are now implemented. See the keyword *CON- +TROL_IMPLICIT_DYNAMIC. +• Eigenvalue solutions can be intermittently calculated during a transient analysis. +• A linear buckling option is implemented. See the new control input: *CON- +TROL_IMPLICIT_BUCKLE +• Implicit initialization can be used instead of dynamic relaxation. See the +keyword *CONTROL_DYNAMIC_RELAXATION where the parameter, IDFLG, +is set to 5. +• Superelements, i.e., *ELEMENT_DIRECT_MATRIX_INPUT, are now available +for implicit applications. +• There is an extension of the option, *BOUNDARY_CYCLIC, to symmetry planes +in the global Cartesian system. Also, automatic sorting of nodes on symmetry +planes is now done by LS-DYNA. +• Modeling of wheel-rail contact for railway applications is now available, see +*RAIL_TRACK and *RAIL_TRAIN. +• A new, reduced CPU, element formulation is available for vibration studies +when elements are aligned with the global coordinate system. See *SECTION_- +SOLID and *SECTION_SHELL formulation 98. +• An option to provide approximately constant damping over a range of frequen- +cies is implemented, see *DAMPING_FREQUENCY_RANGE. +INTRODUCTION +Features added during 2003-2005 for the 971 release of LS-DYNA: +fully +functional +Initially, the intent was to quickly release version 971 after 970 with the implicit +for distributed memory processing using MPI. +capabilities +Unfortunately, the effort required for parallel implicit was grossly underestimated, and, +as a result, the release has been delayed. Because of the delay, version 971 has turned +into a major release. Some of the new features, listed below, were also added to later +releases of version 970. The new explicit capabilities are implemented in the MPP +version and except for one case, in the SMP version as well. +Below is list of new capabilities and features: +• A simplified method for using the ALE capability with airbags is now available +with the keyword *AIRBAG_ALE. +• Case control using the *CASE keyword, which provides a way of running +multiple load cases sequentially within a single run +• New option to forming contact: *CONTACT_FORMING_ONE_WAY_SUR- +FACE_TO_SURFACE_SMOOTH, which use fitted surface in contact calculation. +• Butt weld definition by using the *CONSTRAINED_BUTT_WELD option which +makes the definition of butt welds simple relative to the option: *CON- +STRAINED_GENERALIZED_WELD_BUTT. +• H-adaptive fusion is now possible as an option with the control input, *CON- +TROL_ADAPTIVE. +• Added a parameter on, *CONTROL_ADAPTIVE, to specify the number of +elements generated around a 90 degree radius. A new option to better calculate +the curvature was also implemented. +• Added a new keyword: *CONTROL_ADAPTIVE_CURVE, to refine the element +along trimming curves +• Birth and death times for implicit dynamics on the keyword *CONTROL_IM- +PLICIT_DYNAMICS. +• Added an option to scale the spot weld failure resultants to account for the +location of the weld on the segment surface, see *CONTROL_SPOTWELD_- +BEAM. +• Added an option which automatically replaces a single beam spot weld by an +assembly of solid elements using the same ID as the beam that was replaced, see +*CONTROL_SPOTWELD_BEAM. +• Boundary constraint in a local coordinate system using *CONSTRAINED_LO- +CAL keyword. +• A cubic spline interpolation element is now available, *CONSTRAINED_- +SPLINE. +INTRODUCTION +• Static implicit analyses in of a structure with rigid body modes is possible using +the option, *CONTROL_IMPLICIT_INERTIA_RELIEF. +• Shell element thickness updates can now be limited to part ID’s within a +specified set ID, see the *CONTROL_SHELL keyword. The thickness update for +shells can now be optionally limited to the plastic part of the strain tensor for +better stability in crash analysis. +• Solid element stresses in spot welds are optionally output in the local system +using the SWLOCL parameter on the *CONTROL_SOLID keyword. +• SPOTHIN option on the *CONTROL_CONTACT keyword cards locally thins +the spot welded parts to prevent premature breakage of the weld by the contact +treatments. +• New function: *CONTROL_FORMING_PROJECT, which can initial move the +penetrating slave nodes to the master surface +• New function *CONTROL_FORMING_TEMPLATE, which allows user to easily +set up input deck. Its function includes auto-position, define travel curve, termi- +nation time, and most of the forming parameters for most of the typical forming +process. +• New function *CONTROL_FORMING_USER, *CONTROL_FORMING_POSI- +TION, and *CONTROL_FORMING_TRAVEL, when used together, can allow +the user to define atypical forming process. +• Added new contact type *CONTACT_GUIDED_CABLE. +• Circular cut planes are available for *DATABASE_CROSS_SECTION definitions. +• New binary database FSIFOR for fluid structure coupling. +• Added *DATABASE_BINARY_D3PROP for writing the material and property +data to the first D3PLOT file or to a new database D3PROP. +• DATABASE_EXTENT_BINARY has new flags to output peak pressure, surface +energy density, nodal mass increase from mass scaling, thermal fluxes, and +temperatures at the outer surfaces of the thermal shell. +• Eight-character alphanumeric labels can now be used for the parameters SECID, +MID, EOSID, HGID, and TMID on the *PART keyword. +• Two NODOUT files are now written: one for high frequency output and a +second for low frequency output. +• Nodal mass scaling information can now be optionally written to the D3PLOT +file. +• Added option, MASS_PROPERTIES, to include the mass and inertial properties +in the GLSTAT and SSSTAT files. +• Added option in *CONTROL_CPU to output the cpu and elapsed time into the +GLSTAT file. +INTRODUCTION +• Added an option, IERODE, on the *CONTROL_OUTPUT keyword to include +eroded energies by part ID into the MATSUM file. Lumped mass kinetic energy +is also in the MATSUM file as part ID 0. +• Added an option, TET10, on the *CONTROL_OUTPUT keyword to output ten +connectivity nodes into D3PLOT database rather than 4. +• New keyword, *ELEMENT_SOLID_T4TOT10 to convert 4 node tetrahedron +elements to 10 node tetrahedron elements. +• New keyword, *ELEMENT_MASS_PART defines the total additional non- +structural mass to be distributed by an area weighted distribution to all nodes of +a given part ID. +• New keyword option, SET, for *INTIAL_STRESS_SHELL_SET allows a set of +shells to be initialized with the state of stress. +• New option allows the number of cpu’s to be specified on the *KEYWORD input. +• Tubular drawbead box option for defining the elements that are included in the +drawbead contact, see *DEFINE_BOX_DRAWBEAD. +• New function: *DEFINE_CURVE_DRAWBEAD, allow user to conveniently +define drawbead by using curves (in x, y format or iges format) +• New function: *DEFINE_DRAWBEAD_BEAM, which allows user to convenient- +ly define drawbead by using beam part ID, and specify the drawbead force. +• Analytic function can be used in place of load curves with the option *DEFINE_- +CURVE_FUNCTION. +• Friction can now be defined between part pair using the *DEFINE_FRICTION +input. +• New keyword: *DEFINE_CURVE_TRIM_3D, to allow trimming happens based +on blank element normal, rather than use pre-defined direction +• A new trimming algorithm was added: *DEFINE_CURVE_TRIM_NEW, which +allow seed node to be input and is much faster then the original algorithm. +• A new keyword, *DEFINE_HEX_SPOTWELD_ASSEMBLY, is available to define +a cluster of solid elements that comprise a single spot weld. +• The definition of a vector, see *DEFINE_VECTOR, can be done by defining +coordinates in a local coordinate system. +• The definition of a failure criteria between part pairs is possible with a table +defined using the keyword, *DEFINE_SPOTWELD_FAILURE_RESULTANTS. +• A new keyword, *DEFINE_CONNECTION_PROPERTIES is available for +defining failure properties of spot welds. +• Added *DEFINE_SET_ADAPTIVE to allow the adaptive level and element size +to be specified by part ID or element set ID. +INTRODUCTION +• Static rupture stresses for beam type spot welds can be defined in the keyword +input, *DEFINE_SPOTWELD_RUPTURE_STRESS. +• Section properties can be define in the *ELEMENT_BEAM definitions for +resultant beam elements using the SECTION option. +• Physical offsets of the shell reference surface can be specified on the shell +element cards, see the OFFSET option on *ELEMENT_SHELL. +• File names can be located in remote directories and accessed through the *IN- +CLUDE_PART keyword. +• New features to *INCLUDE_STAMPED_PART: two different mirror options, +user-defined searching radius. +• *INTIAL_STRESS_SECTION allows for stress initialization across a cross-section, +which consists of solid elements. +• An option, IVATN, is available for setting the velocities of slaved nodes and +parts for keyword, *INITIAL_VELOCITY_GENERATION. +• Twenty-two built-in cross-section are now available in the definition of beam +integration rules, see *INTEGRATION_BEAM. +• The possibility of changing material types is now available for shells using the +user defined integration rule, see *INTEGRATION_SHELL. +• The interface springback file created by using the keyword, *INTERFACE_- +SPRINGBACK is now optionally written as a binary file. +• An optional input line for *KEYWORD allows the definition of a prefix for all file +names created during a simulation. This allows multiple jobs to be executed in +the same directory. +• Body force loads can now be applied in a local coordinate system for *LOAD_- +BODY. +• A pressure loading feature allows moving pressures to be applied to a surface to +simulate spraying a surface with stream of fluid through a nozzle. See keyword +*LOAD_MOVING_PRESSURE. +• Thermal expansion can be added to any material by the keyword, *MAT_ADD_- +THERMAL_EXPANSION. +• Curves can now be used instead of eight digitized data points in the material +model *MAT_ELASTIC_WITH_VISCOSITY_CURVE +• New options for spot weld failure in *MAT_SPOTWELD, which apply to beam +and solid elements. +• Failure criteria based on plastic strain to failure is added to material *MAT_- +ANISOTROPIC_VISCOPLASTIC. +• Strain rate failure criterion is added to material *MAT_MODIFIED_PIECE- +WISE_LINEAR_PLASTICITY. +INTRODUCTION +• Strain rate scaling of the yield stress can now be done differently in tension and +compression in material with separate pressure cut-offs in tension and compres- +sion in material model *MAT_PLASTICITY_TENSION_COMPRESSION. +• The RCDC model is now available to predict failure in material *MAT_PLASTIC- +ITY_WITH_DAMAGE. +• Two additional yield surfaces have been added to material *MAT_MODIFIED_- +HONEYCOMB to provide more accurate predictions of the behavior of honey- +comb barrier models. +• Unique coordinate systems can be assigned to the two nodal points of material +*MAT_1DOF_GENERALIZED_SPRING. +• Poisson’s ratio effects are available in foam defined by load curves in the +material *MAT_SIMPLIFIED_RUBBER/FOAM +• Failure effects are available in the rubber/foam material defined by load curves +in the *MAT_SIMPLIFIED_RUBBER/FOAM_WITH_FAILURE. +• The material option *MAT_ADD_EROSION now allows the maximum pressure +at failure and the minimum principal strain at failure to be specified. +• Strains rather than displacements can now be used with the material model for +discrete beams, *MAT_GENERAL_NONLINEAR_6DOF_DISCRETE_BEAM. +• New option +for *MAT_TRANSVERSELY_ANISOTROPIC_ELASTIC_PLAS- +TIC_(ECHANGE), which allow two ways to change the Young’s modulus dur- +ing forming simulation. +• New Material model: *MAT_HILL_3R: includes the shear term in the yield +surface calculation by using Hill’s 1948 an-isotropic material model. +• New Material model: *MAT_KINEMATIC_HARDENING_TRANSVERSELY_- +ANISOTROPIC: which integrates Mat #37 with Yoshida’s two-surface kinematic +hardening model. +• Improved formulation for the fabric material, *MAT_FABRIC for formulations 2, +3, and 4. The improved formulations are types 12, 13, and 14. +• Constitutive models added for truss elements: +◦ *MAT_MUSCLE +• For beam elements +◦ *MAT_MOMENT_CURVATURE +• For shell elements +◦ *MAT_RESULTANT_ANISOTROPIC +◦ *MAT_RATE_SENSITIVE_COMPOSITE_FABRIC. +◦ *MAT_SAMP-1 +INTRODUCTION +◦ *MAT_SHAPE_MEMORY is now implemented for shells. +• for shell and solid elements: +◦ *MAT_BARLAT_YLD2000 for anisotropic aluminum alloys. +◦ *MAT_SIMPLIFIED_RUBBER_WITH_DAMAGE +◦ *MAT_VISCOELASTIC_THERMAL +◦ *MAT_THERMO_ELASTO_VISCOPLASTIC_CREEP +• for the solid elements: +◦ *MAT_ARUP_ADHESIVE +◦ *MAT_BRAIN_LINEAR_VISCOELASTIC. +◦ *MAT_CSCM for modeling concrete. +◦ *MAT_PLASTICITY_COMPRESSION_TENSION_EOS for modeling ice. +◦ *MAT_COHESIVE_ELASTIC +◦ *MAT_COHESIVE_TH +◦ *MAT_COHESIVE_GENERAL +◦ *MAT_EOS_GASKET +◦ *MAT_SIMPLIFIED_JOHNSON_COOK is now implemented for solids. +◦ *MAT_PLASTICITY_WITH_DAMAGE is now implemented for solids. +◦ *MAT_SPOTWELD_DAIMLERCHRYSLER +• User defined equations-of-state are now available. +• There is now an interface with the MOLDFLOW code. +• Damping defined +in *DAMPING_PART_STIFFNESS now works for the +Belytschko –Schwer beam element. +• The option *NODE_TRANSFORMATION allows a node set to be transformed +based on a transformation defined in *DEFINE_TRANSFORMATION. +• Parameters can be defined in FORTRAN like expressions using *PARAMETER_- +EXPRESSION. +• A part can be moved in a local coordinate system in *PART_MOVE. +• A simplified method for defining composite layups is available with *PART_- +COMPOSITE +• The rigid body inertia can be changed in restart via *CHANGE_RIGID_BODY_- +INERTIA. +• A part set can now be defined by combining other part sets in *SET_PART_ADD. +• Termination of the calculation is now possible if a specified number of shell +elements are deleted in a give part ID. See *TERMINATION_DELETED_- +SHELLS. +INTRODUCTION +• Added hourglass control type 7 for solid elements for use when modeling +hyperelastic materials. +• Shell formulations 4, 11, 16, and 17 can now model rubber materials. +• Added a new seatbelt pretensioner type 7 in which the pretensioner and +retractor forces are calculated independently and added. +• A new composite tetrahedron element made up from 12 tetrahedron is now +available as solid element type 17. +• Shell thickness offsets for *SECTION_SHELL now works for most shell elements, +not just the Hughes-Liu shell. +• The Hughes-Liu beam has been extended to include warpage for open cross- +sections. +• A resultant beam formulation with warpage is available as beam type 12. +• Two nonlinear shell elements are available with 8 degrees-of-freedom per node +to include thickness stretch. +• Tetrahedron type 13, which uses nodal pressures, is now implemented for +implicit applications. +• Cohesive solid elements are now available for treating failure. +• Seatbelt shell elements are available for use with the all seatbelt capabilities. +• Superelements can now share degrees-of-freedom and are implemented for +implicit applications under MPI. +• A user defined element interface is available for solid and shell elements. +• Thermal shells are available for treating heat flow through shell elements. +• EFG shell formulations 41 and 42 are implemented for explicit analysis. +• EFGPACK is implemented in addition to BCSLIB-EXT solver on the keyword +*CONTROL_EFG. +• EFG MPP version is available for explicit analysis. +• EFG fast transformation method is implemented in the EFG solid formulation. +• EFG Semi-Lagrangian kernel and Eulerian kernel options are added for the foam +materials. +• EFG 3D adaptivity is implemented for the metal materials. +• EFG E.O.S. and *MAT_ELASTIC_FLUID materials are included in the 4-noded +background element formulation. +• Airbag simulations by using ALE method can be switched to control volume +method by *ALE_CV_SWITCH. +• *MAT_ALE_VISCOUS now supports Non-Newtonian viscosity by power law or +load curve. +INTRODUCTION +• *DATABASE_BINARY_FSIFOR outputs fluid-structure +interaction data to +binary file. +• *DATABASE_FSI_SENSOR outputs ALE element pressure to ASCII file dbsor. +• *MAT_GAS_MIXTURE supports nonlinear heat capacities. +• *INITIAL_VOLUME_FRACTION_GEOMETRY uses an enhanced algorithm to +handle both concave and convex geometries and substantially reduce run time. +• A new keyword *DELETE_FSI allows the deletion of coupling definitions. +• Convection heat transfer activates by *LOAD_ALE_CONVECTION in ALE FSI +analysis. +• *ALE_FSI_SWITCH_MMG is implemented to switch between ALE multi- +material groups to treat immersed FSI problems. +• Type 9 option is added in *ALE_REFERENCE_SYSTEM_GROUP to deal +complex ALE mesh motions including translation, rotation, expansion and +contraction, etc. +◦ New options in *CONSTRAINED_LAGRANGE_IN_SOLID +◦ Shell thickness option for coupling type 4. +◦ Bulk modulus based coupling stiffness. +◦ Shell erosion treatment. +◦ Enable/disable interface force file. +• New coupling method for fluid flowing through porous media are implemented +as type 11 (shell) and type 12 (solid) in *CONSTRAINED_LAGRANGE_IN_SOL- +ID. +• *ALE_MODIFIED_STRAIN allows multiple strain fields in certain ALE elements +to solve sticking behavior in FSI. (MPP underdevelopment) +• *ALE_FSI_PROJECTION is added as a new constraint coupling method to solve +small pressure variation problem. (MPP underdevelopment) +• *BOUNDARY_PRESCRIBED_ORIENTATION_RIGID is added as a means to +prescribe as a function of time the general orientation of a rigid body using a +variety of methods. This feature is available in release R3 and higher of Version +971. +• *BOUNDARY_PRESCRIBED_ACCELEROMETER_RIGID is added as a means to +prescribe the motion of a rigid body based un experimental data gathered from +accelerometers affixed to the rigid body. This feature is available in release R3 +and higher of Version 971. +INTRODUCTION +Capabilities added during 2008-2011 for Version 971R6 of LS-DYNA: +During the last four years the implicit capabilities are now scalable to a large number of +cores; therefore, LS-DYNA has achieved a major goal over 15 years of embedding a +scalable implicit solver. Also, in addition to the progress made for implicit solutions +many other new and useful capabilities are now available. +• The keyword *ALE_AMBIENT_HYDROSTATIC +initializes the hydrostatic +pressure field in the ambient ALE domain due to an acceleration like gravity. +• The keyword *ALE_FAIL_SWITCH_MMG allows switching an ALE multi- +material-group ID (AMMGID) if the material failure criteria occurs. +• The keyword *ALE_FRAGMENTATION allow switching from the ALE multi- +material-group ID, AMMGID, (FR_MMG) of this failed material to another AM- +MGID (TO_MMG). This feature may typically be used in simulating fragmenta- +tion of materials. +• The keyword *ALE_REFINE refines ALE hexahedral solid elements automatical- +ly. +• The keyword *BOUNDARY_ALE_MAPPING maps ALE data histories from a +previous run to a region of elements. Data are read from or written to a map- +ping file with a file name given by the prompt “map=” on the command line +starting the execution. +• The keyword *BOUNDARY_PORE_FLUID is used to define parts that contain +pore fluid where defaults are given on *CONTROL_PORE_FLUID input. +• With the keyword, *BOUNDARY_PRESCRIBED_FINAL_GEOMETRY, the final +displaced geometry for a subset of nodal points is defined. The nodes of this +subset are displaced from their initial positions specified in the *NODE input to +the final geometry along a straight line trajectory. A load curve defines a scale +factor as a function of time that is bounded between zero and unity correspond- +ing to the initial and final geometry, respectively. A unique load curve can be +specified for each node, or a default load curve can apply to all nodes. +• The keyword, *BOUNDARY_PWP, defines pressure boundary conditions for +pore water at the surface of the software. +• The keyword, *CONSTRAINED_JOINT_COOR, defines a joint between two +rigid bodies. The connection coordinates are given instead of the nodal point IDs +used in *CONSTRAINED_JOINT. +• The keyword, *CONSTRAINED_SPR2, defines a self-piercing rivet with failure. +This model for a self-piercing rivet (SPR2) includes a plastic-like damage model +that reduces the force and moment resultants to zero as the rivet fails. The +domain of influence is specified by a diameter, which should be approximately +equal to the rivet’s diameter. The location of the rivet is defined by a single node +at the center of two riveted sheets. +INTRODUCTION +• Through the keyword, *CONTROL_BULK_VISCOSITY, bulk viscosity +is +optional for the Hughes-Liu beam and beam type 11 with warpage. This option +often provides better stability, especially in elastic response problems. +• The display of nodal rigid bodies is activated by the parameter, PLOTEL, on the +*CONTROL_RIGID keyword. +• The mortar contact, invoked by appending the suffix MORTAR to either FORM- +ING_SURFACE_TO_SURFACE, AUTOMATIC_SURFACE_TO_SURFACE or +AUTOMATIC_SINGLE_SURFACE, is a segment to segment penalty based +contact. For two segments on each side of the contact interface that are overlap- +ping and penetrating, a consistent nodal force assembly taking into account the +individual shape functions of the segments is performed. In this respect the +results with this contact may be more accurate, especially when considering +contact with elements of higher order. By appending the suffix TIED to the +CONTACT_AUTOMATIC_SURFACE_TO_SURFACE_MORTAR keyword or +the suffix MORTAR to the CONTACT_AUTOMATIC_SURFACE_TO_SUR- +FACE_TIEBREAK keyword, this is treated as a tied contact interface with tie- +break failure in the latter case. Only OPTION = 9 is supported for the mortar +tiebreak contact. The mortar contact is intended for implicit analysis in particu- +lar but is nevertheless supported for explicit analysis as well. +• In the database, ELOUT, the number of history variables can be specified for +output each integration point in the solid, shell, thick shell, and beam elements. +The number of variables is given on the *DATABASE_ELOUT keyword defini- +tion. +• A new option is available in *DATABASE_EXTENT_BINARY. Until now only +one set of integration points were output through the shell thickness. The +lamina stresses and history variables were averaged for fully integrated shell +elements, which results in less disk space for the D3PLOT family of files, but +makes it difficult to verify the accuracy of the stress calculation after averaging. +An option is now available to output all integration point stresses in fully inte- +grated shell elements: 4 x # of through thickness integration points in shell types +6, 7, 16, 18-21, and 3 x # of through thickness integration points in triangular shell +types 3, and 17. +• The keyword *DATABASE_PROFILE allows plotting the distribution or profile +of data along x, y, or z-direction. +• The purpose of the keyword, *DEFINE_ADAPTIVE_SOLID_TO_SPH, is to +adaptively transform a Lagrangian solid Part or Part Set to SPH particles when +the Lagrange solid elements comprising those parts fail. One or more SPH +particles (elements) will be generated for each failed element to. The SPH parti- +cles replacing the failed element inherit all of the properties of failed solid ele- +ment, e.g. mass, kinematic variables, and constitutive properties. +INTRODUCTION +• With the keywords beginning with, *DEFINE_BOX, a LOCAL option is now +available. With this option the diagonal corner coordinates are given in a local +coordinate system defined by an origin and vector pair. +• The keyword, *DEFINE_CURVE_DUPLICATE, defines a curve by optionally +scaling and offsetting the abscissa and ordinates of another curve defined by the +*DEFINE_CURVE keyword. +• The keyword, *DEFINE_ELEMENT_DEATH, is available to delete a single +element or an element set at a specified time during the calculation. +• The purpose of the keyword, *DEFINE_FRICTION_ORIENTATION, is to allow +for the definition of different coefficients of friction (COF) in specific directions, +specified using a vector and angles in degrees. In addition, COF can be scaled +according to the amount of pressure generated in the contact interface. +• With the new keyword, *DEFINE_FUNCTION, an arithmetic expression +involving a combination of independent variables and other functions, i.e., +f(a,b,c) = a*2 + b*c + sqrt(a*c) +is defined where a, b, and c are the independent variables. This option is im- +plemented for a subset of keywords. +◦ *ELEMENT_SEATBELT_SLIPRING +◦ *LOAD_BEAM +◦ *LOAD_MOTION_NODE +◦ *LOAD_MOVING_PRESSURE +◦ *LOAD_NODE +◦ *LOAD_SEGMENT +◦ *LOAD_SEGMENT_NONUNIFORM +◦ *LOAD_SETMENT_SET_NONUNIFORM +◦ *BOUNDARY_PRESCRIBED_MOTION +• If a curve ID is not found, then the function ID’s are checked. +• The keyword, *DEFINE_SPH_TO_SPH_COUPLING, defines a penalty based +contact to be used for the node to node contacts between SPH parts. +• The keyword, *DEFINE_TABLE_2D, permits the same curve ID to be referenced +by multiple tables, and the curves may be defined anywhere in the input. +• The keyword, *DEFINE_TABLE_3D, provides a way of defining a three- +dimensional table. A 2D table ID is specified for each abscissa value defined for +the 3D table. +• The keyword, *ELEMENT_BEAM_PULLEY, allows the definition of a pulley for +truss beam elements . Currently, the +beam pulley is implemented for *MAT_001 and *MAT_156. Pulleys allow +continuous sliding of a string of truss beam element through a sharp change of +angle. +INTRODUCTION +• The purpose of the keyword, *ELEMENT_MASS_MATRIX, is to define a 6x6 +symmetric nodal mass matrix assigned to a nodal point or each node within a +node set. +• The keyword, *ELEMENT_DISCRETE_SPHERE, allows the definition of a +discrete spherical element for discrete element calculations. Each particle con- +sists of a single node with its mass, mass moment of inertia, and radius. Initial +coordinates and velocities are specified via the nodal data. +• The +two keywords, *ELEMENT_SHELL_COMPOSITE and *ELEMENT_- +TSHELL_COMPOSITE, are used to define elements for a general composite shell +part where the shells within the part can have an arbitrary number of layers. The +material ID, thickness, and material angle are specified for the thickness integra- +tion points for each shell in the part +• The keyword, *EOS_USER_DEFINED, allows a user to supply their own +equation-of-state subroutine. +• The new keyword *FREQUENCY_DOMAIN provides a way of defining and +solving frequency domain vibration and acoustic problems. The related key- +word cards given in alphabetical order are: +◦ *FREQUENCY_DOMAIN_ACOUSTIC_BEM_{OPTION} +◦ *FREQUENCY_DOMAIN_ACOUSTIC_FEM +◦ *FREQUENCY_DOMAIN_FRF +◦ *FREQUENCY_DOMAIN_RANDOM_VIBRATION +◦ *FREQUENCY_DOMAIN_RESPONSE_SPECTRUM +◦ *FREQUENCY_DOMAIN_SSD +• The keyword, *INITIAL_AIRBAG_PARTICLE, initializes pressure in a closed +airbag volume, door cavities for pressure sensing studies, and tires. +• The keyword *INITIAL_ALE_HYDROSTATIC +initializes +the hydrostatic +pressure field in an ALE domain due to an acceleration like gravity. +• The keyword *INITIAL_ALE_MAPPING maps ALE data histories from a +previous run. Data are read from a mapping file with a file name given by the +prompt “map=” on the command line starting the execution. +• The keyword, *INITIAL_AXIAL_FORCE_BEAM, provides a simplified method +to model initial tensile forces in bolts. +• The keyword, *INITIAL_FIELD_SOLID, is a simplified version of the *INITIAL_- +STRESS_SOLID keyword which can be used with hyperelastic materials. This +keyword is used for history variable input. Data is usually in the form of the +eigenvalues of diffusion tensor data. These are expressed in the global coordi- +nate system. +• The equation-of-state, *EOS_MIE_GRUNEISEN, type 16, is a Mie-Gruneisen +form with a p-α compaction model. +INTRODUCTION +• The keyword, *LOAD_BLAST_ENHANCED, defines an air blast function for the +application of pressure loads due the explosion of conventional charge. While +similar to *LOAD_BLAST this feature includes enhancements for treating reflect- +ed waves, moving warheads and multiple blast sources. The loads are applied to +facets defined with the keyword *LOAD_BLAST_SEGMENT. A database con- +taining blast pressure history is also available . +• The keyword, *LOAD_ERODING_PART_SET, creates pressure loads on the +exposed surface composed of solid elements that erode, i.e., pressure loads are +added to newly exposed surface segments as solid elements erode. +• The keyword, *LOAD_SEGMENT_SET_ANGLE, applies traction loads over a +segment set that is dependent on the orientation of a vector. An example appli- +cation is applying a pressure to a cylinder as a function of the crank angle in an +automobile engine +• The keyword, *LOAD_STEADY_STATE_ROLLING, is a generalization of +*LOAD_BODY, allowing the user to apply body loads to part sets due to transla- +tional and rotational accelerations in a manner that is more general than the +*LOAD_BODY capability. The *LOAD_STEADY_STATE_ROLLING keyword +may be invoked an arbitrary number of times in the problem as long as no part +has the option applied more than once and they can be applied to arbitrary +meshes. This option is frequently used to initialize stresses in tire. +• The keywords INTERFACE_SSI, INTERFACE_SSI_AUX, INTERFACE_SSI_- +AUX_EMBEDDED and INTERFACE_SSI_STATIC are used to define the soil- +structure interface appropriately in various stages of soil-structure interaction +analysis under earthquake ground motion. +• The keyword, *LOAD_SEISMIC_SSI, is used to apply earthquake loads due to +free-field earthquake ground motion at certain locations — defined by either +nodes or coordinates — on a soil-structure interface. This loading is used in +earthquake soil-structure interaction analysis. The specified motions are used to +compute a set of effective forces in the soil elements adjacent to the soil-structure +interface, according to the effective seismic input–domain reduction method. +• The keyword *DEFINE_GROUND_MOTION is used to specify a ground motion +to be used in conjunction with *LOAD_SEISMIC_SSI. +• Material types *MAT_005 and *MAT_057 now accept table input to allow the +stress quantity versus the strain measure to be defined as a function of tempera- +ture. +• The material option *MAT_ADD_EROSION, can now be applied to all +nonlinear shell, thick shell, fully integrated solids, and 2D solids. New failure +criteria are available. +• The GISSMO damage model, now available as an option in *MAT_ADD_ERO- +SION, is a phenomenological formulation that allows for an incremental descrip- +INTRODUCTION +tion of damage accumulation, including softening and failure. It is intended to +provide a maximum in variability for the description of damage for a variety of +metallic materials (e.g. *MAT_024, *MAT_036, …). The input of parameters is +based on tabulated data, allowing the user to directly convert test data to numer- +ical input. +• The keyword, *MAT_RIGID_DISCRETE or MAT_220, eliminates the need to +define a unique rigid body for each particle when modeling a large number of +rigid particles. This gives a large reduction in memory and wall clock time over +separate rigid bodies. A single rigid material is defined which contains multiple +disjoint pieces. Input is simple and unchanged, since all disjoint rigid pieces are +identified automatically during initialization. +• The keyword, *NODE_MERGE, causes nodes with identical coordinates to be +replaced during the input phase by the node encountered that has the smallest +ID. +• The keyword, *PART_ANNEAL, is used to initialize the stress states at integra- +tion points within a specified part to zero at a given time during the calculation. +This option is valid for parts that use constitutive models where the stress is +incrementally updated. This option also applies to the Hughes-Liu beam ele- +ments, the integrated shell elements, thick shell elements, and solid elements. +• The keyword, *PART_DUPLICATE, provides a method of duplicating parts or +part sets without the need to use the *INCLUDE_TRANSFORM option. +• To automatically generate elements to visualize rigid walls the DISPLAY option +is now available for *RIGIDWALL_PLANAR and *RIGIDWALL_GEOMETRIC. +• A one point integrated pentahedron solid element with hourglass control is +implemented as element type 115 and can be referenced in *SECTION_SOLID. +Also, the 2 point pentahedron solid, type 15, no longer has a singular mode. +• The keyword *SECTION_ALE1D defines section properties for 1D ALE +elements. +• The keyword *SECTION_ALE2D defines section properties for 2D ALE +elements. +• The keywords *SET_BEAM_INTERSECT, *SET_SHELL_INTERSECT, *SET_SOL- +ID_INTERSECT, *SET_NODE_INTERSECT, and *SET_SEGMENT_INTER-SECT, +allows the definition of a set as the intersection, ∩, of a series of sets. The new +set, SID, contains all common members. +• The keyword, *SET_SEGMENT_ADD, is now available for defining a new +segment set by combining other segment sets. +• The two keywords, *DEFINE_ELEMENT_GENERALIZED_SHELL and *DE- +FINE_ +ELEMENT_GENERALIZED_SOLID, are used to define general shell and solid +element formulations to allow the rapid prototyping of new element formula- +INTRODUCTION +tions. They are used in combination with the new keywords *ELEMENT_GEN- +ERLIZED_SHELL and *ELEMENT_GENERALIZED_SOLID. +• The two keywords, *ELEMENT_INTERPOLATION_SHELL and *ELEMENT_ +INTERPOLATION_SOLID, are used to interpolate stresses and other solution +variables from the generalized shell and solid element formulations for visualiza- +tion. They are used together with the new keyword *CONSTRAINED_NODE_- +INTERPOLATION. +• The keyword, *ELEMENT_SHELL_NURBS_PATCH, is used to define 3D shell +elements based on NURBS (Non-Uniform Ration B-Spline) basis functions. +Currently four different element formulations, with and without rotational +degrees of freedom are available. +• The keyword LOAD_SPCFORC is used to apply equivalent SPC loads, read in +from the d3dump file during a full-deck restart, in place of the original con- +straints in order to facilitate the classical non-reflecting boundary on an outside +surface. +Capabilities added in 2012 to create Version 97R6.1, of LS-DYNA: +• A new keyword +*MAT_THERMAL_DISCRETE_BEAM defines +thermal +properties for ELFORM 6 beam elements. +• An option *CONTROL_THERMAL_SOLVER, invoked by TSF < 0, gives the +thermal speedup factor via a curve. This feature is useful when artificially +scaling velocity in metal forming. +• A nonlinear form of Darcy's law in *MAT_ADD_PORE_AIR allows curves to +define the relationship between pore air flow velocity and pore air pressure +gradient. +• An extention to the PART option in *SET_SEGMENT_GENERAL allows +reference to a beam part. This allows for creation of 2D segments for traction +application. +• Options “SET_SHELL”, “SET_SOLID”, “SET_BEAM”, “SET_TSHELL”, “SET_- +SPRING” are added to *SET_NODE_GENERAL so users can define a node set +using existing element sets. +• Options “SET_SHELL”, “SET_SOLID”, “SET_SLDIO”, “SET_TSHELL”, “SET_- +TSHIO” are added to *SET_SEGMENT_GENERAL so users can use existing +element sets to define a segment set. +• *BOUNDARY_PRESCRIBED_MOTION_SET_BOX prescribes motion to nodes +that fall inside a defined box. +• IPNINT > 1 in *CONTROL_OUTPUT causes d3hsp to list the IPNINT smallest +element timesteps in ascending order. +• Section and material titles are echoed to d3hsp. +INTRODUCTION +• A new parameter MOARFL in *DEFINE_CONNECTION_PROPERTIES permits +reduction in modeled area due to shear. +• A new option HALF_SPACE in *FREQUENCY_DOMAIN_ACOUSTIC_BEM +enables treatment of a half-space in boundary element method, frequency do- +main acoustic analysis. +• A shell script “kill_by_pid” is created during MPP startup. When executed, this +script will run “kill -9” on every LS-DYNA process started as part of the MPP +job. This is for use at the end of submission scripts, as a “fail safe” cleanup in +case the job aborts. +• A new parameter IAVIS in *CONTROL_SPH selects the artificial viscosity +formulation for the SPH particles. If set to 0, the Monaghan type artificial viscos- +ity formulation is used. If set to 1, the standard artificial viscosity formulation +for solid elements is used which may provide a better energy balance but is less +stable in specific applications such as high velocity impact. +• Contact friction may be included in *CONTACT_2D_NODE_TO_SOLID for +SPH. +• A new keyword *ALE_COUPLING_NODAL_CONSTRAINT provides a +coupling mechanism between ALE solids and non-ALE nodes. The nodes can be +from virtually any non-ALE element type including DISCRETE_SPHERE, EFG, +and SPH, as well as the standard Lagrangian element types. In many cases, this +coupling type may be a better alternative to *CONSTRAINED_LAGRANGE_- +IN_SOLID. +• The keyword *ALE_ESSENTIAL_BOUNDARY assigns essential boundary +conditions to nodes of the ALE boundary surface. The command can be repeat- +ed multiple times and is recommended over use of EBC in *CONTROL_ALE.. +• The keyword *DELETE_ALECPL in a small restart deck deletes coupling defined +with *ALE_COUPLING_NODAL_CONSTRAINT. The command can also be +used to reinstate the coupling in a later restart. +• *DEFINE_VECTOR_NODES defines a vector with two node points. +• *CONTACT_AUTOMATIC_SINGLE_SURFACE_TIED allows for the calculation +of eigenvalues and eigenvectors for models that include *CONTACT_AUTO- +MATIC_SINGLE_SURFACE. +• A new parameter RBSMS in *CONTROL_RIGID affects rigid body treatment in +Selective Mass Scaling (*CONTROL_TIMESTEP). When rigid bodies are in any +manner connected to deformable elements, RBSMS = 0 (default) results in spuri- +ous inertia due to improper treatment of the nodes at the interface. RBSMS = 1 +alleviates this effect but an additional cost is incurred. +• A new parameter T10JTOL in *CONTROL_SOLID sets a tolerance for issuing a +warning when J_min/J_max goes below this tolerance value (i.e., quotient +between minimum and maximum Jacobian value in the integration points) for +INTRODUCTION +tetrahedron type 16. This quotient serves as an indicator of poor tetrahedral +element meshes in implicit that might cause convergence problems. +• A new option MISMATCH for *BOUNDARY_ACOUSTIC_COUPLING handles +coupling of structural element faces and acoustic volume elements (ELFORMs 8 +and 14) in the case where the coupling surfaces do not have coincident nodes. +• A porosity leakage formulation in *MAT_FABRIC (*MAT_034, FLC < 0) is now +available for particle gas airbags (*AIRBAG_PARTICLE). +• *BOUNDARY_PRESCRIBED_ACCELEROMETER is disabled during dynamic +relaxation. +• A new parameter CVRPER in *BOUNDARY_PAP defines porosity of a cover +material encasing a solid part. +• A parameter TIEDID in *CONTACT_TIED_SURFACE_TO_SURFACE offers an +optional incremental normal update in SMP to eliminate spurious contact forces +that may appear in some applications. +• A new option SPOTSTP = 3 in *CONTROL_CONTACT retains spot welds even +when the spot welds are not found by *CONTACT_SPOTWELD. +• The SMP consistency option (ncpu < 0) now pertains to the ORTHO_FRICTION +contact option. +• Forces from *CONTACT_GUIDED_CABLE are now written to ncforc (both +ASCII and binout). +• Discrete beam materials 70, 71, 74, 94, 121 calculate axial force based on change +in length. Output the change in length instead of zero axial relative displace- +ment to ASCII file disbout (*DATABASE_DISBOUT). +• *DATABASE_RCFORC_MOMENT is now supported in implicit. +• After the first implicit step, the output of projected cpu and wall clock times is +written and the termination time is echoed. +• *DATABASE_MASSOUT is upgraded to include a summary table and to +optionally add mass for nodes belonging to rigid bodies. +• Generate and store resultant forces for the LaGrange Multiplier joint formulation +so as to give correct output to jntforc (*DATABASE_JNTFORC). +• Control the number of messages for deleted and failed elements using parameter +MSGMAX in *CONTROL_OUTPUT. +• Nodal and resultant force output is written to nodfor for nodes defined in +*FREQUENCY_DOMAIN_SSD +in +*DATABASE_NODAL_FORCE_GROUP +analysis (SMP only). +• Ncforc data is now written for guided cables (*CONTACT_GUIDED_CABLE) in +MPP. +INTRODUCTION +• Jobid handling is improved in l2a utility so that binout files from multiple jobs, +with or without a jobid-prefix, can be converted with the single command “l2a -j +*binout*”. The output contains the correct prefix according to the jobid. +• ALE_MULTI-MATERIAL_GROUP (AMMG) info is written to matsum (both +ASCII and binout). +• Shell formulation 14 is switched to 15 (*SECTION_SHELL) in models that +include axisymmetric SPH. +• *ELEMENT_BEAM_PULLEY is permitted with *MAT_CABLE_DISCRETE_- +BEAM. +• A warning during initialization is written if a user creates DKT triangles, either +by ELFORM = 17 on *SECTION_SHELL or ESORT = 2 on *CONTROL_SHELL, +that are thicker than the maximum edge length. +• Account is taken of degenerate acoustic elements with ELFORM 8. Tria and +quad faces at acoustic-structure boundary are handled appropriately according +to shape. +• The compression elimination option for 2D seatbelts, CSE = 2 in *MAT_SEAT- +BELT is improved. +• Detailed material failure (*MAT_ADD_EROSION) messages in messag and +d3hsp are suppressed when number of messages > MSGMAX (*CONTROL_- +OUTPUT). +• Implement SMP consistency +(*MAT_186) solids and shells. +(ncpu < 0) +in *MAT_COHESIVE_GENERAL +• Viscoelastic model in *MAT_077_O now allows up to twelve terms in Prony +series instead of standard six. +• Large curve ID's for friction table (*CONTACT_… with FS = 2) are enabled. +• Efficiency of GISSMO damage in *MAT_ADD_EROSION is improved. +• *MAT_ADD_PERMEABILITY_ORTHOTROPIC +is now available +for pore +pressure analysis (*…_PORE_FLUID). +• For *MAT_224 solids and shells, material damage serves as the failure variable in +*CONSTRAINED_TIED_NODES_FAILURE. +• The behavior of *MAT_ACOUSTIC is modified when used in combination with +dynamic relaxation (DR). Acoustic domain now remains unperturbed in the DR +phase but hydrostatic pressure from the acoustic domain is applied to the struc- +ture during DR. +• Option for 3D to 2D mapping is added in *INITIAL_ALE_MAPPING. +• *CONTACT_ERODING_NODES_TO_SURFACE contact may be used with SPH +particles. +INTRODUCTION +• Total Lagrangian SPH formulation 7 (*CONTROL_SPH) is now available in +MPP. +• The output formats for linear equation solver statistics now accommodate very +large numbers as seen in large models. +• *CONTROL_OUTPUT keyword parameter NPOPT is now applicable to thermal +data. If NPOPT = 1, then printing of the following input data to d3hsp is sup- +pressed: +◦ *INITIAL_TEMPERATURE +◦ *BOUNDARY_TEMPERATURE +◦ *BOUNDARY_FLUX +◦ *BOUNDARY_CONVECTION +◦ *BOUNDARY_RADIATION +◦ *BOUNDARY_ENCLOSURE_RADIATION +• Beam energy balance information is written to TPRINT file. +• MPP performance for LS-DYNA/Madymo coupling is improved. +• Shell adaptivity (*CONTROL_ADAPTIVE) is improved to reduce the number of +elements along curved surfaces in forming simulations. +• One-step unfolding +(*CONTROL_FORMING_ONESTEP) +is +improved +to +accommodate blanks with small initial holes. +• Efficiency of FORM 3 isogeometric shells is improved. +• The processing of *SET_xxx_GENERAL is faster. +• *KEYWORD_JOBID now works even when using the *CASE command. +• Parts may be repositioned in a small restart by including *DEFINE_TRANSFOR- +MATION and *NODE_TRANSFORM in the small restart deck to move nodes of +a specified node set prior to continuing the simulation. +Capabilities added during 2012/2013 to create LS-DYNA R7.0: +• Three solvers, EM, CESE, and ICFD, and a volume mesher to support the latter +two solvers, are new in Version 7. Brief descriptions of those solvers are given +below. Keyword commands for the new solvers are in Volume III of the LS- +DYNA Keyword User’s Manual. These new solvers are only included in double +precision executables. +• Keyword family: *EM_, the keywords starting with *EM refer to and control the +Electromagnetic solver problem set up: +◦ EM Solver Characteristics: + Implicit +INTRODUCTION + Double precision + Dynamic memory handling + SMP and MPP + 2D axisymmetric solver / 3D solver + Automatic coupling with structural and thermal LS-DYNA solvers + FEM for conducting pieces only, no air mesh needed (FEM-BEM sys- +tem) + Solid elements for conductors, shells can be insulators +◦ EM Solver Main Features: + Eddy Current (a.k.a Induction-Diffusion) solver + Induced heating solver + Resistive heating solver + Imposed tension or current circuits + Exterior field + Magnetic materials (beta version) + Electromagnetic contact + EM Equation of states (Conductivity as a function of temperature) +◦ EM Solver Applications (Non-exhaustive) : + Electromagnetic forming + Electromagnetic welding + Electromagnetic bending + Inductive heating + Resistive heating + Rail-gun + Ring expansions +• Keyword family: *CESE_, the keywords starting with *CESE refer to and control +the Compressible CFD solver problem set up: +◦ CESE Solver Characteristics: + Explicit + Double precision + Dynamic memory handling + SMP and MPP + 3D solver / special case 2D solver and 2D axisymmetric solver + Automatic coupling with structural and thermal LS-DYNA solvers + Eulerian fixed mesh or moving mesh (Either type input with *ELE- +MENT_SOLID cards or using *MESH cards) +◦ CESE Solver Main Features: +INTRODUCTION + The CESE (Conservation Element / Solution Element) method en- +forces conservation in space-time + Highly accurate shock wave capturing + Cavitation model + Embedded (immersed) boundary approach or moving (fitting) ap- +proach for FSI problems + Coupled stochastic fuel spray solver + Coupling with chemistry solver +◦ CESE Solver Applications (Non-exhaustive) : + Shock wave capturing + Shock/acoustic wave interaction + Cavitating flows + Conjugate heat transfer problems + Many different kinds of stochastic particle flows, e.g, dust, water, +fuel. + Chemically reacting flows, e.g, detonating flow, supersonic combus- +tion. +• Keyword family: *ICFD_, the keywords starting with *ICFD refer to and control +the incompressible CFD solver problem set up: +◦ ICFD Solver Characteristics: + Implicit + Double precision + Dynamic memory handling + SMP and MPP + 2D solver / 3D solver + Makes use of an automatic volume mesh generator for fluid domain + + Coupling with structural and thermal LS-DYNA solvers +◦ ICFD Solver Main Features: + Incompressible fluid solver + Thermal solver for fluids + Free Surface flows + Two-phase flows + Turbulence models + Transient or steady-state problems + Non-Newtonian fluids + Boussinesq model for convection + Loose or strong coupling for FSI (Fluid-structure interaction) + Exact boundary condition imposition for FSI problems +INTRODUCTION +◦ ICFD Solver Applications (Non-exhaustive) : + External aerodynamics for incompressible flows + Internal aerodynamics for incompressible flows + Sloshing, Slamming and Wave impacts + FSI problems + Conjugate heat transfer problems +• Keyword family: *MESH_, the keywords starting with *MESH refer to and +control the tools for the automatic volume mesh generator for the CESE and +ICFD solvers. +◦ Mesh Generator Characteristics: + Automatic + Robust + Generic + Tetrahedral elements for 3D, Triangles in 2D + Closed body fitted mesh (surface mesh) needs to be provided for vol- +ume generation +◦ Mesh Generator Main Features: + Automatic remeshing to keep acceptable mesh quality for FSI prob- +lems (ICFD only) + Adaptive meshing tools (ICFD only) + Anisotropic boundary layer mesh + Mesh element size control tools + Remeshing tools for surface meshes to ensure mesh quality +◦ Mesh Generator Applications : + Used by the Incompressible CFD solver (ICFD). + Used by the Compressible CFD solver (CESE). +Other additions to Version 7 include: +• Add new parameter VNTOPT to *AIRBAG_HYBRID, that allows user more +control on bag venting area calculation. +• Allow heat convection between environment and CPM bag (*AIRBAG_PARTI- +CLE) bag. Apply proper probability density function to part's temperature +created by the particle impact. +• *AIRBAG_PARTICLE and *SENSOR_SWITCH_SHELL_TO_VENT allows user +to input load curve to control the venting using choking flow equation to get +proper probability function for vents. Therefore, this vent will have the same +vent rate as real vent hole. +INTRODUCTION +• Add new option NP2P in *CONTROL_CPM to control the repartition frequency +of CPM particles among processors (MPP only). +• Enhance *AIRBAG_PARTICLE to support a negative friction factor (FRIC or +PFRIC) in particle to fabric contact. Particles are thus able to rebound at a trajec- +tory closer to the fabric surface after contact. +• Use heat convection coefficient HCONV and fabric thermal conductivity KP to +get correct effective heat transfer coefficient for heat loss calculation in +*AIRBAG_PARTICLE. If KP is not given, H will be used as effective heat trans- +fer coefficient. +• Extend CPM inflator orifice limit from 100 to unlimited (*AIRBAG_PARTICLE). +• Support dm_in_dt and dm_out_dt output to CPM chamber database (*DATA- +BASE_ABSTAT) to allow user to study mass flow rate between multiple cham- +bers. +• Previously, the number of ships (rigid bodies) in *BOUNDARY_MCOL, as +specified by NMCOL, was limited to 2. Apparently, this was because the code +had not been validated for more than 2 rigid bodies, but it is believed that it +should not be a problem to remove this restriction. Consequently, this limit has +been raised to 10, with the caveat that the user should verify the results for NM- +COL > 2. +a +• Implemented +structural-acoustic mapping +(*BOUNDARY_- +ACOUSTIC_MAPPING), for mapping transient structural nodal velocity to +acoustic volume surface nodes. This is useful if the structure finite element mesh +and the acoustic boundary/finite element mesh are mismatched. +scheme +• *CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURACE_ORTHO_FRIC- +TION can now be defined by part set IDs when supplemented by *DEFINE_- +FRICTION_ORIENTATION. Segment sets with orientation per *DEFINE_FRIC- +TION_ORIENTATION are generated automatically. +• Contact force of *CONTACT_ENTITY is now available in intfor (*DATABASE_- +BINARY_INTFOR). +• *CONTACT_FORCE_TRANSDUCER_PENALTY will now accept node sets for +both the slave and master sides, which should allow them to work correctly for +eroding materials. BOTH sides should use node sets, or neither. +• Added option to create a backup penalty-based contact for a tied constraint- +based contact in the input (IPBACK on Card E of *CONTACT). +• New option for *CONTACT_ENTITY. If variable SO is set to 2, then a con- +straint-like option is used to compute the forces in the normal direction. Friction +is treated in the usual way. +• *CONTACT_ENTITY: allow friction coefficient to be given by a “coefficient vs +time” load curve (input < 0 -> absolute value is the load curve ID). Also, if the +friction coefficient bigger or equal 1.0, the node sticks with no sliding at all. +INTRODUCTION +• Minor tweak to the way both MPP and SMP handle nodes sliding off the ends of +beams in *CONTACT_GUIDED_CABLE. +• Frictional energy output in sleout (*DATABASE_SLEOUT) supported for *CON- +TACT_…_MORTAR. +• Tiebreak damage parameter output as “contact gap” in intfor file for *CON- +OP- +TACT_AUTOMATIC_SURFACE_TO_SURFACE_TIEBREAK_MORTAR, +TION = 9. +• Added MPP support for *CONTACT_2D_AUTOMATIC_SINGLE_SURFACE +and *CONTACT_2D_AUTOMATIC_SURFACE_TO_SURFACE. +• Added keyword *CONSTRAINED_MULTIPLE_GLOBAL for defining multi- +node constraints for imposing periodic boundary conditions. +• Enhancement for *CONSTRAINED_INTERPOLATION_SPOTWELD (SPR3): +calculation of bending moment is more accurate now. +• If *CONSTRAINED_NODAL_RIGID_BODY nodes are shared by several +processors with mass scaling on, the added mass is not summed up across +processors. This results in an instability of the NRB. (MPP only) +• *ALE_REFINE has been replaced and expanded upon by the *CONTROL_RE- +FINE family of commands. These commands invoke local mesh refinement of +shells, solids, and ALE elements based on various criteria. +• Shells or solids in a region selected for refinement (parent element) are replaced +by 4 shells or 8 solids, respectively. *CONTROL_REFINE_SHELL applies to +shells, *CONTROL_REFINE_SOLID applies to solids and *CONTROL_RE- +FINE_ALE and *CONTROL_REFINE_ALE2D applies to ALE elements. Each +keyword has up to 3 lines of input. If only the 1st card is defined, the refinement +occurs during the initialization. The 2nd card defines a criterion CRITRF to +automatically refine the elements during the run. If the 3rd card is defined, the +refinement can be reversed based on a criterion CRITM. All commands are +implemented for MPP. +• *CONTROL_REFINE_MPP_DISTRIBUTION distributes the elements required +by the refinement across the MPP processes. +• Eliminate automatic writing of a d3plot plot state after each 3D tetrahedral +remeshing operation (*CONTROL_REMESHING) to reduce volume of output. +• Generate disbout output (*DATABASE_DISBOUT) for MPP and SMP binout +files. +• Extend *DATABASE_MASSOUT to include option to output mass information +on rigid body nodes. +• Added new keyword *CHANGE_OUTPUT for full deck restart to override +default behavior of overwriting existing ASCII files. For small restart, this option +INTRODUCTION +has no effect since all ASCII output is appended to the result of previous run +already. +• Added new option (NEWLENGD) to 2nd field of 3rd card of *CONTROL_OUT- +PUT to write more detailed legend in ASCII output files. At present, only rcforc +and jntforc are implemented. +• Increased default binary file size scale factor (x=) from 7 to 1024. That means the +default binary file size will be 1 Gb for single version and 2 Gb for double ver- +sion. +• Add echo of new “max frequency of element failure summaries” flag (FRFREQ +in *CONTROL_OUTPUT) to d3hsp file. +• Support LSDA/binout output for new pllyout file (*DATABASE_PLLYOUT, +*ELEMENT_BEAM_PULLEY) in both SMP and MPP. +• Allow degenerated hexahedrons +for cohesive solid elements +(ELFORM = 19, 20) that evolve from an extrusion of triangular shells. The input +of nodes on the element cards for such a pentahedron is given by: N1, N2, N3, +N3, N4, N5, N6, N6. +(pentas) +• Add new option to activate drilling constraint force for shells in explicit +calculations. This can be defined by parameters DRCPSID (part set) and DR- +CPRM (scaling factor) on *CONTROL_SHELL. +• Add SMP ASCII database “pllyout” (*DATABASE_PLLYOUT) for *ELEMENT_- +BEAM_PULLEY. +• *FREQUENCY_DOMAIN_ACOUSTIC_BEM: +◦ Added an option to output real part of acoustic pressure in time domain. +◦ Enabled BEM acoustic computation following implicit transient analysis. +◦ Implemented coupling between steady state dynamics and collocation +acoustic BEM. +◦ Implemented Acoustic Transfer Vector (ATV) to variational indirect BEM +acoustics. +◦ Enabled boundary acoustic mapping in BEM acoustics. +• *FREQUENCY_DOMAIN_ACOUSTIC_FEM: +◦ Added boundary nodal velocity to binary plot file d3acs. +◦ Implemented pentahedron elements in FEM acoustics. +◦ Enabled using boundary acoustic mapping in FEM acoustics. +• *FREQUENCY_DOMAIN_FRF: +◦ Updated FRF to include output in all directions (VAD2 = 4). +◦ Added treatment for FRF with base acceleration (node id can be 0). +INTRODUCTION +• *FREQUENCY_DOMAIN_RANDOM_VIBRATION: +◦ Updated calculation of PSD and RMS von Mises stress in random vibration +environment, based on Sandia National Laboratories report, 1998. +• *FREQUENCY_DOMAIN_RANDOM_VIBRATION_FATIGUE: +◦ Implemented an option to incorporate initial damage ratio in random vi- +bration fatigue. +• *FREQUENCY_DOMAIN_RESPONSE_SPECTRUM: +◦ Implemented double sum methods (based on Gupta-Cordero coefficient, +modified Gupta-Cordero coefficient, and Rosenblueth-Elorduy coefficient). +◦ Updated calculating von Mises stress in response spectrum analysis. +◦ Implemented treatment for multi simultaneous input spectra. +◦ Improved double sum methods by reducing number of loops. +• *FREQUENCY_DOMAIN_SSD: +◦ Added the option to output real and imaginary parts of frequency re- +sponse to d3ssd. +◦ Added the option to output relative displacement, velocity and accelera- +tion in SSD computation in the case of base acceleration. Previously only +absolute values were provided. +• Implemented keyword *FREQUENCY_DOMAIN_MODE_{OPTION} so that +user can select the vibration modes to be used for frequency response analysis. +• Implemented keyword *SET_MODE_{OPTION} so that user can define a set of +vibration modes, to be used for frequency response analysis. +• Implemented keyword *FREQUENCY_DOMAIN_PATH to define the path of +binary databases containing mode information, used in restarting frequency +domain analysis, e.g. frf, ssd, random vibration. +• Compute normal component of impulse for oblique plates in *INITIAL_MINE_- +IMPULSE. The feature is no longer limited to horizontal plates. +• Disable license security for *INITIAL_IMPULSE_MINE. The feature is no longer +restricted. +• Enabled hourglass type 7 to work well with *INITIAL_FOAM_REFERENCE_- +GEOMETRY so that initial hourglass energy is properly calculated and foam will +spring back to the initial geometry. +• Accommodate erosion of thin shells in *LOAD_BLAST_ENHANCHED. +INTRODUCTION +• *LOAD_VOLUME_LOSS has been changed such that after the analysis time +exceeds the last point on the curve of volume change fraction versus time, the +volume change is no longer enforced. +• *LOAD_BODY_POROUS new option AOPT added to assign porosity values in +material coordinate system. +• Added *LOAD_SEGMENT_FILE. +• Add new sensor definition, *SENSOR_DEFINE_ANGLE. This card traces the +angle formed between two lines. +• *SENSOR_DEFINE_NODE can be used to trace the magnitude of nodal values +(coordinate, velocity or accleration) when VID is “0” or undefined. +• Add two new parameters to *SENSOR_DEFINE_ELEMENT, scale factor and +power, so that user can adjust the element-based sensor values (strain, stress, +force, …). +• Change history variables 10-12 in *MAT_054/*MAT_ENHANCED_COMPOS- +ITE_DAMAGE (thin shells only) to represent strains in material coordinate +system rather than in local element coordinate system. This is a lot more helpful +for postprocessing issues. This change should not lead to different results other +than due to different round-off errors. +• New features and enhancements to *MAT_244/*_MAT_UHS_STEEL: +◦ Added implicit support for MAT_244. +◦ Changed the influence of the austenite grain size in Mat244 according to Li +et al. +◦ Changed the start temperatures to fully follow WATT et al and Li et al. +◦ Hardness calculation is now improved when noncontinuous cooling is ap- +plied i.e., tempering. +◦ Added temperature dependent Poisson ratio and advanced reaction kinet- +ics. +◦ Added new advanced option to describe the thermal expansion coeffi- +cients for each phase. +◦ Added option to use Curve ID or a Table ID for describing the latent heat +generation during phase transormations. +◦ Added support for table definition for Youngs modulus. Now you can +have one temperature dependent curve for each of the 5 phases +• Added support for implicit to *MAT_188. +• Added material model *MAT_273/*MAT_CDPM/*MAT_CONCRETE_DAM- +AGE_PLASTIC_MODEL. This model is aimed at simulations where failure of +concrete structures subjected to dynamic loadings is sought. The model is based +on effective stress plasticity and has a damage model based on both plastic and +elastic strain measures. Implemented for solids only but both for explicit and +INTRODUCTION +implicit simulations. Using an implicit solution when damage is activated may +trigger a slow convergense. IMFLAG = 4 or 5 can be useful. +• Added an option in *MAT_266 (*MAT_TISSUE_DISPERSED) so that the user can +tailor the active contribution with a time dependent load curve instead of using +the internal hardcoded option. See ACT10 in the User's Manual. +• *MAT_173/*MAT_MOHR_COULOMB is available in 2D. +• Enable *MAT_103 and *MAT_104 to discretize the material load curves accord- +ing to the number of points specified by LCINT in *CONTROL_SOLUTION. +• Implement Prony series up to 18 terms for shells using *MAT_076/*MAT_GEN- +ERAL_VISCOELASTIC. +• Added *DEFINE_STOCHASTIC_VARIATION and the STOCHASTIC option for +*MATs 10, 15, 24, 81, 98 for shells, solids, and type 13 tets. This feature defines a +stochastic variation in the yield stress and damage/failure of the aforementioned +material models. +• Add Moodification for *DEFINE_CONNECTION_PROPERTIES, PROPRUL = 2: +thinner weld partner is first partner, PROPRUL = 3: bottom (nodes 1-2-3-4) weld +partner is first partner. +• Add spotweld area to debug output of *DEFINE_CONNECTION_PROPERTIES +which is activated by *CONTROL_DEBUG. +• Add support of *MAT_ADD_EROSION option NUMFIP < 0 for standard (non- +GISSMO) failure criteria. Only for shells. +• Improve implicit convergence of *MAT_ADD_EROSION damage model GISS- +MO by adding damage scaling (1-D) to the tangent stiffness matrix. +• Provide plastic strain rates (tension/compression, shear, biaxial) as history +variables no. 16, 17, and 18 for *MAT_187. +• Add new variables to user failure routine matusr_24 (activated by FAIL < 0 on +*MAT_024 and other materials): integration point numbers and element id. +• Add new energy based, nonlocal failure criterion for *MAT_ADD_EROSION, +parameters ENGCRT (critical energy) and RADCRT (critical radius) after EP- +STHIN. Total internal energy of elements within a radius RADCRT must exceed +ENGCRT for erosion to occur. Intended for windshield impact. +• Add new option to *MAT_054 for thin shells: Load curves for rate dependent +strengths and a rate averaging flag can be defined on new optional card 9. +• Add new option for *MAT_MUSCLE: Input parameter SSP < 0 can now refer to a +load curve (stress vs. stretch ratio) or a table (stress vs. stretch ratio vs. normal- +ized strain rate). +• Expand list of variables for *MAT_USER_DEFINED_MATERIAL_MODELS by +characteristic element size and element id. +INTRODUCTION +• Enable +*MAT_USER_DEFINED_MATERIAL_MODELS +tetrahedron element type 13. +“umat41v_t13” show corresponding pressure calculation in the elastic case. +to be used with + New sample routines “umat41_t13” and +• Add a new feature to *MAT_125 allowing C1 and C2 to be used in calculation of +back stress. When plastic strain < 0.5%, C1 is used, otherwise C2 is used as +described in Yoshida's paper. +• Extend non-linear strain path (_NLP_FAILURE) in *MAT_037 to implicit. +• *MAT_173/*MAT_MOHR_COULOMB now works in ALE. A new option has +been added to suppress the tensile limit on hydrostatic stress recommended for +ALE multi-material use. +• Upgraded *MAT_172/*MAT_CONCRETE_EC2. +◦ Corrections to DEGRAD option. +◦ Concrete and reinforcement types 7 and 8 have been added to reflect +changes to Eurocode 2. +◦ Extra history variables for reinforcement stress and strain are now output +as zero for zero-fraction reinforcement directions. +• Added RCDC model for solid *MAT_082. +• Added Feng's failure model to solid *MAT_021. +• Added *MAT_027 for beams. +• Added *DEFINE_HAZ_PROPERTIES and *DEFINE_HAZ_TAILOR_WELDED_- +BLANK for modifying material behavior near a spot weld. +• Added fourth rate form to viscoplastic Johnson-Cook model (*MAT_015). +• Added option to *MAT_224 to not delete the element if NUMINT = -200. +• New damage initiation option 3 in multi fold damage criteria in *MAT_ADD_- +EROSION. Very similar to option 2 but insensitive to pressure. +• Added rotational resistance in *MAT_034/*MAT_FABRIC. Optionally the user +may specify the stiffness, yield and thickness of and elastic-perfectly-plastic +coated layer of a fabric that results in a rotational resistance during the simula- +tion. +• FLDNIPF < 0 in *MAT_190/*MAT_FLD_3-PARAMETER_BARLAT for shell +elements means that failure occurs when all integration points within a relative +distance of -FLDNIPF from the mid surface has reached the fld criterion. +• A computational welding mechanics *MAT_270/*MAT_CWM material is +available that allows for element birth based on a birth temperature as well as +annealing based on an annealing temperature. The material is in addition a +thermo-elasto-plastic material with kinematic hardening and temperature de- +pendent properties. +INTRODUCTION +• Added *MAT_271/*MAT_POWDER, a material +(i.e., +compaction and sintering) of cemented carbides. It is divided into an elastic- +plastic compaction model that is supposed to be run in a first phase, and a visco- +elastic sintering model that should be run in a second phase. This model is for +solid elements. +for manufacturing +• For IHYPER = 3 on a *MAT_USER_DEFINED_… shell material, the deformation +gradient is calculated from the geometry instead of incremented by the velocity +gradient. The deformation gradient is also passed to the user defined subrou- +tines in the global system together with a transformation matrix between the +global and material frames. This allows for freedom in how to deal with the +deformation gradient and its transformations in orthotropic (layered) materials. +• The Bergstrom-Boyce viscoelastic rubber model is now available in explicit and +implicit analysis as *MAT_269/*MAT_BERGSTROM_BOYCE_RUBBER. The +Arruda-Boyce elastic stress is augmented with a Bergstrom-Boyce viscoelastic +stress corresponding to the response of a single entangled chain in a polymer gel +matrix. +• Added a new parameter IEVTS to *MAT_USER_DEFINED_MATERIAL_MOD- +ELS (*MAT_041-050). IEVTS is optional and is used only by thick shell formula- +tion 5. It points to the position of E(a) in the material constants array. Following +E(a), the next 5 material constants must be E(b), E(c), v(ba), v(ca), and v(cb). This +data enables thick shell formulation 5 to calculate an accurate thickness strain, +otherwise the thickness strain will be based on the elastic constants pointed to by +IBULK and IG. +• Implemented enhancements to fabric material (*MAT_034), FORM = 14. Stress- +strain curves may include a portion for fibers in compression. When un- +load/reload curves with negative curve ID are input (curve stretch options), the +code that finds the intersection point now extrapolates the curves at their end +rather than simply printing an error message if an intersection point cannot be +found before the last point in either curve. +• Map 1D to 3D by beam-volume averaging the 1D data over the 3D elements +(*INITIAL_ALE_MAPPING). +• In a 3D to 3D mapping (*INITIAL_ALE_MAPPING), map the relative displace- +ments for the penalty coupling in *CONSTRAINED_LAGRANGE_IN_SOLID. +• The [name].xy files associated with *DATABASE_ALE_MAT are now created +when sense switches sw1, sw2, quit, or stop are issued. +• *ALE_ESSENTIAL_BOUNDARY is available in 2D. +• *DATABASE_FSI is available for 2D (MPP). +• *ALE_ESSENTIAL_BOUNDARY implemented to apply slip-only velocity BC +along ALE mesh surface. +INTRODUCTION +• *CONTROL_ALE flag INIJWL = 2 option added to balance initial pressure state +between ALE Soil and HE. +• Include SPH element (*ELEMENT_SPH) in time step report. +• Time step and internal energy of 2D axisymmetric SPH elements are calculated +in a new way more consistent with the viscosity force calculation. +• Only apply viscosity force to x and y components of 2D axisymmetric SPH +element, not on hoop component. +• MAXV in *CONTROL_SPH can be defined as a negative number to turn off +velocity checking. +• Improve calculation of 2D axisymmetric SPH contact force in *DEFINE_SPH_- +TO_SPH_COUPLING. +• Added the following material models for SPH particles: *MAT_004/*MAT_- +ELASTIC_PLASTIC_THERMAL (3D only) and *MAT_106/*MAT_ELASTIC_- +VISCOPLASTIC_THERMAL +• Added a new parameter DFACT for *DEFINE_SPH_TO_SPH_COUPLING. +DFACT invokes a viscous term to damp the coupling between two SPH parts +and thereby reduce the relative velocity between the parts. +• Added BOUNDARY_CONVECTION and BOUNDARY_RADIATION +for +explicit SPH thermal solver. +• *CONTROL_REMESHING_EFG: +◦ Add eroding failed surface elements and reconstructing surface in EFG +adaptivity. +◦ Add a control parameter for monotonic mesh resizing in EFG adaptivity. +◦ Add searching and correcting self-penetration for adaptive parts in 3D tet- +rahedron remeshing. +• Enhance 3D axisymmetric remeshing with 6-node/8-node elements +• (*CONTROL_REMESHING): +◦ Use RMIN/RMAX along with SEGANG to determine element size. +◦ Remove the restriction that the reference point of computational model has +to be at original point (0, 0, 0). +◦ Rewrite the searching algorithm for identifying the feature lines of cross- +sections in order to provide more stable remeshing results. +• Improve rigid body motion in EFG shell type 41. +• Support EFG pressure smoothing in EFG solid type 42 for *MAT_ELASTIC_VIS- +COPLASTIC_THERMAL. +• Add visco effect for implicit EFG solid type 42. +INTRODUCTION +• Add new EFG solid type 43 (called Meshfree-Enriched FEM, MEFEM) for both +implicit and explicit. This element formulation is able to relieve the volumetric +locking for nearly-incompressible material (eg. rubber) and performs strain +smoothing across elements with common faces. +• EFG shell adaptivity no longer requires a special license. +• Application of EFG in an implicit analysis no longer requires a special license. +• Add *SENSOR_CONTROL for prescribed motion constraints in implicit. +• Update *INTERFACE_LINKING_NODE in implicit to catch up with explicit, +including adding scaling factors. +• Add support for *DATABASE_RCFORC_MOMENT for implicit. +• Enhance Iterative solvers for Implicit Mechanics. +• Add, after the first implicit time step, the output of projected cpu and wall clock +times. This was already in place for explicit. Also echo the termination time. +• Add variable MXDMP in *CONTROL_THERMAL_SOLVER to write thermal +conductance matrix and right-hand side every MXDMP time steps. +• Add keyword *CONTROL_THERMAL_EIGENVALUE to calculate eigenval- +ue(s) of each thermal conductance matrix. +• Added thermal material model *MAT_THERMAL_ORTHOTROPIC_TD_LC. +This is an orthtropic material with temperature dependent properties defined by +load curves. +• Changed structured file format for control card 27 (first thermal control card). +Several input variables used i5 format limiting their value to 99,999. A recent +large model exceeded this limit. The format was changed to i10. This change is +not backward compatible. Old structured input files will no longer run unless +control card 27 is changed to the new i10 format. This change does not affect the +KEYWORD file. +• Add +thermal material *MAT_T07/*MAT_THERMAL_CWM +for welding +simulations, to be used in conjunction with mechanical counterpart *MAT_- +270/*MAT_CWM. +• Modify decomposition costs of *MAT_181 and *MAT_183. +• Introduce new timing routines and summary at termination. +• Echo “MPP contact is groupable” flag to d3hsp +• Bodies using *MAT_RIGID_DISCRETE were never expected to share nodes with +non-rigid bodies, but this now works in MPP. +• There is no longer any built-in limitation on the number of processors that may +be used in MPP. +INTRODUCTION +• Echo contents of the MPP pfile (including keyword additions) to the d3hsp and +mes0000 files. +• Add new keyword *CONTROL_MPP_PFILE, which allows for insertion of text +following this command to be inserted into the MPP pfile (p = pfile). +• Change in MPP treatment of *CONSTRAINED_TIE-BREAK. They now share a +single MPI communicator, and a single round of communication. This should +improve performance for problems with large numbers of these, without affect- +ing the results. +• Added two input variables for *CONTROL_FORMING_ONESTEP simulation, +TSCLMIN is a scale factor limiting the thickness reduction and EPSMAX defines +the maximum plastic strain allowed. +• Added output of strain and stress tensors for onestep solver *CONTROL_FORM- +ING_ONESTEP, to allow better evaluation of formability. +• Improved *CONTACT_AUTO_MOVE: before changes the termination time, and +it causes problems when several tools need to be moved. Now *CONTACT_AU- +TO_MOVE does not change the termination time, but changes the current time. +In this way, several tools can be moved without the need to worry about the +other tool's move. This is especially useful in multi-flanging and hemming +simulations. +• Made improvements to previously undocumented keyword *INTERFACE_- +BLANKSIZE, including adding the options_INITIAL_TRIM, and_INITIAL_- +ADAPTIVE. This keyword was developed for blank size development in sheet +metal forming. Generally, for a single forming process, only the option_DEVEL- +OPMENT is needed and inputs are an initial estimated blank shape, a formed +blank shape, and a target blank shape in either mesh or boundary coordinates. +Output will be the calculated/corrected initial blank shape. Initial blank mesh +and formed blank mesh can be different (e.g. adaptive). For a multi-stamping +process involving draw, trimming and flanging, all three options are needed. +Related commands for blank size estimation are *CONTROL_FORMING_ON- +ESTEP, and for trim line development, *CONTROL_FORMING_UNFLANGING. +• Made improvements and added features to previously undocumented keyword +*CONTROL_FORMING_UNFLANGING, this keyword unfolds flanges of a +deformable blank, e.g., flanged or hemmed portions of a sheet metal part, onto a +rigid tooling mesh using the implicit static solver. It is typically used in trim line +mapping during a draw die development process. The roots of the flanges or +hemmed edges are automatically processed based on a user input of a distance +tolerance between the flanges/hemmed edges and rigid tool. It includes the +ability to handle a vertical flange wall. Other keywords related to blank size +development are, *CONTROL_FORMING_ONESTEP, and *INTERFACE_- +BLANKSIZE_DEVELOPMENT. +INTRODUCTION +• Added keyword *CONTROL_FORMING_OUTPUT which allows control of +d3plot output by specifying distances to tooling home. It works with automatic +position of stamping tools using *CONTROL_FORMING_AUTOPOSITION_PA- +RAMETER. +• Added the LOCAL_SMOOTH option to *INTERFACE_COMPENSATION_NEW +which features smoothing of a tool's local area mesh, which could otherwise +become distorted due to, e.g., bad/coarse mesh of the original tool surface, +tooling pairs (for example, flanging post and flanging steel) do not maintain a +constant gap and several compensation iterations. This new option also allows +for multiple regions to be smoothed. Local areas are defined by *SET_LIST_- +NODE_SMOOTH. +• Added output to rcforc for *DEFINE_DE_TO_SURFACE_COUPLING. +• Implement traction surface for *DEFINE_DE_TO_SURFACE_COUPLING. +• Add keyword *DATABASE_BINARY_DEMFOR with command line option +dem = dem_int_force. This will turn on the DEM interface force file for DEM +coupling option. The output frequency is controlled by the new keyword. +• Add new feature *DEFINE_DE_INJECTION to allow DEM particle dropping +from user defined plane. +• Add new option_VOLUME to *ELEMENT_DISCRETE_SPHERE. This will allow +DEM input based on per unit density and use *MAT card to get consistent +material properties. +• Added FORM = -4 for *ELEMENT_SHELL_NURBS_PATCH. Rotational dofs +are automatically set at control points at the patch boundaries, whereas in the +interior of the patch only translational dofs are present. This helps for joining +multiple nurbs patches at their C0-boundaries. +• Disabled FORM = 2 and 3 for *ELEMENT_SHELL_NURBS_PATCH. These +formulations are experimental and not fully validated yet. +• Added energy computation for isogeometric shells (*ELEMENT_SHELL_- +NURBS_PATCH) to matsum. +• Allow isogeometric shells (*ELEMENT_SHELL_NURBS_PATCH) to behave as +rigid body (*MAT_RIGID). +• Added “g” as abbreviation for gigawords in specification of memory on +execution line, e.g, memory = 16g is 16 billion words. +• Suppress non-printing characters in *COMMENT output. +• Add command line option “pgpkey” to output the current public PGP key used +by LS-DYNA. The output goes to the screen as well as a file named “lstc_ +pgpkey.asc” suitable for directly importing into GPG. +INTRODUCTION +• When reading the NAMES file, allow a “+” anywhere on a line to indicate there +will be a following line, not just at the end. This was never intended, but worked +before r73972 and some customers use it that way. +• Check for integer overflow when processing command line arguments and the +memory value on the *KEYWORD card. +• Added new capability for *INTERFACE_LINKING_NODE to scale the dis- +placements of the moving interface. +• Support for *KEYWORD_JOBID with internal *CASE driver. +• *DAMPING_FREQUENCY_RANGE now works for implicit dynamic solutions. +An error check has been added to ensure that the timestep is small enough for +the damping card to work correctly. +• Added new option *DAMPING_FREQUENCY_RANGE_DEFORM to damp +only the deformation instead of the global motion. +• Added *DEFINE_VECTOR_NODES. A vector is defined using two node IDs. +• Add sense switch “prof” to output current timing profile to message (SMP) file +or mes#### (MPP) files. Also, for MPP only, collect timing information from +processor and output to prof.out when sense switch “prof” is detected. +Capabilities added during 2013/2014 to create LS-DYNA R7.1: +• Add MUTABLE option for *PARAMETER so that parameter values can be +redefined later in the input deck. +• Change MPP treatment of two-sided *CONTACT_FORCE_TRANSDUCER so +that proper mass and moment values can be output to the rcforc file. +• MPP support for non-zero birthtime for *CONTACT_SINGLE_EDGE. +• Add new command line option “ldir=” for setting a local working directory. In +MPP, this has the same effect as setting the “directory { local }” pfile option (and +it overrides that option). For SMP, it indicates a directory where local, working +files should be placed. +• Add support for SMOOTH option in MPP groupable contact. +• Add new keyword card *CONTROL_REQUIRE_REVISION to prevent the +model from being run in old versions of LS-DYNA. +• Add part set specification for dynamic relaxation with implicit using *CON- +TROL_DYNAMIC_RELAXATION. + This is a new feature specified with +idrflg = 6 on *CONTROL_DYNAMIC_RELAXATION. This allows implicit to be +used for the dynamic relaxation phase for models involving parts being modeled +with SPH and/or ALE while excluding those parts from the dynamic relaxation +phase. +INTRODUCTION +• Add new feature for implicit automatic time step control to cooperate with +thermal time step control. On *CONTROL_IMPLICIT_AUTO, IAUTO = 2 is the +same as IAUTO = 1 with the extension that the implicit mechanical time step is +limited by the active thermal time step. +• On *CONTROL_IMPLICIT_SOLUTION, add negative value of MAXREF for +implicit mechanics. Nonlinear iteration will terminate after |MAXREF| itera- +tions. With MAXREF < 0 convergence is declared with a warning. Simulation +will continue. Positive values of MAXREF still cause failure of convergence to be +declared leading to either a time step reduction or an error termination. +• Add *CONTROL_IMPLICIT_MODAL_DYNAMIC keywords and features. This +elevates the modal dynamic features of IMASS = 2 on *CONTROL_IMPLICIT_- +DYNAMICS. It also adds additional features of damping and mode selection +and stress computations. +• New material model *MAT_DRY_FABRIC / MAT_214, which can be used in +modeling high strength woven fabrics with transverse orthotropic behavior. +• Add *ALE_COUPLING_NODAL_PENALTY, penalty-based nodal coupling +with ALE. +• Add type 8 *ELEMENT_SEATBELT_PRETENSIONER which takes energy-time +curve, instead of pull-in or force curve. +• Add type 9 *ELEMENT_SEATBELT_PRETENSIONER for energy-based buckle / +anchor pretensioner. +• Add *DATABASE_BINARY_FSILNK. This feature stores coupling pressure +from *CONSTRAINED_LAGRANGE_IN_SOLID in a binary time history file for +use in a separate model that does not include ALE. +• Add *LOAD_SEGMENT_FSILNK. Use pressure loads stored in aforementioned +binary time history file to load model that does not have ALE elements. +• Add new keyword *DEFINE_SPH_DE_COUPLING to allow SPH particles to +contact discrete element spheres (DES). +• Add MOISTURE option to *MAT_076 solids. Allows moisture content to be +input as a function of time. Material parameters are then scaled according to the +moisture and a moisture strain is also introduced. +• Add *RIGIDWALL_FORCE_TRANSDUCER to output forces from rigidwalls +acting on node sets. +• Add LOG_INTERPOLATION option to *MAT_024. This offers an alternate +means of invoking logarithmic interpolation for strain rate effects. The other +way is to input the natural log of strain rate in the table LCSS. +• Add capability in *MAT_ADD_EROSION (NUMFIP < -100) to set stress to zero +in each shell integration point as it reaches the failure criterion. When +|NUMFIP|-100 integration points have failed, the shell is eroded. In contrast, +INTRODUCTION +when NUMFIP > 0, failed integration points continue to carry full load as though +they were unfailed until element erosion occurs. +• Add new keyword, *PARAMETER_TYPE, for use by LS-PrePost when combin- +ing keyword input files. The appropriate offset is applied to each ID value +defined using *PARAMETER_TYPE, according to how that ID is used. +• Allow use of load curve to specify damping as a function of time in *DAMP- +ING_RELATIVE. +• Add a segment based (SOFT = 2) contact option to include the overlap area in the +contact stiffness calculation. This is good for improving the friction calculation +and possibly for implicit convergence. The option is turned on by setting +FNLSCL > 0 and DNLSCL = 0. As DNLSCL = 0, the contact stiffness is not +nonlinear. This new option is also useful when used with another improvement +that was made to the FS = 2 friction coefficient by table lookup option in segment +based contact. When the above mentioned FNLSCL > 0, option is used, the +FS = 2 option is now very accurate. +• Add a new RCDC damage option, *MAT_PLASTICITY_WITH_DAMAGE_OR- +THO_RCDC1980 which is consistent with the WILKINS paper. It uses the +principal values of stress deviators and a different expression for the A_d term. +• Add a TIETYP option to *CONTACT_2D_AUTOMATIC. By default the tied +contact automatically uses constraint equations when possible for 2D tied con- +tact. If a conflict is detected with other constraints, or to avoid 2-way constraints, +penalty type ties are used when constraints are not possible. The TIETYP option, +when set to 1, causes all ties to use the penalty method. This is useful if in spite +of the code's best efforts to avoid problems, there is still a conflict in the model. +• Add a scale factor for scaling the frictional stiffness for contact. The parameter is +FRICSF on optional card E and it's only supported for segment based (SOFT = 2) +contact. This was motivated by a rubber vs. road skidding problem where the +friction coefficent had static, dynamic and decay parameters defined. The +growth of the frictional force was too slow so the static coulomb value could not +be achieved. By scaling the frictional stiffness higher, the coulomb value could +approach the static value. +• Add keyword *CONTACT_2D_AUTOMATIC_FORCE_TRANSDUCER. Like +the 3D force transducers, it does no contact calculation but only measures the +contact forces from other contact definitions. When only a slave side is defined, +the contact force on those segments is measured. Currently, two surface force +transducers are not available. +• Add options to *MAT_058: +◦ Load curves for rate dependent strain values (E11C, E11T, …) can be de- +fined on new optional card 9. +INTRODUCTION +◦ Load curves for rate dependent strengths (XC, XT, …) and a rate averaging +flag can be defined on new optional card 8. +◦ Abscissa values in above curves are taken to be natural log of strain rate +when the first value is negative. +◦ Add optional transverse shear damage to *MAT_058. +• Add MAT_261 and MAT_262 for general use. *MAT_261 is *MAT_LAMINA- + *MAT_262 is *MAT_LAMINATED_ +TED_FRACTURE_DAIMLER_PINHO. +FRACTURE_DAIMLER_CAMANHO. +• Add pentahedra cohesive solid element types (TYPE = 21 & 22). Type = 21 is the +pentahedra version of Type = 19 and Type = 22 is the pentahedra version of +Type = 20. Using ESORT.gt.0 in *CONTROL_SOLID will automatically sort out +the pentahedra elements (19 to 21 and 20 to 22). +• Add *DEFINE_DE_BY_PART to define control parameters for DES by part ID, +including damping coefficient, friction coefficient, spring constant, etc. If de- +fined, it will overwrite the parameters in *CONTROL_DISCRETE_ELEMENT. +• Add new feature for *MAT_030 (*MAT_SHAPE_MEMORY) as optional 3rd card. +Curves or tables (strain rate dependency) can be defined to describe plastic +loading and unloading behavior. +• New feature for *ELEMENT_BEAM_PULLEY. Beam elements BID1 and BID2 +can now both be defined as “0” (zero). In that case, adjacent beam elements are +automatically detected. Therefore, the first two beam elements with nodal +distance < 1.0e-6 to the pulley node (PNID) will be chosen. +• Add new feature to *MAT_ADD_EROSION's damage model GISSMO. By +default, damage is driven by equivalent plastic strain. Now, users can optionally +define another history variable as driving quantity by setting DMGTYP. +• Add volumetric plastic strain to *MAT_187 as history variable 6. +• Add internal energy calculation for *ELEMENT_BEAM_PULLEY. +• Add viscoplastic option to *MAT_157: new parameter VP on Card 5, Column 6. +• Add new keyword *MAT_ADD_COHESIVE which is intended to make 3D +material models available for cohesive elements. +• Add new parameters to *MAT_CABLE_DISCRETE / *MAT_071. MXEPS (Card +2, Column 4) is equal the maximum strain at failure and MXFRC (Card 2, Col- +umn 5) is equal to the maximum force at failure +• Add *MAT_124 as potential weld partner material for PROPRUL = 2/3 of *DE- +FINE_CONNECTION_PROPERTIES. +• Add new material *MAT_TOUGHENED_ADHESIVE_POLYMER (TAPO) or +*MAT_252 for epoxy-based, toughened, ductile adhesives. +INTRODUCTION +• Add new option to *MAT_002_ANIS: parameter IHIS on Card 4, Column 8. +IHIS = 0: terms C11, C12, … from Cards 1, 2, and 3 are used. IHIS = 1: terms C11, +C12, … initialized by *INITIAL_STRESS_SOLID's extra history variables. +• Add new option to *MAT_102. Instead of constant activation energy Q, one can +define a load curve LCQ on Card 2, Column 7: +◦ LCQ.GT.0: Q as function of plastic strain +◦ LCQ.LT.0: Q as function of temperature +• Add new option to *MAT_071 (MAT_CABLE_DISCRETE_BEAM). + New +parameter FRACL0 (Card 2, Column 3) is fraction of initial length that should be +reached over time period of TRAMP. That means the cable element length gets +modified from L0 to FRACL0*L0 between t = 0 and t = TRAMP. +• Add internal energy calculation for SPR models *CONSTRAINED_INTERPOLA- +TION_SPOTWELD (SPR3) and *CONSTRAINED_SPR2. Their contribution was +missing in energy reports like glstat. +• Add new failure model OPT = 11 to *MAT_SPOTWELD/*MAT_100 for beam +elements. +• Add three new failure criteria for shell elements to *MAT_ADD_EROSION on +optional card 4, columns 6-8: +◦ LCEPS12: load curve in-plane shear strain limit vs. element size. +◦ LCEPS13: load curve cross-thickness shear strain limit vs. element size. +◦ LCEPSMX: load curve in-plane major strain limit vs. element size. +• Add new capability to *MAT_ADD_EROSION damage model GISSMO. Strain +rate scaling curve LCSRS can now contain natural logarithm values of strain +rates as abscissa values. This is automatically assumed when the first value is +negative. +• Add new parameter NHMOD to *MAT_266. The constitutive model for the +isotropic part can now be chosen: +◦ NHMOD = 0: original implementation (modified Neo-Hooke) +◦ NHMOD = 1: standard Neo-Hookeon (as in umat45) +• New keyword *DEFINE_TABLE_MATRIX is an alternative way of defining a +table and the curves that the table references from a single unformatted text file, +e.g., as saved from an Excel spreadsheet. +• Change long format so that all data fields are 20 columns and each line of input +can hold up to 200 columns. In this way, the number of input lines is the same +for long format as for standard format. +◦ 8 variables per line in long format = 160 columns +INTRODUCTION +◦ 10 variables per line in long format = 200 columns +• Add a new option (SOFT = 6) in *CONTACT_FORMING_NODES_TO_SUR- +FACE for blank edge and guide pin contact. +• Add user-defined criteria for mesh refinement (or coarsening) in *CONTROL_- +REFINE_…. +• Add new contact option that currently only works for MPP SINGLE_SURFACE +contact with SOFT = 0 or 1. If SRNDE (field 4 of optional card E) is a 1, then free +edges of the contact definition will be rounded WITHOUT extending the seg- +ments. Rather than having cylindrical caps on the ends of the segments, the +“corners” of the squared off thickness are rounded over. +• Add geometric contact entity type -3 “finite cylinder”. +• Add irate = 2 to *CONTROL_IMPLICIT_DYNAMICS to turn off rate effects for +both implicit and explicit. +• Add quadratic 8-node and 6-node shells (shell formulations 23 and 24). +• Add LOG_LOG_INTERPOLATION option for table defining strain rate effects in +*MAT_083, *MAT_181, and *MAT_183. +• Add automatic generation of null shells for quadratic shell contact (*PART_DU- +PLICATE_NULL_OVERLAY). +• Add beam contact forces to rcforc output (*DATABASE_RCFORC). +• Add SHL4_TO_SHL8 option to *ELEMENT_SHELL to automatically convert 4- +node shells to 8-node quadratic shells. +• Add 3-node beam element with quadratic interpolation that is tailored for the +piping industry. It includes 12 degrees of freedom, including 6 ovalization +degrees of freedom, per node for a total of 36 DOF. An internal pressure can be +given that can stiffen and elongate the pipe. +◦ ELFORM = 14 in *SECTION_BEAM. +◦ *ELEMENT_BEAM_ELBOW. +◦ NEIPB in *DATABASE_EXTENT_BINARY to direct output of elbow loop- +stresses to d3plot. Otherwise, output goes to ASCII file elbwls.k. +◦ Supported by a subset of material models including mats 3, 4, 6, 153, 195. +• Add discrete element option DE to *DATABASE_TRACER. +◦ Includes variable RADIUS. average result of all + RADIUS > 0: Reports the average result of all DE particles in a spher- +ical volume having radius = RADIUS and centered at the tracer. + RADIUS < 0: Reports result of the closest particle to the tracer. +INTRODUCTION +◦ If a tracer node NID is given, then the tracer moves with this node. The +node must belong to a DES. +• Add new options *PART_COMPOSITE_LONG and *ELEMENT_SHELL_COM- +POSITE_LONG. In contrast to “COMPOSITE”, one integration point is defined +per card. This is done to allow for more informations, e.g. new variable “ply +id”. +• Add support of *MAT_ADD_EROSION option NUMFIP < 0 for standard (non- +GISSMO) failure criteria. Only for shells. +• Add viscoplastic behavior to *MAT_157, i.e., parameter LCSS can now refer to a +table with strain rate dependent yield curves. +• Add singular finite element with midside nodes for 2D plane strain fracture +analysis (ELFORM = 55 in *SECTION_SHELL). This is an 8-noded element and +can induce a singular displacement field by moving mid-side nodes to quarter +locations. +• If HCONV < 0 in *AIRBAG_PARTICLE, |HCONV| is a curve of heat convection +coefficient vs. time. +• Add new option DECOMPOSITION for *AIRBAG_PARTICLE -- MPP only.This +will automatically invoke the recommended decomposition commands, *CON- +TROL_MPP_DECOMPOSITION_BAGREF (if applicable) and *CONTROL_- +MPP_DECOMPOSITION_ARRANGE_PARTS, for the bag. +• Add new blockage option for vents in *AIRBAG_PARTICLE: +◦ blockage considered + .eq.0: no + .eq.1: yes + .eq.2: yes, exclude external vents + .eq.3: yes, exclude internal vents + .eq.4: yes, exclude all vents +• Add option in *CONTROL_CPM to consider CPM in the time step size calcula- +tion. +• When using *AIRBAG_PARTICLE with IAIR = 2, user should keep mole / +particle similar between inflator gas and initial air particles to ensure the correct +elastic collision. If different by more than 10%, code will issue warning message +and provide the suggested initial air particle number. +• Enable *DEFINE_CURVE_FUNCTION for *SECTION_POINT_SOURCE_MIX- +TURE and *SECTION_POINT_SOURCE. +• Make *BOUNDARY_PRESCRIBED_MOTION_SET compatible with *CON- +TROL_REFINE +INTRODUCTION +• Change *BOUNDARY_ACOUSTIC_COUPLING_MISMATCH to rank order +opposing acoustic faces and structural segments by proximity, thereby accelerat- +ing the preprocessing stage, enhancing reliability and allowing some liberaliza- +tion of the search parameters. +• Implement hemispherical geometry for particle blast (*DEFINE_PBLAST_- +GEOMETRY). +• Add explosive type for *PARTICLE_BLAST. +• For particle-based blast *PARTICLE_BLAST: +◦ Include random distribution of initial air molecules +◦ Modify algorithm to account for the non-thermally-equilibrated state of +high velocity gas. +• Improve particle contact method for particle-based blast loading *PARTICLE_- +BLAST. +• *CONTACT now works for parts refined using *CONTROL_REFINE_SOLID or +*CONTROL_REFINE_SHELL. +• Improve calculation of shell element contact segment thicknesses, particularly at +material boundaries. +• MPP: Add output to rcforc file for *CONTACT_AUTOMATIC_TIEBREAK to +record the # of nodes tied, and the total tied area. +• MPP: Add calculation of “contact gap” for master side of FORMING contact. +• MPP: Add support for table-based friction (FS = 2.0) to groupable contact. +• Implement splitting-pinball contact, Belytschko & Yeh (1992, 1993). This new +contact option is invoked by setting SOFT = 2, SBOPT = 3 and DEPTH = 45. A +penetration check method based on LS-PrePost version 4.0 is implemented for +the new bilinear-patch-based contact, SOFT = 2, DEPTH = 45 & Q2TRI = 0. The +new method provides more accurate intersection information when Q2TRI = 0. +• Add support for birth time for *CONTACT_2D_AUTOMATIC_TIED. +• Improve the segment based single surface contact search for thick segment pairs +that are too close together. The code was not working well with triangluar +segments. This change affects models with shell segments that have thickness +greater than about 2/3 of the segment length. +• Enable segment based quad splitting options to work when shell sets or segment +sets are used to define the surface that will be split. This is really a bug fix +because there was no check to prevent this and the result was writing past the +allocated memory for segment connectivites. +• Allow *CONSTRAINED_INTERPOLATION to use node set to define the +independent nodes. +INTRODUCTION +• Add a length unit to the tolerance used for the checking of noncoincident nodes +in *CONSTRAINED_JOINTs excluding spherical joints. The old tolerance was +1.e-3. The new tolerance is 1.e-4 times the distance between nodes 1 and 3. The +error messages were changed to warnings since this change might otherwise +cause existing models to stop running. +• Add d3hsp output +for *CONSTRAINED_INTERPOLATION_SPOTWELD +(SPR3) and *CONSTRAINED_SPR2. Can be deactivated by setting NPOPT = 1 +on *CONTROL_OUTPUT. +• Support NFAIL1 and NFAIL4 of *CONTROL_SHELL in coupled thermal- +mechanical analysis, i.e. erode distorted elements instead of error termination. +• PTSCL on *CONTROL_CONTACT can be used to scale contact force exerted on +shell formulations 25, 26, 27 as well as shell formulations 2, 16 (IDOF = 3). +• Use SEGANG in *CONTROL_REMESHING to define positive critical angle (unit +is radian) to preserve feature lines in 3D tetrahedral remeshing (ADPOPT = 2 in +*PART). +• For 3D solid adaptive remeshing including ADPOPT = 2 and ADPOPT = 3 +(*PART), the old mesh will be used automatically if the remesher fails generating +a new mesh. +• Add option INTPERR on *CONTROL_SHELL (Optional Card 3, Column 8). By +default, warning messages INI+143/144/145 are written in case of non-matching +number of integration points between *INITIAL_STRESS_SHELL and *SEC- +TION_SHELL. Now with INTPERR = 1, LS-DYNA can terminate with an error. +• Add variable D3TRACE on *CONTROL_ADAPTIVE: The user can now force a +plot state to d3plot just before and just after an adaptive step. This option is +necessary for tracing particles across adaptive steps using LS-PrePost. +• By putting MINFO = 1 on *CONTROL_OUTPUT, penetration info is written to +message files for mortar contact., see also *CONTACT_…. Good for debugging +implicit models, not available for explicit. +• Change the default scale factor for binary file sizes back to 70. This value can be +changed using “x=” on the execution line. In version R7.0, the default value of x +is 4096, and that sometimes leads to difficulty in postprocessing owing to the +large size of the d3plot file(s). +• Enable *CONTROL_OUTPUT flag, EOCS, which wasn't having any effect on the +shells output to elout file. +• *DATABASE_FSI_SENSOR: Create sensors at solid faces in 3D and at shell sides +in 2D. +• *DATABASE_PROFILE: Implement the option DIR = 4 to plot data with +curvilinear distributions and the flag UPDLOC to update the profile positions. +• In *CONTROL_SHELL, add options for deletion of shells based on: +INTRODUCTION +◦ diagonal stretch ratio (STRETCH) +◦ w-mode amplitude in degrees (W-MODE) +• New element formulation ELFORM = 45 in *SECTION_SOLID: Tied Meshfree- +enriched FEM (MEFEM). This element is based on the 4-noded MEFEM element +(ELFORM = 43, *SECTION_SOLID). Combined with *CONSTRAINED_TIED_- +NODES_FAILURE, *SET_NODE_LIST and cohesive model, this element can be +used to model dynamic multiple-crack propagation along the element bounda- +ries. +• New high order tetrahedron CPE3D10 based on Cosserat Point theory can be +invoked by specifying element formulation ELFORM = 16 and combining this +with hourglass formulation IHQ = 10. See *SECTION_SOLID and *HOUR- +GLASS. +• Add database D3ACS for collocation acoustic BEM (*FREQUENCY_DOMAIN_- +ACOUSTIC_BEM) to show the surface pressure and normal velocities. +• Implement biased spacing for output frequencies for random vibration (*FRE- +QUENCY_DOMAIN_RANDOM_VIBRATION). +• Add frequency domain nodal or element velocity output for acoustic BEM +(*FREQUENCY_DOMAIN_ACOUSTIC_BEM). +• Implement boundary acoustic mapping to acoustic BEM in MPP (*BOUND- +ARY_ACOUSTIC_MAPPING). This is enabled only for segment sets at present. +• Implement panel contribution analysis capability to Rayleigh method (*FRE- +QUENCY_DOMAIN_ACOUSTIC_BEM_PANEL_CONTRIBUTION). +• Implement a scheme to map velocity boundary condition from dense BEM mesh +to coarse mesh to speed up the computation (*FREQUENCY_DOMAIN_- +ACOUSTIC_BEM). +• Add user node ID for acoustic field points in D3ATV (*FREQUENCY_DO- +MAIN_ACOUSTIC_BEM). Now D3ATV is given for multiple field points, and +multiple frequencies. +• Add database D3ATV for acoustic transfer vector binary plot (*FREQUENCY_- +*DATABASE_FREQUENCY_BINARY_- +DOMAIN_ACOUSTIC_BEM_ATV, +D3ATV). +• Implement acoustic panel contribution analysis to collocation BEM and dual +collocation BEM (*FREQUENCY_DOMAIN_ACOUSTIC_BEM). +• Enable *FREQUENCY_DOMAIN_MODE in response spectrum analysis (*FRE- +QUENCY_DOMAIN_RESPONSE_SPECTRUM). +• Implement an option to read in user-specified nodal velocity history data for +running BEM acoustics (*FREQUENCY_DOMAIN_ACOUSTIC_BEM). +INTRODUCTION +• Extend Kirchhoff acoustic method +to MPP +(*FREQUENCY_DOMAIN_- +ACOUSTIC_BEM). +• Extend response spectrum analysis to multiple load spectra cases (*FREQUEN- +CY_DOMAIN_RESPONSE_SPECTRUM). +• Add BAGVENTPOP for *SENSOR_CONTROL. This allows user more flexibilty +controlling the pop-up of the venting hole of *AIRBAG_HYBRID and +*AIRBAG_WANG_NEFSKE +• Add command *SENSOR_DEFINE_FUNCTION. Up to 15 *DEFINE_SENSORs +can be referenced in defining a mathematical operation. +• LAYER of *SENSOR_DEFINE_ELEMENT can now be an integer “I” represent- +ing the Ith integration point at which the stress/strain of the shell or tshell ele- +ment will be monitored. +• Add control of *LOAD_MOVING_PRESSURE by using *SENSOR_CONTROL. +• Add thick shells to the ETYPE option list of *SENSOR_DEFINE_ELEMENT. +• Add *CONTROL_MPP_MATERIAL_MODEL_DRIVER in order to enable the +Material Model Driver for MPP (1 core). +• Add table input of thermal expansion coefficient for *MAT_270. Supports +temperature-dependent curves arranged according to maximum temperature. +• Add table input of heat capacity for *MAT_T07. Supports temperature depend- +ent curves arranged according to maximum temperature. +• Add two more kinematic hardening terms for *MAT_DAMAGE_3/MAT_153, c2 +& gamma2. +• Add materials *MAT_CONCRETE_DAMAGE_REL3/*MAT_072R3 and *MAT_- +CSCM_CONCRETE/*MAT_159 to Interactive Material Model Driver. +• Enable *MAT_JOHNSON_COOK/*MAT_015 for shell elements to work with +coupled structural / thermal analysis. +• Allow *MAT_SOIL_AND_FOAM/*MAT_005 to use positive or negative abscissa +values forload curve input of volumetric strains. +• Add *MAT_ACOUSTIC elform = 8 support for pyramid element case using 5-pt +integration. +• Add support to *MAT_219 (*MAT_CODAM2) for negative AOPT values which +point to coordinate system ID's. +• Modify *MAT_224 so it uses the temperatures from the thermal solution for a +coupled thermal-mechanical problem. +• Add alternative solution method (Brent) for *MAT_015 and *MAT_157 in case +standard iteration fails to converge. +INTRODUCTION +• Add shell element IDs as additional output to messag file for *MAT_036's +warning “plasticity algorithm did not converge”. +• For *MAT_USER_DEFINED_MATERIAL_MODELS, the subroutines crvval and +tabval can be called with negative curve / table id which will extract values from +the user input version of the curve or table instead of the internally converted +“100-point” curve / table. +• In the damage initiation and evolution criteria of *MAT_ADD_EROSION +(invoked by IDAM < 0), add the option Q1 < 0 for DETYP = 0. Here, |Q1| is the +table ID defining the ufp (plastic displacement at failure) as a function of triaxial- +ity and damage value, i.e., ufp = ufp(eta, D), as opposed to being constant which +is the default. +• In *MAT_RHT, ONEMPA = -6 generates parameters in g, cm, and 𝜇S and +ONEMPA = -7 generates parameters in g, mm, and mS +• In *MAT_SIMPLIFIED_RUBBER/FOAM, STOL > 0 invokes a stability analysis +and warning messages are issued if an unstable stretch point is found within a +logarithmic strain level of 100%. +• Implement *DATABASE_ALE to write time history data (volume fractions, +stresses, …) for a set of ALE elements. Not to be confused with *DATABASE_- +ALE_MAT. +• Implement *DELETE_PART in small restarts for ALE2D parts. +• Add conversion of frictional contact energy into heat when doing a coupled +thermal-mechanical problem for SPH (variable FRCENG in *CONTROL_CON- +TACT). This option applys to all 3D contact types supported by SPH particles. +• For keyword *DEFINE_ADAPTIVE_SOLID_TO_SPH, add support of explicit +SPH thermal solver for the newly generated SPH particles which were converted +from solid elements. The temperatures of those newly generated SPH particles +are mapped from corresponding solid elements. +• Implement DE to surface tied contact *DEFINE_DE_TO_SURFACE_TIED. The +implementation includes bending and torsion. +• Implement keyword *DEFINE_DE_HBOND to define heterogeneous bond for +discrete element spheres (DES). DES (*ELEMENT_DISCRETE_SPHERE) with +different material models can be bonded. +• Implement keyword *INTERFACE_DE_BOND to define multiple failure models +for various bonds within one part or between different parts through the key- +word *DEFINE_DE_HBOND. +• Implement *DEFINE_DE_TO_BEAM_COUPLING for coupling of discrete +element spheres to beam elements. +INTRODUCTION +• Add variable MAXGAP in *DEFINE_DE_BOND to give user control of distance +used in judging whether to bond two DES together or not, based on their initial +separation. +• Add IAT = -3 in *CONTROL_REMESHING_EFG, which uses FEM remapping +scheme in EFG adaptivity. Compared to IAT = -2, -1, 1, 2, IAT = -3 is faster and +more robust but less accurate. +• Add control flag MM in *CONTROL_REMESHING_EFG to turn on/off +monotonic mesh resizing for EFG 3D general remeshing (ADPOPT = 2 in +*PART). +• *CONTROL_IMPLICIT_BUCKLING - Extend Implicit Buckling Feature to allow +for Implicit problems using Inertia Relief. This involves adding the Power +Method as a solution technology for buckling eigenvalue problems. Using the +power method as an option for buckling problems that are not using inertia relief +has been added as well. +• Extend Implicit Buckling to allow for Intermittent extraction by using negative +values of NMODE on *CONTROL_IMPLICIT_BUCKLING similar to using +negative values of NEIG on *CONTROL_IMPLICIT_EIGENVALUE. +• Extend implicit-explicit switching specified on *CONTROL_DYNAMIC_RELAX- +ATION to allow explicit simulation for the dynamic relaxation phase and implic- +it for the transient phase. +• New implementation for extracting resultant forces due to joints for implicit +mechanics. +• New implementation of extracting resultant forces due to prescribed motion for +implicit mechanics. +• Add support for IGAP > 2 in implicit, segment based (SOFT = 2) contact. +• Add constraint-based, thermal nodal coupling for *CONSTRAINED_LA- +GRANGE_IN_SOLID. HMIN < 0 turns it on. +• Add FRCENG = 2 on CONTROL_CONTACT keyword. +◦ if FRCENG = 1, convert contact frictional energy to heat. +◦ if FRCENG = 2, do not convert contact frictional energy to heat. +• Add effect of thermal time scaling (TSF in *CONTROL_THERMAL_SOLVER) to +2D contact. +• Add new pfile decomposition region option: partsets. Takes a list of part sets +(*SET_PART) from the keyword input and uses them to define a region, e.g., +region { partsets 102 215 sy 1000 } This example would take partsets, scale y by +1000, and decompose them and distribute them to all processors. +• Reduce MPP memory usage on clusters. +• Add MPP support for *ELEMENT_SOURCE_SINK. +INTRODUCTION +• Add new pfile options: +◦ decomp { d2r_as_rigid } +◦ decomp { d2ra_as_rigid } +which cause materials appearing in “*DEFORMABLE_TO_RIGID” and “*DE- +FORMABLE_TO_RIGID_AUTOMATIC” to have their computational costs set as +if they were rigid materials during the decomposition. +• Add option ISRCOUT to *INCLUDE_STAMPED_PART to dump out the +transformed source/stamp mesh. +• *CONTROL_FORMING_OUTPUT: Allow NTIMES to be zero; support birth and +death time; support scale factor in curve definition. +• Add a new option (INTFOR) to *CONTROL_FORMING_OUTPUT to control the +output frequency of the INTFOR database. +• Add new features (instant and progressive lancing) in *ELEMENT_LANCING +for sheet metal lancing simulation. +• Add a new keyword: *CONTROL_FORMING_INITIAL_THICKNESS. +• Add a new option for springback compensation: *INCLUDE_COMPENSA- +TION_ORIGINAL_TOOLS. +• Add +a new +keyword: +*INTERFACE_COMPENSATION_NEW_PART_- +CHANGE. +• Add a new keyword (*DEFINE_CURVE_BOX_ADAPTIVITY) to provide better +control of mesh refinement along two sides of the curve. +• Isogeometric analysis: contact is available in MPP. +• Normalize tangent vectors for local coordinate system for the rotation free +isogeometric shells. +• Add support for dumping shell internal energy density for isogeometric shells +(*ELEMENT_SHELL_NURBS_PATCH) via interpolation shells. +• Add support for dumping of strain tensor (STRFLG.eq.1) for isogeometric shells +(*ELEMENT_SHELL_NURBS_PATCH) via interpolation shells. +• Add H-field, magnetization and relative permeability to d3plot output. +• *ICFD_INITIAL: Add a reference pressure (pressurization pressure) for when no +pressure is imposed on the boundaries. +• Add the initialization of all nodes at once by setting PID = 0. +• Add the non-inertial reference frame implementation defined by the keyword +*ICFD_DEFINE_NONINERTIAL. +• Add several new state variables to LSO. Please refer to the LSO manual to see +how to print out the list of supported variables. +INTRODUCTION +• Add support for FSI with thick shells. +• 2D shells are now supported for FSI in MPP. In the past only beams could be +used in MPP and beams and shells could be used in SMP. +• The keyword ICFD_CONTROL_FSI has a new field to control the sensitivity of +the algorithm to find the solid boundaries used in FSI calculations. +• The 2D mesh now generates semi-structured meshes near the boundaries. +• Add heat flux boundary condition using ICFD_BOUNDARY_FLUX_TEMP. +• Add divergence-free and Space Correlated Synthetic Turbulence Inlet Boundary +Condition for LES (Smirnov et al.) using *ICFD_BOUNDARY_PRESCRIBED_- +VEL. +• *ICFD_BOUNDARY_PRESCRIBED_VEL: Add inflow velocities using the wall +normal and a velocity magnitude using the 3rd field VAD. +• Add the activation of synthetic turbulence using the 3rd field VAD. +• Add the option to control the re-meshing frequency in both keywords: see +*ICFD_CONTROL_ADAPT_SIZE and *ICFD_CONTROL_ADAPT. +• *ICFD_CONTROL_TURB_SYNTHESIS: control parameters for the synthetic +turbulence inflow. +• *ICFD_BOUNDARY_PRESCRIBED_MOVEMESH: Allows the mesh to slide on +the boundaries following the cartesian axis. +• Add a PART_SET option for *CESE_BOUNDARY_…_PART cards. +• Bring in more 2D mesh support, both from the PFEM mesher and a user input +2D mesh (via *ELEMENT_SOLID with 0 for the last 4 of 8 nodes). +• Enable the 2D ball-vertex mesh motion solver for the 2D CESE solver. +• Add new input cards: +◦ *CESE_BOUNDARY_CYCLIC_SET +◦ *CESE_BOUNDARY_CYCLIC_PART +• Add code for 2D CESE sliding boundary conditions. +• Add support in CESE FSI for 2D shells in MPP. +• Add support for CESE FSI with thick shells. +• Add 2D & 2D-axisymmetric cases in the CESE-FSI solver (including both +immersed boundary method & moving mesh method) . +• Add the CSP reduced chemistry model with 0D, 2D, and 3D combustion. The +2D and 3D combustion cases couple with the CESE compressible flow solver. +• Add the G-scheme reduced chemistry model only for 0D combustion. +• Add two different reduced chemistry models. +INTRODUCTION +◦ The Computational Singular Perturbation (CSP) reduced model is imple- +mented with existing compressible CESE solver. The CSP is now working +on 0-dimensional onstant volume and pressure combustion, 2-D, and 3-D +combustion problems. +◦ The new reduced chemistry model, G-scheme, is implemented, but cur- +rently works only 0-dimensional problems such as constant combustors. +• Jobid can now be changed in a restart by including “jobid=“ on the restart +execution line. Previously, the jobid stored in d3dump could not be overwritten. +• Part labels (PID) can be up to 8 characters in standard format; 20 characters in +long format. +• Labels for sections (SID), materials (MID), equations of state (EOSID), hourglass +IDs (HGID), and thermal materials (TMID) can be up to 10 characters in standard +format; 20 characters in long format. +• Create bg_switch and kill_by_pid for SMP. Both files will be removed at the +termination of the run. +• Increase the overall length of command line to 1000 characters and length of each +command line option to 50 characters. +• Increase MPP search distance for tied contacts to include slave and master +thicknesses. +• For *CONTACT_AUTOMATIC_…_MORTAR, the mortar contact now supports +contact with the lateral surface of beam elements. +• On *CONTACT_..._MORTAR, IGAP.GT.1 stiffens the mortar contact for large +penetrations. The mortar contact has a maximum penetration depth DMAX that +depends on geometry and input parameters; if penetration is larger than this +value the contact is released. To prevent this release, which is unwanted, the +user may put IGAP.GT.1 which stiffens the behavior for penetrations larger than +0.5*DMAX without changing the behavior for small penetrations. This should +hopefully not be as detrimental to convergence as increasing the overall contact +stiffness. +• For initialization by prescribed geometry in dynamic relaxation (IDRFLG = 2, +*CONTROL_DYNAMIC_RELAXATION), add an option where displacements +are not imposed linearly but rather according to a polar coordinate system. This +option was added to accommodate large rotations. +• The flag RBSMS on *CONTROL_RIGID is now active for regular and selective +mass scaling to consistently treat interfaces between rigid and deformable bodies +• Remove static linking for l2a as many systems do not have the required static +libraries. +• Add IELOUT in *CONTROL_REFINE to handle how child element data is +handled in elout (*DATABASE_HISTORY_SOLID and *DATABASE_HISTO- +INTRODUCTION +RY_SHELL). Child element data are stored if IELOUT = 1 or if refinement is set +to occur only during initialization. +• Include eroded hourglass energy in hourglass energy in glstat file to be con- +sistent with KE & IE calculations so that the total energy = kinetic energy + +internal energy + hourglass energy + rigidwall energy. +• Remove *DATABASE_BINARY_XTFILE since it is obsolete. +• When using *PART_AVERAGED for truss elements (beam formulation 3), +calculate the time step based on the total length of the combined macro-element +instead of the individual lengths of each element. +• Enable writing of midside nodes to d3plot or 6- and 8-node quadratic shell +elements. +• Write complete history variables to dynain file for 2D solids using *MAT_NULL +and equation-of-state. +• Shell formulations 25, 26, and 27 are now fully supported in writing to dynain +file (*INTERFACE_SPRINGBACK_LSDYNA). +• Shell formulations 23 (quad) and 24 (triangle) can now be mixed in a single part. +When ESORT = 1 in *CONTROL_SHELL, triangular shells assigned by *SEC- +TION_SHELL to be type 23 will automatically be changed to type 24. +• Enable hyperelastic materials (those that use Green's strain) to be used with thick +shell form 5. Previously, use of these materials (2, 7, 21, 23, 27, 30, 31, 38, 40, 112, +128, 168, and 189) with thick shell 5 has been an input error. +• Update acoustic BEM to allow using *DEFINE_CURVE to define the output +frequencies (*FREQUENCY_DOMAIN_ACOUSTIC_BEM). +• When using *CONTROL_SPOTWELD_BEAM, convert *DATABASE_HISTO- +RY_BEAM to *DATABASE_CROSS_SECTION and *INITIAL_AXIAL_FORCE_- +BEAM to *INITIAL_STRESS_CROSS_SECTION for the spotweld beams that are +converted to hex spotwelds. +• Improve output of *INITIAL_STRESS_BEAM data to dynain via *INTERFACE_- +SPRINGBACK_LSDYNA. Now, large format can be chosen, history variables +are written, and local axes vectors are included. +• Update *MAT_214 (*MAT_DRY_FABRIC) to allow fibers to rotate independent- +ly. +• Enable regularization curve LCREGD of *MAT_ADD_EROSION to be used with +FLD criterion, i.e. load curve LCFLD. Ordinate values (major strain) will be +scaled with the regularization factor. +• Modify *MAT_ADD_EROSION parameter EPSTHIN: +◦ EPSTHIN > 0: individual thinning for each IP from z-strain (as before). +◦ EPSTHIN < 0: averaged thinning strain from element thickness (new). +INTRODUCTION +• Enable regularization curve LCREGD of *MAT_ADD_EROSION to be used with +standard (non-GISSMO) failure criteria. Users can now define a failure criterion +plus IDAM = 0 plus LCREGD = scaling factor vs. element size to get a regular- +ized failure criterion. +• *MAT_ADD_EROSION: equivalent von Mises stress SIGVM can now be a +function of strain rate by specifying a negative load curve ID. +• *SECTION_ALE1D and *SECTION_ALE2D now work on multiple processors +(SMP and MPP). +• *CONSTRAINED_LAGRANGE_IN_SOLD ctype 4/5 now converts friction +energy to heat. Note it only works for ALE elform 12. +Capabilities added September 2013 – January 2015 to create LS-DYNA R8.0: +See release notes (published separately) for further details. +• Add RDT option for *AIRBAG_SHELL_REFERENCE_GEOMETRY. +• LCIDM and LCIDT of *AIRBAG_HYDRID can now be defined through *DE- +FINE_CURVE_FUNCTION. +• New variable RGBRTH in *MAT_FABRIC to input part-dependent activation +time for airbag reference geometry. +• Negative PID of *AIRBAG_INTERACTION considers the blockage of partition +area due to contact. +• Enhancements to *AIRBAG_PARTICLE: +◦ New blockage (IBLOCK) option for vents. +◦ External work done by inflator gas to the structure is reported to glstat. +◦ Enhance segment orientation checking of CPM bag and chambers. +◦ Allow user to excluded some parts surface for initial air particles. +◦ Support compressing seal vent which acts like flap vent. +◦ Support Anagonye and Wang porosity equation through *MAT_FABRIC. +◦ Add keyword option _MOLEFRACTION. +• Add_ID keyword option +*AIRBAG_REFERENCE_GEOMETRY and +*AIRBAG_SHELL_REFERENCE which includes optional input of variables for +scaling the reference geometry. +to +• Enable *DEFINE_CURVE_FUNCTION for *AIRBAG_SIMPLE_AIRBAG_MOD- +EL. +• Calculate heat convection (HCONV) between environment and airbag in +consistent fashion when TSW is used to switch from a particle airbag to a control +volume. +INTRODUCTION +• For *AIRBAG_PARTICLE, add ENH_V = 2 option for vent hole such that two- +way flow can occur, i.e., flow with or against the pressure gradient. +• *BOUNDARY_ALE_MAPPING: add the following mappings: 1D to 2D, 2D to +2D, 3D to 3D. +• *SET_POROUS_ALE: new keyword to define the properties of an ALE porous +media by an element set. The porous forces are computed by *LOAD_BODY_- +POROUS. +• *ALE_FSI_SWITCH_MMG: applies also now to 2D. +• *ALE_SWITCH_MMG: new keyword to switch multi-material groups based on +criteria defined by the user with *DEFINE_FUNCTION. +• *CONTROL_ALE: Allow PREF (reference pressure) to be defined by materials. +• Implement *ALE_COUPLING_NODAL_DRAG to model the drag force coupling +between discrete element spheres or SPH particles and ALE fluids. +• Implement *ALE_COUPLING_RIGID_BODY as an efficient alternative for +constraint type coupling between ALE fluids and a Lagrangian rigid body. +• Error terminate if *BOUNDARY_SPC_NODE_BIRTH_DEATH is applied to a +node that belongs to a rigid body. +• Modify *BOUNDARY_PRESCRIBED_ORIENTATION_VECTOR to accommo- +date bodies which undergo no changes in orientation. +• Add a new keyword *BOUNDARY_SPC_SYMMETRY_PLANE. +• Solid part or solid part set is now allowed for *PARTICLE_BLAST. +• Add ambient pressure boundary condition flag BC_P for *PARTICLE_BLAST. +• New command *DEFINE_PBLAST_GEOMETRY allows the high explosive +domain for*PARTICLE_BLAST to be defined by various geometric shapes. +• Allow multiple *PARTICLE_BLAST definitions. +• Add *DATABASE_PBSTAT to output particle blast statistics. +• Output the initial volume and initial mass of HE particles and air particles for +*PARTICLE_BLAST to d3hsp. +• Add the command *CESE_BOUNDARY_BLAST_LOAD to allow a blast +described by the *LOAD_BLAST_ENHANCED command to be used as a +boundary condition in CESE. +• Modify the FSI interface reflective boundary condition pressure treatment in +some calculations for the moving mesh and immersed boundary solvers. +• Change the CESE derivatives calculation method to use the current values of +flow variables. +INTRODUCTION +• Add two new MAT commands for CESE solver, *CESE_MAT_000 and *CESE_- +MAT_002. +• Add a non-inertial reference frame solver for fluid and FSI problems using the +moving-mesh method. +• For the moving mesh CESE solver, replace the all-to-all communication for +conjugate heat and FSI quantities with a sparse communication mechanism. +• Add structural element erosion capability to the immersed boundary method +CESE FSI solver (serial capability only). +• Add 2D cyclic boundary conditions capability. +• Add a NaN detection capability for the CESE solver. +• Switch all CESE boundary conditions that use a mesh surface part to define the +boundary to use the character string "MSURF" instead of "PART" in the option +portion of the keyword name. +• Add missing temperature interpolation in time for imposing solid temperatures +as a boundary condition in the CESE solver. +• Optimize the IDW-based mesh motion for the CESE moving mesh solver. +• Treat the input mesh as 3D by default for the CESE solver. +• All of the chemistry features mentioned below are coupled only to the CESE +compressible flow solver when 2D or 3D calculations are involved. +• Chemical source Jacobians have been added. +• Introduce *CHEMISTRY_CONTROL_PYROTECHNIC and *CHEMISTRY_PRO- +PELLANT_PROPERTIES for airbag applications. In conjuction with these com- +mands, basic airbag inflator models are implemented. +• The pyrotechnic inflator model using NaN3/Fe2O3 propellant is newly +implemented. To connect with the existing ALE airbag solver, two load curves, +mass flow rate and temperature, are saved in "inflator_outfile" as a function of +time. This model computes three sub-regions: combustion chamber, gas plenum, +and discharge tank. Each region can be initialized with different *CHEMISTRY_- +COMPOSITION models, which means that user can compute Propellant+Gas +hybrid mode. +• The following 0-dimensional combustion problems have been improved: +constant volume, constant pressure, and CSP. +• For iso-combustion. temperature and species mass fractions as a function of time +are displayed on screen and saved in "isocom.csv" to plot with LS-PrePost. +• Another chemical ODE integration method has been implemented. +• The output file of the pyrotechnic inflator is updated so that this file can be read +from ALE solver for an airbag simulation. +INTRODUCTION +• 2-D and 3-D TNT gaseous blast explosives, categorized as TBX (thermobaric +explosives), are implemented for the Euler equation systems (CESE-only). Also, +3-D TNT blast + aluminum combustion for serial problems is now implemented. +• Implement a mix modeling method for use with CESE solvers. +• Modify *CHEMISTRY-related keyword commands to allow multiple chemistry +models in the same problem. +• Add command *CHEMISTRY_MODEL which identifies the files that define a +Chemkin chemistry model. +• Modify the following commands such that the files related to the chemistry +model have been removed. These commands are only used to select the type of +chemistry solver: +◦ *CHEMISTRY_CONTROL_CSP +◦ *CHEMISTRY_CONTROL_FULL +◦ *CHEMISTRY_CONTROL_1D +• Modify *CHEMISTRY_DET_INITIATION where the files related to the chemis- +try model have been removed, and the Model ID used is inferred through a +reference to a chemistry composition ID. +• Modify *CHEMISTRY_COMPOSITION and *CESE_CHEMISTRY_D3PLOT to +add model ID. +• Add *CONTACT_TIED_SHELL_EDGE_TO_SOLID for transferring moments +from shells into solids. +• Add frictional energy calculation for beams in *CONTACT_AUTOMATIC_GEN- +ERAL. +• Enhance ERODING contacts for MPP. The new algorithm uses a completely +different approach to determining the contact surface. The old algorithm started +from scratch when identifying the exterior of the parts in contact. The new +algorithm is smarter about knowing what has been exposed based on what is +eroded, and is faster. +• Force EROSOP = 1 for all ERODING type contacts, with a warning to the user if +they had input it as 0. +• Add error check in case of a contact definition with an empty node set being +given for the slave side. +• Modify output of ncforc (*DATABASE_NCFORC) in order to support output in +a local coordinate system. +• For ERODING contacts, reduce memory allocated for segments so each interior +segment is only allocated once. +• Add keyword *DEFINE_CONTACT_EXCLUSION (MPP only) to allow for +nodes tied in some contacts to be ignored in certain other contacts. +INTRODUCTION +• Rewrite meshing of *CONTACT_ENTITY to use dynamic memory, which +removes the previous limit of 100 meshed contact entities. There is now no limit. +• Remove undocumented release condition for MPP’s *CONTACT_AUTOMAT- +IC_TIEBREAK, options 5 and greater. +• Add new experimental "square edge" option to select SOFT = 0,1 contacts. This +new option applies only to AUTOMATIC_SINGLE_SURFACE and the segment- +to-segment treatment of AUTOMATIC_GENERAL, and is invoked by setting +SRNDE = 2 on *CONTACT's Optional Card E. This new option does not apply to +SOFT = 2; SOFT = 2 square edge option is set using SHLEDG in *CONTROL_- +CONTACT. +• BT and DT in *CONTACT can be set to define more than one pair of +birthtime/death-time for the contact by pointing to a curve or table. These pairs +can be unique for the dynamic relaxation phase and the normal phase of the +simulation. +• Add EDGEONLY option to *CONTACT_AUTOMATIC_GENERAL to exclude +node-to-segment contact and consider only edge-to-edge and beam-to-beam +contact. +• VDC defines the coefficient of restituion when variable CORTYP is defined. +*CON- +Available +TACT_AUTOMATIC_SURFACE_TO_SURFACE, and *CONTACT_AUTOMAT- +IC_SINGLE_SURFACE; SOFT = 0 or 1 only. +*CONTACT_AUTOMATIC_NODES_TO_SURFACE, +for +• Enhancements for *CONTACT_AUTOMATIC_GENERAL: +◦ Add beam to beam contact option CPARM8 in *PART_CONTACT (MPP +only). +◦ Add option whereby beam generated on exterior shell edge will be shifted +into the shell by half the shell thickness. In this way, the shell-edge-to- +shell-edge contact starts right at the shell edge and not at an extension of +the shell edge . +• Implement *CONTROL_CONTACT PENOPT = 3 option to *CONTACT_AUTO- +*CONTACT_ERODING_NODES_TO_- +MATIC_NODES_TO_SURFACE and +SURFACE for SMP. +• Update segment based (SOFT = 2) contact to improve accuracy at points away +from the origin. The final calculations are now done with nodal and segment +locations that have been shifted towards the origin so that coordinate values are +small. +• Enable user defined friction (*USER_INTERFACE_FRICTION; subroutine usrfrc) +for MPP contact SOFT = 4. +INTRODUCTION +• Unify automatic tiebreak messages for damage start and final failure. SMP and +MPP should now give the same output to d3hsp and messag. This affects +*CONTACT_AUTOMATIC_...TIEBREAK, OPTIONs 6, 7, 8, 9, 10, and 11. +• *CONTACT_ADD_WEAR: Associates wear calculations to a forming contact +interface whose quantities can be posted in the intfor database file. Adaptivity is +supported. +• *CONTACT_..._MORTAR: +◦ Detailed warning outputs activated for mortar contact, also clarifies echoed +data in d3hsp. +◦ Contact thickness made consistent with other contacts in terms of priority +between ISTUPD on CONTROL_SHELL, SST on CONTACT and OPTT on +PART_CONTACT. +◦ Efficency improvement of bucket sort in mortar contact allowing for signif- +icant speedup in large scale contact simulations. +• *CONTACT_..._MORTAR, *DEFINE_FRICTION, *PART_CONTACT: +◦ Mortar contact supports FS = -1.0, meaning that frictional coefficients are +taken from *PART_CONTACT parameters. +◦ Mortar contact supports FS.EQ.-2 meaning that friction is taken from *DE- +FINE_FRICTION. +• *CONTACT_AUTOMATIC_SINGLE_SURFACE_MORTAR: +IG- +NORE.LT.0 for single surface mortar contact will ignore penetrations of seg- +ments that belong to the same part. +Using +• Friction factors are now a function of temperature for *CONTACT_..._THER- +MAL_FRICTION. +• *SET_POROUS_LAGRANGIAN: new keyword to define the porosity of +Lagrangian elements in an element set. The porous forces are computed by +*CONSTRAINED_LAGRANGE_IN_SOLID ctype = 11 or 12. +• *CONSTRAINED_LAGRANGE_IN_SOLID: CTYPE = 12 is now also available in +2D. +• Add helix angle option for *CONSTRAINED_JOINT_GEARS. +• Change keyword from *CONSTRAINED_BEARING to *ELEMENT_BEARING. +• Enhance explicit to use the implicit inertia relief constraints. This allows +implicit-explicit switching for such problems. +• Add new input options to *CONTROL_IMPLICIT_INERTIA_RELIEF. +◦ user specified number of nodes +◦ user specified list of modes to constrain out. +INTRODUCTION +• Implement *CONSTRAINED_BEAM_IN_SOLID. This feature is basically an +overhauled constraint couping between beams and Lagrangian solids that in- +cludes features that make it more attractive in some cases than *CON- +STRAINED_LAGRANGE_IN_SOLID, for example, in modeling coupling of +rebar in concrete. +• Allow *CONSTRAINED_INTERPOLATION to use node set to define the +independent nodes. +• Add new feature MODEL.GE.10 to *CONSTRAINED_INTERPOLATION_- +SPOTWELD (SPR3). This allows parameters STIFF, ALPHA1, RN, RS, and BE- +TA to be defined as *DEFINE_FUNCTIONs of thicknesses and maximum +engineering yield stresses of connected sheets. +• Add failure reports for *CONSTRAINED_SPR2. +• Add more d3hsp output for *CONSTRAINED_INTERPOLATION_SPOTWELD +and *CONSTRAINED_SPR2. Can be deactivated by setting NPOPT = 1 on +*CONTROL_OUTPUT. +• Add option to *CONSTRAINED_JOINT: Relative penalty stiffness can now be +defined as function of time when RPS < 0 refers to a load curve. Works for +SPHERICAL, REVOLUTE, CYLINDRICAL in explixit analyses. +• Variable MODEL invokes new SPR4 option in *CONSTRAINED_INTERPOLA- +TION_SPOTWELD. +• *CONSTRAINED_JOINT_GEARS: Gear joint now supports bevel gears and +similar types, i.e., the contact point does not necessarily have to be on the axis +between the gear centers. +• *CONSTRAINED_MULTIPLE_GLOBAL: Support multiple constraints defined +on the extra DOFs of user-defined elements. +• Make the *CONTROL_SHELL PSNFAIL option work with the W-MODE +deletion criterion for shells. +• New subcycling scheme activated for *CONTROL_SUBCYCLE and *CON- +TROL_SUBCYCLE_MASS_SCALED_PART. By default the ratio between the +largest and smallest time step is now 16 and the external forces are evaluated +every time step. The old scheme had a hard wired ratio of 8. The ratios can be +optionally changed by *CONTROL_SUBCYCLE_K_L where K is the maximum +ratio between time steps for internal forces and L is likewise the ratio for external +forces. +• *DATABASE_PROFILE: +◦ output kinetic and internal energy profiles, +◦ output volume fraction profiles, +◦ add a parameter MMG to specify the ALE group for which element data +can be output. +INTRODUCTION +• *DATABASE_ALE_MAT: can now use *DEFINE_BOX to compute the material +energies, volumes and masses for elements inside boxes (instead of the whole +mesh). +• *DATABASE_TRACER_GENERATE: new keyword to create ALE tracer +particles along iso-surfaces. +• *DATABASE_FSI: add option to output moments created by FSI forces about +each node in a node set. These moments about nodes are reported in dbfsi. +• Add *DATABASE_BEARING to write brngout data pertaining to *ELEMENT_- +BEARINGs. +• Include eroded hourglass energy in hourglass energy in glstat file to be con- +sistent with KE & IE calculations so that the total energy = kinetic energy + +internal energy + hourglass energy + rigidwall energy. +• Add support for new database pbstat (*DATABASE_PBSTAT) for *PARTICLE_- +BLAST. +◦ internal energy and translational energy of air and detonation products +◦ force/pressure of air and detonation products for each part +• *DATABASE_EXTENT_INTFOR: New parameter NWEAR on optional card +governs the output of wear depth to the intfor database. +• Using CMPFLG = -1 in *DATABASE_EXTENT_BINARY will work just as +CMPFLG = 1, except that for *MAT_FABRIC (form 14 and form -14) and *MAT_- +FABRIC_MAP the local strains and stresses will be engineering quantities in- +stead of Green-Lagrange strain and 2nd Piola-Kirchhoff stress. +• For some materials and elements, thermal and plastic strain tensors can be +output to d3plot database, see STRFLG in *DATABASE_EXTENT_BINARY. +• Add option for output of detailed (or long) warning/error messages to d3msg. +See MSGFLG in *CONTROL_OUTPUT. Only a few "long" versions of warn- +ings/errors at this time but that list is expected to grow. +• Add two new options for rigid body data compression in d3plot; see DCOMP in +*DATABASE_EXTENT_BINARY. +• Add option to write revised legend to jntforc, secforc, rcforc, deforc and nodout +files via input flag NEWLEG in *CONTROL_OUTPUT. This helps to avoid +confusion over unassigned IDs and duplicated IDs. +• If any input data is encrypted and dynain is requested, the code issues an error +message and stops the job. +• Solid part or solid part set is now allowed for *DEFINE_DE_TO_SURFACE_- +COUPLING. +• Implement *DELETE_PART for Discrete Element Sphere. +INTRODUCTION +• The unit of contact angle changed from radian to degree for *CONTROL_DIS- +CRETE_ELEMENT. +• Implement Archard's wear law to *DEFINE_DE_TO_SURFACE_COUPLING for +discrete element spheres. Wear factor is output to DEM binout database. +• Add damping energy and frictional energy of discrete elements to "damping +energy" and "sliding interface energy" terms in glstat. +• Introduce a small perturbation to the initial position of newly generated discrete +elements for *DEFINE_DE_INJECTION. This allows a more random spatial +distribution of the generated particles. +• *INTERFACE_DE_HBOND replaces *INTERFACE_DE_BOND. Used to define +the failure models for bonds linking various discrete element (DE) parts within +one heterogeneous bond definition (*DEFINE_DE_HBOND). +• *DEFINE_ADAPTIVE_SOLID_TO_DES: Embed and/or transform failed solid +elements to DES (*ELEMENT_DISCRETE_SPHERE) particles. The DES particles +inherit the material properties of the solid elements. All DES-based features are +available through this transformation, including the bond models and contact +algorithms. This command is essentially to DES what *DEFINE_ADAPTIVE_- +SOLID_TO_SPH is to SPH particles. +• Add EM orthotropic materials where the electric conductivity is a 3x3 tensor, see +new card, *EM_MAT_003. +• Add new keyword family, *EM_DATABASE_... which triggers the output of EM +quantites and variables. All EM related ASCII outputs now start with em_***. +Keywords are : +◦ EM_DATABASE_CIRCUIT +◦ EM_DATABASE_CIRCUIT0D +◦ EM_DATABASE_ELOUT +◦ EM_DATABASE_GLOBALENERGY +◦ EM_DATABASE_NODOUT +◦ EM_DATABASE_PARTDATA +◦ EM_DATABASE_POINTOUT +◦ EM_DATABASE_ROGO +◦ EM_DATABASE_TIMESTEP +• Add capability to plot magnetic field lines in and around the conductors at given +times, see *EM_DATABASE_FIELDLINE. ASCII output files are generated +(lspp_fieldLine_xx) and are readable by LSPP in order to plot the field lines. In +the future, LSPP will be capable of directly generating the field lines. +• Add EM quantities in *DEFINE_CURVE_FUNCTION: +◦ EM_ELHIST for element history (at element center). +◦ EM_NDHIST for node history. +INTRODUCTION +◦ EM_PAHIST for part history (integrated over the part). +• Add *EM_EOS_TABULATED2 where a load curve defines the electrical +conductivity vs time. +• Introduce capability to use the EM solver on (thin) shells: An underlying solid +mesh (hexes and prisms) is built where the EM is solved and the EM fields are +then collapsed onto the corresponding shell. The EM mat for shells is defined in +*EM_MAT_004. This works for EM solvers 1, 2 and 3 and the EM contact is +available for shells. +• Add different contact options in the *EM_CONTACT card. +• Add new methods to calculate electric contact resistance between two conduc- +tors for Resistive Spot Welding applications (RSW). See *EM_CONTACT_RE- +SISTANCE. +• Add Joule Heating in the contact resistance (*EM_CONTACT_RESISTANCE). +The Joule heating is evenly spread between the elements adjacent to the faces in +contact. +• Add new circuit types 21 and 22 allowing users to put in +their own periodic curve shape when using the inductive heating solver. This is +useful in cases where the current is not a perfect sinusoidal. +• Provide default values for NCYCLEBEM and NCYCLEFEM (=5000) and set +default value of NUMLS to 100 in *EM_CIRCUIT. +• Add two additional formulations, FORM = 3 and 4, to *PART_MODES. +• Add 20-node solid element, ELFORM = 23 in *SECTION_SOLID. +• Add H8TOH20 option to *ELEMENT_SOLID to convert 8-node to 20-node +solids. +• Add option SOLSIG to *CONTROL_OUTPUT which will permit stresses and +other history variables for multi-integration point solids to be extrapolated to +nodes. These extrapolated nodal values replace the integration point values +normally stored in d3plot. NINTSLD must be set to 8 in *DATABASE_EX- +TENT_BINARY when a nonzero SOLSIG is specified. Supported solid formula- +tions are solid elements are: -1, -2, 2, 3, 4, 18, 16, 17, 23. +• Activate contact thickness input from *PART_CONTACT for solids. +• Made many enhancements for *PART_MODES for robustness and MPP +implementation. +• Add new cohesive shell element (elform = 29) for edge-to-edge connectivity +between shells. This element type takes bending into account and supports MPP +and implicit solvers. +• Error terminate with message, STR+1296, if same node is defined multiple times +in *ELEMENT_MASS_MATRIX. +INTRODUCTION +• Add support for negative MAXINT option in *DATABASE_EXTENT_BINARY +for thick shell elements. +• *ELEMENT_TSHELL: Add "BETA" as option for *ELEMENT_TSHELL to +provide an orthotropic material angle for the element. +• Add Rayleigh damping (*DAMPING_PART_STIFFNESS) for triangular shell +element types 3 and 17. +• Add new keyword *ELEMENT_BEAM_SOURCE. Purpose: Define a nodal +source for beam elements. This feature is implemented for truss beam elements +(ELFORM = 3) with material *MAT_001 and for discrete beam elements +(ELFORM = 6) with material *MAT_071. +• Add new option to *DEFINE_ELEMENT_DEATH. New variable IDGRP defines +a group id for simultaneous deletion of elements. +• Convert cohesive solid type 20 and 22 to incremental formulation to properly +handle large rotations. Also use consistent mass. +• Add Smoothed Particle Galerkin (SPG) method for solid analysis (ELFORM = 47) +and corresponding keyword option *SECTION_SOLID_SPG. SPG is a true +particle method in Galerkin formulation that is suitable for severe deformation +problems and damage analysis. +• Enhance *ELEMENT_LANCING by supporting *PARAMETER, *PARAME- +TER_EXPRESSION. +• Add a new feature, *CONTROL_FORMING_TRIMMING, for 2D and 3D +trimming of a 3-layer, sandwich laminate blank via *DEFINE_CURVE_TRIM. +• Add 3D normal trimming of solid elements via *DEFINE_CURVE_TRIM_3D. +• Add new features for solid elements 2D trimming *DEFINE_CURVE_TRIM_- +NEW: +◦ Allow support of arbitrary trimming vector (previously only global z di- +rection was allowed). +◦ Improve trimming algorithm for speed up. +◦ Allow trimming curves to project to either the top or bottom surface. +• Add a new AUTO_CONSTRAINT option to *CONTROL_FORMING_ONESTEP +which is convenient for blank nesting. +• Add new features to *CONTROL_FORMING_SCRAP_FALL. Previously the +user was required to define the trimmed blank properly. Now the blank is +trimmed by the cutting edge of the trim steel, which is defined by a node set and +a moving vector. +• Enhance *CONTROL_FORMING_SCRAP_FALL: Allow the node set (NDSET) +on the trim steel edge to be defined in any order. +• Improve *CONTROL_FORMING_ONESTEP: +INTRODUCTION +◦ Reposition the initial part before unfolding, using the center element nor- +mal. +◦ Add a message showing that the initial unfolding is in process. +• Add 2D trimming for solid elements *DEFINE_CURVE_TRIM_NEW, support +*DEFINE_TRIM_SEED_POINT_COORDINATES. +• Add *CONTROL_FORMING_AUTOCHECK to detect and fix flaws in the mesh +for the rigid body that models the tooling. +• Add new features to *CONTROL_FORMING_UNFLANGING: +◦ The incoming flange mesh will be automatically checked for mesh quality +and bad elements fixed. +◦ Allow thickness offset of deformable flange to use the blank thickness from +user's input. +◦ Allow definition any node ID in the outer boundary of the flange, to speed +up the search when holes are present in the part. +◦ Add a new parameter CHARLEN to limit the search region. +◦ Allow holes to exist in the flange regions. +◦ Output a suggested flange part after unflanging simulation, with the failed +elements deleted from the unflanged part. +◦ Automatically define a node set and constraints for the flange boundary +nodes through the user definition of three nodes. +◦ Add output of forming thickness, effective strain and trim curves after un- +flanging simulation. +• Add a new keyword *CONTROL_FORMING_TRIM to replace *ELEMENT_- +TRIM. +• Add a new keyword: *CONTROL_FORMING_UNFLANGING_OUTPUT: Failed +elements are removed to come up with the trim curves. +• Add new features to *INTERFACE_BLANKSIZE_DEVELOPMENT including +allowing for trimming between initial and final blank. +• Enhance *CONTROL_FORMING_OUTPUT for controlling the number of states. +• Add *CONTROL_FORMING_TRIM_MERGE to close a user specified (gap) +value in the trim curves, so each trim curve will form a closed loop, which is +required for a successful trimming. +• Add *CONTROL_FORMING_MAXID to set a maximum node ID and element +ID for the incoming dynain file (typically the blank) in the current simulation. +• Enhance *FREQUENCY_DOMAIN_ACOUSTIC_BEM: +◦ Update the boundary condition definition for BEM acoustics so that im- +pedance and other user defined boundary conditions can be combined +with time domain velocity boundary condition. +INTRODUCTION +◦ Implement Burton-Miller BEM to MPP. +◦ Implement impedance boundary condition to Burton-Miller BEM. +◦ Implement half space option (*FREQUENCY_DOMAIN_ACOUSTIC_- +BEM_HALF_SPACE) to variational indirect BEM. +◦ Implement half space option to acoustic scattering problems. +◦ Extend acoustic ATV computation to elements, in addition to nodes. +◦ Support element based ATV output in d3atv. +◦ Add an option (_MATV) to run modal acoustic transfer vector. Implement +MATV to MPP. +◦ Implement running BEM Acoustics based on modal ATV (SSD excitation +only). +• *FREQUENCY_DOMAIN_ACOUSTIC_FEM: Enable running FEM acoustics +based on restarting SSD (*FREQUENCY_DOMAIN_SSD). +• Add *FREQUENCY_DOMAIN_ACOUSTIC_INCIDENT_WAVE to define the +incident waves for acoustic scattering problems. To be used with *FREQUEN- +CY_DOMAIN_ACOUSTIC_BEM. +• Add *FREQUENCY_DOMAIN_ACOUSTIC_SOUND_SPEED to define frequen- +cy dependent complex sound speed, which can be used in BEM acoustics. By +using complex sound speed, the damping in the acoustic system can be consid- +ered. To be used with *FREQUENCY_DOMAIN_ACOUSTIC_BEM. +• *FREQUENCY_DOMAIN_FRF: Add mode dependent rayleigh damping to frf +and ssd (DMPMAS and DMPSTF). +• *FREQUENCY_DOMAIN_RESPONSE_SPECTRUM: +◦ Add output of nodout_spcm and elout_spcm, to get nodal results and ele- +ment results at user specified nodes and elements. +◦ Add von Mises stress computation. +• *FREQUENCY_DOMAIN_RANDOM_VIBRATION: Add semi-log, and linear- +linear interpolation on PSD curves (parameter LDFLAG). +• *FREQUENCY_DOMAIN_SSD: +◦ Add strain computation. +◦ Add parameter LC3 to define the duration of excitation for each frequency. +◦ Implement fatigue analysis option (_FATIGUE) based on ssd (sine sweep). +◦ Add option to use *DAMPING_PART_MASS and *DAMPING_PART_- +STIFFNESS in SSD (DMPFLG = 1). +• Add *MAT_ADD_FATIGUE to define material's SN fatigue curve for applica- +tion in vibration fatigue and SSD fatigue analysis. +• Add +*FREQUENCY_DOMAIN_ACCELERATION_UNIT +to +facilitate +the +acceleration unit conversion. +INTRODUCTION +• The icfd_mstats.dat file now outputs the ten worst quality element locations +(ICFD solver). +• Add option in *ICFD_CONTROL_OUTPUT allowing terminal output to be +written to messag file. +• Add keyword *ICFD_CONTROL_OUTPUT_SUBDOM to output only part of the +domain. Available for vtk, dx and gmv formats. +• Add new keyword family, *ICFD_DATABASE_... which triggers the output of +ICFD variables. All ICFD related output files now start with icfd_***. +• Add new keyword family *ICFD_SOLVER_TOL_... which allows the user to +control tolerances and iteration number for the fractional step solve, the mesh +movement solve, and the heat equation solve. +• Curves in *ICFD_BOUNDARY_PRESCRIBED_VEL each provide a scaling factor +vs. x,y, or z coordinate, respectively. These scaling factors are applied to the +velocity boundary condition. +• Enable free-slip condition for FSI walls (ICFD solver). +• Add new variable IDC to *ICFD_CONTROL_FSI that allows the modification of +the scaling parameter that multiplies the mesh size to detect contact. +• Add automatic squeezing to the ICFD elements of the boundary layer when +there are two very close surfaces with poor (coarse) mesh resolution. +• Add the initialization for all nodes using *ICFD_INITIAL with PID = 0. +• Add a curve (LCIDSF in *ICFD_CONTROL_TIME) that scales the CFL number +as a function of time. +• Add a Heaviside function that allows the solution of simple multiphase +problems (ICFD). +• Add the computation of the heat convection coefficient (ICFD). +• Add MPP support for y+ and shear for output (ICFD). +• Add uniformity index (ICFD). +• Add *ICFD_CONTROL_TAVERAGE to control the restarting time for compu- +ting the time average values. +• Implement the XMl format for vtk. See *ICFD_CONTROL_OUTPUT. +• Improve temperature stabilization for thermal problems (ICFD). +• Add the Generalized Flow Through Porous Media model monolithically coupled +to the incompressible Navier-Stokes model. See keyword *ICFD_MAT for the +new options. +• Add the Anisotropic version of the Generalized Flow in Porous Media. See +*ICFD_MAT for details. +INTRODUCTION +• Add the capability to define the porous properties using the Pressure-Velocity +(P-V) experimental curves. See *ICFD_MAT. +• Compute drag forces around anisotropic/isotropic porous domains (ICFD). +• Extend implicit debug checking when LPRINT = 3 on *CONTROL_IMPLICIT_- +SOLVER. +• Add option for implicit dynamic relaxation so that only a subset of parts is active +during the dynamic relaxation phase. +• Extend implicit time step control via IAUTO < 0 in *CONTROL_IMPLICIT_AU- +TO to linear analysis. +• Add self piercing rivet capability to implicit (*CONSTRAINED_SPR2, *CON- +STRAINED_INTERPOLATION_SPOTWELD). +• Add MTXDMP in *CONTROL_IMPLICIT_SOLVER to dump the damping +matrix from implicit mechanics. +• Improve stress and strain computation induced by mode shapes. See MSTRES +in *CONTROL_IMPLICIT_EIGENVALUE. +• Add variable MSTRSCL to *CONTROL_IMPLICIT_EIGENVALUE for user +control of geometry scaling for the stress computation. +• Make SMP and MPP treatment of autospc constraints consistent. See AUTOSPC +on *CONTROL_IMPLICIT_SOLVER. +• Enhance output for *ELEMENT_DIRECT_MATRIX_INPUT (superelements) to +describe how they are attached to the LS-DYNA model. +• Enhance superelement computation (*CONTROL_IMPLICIT_MODES or *CON- +TROL_IMPLICIT_STATIC_CONDENSATION): +◦ The computation of the inertia matrix in the presense of rigid bodies is cor- +rect. +◦ Adjust superelement computation to accept initial velocities. +◦ Add null beams for the visualization of superelements. +• Enhance implicit to allow the use of *CONSTRAINED_RIVET in conjunction +with axisymmetric shell element problems. +• Add output of performance statistics for the MPP implicit eigensolver to +mes0000. +• Add Stress computation to modal dynamics (*CONTROL_IMPLICIT_MODAL_- +DYNAMIC). +• Allow unsymmetric terms to the assembled stiffness matrix from some implicit +features. +INTRODUCTION +• Enhance implicit-explicit switching (IMFLAG < 0 in *CONTROL_IMPLICIT_- +GENERAL) so that curve |IMFLAG| can be defined using *DEFINE_CURVE_- +FUNCTION. +• Upgrade the implicit implementation of rack and pinion and screw joints so the +joint is driven by relative motion of the assembly instead of absolute motion. +• Add *CONTACT_1D to implicit mechanics. +• *CONTROL_IMPLICIT_ROTATIONAL_DYNAMICS +Rotordynamics using the implicit time integrator. +is +added +to +study +• *MAT_SEATBELT is supported for implicit by introducing bending stiffness. +• *INITIAL_LAG_MAPPING added to initialize a 3D Lagrangian mesh from the +last cycle of a 2D Lagrangian simulation. +• *ELEMENT_SHELL_NURBS_PATCH: +◦ Add support for dumping of strain tensor and shell internal energy densi- +ty for isogeometric shells via interpolation shells. +◦ Add conventional mass-scaling for isogeometric shells. +• *LOAD_BODY_POROUS: applies also now to 1D and 2D problems. +• Add *LOAD_SEGMENT_CONTACT_MASK, which currently works in MPP +only. This feature masks the pressure from a *LOAD_SEGMENT_SET when the +pressure segments are in contact with another material. +• Curve LCID of *LOAD_NODE can be defined by *DEFINE_CURVE_FUNC- +TION. +• *USER_LOADING: pass more data to user-defined loading subroutine loadud +including nodal moment, nodal rotational displacement and velocity, and nodal +translational mass and rotational inertia. +• Add load curves for dynamic relaxation for *LOAD_THERMAL_VARIABLE. +• *LOAD_SEGMENT_NONUNIFORM, +*LOAD_SEGMENT_SET_NONUNI- +FORM: By specifying a negative load curve ID the applied load becomes a +follower force, i.e., the direction of the load is constant with respect to a local +coordinate system that rotates with the segment. +• Make several enhancements to *MAT_172. +• *MAT_HYPERELASTIC_RUBBER (*MAT_077_H) has new thermal option for +material properties. +• Add +*MAT_ORTHOTROPIC_PHASE_CHANGE, +*MAT_ELASTIC_PHASE_- +CHANGE, and +• *MAT_MOONEY-RIVLIN_PHASE_CHANGE whereby elements change phase +as they cross a plane in space. +INTRODUCTION +• Add P1DOFF to 2D seatbelt material, *MAT_SEATBELT_2D, to specify a part ID +offset for the internally created 1D seatbelt elements. +• All load curves for *MAT_067 can be defined via *DEFINE_FUNCTION. +• Enhance *MAT_CWM: +◦ Add support for shell elements. +◦ Add support for hardening curves. Yield stress can be supplied as table +depending on plastic strain and temperature. +• Check diagonal elements of C-matrix of *MAT_002/MAT_{OPTION}TROPIC_ +ELASTIC and error terminate with message, STR+1306, if any are negative. +• Add a keyword option called MIDFAIL for *MAT_024, (MAT_PIECEWISE_LIN- +EAR_PLASTICITY). When MIDFAIL appears in the keyword, failure by plastic +strain will only be checked at the mid-plane. If the mid-plane fails, then the +element fails. If there are an even number of integration points through the +thickness, then the two points closest to the middle will check for failure and the +element fails when both layers fail. +• Enable solid and solid assembly spot welds (*MAT_SPOTWELD) to use the NF +parameter for force filtering. +• Add the shear angle in degrees as the first history variable for shell material +*MAT_214 (DRY_FABRIC). +• Expand from 2 to 5 the number of additional cards that can be used for the user +defined weld failure, OPT = 12 or OPT = 22 on *MAT_SPOTWELD. Now a total +of 46 user variables are possible. +• Add a solid spot weld material option in *MAT_SPOTWELD to treat the stress +state as uniaxial. This option is available for solid assemblies also. +• Add *MAT_FABRIC form 24 which is a modified version of form 14. The main +improvement is that the Poisson's effects work correctly with the nonlinear +curves for fiber stress. Also, the output of stress and strain to d3plot are engi- +neering stress and strain instead of 2nd PK stress and Green's strain. Added an +option to input curves in engineering stress and strain rather than 2nd PK stress +vs. Green's strain. To use this, set DATYP = -2 on *DEFINE_CURVE. +• Increase maximum number of plies from 8 to 24 in a sublaminate with *MAT_- +CODAM2. +• Add *MAT_THERMAL_CHEMICAL_REACTION to model a material undergo- +ing a chemical reaction such as an epoxy used in manufacturing composite +materials. +• *MAT_058: +◦ Add option to use nonlinear (elastic) stress-strain curves instead of con- +stant stiffnesses (EA, EB, GAB). +INTRODUCTION +◦ Add option to use strain-rate dependent nonlinear (elastic) stress-strain +curves instead of constant stiffnesses (EA, EB, GAB). +◦ Add option to define proper poisson ratios PRCA and PRCB (also added in +*MAT_158). +• Add option to use yield curve or table in *MAT_100 (*MAT_SPOTWELD) for +solid elements. +• Add *MAT_157 for solid elements. This includes an optional variable IHIS that +invokes *INITIAL_STRESS_SOLID to initialize material properties on an ele- +ment-by-element basis. This was developed to allow a user to map/initialize +anisotropic material properties from an injection molding simulation. +• *MAT_157 (shells): +◦ Add anisotropic scale factor for plastic strain rate (VP = 1 only). +◦ Improve local stress projection for VP = 1. +◦ Add optional variable IHIS, similar to that described for solids above. +• Add strain rate dependence to *MAT_103 for solids via a table (isotropic +hardening only). +• *MAT_136 (*MAT_CORUS_VEGTER): Implemented an alternative, implicit +plasticity algorithm (define N.lt.0) for enhanced stability. +• *MAT_244 (*MAT_UHS_STEEL): +◦ In plasticity with non-linear hardening, temperature effects and strain rate +effects are now dealt with the same way they are implemented in *MAT_- +106. In particular, strain rate now refers to the plastic strain rate. +◦ Allow for the definition of start temperatures for each phase change, for +cooling and heating. +◦ Account for elastic transformation strains, given as a curve wrt tempera- +ture. +◦ Add feature to *MAT_244 for welding simulations. Similar to *MAT_270, +material can be initialized in a quiet (ghost) state and activated at a birth +temperature. +• Furthermore, annealing is accounted for. +• - Modify formula for Pearlite phase kinetics based on Kirkaldy and Venugoplan +(1983). +• +• *MAT_249 +(*MAT_REINFORCED_THERMOPLASTIC): +Implement +new +material formulation for shells, which is based on additive split of stress tensor. +INTRODUCTION +◦ For the thermoplastic matrix, a thermo-elasto-plastic material is imple- +load +temperature dependence +is defined by +mented,where +curves/tables in the input file. +the +◦ Includes hyperelastic fiber contribution. +◦ For any integration point, up to three different fiber directions can be de- +fined. Their (non-linear) response to elongation and shear deformations +can also be defined with load curves. +◦ Includes input parameters for anisotropic transverse shear stiffness. +• *MAT_T07 (*MAT_THERMAL_CWM): Add HBIRTH and TBIRTH which are +specific heat and thermal conductivity, resp., used for time t < TISTART. +• One additional parameter (exponent GAMMA) for B-K law of *MAT_138. +• MAT_187: Speed-up of load curve lookup for curves with many points. +• Add new option "MAGNESIUM" to *MAT_233. Differences between tension +and compression are included. +• Add enhanced damage model with crack closure effects to *MAT_104. +• Some improvements for *MAT_075 (BILKHU/DUBOIS_FOAM): Volumetric +strain rate can now be averaged over NCYCLE cycles, original input curve +LCRATE is instead of a rediscretized curve, and averaged strain rate is stored as +history variable #3. +• Add new history variables to *MAT_123: A mixed failure indicator as history +variable #10 and triaxiality as #11. +• Decrease memory requirements for *MAT_ADD_EROSION by 50%. +• Add *MAT_098 for tetrahedral solid type 13. +• Add new history variable #8 to *MAT_157 for shell elements: "Anisotropic +equivalent plastic strain". +• Add tangent stiffness to *MAT_224 for implicit analyses with solid and shell +elements. +• Put internal enery on "plastic strain" location for *MAT_027 solids. +• Add new option *MAT_224: BETA .LT. 0: strain rate dependent amount given +by load curve ID = -BETA +• Add new flag to switch off all MAT_ADD_EROSION definitions globally. +• This will be the 1st parameter "MAEOFF" on new keyword *CONTROL_MAT. +• Add option to define a load curve for isotropic hardening in *MAT_135. +• *MAT_CDPM is reimplemented by its original developers (Peter Grassl and +Dimitros Xenos at University of Glasgow) for enhanced robustness. A new +parameter EFC is introduced governing damage in compression and the bilinear +law is exchanged for an exponential one. +INTRODUCTION +• *MAT_3-PARAMETER_BARLAT: HR = 7 is complemented with biaxial/shear +hardening curves. +• *MAT_FABRIC_MAP: +◦ A stress map material for detailed stress response in fabrics, stress can be +prescribed through tables PXX and PYY corresponding to functions of bi- +axial strain states. +◦ A compaction effect due to packing of yarns in compression is obtained by +specifying BULKC (bulk modulus) and JACC (critical jacobian for the on- +set of compaction effect). This results ib increasing pressure that resists +membrane elements from collapsing and/or inverting. +◦ Strain rate effects can be obtained by specifying FXX and FYY which in ef- +fect scales the stress based on engineering strain rate. A smoothing effect +is applied by using a time window DT. +◦ A hysteresis option TH is implemented for stability, given in fraction dis- +sipated energy during a cycle. Can also depend on the strain state through +a table. +• *MAT_GENERAL_HYPERELASTIC_RUBBER, +*MAT_OGDEN_RUBBER: By +specifying TBHYS.LT.0 a more intuitive interpolation of the damage vs. devia- +toric strain energy is obtained. It requires however that the damage and strain +energy axes are swapped. +• *MAT_SIMPLIFIED_RUBBER: For AVGOPT.LT.0 the absolute value represents a +time window over which the strain rates are averaged. This is for suppressing +extensive noise used for evaluating stress from tables. +• *MAT_FABRIC: The bending +stiffness +contribution +in material 34, +ECOAT/SCOAT/TCOAT, is now supported in implicit calculations. +• Add *MAT_122_3D which is an extension of *MAT_122 to solid elements. This +material model combines orthotropic elastic behavior with Hill’s 1948 aniso- +tropic plasticity theory and its applicability is primarily to composite materials. +• MPP groupable tied contact: Output messages about initial node movement due +to projection like non-groupable routines do. +• MPP tied contact initialization: +◦ Change a tolerance in groupable tied contact bucketsort to match the non- +groupable code, and fix the slave node thickness used for beam nodes dur- +ing initial search in non-groupable contact to match groupable contact. +◦ Update the slave node from beam thickness calculation for type 9,11, and +12 beams. +• For MPP, set a "last known location" flag to give some indication of where the +processors were if an error termination happens. Each writes a message to their +INTRODUCTION +own message file. Look for a line that says "When error termination was trig- +gered, this processor was". +• MPP BEAMS_TO_SURFACE contact: Remove "beam" node mass from the +penalty stiffness calculation when soft = 1 is used, which matches SMP behavior. +• Make sure the pfile.log file gets created in case of termination due to *CON- +TROL_STRUCTURED_TERM. +• Add two new decomposition region-related pfile options "nproc" and "%proc" so +that any given decomposition region can be assigned to some subset of all the +processors. nproc takes a single argument, which is a specific number of proces- +sors. %proc takes a single argument, which is a percentage of processors to use. +The old options "lump" and "distribute" are still available and are mapped to the +new options thusly: +◦ lump => "nproc 1" +◦ distribute => "%proc 100.0" +• Tweak MPP beam-to-beam contact routine for better handling of parallel beams. +• MPP: Add support for new solid and shell cost routines, invoked with the pfile +option "decomp { newcost }". Will be expanded to include beams, thick shells, +etc. in the future. +• MPP contact: add support for IGAP > 2 added to the SINGLE_SURFACE, AU- +TOMATIC_GENERAL, and *_TO_SURFACE contacts. +• Improve the way MPP computes slave node areas for AUTOMATIC_TIEBREAK +contacts (and other that use areas). This should result in less mesh dependency +in the failure condition of AUTOMATIC_TIEBREAK contacts. +• MPP: synchronize rigid body flags for shared nodes during rigid-to-deformable +switching so that these nodes are handled consistently across processors. +• Add new pfile decomposition region option “partsets”. Takes a list of part sets +(SET_PART) from the keyword input and uses them to define a region. +• Apply decomposition transformation (if defined) to: +◦ *CONTROL_MPP_DECOMPOSITION_PARTS_DISTRIBUTE +◦ *CONTROL_MPP_DECOMPOSITION_PARTSET_DISTRIBUTE +◦ *CONTROL_MPP_DECOMPOSITION_ARRANGE_PARTS. +• Honor TIEDPRJ flag on *CONTROL_CONTACT for MPP groupable tied +interfaces. +• Increase initial search distance in MPP tied contact to include slave and master +thicknesses. +• Tweak MPP_INTERFERENCE contact to better handle deep initial penetrations. +INTRODUCTION +• MPP: Reorganize how *RIGIDWALL_PLANAR_FORCES is handled, which +greatly improves scaling. +• Add new MPP pfile option: directory { local_dirs { path1 path2 path3 } which +will assign different local working directories to different processors, to balance +the I/O load. +• Miscellaneous MPP enhancements: +◦ Restructure and reduce memory usage of 3D ALE searching of neighbor- +ing algorithm. Now, the code can handle hundreds of millions ALE ele- +ments during decomposition. +◦ Support *PARTICLE_BLAST. +◦ Support SPH 2D contact. +◦ Greatly speed up reconstruction of eroding contact surface, (soft = 0,1) +when using large number of cores. +• Add the following options for small restarts: +◦ *CHANGE_VELOCITY_GENERATION, +◦ *CHANGE_RIGIDWALL_option, +◦ PSNFAIL option to *CONTROL_SHELL +• MPP full deck restart: Restore behavior consistent with SMP which is that only +the nodes of materials being initialized (not all nodes) are initialized from d3full. +• MPP: add full deck restart support for AUTOMATIC_TIEBREAK contact types. +• Implement *DELETE_PART for seatbelt parts. The associated slipring, retractors +and pretensioners will be deactivated as well. +• Add support for MPP restarts with USA coupling. +• Add NREP option to *SENSOR_CONTROL to repeat NREP cycles of switches +given on Card 2. +• Implement *SENSOR_CONTROL TYPEs BELTPRET, BELTRETRA and BELT- +SLIP control the pretensioners, retractors and sliprings of a 2D seatbelt. +• Add function SENSORD to *DEFINE_CURVE_FUNCTION to return the value +of a sensor. +• Replace *SENSOR_DEFINE_ANGLE with more general *SENSOR_DEFINE_- +MISC. MTYPEs include ANGLE, RETRACTOR, RIGIDBODY, and TIME. +• Add rcforc output for *CONTACT_2D_NODE_TO_SOLID (supported for ASCII +output only; not binout). +• Add temperature output (when applicable) to sphout file (*DATABASE_SPHO- +UT). +INTRODUCTION +• Add support of *MAT_ALE_VISCOUS for SPH particles. This allows modeling +of non-viscous fluids with constant or variable viscosity, i.e, non-newtonian type +fluid using SPH. +• Add support of *EOS for *MAT_272 with SPH particles. +• Add support of *MAT_255, *MAT_126, and *MAT_26 (with AOPT = 2 only) for +SPH particles. +• Add new keyword command *SECTION_SPH_INTERACTION: Combined with +CONT = 1 in *CONTROL_SPH card, this keyword is used to define the partial +interaction between SPH parts through normal interpolation method and partial +interaction through the contact option. All the SPH parts defined through this +keyword will interact with each other through normal interpolation method +automatically. +• Add support for *DATABASE_TRACER for axisymmetric SPH (IDIM = -2 in +*CONTROL_SPH). +• ICONT in *CONTROL_SPH now affects *DEFINE_SPH_TO_SPH_COUPLING +in the sense of enabling or disabling the coupling for deactivated particles. +• The commands *STOCHASTIC_TBX_PARTICLES and *CHEMISTRY_CON- +TROL_TBX are now available for use (along with the CESE solver) in TBX-based +explosives simulations. +• Multi-nozzle injection mode is implemented for spray injection. +• Add logic to skip thermal computations during dynamic relaxation for a coupled +thermal-structual problem (i.e. when SOLN = 2 on the *CONTROL_SOLUTION +keyword). This does not affect the use of *LOAD_THERMAL keywords during +dynamic relaxation. +• Implement *DEFINE_CURVE_FUNCTION +for convection, +flux, radiation +boundary +• conditions in thermal-only analyses, both 2D and 3D. +• *BOUNDARY_CONVECTION, *BOUNDARY_FLUX, and thermal dynamics are +implemented for 20 node brick element. +• Include the reading of thermal data to *INCLUDE_BINARY. +• Allow *DEFINE_FUNCTION_TABULATED to be used in any place that requires +a function of 1 variable. Specifically, as a displacement scale factor with *INTER- +FACE_LINKING_NODE. +• Add new MUTABLE option for *PARAMETER and *PARAMETER_EXPRES- +SION to indicate that it is OK to redefine a specific parameter even if *PARAME- +TER_DUPLICATION says redefinition is not allowed. Also, only honor the first +*PARAMETER_DUPLICATION card. +INTRODUCTION +• Add functions DELAY and PIDCTL to *DEFINE_CURVE_FUNCTION for +simulating PID (proportional-integral-derivative) controllers. +• *DEFINE_TABLE: Add check of table's curves for mismatching origin or end +points. +• Update ANSYS library to version 16.0. +• Enhance report of "Elapsed time" in d3hsp. +• Add keyword *INCLUDE_UNITCELL to create a keyword file containing user- +defined unit cell information with periodic boundary conditions. +• Add *INCLUDE_AUTO_OFFSET: the node and element IDs of the include file +will be checked against IDs of the previously read data to see if there is any +duplication. If duplicates are found, they will be replaced with another unique +ID. +Capabilities added to create LS-DYNA R9.0: +See release notes (published separately) for further details. +• *AIRBAG +◦ Disable CPM airbag feature during DR and reactivate in the transient +phase. +◦ *AIRBAG_WANG_NEFSKE_POP_ID pop venting based on RBIDP is now +supported correctly (MPP only). +◦ *AIRBAG_INTERACTION: + Fixed MPP airbag data sync error to allow final pressure among in- +teracted airbags to reach equilibrium. +◦ *AIRBAG_PARTICLE: + When IAR = -1 and Pbag or Pchamber is lower than Patm, ambient +air will inflate the bag through external vents and also fabric porosity. + Treat heat convection when chamber is defined. + Output pres+ and pres- to CPM interface forces file for internal parts. + Allow IAIR = 4 to gradually switch to IAIR = 2 to avoid instability. + Allow using shell to define inflator orifice. The shell center and nor- +mal will be used as orifice node and flow vector direction. + Bug fix for porous leakage for internal fabric parts using CPM. + New feature to collect all ring vents into a single vent in order to cor- +rectly treat enhanced venting option. All the vent data will only be +output to the first part defined in the part set. +INTRODUCTION + Evaluate airbag volume based on relative position to avoid trunca- +tion. The bag volume becomes independent of coordinate transfor- +mation. + Support explicit/implicit switch and dynamic relaxation +for +*AIRBAG_PARTICLE. + Support vent/fabric blockage for CPM and ALE coupled analysis. + New option in *CONTROL_CPM to allow user defined smoothing of +impact forces. + Fixed bug affecting *AIRBAG_PARTICLE_ID with PGP encryption. +• *ALE +◦ *ALE_REFERENCE_SYSTEM_GROUP: For prtype = 4, allow the ALE +mesh to follow the center of mass of a set of nodes. +◦ *CONTROL_ALE: + Add a variable DTMUFAC to control the time step related to the vis- +cosity from + *MAT_NULL (if zero, the viscosity does not control the time step). + Implement a 2D version of BFAC and CFAC smoothing algorithm. +◦ *ALE_SMOOTHING: Automatically generate the list of 3 nodes for the +smoothing constraints and implement for MPP. +◦ *SECTION_ALE2D, *SECTION_SOLID_ALE: Allow a local smoothing +controlled by AFAC,...,DFAC. +◦ *ALE_SWITCH_MMG: Allow the variables to be modified at the time of +the switch. +◦ *CONTROL_REFINE_ALE: Add a variable to delay the refinement after +removal (DELAYRGN), one to delay the removal after the refinement +(DELAYRMV), and one to prevent any removal in a certain radius around +latest refinements (RADIUSRMV). +◦ *ALE_STRUCTURED_MESH: Implemented structured ALE mesh solver to +facilitate rectilinear mesh generation and to run faster. +• *BOUNDARY +◦ *BOUNDARY_AMBIENT_EOS: +Implement +*DEFINE_CURVE_ +FUNCTION for the internal energy and relative volume curves. +◦ *BOUNDARY_AMBIENT: Apply ambient conditions to element sets. +◦ Fix for adaptivity dropping SPCs in some cases (MPP only). +◦ Added conflict error checking between rigid body rotational constraints +(*CONSTRAINED_JOINT) with +joints between +rigid bodies +and +*BOUNDARY_PRESCRIBED_ORIENTATION. +◦ The first rigid body of the prescribed orientation cannot have any rotation- +al constraints. Only spherical joints or translational motors can be used be- +tween the two rigid bodies of the prescribed orientation. For now explicit +INTRODUCTION +will be allowed to continue with these as warnings.Implicit will terminate +at end of input checking. +◦ Instead of error terminating with warning message, STR+1371, when +*BOUNDARY_PRESCRIBED_MOTION and *BOUNDARY_SPC are ap- +plied to same node and dof, issue warning message, KEY+1106, and re- +lease the conflicting SPC. +◦ Fix erroneous results if *SET_BOX option is used for *BOUNDARY_ +PRESCRIBED_MOTION. +◦ Fix *BOUNDARY_PRESCRIBED_ACCELEROMETER_RIGID for MPP. It +may error terminate or give wrong results if more than one of this key- +word are used. +◦ Fix +segmentation +fault when using +*BOUNDARY_PRESCRIBED_ +ORIENTATION with vad = 2, i.e. cubic spline interpolation. +◦ Fix +incorrect behavior +PLANE, i.e. > 1, are used. +if multiple *BOUNDARY_SPC_SYMMETRY_ +◦ Fix incorrect motion if *BOUNDARY_PRESCRIBED_MOTION_RIGID_ +LOCAL is on a rigid part which is merged with a deformable part that has +been switched to rigid using *DEFORMABLE_TO_RIGID. +◦ Fix incorrect external work when using *BOUNDARY_PRESCRIBED_ +MOTION with or without_RIGID option. The dof specified in *BPM was +not considered when computing the external work. Also, when multiple +*BPM applied to the same node/rigid body with different dof may also +cause incorrect computation of external work. +incorrect velocities when using +*BOUNDARY_PRESCRIBED_ +MOTION_RIGID_LOCAL and *INITIAL_VELOCITY_RIGID_BODY for +rigid bodies. +◦ Fix +◦ Implement check for cases where *MAT_ACOUSTIC nodes are merged +with structural nodes on both sides of a plate element and direct the user +to the proper approach to this situation - *BOUNDARY_ACOUSTIC_ +COUPLING. +◦ *BOUNDARY_ACOUSTIC_COUPLING with unmerged, coincident node +coupling now implemented in MPP. +◦ MPP +logic +corrected +so +*MAT_ACOUSTIC and +*BOUNDARY_ +ACOUSTIC_COUPLING features may be used with 1 MPP processor. +◦ Fixed bug for *BOUNDARY_PRESCRIBED_MOTION if part label option +is used. +• BLAST +◦ Improve *LOAD_BLAST_ENHANCED used with ALEPID option in +*LOAD_BLAST_SEGMENT: +◦ Rearrange the ambient element type 5 and its adjacent element into same +processor to avoid communications. +◦ Eliminate several n-by-n searches for segment set and ambient type 5 with +its neighboring elements to speed up the initialization. +INTRODUCTION +◦ Change +the name of keyword *DEFINE_PBLAST_GEOMETRY +to +*DEFINE_PBLAST_HEGEO. Both names will be recognized. +• *CESE (Compressible Flow Solver) +◦ Modified the CESE moving mesh CHT interface condition calculation to +deal with some occasional MPP failures that could occur with mesh corner +elements. +◦ Improved the CESE spatial derivatives approximation in order to bring +better stability to the CESE solvers. +◦ The 3D SMP and MPP CESE immersed boundary solvers now work with +structural element erosion. +◦ A new energy conservative conjugate heat transfer method has been added +to the following 2D and 3D CESE Navier-Stokes equation solvers: + Fixed mesh (requires use of *CESE_BOUNDARY_CONJ_HEAT input +cards) + Moving mesh FSI + Immersed boundary FSI +◦ Prevent the fluid thermal calculation from using too short a distance be- +tween the fluid and structure points in the new IBM CHT solvers. +◦ In the under resolved situation, prevent the CHT interface temperature +from dipping below the local structural node temperature. +◦ Add detection of blast wave arrival at CESE boundary condition face first +sensing the leading edge of the pulse (used with *LOAD_BLAST_ +ENHANCED). +◦ Set CESE state variable derivatives to more stable values for the blast wave +boundary condition. +◦ Corrected time step handling for the CESE Eulerian conjugate-heat transfer +solver. This affected only the reported output time. +◦ Added CESE cyclic BC capability to the moving mesh CESE solver. +◦ Fixed some issues with 2D CESE solvers where the mesh is created via +*MESH cards. +◦ For the CESE solver coupled with the structural solver (FSI), corrected the +time step handling. +◦ For the CESE mesh motion solvers, and the ICFD implicit ball-vertex mesh +motion solver, added a mechanism to check if all of the imposed boundary +displacements are so small that it is not necessary to actually invoke the +mesh motion solver. This is determined by comparing the magnitude of +the imposed displacement at a node with the minimum distance to a virtu- +al ball vertex (that would appear in the ball-vertex method). The relative +scale for this check can be input by the user via field 4 of the *CESE_ +CONTROL_MESH_MOV card. +INTRODUCTION +◦ Changed the NaN check capability for the CESE solvers to be activated on- +ly upon user request. This is input via a non-zero entry in field 7 of the +*CESE_CONTROL_SOLVER card. +◦ Much like the ICFD solver, added a mechanism to adjust the distance used +by the contact detection algorithm for the *CESE_BOUNDARY_FSI cards, +as well as the new moving mesh conjugate heat transfer solvers. This is +available through field 6 of the *CESE_CONTROL_SOLVER card. +◦ Added a correction to the moving mesh CESE solver geometry calculation. +◦ Corrected the initial time step calculation for both the 2D and 3D moving +mesh CESE solvers. +◦ For the moving mesh CESE solver, replaced the all-to-all communication +for fsi quantities with a sparse communication mechanism. +• *CHEMISTRY +◦ The immersed boundary FSI method coupled with the chemistry solver is +released. + Only Euler solvers, both in 2D and 3D, are completed with full chem- +istry. + Using this technique, CESE FSI Immerged Boundary Method coupled +to the chemistry solver can be applied to high speed combustion +problems such as explosion, detonation shock interacting with struc- +tures, and so on. + Some examples are available on our ftp site. +• *CONTACT +◦ Fix MPP groupable contact problem that could in some cases have oriented +the contact surfaces inconsistently. +◦ Fix bug in *CONTACT_AUTOMATIC_SURFACE_TO_SURFACE_TIED_ +WELD. +◦ Fix seg fault when using *CONTACT_AUTOMATIC_SINGLE_SURFACE_ +TIED with consistency mode, .i.e. ncpu < 0, for SMP. +◦ Fix false warnings, SOL+1253, for untied nodes using *CONTACT_ +AUTOMATIC_SURFACE_TO_SURFACE_TIEBREAK and *CONTACT_ +AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE_TIEBREAK. +◦ Fix *CONTACT_TIED_SHELL_EDGE_TO_SURFACE when rigid nodes +are not tied even when ipback = 1. This applies to SMP only. +◦ Issue warning if SOFT = 4 is used with an unsupported contact type, and +reset it to 1. +◦ Change "Interface Pressure" report in intfor file from abs(force/area) to - +force/area, which gives the proper sign in case of a tied interface in ten- +sion. +INTRODUCTION +◦ Increase MPP contact release condition for shell nodes that contact solid +elements in SINGLE_SURFACE contact. +◦ Fix for MPP IPBACK option for creating a backup penalty-based tied con- +tact. +◦ Fix for MPP orthotropic friction in contact. +◦ Fix for MPP *CONTACT_SLIDING_ONLY that was falsely detecting con- +tact in some cases. +◦ Skip constraint based contacts when computing the stable contact time step +size. +◦ Add error trap if node set is input for slave side of single surface contact. +◦ MPP: some fixes for constrained tied contact when used with adaptivity. +The behavior of the slave nodes in adaptive constraints was not correct if +they were also master nodes of a tied interface. This has been fixed, and +support for the rotations required for CONTACT_SPOTWELD have also +been added. +◦ MPP: update to AUTOMATIC_TIEBREAK option 5 to release the slave +nodes (and report them as having failed) when the damage curve reaches +0. +◦ Fix made to routine that determines the contact interface segments, which +was not handling pentahedral thick shell elements correctly. +◦ MPP: fix for strange deadlock that could happen if a user defines a +*CONTACT_FORCE_TRANSDUCER that has no elements in it and so gets +deleted. +◦ MPP contact: add support for *DEFINE_REGION to define an active con- +tact region. Contact occurring outside this region is ignored. This is only +for MPP contact types: + AUTOMATIC_SINGLE_SURFACE + AUTOMATIC_NODES_TO_SURFACE + AUTOMATIC_SURFACE_TO_SURFACE + AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE +◦ MPP fix for table based friction in non-groupable contact. +◦ MPP: add frictional work calculation for beams +in *CONTACT_ +AUTOMATIC_GENERAL. +◦ Added new option "FTORQ" for contact. Currently implemented only for +beams in *CONTACT_AUTOMATIC_GENERAL in MPP. Apply torque to +the nodes to compensate for the torque introduced by friction. Issue error +message when users try to use SOFT = 2/DEPTH = 45 contact for solid el- +ements. +◦ R-adaptivity, ADPOPT = 7 in *CONTROL_ADAPTIVE, is now available +for SMP version of *CONTACT_SURFACE_TO_SURFACE,_NODES_TO_ +SURFACE,_AUTOMATIC_SURFACE_TO_SURFACE, +and_ +AUTOMATIC_NODES_TO_SURFACE (SOFT = 0 or 1 only). +INTRODUCTION +◦ The options AUTOMATIC_SURFACE_TO_SURFACE_COMPOSITE has +been added to model composite processing. The same option may be used +to model certain types of lubrication, and AUTOMATIC_SURFACE_TO_ +SURFACE_LUBRICATION may be used instead of the COMPOSITE op- +tion for clarity. (The two keyword commands are equivalent.) +◦ Added AUTOMATIC_SURFACE_TO_SURFACE_TIED_WELD to model +the simulation of welding. As regions of the surfaces are heated to the +welding temperature and come into contact, the nodes are tied. +◦ Added +*CONTACT_TIED_SHELL_EDGE_TO_SOLID. + This contact +transmits the shell moments into the solid elements by using forces unlike +the SHELL_EDGE_TO_SURFACE contact with solid elements. This capa- +bility is easier for users than *CONSTRAINED_SHELL_TO_SOLID. The +input is identical to *CONTACT_TIED_SHELL_EDGE_TO_SURFACE (ex- +cept for the keyword). +◦ Fix incorrect motion of displayed rigidwall between 0.0 < time < birth_time +when birth time > 0.0 for *RIGIDWALL_GEOMETRIC_FLAT_MOTION_ +DISPLAY. The analysis was still correct. Only the displayed motion of the +rigidwall is incorrect. +◦ Fix corrupted +intfor when using parts/part sets +in *CONTACT_ +AUTOMATIC_.... This affects SMP only. +◦ Fix incorrect stonewall energy when using *RIGIDWALL_PLANAR_ +ORTHO. +◦ Fix unconstrained nodes when using *CONTACT_TIED_SURFACE_TO_ +in warning message, +SURFACE_CONSTRAINED_OFFSET resulting +SOL+540. This affects SMP only. +◦ Fix spurious repositioning of nodes when using *CONTACT_SURFACE_ +TO_SURFACE for SMP. +◦ Enable MAXPAR from optional card A to be used in *CONTACT_TIED_ +SURFACE_TO_SURFACE. It was originally hard-coded to 1.07. +◦ The shells used for visualisation of *RIGIDWALL_PLANAR_MOVING_ +DISPLAY and *RIGIDWALL_PLANAR_MOVING_DISPLAY in d3plot +were not moving with the rigidwall. This is now fixed. +◦ Fix +incorrect +frictional +forces +if_ORTHO_FRICTION +is used +in +*CONTACT_AUTOMATIC_SURFACE_TO_SURFACE. +◦ Fix seg fault when using *CONTACT_ENTITY and output to intfor file +with MPP, i.e. s = intfor in command line. +◦ Fix ineffective birth time for *CONTACT_TIED_NODES_TO_SURFACE. +◦ Fix untied contacts when using *CONTACT_TIED... + with *MAT_ +ANISOTROPIC_ELASTIC_PLASTIC/*MAT_157. +◦ Fix MPP hang up when using *CONTACT_ENTITY. +◦ Allow *CONTACT_AUTOMATIC_GENERAL to use MAXPAR from con- +tact optional card A instead of using the hard coded value of 1.02. This +will better detect end to end contact of beams. This applies to SMP only. +◦ Fix *CONTACT_TIED_SHELL_EDGE_TO_SURFACE for SMP which ig- +nores MAXPAR in contact optional card A. +INTRODUCTION +◦ Fix seg fault when using *CONTACT_GUIDED_CABLE. +◦ Fix segmentation fault when using *CONTACT_AUTOMATIC_SINGLE_ +SURFACE_TIED in consistency mode, i.e. ncpu < 0 in command line, for +SMP. +◦ Fix incorrect contacts when using *CONTACT_AUTOMATIC_GENERAL_ +INTERIOR for beams with large differences in thickness and when the +thinner beams are closer to each other than to the thicker beams. Affects +SMP only. +◦ Fixed force transducers with MPP segment based contact when segments +are involved with multiple 2 surface force transducers. The symptom was +that some forces were missed for contact between segments on different +partitions. +◦ Fixed an MPP problem in segment based contact that cased a divide by ze- +ro during the bucket sort. During an iteration of the bucket sort, all active +segments were somehow in one plane which was far from the origin such +that a dimension rounded to zero. The fix for this should effect only this +rare case and have no effect on most models. +◦ Fixed thermal MPP segment based contact. The message passing of ther- +mal energy due to friction was being skipped unless peak force data was +written to the intfor file. +◦ Fixed MPP segment based implicit contact. A flaw in data handling +caused possible memory errors during a line search. +◦ Fixed implicit dynamic friction for segment based contact. For sliding fric- +tion, the implicit stiffness was reduced to an infinitesimal value. Also, the +viscous damping coefficient is now supported for implicit dynamic solu- +tions. +◦ Fixed segment based contact when the data has all deformable parts that +are switched to rigid at the start of the calculation and then switched back +to deformable prior to contact occurring. A flaw was causing contact to be +too soft. This is now corrected. +◦ Fixed a flaw in segment based contact with DEPTH = 25 that could allow +penetration to occur. +◦ Improved edge-to-edge contact checking (DEPTH = 5,25,35) and the slid- +ing option (SBOPT = 4,5) in areas where bricks have eroded when using +segment based eroding contact. +◦ Improved the initial penetration check (IGNORE = 2 on *CONTROL_ +CONTACT) of segment based contact to eliminate false positives for shell +segments. Previously, the search was done using mid-plane nodes and the +gap or penetration adjusted to account for segment thicknesses after. The +new way projects the nodes to the surface first and uses the projected sur- +face to measure penetration. For brick segments with zero thickness there +should be no difference. For shell segments, the improved accuracy will +me more noticeable for thicker segments. +◦ Improved segment based contact when SHAREC = 1 to run faster when +there are rigid bodies in the contact interface. +INTRODUCTION +◦ Fixed a possible problem during initialization of segment based contact. +Options that use neighbor segment data such as the sliding option and +edge-to-edge checking could access bad data if the same nodes were part +of both the slave and master surfaces. This would not be a normal occur- +rence, but could happen. +◦ Updated segment based contact to improve accuracy at points away from +the origin. The final calculations are now done with nodal and segment lo- +cations that have been shifted towards the origin so that coordinate values +are small. +◦ The reporting of initial penetrations and periodic intersection reports by +segment based contact was corrected for MPP solutions which were report- +ing incorrect element numbers. +◦ Fixed memory errors in 2D automatic contact initialization when friction is +used. +◦ Fixed 2D force transducers in the MPP version which could fail to report +master surface forces. Also fixed 2 surface 2D force transducers when the +smp parallel consistency option is active. +◦ Fixed +*CONTACT_2D_AUTOMAITC_SINGLE_SURFACE and SUR- +FACE_TO_SURFACE which could exhibit unpredictable behavior such as +a force spike or penetration. +◦ Fixed a serious MPP error in the sliding option of *CONTACT_2D_ +AUTOMATIC that could lead to error termination. +◦ Fixed a problem with birth time for *CONTACT_2D_AUTOMATIC_TIED +when used with sensor switching. Also, fixed a problem in the contact en- +ergy calculation that could lead to abnormal terminations. Finally, I made +the process of searching for nodes to tie more robust as some problem was +found with nodes being missed. +◦ Fixed a 2D automatic contact bug that occurred if a segment had zero +length. An infinite thickness value was calculated by A/L causing the +bucket sort to fail. +◦ Added support for *CONTACT_ADD_WEAR for smp and mpp segment +based (SOFT = 2) contact. This option enables wear and sliding distance to +be measured and output to the intfor file. +◦ Added support to segment based contact for the SRNDE parameter on op- +tional card E of *CONTACT. +◦ Added support to segment based eroding contact for SBOXID and MBOX- +ID on card 1 of *CONTACT. +◦ Added support for *ELEMENT_SOURCE_SINK used with segment based +contact. With this update, inactive elements are no longer checked for con- +tact. +◦ Added a segment based contact option to allow the PSTIFF option on +*CONTROL_CONTACT to be specified for individual contact definitions. +The new parameter is PSTIFF on *CONTACT on optional card F, field 1. +Prior to this change, setting PSTIFF on *CONTROL_CONTACT set all con- +tact to use the alternate penalty stiffness method. With this update, PSTIFF +INTRODUCTION +on *CONTROL_CONTACT now sets a default value, and PSTIFF on card F +can be used to override the default value for an individual contact inter- +face. +◦ Added support for REGION option on optional card E of *CONTACT +when using segment based, SOFT = 2 contact. This works for all support- +ed keywords, SMP and MPP. +◦ Added master side output in the MPP version for 2-surface force transduc- +ers when used with segment based (soft = 2) contact. +◦ Added contact friction energy to the sleout database file for + _2D_AUTOMATIC_SURFACE_TO_SURFACE and + _2D_AUTOMATIC_SINGLE_SURFACE contact. +◦ Enabled segment based contact (SMP and MPP) to work with type 24 (27- +node) solid elements. +◦ Enabled the ICOR parameter on *CONTACT, optional card E to be used +with segment based (SOFT = 2) contact. +◦ Fixed output to d3hsp for *CONTACT_DRAWBEAD using negative curve +ID for LCIDRF +◦ Add slave node thickness and master segment thickness as input argu- +ments to the *USER_INTERFACE_FRICTION subroutine usrfrc (SMP). +◦ Forming mortar contact can now run with deformable solid tools and hon- +ors ADPENE to account for curvatures and penetrations in adaptive step. +This applies to h- as well as r-adaptivity. +◦ Single surface and surface-to-surface mortar contact accounts for rotational +degrees of freedom when contact with beam elements. This allows for +beams to "roll" on surfaces and prevents spurious friction energy to be +generated when in contact with rotating parts. +◦ Maximum allowable penetration in forming and automatic mortar contacts +is hereforth .5*(tslav+tmast)*factor where tmast = thickness of slave seg- +ment and tmast = thickness of master segment. The factor is hardwired to +0.95, but is subject to change. Prior to this it was .5*tslav, which seems in- +adequate (too small) in coping with initial penetrations in automotive ap- +plications using standard modeling approaches. +◦ Up to now, mortar contact has only acted between flat surfaces, now ac- +count is taken for sharp edges in solid elements (the angle must initially be +larger than 60 degrees), may have to increase the corresponding stiffness in +the future. +◦ When solid elements are involved in mortar contact the default stiffness is +increased by a factor of 10. This is based on feedback from customers indi- +cating that the contact behavior in those cases has in general been too soft. +This may change the convergence characteristics in implicit but the results +should be an improvement from earlier versions. +◦ The OPTT parameter on *PART_CONTACT for the contact thickness of +beams is now supported in mortar contact. +INTRODUCTION +◦ *CONTACT_ADD_WEAR: A wear law, Archard's or a user defined, can be +associated with a contact interface to assess wear in contact. By specifying +WTYPE < 0 a user defined wear subroutine must be written to customize +the wear law. For the Archard's wear law, parameters can depend on con- +tact pressure, relative sliding velocity and temperature. Contacts support- +ed are *CONTACT_FORMING_SURFACE_TO_SURFACE, *CONTACT_ +FORMING_ONE_WAY_TO_SURFACE and *CONTACT_AUTOMATIC_ +SURFACE_TO_SURFACE. To output wear data set NWEAR = 1 or +NWEAR = 2 on *DATABASE_EXTENT_INTFOR. If NWEAR is set to 2 +then the sliding distance is output to the intfor file, in addition to the wear +depth. Otherwise only wear depth is output. Also, the parameter NWUSR +specifies the number of user wear history variables to be output in case a +user defined wear routine is used. By specifying CID (contact interface id) +to a negative number, the wear depth will couple to the contact in the sim- +ulation in the sense that the penetration is reduced with wear. The effect is +that contact pressure will be redistributed accordingly but is only valid for +relatively small wear depths. A formulation for larger wear depths lie in +the future which will require modification of the actual geometry. +◦ Fixed bug affecting *CONTACT_RIGID_NODE_SURFACE (broken at rev. +86847). The bug was in reading *NODE_RIGID_SURFACE. +◦ A bug fix in *CONTACT_DRAWBEAD_INITILIZE. - The bug was caused +by a sudden increase in effective strain after the element passed the draw- +bead. When the increase in strain is too big, the search algorithm was not +working reasonably in the material routine. At the drawbead intersection +point, an element could be initialized twice by two bead curves, and cause +abnormal thickness distribution. +in +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_ +SURFACE_SMOOTH which removes the limitation that the contact must +be defined by segment set. +◦ Fix a bug +◦ SMOOTH option does not apply to FORMING_SURFACE_TO_SURFACE +contact. When the SMOOTH option is used, we now write a warning mes- +sage and disregard the SMOOTH option. +• *CONSTRAINED +◦ *CONSTRAINED_LAGRANGE_IN_SOLID: +Implement +*CONSTRAINED_LAGRANGE_IN_SOLID_EDGE in 2D. +◦ Fixed bug in *DAMPING_RELATIVE. If the rigid part PIDRB is the slave +part in *CONSTRAINED_RIGID_BODIES, the damping card did not work +correctly. There is a work-around for previous LS-DYNA versions: set +PIDRB to the master part in *CONSTRAIEND_RIGID_BODIES, not the +slave part. +◦ *CONSTRAINED_RIGID_BODY_INSERT: This keyword is for modeling +die inserts. One rigid body, called slave rigid body, is constrained to move +INTRODUCTION +with another rigid body, called the master rigid body, in all directions ex- +cept for one. +◦ A variety of enhancements for *CONSTRAINED_INTERPOLATION. + Enhanced the error message when nodes involved in the constraint +have been deleted. +for +row + Removed printing of 0 node ID in MPP. + Added a warning if there are too many (now set at 1000) nonzeroes in +a constraint +*CONSTRAINED_INTERPOLATION or +*CONSTRAINED_LINEAR to protect implicit's constraint processing. +These constraints will be processed differently in future releases. We +modified the constraint processing software to robustly handle con- +straint rows with thousands of nonzero entries. We added error +checking for co-linear independent nodes as these constraints allow +singularities in the model. +◦ Improved implicit's treatment of the constraints for *CONSTRAINED_ +BEAM_IN_SOLID. +◦ Added error checking on the values of the gear ratios in *CONSTRAINED_ +JOINTS. +◦ *CONSTRAINED_BEAM_IN_SOLID: + Thick shell elements supported. + Wedge elements supported. + Debonding +law by user-defined subroutine (set variable AX- +FOR > 1000). + Debonding law by *DEFINE_FUNCTION (set variable AXFOR < 0). +◦ Error terminate with message, SOL+700, if CIDA and CIDB is not defined +for *CONSTRAINED_JOINT_STIFFNESS_GENERALIZED. +◦ Fix incorrect constraints on rotary dof for adaptivity. +◦ Fix +incorrect motion +in *DEFORMABLE_TO_RIGID_ +AUTOMATIC and if any of the *CONSTRAINED_NODAL_RIGID_BODY +nodes belongs to a solid element. +if NRBF = 2 +◦ Fix input error when using large load curve ID for FMPH, FMT, FMPS in +card 3 of *CONSTRAINED_JOINT_STIFFNESS with_GENERALIZED or_ +TRANSLATIONAL options. +◦ Fix seg fault if using tables for FMPH of *CONSTRAINED_JOINT_ +STIFFNESS and if the angle of rotation is less than the the abscissa of the +table or load curves. +◦ Fixed an problem with *CONSTRAINED_BEAM_IN_SOLID when used in +a model that also uses segment based eroding contact in the MPP version. +This combination now works. +INTRODUCTION +◦ Improved the precision of spot weld constraints (*CONSTRAINED_ +SPOTWELD) to prevent possible divide by zeroes when the inertia tensor +is inverted. This affects the single precision version only. +◦ Fix +for damage +SPOTWELD, MODEL = 2. +function +in +*CONSTRAINED_INTERPOLATION_ +◦ Add some user-friendly output +(rigid body +id) +to d3hsp +for +*CONSTRAINED_NODAL_RIGID_BODY_INERTIA. +◦ Add new option to *CONSTRAINED_SPR2 to connect up to 6 shell ele- +ment parts (metal sheets) with only one rivet location node. This is in- +voked by defining extra part IDs for such a multi-sheet connection. +◦ Add more flexibility to *CONSTRAINED_SPR2: Load curve function ex- +ponent values originally hardwired as "8" can now be defined with new +input parameters EXPN and EXPT. +◦ Fixed bug wherein the joint ID in *CONSTRAINED_JOINT_COOR was +read incorrectly. +◦ Fixed duplicate ID for *CONSTRAINED_SPOTWELD, ..._NODE_SET,_ +POINTS and_SPR2. +◦ Fix keyword +SPR4 +INTERPOLATION_SPOTWELD, where BETA2 was replaced by BETA3. +◦ Significantly reduce the memory demand in the initialization stage of +*CONSTRAINED_ +option +reader +for +in +*CONSTRAINED_MULTIPLE_GLOBAL for implicit analysis. +◦ The unit cell mesh and constraint generated by *INCLUDE_UNITCELL +now supports job ID. +• *CONTROL +◦ Terminate and print error KEY+1117 for cases that use *INCLUDE_ +TRANSFORM in 3d r-adaptvity. More work is needed to make this com- +bination work. +◦ Changed SOL+41 message ("reached minimum step") from an error to a +warning and terminate normally. This message is triggered when the +DTMIN criterion set in *CONTROL_TERMINATION is reached. +◦ Fixed bug in which h-adaptivity missed some ADPFREQ-based adapta- +tions when IREFLG < 0 (*CONTROL_ADAPTIVE). +◦ Fixed bug: MS1ST in *CONTROL_TIMESTEP causes non-physical large +mass and inertia on Nodal Rigid Bodies if Dynamic Relaxation is active. +The error occurs at the start of the transient solution. The mass can become +very large, so the model may appear to be over-restrained. +◦ Add new input check for curves. After rediscretizing curves, check to see +how well the original values can be reproduced. If the match is poor, write +out See variable CDETOL in *CONTROL_OUTPUT. +◦ Added the ability to specify unique values LCINT for each curve, which +override the value set in *CONTROL_SOLUTION. Note: the largest value +of LCINT that appears will be used when allocating memory for each load +INTRODUCTION +curve, so a single large value can cause significant increases in the memory +required for solution. +◦ The DELFR flag in *CONTROL_SHELL has new options for controlling the +deletion of shell elements. This feature is aimed at eliminating single, de- +tached elements and/or elements hanging on by one shared node. +◦ Fix spurious deletion of elements when using TSMIN.ne.0.0 +in +*CONTROL_TERMINATION, ERODE = 1 in *CONTROL_TIMESTEP and +initialized implicitly in dynamic relaxation. +◦ Fix spurious error, STR+755, if using *DAMPING_FREQUENCY_RANGE +with *CONTROL_ADAPTIVE. +◦ Add new feature to *CONTROL_SOLUTION, LCACC, to truncate load +curve to 6 significant figures for single precision & 13 significant figures for +double precision. The truncation is done after applying the offset and scale +factors. +◦ Fix "*** termination due to mass increase ***' error when using mass scal- +ing with *ELEMENT_MASS_PART. +◦ Fix input error 'node set for nodal rigid body # not found' when using +*PART_INERTIA with *CONTROL_SUBCYCLE. +◦ Fixed the negative DT2MS option on *CONTROL_TIMESTEP for thick +shell types 5, 6, and 7. +◦ Fixed bug in *CONTROL_CHECK_SHELL if PSID.lt.0 (part set ID) is used +◦ Add new option NORBIC to *CONTROL_RIGID to bypass the check of +rigid body inertia tensors being too small. +◦ Add new option ICRQ to *CONTROL_SHELL for continuous treatment of +thickness and plastic strain across element edges for shell element types 2, +4, and 16 with max. 9 integration points through the thickness. +◦ Add new option ICOHED to *CONTROL_SOLID. If this value is set to 1, +solid cohesive elements (ELFORM 19-22) will be eroded when neighboring +(nodewise connected) shell or solid elements fail. +◦ Beam release conditions are now properly supported in selective mass +scaling, see IMSCL on *CONTROL_TIMESTEP. +◦ Modified MSGMAX in *CONTROL_OUPUT: MSGMAX Maximum num- +ber of each error/warning message + > 0 number of message to screen output, all messages written to +messag/d3hsp + < 0 number of messages to screen output and message/d3hsp + = 0 the defaul is 50 +◦ Fix bugs in 3D solid adaptivity (*CONTROL_ADAPTIVE,ADPOPT = 7) so +that the solid adaptivity will still work when there are any of the following +in the model: + thick shells (*SECTION_TSHELL), + massless nodes, +INTRODUCTION + *LOAD_SEGMENT_{option}. +◦ Added PARA = 2 to *CONTROL_PARALLEL which actives consistent +for +force assembly in +SMP. An efficient parallel algorithm is implemented for better perfor- +mance when the consistency flag is turned on. It shows better scaling with +more cpus. This option is overridden by parameter "para=" on the execu- +tion line. +parallel +• DEM(Discrete Element Method) +◦ Added output of following DES history variables to d3plot: + nodal stress and force + pressure + density + force chain + damage calculation when *DEFINE_DE_BOND is defined +◦ Added output of +following DES history variables +to demtrh +(*DATABASE_TRACER_DE): + coordination number + porosity and void ratio + stress + pressure + density +◦ Output ASCII format for demrcf if BINARY.eq.3. +◦ Implement gauss distribution of DE sphere radius for *DEFINE_DE_ +INJECTION. The mean radius is 0.5*(rmin+rmax) and standard deviation +is 0.5*(rmax-rmin). +◦ For DE sphere, implement the stress calculation for REV (Representative +Elementary Volume) using *DATABASE_TRACER_DE and specific RA- +DIUS. +◦ Add *BOUNDARY_DE_NON_REFLECTING for defining non-reflecting +boundary conditions for DE spheres. +◦ For *CONTROL_DISCRETE_ELEMENT, add the option to create the liq- +uid bridge if the initial distance between two DE spheres is smaller than +predefined gap. +◦ Added *DATABASE_DEMASSFLOW, see *DEFINE_DE_MASSFLOW_ +PLANE, for measuring the mass flow of DE spheres through a surface. +The surface is defined by part or part set. Output file is 'demflow'. +◦ Add *DEFINE_DE_INJECTION_ELLIPSE, to define a circular or elliptical +injection plane. +INTRODUCTION +◦ Add *DEFINE_PBLAST_AIRGEO for *PARTICLE_BLAST which defines +initial geometry for air particles. +◦ Add DEM stress calculation when coupling with segment (*DEFINE_DE_ +TO_SURFACE_COUPLING). +◦ Fix error in demtrh file output (Window platform only). +• EFG (Element Free Galerkin) +◦ Fix bug for ELFORM = 41 implicit when there are 6-noded/4-noded ele- +ments. +• *ELEMENT +◦ Fix a 2d seatbelt bug triggered by having both 1d and 2d seatbelts, and a +1d pretensioner of type 2, 3 or 9. +◦ Fix MPP bug initializing multiscale spotweld in the unexpected case where +the spotweld beam is merged with the shells rather than tied via contact. +◦ Fix bug for *INCLUDE_UNITCELL. +◦ *CONTROL_REFINE_...: Implement the parent-children transition in +*CONTACT_2D_SINGLE_SURFACE when a shell refinement occurs. +◦ Fix error traps for *ELEMENT_SEATBELT_... , for example, error termina- +tion due to convergence failure in retractors. These error traps worked but +could lead to a less graceful termination than other LS-DYNA error traps. +◦ Correct calculation of wrap angle in seatbelt retractor. +◦ Add MPP support for *ELEMENT_LANCING. +◦ *ELEMENT_SEATBELT: + Fix a MPP belt bug that can happen when buckle pretensioner is +modeled as a type-9 pretensioner. + 2D belt and 1D belt now can share the same *MAT_SEATBELT. + The section force for 2d belt is recoded to provide more robust and +accurate results. + The loading curve LLCID of *MAT_SEATBELT can be a table defin- +ing strain-rate dependent stiffness curve. + IGRAV of *ELEMENT_SEATBELT_ACCELEROMETER can be a +curve defining gravitation flag as a function of time. +◦ Add *NODE_THICKNESS to override shell nodal thickness otherwise de- +termined via *SECTION_SHELL, *PART_COMPOSITE, or *ELEMENT_ +SHELL_THICKNESS. +◦ Fix input error when using *DEFINE_ELEMENT_DEATH with BOXID > 0 +for MPP. +◦ Implement subcycling for thick shells. +◦ Fix ineffective *DEFINE_HAZ_PROPERTIES when solid spotwelds and +hex spotweld assemblies are both present. +INTRODUCTION +◦ Fix incorrect beta written out for *ELEMENT_SHELL_BETA in dynain file +when *PART_COMPOSITE keyword is present in the original input. +◦ Fix NaN output to elout_det and spurious element deletion if NO- +DOUT = STRAIN or STRAIN_GL or ALL or ALL_GL. +◦ Fix incorrect reading of TIME in card 3 of *ELEMENT_SEATBELT_ +SENSOR SBSTYP = 3 when long = s in command line. +◦ *PART_COMPOSITE: Increased the explicit solution time step for thin +shell composite elements. The existing method was overly conservative. +The new method is based on average layer stiffness and density. +◦ In conjunction with the above change in composite time step calculation, +increase nodal inertia in the rare cases of *PART_COMPOSITE in which +the bending stability is not satisfied by the membrane stability criterion. +The inertia is only increased in the cases where it is necessary; for most +models this change has no effect, but this can occur in the case of sandwich +sections with stiffer skins around a less stiff core. +◦ Corrected rotational inertia of thin shells when layers have mixed density +and the outer layers are more dense than inner layers. The fix will mostly +affect elements that are very thick relative to edge length. +◦ Fixed default hourglass control when the *HOURGLASS control card is +used but no HG type is specified. We were setting to type 1 instead of 2. +Also, fixed the default HG types to match the User's Manual for implicit +and explicit. +◦ Fixed the part mass that was reported to d3hsp when *ELEMENT_SHELL_ +SOURCE_SINK is used. The inactive elements were being included caus- +ing too high mass. +◦ Prevent inactive shell elements (from *ELEMENT_SHELL_SOURCE_ +SINK) from controlling the solution time step. +◦ Fixed the reported strain tensor in elements created by *ELEMENT_ +SHELL_SOURCE_SINK when strain output is requested. The history was +being retained from the previous elements with the same ID. +◦ Fixed torsion in linear beam form 13. A failure to add the torsional mo- +ment at node 2 caused an inability to reach equilibrium in the torsional +mode. +◦ Fixed solid element 4 so that rigid body translation will not cause strain +and stress due to round-off error. +◦ Mixed parallel consistency when used with solid element type 20. A buffer +was not being allocated leading to a memory error. +◦ Changed the MPP behavior of discrete beams (ELFORM = 6) when at- +tached to elements that fail. They were behaving like null beams, in the +sense that it was possible for beam nodes to become dead due to attached +elements failing, and discrete beams would be no longer visualized even if +the beams themselves had not failed. With this change, the MPP discrete +beams now behave like other beams in that the beams have to fail before +they are removed. MPP and SMP behavior is now consistent. +INTRODUCTION +◦ Improved the precision of the type 2 Belytschko Schwer resultant beam to +prevent energy growth in single precision. +◦ Fixed the NLOC option on *SECTION_SHELL for the BCIZ triangle ele- +ments (ELFORM = 3) and the DKT triangle elements (ELFORM = 17). The +offset was scaled by the solution time step so typically the offset was much +smaller than expected. +◦ Fixed elout stress output for shell element forms 23 and 24. The in-plane +averaging was incorrect causing wrong output. +◦ Changed *ELEMENT_TSHELL so that both the COMPOSITE and BETA +options can be read at the same time. Prior to the fix, only the first one +would be read. +◦ Fixed all thick shells to work with anisotropic thermal strains which can be +defined by *MAT_ADD_THERMAL. Also, this now works by layer for +layered composites. +◦ Fixed implicit solutions with thick shells with *MAT_057 when there are +also solid elements in the model that use *MAT_057. Thick shells support +only the incremental update of the F tensor but a flag was set incorrectly in +the material model. +◦ Fixed *MAT_219 when used with thick shell types 3, 5, and 7. A failure to +initialize terms for the time step caused a possible wrong time step. +◦ Fixed orthotropic user defined materials when used with thick shell ele- +ments. The storing of the transformation matrix was in the wrong location +leading to wrong stress and strain. +◦ For thick shell composites that use element forms 5 and 7, the user can now +use laminated shell theory along with the TSHEAR = 1 on *SECTION_ +TSHELL to get a constant shear stress through the thickness with a compo- +site. +◦ Fixed the initialization of *MAT_CODAM2/*MAT_219 when used with +thick shell forms 3, 5, or 7. The 3D thick shell routine uses only 2 terms for +the transformation and therefore needs unique initialization of the trans- +formation data. +◦ Fixed thick shell types 3 and 5 when used in implicit solutions with +*MATs 2, 21, 261, and 263. The material constitutive matrix for *MATs 2 +and 21 was not rotated correctly causing wrong element stiffness. The +constitutive matrix for *MATs 261 and 263 was not orthotropic. Also, for +*MAT_021, type 5 thick shell needed some material terms defined to cor- +rect the assumed strain. +◦ Fixed thick shell forms 3 and 5 when used in implicit solutions with non- +isotropic materials. The stiffness matrix was wrong due to incorrect trans- +formations. +◦ Also, fixed the implicit stiffness of thin and thick shells when used with +laminated shell +(LAMSHT = 3,4,5 on +*CONTROL_ACCURACY). Elements were either failing to converge or +converging more slowly due to the failure to adjust the stiffness matrix to +be consistent with the assumed strain. +theory by assumed strain +INTRODUCTION +◦ Added support for *ELEMENT_SHELL_SOURCE_SINK to form 2 ele- +ments with BWC = 1 on *CONTROL_SHELL. +◦ Fixed the s-axis and t-axis orientation of beam spot welds in the MPP ver- +sion when those beam weld elements are defined with a 3rd node. The 3rd +node was being discarded prior to initializing the beam orientation so the s +and t-axes were being randomly assigned as if the 3rd node had not been +assigned. The effect on solutions is likely fairly minimal since beam mate- +rial is isotropic and failure typically is too, but may not be. +◦ Added Rayleigh damping (*DAMPING_PART_STIFFNESS) for thick shell +formulations 1, 2, and 6. Previously, it was available for only the thick +shells that call 3D stress updates, (forms 3 and 5), but now it is available for +all thick shell formulations. +◦ Added new SCOOR options for discrete beam section 6 (*SECTION_ +BEAM). A flaw was found in how the discrete beam accounts for rigid +body rotation when SCOOR = -3, -2, +2, and +3. A correction for this is +made and introduced as new options, SCOOR = -13, -12, +12, and +13. A +decision was made to leave the existing options SCOOR = -2, +2, -3 and +3 +unchanged so that legacy data could run without changes. +◦ Enabled the ELFORM 18 linear DKT shell element to work with *PART_ +COMPOSITE and with an arbitrary number of through thickness integra- +tion points. It was limited to a single material and 10 Gauss points. +◦ Added the possibility to write *ELEMENT_SOLID_ORTHO into dynain +file if requested. To activate this add OPTCARD to *INTERFACE_ +SPRINGBACK and set SLDO = 1. +◦ Refine characteristic length calculation for 27-node solid (ELFORM 24). +This change may increase the time step substantially for badly distorted el- +ements. +◦ Implement selective reduced integration for 27-node solid (ELFORM 24). +◦ Allow part sets to be used in *DEFORMABLE_TO_RIGID_AUTOMATIC. +Either PID is defined negative or "PSET" is set in column 3 (D2R) or 2 +(R2D). +◦ Add new option STRESS = 2 to *INCLUDE_STAMPED_PART: no stresses +and no history variables are mapped with that setting. +◦ New keyword *PART_STACKED_ELEMENTS provides a method to de- +fine and to discretize layered shell-like structures by an arbitrary sequence +of shell and/or solid elements over the thickness. +◦ The geometric stiffness matrix for the Belytschko beam element type 2 has +been extended to include nonsymmetric terms arising from nonzero mo- +ments. Provides "almost" quadratic convergence, still some terms missing +to be added in the future. Also support a strongly objective version acti- +vated by IACC on *CONTROL_ACCURACY. +◦ The geometric stiffness for the Hughes-Liu element type 1 is fixed. +◦ Fix parsing error in *SECTION_BEAM_AISC. +• EM (Electromagnetic Solver) +INTRODUCTION +◦ Add the new EM 2d axi solver in SMP and MPP for EM solver 1 (eddy cur- +rent). It is coupled with the mechanics and thermal solvers. +◦ The new EM 2d can be used with RLC circuits on helix/spiral geometries +using *EM_CIRCUIT_CONNECT. +◦ Add EM contact into new EM 2d axi, in SMP and MPP. +◦ Add *EM_BOUNDARY support in new EM 2d axi solver. +◦ Introduce scalar potential in new EM 2d axi. The 2d axi can also be cou- +pled with imposed voltage. +◦ Add new keyword *EM_CIRCUIT_CONNECT to impose linear constraints +between circuits with imposed currents in 3d solvers. This allows for ex- +ample to impose that the current in circuit 1 is equal to the current in cir- +cuit 2 even if the 2 corresponding parts are not physically connected. +◦ Add *EM_VOLTAGE_DROP keyword to define a voltage drop between 2 +segment sets. This voltage drop constraint is coupled to the contact con- +straint so that the contact (voltage drop = 0) has priority over the *EM_ +VOLTAGE_DROP constraint. +◦ Add *EM_CONTROL_SWITCH_CONTACT keyword to turn the EM con- +tact detection on and off. +◦ NCYCLBEM/NCYCLFEM in *EM_SOLVER_... can now be different than +1 when EM_CONTACT detected. +◦ Add RLC circuit for type 3 solver (resistive heating). +◦ Add computation of mutuals/inductances in 2d axi for output to em_ +circuit.dat +◦ Add criteria on autotimestep calculation when R,L,C circuit used to take +into account R,L,C period. +◦ Fix keyword counter in d3hsp. +◦ Better and clearer output to terminal screen. +◦ Support jobid for EM ascii file outputs. +• Forming +◦ Improvements to trimming: + *DEFINE_CURVE_TRIM_NEW: if trim seed node is not defined, we +will search a seed node based on nodes from the sheet blank and the +inside/outside flag definition for the trimming curves. + Map strain tensors to triangular elements after trimming. +◦ Add a new function to the trim of solid elements in normal (3-D) trimming +case, related to *DEFINE_CURVE_TRIM_3D. If the trimming curve is +close to the bottom side, set TDIR = -1. If the trimming curve is close to the +upper side, set TDIR = 1. +INTRODUCTION +◦ Add to *ELEMENT_LANCING. Allow parametric expression for variables +END and NTIMES. +◦ A bug fix for *CONTROL_FORMING_AUTOPOSITION_PARAMETER_ +SET: Fix distance calculation error when the target mesh is too coarse. +◦ Improvements to springback compensations: + Output the new trimming curve with *DEFINE_CURVE_TRIM_3D +(previously *DEFINE_CURVE_TRIM), so that it can be easily con- +verted to IGES curve by LS-PrePost. or used in another trimming cal- +culation. + Output each curve to IGES format in the following name format: +newcurve_scp001.igs, newcurve_scp002.igs, newcurve_scp003.igs, +etc. + Output change in file "geocur.trm". This update will allow change +from *DEFINE_CURVE_TRIM(_3D,_NEW), whatever is used for in- +put. +◦ Add a new keyword: *DEFINE_FORMING_CONTACT to facilitate the +forming contact definitions. +◦ Add a new keyword *DEFINE_FORMING_CLAMP, to facilitate clamping +simulation. +◦ A new feature in mesh fusion, which allows a moving box to control the +fusion, only if the center of the elements is inside the box can the elements +can be coarsened. Can be used in conjuntion with *DEFINE_BOX_ +ADAPTIVE. +◦ Add a new feature to *DEFINE_BOX_ADAPTIVE: Moving box in adaptiv- +ity, useful in roller hemming and incremental forming. +◦ In mesh coarsening, if the node is defined in a node set, the connected ele- +ments will be kept from being coarsened. Previously, only *SET_NODE_ +LIST was supported. Now option *SET_NODE_GENERAL is allowed. +◦ Add a new function: mesh refinement for sandwich part. The top and bot- +tom layers are shell elements and the middle layer is solid elements. Set +IFSAND to 1 in *CONTROL_ADAPTIVE. + Applies to both 8-noded and 6-noded solid elements. + Map stress and history variables to the new elements. +◦ New +features related +BLANKSIZE_DEVELOPMENT: +to blank size development *INTERFACE_ + Add *INTERFACE_BLANKSIZE_SYMMETRIC_PLANE to define +symmetric plane in blank size development + Add *INTERFACE_BLANKSIZE_SCALE_FACTOR. For each trim- +ming, different scale factors can be used to compensate the blanksize. +This is especially useful when the inner holes are small. Includes an +INTRODUCTION +option of offset the target curve which is useful if multiple target +curves (e.g., holes) and formed curves are far from each other. + Allow target curve to be outside of the surface of the blank. + Add sorting to the mesh so the initial mesh and the formed mesh do +not need to have the same sequence for the nodes. + Add a new variable ORIENT, set to "1" to activate the new algorithm +to potentially reduce the number of iterations with the use of +*INTERFACE_BLANKSIZE_SCALE_FACTOR (scale = 0.75 to 0.9). + Fix smooth problem along calculated outer boundary. + Automatically determine the curve running directions (IOPTION = 2 +and -2 now both give the same results). + Accept parameteric expression. +◦ A bug fix for springback compensation: *INCLUDE_COMPENSATION_ +SYMMETRIC_LINES Fix reading problem of free format in the original +coding. +◦ Add a new keyword *CONTROL_FORMING_BESTFIT. Purpose: This +keyword rigidly moves two parts so that they maximally coincide. This +feature can be used in sheet metal forming to translate and rotate a spring +back part (source) to a scanned part (target) to assess spring back predic- +tion accuracy. This keyword applies to shell elements only. +◦ Improvements to *CONTROL_FORMING_AUTOCHECK: + When IOFFSET = 1, rigid body thickness is automatically offset, +based on the MST value defined in *CONTACT_FORMING_ONE_ +WAY_SURFACE. + Add new variable IOUTPUT that when set to 1 will output the offset +rigid tool mesh, and the new output tool file is: rigid_offset.inc. After +output the simulation stops. See R9.0 Manual for further details. + When both normal check and offset are used, small radius might +cause problem for offsetting. The new modification will check the +normal again after offsetting the tool + When outputting the rigid body mesh, output the bead nodes also. + Changes to *CONTROL_FORMING_AUTOCHECK when used to- +gether with SMOOTH option: check and fix rigid body bad elements +before converting the master part ID to segment set id to be used by +SMOOTH option. + Set IOUTPUT.eq. 3 to output rigid body mesh before and after offset. + Fix problems offseting a small radius to a even smaller radius. + Remove T-intersection. +◦ For *CONTROL_IMPLICIT_FORMING, fix output messages in d3hsp that +incorrectly identified steps as implicit dynamic when they were actually +implicit static. +◦ Improve *CONTROL_FORMING_UNFLANGING: +INTRODUCTION + Automatically calculate CHARLEN, so user does not need to input it +anymore. + Allow nonsmooth flange edge. + Instead of using preset value of 0.4 (which works fine for thin sheet +metal), blank thickness is now used to offset the slave node (flanges) +from the rigid body (die). +• *FREQUENCY_DOMAIN +◦ *FREQUENCY_DOMAIN_RANDOM_VIBRATION: Fixed a bug in dump- +ing d3psd binary database, when both stress and strain are included. +◦ *FREQUENCY_DOMAIN_SSD_ERP: Implemented the Equivalent adiated +Power (ERP) computation to MPP. +◦ *FREQUENCY_DOMAIN_ACOUSTIC_BEM: + Enabled running dual collocation BEM based on Burton-Miller for- +mulation (METHOD = 4) with vibration boundary conditions pro- +vided by Steady State Dynamic analysis (*FREQUENCY_DOMAIN_ +SSD). + Added exponential window function for FFT (FFTWIN = 5). + Implemented a new forward and backward mixed radix FFT. + Implemented acoustic computation restart from frequency domain +boundary conditions, in addition to time domain boundary condi- +tions (RESTRT = 1). + Enabled out-of-core velocity data storage, to solve large scale prob- +lems. + Implemented option HALF_SPACE to Rayleigh method (METH- +OD = 0) to consider acoustic wave reflection. + Added velocity interpolation to take care of mismatching between +acoustic mesh and structural mesh (*BOUNDARY_ACOUSTIC_ +MAPPING), for the case that the boundary conditions are provided +by Steady State Dynamic analysis. + Added weighted SPL output to acoustic computation (DBA = 1,2,3,4). + Implemented radiated sound power, and radiation efficiency compu- +tation to collocation BEMs (METHOD = 3,4). Added new ASCII xy- +plot databases Press_Power and Press_radef to save the sound power +and radiation efficiency results. + Enabled using both impedance and vibration (velocity) boundary +conditions in acoustic simulation. +◦ *FREQUENCY_DOMAIN_ACOUSTIC_FEM: + Added weighted SPL output to FEM acoustics (DBA = 1,2,3,4). + Implemented option EIGENVALUE to perform acoustic eigenvalue +analysis; added ASCII database eigout_ac to save acoustic eigenvalue +INTRODUCTION +results; added binary plot database d3eigv_ac to save acoustic eigen- +vectors. + Enabled consideration of nodal constraints in acoustic eigenvalue +analysis. + Enabled FEM acoustic analysis with frequency dependent complex +sound speed. + Implemented pressure and impedance boundary conditions. +◦ *FREQUENCY_DOMAIN_ACOUSTIC_FRINGE_PLOT: + Added this keyword to 1) generate acoustic field points as a sphere or +plate mesh (options SPHERE and PLATE), or 2) define acoustic field +points mesh based on existing structure components (options PART, +PART_SET and NODE_SET) so that user can get fringe plot of acous- +tic pressure and SPL. The results are saved in binary plot database +d3acs (activated by keyword *DATABASE_FREQUENCY_BINARY_ +D3ACS). +◦ *FREQUENCY_DOMAIN_RANDOM_VIBRATION: + Changed displacement rms output in d3rms to be the displacement +itself, without adding the original nodal coordinates. + Implemented von mises stress PSD computation in beam elements. + Implemented fatigue analysis with beam elements. + Added strain output to binary plot databases d3psd and d3rms, and +binout database elout_psd. + Added initial damage ratio from multiple loading cases (INFTG > 1). +◦ *FREQUENCY_DOMAIN_SSD: + Implemented option ERP to compute Equivalent Radiated Power. It +is a fast and simplified way to characterize acoustic behavior of vi- +brating structures. The results are saved in binary plot database +d3erp (activated by keyword *DATABASE_FREQUENCY_BINARY_ +D3ERP), and ASCII xyplot files ERP_abs and ERP_dB. + Implemented fatigue analysis based on maximum principal stress +and maximum shear stress. +• ICFD (Incompressible Flow Solver) +◦ *ICFD_BOUNDARY_FSWAVE: Added a boundary condition for wave +generation of 1st order stokes waves with free surfaces. +◦ *ICFD_DATABASE_DRAG_VOL: For computing pressure forces on vol- +umes ID (useful for forces in porous domains), output in icfdragivol.dat +and icfdragivol.#VID.dat. +INTRODUCTION +◦ *ICFD_CONTROL_DEM_COUPLING: Coupling the ICFD solver with +DEM particles is now possible. +◦ *ICFD_CONTROL_MONOLITHIC: Added a monolithic solver (=1) which +can be selected instead of the traditional fractional step solver (=0). +◦ *ICFD_CONTROL_POROUS: This keyword allows the user to choose be- +tween the Anisotropic Generalized Navier-Stokes model (=0) or the Aniso- +tropic Darcy-Forchheimer model (=1) (for Low Reynolds number flows). +The Monolithic solver is used by default for those creeping flows. +◦ *ICFD_CONTROL_TURBULENCE: + Modified existing standard k-epsilon. + Added Realizable k-epsilon turbulence model. + Added Standard 98 and 06 Wilcox and Menter SST 03 turbulence +models. + Added Several laws of the wall. + Added Rugosity law when RANS turbulence model selected. +◦ *ICFD_MODEL_POROUS: + Added Porous model 5 for anistropic materials defined by P-V exper- +imental curves. + Added porous model 6 for moving domain capabilities for Porous +Media volumes using load curves for permeabilities directions. + Added porous model 7 for moving domain capabilities for Porous +Media volumes using ICFD_DEFINE_POINT for permeabilities di- +rections. + Added porous model 9 for a new Anisotropic Porous Media flow +model (PM model ID = 9): It uses a variable permeability tensor field +which is the result of solid dynamic problems. The model reads the +solid mesh and the field state and maps elemental permeability ten- +sor and solid displacements to the fluid mesh. +◦ *ICFD_MODEL_NONNEWT: + Added a few models for non newtonian materials and temperature +dependant viscosity : +• model 1 : power law non newtonian (now also temperature +dependant) +• model 2 : carreau fluid +• model 3 : cross fluid +• model 4 : herschel-bulkley +• model 5 : cross fluid II +• model 6 : temperature dependant visc (sutherland) +• model 7 : temperature dependant visc (power law) +INTRODUCTION +• model 8 : load curve dependant visc, model 8 is especially +interesting since a DEFINE_FUNCTION can be used (for so- +lidification applications). +◦ *ICFD_SOLVER_TOL_MONOLITHIC: Used to define atol, rtol, dtol and +maxits linear solver convergence controls of the monolithic NS time inte- +gration +◦ *MESH_BL: Added support for boundary layer mesh creation by specify- +ing the thickness, number of layers, first node near the surface and the +strategy to use to divide and separate the elements inside the BL adding. +◦ *ICFD_BOUNDARY_PRESCRIBED_VEL: Added the support of DEFINE_ +FUNCTION making the second line of the keyword obsolete. +◦ *ICFD_CONTROL_TIME: Min and Max timestep values can be set. +◦ *ICFD_DATABASE_DRAG: + Added frequency output. + Added option to output drag repartition percentage in the d3plots as +a surface variable. +◦ *ICFD_CONTROL_IMPOSED_MOVE: This keyword now uses *ICFD_ +PART and *ICFD_PART_VOL instead of *MESH_VOL for ID. It is now +possible to impose a rotation on a part using Euler angles. +◦ *ICFD_CONTROL_OUTPUT: + Field 4 now to output mesh in LSPP format and in format to be run +by the icfd solver (icfd_fluidmesh.key and icfd_mesh.key) + icfd_mesh.key now divides the mesh in ten parts, from best quality +element decile to worst. + A new mesh is now output at every remeshing. + Added support for parallel I/O for Paraview using the PVTU format. +◦ *ICFD_DEFINE_POINT: Points can now be made to rotate or translate. +◦ *ICFD_MAT: + Nonnewtonian models and Porous media models are now selected in +the third line by using the new ICFD_MODEL keyword family. + HC and TC can now be made temperature dependent. +◦ *ICFD_CONTROL_DIVCLEAN: Added option 2 to use a potential flow +solver to initialize the Navier Stokes solver. +◦ *ICFD_CONTROL_FSI: Field 5 provides a relaxation that starts after the +birthtime. +◦ *ICFD_CONTROL_MESH: Field 3 added a new strategy to interpolate a +mesh size during the node insertion. In some cases it speeds up the mesh- +ing process and produces less elements. Field 4 changes the meshing +strategy in 2d. +INTRODUCTION +◦ *ICFD_CONTROL_SURFMESH: Added +meshing/adaptation of surface meshing. +support +for dynamic +re- +◦ *ICFD_BOUNDARY_PRESCRIBED_VEL:VAD = 3 now works with +DOF = 4. +◦ SF can be lower than 0. +◦ PID can be over 9999 in *ICFD_DATABASE_FLUX. +◦ Fixed d3hsp keyword counter. +◦ Clarified terminal output. +◦ Y+ and Shear now always output on walls rather than when a turbulence +model was selected. +◦ Added coordinate of distorted element before remeshing occurs. Output +on terminal and messag file +◦ Fixed bug in conjugate heat transfer cases. When an autotimestep was se- +lected in *ICFD_CONTROL_TIME, it would always only take the thermal +timestep. +◦ An estimation of the CFL number is now output in the d3plot files. This is +not the value used for the autotimestep calculation. +◦ Turbulence intensity is now output in the d3plots. +◦ Jobid now supported for ICFD ASCII File outputs. +◦ Fixed communication of turbulent constants in MPP. +◦ Fixed the Near Velocity field output. +◦ Increasing the limit of number of parts for the model. +◦ Temperature added as a surface variable in output. +◦ Fixed non-linear conjugate heat solver. +• Implicit +◦ Fixed Implicit for the case of Multi-step Linear (*CONTROL_IMPLICIT_ +GENERAL with NSOLVR = 1) with Intermittent Eigenvalue Computation +(*CONTROL_IMPLICIT_EIGENVALUE with NEIG < 0). +◦ Recent fix for resultant forces for Multi-step Linear cause segmentation +fault when Intermittent Eigenvalue Computation was also active. +◦ Fix possible issue related to constrained contacts in MPP implicit not ini- +tializing properly. +◦ Fixed label at beginning of implicit step to be correct for the case of control- +load curve (*CONTROL_IMPLICIT_ +implicit dynamics via a +ling +DYNAMICS). +◦ Corrected the computation of modal stresses with local coordinate terms +and forsome shell elements . +◦ Corrected *CONTROL_IMPLICIT_INERTIA_RELIEF logic in MPP. In +some cases the rigid body modes were lost. +◦ Enhanced implicit's treatment of failing spotwelds (*CONSTRAINED_ +SPOTWELD). +INTRODUCTION +◦ Added additional error checking of input data for *CONTROL_IMPLICIT_ +MODAL_DYNAMICS_DAMPING. +◦ Per user request we added the coupling of prescribed motion constraints +for Modal Dynamics by using constraint modes. See *CONTROL_ +IMPLICIT_MODAL_DYNAMIC. +◦ Added reuse of the matrix reordering for MPP implicit execution. This +will reduce the symbolic processing time which is noticable when using +large numbers of MPP processes. Also added prediction of non tied con- +tact connections for standard contact and mortar contact. This allows re- +use of the ordering when contact interfaces are changing very slightly but +can increase the cost of the numerical factorization. Useful only for MPP +using large numbers of processes for large finite element models. This re- +use checking happens automatically for MPP and is not required for SMP. +◦ Apply improvements to Metis memory requirements used in Implicit +MPP. +◦ Enhanced Metis ordering software +(ORDER = 2, +the default, on +*CONTROL_IMPLICIT_SOLVER). +◦ Added new keyword *CONTROL_IMPLICIT_ORDERING to control of +features of the ordering methods for the linear algebra solver in MPP Im- +plicit. Only should be used by expert users. +◦ The following 4 enhancements are applicable when IMFLAG > 1 on +*CONTROL_IMPLICIT_GENERAL. + Implicit was modified to reset the time step used in contact when +switching from implicit to explicit. + Adjusted implicit mechanical time step for the case of switching from +explicit to implicit so as not to go past the end time. + Explicit with intermittent eigenvalue analysis was getting incorrect +results after the eigenvalue analysis because an incorrect time step +was used for the implicit computations. For this scenario implicit +now uses the explicit time step. + The implicit time step is now reset for the dump file in addition to +explicit's time. +◦ Implicit's treatment of prescribed motion constraints defined by a box had +to be enhanced to properly handle potential switching to explicit. +◦ The following 6 enhancements are for matrix dumping (MTXDMP > 0 on +response +frequency +for +*CONTROL_IMPLICIT_SOLVER) +(*FREQUENCY_DOMAIN) computations. +or +◦ Corrected the collection of *DAMPING_PART_STIFFNESS terms for ele- +ments like triangles and 5, 6, and 7 node solid elements. +◦ Corrected Implicit's access of *DAMPING_PART_STIFFNES parameter +when triangle and tet sorting is activated. +◦ Fixed Implicit's collecting of damping terms for beams that have reference +nodes. +INTRODUCTION +◦ There is an internal switch that turns off damping for beams if the run is +implicit static. This switch needed to be turned off for explicit with inter- +mittent eigenvalue analysis. +◦ Fixed collecting of stiffness damping terms for implicit. Corrected the +loading of mass damping terms when collecting damping terms for post +processing. +◦ Extend matrix dumping to include dumping the solution vector in addi- +tion to the matrix and right-hand-side. +◦ Adjusted Implicit's handling of sw1. and sw3. sense switches to properly +handle dumping. If sw1. sense switch is issued when not at equilibrium, +then reset time and geometry to that at the end of last implicit time step. If +sw3. sense switch is issued, then wait until equilibrium is reached before +dumping and continuing. +◦ Enable the use of intermittent eigenvalue computation for models using +inertia relief and/or rotational dynamics. See NEIG < 0 on *CONTROL_ +IMPLICIT_EIGENVALUE +and +*CONTROL_IMPLICIT_ROTATIONAL_DYNAMICS. Due to round-off, +an implicit intermittent eigenvalue computation was occasionally skipped. +A fudge factor of 1/1000 of the implicit time step was added to compen- +sate for round-off error in the summation of the implicit time. See +NEIG < 0 on *CONTROL_IMPLICIT_EIGENVALUE. +*CONTROL_INERTIA_RELIEF +and +◦ Added support for *CONSTRAINED_LINEAR for 2D implicit problems. +It was already supported for standard 3D problems. +◦ Added warning for implicit when the product of ILIMIT and MAXREF +(two parameters on *CONTROL_IMPLICIT_SOLUTION) is too small. For +the special case when the user changes the default of ILIMIT to 1 to choose +Full Newton and does not change MAXREF then MAXREF is reset to 165 +and a warning is generated. Reinstate the option of MAXREF < 0. +◦ Fixed the display of superelements in LS-PrePost. Enhanced reading of +Nastran dmig files to allow for LS-DYNA-like comment lines starting with +'$'. Fixed a problem with implicit initialization in MPP with 2 or more su- +perelements. See *ELEMENT_DIRECT_MATRIX_INPUT. +◦ Turned off annoying warning messages associated with zero contact ele- +mental stiffness matrices coming from mortar contact. See *CONTACT_..._ +MORTAR +◦ Fixed construction of d3mode file in MPP. Involves proper computation of +the reduced stiffness matrix. See *CONTROL_IMPLICIT_MODES +◦ Fixed up *PART_MODES to correctly handle constraint modes. + removed rigid body modes + correct construction of reduced stiffness matrix +◦ Enhanced the error handling for input for *PART_MODES. +◦ Modified open statements for binary files used by implicit to allow for use +of *CASE. +INTRODUCTION +◦ Removed internal use files such as spooles.res when not required for de- +bugging. +◦ Fixed implicit static condensation and implicit mode computation to +properly deal with the *CASE environment. See *CONTROL_IMPLICIT_ +STATIC_CONDENSATION and *CONTROL_IMPLICIT_MODES. Sort +node/dof sets for implicit_mode to get correct results. Properly handle +cases with only solid elements. +◦ Add implicit implementation of the new "last location" feature for MPP er- +ror tracking. +◦ Fixed problem with implicit processing of rigid body data with deformable +to rigid switching (*DEFORMABLE_TO_RIGID). +◦ Extended Implicit model debugging for LPRINT = 3 (*CONTROL_ +IMPLICIT_SOLVER) to isogeometric and other large elemental stiff matri- +ces. +◦ Added beam rotary mass scaling to the modal effective mass computation. +Enhanced implicit computation of modal effective mass that is output to +file eigout with *CONTROL_IMPLICIT_EIGENVALUE. We had to ac- +count for boundary SPC constraints as well as beam reference nodes to get +the accumulated percentage to add up to 100%. +◦ Fixed a problem reporting redundant constraints for MPP Implicit. +◦ Enhanced *CONTACT_AUTO_MOVE for implicit. +◦ Fixed Implicit handling of *CONSTRAINED_TIE-BREAK in MPP. +◦ Added support for implicit dynamics to *MAT_157 and *MAT_120. +◦ Skip frequency damping during implicit static dynamic relaxation. +◦ Added feature to simulate brake squeal. Transient and mode analysis can +be combined to do the brake squeal study by intermittent eigenvalue anal- +ysis. +*CONTROL_IMPLICIT_ROTATIONAL_DYNAMICS, +*CONTROL_IMPLICIT_SOLVER should also be used, setting LCPACK = 3 +to enable unsymmetric stiffness matrix. In the non-symmetric stiffness ma- +trix analysis such as brake squeal analysis, the damping ratio, defined as - +2.0*RE(eigenvalue)/ABS(IMG(eigenvalue)), can be output to the eigout file +and plotted in LS-PrePost. A negative damping ratio indicates an unstable +mode. + Besides +◦ Add a warning message if the defined rotational speed is not the same as +NOMEG in *CONTROL_IMPLICIT_ROTATIONAL_DYNAMICS. +◦ *CONTROL_IMPLICIT: Fixed a bug to initialize velocity correctly when +using a displacement file in dynamic relaxation for implicit MPP. +◦ Nonlinear implicit solver 12 is made default implicit solver, which is aimed +for enhanced robustness in particular relation to BFGS and line search. +◦ Parameter IACC available on *CONTROL_ACCURACY to invoke en- +hanced accuracy in selected elements, materials and tied contacts. Includ- +ed is strong objectivity in the most common elements, strong objecitity and +physical respons in most commont tied contacts and full iteration plasticity +in *MATs 24 and 123. For more detailed information refer to the manual. +INTRODUCTION +◦ Bathe composite time integration scheme implemented for increased stabil- +ity and conservation of energy/momentum, see *CONTROL_IMPLICIT_ +DYNAMICS. + Time integration parameter ALPHA on CONTROL_ +IMPLICIT_DYNAMICS is used for activation. +◦ For NLNORM.LT.0 all scalar products in implicit are with respect to all +degrees of freedom, sum of translational and rotational (similar to +NLNORM.EQ.4), +the rotational dofs are scaled using +ABS(NLNORM) as a characteristic length to appropriately deal with con- +sistency of units. +that +just +◦ The message 'convergence prevented due to unfulfilled bc...' has annoyed +users. Here this is loosened up a little and also accompanied with a check +that the bc that prevents convergence is actually nonzero. Earlier this pre- +vention has activated even for SPCs modelled as prescribed zero motion, +which does not make sense. +◦ Implicit now writes out the last converged state to the d3plot database on +error termination if not already written. +◦ Fixed bug for *CONTROL_IMPLICIT_MODAL_DYNAMIC if jobid is +used. +• *INITIAL +◦ Fix incorrect NPLANE and NTHICK for *INITIAL_STRESS_SHELL when +output to dynain file for shell type 9. +◦ Fix *INITIAL_STRAIN_SHELL output to dynain for shell types 12 to 15 in +2D analysis. +◦ Write out strain at only 1 intg point if INTSTRN = 0 in *INTERFACE_ +SPRINGBACK_LSDYNA and all strains at all 4 intg points if INTSTRN = 1 +and nip = 4 in *SECTION_SHELL. +◦ *INITIAL_EOS_ALE: Allow initialization of internal energy density, rela- +tive volume, or pressure in ALE elements by part, part set, or element set. +◦ *INITIAL_VOLUME_FRACTION_GEOMETRY: Add option (FAMMG < 0) +to form pairs of groups in *SET_MULTI-MATERIAL_GROUP_LIST to re- +place the first group of the pair by the second one. +◦ *INITIAL_STRESS_DEPTH can now work with parts that have an Equa- +tion of State (EOS types 1, 4, 6 only). Note however that *INITIAL_ +STRESS_DEPTH does not work with ALE. +◦ Fix several instances of overwriting the initial velocities of any interface +nodes read in from a linking file (SMP only). +◦ *INITIAL_VOLUME_FRACTION_GEOMETRY: Add local coordinate sys- +tem option for box. +◦ The +initial strain and energy +is calculated for *INITIAL_FOAM_ +REFERENCE_GEOMETRY. +◦ Add the option of defining the direction cosine using two nodes for +*INITIAL_VELOCITY_GENERATION. +INTRODUCTION +◦ Fix incorrect transformation of *DEFINE_BOX which results in incorrect +initial velocities if the box is used in *INITIAL_VELOCITY. +◦ Fix incorrect initial velocity when using *INITIAL_VELOCITY with NX = - +999. +◦ Fix seg fault when using *INITIAL_INTERNAL_DOF_SOLID_TYPE4 in +dynain file. +◦ Do not transform the translational velocities in *INITIAL_VELOCITY or +*INITIAL_VELOCITY_GENERATION if the local coordinate system ICID +is defined. +◦ Fix uninitialized +*INITIAL_VELOCITY_ +GENERATION with STYP = 2, i.e. part id, for *ELEMENT_SHELL_ +COMPOSITE/*ELEMENT_TSHELL_COMPOSITE. +velocities when using +◦ Fix incorrect initialization of velocities if using *INITIAL_VELOCITY_ +GENERATION with STYP = 1, i.e. part set for shells with formulation 23 +& 24. +◦ Fix incorrect initial velocity and also mass output to d3hsp for shell types +23 & 24. +◦ Fix +incorrect +initial velocities when using *INITIAL_VELOCITY_ +GENERATION with irigid = 1 and *PART_INERTIA with xc = yc = zc = 0 +and nodeid > 0 with *DEFINE_TRANSFORMATION. +◦ Fix incorrect stress initialization of *MAT_057/MAT_LOW_DENSITY_ +FOAM using dynain file with *INITIAL_STRESS_SOLID when NHISV is +equal to the number of history variables for this mat 57. +◦ Fix seg fault when reading dynain.bin +◦ Fixed stress initialization (*INITIAL_STRESS_SECTION) for type 13 tetra- +hedral elements. The pressure smoothing was causing incorrect pressure +values in the elements adjacent to the prescribed elements. +◦ Assign initial velocities (*INITIAL_VELOCITY) to beam nodes that are +generated when release conditions are defined (RT1, RT2, RR1, RR2 on +*ELEMENT_BEAM.) +◦ Added an option to retain bending stiffness in spot weld beams that have +prescribed axial force. To use is, set KBEND = 1 on *INITIAL_AXIAL_ +FORCE_BEAM. +◦ Fix for *INITIAL_STRESS_BEAM when used with spotweld beam type 9. +It was possible that error/warning message INI+140 popped up even if +number of integration points matched exactly. +◦ Fix for the combination of type 13 tet elements and *INITIAL_STRESS_ +SOLID. The necessary nodal values for averaging (element volume, Jaco- +bian) were not correctly initialized. Now the initial volume (IVEFLG) is +used to compute the correct initial nodal volume. +• Isogeometric Elements +◦ Enable spc boundary condition to be applied to extra nodes of nurbs shell, +see *CONSTRAINED_NODES_TO_NURBS_SHELL +INTRODUCTION +◦ Fix a bug for isogeometric element contact, IGACTC = 1, that happens +when more than one NURBS patches are used to model a part so that a in- +terpolated elements have nodes belonging to different NURB patches. +◦ *ELEMENT_SOLID_NURBS_PATCH: + Enable isogeometric analysis for solid elements, it is now able to do +explicit and implicit analysis, such as contact and eigenvalue analysis, +etc. + Add mode stress analysis for isogeometric solid and shell elements so +that the isogeometric element is also able to do frequency domain +analysis. +◦ Add reduced, patch-wise integration rule for C1-continuous quadratic +NURBS. This can be used by setting INT = 2 in *ELEMENT_SHELL_ +NURBS_PATCH. +◦ Add trimmed NURBS capability. Define NL trimming loops to specify a +trimmed NURBS patch. Use *DEFINE_CURVE (DATTYP = 6) to specify +define trimming edges in the parametric space. +◦ Fix bug in added mass report for *ELEMENT_SHELL_NURBS_PATCH in +MPP. +• *LOAD +◦ *LOAD_GRAVITY_PART and staged construction (*DEFINE_STAGED_ +CONSTRUCTION_PART) were ignoring non-structural mass MAREA +(shells) and NSM (beams). Now fixed. +◦ Fix for *INTERFACE_LINKING in MPP when used with adaptivity. +◦ Updates for *INTERFACE_LINKING so that it can be used with adaptiv- +ity, provided the linked parts are adapting. +◦ Fix for *INTERFACE_LINKING when used with LSDA based files gener- +ated by older versions of the code. +◦ *DEFINE_CURVE_FUNCTION: + Functions "DELAY", PIDCTL" and "IF" of are revised. + Add sampling rate and saturation limit to PIDCTL of *DEFINE_ +CURVE_FUNCTION. + "DELAY" of *DEFINE_CURVE_FUNCTION can delay the value of a +time-dependent curve by "-TDLY" time steps when TDLY < 0. +◦ Add edge loading option to *LOAD_SEGMENT_SET_NONUNIFORM. +◦ Fix insufficient memory error,SOL+659, when using *LOAD_ERODING_ +PART_SET with mpp. +◦ Fix incorrect loading when using *LOAD_ERODING_PART_SET with +BOXID defined. +INTRODUCTION +◦ Fix incorrect pressure applied if the directional cosines, V1/V2/V3, for +*LOAD_SEGMENT_SET_NONUNIFORM do not correspond to a unit vec- +tor. +◦ Add *DEFINE_FUNCTION capability to *LOAD_SEGMENT_SET for 2D +analysis. +◦ Fix incorrect behavior when using arrival time, AT, or box, BOXID, in +*LOAD_ERODING_PART_SET. +◦ Fix error when runing analysis with *LOAD_THERMAL_CONSTANT_ +ELEMENT_(OPTION) in MPP with ncpu > 1. +◦ Fixed *LOAD_STEADY_STATE_ROLLING when used with shell form 2 +when used with Belytschko-Wong-Chang warping stiffness (BWC = 1 +*CONTROL_SHELL). +◦ Add "TIMESTEP" as a code defined value available for *DEFINE_ +FUNCTION and *DEFINE_CURVE_FUNCTION. It holds the current +simulation timestep. +◦ Fixed issues involving *LOAD_THERMAL_D3PLOT. +◦ Allow extraction of node numbers in loadsetud for all values of LTYPE in +*USER_LOADING_SET. Comments included appropriately in the code. +Argument list of loadsetud is changed accordingly. +◦ Implemented SPF simulation (*LOAD_SUPERPLASTIC_FORMING) for 2d +problems. +◦ Added effective stress as target variable for SPF simulation. +◦ Added box option for SPF simulation to limit target search regions. +• *MAT +◦ Fix output to d3hsp for *MAT_HYPERELASTIC_RUBBER. Broken in +r93028. +◦ Error terminate with message, KEY+1115, if_STOCHASTIC option is in- +voked for *MATs 10,15,24,81,98, 123 but no *DEFINE_STOCHASTIC_ +VARIATION or *DEFINE_HAZ_PROPERTIES keyword is present in the +input file. +◦ Fix spurious error termination when using *DEFINE_HAZ_PROPERTIES +with adaptivity. +◦ Fixed *MATs 161 and 162 when run with MPP. The array that is used to +share delamination data across processors had errors. +◦ *MAT_261/*MAT_262: Fixed problem using +*DAMPING_PART_ +STIFFNESS together with RYLEN = 2 in *CONTROL_ENERGY. +◦ Added safety check for martensite phase kinetics in *MAT_244. +◦ Fix for combination of *MAT_024_STOCHASTIC and shell elementstype +13, 14, and 15 (with 3d stress state). +◦ Fix bug in *MATs 21 and 23 when used with *MAT_ADD_THERMAL_ +EXPANSION. +◦ *MAT_ALE_VISCOUS: Implement a user defined routine in dyn21.F to +compute the dynamic viscosity. +INTRODUCTION +◦ Add histlist.txt to usermat package. This file lists the history variables by +material. +◦ Bug in *MAT_089 fixed: The load curve LCSS specifies the relationship be- +tween "maximum equivalent strain" and the von Mises stress. The "maxi- +mum equivalent strain" includes both elastic and plastic components. The +material model was not calculating this variable as intended, so was not +following LCSS accurately. The error was likely to be more noticeable +when elastic strains are a significant proportion of the total strain e.g. for +small strains or low initial Youngs modulus. +◦ Fixed bug affecting *MAT_119: unpredictable unloading behaviour in local +T-direction if there are curves only for the T-direction and not for the S- +direction. +◦ Fixed bug in *MAT_172: Occured when ELFORM = 1 (Hughes-Liu shell +formulation) was combined with Invariant Numbering (INN > 0 on +*CONTROL_ACCURACY). In this case, the strain-softening in tension did +not work: after cracking, the tensile strength remained constant. +◦ New option for *MAT_079: Load curve LCD defining hysteresis damping +versus maximum strain to date. This overrides the default Masing behav- +iour. +◦ *MAT_172: + Added error termination if user inputs an illegal value for TYPEC. +Previously, this condition could lead to abnormal terminations that +were difficult to diagnose. + Fixed bug affecting ELFORM = 16 shells made of *MAT_172 – spuri- +ous strains could develop transverse to the crack opening direction. +◦ Fixed bug in *MAT_ARUP_ADHESIVE (*MAT_169). The displacement to +failure in tension was not as implied by the inputs TENMAX and GCTEN. +For typical structural adhesives with elastic stiffness of the order of 1000- +10000 MPa, the error was very small. The error became large for lower +stiffness materials. +◦ *MAT_SPR_JLR: + Modify output variables from *MAT_SPR_JLR . + Fix bug that caused spurious results or unexpected element deletion +if TELAS = 1. +◦ Fixed bug in *MAT_174 - the code could crash when input parameters +EUR = 0 and FRACR = 0.. +◦ Fix MPP problem when writing out aea_crack file for *MAT_WINFRITH. +◦ Include *MAT_196 as one that triggers spot weld thinning. +◦ *MAT_ADD_FATIGUE: Implemented multi slope SN curves to be used in +(*FREQUENCY_DOMAIN_RANDOM_ +vibration +random +fatigue +INTRODUCTION +VIBRATION_FATIGUE) and SSD fatigue (FREQUENCY_DOMAIN_SSD_ +FATIGUE). +◦ Guard against possible numerical round off that in some cases might result +in unexpected airflow in *MAT_ADD_PORE_AIR. +◦ Added new material *MAT_115_O/*MAT_UNIFIED_CREEP_ORTHO. +◦ *MAT_274: Added support for 2D-solids. New flag (parameter 8 on card +2) is used to switch normal with in-plane axis. +◦ *MAT_255: Fixed bug in plasticity algorithm and changed from total strain +rate to plastic strain rate for stability. Added VP option (parameter 5 on +card 2) for backwards compatibility: VP = 0 invokes total strain rate used +as before. +◦ Added new cohesive material *MAT_279/*MAT_COHESIVE_PAPER to +be used in conjunction with *MAT_274/*MAT_PAPER. +◦ User materials: Added support for EOS with user materials for tshell for- +mulations 3 and 5. +◦ Fixed bug in dyna.str when using EOS together with shells and orthotropic +materials. +◦ *MAT_122: A new version of *MAT_HILL_3R_3D is available. It supports +temperature dependent curves for the Young's/shear moduli, Possion ra- +tios, and Hill's anisotropy parameters. It also supports 2D-tables of yield +curves for different temperatures. Implicit dynamics is supported. The +old version is run if parameter 5 on card 3 is set to 1.0. +◦ Added the phase change option to *MAT_216, *MAT_217, *MAT_218 to +allow material properties to change as a function of location. This capabil- +ity is designed to model materials that change their properties due to ma- +terial processing that is otherwise not modeled. For example, increasing +the mass and thickness due to the deposition of material by spraying. It is +not used for modeling phase changes caused by pressure, thermal loading, +or other mechanical processes modeled within LS-DYNA. +◦ Fix internal energy computation of *MAT_ELASTIC_VISCOPLASTIC_ +THERMAL/MAT_106. +◦ Fix incorrect results or seg fault for *MAT_FU_CHANG_FOAM/MAT_083 +if KCON > 0.0 and TBID.ne.0. +◦ If SIGY = 0 and S = 0 in *MAT_DAMAGE_2/MAT_105, set S = EPS1/200, +where EPS1 is the first point of yield stress input or the first ordinate point +of the LCSS curve. +◦ Set xt = 1.0E+16 as default if user inputs 0.0 for *MAT_ENHANCED_ +COMPOSITE_DAMAGE/MAT_054. Otherwise, random failure of ele- +ments may occur. Implemented for thick shells and solids. +◦ Allow *MAT_ENHANCED_COMPOSITE_DAMAGE/MAT_054 +failure +mechanism to work together with *MAT_ADD_EROSION for shells. +◦ Fix incorrect erosion behavior if *MAT_ADD_EROSION is used with fail- +*MAT_123/MAT_MODIFIED_PIECEWISE_ +for +ure criteria defined +LINEAR_PLASTICITY. +INTRODUCTION +◦ Fix non-failure of triangular elements type 4 using *MAT_ADD_EROSION +with NUMFIP = -100. +◦ Implement scaling of failure strain for *MAT_MODIFIED_PIECEWISE_ +for +LINEAR_PLASTICITY_STOCHASTIC/MAT_123_STOCHASTIC +shells. +◦ Fix +incorrect behavior +*MAT_LINEAR_ELASTIC_DISCRETE_ +BEAM/MAT_066 when using damping with implicit(statics) to explicit +switching. +for +◦ Fix error due to convergence when using *MAT_CONCRETE_EC2/MAT_ +172 in implicit and when FRACRX = 1.0 or FRACRY = 1.0 +◦ Fix incorrect fitting results for *MAT_OGDEN_RUBBER/MAT_077_O if +the number of data points specifed in LCID is > 100. +◦ Fix incorrect fitting results for *MAT_MOONEY-RIVLIN-RUBBER/MAT_ +027 if the number of data points specifed in LCID is > 100. +◦ Fix incorrect forces/moments when preloads are used for *MAT_ +067/NONLINEAR_ELASTIC_DISCRETE_BEAM and the strains changes +sign. +◦ Implement +*MAT_188/MAT_THERMO_ELASTO_VISCOPLASTIC_ +CREEP for 2D implicit analysis. +◦ Support implicit for *MAT_121/MAT_GENERAL_NONLINEAR_1DOF_ +DISCRETE_BEAM. +◦ Fix seg fault when using *DEFINE_HAZ_TAILOR_WELDED_BLANK +with *DEFINE_HAZ_PROPERTIES. +◦ Fix ineffective *MAT_ADD_EROSION if the MID is defined using a alpha- +numeric label. +◦ Fix seg +fault when using +THERMAL/MAT_255 for solids. +*MAT_PIECEWISE_LINEAR_PLASTIC_ +◦ Zero the pressure for *MAT_JOHNSON_HOLMQUIST_JH1/MAT_241 af- +ter it completely fractures, i.e. D>=1.0, under tensile load. +◦ Fix incorrect element failure when using EPSTHIN and VP = 0 for *MAT_ +123/MODIFIED_PIECEWISE_LINEAR_PLASTICITY. +◦ Fix error termination when using adaptive remeshing for 2D analysis with +*MAT_015/JOHNSON_COOK and NIP = 4 in *SECTION_SHELL and +ELFORM = 15. +◦ Fix erosion due to damage, max shear & critical temperature in elastic state +for *MAT_MODIFIED_JOHNSON_COOK/MAT_107 for solids. +◦ Check +diagonal +elements +{OPTION}TROPIC_ELASTIC and +STR+1306, if any of them are negative. +of C-matrix +error +*MAT_002/MAT_ +terminate with message, +of +◦ Fix plastic strain tensor update for *MAT_082/*MAT_PLASTICITY_ +WITH_DAMAGE. +◦ Fix error when using *MAT_144/MAT_PITZER_CRUSHABLE_FOAM +with solid tetahedron type 10. +◦ Fix out-of-range forces after dynamic relaxation when using VP = 1 for +*MAT_PIECEWISE_LINEAR_PLASTICITY and non-zero strain rate pa- +INTRODUCTION +rameters, C & P, and the part goes into plastic deformation during dynam- +ic relaxation. +◦ Fixed unit transformation for GAMAB1 and GAMAB2 on *MAT_DRY_ +FABRIC. We were incorrectly transforming them as stress. +◦ Fixed implicit solutions with shell elements that use *MAT_040 and lami- +nated shell theory. +◦ Fixed the stress calculation in the thermal version of *MAT_077. +◦ Corrected the AOPT = 0 option of ortho/anisotropic materials when use +with skewed solid elements. Previously, the material direction was initial- +ized to be equivalent to the local coordinate system direction. This is not +consistent with the manual for skewed elements which states that the ma- +terial a-axis is in the 1-2 directions for AOPT = 0. This is now fixed and the +manual is correct. +◦ Fixed the AOPT = 0 option of ortho/anisotropic materials for tetrahedral +element forms 10, 13, and 44. +◦ Fixed *MAT_082 for solid elements. An error in the history data was caus- +ing possible energy growth or loss of partially damaged elements. +◦ Modified *MAT_FABRIC/*MAT_034 FORM = 24 so that Poisson's effects +occur in tension only. +◦ Modified *MAT_221/*MAT_ORTHOTROPIC_SIMPLIFIED_DAMAGE to +correct the damage behavior. Prior to this fix, damage was applied to new +increments of stress, but not the stress history, so material softening was +not possible. +◦ Fixed *MAT_106 when used with curves to define the Young's modulus +and Poisson's ratio and when used with thick shell form 5 or 6. The as- +sumed strain field was unreasonable which caused implicit convergence to +fail. +◦ Added 2 new erosion criteria for *MAT_221/*MAT_ORTHOTROPC_ +SIMPLIFIED_DAMAGE. The new options are NERODE = 10: a or b di- +rections failure (tensile or compressive) plus out of plane failure bc or ca. +NERODE = 11: a or b directions failure (tensile only) plus out of plane +failure bc or ca. +◦ Added a new option for shell *MAT_022/*MAT_COMPOSITE_DAMAGE. +When ATRACK = 1, the material directions will follow not only element +rotation, but also deformation. This option is useful for modeling layered +composites, that have material a-directions that vary by layer, by allowing +each layer to rotate independently of the others. Within each layer, the b- +direction is always orthogonal to the a-direction. +◦ Fixed the TRUE_T option on *MAT_100 and *MAT_100_DA. If the weld +connects shells with different thickness and therefore different bending +stiffness, the scheme used by TRUE_T to reduce the calculated moment +could behave somewhat unpredictably. With the fix, TRUE_T behaves +much better, both for single brick welds and brick assemblies. +INTRODUCTION +◦ Added a warning message and automatically switch DMGOPT > 0 to +DMGOPT = 0 on *MAT_FABRIC when RS < EFAIL or RS = EFAIL. This +prevents a problem where weld assemblies did not fail at all when RS = 0. +◦ *MATs 9, 10, 11, 15, 88, and 224 are now available for thick shells, however +only *MATs 15, 88, and 224 are available for the 2D tshell forms 1,2, and 6. +◦ Added thick shell support for the STOCHASTIC option of *MATs 10, 15, +24, 81, and 98. +◦ Added support for *MAT_096 for several solid element types including +ELFORMs 3, 4, 15, 18, and 23. +◦ Added a MIDFAIL keyword option for *MAT_024, (MAT_PIECEWISE_ +LINEAR_PLASTICITY). With this option, element failure does not occur +until the failure strain is reached in the mid plane layer. If an even number +of layers is used, then the failure occurs when the 2 closest points reach the +failure strain. +◦ Enabled *MATs 26 and 126 (HONEYCOMB) to be used with thick shell +forms 3, 5, and 7. These was initialized incorrectly causing a zero stress. +◦ Enabled *MAD_ADD_EROSION to be used with beams that have user de- +fined integration. Memory allocation was fixed to prevent memory errors. +◦ Enabled OPT = -1 on *MAT_SPOTWELD for solid elements. +◦ Enabled thick shells to use *MATs 103 and 104 in an implicit solution. +These materials were lacking some data initialization so they would not +converge. +◦ Enabled solid elements with user-defined orthotropic materials to work +with the INTOUT and NODOUT options on *DATABASE_EXTENT_ +BINARY. The transformation matrix was stored in the wrong place caus- +ing strain and stress transformations to fail. +◦ Enabled *MAT_017 to run with thick shell forms 3 and 5. Neither element +was initialized correctly to run materials with equations of state. +◦ Add degradation factors and strain rate dependent strength possibility for +*MAT_054/*MAT_ENHANCED_COMPOSITE_DAMAGE solids. +◦ Fixed bug +in *MAT_058/*MAT_LAMINATED_COMPOSITE_FABRIC +when used with strain-rate dependent tables for stiffnesses EA, EB and +GAB and LAMSHT = 3. +◦ Add strain rate dependency of ERODS in *MAT_058. +◦ Add possibility to use *DEFINE_FUNCTION for *MAT_SPOTWELD_ +DAMAGE_FAILURE (*MAT_100), OPT = -1/0. If FVAL = FunctionID, +then a *DEFINE_FUNCTION expression is used to determine the weld +failure criterion using the following arguments: func (N_rr, N_rs, N_rt, M_ +rr, M_ss, M_tt). +◦ Store tangential and normal separation (delta_II & delta_I) as history vari- +ables 1&2 of *MAT_138/*MAT_COHESIVE_MIXED_MODE. +◦ Add second normalized traction-separation load curve (TSLC2) for Mode +II in *MAT_186/*MAT_COHESIVE_GENERAL. +INTRODUCTION +◦ Fixed bug +in using +*MAT_157/*MAT_ANISOTROPIC_ELASTIC_ +PLASTIC with IHIS.gt.0 for shells. Thickness strain update d3 was not cor- +rect and plasticity algorithm failed due to typo. +◦ Fixed bug in *MAT_157 for solids: This affected the correct stress trans- +in *DATABASE_ +formation for post-processing using CMPFLG = 1 +EXTENT_BINARY. +◦ Fixed bug in *MAT_225 (*MAT_VISCOPLASTIC_MIXED_HARDENING) +when using Table-Definition together with kinematic hardening. +◦ Add load curves for rate dependent strengths (XC, XT, YC, YT, SC) in +*MAT_261/*MAT_LAMINATED_FRACTURE_DAIMLER_PINHO (shells +only). +◦ Add table definition for LCSS for rate dependency in *MAT_261 (shells on- +ly). +◦ Add load curves for rate dependent strengths (XC, XCO, XT, XTO, YC, YT, +*MAT_262/*MAT_LAMINATED_FRACTURE_DAIMLER_ +SC) +CAMANHO (shells only). +in +◦ Fixed bug when using *MAT_261 or *MAT_262 solids (ELFORM = 2). +◦ Add load curves for SIGY and ETAN for rate dependency of *MAT_262 +(shells only) +◦ *MAT_021_OPTION + Fixed a bug for defining different orientation angles through the +thickness of TSHELL elements (formulations 2 and 3) + Added new option CURING: + Two additional cards are read to define parameters for curing kinet- +ics. Formulation is based on Kamal's model and considers one ODE +for the state of cure. + State of cure does not affect the mechanical parameters of the materi- +al. + CTE's for othotropic thermal expansione can be defined in a table +with respect to state of cure and temperature. + An orthotropic chemical shrinkage is accounted for. +◦ *MAT_REINFORCED_THERMOPLASTICS_OPTION +(*MAT_249_ +OPTION): + Fiber shear locking can be defined wrt to the fiber angle or shear an- +gle. + Output of fiber angle to history variables. + Simplified input: Instead of always reading 8 lines, now the user only +has to specify data for NFIB fibers. + Added fiber elongation to history variables in *MAT_249 for pospro- +cessing. + New Option UDFIBER (based on a user defined material by BMW): +INTRODUCTION +• Transversely isotropic hyperelastic formulation for each fi- +ber family . +• Anisotropic bending behavior based on modified transverse +shear stiffnesses. +• Best suited for dry NCF's. +◦ *MAT_GENERALIZED_PHASE_CHANGE (*MAT_254): + New material that is a generalized version of *MAT_244 with appli- +cation to a wider range of metals. + Up to 24 different phases can be included. + Between each of the phases, the phase transformation can be defined +based on a list of generic transformation laws. For heating JMAK and +Oddy are implemented. For cooling Koistinen-Marburger, JMAK +and Kirkaldy can be chosen. + Constant parameters for the transformations are given as 2d tables, +parameters depending on temperature (rate) or phase concentration +employ 3d tables. + Plasticity model (temperature and strain rate dependent) similar to +MAT_244. + Transformation induced strains. + TRIP algorithm included. + Temperature dependent mixture rules. + Parameter 'dTmax' that defines the maximum temperature increment +within a cycle. If the temperature difference at a certain integration +point is too high, local subcycling is performed. + Implemented for explicit/implicit analysis and for 2d/3d solid ele- +ments. +◦ *MAT_ADHESIVE_CURING_VISCOELASTIC (*MAT_277): + New material implementation including a temperature dependent +curing process of epoxy resin based on the Kamal-Sourour-model. + Material formulation is based on *MAT_GENERAL_VISCOELASTIC. + Viscoelastic properties defined by the Prony series, coefficients as +functions of state of cure. + Chemical and thermal shrinkage considered (differential or secant +formulations). + Available for shell and solid elements. + Can be used in combination with *MAT_ADD_COHESIVE. + Implemented for explicit and implicit analysis. + An incremental and a total stress calculation procedure available. +◦ Enable *MAT_ADD_EROSION to be safely used with material models that +have more than 69 history variables, for now the new limit is 119. +INTRODUCTION +◦ Use correct element ID for output of failed solid elements when GISSMO +(*MAT_ADD_EROSION) is used with *CONTROL_DEBUG. +◦ Improve performance of GISSMO (*MAT_ADD_EROSION with ID- +AM = 1), especially when used with *MAT_024, no other failure criteria, +shell elements, and DMGEXP = 1 or 2. Allows speed-up of 10 to 20 per- +cent. +◦ Add new keyword *MAT_ADD_GENERALIZED_DAMAGE. It provides +a very flexible approach to add non-isotropic (tensorial) damage to stand- +ard materials in a modular fashion. Solely works with shell elements at the +moment. +◦ Correct the computation of effective strain for options ERODS < 0 in +*MAT_058 (*MAT_LAMINATED_COMPOSITE_FABRIC) and EFS < 0 in +*MAT_261 +(*MAT_LAMINATED_FRACTURE_ +DAIMLER_...). The shear strain term was twice the size as it should have +been. +*MAT_262 +and +◦ Adjust stiffness for time step calculation in *MAT_076 and subsequent +models (*MAT_176, *MAT_276, ...) to prevent rarely observed instabilities. +◦ Add output of original and fitted curves to messag and separate file +(curveplot_) for *MAT_103. +◦ In *MAT_104 (*MAT_DAMAGE_1), stress-strain curve LCSS can now be +used directly with all FLAG options (-1,0,1,10,11), no fitting. +◦ Correct strain calculation for anisotropic damage in *MAT_104 (*MAT_ +DAMAGE_1) with FLAG = -1. +◦ Initialize stress triaxiality of *MAT_107 (*MAT_MODIFIED_JOHNSON_ +COOK) to zero instead of 1/3. +◦ Avoid negative damage in *MAT_107 (*MAT_MODIFIED_JOHNSON_ +COOK) with FLAG2 = 0 for solid elements. +◦ Rectify the characteristic element length in *MAT_138 (*MAT_COHESIVE_ +MIXED_MODE) for solids type 21 and 22 (cohesive pentas) and shell type +29 (cohesive shell) for "curve" options T < 0 and S < 0. +◦ Correct/improve material tangent for *MAT_181 with PR > 0 (foam op- +tion). +◦ Add possibility to define logarithmically defined strain rate table LCID-T +in material *MAT_187 (*MAT_SAMP-1). +◦ Fix missing offset when using *DEFINE_TRANSFORMATION with load +curve LCID-P in *MAT_187 (*MAT_SAMP-1). +◦ Add reasonable limit for biaxial strength in *MAT_187 with RBCFAC > 0.5 +to avoid concave yield surface. +◦ Improve performance of *MAT_187 to reach speed-up of 10 to 40 percent, +depending on which options are used. +◦ Add new option for *MAT_224 (*MAT_TABULATED_JOHNSON_COOK). +With BETA < 0 not only a load curve but now also a table can be referred +to. The table contains strain rate dependent curves, each for a different +temperature. +INTRODUCTION +◦ Fix for implicit version of *MAT_224 (*MAT_TABULATED_JOHNSON_ +COOK). Computations with shell elements should converge faster now. +◦ *MAT_224 (*MAT_TABULATED_JOHNSON_COOK) can now be used in +implicit even with temperature dependent Young's modulus (parameter +E < 0). +◦ Always store the Lode parameter as history variable #10 in *MAT_224 +(*MAT_TABULATED_JOHNSON_COOK), not just for LCF being a table. +◦ Variable LCI of *MAT_224 / *MAT_224_GYS can now refer to a *DEFINE_ +TABLE_3D. That means the plastic failure strain can now be a function of +Lode parameter (TABLE_3D), triaxiality (TABLE), and element size +(CURVE). +◦ For thick shells type 1 and 2, the element size in *MAT_224 is now correct. +◦ Add new option for definition of parameters FG1 and FG2 in *MAT_240 +(*MAT_COHESIVE_MIXED_MODE_ELASTOPLASTIC_RATE). +◦ Add new option to *MAT_240: new load curves LCGIC and LCGIIC define +fracture energies GIC and GIIC as functions of cohesive element thickness. +GIC_0, GIC_INF, GIIC_0, and GIIC_INF are ignored in that case. +◦ Add new feature to *MAT_248 (*MAT_PHS_BMW). Estimated Hocket- +Sherby parameters are written to history variables based on input func- +tions and phase fractions. +◦ Add new option ISLC = 2 to *MAT_248 (*MAT_PHS_BMW) which allows +to define load curves (cooling rate dependent values) for QR2, QR3, QR4, +and all parameters on Cards 10 and 11. +◦ Add new option LCSS to *MAT_252 (*MAT_TOUGHENED_ADHESIVE_ +POLYMER): A load curve, table or 3d table can now be used to define rate +and temperature dependent stress-strain behavior (yield curve). +◦ Fix for *MAT_255, evaluation of 2d tables LCIDC and LCDIT. Negative +temperatures were interpreted as logarithmic rates. +◦ Add new material model *MAT_280 (*MAT_GLASS) for shell elements. It +is a smeared fixed crack model with a selection of different brittle, stress- +state dependent failure criteria and crack closure effects. +◦ *DEFINE_FABRIC_ASSEMBLIES: Assemblies of *MAT_FABRIC part sets +can be specified to properly treat bending of t-intersecting fabrics that are +stitched or sewn together. See ECOAT, TCOAT and SCOAT on *MAT_ +FABRIC_... Bending can only occur within an assembly, aka a part set. +◦ *MAT_USER_DEFINED_MATERIAL_MODELS: In user defined material +models, a logical parameter 'reject' can be set to .true. to indicate to the +implicit solver that equilibrium iterations should be aborted. The criterion +is the choise of the implementor, but it could be if plastic strain increases +by more than say 5% in one step or damage increases too much, whatever +that might render an inaccurate prediction and bad results. Setting this pa- +rameter for explicit won't do anything. +◦ IHYPER = 3 for user shell materials now supports thickness train update, +see *MAT_USER_DEFINED_MATERIAL_MODELS. +INTRODUCTION +◦ *MAT_SIMPLIFIED_RUBBER/FOAM: AVGOPT < 0 is now supported for +the FOAM option, which activates a time averaged strain rate scheme to +avoid noisy response. +◦ MAT_181 is now supported for 2D implicit simulations. +◦ *MAT_ADD_EROSION: + A number of extensions and improvements to the DIEM damage +model were made, IDAM < 0. + General efficiency, it was slow, now it's GOT to be faster. + NCS can be used as a plastic strain increment to only evaluate criteria +in quantifications of plastic strain. + NUMFIP < 0 is employing the GISSMO approach, number of layers +for erosion. + A new ductile damage criterion based on principal stress added +(DMITYP = 4). + MSFLD and FLD can be evaluated in mid or outer layers to separate +membrane and bending instability (P2). + MSFLD and FLD can use an incremental or direct update of instabil- +ity parameter (P3). + Output of integration point failure information made optional (Q2). + Specifying DCTYP = -1 on the damage evolution card will not couple +damage to stress but the damage variable is only calculated and +stored. +◦ *MAT_SMOOTH_VISCOELASTIC_VISCOPLASTIC, *MAT_275: An elas- +tic-plastic model with smooth transition between elastic and plastic mode +is available. It incorporates viscoelasticity and viscoplasticity and is based +on hyper-elastoplasticity so it is valid for arbitrarily large deformations +and rotations. A sophisticated parameter estimation is required to match +test data, it is available for implicit and explicit analyisis but perhaps most- +ly suited for implicit. +◦ *MAT_FABRIC_MAP: Stress map material 34 is equipped with bending +properties identical to that of the form 14 and form -14 version of the fab- +ric. Coating properties are set in terms of stiffness, thickness and yield. +The material is supported in implicit, including optional accounting for the +nonsymmetric tangent. Should be used with bending stiffness on, and +convergence is improved dramatically if geometric stiffness is turned on. +◦ *MAT_084 with predefined units (CONM < 0) is now transformed correct- +ly with INCLUDE_TRANSFORM. +◦ If LCIDTE = 0 in *MAT_121, then LS-DYNA was crashing on some plat- +forms, including Windows. This is fixed. +◦ Fix initialization issues so that PML models can be run with *CASE com- +mands. +◦ *MAT_027 is revised to avoid accuracy issues for single precision executa- +bles. +INTRODUCTION +◦ The nearly imcompressible condition is enhanced for *MAT_027 shell ele- +ments. +◦ Add a new material model as a option for *MAT_165. *MAT_PLASTIC_ +NONLINEAR_KINEMATIC_B is a mixed hardening material model, and +can be used for fatigue analysis. +◦ Output local z-stress in *MAT_037, when *LOAD_STRESS_SURFACE is +used. This was previously calculated and saved as another history varia- +ble. +◦ Add a new material model *MAT_260 (2 forms). + Uses non-associated flow rule and Hill's yield surface; including +strain rate effect and temperate effect. MIT failure criteria is also im- +plemented. + Implemented for solids and shells. + Strain rate sensitivity for solids. + Option to directly input the Pij and Gij values. + Separate the material model *MAT_260 into *MAT_260A and *MAT_ +260B: +• MAT260A=*MAT_STOUGHTON_NON_ASSOCIATED_ +FLOW +• MAT260B=*MAT_MOHR_NON_ASSOCIATED_FLOW + Incorporates FLD into the fracture strain, so as to consider the mesh +size effect. + Calculates the characteristic length of the element for *MAT_260B, so +that an size-dependent failure criterial can be used. + When failure happens for half of the integration points through the +thickness, the element is deleted. +◦ Add Formablitiy Index to *MAT_036, *MAT_037, *MAT_226. +◦ Add new history variables for Formability Index, affecting *MAT_036, +*MAT_037, *MAT_125, *MAT_226. Those new history variables are FI, be- +ta, effective strain. These comes after the 4 regular history variables. +◦ *MAT_036, *MAT_125: New option_NLP is added to evaluate formability +under non-linear strain paths. User inputs a forming limit diagram (FLD), +and Formablitiy Index (F.I.) will be automatically converted to effective +stain vs. beta based space. +• MPP +◦ Fix problem of MPP pre-decomposition that can occur if the local directory +specified in the pfile has very different lengths in the initial run vs the ac- +tual run The difference resulted in a line count difference in the size of the +structured files created, throwing off the reading of the file in the actual +run. +◦ Straighten out some silist/sidist issues in MPP decomp: +INTRODUCTION + silist and sidist outside of a "region" in the pfile are no longer sup- +ported, and an error message is issued which suggests the use of "re- +gion { silist" instead. + They have been undocumented for several years (since "region" was +introduced), and had other issues. +◦ Fix +the keywords, CONTROL_MPP_DECOMPOSITION_CONTACT_ +and CONTROL_MPP_DECOMPOSITION_CONTACT_ +DISTRIBUTE +ISOLATE, which were not treating each contact interface individually (as +the manual states), but collectively. +◦ Fix for MPP decomp of part sets. +◦ Fixed *CONTROL_MPP_PFILE (when used inside an include file) so that it +honors ID offsets from *INCLUDE_TRANSFORM for parts, part sets, and +contact ids referenced in "decomp { region {" specifications. Furthermore, +such a region can contain a "local" designation, in which case the decom- +position of that region will be done in the coordinate system local to the in- +clude file, not the global system. For example: +*CONTROL_MPP_PFILE +decomp { region {partset 12 local c2r 30 0 -30 0 1 0 1 0 0}} +would apply the c2r transformation in the coordinate system of the include +file, which wasn't previously possible. The local option can be useful even +if there are no such transformations, as the "cubes" the decomposition uses +will be oriented in the coordinate system of the include file, not the global +system. Furthermore, the following decomposition related keywords now +have a_LOCAL option, which has the same effect: + *CONTROL_MPP_DECOMPOSITION_PARTS_DISTRIBUTE_ +LOCAL + *CONTROL_MPP_DECOMPOSITION_PARTSET_DISTRIBUTE_ +LOCAL + *CONTROL_MPP_DECOMPOSITION_ARRANGE_PARTS_LOCAL + *CONTROL_MPP_DECOMPOSITION_CONTACT_DISTRIBUTE_ +LOCAL +◦ Revert revision 86884, which was: + "MPP: change to the decomposition behavior of *CONTROL_MPP_ +DECOMPOSITION_PARTS_DISTRIBUTE +*CONTROL_MPP_DECOMPOSITION_PARTSET_DISTRIBUTE +*CONTROL_MPP_DECOMPOSITION_ARRANGE_PARTS +in the case where a decomposition transformation is also used. Previ- +ously, any such regions were distributed without the transformation +being applied. This has been fixed so that any given transformation +applies to these regions also. So now the transformations will NOT +INTRODUCTION +apply to these keywords. Really, the "region" syntax should be used +together with *CONTROL_MPP_PFILE as it is more specific. +◦ Modify behavior of DECOMPOSITION_AUTOMATIC so that if the initial +velocity used is subject to *INCLUDE_TRANSFORM, the transformed ve- +locities are used. +◦ Fix MPP decomposition issue with "decomp { automatic }" which was not +honored when in the pfile. +◦ Save hex weld creation orientation to the pre-decomposition file so that the +subsequent run generates the welds in the same way. +◦ Fix for MPP not handling element deletion properly in some cases at de- +composition boundaries. +◦ Add new pfile option "contact { keep_acnodes }" which does NOT exclude +slave nodes of adaptive constraints from contact, which is the default be- +havior. (MPP only.) +◦ MPP Performance-Related Improvements: + Allow user input of *LOAD_SEGMENT_FILE through familied files. + Bug fix for *LOAD_SEGMENT_FILE to get correct time history data +for pressure interpolation. + Output two csv files for user to check MPP performance: +• +load_profile.csv: general load balance +• cont_profile.csv: contact load balance + Allow user to control decomp/distribution of multiple airbags using +*CONTROL_MPP_DECOMPOSITION_ARRANGE_PARTS + memory2 = option on *KEYWORD line + Disable unreferenced curves after decomposition using *CONTROL_ +MPP_DECOMPOSITION_DISABLE_UNREF_CURVES. This applies +to the curves used in the following options to speed up the execution +several times. +• +• +• +• +*BOUNDARY_PRESCRIBED_MOTION_NODE +*LOAD_NODE +*LOAD_SHELL_ELEMENT +*LOAD_THERMAL_VARIABLE_NODE +◦ Bug fix for *CONTROL_MPP_DECOMPOSITION_SHOW with *AIRBAG_ +PARTICLE. +◦ Fix cpu dependent results when using function RCFORC() in *DEFINE_ +CURVE_FUNCTION. This affects MPP only. +◦ Fix hang up when using *DEFINE_CURVE_FUNCTION with element +function BEAM(id,jflag,comp,rm) and running MPP with np > 1. +◦ *CONTROL_MPP_DECOMPOSITION: The cpu cost for solid elements -1 +and -2 are accounted for in the mpp domain decomposition. +◦ Fix bug in *CONTROL_MPP_IO (Windows platform only) related to insuf- +ficient administrative privileges for writing tmp file on root drive. +◦ Revise l2a utility on Windows platform to create identical node output +INTRODUCTION +format as Linux. +• Output +◦ Fix for MPP external work when bndout is output and there are +*BOUNDARY_PRESCRIBED_MOTION_RIGID commands in the input. +◦ Fixed the output of forces and associated energy due to *LOAD_RIGID_ +BODY for both explicit and implicit (*DATABASE_BNDOUT). +◦ Fixed stress and strain output of thick shells when the composite material +flag is set on *DATABASE_EXTENT_BINARY. The transformation was +backwards. +◦ If the size of a single plot state was larger than the d3plot size defined by +x= on the execution line, the d3plot database may not be readable +by LS-PrePost. This issue is now fixed. +◦ *DATABASE_PROFILE: Output data profiles for beams (TYPE = 5) and +add density as DATA = 20. +◦ New option HYDRO = 4 on *DATABASE_EXTENT_BINARY. Outputs 7 +additional variables: the same 5 as HYDRO = 2 plus volumetric strain (de- +fined as Relative Volume - 1.0) and hourglass energy per unit initial vol- +ume. +◦ Fix for binout output of swforc file which can get the data vs. ids out of +sync when some solid spotwelds fail. +◦ Fix for d3plot output of very large data sets in single precision. +◦ Fix for output of bndout data for joints in MPP, which was writing out in- +correct data in some cases. +◦ Added new option *INTERFACE_SPRINGBACK_EXCLUDE to exclude +selected portions from the generated dynain file. +◦ Add a new option to *INTERFACE_COMPONENT_FILE to output only 3 +degrees of freedom to the file, even if the current model has 6. +◦ Minor change to how pressure is computed for triangles in the INTFOR +output. +◦ Fix MPP output issue with intfor file. +◦ Fixes for writing and reading of dynain data in LSDA format. +◦ Corrected the summation of rigid body moments for output to bndout for +some special cases in MPP. +◦ Corrected the output to d3iter when 10 node tets are present (D3ITCTL on +*CONTROL_IMPLICIT_SOLUTION). +◦ Enhanced implicit collection of moments for the rcforc file. +◦ For implicit, convert spc constraint resultant forces to local coordinate sys- +tem for output. Also corrected Implicit's gathering of resultant forces due +to certain SPC constraints. +◦ Fixed the gathering of resultant forces in implicit for prescribed motion on +nodes of a constrained rigid body for output to bndout. +INTRODUCTION +◦ Added output of modal dynamics modal variables to a new file moddy- +is controlled by *CONTROL_IMPLICIT_MODAL_ + Output +nout. +DYNAMICS. +◦ Corrected the output of resultant forces for Implicit Linear analysis. Cor- +rected the output of resultant forces for MPP executions. These enhance- +ments affect a number of ASCII files including bndout. +◦ The following 4 enhancements are to the eigensolvers, including that used +for *CONTROL_IMPLICIT_EIGENVALUE. + Standardized and enhance the warning/error messages for Implicit +eigensolution for the case where zero eigenmodes are computed and +returned in eigout and d3eigv. + Added nonsymmetric terms to the stiffness matrix for the implicit ro- +tational dynamics eigenanalysis. This allows brake squeal analysis +with the contact nonsymmetric terms from mortar contact now in- +cluded in the analysis. + Updated implicit eigensolution for problems with unsymmetric stiff- +ness matrices. Fixed Rotational Dynamics eigensolution to work cor- +rectly when first order matrix (W) is null. . + Added the eigensolution for problems with stiffess (symmetric or un- +symmetric), mass, and damping. +◦ Improve Implicit's treatment of constrained joints to account for rounding +to *CONSTRAINED_JOINT with *CONTROL_ + Applicable +errors. +IMPLICIT_GENERAL. +◦ For implicit springback, zero out the forces being reported to rcforc for +those contact interfaces disabled at the time of springback. Also enhance +the removal of contact interfaces for springback computations. For +*INTERFACE_SPRINGBACK. +◦ *DATABASE_RECOVER_NODE is available to recover nodal stress. +◦ Fix a bug for detailed stress output, eloutdet, for SOLID type 18. +◦ Support new format of interface force files for ALE, DEM, and CPM. LS- +PrePost can display the correct label for each output component. +◦ Added *DATABASE_NCFORC_FILTER option to allow the NCFORC data +to be filtered using either single pass or double pass Butterworth filtering +to smooth the output. + Added the same filtering capability to +*DATABASE_BINARY_D3PLOT. This capability is specified on the addi- +tional card for the D3PLOT option and does not require "_FILTER" in the +keyword input. +◦ Fix incorrect mass properties for solids in SSSTAT file when using +*DATABASE_SSSTAT_MASS_PROPERTIES. +◦ Fix seg fault during writing of dynain file if INSTRN = 1 in *INTERFACE_ +SPRINGBACK and STRFLG.ne.0 in *DATABASE_EXTENT_BINARY and +the +SPRINGBACK. Also output warning message, KEY+1104. +comes +after +*INTERFACE_ +◦ Fix zero strain values output +to curvout +for *DEFINE_CURVE_ +FUNCTION using function, ELHIST, for solid elements. +◦ Fix missing parts in d3part when MSSCL = 1 or 2 in *DATABASE_ +EXTENT_BINARY. +◦ Fix incorrect damping energy computation for glstat. +◦ Fix incorrect part mass in d3plot for shells, beams & thick shells. +◦ Fix incorrect curvout values when using BEAM(id,jflag,comp,rm) for +*DEFINE_CURVE_FUNCTION and if the beam formulation is type 3, i.e. +truss. +◦ Fix incorrect output to curvout file if using ELHIST in *DEFINE_CURVE_ +FUNCTION for shells. +◦ Output stresses for all 4 intg points to eloutdet for cohesive element types +19 & 20. +◦ Fix +incorrect rotational displacement to nodout when REF = 2 +in +*DATABASE_HISTORY_NODE_LOCAL. Affects MPP only. +◦ Fix incorrect strains output to elout for shell type 5 and when NIP > 1. +◦ Fix incorrect acceleration output to nodout file when IACCOP = 1 in +*ELEMENT_SEATBELT_ +IGRAV = 1 +in +*CONTROL_OUTPUT and +ACCELEROMETER. +◦ Fix corrupted d3plot when RESPLT = 1 +in *DATABASE_EXTENT_ +BINARY and idrflg.ge.5 in *CONTROL_DYNAMIC_RELAXATION. +◦ Fix missing element connectivities in nastin file when using *INTERFACE_ +SPRINGBACK_NASTRAN_NOTHICKNESS. +fault when using +seg +◦ Fix +*DATABASE_BINARY_D3PART with +*CONTACT_TIED_SHELL_EDGE_TO_SURFACE. This affects SMP only. +◦ Fix incorrect output to bndout when using multiple *LOAD_NODE_ +POINT for the same node and running MPP with ncpu > 1. +◦ Fix incorrect dyna.inc file when using *MAT_FU_CHANG_FOAM/MAT_ +83, *DEFINE_COORDINATE_NODES, and *CONSTRAINED_JOINT_ +STIFFNESS_GENERALIZED with *INCLUDE_TRANSFORM. +◦ Fix IEVERP in *DATABASE_EXTENT_D3PART which was not honored in +writing out d3part files. +◦ Fix incorrect stresses written out to dynain for thick shells with formula- +tions 1,2 and 4. +◦ Fix incorrect output to disbout data for discrete beams. +◦ Fix incorrect output to binary format of disbout. Affects SMP only. +◦ Fix error when writing initial stresses for thick shells to dynain. Affects +MPP only. +◦ Fix thick shells strain output to dynain. +◦ Fix incorrect writing of material data to dyna.str for *MAT_SEATBELT +when using long = s. +◦ Fix coordinate/disp output to d3plot of *CONSTRAINED_NODAL_ +RIGID_BODY's pnode. +INTRODUCTION +◦ Fixed the initial d3plot state in SMP runs when tied contact is used with +theCNTCO parameter on *CONTROL_SHELL. The geometry was wrong +in that state. +◦ Add cross section forces output (*DATABASE_SECFORC) for cohesive el- +ements ELFORM type 19, 20, 21, and 22. +◦ Slight increase of precision for values in nodout file. +◦ Add new option FSPLIT to *INTERFACE_SPRINGBACK_LSDYNA to +split the dynain file into two files (geometry and initial values). +◦ *DEFINE_MATERIAL_HISTORIES: New keyword for organizing material +history outputs, currently only for solids, shells and beams and the d3plot +output but to be extended to tshells and ascii/binout. The purpose is to +customize +that otherwise are output via +NEIPS/NEIPH/NEIPB on *DATABASE_EXTENT_BINARY, to avoid vari- +able conflict and large d3plots and thus facilitate post-processing of these +variables. Currently available in small scale but to be continuously ex- +tended. +the history variables +◦ Fixed bug affecting IBINARY = 1 (32 bit ieee format) in *DATABASE_ +FORMAT. This option was not working. +◦ Fixed incorrect printout of node ID for *ELEMENT_INERTIA. +◦ Increased the header length to 80 for the following files in binout: matsum, +nodout, spcforc, ncforc +◦ Fixed bug in which d3msg was not written for SMP. +◦ The d3plot output for rigid surface contact was incorrect for MPP. +◦ Fixed bugs when when using curve LCDT to control d3plot output. +◦ Fixed abnormal increase in d3plot size caused by outputting velocity and +acceleration when data compression is on. +◦ Added new variable GEOM in *CONTROL_OUTPUT for chosing geome- +try or displacement in d3plot, d3part, and d3drlf. +◦ Added command line option "msg=" to output warning/error descrip- +tions. See MSGFLG in *CONTROL_OUTPUT for alternate method of re- +questing such output. Accepted values for "msg=" are message# or all. + message#, e.g., KEY+101 or 10101. This option will print the er- +ror/warning message to the screen. + all. this option will print all error/warning messages to d3msg file. +◦ Fixed bug for *DATABASE_BINARY_D3PROP file if adaptivity used. The +error caused blank d3prop output. +◦ *DATABASE_HISTORY_SHELL_SET +*CONTROL_ +ADAPTIVITY caused error 20211. The error involves the BOX option be- +ing used for shell history output. +combined with +◦ Added *INTEGRATION... data to d3prop. +INTRODUCTION +• Restarts +◦ Fix bug when deleted uniform pressure (UP) airbag during simple restart. +◦ Fix for index error that could cause problems for accelerometers during +full deck restart in MPP. +◦ Fix for MPP output of LSDA interface linking file when restarting from a +dump file. +◦ Fix incorrect strains in d3plot after restart when STRLG > 1. +◦ Fix incorrect velocity initialization for SMP full deck restart when using +◦ *INITIAL_VELOCITY_GENERATION +*INITIAL_VELOCITY_ +and +GENERATION_START_TIME. +◦ Fix incorrect behavior of *CONTACT_ENTITY in full deck restart. +◦ Fix incorrect full deck restart analysis if initial run was implicit and the full +deck restart run is explicit. +◦ Fix +ineffective boundary condition +for *MAT_RIGID when using +*CHANGE_RIGID_BODY_CONSTRAINT with *RIGID_DEFORMABLE_ +R2D for small deck restart. +◦ Fix initialization of velocities of *MAT_RIGID_DISCRETE nodes after re- +start using *CHANGE_VELOCITY_GENERATION. +◦ Fix internal energy oscillation after full deck restart when using +*CONTACT_TIED_SURFACE_TO_SURFACE_OFFSET with TIEDID = 1 in +optional card D. This affects SMP only. +◦ Corrected bug affecting full restart that +included any change to +node/element IDs. This bug has existed since version R6. +◦ Fixed bug affecting d3plot times following fulldeck restart with curve in +SMP. +◦ Fixed bug in simple restart: *INTERFACE_COMPONENT_FILE forgets the +filename and writes to infmak instead. +• *SENSOR +◦ Enable full restart for *SENSOR. +◦ Add optional filter ID to SENSORD of *DEFINE_CURVE_FUNCTION. +◦ Enable LOCAL option of *CONSTRAINED_JOINT to be used with +*SENSOR_DEFINE_FORCE. +◦ Fix a MPP bug that happens when *SENSOR_DEFINE_NODE has a de- +fined N2. +◦ *SENSOR_CONTROL: + Fix a bug for TYPE = JOINTSTIF + Fix a MPP bug for TYPE = PRESC-MOT when the node subject to +prescribed motion is part of a rigid body + Add TYPE = BELTSLIP to control the lockup of *ELEMENT_ +SEATBELT_SLIPRING. + Add TYPE = DISC-ELES to delete a set of discrete elements. +INTRODUCTION +◦ Add FTYPE = CONTACT2D to to *SENSOR_DEFINE_FORCE to track the +force from *CONTACT_2D. +◦ Add the variable SETOPT for *SENSOR_DEFINE_NODE_SET and +*SENSOR_DEFINE_ELEMENT_SET to sense and process data from a node +set or element set, resp., resulting in a single reported value. +◦ *SENSOR can be used to control *CONTACT_GUIDED_CABLE. +◦ Fix a bug related to *SENSOR_DEFINE_FUNCTION triggered by more +than 10 sensor definitions. +• SPG (Smooth Particle Galerkin) +◦ *SECTION_SOLID_SPG +(KERNEL = 1): The dilation parameters +(DX,DY,DZ) of SPG Eulerian kernel are automatically adjusted according +to the local material deformation to prevent tensile instability. +• SPH (Smooth Particle Hydrodynamics) +◦ Retain user IDs of SPH particles in order to ensure consistent results when +changing the order of include files. +◦ Add feature to inject SPH particles, *DEFINE_SPH_INJECTION. +◦ Added support of various material models for 2D and 3D SPH particles: + *MAT_098 (*MAT_SIMPLIFIED_JOHNSON_COOK) + *MAT_181 (*MAT_SIMPLIFIED_RUBBER) + *MAT_275 (*MAT_SMOOTH_VISCOELASTIC_VISCOPLASTIC) +◦ Added support of *DEFINE_ADAPTIVE_SOLID_TO_SPH for 2D shell el- +ements and 2D axisymmetric shell elements. +◦ When using *DEFINE_ADAPTIVE_SOLID_TO_SPH, eliminated duplicate +kinetic energy calculation for SPH hybrid elements (both SPH particles and +solid elements contributed kinetic energy into global kinetic energy). +◦ Added support of second order stress update (OSU = 1 in *CONTROL_ +ACCURACY keyword) for 2D and 3D SPH particles. This is necessary for +simulation of spinning parts. +◦ Added ISYMP option in *CONTROL_SPH to define as a percentage of +original SPH particles the amount of memory allocated for generation of +SPH ghost nodes used in *BOUNDARY_SPH_SYMMETRY_PLANE. +◦ Fixed unsupported part and part set option in *BOUNDARY_SPH_FLOW. +◦ Fixed unsupported ICONT option from *CONTROL_SPH when combined +with *BOUNDARY_SPH_FLOW. +◦ *DEFINE_SPH_TO_SPH_COUPLING: Output contact forces between two +SPH parts (x,y,z and resultant forces) into sphout. The forces can be plotted +by LS-PrePost. +◦ *CONTACT_2D_NODE_TO_SOLID: Added bucket sort searching algo- +rithm to speed up the process of finding contact pairs between SPH parti- +cles and solid segments. +INTRODUCTION +• Thermal +◦ Corrected a long standing bug in MPP thermal associated with spotwelds +(*CONSTRAINED_SPOTWELD) using thermal linear solver option 11 or +greater. The spotweld loads were not being loaded correctly due to an in- +dexing issue in MPP. +◦ Fix for thermal with *CASE. +◦ Fix MPP support for thermal friction in SOFT = 4 contact. +◦ Fixed bug where thermal solver gives a non-zero residual even though no +loads are present. +◦ Added SOLVER = 17 +(GMRES solver) +to *CONTROL_THERMAL_ +SOLVER for the conjugate heat transfer problem. The GMRES solver has +been developed as an alternative to the direct solvers in cases where the +structural thermal problem is coupled with the fluid thermal problem in a +monolithic approach using the ICFD solver. A significant savings of calcu- +lation time can be observed when the problem reaches 1M elements. This +solver is implemented for both SMP and MPP. +◦ *CONTACT_(option)_THERMAL +(3D contact only): Add variable +FRTOHT to specify fraction of frictional energy applied to slave surface. It +follows that 1.-FRTOHT is applied to master surface. Default is 0.5 which +gives a 50% - 50% split between the slave and master surfaces which was +hardwired in prior releases. +◦ First release of AUTOMATIC_SURFACE_TO_SURFACE_TIED_WELD_ +THERMAL. + This will only work when used with BOUNDARY_ +THERMAL_WELD. This combination of keywords will activate a condi- +tion where sliding contact will become tied contact on cooldown when the +temperature of the segments in contact go above an input specified tem- +perature limit during welding. +◦ *LOAD_THERMAL_D3PLOT: The d3plot data base was changed such that +the 1st family member contains control words, geometry, and other control +entities. Time state data begins in the 2nd family member. This change al- +lows the new d3plot data structure to be read in by LS-DYNA when using +the *LOAD_THERMAL_D3PLOT keyword. This change is not backward +compatible. The old d3plot data structure will no longer be read correctly +by LS-DYNA. +◦ Synchronize data in TPRINT for SMP and MPP: + Fixed output to tprint/binout for thermal contact. + Fixed part IDs for part energies. + Fixed format of TPRINT file generated by l2a. +◦ Fixed handling of start time defined with *CONTROL_START for thermal +solver. +◦ Change the maximum number of *LOAD_HEAT_CONTROLLER defini- +tions from 10 to 20. +INTRODUCTION +◦ Added a third parameter to the TIED_WELD contact option. The parame- +ter specifies heat transfer coefficient h_contweld for the welded contact. +Before welding, the parameter from the standard card of the thermal con- +tact is used. +◦ Parameter FRCENG supported for mortar contact to yield heat in coupled +thermomechanical problems. +• XFEM (eXtended Finite Element Method) +◦ Added ductile failure to XFEM using critical effective plastic strain as fail- +ure criterion. +• Miscellaneous +◦ Support *SET_NODE_GENERAL PART with SPH and DES. +◦ *DEFINE_POROUS_...: Compute the coefficients A and B with a user de- +fined routine in dyn21.F. +bugs +◦ Fixed +in +Staged +Construction +(*DEFINE_STAGED_ +CONSTRUCTION_PART): + Staged construction not working on SMP parallel. Symptoms could +include wrong elements being deleted. + Staged construction with beam elements of ELFORM = 2: when these +beams are dormant, they could still control the time step. + Staged construction with *PART_COMPOSITE. The bug occurred +when different material types were used for different layers within +the same part, and that part becomes active during the analysis. The +symptom of the bug was that stresses and/or history variables were +not set to zero when the part becomes active. +◦ Bugs fixed in *DAMPING_FREQUENCY_RANGE_DEFORM: + Incorrect results when large rigid body rotations occur. + If RYLEN on *CONTROL_ENERGY = 2, the energy associated with +this damping should be included in the Internal Energy for the rele- +vant part(s). This energy was being calculated only if there was also +*DAMPING_PART_STIFFNESS in the model. Now fixed - the damp- +ing energy will be included in the internal energy whenever +RYLEN = 2. +◦ Fixed NID option of *DEFINE_COORDINATE_VECTOR (bug occurred in +MPP only). +◦ Fix lsda open mode to require only minimal permissions to avoid unneces- +sary errors, for example if using an interface linking file that is read only. +◦ Fix for DPART processing (*SET_..._GENERAL) for solid and thick shell +elements. +INTRODUCTION +◦ Fix for JOBID > 63 characters. +◦ Fix input processing problem (hang) that could happen in some unusual +cases if encrypted *INCLUDE files are used. +◦ Fix interaction of *CASE with jobid = on command line, so the jobid on the +command line is combined with the generated case ids instead of being ig- +nored. +◦ *INCLUDE_NASTRAN: + Integration defaults to Lobatto for Nastran translator. + The default number of integration points is set to 5 for Nastran trans- +lator. +◦ Issue +error message +TRANSFORMATION is specified. +and +terminate when +illegal +*DEFINE_ +◦ Add OPTION = POS6N to *DEFINE_TRANSFORMATION to define trans- +formation with 3 reference nodes and 3 target nodes. +◦ Add OPTION = MIRROR to *DEFINE_TRANSFORMATION. +◦ Fix a bug that could occur when adapted elements are defined in a file in- +cluded by *INCLUDE_TRANSFORM. +◦ Fix a bug that could occur when *BOUNDARY_SPC_SYMMETRIC_ +PLANE is used together with *INCLUDE_TRANSFORM. +◦ Fix a bug that occurs when *DEFINE_BOX is included by *INCLUDE_ +TRANSFORM. +◦ Make *SET_NODE_COLLECT work together with *NODE_SET_MERGE. +◦ Fix incorrect shell set generated when using *SET_SHELL_GENERAL with +OPTION = PART. +◦ Add error trap for *SET_PART_LIST_GENERATE_COLLECT to catch +missing part IDs. +◦ Fixed bug in *INCLUDE_TRANSFORM for adaptive case if JOBID is used. +◦ Fixed bug in memory allocation for *DEFINE_CURVE if total number +of points in +curve is more than 100. +◦ Fixed bug with *INCLUDE_TRANSFORM and *CONTROL_ADAPTIVITY +due to an *INCLUDE inside *INCLUDE_TRANSFORM file. Added new + The *NODE, +files: adapt.inc# +*ELEMENT_SHELL and *ELEMENT_SOLID are removed from include +file. +for *INCLUDE_TRANSFORM +file. +◦ Fixed bug for DPART option in *SET_SEGMENT_GENERAL. DPART op- +tion was treated as PART option before. +◦ Fixed failure of *PARAMETER definition in long format. +◦ Fixed error in reading solid id for *SET_SOLID_GENERAL. +◦ Ignore any nonexistant part set IDs in *SET_PART_ADD. +◦ Fix bug in which sense switches sw2 and sw4 don't work when the output +interval for glstat is small. +◦ Fixed bug if *DEFINE_CURVE is used to define adaptivity level. +INTRODUCTION +◦ Three new keywords are implemented in support of user defined subrou- +tines: *MODULE_PATH[_RELATIVE], MODULE_LOAD, MODULE_USE. + The MODULE feature allows users to compile user subroutines into +dynamic libraries without linking to the LS-DYNA main executable. + The dynamic libraries are independent from the main executable and +do not need to be recompiled or linked if the main executable is up- +dated. + This feature loads multiple dynamic libraries on demand as specified +in the keywords. + Without the MODULE feature, only one version of each umat (such +as umat41) can be implemented. With the MODULE feature, most +umat subroutines can be have multiple versions in multiple dynamic +libraries, and used simultaneously. + The MODULE feature supports all user subroutines. + The LS-DYNA main executable may also run without any dynamic +libraries if no user subroutines are required. +Capabilities added to create LS-DYNA R10.0: +See release notes (published separately) for further details. +• *AIRBAG +◦ Enhance the robustness of *AIRBAG_INTERACTION to help avoid insta- +bility in MPP when the interaction involves more than two bags. +◦ *AIRBAG_PARTICLE: + Adjust dm_out calculation of vent hole to avoid truncation error. + Fix bug in chamber output when there are multiple airbags and mul- +tiple chambers not in sequential order. + Bug fix for closed volume of airbag/chamber with intersecting tubes. + Add new feature to allow user to define local coordinates of jetting of +particles through internal vents. + Support *SENSOR_CONTROL for CPM airbag. + CPM is not supported for dynamic relaxation. Disable CPM airbag +feature during DR and reactivate airbag following DR. + Allow solid parts in definition of internal part set. The solid volume +will be excluded from the airbag volume. + Allow additional internal part set for shells. The shell part should +form a closed volume and its volume will be excluded from the air- +bag volume. +• *ALE +INTRODUCTION +◦ *LOAD_BLAST_SEGMENT: Automatically generate the ALE ambient el- +ements attached to a segment or segment set. +◦ *BOUNDARY_AMBIENT_EOS: +implement +*DEFINE_CURVE_FUNCTION for the internal energy and relative vol- +ume curves. +◦ *CONTROL_ALE, +*CONSTRAINED_LAGRANGE_IN_SOLID +and +*ALE_REFERENCE_SYSTEM: If NBKT < 0 +in *CONTROL_ALE, call +*DEFINE_CURVE to load a curve defining the number of cycles between +bucket sorting in function of time. If NBKT > 0, the bucket sorting is acti- +vated if the mesh rotations and deformations are large. +◦ *ALE_FSI_TO_LOAD_NODE: Implement a mapping of the FSI accelera- +tions +by +forces/masses) +*CONSTRAINED_LAGRANGE_IN_SOLID (ctype = 4) between different +meshes. +computed +(penalty +◦ DATABASE_FSI, +and +*DATABASE_BINARY_FSILNK: Add a parameter CID to output fsi forces +in a local coordinate system. +◦ Structured ALE (S-ALE) solver: +*DATABASE_BINARY_FSIFOR + ALE models using rectilinear mesh can be directly converted to S- +ALE models and run using S-ALE solver by assigning CPIDX = -1 in +*ALE_STRUCTURED_MESH. + S-ALE +via +*ALE_STRUCTURED_MESH_CONTROL_POINTS. +progressive mesh +generation +RATIO +in +◦ Recode ALE Donor Cell/Van Leer advection routines and restructure +communication algorithm. +*CONSTRAINED_LAGRANGE_IN_SOLID +These give 30% improvement in run time. +• *BOUNDARY +◦ *BOUNDARY_PWP can now accept a *DEFINE_FUNCTION instead of a +load curve. The input arguments are the same as for *LOAD_SEGMENT: +(time, x, y, z, x0, y0, z0). +option +for +of +*BOUNDARY_PRESCRIBED_ORIENTATION_RIGID to offset the curves +by the birth time. +"toffset" +◦ Add +◦ MPP now supports MCOL coupling, *BOUNDARY_MCOL. +◦ Fix bug of there being fully constrained motion of a rigid part when pre- +with +one +in +scribing +translational +*BOUNDARY_PRESCRIBED_MOTION_RIGID while +*MAT_RIGID, i.e., all rotational dof are constrained. +dof +con2 = 7 +more +than +◦ Instead of error terminating with warning message, STR+1371, when +*BOUNDARY_PRESCRIBED_MOTION and *BOUNDARY_SPC is applied +INTRODUCTION +to same node and dof, issue warning message, KEY+1106, and release the +conflicting SPC. +erroneous +SET_BOX +results +option +used +for +is +if +◦ Fix +*BOUNDARY_PRESCRIBED_MOTION. +◦ Fix *BOUNDARY_PRESCRIBED_ACCELEROMETER_RIGID for MPP. It +may error terminate or give wrong results if more than one of this key- +word is used. +◦ Fix +segmentation +using +*BOUNDARY_PRESCRIBED_ORIENTATION with vad = 2, i.e. cubic +spline interpolation. +when +fault +◦ Added instruction *BOUNDARY_ACOUSTIC_IMPEDANCE for explicit +calculations that applies an impedance boundary condition to the bounda- +ry of *MAT_ACOUSTIC element faces. This is a generalization of the non- +and +reflecting +*BOUNDARY_ACOUSTIC_IMPEDANCE may be used on the same faces, +in which case the boundary acts like both and entrant and exit boundary. +◦ Fixed a problem with non-reflecting boundaries redefining the bulk modu- +condition. +boundary +*LOAD +Both +lus which caused contact to change behavior. +◦ Added support for acoustic materials ith non-reflective boundaries. +◦ Fix the single precision version so that *INCLUDE_UNITCELL now has no +problem to identify pairs of nodes in periodic boundaries. +◦ When using *INCLUDE_UNITCELL to generate Periodic Boundary Con- +straints (PBC) for an existing mesh, a new include file with PBCs is gener- +ated instead of changing the original mesh input file. For example, if users +include a file named "mesh.k" through *INCLUDE_UNITCELL (INPT = 0), +a new include file named "uc_mesh.k" is generated where all PBCs are de- +fined automatically following the original model information in mesh.k. +◦ *INCLUDE_UNITCELL now supports long input format in defining the +element IDs. +◦ Include SPC boundary conditions as part of H8TOH20 solid element con- +version. +◦ Add a new option SET_LINE to *BOUNDARY_PRESCRIBED_MOTION: +This option allows a node set to be generated including existing nodes and +new nodes created from h-adaptive mesh refinement along the straight +line connecting two specified nodes to be included in prescribed boundary +conditions. +• BLAST +◦ *PARTICLE_BLAST and DES: + Consider eroding of shell and solid in particle_blast. + Support interface force file output for gas particle-structure coupling. + Bug fix for wet DES coupled with beam. + Support *SET_NODE_GENERAL PART with SPH or DES. +INTRODUCTION + MPP now uses async communication for DES coupling to improve +general performance. + Support for solid element when modeling irregular shaped charge +with HECTYPE = 0/1 in *PARTICLE_BLAST. + Output adaptive generated DES and NODE to a keyword file. +◦ Fix inadvertent detonation of HE part when there are more than one HE +is not defined with +the HE part +though +even +part and +*INITIAL_DETONATION. +explicit +to +explicit +◦ Fixed +*BOUNDARY_USA_COUPLING +support +*INITIAL_STRESS and *INITIAL_STRAIN_ usage, typically from a dynain +file. +◦ Fixed +support +*CONTROL_DYNAMIC_RELAXATION IDRFLF = 5, so a static implicit +calculation can be used to initialize/preload a model before conducting an +explicit transient calculation. If inertia relief is used during the static +phase, +with +*CONTROL_IMPLICIT_INERTIA_RELIEF for the explilcit phase. +*BOUNDARY_USA_COUPLING +disabled +must +then +be +to +it +◦ Support imperial unit system for *PARTICLE_BLAST. mass = lbf-s2/in, +length = inch, time = second, force = lbf, pressure = psi. +◦ Add option +to define detonation point using a node +for +*PARTICLE_BLAST. +◦ Add interface force file output for *PARTICLE_BLAST with keyword +*DATABASE_BINARY_PBMFOR and command line option "pbm=". This +output of forces for gas-particle-structure coupling. +◦ For *PARTICLE_BLAST, add built-in smoothing function for particle struc- +ture interaction. +◦ For *PARTICLE_BLAST, when coupling with DEM, the DEM nodes that +are inside HE domain are automatically deactivated. +◦ Add support for solid elements when modeling irregular shaped charge +with HECTYPE = 0/1 for *PARTICLE_BLAST. The original approach only +supports shell elements and the initial coordinates of HE particle are at +shell surface. The model had to relax several hundred time step to let par- +ticle fill in the interior space, which was not convenient. Using new ap- +proach, the initial positions of HE particles are randomly distributed inside +the container by using solid element geometry. Both hex and Tet solids are +supported. +◦ For particle blast method (PBM), consider reflecting plane as infinite. +◦ Change +the name of keyword *DEFINE_PBLAST_GEOMETRY +to +*DEFINE_PBLAST_HEGEO. +• *CESE (Compressible Fluid Solver) +◦ CESE time steps: +INTRODUCTION + Modified the blast wave boundary condition treatment to make it +(with +calculations +stable +wave +more +blast +*LOAD_BLAST_ENHANCED). +in + The flow field calculation will be skipped if the structural time-step is +much smaller than the fluid time step, until both time-steps reach the +same order. This will save CPU time in some fluid/structure interac- +tion (FSI) problem calculations. + In addition to depending upon the local CFL number, the fluid time +step 'dt' calculation has been modified to also adjust dynamically to +extreme flow conditions. This makes stiff flow problems more stable +especially in 3D fluid problem calculations when the mesh quality is +poor. +◦ Moving mesh solvers: + Corrected several aspects of the implicit ball-vertex (BV) mesh mo- +tion solver for the following keywords: +*ICFD_CONTROL_MESH_MOV +*CESE_CONTROL_MESH_MOV. + The absolute tolerance argument is no longer used by the BV solver. +As an example, the following is all that is needed for CESE moving +mesh problems: +*CESE_CONTROL_MESH_MOV + $ ialg numiter reltol + 1 500 1.0e-4 + Also corrected the CESE moving mesh solvers for a special case in- +volving a wedge element. Also, fixed the d3plot output of wedge el- +ement connectivities for the CESE moving mesh solvers. +◦ CESE d3plot output: + Added real 2D CESE output, and this is confirmed to work with +LSPP4.3 and later versions. This also works for d3plot output with +the 2D CESE axisymmetric solver. + For all immersed-boundary CESE solvers, corrected the plotting of +the Schlieren number and the chemical species mass fractions. + The following new CESE input cards are related to surface d3plot +output: +*CESE_SURFACE_MECHSSID_D3PLOT +*CESE_SURFACE_MECHVARS_D3PLOT +In conjunction with the above, new FSI and conjugate heat transfer +output on solid (volume) mesh outside boundaries is now supported. +◦ CESE immersed-boundary method (IBM) FSI solvers: +INTRODUCTION + *CESE_FSI_EXCLUDE is a new keyword for use with the CESE im- +mersed boundary method FSI solvers. With it, unnecessary structur- +al parts that are not actively participating in the FSI in the CESE IBM- +FSI solver can now be excluded from the CESE FSI calculation. This +is also supported for the case when some of the mechanics parts in- +volve element erosion. +◦ CESE chemistry solvers: + In R10, we also updated several things in the FSI solver with chemis- +try called FSIC. In chemical reacting flow, a delta time between itera- +tions is extremely important for code stabilization and thus, to get +reasonable results. To this end, we optimized such an iterative delta +time, which is based on the CFL number. This optimization is based +on the gradient of the local pressure, which we think will dominate +control of the CFL number. + Next, the total number of species are increased up to 60 species in +chemical reacting flow, so that the reduced Ethylene (24~53 species) +and Methane (20~60 species) combustion are possible with this ver- +sion. + We will update more practical examples about FSIC problems includ- +ing precise experimental validations. + Note that we can provide some related examples upon user request. + Other corrections of note include the following: +Brought in enthalpy-related corrections to the CESE chemistry solv- +ers. +Fixed the conjugate heat transfer boundary condition for the 2D and +3D CESE fixed mesh chemistry solvers. +Corrected the initialization of fluid pressure for CESE IBM chemistry +solvers. +Enabled output of the timing information for the CESE chemistry +solvers. +Added restart capability to the CESE chemistry solvers. +• *CHEMISTRY +◦ New inflator models of Pyrotechnic and Hybrid type are updated. It is +important to note that these are basically 0-dimensional models via the fol- +lowing two main keywords, +*CHEMISTRY CONTROL_INFLATOR +*CHEMISTRY_INFLATOR_PROPERTIES +◦ By using the *CHEMISTRY CONTROL_INFLATOR keyword, the user can +select the type of the solver, output mode, running time, delta t, and time +interval for output of time history data. +For example, if we have a keyword set up as, +INTRODUCTION +*CHEMISTRY CONTROL_INFLATOR, + $ isolver ioutput runtime delt p_time + 1 0 0.1 1.0e-6 5.0e-4 +with "isolver set to 1", the user can simulate a conventional Pyrotechnic in- +flator mode, while with "isolver" set to 2 or 3, Hybrid inflator simulation is +possible. +◦ In addition, to continue an airbag simulation via an ALE or CPM method, +the user can save the corresponding input data file by using "ioutput" op- +tion. For more details about airbag simulations using a saved data file, re- +fer to the keyword manual. +◦ Also, note that the updated version has two options for the Hybrid models: + isolver = 2 => Hybrid model for the cold flow + isolver = 3 => Hybrid model for the heated flow. +◦ In the *CHEMISTRY_INFLATOR_PROPERTIES keyword, there are sever- +al cards to set up the required properties of an inflator model. The first +two cards are for the propellant properties involved in inflator combustion. +For example, + $card1: propellants + $ comp_id p_dia p_height p_mass p_tmass + 10 0.003 0.0013 2.0e-5 5.425e-3 + $card2: control parameters + $ t_flame pindex A0 trise rconst + 2473. 0.4 4.45e-5 0.0 0.037 +In the first card, the user can specify the total amount of propellant parti- +cles and their shape. +Using the second card, the user can also specify the thermodynamics of the +propellant and its burning rate. +To support the options in card2, especially the second option, pindex, and +the third, A0, we provide a standalone program upon request for the pro- +pellant equilibrium simulation. +The remaining cards are for the combustion chamber, gas chamber, and +airbag, respectively. +• *CONTACT +◦ *CONTACT_AUTOMATIC_SURFACE_TO_SURFACE_MORTAR_TIED_ +WELD for modeling welding has been added. Surfaces are tied based on +meeting temperature and proximity criteria. Non-MORTAR version of +this contact was introduced at R9.0.1. +◦ Fix issue setting contact thickness for rigid shells in ERODING contact. +◦ Add MPP support for *CONTACT_AUTOMATIC_GENERAL with adap- +tivity. +INTRODUCTION +◦ Change "Interface Pressure" report in intfor file from abs (force/area) to - +force/area, which gives the proper sign in case of a tied interface in ten- +sion. +◦ Rework input processing so that more than one *CONTACT_INTERIOR +may be used, and there can be multiple part sets in each one. +◦ Minor change to how pressure is computed for triangles in the intfor data- +base. +◦ Fix 2 bugs for contact involving high order shell elements: +- When high order shell elements are generated by SHL4_TO_SHL8. +- When using a large part id like 100000001. +◦ Implement a split-pinball based contact option for neighbor elements in +segment-based contact. Invoke this option by setting |SFNBR|>=1000. +The new algorithm is more compatible with DEPTH = 45 so that there is no +longer a need to split quads. +◦ The effect of shell reference system offsets on contact surface location is +now properly considered when running MPP. The shell offset may be +specified using NLOC in *SECTION_SHELL or in *PART_COMPOSITE, or +by using the OFFSET option of *ELEMENT_SHELL. This effect on contact +is only considered when CNTCO is set to 1 or 2 in *CONTROL_SHELL. +◦ Fix +of +bug +for +*CONTACT_AUTOMATIC_SURFACE_TO_SURFACE after dynamic re- +laxation when consistency is on in SMP. +time = 0.0 +forces +rcforc +zero +in +at +◦ Fix input error when using many *RIGIDWALL_GEOMETRIC_... with +_DISPLAY option. +◦ Fix input error when *CONTACT_ENTITY is attached to a beam part, PID. +◦ Fix error termination due to negative volume, SOL+509, even when +*CONTACT_ERODING... is set. This affects MPP only. +◦ Check whether a slave/master node belongs to a shell before updating the +nodal +*CONTROL_SHELL and +SST/MST.ne.0.0 and in SSFT/SMFT = 0.0 card 3 of *CONTACT_..... For +SMP only. +thickness when +ISTUPD > 0.0 +in +◦ Fix +penetrating +nodes +when +◦ Fix +*CONTACT_ERODING_NODES_TO_SURFACE with +*MAT_142/*MAT_ +seg +using +*CONTACT_AUTOMATIC_SINGLE_SURFACE_TIED with consistency +mode, .i.e. ncpu < 0, for SMP. +when +fault +SOFT = 1 +using +in +◦ Fix +corrupted +intfor when +using +parts/part +sets +in +*CONTACT_AUTOMATIC_....This affects SMP only. +◦ Implement incremental update of normal option, invoked by TIEDID = 1, +for *CONTACT_TIED_NODES_TO_SURFACE_CONSTRAINED_OFFSET +for SMP. +◦ Fix +unconstrained +nodes +when +using +*CONTACT_TIED_SURFACE_TO_SURFACE_CONSTRAINED_OFFSET +resulting in warning message, SOL+540. This affects SMP only. +INTRODUCTION +◦ Fix +spurious +repositioning +of +nodes +when +using +*CONTACT_SURFACE_TO_SURFACE for SMP. +◦ Added support to segment based contact for the SRNDE parameter on op- +tional card E. This option allows round edge extensions that do not extend +beyond shell edges and also square edges. The latter overlaps with the +SHLEDG parameter on card D. +◦ Fixed a potential memory error that could occur during segment based +contact input. +◦ Fixed an error that could cause an MPP job to hang in phase 3. The error +could occur when SOFT = 2 contact is used with the periodic intersection +check and process 0 does not participate in the contact. +◦ Modified SOFT = 2 contact friction when used with *PART_CONTACT to +define friction coefficients, and the two parts in contact have different coef- +ficient values. With this change, the mu values used for contact will be the +average of the values that are calculated for each part. Prior to this change, +mu was calculated for only the part that is judged to be the master. This +change makes the behavior more predictable and also makes it behave like +the other contacts with SOFT = 0 and SOFT = 1. +◦ Fixed +◦ Added a warning message (STR+1392) for when trying to use the OR- +THO_FRICTION contact option with SOFT = 2 contact, because that option +is not available. The contact type is switched to SOFT = 1. +in +MPP +*CONTACT_2D_AUTOMATIC_SURFACE_TO_SURFACE when used +with node sets to define the contact surfaces. The master side was likely to +trigger a spurious error about missing nodes that terminated the job. +serious +error +file +not +force +could +support NFAIL = 1 +◦ Switched segment based (SOFT = 2) non-eroding contact to prevent it from +adding any new segments when brick element faces are exposed when +other elements are deleted. There were two problems. The first is that the +interface +on +*DATABASE_EXTENT_INTFOR because the intfor file does not expect +new segments to replace the old, so it just undeletes the old segments in- +stead of adding the new. The second problem is that when non-eroding +contact is used, we only have enough memory in fixed length arrays for +the segments that exist at t = 0. When segments are deleted, I was using +the space that they vacated to create new segments, but it was very likely +that some segments could not be created when the number of open spaces +was less than the number of new segments that are needed. In this case, +some segments would not be created and there would be surfaces that +could be penetrated with no resistance. This behavior is impossible to +predict, so it seems better to prevent any new segments from being created +unless eroding contact is used. +◦ Fixed rcforc output for MPP 2D automatic contact. The forces across pro- +cessors were missed. +INTRODUCTION +◦ Fixed a segment based contact error in checking airbag segments. This af- +fects only airbags that are defined by control volumes, that is defined by +*AIRBAG. The symptom was a segmentation fault. +◦ Fixed SMP eroding segment based (SOFT = 2) contact which was not acti- +vating the negative volume checking of brick elements. The MPP contact +and the other SMP contacts were doing this but not SMP SOFT = 2. +◦ Fixed support for CNTCO on *CONTROL_SHELL by segment based +(SOFT = 2) contact. It was adjusting the contact surface only half of what it +should have done. +◦ Fixed eroding segment based contact when used with the CNTCO > 0 on +*CONTROL_CONTACT. A segmentation fault was occurring. +◦ Modified MPP segment based (soft = 2) contact to use R8 buffers to pass +nodal coordinates. This should reduce MPP scatter when decomposition +changes. +◦ Added support for using a box to limit the contact segments to those ini- +tially in the box when using eroding segment based contact. The box op- +tion has not been available for any eroding contact up until now. +(SOFT = 2 and SBOXID, MBOXID on *CONTACT_ERODING_...). +◦ Fixed force transducers with MPP segment based contact when segments +are involved with multiple, 2-surface force transducers. The symptom was +that some forces were missed for contact between segments on different +partitions. +◦ Added support for *ELEMENT_SOURCE_SINK used with segment based +contact. With this update, inactive elements are no longer checked for con- +tact. +◦ Fixed an MPP problem in segment based contact that cased a divide by ze- +ro during the bucket sort. During an iteration of the bucket sort, all active +segments were somehow in one plane which was far from the origin such +that a dimension rounded to zero. The fix for this should affect only this +rare case and have no effect on most models. +◦ Modified segment based (SOFT = 2) contact to make SMP and hybrid fast- +er, particularly for larger numbers of processors. +◦ Fixed thermal MPP segment based contact. The message passing of ther- +mal energy due to friction was being skipped unless peak force data was +written to the intfor file. +◦ Fixed likely memory errors in MPP problems with 2D automatic contact +when friction is used. +◦ Support the VC parameter (coefficient for viscous friction) in the case of +segment based contact, which has previously been unsupported. This op- +tion will work best with FNLSCL > 0, DNLSCL = 0 on optional card D. +The card D option causes the contact force to be proportional to the over- +lap area which causes even pressure distribution. +◦ Enabled segment based contact (SMP and MPP) to work with type 24 (27- +node) brick elements. +INTRODUCTION +◦ Fixed MPP segment based contact for implicit solutions. During a line +search, some data was not restored correctly when the solver goes back to +the last converged state. This caused possible memory errors. +◦ Fixed friction for MPP segment based contact in the implicit solver. The +sliding velocity was calculated incorrectly using the explicit time step ra- +ther than the implicit step. +◦ Fixed a bug in MPP *CONTACT_2D_AUTOMATIC..., where a flaw in +code used during MPP initialization could cause segments to fail to detect +penetration. +◦ Fixed +the +of +*CONTACT_2D_AUTOMATIC_SINGLE_SURFACE in the MPP version. +There was a memory error that could occur if thick beams were in the +model. +checking +beam +thick +◦ New +values +history +(*USER_INTERFACE_FRICTION): material directions, relative velocity +components and yield stress. +element +friction +user +for +◦ Add new user-defined +interface for tiebreak contact +invoked by +*CONTACT_AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE_TIEB +REAK_USER. +◦ MORTAR CONTACT + PENMAX and SLDTHK has taken over the meanings of SST and +TKSLS in R9 and earlier, although in a different way. Now PENMAX +corresponds to the maximum penetration depth for solid elements (if +nonzero, otherwise it is a characteristic length). SLDTHK is used to +offset the contact surface from the physical surface of the solid ele- +ment, instead of playing with SST and TKSLS, which was rather +awkward. This update also saves the pain of having to treat shells +and solids in separate interfaces if these features are wanted. This +changes the behavior in some inputs that did have SST turned on for +solids, but a necessary measure to make the contact decent for future +versions. + The characteristic length for solid elements has been revised to not +result in too small sizes that would lead to high contact stiffnesses +and less margin for maximum penetration. + SFS on CONTACT_..._MORTAR can be input as negative, then con- +tact pressure is the -SFS load curve value vs penetration. + Smooth roundoffs of sharp edges in MORTAR contact has been ex- +tended to high order segments, meaning that edge contact is valid +even in this case. + The MORTAR contact now honors the NLOC parameter for shells, +see *SECTION_SHELL, adjusting the contact geometry accordingly. +Note that CNTCO on *CONTROL_SHELL applies as if always active, +meaning that if NLOC is on, then CNTCO will also be "on" for MOR- +TAR contacts. +INTRODUCTION + Output of contact gaps to the intfor file is now supported for MOR- +TAR contact, see *DATABASE_EXTENT_INTFOR. + Transducer contacts, *CONTACT_..._FORCE_TRANSDUCER, are +supported for MORTAR contact in SMP and MPP. A disclaimer is +that the slave and master sets in the transducer have to be defined +through parts or part sets. Warnings are issued if this is violated. + Option 2 +is now supported for +tiebreak MORTAR contact, +*CONTACT_..._MORTAR_TIEBREAK, but only for small sliding. +Options 4 and 7 are supported in the MORTAR tiebreak contact for +any type of sliding. + For explicit analysis, the bucket sort frequency for MORTAR contact +is 100, but can be changed through parameter BSORT on the CON- +TACT_..._MORTAR card or NSBCS on CONTROL_CONTACT. Note +that the MPP bucket sort parameter does not apply. This assumes to +improve the efficiency of MORTAR explicit contact significantly +compared to R9 and earlier versions. + Dynamic friction is supported in MORTAR contact for explicit and +implicit dynamic analysis. See FD and DC on *CONTACT_... card. + Wear calculations are supported for the MORTAR contact. See +CONTACT_ADD_WEAR. + Triangular shell form 24 is supported with MORTAR forming contact +and accounts for high order shape functions. + Automatic MORTAR contact now supports contact with end faces of +beam elements and not just the lateral surfaces. + Mortar contact is available in 2D plane strain and axisymmetric simu- +lations, but only for SMP implicit. See CONTACT_2D_...MORTAR. +◦ Wear computed from *CONTACT_ADD_WEAR can optionally be output +to dynain on optional card of *INTERFACE_SPRINGBACK_LSDYNA. +This will generate *INITIAL_CONTACT_WEAR cards for subsequent +wear simulations, and LS-DYNA will apply this wear and modify geome- +try accordingly. Restrictions as described in the manual apply. +◦ Improve +under +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE to allow +users to define part ID and a node set is automatically generated. +SOFT = 6 +• *CONSTRAINED +◦ Add frictional energy calculation for constraint-based rigid walls. +◦ *CONSTRAINED_BEAM_IN_SOLID: + Works with r-adaptivity now. + Can now constrain beams in tshells as well as solids. +INTRODUCTION +◦ Fix a bug for *CONSTRAINED_LOCAL that might mistakenly constrain z- +translation when RC = 0. +◦ The following options do not support MEMORY = auto properly. The +MEMORY = auto option will be turned off in this section and report an er- +ror if additional memory allocation is needed. +*CONSTRAINED_LINEAR_OPTION +*CONSTRAINED_MULTIPLE_GLOBAL +◦ Switched translational joints with stiffness to use double precision storage +for the displacement value so that the calculated forces are more accurate. +This prevents round-off error that can become significant. +◦ Fixed *CONSTRAINED TIED_NODES_FAILURE when used with MPP +single surface segment based contact. Non-physical contact between seg- +ments that share tied constraints was being penalized leading to failure of +the constraints. +◦ The +SPR +(*CONSTRAINED_SPR2, +*CONSTRAINED_INTERPOLATION_SPOTWELD) now +the +SPOTDEL option of *CONTROL_CONTACT. That means if shell elements +involved in the SPR domain fail, the SPR gets deactivated. +support +models +• *CONTROL +◦ Fix possible error +◦ Fix spurious deletion of elements when using TSMIN.ne.0.0 +termination with single precision MPP when +PSFAIL.ne.0 in *CONTROL_SOLID and using solid formulation 10/13/44. +in +*CONTROL_TERMINATION, erode = 1 in *CONTROL_TIMESTEP and +initialized implicitly in dynamic relaxation. +◦ Added keyword *CONTROL_ACOUSTIC to calculate the nodal motions +of *MAT_ACOUSTIC nodes for use in d3plot and time history files. With- +out this option the *MAT_ACOUSTIC mesh propagates pressure but does +not deform because it uses a linear Eulerian solution method. The struc- +tural response is unaffected by this calculation; it is only for visualization +and will roughly double the time spent computing acoustic element re- +sponse. +◦ When IACC = 1 on *CONTROL_ACCURACY and for shell type 16/-16 in +nonlinear implicit, shell thickness change due to membrane strain when +ISTUPD > 0 in *CONTROL_SHELL is now included in the solution process +and will render continuity in forces between implicit time steps. The out- +put contact forces will reflect the equilibrated state rather than the state +prior or after the thickness update. +is used +◦ Fix bug when RBSMS in *CONTROL_RIGID, affecting mass scaled solu- +in conjunction with *ELEMENT_INERTIA and/or +on +and +tions, +*PART_INERTIA, +*CONSTRAINED_RIGID_BODIES +*CONSTRAINED_EXTRA_NODES. +specifically with +choices +IFLAG +of +◦ Tshells added to the subcycling scheme (*CONTROL_SUBCYCLE). +INTRODUCTION +◦ Tshells and spotweld beams are supported in selective mass scaling. See +IMSCL in *CONTROL_TIMESTEP. +◦ Add a new keyword: *CONTROL_FORMING_SHELL_TO_TSHELL to +convert shell elements to tshell elements. + If a parent node has SPCs, the same SPC constraints will be applied to +the corresponding tshell nodes. + If adaptivity is invoked, *BOUNDARY_SPC_SET is automatically +updated to include newly generated nodes. + Allows the normal of the segment set to be changed. + Can offset the generated tshells from the mid-surface of the parent +shells. + Automatically generate segment sets for the top and bottom surfaces, +which can be used for contact. +• DISCRETE ELEMENT METHOD +◦ Implement +generalized +for +*DEFINE_DE_TO_SURFACE_COUPLING based on the following article +in the journal "Wear": Magnee, A., Generalized law of erosion: application +to various alloys and intermetallics, Wear, Vol. 181, 500, 1995. +erosion +law +of +◦ Modify tangential force calculation to get better rigid body rotation behav- +ior for *DEFINE_DE_BOND +◦ Support restart feature for DEM interface force file and DATABASE out- +put. +◦ Instead of using bulk modulus, use mass and time step to estimate contact +stiffness for SPH-DEM coupling. This should be better if DEM material is +quite different from SPH material. +◦ Fix *DEFINE_DE_MASSFLOW_PLANE bug if DE injection is defined. +◦ Add CID_RCF to *DEFINE_DE_TO_SURFACE_COUPLING for force out- +put in local coordinates to 'demrcf' file. +◦ Update the *DEFINE_DE_BY_PART card so that it matches the capabilities +of the *CONTROL_DISCRETE_ELEMENT card. +◦ Add penalty stiffness scale factor, thickness scale factor, birth time and +death time to *DEFINE_DE_TO_SURFACE_COUPLING. +◦ Add dynamic coefficient of friction to *CONTROL_DISCRETE_ELEMENT. +to +◦ Implement Finnie's wear +law and user defined wear model +*DEFINE_DE_TO_SURFACE_COUPLING. +◦ Implement user-defined curve for DEM frictional coefficient as function of +time. +◦ Implement user-defined curve +for contact +force calculation +for +*CONTROL_DISCRETE_ELEMENT. +◦ Fix +inconsistent +results +between +*DEFINE_DE_BY_PART +and +*CONTROL_DISCRETE_ELEMENT. +INTRODUCTION +• *ELEMENT +◦ Fixed bug affecting output from beam elements ELFORM = 2 when certain +uncommon inputs are present. Forces and moments in the output files +could be wrongly rotated about the beam axis. This affected the output +files only, not the solution inside LS-DYNA. The error could occur under +two circumstances: (a) if IST on *SECTION_BEAM is non-zero, the output +forces and moments are supposed to be rotated into the beam's principal +axis system, but this rotation could be applied to the wrong beam ele- +ments; and (b) when no ELFORM = 2 elements have IST, but the model al- +the +so contains beams with ELFORM = 6 and RRCON = 1 on +SECTION_BEAM card, some of the ELFORM = 2 elements can have their +output forces and moments rotated by 1 radian. +◦ Fix a bug affecting 2d seatbelt with time-dependent slipring friction. +◦ Fix erroneous 1d seatbelt slipring message. +◦ Fix seatbelt consistency issue in SMP (ncpu < 0). +◦ Add error message when 2d seatbelt part doesn't have shell formulation of +5 and *MAT_SEATBELT. +◦ Fix a bug for 2d seatbelt that could occur when a model has both 1d and 2d +belts, and a 1d pretensioner of type 2, 3 or 9. +◦ Fix an MPP seatbelt bug that could occur when using a type 9 pretension- +er. +◦ Allows shell formulation 9 to be used for 2d seatbelt. It was reset to formu- +lation 5 by LS-DYNA, no matter what formulation was input. Now, only +formulation 5 and 9 are accepted as input. Other formulations will incur +error message. +◦ MPP now supports *ELEMENT_MASS_MATRIX_NODE_(SET). +◦ Added cohesive shell formulation -29. This formulation uses a cohesive +midlayer where local direction q1 coincides with the average of the sur- +rounding shell normals. This formulation is better suited for simulating +normal shear. +◦ Cohesive shell formulation +/-29: Fixed absence of part mass in d3hsp. +◦ Make *TERMINATION_DELETED_SOLIDS work with hex spot weld fail- +ures. +◦ Fix incorrect load curve used if large value is used for FC < 0 and/or +FCS < 0 in *ELEMENT_SEATBELT_SLIPRING. +◦ Fix incorrect velocity on accelerometer if + velocity is prescribed on the rigid body that the accelerometer is at- +tached to, and + INTOPT = 1 in *ELEMENT_SEATBELT_ACCELEROMETER, and + *INITIAL_VELOCITY_GENERATION_START_TIME is used. +◦ Fix incorrect discrete spring behavior when used with adaptivity. +INTRODUCTION +◦ Fix input error when using *DEFINE_ELEMENT_DEATH with BOXID > 0 +for MPP. +◦ Modify tolerances on error messages SOL+865 and SOL+866 to prevent +unnecessary error terminations when translational or rotational mass of a +discrete beam was close to zero. +◦ Made the solid element negative volume warning SOL+630 for penta for- +mulatgion 15 consistent with the volume calculation in the element. With +this change, elements are deleted rather than the job terminating with error +SOL+509. +◦ Fixed the default hourglass control for shell form 16. It was defaulting to +type 5 hourglass control rather than 8. +◦ Fixed default hourglass control when the *HOURGLASS control card is +used but no HG type is specified. We were setting to type 1 instead of 2. +Also, fixed the default HG types to match the user's manual for implicit +and explicit. +◦ Fixed the fully integrated membrane element (shell ELFORM = 9) when +used with NFAIL4 = 1 on *CONTROL_SHELL and there are triangular el- +ements in the mesh. Triangular elements were being deleted by the dis- +torted element check. +◦ Fixed a divide by zero error that occurred with *SECTION_BEAM, +-12, and node 3 was omitted on +ELFORM = 6, SCOOR = 12 or +*ELEMENT_BEAM, and nodes 1 and 2 are along the global y-direction or +z-direction. +◦ Fixed laminated shell theory for type 6 and 7 shell elements when made +active by LAMSHT = 3 or 5 on *CONTROL_SHELL. +◦ Added an +int.pt. + variable +for *PART_COMPOSITE_LONG and +*PART_COMPOSITE_TSHELL_LONG called SHRFAC which is a scale +factor for the out-of-plane shear stress that allows the user to choose the +stress distribution through thickness. This was motivated by test data that +shows that for large differences is layer shear stiffness, the parabolic as- +sumption is poor. +◦ Fixed implicit hourglass stiffness in viscoelastic materials when used with +tshell forms 5 or 6. The stiffness was much too small. +◦ Modified tshell type 5 to use the tangent stiffness for calculating the Pois- +son's affects and hourglass control for *MAT_024. This makes the behavior +softer during buckling which is much more realistic. +◦ Fixed a significant bug in segment based contact when SHLEDG = 1 and +SBOPT = 3 or 5 and DEPTH < 45, and shell segments in contact have dif- +ferent thicknesses. A penetration check was using incorrect thicknesses +causing contact to be detected too late, particularly for edge to surface con- +tact. +◦ Improved the time step calculation for triangular tshell elements. The time +step was too conservative for elements with significant thickness. This fix +does not affect tshell type 7. +INTRODUCTION +◦ Fixed all tshells to work with anisotropic thermal strains which can be de- +fined by *MAT_ADD_THERMAL. Also, this now works by layer for lay- +ered composites. +◦ Enabled tshell form 5 to recalculate shear stiffness scale factors when plas- +ticity material models 3, 18, 24, 123, or 165 are included in a composite sec- +tion. Prior to this change the scale factors were based on elastic properties +so after yielding, the stress distribution was not what was expected. This +new capability supports the constant stress option, the parabolic option, +and the SHRFAC option on *PART_COMPOSITE_TSHELL_LONG. +◦ Improved tshell 5 when used with mixed materials in the layers. A failure +to use the correct Poisson's ratio was causing a less accurate stress tensor. +◦ Modified the time step calculation for tshell forms 3 and 5. A dependence +on volumetric strain rate was removed in order to prevent oscillations in +the time step which caused stability problems, particularly for tshell 5. +(TSHEAR = 1 +on +*SECTION_TSELL or *PART_COMPOSITE). It was producing a not very +constant stress distribution. +constant +◦ Fixed +option +stress +tshell +shear +◦ Fixed stress and strain output of tshells when the composite material flag +CMPFLG is set on *DATABASE_EXTENT_BINARY. The transformation +was backwards. +mass +when +*ELEMENT_SHELL_SOURCE_SINK is used. The mass of inactive ele- +ments was being included. +reported +◦ Fixed +d3hsp +parts +of +to +◦ Enabled *MAT_026 and *MAT_126 (HONEYCOMB) to be used with tshell +forms 3, 5, and 7. It was initialized incorrectly causing a zero stress. +◦ Added a missing internal energy calculation for tshell form 6. +◦ Enabled tshell forms 1, 2, and 6 to work with material types 54, 55, and 56. +◦ Modified the z-strain distribution in tshell forms 5 and 6 when used in +composites with mixed materials that are isotropic. The existing assumed +strain scheme was doing a poor job of creating a constant z-stress through +the thickness. +◦ Increased the explicit solution time step for thin shell composite elements. +The existing method calculated a sound speed using the stiffness from the +stiffest layer and dividing it by the average density of all layers. This could +be overly conservative for composites with soft layers of low density. The +new method uses the average stiffness divided by average density. This is +still conservative, but less so. +◦ Corrected rotational inertia of thin shells when layers have mixed density +and the outer layers are denser than inner layers. The fix will mostly affect +elements that are very thick relative to edge length. +◦ Added support for *ELEMENT_SHELL_SOURCE_SINK to type 2 shells +with BWC = 1 on *CONTROL_SHELL. +◦ Prevent +(from +shell +*ELEMENT_SHELL_SOURCE_SINK) from controlling the solution time +step. +elements +inactive +INTRODUCTION +◦ Fixed *LOAD_STEADY_STATE_ROLLING when used with shell form 2 +(BWC = 1 +Belytschko- Wong-Chang warping +and +*CONTROL_SHELL). The load was not being applied. +stiffness +◦ Improved the brick element volume calculation that is used by the option +erode elements (ERODE = 1 on *CONTROL_TIMESTEP or PSFAIL.ne.0 on +*CONTROL_SOLID). It was not consistent with the element calculation +which caused an error termination. +◦ Fixed all tshell forms to work with anisotropic thermal strains which can +be defined by *MAT_ADD_THERMAL. Also, this now works by layer for +layered composites. +◦ Reworked shell output so that we can correctly output stress in triangular +shells when triangle sorting is active, that is when ESORT = 1 or 2 on +*CONTROL_SHELL. +◦ *ELEMENT_T/SHELL_COMPOSITE(_LONG) +and +*PART_COMPOSITE_T/SHELL_(LONG): Permit the definition of zero +thickness layers in the stacking sequence. This allows the number of inte- +gration points to remain constant even as the number of physical plies var- +integration point +ies and eases post-processing since a particular +corresponds to a physical ply. Such a capability is important when plies +are not continuous across a composite structure. +To represent a missing ply, set THK to 0.0 for the corresponding integra- +tion point and additionally, either set MID = -1 or set PLYID to any non- +zero value. Obviously, the PLYID option applies only to the keywords +containing LONG. +◦ Implemented sum factorization for 27-node quadratic solid that may in- +crease speed by a factor of 2 or 3. +◦ Support second order solid elements (formulations 23,24,25,26) for +*SET_NODE_GENERAL. +◦ Invoke consistent mass matrix of 27-node hex element for implicit dynam- +ics and eigenvalues. +◦ Reorder node numbering when assembling global stiffness matrix for 27- +node hex. This fixes a bug in which it was reported than the implicit 27- +node element didn't work +◦ Automatically transfer nodal boundary conditions for newly generated +nodes if H8TOH27 option is used in *ELEMENT_SOLID. +◦ Modify initialization of material directions for solid elements. If there are +only zeros for all the 6 values in *INITIAL_STRESS_SOLID, then the values +from the other input (e.g. *ELEMENT_SOLID_ORTHO) are kept. +◦ Enable *PART_STACKED_ELEMENTS to pile up shell element layers. Be- +fore, it was necessary that solid element layers were placed between shell +element layers. Now, shell element layers can follow each other directly. +Contact definitions have to be done separately. +◦ Allow *PART_STACKED_ELEMENTS to be used in adaptive refinement +simulations. +INTRODUCTION +◦ Add alternative mass calculation for critical time step estimate of cohesive +elements. This hopefully resolves rarely occurring instability issues. Op- +tion ICOH on *CONTROL_SOLID is used for that. +◦ Correct the strain calculation for tet formulation 13. This did not affect the +stress response, only output of strains. Nodal averaging was not account- +ed for. +◦ User +defined +*SECTION_SHELL/SOLID) +*MAT_ADD_EROSION. +elements +(ELFORM = 101 +can +now +be used +to +105 +on +together with +◦ Add option +to define a pull-out +in +*ELEMENT_BEAM_SOURCE by defining a negative variable FPULL. +|FPULL| +or +refer +*DEFINE_CURVE_FUNCTION. +*DEFINE_CURVE +time curve +force vs. +can +to +◦ Solid tet form 13 supported for all materials in implicit, including a pre- +sumable consistency improvement for the future. +◦ The Hughes-Liu beam is supported in *INTEGRATION_BEAM such each +integration point may refer to a different part ID and thus have a different +coef. Of thermal expansion. See *MAT_ADD_THERMAL_EXPANSION. +◦ Shell types 2 and 16 that combines thermal expansion and thick thermal +shells, see *MAT_ADD_THERMAL_EXPANSION and TSHELL on +*CONTROL_SHELL, now correctly treat temperature gradient through the +thickness to create bending moments. All shell types are to be supported +in due time. +◦ *SECTION_BEAM_AISC now provides predefined length conversion fac- +tors for specific unit systems. +◦ 3D tet r-adaptivity now supports *DEFINE_BOX_ADAPTIVE. + For every adaptive part, users can define multiple boxes where dif- +ferent BRMIN & BRMAX (corresponding to RMIN & RMAX in +*CONTROL_REMESHING) can be specified for 3D tet remesher to +adjust the mesh size. + Current implementation does not support LOCAL option. +◦ Fix bug in 3D adaptivity so that users can now have both non-adaptive +tshell parts and 3D adaptive parts in one analysis. +◦ Fix the bug in 3D adaptivity so that users can now have both dummy +nodes and 3D adaptive parts in one analysis. +• *EM (Electromagnetic Solver) +◦ Randles Circuits for Battery Modeling + A Randles circuit is an equivalent electrical circuit that consists of an +active electrolyte resistance r0 in series with the parallel combination +of the capacitance c10 and an impedance r10. The idea of the distrib- +INTRODUCTION +uted Randles model is to use a certain number of Randles circuits be- +tween corresponding nodes on the two current collectors of a battery +unit cell. These Randles circuits model the electrochemistry that +happens in the electrodes and separator between the current collec- +tors. The EM solver can then solve for the EM fields in the current +collectors, and the connections between them. + Added analysis of distributed Randles circuits to MPP. + Added d3plot output for distributed Randles circuits: + D3PL_RAND_r0_EM, + D3PL_RAND_r10_EM, + D3PL_RAND_c10_EM, + D3PL_RAND_soc_EM, + D3PL_RAND_i_EM, + D3PL_RAND_u_EM, + D3PL_RAND_v_EM, + D3PL_RAND_vc_EM, + D3PL_RAND_temperature_EM, + D3PL_RAND_P_JHR_EM, + D3PL_RAND_P_dudt_EM, + D3PL_RAND_i_vector_EM +This output can be visualized in LS-PrePost versions 4.3 and 4.5 on +the +using +Post/FriComp/Extend/EM node. +separator +battery +part +cell +the +of + Added tshells for EM analysis for use in battery modeling. + Added new capability for modeling Randles short, based on +*DEFINE_FUNCTION so that the user has a lot of freedom to define +where and when the short happens as well as the short resistance. + Added a new capability for battery exothermal reactions also based +on +keyword +*RANDLE_EXOTHERMAL_REACTION makes it possible to com- +plement the heating of a short circuit created by a short by exother- +mal reactions if, for example, the temperature becomes higher than a +threshold value. +*DEFINE_FUNCTION. +new +The +• FORMING ANALYSIS +◦ Extend *INCLUDE_AUTO_OFFSET to solid and beam elements (draw +beads). +◦ Add +a +for +new +keyword +compensa- +tion:*INTERFACE_COMPENSATION_NEW_REFINE_RIGID to refine and +break rigid tool mesh along the user supplied trim curves so compensated +tool mesh follows exactly the blank mesh (file "disp.tmp"). This needs to +be done only once in the beginning of the springback compensation (IT- +ER0). +springback +◦ *CONTROL_FORMING_ONESTEP: +INTRODUCTION + Change the default element formulation option for onestep method +to QUAD2. + Add a new option QUAD to allow quadrilateral elements to be con- +sidered. + Limit the maximum thickening by using a new variable TSCLMAX +for the sheet blank. + Set the value of OPTION to a negative value to output the file 'on- +estepresult' in large format (E20.0). + Calculate and add the damage factor and output to the 6th history +variable in the output file "onestepresult". Add the variable for a +curve ID to define the fracture strain vs. triaxility. Add another vari- +able DMGEXP (damage parameter), as used in GISSMO model. + Keep the original coordinates for the onestep output "onestepresults". +◦ Add a new option VECTOR to *CONTROL_FORMING_BESTFIT to output +deviation vector (in the format of: NODEID, xdelta, ydelta, zdelta) for each +node to its closest target element. The deviation vectors are output under +the keyword *NODE_TO_TARGET_VECTOR. +◦ *CONTROL_FORMING_OUTPUT: + Output will skip any negative abscissa (Y1) value. + When CIDT < 0, the positive value defines the time dependent load +curve. +◦ Add +a +warning +compensation +*INTERFACE_SPRINGBACK_COMPENSATION to identify which input +file (typically the blank with adaptive mesh not output directly by LS- +DYNA) has the wrong adaptive constraints. +springback +in +◦ *INTERFACE_COMPENSATION_3D: turn off the output of nikin file. +◦ *ELEMENT_LANCING: + Allow some unused lancing curves to be included in the input. + When the gap between the two ends of a lancing curve is not zero, +but small enough, then this curve is automatically closed. + Allow several parts to be cut during lancing; the parts can be +grouped in *SET_PART_LIST, and defined using a negative value +IDPT. + Specify the distance to bottom dead center as AT and ENDT when +the new variable CIVD is defined. + Set IREFINE = 1 (default) in lancing, to refine blank mesh automati- +cally along the lancing curves. + Re-set the adaptive level to be 1 to prevent those elements along the +lancing route to be further refined. +INTRODUCTION + When IREFINE = 1, elements along the lancing curve will be refined +to make sure that no adapted nodes exist in the neighborhood. This +helps get improved lancing boundary. + Change of tolerance for lancing to merge the small elements into big- +ger ones. +◦ Add a new keyword to perform trimming after lancing (shell elements on- +ly): *DEFINE_LANCE_SEED_POINT_COORDINATES. Maximum of two +seed nodes can be defined. +◦ Extend *CONTROL_FORMING_TOLERANC to *MAT_036, *MAT_037, +*MAT_125, and *MAT_226. When beta is less than -0.5, there is no necking +and no calculation of FI. When beta is greater than 1.0, beta = 1.0/beta. +This keyword adds a smoothing method to calculate the strain ratios for a +better formability index. +◦ Sandwiched parts (*CONTROL_ADAPTIVE, *DEFINE_CURVE_TRIM): + Disable *CONTROL_ADAPTIVE_CURVEs for sandwich parts, since +refinement along the curve is automatically done during trimming. + Refine the elements along the trimming curve to make sure no slave +nodes are be cut by trimming curves. + Allow mesh adaptivity. + Allow multi-layers of solids. + Add a check to the variable IFSAND in *CONTROL_ADAPTIVE for +sandwich part to be refined to exclude solid elements. +◦ Solid element trimming (*DEFINE_CURVE_TRIM): + Refine those elements along the trimming curve. + Improve solid trimmig to allow the trimming of one panel into two +panels with two seed nodes. +◦ Add +a +keyword +*CONTROL_FORMING_REMOVE_ADAPTIVE_CONSTRAINTS +re- +move adaptive constraints on a formed, adapted blank, and replaced them +with triangular elements. +new +to +◦ *DEFINE_CURVE_TRIM_NEW: Allow trimming of tshells. +◦ Add a new keyword:*INTERFACE_WELDLINE_DEVELOPMENT to ob- +tain initial weld line from the final part and the final weld line position. + When Ioption = -1, convert weld line from its initial position to the fi- +nal part. + Output the element nodes that intersect the weld line in the final part, +and the output file is: affectednd_f.ibo + Output the element nodes that intersect the weld line in the initial +part, and the output file is: affectednd_i.ibo +INTRODUCTION +◦ Add a new variable DT0 to *CONTROL_IMPLICIT_FORMING so there is +no need to use *CONTROL_IMPLICIT_GENERAL to specify DT0. +◦ *INTERFACE_BLANKSIZE: + Add a new feature DEVELOPMENT option. When ORIENT = 2, +then a reference mesh file for the formed part should be included. +The calculated and compensated boundary will be based on the ref- +erence mesh. + Add a new option SCALE_FACTOR that allows the target curve to be +moved. This is useful when multiple target curves (e.g. holes) and +formed curves are far away from each other. +• *FREQUENCY_DOMAIN +◦ Added new keyword *CONTROL_FREQUENCY_DOMAIN to define +global control parameters for frequency domain analysis. Currently two +parameters are defined: + REFGEO: flag for reference geometry in acoustic eigenvalue analysis +(either the original geometry at t = 0, or the deformed geometry at the +end of transient analysis). + MPN: large mass added per node, to be used in large mass method +for enforced motion. +◦ *FREQUENCY_DOMAIN_ACOUSTIC_BEM: + Enabled +wave +(*FREQUENCY_DOMAIN_ACOUSTIC_INCIDENT_WAVE) in Ray- +leigh method (METHOD = 0). +incident +using + Enabled +plot +(*FREQUENCY_DOMAIN_ACOUSTIC_FRINGE_PLOT) in Rayleigh +method (METHOD = 0). +pressure +acoustic +fringe + Fixed bug in running acoustic analysis with multiple boundary con- +ditions in MPP. + Fixed running MATV (Modal Acoustic Transfer Vector) approach in +MPP (*FREQUENCY_DOMAIN_ACOUSTIC_BEM_MATV). + Added treatment for triangular elements used in Rayleigh method +(METHOD = 0). + Added output of acoustic intensity to binary database D3ACS (de- +fined by *DATABASE_FREQUENCY_BINARY_D3ACS). + Fixed bug in acoustic pressure fringe plot for collocation BEM +(METHOD = 3) and dual BEM based on Burton-Miller formulation +(METHOD = 4). +◦ *FREQUENCY_DOMAIN_ACOUSTIC_FEM: +INTRODUCTION + Fixed bug in acoustic analysis by FEM, when dimensions of mass and +k (stiffness) matrices are mismatched. +◦ *FREQUENCY_DOMAIN_ACOUSTIC_FRINGE_PLOT: + Implemented acoustic fringe plot for MPP for the options PART, +PART_SET, and NODE_SET. +◦ *FREQUENCY_DOMAIN_FRF: + Added new loading types: +VAD1 = 5: enforced velocity by large mass method + = 6: enforced acceleration by large mass method + = 7: enforced displacement by large mass method + = 8: torque + = 9: base angular velocity + = 10: base angular acceleration + = 11: base angular displacement + Added rotational dof output for FRF. +◦ *FREQUENCY_DOMAIN_MODE: + Added option _EXCLUDE to exclude some eigenmodes in modal su- +perposition in frequency domain analysis. +◦ *FREQUENCY_DOMAIN_RANDOM_VIBRATION: + Fixed bug in running random vibration with random pressure wave +load (VAFLAG = 2) in MPP. + Improved random vibration analysis by allowing using complex var- +iable cross PSD functions. Previously cross PSD was defined as real +variables thus the phase difference was ignored. + Added PSD and RMS computation for Von Mises stress in beam ele- +ments. +◦ *FREQUENCY_DOMAIN_RESPONSE_SPECTRUM: + Added Von Mises stress output for beam elements in database +D3SPCM. + Corrected computation of response spectrum at an intermediate +damping value by interpolating spectra at two adjacent damping +values. Now the algorithm is based on ASCE 4-98 standard. +◦ *FREQUENCY_DOMAIN_SSD: + Added new loading types: +VAD = 5: enforced velocity by large mass method +INTRODUCTION + = 6: enforced acceleration by large mass method + = 7: enforced displacement by large mass method + = 8: torque + Fix +for +running SSD +fatigue +in MPP +(affected keyword: +*FREQUENCY_DOMAIN_SSD_FATIGUE). + Updated ssd computation with local damping, and enabled the re- +start feature by reading damping matrix. + Implemented ERP +(Equivalent Radiated Power, +keyword +*FREQUENCY_DOMAIN_SSD_ERP) for MPP. +◦ *DATABASE_FREQUENCY_ASCII: + Added keyword *DATABASE_FREQUENCY_ASCII_{OPTION} to +define the frequency range for writing frequency domain ASCII da- +and +tabases NODOUT_SSD, +ELOUT_PSD. +ELOUT_SSD, NODOUT_PSD +• *ICFD (Incompressible Fluid Solver) +◦ New ICFD features and major modifications + Simple restart is now supported for ICFD. + Added +damping +wave +capabilities. +See +*ICFD_DEFINE_WAVE_DAMPING. + Added steady state solver. See *ICFD_CONTROL_GENERAL and +*ICFD_CONTROL_STEADY. +steady + Added +state +potential +flow +solver. +See +*ICFD_CONTROL_GENERAL. + Weak thermal coupling for conjugate heat transfer is now possible in +See +classic monolithic +approach. +addition +to +*ICFD_CONTROL_CONJ. +the + Windkessel boundary conditions are now available for blood flow. +See *ICFD_BOUNDARY_WINDKESSEL. + It is now possible to output the heat transfer coefficient as a surface +variable in LSPP or in ASCII format on segment sets for a subsequent +solid-thermal only analysis. See *ICFD_DATABASE_HTC. + Two way coupling is now possible with DEM particles. See +*ICFD_CONTROL_DEM_COUPLING. + Modifications introduced in the SUPG stabilization term used in +thermal and conjugate heat transfer problems for improved accuracy +and speed. +◦ Additions and modifications to existing ICFD keywords + *ICFD_BOUNDARY_FSWAVE: +INTRODUCTION +Added a boundary condition for wave generation of 2nd order stokes +waves with free surfaces + *ICFD_CONTROL_FSI: +Added a flag which, when turned on will project the nodes of the +CFD domain that are at the FSI interface onto the structural mesh. +This is recommended for cases with rotation. + *ICFD_CONTROL_MESH: +Added a flag to allow the user control over whether there will be re- +mesh or not. If there is no re-mesh then we can free space used to +backup the mesh and lower memory consumption. + *ICFD_CONTROL_MESH_MOVE: +Added option to force the solver to turn off any mesh displacements. +This can be useful in cases where the mesh is static to save a little bit +of calculation time. + *ICFD_CONTROL_OUTPUT: +Added option to support output in Fieldview format, binary and +ASCII. +When output of the fluid volume mesh is requested, the mesh will be +divided into ten distinct parts, grouping elements in ten deciles based +on the mesh quality (Part 1 has the best quality elements, part 10 the +worst). + *ICFD_CONTROL_POROUS: +Improvements for RTM problems. + *ICFD_CONTROL_TIME: +Added an option to define an initial timestep. +Added an option to shut off the calculation of Navier Stokes after a +certain time leaving only the heat equation. This can be useful to +save calculation times in conjugate heat transfer cases where the fluid +often reaches steady state before the thermal problem. + *ICFD_DATABASE_DRAG: +It is now possible to output the force on segment sets in a FSI run di- +rectly in LS-DYNA compatible format. This can be useful for a sub- +sequent linear FSI analysis running only the solid mechanics part. +Added flag to output drag as a surface variable in LSPP. + *ICFD_DATABASE_FLUX: +Added option to change output frequency + *ICFD_DATABASE_NODOUT: +The user node IDs are now required rather than the internal node IDs + *ICFD_CONTROL_IMPOSED_MOVE: +Added the option to choose between imposing the displacements or +the velocity. + *ICFD_CONTROL_TRANSIENT: +Choose implicit time integration scheme for NS. + *ICFD_CONTROL_DEM_COUPLING: +INTRODUCTION +Added a scale factor for the sphere radius in the computation of the +DEM force. + *ICFD_MODEL_POROUS: +Added a scale factor option on the permeability for model 1 and 2. A +*DEFINE_FUNCTION can also be used. + *MESH_BL: +Added option to generate boundary layer mesh using a growth fac- +tor. +◦ ICFD bug fixes and minor improvements + Fixed bug when multiple *DEFINE_FUNCTIONs were used in an +ICFD problem. Only the last one was taken into account. + LES turbulence model: fixed van Driest damping issue in the bound- +ary layer. LES models can use wall functions. + RANS turbulence models: Standard k-epsilon, realizable k-epsilon, +Wilcox k-omega uses HRN laws of the wall by default while SST and +Spalart Allmaras use LRN. Improvements on the convergence of all +those models. + The DEM particle volume is now taken into account in free surface +problems. + Average shear is now output as a surface variable in the d3plots. + *ICFD_CONTROL_MONOLITHIC +(replaced +*ICFD_CONTROL_GENERAL). +obsolete +is +by + Added more output for the mesh generation indicating the stage of +the meshing process and the amount of elements that are being gen- +erated as a multiple of 10000. Added progress % for the extrusion of +the mesh during the BL mesh generation. + Improvements on the element assemble speed in MPP. + Fixed synchronization problem for the last timestep in an FSI prob- +lem. + More options have been added to the timer output. + Correction of the calculation of the flux in *ICFD_DATABASE_FLUX +in free surface cases. + Boundary layer mesh can go through free-surfaces or mesh size inter- +faces. + The Center of Gravity of the fluid is output in the icfd_lsvol.dat +ASCII file in free surface problems +• Implicit (Mechanical) Solver +◦ Enhanced termination of MPP eigensolver when non eigenmodes are +found. +INTRODUCTION +◦ Implicit was enforcing birth and death times on *BOUNDARY_SPC during +dynamic relaxation contrary to the User's Manual. These times are now +ignored by implicit during dynamic relaxation. +◦ Corrected output of eigenvalues and frequencies to file eigout for the +asymmetric eigenvalue problem. +◦ Enhanced logic that determines when to write out the last state to d3plot +for implicit. +◦ Improved error message for reading d3eigv file for *PART_MODES for the +case when the user inputs a d3eigv file from a different model than intend- +ed. +◦ Corrected the reporting of kinetic and internal energy in file glstat for im- +plicit. +◦ Applied corrections to tied contact in implicit (MPP). This affects slave +nodes coming from other processes. +◦ Corrected output to file d3iter (implicit nonlinear search vectors) for re- +start. +◦ Enhanced termination process when the implicit solver determined an ear- +ly termination. +◦ When implicit springback was following an explicit transient step, the im- +plicit keywords with the _SPR were not properly handled. This is now +corrected. +◦ Added +a +warning +of +*CONSTRAINED_RIGID_BODY_STOPPERS and the Lagrange multiplier +formulation for joints (*CONTROL_RIGID) for explicit. The warning rec- +ommends switching to the penalty joint formulation. +combined +about +use +the +◦ Applied numerous bug fixes to the implicit solver associated with +*CONSTRAINED_INTERPOLATION where there are lots of independent +degrees-of-freedom. +◦ Corrected initialization of MPP tied contact with implicit mechanics when +the implicit phase follows explicit dynamic relaxation. +◦ Fixed an implicit problem where a linear implicit analysis follows inertia +relief computation. +◦ Added gathering of damping terms from discrete elements from implicit +especially for FRF computations and matrix dumping. +◦ Fixed Implicit for the case of multi-step Linear (NSOLVR = 1) with Inter- +mittent Eigenvalue Computation. +◦ Corrected the output to d3iter when 10-noded tets are present. +◦ Keypoints specified in *CONTROL_IMPLICIT_AUTO are now enforced at +the initial time step and on restart from explicit. +◦ Skip frequency damping during implicit static dynamic relaxation, i.e. +IDRFLAG > 5. +◦ *CONTROL_IMPLICIT_ROTATIONAL_DYNAMICS: + The VID of the rotating axis can now be defined by both +*DEFINE_VECTOR and *DEFINE_VECTOR_NODES. It enables the +INTRODUCTION +movement of the rotating axis. Previously, only *DEFINE_VECTOR +could be used to define the VID. + The rotational dynamics now work in MPP. +◦ Shell forms 23 and 24 (high order shells), 1D seatbelts, Hughes-Liu and +spotweld beams (types 1 and 9) are now supported with the implicit accu- +racy option (IACC = 1 in *CONTROL_ACCURACY) to render strong ob- +jectivity for large rigid body rotations. Also, shell type 16 is supported +with implicit accuracy option, resulting in forms 16 and -16 giving the +same solution. +◦ Translational and generalized stiffness joints are now strongly objective for +implicit analysis. See CONSTRAINED_JOINT_STIFFNESS.... +◦ In implicit it may happen that the initial loads are zero, for instance in +forming problems. In addition, the goal is to move a tool in contact with a +workpiece, and the way line search and convergence works, it is hard to +get things going. We now attempt to handle this situation by automatical- +ly associating an augmented load to the prescribed motion simply to get +off the ground. +◦ New tolerances on maximum norms are introduced for convergence in +implicit: ratio of max displacement/energy/residual, and absolute values +of nodal and rigid body translation/rotational residual can be specified. +See DNORM.LT.0 on *CONTROL_IMPLICIT_SOLUTION for defining an +additional card for these parameters DMTOL, EMTOL and RMTOL. Fur- +thermore, maximum absolute tolerances on individual nodal or rigid body +parameters can be set on NTTOL, NRTOL, RTTOL and RRTOL on the +same card. +◦ If ALPHA < 0 on first *CONTROL_IMPLICIT_DYNAMICS card, the HHT +implicit time integration scheme is activated. +• *INITIAL +◦ Fix +*INITIAL_VELOCITY_GENERATION +with +*INCLUDE_TRANSFORM, which was broken due to misplaced condi- +tionals in r100504. +when +used +◦ Fix 3 bugs for *INITIAL_VELOCITY_GENERATION involving omega > 0 +and icid > 0: + When nx = -999. Now the directional cosine defined by node NY to +node NZ will be the final direction to rotate about. In other words, +the direction from node NY to node NZ will not be projected along +icid any more. + When nx != -999, (xc,yc,zc) should not be rotated along icid, since +(xc,yc,zc) are global coordinates. + When +is +*INCLUDE_TRANSFORM, (xc,yc,zc) is transformed. +*INITIAL_VELOCITY_GENERATION +1-182 (INTRODUCTION) +INTRODUCTION +◦ Add +of +the +time +option +ramping +for +*INITIAL_FOAM_REFERENCE_GEOMETRY. The solid elements with +reference geometry and ndtrrg > 0 will restore its reference geometry in +ndtrrg time steps. +incorrect +in +velocity +*INITIAL_VELOCITY_GENERATION, and rotational velocity, omega, is +not zero and *PART_INERTIA is also present. +ICID.ne.0 +ndtrrg, +initial +steps, +when +◦ Fix +◦ Add variable IZSHEAR in *INITIAL_STRESS_SECTION to initialize shear +stress. +◦ Fix incorrect initial velocity for *INITIAL_VELOCITY if IRIGID = -2 and +ICID > 0. +◦ Fix incorrect NPLANE and NTHICK for *INITIAL_STRESS_SHELL when +writing dynain for shell type 9. +◦ Fix *INITIAL_STRAIN_SHELL output to dynain for shell types 12 to 15 in +2D analysis. Write out strain at only 1 intg point if INTSTRN = 0 in +*INTERFACE_SPRINGBACK_LSDYNA and all strains at all 4 intg points +if INTSTRN = 1 and nip = 4 in *SECTION_SHELL. +the +◦ Skip +transformation of +ICID > 0 and +*INCLUDE_TRANSFORM is used to transform the keyword input file +with the *INITIAL_VELOCITY.... keyword. Also echo warning message, +KEY+1109, that the transformation will be skipped since icid is specified. +◦ Fix incorrect transformation of *DEFINE_BOX which results in incorrect +initial velocities +if +initial velocities if the box is used in *INITIAL_VELOCITY. +◦ Fixed *INITIAL_STRESS_DEPTH when used with 2D plane strain and ax- +isymmetric elements. The prestress was being zeroed. +◦ Improved the precision of the +initial deformation calculation for +*INITIAL_FOAM_REFERENCE_GEOMETRY in the single precision ver- +sion. +◦ Fixed stress initialization (*INITIAL_STRESS_SECTION) for type 13 tet el- +ements. The pressure smoothing was causing incorrect pressure values in +the elements adjacent to the prescribed elements. +◦ Add _SET option to *INITIAL_STRESS_SOLID for element sets. +◦ Fix bug +in 3D adaptivity +*INITIAL_TEMPERATURE for adaptive parts. +that users +so +can now define +• Isogeometric Elements +◦ The stability of the trimmed NURBS shell patches has been improved. +◦ Add *LOAD_NURBS_SHELL to apply traction type loading directly on the +surface of NURBS shell. +◦ Users can use the PART option of *SET_SEGMENT_GENERAL to define +segment set of a NURBS patch. The segment set will contain all segments +of interpolated null shell elements. +◦ *ELEMENT_SOLID_NURBS_PATCH: +INTRODUCTION + Isogeometric solid analysis implemented for MPP. + Isogeometric solid analysis implemented for SMP with multiple +CPUs, including consistency (ncpu < 0). + Activate user-defined materials for isogeometric solid. +◦ *ELEMENT_SHELL_NURBS_PATCH: + Isogeometric shell analysis now implemented for SMP with multiple +CPUs, including consistency (ncpu < 0). + Add a power iteration method to get the maximum eigen-frequency +for each isogeometric element. This will be used to set a reasonable +time step for trimmed elements. +◦ *ELEMENT_SHELL_NURBS_PATCH: + Changed the way of projecting the results from isogeometric +(NURBS) elements to the interpolation elements. Now a background +mesh, spanned over the locations of the integration points of the iso- +geometric (NURBS) elements serves as basis to interpolate results +from the integration points to the centroid of the interpolation ele- +ments. This change may lead to slightly different post-processing re- +sults in the interpolation elements. +◦ Add support for trimmed NURBS to work in single precision. Anyway, it +is still recommended to use double precision versions for trimmed NURBS +patches. +◦ Add post-processing of strains and thickness for interpolation shells. +• *LOAD +◦ Fixed bugs affecting discrete beam elements (ELFORM = 6) when used +with staged construction. Here, "dormant" refers to elements that have not +on +as +yet +*DEFINE_STAGED_CONSTRUCTION_PART. +defined +become +active + Dormant discrete beams could still control the timestep and attract +mass-scaling, when they should not do so. + Dormant discrete beams reaching a failure criterion defined on the +*MAT card were deleted, when they should not be. + The displacements output included +displacements occurring while the elements were dormant. Now, the +output displacements are reset to zero at the moment the element be- +comes active. +INTRODUCTION +◦ Fixed +bug +on +*CONTROL_STAGED_CONSTRUCTION had been left blank, and Dy- +namic Relaxation was active, an error termination occurred. +Construction: +Staged +FACT +in +if +◦ Fixed bug: *LOAD_GRAVITY_PART (and also gravity loading applied by +*DEFINE_STAGED_CONSTRUCTION_PART) was failing to account for +non-structural mass when +load: NSM on +*SECTION_BEAM and MAREA on *SECTION_SHELL. +calculating gravity +◦ Fixed bug in *LOAD_VOLUME_LOSS: inconsistent results when run in +SMP parallel. +◦ Fix bugs affecting *LOAD_SEGMENT_FILE: + Remove LOAD_SEGMENT_FILE file size limit (It used to be 200M). + Apply correct pressure on the shared boundary between processors. +◦ Fix GRAV = 1 in *PART which was not were not working correctly with +*LOAD_DENSITY_DEPTH. Make *LOAD_DENSITY_DEPTH work for +Lagrangian 2D elements. +◦ Fix +insufficient +memory +error,SOL+659, +when +using +*LOAD_ERODING_PART_SET with MPP. +◦ Fix incorrect loading when using *LOAD_ERODING_PART_SET with +BOXID defined. +◦ Added *LOAD_SUPERPLASTIC_FORMING for implicit analysis. +◦ *LOAD_SUPERPLASTIC_FORMING box option now works in MPP. +• *MAT and *EOS +◦ *MAT_197 (*MAT_SEISMIC_ISOLATOR) could become unstable when the +parameter DAMP was left at its default value. A workaround was to input +DAMP as a small value such as 0.05. The timestep for *MAT_197 is now +smaller than previously, irrespective of the DAMP setting, and the behav- +ior is now stable even if DAMP is left at the default. +◦ Fixed bug: Timestep calculation was wrong for *MAT_089 solid elements. +Response could be unstable especially for higher values of Poisson's ratio, +e.g. 0.4. +◦ Fixed bug: An error trap was wrongly preventing ELFORM = 15 for +elements with +(*MAT_ARUP_ADHESIVE). + Wedge +*MAT_169 +ELFORM = 15 are now permitted. +◦ *MAT_172 (*MAT_CONCRETE_EC2): +Note that items (1) and (2) below can lead to different results compared to +previous versions of LS-DYNA. + (1) The number of potential cracks in MAT_172 shell elements has +been increased from 2 to 4. MAT_172 uses a fixed crack model: once +the first crack forms, it remains at the same fixed angle relative to the +element axes. Further cracks can then form only at pre-defined an- +INTRODUCTION +gles to the first crack. Previously, only one further crack could form, +at 90 degrees to the first crack. Thus, if the loading direction subse- +quently changed so that the principal tension is at 45 degrees to the +first crack, that stress could exceed the user-defined tensile strength +by a considerable margin. Now, further cracks may form at 90, +45 +and -45 degrees to the first crack. Although the maximum principal +stress can still exceed the user-defined tensile strength, the "error" is +much reduced. There is an option to revert to the 2-crack model as in +R9 (to do this, add 100 to TYPEC). + (2) Add element erosion to MAT_172. This change may lead to dif- +ferent results compared to previous versions, because erosion strain +limits are now added by default. Elements are now deleted when +crack-opening strain becomes very large, or the material is crushed +beyond the spalling limit. Plastic strain in the rebar is considered too. +Previously, these elements that have passed the point of being able to +generate any stress to resist further deformation would remain in the +calculation, and sometimes showed very large non-physical defor- +mations and could even cause error terminations. Such elements +would now be deleted automatically. Default values are present for +the erosion strains but these can be overridden in the input data, see +new input fields ERODET, ERODEC, ERODER. + (3) New history variables 10,11,12 (maximum value so far of through- +thickness shear stress). This is useful for checking results because +MAT_172 cracks only in response to in-plane stress; before cracking +occurs, the through-thickness shear capacity is unlimited. The data +components are: +Ex History Variable 10 - maximum out of 11 and 12 +Ex History Variable 11 - maximum absolute value of YZ shear stress +Ex History Variable 12 - maximum absolute value of ZX shear stress +These are in the element local axis system. Note that these variables +are written only if TYPESC is zero or omitted. TYPESC is a pre- +existing capability that requests a different type of shear check. + (4) Fixed bug. Elastic stiffness for MAT_172 beams was not as de- +scribed in the manual, and the axial response could sometimes be- +come unstable. The bug did not affect shell elements, only beams. + (5) *MAT_172 can now handle models with temperatures defined in +Kelvin (necessary if the model also has heat transfer by radiation). +*MAT_172 has thermally-sensitive material properties hard-wired to +assume temperatures in Centigrade. A new input TMPOFF in +*MAT_172 offsets the model temperatures before calculating the ma- +terial properties. + (6) When the input parameter AGGSZ is defined, the maximum shear +stress that can be transferred across closed cracks is calculated from a +formula that has tensile strength and compressive stress as inputs. In +MAT_172, the tensile strength of concrete is reduced when compres- +INTRODUCTION +sive damage has occurred . Up to now, +compressive damage was therefore influencing the maximum shear +across cracks. However, the Norwegian standard from which the +shear formula is taken treats the tensile strength as a constant. There- +fore, for the purpose of calculating the maximum shear stress across +closed cracks only, the compressive damage effect is now ignored. + (7) Added capability for water pressure in cracks, for offshore appli- +cations. The water pressure is calculated from the depth of the ele- +ment below the water surface (calculated from the z-coordinate). The +water pressure is applied as a compressive stress perpendicular to the +plane of any crack in the element. See new input fields WRO_G and +ZSURF. +◦ *MAT_119 (*MAT__GENERAL_NONLINEAR_6DOF_DISCRETE_BEAM): +Fixed bug in UNLOAD option 2. The bug occurs if an unloading curve has +been left zero (e.g. LCIDTUR) while the corresponding loading curve was +non-zero (e.g. LCIDTR), and UNLOAD = 2. Depending on the computer +system, the symptoms could be harmless or the code could crash. Now, if +the unloading curve is left blank, it is assumed to be the same as the load- +ing curve i.e. load and unload up and down the same curve. That behav- +ior was already implemented for UNLOAD = 1. +◦ Added Equation Of State 19 (*EOS_MURNAGHAN). Used extensively for +fluid modeling in SPH through Weakly-Compressible formulation, in con- +junction with SPH formulations 15 (fluid form) and 16 (normalized fluid +form). +◦ *MAT_ADD_FATIGUE: Added a new form of Basquin equation to define +material's SN curve: LCID = -3: S = a*N^b, where a and b are material con- +stants. +◦ Add the option of A0REF for *MAT_FABRIC. That allows the option of +using reference geometry to calculate A0 for the purpose of porosity leak- +age calculation. +◦ Add optional parameter DVMIN for *MAT_ADD_PORE_AIR to define the +min volume ratio change to trigger pore air flow analysis. +◦ *DEFINE_HAZ_PROPERTIES: +◦ Distance of shell from the weld center is treated consistently under MPP +and the shell material's yield stress is scaled properly. +◦ *MAT_168 and *MAT_279: Fixed support for element erosion. +◦ *MAT_092: Improved of implicit convergence for shells. +◦ *MAT_224: Fixed bug where wrong shear modulus was used in EOS. +◦ *MAT_270: Increased stability for thickness strain iterations for shells. +◦ *MAT_240: Added support for cohesive shell formulation +/-29. +◦ Scale load curve, LCSRS, of *MAT_ADD_EROSION when used with +*INCLUDE_TRANSFORM. +INTRODUCTION +◦ Fix +incorrect +using +results +*MAT_TABULATED_JOHNSON_COOK/*MAT_224 with table LCKT de- +fined and the first abscissa value, temperature, is negative. +table +◦ Fix spurious element deletion when using +for LCF +when +*MAT_TABULATED_JOHNSON_COOK/*MAT_224 +*MAT_TABULATED_JOHNSON_COOK_GYS/*MAT_224GYS. +in +and +◦ Error terminate with message, KEY+1142, if *MAT_ADD_EROSION is ap- +plied to resultant materials 28,116,117,118,130,139,166,170 and 98(with 1 +intg point). +◦ Increase +robustness +of +*MAT_033/*MAT_BARLAT_ANISOTROPIC_PLASTICITY for solids. +◦ Fix +input +error +when +*MAT_ELASTIC_WITH_VISCOSITY_CURVE/*MAT_060c +LCID = 0. +using +when +◦ Fix seg fault when using shell type 15, axisymmetric volume weighted, +with *MAT_ADD_EROSION and also materials with equation-of-states. +◦ Store computed yield strength as history variable #6 for *MAT_255. +◦ Fix +for +inconsistency +*MAT_MODIFIED_PIECEWISE_LINEAR_PLASTICITY/*MAT_123 when +ncpu < 0. +◦ Include original volume output to dynain file for 2D analysis when materi- +als with an equation-of-state are used. This is needed to compute the de- +formation gradient when initializing a run using the dynain file. +◦ Fix improper stress initialization using *INITIAL_STRESS_SHELL via +dynain for *MAT_018/*MAT_POWER_LAW_PLASTICITY with VP = 1.0. +◦ Make +for +*MAT_170/*MAT_RESULTANT_ANISOTROPIC, i.e. with material coor- +dinate system using *DEFINE_COORDINATE_(OPTION). +AOPT < 0 +work +◦ Fix +incorrect +operation +*MAT_MODIFIED_PIECEWISE_LINEAR_PLASTICITY/*MAT_124 +*MAT_PLASTICITY_WITH_DAMAGE/*MAT_081/*MAT_082. +TDEL +of +for +and +◦ Fix incorrect damping when using *DAMPING_PART_STIFFNESS for +and +*MAT_16/*MAT_PSEUDO_TENSOR +*EOS_TABULATED_COMPACTION. +◦ Fix incorrect computation of bulk modulus which caused complex sound +speed error when using *EOS_TABULATED/EOS_09 with tabulated in- +put. +◦ Fix moving part with *MAT_220 during dynamic relaxation when veloci- +ties are initialized. +◦ Fix +for +*MAT_065/*MAT_MODIFIED_ZERILLI_ARMSTRONG for shells when +VP = 1. +convergence +issue +◦ Error terminate with message, KEY+1115, if _STOCHASTIC option is in- +no +for materials +10,15,24,81,98, +voked +123 +but +or +INTRODUCTION +*DEFINE_STOCHASTIC_VARIATION or *DEFINE_HAZ_PROPERTIES +keyword is present in the input file. +◦ Fix spurious error termination when using *DEFINE_HAZ_PROPERTIES +with adpativity. +◦ Fix +incorrect +results +or +seg +fault +for +*MAT_FU_CHANG_FOAM/*MAT_083 if KCON > 0.0 and TBID.ne.0. +◦ If SIGY = 0 and S = 0 in *MAT_DAMAGE_2/*MAT_105, set S = EPS1/200, +where EPS1 is the first point of yield stress input or the first ordinate point +of the LCSS curve. +◦ Allow *MAT_ENHANCED_COMPOSITE_DAMAGE/*MAT_054 failure +mechanism to work together with *MAT_ADD_EROSION for shells. +◦ Fix incorrect erosion behavior if *MAT_ADD_EROSION is used with fail- +for +ure +*MAT_123/*MAT_MODIFIED_PIECEWISE_LINEAR_PLASTICITY. +defined +criteria +◦ Implement *MAT_FHWA_SOIL/*MAT_147 for 2D analysis, shell types 13, +14 and 15. +◦ Implement +scaling +of +failure +strain +for +*MAT_MODIFIED_PIECEWISE_LINEAR_PLASTICITY_STOCHASTIC/* +MAT_123_STOCHASTIC for shells. +◦ Fix +for +*MAT_LINEAR_ELASTIC_DISCRETE_BEAM/*MAT_066 when using +damping with implicit (static) to explicit switching. +behavior +incorrect +◦ Fixed *MAT_FABRIC/*MAT_034 with the negative unloading curve op- +tion. When searching for the intersection point of the load and unload +curves, and extrapolation of one of the curves was needed to find the inter- +section point, the extrapolated stress was calculated incorrectly causing +unpredictable behavior. +◦ Fixed fabric material forms 0 and 1 when used with a reference geometry. +There were two problems, both occurring when there are mixed quad and +triangular elements in the same block. A flaw in the strain calculation was +leading to possible NaN forces in the elements. When a reference geome- +try was not used, the forces from triangular elements in mixed element +blocks were 2 times too high. +◦ Added a new option for *MAT_SPOTWELD called FMODE. The FMODE +option is available for DMGOPT = 10, 11, and 12. When the failure func- +tion is reached, and when FMODE > 0.0 and < 1.0, the value of FMODE +will determine if a weld will fail immediately, or will have damage initiat- +ed. The failure function may include axial, shear, bending and torsion +terms. If the sum of the squares of the shear and torsion terms divided by +the sum of the square of all terms is greater than FMODE, then the weld +will fail immediately. Otherwise, damage will be initiated. +◦ Enabled OPT = -1 on *MAT_SPOTWELD for brick elements which had not +worked previously. Also, fixed TRUE_T when used with brick element +forms 0, 1, and -1. +INTRODUCTION +◦ Fixed spotwelds with DMGOPT = 12 by removing warning STR+1327 +which made it impossible to set a small value of RS without triggering this +warning, or without setting EFAIL smaller. Setting EFAIL small however +could lead to damage initiation by plastic strain when the user wanted on- +ly initiation by the failure function. +◦ If DMGOPT = 10, 11, or 12 and EFAIL = 0, on *MAT_SPOTWELD, damage +will now initiate only by the failure function. If EFAIL > 0, then damage +will initiate be either then failure function or when plastic strain exceeds +EFAIL. Prior to this version, damage could initiate when plastic strain ex- +ceeds zero if the user set EFAIL = 0. This behavior is still true for +DMGOPT = 0, 1, or 2, but no longer for DMGOPT = 10, 11, or 12. +◦ Allow solid spot welds and solid spot weld assemblies to have up to 300 +points in the running average that is used to smooth the failure function. +In other words, up to NF = 300 is possible. +◦ Fixed a problem with brick spot weld assemblies when OPT = 0 failure is +used without defining any weld resultant values. Welds were being im- +mediately deleted. +◦ Added new PID option for *DEFINE_SPOTWELD_FAILURE (applies to +*MAT_SPOTWELD, OPT = 10). Changes the Card 3 input for static +strength values to use part set ID’s rather than material ID’s. +◦ Modified shell *MAT_214/*MAT_DRY_FABRIC to calculate fiber strains +based on the current distance between the points where the fibers intersect +with the element edges. Previously, they were calculated from the rate-of- +deformation, but this was not as accurate as the new total strain measure. +◦ Fixed unit scaling for GAMAB1 and GAMAB2 on *MAT_DRY_FABRIC. +◦ Reworked +We were incorrectly transforming them as stress. +stress +in +*MAT_225/*MAT_VISCOPLASITC_MIXED_HARDENING to prevent a +divide by zero. +update +plastic +the +◦ Enabled *MAT_ADD_EROSION to be used with beams that have user de- +fined integration. Memory allocation was fixed to prevent memory errors. +◦ Fixed *MAT_106 when used with tshell form 5 or 6. The elastic constants +used in the assumed strain field were not reasonable. +◦ Fix issue that could have led to problems using *MAT_054 (or *MAT_058 +or *MAT_158) in combination with TFAIL/TSIZE.gt.0.0 and damping. +◦ *MAT_054 - *MAT_ENHANCED_COMPOSITE_DAMAGE: + Add possibility to use failure criterion in *MAT_054 for solids in a +transversal isotropic manner. It is assumed that the material 1- +direction is the main axis and that the behavior in the 2-3 plane is iso- +tropic. This feature is invoked by setting TI = 1 in *MAT_054. +◦ *MAT_058 - *MAT_LAMINATED_COMPOSITE_FABRIC: +INTRODUCTION + Bugfix for shear stiffness behavior in *MAT_058 when using a table +definition for GAB and only providing stress-strain-curves for posi- +tive shear. + Bugfix for strain-rate dependent stiffness behavior in *MAT_058 +when using a table definition for EA, EB or GAB under compressive +loading. + Add default values for strengths (XT,XC,YT,YC,SC) 1.e+16 for +*MAT_058. If no values for the strengths were defined, unpredictable +things could have happened. +◦ *MAT_138 - *MAT_COHESIVE_MIXED_MODE: + Store total mixed-mode and normal separation (delta_II & delta_I) on +history variables 1&2 +*MAT_COHESIVE_MIXED_MODE +(*MAT_138). This is only for post-processing and should not lead to +any changes in the results. +for +◦ *MAT_157 - *MAT_ANISOTROPIC_ELASTIC_PLASTIC: + Add Tsai-Hill failure criterion (EXTRA = 2). + Allow +strain-rate +values +dependent +(XT,XC,YT,YC,ZT,ZC,SXY,SYZ,SZX) using *DEFINE_CURVE. This is +available for Tsai-Wu (EXTRA = 1) and Tsai-Hill. +strength + Fixed bug in using *MAT_157 with IHIS.gt.0 for shells. Thickness +strain update d3 was not correct and plasticity algorithm may have +failed. + Add additional option to IHIS in *MAT_157 for SHELLs. + Now also the strength values (XT,XC,YT,YC,SXY) may be initialized +via *INITIAL_STRESS_SHELL. See variable IHIS and remarks in the +User's Manual for details of initializing various blocks of material pa- +rameters. +◦ *MAT_215 - *MAT_4A_MICROMEC: + Add new material *MAT_215 that is a micromechanical material +model that distinguishes between a fiber/inclusion and a matrix ma- +terial. The material is intended for anisotropic composite materials, +especially for short (SFRT) and long fiber thermoplastics (LFRT). +This model is available for shells, tshells and solids. +◦ *MAT_225 - *MAT_VISCOPLASTIC_MIXED_HARDENING: + Fixed +*MAT_225 +(*MAT_VISCOPLASTIC_MIXED_HARDENING) when using a table +for LCSS together with kinematic hardening. +bug +in +INTRODUCTION +◦ *MAT_261 - *MAT_LAMINATED_FRACTURE_DAIMLER_PINHO: +*MAT_262 - *MAT_LAMINATED_FRACTURE_DAIMLER_CAMANHO: + Allow +for +table +input +for mats +261/262.Table represents fracture toughness vs. element length vs. +strain rate (shells, tshells, solids) +mats +toughness values +261/262 +fracture +when +bug +in + Fixed +together with RYLEN = 2 +using +in +*DAMPING_PART_STIFFNESS +*CONTROL_ENERGY. + Correct shear failure behavior in *MAT_262. This will most probably +have no effect to any real application, but could be seen in very spe- +cial 1-element tests. +◦ Changed +storage +*MAT_249 +(*MAT_REINFORCED_THERMOPLASTIC). A new variable POSTV con- +trols which variables are written and at what history variable location in +d3plot. +variables +history +for +of +◦ *MAT_254 (*MAT_GENERALIZED_PHASE_CHANGE) can now be used +with shell elements and thermal thick shells. +◦ Added flag 'EZDEF' to *MAT_249_UDFIBER. In this case the last row of +the deformation gradient is replaced by 0-0-1. +damage +limitation +opt. +◦ Add +curve/table +LCDLIM +for +*MAT_ADD_GENERALIZED_DAMAGE. +◦ Add +pre-defined +damage +tensors +option +PDDT +to +*MAT_ADD_GENERALIZED_DAMAGE. +◦ *MAT_ADD_GENERALIZED_DAMAGE now works for solid elements +(only shells in R9). +◦ Add optional failure criterion FFCAP to *MAT_100 with OPT = -1 or 0. +◦ Enable *MAT_ADD_COHESIVE to be used in implicit analysis. +◦ Add alternative version of *MAT_280 invoked by new flag on 1st card. It +is a physically based damage model with 4 new parameters. +◦ Enable *DEFINE_CONNECTION_PROPERTIES' option PROPRUL>=2 to +be used with spotweld clusters, i.e. not only 1 hex element but several (via +*DEFINE_HEX_SPOTWELD_ASSEMBLY +on +*CONTROL_SPOTWELD_BEAM). +RPBHX > 1 +or +◦ Enable *MAT_ADD_EROSION to be safely used with material models that +have more than 119 history variables, for now the new limit is 169 (e.g. +necessary for *MAT_157 with IHIS = 7). +◦ Add Tsai-Wu failure criterion to *MAT_157 for solid and shell elements +invoked by EXTRA = 1 on card 6 and corresponding parameters on cards 8 +and 9. +◦ Add viscoelastic option to *MAT_187 (SAMP-1). Rate dependent Young's +modulus and associated settings can be defined on new optional card 5. +◦ Add new option IRNG for *DEFINE_STOCHASTIC_VARIATION to gov- +ern random number generation (deterministic or true random). +INTRODUCTION +◦ Add option to define element size dependent parameters EN and SN for +*MAT_120 and *MAT_120_JC by setting them to negative values (curves). +◦ Minor improvements for *MAT_252: Optional output of damage initiation +information and more post-processing history variables. +◦ If the first abscissa value of *MAT_224's failure strain curve LCG is nega- +tive, it is assumed that all abscissa values are natural logarithms of a strain +rate. +◦ Put *MAT_100_DA's "failure function" value to history variable 18. +◦ Add optional in-plane failure strain to *MAT_169 (ARUP_ADHESIVE): +new input parameter FSIP. +◦ *MAT_USER_DEFINED_MATERIAL_MODELS now provides a few more +variables for cohesive elements, i.e. additional arguments in subroutines +umatXXc: temperature, element size, implicit rejection flag, integration +point identifier, and total number of integration points. +◦ A modified version of the 3-parameter Barlat model (*MAT_036) is intro- +duced as *MAT_EXTENDED_3-PARAMETER_BARLAT. In this model, +hardening in 00, 45, 90, biaxial and shear can be specified as load curves. +Furthermore, r-values in 00, 45, 90, biaxial and shear can be specified in +terms of load curves vs plastic strain or constants. This is an extension of +hardening law 7 of the original 3-parameter Barlat model. +version +implicit +◦ Improve +of +*MAT_098/*MAT_SIMPLIFIED_JOHNSON_COOK. +◦ *MAT_181/*MAT_SIMPLIFIED_RUBBER/FOAM is now supported for +2D implicit simulations. +◦ Fixed issue in which *MAT_WINFRITH_CONCRETE wrote d3crack data +too frequently. +◦ *EOS_JWL now has an AFTERBURN option. This adds afterburn energy +to the EOS, where the energy can be added at a constant or linear rate, or +can be added according to Miller's extension. +◦ +◦ *MAT_084 +(*MAT_WINFRITH_CONCRETE) with predefined units +(CONM < 0) is now transformed correctly with *INCLUDE_TRANSFORM. +◦ User-defined materials for Hughes-Liu beams can now be used with im- +plicit analysis by defining the appropriate tangent modulus in the supplied +routine urtanb. +◦ User-defined cohesive materials can now be used with implicit analysis by +defining the appropriate tangent stiffness. +◦ *MODULE for user-defined materials and other user-defined capabilities: + A new command line option "module = filename" is added to load +one module file without changing the input deck. It provides back +compatibility to input deck without the MODULE keywords. + The system paths defined in LD_LIBRARY_PATH are also included +for searching module files for those filenames start with "+". +INTRODUCTION +◦ Add +shell +implementation +to +*MAT_277 +(*MAT_ADHESIVE_CURING_VISCOELASTIC). +◦ Add *MAT_278 for carbon fiber prepreg compression forming simulation. +This material model is available for both solid and shell formulations. +◦ Add *MAT_293 non-orthogonal material model for carbon fiber prepreg +forming simulation. This material model is only available for shell formu- +lations. +◦ *MAT_260A: + Extend *MAT_260A to include solid elements. + Add a new option XUE for Xue's fracture criteria/theory for +*MAT_M260A (solid elements only). +◦ *MAT_260B: + Set default values for P's and G's in *MAT_260B. + Add a length scale to the fracture limit. The fracture limit strongly +depends on the length scale in the measurement. + Add a new fracture criterion to *MAT_260B (Xue and Wierzbicki, Int. +J. solids and Structures 46 (2009) 1423-1435). When the option XUE +is activated, an additional card is needed, for example: + $ ef0 plim q gama m + 0.70 925.7 0.970 0.296 2.04 +◦ *MAT_037: + Improve *MAT_037 with negative R value in implicit calculation. +The modification will allow the implicit method stress calculation to +be more accurate. + Add a new option NLP2 to calculate formability index in *MAT_037. +The previous method (option NLP_FAILURE) was based on the ef- +fective strain method, which assumes that necking happens at one in- +stant. In fact, it might happen over a longer process. The new +method calculates the damage accumulation. +◦ Add *MAT_165B (*MAT_PLASTIC_NONLINEAR_KINEMATIC_B) for +shells and solids. +• MPP +◦ Fix the report of decomp balance (shown as "Normalized element costs as- +signed during decomposition" in the d3hsp file), which was broken in +r109760 +◦ MPP decomposition has not been properly balanced since r112652 due to a +bug in that revision +INTRODUCTION +◦ Fix MPP +SYNC +error due +to +inconsistent +summation +in +*CONTACT_SLIDING_ONLY_PENALTY. +◦ Allow real values as the scale multipliers for "memory=" on the command +line. For example, "memory = 2.5G memory2 = 1.1G" and the like. +◦ MPP: fix support for nlq setting in *CONTROL_SOLUTION which was not +being honored on processors other than 0. +◦ Significant improvements in MPP groupable routines for FORMING con- +tact. +◦ MPP: increase contact release distance for SINGLE_SURFACE contacts in +the case of a node coming into contact with a solid element. The previous +interpretation was releasing when the contact penetration was 0.5*solid +thickness, but now when the node passes below the solid surface by +0.5*solid thickness (which is different by the half thickness of the slave ma- +terial, in the case of a shell slave node). +◦ MPP: fix for viscous damping in automatic tiebreak contact. +◦ Implement new bucket sort based extent testing for MPP single surface +contact. +◦ Added +MPP +support +for +*CONTACT_AUTOMATIC_SURFACE_TO_SURFACE_LUBRICATION. +◦ Fixed *CONTROL_MPP_PFILE so that +it honors ID offsets from +*INCLUDE_TRANSFORM for parts, part sets, and contact IDs referenced +in "decomp { region {" specifications. +◦ Furthermore, such a region can contain a "local" designation, in which case +the decomposition of that region will be done in the coordinate system lo- +cal to the include file, not the global system. For example: +◦ *CONTROL_MPP_PFILE decomp { region { partset 12 local c2r 30 0 -30 0 1 +0 1 0 0 } } would apply the c2r transformation in the coordinate system of +the include file, which wasn't previously possible. The local option can be +useful even if there are no such transformations, as the "cubes" that the de- +composition uses will be oriented in the coordinate system of the include +file, not the global system. +◦ Furthermore, the following decomposition related keywords now have a +_LOCAL option, which has the same effect: + *CONTROL_MPP_DECOMPOSITION_PARTS_DISTRIBUTE_LOCA +L + *CONTROL_MPP_DECOMPOSITION_PARTSET_DISTRIBUTE_LO +CAL + *CONTROL_MPP_DECOMPOSITION_ARRANGE_PARTS_LOCAL + *CONTROL_MPP_DECOMPOSITION_CONTACT_DISTRIBUTE_L +OCAL +◦ MPP job performance profiles are output to both .csv and .xy files. +• OUTPUT +INTRODUCTION +◦ Fix for writing d3plot file when individual output states exceed 8GB in +single precision +◦ Added new option *INTERFACE_SPRINGBACK_EXCLUDE to exclude +selected portions from the generated dynain file. +◦ Add a new option to *INTERFACE_COMPONENT_FILE to output only 3 +degrees of freedom to the file even if the current model has 6. +◦ Fix missing plastic strain +*DATABASE_EXTENT_BINARY +*INTERFACE_SPRINGBACK. +tensors +is +in d3plot when STRFLG +set +INTSTRN = 1 +and +in +in +◦ Fix no output to bndout when run with q = remap even though the key- +word *DATABASE_BNDOUT was present in the remap run but was not +present in the initial run. +◦ Fix d3plot output frequency which was different from the dt specified in +is +*DATABASE_BINARY_D3PLOT when *CONTACT_AUTO_MOVE +used. +◦ Fix stress output to elout for solid elements which was in the global coor- +in +in +coordinates when CMPFLG = 1 +dinates +*DATABASE_EXTENT_BINARY +*DATABASE_ELOUT. +OPTION1 > 0 +instead +local +and +of +◦ Fix incorrect mass properties for solids in ssstat file when using +*DATABASE_SSSTAT_MASS_PROPERTY. +◦ Fix seg +fault during writing of dynain +in +*INTERFACE_SPRINGBACK +in +*DATABASE_EXTENT_BINARY and the *DATABASE_EXTENT_BINARY +comes after *INTERFACE_SPRINGBACK. +STRFLG.ne.0 +INSTRN = 1 +and +file +if +◦ If HYDRO is nonzero in *DATABASE_EXTENT_BINARY, LS-PrePost will +now combine the solid and shell internal energy densities when fringing +'Internal Energy Density' in the Misc menu. +◦ By putting SIGFLG/EPSFLG = 3 in *DATABASE_EXTENT_BINARY, the +stresses and plastic trains are excluded not only for shell elements but also +for solids. This applies to d3plot and d3eigv. +◦ Added new file option *DATABASE_BINARY_INTFOR_FILE to define +interface file name. +◦ Fixed +legend +in +bndout +in +the +case +of multiple +*BOUNDARY_PRESCRIBED_MOTION_SET_ID. +◦ Fix +d3part +corrupt +data +*DATABASE_EXTENT_BINARY. +◦ Fixed the legend of ssstat in binout. +◦ Added *DATABASE_EXTENT_SSSTAT_ID. The subsystem id will be in- +DECOMP = 4 +caused +by +in +cluded in the ASCII ssstat file. +◦ Fixed +bug +*CONTROL_OUTPUT. +in +stbout +(seatbelt +output) +if NEWLEG = 0 +in +◦ Fixed bug in which DECOMP = 2 corrupted d3part. +◦ Fixed d3plot bug if dynamic relaxation was activated in the input deck. +INTRODUCTION +◦ Added another digit for coordinates in *NODE in dynain, e.g., what was +written as 0.999266236E+00 is now written as 9.992662368E+00. +◦ Added *DATABASE_EXTENT_BINARY_COMP for alternative (simpler) +control of output to d3plot and d3eigv. + Output control flags: 0-no 1-yes + IGLB : Global data + IXYZ : Current coordinate + IVEL : Velocity + IACC : Acceleration + ISTRS: 6 stress data + plastic strain + ISTRA: 6 strain data + ISED : Strain energy density +command +regular +This +*DATABASE_EXTENT_BINARY but will disable most of the options in +the latter, including output of extra history variables. +combination with +can be used +in +◦ Bugfix: *DATABASE_TRACER without the optional NID parameter was +read incorrectly when used with *INCLUDE_TRANSFORM, but is now +fixed +◦ Fixed incomplete output from Windows version of LS-DYNA. This affect- +curvout +(*DATABASE_TRACER_DE) +demtrh +and +ed +(*DATABASE_CURVOUT). +• Restarts +◦ Enable definition of sensors in full restarts. +◦ For a small restart in MPP, the value of "memory=" (M1) needed for each +processor is stored in the dump files. This is the minimum requirement to +read back the model info. If the value of "memory2=" (M2) is specified on +the command line, the code will take the maximum of M1 and M2. +input when +error +*INITIAL_VELOCITY_GENERATION +*CHANGE_VELOCITY_GENERATION together in a full deck restart. +using +and +structured +during +◦ Fix +input +◦ Fix incorrect full deck restart analysis if initial run was implicit and the full +deck restart run is explicit. This affects MPP only. +◦ Fix insufficient tying of nodes when doing full deck restart and the contact +is newly added to the restart involving newly added parts. This applies to +SMP contact only. +◦ Fix incorrect velocity initialization for SMP full deck restart when using +and +*INITIAL_VELOCITY_GENERATION +*INITIAL_VELOCITY_GENERATION_START_TIME. +◦ Fix incorrect initialization of velocities for SMP full deck restart when us- +ing *CHANGE_VELOCITY_OPTION & *INITIAL_VELOCITY_OPTION. +INTRODUCTION +Velocities of existing parts defined by *STRESS_INITIALIZATION should +not be zeroed. +◦ Fix *CHANGE_CURVE_DEFINITION for curve specifying d3plot output. +◦ Fixed bug in full deck restart if the new mesh has different part numbers. +• *SENSOR +◦ Fix +a +bug +for +*CONSTRAINED_JOINT_STIFFNESS, that was triggered when the force +refers to a local coordinate system. +*SENSOR_JOINT_FORCE +regarding +◦ Add the option of "ELESET" to *SENSOR_CONTROL to erode elements. +◦ Add the option of NFAILE to *SENSOR_DEFINE_MISC to track number of +eroded elements. +◦ Fix a bug that was triggered when using a sensor to control spotwelds. +The bug was triggered when the spotweld-connected nodal pairs happen +to belong to more than 1 core (MPP only). +◦ Add FAIL option to *SENSOR_DEFINE_ELEMENT to track the failure of +element(s). +◦ Fix a bug related to *SENSOR_DEFINE_FUNCTION when there are more +than 10 sensor definitions. +◦ Effect of TIMEOFF +TYPE = PRESC-ORI. +◦ *SENSOR_CONTROL +in *SENSOR_CONTROL +is +implemented +for +can +be +used +to +control +*BOUNDARY_PRESCRIBED_ORIENTATION_RIGID. +◦ Add optional filter id to SENSORD of *DEFINE_CURVE_FUNCTION. +◦ Enable +*CONSTRAINED_JOINT_..._LOCAL +to be monitored by +*SENSOR_DEFINE_FORCE. +◦ Allow moments +in SPCFORC and BNDOUT +to be +tracked by +*SENSOR_DEFINE_FORCE. +◦ Fix *SENSOR_CONTROL using TYPE=“PRESC-MOT” which was not +switching at all. +• SPG (Smooth Particle Galerkin) +◦ MPP is ready in 3D SPG fluid particle stabilization (ITB = 1 & 2 in +*SECTION_SOLID_SPG). +◦ Added one SPG control parameter (itb = 2) for semi-brittle fracture analy- +sis. In comparison to itb = 0 or itb = 1, itb = 2 is more efficient in modeling +the fragmentation and debris in semi-brittle fracture analysis such as im- +pact and penetration in concrete materials. +◦ Fixed a bug related to E.O.S. in SPG. +◦ Removed some temporary memory allocations to improve efficiency. +◦ Changed the sequence of SPG initialization so that all state variables are +properly initialized. +INTRODUCTION +◦ Subroutines were developed for SPG failure analysis with thermal effects. +Both explicit and implicit (diagonal scaled conjugate gradient iterative on- +ly) SPG thermal solvers are available in SMP version only. However, +thermal effect is applied only on material properties, which means thermal +induced deformation (i.e., thermal strain or thermal expansion) is not cur- +rently included. +◦ Modified *MAT_072R3 for SPG method in concrete applications. +◦ Fixed a bug for SPG method in using continuum damage mechanics. (ID- +AM = 0). +◦ Added the “fluid particle algorithm” (itb = 1) to SPG method. This algo- +rithm is implemented in R10.0 as an alternative to the (itb = 0) option in +previous version to enhance the numerical stability for SPG method. Users +are recommended to use this new option for their ductile failure analysis. +• SPH (Smooth Particle Hydrodynamics) +◦ Add ITHK flag in *CONTROL_SPH, card 3. If flag is set to 1, the volume +of the SPH particles is used to estimate a node thickness to be employed by +contacts. + Affects +*AUTOMATIC_NODES_TO_SURFACE +and +*CONTACT_2D_NODE_TO_SOLID. + The thickness calculated by ITHK = 1 is used only if SST or OFFD are +set to zero in the contact cards definitions. +◦ Add SOFT = 1 option to *CONTACT_2D_NODE_TO_SOLID. This should +help obtain reasonable contact forces in axisymmetric simulations. Default +penalty PEN is 0.1 when SOFT = 1. +◦ Implemented non-reflecting boundary conditions for SPH using a new +keyword *BOUNDARY_SPH_NON_REFLECTING. +◦ Bug fix for renormalized SPH formulations with symmetry planes. The +renormalization was slightly incorrect in the vicinity of symmetry planes. +◦ Density smoothing in SPH formulations 15 and 16 is now material sensi- +tive. The smoothing only occurs over neighbors of the same material. +◦ Resolved an MPP bug in SPH total Lagrangian formulations (FORM = 7/8) +which was causing strain concentrations at the interfaces between CPU +zones. +◦ SPH total Lagrangian (FORM = 7/8) in SMP was pretty much serial, hence +much slower than forms 0 or 1. SPH with FORM 7 and 8 now scales +properly. +◦ Added support for FORMs 0/1 in axisymmetric. Until now, renormaliza- +tion was always active (equivalent to FORM = 1) which can be problematic +for very large deformations or material fragmentation. +◦ Improved tracer particles output for SPH: Use normalized kernel function +for interpolation between particles. +INTRODUCTION +◦ Implemented enhanced fluid flow formulations (FORMs 15/16) with pres- +sure smoothing. +◦ Recode SPH neighborhood search algorithm to reduce the memory re- +quirement and produce consistent results from MPP and HYBRID code. +◦ *DEFINE_ADAPTIVE_SOLID_TO_SPH now reports both active and inac- +tive adaptive SPH particles in the fragment file sldsph_frag. This file gives +a report of nodal mass, coordinates, and velocities. +◦ MPP now supports: + SPH type 3 inflow + Multiple *BOUNDARY_SPH_FLOW + Bulk viscosity option for SPH +◦ Sort SPH by part and then node ID to ensure consistent results while +changing order of input files. +◦ *DEFINE_SPH_TO_SPH_COUPLING: + Corrected the SPH sphere radius (half of the particles distance) for +node to node contact detecting algorithm. + Updated masses for SPH node to node coupling with damping con- +tact force option. + Added a new option (Soft = 1) for SPH to SPH coupling: contact stiff- +ness comes from particles masses and time step for softer contact. +◦ *DEFINE_ADAPTIVE_SOLID_TO_SPH: + Updated temperature transfer (from solid elements to SPH particles) +when converting solid elements into SPH particles with ICPL = 1, +IOPT = 0. + Bug fixed when part ID for newly generated SPH particles is smaller +than the original SPH part ID. + Introduced a new pure thermal coupling between SPH part and solid +parts with ICPL = 3 and IOPT = 0 option (no structural coupling pro- +vided). + Added a thermal coupling conductivity parameter CPCD. Applies to +ICPL = 3 option. + Normalized the nodal temperatures for the corner SPH particles with +ICPL = 3 and IOPT = 0 option (MPP only). + Extended ICPL = 3 and IOPT = 0 option to Lagrangian formulation +(form = 7, 8). +◦ *BOUNDARY_SPH_SYMMETRY_PLANE: + Added in an error message if TAIL and HEAD points are at the same +location. +INTRODUCTION +◦ *CONTACT_2D_NODE_TO_SOLID: + Added a variable OFFD to specify contact offset. +◦ Added a new option IEROD = 2 in *CONTROL_SPH in which SPH parti- +cles that satisfy a failure criterion are totally eactivated and removed from +domain interpolation. This is in contrast to IEROD = 1 option in which +particles are partially deactivated and only stress states are set to zero. +◦ Added *MAT_SPH_VISCOUS (*MAT_SPH_01) for fluid-like material be- +havior with constant or variable viscosity. Includes a Cross viscosity mod- +el. +◦ Output strain rates for SPH particles to d3plot, d3thdt, and sphout file. +◦ Added support of *MAT_ADD_EROSION, including GISSMO and DIEM +damage, for SPH particles. +◦ Echo failed SPH particles into d3hsp and messag file. +◦ *DEFINE_SPH_INJECTION: + Changed the method of generating SPH particles. SPH particles will +be generated based on the injection volume (injection area*injection +velocity*dt)*density from the material model, resulting in more con- +sistent particle masses and particle distribution. + Offset injecting distance inside each cycle so that outlet distance will +be consistent for different outlet SPH layers. + Corrected mass output in d3hsp. +• Thermal Solver +◦ Modify the thermal solver routines so they return instead of terminating, +so that *CASE works properly. +◦ *MAT_THERMAL_USER_DEFINED: Fixed bug in element numbering for +IHVE = 1. +◦ Accept +load +in +*CONTROL_THERMAL_TIMESTEP. As usual if a negative integer num- +ber is given its absolute value refers to the load curve id. +for dtmin, dtmax and dtemp +curve +input +◦ The temperature results for the virtual nodes of thermal thick shells are +now accounted for in *LOAD_THERMAL_D3PLOT. For the mechanics- +only simulation thermal thick shells have to be activated. +◦ New contact type for thermal solver that models heat transfer from and to +a shell edge onto a surface (*CONTACT_..._THERMAL with ALGO > 1): + Shells have to be thermal thick shells. + Shells are on the slave side. + So far only implemented for SMP. + Includes support for quads and triangles. +INTRODUCTION +◦ New keyword *BOUNDARY_THERMAL_WELD_TRAJECTORY for weld- +ing of solid or shell structures. + Keyword defines the movement of a heat source on a nodal path +(*SET_NODE). + Orientation given either by vector or with a second node set. + Works for coupled and thermal only analyses. + Allows for thermal dumping. + Different equivalent heat source descriptions available. + Can also be applied to tshells and composite shells. + Weld torch motion can be defined relative to the weld trajectory. +◦ Solid element formulation 18 now supports thermal analysis. +◦ Thermal solver now supports the H8TOH20 option of *ELEMENT_SOLID. +This includes support of *INITIAL_TEMPERATURE condition for the ex- +tra 12 nodes generated by H8TOH20. +◦ Thermal solver now supports the H8TOH27 option of *ELEMENT_SOLID. +◦ Explicit Thermal Solver + *CONTROL_EXPLICIT_THERMAL_SOLVER: Implement an explicit +thermal solver and adapt it to support multi-material ALE cases. + *CONTROL_EXPLICIT_THERMAL_PROPERTIES: Enter +thermal +properties for the explicit thermal solver. + *CONTROL_EXPLICIT_THERMAL_CONTACT: Implement a ther- +mal contact for the explicit thermal solver. + *CONTROL_EXPLICIT_THERMAL_ALE_COUPLING: Implement a +thermal coupling between ALE and Lagrangian structures for use by +the explicit thermal solver. + *CONSTRAINED_LAGRANGE_IN_SOLID_EDGE: For the explicit +thermal ALE coupling, allow the heat transfer through the shell edges +if _EDGE is added to *CONSTRAINED_LAGRANGE_IN_SOLID. + *CONSTRAINED_LAGRANGE_IN_SOLID: For the explicit thermal +solver, add work due to friction to the enthalpies of ALE and struc- +ture +with +*CONSTRAINED_LAGRANGE_IN_SOLID (CTYPE = 4). +elements +coupled + *CONTROL_EXPLICIT_THERMAL_INITIAL: Initialize the tempera- +tures for the explicit thermal solver. + *CONTROL_EXPLICIT_THERMAL_BOUNDARY: Control boundary +temperatures for the explicit thermal solver. + *CONTROL_EXPLICIT_THERMAL_OUTPUT: Output the tempera- +tures at element centers for the explicit thermal solver. + *DATABASE_PROFILE: For the explicit thermal solver, output tem- +perature profiles. +• Miscellaneous +INTRODUCTION +◦ *INITIAL_LAG_MAPPING: Implement a 3D to 3D lagrangian mapping +and map the nodal temperatures. +◦ *CONTROL_REFINE_SHELL and *CONTROL_REFINE_SOLID: Add a +parameter MASTERSET to call a set of nodes to flag element edges along +which new child nodes are constrained. +◦ *BOUNDARY_PRESCRIBED_MOTION_SET_SEGMENT: Add DOF = 12 +to apply velocities in local coordinate systems attached to segments. +◦ Fixed +bug +when +occurring +non-zero +*DAMPING_PART_STIFFNESS, +using +*PART_COMPOSITE, AND the MIDs referenced by the different integra- +tion points have different material types. Symptoms could include many +types of unexpected behavior or error termination, but in other cases it +could be harmless. +has +defined +a +AND +part +is +◦ *DAMPING_FREQUENCY_RANGE (including _DEFORM option): Im- +proved internal calculation of damping constants such that the level of +damping more accurately matches the user-input value across the whole of +the frequency range FLOW to FHIGH. As an example, for CDAMP = 0.01, +FLOW = 1 Hz and FHIGH = 30 Hz, the actual damping achieved by the +previous algorithm varied between 0.008 and 0.012 (different values at dif- +ferent frequencies between FLOW and FHIGH), i.e. there were errors of +up to 20% of the target CDAMP. With the new algorithm, the errors are +reduced to 1% of the target CDAMP. This change will lead to some small +differences in results compared to previous versions of LS-DYNA. Users +wishing to retain the old method for compatibility with previous work can +do this by setting IFLG (7th field on Card 1) to 1. +in +the +Part +included +◦ Fixed bug that could cause unpredictable symptoms if Nodal Rigid Bodies +by +were +or +*DAMPING_FREQUENCY_RANGE +*DAMPING_FREQUENCY_RANGE_DEFORM. Now, the _DEFORM op- +tion +Set while +*DAMPING_FREQUENCY_RANGE (non _DEFORM option) damps them. +◦ Fixed bug in *PART_COMPOSITE: if a layer had a very small thickness de- +fined, such as 1E-9 times the total thickness, that layer would be assigned a +weighting factor of 1 (it should be close to zero). +ignores NRBs +referenced +silently +Part +the +Set +in +◦ Fix errors in implementation of *DEFINE_FILTER type CHAIN. +◦ Fix for *INTERFACE_LINKING_LOCAL when LCID is used. During +keyword processing, the LCID value was not properly converted to inter- +nal numbering. +◦ Switch coordinates in keyword reader to double precision. +◦ Change "Warning" to "Error" for multiply defined materials, boxes, coordi- +nate systems, vectors, and orientation vectors. The check for duplicate sec- +tion IDs now includes the element type and remains a warning for now, +because SPH is still detected as a SOLID. Once that is straightened out, +this should be made an error. +INTRODUCTION +◦ Add "TIMESTEP" as a variable for *DEFINE_CURVE_FUNCTION. This +variable holds the current simulation time step. +◦ Fix +a +bug +in +*DEFORMABLE_TO_RIGID_AUTOMATIC. (Fields 3 to 8 are now ig- +nored.) +CODE = 5 +case +the +for +of +◦ Issue error message and terminate the simulation when illegal ACTION is +used for *DEFINE_TRANSFORM. +◦ Add option of POS6N for *DEFINE_TRANSFORM to define transfor- +mation with 3 reference nodes and 3 target nodes. +◦ Fix a bug that can occur when adaptive elements are defined in a file in- +cluded by *INCLUDE_TRANSFORM. +◦ Merge *DEFORMABLE_TO_RIGID_AUTOMATIC cards if they use the +same switch time. This dependency of results on the order of the cards +and also gives better performance. +◦ If *SET_PART_OPTION is used, a "group_file" will be created which can +be read into LS-Prepost (Model > Groups > Load) for easy visualization of +part sets. +◦ Forces on *RIGIDWALL_GEOMETRIC_CYLINDER can now be subdivid- +ed into sections for output to rwforc. This gives a better idea of the force +distribution along the length of the cylinder. See the variable NSEGS. +◦ Added +the +keywords +*DEFINE_PRESSURE_TUBE +and +*DATABASE_PRTUBE for simulating pressure tubes in pedestrian crash. +◦ Fix non-effective OPTIONs DBOX, DVOL, DSOLID, DSHELL, DTSHELL, +DSEG for *SET_SEGMENT_GENERAL to delete segments. +◦ Fix incorrect transformation of valdmp in *DAMPING_GLOBAL with +*INCLUDE_TRANSFORM. +◦ Make *SET_NODE_COLLECT work together with *NODE_SET_MERGE. +◦ Fixed bug in adaptivity for *INCLUDE_TRANSFORM if jobid is used. +◦ Bugfix: *INTERFACE_SSI with blank optional card is now read in correct- +ly. +MATERIAL MODELS +Some of the material models presently implemented are: +• elastic, +• orthotropic elastic, +• kinematic/isotropic plasticity [Krieg and Key 1976], +• thermoelastoplastic [Hallquist 1979], +• soil and crushable/non-crushable foam [Key 1974], +• linear viscoelastic [Key 1974], +INTRODUCTION +• Blatz-Ko rubber [Key 1974], +• high explosive burn, +• hydrodynamic without deviatoric stresses, +• elastoplastic hydrodynamic, +• temperature dependent elastoplastic [Steinberg and Guinan 1978], +• isotropic elastoplastic, +• isotropic elastoplastic with failure, +• soil and crushable foam with failure, +• Johnson/Cook plasticity model [Johnson and Cook 1983], +• pseudo TENSOR geological model [Sackett 1987], +• elastoplastic with fracture, +• power law isotropic plasticity, +• strain rate dependent plasticity, +• rigid, +• thermal orthotropic, +• composite damage model [Chang and Chang 1987a 1987b], +• thermal orthotropic with 12 curves, +• piecewise linear isotropic plasticity, +• inviscid, two invariant geologic cap [Sandler and Rubin 1979, Simo et al, 1988a +• 1988b], +• orthotropic crushable model, +• Mooney-Rivlin rubber, +• resultant plasticity, +• force limited resultant formulation, +• closed form update shell plasticity, +• Frazer-Nash rubber model, +• laminated glass model, +• fabric, +• unified creep plasticity, +• temperature and rate dependent plasticity, +• elastic with viscosity, +• anisotropic plasticity, +INTRODUCTION +• user defined, +• crushable cellular foams [Neilsen, Morgan, and Krieg 1987], +• urethane foam model with hysteresis, +and some more foam and rubber models, as well as many materials models for springs +and dampers. The hydrodynamic material models determine only the deviatoric +stresses. Pressure is determined by one of ten equations of state including: +• linear polynomial [Woodruff 1973], +• JWL high explosive [Dobratz 1981], +• Sack “Tuesday” high explosive [Woodruff 1973], +• Gruneisen [Woodruff 1973], +• ratio of polynomials [Woodruff 1973], +• linear polynomial with energy deposition, +• ignition and growth of reaction in HE [Lee and Tarver 1980, Cochran and Chan +1979], +• tabulated compaction, +• tabulated, +• TENSOR pore collapse [Burton et al. 1982]. +The ignition and growth EOS was adapted from KOVEC [Woodruff 1973]; the other +subroutines, programmed by the authors, are based in part on the cited references and +are nearly 100 percent vectorized. The forms of the first five equations of state are also +given in the KOVEC user’s manual and are retained in this manual. The high explosive +programmed burn model is described by Giroux [Simo et al. 1988]. +The orthotropic elastic and the rubber material subroutines use Green-St. Venant +strains to compute second Piola-Kirchhoff stresses, which transform to Cauchy stresses. +The Jaumann stress rate formulation is used with all other materials with the exception +of one plasticity model which uses the Green-Naghdi rate. +SPATIAL DISCRETIZATION + are presently available. Currently springs, dampers, beams, membranes, shells, bricks, +thick shells and seatbelt elements are included. +The first shell element in DYNA3D was that of Hughes and Liu [Hughes and Liu 1981a, +1981b, 1981c], implemented as described in [Hallquist et al. 1985, Hallquist and Benson +1986]. This element [designated as HL] was selected from among a substantial body of +shell element literature because the element formulation has several desirable qualities: +INTRODUCTION +Shells +Solids +Beams +Trusses +Springs +Lumped Masses +Damper + Elements in LS-DYNA. +Figure 1-1. + Three-dimensional plane stress +constitutive subroutines are implemented for the shell elements which +iteratively update the stress tensor such that the stress component normal to +the shell midsurface is zero. An iterative update is necessary to accurately +determine the normal strain component which is necessary to predict thinning. +One constitutive evaluation is made for each integration point through the +h ll thi k +• It is incrementally objective (rigid body rotations do not generate strains), +allowing for the treatment of finite strains that occur in many practical applica- +tions. +• It is compatible with brick elements, because the element is based on a degener- +ated brick element formulation. This compatibility allows many of the efficient +and effective techniques developed for the DYNA3D brick elements to be used +with this shell element; +• It includes finite transverse shear strains; +• A through-the-thickness thinning option is also +available. +All shells in our current LS-DYNA code must satisfy these desirable traits to at least +some extent to be useful in metalforming and crash simulations. +The major disadvantage of the HL element turned out to be cost related and, for this +reason, within a year of its implementation we looked at the Belytschko-Tsay [BT] shell +[Belytschko and Tsay 1981, 1983, 1984] as a more cost effective, but possibly less +accurate alternative. In the BT shell the geometry of the shell is assumed to be perfectly +flat, the local coordinate system originates at the first node of the connectivity, and the +INTRODUCTION +co-rotational stress update does not use the costly Jaumann stress rotation. With these +and other simplifications, a very cost effective shell was derived which today has +become perhaps the most widely used shell elements in both metalforming and crash +applications. Results generated by the BT shell usually compare favorably with those of +the more costly HL shell. Triangular shell elements are implemented, based on work by +Belytschko and co-workers [Belytschko and Marchertas 1974, Bazeley et al. 1965, +Belytschko et al. 1984], and are frequently used since collapsed quadrilateral shell +elements tend to lock and give very bad results. LS-DYNA automatically treats +collapsed quadrilateral shell elements as C0 triangular elements. +Since the Belytschko-Tsay element is based on a perfectly flat geometry, warpage is not +considered. Although this generally poses no major difficulties and provides for an +efficient element, incorrect results in the twisted beam problem and similar situations +are obtained where the nodal points of the elements used in the discretization are not +coplanar. The Hughes-Liu shell element considers non-planar geometries and gives +good results on the twisted beam. The effect of neglecting warpage in a typical +application cannot be predicted beforehand and may lead to less than accurate results, +but the latter is only speculation and is difficult to verify in practice. Obviously, it +would be better to use shells that consider warpage if the added costs are reasonable +and if this unknown effect is eliminated. Another shell published by Belytschko, Wong, +and Chiang [Belytschko, Wong, and Chiang 1989, 1992] proposes inexpensive +modifications to include the warping stiffness in the Belytschko-Tsay shell. An +improved transverse shear treatment also allows the element to pass the Kirchhoff +patch test. This element is now available in LS-DYNA. Also, two fully integrated shell +elements, based on the Hughes and Liu formulation, are available in LS-DYNA, but are +rather expensive. A much faster fully integrated element which is essentially a fully +integrated version of the Belytschko, Wong, and Chiang element, type 16, is a more +recent addition and is recommended if fully integrated elements are needed due to its +cost effectiveness. +Zero energy modes in the shell and solid elements are controlled by either an hourglass +viscosity or stiffness. Eight node thick shell elements are implemented and have been +found to perform well in many applications. All elements are nearly 100% vectorized. +All element classes can be included as parts of a rigid body. The rigid body formulation +is documented in [Benson and Hallquist 1986]. Rigid body point nodes, as well as +concentrated masses, springs and dashpots can be added to this rigid body. +Membrane elements can be either defined directly as shell elements with a membrane +formulation option or as shell elements with only one point for through thickness +integration. The latter choice includes transverse shear stiffness and may be +inappropriate. For airbag material a special fully integrated three and four node +membrane element is available. +INTRODUCTION +Two different beam types are available: a stress resultant beam and a beam with cross +section integration at one point along the axis. The cross section integration allows for a +more general definition of arbitrarily shaped cross sections taking into account material +nonlinearities. +Spring and damper elements can be translational or rotational. Many behavior options +can be defined, e.g., arbitrary nonlinear behavior including locking and separation. +Solid elements in LS-DYNA may be defined using from 4 to 8 nodes. The standard +elements are based on linear shape functions and use one point integration and +hourglass control. A selective-reduced integrated (called fully integrated) 8 node solid +element is available for situations when the hourglass control fails. Also, two additional +solid elements, a 4 noded tetrahedron and an 8 noded hexahedron, with nodal +rotational degrees of freedom, are implemented based on the idea of Allman [1984] to +replace the nodal midside translational degrees of freedom of the elements with +quadratic shape functions by corresponding nodal rotations at the corner nodes. The +latter elements, which do not need hourglass control, require many numerical +operations compared to the hourglass controlled elements and should be used at places +where the hourglass elements fail. However, it is well known that the elements using +more than one point integration are more sensitive to large distortions than one point +integrated elements. +The thick shell element is a shell element with only nodal translations for the eight +nodes. The assumptions of shell theory are included in a non-standard fashion. It also +uses hourglass control or selective-reduced integration. This element can be used in +place of any four node shell element. It is favorably used for shell-brick transitions, as +no additional constraint conditions are necessary. However, care has to be taken to +know in which direction the shell assumptions are made; therefore, the numbering of +the element is important. +Seatbelt elements can be separately defined to model seatbelt actions combined with +dummy models. Separate definitions of seatbelts, which are one-dimensional elements, +with accelerometers, sensors, pretensioners, retractors, and sliprings are possible. The +actions of the various seatbelt definitions can also be arbitrarily combined. +CONTACT-IMPACT INTERFACES +The three-dimensional contact-impact algorithm was originally an extension of the +NIKE2D [Hallquist 1979] two-dimensional algorithm. As currently implemented, one +surface of the interface is identified as a master surface and the other as a slave. Each +surface is defined by a set of three or four node quadrilateral segments, called master +and slave segments, on which the nodes of the slave and master surfaces, respectively, +must slide. In general, an input for the contact-impact algorithm requires that a list of +INTRODUCTION +master and slave segments be defined. For the single surface algorithm only the slave +surface is defined and each node in the surface is checked each time step to ensure that +it does not penetrate through the surface. Internal logic [Hallquist 1977, Hallquist et al. +1985] identifies a master segment for each slave node and a slave segment for each +master node and updates this information every time step as the slave and master +nodes slide along their respective surfaces. It must be noted that for general automatic +definitions only parts/materials or three-dimensional boxes have to be given. Then the +possible contacting outer surfaces are identified by the internal logic in LS-DYNA. +More than 20 types of interfaces can presently be defined including: +•sliding only for fluid/structure or gas/structure interfaces +•tied +•sliding, impact, friction +•single surface contact +•discrete nodes impacting surface +•discrete nodes tied to surface +•shell edge tied to shell surface +•nodes spot welded to surface +•tiebreak interface +•one way treatment of sliding, impact, friction +•box/material limited automatic contact for shells +•automatic contact for shells (no additional input required) +•automatic single surface with beams and arbitrary orientations +•surface to surface eroding contact +•node to surface eroding contact +•single surface eroding contact +•surface to surface symmetric constraint method [Taylor and Flanagan 1989] +•node to surface constraint method [Taylor and Flanagan 1989] +•rigid body to rigid body contact with arbitrary force/deflection curve +•rigid nodes to rigid body contact with arbitrary force/deflection curve +•edge-to-edge +•draw beads +Interface friction can be used with most interface types. The tied and sliding only +interface options are similar to the two-dimensional algorithm used in LS-DYNA2D +[Hallquist 1976, 1978, 1980]. Unlike the general option, the tied treatments are not +symmetric; therefore, the surface which is more coarsely zoned should be chosen as the +master surface. When using the one-way slide surface with rigid materials, the rigid +material should be chosen as the master surface. +For geometric contact entities, contact has to be separately defined. It must be noted +that for the contact of a rigid body with a flexible body, either the sliding interface +definitions as explained above or the geometric contact entity contact can be used. +INTRODUCTION +Currently, the geometric contact entity definition is recommended for metalforming +problems due to high accuracy and computational efficiency. +INTERFACE DEFINITIONS FOR COMPONENT ANALYSIS +Interface definitions for component analyses are used to define surfaces, nodal lines, or +nodal points (*INTERFACE_COMPONENTS) for which the displacement and velocity +time histories are saved at some user specified frequency (*CONTROL_OUTPUT). This +data may then used to drive interfaces (*INTERFACE_LINKING) in subsequent +analyses. This capability is especially useful for studying the detailed response of a +small member in a large structure. For the first analysis, the member of interest need +only be discretized sufficiently that the displacements and velocities on its boundaries +are reasonably accurate. After the first analysis is completed, the member can be finely +discretized and interfaces defined to correspond with the first analysis. Finally, the +second analysis is performed to obtain highly detailed information in the local region of +interest. +When starting the analysis, specify a name for the interface segment file using the +Z = parameter on the LS-DYNA command line. When starting the second analysis, the +name of the interface segment file (created in the first run) should be specified using the +L = parameter on the LS-DYNA command line. +the above procedure, multiple +levels of sub-modeling are easily +Following +accommodated. The interface file may contain a multitude of interface definitions so +that a single run of a full model can provide enough interface data for many component +analyses. The interface feature represents a powerful extension of LS-DYNA’s analysis +capability. +PRECISION +to machine precision +The explicit time integration algorithms used in LS-DYNA are in general much less +sensitive +finite element solution methods. +than other +Consequently, double precision is not generally required. The benefits of this are +greatly improved utilization of memory and disk. When problems have been found we +have usually been able to overcome them by reorganizing the algorithm or by +converting to double precision locally in the subroutine where the problem occurs. +Particularly sensitive problems (e.g. some buckling problems, which can be sensitive to +small imperfections) may require the fully double precision version, which is available +on all platforms. Very large problems requiring more than 2 billion words of memory +will also need to be run in double precision, due to the array indexing limitation of +single precision integers. +Getting Started +GETTING STARTED +DESCRIPTION OF KEYWORD INPUT +The keyword input provides a flexible and logically organized database that is simple +to understand. Similar functions are grouped together under the same keyword. For +example, under the keyword *ELEMENT are included solid, beam, shell elements, +spring elements, discrete dampers, seat belts, and lumped masses. Many keywords +have options that are identified as follows: “OPTIONS” and “{OPTIONS}”. The +difference is that “OPTIONS” requires that one of the options must be selected to +complete the keyword command. The option is included when {} are used +to further indicate that these particular options are not necessary to complete the +keyword. +LS-DYNA User’s Manual is alphabetically organized in logical sections of input data. +Each logical section relates to a particular input. There is a control section for resetting +LS-DYNA defaults, a material section for defining constitutive constants, an equation- +of-state section, an element section where element part identifiers and nodal +connectivities are defined, a section for defining parts, and so on. Nearly all model data +can be input in block form. For example, consider the following where two nodal +points with their respective coordinates and shell elements with their part identity and +nodal connectivity’s are defined: +$define two nodes +$ +*NODE +10101x y z +10201x y z +$ define two shell elements +$ +*ELEMENT_SHELL +10201pidn1n2n3n4 +10301pidn1n2n3n4 +Alternatively, acceptable input could also be of the form: +$ define one node +$ +*NODE +10101x y z +$ define one shell element +$ +*ELEMENT_SHELL +10201pidn1n2n3n4 +$ +$ define one more node +$ +*NODE +10201x y z +$ define one more shell element +$ +*ELEMENT_SHELL +10301pidn1n2n3n4 +Getting Started +*NODE +*ELEMENT +*PART +NID X Y Z +EID PID N1 N2 N3 N4 +PID SID MID EOSID HGID +*SECTION_SHELL +SID ELFORM SHRF NIP PROPT QR ICOMP +*MAT_ELASTIC +MID RO E PR DA DB +*EOS +*HOURGLASS +EOSID +HGID +Figure 2-1. Organization of the keyword input. +A data block begins with a keyword followed by the data pertaining to the keyword. +The next keyword encountered during the reading of the block data defines the end of +the block and the beginning of a new block. A keyword must be left justified with the +“*” contained in column one. A dollar sign “$” in column one precedes a comment and +causes the input line to be ignored. Data blocks are not a requirement for LS-DYNA but +they can be used to group nodes and elements for user convenience. Multiple blocks +can be defined with each keyword if desired as shown above. It would be possible to +put all nodal points definitions under one keyword *NODE, or to define one *NODE +keyword prior to each node definition. The entire LS-DYNA input is order +independent with the exception of the optional keyword, *END, which defines the end +of input stream. Without the *END termination is assumed to occur when an end-of- +file is encountered during the reading. +Figure 2-1 highlights how various entities relate to each other in LS-DYNA input. In +this figure the data included for the keyword, *ELEMENT, is the element identifier, +EID, the part identifier, PID, and the nodal points identifiers, the NID’s, defining the +element connectivity: N1, N2, N3, and N4. The nodal point identifiers are defined in the +*NODE section where each NID should be defined just once. A part defined with the +*PART keyword has a unique part identifier, PID, a section identifier, SID, a material or +constitutive model identifier, MID, an equation of state identifier, EOSID, and the +hourglass control identifier, HGID. The *SECTION keyword defines the section +identifier, SID, where a section has an element formulation specified, a shear factor, +SHRF, a numerical integration rule, NIP, among other parameters. +Constitutive constants are defined in the *MAT section where constitutive data is +defined for all element types including solids, beams, shells, thick shells, seat belts, +springs, and dampers. Equations of state, which are used only with certain *MAT +materials for solid elements, are defined in the *EOS section. Since many elements in +LS-DYNA use uniformly reduced numerical integration, zero energy deformation +modes may develop. These modes are controlled numerically by either an artificial +stiffness or viscosity which resists the formation of these undesirable modes. The +hourglass control can optionally be user specified using the input in the *HOURGLASS +section. +Getting Started +During the keyword input phase where data is read, only limited checking is performed +on the data since the data must first be counted for the array allocations and then +reordered. Considerably more checking is done during the second phase where the +input data is printed out. Since LS-DYNA has retained the option of reading older non- +keyword input files, we print out the data into the output file d3hsp (default name) as +in previous versions of LS-DYNA. An attempt is made to complete the input phase +before error terminating if errors are encountered in the input. Unfortunately, this is +not always possible and the code may terminate with an error message. The user +should always check either output file, d3hsp or messag, for the word “Error”. +The input data following each keyword can be input in free format. In the case of free +format input the data is separated by commas, i.e., +*NODE +10101,x ,y ,z +10201,x ,y ,z +*ELEMENT_SHELL +10201,pid,n1,n2,n3,n4 +10301,pid,n1,n2,n3,n4 +When using commas, the formats must not be violated. An I8 integer is limited to a +maximum positive value of 99999999, and larger numbers having more than eight +characters are unacceptable. The format of the input can change from free to fixed +anywhere in the input file. The input is case insensitive and keywords can be given in +either upper or lower case. The asterisks “*” preceding each keyword must be in column one. +To provide a better understanding behind the keyword philosophy and how the +options work, a brief review the keywords is given below. +*AIRBAG +The geometric definition of airbags and the thermodynamic properties for the airbag +inflator models can be made in this section. This capability is not necessarily limited to +the modeling of automotive airbags, but it can also be used for many other applications +such as tires and pneumatic dampers. +*ALE +This keyword provides a way of defining input data pertaining to the Arbitrary- +Lagrangian-Eulerian capability. +This section applies to various methods of specifying either fixed or prescribed +boundary conditions. For compatibility with older versions of LS-DYNA it is still +possible to specify some nodal boundary conditions in the *NODE card section. +*CASE +This keyword option provides a way of running multiple load cases sequentially. +Within each case, the input parameters, which include loads, boundary conditions, +control cards, contact definitions, initial conditions, etc., can change. If desired, the +results from a previous case can be used during initialization. Each case creates unique +file names for all output results files by appending CIDn to the default file name. +*COMPONENT +This section contains analytical rigid body dummies that can be placed within vehicle +and integrated implicitly. +*CONSTRAINED +This section applies constraints within the structure between structural parts. For +example, nodal rigid bodies, rivets, spot welds, linear constraints, tying a shell edge to a +shell edge with failure, merging rigid bodies, adding extra nodes to rigid bodies and +defining rigid body joints are all options in this section. +*CONTACT +This section is divided in to three main sections. The *CONTACT section allows the +user to define many different contact types. These contact options are primarily for +treating contact of deformable to deformable bodies, single surface contact in +deformable bodies, deformable body to rigid body contact, and tying deformable +structures with an option to release the tie based on plastic strain. The surface +definition for contact is made up of segments on the shell or solid element surfaces. The +keyword options and the corresponding numbers in previous code versions are: +STRUCTURED INPUT TYPE ID +KEYWORD NAME +1 +p 1 +2 +SLIDING_ONLY +SLIDING_ONLY_PENALTY +TIED_SURFACE_TO_SURFACE +3 +a 3 +4 +5 +a 5 +6 +7 +8 +9 +10 +a 10 +13 +a 13 +14 +15 +16 +17 +18 +19 +20 +21 +22 +23 +Getting Started +SURFACE_TO_SURFACE +AUTOMATIC_SURFACE_TO_SURFACE +SINGLE_SURFACE +NODES_TO_SURFACE +AUTOMATIC_NODES_TO_SURFACE +TIED_NODES_TO_SURFACE +TIED_SHELL_EDGE_TO_SURFACE +TIEBREAK_NODES_TO_SURFACE +TIEBREAK_SURFACE_TO_SURFACE +ONE_WAY_SURFACE_TO_SURFACE +AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE +AUTOMATIC_SINGLE_SURFACE +AIRBAG_SINGLE_SURFACE +ERODING_SURFACE_TO_SURFACE +ERODING_SINGLE_SURFACE +ERODING_NODES_TO_SURFACE +CONSTRAINT_SURFACE_TO_SURFACE +CONSTRAINT_NODES_TO_SURFACE +RIGID_BODY_TWO_WAY_TO_RIGID_BODY +RIGID_NODES_TO_RIGID_BODY +RIGID_BODY_ONE_WAY_TO_RIGID_BODY +SINGLE_EDGE +DRAWBEAD +Getting Started +The *CONTACT_ENTITY section treats contact between a rigid surface, usually defined +as an analytical surface, and a deformable structure. Applications of this type of contact +exist in the metal forming area where the punch and die surface geometries can be +input as VDA surfaces which are treated as rigid. Another application is treating +contact between rigid body occupant dummy hyper-ellipsoids and deformable +structures such as airbags and instrument panels. This option is particularly valuable in +coupling with the rigid body occupant modeling codes MADYMO and CAL3D. The +*CONTACT_1D is for modeling rebars in concrete structure. +*CONTROL +Options available in the *CONTROL section allow the resetting of default global +parameters such as the hourglass type, the contact penalty scale factor, shell element +formulation, numerical damping, and termination time. +*DAMPING +Defines damping either globally or by part identifier. +*DATABASE +This keyword with a combination of options can be used for controlling the output of +ASCII databases and binary files output by LS-DYNA. With this keyword the +frequency of writing the various databases can be determined. +*DEFINE +This section allows the user to define curves for loading, constitutive behaviors, etc.; +boxes to limit the geometric extent of certain inputs; local coordinate systems; vectors; +and orientation vectors specific to spring and damper elements. Items defined in this +section are referenced by their identifiers throughout the input. For example, a +coordinate system identifier is sometimes used on the *BOUNDARY cards, and load +curves are used on the *AIRBAG cards. +*DEFORMABLE_TO_RIGID +This section allows the user to switch parts that are defined as deformable to rigid at the +start of the analysis. This capability provides a cost efficient method for simulating +events such as rollover events. While the vehicle is rotating the computation cost can be +reduced significantly by switching deformable parts that are not expected to deform to +rigid parts. Just before the vehicle comes in contact with ground, the analysis can be +stopped and restarted with the part switched back to deformable. +Define identifiers and connectivities for all elements which include shells, beams, solids, +thick shells, springs, dampers, seat belts, and concentrated masses in LS-DYNA. +*EOS +This section reads the equations of state parameters. The equation of state identifier, +EOSID, points to the equation of state identifier on the *PART card. +*HOURGLASS +Defines hourglass and bulk viscosity properties. The identifier, HGID, on the +*HOURGLASS card refers to HGID on *PART card. +*INCLUDE +To make the input file easy to maintain, this keyword allows the input file to be split +into sub-files. Each sub-file can again be split into sub-sub-files and so on. This option +is beneficial when the input data deck is very large. +*INITIAL +Initial velocity and initial momentum for the structure can be specified in this section. +The initial velocity specification can be made by *INITIAL_VELOCITY_NODE card or +*INITIAL_VELOCITY cards. In the case of *INITIAL_VELOCITY_NODE nodal +identifiers are used to specify the velocity components for the node. Since all the nodes +in the system are initialized to zero, only the nodes with non-zero velocities need to be +specified. The *INITIAL_VELOCITY card provides the capability of being able to +specify velocities using the set concept or boxes. +*INTEGRATION +In this section the user defined integration rules for beam and shell elements are +specified. IRID refers to integration rule number IRID on *SECTION_BEAM and *SEC- +TION_SHELL cards respectively. Quadrature rules in the *SECTION_SHELL and +*SECTION_BEAM cards need to be specified as a negative number. The absolute value +of the negative number refers to user defined integration rule number. Positive rule +numbers refer to the built in quadrature rules within LS-DYNA. +Interface definitions are used to define surfaces, nodal lines, and nodal points for which +the displacement and velocity time histories are saved at some user specified frequency. +This data may then be used in subsequent analyses as an interface ID in the *INTER- +FACE_LINKING_DISCRETE_NODE as master nodes, in *INTERFACE_LINKING_- +SEGMENT as master segments and in *INTERFACE_LINKING_EDGE as the master +edge for a series of nodes. +This capability is especially useful for studying the detailed response of a small member +in a large structure. For the first analysis, the member of interest need only be +discretized sufficiently that the displacements and velocities on its boundaries are +reasonably accurate. After the first analysis is completed, the member can be finely +discretized in the region bounded by the interfaces. Finally, the second analysis is +performed to obtain highly detailed information in the local region of interest. +When beginning the first analysis, specify a name for the interface segment file using +the Z=parameter on the LS-DYNA execution line. When starting the second analysis, +the name of the interface segment file created in the first run should be specified using +the L=parameter on the LS-DYNA command line. Following the above procedure, +multiple levels of sub-modeling are easily accommodated. The interface file may +contain a multitude of interface definitions so that a single run of a full model can +provide enough interface data for many component analyses. The interface feature +represents a powerful extension of LS-DYNA’s analysis capabilities. A similar +capability using *INTERFACE_SSI may be used for soil-structure interaction analysis +under earthquake excitation. +*KEYWORD +Flags LS-DYNA that the input deck is a keyword deck. To have an effect this must be +the very first card in the input deck. Alternatively, by typing “keyword” on the execute +line, keyword input formats are assumed and the “*KEYWORD” is not required. If a +number is specified on this card after the word KEYWORD it defines the memory size +to used in words. The memory size can also be set on the command line. +NOTE: The memory specified on the execution line over- +rides memory specified on the *keyword card. +*LOAD +This section provides various methods of loading the structure with concentrated point +loads, distributed pressures, body force loads, and a variety of thermal loadings. +This section allows the definition of constitutive constants for all material models +available in LS-DYNA including springs, dampers, and seat belts. The material +identifier, MID, points to the MID on the *PART card. +*NODE +Define nodal point identifiers and their coordinates. +*PARAMETER +This option provides a way of specifying numerical values of parameter names that are +referenced throughout the input file. The parameter definitions, if used, should be +placed at the beginning of the input file following *KEYWORD. *PARAMETER_EX- +PRESSION permits general algebraic expressions to be used to set the values. +*PART +This keyword serves two purposes. +1. Relates part ID to *SECTION, *MATERIAL, *EOS and *HOURGLASS sections. +2. Optionally, in the case of a rigid material, rigid body inertia properties and +initial conditions can be specified. Deformable material repositioning data can +also be specified in this section if the reposition option is invoked on the *PART +card, i.e., *PART_REPOSITION. +*PERTURBATION +This keyword provides a way of defining deviations from the designed structure such +as, buckling imperfections. +*RAIL +This keyword provides a way of defining a wheel-rail contact algorithm intended for +railway applications but can also be used for other purposes. The wheel nodes (defined +on *RAIL_TRAIN) represent the contact patch between wheel and rail. +*RIGIDWALL +Rigid wall definitions have been divided into two separate sections, PLANAR and +GEOMETRIC. Planar walls can be either stationary or moving in translational motion +Getting Started +with mass and initial velocity. The planar wall can be either finite or infinite. +Geometric walls can be planar as well as have the geometric shapes such as rectangular +prism, cylindrical prism and sphere. By default, these walls are stationary unless the +option MOTION is invoked for either prescribed translational velocity or displacement. +Unlike the planar walls, the motion of the geometric wall is governed by a load curve. +Multiple geometric walls can be defined to model combinations of geometric shapes +available. For example, a wall defined with the CYLINDER option can be combined +with two walls defined with the SPHERICAL option to model hemispherical surface +caps on the two ends of a cylinder. Contact entities are also analytical surfaces but have +the significant advantage that the motion can be influenced by the contact to other +bodies, or prescribed with six full degrees-of-freedom. +*SECTION +In this section, the element formulation, integration rule, nodal thicknesses, and cross +sectional properties are defined. All section identifiers (SECID’s) defined in this section +must be unique, i.e., if a number is used as a section ID for a beam element then this +number cannot be used again as a section ID for a solid element. +*SENSOR +This keyword provides a convenient way of activating and deactivating boundary +conditions, airbags, discrete elements, +joints, contact, rigid walls, single point +constraints, and constrained nodes. The sensor capability is new in the second release +of version 971 and will evolve in later releases to encompass many more LS-DYNA +capabilities and replace some of the existing capabilities such as the airbag sensor logic. +*SET +A concept of grouping nodes, elements, materials, etc., in sets is employed throughout +the LS-DYNA input deck. Sets of data entities can be used for output. So-called slave +nodes used in contact definitions, slaves segment sets, master segment sets, pressure +segment sets and so on can also be defined. The keyword, *SET, can be defined in two +ways: +1. Option LIST requires a list of entities, eight entities per card, and define as +many cards as needed to define all the entities. +2. Option COLUMN, where applicable, requires an input of one entity per line +along with up to four attribute values which are used by other keywords to +specify, for example, the failure criterion input that is needed for *CONTACT_- +CONSTRAINT_NODES_TO_SURFACE. +This keyword provides an alternative way of stopping the calculation before the +termination time is reached. The termination time is specified on the *CONTROL_TER- +MINATION input and will terminate the calculation whether or not the options +available in this section are active. +*TITLE +In this section a title for the analysis is defined. +*USER_INTERFACE +This section provides a method to provide user control of some aspects of the contact +algorithms including friction coefficients via user defined subroutines. +RESTART +This section of the input is intended to allow the user to restart the simulation by +providing a restart file and optionally a restart input defining changes to the model +such as deleting contacts, materials, elements, switching materials from rigid to +deformable, deformable to rigid, etc. +*RIGID_DEFORMABLE +This section switches rigid parts back to deformable in a restart to continue the event of +a part impacting the ground which may have been modeled with a rigid wall. +*STRESS_INITIALIZATION +This is an option available for restart runs. In some cases there may be a need for the +user to add contacts, elements, etc., which are not available options for standard restart +runs. A full input containing the additions is needed if this option is invoked upon +restart. +Getting Started +SUMMARY OF COMMONLY USED OPTIONS +The following table gives a list of the commonly used keywords related by topic. +Topic +Component +Keywords +Nodes +Elements +Geometry +Discrete Elements +Part +Material +Materials +Sections +Discrete sections +*NODE +*ELEMENT_BEAM +*ELEMENT_SHELL +*ELEMENT_SOLID +*ELEMENT_TSHELL +*ELEMENT_DISCRETE +*ELEMENT_SEATBELT +*ELEMENT_MASS +PART cards glues the model together: +⎧*MAT +{{ +*SECTION +{{⎨ +*EOS +⎩ +*HOURGLASS +*PART → +*MAT +*SECTION_BEAM +*SECTION_SHELL +*SECTION_SOLID +*SECTION_TSHELL +*SECTION_DISCRETE +*SECTION_SEATBELT +Equation of state +*EOS +Hourglass +Contacts & +Rigid walls +Defaults for contacts +Definition of contacts +Definition of rigid walls +*CONTROL_HOURGLASS +*HOURGLASS +*CONTROL_CONTACT +*CONTACT_OPTION +*RIGIDWALL_OPTION +Topic +Component +Keywords +Getting Started +Boundary +Conditions & +Loadings +Constraints +and spot +welds +Output +Control +Restraints +Gravity (body) load +Point load +Pressure load +Thermal load +Load curves +Constrained nodes +Welds +Rivet +*NODE +*BOUNDARY_SPC_OPTION +*LOAD_BODY_OPTION +*LOAD_NODE_OPTION +*LOAD_SEGMENT_OPTION +*LOAD_SHELL_OPTION +*LOAD_THERMAL_OPTION +*DEFINE_CURVE +*CONSTRAINED_NODE_SET +*CONSTRAINED_GENERALIZED_WELD +*CONSTRAINED_SPOT_WELD +*CONSTRAINED_RIVET +Items in time history blocks +*DATABASE_HISTORY_OPTION +Default +ASCII time history files +*CONTROL_OUTPUT +*DATABASE_OPTION +Binary plot/time history/restart +files +*DATABASE_BINARY_OPTION +Nodal reaction output +*DATABASE_NODAL_FORCE_GROUP +Termination +Termination time +Termination cycle +CPU termination +Degree of freedom +*CONTROL_TERMINATION +*CONTROL_TERMINATION +*CONTROL_CPU +*TERMINATION_NODE +Table 2.1. Keywords for the most commonly used options. +EXECUTION SYNTAX +The execution line for LS-DYNA, sometimes referred to as the command line, is as +follows: +Getting Started +LS-DYNA I=inf O=otf G=ptf D3PART=d3part D=dpf F=thf T=tpf A=rrd +M=sif S=iff H=iff Z=isf1 L=isf2 B=rlf W=root E=efl X=scl C=cpu K=kill +V=vda Y=c3d BEM=bof {KEYWORD} {THERMAL} {COUPLE} {INIT} +{CASE} {PGPKEY} MEMORY=nwds MODULE=dll NCPU=ncpu PA- +RA=para +JOBID=jobid +D3PROP=d3prop GMINP=gminp GMOUT=gmout MCHECK=y +NCYCLE=ncycle +ENDTIME=time +where, +inf = +input file (user specified) +otf = high speed printer file (default = d3hsp) +ptf = binary plot file for postprocessing (default = d3plot) + d3part = binary plot file for subset of parts; see *DATABASE_BINARY_D3PART +(default = d3part) +dpf = dump file to write for purposes of restarting (default = d3dump). This file +is written at the end of every run and during the run as requested by +*DATABASE_BINARY_D3DUMP. To stop the generation of this dump +file, specify “d=nodump” (case insensitive). +thf = binary plot file for time histories of selected data (default = d3thdt) +tpf = optional temperature file +rrd = running restart dump file (default = runrsf) +sif = stress initialization file (user specified) +iff = +interface force file (user specified). See *DATBASE_BINARY_INTFOR +and *DATABASE_BINARY_FSIFOR. +isf1 = interface segment save file to be created (default = infmak) +isf2 = existing interface segment save file to be used (user specified) +rlf = binary plot file for dynamic relaxation (default = d3drfl) +efl = echo file containing optional input echo with or without node/element +data +root = root file name for general print option +scl = scale factor for binary file sizes (default =70) +cpu = cumulative cpu time limit in seconds for the entire simulation, including +all restarts, if cpu is positive. If cpu is negative, the absolute value of cpu +is the cpu time limit in seconds for the first run and for each subsequent +restart run. +kill = if LS-DYNA encounters this file name it will terminate with a restart file +(default = d3kil) +Getting Started +vda = VDA/IGES database for geometrical surfaces +c3d = CAL3D input file +bof = *FREQUENCY_DOMAIN_ACOUSTIC_BEM output file + nwds = Number of words to be allocated. On engineering workstations a word +isusually 32bits. This number overwrites the memory size specified on +the *KEYWORD card at the beginning of the input deck. +dll = The dynamic library for user subroutines. Only one dynamic library can +be loaded via “module=dll”. See *MODULE_LOAD command for load- +ing multiple dynamic libraries. + ncpu = Overrides NCPU and CONST defined in *CONTROL_PARALLEL. A +positive value sets CONST = 2 and a negative values sets CONST = 1. See +the *CONTROL_PARALLEL command for an explanation of these pa- +rameters. The *KEYWORD command provides an alternative way to set +the number of CPUs. +para = Overrides PARA defined in *CONTROL_PARALLEL. +time = Overrides ENDTIM defined in *CONTROL_TERMINATION. + ncycle = Overrides ENDCYC defined in *CONTROL_TERMINATION. +jobid = Character string which acts as a prefix for all output files. Maximum +length is 72 characters. Do not include the following characters: ) (* / ? \. + d3prop = See *DATABASE_BINARY_D3PROP input parameter IFILE for options. + gminp = Input file for reading recorded motions in *INTERFACE_SSI (default = +gmbin). + gmout = Output file for writing recorded motions in *INTERFACE_SSI_AUX +(default = gmbin). +In order to avoid undesirable or confusing results, each LS-DYNA run should be +performed in a separate directory, unless using the command line parameter “jobid” +described above. If rerunning a job in the same directory, old files should first be +removed or renamed to avoid confusion since the possibility exists that the binary +database may contain results from both the old and new run. +By including “keyword” anywhere on the execute line or instead if *KEYWORD is the +first card in the input file, the keyword formats are expected; otherwise, the older +structured input file will be expected. +To run a coupled thermal analysis the command “couple” must be in the execute line. +A thermal only analysis may be run by including the word “thermal” in the execution +line. +Getting Started +The execution line option “pgpkey” will output the current public PGP key used by LS- +DYNA for encryption of input. The public key and some instructions on how to use the +key are written to the screen as well as a file named “lstc_pgpkey.asc”. +The “init” (or sw1. can be used instead) command on the execution line causes the +calculation to run just one cycle followed by termination with a full restart file. No +editing of the input deck is required. The calculation can then be restarted with or +without any additional input. Sometimes this option can be used to reduce the memory +on restart if the required memory is given on the execution line and is specified too +large in the beginning when the amount of required memory is unknown. Generally, +this option would be used at the beginning of a new calculation. +If the word “case” appears on the command line, then *CASE statements will be +handled by the built in driver routines. Otherwise they should be processed by the +external “lscasedriver” program, and if any *CASE statements are encountered it will +cause an error. +If “mcheck=y” is given on the command line, the program switches to “model check” +mode. In this mode the program will run only 10 cycles – just enough to verify that the +model will start. For implicit problems, all initialization is performed, but execution +halts before the first cycle. If the network license is being used, the program will +attempt to check out a license under the program name “LS-DYNAMC” so as not to use +up one of the normal DYNA licenses. If this fails, a normal execution license will be +used. +If the word “memory” is found anywhere on the execution line and if it is not set via +“memory=nwds” LS-DYNA will give the default size of memory, request, and then +read in the desired memory size. This option is necessary if the default value is +insufficient memory and termination occurs as a result. Occasionally, the default value +is too large for execution and this option can be used to lower the default size. Memory +can also be specified on the *KEYWORD card. +SENSE SWITCH CONTROLS +The status of an in-progress LS-DYNA simulation can be determined by using the sense +switch. On UNIX versions, this is accomplished by first typing a “^C” (Control-C). +This sends an interrupt to LS-DYNA which is trapped and the user is prompted to +input the sense switch code. LS-DYNA has nine terminal sense switch controls that are +tabulated below: +Response +A restart file is written and LS-DYNA terminates. +Type +SW1. +Getting Started +Type +SW2. +SW3. +SW4. +SW5. +SW7. +SW8. +SW9. +SWA. +lprint +Response +LS-DYNA responds with time and cycle numbers. +A restart file is written and LS-DYNA continues. +A plot state is written and LS-DYNA continues. +Enter interactive graphics phase and real time visualization. +Turn off real time visualization. +Interactive 2D rezoner +visualization. +for solid elements and real +time +Turn off real time visualization (for option SW8). +Flush ASCII file buffers. +Enable/Disable printing of equation solver memory, cpu +requirements. +nlprint +Enable/Disable printing of nonlinear equilibrium +information. +iteration +iter +conv +stop +Enable/Disable output of binary plot database "d3iter" showing +mesh after each equilibrium iteration. Useful for debugging +convergence problems. +Temporarily override nonlinear convergence tolerances. +Halt execution immediately, closing open files. +On UNIX/LINUX and Windows systems the sense switches can still be used if the job is +running in the background or in batch mode. To interrupt LS-DYNA simply create a +file called d3kil containing the desired sense switch, e.g., "sw1." LS-DYNA periodically +looks for this file and if found, the sense switch contained therein is invoked and the +d3kil file is deleted. A null d3kil file is equivalent to a "sw1." +When LS-DYNA terminates, all scratch files are destroyed: the restart file, plot files, and +high-speed printer files remain on disk. Of these, only the restart file is needed to +continue the interrupted analysis. +Getting Started +PROCEDURE FOR LS-DYNA/MPP +As described above the serial/SMP code supports the use of the SIGINT signal (usually +Ctrl-C) to interrupt the execution and prompt the user for a "sense switch." The MPP +code also supports this capability. However, on many systems a shell script or front +end program (generally "mpirun") is required to start MPI applications. Pressing Ctrl-C +on some systems will kill this process, and thus kill the running MPP-DYNA +executable. On UNIX/LINUX systems, as workaround, when the MPP code begins +execution it creates a file named, “bg_switch”, in the current working directory. This +file contains the following single line: +rsh kill -INT +where is the hostname of the machine on which the root MPP-DYNA +process is running, and is its process id. (on HP systems, "rsh" is replaced by +"remsh"). Thus, simply executing this file will send the appropriate signal. For +Windows, usually the D3KIL file is used to interrupt the execution. +For more information about running the LS-DYNA/MPP Version see Appendix O. +Input +Stress Initialization +Restart +Interface Segment +VDA Geometry +I= += +R= +L= +V = += +Thermal File += +CAL3D Input +Getting Started +Files: Input and Output +Restart Files +D=d3dump +A=runrsf +Z= +Restart Dump +Running Dump +Interface Segment +LS-DYNA +Binary Output +G=d3plot +F=d3dht +S= +B=d3drfl +"d3plot" +Time History +Interface Force +Dynamic Relaxation +O=d3hsp +E= +Text Output +Printer File +"messag" +Input Echo +Others... +Figure 2-2. Files Input and Output. +1. Uniqueness. File names must be unique. +FILES +2. +Interface forces. The interface force file is created only if it is specified on the +execution line “S=iff”. +3. File size limits. For very large models, the default size limits for binary output +files may not be large enough for a single file to hold even a single plot state, in +Getting Started +which case the file size limit may be increased by specifying “X=scl" on the +execution line. The default file size limit (X=70) is 70 times one-million octal +words or 18.35 Mwords. That translates into 73.4 Mbytes (for 32-bit output) or +146.8 Mbytes (for 64-bit output). +4. CPU limits. Using “C=cpu” defines the maximum CPU usage allowed. When +the CPU usage limit is exceeded LS-DYNA will terminate with a restart file. +During a restart, cpu should be set to the total CPU used up to the current +restart plus whatever amount of additional time is wanted. +5. File usage in restart. When restarting from a dump file, the execution line +becomes +LS-DYNA I=inf O=otf G=ptf D=dpf R=rtf F=thf T=tpf A=rrd S=iff Z=isf1 +L=isf2 B=rlf W=root E=efl X=scl C=cpu K=kill Q=option KEYWORD +MEMORY=nwds +where, +rtf=[name of dump file written by LS-DYNA] +The root names of the dump files written by LS-DYNA = are controlled by dpf +(default = d3dump) and rrd (default = runrsf). A two-digit number follows the +root name, e.g., d3dump01, d3dump02, etc., to distinguish one dump file from +another. Typically, each dump file corresponds to a different simulation time. +The adaptive dump files contain all information required to successfully restart +so that no other files are needed except when CAD surface data is used. When +restarting a problem that uses VDA/IGES surface data, the vda input file must +be specified, e.g.: +LS-DYNA R=d3dump01 V=vda +If the data from the last run is to be remapped onto a new mesh, then specify: +“Q=remap”. The remap file is the dump file from which the remapping data is +taken. The remap option is available in SMP for brick elements only, MPP does +not support this option currently. +No stress initialization is possible at restart. Also the VDA files and the CAL3D files +must not be changed. +6. Default file names. File name dropouts are permitted; for example, the +following execution lines are acceptable: +LS-DYNA I=inf +and +Getting Started +LS-DYNA R=rtf +7. +Interface segments. For an analysis using interface segments, the execution +line in the first analysis is given by: +and in the second by: +LS-DYNA I=inf Z=isf1 +LS-DYNA I=inf L=isf1 +8. Batch execution. In some installations (e.g., GM) calculations are controlled +by a file called “names” on unit 88. The names files consists of two lines in +which the second line is blank. The first line of names contains the execution +line, for instance: +For a restart the execution line becomes: +I=inf +I=inf R=rtf +RESTART ANALYSIS +The LS-DYNA restart capability allows analyses to be broken down into stages. After +the completion of each stage in the calculation a “restart dump” is written that contains +all information necessary to continue the analysis. The size of this “dump” file is +roughly the same size as the memory required for the calculation. Results can be +checked at each stage by post-processing the output databases in the normal way, so the +chance of wasting computer time on incorrect analyses is reduced. +The restart capability is frequently used to modify models by deleting excessively +distorted elements, materials that are no longer important, and contact surfaces that are +no longer needed. Output frequencies of the various databases can also be altered. +Often, these simple modifications permit a calculation that might otherwise not to +continue on to a successful completion. Restarting can also help to diagnose why a +model is giving problems. By restarting from a dump that is written before the +occurrence of a numerical problem and obtaining output at more frequent intervals, it is +often possible to identify where the first symptoms appear and what aspect of the +model is causing them. +The format of the restart input file is described in this manual. If, for example, the user +wishes to restart the analysis from dump state nn, contained in file D3DUMPnn, then +the following procedure is followed: +Getting Started +1. Create the restart input deck, if required, as described in the Restart Section of +this manual. Call this file restartinput. +2. Start dyna from the command line by invoking: +LS-DYNA I=restartinput R=D3DUMPnn +3. +If no alterations to the model are made, then the execution line: +LS-DYNA R=D3DUMPnn +will suffice. Of course, the other output files should be assigned names from +the command line if the defaults have been changed in the original run. +The full deck restart option allows the user to begin a new analysis, with deformed +shapes and stresses carried forward from a previous analysis for selected materials. +The new analysis can be different from the original, e.g., more contact surfaces, different +geometry (of parts which are not carried forward), etc. Examples of applications +include: +• Crash analysis continued with extra contact surfaces; +• Sheet metalforming continued with different tools for modeling a multi-stage +forming process. +A typical restart file scenario: +Dyna is run using an input file named “job1.inf”, and a restart dump named +“d3dump01” is created. A new input file, “job2.inf”, is generated and submitted as a +restart with, “R=d3dump01”, as the dump file. The input file job2.inf contains the +entire model in its original undeformed state but with more contact surfaces, new output +databases, and so on. +Since this is a restart job, information must be given to tell LS-DYNA which parts of the +model should be initialized in the full deck restart. When the calculation begins the +restart database contained in the file d3dump01 is read, and a new database is created +to initialize the model in the input file, job2.inf. The data in file job2.inf is read and the +LS-DYNA proceeds through the entire input deck and initialization. At the end of the +initialization process, all the parts selected are initialized from the data saved from +d3dump01. This means that the deformed position and velocities of the nodes on the +elements of each part, and the stresses and strains in the elements (and, if the material +of the part is rigid, the rigid body properties) will be assigned. +It is assumed during this process that any initialized part has the same elements, in the +same order, with the same topology, in job1 and job2. If this is not the case, the parts +cannot be initialized. However, the parts may have different identifying numbers. +Getting Started +For discrete elements and seat belts, the choice is all or nothing. All discrete and belt +elements, retractors, sliprings, pretensioners and sensors must exist in both files and +will be initialized. +Materials which are not initialized will have no initial deformations or stresses. +However, if initialized and non-initialized materials have nodes in common, the nodes +will be moved by the initialized material causing a sudden strain in the non-initialized +material. This effect can give rise to sudden spikes in loading. +Points to note are: +• Time and output intervals are continuous with job1, i.e., the time is not reset to +zero. +• Don’t try to use the restart part of the input to change anything since this will be +overwritten by the new input file. +• Usually, the complete input file part of job2.inf will be copied from job1.inf, with +the required alterations. We again mention that there is no need to update the +nodal coordinates since the deformed shapes of the initialized materials will be +carried forward from job1. +• Completely new databases will be generated with the time offset. +VDA/IGES DATABASES +VDA surfaces are surfaces of geometric entities which are given in the form of +polynomials. The format of these surfaces is as defined by the German automobile and +supplier industry in the VDA guidelines, [VDA 1987]. +The advantage of using VDA surfaces is twofold. First, the problem of meshing the +surface of the geometric entities is avoided and, second, smooth surfaces can be +achieved which are very important in metalforming. With smooth surfaces, artificial +friction introduced by standard faceted meshes with corners and edges can be avoided. +This is a big advantage in springback calculations. +A very simple and general handling of VDA surfaces is possible allowing arbitrary +motion and generation of surfaces. For a detailed description, see Appendix L. +Getting Started +ASCII +Databases +Plot Files: +d3plot +d3thdt +Geometry: +i= +iges: +v= +vda: +Project: p= +Keyword: k= +Command: c= +Database: d= +LS-PrePost +Nastran: n= +Graphic Output +Fringe Plots +Time History +Animations +Keyword +Files +Project File +(*.proj) +Command File: +cfile +Database File: +post.db +Figure 2-3. File Organization +LS-PrePost® +LS-DYNA is designed to operate with a variety of commercial pre- and post-processing +packages. Currently, direct support is available from TRUEGRID, PATRAN, eta/VPG, +HYPERMESH, EASi-CRASH DYNA and FEMAP. Several third-party translation +programs are available for PATRAN and IDEAS. +Alternately, the pre- and post-processor LS-PrePost is available from LSTC and is +specialized for LS-DYNA. LS-PrePost is an advanced pre- and post-processor that is +delivered free with LS-DYNA. The user interface is designed to be both efficient and +intuitive. LS-PrePost runs on Windows, Linux, and Unix, utilizing OpenGL graphics to +achieve fast model rendering and XY plotting. +Some of the capabilities available in LS-PrePost are: +• Complete support for all LS-DYNA keyword data. +• Importing and combining multiple models from many sources (LS-DYNA +keyword, IDEAS neutral file, NASTRAN bulk data, STL ASCII, and STL binary +formats). +• Improved renumbering of model entities. +• Model Manipulation: Translate, Rotate, Scale, Project, Offset, Reflect +Getting Started +• LS-DYNA Entity Creation: Coordinate Systems, Sets, Parts, Masses, CNRBs, +Boxes, Spot welds, SPCs, Rigidwalls, Rivets, Initial Velocity, Accelerometers, +Cross Sections, etc. +• Mesh Generation: 2Dmesh Sketchboard, nLine Meshing, Line sweep into shell, +Shell sweep into solid, Tet-Meshing, Automatic surface meshing of IGES and +VDA data, Meshing of simple geometric objects (Plate, Sphere, Cylinder) +• Special Applications: Airbag folding, Dummy positioning, Seatbelt fitting, Initial +penetration check, Spot weld generation using MAT_100 +• Complete support of LS-DYNA results data file: d3plot file, d3thdt file, All +ASCII time history data file, Interface force file +LS-PrePost processes output from LS-DYNA. LS-PrePost reads the binary plot-files +generated by LS-DYNA and plots contours, fringes, time histories, and deformed +shapes. Color contours and fringes of a large number of quantities may be interactively +plotted on meshes consisting of plate, shell, and solid type elements. LS-PrePost can +compute a variety of strain measures, reaction forces along constrained boundaries. +LS-DYNA generates three binary databases. One contains information for complete +states at infrequent intervals; 50 to 100 states of this sort is typical in a LS-DYNA +calculation. The second contains information for a subset of nodes and elements at +frequent intervals; 1000 to 10,000 states is typical. The third contains interface data for +contact surfaces. +Getting Started + 24 + 20 + 16 + 12 + 8 + 4 + 0 +20.01 +8.84 +1.07 +1.25 +1.28 +1.49 +2.45 +2.80 +BT +BTW BL +BWC CHL HL +FBT CFHL FHL +Element type +Figure 2-4. Relative cost of the four noded shells available in LS-DYNA +where BT is the Belytschko-Tsay shell, BTW is the Belytschko-Tsay shell with +the warping stiffness taken from the Belytschko-Wong-Chiang, BWC, shell. +The BL shell is the Belytschko-Leviathan shell. CHL denotes the Hughes-Liu +shell, HL, with one point quadrature and a co-rotational formulation. FBT is a +Belytschko-Tsay like shell with full integration, FHL is the fully integrated +Hughes-Liu shell, and the CFHL shell is its co-rotational version. +EXECUTION SPEEDS +The relative execution speeds for various elements in LS-DYNA are tabulated below: +Element Type +Relative Cost +8 node solid with 1 point integration and default +hourglass control +as above but with Flanagan-Belytschko hourglass control +constant stress and Flanagan-Belytschko hourglass +control, i.e., the Flanagan-Belytschko element +4 node Belytschko-Tsay shell with four thickness +integration points +4 node Belytschko-Tsay shell with resultant plasticity +4 +5 +7 +4 +Element Type +Relative Cost +Getting Started +BCIZ triangular shell with four thickness integration +points +Co triangular shell with four thickness integration points +2 node Hughes-Liu beam with four integration points +2 node Belytschko-Schwer beam +2 node simple truss elements +7 +4 +9 +2 +1 +8 node solid-shell with four thickness integration points +11 +These relative timings are very approximate. Each interface node of the sliding +interfaces is roughly equivalent to one-half zone cycle in cost. Figure 2-4. illustrates the +relative cost of the various shell formulations in LS-DYNA. +UNITS +The units in LS-DYNA must be consistent. One way of testing whether a set of units is +consistent is to check that: +[force unit] = [mass unit] × [acceleration unit] +and that +[acceleration unit] = +[length unit] +[time unit]2 . +Examples of sets of consistent units are tabulated below. For a more comprehensive +table, see http://ftp.lstc.com/anonymous/outgoing/support/FAQ/consistent_units . +(a) +(b) +(c) +Length unit +Time unit +Mass unit +Force unit +Young’s Modulus of Steel +Density of Steel +Yield stress of Mild Steel +Acceleration due to gravity +Velocity equivalent to 30 mph +meter +second +kilogram +Newton +210.0E+09 +7.85E+03 +200.0E+06 +9.81 +13.4 +millimeter +second +tonne +Newton +210.0E+03 +7.85E–09 +200.0 +9.81E+03 +13.4E+03 +millimeter +millisecond +kilogram +kiloNewton +210.0 +7.85E–06 +0.200 +9.81E-03 +13.4 +Getting Started +GENERAL CARD FORMAT +The following sections specify, for each keyword command, the cards that must be +defined and those cards that are optional. Each card is described in its fixed format +form and is shown as a number of fields in an 80 character string. With the exception of +“long format input” as described later in this section, most cards are 8 fields with a field +length of 10 characters. A sample card is shown below. The card format is clearly +stated when it is different than 8 fields of 10 characters. +As an alternative to fixed format, a card may be in free format with the values of the +variables separated by commas. When using comma-delimited values on a card, the +number of characters used to specify a value must not exceed the field length for fixed +format. For example, an I8 number is limited to a value of 99999999 and a larger +number with more than 8 characters is unacceptable. A further restriction is that +characters beyond column 80 of each line are ignored by the code. Fixed format and +free, comma-delimited format can be mixed throughout the deck and even within +different cards of a single command but not within a card. +The limits on number of characters per variable and number of characters per line as +stated above are raised in the case of long format input. See the description of long +format input below. +Example Card. + Card [N] +1 +2 +Variable +NSID +PSID +Type +I +I +3 +A1 +F +4 +A2 +F +Default +none +none +1.0 +1.0 +Remarks +1 +2 +5 +A3 +F +0 +6 +KAT +I +1 +3 +7 +8 +In the example shown above, the row labeled “Type” gives the variable type and is +either F, for floating point or I, for an integer. The row labeled “Default” reveals the +default value set for a variable if zero is specified, the field is left blank, or the card is +not defined. The “Remarks” row refers to enumerated remarks at the end of the +section. +Getting Started +Optional Cards: +Each keyword card (line beginning with “*”) is followed by a set of data cards. Data +cards are either, +1. Required Cards. Unless otherwise indicated, cards are required. +2. Conditional Cards. Conditional cards are required provided some condition is +satisfied. The following is a typical conditional card: +ID Card. Additional card for the ID keyword option. +ID +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ABID +Type +I +HEADING +A70 +3. Optional Cards. An optional card is one that may be replaced by the next +keyword card. The fields in the omitted optional data cards are assigned their +default values. +Example. Suppose the data set for *KEYWORD consists of 2 required cards +and 3 optional cards. Then, the fourth card may be replaced by the next key- +word card. All the fields in the omitted fourth and fifth cards are assigned their +default values. +WARNING: In this example, even though the fourth card is optional, +the input deck may not jump from the third to fifth card. +The only card that card 4 may be replaced with is the next +keyword card. +Long Format Input: +To accommodate larger or more precise values for input variables than are allowed by +the standard format input as described above, a “long format” input option is available. +One way of invoking long format keyword input is by adding “long=y” to the +execution line. A second way is to add “long=y” to the *KEYWORD command in the +input deck. +long=y: read long keyword input deck; write long structured input deck. +long=s: read standard keyword input deck; write long structured input deck. +long=k: read long keyword input deck; write standard structured input deck. +Getting Started +The “long=s” option may be helpful in the rare event that the keyword input is of +standard format but LS-DYNA reports an input error and the dyna.str file reveals that one of more variables is incorrectly written to +dyna.str as a series of asterisks due to inadequate field length(s) in dyna.str. +The “long=k” option really serves no practical purpose. +When long format is invoked for keyword input, field lengths for each variable become +20 characters long (160 character limit per line for 8 variables; 200 character limit per +line for 10 variables). In this way, the number of input lines in long format is +unchanged from regular format. +To convert a standard format input deck to a long format input deck, run LS-DYNA +with “newformat = long” on the execution line. For example, if standard.k is a standard +format input deck, +ls-dyna i = standard.k newformat = long +will create a long format input deck called standard.k.long. +You can mix long and standard format within one input deck by use of “+” or “-“ signs +within the deck. If the execution line indicates standard format, you can add “ +” at the +end of any keywords to invoke long format just for those keywords. For example, +“*NODE +” in place of “*NODE” invokes a read format of two lines per node (I20, +3E20.0 on the first line and 2F20.0 on the second line). +Similarly, if the execution line indicates long format, you can add “-” at the end of any +keywords to invoke standard format for those keywords. For example, “*NODE –” in +place of “*NODE” invokes the standard read format of one line per node (I8, 3E16.0, +2F8.0). +Taking this idea a step further, adding a “-” or “+” to the end of the *INCLUDE +keyword command signals to LS-DYNA that all the commands in the included file are +standard format or long format, respectively. +Purpose: Define an airbag or control volume. +The keyword *AIRBAG provides a way of defining thermodynamic behavior of the gas +flow into the airbag as well as a reference configuration for the fully inflated bag. The +keyword cards in this section are defined in alphabetical order: +*AIRBAG_OPTION1_{OPTION2}_{OPTION3}_{OPTION4} +*AIRBAG_ADVANCED_ALE +*AIRBAG_ALE +*AIRBAG_INTERACTION +*AIRBAG_PARTICLE +*AIRBAG_REFERENCE_GEOMETRY_OPTION_OPTION +*AIRBAG_SHELL_REFERENCE_GEOMETRY +*AIRBAG_OPTION1_{OPTION2}_{OPTION3}_{OPTION4} +OPTION1 specifies one of the following thermodynamic models: +SIMPLE_PRESSURE_VOLUME +SIMPLE_AIRBAG_MODEL +ADIABATIC_GAS_MODEL +WANG_NEFSKE +WANG_NEFSKE_JETTING +WANG_NEFSKE_MULTIPLE_JETTING +LOAD_CURVE +LINEAR_FLUID +HYBRID +HYBRID_JETTING +HYBRID_CHEMKIN +FLUID_AND_GAS +OPTION2 specifies that an additional line of data is read for the WANG_NEFSKE type +thermodynamic relationships. The additional data controls the initiation of exit flow +from the airbag. OPTION2 takes the single option: +POP +OPTION3 specifies that a constant momentum formulation is used to calculate the +jetting load on the airbag an additional line of data is read in: OPTION3 takes the single +option: +CM +OPTION4 given by: +ID +Specifies that an airbag ID and heading information will be the first card of the airbag +definition. This ID is a unique number that is necessary for the identification of the +airbags in the definition of airbag interaction via *AIRBAG_INTERACTION keyword. +The numeric ID's and heading are written into the abstat and d3hsp files. +Core Cards: Common to all airbags +ID Card. Additional card for the ID keyword option. To use the *AIRBAG_INTERAC- +TION keyword ID Cards are required. +ID +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ABID +Type +I +HEADING +A70 + Card 1a +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SID +SIDTYP +RBID +VSCA +PSCA +VINI +MWD +SPSF +Type +I +Default +none +I +0 +I +0 +F +1. +F +1. +F +0. +F +0. +F +0. +Remark +optional + VARIABLE +DESCRIPTION +ABID +Airbag ID. This must be a unique number. +HEADING +Airbag descriptor. It is suggested that unique descriptions be +used. +SID +Set ID +SIDTYP +Set type: +EQ.0: segment, +NE.0: part set ID. +DESCRIPTION +*AIRBAG +RBID +Rigid body part ID for user defined activation subroutine: +LT.0: -RBID is taken as the rigid body part ID. Built in sensor +subroutine initiates the inflator. Load curves are offset +by initiation time. +EQ.0: The control volume is active from time zero. +GT.0: RBID is taken as the rigid body part ID. User sensor +subroutine initiates the inflator. Load curves are offset +by initiation time. See Appendix D. +Volume scale factor (default = 1.0) +Pressure scale factor (default = 1.0) +Initial filled volume +Mass weighted damping factor, D +Stagnation pressure scale factor, 0 <= 𝛾 <= 1 +VSCA +PSCA +VINI +MWD +SPSF +Remarks: +The first card is necessary for all airbag options. The option dependent cards follow. +Lumped parameter control volumes are a mechanism for determining volumes of +closed surfaces and applying a pressure based on some thermodynamic relation. The +volume is specified by a list of polygons similar to the pressure boundary condition +cards or by specifying a material subset which represents shell elements which form the +closed boundary. All polygon normal vectors must be oriented to face outwards from +the control volume, however for *AIRBAG_PARTICLE, which does not rely on control +volumes, all polygon normal vectors must be oriented to face inwards to get proper +volume . If holes are detected, they are +assumed to be covered by planar surfaces. +There are two sets of volume and pressure variables used for each control volume +model. First, the finite element model computes a volume 𝑉femodel and applies a +pressure 𝑃femodel. The thermodynamics of a control volume may be computed in a +different unit system with its own set of varriables: 𝑉cvolume and pressure 𝑃cvolume +which are used for integrating the differential equations for the control volume. The +conversion is as follows: +𝑉cvolume = (VSCA × 𝑉femodel) − VINI +𝑃femodel = PSCA×𝑃cvolume +Where VSCA, PSCA, and VINI are input parameters. Damping can be applied to the +structure enclosing a control volume by using a mass weighted damping formula: +𝑑 = 𝑚𝑖𝐷(𝑣𝑖 − 𝑣cg) +𝐹𝑖 +𝑑 is the damping force, mi is the nodal mass, 𝜈𝑖 is the velocity for a node, 𝑣cg is +where 𝐹𝑖 +the mass weighted average velocity of the structure enclosing the control volume, and +D is the damping factor. +An alternative, separate damping is based on the stagnation pressure. The stagnation +pressure is roughly the maximum pressure on a flat plate oriented normal to a steady +state flow field. The stagnation pressure is defined as 𝑝 = 𝛾𝜌𝑉2 where 𝑉 is the normal +velocity of the control volume relative to the ambient velocity, 𝜌 is the ambient air +density, and 𝛾 is a factor which varies from 0 to 1 and has to be chosen by the user. +Small values are recommended to avoid excessive damping. +Sensor input: +The sensor is mounted on a rigid body which is attached to the structure. The motion of +the sensor is evaluated in the local coordinate system of the rigid body. See *MAT_RIGID. This +local system rotates and translates with the rigid material. The default local system for +a rigid body is taken as the principal axes of the inertia tensor. +When the user defined criterion for airbag deployment is satisfied, a flag is set and +deployment begins. All load curves relating to the mass flow rate versus time are then +shifted by the initiation time. +RBID = 0: No rigid body +For this case there is no rigid body, and the control volume is active from time zero. +There are no additional sensor cards. +RBID > 0: User supplied sensor subroutine +The value of RBID is taken as a rigid body part ID, and a user supplied sensor +subroutine will be called to determine the flag that initiates deployment. See Appendix +D for details regarding the user supplied subroutine. For RBID > 0 the additional cards +are specified below: +User Subroutine Control Card. This card is read in when RBID > 0. +2 +3 +4 +5 +6 +7 +8 + Card 1b +Variable +Type +1 +N +I +Default +none +User Subroutine Constant Cards. Define N constants for the user subroutine. +Include only the number of cards necessary, i.e. for nine constants use 2 cards. + Card 1c +Variable +1 +C1 +Type +F +Default +0. +2 +C2 +F +0. +3 +C3 +F +0. +4 +C4 +F +0. +5 +C5 +F +0. +6 +7 +8 + VARIABLE +DESCRIPTION +N +Number of input parameters (not to exceed 25). +C1, …, CN +Up to 25 constants for the user subroutine. +RBID < 0: User supplied sensor subroutine +The value of –RBID is taken as rigid body part ID and a built in sensor subroutine is +called. For RBID < 0 there are three additional cards. +Acceleration Sensor Card. + Card 1d +Variable +1 +AX +Type +F +Default +0. +2 +AY +F +0. +3 +AZ +F +0. +Velocity Sensor Card. +4 +5 +6 +7 +8 +AMAG +TDUR +F +0. +F +0. + Card 1e +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DVX +DVY +DVZ +DVMAG +Type +F +Default +0. +F +0. +Displacement Sensor Card. + Card 1f +Variable +1 +UX +Type +F +Default +0. +2 +UY +F +0. +F +0. +3 +UZ +F +0. +F +0. +4 +5 +6 +7 +8 +UMAG +F +0. +AX +AY +AZ +*AIRBAG +DESCRIPTION +Acceleration level in local 𝑥-direction to activate inflator. The +absolute value of the 𝑥-acceleration is used. +EQ.0: inactive. +Acceleration level in local 𝑦-direction to activate inflator. The +absolute value of the 𝑦-acceleration is used. +EQ.0: inactive. +Acceleration level in local 𝑧-direction to activate inflator. The +absolute value of the 𝑧-acceleration is used. +EQ.0: inactive. +AMAG +Acceleration magnitude required to activate inflator. +EQ.0: inactive. +TDUR +DVX +DVY +DVZ +Time duration acceleration must be exceeded before the inflator +activates. This is the cumulative time from the beginning of the +calculation, i.e., it is not continuous. +Velocity change in local 𝑥-direction to activate the inflator. (The +absolute value of the velocity change is used.) +EQ.0: inactive. +Velocity change in local 𝑦-direction to activate the inflator. (The +absolute value of the velocity change is used.) +EQ.0: inactive. +Velocity change in local 𝑧-direction to activate the inflator. (The +absolute value of the velocity change is used.) +EQ.0: inactive. +DVMAG +Velocity change magnitude required to activate the inflator. +EQ.0: inactive. +UX +Displacement increment in local 𝑥-direction to activate the +inflator. (The absolute value of the 𝑥-displacement is used.) +EQ.0: inactive. +UY +UZ +*AIRBAG +DESCRIPTION +Displacement increment in local 𝑦-direction to activate the +inflator. (The absolute value of the 𝑦-displacement is used.) +EQ.0: inactive. +Displacement increment in local 𝑧-direction to activate the +inflator. (The absolute value of the 𝑧-displacement is used.) +EQ.0: inactive. +UMAG +Displacement magnitude required to activate the inflator. +EQ.0: inactive. +*AIRBAG_SIMPLE_PRESSURE_VOLUME_OPTION +Additional card for SIMPLE_PRESSURE_VOLUME option. (For card 1 see the “core +cards” section of *AIRBAG.) + Card 2 +Variable +1 +CN +2 +3 +4 +5 +6 +7 +8 +BETA +LCID +LCIDDR +Type +F +F +I +Default +none +none +none +I +0 + VARIABLE +DESCRIPTION +CN +Coefficient. Define if the load curve ID, LCID, is unspecified. +LT.0.0: |CN| is the load curve ID, which defines the coefficient +as a function of time. +Scale factor, 𝛽. Define if a load curve ID is not specified. +Optional load curve ID defining pressure versus relative volume. +Optional load curve ID defining the coefficient, CN, as a function +of time during the dynamic relaxation phase. +BETA +LCID +LCIDDR +Remarks: +The relationship is the following: +Pressure = +𝛽 × CN +Relative Volume +Relative Volume = +Current Volume +Initial Volume +The pressure is then a function of the ratio of current volume to the initial volume. The +constant, CN, is used to establish a relationship known from the literature. The scale +factor 𝛽 is simply used to scale the given values. This simple model can be used when +an initial pressure is given and no leakage, no temperature, and no input mass flow is +assumed. A typical application is the modeling of air in automobile tires. +The load curve, LCIDDR, can be used to ramp up the pressure during the dynamic +relaxation phase in order to avoid oscillations after the desired gas pressure is reached. +In the DEFINE_CURVE section this load curve must be flagged for dynamic relaxation. +After initialization either the constant or load curve ID, |CN| is used to determine the +pressure. +*AIRBAG_SIMPLE_AIRBAG_MODEL_OPTION +Additional cards for SIMPLE_AIRBAG_MODEL option. (For card 1 see the “core +cards” section of *AIRBAG.) + Card 2 +Variable +1 +CV +Type +F +2 +CP +F +3 +T +F +4 +5 +6 +LCID +MU +AREA +I +F +F +7 +PE +F +8 +RO +F +Default +none +none +none +none +none +none +none +none + Card 3 +1 +2 +Variable +LOU +T_EXT +Type +Default +Remarks +I +0 +0 +F +0. +3 +A +F +4 +B +F +0. +0. +5 +6 +7 +8 +MW +GASC +F +0. +F +0. +optional optional optional optional optional + VARIABLE +DESCRIPTION +CV +CP +T +LCID +Heat capacity at constant volume, e.g., Joules/kg/oK. +Heat capacity at constant pressure, e.g., Joules/kg/oK. +Temperature of input gas +Load curve ID specifying input mass flow rate. See *DEFINE_- +CURVE. +MU +Shape factor for exit hole, 𝜇: +LT.0.0: ∣𝜇∣ is the load curve number defining the shape factor as +a function of absolute pressure. +VARIABLE +DESCRIPTION +AREA +Exit area, A: +GE.0.0: A is the exit area and is constant in time, +LT.0.0: |A| is the load curve number defining the exit area as +a function of absolute pressure. +PE +RO +LOU +Ambient pressure, 𝑝𝑒 +Ambient density, 𝜌 +Optional load curve ID giving mass flow out versus gauge +pressure in bag. See *DEFINE_CURVE. +Leave the following 5 fields blank blank if CV ≠ 0 +T_EXT +Ambient temperature. +First heat +Joules/mole/oK). +capacity +Second heat +Joules/mole/oK2). +capacity +coefficient +of +inflator gas +(e.g., +coefficient of +inflator gas, +(e.g., +Molecular weight of inflator gas (e.g., Kg/mole). +Universal +Joules/mole/oK). +gas +constant +of +inflator +gas +(e.g., +8.314 +A +B +MW +GASC +Remarks: +The gamma law equation of state used to determine the pressure in the airbag: +𝑝 = (𝛾 − 1)𝜌𝑒 +where p is the pressure, 𝜌 is the density, 𝑒 is the specific internal energy of the gas, and 𝛾 +is the ratio of the specific heats: +𝛾 = +𝑐𝑝 +𝑐𝑣 +From conservation of mass, the time rate of change of mass flowing into the bag is given +as: +𝑑𝑀 +𝑑𝑡 += +𝑑𝑀in +𝑑𝑡 +− +𝑑𝑀out +𝑑𝑡 +The inflow mass flow rate is given by the load curve ID, LCID. Leakage, the mass flow +rate out of the bag, can be modeled in two alternative ways. One is to give an exit area +with the corresponding shape factor, then the load curve ID, LOU, must be set to zero. +The other is to define a mass flow out by a load curve, then 𝜇 and A have to both be set +to zero. +If CV = 0. then the constant-pressure specific heat is given by: +and the constant-volume specific heat is then found from: +𝑐𝑝 = +(𝑎 + 𝑏𝑇) +MW +𝑐𝑣 = 𝑐𝑝 − +MW +*AIRBAG_ADIABATIC_GAS_MODEL_OPTION +Additional card for ADIABATIC_GAS_MODEL option. (For card 1 see the “core +cards” section of *AIRBAG.) + Card 2 +1 +2 +3 +Variable +PSF +LCID +GAMMA +Type +F +I +F +4 +P0 +F +5 +PE +F +6 +RO +F +7 +8 +Default +1.0 +none +none +none +none +none + VARIABLE +DESCRIPTION +PSF +LCID +Pressure scale factor +Optional load curve for preload flag. See *DEFINE_CURVE. +GAMMA +Ratio of specific heats +P0 +PE +RO +Initial pressure (gauge) +Ambient pressure +Initial density of gas +Remarks: +The optional load curve ID, LCID, defines a preload flag. During the preload phase the +function value of the load curve versus time is zero, and the pressure in the control +volume is given as: +𝑝 = PSF × 𝑝0 +When the first nonzero function value is encountered, the preload phase stops and the +ideal gas law applies for the rest of the analysis. If LCID is zero, no preload is +performed. +The gamma law equation of state for the adiabatic expansion of an ideal gas is used to +determine the pressure after preload: +𝑝 = (𝛾 − 1)𝜌𝑒 +where p is the pressure, 𝜌 is the density, e is the specific internal energy of the gas, and +𝛾 is the ratio of the specific heats: +𝛾 = +𝑐𝑝 +𝑐𝑣 +The pressure above is the absolute pressure, the resultant pressure acting on the control +volume is: +𝑝𝑠 = PSF × (𝑝 − 𝑝𝑒) +where PSF is the pressure scale factor. Starting from the initial pressure 𝑝0 an initial +internal energy is calculated: +𝑒0 = +𝑝0 + 𝑝𝑒 +𝜌(𝛾 − 1) +*AIRBAG +The following sequence of cards is read in for the all variations of the WANG_NEFSKE +option to *AIRBAG. For card 1 see the “core cards” section of *AIRBAG. + Card 2 +Variable +1 +CV +Type +F +2 +CP +F +3 +T +F +Default +none +none +0. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +LCT +LCMT +TVOL +LCDT +IABT +I +0 +4 +I +F +I +F +none +0. +0. +not used +5 +6 +7 +8 +Variable +C23 +LCC23 +A23 +LCA23 +CP23 +LCCP23 +AP23 +LCAP23 +Type +F +Default +none + Card 4 +Variable +1 +PE +Type +F +I +0 +2 +RO +F +F +none +3 +GC +F +Default +none +none +none +I +0 +4 +F +none +5 +I +0 +6 +F +0.0 +7 +I +0 +8 +LCEFR +POVER +PPOP +OPT +KNKDN +I +0 +F +F +F +0.0 +0.0 +0.0 +I +Inflator Card. If the inflator is modeled, LCMT = 0 fill in the following card. If not, +include but leave blank. + Card 5 +1 +2 +3 +4 +Variable +IOC +IOA +IVOL +IRO +Type +F +F +F +F +5 +IT +F +6 +7 +8 +LCBF +I +Default +none +none +none +none +none +none +Temperature Dependent Heat Capacities Card. Include this card when CV = 0. + Card 6 +1 +Variable +TEXT +Type +F +2 +A +F +3 +B +F +4 +5 +6 +7 +8 +MW +GASC +HCONV +F +F +F +Default +none +none +none +none +none +none +Criteria for Initiating Exit Flow Card. Additional card for the POP option to the +*AIRBAG_WANG_NEFSKE card. + Card 7 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TDP +AXP +AYP +AZP +AMAGP +TDURP +TDA +RBIDP +Type +F +F +F +F +F +F +F +I +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +none + VARIABLE +DESCRIPTION +CV +CP +T +Specific heat at constant volume, e.g., Joules/kg/oK. +Specific heat at constant pressure, e.g., Joules/kg/oK. +Temperature of input gas. For temperature variations a load +curve, LCT, may be defined. +VARIABLE +DESCRIPTION +LCT +LCMT +TVOL +LCDT +IABT +C23 +LCC23 +A23 +LCA23 +Optional load curve number defining temperature of input gas +versus time. This overrides columns T. +Load curve specifying input mass flow rate or tank pressure +versus time. If the tank volume, TVOL, is nonzero the curve ID is +assumed to be tank pressure versus time. If LCMT = 0, then the +inflator has to be modeled, see Card 5. During the dynamic +relaxation phase the airbag is ignored unless the curve is flagged +to act during dynamic relaxation. +Tank volume which is required only for the tank pressure versus +time curve, LCMT. +Load curve for time rate of change of temperature (dT/dt) versus +time. +Initial airbag temperature. (Optional, generally not defined.) +Vent orifice coefficient which applies to exit hole. Set to zero if +LCC23 is defined below. +The absolute value, |LCC23|, is a load curve ID. If the ID is +positive, the load curve defines the vent orifice coefficient which +applies to exit hole as a function of time. If the ID is negative, the +vent orifice coefficient is defined as a function of relative +pressure, 𝑃air/𝑃bag, see [Anagonye and Wang 1999]. In addition, +LCC23 can be defined through *DEFINE_CURVE_FUNCTION. +A nonzero value for C23 overrides LCC23. +If defined as a positive number, A23 is the vent orifice area which +applies to exit hole. If defined as a negative number, the absolute +value |A23| is a part ID, see [Anagonye and Wang, 1999]. The +area of this part becomes the vent orifice area. Airbag pressure +will not be applied to part |A23| representing venting holes if +part |A23| is not included in SID, the part set representing the +airbag. Set A23 to zero if LCA23 is defined below. +Load curve number defining the vent orifice area which applies +to exit hole as a function of absolute pressure, or LCA23 can be +defined through *DEFINE_CURVE_FUNCTION. A nonzero +value for A23 overrides LCA23. +CP23 +Orifice coefficient for leakage (fabric porosity). Set to zero if +LCCP23 is defined below. +LCCP23 +*AIRBAG_WANG_NEFSKE +DESCRIPTION +Load curve number defining the orifice coefficient for leakage +(fabric porosity) as a function of time, or LCCP23 can be defined +through *DEFINE_CURVE_FUNCTION. A nonzero value for +CP23 overrides LCCP23. +AP23 +Area for leakage (fabric porosity) +LCAP23 +PE +RO +GC +Load curve number defining the area for leakage (fabric porosity) +as a function of (absolute) pressure, or LCAP23 can be defined +through *DEFINE_CURVE_FUNCTION. A nonzero value for +AP23 overrides LCAP23. +Ambient pressure +Ambient density +Gravitational conversion constant (mandatory - no default). If +consistent units are being used for all parameters in the airbag +definition then unity should be input. +LCEFR +Optional curve for exit flow rate (mass/time) versus (gauge) +pressure +POVER +Initial relative overpressure (gauge), Pover in control volume +PPOP +OPT +Pop Pressure: relative pressure (gauge) for initiating exit flow, +Ppop +Fabric venting option, if nonzero CP23, LCCP23, AP23, and +LCAP23 are set to zero. +EQ.1: Wang-Nefske formulas for venting through an orifice are +used. Blockage is not considered. +EQ.2: Wang-Nefske formulas for venting through an orifice are +used. Blockage of venting area due to contact is consid- +ered. +EQ.3: Leakage formulas of Graefe, Krummheuer, and Siejak +[1990] are used. Blockage is not considered. +EQ.4: Leakage formulas of Graefe, Krummheuer, and Siejak +[1990] are used. Blockage of venting area due to contact +is considered. +EQ.5: Leakage formulas based on flow through a porous media +are used. Blockage is not considered. +VARIABLE +DESCRIPTION +EQ.6: Leakage formulas based on flow through a porous media +are used. Blockage of venting area due to contact is con- +sidered. +EQ.7: Leakage is based on gas volume outflow versus pressure +load curve. Blockage of flow area due to contact is not +considered. Absolute pressure is used in the porous- +velocity-versus-pressure load curve, given as FAC(P) in +the *MAT_FABRIC card. +EQ.8: Leakage is based on gas volume outflow versus pressure +load curve. Blockage of flow area due to contact is con- +sidered. Absolute pressure is used in the porous- +velocity-versus-pressure load curve, given as FAC(P) in +the *MAT_FABRIC card. +Optional load curve ID defining the knock down pressure scale +factor versus time. This option only applies to jetting. The scale +factor defined by this load curve scales the pressure applied to +airbag segments which +do not have a clear line-of-sight to the jet. Typically, at very early +times this scale factor will be less than unity and equal to unity at +later times. The full pressure is always applied to segments +which can see the jets. +KNKDN +IOC +IOA +Inflator orifice coefficient +Inflator orifice area +IVOL +Inflator volume +IRO +IT +LCBF +TEXT +A +B +Inflator density +Inflator temperature +Load curve defining burn fraction versus time +Ambient temperature. +First molar heat capacity coefficient of +Joules/mole/oK) +inflator gas (e.g., +Second molar heat capacity coefficient of inflator gas, (e.g., +Joules/mole/oK2) +MW +GASC +HCONV +*AIRBAG_WANG_NEFSKE +DESCRIPTION +Molecular weight of inflator gas (e.g., Kg/mole). +Universal gas constant of inflator gas (e.g., 8.314 Joules/mole/oK) +Effective heat transfer coefficient between the gas in the air bag +and the environment at temperature TEXT. If HCONV < 0, then +HCONV defines a load curve of data pairs (time, hconv). +TDP +Time delay before initiating exit flow after pop pressure is +reached. +AXP +Pop acceleration magnitude in local x-direction. +EQ.0.0: Inactive. +AYP +Pop acceleration magnitude in local y-direction. +EQ.0.0: Inactive. +AZP +Pop acceleration magnitude in local z-direction. +EQ.0.0: Inactive. +AMAGP +Pop acceleration magnitude. +EQ.0.0: Inactive. +Time duration pop acceleration must be exceeded to initiate exit +flow. This is a cumulative time from the beginning of the +calculation, i.e., it is not continuous. +Time delay before initiating exit flow after pop acceleration is +exceeded for the prescribed time duration. +Part ID of the rigid body for checking accelerations against pop +accelerations. +TDURP +TDA +RBIDP +Remarks: +The gamma law equation of state for the adiabatic expansion of an ideal gas is used to +determine the pressure after preload: +𝑝 = (𝛾 − 1)𝜌𝑒 +where p is the pressure, 𝜌 is the density, e is the specific internal energy of the gas, and +𝛾 is the ratio of the specific heats: +𝛾 = +𝑐𝑝 +𝑐𝑣 +where cv is the specific heat at constant volume, and cp is the specific heat at constant +pressure. A pressure relation is defined: +𝑄 = +𝑝𝑒 +where pe is the external pressure and p is the internal pressure in the bag. A critical +pressure relationship is defined as: +𝑄crit = ( +𝛾 + 1 +𝛾−1 +) +where 𝛾 is the ratio of specific heats: +and +𝛾 = +𝑐𝑝 +𝑐𝑣 +𝑄 ≤ 𝑄crit⇒𝑄 = 𝑄crit. +Wang and Nefske define the mass flow through the vents and leakage by +and +𝑚̇ 23 = 𝐶23𝐴23 +𝑅√𝑇2 +𝛾√2𝑔𝑐 ( +𝛾𝑅 +𝛾 − 1 +) (1 − 𝑄 +𝛾−1 +𝛾 ) +𝑚′̇ +23 = 𝐶′23𝐴′23 +𝑅√𝑇2 +𝛾√2𝑔𝑐 ( +𝛾𝑅 +𝛾 − 1 +) (1 − 𝑄 +𝛾−1 +𝛾 ) +It must be noted that the gravitational conversion constant has to be given in consistent +units. As an alternative to computing the mass flow out of the bag by the Wang-Nefske +model, a curve for the exit flow rate depending on the internal pressure can be taken. +Then, no definitions for C23, LCC23, A23, LCA23, CP23, LCCP23, AP23, and LCAP23 +are necessary. +The airbag inflator assumes that the control volume of the inflator is constant and that +the amount of propellant reacted can be defined by the user as a tabulated curve of +fraction reacted versus time. A pressure relation is defined: +𝑄crit = +𝑝𝑐 +𝑝𝑖 += ( +𝛾 + 1 +𝛾−1 +) +where 𝑝𝑐 is a critical pressure at which sonic flow occurs, 𝑝𝐼, is the inflator pressure. +The exhaust pressure is given by +𝑝𝑒 = { +𝑝𝑎 +𝑝𝑐 +if 𝑝𝑎 ≥ 𝑝𝑐 +if 𝑝𝑎 < 𝑝𝑐 +where 𝑝𝑎 is the pressure in the control volume. The mass flow into the control volume +is governed by the equation: +√ +√ +√ +√ +𝑔𝑐𝛾 (𝑄 +𝛾 − 𝑄 +𝛾+1 +𝛾 ) +𝑚̇ in = 𝐶0𝐴0√2𝑝𝐼𝜌𝐼 +⎷ +where 𝐶0, 𝐴0, and 𝜌𝐼 are the inflator orifice coefficient, area, and gas density, +respectively. +𝛾 − 1 +If OPT is defined, then for OPT set to 1 or 2 the mass flow rate out of the bag, 𝑚̇ 𝑜𝑢𝑡 is +given by: +nairmats +𝑚̇ 𝑜𝑢𝑡 = √𝑔𝑐 { ∑ [FLC(𝑡)𝑛 × FAC(𝑝)𝑛 × Area𝑛] +} √2𝑝𝜌 +𝑛=1 +√ +√ +√ +√ +⎷ +𝑘 − 𝑄 +𝛾+1 +𝛾 ) +𝛾 (𝑄 +𝛾 − 1 +where, 𝜌 is the density of airbag gas, “nairmats” is the number of fabrics used in the +airbag, and “Arean” is the current unblocked area of fabric number n. +If OPT set to 3 or 4 then: +nairmats +𝑚̇ out = { ∑ [FLC(𝑡)𝑛 × FAC(𝑝)𝑛 × Area𝑛] +} √2(𝑝 − 𝑝ext)𝜌 +and for OPT set to 5 or 6: +𝑛=1 +nairmats +𝑚̇ out = { ∑ [FLC(𝑡)𝑛 × FAC(𝑝)𝑛 × Area𝑛] +} (𝑝 − 𝑝ext) +𝑛=1 +and for OPT set to 7 or 8 (may be comparable to an equivalent model ALE model): +nairmats +𝑚̇ out = ∑ FLC(𝑡)𝑛×FAC(𝑝)𝑛 × Area𝑛 × 𝜌𝑛 +𝑛=1 +Note that for different OPT settings, FAC(𝑝)𝑛 has different meanings (all units shown +just as demonstrations): +1. For OPT of 1, 2, 3 and 4, FAC(P) is unit-less. +2. For OPT of 5 and 6, FAC(P) has a unit of (s/m). +3. For OPT of 7 or 8, FAC(P) is the gas volume outflow through a unit area per +unit time thus has the unit of speed, +4. +[FAC(𝑃)] = [volume] +[area][𝑡] = [L]3 +[L]2[𝑡] += [𝐿] +[𝑡] = [velocity]. +Multiple airbags may share the same part ID since the area summation is over the +airbag segments whose corresponding part ID’s are known. Currently, we assume that +no more than ten materials are used per bag for purposes of the output. This constraint +can be eliminated if necessary. +The total mass flow out will include the portion due to venting, i.e., constants C23 and +A23 or their load curves above. +If CV = 0. then the constant-pressure specific heat is given by: +and the constant-volume specific heat is then found from: +𝑐𝑝 = +(𝑎 + 𝑏𝑇) +𝑀𝑊 +𝑐𝑣 = 𝑐𝑝 − +𝑀𝑊 +Two additional cards are required for JETTING models: +The following additional cards are defined for the WANG_NEFSKE_JETTING and +WANG_NEFSKE_MULTIPLE_JETTING options, two further cards are defined for each +option. The jet may be defined by specifying either the coordinates of the jet focal point, +jet vector head and secondary jet focal point, or by specifying three nodes located at +these positions. The nodal point option is recommended when the location of the +airbag changes as a function of time. +NOTE: For Jetting models define either of the two cards be- +low but not both. +Card format 8 for WANG_NEFSKE keyword option. + Card 8 +1 +2 +3 +4 +5 +6 +Variable +XJFP +YJFP +ZJFP +XJVH +YJVH +ZJVH +Type +F +F +F +F +F +F +7 +CA +F +8 +BETA +F +Default +none +none +none +none +none +none +none +1.0 +Remark +1 +1 +1 +1 +1 +Card format 8 for WANG_NEFSKE_MUTTIPLE_JETTING keyword options. + Card 8 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +XJFP +YJFP +ZJFP +XJVH +YJVH +ZJVH +LCJRV +BETA +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +1.0 +Remark +1 +1 +1 +1 +1 +1 +Card 9 for both WANG_NEFSKE_JETTING and WANG_NEFSKE_MULTIPLE_JET- +TING. + Card 9 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +XSJFP +YSJFP +ZSJFP +PSID +ANGLE +NODE1 +NODE2 +NODE3 +Type +F +F +F +I +F +Default +none +none +none +none +none +Remark +I +0 +1 +I +0 +1 +I +0 +Airbag +Gaussian velocity profile +Virtual origin +Node 1 +Node 2 +Hole diameter +Pressure is applied to surfaces +that are in the line of sight of +the virtual origin. +α: smaller +α: larger +Figure 3-1. Jetting configuration for driver's side airbag (pressure applied +only if centroid of surface is in line-of-sight) +Secondary focal jet point +Virtual origin +Node 1 +Node 3 +Gaussian profile +Node 2 +Figure 3-2. Jetting configuration for the passenger’s side bag. + VARIABLE +DESCRIPTION +XJFP +YJFP +x-coordinate of jet focal point, i.e., the virtual origin in Figures 3-1 +and 3-2. See Remark 1 below. +y-coordinate of jet focal point, i.e., the virtual origin in Figures 3-1 +and 3-2. +Relative jet +velocity +(degrees) +cut off angle, ψ +for ψ > ψ +cut v=0 +cut +Figure 3-3. Normalized jet velocity versus angle for multiple jet driver's side +airbag + VARIABLE +DESCRIPTION +ZJFP +XJVH +YJVH +ZJVH +CA +LCJRV +z-coordinate of jet focal point, i.e., the virtual origin in Figures 3-1 +and 3-2. +x-coordinate of jet vector head to defined code centerline +y-coordinate of jet vector head to defined code centerline +z-coordinate of jet vector head to defined code centerline +Cone angle, 𝛼, defined in radians. +LT.0.0: |𝛼| is the load curve ID defining cone angle as a function +of time +Load curve ID giving the spatial jet relative velocity distribution, +see Figures 3-1, 3-2, and 3-3. The jet velocity is determined from +the inflow mass rate and scaled by the load curve function value +corresponding to the value of the angle 𝜓. Typically, the values +on the load curve vary between 0 and unity. See *DEFINE_- +CURVE. +BETA +Efficiency factor, 𝛽, which scales the final value of pressure +obtained from Bernoulli’s equation. +LT.0.0: ∣𝛽∣ is the load curve ID defining the efficiency factor as a +function of time +cut +Figure 3-4. Multiple jet model for driver's side airbag. Typically, 𝜓cut is close to 90°. The angle 𝜓0 is included to indicate that there is +some angle below which the jet is negligible; see Figure 3-3. + VARIABLE +XSJFP +YSJFP +ZSJFP +PSID +ANGLE +DESCRIPTION +x-coordinate of secondary jet focal point, passenger side bag. If +the coordinates of the secondary point are (0,0,0) then a conical +jet (driver’s side airbag) is assumed. +y-coordinate of secondary jet focal point +z-coordinate of secondary jet focal point +Optional part set ID, see *SET_PART. If zero all elements are +included in the airbag. +Cutoff angle in degrees. The relative jet velocity is set to zero +for angles greater than the cutoff. See Figure 3-3. This option +applies to the MULTIPLE jet only. +NODE1 +Node ID located at the jet focal point, i.e., the virtual origin in +Figures 3-1 and 3-2. See Remark 1 below. +NODE2 +Node ID for node along the axis of the jet. +NODE3 +Optional node ID located at secondary jet focal point. +*AIRBAG_WANG_NEFSKE +1. +It is assumed that the jet direction is defined by the coordinate method (XJFP, +YJFP, ZJFP) and (XJVH, YJVH, ZJVH) unless both NODE1 and NODE2 are +defined. In which case the coordinates of the nodes give by NODE1, NODE2 +and NODE3 will override (XJFP, YJFP, ZJFP) and (XJVH, YJVH, ZJVH). The +use of nodes is recommended if the airbag system is undergoing rigid body +motion. The nodes should be attached to the vehicle to allow for the coordi- +nates of the jet to be continuously updated with the motion of the vehicle. +2. The jetting option provides a simple model to simulate the real pressure +distribution in the airbag during the breakout and early unfolding phase. Only +the surfaces that are in the line of sight to the virtual origin have an increased +pressure applied. With the optional load curve LCRJV, the pressure distribu- +tion with the code can be scaled according to the so-called relative jet velocity +distribution. +3. For passenger side airbags the cone is replaced by a wedge type shape. The +first and secondary jet focal points define the corners of the wedge and the +angle 𝛼 then defines the wedge angle. +4. +Instead of applying pressure to all surfaces in the line of sight of the virtual +origin(s), a part set can be defined to which the pressure is applied. +5. Care must be used to place the jet focal point within the bag. If the focal point +is outside the bag, inside surfaces will not be visible so jetting pressure will not +be applied correctly. +Additional card required for CM option: +The following additional card is defined for the WANG_NEFSKE_JETTING_CM and +WANG_NEFSKE_MULTIPLE_JETTING_CM options. +Additional card required for CM keyword option. + Card 10 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NREACT +Type +I +Default +none +Remark + VARIABLE +NREACT +Remarks: +DESCRIPTION +Node for reacting jet force. If zero the jet force will not be +applied. +Compared with the standard LS-DYNA jetting formulation, the Constant Momentum +option has several differences. Overall, the jetting usually has a more significant effect +on airbag deployment than the standard LS-DYNA jetting: the total force is often +greater, and does not reduce with distance from the jet. +The velocity at the jet outlet is assumed to be a choked (sonic) adiabatic flow of a perfect +gas. Therefore the velocity at the outlet is given by: +𝑣outlet = √𝛾𝑅𝑇 = √ +(𝑐𝑝 − 𝑐𝑣)𝑇𝑐𝑝 +𝑐𝑣 +The density in the nozzle is then calculated from conservation of mass flow. +𝜌0𝜈outlet𝐴outlet = 𝑚̇ +This is different from the standard LS-DYNA jetting formulation, which assumes that +the density of the gas in the jet is the same as atmospheric air, and then calculates the jet +velocity from conservation of mass flow. +The velocity distribution at any radius, 𝑟, from the jet centerline and distance, 𝑧, from +the focus, 𝑣𝑟,𝑧relates to the velocity of the jet centerline, 𝑣𝑟 = 0, 𝑧, in the same way as the +standard LS-DYNA jetting options: +𝑣𝑟,𝑧 = 𝑣𝑟=0,𝑧𝑒−( 𝑟 +𝛼𝑧) +The velocity at the jet centerline, 𝑣𝑟 = 0, at the distance, 𝑧, from the focus of the jet is +calculated such that the momentum in the jet is conserved. +momentum at nozzle = momentum at z +𝜌0𝑣outlet +𝐴outlet = 𝜌0 ∫ 𝑣jet +2 𝑑𝐴jet += 𝜌0𝑣𝑟=0,𝑍 +{𝑏 + 𝐹√𝑏} +where, 𝑏 = 𝜋(𝛼𝑧)2 +, and 𝐹 is the distance between the jet foci (for a passenger jet). +Finally, the pressure exerted on an airbag element in view of the jet is given as: +By combining the equations above +2 +𝑝𝑟,𝑧 = 𝛽𝜌0𝑣𝑟,𝑧 +𝑝𝑟,𝑧 = +] +𝛽𝑚̇ 𝑣outlet[𝑒−(𝑟/𝛼𝑧)2 +{⎧𝜋(𝛼𝑧)2 +⎩{⎨ ++ 𝐹√𝜋(𝛼𝑧)2 +}⎫ +⎭}⎬ +The total force exerted by the jet is given by +𝐹jet = 𝑚̇ 𝑣outlet, +which is independent of the distance from the nozzle. Mass flow in the jet is not +necessarily conserved, because gas is entrained into the jet from the surrounding +volume. By contrast, the standard LS-DYNA jetting formulation conserves mass flow +but not momentum. This has the effect of making the jet force reduce with distance +from the nozzle. +The jetting forces can be reacted onto a node (NREACT), to allow the reaction force +through the steering column or the support brackets to be modeled. The jetting force is +written to the ASCII abstat file and the binary xtf file. +*AIRBAG +Additional card required for LOAD_CURVE option. (For card 1 see the “core cards” +section of *AIRBAG.) + Card 2 +1 +2 +Variable +STIME +LCID +Type +F +I +3 +RO +F +4 +PE +F +5 +P0 +F +6 +T +F +7 +T0 +F +8 +Default +0.0 +none +none +none +none +none +none + VARIABLE +DESCRIPTION +Time at which pressure is applied. The load curve is offset by this +amount. +Load curve ID defining pressure versus time, see *DEFINE_- +CURVE. +Initial density of gas (ignored if LCID > 0) +Ambient pressure (ignored if LCID > 0) +Initial gauge pressure (ignored if LCID > 0) +Gas Temperature (ignored if LCID > 0) +Absolute zero on temperature scale (ignored if LCID > 0) +STIME +LCID +RO +PE +P0 +T +T0 +Remarks: +Within this simple model the control volume is inflated with a pressure defined as a +function of time or calculated using the following equation if LCID = 0. +𝑃total = 𝐶𝜌(𝑇 − 𝑇0) +𝑃gauge = 𝑃total − 𝑃ambient +The pressure is uniform throughout the control volume. +*AIRBAG_LINEAR_FLUID +Additional card required for LINEAR_FLUID option. (For card 1 see the “core cards” +section of *AIRBAG.) + Card 2 +1 +Variable +BULK +Type +F +2 +RO +F +3 +4 +5 +6 +7 +8 +LCINT +LCOUTT +LCOUTP +LCFIT +LCBULK +LCID +I +I +I +I +I +I +Default +none +none +none optional optional optional optional +none +Card 3 is optional. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +P_LIMIT P_LIMLC +Type +F +I +Default optional optional + VARIABLE +BULK +DESCRIPTION +K, bulk modulus of the fluid in the control volume. Constant as a +function of time. Define if LCBULK = 0. +RO +𝜌, density of the fluid +LCINT +LCOUTT +LCOUTP +LFIT +𝐹(𝑡) input flow curve defining mass per unit time as a function of +time, see *DEFINE_CURVE. +𝐺(𝑡), output flow curve defining mass per unit time as a function +of time. This load curve is optional. +𝐻(𝑝), output flow curve defining mass per unit time as a function +of pressure. This load curve is optional. +𝐿(𝑡), added pressure as a function of time. This load curve is +optional. +VARIABLE +LCBULK +DESCRIPTION +Curve defining the bulk modulus as a function of time. This load +curve is optional, but if defined, the constant, BULK, is not used. +LCID +Load curve ID defining pressure versus time, see *DEFINE_- +CURVE. +P_LIMIT +Limiting value on total pressure (optional). +P_LIMLC +Curve defining the limiting pressure value as a function of time. +If nonzero, P_LIMIT is ignored. +Remarks: +If LCID = 0 then the pressure is determined from: +𝑃(𝑡) = 𝐾(𝑡)ln [ +𝑉0(𝑡) +𝑉(𝑡) +] + 𝐿(𝑡). +where, +𝑃(𝑡) = Pressure, +𝑉(𝑡) = Volume of fluid in compressed state, +𝑉0(𝑡) = 𝑉0(𝑡) += +𝑀(𝑡) += Volume of fluid in uncompressed state, +𝑀(𝑡) = 𝑀(0) + ∫ 𝐹(𝑡)𝑑𝑡 − ∫ 𝐺(𝑡)𝑑𝑡 − ∫ 𝐻(𝑝)𝑑𝑡 += Current fluid mass, +𝑀(0) = 𝑉(0)𝜌 += Mass of fluid at time zero 𝑃(0) = 0. +By setting LCID ≠ 0 a pressure time history may be specified for the control volume and +the mass of fluid within the volume is then calculated from the volume and density. +This model is for the simulation of hydroforming processes or similar problems. The +pressure is controlled by the mass flowing into the volume and by the current volume. +The pressure is uniformly applied to the control volume. +Note the signs used in the equation for 𝑀(𝑡). The mass flow should always be defined +as positive since the output flow is subtracted. +*AIRBAG_HYBRID_OPTIONS +*AIRBAG_HYBRID_JETTING_OPTIONS +Additional cards required for HYBRID and HYBRID_JETTING options. (For card 1 see +the “core cards” section of *AIRBAG.) + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ATMOST ATMOSP ATMOSD +GC +CC +HCONV +Type +F +F +F +F +F +F +Default +none +none +none +none +1.0 +none + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +C23 +LCC23 +A23 +LCA23 +CP23 +LCP23 +AP23 +LCAP23 +Type +F +Default +none + Card 4 +1 +I +0 +2 +F +none +3 +I +0 +4 +F +none +5 +I +0 +6 +F +none +7 +I +0 +8 +Variable +OPT +PVENT +NGAS +LCEFR +LCIDM0 +VNTOPT +Type +I +F +I +Default +none +none +none +I +0 +I +0 +I +Include NGAS pairs of cards 5 and 6: + Card 5 +1 +2 +3 +4 +5 +Variable +LCIDM +LCIDT +MW +INITM +Type +I +I +F +F +6 +A +F +7 +B +F +8 +C +F +Default +none +none +none +none +none +none +none + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FMASS +Type +F +Default +none + VARIABLE +DESCRIPTION +ATMOST +Atmospheric temperature +ATMOSP +Atmospheric pressure +ATMOSD +Atmospheric density +GC +CC +HCONV +Universal molar gas constant +Conversion constant +EQ.0: Set to 1.0. +Effective heat transfer coefficient between the gas in the air bag +and the environment at temperature at ATMOST. If HCONV < 0, +then HCONV defines a load curve of data pairs (time, hconv). +C23 +Vent orifice coefficient which applies to exit hole. Set to zero if +LCC23 is defined below. +LCC23 +A23 +LCA23 +CP23 +LCCP23 +*AIRBAG_HYBRID +DESCRIPTION +The absolute value, |LCC23|, is a load curve ID. If the ID is +positive, the load curve defines the vent orifice coefficient which +applies to exit hole as a function of time. If the ID is negative, the +vent orifice coefficient is defined as a function of relative +pressure, 𝑃air/𝑃bag, see [Anagonye and Wang 1999]. In addition, +LCC23 can be defined through *DEFINE_CURVE_FUNCTION. +A nonzero value for C23 overrides LCC23 +If defined as a positive number, A23 is the vent orifice area which +applies to exit hole. If defined as a negative number, the absolute +value |A23| is a part ID, see [Anagonye and Wang 1999]. The area +of this part becomes the vent orifice area. Airbag pressure will +not be applied to part |A23| representing venting holes if part +|A23| is not included in SID, the part set representing the airbag. +Set A23 to zero if LCA23 is defined below. +Load curve number defining the vent orifice area which applies +to exit hole as a function of absolute pressure, or LCA23 can be +defined through *DEFINE_CURVE_FUNCTION. A nonzero +value for A23 overrides LCA23. +Orifice coefficient for leakage (fabric porosity). Set to zero if +LCCP23 is defined below. +Load curve number defining the orifice coefficient for leakage +(fabric porosity) as a function of time, or LCCP23 can be defined +through *DEFINE_CURVE_FUNCTION. A nonzero value for +CP23 overrides LCCP23. +AP23 +Area for leakage (fabric porosity) +LCAP23 +Load curve number defining the area for leakage (fabric porosity) +as a function of (absolute) pressure, or LCAP23 can be defined +through *DEFINE_CURVE_FUNCTION. A nonzero value for +AP23 overrides LCAP23. +VARIABLE +OPT +DESCRIPTION +Fabric venting option, if nonzero CP23, LCCP23, AP23, and +LCAP23 are set to zero. +EQ.1: Wang-Nefske formulas for venting through an orifice are +used. Blockage is not considered. +EQ.2: Wang-Nefske formulas for venting through an orifice are +used. Blockage of venting area due to contact is consid- +ered. +EQ.3: Leakage formulas of Graefe, Krummheuer, and Siejak +[1990] are used. Blockage is not considered. +EQ.4: Leakage formulas of Graefe, Krummheuer, and Siejak +[1990] are used. Blockage of venting area due to contact +is considered. +EQ.5: Leakage formulas based on flow through a porous media +are used. Blockage due to contact is not considered. +EQ.6: Leakage formulas based on flow through a porous media +are used. Blockage due to contact is considered. +EQ.7: Leakage is based on gas volume outflow versus pressure +load curve. Blockage of flow area due to contact is not +considered. Absolute pressure is used in the porous- +velocity-versus-pressure load curve, given as FAC(𝑃) in +the *MAT_FABRIC card. +EQ.8: Leakage is based on gas volume outflow versus pressure +load curve. Blockage of flow area due to contact is con- +sidered. +PVENT +Gauge pressure when venting begins +NGAS +LCEFR +LCIDM0 +Number of gas inputs to be defined below (Including initial air). +The maximum number of gases is 17. +Optional curve for exit flow rate (mass/time) versus (gauge) +pressure +Optional curve representing inflator’s total mass inflow rate. +When defined, LCIDM in the following 2 × NGAS cards defines +the molar fraction of each gas component as a function of time +and INITM defines the initial molar ratio of each gas component. +*AIRBAG_HYBRID +DESCRIPTION +VNTOPT +Additional options for venting area definition. +For A23 ≥ 0 +EQ.1: Vent area is equal to A23. +EQ.2: Vent area is A23 plus the eroded surface area of the +airbag parts. +EQ.10: Same as VNTOPT = 2 +For A23 < 0 +EQ.1: Vent area is the increase in surface area of part |A23|. If +there is no change in surface area of part |A23| over the +initial surface area or if the surface area reduces from +the initial area, there is no venting. +EQ.2: Vent area is the total (not change in) surface area of part +|A23| plus the eroded surface area of all other parts +comprising the airbag. +EQ.10: Vent area is the increase in surface area of part |A23| +plus the eroded surface area of all other parts compris- +ing the airbag. +LCIDM +Load curve ID for inflator mass flow rate (eq. 0 for gas in the bag +at time = 0) +GT.0: piecewise linear interpolation +LT.0: cubic spline interpolation +LCIDT +Load curve ID for inflator gas temperature (eq.0 for gas in the bag +at time 0) +GT.0: piecewise linear interpolation +LT.0: cubic spline interpolation +MW +Molecular weight +INITM +Initial mass fraction of gas component present in the airbag, prior +to injection of gas by the inflator +A +B +Coefficient for molar heat capacity of inflator gas at constant +pressure, (e.g., Joules/mole/oK) +Coefficient for molar heat capacity of inflator gas at constant +pressure, (e.g., Joules/mole/oK2) +VARIABLE +DESCRIPTION +C +Coefficient for molar heat capacity of inflator gas at constant +pressure, (e.g., Joules/mole/oK3) +FMASS +Fraction of additional aspirated mass. +Aditional cards are required for HYBRID_JETTING and HYBRID_JETTING_CM +The following two additional cards are defined for the HYBRID_JETTING options. The +jet may be defined by specifying either the coordinates of the jet focal point, jet vector +head and secondary jet focal point, or by specifying three nodes located at these +positions. The nodal point option is recommended when the location of the airbag +changes as a function of time. + Card 7 +1 +2 +3 +4 +5 +6 +Variable +XJFP +YJFP +ZJFP +XJVH +YJVH +ZJVH +Type +F +F +F +F +F +F +7 +CA +F +8 +BETA +F +Default +none +none +none +none +none +none +none +none +Remark +1 + Card 8 +1 +1 +2 +1 +3 +1 +4 +1 +5 +1 +6 +7 +8 +Variable +XSJFP +YSJFP +ZSJFP +PSID +IDUM +NODE1 +NODE2 +NODE3 +Type +F +F +F +I +F +Default +none +none +none +none +none +Remark +2 +I +0 +1 +I +0 +1 +I +0 +Additional card required for HYBRID_JETTING_CM option. + Card 9 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NREACT +Type +I +Default +none +Remark +4 + VARIABLE +DESCRIPTION +XJFP +YJFP +ZJFP +XJVH +YJVH +ZJVH +CA +𝑥-coordinate of jet focal point, i.e., the virtual origin in Figures 3-1 +and 3-2. See Remark 1 below. +𝑦-coordinate of jet focal point, i.e., the virtual origin in Figures 3-1 +and 3-2. +𝑧-coordinate of jet focal point, i.e., the virtual origin in Figures 3-1 +and 3-2. +𝑥-coordinate of jet vector head to defined code centerline +𝑦-coordinate of jet vector head to defined code centerline +𝑧-coordinate of jet vector head to defined code centerline +Cone angle, 𝛼, defined in radians. +LT.0.0: |𝛼| is the load curve ID defining cone angle as a function +of time +BETA +Efficiency factor, 𝛽, which scales the final value of pressure +obtained from Bernoulli’s equation. +LT.0.0: ∣𝛽∣ is the load curve ID defining the efficiency factor as a +function of time +XSJFP +𝑥-coordinate of secondary jet focal point, passenger side bag. If +the coordinate of the secondary point is (0,0,0) then a conical jet +(driver’s side airbag) is assumed. +YSJFP +𝑦-coordinate of secondary jet focal point +VARIABLE +DESCRIPTION +ZSJFP +PSID +𝑧-coordinate of secondary jet focal point +Optional part set ID, see *SET_PART. If zero all elements are +included in the airbag. +IDUM +Dummy field (Variable not used) +NODE1 +Node ID located at the jet focal point, i.e., the virtual origin in +Figure 3-7. See Remark 1 below. +NODE2 +Node ID for node along the axis of the jet. +NODE3 +Optional node ID located at secondary jet focal point. +NREACT +Node for reacting jet force. If zero the jet force will not be +applied. +Remarks: +1. Jetting. It is assumed that the jet direction is defined by the coordinate method +(XJFP, YJFP, ZJFP) and (XJVH, YJVH, ZJVH) unless both NODE1 and NODE2 +are defined. In which case the coordinates of the nodes given by NODE1, +and +NODE2 +(XJVH, YJVH, ZJVH). The use of nodes is recommended if the airbag system is +undergoing rigid body motion. The nodes should be attached to the vehicle to +allow for the coordinates of the jet to be continuously updated with the motion +of the vehicle. +and NODE3 will +(XJFP, YJFP, ZJFP) +override +The jetting option provides a simple model to simulate the real pressure distri- +bution in the airbag during the breakout and early unfolding phase. Only the +surfaces that are in the line of sight to the virtual origin have an increased pres- +sure applied. With the optional load curve LCRJV, the pressure distribution +with the code can be scaled according to the so-called relative jet velocity distri- +bution. +For passenger side airbags the cone is replaced by a wedge type shape. The +first and secondary jet focal points define the corners of the wedge and the +angle 𝛼 then defines the wedge angle. +Instead of applying pressure to all surfaces in the line of sight of the virtual +origin(s), a part set can be defined to which the pressure is applied. +2. +IDUM. This variable is not used and has been included to maintain the same +format as the WANG_NEFSKE_JETTING options. +3. Focal Point Placement. Care must be used to place the jet focal point within +the bag. If the focal point is outside the bag, inside surfaces will not be visible +so jetting pressure will not be applied correctly. +4. NREACT. See the description related to the WANG_NEFSKE_JETTING_CM +option. For the hybrid inflator model the heat capacities are compute from the +combination of gases which inflate the bag. +*AIRBAG_HYBRID_CHEMKIN_OPTION +The HYBRID_CHEMKIN model includes 3 control cards. For each gas species an +additional set of cards must follow consisting of a control card and several +thermodynamic property data cards. (For card 1 see the “core cards” section of +*AIRBAG.) + Card 2 +1 +2 +3 +4 +5 +6 +Variable +LCIDM +LCIDT +NGAS +DATA +ATMT +ATMP +Type +I +I +I +I +F +F +8 +7 +RG +F +Default +none +none +none +none +none +none +none + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +HCONV +Type +F +Default +0. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +C23 +A23 +Type +F +Default +0. +F +0. + VARIABLE +DESCRIPTION +LCIDM +Load curve specifying input mass flow rate versus time. +GT.0: piece wise linear interpolation +LT.0: cubic spline interpolation +*AIRBAG_HYBRID_CHEMKIN +DESCRIPTION +LCIDT +Load curve specifying input gas temperature versus time. +GT.0: piece wise linear interpolation +LT.0: cubic spline interpolation +NGAS +DATA +Number of gas inputs to be defined below. (Including initial air) +Thermodynamic database +EQ.1: NIST database (3 additional property cards are required +below) +EQ.2: CHEMKIN database (no additional property cards are +required) +EQ.3: Polynomial data (1 additional property card is required +below) +ATMT +ATMP +Atmospheric temperature. +Atmospheric pressure +RG +Universal gas constant +HCONV +Effective heat transfer coefficient between the gas in the air bag +and the environment at temperature ATMT. If HCONV < 0, then +HCONV defines a load curve of data pairs (time, hconv). +C23 +A23 +Vent orifice coefficient +Vent orifice area +NGAS Sets of Gas Species Data Cards: +For each gas species include a set of cards consisting of a Gas Species Control Card +followed by several thermo-dynamic property data cards whose format depends on the +DATA parameter on card in format “card 5”. The next "*" card terminates the reading +of this data. +Gas Species Control Card. + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CHNAME +MW +LCIDN +FMOLE +FMOLET +Type +A +F +Default +none +none +I +0 +F +F +none +0. + VARIABLE +CHNAME +DESCRIPTION +Chemical symbol for this gas species (e.g., N2 for nitrogen, AR for +argon). +Required for DATA = 2 (CHEMKIN), optional for DATA = 1 or +DATA = 3. +MW +Molecular weight of this gas species. +LCIDN +Load curve specifying the input mole fraction versus time for this +gas species. If > 0, FMOLE is not used. +FMOLE +Mole fraction of this gas species in the inlet stream. +FMOLET +Initial mole fraction of this gas species in the tank. +Additional thermodynamic data cards for each gas species. +If DATA = 1, include the following 3 cards for the NIST database: +The required data can be found on the NIST web site at http://webbook.nist.gov/ +chemistry/. + Card 5a +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TLOW +TMID +THIGH +Type +F +F +F +Default +none +none +none + Card 5b +1 +2 +3 +4 +5 +6 +7 +8 +Variable +alow +blow +clow +dlow +elow +flow +hlow +Type +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none + Card 5c +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ahigh +bhigh +chigh +dhigh +ehigh +fhigh +hhigh +Type +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none + VARIABLE +DESCRIPTION +TLOW +TMID +Curve fit low temperature limit. +Curve fit low-to-high transition temperature. +THIGH +Curve fit high temperature limit. +VARIABLE +alow, …, hlow +DESCRIPTION +Low temperature range NIST polynomial curve fit coefficients +. +ahigh, …, hhigh +High temperature range NIST polynomial curve fit coefficients +. +No additional cards are needed if using the CHEMKIN database (DATA = 2): +6 +7 +8 +Polynomial Fit Card (DATA = 3). + Card 5d +Variable +Type +1 +a +F +2 +b +F +3 +c +F +4 +d +F +5 +e +F +Default +none +0. +0. +0. +0. + VARIABLE +DESCRIPTION +a +b +c +d +e +Coefficient, see below. +Coefficient, see below. +Coefficient, see below. +Coefficient, see below. +Coefficient, see below. +Specific heat curve fits: +NIST: +𝑐𝑝 = +CHEMKIN: +𝑐𝑝 = +POLYNOMIAL: +𝑐𝑝 = +(𝑎 + 𝑏𝑇 + 𝑐𝑇2 + 𝑑𝑇3 + +𝑇2) +(𝑎 + 𝑏𝑇 + 𝑐𝑇2 + 𝑑𝑇3 + 𝑒𝑇4) +(𝑎 + 𝑏𝑇 + 𝑐𝑇2 + 𝑑𝑇3 + 𝑒𝑇4) +𝑅̅̅̅̅̅ +𝑅̅̅̅̅̅ = universal gas constant 8.314 +Nm +mole × 𝐾 +where, +𝑀 = gas molecular weight +*AIRBAG_FLUID_AND_GAS_OPTIONS +Additional cards required for FLUID_AND_GAS option. (For card 1 see the “core +cards” section of *AIRBAG.) Currently this option only works in SMP and explicit +analysis. + Card 2 +1 +2 +3 +Variable +XWINI +XWADD +XW +Type +F +F +F +4 +P +F +5 +6 +7 +8 +TEND +RHO +LCXW +LCP +F +F +I +I +Default +none +none +none +none +none +none +none +none + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +GDIR +NPROJ +IDIR +IIDIR +KAPPA +KBM +Type +F +Default +none +I +3 +I +I +F +F +none +none +1.0 +none + VARIABLE +DESCRIPTION +XWINI +Fluid level at time 𝑡 = 0 in |GDIR| direction. +XWADD +Fluid level filling increment per time step. +XW +P +Final fluid level in filling process. +Gas pressure at time 𝑡 = TEND. +TEND +Time when gas pressure P is reached. +RHO +LCXW +LCP +Density of the fluid (e.g. for water, RHO ≈ 1.0 kg/m3) +Load curve ID for fluid level vs. time. XW, XWADD, and XWINI +are with this option. +Load curve ID for gas pressure vs. time. P and TEND are +ignored with this option. +GDIR +*AIRBAG_FLUID_AND_GAS +DESCRIPTION +Global direction of gravity (e.g. -3.0 for negative global z-axis). +EQ.1.0: global 𝑥-direction, +EQ.2.0: global 𝑦-direction, +EQ.3.0: global 𝑧-direction. +NPROJ +IDIR +IIDIR +Number of projection directions (only global axis) for volume +calculation. +First direction of projection (if ∣NPROJ∣ ≠ 3), only global axis. +Second direction of projection (if |NPROJ| = 2), only global axis. +KAPPA +Adiabatic exponent +KBM +Bulk modulus of the fluid (e.g. for water, BKM ≈ 2080 N/mm2) +Remarks: +The *AIRBAG_FLUID_AND_GAS option models a quasi-static multi chamber +fluid/gas structure interaction in a simplified way including three possible load cases: +(i) only gas, (ii) only incompressible fluid, or (iii) the combination of incompressible +fluid with additional gas “above”. see Figure 3-5. +Figure 3-5. Hydrostatic pressure distribution in a chamber filled with gas and +incompressible fluid +The theory is based on the description of gases and fluids as energetically equivalent +pressure loads. The calculation of the fluid volume is carried out using the directions of +projection and a non-normalized normal vector. This model, therefore, requires that the +normal of the shell elements belonging to a filled structure must point outwards. Holes +are not detected, but can be taken into account as described below. +In case of a pure gas (no fluid), the *AIRBAG_SIMPLE_PRESSURE_VOLUME and +*AIRBAG_FLUID_AND_GAS cards give identical results as they are based on the same +theory. The update of the gas pressure due to volume change is calculated with the +following simple gas law +𝑝𝑔 = +⎜⎛1 − KAPPA × +⎝ +𝑣𝑔 − 𝑣old +𝑣old +𝑔 +⎟⎞ 𝑝old +⎠ +with adiabatic exponent KAPPA and gas volume 𝑣𝑔. +The theory of incompressible fluids is based on the variation of the potential energy and +an update of the water level due to changes in the volume and the water surface, see +Haßler and Schweizerhof [2007], Haßler and Schweizerhof [2008], Rumpel and +Schweizerhof [2003], and Rumpel and Schweizerhof [2004]. +In case of multiple fluid/gas filled chambers each chamber requires an additional +*AIRBAG_FLUID_AND_GAS card. Some of the parameters which are called local +parameters only belong to a single chamber (e.g. gas pressure). In contrast global, +parameters belong to all chambers (e.g. direction of gravitation). +Because the theory only applies to quasi-static fluid-structure interaction the load has to +be applied slowly so that the kinetic energy is almost zero throughout the process. +All parameters of card 1 are local parameters describing the filling of the chamber. The +water level and the gas pressure can be defined by curves using LCXW and LCP. A +second possibility are the parameters XWINI, XW, XWADD, P and TEND. When +describing the fluid and gas filling using the parameters the gas pressure at time 𝑡 = 0 is +set to 0 and the initial water level is set to XWINI in |GDIR|-direction. At each +timestep, XWADD is added to the water level, until XW is reached. The gas pressure +will be raised until P is reached at time 𝑡 = TEND. +In general, global parameters belong to all chambers. To describe the global axis in +GDIR, NPROJ, IDIR and IIDIR the following relations apply: 𝑥-axis is axis “1”, the 𝑦- +axis is axis “2”, and the 𝑧-axis is axis 3. +The gas and fluid volume is calculated by contour integrals in the global 𝑥-, 𝑦- and 𝑧- +coordinates. If one of the boundaries is discontinuous in one or two global directions, +these directions have to be ignored in NPROJ, IDIR and IIDIR. At least one direction of +projection must be set (NPROJ = 1, IDIR = value), but it is recommended to use as many +directions of projection as possible. +In case of a structure filled exclusively with fluid, IDIR and IIDIR should not be set to +|GDIR|. In case of holes in a structure (e.g. to take advantage of symmetry planes), +IDIR and IIDIR should not be set to the normal direction of the plane describing the +hole or symmetry plane. +An example of a water filled tube structure illustrating how to use NPROJ, IDIR, IIDIR, +and GDIR is shown in Figure 3-6. In this example gravity is acting opposite to the +global 𝑧-axis. In this case, then, GDIR = -3. The structure is filled exclusively with +water, so the projection direction cannot be set to |GDIR| = 3. To use the symmetry of +the tube only half of the structure has been modeled. The normal of the symmetry +plane shows in 𝑦 direction, so the projection direction cannot be set to 2. Because the +symmetry axes (2 and 3) are not allowed, the only direction of projection is 1; therefore, +NPROJ = 1 and IDIR = 1. +Figure 3-6. Example for water filled tube structure +For further explanations and examples see Haßler and Schweizerhof [2007], Haßler and +Schweizerhof [2008], and Maurer, Gebhardt, and Schweizerhof [2010]. +The possible entries for NPROJ, IDIR and IIDIR are: +NPROJ +IDIR IIDIR +3 +2 +2 +2 +1 +1 +1 +2 +3 +3 +1 +1 +2 +1 +2 +*AIRBAG +Purpose: The input in this section provides a simplified approach to defining the +deployment of the airbag using the ALE capabilities with an option to switch from the +initial ALE method to control volume (CV) method (*AIRBAG_HYBRID) at a chosen +time. An enclosed airbag (and possibly the airbag canister/compartment and/or a +simple representation of the inflator) shell structure interacts with the inflator gas(es). +This definition provides a single fluid to structure coupling for the airbag-gas +interaction during deployment in which the CV input data may be used directly. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SID +SIDTYP +MWD +SPSF +Type +I +I +Default +none +none +F +0 +F +0 +Remark +1 + VARIABLE +SID +DESCRIPTION +Set ID as defined on *AIRBAG card. This set ID contains the +Lagrangian elements (segments) which make up the airbag and +possibly the airbag canister/compartment and/or a simple +representation of the inflator. See Remark 1. +SIDTYP +Set type: +EQ.0: Segment set. +EQ.1: Part set. +MWD +SPSF +Mass weighted damping factor, D. This is used during the CV +phase for *AIRBAG_HYBRID. +Stagnation pressure scale factor, 0 ≤ 𝛾 ≤ 1. This is used during +the CV phase for *AIRBAG_HYBRID. +Card 2 +1 +2 +3 +Variable +ATMOST ATMOSP +Type +F +Default +0. +Remark +2 +F +0. +2 +*AIRBAG_ALE +4 +GC +F +5 +6 +7 +8 +CC +TNKVOL +TNKFINP +F +F +F +none +1.0 +0.0 +0.0 +10 +10 + VARIABLE +DESCRIPTION +ATMOST +Atmospheric ambient temperature. See Remark 2. +ATMOSP +Atmospheric ambient pressure. See Remark 2. +GC +CC +TNKVOL +Universal molar gas constant. +Conversion constant. If EQ: .0 Set to 1.0. +Tank volume from the inflator tank test or Inflator canister +volume. See remark 10. +LCVEL = 0 and TNKFINP is defined: +TNKVOL is the defined Tank. Inlet gas velocity is estimat- +ed by LS-DYNA method (testing). +LCVEL = 0 and TNKFINP is not defined +TNKVOL is the estimated inflator canister volume Inlet +gas velocity is estimated automatically by the Lian- +Bhalsod-Olovsson method. +LCVEL ≠ 0 +This must be left blank. +TNKFINP +Tank final pressure from the inflator tank test data. Only define +this parameter for option 1 of TNKVOL definition above. See +Remark 10. +Coupling Card. See keyword *CONSTRAINED_LAGRANGE_IN_SOLID. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NQUAD +CTYPE +PFAC +FRIC +FRCMIN NORMTYP +ILEAK +PLEAK +Type +Default +I +4 +I +4 +F +F +F +0.1 +0.0 +0.3 +I +0 +I +2 +F +0.1 +Remark +13 +13 +14 + VARIABLE +NQUAD +DESCRIPTION +Number of (quadrature) coupling points for coupling Lagrangian +slave parts to ALE master solid parts. If NQUAD = n, then nXn +coupling points will be parametrically distributed over the +surface of each Lagrangian slave segment (default = 4). See +Remark 13. +CTYPE +Coupling type (default = 4, see Remark 13): +PFAC +EQ.4: (default) penalty coupling with DIREC = 2 implied. +EQ.6: penalty coupling in which DIREC is automatically set to +DIREC = 1 for the unfolded region and DIREC = 2 for +folded region. +Penalty factor. PFAC is a scale factor for scaling the estimated +stiffness of the interacting (coupling) system. It is used to +compute the coupling forces to be distributed on the slave and +master parts. +GT.0: Fraction of estimated critical stiffness (default = 0.1). +LT.0: -PFAC is a load curve ID. The curve defines the relative +coupling pressure (y-axis) as a function of the tolerable +fluid penetration distance (x-axis). +FRIC +Coupling coefficient of friction. +FRCMIN +Minimum fluid volume fraction in an ALE element to activate +coupling (default is 0.3). +*AIRBAG_ALE +DESCRIPTION +NORMTYP +Penalty coupling spring direction (DIREC 1 and 2): +EQ.0: normal vectors are interpolated from nodal normals +(default) +EQ.1: normal vectors are interpolated from segment normals. +ILEAK +Leakage control flag. Default = 2 (with energy compensation). +PLEAK +Leakage control penalty factor (default = 0.1) +Venting Hole Card. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IVSETID +IVTYPE +IBLOCK +VNTCOF +Type +Default +Remark +I +0 +4 +I +0 +I +0 +5 +F +0.0 +6 + VARIABLE +DESCRIPTION +IVSETID +Set ID defining the venting hole surface(s). See Remark 4. +IVTYPE +Set type of IVSETID: +EQ.0: Part Set (default). +EQ.1: Part ID. +EQ.2: Segment Set. +IBLOCK +Flag for considering blockage effects for porosity and vents : +EQ.0: no (blockage is NOT considered, default). +EQ.1: yes (blockage is considered). +VNTCOF +Vent Coefficient for scaling the flow. See Remark 6. +transformation. + Parameters for ALE mesh automatic definition and +its +*AIRBAG + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NX/IDA +NY/IDG +NZ +MOVERN +ZOOM +Type +I +I +I +Default +none +none +none +Remark +7 +7 +7 +I +0 +8 +I +0 +9 + VARIABLE +DESCRIPTION +Option 1: Automatic ALE mesh, activated by NZ.NE.0 (blank): +NX +NY +NZ +NX is the number of ALE elements to be generated in the x +direction. See remark 7. +NY is the number of ALE elements to be generated in the y +direction. See remark 7. +NZ is the number of ALE elements to be generated in the z +direction. See remark 7. +Option 2: ALE mesh from part ID: +IDAIR +IDAIR is the Part ID of the initial air mesh. See remark 7. +IDGAS +IDGAS is defined as Part ID of the initial gas mesh. See remark 7. +NZ +Leave blank to activate options 2. See remark 7. +Variables common to both options: +MOVERN +ALE mesh automatic motion option . +EQ.0: ALE mesh is fixed in space. +GT.0: Node group id. See *ALE_REFERENCE_SYSTEM_- +NODE ALE mesh can be moved with PRTYP = 5, mesh +motion follows a coordinate system defined by 3 refer- +ence nodes. +*AIRBAG_ALE +DESCRIPTION +ZOOM +ALE mesh automatic expansion option : +EQ.0: do not expand ALE mesh +EQ.1: Expand/contract ALE mesh by keeping all airbag parts +to +the ALE mesh +(equivalent +contained within +PRTYP = 9). +Origin for ALE Mesh Card. Include Cards 5a and 5b when NZ > 0. + Card 5a +Variable +1 +X0 +Type +F +2 +Y0 +F +3 +Z0 +F +4 +X1 +F +5 +Y1 +F +6 +Z1 +F +7 +8 +Default +none +none +none +none +none +none + Card 5b +Variable +1 +X2 +Type +F +2 +Y2 +F +3 +Z2 +F +4 +Z3 +F +5 +Y3 +F +6 +Z3 +F +7 +8 +Default +none +none +none +none +none +none + VARIABLE +DESCRIPTION +X0, Y0, Z0 +Coordinates of origin for ALE mesh generation (node0). +X1, Y1, Z1 +Coordinates of point 1 for ALE mesh generation (node1). +𝑥-extent = node1 − node0 +X2, Y2, Z2 +Coordinates of point 2 for ALE mesh generation (node2). +𝑦-extent = node2 − node0 +X3, Y3, Z3 +Coordinates of point 3 for ALE mesh generation(node3). +𝑧-extent = node3 − node0 +(x4, y4, z4) +(x1, y1, z1) +(x2, y2, z2) +( += +y(=3) +) +(x0, y0, z0) +8 ) +x( = +Figure 3-7. Illustration of automatic mesh generation for the ALE mesh in a +hexahederal region +Miscellaneous Parameters Card. +3 +HG +F +0. +4 +5 +6 +7 +8 +NAIR +NGAS +NORIF +LCVEL +LCT +I +0 +I +0 +I +0 +I +0 +I +0 +10 +11 + Card 6 +1 +2 +Variable +SWTIME +Type +F +Default +1e16 +Remarks +3 + VARIABLE +SWTIME +DESCRIPTION +Time to switch from ALE method to control volume (CV) +method. Once switched, a method similar to that used by the +*AIRBAG_HYBRID card is used. +HG +NAIR +Hourglass control for ALE fluid mesh(es). +Number of Air components. For example, this equals 2 in case air +contains 80% of N2 and 20% of O2. If air is defined as 1 single gas +then NAIR = 1. +NGAS +Number of inflator Gas components. +NORIF +LCVEL +*AIRBAG_ALE +DESCRIPTION +Number of point sources or orifices. This determines the number +of point source cards to be read. +Load curve ID for inlet velocity . This is the same estimated velocity curve used +in *SECTION_POINT_SOURCE_MIXTURE card. +LCT +Load curve ID for inlet gas temperature . +Air Component Card. Include NAIR cards, one for each air component. + Card 7 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +Default +Remarks +MWAIR +INITM +AIRA +AIRB +AIRC +F +0 +F +0 +F +0 +F +0. +F +0. +12 +12 +12 + VARIABLE +DESCRIPTION +MWAIR +Molecular weight of air component +INITA +AIRA +AIRB +AIRC +Initial Mass Fraction of Air component(s) +First Coefficient of molar heat capacity at constant pressure (e.g., +J/mole/K, remark 12). +Second Coefficient of molar heat capacity at constant pressure +(e.g., J/mole/K2, remark 12). +Third Coefficient of molar heat capacity at constant pressure (e.g., +J/mole/K3, remark 12). +Gas Component Card. Include NGAS cards, one for each gas component. + Card 8 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCMF +MWGAS +GASA +GASB +GASC +Type +I +Default +none +F +0 +F +0 +F +0. +F +0. +Remarks +11 +12 +12 +12 + VARIABLE +LCMF +DESCRIPTION +Load curve ID for mass flow rate . +MWGAS +Molecular weight of inflator gas components. +GASA +GASB +GASC +First Coefficient of molar heat capacity at constant pressure (e.g., +J/mole/K, remark 12). +Second Coefficient of molar heat capacity at constant pressure +(e.g., J/mole/K2, remark 12). +Third Coefficient of molar heat capacity at constant pressure (e.g., +J/mole/K3, remark 12). +Point Source Cards. Include NORIF cards, one for each point source. + Card 9 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NODEID +VECID +ORIFARE +Type +Default +I +0 +I +0 +I +0 + VARIABLE +DESCRIPTION +NODEID +The node ID defining the point source. +*AIRBAG_ALE +DESCRIPTION +VECID +The vector ID defining the direction of flow at the point source. +ORIFARE +The orifice area at the point source. +Remarks: +1. This set ID typically contains the Lagrangian segments of the 3 parts that are +coupled to the inflator gas: airbag, airbag canister (compartment), inflator. As +in all control-volume, orientation of elements representing bag and canister +should point outward. During the ALE phase the segment normal will be re- +versed automatically for fluid-structure coupling. However, the orientation of +inflator element normal vectors should point to its center. See Figure 3-8. +Bag fabric +Inflator +Canister +Figure 3-8. Arrows indicate “outward” normal +2. Atmospheric density for the ambient gas (air) can be computed from +𝜌amb = +𝑃amb +𝑅𝑇amb +3. Since ALL ALE related activities will be turned off after the switch from ALE +method to control-volume method, no other ALE coupling will exist beyond +t = SWTIME. +4. Vent definition will be used for ALE venting. Upon switching area of the +segments will be used for venting as a23 in *AIRBAG_HYBRID. +5. Fabric porosity for ALE and *AIRBAG_HYBRID can be defined on MAT_FAB- +RIC. Define FLC and FAC on *MAT_FABRIC. FVOPT 7 and 8 will be used for +both ALE and *AIRBAG_HYBRID. IBLOCK = 0 will use FVOPT = 7 and +IBLOCK = 1 will use FVOPT = 8. +6. VCOF will be used to scale the vent area for ALE venting and this coefficient +will be used as vent coefficient c23 for *AIRBAG_HYBRID upon switching. +7. +8. +If NX, NY and NZ are defined (option 1), card 5a and card 5b should be defined +to let LS-DYNA generate the mesh for ALE. Alternatively if NZ is 0 (option 2), +then NX = IDAIR and NY = IDGAS. In the latter case the user need to supply +the ALE mesh whose PID = IDAIR. +If the airbag moves with the vehicle, set MOVERN = GROUPID, this GROUPID +is defined using *ALE_REFERENCE_SYSTEM_NODE. The 3 nodes defined in +ALE_REFERENCE_SYSTEM_NODE will be used to transform the ALE mesh. +The point sources will also follow this motion. This simulates PRTYP = 5 in the +*ALE_REFERENCE_SYSTEM_GROUP card. +9. Automatic expansion/contraction of the ALE mesh to follow the airbag +expansion can be turned on by setting zoom = 1. This feature is particularly +useful for fully folded airbags requiring very fine ale mesh initially. As the +airbag inflates the ale mesh will be automatically scaled such that the airbag +will be contained within the ALE mesh. This simulates PRTYP = 9 in the +*ALE_REFERENCE_SYSTEM_GROUP card. +10. There are 3 methods for defining the inlet gas velocity: +a) Inlet gas velocity is estimated by LSDYNA method (testing), if +LCVEL = 0 ⇒ TNKVOL = Tank volume +and +TNKFINP = Tank final pressure from tank test data. +b) Inlet gas velocity is estimated automatically by Lian-Bhalsod-Olovsson +method if, +LCVEL = 0 ⇒ TNKVOL = Tank volume. +and +TNKFINP = blank. +c) Inlet gas velocity is defined by user via a load curve LCVEL if, +LCVEL = n, +TNKVOL = 0, +and +11. LCT and LCIDM should have the same number of sampling points. +TNKFINP = 0 +12. The per-mass-unit, temperature-dependent, constant-pressure heat capacity is +𝐶𝑝(𝑇) = +[𝐴 + 𝐵𝑇 + 𝐶𝑇2] +𝑀𝑊 +. +where, +these quantities often have units of, +𝐴 = 𝐶̃𝑝0 +𝐶𝑝(𝑇) +kg × K +𝐶 +mole × K +mole × K2 +mole × K3 +13. Sometimes CTYPE = 6 may be used for complex folded airbag. NQUAD = 2 +may be used as a starting value and increase as necessary depending on the +relative mesh resolutions of the Lagrangian and ALE meshes. +14. Use a load curve for PFAC whenever possible. It tends to be more robust. +Related Cards: +AIR ⟶ +GAS ⟶ +{⎧*PART (AMMG2) +*SECTION_SOLID +⎩{⎨ +*MAT_GAS_MIXTURE +{⎧*PART (AMMG1) +*SECTION_POINT_SOURCE_MIXTURE +⎩{⎨ +*MAT_GAS_MIXTURE +Couplings ⟶ *CONSTRAINED_LAGRANGE_IN_SOLID +ALE Mesh Motion ⟶ *ALE_REFERENCE_SYSTEM_GROUP +Control Volume ⟶ *AIRBAG_HYBRID +Vent ⟶ *AIRBAG_ALE/Card4 +Example 1: +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*AIRBAG_ALE +$#1 SID SIDTYPE NONE NONE NONE NONE MWD SPSF + 123 1 0 0 0 0 0.0 0.0 +$#2 ATMOST ATMOSP NONE GC CC TNKVOL TNKFP + 298.15 1.0132E-4 0 8.314 0.0 0.0 0.0 +$#3 NQUAD CTYPE PFAC FRIC FRCMIN NRMTYPE ILEAK PLEAK + 4 4 -1000 0.0 0.3 0 2 0.1 +$#4 VSETID IVSETTYP IBLOCK VENTCOEF + 1 2 0 1.00 +$#5NXIDAIR NYIDGAS NZ MOVERN ZOOM + 50000 50003 0 0 0 +$#6 SWTIME NONE HG NAIR NGAS NORIF LCVEL LCT + 1000.00 0.000 1.e-4 1 1 8 2002 2001 +$#7 AIR NONE NONE MWAIR INITM AIRA AIRB AIRC + 0 0 0 0.02897 1.00 29.100 0.00000 0.00000 +$#8 GASLCM NONE NONE MWGAS NONE GASA GASB GASC + 2003 0 0 0.0235 0 28.000 0.00000 0.00000 +$#9 NODEID VECTID ORIFAREA + 100019 1 13.500000 + 100020 2 13.500000 + 100021 3 13.500000 + 100022 4 13.500000 + 100023 5 13.500000 + 100024 6 13.500000 + 100017 7 13.500000 + 100018 8 13.500000 +$ PFAC CURVE = penalty factor curve. +*DEFINE_CURVE +$ lcid sidr sfa sfo offa offo dattyp + 1000 0 0.0 2.0 0.0 0.0 +$ a1 o1 + 0.0 0.00000000 + 1.0000000 4.013000e-04 +*SET_SEGMENT_TITLE +vent segments (defined in IVSETID) + 1 0.0 0.0 0.0 0.0 + 1735 1736 661 1697 0.0 0.0 0.0 0.0 + 1735 2337 1993 1736 0.0 0.0 0.0 0.0 + 1735 1969 1988 2337 0.0 0.0 0.0 0.0 + 1735 1697 656 1969 0.0 0.0 0.0 0.0 +*DEFINE_VECTOR +$# vid xt yt zt xh yh zh + 1 0.0 0.0-16.250000 21.213200 21.213200-16.250000 + 2 0.0 0.0-16.250000 30.000000-1.000e-06-16.250000 + 3 0.0 0.0-16.250000 21.213200-21.213200-16.250000 + 4 0.0 0.0-16.250000-1.000e-06-30.000000-16.250000 + 5 0.0 0.0-16.250000-21.213200-21.213200-16.250000 + 6 0.0 0.0-16.250000-30.0000001.0000e-06-16.250000 + 7 0.0 0.0-16.250000-21.213200 21.213200-16.250000 + 8 0.0 0.0-16.2500001.0000e-06 30.000000-16.250000 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +In this example, pre-existing background air mesh with part ID 50000 and gas mesh +with part ID 50003 are used. Thus NZ = 0. There is no mesh motion nor expansion +allowed. An inlet gas velocity curve is provided. +Example 2: +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +$ SIDTYP: 0=SGSID; 1=PSID +*AIRBAG_ALE +$#1 SID SIDTYPE NONE NONE NONE NONE MWD SPSF + 1 1 0 0. 0. 0. 0. 0. +$#2 ATMOST ATMOSP NONE GC CC TNKVOL TNKFP + 298. 101325. 0.0 8.314 1. 6.0E-5 0 +$#3 NQUAD CTYPE PFAC FRIC FRCMIN NRMTYPE ILEAK PLEAK + 2 6 -321 0.0 0.3 1 2 0.1 +$#4 VSETID IVSETTYP IBLOCK VENTCOEF + 0 0 0 0 +$#5NXIDAIR NYIDGAS NZ MOVERN ZOOM + 11 11 9 +$5b x0 y0 z0 x1 y1 z1 NOT-USED NOT-USED + -0.3 -0.3 -0.135 0.3 -0.3 -0.135 +$5c x2 y2 z2 x3 y3 z3 NOT-USED NOT-USED + -0.3 0.3 -0.135 -0.3 -0.3 0.39 +$#6 SWTIME NONE HG NAIR NGAS NORIF LCVEL LCT + 0.04000 0.005 1.e-4 2 1 1 0 2 +$#7 AIR NONE NONE MWAIR INITM AIRA AIRB AIRC + 0.028 0.80 27.296 0.00523 + 0.032 0.20 25.723 0.01298 +$#8 GASLCM NONE NONE MWGAS NONE GASA GASB GASC + 1 0.0249 29.680 0.00880 +$#9 NODEID VECTID ORIFAREA + 9272 1 1.00e-4 +$ Lagrangian shell structure to be coupled to the inflator gas +*SET_PART_LIST + 1 0.0 0.0 0.0 0.0 + 1 2 3 +*DEFINE_VECTOR +$0.100000E+01, 10.000000000 +$ vid xt yt zt xh yh zh + 1 0.0 0.0 0.0 0.0 0.0 0.100000 +$ bag penetration ~ 1 mm <====> P_coup ~ 500000 pascal ==> ~ 5 atm +*DEFINE_CURVE +$ lcid sidr sfa sfo offa offo dattyp + 321 0 0.0 0.0 0.0 0.0 +$ a1 o1 + 0.0 0.0 + 0.00100000 5.0000000e+05 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +In this example, LS-DYNA automatically creates the background ALE mesh with: +NX = 11 ⇒ 11 elements in the x direction +NY = 11 ⇒ 11 Elements in the y direction +NZ = 9 ⇒ 9 Elements in the z direction +*AIRBAG +Purpose: To define two connected airbags which vent into each other. + Card 1 +1 +2 +3 +Variable +AB1 +AB2 +AREA +Type +I +I +F +4 +SF +F +Default +none +none +none +none +5 +6 +7 +8 +PID +LCID +IFLOW +I +0 +I +0 +I +0 + VARIABLE +DESCRIPTION +AB1 +AB2 +First airbag ID, as defined on *AIRBAG card. +Second airbag ID, as defined on *AIRBAG card. +AREA +Orifice area between connected bags. +LT.0.0: |AREA| is the load curve ID defining the orifice area +as a function of absolute pressure. +EQ.0.0: AREA is taken as the surface area of the part ID +defined below. +SF +Shape factor. +LT.0.0: |SF| is the load curve ID defining vent orifice +coefficient as a function of relative time. +PID +LCID +Optional part ID of the partition between the interacting control +volumes. AREA is based on this part ID. If PID is negative, the +blockage of the orifice part due to contact is considered, +Load curve ID defining mass flow rate versus pressure difference, +see *DEFINE_CURVE. If LCID is defined AREA, SF and PID are +ignored. +IFLOW +Flow direction +LT.0: One way flow from AB1 to AB2 only. +EQ.0: Two way flow between AB1 and AB2. +GT.0: One way flow from AB2 to AB1 only. +*AIRBAG_INTERACTION +Mass flow rate and temperature load curves for the secondary chambers must be +defined as null curves, for example, in the DEFINE_CURVE definitions give two points +(0.0, 0.0) and (10000., 0.0). +All input options are valid for the following airbag types: +*AIRBAG_SIMPLE_AIRBAG_MODEL +*AIRBAG_WANG_NEFSKE +*AIRBAG_WANG_NEFSKE_JETTING +*AIRBAG_WANG_NEFSKE_MULTIPLE_JETTING +*AIRBAG_HYBRID +*AIRBAG_HYBRID_JETTING +The LCID defining mass flow rate vs. pressure difference may additionally be used +with: +*AIRBAG_LOAD_CURVE +*AIRBAG_LINEAR_FLUID +If the AREA, SF, and PID defined method is used to define the interaction then the +airbags must contain the same gas, i.e. Cp, Cv and g must be the same. The flow +between bags is governed by formulae which are similar to those of Wang-Nefske. +*AIRBAG_PARTICLE_{OPTION1}_{OPTION2}_{OPTION3}_{OPTION4} +Available options include: +OPTION1 applies to the MPP implementation only. +MPP +OPTION2 also applies to the MPP implementation only. When the DECOMPOSITON +option is present, LS-DYNA will automatically insert *CONTROL_MPP_DECOMPOSI- +TION_BAGREF +CONTROL_MPP_DECOMPOSITION_ARRANGE_PARTS +keywords if they are not already present in the input. +and +DECOMPOSITION +OPTION3 provides a means to specify an airbag ID number and a heading for the +airbag. +ID +TITLE +OPTION4: +MOLEFRACTION +Purpose: To define an airbag using the particle method. +NOTE: This model requires that surface normal vectors be oriented +inward, unlike that the traditional CV method for which they +must point outward. To check bag and chamber integrity in the +CPM model see the CPMERR option on the *CONTROL_CPM +card. +MPP Card. Additional card for MPP keyword option. +4 +5 +6 +7 +8 + MPP +Variable +1 +SX +Type +F +2 +SY +F +3 +SZ +F +Default +none +none +none +SX, SY, SZ +*AIRBAG_PARTICLE +DESCRIPTION +Scale factor for each direction used during the MPP decomposi- +tion. For instance, increasing SX from 1 to 10 will give increase +the probability that the model is divided along the 𝑥-direction. +Title Card. Additional card for ID or TITLE keyword options. +TITLE +1 +2 +3 +4 +5 +6 +7 +8 +Variable +BAGID +Type +I +HEADING +A60 +The BAGID is referenced in, e.g., *INITIAL_AIRBAG_PARTICLE_POSITION. + VARIABLE +DESCRIPTION +BAGID +Airbag ID. This must be a unique number. +HEADING +Airbag descriptor. It is suggested that unique descriptions be +used. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SID1 +STYPE1 +SID2 +STYPE2 +BLOCK +NPDATA +FRIC +IRPD +Type +I +Default +none + Card 2 +Variable +1 +NP +I +0 +2 +I +0 +3 +I +0 +4 +I +0 +5 +I +F +0.0 +0.0 +6 +7 +I +0 +8 +UNIT +VISFLG +TATM +PATM +NVENT +TEND +TSW +Type +I +I +Default 200,000 +0 +I +0 +F +F +293K +1 atm +I +0 +F +F +1010 +1010 +Optional control card. When the card after Card 2 begins with a “+” character the +input reader processes it as this card, otherwise this card is skipped. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TSTOP +TSMTH +OCCUP +REBL +SIDSV +PSID1 +Type +F +F +F +Default +1010 +1msec +0.1 +I +0 +I +I +none +none +Optional unit card. Additional Cards when Unit = 3. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +Mass +F +Time +F +Length +F +Default +none +none +none + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IAIR +NGAS +NORIF +NID1 +NID2 +NID3 +CHM +CD_EXT +Type +Default +I +0 +I +I +none +none +I +0 +I +0 +I +0 +I +F +none +0. +Internal Part Set Cards. Additional Cards for STYPE2 = 2. Define SID2 cards, one for +each internal part or part set. + Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SIDUP +STYUP +PFRAC +LINKING +Type +I +I +F +I +Default +none +none +0. +none +Heat Convection Part Set Cards. Additional Cards for NPDATA > 0. Define +NPDATA cards, one for each heat convection part or part set. + Card 7 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SIDH +STYPEH +HCONV +PFRIC +SDFBLK +KP +INIP +Type +I +I +F +F +F +Default +none +none +none +none +1.0 +F +0. +I +0 +Vent Hole Card. Additional Cards for NVENT > 0. Define NVENT cards, one for +vent hole. + Card 8 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SID3 +STYPE3 +C23 +LCTC23 +LCPC23 +ENH_V +PPOP +Type +Default +I +0 +I +F +none +1.0 +I +0 +I +0 +I +0 +F +0.0 +Air Card. Additional Card for IAIR > 0. + Card 9 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PAIR +TAIR +XMAIR +AAIR +BAIR +CAIR +NPAIR +NPRLX +Type +F +F +F +F +F +F +Default +PATM +TATM +none +none +0.0 +0.0 +I +0 +I/F +0 +MOLEFRACTION Card. Additional card for the MOLEFRACTION option. + Card 10 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCMASS +Type +I +Default +none +Gas Cards. NGAS additional Cards, one for each gas (card format for ith gas). + Card 11 +1 +2 +3 +Variable +LCMi +LCTi +XMi +Type +I +I +F +4 +Ai +F +5 +Bi +F +6 +Ci +F +Default +none +none +none +None +0.0 +0.0 +7 +8 +INFGi +I +Orifice Cards. NORIF additional Cards, one for each orifice (card format for ith orifice). + Card 12 +1 +Variable +NIDi +2 +ANi +3 +VDi +4 +5 +6 +7 +8 +CAi +INFOi +IMOM +IANG +CHM_ID +Type +I +F +I +F +Default +none +none +none +30 Deg +I +1 +I +0 +I +0 +I +0 + VARIABLE +DESCRIPTION +SID1 +Part or part set ID defining the complete airbag. +STYPE1 +Set type: +EQ.0: Part +EQ.1: Part set +SID2 +Part or part set ID defining the internal parts of the airbag. +STYPE2 +Set type: +EQ.0: Part +EQ.1: Part set +EQ.2: Number of parts to read (Not recommended for general +use) +VARIABLE +DESCRIPTION +BLOCK +Blocking. Block must be set to a two-digit number +BLOCK = M × 10 + N, +The 10’s digit controls the treatment of particles that escape due +to deleted elements (particles are always tracked and marked). +M.EQ.0: Active particle method for which causes particles to be +put back into the bag. +M.EQ.1: Particles are leaked through vents. See Remark 3. +The 1’s digit controls the treatment of leakage. +N.EQ.0: Always consider porosity leakage without considering +blockage due to contact. +N.EQ.1: Check if airbag node is in contact or not. If yes, 1/4 +(quad) or 1/3 (tri) of the segment surface will not have +porosity leakage due to contact. +N.EQ.2: Same as 1 but no blockage for external vents +N.EQ.3: Same as 1 but no blockage for internal vents +N.EQ.4: Same as 1 but no blockage for all vents. +NPDATA +Number of parts or part sets data. +FRIC +IRPD +Friction factor. See Remark 2. +Dynamic scaling of particle radius. +EQ.0: Off +EQ.1: On +NP +Number of particles. (Default = 200,000) +UNIT +Unit system: +EQ.0: kg-mm-ms-K +EQ.1: SI +EQ.2: tonne-mm-s-K +EQ.3: User defined units +VISFLG +*AIRBAG_PARTICLE +DESCRIPTION +Visible particles. This field affects only the CPM database. See +Remark 5. +EQ.0: Default to 1 +EQ.1: Output particle's coordinates, velocities, mass, radius, +spin energy, translational energy +EQ.2: Output reduce data set with coordinates only +EQ.3: Suppress CPM database +TATM +PATM +Atmospheric temperature. (Default = 293K) +Atmospheric pressure. (Default = 1 ATM) +NVENT +Number of vent hole parts or part sets +TEND +TSW +Time when all (NP) particles have entered bag. (Default = 1010) +Time at which algorithm switches +(Default = 1010) +to control volumes. +TSTOP +Time at which front tracking switches from IAIR = 4 to IAIR = 2. +TSMTH +OCCUP +REBL +SIDSV +To avoid sudden jumps in the pressure signal during switching +there is a transition period during which the front tracking is +tapered. The default time of 1 millisecond will be applied if this +value is set to zero. +Particles occupy OCCUP percent of the airbag’s volume. The +default value of OCCUP is 10%. This field can be used to balance +computational cost and signal quality. OCCUP ranges from 0.001 +to 0.1. +If the option is ON, all energy stored from damping will be +evenly distributed as vibrational energy to all particles. This +improves the pressure calculation in certain applications. +EQ.0: Off (Default) +EQ.1: On +Part set ID for internal shell part. The volume occupied by this +part is excluded from the bag volume. These internal parts must +be consistently orientated for the excluded volume to be correctly +calculated. +VARIABLE +PSID1 +DESCRIPTION +Part set ID for external parts which have normal pointed +outward. This option is usually used with airbag integrity check +while there are two CPM bags connected with bag interaction. +Therefore, one of the bag can have the correct shell orientation +but the share parts for the second bag will have wrong +orientation. This option will automatically flip the parts defined +in this set in the second bag during integrity checking. +Mass, Time, +Length +Conversion factor from current unit to MKS unit. For example, if +the current unit is using kg-mm-ms, the input should be +1.0, 0.001, 0.001 +IAIR +Initial gas inside bag considered: +EQ.0: No +EQ.1: Yes, using control volume method. +EQ.-1: Yes, using control volume method. In this cake ambient +air enters the bag when PATM is greater than bag pres- +sure. +EQ.2: Yes, using the particle method. +EQ.4: Yes, using the particle method. Initial air particles are +used for the gas front tracking algorithm but they do +not apply forces when they collide with a segment. In- +stead, a uniform pressure is applied to the airbag based +on the ratio of air and inflator particles. In this case +NPRLX must be negative so that forces are not applied +by the initial air. +NGAS +Number of gas components +NORIF +Number of orifices +NID1 - NID3 +Three nodes defining a moving coordinate system for the +direction of flow through the gas inlet nozzles (Default = fixed +system) +CHM +Chamber ID used in *DEFINE_CPM_CHAMBER. See Remark 7. +CD_EXT +Drag coefficient for external air. If the value is not zero, the +inertial effect from external air will be considered and forces will +be applied in the normal direction on the exterior airbag surface. +SIDUP +*AIRBAG_PARTICLE +DESCRIPTION +Part or part set ID defining the internal parts that pressure will be +applied to. This internal structure acts as a valve to control the +external vent hole area. Pressure will be applied only after switch +to UP (uniform pressure) using TSW. +STYUP +Set type: +EQ.0: Part +EQ.1: Part set +PFRAC +LINKING +Fraction of pressure to be applied to the set (0.0 to 1.0). If +PFRAC = 0, no pressure is applied to internal parts. +Part ID of an internal part that is coupled to the external vent +definition. The minimum area of this part or the vent hole will be +used for actual venting area. +SIDH +Part or part set ID defining part data. +STYPEH +Set type: +EQ.0: Part +EQ.1: Part set +HCONV +Heat convection coefficient used to calculate heat loss from the +airbag external surface to ambient (W/K/m2). See *AIRBAG_HY- +BRID developments (Resp. P.O. Marklund). +LT.0: |HCONV| is a load curve ID defines heat convection +coefficient as a function of time. +PFRIC +Friction factor. PFRIC Defaults to FRIC from 1st card 7th field. +SDFBLK +Scale down factor for blockage factor (Default = 1, no scale +down). The valid factor will be (0,1]. If 0, it will set to 1. +KP +INIP +Thermal conductivity of the part. See Remark 9. +Place initial air particles on surface. +EQ.0: yes (default) +EQ.1: no +This feature exclude surfaces from initial particle placement. This +option is useful for preventing particles from being trapped +between adjacent fabric layers. +VARIABLE +DESCRIPTION +SID3 +Part or part set ID defining vent holes. +STYPE3 +Set type: +EQ.0: Part +EQ.1: Part set which each part being treated separately +EQ.2: Part set and all parts are treated as one vent. See Remark +13. + GE..0: Vent hole coefficient, a parameter of Wang-Nefske +leakage. A value between 0.0-1.0 can be input, default = 1.0. See +Remark 1. + LT.0: ID for *DEFINE_CPM_VENT +Load curve defining vent hole coefficient as a function of time. +LCTC23 can be defined through *DEFINE_CURVE_FUNCTION. +If omitted a curve equal to 1 used. See Remark 1. +C23 +LCTC23 +LCPC23 +Load curve defining vent hole coefficient as a function of +pressure. If omitted a curve equal to 1 is used. See Remark 1. +ENH_V +Enhanced venting option. See Remark 8. +EQ.0: Off (default) +EQ.1: On +EQ.2: Two way flow for internal vent; treated as hole for +external vent +Pressure difference between interior and ambient pressure +(PATM) to open the vent holes. Once the vents are open, they +will stay open. +Initial pressure inside bag. (Default PAIR = PATM) +Initial temperature inside bag. (Default, TAIR = TATM) +PPOP +PAIR +TAIR +XMAIR +Molar mass of gas initially inside bag. +AAIR - CAIR +Constant, linear, and quadratic heat capacity parameters. +NPAIR +Number of particle for air. See Remark 6. +*AIRBAG_PARTICLE +DESCRIPTION +NPRLX +Number of cycles to reach thermal equilibrium. See Remark 6. +LT.0: If more than 50% of the collision to fabric is from initial +air particle, the contact force will not apply to the fabric +segment in order to keep its original shape. +If the number contains “.”, “e” or “E”, NPRLX will treated as an +end time rather than as a cycle count. +LCMASS +Total mass flow rate curve for the MOLEFRACTION option. +LCMi +LCTi +XMi +Ai - Ci +INFGi +NIDi +ANi +VDi +flow rate curve +Mass +the +MOLEFRACTION option is used, then it is the time dependent +molar fraction of the total flow for gas component i. +for gas component +i, unless +Temperature curve for gas component i. +Molar mass of gas component i. +Constant, linear, and quadratic heat capacity parameters for gas +component i. +Inflator ID for this gas component (Defaults to 1). +Node ID/Shell ID defining the location of nozzle i. See Remark +12. +Area of nozzle i. (Default: all nozzles are assigned the same area) +GT.0: Vector ID. Initial direction of gas inflow at nozzle 𝑖. +LT.0: Values in the NIDi fields are interpreted as shell IDs. +See Remark 12. +EQ.-1: direction of gas inflow is using shell normal +EQ.-2: direction of gas inflow is in reversed shell normal +CAi +Cone angle in degrees (Defaults to 30 degrees). This option is +used only when IANG equal to 1. +INFOi +Inflator ID for this orifice. (Default = 1) +IMOM +Inflator reaction force (R5.1.1 release and later). +EQ.0: Off +EQ.1: On +VARIABLE +IANG +DESCRIPTION +Activation for cone angle to use for friction calibration(not +normally used; eliminates thermal energy of particles from +inflator). +EQ.0: Off (Default) +EQ.1: On +CHM_ID +Chamber ID where the inflator node resides. Chambers are +defined using the *DEFINE_CPM_CHAMBER keyword. +Remarks: +1. Formula for Total Vent Hole Coefficient. The value must be between 0 and 1. +Total vent hole coefficient = min(max(C23 × LCTC23 × LCPC23, 0), 1) +2. Surface Roughtness. Friction factor to simulate the surface roughness. If the +surface is frictionless the particle incoming angle 𝛼1is equal to the deflection +angle 𝛼2. +Considering surface roughness 𝐹r and the total angle 𝛼 will have the following +relationships: +For the special case when, +0 ≤ 𝐹r ≤ 1 + 𝛼 = 𝛼1 + 𝛼2 +𝐹r = 1 +the incoming particle will bounce back from its incoming direction, + 𝛼 = 0. +For, −1 ≤ 𝐹𝑟 < 0, particles will bounce towards the surface by the following +relationship +𝛼 = 2 [𝛼1 − 𝐹𝑟 ( +− +𝛼1 +)]. +3. Blocking and BLOCK Field. Setting the 10’s digit to 1 allows for physical +holes in an airbag. In this case, particles that are far away from the airbag are +disabled. In most case, these are particles that have escaped through unclosed +surfaces due to physical holes, failed elements, etc. This reduces the bucket sort +search distance. +4. Convection Energy Balance. The change in energy due to convection is given +by +Where, +d𝐸 +d𝑡 += 𝐴 × HCONV × (𝑇bag − 𝑇atm). +𝐴 = is part area. +HCONV = user defined heat convection coefficient. +𝑇bag = the weighted average temperature impacting particles. +𝑇atm = aambient temperature. +5. Output Files. Particle time history data is always output to d3plot database +now. LS-PrePost 2.3 and later can display and fringe this data. In order to +reduce runtime memory requirements, VISFLG should be set to 0 (disabled). +For LS-DYNA 971 R6.1 and later, VISFLG only affects Version 4 CPM output +. +6. Spatial Distribution Equilibration for Airbag Particles. Total number of +particles used in each card is NP + NPAIR. Since the initial air particles are +placed at the surface of the airbag segments with correct velocity distribution +initially, particles are not randomly distributed in space. It requires a finite +number of relaxation cycles, NPRLX, to allow particles to move and produce +better spatial distribution. +Since the momentum and energy transfer between particles are based on per- +fect elastic collision, CPM solver would like to keep similar mole per particle +between inflator and initial air particles. CPM solver will check the following +factor. +factor = ∣1 − +mole per particle of initial air +∣ +mole per particle of inflator gas +If the factor is more than 10% apart, code will issue the warning message with +the tag, (SOL+1232) and provide the suggested NPAIR value. User needs make +decision to adjust the NPAIR value based on the application. For example, user +setup only initial air without any inflator gas for certain impact analysis should +ignore this warning message. +7. Remark Concerning *DEFINE_CPM_CHAMBER. By default initial air +particles will be evenly placed on airbag segments which cannot sense the local +volume. This will create incorrect pressure field if the bag has several distinct +pockets. *DEFINE_CPM_CHAMBER allows the user to initialize air particles +by volume ratios of regions of airbag. The particles will be distributed propor- +tional to the defined chamber volume to achieve better pressure distribution. +8. Enhanced Venting. When enhanced venting is on, the vent hole’s equivalent +radius 𝑅eq will be calculated. Particles within 𝑅eq on the high pressure side +from the vent hole geometry center will be moved toward the hole. This will +increase the collision frequency near the vent for particles to detect small struc- +tural features and produce better flow through the vent hole. +ENH_V equals 1, particles are flow from high to low pressure only. EHN_V +equals 2, particles can flow in both directions for internal vent. +Particles encountering external vents are released. The ambient pressure is not +taken into account and the particle will be released regardless the value of the +pressure in the bag/chamber. Therefore, the vent rate will be sensitive to the +vent location. +9. Effective Convection Heat Transfer Coefficient. If the thermal conductivity, +KP, is given, then the effective convection heat transfer coefficient is given by +𝐻eff = ( +1.0 +HCONV ++ +shell thickness +KP +) +−1 +, +where the part thickness comes from the SECTION database. If KP is not given, +𝐻eff defaults to HCONV. +10. MOLEFRACTION Option. Without the MOLEFRACTION option, a flow rate +is specified for each species on the LCMi fields of Card 11. With the MOLE- +FRACTION option the total mass flow rate is specified in the LCMASS field on +Card 10 and the molar fractions are specified in the LCMi fields of Card +11. +11. User Defined Units. If UNIT = 3 is used, there is no default value for TATM +and PATM and user should provide the proper values. User also needs to +provide unit conversion factors for code to set correct universal gas constant +and some other variables used in the code. +12. Shell Based Nozzle. Node ID and shell ID based nozzle should not be used in +the same airbag definition. The nozzle location is taken to be at the center of the +shell and the initial nozzle direction can be defined by shell’s normal or by its +reversed normal. This vector is transforms with the moving coordinate system +defined by NID1 - NID3. The nozzle area is set on the ANi fields and shell area +is not taken into account; therefore, the mass flowrate distribution with shells is +determined in the same way as it is with nozzles defined by nodes. +13. Merge Part Set for Vent. The first part in the set is designated as the master. +All remaining parts are merged into the master so that enhanced venting is +treated correctly. ABSTAT_CPM output will be associated with the master +part. This option has the same effect as manually merging elements into the +master part. +*AIRBAG_REFERENCE_GEOMETRY_{OPTION}_{OPTION}_{OPTION} +Available options include: + +BIRTH +RDT +ID +Purpose: If the reference configuration of the airbag is taken as the folded configura- +tion, the geometrical accuracy of the deployed bag will be affected by both the +stretching and the compression of elements during the folding process. Such element +distortions are very difficult to avoid in a folded bag. By reading in a reference +configuration such as the final unstretched configuration of a deployed bag, any +distortions in the initial geometry of the folded bag will have no effect on the final +geometry of the inflated bag. This is because the stresses depend only on the +deformation gradient matrix: +𝐹𝑖𝑗 = +∂𝑥𝑖 +∂𝑋𝑗 +where the choice of 𝑋𝑗 may coincide with the folded or unfold configurations. It is this +unfolded configuration which may be specified here. +Note that a reference geometry which is smaller than the initial airbag geometry will +not induce initial tensile stresses. +If a liner is included and the parameter LNRC set to 1 in *MAT_FABRIC, compression is +disabled in the liner until the reference geometry is reached, i.e., the fabric element +becomes tensile. +When the BIRTH option is specified an additional card setting the BIRTH parameter is +activated. The BIRTH parameter specifies a critical time value before which the +reference geometry is not used. Until the BIRTH time is reach the input geometry is +used for (1) inflating the airbag and for (2) determining the time step size, even when +the RDT option is set. +NOTE: This card does not support multiple birth times. The +last BIRTH value read will be used for all preceding +*AIRBAG_REFERENCE_GEOMETRY_BIRTH defini- +tions. RGBRTH in *MAT_FABRIC supports a mate- +rial dependent birth time. +When the RDT option is active the time step size will be based on the reference +geometry once the solution time exceeds the birth time. This option is useful for +shrunken bags where the bag does not carry compressive loads and the elements can +freely expand before stresses develop. If this option is not specified, the time step size +will be based on the current configuration and will increase as the area of the elements +increase. The default may be much more expensive but possibly more stable. +ID card. Additional card for keyword option ID. +ID +Variable +1 +ID +Type +I +2 +SX +F +3 +SY +F +4 +SZ +F +5 +6 +7 +8 +NIDO +I +Default +none +1.0 +1.0 +1.0 +1st NID +Birth card. Additional card for keyword option BIRTH. +Birth +1 +2 +3 +4 +5 +6 +7 +8 +Variable +BIRTH +Type +F +Default +0.0 +Node Cards. For each node ID having an associated reference position include an +additional card in format 2. The next “*” keyword card terminates this input. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +Variable +NID +Type +I +X +F +Default +none +0. +Remark +Y +F +0. +Z +F +0. + VARIABLE +DESCRIPTION +ID +Card ID +SX, SY, SZ +Scale factor in each direction +NIDO +Node ID for origin. Default is the first node ID defined in this +keyword. +BIRTH +Time at which the reference geometry activates (default = 0.0) +NID +X +Y +Z +Node ID for which a reference configuration is defined. Nodes +defined in this section must also appear under the *NODE input. +It is only necessary to define the reference coordinates of nodal +points, if their coordinates are different than those defined in the +*NODE section. +𝑥 coordinate +𝑦 coordinate +𝑧 coordinate +*AIRBAG_SHELL_REFERENCE_GEOMETRY_{OPTION}_{OPTION} +Available options include: + +RDT +ID +Purpose: Usually, the input in this section is not needed; however, sometimes it is +convenient to use disjoint pre-cut airbag parts to define the reference geometries. If the +reference geometry is based only on nodal input, this is not possible since in the +assembled airbag the boundary nodes are merged between parts. By including the shell +connectivity with the reference geometry, the reference geometry can be based on the +pre-cut airbag parts instead of the assembled airbag. The elements, which are defined +in this section, must have identical element ID’s as those defined in the *ELEMENT_- +SHELL input, but the nodal ID’s, which may be unique, are only used for the reference +geometry. These nodes are defined in the *NODE section but can be additionlly +defined in *AIRBAG_REFERENCE_GEOMETRY. The element orientation and n1-n4 +ordering must be identical to the *ELEMENT_SHELL input. +When the RDT option is active the time step size will be based on the reference +geometry once the solution time exceeds the birth time which can be defined by +RGBRTH of *MAT_FABRIC. +ID card. Additional card for keyword option ID. + Card 1 +Variable +1 +ID +Type +I +2 +SX +F +3 +SY +F +4 +SZ +F +5 +NID +I +Default +none +1.0 +1.0 +1.0 +See List +6 +7 +Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +Variable +EID +PID +N1 +N2 +N3 +N4 +Type +I +I +I +I +I +I +Default +none none none none none none + VARIABLE +DESCRIPTION +ID +Card ID +SX, SY, SZ +Scale factor in each direction +NID +EID +PID +N1 +N2 +N3 +N4 +Node ID for origin. Default is the first node ID defined in this +keyword. +Element ID +Optional part ID, see *PART, the part ID is not used in this +section. +Nodal point 1 +Nodal point 2 +Nodal point 3 +Nodal point 4 +ALE does not support implicit time integration nor does it support dynamic relaxation. +Furthermore, except for ALE formulation 5, which does support contact, ALE does not, in +general, support contact. +In three dimensions, ALE supports only one-point solid elements. These solid elements +can either be hexahedral, pentahedral, or tetrahedral. Pentahedrons and tetrahedrons +are treated as degenerate hexahedron elements. For each ALE multi-material, strain +and stress is evaluated in each solid element at a single integration point. In this sense, +the ALE element formulation is equivalent to ELEFORM 1 solid formulation. +Keywords for the ALE structured solver. +*ALE_STRUCTURED_MESH +*ALE_STRUCTURED_MESH_CONTROL_POINTS +Input required for LS-DYNA’s Arbitrary-Lagrangian-Eulerian capability is defined +using *ALE cards. The keyword cards in this section are defined in alphabetical order: +*ALE_AMBIENT_HYDROSTATIC +*ALE_COUPLING_NODAL_CONSTRAINT +*ALE_COUPLING_NODAL_DRAG +*ALE_COUPLING_NODAL_PENALTY +*ALE_COUPLING_RIGID_BODY +*ALE_ESSENTIAL_BOUNDARY +*ALE_FAIL_SWITCH_MMG +*ALE_FRAGMENTATION +*ALE_FSI_PROJECTION +*ALE_FSI_SWITCH_MMG_{OPTION} +*ALE_FSI_TO_LOAD_NODE +*ALE_MULTI-MATERIAL_GROUP +*ALE_REFERENCE_SYSTEM_CURVE +*ALE_REFERENCE_SYSTEM_NODE +*ALE_REFERENCE_SYSTEM_SWITCH +*ALE_REFINE +*ALE_SMOOTHING +*ALE_TANK_TEST +*ALE_UP_SWITCH +For other input information related to the ALE capability, see keywords: +*ALE_TANK_TEST +*BOUNDARY_AMBIENT_EOS +*CONSTRAINED_EULER_IN_EULER +*CONSTRAINED_LAGRANGE_IN_SOLID +*CONTROL_ALE +*DATABASE_FSI +*INITIAL_VOID +*INITIAL_VOLUME_FRACTION +*INITIAL_VOLUME_FRACTION_GEOMETRY +*SECTION_SOLID +*SECTION_POINT_SOURCE_FOR_GAS_ONLY +*SECTION_POINT_SOURCE_MIXTURE +*SET_MULTIMATERIAL_GROUP_LIST +*CONSTRAINED_EULER_IN_EULER +For a single gaseous material: +*EOS_LINEAR_POLYNOMIAL +*EOS_IDEAL_GAS +For multiple gaseous materials: +*MAT_GAS_MIXTURE +*INTIAL_GAS_MIXTURE +*ALE_AMBIENT_HYDROSTATIC +Purpose: When an ALE model contains one or more ambient (or reservoir-type) ALE +parts (ELFORM = 11 and AET = 4), this command may be used to initialize the +hydrostatic pressure field in the ambient ALE domain due to gravity. The *LOAD_- +BODY_{OPTION} keyword must be defined. The associated *INITIAL_HYDROSTAT- +IC_ALE keyword may be used to define a similar initial hydrostatic pressure field for +the regular ALE domain (not reservoir-type region). + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ALESID +STYPE +VECID +GRAV +PBASE RAMPTLC +Type +I +Default +none + Card 2 +1 +I +0 +2 +I +none +3 +I +0 +4 +I +0 +5 +I +0 +6 +7 +8 +Variable +NID +MMGBL +Type +I +I +Default +None +none + VARIABLE +ALESID +DESCRIPTION +ALESID defines the reservoir-type ALE domain/mesh whose +hydrostatic pressure field due to gravity is being initialized by +this keyword. See Remark 4. +STYPE +ALESID set type. See Remark 4. +EQ.0: Part set ID (PSID), +EQ.1: Part ID (PID) ), +EQ.2: Solid set ID (SSID). +VECID +Vector ID of a vector defining the direction of gravity. +VARIABLE +DESCRIPTION +GRAV +PBASE +Magnitude of the Gravitational acceleration. For example, in +metric units the value is usually set to 9.80665 m/s2. +Nominal or reference pressure at the top surface of all fluid +layers. By convention, the gravity direction points from the top +layer to the bottom layer. Each fluid layer must be represented by +an ALE multi-material group ID (AMMGID or MMG). See +Remark 1. +RAMPTLC +A ramping time function load curve ID. This curve (via *DE- +FINE_CURVE) defines how gravity is ramped up as a function of +time. Given GRAV value above, the curve’s ordinate varies from +0.0 to 1.0, and its abscissa is the (ramping) time. See Remark 2. +NID +Node ID defining the top of an ALE fluid (AMMG) layer. +MMGBL +AMMG ID of the fluid layer immediately below this NID. Each +node is defined in association with one AMMG layer below it. +See Remark 4. +Remarks: +1. Pressure in Multi-Layer Fluids. For models using multi-layer ALE Fluids the +pressure at the top surface of the top fluid layer is set to PBASE and the hydro- +static pressure is computed as following +𝑁layers +𝑃 = 𝑃base + ∑ 𝜌𝑖𝑔ℎ𝑖 + . +𝑖=1 +2. Hydrostatic Pressure Ramp Up. If RAMPTLC is activated (i.e. not equal to +“0”), then the hydrostatic pressure is effectively ramped up over a user-defined +duration and kept steady. When this load curve is defined, do not define the +associated *INITIAL_HYDROSTATIC_ALE card to initialize the hydrostatic +pressure for the non-reservoir ALE domain. The hydrostatic pressure in the +regular ALE region will be initialized indirectly as a consequence of the hydro- +static pressure generated in the reservoir-type ALE domain. The same load +curve should be used to ramp up gravity in a corresponding *LOAD_- +BODY_(OPTION) card. Via this approach, any submerged Lagrangian struc- +ture coupled to the ALE fluids will have time to equilibrate to the proper +hydrostatic condition. +3. Limitation on EOS Model. The keyword only supports *EOS_GRUNEISEN +and *EOS_LINEAR_POLYNOMIAL, but only inthe following two cases, +𝑐4 = 𝑐5 > 0, +𝑐3 = 𝑐4 = 𝑐5 = 𝑐6 = 0, +𝑐1 = 𝑐2 = 𝑐3 = 𝑐6 = 0, +𝐸0 = 0 +𝑉0 = 0. +4. Structured ALE usage. When used with structured ALE, PART and PART +set options might not make too much sense. This is because all elements inside +a structured ALE mesh are assigned to one single PART ID. In the Structured +ALE case, we should generate a solid set which contains those ALE boundary +elements we want to prescribe hydrostatic pressures on. It is done by using the +*SET_SOLID_GENERAL keyword with SALECPT option. And then use the +STYPE=2 option (Solid element set ID). +Example: +Model Summary: Consider a model consisting of 2 ALE parts, air on top of water. +H3 = AMMG1 = Air part above +H4 = AMMG2 = Water part below +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +$ ALE materials (fluids) listed from top to bottom: +$ +$ NID AT TOP OF A LAYER SURFACE ALE MATERIAL LAYER BELOW THIS NODE +$ TOP OF 1st LAYER -------> 1681 ---------------------------------------- +$ Air above = PID 3 = H3 = AMMG1 (AET=4) +$ TOP OF 2nd LAYER -------> 1671 ---------------------------------------- +$ Water below = PID 4 = H4 = AMMG2 (AET=4) +$ BOTTOM --------------------> ---------------------------------------- +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*ALE_AMBIENT_HYDROSTATIC +$ ALESID STYPE VECID GRAV PBASE RAMPTLC + 34 0 11 9.80665 101325.0 9 +$ NID MMGBL + 1681 1 + 1671 2 +*SET_PART_LIST + 34 + 3 4 +*ALE_MULTI-MATERIAL_GROUP + 3 1 + 4 1 +*DEFINE_VECTOR +$ VID XT YT ZT XH YH ZH CID + 11 0.0 1.0 0.0 0.0 0.0 0.0 +*DEFINE_CURVE + 9 + 0.000 0.000 + 0.001 1.000 + 10.000 1.000 +*LOAD_BODY_Y +$ LCID SF LCIDDR XC YC ZC + 9 9.80665 0 0.0 0.0 0.0 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*ALE_COUPLING_NODAL_CONSTRAINT_{OPTION} +Available options include: + +ID +TITLE +Purpose: This keyword activates constraint coupling between ALE materials (master) +and non-ALE nodes. The slave nodes may belong to Lagrangian solid, shell, beam, +thick shell, or discrete sphere elements. In +contrast to *ALE_COUPLING_NODAL_PENALTY, caution should be exercised in +connection with EFG and SPH nodes, as meshless methods generally do not satisfy +essential boundary conditions, leading to energy dissipation. +This keyword requires a 3D ALE formulation. It is, there- +fore, incompatible with parts defined using *SECTION_- +ALE2D or *SECTION_ALE1D. +If a title is not defined LS-DYNA will automatically create an internal title for this +coupling definition. +Title Card. Additional card for TITLE and ID keyword options. +Title +1 +2 +3 +4 +5 +6 +7 +8 +Variable +COUPID +Type +I +TITLE +A70 + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SLAVE MASTER +SSTYP +MSTYP +CTYPE +MCOUP +Type +I +I +Default +none +none +I +0 +I +0 +I +1 +I +Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +START +END +Type +Default +F +0 +F +1.0E10 +FRCMIN +F +0.5 + VARIABLE +COUPID +DESCRIPTION +Coupling (card) ID number (I10). If not defined, LSDYNA will +assign an internal coupling ID based on the order of appearance +in the input deck. +TITLE +A description of this coupling definition (A70). +SLAVE +Slave set ID defining a part, part set or segment set ID of the +Lagrangian or slave structure . See Remark 1. +MASTER +Master set ID defining a part or part set ID of the ALE or master +solid elements . +SSTYP +Slave set type of “SLAVE”: +EQ.0: part set ID (PSID). +EQ.1: part ID (PID). +EQ.2: segment set ID (SGSID). +EQ.3: node set ID (NSID). +MSTYP +Master set type of “MASTER”: +EQ.0: part set ID (PSID). +EQ.1: part ID (PID). +CTYPE +Coupling type: +EQ.1: constrained velocity only. +EQ.2: constrained acceleration and velocity. +MCOUP +Multi-material option . +EQ.0: couple with all multi-material groups, +VARIABLE +DESCRIPTION +LT.0: MCOUP must be an integer. –MCOUP refers to a set ID +of an ALE multi-material groups defined in *SET_MUL- +TI-MATERIAL_GROUP. +START +Start time for coupling. +END +End time for coupling. +FRCMIN +Only to be used with nonzero MCOUP. Minimum volume +fraction of the fluid materials included in the list of AMMGs to +activate coupling. Default value is 0.5. +Remarks: +When MCOUP is a negative integer, say for example MCOUP = -123, then an ALE +multi-material set-ID (AMMSID) of 123 must exist. This is an ID defined by a *SET_- +MULTI-MATERIAL_GROUP_LIST card. +*ALE_COUPLING_NODAL_DRAG +Available options include: + +ID +TITLE +Purpose: This command provides a coupling mechanism to model the drag interaction +between ALE fluids, which provide the master elements, and discrete element forms, +which comprise the slave nodes. The slave nodes are assumed to be of spherical shape +being either SPH elements, or discrete elements (*ELEMENT_DISCRETE_SPHERE). +The coupling forces are proportional to the relative speed between the fluid and +particles plus the buoyancy force due to gravitational loading. +This keyword requires a 3D ALE formulation. It is, there- +fore, incompatible with parts defined using *SECTION_- +ALE2D or *SECTION_ALE1D. +If a title is not defined, LS-DYNA will automatically generate an internal title for this +coupling definition. +Title Card. Additional card for TITLE and ID keyword options. +Title +1 +2 +3 +4 +5 +6 +7 +8 +Variable +COUPID +Type +I +TITLE +A70 + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SLAVE MASTER +SSTYP +MSTYP +Type +I +I +Default +none +none +I +0 +I +Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +START +END +FCOEF +DIRECG +GRAV +Type +Default +F +0 +F +1.0E10 +F +1.0 +I +F +none +0.0 + VARIABLE +COUPID +DESCRIPTION +Coupling (card) ID number (I10). If not defined, LSDYNA will +assign an internal coupling ID based on the order of appearance +in the input deck. +TITLE +A description of this coupling definition (A70). +SLAVE +Slave set ID defining a part, part set or segment set ID of the +Lagrangian or slave structure . +MASTER +Master set ID defining a part or part set ID of the ALE or master +solid elements . +SSTYP +Slave set type of “SLAVE”: +EQ.0: part set ID (PSID). +EQ.1: part ID (PID). +EQ.2: segment set ID (SGSID). +EQ.3: node set ID (NSID). +MSTYP +Master set type of “MASTER”: +EQ.0: part set ID (PSID). +EQ.1: part ID (PID). +START +Start time for coupling. +END +End time for coupling. +FCOEF +*ALE_COUPLING_NODAL_DRAG +DESCRIPTION +Drag coefficient scale factor or function ID to calculate drag +coefficient +GT.0: Drag coefficient scale factor. +LT.0: The absolute value of FCOEF is the Function ID of the +user provided function to calculate drag coefficient; See +Remark 1. +DIRECG +Gravity force direction. +EQ.1: Global x direction +EQ.2: Global y direction +EQ.3: Global z direction +GRAV +Gravity value. This value is used to calculate buoyance force. +Remarks: +1. Drag Coupling Force. The drag coupling force in between the particles and +ALE fluids takes the following form. +𝐹drag = 𝑐drag × 1 +𝜌𝑣2 × 1 +𝜋𝑑2 +where 𝑐drag is the drag coefficient, 𝜌 the fluid density in which the particle is +submerged, 𝑣 the relative velocity between the particle and the fluid, 𝑑 the +diameter of the particle. +The default drag coefficient is a function of Reynolds’s number and calculated +by using the following formula: +𝑐drag = +⎜⎛0.63 + +⎝ +. +4.8 +⎟⎞ +√Re⎠ +Users can define their own function of drag coefficient. To do that, one needs to +define a function using *DEFINE_FUNCTION and assign the negative function +ID to FCOEF flag. +An example is provided below to illustrate the setup. It is equivalent to the +default drag coefficient calculation. +*ALE_COUPLING_NODAL_DRAG + 10001 1 3 1 + -10 3 9.81 +*DEFINE_FUNCTION + 10 +float cd(float re) +{ + float cd; + cd=(0.63+4.8/sqrt(re))*(0.63+4.8/sqrt(re)); + if (cd > 2.0) cd = 2.0; + return cd; +} +*ALE_COUPLING_NODAL_PENALTY +Available options include: + +ID +TITLE +Purpose: This command provides a penalty coupling mechanism between ALE +materials (master) and non-ALE nodes (slave). The slave nodes may belong to +Lagrangian solid, shell, beam, thick shell, or discrete (*ELEMENT_DISCRETE_SPHERE) +elements. In contrast to *ALE_COUPLING_NODAL_CONSTRAINT, SPH and EFG +nodes are supported. +This keyword is incompatible with parts that use *SEC- +TION_ALE2D or *SECTION_ALE1D, i.e., it requires a 3D +ALE formulation. +If a title is not defined LS-DYNA will automatically create an internal title for this +coupling definition. +Title Card. Additional card for TITLE and ID keyword options. +Title +1 +2 +3 +4 +5 +6 +7 +8 +Variable +COUPID +Type +I +TITLE +A70 + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SLAVE MASTER +SSTYP +MSTYP +MCOUP +Type +I +I +Default +none +none +I +0 +I +0 +I +Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +START +END +PFORM +PFAC +FRCMIN +Type +Default +F +0 +F +1.0E10 +I +0 +F +0.1 +F +0.5 + VARIABLE +COUPID +DESCRIPTION +Coupling (card) ID number (I10). If not defined, LSDYNA will +assign an internal coupling ID based on the order of appearance +in the input deck. +TITLE +A description of this coupling definition (A70). +SLAVE +Slave set ID defining a part, part set or segment set ID of the +Lagrangian or slave structure . See Remark 1. +MASTER +Master set ID defining a part or part set ID of the ALE or master +solid elements . +SSTYP +Slave set type of “SLAVE”: +EQ.0: part set ID (PSID). +EQ.1: part ID (PID). +EQ.2: segment set ID (SGSID). +EQ.3: node set ID (NSID). +MSTYP +Master set type of “MASTER”: +EQ.0: part set ID (PSID). +EQ.1: part ID (PID). +MCOUP +Multi-material option . +EQ.0: couple with all multi-material groups, +LT.0: MCOUP must be an integer. –MCOUP refers to a set ID +of an ALE multi-material groups defined in *SET_MUL- +TI-MATERIAL_GROUP. +START +Start time for coupling. +VARIABLE +DESCRIPTION +END +End time for coupling. +PFORM +Penalty stiffness formulations. +EQ.0: mass based penalty stiffness. +EQ.1: bulk modulus based penalty stiffness. +EQ.2: penalty stiffness is determined by the user-provided load +curve between penetration and penalty pressure. +Penalty stiffness factor (PFORM = 0 or 1) for scaling the estimated +stiffness of the interacting (coupling) system or Load Curve ID +(PFORM = 2). +Only to be used with nonzero MCOUP. Minimum volume +fraction of the fluid materials included in the list of AMMGs to +activate coupling. Default value is 0.5. +PFAC +FRCMIN +Remarks: +When MCOUP is a negative integer, say for example MCOUP = -123, then an ALE +multi-material set-ID (AMMSID) of 123 must exist. This is an ID defined by a *SET_- +MULTI-MATERIAL_GROUP_LIST card. +*ALE +Purpose: This command serves as a simplified constraint type coupling method +between ALE fluids and a Lagrange rigid body. +In certain FSI simulations structure deformation is either small or not of the interest. +Often times these structures are modeled as rigid bodies to shorten the simulation time +and reduce the complexity. For such kind of problems, a full scale ALE/FSI simulation +is costly in both simulation time and memory. This keyword provides a light-weight +alternative FSI method for systems with minimal structural response. +It has a similar input format to *ALE_ESSENTIAL_BOUNDARY and maybe regarded +as being an extension of the essential boundary feature. The documentation for *ALE_- +ESSENTIAL_BOUNDARY_BODY applies, in large part, to this card also. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IPID +NSID +Type +I +I +Default +none +none +ALE Coupling Interfaces Cards. Include one card for each part, part set or segment to +define ALE coupling interface. This input ends at the next keyword (“*”) card. + Card 2 +Variable +1 +ID +2 +3 +4 +5 +6 +7 +8 +IDTYPE +ICTYPE +IEXCL +Type +I +I +Default +none +none +I +1 +I +none + VARIABLE +DESCRIPTION +IPID +NSID +Rigid body part ID. +Node set ID defining ALE boundary nodes to follow Rigid body +motion. +VARIABLE +DESCRIPTION +ID +Set ID defining a part, part set or segment set ID of the ALE +coupling interface. +IDTYPE +Type of set ID: +EQ.0: part set ID (PSID). +EQ.1: part ID (PID). +EQ.2: segment set ID (SGSID). +ICTYPE +Constraint type: +EQ.1: No flow through all directions. +EQ.2: No flow through normal direction. (slip condition) +IEXCL +Segment Set ID to be excluded from applying ALE essential +boundary condition. For example, inlet/outlet segments. +Remarks: +For ICTYPE = 2, the constrained direction(s) at each surface node comes in part from +knowing whether the node is a surface node, an edge node, or a corner node. If the +ALE mesh boundary is identified by part(s) (IDTYPE = 0/1), edge and corner nodes are +automatically detected during the segment generation process. + However, this +automatic detection is not foolproof for complicated geometries. Identifying the ALE +mesh boundary using segment sets (IDTYPE = 2) is generally preferred for complicated +geometries in order to avoid misidentification of edge and corner nodes. When +segment sets are used, the edge and corner nodes are identified by their presence in +multiple segment sets where each segment set describes a more or less smooth, +continuous surface. The intersections of these surfaces are used to identify edge/corner +nodes. +*ALE +Purpose: This command applies and updates essential boundary conditions on ALE +boundary surface nodes. Updating the boundary conditions is important if the ALE +mesh moves according to *ALE_REFERENCE_SYSTEM_GROUP. If the mesh does not +move, it’s more correct to call it an Eulerian mesh rather than an ALE mesh, but *ALE_- +ESSENTIAL_BOUNDARY can be applied nonetheless. +Certain engineering problems need to constrain the flow along the ALE mesh +boundary. A simple example would be water flowing in a curved tube. Using the +*ALE_ESSENTIAL_BOUNDARY approach, the tube material is not modeled and there +is no force coupling between the fluid and the tube, rather the interior volume of the +tube is represented by the location of the ALE mesh. Defining SPC boundary +conditions with a local coordinate system at each ALE boundary node would be +extremely inconvenient in such a situation. The *ALE_ESSENTIAL_BOUNDARY +command applies the desired constraints along the ALE surface mesh automatically. +The user only needs to specify the part(s) or segment set(s) corresponding to the ALE +boundary surfaces and the type of constraint desired. +Boundary Condition Cards. Include one card for each part, part set or segment on +which essential boundary conditions are applied. This input ends at the next keyword +(“*”) card. + Card 1 +Variable +1 +ID +2 +3 +4 +5 +6 +7 +8 +IDTYPE +ICTYPE +IEXCL +Type +I +I +Default +none +none +I +1 +I +none + VARIABLE +DESCRIPTION +ID +Set ID defining a part, part set or segment set ID of the ALE mesh +boundary. +IDTYPE +Type of set ID: +EQ.0: part set ID (PSID). +EQ.1: part ID (PID). +EQ.2: segment set ID (SGSID). +VARIABLE +DESCRIPTION +ICTYPE +Constraint type: +EQ.1: No flow through all directions. +EQ.2: No flow through normal direction. (slip condition) +IEXCL +Segment Set ID to be excluded from applying ALE essential +boundary condition. For example, inlet/outlet segments. +Remarks: +For ICTYPE = 2, the constrained direction(s) at each surface node comes in part from +knowing whether the node is a surface node, an edge node, or a corner node. If the +ALE mesh boundary is identified by part(s) (IDTYPE = 0/1), edge/corner nodes are +automatically detected during the segment generation process. + However, this +automatic detection is not foolproof for complicated geometries. Identifying the ALE +mesh boundary using segment sets (IDTYPE = 2) is generally preferred for complicated +geometries in order to avoid misidentification of edge/corner nodes. When segment +sets are used, the edge/corner nodes are identified by their presence in multiple +segment sets where each segment set describes a more or less smooth, continuous +surface. In short, the junctures or intersections of these surfaces identify edge/corner +nodes. +*ALE +Purpose: This card is used to allow the switching of an ALE multi-material-group ID +(AMMGID) if a failure criteria is reached. If this card is not used and *MAT_VACUUM +has a multi-material group in the input deck, failed ALE groups are replaced by the +group for *MAT_VACUUM. +Available options include: + +ID +TITLE +A title for the card may be input between the 11th and 80th character on the title-ID line. +The optional title line precedes all other cards for this command. +The user can explicitly define a title for this coupling. +Title Card. Additional card for the ID or TITLE options to keyword. +Title +Variable +1 +ID +Type +I10 +2 +3 +4 +5 +6 +7 +8 +TITLE +A70 + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FR_MMG TO_MMG +Type +I +I +Default +none +none + VARIABLE +FR_MMG +DESCRIPTION +This is the AMMG-SID before the switch. The AMMG-SID +corresponds to the SID defined under the *SET_MULTI-MATERI- +AL_GROUP_LIST (SMMGL) card. This SID points to one or +more AMMGs. See Remark 1. +This is the AMMG-SID after the switch. The AMMG-SID +corresponds to the SID defined under the *SET_MULTI-MATERI- +AL_GROUP_LIST card. This SID points to one or more AMMGs. +See Remark 1. +*ALE + VARIABLE +TO_MMG +Remarks: +1. There is a correspondence between the FR_MMG and TO_MMG. Consider an +example where: +a) The FR_MMG SID points to a SID = 12 (the SID of its SMMGL card is 12, +and this SID contains AMMG 1 and AMMG 2) +b) The TO_MMG points to a SID = 34 (the SID of the SMMGL card is 34, and +this SID contains AMMG 3 and AMMG 4) +Then, AMMG 1, if switched, will become AMMG 3, and AMMG 2, if switched, +will become AMMG 4. +*ALE +Purpose: When a material fails, this card is used to switch the failed material to + When used with FRAGTYP = 2, it can be used to model material +vacuum. +fragmentation. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FR_MMG TO_MMG FRAGTYP +Type +I +I +I +Default +none +none +none +DESCRIPTION +This is the AMMGID of the material that just fails, before the +switch. +This is the AMMGID of the vacuum that the failed material is +being switched to. +Flag defining whether the failed material is completely or +partially switched to vacuum . +EQ.1: Fully switch; all failed material is switched to vacuum. +EQ.2: Partially switch; only the volume expansion from the last +time step is switched to vacuum. + VARIABLE +FR_MMG +TO_MMG +FRAGTYP +Remarks: +The Lagrange element contains only one material. Once the failure criterion is met in a +Lagrange element, the whole element is marked as “failed” and either deleted or kept +from further element force calculation. +However, for multi-material ALE elements, such approach is not practical as these +elements are occupied by multiple materials. Failure, therefore, cannot be adequately +modeled at the element level. Instead we convert the failed material inside an ALE +element to vacuum. The effect is similar to element deletion in Lagrange simulations. +The failed material, once switched to vacuum, is excluded from any future element +force calculation. +1. Switch to Vacuum, (FRAGTYPE = 1). By default multi-material elements +switch failed materials to vacuum. This switch involves assigning the full vol- +ume fraction of the failed material, say AMMG 1, in an element to vacuum, say +AMMG 2. +FRAGTYP = 1 is equivalent to the default treatment. However, with this card +the vacuum AMMG can be explicitly specified. In the case that more than one +vacuum AMMG exist, it is strongly recommended to use the FRAGTYP = 1 +approach to eliminate ambiguity. It is also helpful during post-processing since +it is possible to see the material interface of the switched material by assigning a +dedicated vacuum AMMG to the switched material. +2. Fragmentation, (FRAGTYPE = 2). FRAGYP = 2 models material fragmenta- +tion. Note that the FRAGTYP = 1 approach leads to loss of mass and, conse- +quently, dissipates both momentum and energy. With FRAGTYP = 2, instead +of converting the full volume of the failed material to vacuum, LS-DYNA only +converts the material expansion to vacuum. This approach conserves mass and, +therefore, momentum and energy. +To illustrate how this fragmentation model works, consider a tension failure +example. At the time step when the material fails, LS-DYNA calculates the +material expansion in the current step and converts this volume to vacuum. +The stresses and other history variables are left unchanged, so that in the next +time step it will again fail. The expansion in the next time step will be also +converted to vacuum. This process continues until maybe at a later time the +gap stops growing or even starts to close due to compression. +Example: +Consider a simple bar extension example: +FR_MMG: H5 = AMMG1 = Metal bar + H6 = AMMG2 = Ambient air +TO_MMG: H7 = AMMG3 = Dummy vacuum part +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*ALE_FRAGMENTATION +$ FR_MMG TO_MMG FRAGTYP + 1 3 2 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*ALE +Purpose: This card provides a coupling method for simulating the interaction between +a Lagrangian material set (structure) and ALE material set (fluid). The nearest ALE +nodes are projected onto the Lagrangian structure surface at each time step. This +method does not conserve energy, as mass and momentum are transferred via +constrained based approach. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LAGSID +ALESID +LSIDTYP ASIDTYP SMMGID +ICORREC +INORM +I +0 +3 +I +0 +4 +I +0 +5 +I +0 +6 +I +0 +7 +8 +Type +Default +I +0 + Card 2 +1 +I +0 +2 +Variable +BIRTH +DEATH +Type +F +F +Default +0.0 +1.E+10 + VARIABLE +LAGSID +DESCRIPTION +A set ID defining the Lagrangian part(s) for this coupling +(structures). +ALESID +A set ID defining the ALE part(s) for this coupling (fluids). +LSIDTYP +Lagrangian set ID type +EQ.0: Part set ID (PSID), +EQ.1: Part ID (PID). +ASIDTYP +ALE set ID type +EQ.0: Part set ID (PSID), +EQ.1: Part ID (PID). +SMMGID +*ALE_FSI_PROJECTION +DESCRIPTION +A set ID referring to a group of one or more ALE-Multi-Material- +Group (AMMG) IDs which represents the ALE materials +interacting with the Lagrangian structure. This SMMGID is a set +ID defined by *SET_MULTI-MATERIAL_GROUP_LIST. +ICORREC +Advection error correction method . +EQ.1: ALE mass is conserved. Leaked mass is moved, +EQ.2: ALE mass is almost conserved, +EQ.3: No correction performed (default). +is +conserved. Some leakage may occur. This may be the +best solution. + ALE mass +INORM +Type of coupling. +EQ.0: Couple in all directions, +EQ.1: Couple in compression and tension (free sliding), +EQ.2: Couple in compression only (free sliding). This choice +requires ICORREC = 3. +BIRTH +Start time for coupling. +DEATH +End time for coupling. +Remarks: +1. As the ALE nodes are projected onto the closest Lagrangian surface, there may +be some advection errors introduced. These errors may result in a small ele- +ment mass fraction being present on the “wrong” side of the coupled Lagrangi- +an surface. There are 3 possible scenarios: +a) Mass on the wrong side of the Lagrangian structure may be moved to the +right side. This may cause P oscillations. No leakage will occur. +b) Mass on the wrong side is deleted. Mass on the right side is scaled up to +compensate for the lost mass. No leakage will occur. +c) Mass on the wrong side is allowed (no correction performed). Some leak- +age may occur. This may be the most robust and simplest approach. +Model Summary: +*ALE +H1 = AMMG1 = background air mesh +H2 = AMMG1 = background air mesh +S3 = cylinder containing AMMG2 +S4 = dummy target cylinder for impact +The gas inside S3 is AMMG2. S3 is given an initial velocity and it will impact S4. +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*ALE_MULTI-MATERIAL_GROUP + 1 1 + 2 1 +*SET_MULTI-MATERIAL_GROUP_LIST + 22 + 2 +*ALE_FSI_PROJECTION +$ LAGSID ALESID LSIDTYP ASIDTYP SMMGID ICORREC INORM + 3 1 1 1 22 3 2 +$ BIRTH DEATH + 0.0 20.0 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*ALE_FSI_SWITCH_MMG +Purpose: This card is used to allow the switching of an ALE multi-material-group ID +(AMMGID) of a fluid as that fluid passes across a monitoring surface. This monitoring +surface may be a Lagrangian shell structure, or a segment set. It does not have to be +included in the slave set of the coupling card: *CONSTRAINED_LAGRANGE_IN_SOL- +ID. However, at least one coupling card must be present in the model. +Available options include: + +ID +TITLE +An ID number (up to 8 digits) may be defined for this switch command in the first 10- +character space. A title for the card may be input between the 11th and 80th character on +the title-ID line. The optional title line precedes all other cards for this command. +The user can explicitly define a title for this coupling. +Title Card. Additional card for the Title or ID keyword options. +Title +Variable +1 +ID +Type +I10 +2 +3 +4 +5 +6 +7 +8 +TITLE +A70 + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SID +STYPE +NQUAD +XOFF +BTIME +DTIME +NFREQ +NFOLD +Type +I +Default +none +I +0 +I +1 +F +F +F +0.0 +0.0 +1.0E20 +I +1 +I +Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FR_MMG TO_MMG +XLEN +Type +I +I +F +Default +none +none +0.0 + VARIABLE +SID +DESCRIPTION +A set ID defining a monitoring surface over which an ALE fluid +flows across, and its ALE multi-material-group-ID (AMMGID) is +switched. The monitoring surface may be a Lagrangian shell +structure, or a segment set. This surface, if Lagrangian, does not +have to be included in the coupling definition . +STYPE +Set ID type of the above SID. +EQ.0: Part set ID (PSID) (default). +EQ.1: Part ID (PID). +EQ.2: Segment set ID (SGSID). +NQUAD +XOFF +The number of flow-sensor points to be distributed over each +monitoring surface/segment. There should be enough sensor +points distributed to monitor the flow in each ALE element +intersected by this monitoring surface (default = 1, see remark 3). +An offset distance away from the monitoring surface, beyond +which the AMMGID switching occurs. The direction of XOFF is +defined by the normal vector of the monitoring segment. This +offset distance, in general, should be at least 2 ALE element +widths away from, and beyond the monitoring +interface +(default = 0.0). +BTIME +Start time for the AMMGID switch to be activated (default = 0.0). +DTIME +Ending time for the AMMGID switch (default = 1.0E20). +NFREQ +Number of computational cycles between ALE switch check +(default = 1). +Flag for checking folding logic (default = 0, ⇒ off). If NFOLD = 1 +(⇒ on), then LS-DYNA will check if the monitoring segment is in +the fold, applicable to airbag. If the monitoring segment is still +located within a folded (shell) region, then no switching is +allowed yet until it has unfolded. +This is the AMMG-SID before the switch. The AMMG-SID +corresponds to the SID defined under the *SET_MULTI-MATERI- +AL_GROUP_LIST (SMMGL) card. This SID points to one or +more AMMGs. See Remark 1. +This is the AMMG-SID after the switch. The AMMG-SID +corresponds to the SID defined under the *SET_MULTI-MATERI- +AL_GROUP_LIST card. This SID points to one or more AMMGs. +See Remark 1. +This is an absolute distance for distributing the flow sensor points +over the ALE elements. To make sure that at least 1 sensor point, +defined on each Lagrangian segment, is present in each ALE +element to track the flow of an AMMG, XLEN may be estimated +as roughly half the length of the smallest ALE element in the +mesh. See Remark 3. +*ALE + VARIABLE +NFOLD +FR_MMG +TO_MMG +XLEN +Remarks: +1. There is a correspondence between the FR_MMG and TO_MMG. Consider an +example where: +a) The FR_MMG SID points to a SID = 12 (the SID of its SMMGL card is 12, +and this SID contains AMMG 1 and AMMG 2) +b) The TO_MMG points to a SID = 34 (the SID of the SMMGL card is 34, and +this SID contains AMMG 3 and AMMG 4) +Then, AMMG 1, if switched, will become AMMG 3, and AMMG 2, if switched, +will become AMMG 4. +2. The ID option must be activated if the parameter SWID is used in the *DATA- +BAS_FSI card. Then the accumulated mass of an AMMG that goes through a +tracking surface, and being switched, will be reported via the parameter +“mout” in the “dbfsi” ASCII output file (or equivalently the “POROSITY” pa- +rameter inside LS-PrePost ASCII plotting option). +3. When both NQUAD and XLEN are defined, whichever gives smaller sensor- +point interval distance will be used. XLEN may give better control as in the +case of a null shell acting as the monitoring surface. As this null shell is +stretched, NQUAD distribution of sensor-points may not be adequate, but +XLEN would be. +4. The monitoring surface does not have to be included in the slave set of the +coupling card. However, at least one coupling card must be present in the +model. The monitoring segment set can be made up of Lagrangian or ALE +nodes. +Example: +Consider a simple airbag model with 3 part IDs: +H25 (AMMG1) = Inflator gas injected into the airbag. +H24 (AMMG2) = Air outside the airbag (background mesh). +H26 (AMMG3) = Dummy AMMG of inflator gas after it passes through a vent hole. +S9 = A Lagrangian shell part representing a vent hole. +S1 = A Lagrangian shell part representing the top half of an airbag. +S2 = A Lagrangian shell part representing the bottom half of an airbag. +The inflator gas inside the airbag is distinguished from the inflator gas that has passed +through the monitoring surface (vent hole) to the outside of the airbag by assigning +different ALE multi-material group set ID to each. The dummy fluid part (H26) should +have the same material and EOS model IDs as the before-switched fluid (H25). +TO_MMG = 125 +⇒ AMMGID (before switch) = *SET_MULTI-MATERIAL_GROUP_LIST(125) = 1 +⇒ PART = PART(AMMGID1) = H25 +FR_MMG = 126 +⇒ AMMGID (before switch) = *SET_MULTI-MATERIAL_GROUP_LIST(126) = 3 +⇒ PART = PART(AMMGID3) = H26 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*ALE_MULTI-MATERIAL_GROUP + 25 1 + 24 1 + 26 1 +*DATABASE_FSI +$ TOUT [STYPE: 0=PSID ; 1=PID ; 2=SGSID] + 0.1000 +$ DBFSI_ID SID STYPE AMMGSWID LDCONVID + 1 1 1 + 2 2 1 + 3 9 1 90000 +*SET_MULTI-MATERIAL_GROUP_LIST + 125 + 1 +*SET_MULTI-MATERIAL_GROUP_LIST + 126 + 3 +*ALE_FSI_SWITCH_MMG_ID + 90000 +$ SID SIDTYPE NQUAD XOFF BTIME DTIME NFREQ FOLD + 9 1 3 -20.0 5.0 0.0 1 1 +$ Fr_MMG To_MMG XCLEN + 125 126 5. +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +Note: +1. The *DATABASE_FSI card tracks 3 surface entities: (a) top half of an airbag, (b) +bottom half of an airbag, and (c) the vent hole monitoring surface where the +AMMGID of the inflator gas is switched. +2. The amount of mass passing through the vent hole during the switch is output +to a parameter called “pleak” in a “dbfsi” ASCII file. See *DATABASE_FSI. +3. The *ALE_FSI_SWITCH_MMG_ID card track any flow across S9 and switch the +AMMGSID from 125 (AMMG 1) to 126 (AMMG 3). +*ALE +Purpose: Output the ALE coupling forces from *CONSTRAINED_LAGRANGE_IN_- +SOLID, CTYPE = 4 in keyword format, so they may be applied directly in another run. + Card 1 +Variable +1 +DT +2 +3 +4 +5 +6 +7 +8 +NSID +IOPT +Type +I +I +Default +none +none +I +0 + VARIABLE +DESCRIPTION +DT +NSID +IOPT +Output intervals +Node Set ID. See *SET_NODE. +Options to map the coupling data between 2 runs: +EQ.0: The keyword alefsiloadnode.k is created +at the end of the run by LS-DYNA. +EQ.1: A database of coupling forces is dumped without the +conversion in keyword file at the end of the run . The database can be treated by a program +(alefsiloadnode.exe) to write alefsiloadnode.k. +EQ.2: The database of coupling forces created by IOPT = 1 is read back. The structure meshes should be +identical. The forces are directly applied the nodes with- +out using *LOAD_NODE. The parameters DT and NSID +are not read. +EQ.3: A database of coupling accelerations is dumped at the +end of the run . +EQ.4: The database of coupling accelerations created by +IOPT = 3 is read back. The structure +meshes can be different. The accelerations are interpo- +lated at the nodes provided by NSID. The parameters +DT and NSID are read. +*ALE_FSI_TO_LOAD_NODE +1. The name of the output keyword file is alefsiloadnode.k. For each node, this +file contains three *LOAD_NODE for each global direction and three *DE- +FINE_CURVE for the coupling force histories. +2. The name of the database is alefsi2ldnd.tmp (or alefsi2ldnd.tmp00… in MPP). +It should be in the directory of the 2nd run for IOPT = 2. The database lists the +coupling forces by node. The structure meshes (and their MPP decomposition) +for the IOPT = 1 and IOPT = 2 runs should be the same. +3. The names of the databases are alefsi2ldnd.tmp (or alefsi2ldnd.tmp00… in +MPP) and alefsi2lndndx.tmp. They should be in the directory of the 2nd run for +IOPT = 4. The file alefsi2ldnd.tmp lists the coupling accelerations by node +file +(coupling acceleration = coupling +alefsi2lndndx.tmp lists the initial nodal coordinates and coupling segment +connectivities . The structure meshes for the IOPT = 3 and IOPT = 4 runs can be +different. The IOPT = 3 initial geometry stored in alefsi2lndndx.tmp is used to +interpolate the coupling accelerations (saved in alefsi2ldnd.tmp) at the nodes +provided by NSID. For the interpolation to work, these nodes should be within +the IOPT = 3 coupling segment initial locations. +force / nodal mass). + The +*ALE_MULTI-MATERIAL_GROUP +*ALE_MULTI-MATERIAL_GROUP +*ALE +Purpose: This command defines the appropriate ALE material groupings for interface +reconstruction when two or more ALE Multi-Material Groups (AMMG) are present in a +model. This card is required when ELFORM = 11 in the *SECTION_SOLID card or +when ALEFORM = 11 in *SECTION_ALE1D or *SECTION_ALE2D. Each data line +represents one ALE multi-material group (AMMG), with the first line referring to AM- +MGID 1, second line AMMGID 2, etc. Each AMMG represents one unique “fluid” +which may undergo interaction with any Lagrangian structure in the model. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SID +IDTYPE +Type +I +Default +none +I +0 +Remarks +1 + VARIABLE +DESCRIPTION +SID +Set ID. +IDTYPE +Set type: +EQ.0: Part set, +EQ.1: Part. +Remarks: +1. When ELFORM = 12 in the *SECTION_SOLID card (single material and void), +this card should not be used. In one model, ELFORM = 12 cannot be used to- +gether with ELFORM = 11. If possible, it is recommended that ELFORM = 11 +be used as it is the most robust and versatile formulation for treating multi- +material ALE parts. +2. Each AMMG is automatically assigned an ID (AMMGID), and consists of one +or more PART ID’s. The interface of each AMMGID is reconstructed as it +evolves dynamically. Each AMMGID is represented by one material contour +color in LS-PrePost. +Physical +Material 3 +(PID 44) +Physical +Material 3 +(PID 55) +Physical +Material 3 +(PID 66) +Physical +Material 4 +(PID 77) +Physical +Material 1 +(PID 11) +Physical +Material 2 +(PID 22) +Physical +Material 2 +(PID 33) +Figure 4-1. Schematic illustration of Example 1. +3. The maximum number of AMMGIDs allowed has been increased to 20. +However, there may be 2, at most 3, AMMGs inside an ALE element at any- +time. If there are more than 3 AMMGs inside any 1 ALE element, the ALE +mesh needs refinement. Better accuracy is obtained with 2 AMMGs in mixed +elements. +4. To plot these AMMGIDs in LS-PrePost: +[FCOMP] ⇒ [MISC] ⇒ [VOLUME FRACTION OF AMMGID #] ⇒ [APPLY] +(Note: Contour definitions maybe different for gas mixture application) +5. +It is very important to distinguish among the +a) Physical materials, +b) PART IDs, and +c) AMMGIDs. +A *PART may be any mesh component. In ALE formulation, it is simply a +geometric entity and a time = 0 concept. This means a *PART may be a mesh +region that can be filled with one or more AMMGIDs at time zero, via a volume +filling command (*INITIAL_VOLUME_FRACTION_GEOMETRY). An AM- +MGID represents a physical material group which is treated as one material +entity (represented by 1 material color contour in LS-PrePost plotting). +AMMGID is used in dealing with multiple ALE or Eulerian materials. For +example, it can be used to specify a master ALE group in a coupling card. +Example 1: +Consider a purely Eulerian model containing 3 containers containing 2 different +physical materials (fluids 1 and 2). All surrounded by the background material (maybe +air). The containers are made of the same material, say, metal. Assume that these +containers explode and spill the fluids. We want to track the flow and possibly mixing +of the various materials. Note that all 7 parts have ELFORM = 11 in their *SECTION_- +SOLID cards. So we have total of 7 PIDs, but only 4 different physical materials. See +Figure 4-1. +Approach 1: If we want to track only the interfaces of the physical materials. +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*SET_PART + 1 + 11 +*SET_PART + 2 + 22 33 +*SET_PART + 3 + 44 55 66 +*SET_PART + 4 + 77 +*ALE_MULTI-MATERIAL_GROUP + 1 0 ← 1st line = 1st AMMG ⇒AMMGID = 1 + 2 0 ← 2nd line = 2nd AMMG ⇒AMMGID = 2 + 3 0 ← 3rd line = 3rd AMMG ⇒AMMGID = 3 + 4 0 ← 4th line = 4th AMMG ⇒AMMGID = 4 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +With this approach, we define only 4 AMMGs (NALEGP = 4). So in LS-PrePost, when +plotting the material-group (history variable) contours, we will see 4 colors, one for +each material group. One implication is that when the fluids from part 22 and part 33 +flow into the same element, they will coalesce and no boundary distinction between +them is maintained subsequently. While this may be acceptable for fluids at similar +thermodynamic states, this may not be intuitive for solids. For example, if the solid +container materials from parts 44, 55 and 66 flow into one element, they will coalesce +“like a single fluid”, and no interfaces among them are tracked. If this is undesirable, +an alternate approach may be taken. It is presented next. +Approach 2: If we want to reconstruct as many interfaces as necessary, in this case, we +follow the interface of each part. +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*ALE_MULTI-MATERIAL_GROUP + 1 1 ← 1st line = 1st AMMG ⇒AMMGID = 1 + 2 1 ← 2nd line = 2nd AMMG ⇒AMMGID = 2 + 3 1 ← 3rd line = 3rd AMMG ⇒AMMGID = 3 + 4 1 ← 4th line = 4th AMMG ⇒AMMGID = 4 + 5 1 ← 4th line = 5th AMMG ⇒AMMGID = 5 + 6 1 ← 4th line = 6th AMMG ⇒AMMGID = 6 + 7 1 ← 4th line = 7th AMMG ⇒AMMGID = 7 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +There are 7 AMMGs in this case (NALEGP = 7). This will involve more computational +cost for the additional tracking. Realistically, accuracy will be significantly reduced if +there are more than 3 or 4 materials in any one element. In that case, higher mesh +resolution may be required. +Example 2: +Oil +Water +Air +Group 1 +Group 2 +Group 3 +Part IDs 1 and 2 +Part ID 3 +Part IDs 5, 6, and 7 +The above example defines a mixture of three groups of materials (or “fluids”), oil, +water and air, that is, the number of ALE multi-material groups (AMMGs) +NALEGP = 3. +The first group contains two parts (materials), part ID's 1 and 2. +The second group contains one part (material), part ID 3. +The third group contains three parts (materials), part ID's 5, 6 and 7. +*ALE +Purpose: This command defines a motion and/or a deformation prescribed for a +geometric entity, where a geometric entity may be any part, part set, node set, or +segment set. The motion or deformation is completely defined by the 12 parameters +shown in the equation below. These 12 parameters are defined in terms of 12 load +curves. This command is required only when PRTYPE = 3 in the *ALE_REFERENCE_- +SYSTEM_GROUP command. +2 +3 +4 +5 +6 +7 +8 + Card 1 +Variable +1 +ID +Type +I +Default +none + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCID1 +LCID2 +LCID3 +LCID4 +LCID5 +LCID6 +LCID7 +LCID8 +Type +I +I +I +I +I +I +I +I +Default +none +none +none +none +none +none +none +none + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCID9 +LCID10 +LCID11 +LCID12 +Type +I +I +I +I +Default +none +none +none +none + VARIABLE +DESCRIPTION +ID +Curve group ID. +LCID1, …, LCID12 +Load curve IDs. +*ALE_REFERENCE_SYSTEM_CURVE +1. The velocity of a node at coordinate (𝑥, 𝑦, 𝑧) is defined as: +{⎧𝑥̇ +}⎫ +𝑦̇ +𝑧̇⎭}⎬ +⎩{⎨ += +{⎧𝑓1 +}⎫ +𝑓5 +𝑓9⎭}⎬ +⎩{⎨ ++ +𝑓2 +⎡ +𝑓6 +⎢ +𝑓10 +⎣ +𝑓3 +𝑓7 +𝑓11 +𝑓4 +⎤ +𝑓8 +⎥ +𝑓12⎦ +{⎧𝑥 − XC +}⎫ +𝑦 − YC +𝑧 − ZC⎭}⎬ +⎩{⎨ +where 𝑓1(𝑡) is the value of load curve LCID1 at time 𝑡, 𝑓2(𝑡) is the value of load +curve LCID2 at time 𝑡 and so on. The functions 𝑓1(𝑡), 𝑓5(𝑡), and 𝑓9(𝑡) respectively +correspond to the translation components in global 𝑥, 𝑦, and 𝑧 direction, while +the functions 𝑓2(𝑡), 𝑓7(𝑡), and 𝑓12(𝑡) correspond to and expansion or contraction +along the 𝑥, 𝑦, and 𝑧 axes. +The parameters XC, YC and ZC from the second data card of *ALE_REFER- +ENCE_SYSTEM_GROUP define the center of rotation and expansion of the +mesh. If the mesh translates, the center position is updated with 𝑓1(𝑡), 𝑓5(𝑡), +and 𝑓9(𝑡). +If LCID8, LCID10, LCID3 are equal to −1, their corresponding values 𝑓8(𝑡), +𝑓10(𝑡), and 𝑓3(𝑡) will be equal to −𝑓11(𝑡), −𝑓4(𝑡), and −𝑓6(𝑡) so as to make a skew +symmetric matrix thereby inducing a rigid rotation of the mesh about the axis 𝐯 +defined by the triple, +𝐯 = (𝑓11(𝑡), 𝑓4(𝑡), 𝑓6(𝑡)) +Example: +Consider a motion that consists of translation in the x and y direction only. Thus +only 𝑓1(𝑡) and 𝑓5(𝑡) are required. Hence only 2 load curve ID’s need be defined: +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|...8 +*ALE_REFERENCE_SYSTEM_GROUP +$ SID STYPE PRTYP PRID BCTRAN BCEXP BCROT ICOORD + 1 0 3 11 0 7 0 +$ XC YC ZC EXPLIM + 0 0 0 0 +*ALE_REFERENCE_SYSTEM_CURVE +$ CURVESID + 11 +$ LCID1 LCID2 LCID3 LCID4 LCID5 LCID6 LCID7 LCID8 + 111 0 0 0 222 0 0 0 +$ LCID9 LCID10 LCID11 LCID12 + 0 0 0 0 +*DEFINE_CURVE +$ lcid sidr sfa sfo offa offo dattyp + 111 +$ a1 o1 + 0.00 5.0 + 0.15 4.0 +*DEFINE_CURVE +$ lcid sidr sfa sfo offa offo dattyp + 222 +$ a1 o1 + 0.00 -1.0 +0.15 -5.0 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*ALE_REFERENCE_SYSTEM_GROUP +Purpose: This card is used to associate a geometric entity to a reference system type. A +geometric entity may be any part, part set, node set, or segment set of a model (or a +collection of meshes). A reference system type refers to the possible transformation +allowed for a geometric entity (or mesh). This command defines the type of reference +system or transformation that a geometric entity undergoes. In other words, it +prescribes how certain mesh can translate, rotate, expand, contract, or be fixed in space, +etc. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SID +STYPE +PRTYPE +PRID +BCTRAN +BCEXP +BCROT +ICR/NID +Type +I +Default +none + Card 2 +Variable +1 +XC +Type +F +I +0 +2 +YC +F +I +0 +3 +ZC +F +I +0 +4 +I +0 +5 +I +0 +6 +I +0 +7 +I +0 +8 +EXPLIM +EFAC +FRCPAD +IEXPND +F +F +F +0.1 +I +0 +Default +0.0 +0.0 +0.0 +inf. +0.0 +Remaining cards are optional.† + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IPIDXCL +IPIDTYP +Type +Default +I +0 +I +VARIABLE +DESCRIPTION +SID +Set ID. +STYPE +Set type: +EQ.0: part set, +EQ.1: part, +EQ.2: node set, +EQ.3: segment set. +PRTYPE +Reference system type : +EQ.0: Eulerian, +EQ.1: Lagrangian, +EQ.2: Normal ALE mesh smoothing, +EQ.3: Prescribed motion following load curves, see *ALE_REF- +ERENCE_SYSTEM_CURVE, +EQ.4: Automatic mesh motion following mass weighted +average velocity in ALE mesh, +EQ.5: Automatic mesh motion following a local coordinate +system defined by three user defined nodes, see *ALE_- +REFERENCE_SYSTEM_NODE, +EQ.6: Switching in time between different reference system +types, see *ALE_REFERENCE_SYSTEM_SWITCH, +EQ.7: Automatic mesh expansion in order to enclose up to +twelve user defined nodes, see *ALE_REFERENCE_SYS- +TEM_NODE. +EQ.8: Mesh smoothing option for shock waves, where the +element grid contracts in the vicinity of the shock front: +this may be referred to as the Delayed-ALE option. It +controls how much the mesh is to be moved during the +remap step. This option requires the definition of the 5th +parameter in the 2nd card, EFAC; see below for defini- +tion. +EQ.9: Allowing the ALE mesh(es) to: +1. Translate and/or rotate to follow a local Lagrangian +reference coordinate system +*ALE_REFER- +ENCE_SYSTEM_NODE card ID is defined by the BC- +TRAN parameter) +(whose +VARIABLE +DESCRIPTION +2. Expand or contract to enclose a Lagrangian part-set ID +defined by the PRID parameter. +3. Has a Lagrangian node ID be defined by the ICR/NID +parameter to be the center of the ALE mesh expansion. +PRID +A parameter giving additional information depending on the +reference system (PRTYPE) choice: +PRTYPE.EQ.3: PRID defines a load curve group ID specifying +an *ALE_REFERENCE_SYSTEM_CURVE card +for mesh translation. This defines up to 12 +curves which prescribe the motion of the sys- +tem. +PRTYPE.EQ.4: PRID defines a node set ID (*SET_NODE), for +which a mass average velocity is computed. +This velocity controls the mesh motion. +PRTYPE.EQ.5: PRID defines a node group ID specifying an +*ALE_REFERENCE_SYSTEM_NODE card, via +which, three nodes forming a local coordinate +system are defined. +PRTYPE.EQ.6: PRID defines a switch list ID specifying an +*ALE_REFERENCE_SYSTEM_SWITCH +card. +This defines the switch times and the reference +system choices for each time interval between +the switches. +PRTYPE.EQ.7: PRID defines a node group ID specifying an +*ALE_REFERENCE_SYSTEM_NODE card. Up +to 12 nodes in space forming a region to be en- +veloped by the ALE mesh are defined. +PRTYPE.EQ.9: PRID defines a Lagrangian part set ID (PSID) +defining the Lagrangian part(s) whose range of +motion is to be enveloped by the ALE mesh(es). +This is useful for airbag modeling. +If PRTYPE.EQ.4 or PRTYPE.EQ.5, then +BCTRAN +BCTRAN is a translational constraint (Remark 3). +EQ.0: no constraints, +EQ.1: constrained 𝑥 translation, +VARIABLE +DESCRIPTION +EQ.2: constrained 𝑦 translation, +EQ.3: constrained 𝑧 translation, +EQ.4: constrained 𝑥 and 𝑦 translation, +EQ.5: constrained 𝑦 and 𝑧 translation, +EQ.6: constrained 𝑧 and 𝑥 translation, +EQ.7: constrained 𝑥, 𝑦, and 𝑧 translation. +Else If PRTYPE.EQ.9, then +BCTRAN +BCTRAN is a node group ID from a *ALE_REFERENCE_SYS- +TEM_NODE card prescribing a local coordinate system (3 node +IDs) whose motion is to be followed by the ALE mesh(es). +Else +BCTRAN +Ignored +End if +BCEXP +For PRTYPE = 4 & 7 BCTRAN is an expansion constraint, +otherwise it is ignored (Remark 3). +EQ.0: no constraints, +EQ.1: constrained 𝑥 expansion, +EQ.2: constrained 𝑦 expansion, +EQ.3: constrained 𝑧 expansion, +EQ.4: constrained 𝑥 and 𝑦 expansion, +EQ.5: constrained 𝑦 and 𝑧 expansion, +EQ.6: constrained 𝑧 and 𝑥 expansion, +EQ.7: constrained 𝑥, 𝑦, and 𝑧 expansion. +BCROT +BCROT is a rotational constraint (Remark 3). Otherwise, BCROT +is ignored. +EQ.0: no constraints, +EQ.1: constrained 𝑥 rotation, +EQ.2: constrained 𝑦 rotation, +VARIABLE +DESCRIPTION +EQ.3: constrained 𝑧 rotation, +EQ.4: constrained 𝑥 and 𝑦 rotation, +EQ.5: constrained 𝑦 and 𝑧 rotation, +EQ.6: constrained 𝑧 and 𝑥 rotation, +EQ.7: constrained 𝑥, 𝑦, and 𝑧 rotation. +If PRTYPE.EQ.4 +ICR/(NID) +ICR is a flag the specifies the method LS-DYNA uses for +determining +the center point for expansion and rotation +(Remark 3). +EQ.0: The center is at center of gravity of the ALE mesh. +EQ.1: The center is at (XC, YC, ZC), just a point in space (it +does not have to be a defined node) +Else if PRTYPE.EQ.9 +(ICR)/NID +NID sets the Lagrangian node ID for the node that anchors the +center of ALE mesh expansion (Remark 2). +End if +XC, YC, ZC +EXPLIM +Center of mesh expansion and rotation for PRTYPE = 4 and 5, +otherwise ignored. See ICR above. +Limit ratio for mesh expansion and contraction. Each Cartesian +direction is treated separately. The distance between the nodes is +not allowed to increase by more than a factor EXPLIM, or +decrease to less than a factor 1/EXPLIM. This flag applies only +for PRTYPE = 4, otherwise it is ignored. +EFAC +Mesh remapping factor for PRTYPE = 8 only, otherwise it is +ignored. EFAC is allowed to range between 0.0 and 1.0. When +EFAC approaches 1.0, the remapping approaches the Eulerian +behavior. +The smaller the value of EFAC, the closer the mesh will follow the +material flow in the vicinity of a shock front, i.e. approaching +Lagrangian behavior. +Note that excessively small values for EFAC can result in severe +VARIABLE +DESCRIPTION +FRCPAD +mesh distortions as the mesh follows the material flow. As time +evolves, the mesh smoothing behavior will approach that of an +Eulerian system. +For PRTYPE = 9 this is an ALE mesh padding fraction, otherwise +it is ignored. +FRCPAD is allowed to range from 0.01 to 0.2. If the characteristic +Lagrange mesh dimension, 𝑑𝐿1, exceeds +(1 − 2 × FRCPAD) × 𝑑𝐿𝐴, +where 𝑑𝐿𝐴 is the characteristic length of the ALE mesh, then the +ALE mesh is expanded so that +𝑑𝐿𝐴 = +𝑑𝐿1 +1 − 2 × FRCPAD +. +This provides an extra few layers of ALE elements beyond the +maximum Lagrangian range of motion. +EQ.0.01: 𝑑𝐿𝐴 = +EQ.0.20: 𝑑𝐿𝐴 = +𝑑𝐿𝐿 +⁄ +0.98 +𝑑𝐿𝐿 +⁄ +0.60 += 𝑑𝐿𝐿 × 1.020408 += 𝑑𝐿𝐿 × 1.666667 +IEXPND +For PRTYPE = 9 this is an ALE mesh expansion control flag, +otherwise it is ignored. +EQ.0: Both mesh expansion and contraction are allowed. +EQ.1: Only mesh expansion is allowed: +IPIDXCL +An ALE set ID to be excluded from the expansion and/or +contraction only. Translation and rotation are allowed. For +example, this may be used to prevent the ALE mesh (or part) at +the inflator gas inlet region from expanding too much. High ALE +mesh resolution is usually required to resolve the high speed flow +of the gas into the airbag via point sources . +IPIDTYPE +Set ID type of IPIDXCL: +EQ.0: PSID +EQ.1: PID +*ALE_REFERENCE_SYSTEM_GROUP +1. Required Associated Cards. Some PRTYP values may require a supple- +mental definition defined via corresponding PRID. For example, PRTYP = 3 +requires a *ALE_REFERENCE_SYSTEM_CURVE card. If PRID = n, then in the +corresponding *ALE_REFERENCE_SYSTEM_CURVE card, ID = n. Similar +association applies for any PRTYP (i.e. 3, 5, 6, or 7) which requires a definition +for its corresponding PRID parameter. +2. Mesh Centering. For PRTYPE = 9: ICR/NID can be useful to keep a high +density ALE mesh centered on the region of greatest interest, (such as the in- +flator orifices region in an airbag model). For example, in the case of nonsym- +metrical airbag deployment, assuming that the ALE mesh is initially finer near +the inlet orifices, and gradually coarsened away from it. Defining an “anchor +node” at the center of the orifice location will keep the fine ALE mesh region +centered on the orifice region. So that this fine ALE mesh region will not be +shifted away (from the point sources) during expansion and translation. The +ALE mesh can move and expand outward to envelop the Lagrangian airbag in +such a way that the inlet is well resolved throughout the deployment. +3. Additional Constraints. The table below shows the applicability of the various +choices of PRTYPE. Simple deductions from the functional definitions of the +PRTYPE choices will clarify the applications of the various constraints. For +example, when PRTYP = 3, nodal motion of the ALE mesh is completely con- +trolled by the 12 curves. Therefore, no constraints are needed. +PRTYPE +ICR/NID +BCTRAN +BCROT +BCEXP +3 +4 +5 +6 +7 +8 +9 +NO +YES (ICR) +NO +NO +NO +NO +NO +YES +YES +NO +NO +NO +YES (NID) +YES (NGID) +NO +YES +NO +NO +NO +NO +NO +NO +YES +NO +NO +YES +NO +NO +Example 1: +Consider a bird-strike model containing 2 ALE parts: a bird is surrounded by air (or +void). A part-set ID 1 is defined containing both parts. To allow for the meshes of these +2 parts to move with their combined mass-weighted-average velocity, PRTYPE = 4 is +used. Note that BCEXP = 7 indicating mesh expansion is constrained in all global +directions. +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|...8 +*ALE_REFERENCE_SYSTEM_GROUP +$ SID STYPE PRTYP PRID BCTRAN BCEXP BCROT ICOORD + 1 0 4 0 0 7 0 +$ XC YC ZC EXPLIM + 0 0 0 0 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|...8 +Example 2: +Consider a bouncing ball model containing 2 ALE parts: a solid ball (PID 1) is +surrounded by air or void (PID 2). A part-set ID 1 is defined containing both parts. To +allow for the meshes of these 2 parts to move with 2 reference system types: (a) first, +they move with their combined mass-weighted-average velocity between 0.0 and 0.01 +second; and subsequently (between 0.01 and 10.0 seconds) their reference system is +switched to (b) an Eulerian system (thus the mesh is fixed in space), a reference system +“SWITCH” is required. This is done by setting PRTYPE = 6. This PRTYPE requires a +corresponding *ALE_REFERENCE_SYSTEM_SWITCH card. Note that PRID = 11 in the +*ALE_REFERENCE_SYSTEM_GROUP card corresponds to the SWITCHID = 11 in +*ALE_REFERENCE_SYSTEM_SWITCH card. +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*ALE_REFERENCE_SYSTEM_GROUP +$ SID STYPE PRTYP PRID BCTRAN BCEXP BCROT ICOORD + 1 0 6 11 0 7 7 +$ XC YC ZC EXPLIM EULFACT SMOOTHVMX + 0 0 0 0 0.0 +*ALE_REFERENCE_SYSTEM_SWITCH +$ SWITCHID + 11 +$ t1 t2 t3 t4 t5 t6 t7 + 0.01 10.0 +$ TYPE1 TYPE2 TYPE3 TYPE4 TYPE5 TYPE6 TYPE7 TYPE8 + 4 0 +$ ID1 ID2 ID3 ID4 ID5 ID6 ID7 ID8 + 0 0 0 0 0 0 0 0 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*ALE_REFERENCE_SYSTEM_NODE +Purpose: This command defines a group of nodes that control the motion of an ALE +mesh. It is used only when PRTYPE = 5 or 7 in a corresponding *ALE_REFERENCE_- +SYSTEM_GROUP card. +2 +3 +4 +5 +6 +7 +8 + Card 1 +Variable +1 +ID +Type +I +Default +none + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NID1 +NID2 +NID3 +NID4 +NID5 +NID6 +NID7 +NID8 +Type +I +I +I +I +I +I +I +I +Default +none +none +none +none +none +none +none +none + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NID9 +NID10 +NID11 +NID12 +Type +I +I +I +I +Default +none +none +none +none + VARIABLE +DESCRIPTION +ID +Node group ID for PRTYPE 5 or 7, see *ALE_REFERENCE_SYS- +TEM_GROUP. +User specified nodes. +NID1, …, +NID12 +Remarks: +1. For PRTYPE = 5 the ALE mesh is forced to follow the motion of a coordinate +system, which is defined by three nodes (NID1, NID2, NID3). These nodes are +located at 𝑥1, 𝑥2 and 𝑥3, respectively. The axes of the coordinate system, 𝑥′, 𝑦′, +and 𝑧′, are defined as: +𝑥′ = +𝑥2 − 𝑥1 +|𝑥2 − 𝑥1| +𝑦′ = 𝑧′ × 𝑥′ + 𝑧′ = 𝑥′ × +𝑥3 − 𝑥1 +∣𝑥′ × (𝑥3 − 𝑥1)∣ +Note that 𝑥1 → 𝑥2 is the local 𝑥′axis, 𝑥1 → 𝑥3 is the local 𝑦′ axis and 𝑥′ crosses 𝑦′ +gives the local 𝑧′ axis. These 3 nodes are used to locate the reference system at +any time. Therefore, their positions relative to each other should be as close to +an orthogonal system as possible for better transformation accuracy of the ALE +mesh. +2. For PRTYPE = 7, the ALE mesh is forced to move and expand, so as to enclose +up to twelve user defined nodes (NID1, …, NID12). This is a rarely used op- +tion. +Example 1: +Consider modeling sloshing of water inside a rigid tank. Assuming there are 2 ALE +parts, the water (PID 1) and air or void (PID 2) contained inside a rigid (Lagrangian) +tank (PID 3). The outer boundary nodes of both ALE parts are merged with the inner +tank nodes. A part-set ID 1 is defined containing both ALE parts (PIDs 1 and 2). To +allow for the meshes of the 2 ALE parts to move with the rigid Lagrangian tank, +PRTYPE = 5 is used. The motion of the ALE parts then follows 3 reference nodes on the +rigid tank. These 3 reference nodes must be defined by a corresponding *ALE_REFER- +ENCE_SYSTEM_NODE card. In this case the reference nodes have the nodal IDs of 5, 6 +and 7. Note that PRID = 12 in the +*ALE_REFERENCE_SYSTEM_GROUP card corresponds to the SID = 12 in the *ALE_- +REFERENCE_SYSTEM_NODE card. +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|...8 +*ALE_REFERENCE_SYSTEM_GROUP +$ SID STYPE PRTYP PRID BCTRAN BCEXP BCROT ICOORD + 1 0 5 12 +$ XC YC ZC EXPLIM + 0 0 0 0 +*ALE_REFERENCE_SYSTEM_NODE +$ NSID + 12 +$ N1 N2 N3 N4 N5 N6 N7 N8 + 5 6 7 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|...8 +*ALE_REFERENCE_SYSTEM_SWITCH +Purpose: The PRTYPE parameter in the *ALE_REFERENCE_SYSTEM_GROUP (ARSG) +card allows many choices of the reference system types for any ALE geometric entity. +This command allows for the time-dependent switches between these different types of +reference systems, i.e., switching to multiple PRTYPEs at different times during the +simulation. This command is required only when PRTYPE = 6 in ARSG card. Please +see example 2 in the ARSG section. +2 +3 +4 +5 +6 +7 +8 + Card 1 +Variable +1 +ID +Type +I +Default +none + Card 2 +Variable +1 +T1 +Type +F +2 +T2 +F +3 +T3 +F +4 +T4 +F +5 +T5 +F +6 +T6 +F +7 +T7 +F +8 +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TYPE1 +TYPE2 +TYPE3 +TYPE4 +TYPE5 +TYPE6 +TYPE7 +TYPE8 +Type +Default +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +I +Card 4 +1 +Variable +ID1 +2 +ID2 +3 +ID3 +4 +ID4 +5 +ID5 +6 +ID6 +7 +ID7 +8 +ID8 +Type +I +I +I +I +I +I +I +I +Default +none +none +none +none +none +none +none +none + VARIABLE +DESCRIPTION +ID +Switch list ID, see *ALE_REFERENCE_SYSTEM_GROUP, +T1, …, T7 +TYPE1, …, +TYPE8 +Times for switching reference system type. By default, the +reference system TYPE1 occurs between time = 0 and time = T1, +and TYPE2 occurs between time = T1 and time = T2, etc. +Reference system types (also see PRTYPE under ARSG): +EQ.0: Eulerian, +EQ.1: Lagrangian, +EQ.2: Normal ALE mesh smoothing, +EQ.3: Prescribed motion following load curves, see *ALE_REF- +ERENCE_SYSTEM_CURVE, +EQ.4: Automatic mesh motion following mass weighted +average velocity in ALE mesh, +EQ.5: Automatic mesh motion following a local coordinate +system defined by three user defined nodes, see *ALE_- +REFERENCE_SYSEM_NODE, +ID1, …, ID8 +The corresponding PRID parameters supporting each PRTYPE +used during the simulation. +Remarks: +1. The beginning time is assumed to be t = 0, and the starting PRTYPE is TYPE1. +So at T1, the 1st switching time, PRTYPE is switched from TYPE1 to TYPE2, and +so forth. This option can be complex in nature so it is seldom applied. +See *CONTROL_REFINE_ALE. +*ALE +*ALE_SMOOTHING +Purpose: This smoothing constraint keeps an ALE slave node at its initial parametric +location along a line between two other ALE nodes. If these nodes are not ALE nodes, +the slave node has to follow their motion . This constraint is active +during each mesh smoothing operation. This keyword can be used with ALE solids, +ALE shells and ALE beams. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SNID +MNID1 +MNID2 +IPRE +XCO +YCO +ZCO +Type +I +I +I +Default +none +none +none +I +0 +F +F +F +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +SNID +Slave ID, see Figure 4-2. +GT.0: SNID is an ALE node, +EQ.0: the slaves are the nodes of an ALE mesh connected to the +first master nodes (MNID1). See Remarks 2 and 4. +LT.0: |SNID| is a ID of ALE node set. See Remark 2. +1st master node +slave node +Figure 4-2. This simple constraint, which ensures that a slave node remains +on a straight line between two master nodes, is sometimes necessary during +ALE smoothing. +2nd master node +VARIABLE +DESCRIPTION +MNID1 +First master ID. +GT.0: MNID1 is a node, +LT.0: |MNID1| +is +if +XCO = YCO = ZCO = 0.0. Otherwise, |MNID1| is a +node set ID. See Remarks 2 and 3. +segment +set +ID +a +MNID2 +Second master ID. +GT.0: MNID2 is a node, +EQ.0: the slave motion is solely controlled by MNID1. See +Remark 5. +LT.0: |MNID2| is a node set ID. See Remark 2. +IPRE +EQ.0: smoothing constraints are performed after mesh +relaxation, +EQ.1: smoothing constraints are performed before mesh +relaxation. +𝑥-coordinate of constraint vector +𝑦-coordinate of constraint vector +𝑧-coordinate of constraint vector +XCO +YCO +ZCO +Remarks: +1. When Master Nodes Are Not ALE Nodes. If SNID, MNID1 and MNID2 are +ALE nodes, the positions of MNID1 and MNID2 are interpolated to position +SNID. If MNID1 and MNID2 are not ALE nodes, the motions of MNID1 and +MNID2 are interpolated to move SNID. +2. Node Sets for Constraint Generation. If MNID1 is a set, SNID and MNID2 +should be node sets or zeros. In such a case, the constraints are created during +the initialization and printed out in a file called alesmoothingenerated.k for the +user’s convenience. +3. Constraint Generation Algorithm. The constraints for a given master node in +MNID1 are generated by finding the closest slave nodes to an axis passing +through +the constraint vector +(XCO,YCO,ZCO) if MNID1 is a node set. If MNID1 is a segment set, the nor- +the master node and oriented by +mals of the segments connected to the master node are averaged to give a direc- +tion to the axis. +4. Automatic Identification of Slave Nodes. If SNID=0, MNID1 should be a set +of nodes or segments along the boundary of an ALE mesh. For a given master +node in MNID1, the constraints are created for all the nodes of the mesh found +the closest to the axis described previously. The search of slaves starts with +nodes of elements connected to the master node and stops when a boundary +node with an element connectivity similar to the master node’s one is reached +or when a node in the set MNID2 (if defined) is found. +5. MNID2 = 0. If MNID2=0 and SNID is defined, MNID1 should not be ALE. +Otherwise SNID and MNID1 positions would match and the element volumes +between them could be zero or negative. Only SNID and MNID1 motion +should match in such a case. +*ALE +Purpose: This keyword generates a structured 3D mesh and invokes the Structured +ALE (S-ALE) solver. Spacing parameters are input through one or more of the *ALE_- +STRUCTURED_MESH_CONTROL_POINTS cards. The local coordinate system is +defined using the *ALE_STRUCTURED_MESH card. +In certain contexts it is advantageous to use structured meshes. With structured meshes +the element and node connectivity are straightforward and the searching algorithm +used for ALE coupling is greatly simplified. Also numerous checks are avoided +because these meshes include only HEX elements. +This new S-ALE solver supports SMP, MPP and MPP hybrid configurations. All three +implementations require less simulation time and memory usage than the regular ALE +solver. We, therefore, encourage using the S-ALE solver when the ALE mesh is +structured. +The S-ALE solver uses the same set of keyword cards as the regular ALE solver with the +only exception being this keyword. Once an ALE mesh is generated using *ALE_- +STRUCTURED_MESH card this card invokes the S-ALE and performs the ALE +advection timestep. For fluid structured interaction using the *CONSTRAINED_- +LARGANGE_IN_SOLID card S-ALE uses a much faster searching algorithm that takes +advantage of the mesh structure. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MSHID +DPID +NBID +EBID +Type +Default +I +0 +I +none + Card 2 +1 +2 +I +0 +3 +I +0 +4 +5 +6 +7 +8 +Variable +CPIDX +CPIDY +CPIDZ +NID0 +LCSID +Type +I +I +I +I +I +Default +none +none +none +none +none +VARIABLE +DESCRIPTION +MSHID +DPID +NBID +EBID +CPIDX, CPIDY, CPIDZ +S-ALE Mesh ID. A unique number must be specified. +Default Part ID. The elements generated will assigned +to DPID. This part contains no material including only +the mesh. +is automatically +generated during the input phase and contains neither +material nor element formulation information. Please +see Remark 1. + This part definition +Nodes are generated and assigned with node IDs +starting from NBID. +Elements are generated and assigned with element IDs +starting from EBID. +Control point IDs defining node ID/value pairs along +each local axis. See *ALE_STRUCTURED_MESH_- +CONTROL_POINTS. +NID0 + During the +NID0 sets the mesh’s origin node. +simulation, prescribed motion applied to this node +applies to the entire structure S-ALE mesh. +LCSID +Local coordinate system ID. Please see Remark 2. +Remarks: +1. DPID. The part specific by ID DPID wholey consists of elements and nodes. It +does not include material properties or integration rules. The requirmenet that +a part ID be specified for these automatically generated S-ALE solid elements +exusts only to satisfy the legacy rule that every element must be associated with +a part. Users do not need to set up the *PART card for DPID. All PART defini- +tions used in this card only refer to mesh, not material. +2. LCSID. The local coordinate system is defined on the data cards associated +with the *DEFINE_COORDINATE keyword. This local coordinate cordinate +system specifies the three cardinal directions used for generating the structured +ALE mesh. The structured mesh can be made to rotate by specifying a rotating +local coordinate system. To define a rotating local coordinate system, use the +*DEFINE_COORDINATE_NODES keyword with FLAG = 1 and then apply +prescribed motion to the three coordinate nodes. +3. ALES-ALE Converter. For existing ALE models with rectilinear mesh, we +could use *ALE_STRUCTURED_MESH card to invoke the ALE S-ALE con- +verter. To invoke this feature, add a *ALE_STRUCTURED_MESH card in the +model input with CPIDX=-1/0 and all other fields blank. It will then convert +all ALE keywords to be of S-ALE format and write the modified input in a file +named “saleconvrt.inc”. The solver used to perform the analysis depends on +the value of CPIDX. If -1, S-ALE solver is used; if 0, ALE solver is used. +Example: +The following example generates a regular evenly distributed 0.2 by 0.2 by 0.2 box mesh +having 22 nodes along each direction. The generated mesh is aligned to the local +coordinate system spefied by nodes 1, 2, 3, and 4 originating from node 1. +All the elements inside the mesh are assigned to part 1. Note that part 1 is not explicitly +defined in the input. The necessary part definition is automatically generated and +contains neither material definitions nor integration rules. +*ALE_STRUCTURED_MESH +$ mshid dpid nbid ebid + 1 1 200001 200001 +$ cpidx cpidy cpidz nid0 lcsid + 1001 1001 1001 1 234 +*DEFINE_COORDINATE_NODES +$ cid nid1 nid2 nid3 flag + 234 2 3 4 1 +*ALE_STRUCTURED_MESH_CONTROL_POINTS + 1001 +$ x1 x2 + 1 .0 + 22 .2 +*NODE + 1 0.0000000e+00 0.0000000e+00 0.0000000e+00 + 2 0.0000000e+00 0.0000000e+00 0.0000000e+00 + 3 0.1000000e+00 0.0000000e+00 0.0000000e+00 + 4 0.0000000e+00 0.1000000e+00 0.0000000e+00 +*END +*ALE_STRUCTURED_MESH_CONTROL_POINTS +Purpose: The purpose of this keyword is to provide spacing information used by the +*ALE_STRUCTURED_MESH keyword to generate a 3D structured ALE mesh. +Each instance of the *ALE_STRCUTURED_MESH_CONTROL_POINTS card defines a +one-dimensional mesh using control. Each control point consists of a node number and of a coordinate . The first control point must be node 1, and +the node number of the last point defines the total number of nodes. Between and two +control points the mesh is uniform. The *ALE_STRUCTURED_MESH card, in turn, +defines a simple three dimensional mesh from the triple product of three *ALE_STRUC- +TURED_MESH_CONTROL_POINT one-dimensional meshes. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CPID +Not used Not used +SFO +Not used +OFFO +Type +I +Default +None +F +1. +F +0. +Point Cards. Put one pair of points per card (2E20.0). Input is terminated at the next +keyword (“*”) card. At least two cards are required, one of which, having N = 1 is required. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +N +X +RATIO +Type +I20 +E20.0 +E20.0 +Default +none +none +0.0 + VARIABLE +DESCRIPTION +CPID +SFO +Control Points ID. A unique number must be specified. This ID +is to be referred in the three fields marked up CPIDX, CPIDY, +CPIDZ in *ALE_STRUCTURED_MESH. +Scale factor for ordinate value. This is useful for simple +modifications. +EQ.0.0: default set to 1.0. +VARIABLE +DESCRIPTION +OFFO +Offset for ordinate values. See Remark 1. +Control point node number. +Control point position. +Ratio for progressive mesh spacing. Progressively larger or +smaller mesh will be generated between the control point that has +nonzero ratio specified and the control point following it. See +remark 2. +GT.0.0: mesh size increases; 𝑑𝑙𝑛+1 = 𝑑𝑙𝑛 ∗ (1 + 𝑟𝑎𝑡𝑖𝑜) +LT.0.0: mesh size decreases; 𝑑𝑙𝑛+1 = 𝑑𝑙𝑛/(1 − 𝑟𝑎𝑡𝑖𝑜) +N +X +RATIO +Remarks: +1. Coordinates scaling. The ordinate values are scaled after the offsets are +applied, i.e.: +Ordinate value = SFO × (Defined value + OFFO) +2. Progressive mesh spacing. The formula used to calculate element length is +as follows: 𝑑𝑙𝑏𝑎𝑠𝑒 = ∣𝑥𝑒𝑛𝑑 − 𝑥𝑠𝑡𝑎𝑟𝑡∣ ∗ (𝑓𝑎𝑐𝑡𝑜𝑟 − 1)/(𝑓𝑎𝑐𝑡𝑜𝑟𝑛 − 1) in which 𝑑𝑙𝑏𝑎𝑠𝑒 is +the smallest base length; 𝑥𝑠𝑡𝑎𝑟𝑡 and 𝑥𝑒𝑛𝑑 are the coordinate of the start and end +point +𝑓𝑎𝑐𝑡𝑜𝑟 = 1 + 𝑟𝑎𝑡𝑖𝑜 (𝑟𝑎𝑡𝑖𝑜 > 0) 𝑜𝑟 1/(1 − 𝑟𝑎𝑡𝑖𝑜) (𝑟𝑎𝑡𝑖𝑜 < 0). +Please note here element size either increases by 𝑟𝑎𝑡𝑖𝑜 (𝑟𝑎𝑡𝑖𝑜 > 0) or decreases by +−𝑟𝑎𝑡𝑖𝑜/(1 − 𝑟𝑎𝑡𝑖𝑜) (𝑟𝑎𝑡𝑖𝑜 < 0) each time. But the overall effect is the same: start- +ing from the smallest element, each time the element size is increased by |𝑟𝑎𝑡𝑖𝑜|. +respectively; +Example: +1. This example below generates a regular box mesh. Its size is 0.2 by 0.2 by 0.2. It is +generated in a local coordinate system defined by three nodes 2, 3, 4 and originates +from node 1. +The local 𝑥-axis mesh spacing is defined by control points ID 1001. It has 21 nodes +evenly distributed from 0.0 to 0.2. The local 𝑦-axis is defined by ID 1002 and has twice +the elements of 1001. It has 41 nodes evenly distributed from 0.0 to 0.2. The local 𝑧-axis +is defined by ID 1003. It has 31 nodes and covers from 0.0 to 0.2. The mesh is two times +finer in the region between node 6 and node 26. +*ALE_STRUCTURED_MESH +$ mshid dpid nbid ebid + 1 1 200001 200001 +$ cpidx cpidy cpidz nid0 lcsid + 1001 1002 1003 1 234 +*DEFINE_COORDINATE_NODES +$ cid nid1 nid2 nid3 + 234 2 3 4 +*ALE_STRUCTURED_MESH_CONTROL_POINTS + 1001 +$ x1 x2 + 1 .0 + 21 .2 +*ALE_STRUCTURED_MESH_CONTROL_POINTS + 1002 +$ x1 x2 + 1 .0 + 41 .2 +*ALE_STRUCTURED_MESH_CONTROL_POINTS + 1003 +$ x1 x2 + 1 .0 + 6 .05 + 26 .15 + 31 .2 +*NODE + 1 0.0000000e+00 0.0000000e+00 0.0000000e+00 + 2 0.0000000e+00 0.0000000e+00 0.0000000e+00 + 3 0.1000000e+00 0.0000000e+00 0.0000000e+00 + 4 0.0000000e+00 0.1000000e+00 0.0000000e+00 +*END +2. This example shows how to generate a progressive larger/smaller mesh spacing. +The mesh geometry is the same as the example above. At 𝑥-direction the mesh is +progressively smaller between node 1 and 8. For these 7 elements, each element is +0.1/1.1 = 9.09% smaller than its left neighbor. Between node 15 and node 22, the mesh +is progressively larger by 10% each time in those 7 elements. The 7 elements in the +middle between node 8 and 15 are of equal length. +*ALE_STRUCTURED_MESH +$ mshid dpid nbid ebid + 1 1 200001 200001 +$ cpidx cpidy cpidz nid0 lcsid + 1001 1002 1003 1 234 +*DEFINE_COORDINATE_NODES +$ cid nid1 nid2 nid3 + 234 2 3 4 +*ALE_STRUCTURED_MESH_CONTROL_POINTS + 1001 +$ x1 x2 ratio + 1 .0 -0.1 + 8 0.06666667 + 15 0.13333333 0.1 + 22 .2 +*ALE +Purpose: This keyword is to provide a convenient utility to refine existing meshes +generated by *ALE_STRUCTURED_MESH card. All the NODESET, ELEMENTSET +and SEGMENTSET defined using SALECPT and SALEFAC options in *SET_cards will +be automatically updated. This way, this card is the only modification in the input deck +for users to define a refined S-ALE mesh. +5 +6 +7 +8 + Card 1 +1 +2 +Variable +MSHID +IFX +Type +I +Default +none +I +1 +3 +IFY +I +1 +4 +IFZ +I +1 + VARIABLE +MSHID +IFX, IFY, IFZ +Remarks: +DESCRIPTION +S-ALE Mesh ID. The ID of the Structured ALE mesh to be +refined. +Refinement factor at each local direction. Please see +remark 1. +1. +IFX, IFY, IFZ prescribe how many times to refine the grid along each direction. +They have to be integers. +2. This keyword provides a new modeling technique to handle the multi-material +ALE problems. Compared to pure Lagrange problems, models contain multi- +material ALE fluids are often time consuming and memory demanding. So it is +better to construct a concept model with much coarse mesh to get an estimate of +the computational resources needed and refine the concept model mesh gradu- +ally until convergence is achieved. This keyword minimized the user effort +following such procedure. +Example: +This example below generates two regular evenly distributed box mesh. Each has 22 +nodes along each direction and the overall size is 0.2 by 0.2 by 0.2. S-ALE mesh 1 is +generated in a local coordinate system defined by three nodes 2,3,4 and originated from +node 1. +If at later times, we decided to make the mesh finer, we can simply add the following +card. Now the solid element set 100 would contain elements ranging between nodes +(1,1,23) and (45,45,45) instead of the original (1,1,11) and (22,22,22). +*ALE_STRUCTURED_MESH_REFINE +$ mshid ifx ify ifz + 1 2 2 2 +*ALE_STRUCTURED_MESH +$ mshid dpid nbid ebid + 1 1 200001 200001 +$ cpidx cpidy cpidz nid0 lcsid + 1001 1001 1001 1 234 +*DEFINE_COORDINATE_NODES +$ cid nid1 nid2 nid3 + 234 2 3 4 +*SET_SOLID_GENERAL +$ SID + 100 +$ OPTION MSHID XMN XMX YMN YMX ZMN +ZMX + SALECPT 1 1 22 1 22 11 22 +*ALE_STRUCTURED_MESH_CONTROL_POINTS + 1001 +$ x1 x2 + 1 .0 + 22 .2 +*NODE + 1 0.0000000e+00 0.0000000e+00 0.0000000e+00 + 2 0.0000000e+00 0.0000000e+00 0.0000000e+00 + 3 0.1000000e+00 0.0000000e+00 0.0000000e+00 + 4 0.0000000e+00 0.1000000e+00 0.0000000e+00 + 5 0.0000000e+00 0.0000000e+00 0.0000000e+00 +*END +*ALE +Purpose: This card changes a fraction of an ALE multi-material-group (AMMGID) into +another group. The fraction is to be specified by a *DEFINE_FUNCTION function. The +function take as many arguments as there are fields specified on the cards in format 2. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FR_MMG TO_MMG +IDFUNC +IDSEGSET IDSLDSET NCYCSEG NCYCSLD +Type +I +I +I +Default +none +none +None +I +0 +I +0 +I +I +50 +50 +Variable Cards. Cards defining the function arguments. Include as many cards as +necessary. This input ends at the next keyword (“*”) card. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +VAR +VAR +VAR +VAR +VAR +VAR +VAR +VAR +Type +Default +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 + VARIABLE +FR_MMG +TO_MMG +DESCRIPTION +This is the AMMG-SID before the switch. The AMMG-SID +corresponds to the SID defined on a *SET_MULTI-MATERIAL_- +GROUP_LIST (SMMGL) card. This SID refers to one or more +AMMGs. See Remark 1. +This is the AMMG-SID after the switch. The AMMG-SID +corresponds to the SID defined on a *SET_MULTI-MATERIAL_- +GROUP_LIST card. This SID refers to one or more AMMGs. See +Remark 1. +IDFUNC +ID of a *DEFINE_FUNCTION function. This function determines +the material fraction to be switched. See Example 1. +IDSEGSET +IDSLDSET +NCYCSEG +NCYCSLD +*ALE_SWITCH_MMG +DESCRIPTION +ID of *SEGMENT_SET that is used to pass geometric properties to +the function specified by IDFUNC. This field is optional. +The segment center positions and normal vectors are computed. +For each ALE element, this data is passed to the function +IDFUNC for the segment the closest to the element center. See +Example 2. +The ID of a *SOLID_SET specifying which elements are affected +by this particular instance of the *ALE_SWITCH_MMG keyword. +This field is optional. If undefined, *ALE_SWITCH_MMG affects +all ALE elements. The element centers are computed and can be +used as variables in the function IDFUNC. +Number of cycles between each update of the segment centers +and normal vectors (if a segment set is defined). For each update, +a bucket sort is applied to find the closest segment to each ALE +element. If the segment nodes are fully constrained, the segment +centers and normal vectors are computed only one time. +Number of cycles between each update of the ALE element +centers. For each update, a bucket sort is applied to find the +closest segment to each ALE element. If the element nodes does +not move (as with AFAC = -1 in *CONTROL_ALE) the element +centers are computed exactly once. +VAR +Variable rank in the following list : +EQ.0: +EQ.1: +EQ.2: +EQ.3: +EQ.4: +EQ.5: +EQ.6: +EQ.7: +EQ.8: +EQ.9: +See Remark 3 +𝑥𝑥-stress for FR_MMG +𝑦𝑦-stress for FR_MMG +𝑧𝑧-stress for FR_MMG +𝑥𝑦-stress for FR_MMG +𝑦𝑧-stress for FR_MMG +𝑧𝑥-stress for FR_MMG +plastic strain for FR_MMG +internal energy for FR_MMG +bulk viscosity for FR_MMG +EQ.10: +volume from previous cycle for FR_MMG +GE.11 and LE.20: +other auxiliary variables for FR_MMG +VARIABLE +DESCRIPTION +GE.21 and LE.40: +auxiliary variables for TO_MMG (𝑥𝑥- +stress, …) +EQ.41: +EQ.42: +EQ.43: +EQ.44: +EQ.45: +EQ.46: +EQ.47: +EQ.48: +EQ.49: +EQ.50: +EQ.51: +EQ.52: +EQ.53: +EQ.54: +EQ.55: +EQ.56: +EQ.57: +mass for FR_MMG +mass for TO_MMG +volume fraction for FR_MMG +volume fraction for TO_MMG +material volume for FR_MMG +material volume for TO_MMG +time +cycle +𝑥-position of the ALE element center +𝑦-position of the ALE element center +𝑧-position of the ALE element center +𝑥-position of the segment center +𝑦-position of the segment center +𝑧-position of the segment center +𝑥-component of the segment normal +𝑦-component of the segment normal +𝑧-component of the segment normal +GE.58 and LE.65: +𝑥-positions of the ALE nodes +GE.66 and LE.69: +𝑥-positions of the segment nodes +GE.70 and LE.77: +𝑦-positions of the ALE nodes +GE.79 and LE.81: +𝑦-positions of the segment nodes +GE.83 and LE.89: +𝑧-positions of the ALE nodes +GE.90 and LE.93: +𝑧-positions of the segment nodes +GE.94 and LE.101: 𝑥-velocities of the ALE nodes +GE.102 and LE.105: 𝑥-velocities of the segment nodes +GE.106 and LE.113: 𝑦-velocities of the ALE nodes +GE.114 and LE.117: 𝑦-velocities of the segment nodes +GE.118 and LE.125: 𝑧-velocities of the ALE nodes +GE.126 and LE.129: 𝑧-velocities of the segment nodes +VARIABLE +DESCRIPTION +GE.130 and LE.137: 𝑥-accelerations of the ALE nodes +GE.138 and LE.141: 𝑥-accelerations of the segment nodes +GE.142 and LE.149: 𝑦-accelerations of the ALE nodes +GE.150 and LE.153: 𝑦-accelerations of the segment nodes +GE.154 and LE.161: 𝑧-accelerations of the ALE nodes +GE.162 and LE.165: 𝑧-accelerations of the segment nodes +GE.166 and LE.173: masses of the ALE nodes +GE.174 and LE.177: masses of the segment nodes +EQ.178: +EQ.179: +EQ.180: +rank of the variable updated by the +function +rank of the multi-material group in the set +time step +Remarks: +1. Mapping. The multi-material group sets that are specified by the fields +FR_MMG and TO_MMG must be of the same length. Multi-material groups +are switched so that, for instance, the fourth multi-material group in the set +FR_MMG is mapped to the fourth multi-material group in the set TO_MMG. +. +2. Variable Specification. The variables are presented to the function IDFUNC +as floating point data. The order of the arguments appearing in the *DEFINE_- +FUNCTION should match the order of variable ranks VAR specified on Card 2 +(for this keyword). For example, when there is one card in format 2 containing +“47, 48, 41, 42”, then the time (47), the cycle (48), and the masses (41 & 42) +should be the first, second, third, and fourth arguments to the function defined +on the *DEFINE_FUNCTION keyword. +If there is a blank column between 2 variable ranks, the list between these 2 +ranks is specified. For example, if the card contains “1, ,6”, then the 6 stresses (1 +through 6) are selected as arguments . In the case that there are +several groups in the sets, if a variable rank VAR is repeated, the correspond- +ing variable will be defined in the function for each group. For instance, if the +sets have 3 groups and the volume fractions of the 2 first groups in the set +TO_MMG are required as arguments of the function, a card in format 2 should +have “44,44”. +3. Variable Update for Several Groups. If there is more than one group in the +set, the function is called for each group. For a given group with a rank in the +set > 1 (VAR=179), some variables including the volume fraction, mass, internal +energy may have been updated during the previous switches. If their original +values are required, they can be obtained by setting the first field (VAR) to 0. +4. Variable Update by the User. The variables can be updated by the user. If +VAR < 0 for some variables, the function is called again (after the switch) for +each of these variables. VAR = 178 gives the rank of the variable for which the +function is called. The function’s return value is taken as the new value for this +variable (instead of the fraction of material to switch). If the rank given by +VAR = 178 is zero, it means that the function is called for the switch. Only the +46 first variables 1 < VAR < 46, 58 < VAR < 165 and VAR = 180 can be modified. +Example 1: +The first example switches the material if the pressure is lower than a given value. +*comment +units: mks +Switch from the 3rd group to the 5th one if the pressure of the 3rd +group +is lower than pc : pres < pc +Do the same for the switch from 4th to 7th +If the switch occurs, the function frac returns 1.0. So the whole +material is permuted. +xxsig +: +xx-stress +of +the +groups +in +the +1st +*set_multi- +material_group_list +yysig +: +yy-stress +of +the +groups +in +the +1st +*set_multi- +material_group_list +zzsig +: +zz-stress +of +the +groups +in +the +1st +*set_multi- +material_group_list +pres : pressure +pc : pressure cutoff +*ALE_SWITCH_MMG +$# fr_mmg to_mmg idfunc idsegset idsldset ncycseg ncycsld + 1 2 10 + 1 2 3 +*set_multi-material_group_list +1 +3,4 +*set_multi-material_group_list +2 +5,7 +*DEFINE_FUNCTION +10 +float frac(float xxsig, float yysig, float zzsig) +{ + float pc; + pres = -(xxsig+yysig+zzsig)/3.0; +pc = -1000; + if (pres < pc) { + return 1.0; + } else { + return 0.0; + } + } +Example 2: +The second example switches the material if it goes through a segment. +*comment +units: mks +Switch the 1st group to the 2nd group if the ALE element center goes +through a segment of the set defined by idsegset = 1. +The segment position is updated every cycle +A fraction of the material is switched. This fraction depends on the +distance between the segment and element centers +time : 47th variable +cycle : 48th variable +xsld : 49th variable (x-position of the element center) +ysld : 50th variable (y-position of the element center) +zsld : 51th variable (z-position of the element center) +xseg : 52th variable (x-position of the segment center) +yseg : 53th variable (y-position of the segment center) +zseg : 54th variable (z-position of the segment center) +xn : 55th variable (x-component of the segment normal) +yn : 56th variable (y-component of the segment normal) +zn : 57th variable (z-component of the segment normal) +volmat1 : 43th variable (material volume of the 1st group) +volfrac1: 45th variable (volume fraction of the 1st group) +segsurf : segment surface (given by 0.5*sqrt(xn*xn+yn*yn+zn*zn)) +sldvol : ALE element volume (given by volmat1/volfrac1) +segcharaclen: characteristic length for the segment +sldcharaclen: characteristic length for the solid +xseg2sld: x-component of the vector segment center to element center +yseg2sld: y-component of the vector segment center to element center +zseg2sld: z-component of the vector segment center to element center +distnormseg2sld: Distance segment-element projected on the normal +disttangseg2sld: Distance segment-element projected on the segment plane +*ALE_SWITCH_MMG +$# fr_mmg to_mmg idfunc idsegset idsldset ncycseg ncycsld + 1 2 11 1 1 + 47 57 43 45 +*set_multi-material_group_list +1 +1 +*set_multi-material_group_list +2 +2 +*DEFINE_FUNCTION +11 +float switchmmg(float time, float cycle, + float xsld, float ysld, float zsld, +float xseg, float yseg, float zseg, + float xn, float yn, float zn, + float volmat1, float volfrac1) +{ + float segsurf, sldvol, segcharaclen, sldcharaclen; + float xseg2sld, yseg2sld, zseg2sld, distnormseg2sld; + float xtangseg2sld, ytangseg2sld, ztangseg2sld, disttangseg2sld; + float frac; + segsurf = sqrt(xn*xn+yn*yn+zn*zn); + if (segsurf != 0.0) { + xn = xn/segsurf; + yn = yn/segsurf; + zn = zn/segsurf; + } + segsurf = 0.5*segsurf; + sldvol = volmat1/volfrac1; + segcharaclen = 0.5*sqrt(segsurf); + sldcharaclen = 0.5*sldvol**(1.0/3.0); + xseg2sld = xsld-xseg; + yseg2sld = ysld-yseg; + zseg2sld = zsld-zseg; + distnormseg2sld = xseg2sld*xn+yseg2sld*yn+zseg2sld*zn; + xtangseg2sld = xseg2sld-distnormseg2sld*xn; + ytangseg2sld = yseg2sld-distnormseg2sld*yn; + ztangseg2sld = zseg2sld-distnormseg2sld*zn; + disttangseg2sld = xtangseg2sld*xtangseg2sld+ + ytangseg2sld*ytangseg2sld+ + ztangseg2sld*ztangseg2sld; + disttangseg2sld = sqrt(disttangseg2sld); + if (disttangseg2sld <= segcharaclen && + distnormseg2sld <= sldcharaclen) { + sldcharaclen = 2.0*sldcharaclen; + frac = distnormseg2sld/sldcharaclen; + frac = 0.5-frac; + return frac; + } else { + return 0.0; + } +} +*ALE_TANK_TEST +Purpose: Control volume airbags (*AIRBAG_) only require two engineering curves to +define gas inflator, i.e. 𝑚̇ (𝑡) and 𝑇̅̅̅̅̅ +gas(𝑡); those two curves can be experimentally +measured. However, the ALE inflator needs one additional state variable - the inlet gas +velocity which is impractical to obtain. This keyword is to provide such curve through +an engineering approximation. +It takes two curves from the accompanying *SECTION_POINT_SOURCE as input. It +assumes inflator gas under choking condition to generate velocity curve. During this +process, the original curves, 𝑚̇ (𝑡) and 𝑇̅̅̅̅̅ +gas(𝑡), are modified accordingly. +It complements and must be used together with the*SECTION_POINT_SOURCE +command. Please see *SECTION_POINT_SOURCE for additional information. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable MDOTLC +TANKV +PAMB +PFINAL MACHL +VELMAX +AORIF +Type +Default +I +0 +I +I +I +F +F +F +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +AMGIDG +AMGIDA NUMPNT +Type +Default +I +0 +I +0 +I +50 + VARIABLE +MDOTLC +TANKV +DESCRIPTION +LCID for mass flow rate as a function of time. This may be +obtained directly from the control-volume type input data. +Volume of the tank used in a tank test from which the tank +pressure is measured, and 𝑚̇ (𝑡) and 𝑇̅̅̅̅gas(𝑡) are computed from +this tank pressure data. +VARIABLE +DESCRIPTION +PAMB +The pressure inside the tank before jetting (usually 1bar). +PFINAL +The final equilibrated pressure inside the tank from the tank test. +MACHL +VELMAX +AORIF +A limiting MACH number for the gas at the throat (MACH = 1 +preferred). +Maximum allowable gas velocity across the inflator orifice (not +preferred). +Total inflator orifice area (optional, only needed if the *SEC- +TION_POINT_SOURCE card is not used). +AMGIDG +The ALE multi-material group ID (AMMGID) of the gas. +AMGIDA +The ALE multi-material group ID (AMMGID) of the air. +NUMPNT +The number of points +NUMPNT = 0, defaults to 50 points. +in 𝑚̇ (𝑡) and 𝑇̅̅̅̅gas(𝑡) curves. + If +Remarks: +In an airbag inflator tank test, the tank pressure data is measured. This pressure is used +to derive 𝑚̇ (𝑡) and to estimate 𝑇̅̅̅̅gas(𝑡), the stagnation temperature of the inflator gas. +This is done by applying a lumped-parameter method to the system of conservation +equations using an equation of state. +Together 𝑚̇ (𝑡) and 𝑇̅̅̅̅gas(𝑡) provide enough information to model an airbag with the +control volume method . However, for an ALE or Eulerian fluid- +structure interaction analysis, the gas velocity, ���(𝑡), and density, 𝜌(𝑡), at the inlet must +be computed. But, since only 𝑚̇ (𝑡) is known, additional assumptions must be made +about the inlet conditions. If 𝑣(𝑡) and 𝜌(𝑡) are calculated outside of LS-DYNA, then LS- +DYNA combines them with 𝑚̇ (𝑡) and 𝑇̅̅̅̅gas(𝑡) to obtain 𝑇̅̅̅̅gas corrected(𝑡), 𝑣(𝑡) and 𝜌(𝑡) +which are sufficient input for an ALE calculation. +The curves 𝑣(𝑡) and 𝜌(𝑡) need not be calculated outside of LS-DYNA as LS-DYNA +features a method for calculating them itself. This card, *ALE_TANK_TEST, activates +this capability. Thus, with the combination of this card and the *SECTION_POINT_- +SOURCE card, LS-DYNA can proceed directly from the control volume method input, +𝑚̇ (𝑡) and 𝑇̅̅̅̅gas(𝑡), to an ALE or Eulerian fluid-structure interaction analysis. The user +does not have to do the conversion himself. +If the *ALE_TANK_TEST card is present: +1. The definitions of the relative volume, 𝑉(𝑡), and the velocity, 𝑣(𝑡), curves in the +*SECTION_POINT_SOURCE card will be ignored in favor of those computed +by LS-DYNA. +2. The 𝑚̇ (𝑡)curve is read in on *ALE_TANK_TEST card. +3. The 𝑇gas(𝑡) curve (stagnation temperature), as opposed to 𝑇gas corrected(𝑡), is read +in on *SECTION_POINT_SOURCE card. +There is a subtle, but important, distinction between the two temperatures. +𝑇gas(𝑡) is derived directly from the tank pressure data based on a lump- +parameter approach, whereas 𝑇gas corrected(𝑡) is computed from 𝑚̇ (𝑡) and 𝑇gas(𝑡) +with additional isentropic and sonic flow assumptions for the maximum veloci- +ty at an orifice. 𝑇gas corrected(𝑡) is most appropriately interpreted as the static +temperature. These assumptions provide a necessary and physically reasonable +supplement to the governing equation, +𝑚̇ (𝑡) = 𝜌(𝑡)𝑣(𝑡)𝐴 +in which only𝑚̇ (𝑡) and 𝐴 are known leaving two parameters: 𝜌(𝑡), and 𝑣(𝑡) as +unkown. +4. The inflator area is computed from the *SECTION_POINT_SOURCE card that +has the AMMGID of the inflator gas in the *ALE_TANK_TEST card. If the +*BOUNDARY_AMBIENT_EOS card is used instead of the *SECTION_POINT_- +SOURCE card, then the area may be input in this *ALE_TANK_TEST card. +5. The reference density of the propellant “gas”, 𝜌0, is computed internally and +automatically used for the calculation. The 𝜌0 value from the *MAT_NULL +card is ignored. +Example: +Consider a tank test model consists of the inflator gas (PID 1) and the air inside the tank +(PID 2). The following information from the control volume model is available: +• 𝑚̇ (𝑡) (LCID 1 is from control volume model input). +• 𝑇̅̅̅̅gas(𝑡) (LCID 2 is from control volume model input). +• Volume of the tank used in the inflator tank test. +• Final equilibrated pressure inside the tank. +• Ambient pressure in the air. +Also available are: +• The nodal IDs of the nodes defining the orifice holes through which the gas flows +into the tank. +• The area associated with each hole (the node is assumed to be at the center of this +area). +• The vector associated with each hole defining the direction of flow. +In the input below LCID 1 and 2 are 𝑚̇ (𝑡) and 𝑇̅̅̅̅gas(𝑡), respectively. LCID 4 and 5 will be +ignored when the *ALE_TANK_TEST card is present. If it is not present, all 3 curves in +the *SECTION_POINT_SOURCE card will be used. When the *SECTION_POINT_- +SOURCE card is present, the element formulation is equivalent to an ELFORM = 11. +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|...8 +*PART +inflator gas +$ PID SECID MID EOSID HGID GRAV ADPOPT TMID + 1 1 1 0 0 0 0 0 +*PART +air inside the tank +$ PID SECID MID EOSID HGID GRAV ADPOPT TMID + 2 2 2 0 0 0 0 0 +*SECTION_SOLID +$ SECID ELFORM AET + 2 11 0 +*ALE_MULTI-MATERIAL_GROUP +$ SID SIDTYPE + 1 1 + 2 1 +*SECTION_POINT_SOURCE +$ SECID LCIDT LCIDVOLR LCIDVEL <= 3 curves in tempvolrvel.k file + 1 2 4 5 +$ NODEID VECTID AREA + 24485 3 15.066 + ... + 24557 3 15.066 +*ALE_TANK_TEST +$ MDOTLC TANKV PAMB PFINAL MACHL VELMAX AORIF + 1 6.0E7 1.0E-4 5.288E-4 1.0 0.0 +$ AMGIDG AMGIDA NUMPNT + 1 2 80 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|...8 +*ALE_UP_SWITCH +Purpose: For the simulation of airbag inflation process, this card allows the switching +from an ALE computation to a control volume (CV) or uniform pressure (UP) method +at a user-defined switch time. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +UPID +SWTIME +F +1.0e+16 +Type +Default +Remark +I +0 +1 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FSI_ID1 +FSI_ID2 +FSI_ID3 +FSI_ID4 +FSI_ID5 +FSI_ID6 +FSI_ID7 +FSI_ID8 +Type +Default +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +Additional card for UPID = 0 (or not defined). +Optional 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SID +SIDTYPE MMGAIR MMGGAS +Type +Default +I +0 +I +0 +I +0 +I +VARIABLE +UPID +DESCRIPTION +An ID defines a corresponding *AIRBAG_HYBRID_ID card for +use in an ALE-method-switching-to-CV-method simulation. The +simulation starts with ALE computational method, then switches +to a CV (or UP) method at some given time. +EQ.0: (or blank) The code will construct an equivalent +*AIRBAG_HYBRID_ID card automatically internally, +(default). The 3rd optional line is then a required input. +NE.0: An ID points to a corresponding *AIRBAG_HYBRID_ID +card which must be defined for use after the switch. If +UPID is defined, do not define the 3rd optional card. +SWTIME +The time at which the computation does a switch from an ALE- +method-to-CV-method. +FSI_ID1, …, +FSI_ID8 +Coupling IDs for one or more ALE fluid-structure-interaction +(FSI) +cards. +*CONSTRAINED_LAGRANGE_IN_SOLID_ID +These couplings are deleted during the 2nd, CV computational +phase. +SID +A set ID defines the Lagrangian parts which make up the airbag. +SIDTYPE +Set ID type for the above SETID (following the conventions in +*AIRBAG_HYBRID card). +EQ.0: SID is a segment set ID (SGSID). +NE.0: SID is a part set ID (PSID). +MMGAIR +The AMMG (ALE multi-material group) ID of surrounding air. +MMGGAS +The AMMG ID of inflator gas injected into the airbag. +Remarks: +1. +If UPID is zero or blank, optional card 3 must be defined. LSDYNA will +construct an equivalent *AIRBAG_HYBRID_ID card automatically. +*ALE_UP_SWITCH +Consider an airbag model with a 2-phase simulation: an ALE calculation being +switched to a CV method. During the CV phase, the simulation is defined by an +*AIRBAG_HYBRID_ID card. +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*ALE_UP_SWITCH +$ UP_ID SW_time + 100000 2.0000 +$ FSI_ID_1 FSI_ID_2 FSI_ID_3 FSI_ID_4 FSI_ID_5 FSI_ID_6 FSI_ID_7 FSI_ID_8 + 1 2 +$------------------------------------------------------------------------------- +*AIRBAG_HYBRID_ID +$ ID + 100000 +$ SID SIDTYP RBID VSCA PSCA VINI MWD SPSF + 2 1 0 1.0 1.0 0.0 0.0 0.0 +$ 2 ATMT ATMP ATMD GC CC + 293. 1.0130e-4 1.200E-9 8.3143 1. +$ C23 LCC23 A23 LCA23 CP23 LCP23 AP23 LCAP23 +$ OPT PVENT NGAS + 4 +$bac LCIDM LCIDT NOTUSED MW INITM A B C + 1001 1002 0.0288691 1.0 28.98 +$ FMASS +$air LCIDM LCIDT NOTUSED MW INITM A B C + 1600 1603 28.97E-3 0.0 26.38 8.178e-3 -1.612e-6 +$ FMASS +$pyroLCIDM LCIDT NOTUSED MW INITM A B C + 1601 1603 43.45E-3 0.0 32.87 2.127e-2 -5.193E-6 +$ FMASS +$sto_LCIDM LCIDT NOTUSED MW INITM A B C + 1602 1603 39.49E-3 0.0 22.41 2.865e-3 -6.995e-7 +$ FMASS +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +Example 2: +Consider the same airbag model with the same 2-phase simulation. However, all the +*AIRBAG_HYBRID_ID card definitions are extracted automatically from the ALE +model. There is no need to define the *AIRBAG_HYBRID_ID card. The 3rd optional +card is required. +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*ALE_UP_SWITCH +$ UP_ID SW_time +$ 100000 2.0000 + 0 2.0000 +$ FSI_ID_1 FSI_ID_2 FSI_ID_3 FSI_ID_4 FSI_ID_5 FSI_ID_6 FSI_ID_7 FSI_ID_8 + 1 2 +$ SETID SETYPE MMG_AIR MMG_GAS + 2 1 2 1 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +The keyword *BOUNDARY provides a way of defining imposed motions on boundary +nodes. The keyword control cards in this section are defined in alphabetical order: +*BOUNDARY_ACOUSTIC_COUPLING +*BOUNDARY_ACOUSTIC_IMPEDANCE +*BOUNDARY_ACOUSTIC_MAPPING +*BOUNDARY_ALE_MAPPING +*BOUNDARY_AMBIENT +*BOUNDARY_AMBIENT_EOS +*BOUNDARY_CONVECTION_OPTION +*BOUNDARY_COUPLED +*BOUNDARY_CYCLIC +*BOUNDARY_DE_NON_REFELECTING +*BOUNDARY_ELEMENT_METHOD_OPTION +*BOUNDARY_FLUX_OPTION +*BOUNDARY_MCOL +*BOUNDARY_NON_REFLECTING +*BOUNDARY_NON_REFLECTING_2D +*BOUNDARY_PAP +*BOUNDARY_PORE_FLUID_OPTION +*BOUNDARY_PRECRACK +*BOUNDARY_PRESCRIBED_ACCELEROMETER_RIGID +*BOUNDARY_PRESCRIBED_FINAL_GEOMETRY +*BOUNDARY_PRESCRIBED_MOTION_{OPTION1}_{OPTION2} +*BOUNDARY_PRESCRIBED_ORIENTATION_RIGID_OPTION +*BOUNDARY_PWP_OPTION +*BOUNDARY_RADIATION_OPTION +*BOUNDARY_SLIDING_PLANE +*BOUNDARY_SPC_{OPTION1}_{OPTION2}_{OPTION3} +*BOUNDARY_SPC_SYMMETRY_PLANE_OPTION +*BOUNDARY_SPH_FLOW +*BOUNDARY_SPH_NON_REFLECTING +*BOUNDARY_SPH_SYMMETRY_PLANE +*BOUNDARY_SYMMETRY_FAILURE +*BOUNDARY_TEMPERATURE_OPTION +*BOUNDARY_THERMAL_BULKFLOW_{OPTION1}_{OPTION2} +*BOUNDARY_THERMAL_BULKNODE +*BOUNDARY_THERMAL_WELD +*BOUNDARY_THERMAL_WELD_TRAJECTORY +*BOUNDARY_USA_SURFACE +*BOUNDARY_ACOUSTIC_COUPLING_{OPTION} +There are two forms of this keyword command: +1. +for coupling of surfaces with coincident nodes +*BOUNDARY_ACOUSTIC_COUPLING +2. +for coupling surfaces without coincident nodes +*BOUNDARY_ACOUSTIC_COUPLING_MISMATCH +Purpose: Define a segment set for acoustic coupling of structural element faces and +acoustic volume elements (type 8 and type 14 solid elements.) +If the mismatch option is not used, then this command couples either one side of a shell +or solid element structure or both sides of a shell structure to acoustic elements. The +segments in the segment set should define the structural surface for which coupling is +intended. The nodal points of the structural segments must be coincident with the +nodal points for the fluid element faces on either side of the structural segments. If +fluid exists on just one side of the structural segments, and the nodes are merged, then +the input data in this section is not required. The coupling will happen automatically. +However, if fluid is on both sides of the structural segments, then this input data is +required and the nodes should not be merged; two-sided coupling will not properly +apply loads when the interface nodes are merged out. +If the mismatch option is used, then this command permits the coupling of acoustic +fluid volume elements with one side of a structural element when the meshes of the +fluid and structural models are moderately mismatched. In this case, it is possible that +most fluid and structural nodes will not be coincident. None of the fluid and structural +nodes at the interface should be merged together. The segments in the segment set +should define the structural surface and, following a right hand rule, the normal vector +for the segments should point at the fluid volume elements with which coupling is +intended. If coupling is required on both sides of a structural shell element, duplicate +segments with opposite normal vectors should be defined. Every segment in the +segment set must couple with the fluid volume at some integration point, but it is not +necessary that all integration points on the segment couple with the fluid. The meshes +do not have to be mismatched to use mismatched coupling, as long as the fluid and +structural nodes are not merged. +Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SSID +Type +I +Default +none + VARIABLE +DESCRIPTION +SSID +Segment set ID, see *SET_SEGMENT +Remarks: +1. For the stability of the acoustic-structure coupling, the following condition must +be satisfied: +2𝜌𝑎𝐷 +𝜌𝑠𝑡𝑠 +< 5 +where 𝜌𝑎 is the density of the acoustic medium, 𝐷 is the total thickness of the +acoustic elements adjacent to the structural element, 𝜌𝑠 is the density, and 𝑡𝑠 is +the thickness of the structural shell element. If the structural element is a solid +or thick shell element, then ts should be half the thickness of the element. If +coupling is on both sides of the structural elements, then ts should also be half +the thickness of the structural element. +2. +In mismatched coupling, free fluid faces are considered for coupling with the +structural segments if they are near one another and if they face each other. +Faces and segments that differ in orientation by more than 45 degrees are ex- +cluded. In regions of high curvature the surfaces therefore need to be more +similar than when the surfaces are flat. If a fluid face couples with any struc- +tural segment, then all four integration points on the fluid face must couple +with some structural segment. Fluid faces may not be partially coupled. Struc- +tural segments are allowed to be partially coupled. +3. The mismatched coupling process dumps two LS-DYNA files that can be +imported into LS-PrePost for review of the results of the coupling process. File +“bac_str_coupling.dyn” contains shell elements where structural segments have +coupled with the fluid and mass elements at structural integration points with +coupling. When the messag file indicates that some structural segments have +partial coupling, this file can be used to check the unconnected segment integra- +tion points. File “bac_flu_coupling.dyn” contains shell elements where free +fluid faces have coupled with the structural segments and mass elements at free +fluid face integration points with coupling. These files are only for visualiza- +tion of the coupling and serve no other purpose. +*BOUNDARY_ACOUSTIC_IMPEDANCE +Purpose: Define a segment set to prescribe the acoustic impedance of acoustic volume +element (type 8 and type 14 solid elements) faces. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SSID +ZEE +Type +I +F +Default +none +none + VARIABLE +DESCRIPTION +Segment set ID, see *SET_SEGMENT +Value of the acoustic impedance ρc +SSID +ZEE +Remarks: +1. The effect of the boundary impedance on the acoustic cavity response is +incorporated in the forcing vector. Solutions are conditionally stable, with low +values of impedance relative to the impedance of the *MAT_ACOUSTIC ele- +ments causing instabilities. Reducing the factor of safety on the time step ex- +tends the range of applicability, however it is recommended that pressure +release conditions be handled by leaving the boundary free rather than by +providing a relatively low boundary acoustic impedance value. A warning is +issued if the boundary impedance value is less than 25 percent of the *MAT_- +ACOUSTIC impedance. A value less than 1 percent of the *MAT_ACOUSTIC +impedance is considered to be an error. + Special allowance is made for cases when both *LOAD_SEGMENT set +pressures and the *BOUNDARY_ACOUSTIC_IMPEDANCE are defined on the +same segments. In this event a nonreflecting entrant boundary condition is +assumed. The pressures in the LOAD_SEGMENT_SET definition are treated as +incoming incident pressure. Pressure waves within the *MAT_ACOUSTIC +domain striking this boundary will exit the model. In contrast, a *LOAD_SEG- +MENT_SET on *MAT_ACOUSTIC volume faces in the absence of *BOUND- +ARY_ACOUSTIC_IMPEDANCE acts as a time-dependent, total pressure +constraint and pressure waves within the *MAT_ACOUSTIC domain striking +this boundary will be reflected back into the model. +2. +*BOUNDARY_ACOUSTIC_MAPPING +Purpose: Define a set of elements or segments on structure for mapping structural +nodal velocity to acoustic volume boundary. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SSID +STYP +Type +I +Default +none +I +0 + VARIABLE +DESCRIPTION +SSID +STYP +Set or part ID +Set type: +EQ.0: part set ID, see *SET_PART, +EQ.1: part ID, see *PART, +EQ.2: segment set ID, see *SET_SEGMENT. +Remarks: +1. +If acoustic elements are not overlapping with structural elements, this keyword +passes structural velocity to acoustic volume boundary, for subsequent fre- +quency domain acoustic computation. +*BOUNDARY_ALE_MAPPING +Purpose: This card maps ALE data histories from a previous run to a region of +elements. Data are read or written in a mapping file called by the prompt “map=” on +the command line . To map data at the initial time (not the +histories) to all the ALE domain (not just a region of elements) see *INITIAL_ALE_- +MAPPING. +The following transitions are allowed: +1D → 2D +1D → 3D +2D → 2D +2D → 3D +3D → 3D + Card 1 +Variable +1 +ID +2 +3 +4 +5 +6 +7 +TYP +AMMSID +IVOLTYP +BIRTH +DEATH +DTOUT +Type +I +I +I +I +F +F +F +Default +none +none +none +none +0.0 +1020 + Card 2 +1 +2 +Variable +THICK +RADIUS +Type +F +F +3 +X1 +F +4 +Y1 +F +5 +Z1 +F +6 +X2 +F +time +step +7 +Y2 +F +8 +INI +I +0 +8 +Z2 +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 3 +Variable +1 +XO +Type +F +2 +YO +F +3 +ZO +F +4 +5 +6 +7 +8 +VECID +I +Default +0.0 +0.0 +0.0 +none +VARIABLE +DESCRIPTION +ID +TYP +Part ID or part set ID or element set ID +Type of “ID” : +EQ.0: part set ID. +EQ.1: part ID. +EQ.2: shell set ID. +EQ.3: solid set ID. +AMMSID +IVOLTYP +Set ID of ALE multi-material groups defined in *SET_MULTI- +MATERIAL_GROUP. See Remark 1. +Type of volume containing the selected elements for the mapping. +The absolute value of IVOLTYPE indicates the type of volume +and the sign indicates whether the data is being read of written. +Volume Type +|IVOLTYP|.EQ.1: Spherical surface with thickness (THICK). +|IVOLTYP|.EQ.2: Box. +|IVOLTYP|.EQ.3: Cylindrical surface with thickness (THICK) +|IVOLTYP|.EQ.4: All the elements defined by ID. +Read/Write +IVOLTYP.LT.0: data from the mapping file are read for the +elements of this volume. +IVOLTYP.GT.0: data from the elements of this volume are +written in the mapping file. +BIRTH +DEATH +Birth time to write or read the mapping file. If a mapping file is +written, the next run reading this file will begin at time BIRTH if +this parameter for this next run is not larger. +Death time to write or read the mapping file. If a mapping file is +written, the next run will stop to read this file at time DEATH if +this parameter for this next run is not smaller. +DTOUT +Time interval between outputs in the mapping file. This +parameter is only used to write in the mapping file. +VARIABLE +DESCRIPTION +INI +Flag to initialize all the ALE domain of the next run: +EQ.0: No initialization +EQ.1: Initialization. *INITIAL_ALE_MAPPING will have to be +in the input deck of the next run to read the data from +the mapping file. The initial time of the next run will be +BIRTH. +THICK +Thickness for the element selection using surfaces. +RADIUS +Radius for abs(IVOLTYP) = 1 and abs(IVOLTYP) = 3. +If abs(IVOLTYP).EQ.1: +X1 +Y1 +Z1 +X1 is the 𝑥-coordinate of the sphere center. +Y1 is the 𝑦-coordinate of the sphere center. +Z1 is the 𝑧-coordinate of the sphere center. +X2, Y2, Z2 +Ignored +If abs(IVOLTYP).EQ.2: +X1 +Y1 +Z1 +X2 +Y2 +Z2 +X1 is the 𝑥-coordinate of the box’s minimum point. +Y1 is the 𝑦-coordinate of the box’s minimum point. +Z1 is the 𝑧-coordinate of the box’s minimum point. +X2 is the 𝑥-coordinate of the box’s maximum point. +Y2 is the 𝑦-coordinate of the box’s maximum point. +Z2 is the 𝑧-coordinate of the box’s maximum point. +VARIABLE +DESCRIPTION +If abs(IVOLTYP).EQ.3: +X1 +Y1 +Z1 +X2 +Y2 +Z2 +X1 is the 𝑥-coordinate of a point on the cylinder’s axis. +Y1 is the 𝑦-coordinate of a point on the cylinder’s axis. +Z1 is the 𝑧-coordinate of a point on the cylinder’s axis. +X2 is the 𝑥-coordinate of a vector parallel to the cylinder’s axis. +Y2 is the 𝑦-coordinate of a vector parallel to the cylinder’s axis. +Z2 is the 𝑧-coordinate of a vector parallel to the cylinder’s axis. +If abs(IVOLTYP).EQ.4: +X1, Y1, Z1 +ignored +X2, Y2, Z2 +ignored +End if +X0 +Y0 +Z0 +Origin position in global 𝑥-direction. See Remark 2. +Origin position in global 𝑦-direction. See Remark 2. +Origin position in global 𝑧-direction. See Remark 2. +VECID +ID of the symmetric axis defined by *DEFINE_VECTOR. See +Remark 3. +Remarks: +1. Mapping of Multi-Material Groups. The routines of this card need to know +which mesh will be initialized with the mapping data and more specifically +which multi-material groups. The first 2 parameters (ID and TYP) defines the +mesh and the third one (AMMSID) refer to the *SET_MULTI-MATERIAL_- +GROUP_LIST card. This card will define a list of material groups in the current +run. The rank in this list should match the rank of the multi-material groups +from the previous run (as a reminder the ranks of multi-material groups are +defined by *ALE_MULTI-MATERIAL_GROUP). For instance, if the previous +model has 3 groups, the current one has 5 groups, and the following mapping is +wanted: +The 1st group (previous) ⇒ the 3rd group (current), +The 2nd group (previous) ⇒ the 5th group (current) and, +The 3rd group (previous) ⇒ the 4th group (current). +Then, the *SET_MULTI-MATERIAL_GROUP_LIST card should be as follows: +*SET_MULTI-MATERIAL_GROUP_LIST +300 +3,5,4 +2. Origin. The data can be mapped in different parts of the mesh by defining the +origin of the coordinate system (X0, Y0, Z0). +3. Orientation Vector: VECID. For a mapping file created by a previous +asymmetric model, the symmetric axis orientation in the current model is speci- +fied by VECID. For a mapping file created by a 3D or 1D spherical model, the +vector VECID is read but ignored. The definitions of X0, Y0, Z0 and VECID +change in the case of the following mappings: +a) plain strain 2D (ELFORM = 13 in *SECTION_ALE2D) to plain strain 2D +b) plain strain 2D to 3D +While, VECID still defines the y-axis in the 2D domain, the 3 first parameters in +*DEFINE_VECTOR, additionally, define the location of the origin. The 3 last +parameters defines a position along the y-axis. For this case when 2D data is +used in a 3D calculation the point X0, Y0, Z0 together with the vector, VECID, +define the plane. +4. Mapping File. To make one mapping: only the command-line argument +“map=” is necessary. If IVOLTYP is positive, the mapping file will be created +and ALE data histories will be written in this file. If IVOLTYP is negative the +mapping file will be read and ALE data histories will be used to interpolate the +ALE variables of the selected elements. This file contains the following nodal +and element data: +• nodal coordinates +• nodal velocities +• part ids +• element connectivities +• element centers +• densities +• volume fractions +• stresses +• plastic strains +• internal energies +• bulk viscosities +• relative volumes +5. Successive Mappings. To make several successive mapping: the prompt +“map1=” is necessary. If IVOLTYP is positive and the prompt “map1=” is in +the command line, the ALE data are written to the mapping file given by +“map1=”. If IVOLTYP is negative and the prompt “map=” is in the command +line, ALE data are read from the mapping file given by “map=”. +*BOUNDARY_AMBIENT +Purpose: This command defines ALE “ambient” type element formulations +(please see Remarks 1, 2 and 5). + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SETID +MMG +AMBTYP +Type +I +I +I +Default +none +none +none +Optional Card. Additional optional card for AMBTYP = 4 with curves + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCID1 +LCID2 +Type +I +I +Default +none +none + VARIABLE +SETID +DESCRIPTION +The ambient element set ID for which the thermodynamic state is +being defined. The element set can be *SET_SOLID for a 3D ALE +model, *SET_SHELL for a 2D ALE model or *SET_BEAM for a 1D +ALE model. +MMG +ALE multi-material group ID. +AMBTYP +Ambient element type: +EQ.4: Pressure inflow/outflow +EQ.5: Receptor +for blast +load +DESCRIPTION +A load curve ID for internal energy per unit reference volume +(Please see Remark 4 and read the beginning of the EOS section +for details). If *EOS_IDEAL_GAS is being used, this ID then +refers to a temperature load curve ID. +Load curve ID for relative volume, 𝑣𝑟 = ( 𝑣 +𝑣0 +Remark 3 and read the beginning of the EOS section for details). +𝜌0 +𝜌 ). (Please see += + VARIABLE +LCID1 +LCID2 +Remarks: +1. The term “ambient” refers to a medium that has predetermined thermodynam- +ic state throughout the simulation. All “ambient” elements will have its ther- +modynamic state reset back to this predetermined state every cycle. If this state +is defined via the *EOS card, then this predetermined thermodynamic state is +constant throughout the simulation. If it is defined via the curves of the 2nd line +for AMBTYP = 4, its thermodynamic state will vary according to these defined +load curves. “Ambient” elements are sometimes also referred to as “reservoir” +elements as they may be used to simulate semi-infinite region. +2. +In general, a thermodynamic state of a non-reacting and no-phase-change +material may be defined by 2 thermodynamic variables. By defining (a) an +internal energy per unit reference volume load curve (or a temperature load +curve if using *EOS_IDEAL_GAS) and (b) a relative volume load curve, the +pressure as a function of time for this ambient part ID can be computed directly +via the equation of state (*EOS_…). +3. A reference specific volume, 𝑣0 = 1 +𝜌0 +, is the inverse of a reference density, 𝜌0. +The reference density is defined as the density at which the material is under a +reference or nominal state. Please refer to the *EOS section for additional ex- +planation on this. +4. The internal energy per unit reference volume may be defined as +𝑒ipv0 = +𝐶𝑣𝑇 +𝑣0 +. +The specific internal energy (or internal energy per unit mass) is defined as +𝐶𝜈𝑇. +5. This card does not require AET under *SECTION_SOLID or SECTION_ALE2D +or SECTION_ALE1D card +*BOUNDARY_AMBIENT_EOS +Purpose: This command defines the IDs of 2 load curves: (1) internal energy per unit +reference volume (or temperature if using *EOS_IDEAL_GAS) and (2) relative volume. +These 2 curves completely prescribe the thermodynamic state as a function of time for +any ALE or Eulerian part with an “ambient” type element formulation (please see +Remark 4). + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID +LCID1 +LCID2 +Type +I +I +I +Default +none +none +none + VARIABLE +DESCRIPTION +The ambient Part ID for which the thermodynamic state is being +defined. +Load curve ID (*DEFINE_CURVE or *DEFINE_CURVE_FUNC- +TION) for internal energy per unit reference volume (please read +the beginning of the EOS section for details). If *EOS_IDEAL_- +GAS is being used, this ID then refers to a temperature load curve +ID. +Load curve ID (*DEFINE_CURVE or *DEFINE_CURVE_FUNC- +𝜌0 +TION) for relative volume, 𝑣𝑟 = ( 𝑣 +𝜌 ). (Please read the += +𝑣0 +beginning of the EOS section for details). +PID +LCID1 +LCID2 +Remarks: +1. The term “ambient” refers to a medium that has predetermined thermodynam- +ic state throughout the simulation. All “ambient” parts/elements will have its +thermodynamic state reset back to this predetermined state every cycle. If this +state is defined via the *EOS card, then this predetermined thermodynamic +state is constant throughout the simulation. If it is defined via this card, +*BOUNDARY_AMBIENT_EOS, then its thermodynamic state will vary accord- +ing to these defined load curves. “Ambient” part is sometimes also referred to +as “reservoir” part as it may be used to simulate semi-infinite region. +2. +In general, a thermodynamic state of a non-reacting and no-phase-change +material may be defined by 2 thermodynamic variables. By defining (a) an +internal energy per unit reference volume load curve (or a temperature load +curve if using *EOS_IDEAL_GAS) and (b) a relative volume load curve, the +pressure as a function of time for this ambient part ID can be computed directly +via the equation of state (*EOS_…). +3. A reference specific volume, 𝑣0 = 1 +𝜌0 +, is the inverse of a reference density, 𝜌0. +The reference density is defined as the density at which the material is under a +reference or nominal state. Please refer to the *EOS section for additional ex- +planation on this. +4. The internal energy per unit reference volume may be defined as +𝑒ipv0 = +𝐶𝑣𝑇 +𝑣0 +. +The specific internal energy (or internal energy per unit mass) is defined as +𝐶𝜈𝑇. +5. This card is only to be used with “ambient” element type as defined by the +parameters under the *SECTION_SOLID card: +a) ELFORM = 7, or +b) ELFORM = 11 and AET = 4, or +c) ELFORM = 12 and AET = 4. +Example: +Consider an ambient ALE part ID 1 which has its internal energy per unit reference +volume in a load curve ID 2 and relative volume load curve ID 3: +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|...8 +*BOUNDARY_AMBIENT_EOS +$ PID e/T_LCID rvol_LCID + 1 2 3 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|...8 +*BOUNDARY_CONVECTION_OPTION +Available options include: +SEGMENT +SET +Purpose: Apply a convection boundary condition on a SEGMENT or SEGMENT_SET +for a thermal analysis. Two cards are defined for each option. +Card 1 for SET keyword option. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SSID +Type +I +Default +none +Card 1 for SEGMENT keyword option. + Card 1 +Variable +1 +N1 +Type +I +2 +N2 +I +3 +N3 +I +4 +N4 +I +Default +none +none +none +none +5 +6 +7 +8 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +HLCID +HMULT +TLCID +TMULT +LOC +Type +I +F +I +F +Default +none +0. +none +0. +I +VARIABLE +DESCRIPTION +SSID +Segment set ID, see *SET_SEGMENT. +N1, N2, …. +Node ID’s defining segment. +HLCID +Convection heat transfer coefficient, ℎ. This parameter can +reference a load curve ID or a function ID +. When the reference is +to a curve, HLCID has the following interpretation: +GT.0: ℎ is given as a function of time, 𝑡. The curve consists of +(𝑡, ℎ(𝑡)) data pairs. +EQ.0: ℎ is a constant defined by the value HMULT. +LT.0: ℎ is given as a function of temperature, 𝑇𝑓𝑖𝑙𝑚. The curve +consists of (𝑇𝑓𝑖𝑙𝑚, ℎ) data pairs. Enter |HLCID| on the +DEFINE_CURVE keyword. +HMULT +Convection heat transfer coefficient, ℎ, curve multiplier. +TLCID +Environment temperature, 𝑇∞. This parameter can reference a +load curve ID or a function ID . When the reference is to a +curve, TLCID has the following interpretation: +GT.0: 𝑇∞ is defined by a curve indexed by time consisting of +(𝑡, 𝑇∞(𝑡)) data pairs. +EQ.0: 𝑇∞ is a constant defined by the value TMULT. +TMULT +Environment temperature, 𝑇∞, curve multiplier. +LOC +For a thick thermal shell, the convection will be applied to the +surface identified by LOC. See parameter, THSHEL, on the +*CONTROL_SHELL keyword. +EQ.-1: lower surface of thermal shell element +EQ.0: middle surface of thermal shell element +EQ.1: upper surface of thermal shell element +Remarks: +1. A convection boundary condition is calculated using 𝑞 ̇′′ = ℎ(𝑇surface − 𝑇∞) +where h is the heat transfer coefficient, and 𝑇surface − 𝑇∞ is a temperature poten- +tial. If h is a function of temperature, h is evaluated at the average or “film” +temperature defined by + 𝑇𝑓𝑖𝑙𝑚 = (𝑇surface + 𝑇∞)/2.. +2. +If HLCID references a DEFINE_FUNCTION, the following function arguments +are allowed 𝑓 (𝑥, 𝑦, 𝑧, 𝑣𝑥, 𝑣𝑦, 𝑣𝑍, 𝑇, 𝑇∞, 𝑡) where: +𝑥, 𝑦, 𝑧 = segment centroid coordinates +𝑣𝑥, 𝑣𝑦, 𝑣𝑧 = segment centroid velocity component +𝑇 = segment centroid temperature +𝑇∞ = environment temperature, T∞ +���� = solution time +3. +If TLCID references a DEFINE_FUNCTION, the following function arguments +are allowed 𝑓 (𝑥, 𝑦, 𝑧, 𝑣𝑥, 𝑣𝑦, 𝑣𝑧, 𝑡) where: +𝑥, 𝑦, 𝑧 = segment centroid coordinates +𝑣𝑥, 𝑣𝑦, 𝑣𝑧 = segment centroid velocity components +𝑡 = solution time +*BOUNDARY +Purpose: Define a boundary that is coupled with an external program. Two cards are +required for each coupled boundary + Card 1 +Variable +1 +ID +Type +I +2 +3 +4 +5 +6 +7 +8 +TITLE +A70 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SET +TYPE +PROG +Type +I +I +I +Default +none +none +none + VARIABLE +DESCRIPTION +ID +ID for this coupled boundary +TITLE +Descriptive name for this boundary +SET +TYPE +Node set ID +Coupling type: +EQ.1: node set with force feedback +EQ.2: node set for multiscale spotwelds +PROG +Program to couple to +EQ.1: MPP-DYNA +Remarks: +This option is only available in the MPP version, and allows for loose coupling with +other MPI programs using a “multiple program” execution method. Currently it is +only useful when linking with MPP-DYNA for the modeling of multiscale spotwelds +(type = 2, prog = 1). See *INCLUDE_MULTISCALE_SPOTWELD for information about +using this capability. +*BOUNDARY +OPTION allows an optional ID to be given that applies each cyclic definition +ID +Purpose: Define nodes in boundary planes for cyclic symmetry. +These boundary conditions can be used to model a segment of an object that has +rotational symmetry such as an impeller, i.e., Figure 5-1. The segment boundary, +denoted as a side 1 and side 2, may be curved or planar. In this section, a paired list of +points are defined on the sides that are to be joined. +ID Card. Additional card for ID keyword option. +2 +3 +4 +5 +6 +7 +8 +ID +Variable +1 +ID +Type +I + Card 1 +Variable +1 +XC +Type +F +2 +YC +F +3 +ZC +F +HEADING +A70 +4 +5 +6 +7 +8 +NSID1 +NSID2 +IGLOBAL +ISORT +I +I +I +0 +I +0 +Default +none +none +none +none +none + VARIABLE +DESCRIPTION +XC +YC +ZC +x-component axis vector of axis of rotation +y-component axis vector of axis of rotation +z-component axis vector of axis of rotation +NSID1 +Node set ID for first boundary (side 1, see Figure 5-1). +Conformable +Interface +Side 1 +e 2 +Sid +Segment +Figure 5-1. With axi-symmetric cyclic symmetry, only one segment is +modeled. + VARIABLE +NSID2 +DESCRIPTION +Node set ID for second boundary (side 2, see Figure 5-1). Each +node in this set is constrained to its corresponding node in the +first node set. Node sets NSID1 and NSID2 must contain the +same number of nodal points. The shape of the two surfaces +formed by the two node sets need not be planar but the shapes +should match. +IGLOBAL +Flag for repeating symmetry: +EQ.0: Axi-symmetric cyclic symmetry (default) +EQ.1: Repeating symmetry in planes normal to global X +EQ.2: Repeating symmetry in planes normal to global Y +EQ.3: Repeating symmetry in planes normal to global Z +ISORT +Set to 1 for automatic sorting of nodes in node sets. See Remark 2. +Remarks: +1. Each node set should generally be boundaries of the model. +2. Prior to version 970, it was assumed that the nodes are correctly ordered within +each set, i.e. the nth node in NSID1 is equivalent to the nth node in NSID2. In +version 970 and later versions, if the ISORT flag is active, the nodes in NSID2 +are automatically sorted to achieve equivalence, so the nodes can be picked by +the quickest available method. However, for axi-symmetric cyclic symmetry +(IGLOBAL = 0), it is assumed that the axis passes through the origin, i.e., only +globally defined axes of rotation are possible. +*BOUNDARY_DE_NON_REFLECTING +Purpose: Define a non-reflecting boundary for discrete element. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NSID +Type +I +Default +none +Remarks +1, 2 + VARIABLE +DESCRIPTION +NSID +Node set ID, see *SET_SEGMENT. +Remarks: +1. Non-reflecting boundaries are used on the exterior boundaries of an analysis +model of an infinite domain, such as a half-space to prevent artificial stress +wave reflections generated at the model boundaries form reentering the model +and contaminating the results. +Available options include: +SEGMENT +SET +*BOUNDARY +Purpose: Apply a flux boundary condition on a SEGMENT or SEGMENT_SET for a +thermal analysis. Two or more cards are defined for each option. History variables can +be associated with the boundary condition which will invoke a call to a user defined +boundary flux subroutine for computing the flux. +Card 1 for SET option. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SSID +Type +I +Default +none +Card 1 for SEGMENT option. + Card 1 +Variable +1 +N1 +Type +I +2 +N2 +I +3 +N3 +I +4 +N4 +I +Default +none +none +none +none +5 +6 +7 +Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCID +MLC1 +MLC2 +MLC3 +MLC4 +LOC +NHISV +Type +I +F +Default +none +0. +F +0. +F +0. +F +0. +I +0 +I +0 +Define as many cards as necessary to initialize NHISV history variables. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +HISV1 +HISV2 +HISV3 +HISV4 +HISV5 +HISV6 +HISV7 +HISV8 +Type +F +Default +0. +F +0. +F +0. +F +0. +F +0. +F +0. +F +0. +F +0. + VARIABLE +DESCRIPTION +SSID +Segment set ID, see *SET_SEGMENT +N1, N2, … +Node IDs that define the segment +VARIABLE +LCID +DESCRIPTION +This parameter can reference a load curve ID or a function ID for heat flux. When the reference is to a curve, LCID has the +following interpretation: +GT.0: the flux is defined by a curve consisting of (time, flux) +data pairs using the DEFINE_CURVE keyword. The flux +value applied to the nodal points is the curve value mul- +tiplied by the values MLC1, MLC2, MLC3, and MLC4, +respectively. +EQ.0: a constant flux is applied to each node defined by the +values MLC1, MLC2, MLC3, and MLC4, respectively. +LT.0: the +flux +is defined by a curve consisting of +(temperature, flux) data pairs using the DEFINE_- +CURVE keyword. The flux value applied to the nodal +points is the curve value multiplied by the values MLC1, +MLC2, MLC3, and MLC4. Enter |-LCID| on the DE- +FINE_CURVE keyword. +MLC1 +MLC2 +MLC3 +MLC4 +LOC +Curve multiplier at node N1. +Curve multiplier at node N2. +Curve multiplier at node N3. +Curve multiplier at node N4. +For a thick thermal shell, the flux will be applied to the surface +identified by LOC. See parameter, THSHEL, on the *CON- +TROL_SHELL keyword. +EQ.-1: lower surface of thermal shell element +EQ.0: middle surface of thermal shell element +EQ.1: upper surface of thermal shell element +NHISV +Number of history variables associated with the flux definition: +GT.0: A user defined subroutine will be called to compute the +flux. See Remark 1. +HISV1 +HISV2 +Initial value of history variable 1 +Initial value of history variable 2 +VARIABLE +DESCRIPTION +⋮ +⋮ +HISVn +Initial value of history variable n, where n = NHISV +Remarks: +1. The segment normal has no bearing on the flux. A positive flux transfers +energy into the volume; a negative flux transfers energy out of the volume. +2. Flux can be defined by: +a) When LCID = 0, a constant flux is applied to each node defined by the +values MLC1, MLC2, MLC3, and MLC4, respectively. +b) When LCID > 0, the flux is defined by a curve consisting of (time, flux) +data pairs using the DEFINE_CURVE keyword. The flux value applied to +the nodal points is the curve value multiplied by the values MLC1, MLC2, +MLC3, and MLC4, respectively. +c) When LCID < 0, +the +flux +is defined by a curve consisting of +(temperature, flux) data pairs using the DEFINE_CURVE keyword. The +flux value applied to the nodal points is the curve value multiplied by the +values MLC1, MLC2, MLC3, and MLC4. Enter |LCID| on the DEFINE_- +CURVE keyword. +d) When NHSIV > 0, the user subroutine +subroutine usrflux(fl, flp, ...) +will be called to compute the heat flux (fl). For more details see Appen- +dix S. +e) If LCID references a DEFINE_FUNCTION, the following function argu- +ments are allowed 𝑓 (𝑥, 𝑦, 𝑧, 𝑣𝑥, 𝑣𝑦, 𝑣𝑧, 𝑇, 𝑇∞, 𝑡) where: +𝑥, 𝑦, 𝑧 = segment centroid coordinates +𝑣𝑥, 𝑣𝑦, 𝑣𝑧 = segment centroid velocity components +𝑇 = segment centroid temperature +𝑇∞ = environment temperature, T∞ +𝑡 = solution time +3. This keyword is supported in the SPH elements to define the flux boundary +conditions for a thermal or coupled thermal/structural analysis. The values 𝑛1, +𝑛2, 𝑛3, 𝑛4 from the SPH particles or segments are used to define the flux seg- +ments. +*BOUNDARY_MCOL +Purpose: Define parameters for MCOL coupling. The MCOL Program is a rigid body +mechanics program for modeling the dynamics of ships. See Remark 1 for more +information. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NMCOL MXSTEP +ETMCOL +TSUBC PRTMCOL +Type +Default +I +2 +I +F +F +F +none +0.0 +0.0 +none +Remarks +2 +Ship Card. Include NMCOL cards, one for each ship. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RBMCOL +MCOLFILE +Type +I +Default +A60 +none + VARIABLE +DESCRIPTION +NMCOL +Number of ships in MCOL coupling. +MXSTEP +Maximum of time step in MCOL calculation. If the number of +MCOL time steps exceeds MXSTEP, then LS-DYNA will +terminate. +ETMCOL +Uncoupling termination time, see Remark 2 below. +EQ.0.0: set to LS-DYNA termination time +TSUBC +Time interval for MCOL subcycling. +EQ.0.0: no subcycling +VARIABLE +DESCRIPTION +PRTMCOL +Time interval for output of MCOL rigid body data. +RBMCOL +LS-DYNA rigid body material assignment for the ship. +MCOLFILE +Filename containing MCOL input parameters for the ship. +Remarks: +1. The basis for MCOL is a convolution integral approach for simulating the +equations of motion. A mass and inertia tensor are required as input for each +ship. The masses are then augmented to include the effects of the mass of the +surrounding water. A separate program determines the various terms of the +damping/buoyancy force formulas which are also input to MCOL. The cou- +pling is accomplished in a simple manner: at each time step LS-DYNA com- +putes the resultant forces and moments on the MCOL rigid bodies and passes +them to MCOL. MCOL then updates the positions of the ships and returns the +new rigid body locations to LS-DYNA. A more detailed theoretical and practi- +cal description of MCOL can be found in a separate report (to appear). +2. After the end of the LS-DYNA/MCOL calculation, the analysis can be pursued +using MCOL alone. ETMCOL is the termination time for this analysis. If +ETMCOL is lower than the LS-DYNA termination time, the uncoupled analysis +will not be activated. +3. The MCOL output is set to the files mcolout (ship position) and mcolenergy +(energy breakdown). In LS-PrePost, mcolout can be plotted through the rigid +body time history option and MCOLENERGY +*BOUNDARY_NON_REFLECTING +Purpose: Define a non-reflecting boundary. This option applies to continuum domains +modeled with solid elements. For geomechanical problems this option is important for +limiting the spatial extent of the finite element mesh and thus the number of solid +elements. +4 +5 +6 +7 +8 + Card 1 +1 +Variable +SSID +Type +I +2 +AD +F +3 +AS +F +Default +none +0.0 +0.0 +Remarks +1, 2 +3 +3 + VARIABLE +DESCRIPTION +SSID +AD +Segment set ID, see *SET_SEGMENT. +Default activation flag for dilatational waves. +EQ.0.0: on +NE.0.0: off +AS +Default activation flag for shear waves. +EQ.0.0: on +NE.0.0: off +Remarks: +1. Non-reflecting boundaries defined with this keyword are only used with three- +dimensional solid elements. Boundaries are defined as a collection of segments, +and segments are equivalent to element faces on the boundary. Segments are +defined by listing the corner nodes in either a clockwise or counterclockwise +order. +2. Non-reflecting boundaries are used on the exterior boundaries of an analysis +model of an infinite domain, such as a half-space to prevent artificial stress +wave reflections generated at the model boundaries form reentering the model +and contaminating the results. Internally, LS-DYNA computes an impedance +matching function for all non-reflecting boundary segments based on an as- +sumption of linear material behavior. Thus, the finite element mesh should be +constructed so that all significant nonlinear behavior is contained within the +discrete analysis model. +3. With the two optional switches, the influence of reflecting waves can be +studied. +4. During the dynamic relaxation phase (optional), nodes on non-reflecting +segments are constrained in the normal direction. Nodal forces associated with +these constraints are then applied as external loads and held constant in the +transient phase while the constraints are replaced with the impedance matching +functions. In this manner, soil can be quasi-statically prestressed during the +dynamic relaxation phase and dynamic loads (with non-reflecting boundaries) +subsequently applied in the transient phase. +5. +In explicit analyses this command has the side effect of reducing the default +value for the time step scale factor from 0.9 to 0.667. A nonzero value of TSS- +FAC in *CONTROL_TIMESTEP will override that default. +*BOUNDARY_NON_REFLECTING_2D +Purpose: Define a non-reflecting boundary. This option applies to continuum domains +modeled with two-dimensional solid elements in the xy plane. For geomechanical +problems, this option is important for limiting the size of the models. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NSID +Type +I +Default +none +Remarks +1, 2 + VARIABLE +DESCRIPTION +NSID +Node set ID, see *SET_NODE. See Figure 5-2. +Remarks: +1. Non-reflecting boundaries defined with this keyword are only used with two- +dimensional solid elements in either plane strain or axisymmetric geometries. +Boundaries are defined as a sequential string of nodes moving counterclock- +wise around the boundary. +2. Non-reflecting boundaries are used on the exterior boundaries of an analysis +model of an infinite domain, such as a half-space to prevent artificial stress +wave reflections generated at the model boundaries from reentering the model +and contaminating the results. Internally, LS-DYNA computes an impedance +matching function for all non-reflecting boundary segments based on an as- +sumption of linear material behavior. Thus, the finite element mesh should be +constructed so that all significant nonlinear behavior in contained within the +discrete analysis model. +Define the nodes k, k+1, k+2, ..., +k+n while moving counterclockwise +around the boundary. +k+2 +k+1 +k+n +Figure 5-2. When defining a transmitting boundary in 2D define the node +numbers in the node set in consecutive order while moving counterclockwise +around the boundary. +*BOUNDARY_PAP +Purpose: Define pressure boundary conditions for pore air flow calculation, e.g. at +structure surface exposed to atmospheric pressure. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SEGID +LCID +CMULT +CVMASS +BLOCK +TBIRTH +TDEATH +CVRPER +Type +I +F +F +F +F +Default +none +none +none +none +0.0 +0.0 +1.e20 +1.0 +Remark +1, 2 +3 + VARIABLE +DESCRIPTION +SEGID +Segment set ID +LCID +Load curve giving pore air pressure vs. time. +EQ.0: constant pressure assumed equal to CMULT +CMULT +Factor on curve or constant pressure head if LCID = 0 +CVMASS +Initial mass of a control volume next to the segment set SETID +BLOCK +Contact blockage effect, +EQ.0: When all segments in SEGID are subject to the pressure +defined by LCID and CMULT; +EQ.1: When only elements in SEGID not involved in contact +are subject to the pressure defined by LCID and CMULT. +TBIRTH +Time at which boundary condition becomes active +TDEATH +Time at which boundary condition becomes inactive +CVRPER +Permeability factor of cover material, where cover refers to a shell +layer coating the surface of the solid. Default value is 1.0 when it +is not defined. See Remark 3 below. +0.0 ≤ CVRPER ≤ 1.0 +Control Volume +SEGID +Segment ID for the part +of the boundary through +which air flows to and from +the control volume. +Sample +Figure 5-3. Air flows between the control volume and the sample. CVMASS +specifies the control volume’s initial mass, and CVMULT sets the initial +pressure. +Remarks: +1. All structure surfaces subject to specified pressure have to be defined. +2. A non-zero CVMASS, together with a non-zero CMULT and an un-defined +LCID, can be used to simulate air mass transfer between a control volume and a +test specimen containing pore air. The control volume is assumed to have a +fixed volume, and have initial pressure of CMULT and initial mass of +CVMASS. Air mass transfer happens between control volume and its neighbor- +ing specimen. Such mass transfer results in pressure change in control volume +and test specimen. +3. CVRPER allows users to model the porosity properties of the cover material. If +SEGID is covered by a material of very low permeability (e.g., coated fabric), it +is appropriate to set CVRPER = 0. In this case, Pc, the pressure calculated as- +suming no boundary condition, is applied to SEGID. If SEGID is not covered +by any material, it is appropriate to set CVRPER = 1, the default value. In this +case, the applied pressure becomes Pb, the boundary pressure determined by +CMULT and LCID. +*BOUNDARY_PORE_FLUID_OPTION +Available options include: +PART +SET +Purpose: Define parts that contain pore fluid. Defaults are given on *CONTROL_- +PORE_FLUID. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +P(S)ID WTABLE +PF_RHO +ATYPE +PF_BULK +ACURVE WTCUR +SUCLIM +Type +I +Default +none +F +* +F +* +I +* +F +* +I +0 +I +0 +F +0. +* Defaults are taken from *CONTROL_PORE_FLUID + VARIABLE +PID, PSID +DESCRIPTION +Part ID (PID) or Part set ID, see *PART and *SET_PART. All +elements within the part must lie below the water table. +WTABLE +Z-coordinate at which pore pressure = 0 (water table) +PF_RHO +Density of pore water in soil skeleton: +EQ.0: Default density specified on *CONTROL_PORE_FLUID +card is used. +ATYPE +Analysis type for Parts: +EQ.0: Default to value specified on *CONTROL_PORE_FLUID +EQ.1: Undrained analysis +EQ.2: Drained analysis +EQ.3: Time dependent consolidation (coupled) +EQ.4: Consolidate to steady state (uncoupled) +EQ.5: Drained in dynamic relaxation, undrained in transient +VARIABLE +DESCRIPTION +PF_BULK +Bulk modulus of pore fluid: +EQ.0: Default to value specified on *CONTROL_PORE_FLUID +ACURVE +Curve of analysis type vs time +WTCUR +Curve of water table (z-coordinate) vs time +SUCLIM +Suction limit (defined in head, i.e. length units). Must not be +negative. See remarks. +Remarks: +This card must be present for all parts having pore water. +The density on this card is used only to calculate pressure head. To ensure the correct +gravity loading, the density of the soil material should be increased to include the mass +associated with the pore water. +The y-axis values of the curve of analysis type vs time can only be 1, 2 or 3. During +dynamic relaxation, the analysis type will be taken from the first value on the curve +The default for SUCLIM is zero, meaning that the pore fluid cannot generate suction. +To allow unlimited suction, set this parameter to a large positive number. +*BOUNDARY_PRECRACK +Purpose: Define pre-cracks in XFEM shell formulations 52 or 54 for purposes of fracture +analysis. +4 +5 +6 +7 +8 + Card 1 +1 +2 +Variable +PID +CTYPE +Type +I +Default +I +1 +3 +NP +I +Precrack Point Cards. Include NP cards, one for each point in the pre-crack. +4 +5 +6 +7 +8 +1 +X +F +2 +Y +F +3 +Z +F + Card 2 +Variable +Type +Default + VARIABLE +DESCRIPTION +PID +Part ID where the pre-crack is located +CTYPE +Type of pre-crack: +EQ.1: straight line +NP +Number of points defining the pre-crack +X, Y, Z +Coordinates of the points defining the pre-crack +*BOUNDARY_PRESCRIBED_ACCELEROMETER_RIGID +Purpose: Prescribe the motion of a rigid body based on experimental data obtained +from accelerometers affixed to the rigid body. +Note: This feature is available starting with LS-DYNA 971R3. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID +SOLV +Type +I +Default +none +I +1 +Accelerometer Cards. Define one card for each accelerometer affixed to the rigid +body. Input is terminated when a “*” card is found. A minimum of three +accelerometers are required . + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NID +CID +LCIDX +LCIDY +LCIDZ +Type +I +I +I +I +I +Default +none +none +none +none +none + VARIABLE +DESCRIPTION +PID +Part ID for rigid body whose motion is prescribed. +SOLV +Solver type: +EQ.1: Gaussian elimination (default), +EQ.2: linear regression +NID +CID +Node ID corresponding to the location of the accelerometer. +the +Coordinate system +accelerometer’s +*DEFINE_COORDINATE_- +NODES). All nodes must reside on the same part. Set FLAG = 1. +the orientation of +ID describing +local axes +(see +VARIABLE +DESCRIPTION +Load curve ID containing the local x-acceleration time history +from the accelerometer. +Load curve ID containing the local y-acceleration time history +from the accelerometer. +Load curve ID containing the local z-acceleration time history +from the accelerometer. +LCIDX +LCIDY +LCIDZ +Remarks: +1. Acceleration time histories from a minimum of three accelerometers each +providing output from three channels are required. Load curves must have the +same number of points and data must be uniformly spaced. +2. Local axes of the accelerometers must be orthogonal. +*BOUNDARY_PRESCRIBED_FINAL_GEOMETRY +The final displaced geometry for a subset of nodal points is defined. The nodes of this +subset are displaced from their initial positions specified in the *NODE input to the +final geometry along a straight line trajectory. A load curve defines a scale factor as a +function of time that is bounded between zero and unity corresponding to the initial +and final geometry, respectively. A unique load curve can be specified for each node, +or a default load curve can apply to all nodes. The external work generated by the +displacement field is included in the energy ratio calculation for the glstat file. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +BPFGID +LCIDF +DEATHD +Type +Default +I +0 +I +0 +F +infinity +Node Cards. The next “*” keyword card terminates this input. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +Variable +NID +Type +I +X +F +Default +none +0. +Y +F +0. +Z +F +0. +LCID +DEATH +I +F +LCIDF +infinity + VARIABLE +DESCRIPTION +BPFGID +ID for this set of imposed boundary conditions +LCIDF +Default load curve ID. This curve varies between zero and unity. +DEATHD +Default death time. At this time the prescribed motion is inactive +and the nodal point is allowed to move freely. +NID +Node ID for which the final position is defined. Nodes defined in +this section must also appear under the *NODE input. +X +x-coordinate of final geometry +VARIABLE +DESCRIPTION +Y +Z +y-coordinate of final geometry +z-coordinate of final geometry +LCID +Load curve ID. If zero the default curve ID, LCIDF, is used. +DEATH +Death time. If zero the default value, DEATHD, is used. +*BOUNDARY_PRESCRIBED_MOTION_OPTION1_{OPTION2} +Available options for OPTION1 include: +NODE +SET +SET_BOX +SET_SEGMENT +RIGID +RIGID_LOCAL +SET_LINE +OPTION2 allows an optional ID to be given that applies either to the single node, node +set or a rigid body. +ID +If a heading is defined with the ID, then the ID with the heading will be written at the +beginning of the ASCII file, bndout. +Purpose: Define an imposed nodal motion (velocity, acceleration, or displacement) on a +node or a set of nodes. Also velocities and displacements can be imposed on rigid +bodies. If the local option is active the motion is prescribed with respect to the local +coordinate system for the rigid body . +Translational nodal velocity and acceleration specifications for rigid body nodes are +allowed and are applied as described at the end of this section. For nodes on rigid +bodies use the NODE option. Do not use the NODE option in r-adaptive problems +since the node ID's may change during the adaptive step. +The SET_LINE option allows a node set to be generated including existing nodes and +new nodes created from h-adaptive mesh refinement along the straight line connecting +two specified nodes to be included in prescribed boundary conditions. +HEADING +A70 +5 +SF +F +*BOUNDARY +*BOUNDARY_PRESCRIBED_MOTION +ID Card. Additional card for ID keyword option. +2 +3 +4 +5 +6 +7 +8 +ID +Variable +1 +ID +Type +I + Card 1 +1 +2 +3 +4 +Variable +typeID +DOF +VAD +LCID +Type +I +I +Default +none +none +I +0 +I +none +1. +6 +7 +8 +VID +DEATH +BIRTH +I +0 +F +F +1028 +0.0 +For the SET_BOX keyword option, define the following additional card. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +BOXID +TOFFSET LCBCHK +Type +I +Default +none +I +0 +I +0 +Additional card that is expected if DOF = 9, 10, 11 or VAD = 4 on the first card; +otherwise skip this card. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable OFFSET1 OFFSET2 +MRB +NODE1 +NODE2 +Type +F +Default +0. +F +0. +I +0 +I +0 +I +For the SET_LINE keyword option, define the following additional card. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NBEG +NEND +Type +I +I +Default +none +none + VARIABLE +DESCRIPTION +ID +Optional PRESCRIBED MOTION set ID to which this node, node +set, segment set or rigid body belongs. This ID does not need to +be unique. +HEADING +An optional descriptor for the given ID that will be written into +the d3hsp file and the bndout file. +typeID +Node ID (NID in *NODE), nodal set ID (SID in *SET_NODE), +segment set ID (SID in *SET_SEGMENT, see DOF = 12) or part ID +(PID in *PART) for a rigid body. +DOF +Applicable degrees-of-freedom: +EQ.1: +EQ.2: +EQ.3: +EQ.4: +EQ.-4: +EQ.5: +EQ.6: +EQ.7: +EQ.8: +𝑥-translational degree-of-freedom, +𝑦-translational degree-of-freedom, +𝑧-translational degree-of-freedom, +translational motion in direction given by the VID. +Movement on plane normal to the vector is permitted. +translational motion in direction given by the VID. +Movement on plane normal to the vector is not permit- +ted. This option does not apply to rigid bodies. +𝑥-rotational degree-of-freedom, +𝑦-rotational degree-of-freedom, +𝑧-rotational degree-of-freedom, +rotational motion about a vector parallel to vector VID. +Rotation about the normal axes is permitted. +EQ.-8: rotational motion about a vector parallel to vector VID. +Rotation about the normal axes is not permitted. This +VARIABLE +DESCRIPTION +option does not apply to rigid bodies. +EQ.9: +𝑦/𝑧 degrees-of-freedom for node rotating about the 𝑥- +axis at location (OFFSET1, OFFSET2) in the 𝑦𝑧-plane, +point (𝑦, 𝑧). Radial motion is NOT permitted. Not ap- +plicable to rigid bodies. +EQ.-9: 𝑦/𝑧 degrees-of-freedom for node rotating about the 𝑥- +axis at location (OFFSET1, OFFSET2) in the 𝑦𝑧-plane, +point (𝑦, 𝑧). Radial motion is permitted. Not applica- +ble to rigid bodies. +EQ.10: 𝑧/𝑥 degrees-of-freedom for node rotating about the 𝑦- +axis at location (OFFSET1, OFFSET2) in the 𝑧𝑥-plane, +point (𝑧, 𝑥). Radial motion is NOT permitted. Not ap- +plicable to rigid bodies. +EQ.-10: 𝑧/𝑥 degrees-of-freedom for node rotating about the 𝑦- +axis at location (OFFSET1, OFFSET2) in the 𝑧𝑥-plane, +point (𝑧, 𝑥). Radial motion is permitted. Not applica- +ble to rigid bodies. +EQ.11: 𝑥/𝑦 degrees-of-freedom for node rotating about the z- +axis at location (OFFSET1, OFFSET2) in the 𝑥𝑦-plane, +point (𝑥, 𝑦). Radial motion is NOT permitted. Not ap- +plicable to rigid bodies. +EQ.-11: 𝑥/𝑦 degrees-of-freedom for node rotating about the 𝑧- +axis at location (OFFSET1, OFFSET2) in the 𝑥𝑦-plane, +point (𝑥, 𝑦). Radial motion is permitted. Not applica- +ble to rigid bodies. +EQ.12: translational motion in direction given by the normals +to the segments defined by the set typeID. +VAD +Velocity/Acceleration/Displacement flag: +EQ.0: velocity (rigid bodies and nodes), +EQ.1: acceleration (rigid bodies and nodes), +EQ.2: displacement (rigid bodies and nodes). +EQ.3: velocity versus displacement (rigid bodies only) +EQ.4: relative displacement (rigid bodies only) +VARIABLE +LCID +DESCRIPTION +Curve ID or function ID to describe motion value versus time, see +*DEFINE_CURVE, +*DE- +FINE_FUNCTION. If LCID refers to *DEFINE_FUNCTION, the +function can have only time as an argument, e.g., 𝑓 (𝑡) = 10.0 × 𝑡. +See BIRTH below. +*DEFINE_CURVE_FUNCTION, or +SF +VID +Load curve scale factor. (default = 1.0) +Vector ID for DOF values of 4 or 8, see *DEFINE_VECTOR. The +direction of this vector is not updated with time. +DEATH +Time imposed motion/constraint is removed: +EQ.0.0: default set to 1028 +BIRTH +BOXID +LCBCHK +Time that the imposed motion/constraint is activated. The +prescribed motion begins acting at time = BIRTH but from the +zero abscissa value of the curve or function (*DEFINE_FUNC- +TION). In other words, the abscissae are shifted by an amount +BIRTH, i.e., it has the same effect as setting OFFA = BIRTH in +*DEFINE_CURVE. Warning: BIRTH is ignored if the LCID is +defined as a function, i.e., *DEFINE_CURVE_FUNCTION. +A box ID defining a box region in space in which the constraint is +activated. Only the nodes falling inside the box will be applied +the prescribed motion. If LCBCHK is not defined, the box +volume is reevaluated every time step to determine the nodes for +which the prescribed motion is active. This reevaluation of the +volume is referred to as a “box-check”. +Optional load curve allowing more flexible and efficient use of +SET_BOX option. Instead of performing box-check at every time +step, discrete box-check times could be given as 𝑥-values of +LCBCHK. LCBCHK’s 𝑦-values specify corresponding death +times. For example, a curve with points (20, 30) and (50, 70) will +result in two box checks. The first will occur at 20, and the +prescribed motion will be active from 20 to 30. The second will +occur at 50, and the prescribed motion will be active from 50 to +70. A 𝑦-value of “0” means the prescribed motion will stay active +until next box-check. For example, an additional 3rd point of (90, +0) will lead to another box-check at 90, and the prescribed motion +will be active from 90 until the end of the simulation. +VARIABLE +DESCRIPTION +TOFFSET +Time offset flag for the SET_BOX option: +EQ.1: the time value of the load curve, LCID, will be offset by +the time when the node enters the box, +EQ.0: no time offset is applied to LCID +OFFSET1 +Offset for DOF types 9-11 (𝑦, 𝑧, 𝑥 direction) +OFFSET2 +Offset for DOF types 9-11 (𝑧, 𝑥, 𝑦 direction) +MRB +Master rigid body for measuring the relative displacement. +NODE1 +Optional orientation node, n1, for relative displacement +NODE2 +Optional orientation node, n2, for relative displacement +Node ID of a starting node. +Node ID of an ending node. All existing nodes and new nodes +generated by h-adaptive mesh refinement along the straight line +connecting NBEG and NEND will be included in the prescribed +boundary motions. +NBEG +NEND +Remarks: +When DOF = 5, 6, 7, or 8, nodal rotational degrees-of-freedom are prescribed in the case +of deformable nodes (OPTION1 = NODE or SET) whereas body rotations are prescribed +in the case of a rigid body (OPTION1 = RIGID). In the case of a rigid body, the axis of +prescribed rotation always passes through the body's center of mass. For |DOF| = 8, +the axis of the prescribed rotation is parallel to vector VID. To prescribe a body rotation +of a set of deformable nodes, with the axis of rotation parallel to global axes 𝑥, 𝑦, or 𝑧, +use OPTION1 = SET with |DOF| = 9, 10, or 11, respectively. The load curve scale +factor can be used for simple modifications or unit adjustments. +The relative displacement can be measured in either of two ways: +1. Along a straight line between the mass centers of the rigid bodies, +2. Along a vector beginning at node 𝑛1 and terminating at node 𝑛2. +With option 1, a positive displacement will move the rigid bodies further apart, and, +likewise a negative motion will move the rigid bodies closer together. The mass centers +of the rigid bodies must not be coincident when this option is used. With option 2 the +relative displacement is measured along the vector, and the rigid bodies may be +coincident. Note that the motion of the master rigid body is not directly affected by this +option, i.e., no forces are generated on the master rigid body. +The activation time, BIRTH, is the time during the solution that the constraint begins to +act. Until this time, the prescribed motion card is ignored. The function value of the +load curves will be evaluated at the offset time given by the difference of the solution +time and BIRTH, i.e., (solution time-BIRTH). Relative displacements that occur prior to +reaching BIRTH are ignored. Only relative displacements that occur after BIRTH are +prescribed. +When the constrained node is on a rigid body, the translational motion is imposed +without altering the angular velocity of the rigid body by calculating the appropriate +translational velocity for the center of mass of the rigid body using the equation: +𝐯cm = 𝐯node − 𝛚 × (𝐱cm − 𝐱node) +where 𝐯𝑐𝑚 is the velocity of the center of mass, 𝐯node is the specified nodal velocity, 𝛚 is +the angular velocity of the rigid body, 𝐱cm is the current coordinate of the mass center, +and 𝐱node is the current coordinate of the nodal point. Extreme care must be used when +prescribing motion of a rigid body node. Typically, for nodes on a given rigid body, the +motion of no more than one node should be prescribed or unexpected results may be +obtained. +When the RIGID option is used to prescribe rotation of a rigid body, the axis of rotation +will always be shifted such that it passes through the center-of-mass of the rigid body. +By using *PART_INERTIA or *CONSTRAINED_NODAL_RIGID_BODY_INERTIA, one +can override the internally-calculated location of the center-of-mass. +When the RIGID_LOCAL option is invoked, the orientation of the local coordinate +system rotates with time in accordance with rotation of the rigid body. +Angular displacements are applied in an incremental fashion hence it is not possible to +correctly prescribe a successive set of rotations about multiple axes. In light of this the +command *BOUNDARY_PRESCRIBED_ORIENTATION_RIGID should be used for the +purpose of prescribing the general orientation of a rigid body. +Example: +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *BOUNDARY_PRESCRIBED_MOTION_SET +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ A set of nodes is given a prescribed translational velocity in the +$ x-direction according to a specified vel-time curve (which is scaled). +$ +*BOUNDARY_PRESCRIBED_MOTION_SET +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ nsid dof vad lcid sf vid death + 4 1 0 8 2.0 +$ +$ nsid = 4 nodal set ID number, requires a *SET_NODE_option +$ dof = 1 motion is in x-translation +$ vad = 0 motion prescribed is velocity +$ lcid = 8 velocity follows load curve 8, requires a *DEFINE_CURVE +$ sf = 2.0 velocity specified by load curve is scaled by 2.0 +$ vid not used in this example +$ death use default (essentially no death time for the motion) +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *BOUNDARY_PRESCRIBED_MOTION_RIGID +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ A rigid body is given a prescribed rotational displacement about the +$ z-axis according to a specified displacement-time curve. +$ +*BOUNDARY_PRESCRIBED_MOTION_RIGID +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ pid dof vad lcid sf vid death + 84 7 2 9 14.0 +$ +$ pid = 84 apply motion to part number 84 +$ dof = 7 rotation is prescribed about the z-axis +$ vad = 2 the prescribed motion is displacement (angular) +$ lcid = 9 rotation follows load curve 9, requires a *DEFINE_CURVE +$ (rotation should be in radians) +$ sf use default (sf = 1.0) +$ vid not used in this example +$ death = 14 prescribed motion is removed at 14 ms (assuming time is in ms) +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +SET_LINE option: +Referring to Figure 5-4 and a partial keyword example below, a flat plate is being pulled +along one edge while the opposite edge is fully constrained. All four existing nodes +and new nodes created from h-adaptive mesh refinement along the straight line +connecting nodes 98 and 105 will be included in a node set ID 122, which is subjected to +a velocity boundary condition defined by load curve ID 2. From the deformed shape, it +is evident all nodes are pulled equally according to the boundary condition. +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +*BOUNDARY_PRESCRIBED_MOTION_SET_LINE +$# nsid dof vad lcid sf vid death birth + 122 3 0 2 +$ NBEG NEND + 98 105 +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +*DEFINE_CURVE +0.0 &velo + &endtime &velo + 1000.0 &velo +Revision Information: +SET_LINE option is available starting in Revision 109996 for both SMP and MPP. +All nodes fixed +along this edge +Undeformed mesh +X Y +Node 98 +Node 105 +All existing nodes along the +straight line connecting nodes 98 +and 105 are automatically included +in the displacement boundary. +A displacement boundary condition +Node 105 +Deformed mesh +Node 98 +New nodes created from +adaptive refinement along the +straight line connecting nodes +98 and 105 are also included +in the displacement boundary. +Figure 5-4. The SET_LINE option usage. +*BOUNDARY_PRESCRIBED_ORIENTATION_RIGID_OPTION1_{OPTION2} +Available options OPTION1 include: +DIRCOS +ANGLES +EULERP +VECTOR +OPTION2 allows an optional ID: +ID +The defined ID can be referred to by *SENSOR_CONTROL. +Purpose: Prescribe the orientation of rigid body as a function of time. +Card Formats: +ID Card. Optional card for ID keyword option. +ID +Variable +1 +ID +Type +I +2 +3 +4 +5 +6 +7 +8 +HEADING +A70 +Card 1 is common to all orientation methods. +Cards 2 to 3 are unique for each orientation method. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PIDB +PIDA +INTRP +BIRTH +DEATH +TOFFSET +Type +I +Default +none +I +0 +I +1 +F +0. +F +1020 +I +VARIABLE +ID +DESCRIPTION +Optional ID for PRESCRIBED ORIENTATION that can be +referred to by *SENSOR_CONTROL. When not defined, the +sequential definition order will be used as ID when referred to by +*SENSOR_CONTROL. +HEADING +An optional descriptor for the given ID. +PIDA +Part ID for rigid body A. If zero then orientation of PIDB is +performed with respect to the global reference frame. +INTRP +Interpolation method used on time history curves: +EQ.1: linear interpolation (default) +EQ.2: cubic spline +development) +interpolation +(experimental – under +BIRTH +DEATH +Prior to this time the body moves freely under the action of other +agents. +The body is freed at this time and subsequently allowed to move +under the action of other agents. +TOFFSET +Time offset flag: +EQ.1: The time value of all load curves will be offset by the +birth time. +EQ.0: No time offset is applied. +Cosine Card 1. Additional card for DIRCOS option. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCIDC11 LCIDC12 LCIDC13 LCIDC21 LCIDC22 LCIDC23 LCIDC31 LCIDC32 +Type +I +I +I +I +I +I +I +I +Default +none +none +none +none +none +none +none +none +Cosine Card 2. Additional card for DIRCOS option. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCIDC33 +Type +I +Default +none + VARIABLE +LCIDCij +DESCRIPTION +Load curve ID specifying direction cosine 𝐶𝑖𝑗 as a function of +time. 𝐶𝑖𝑗 is defined as: +𝐶𝑖𝑗 = 𝐚𝑖 ⋅ 𝐛𝑗 +where the {𝒂𝑖} are mutually perpendicular unit vectors fixed in +PIDA and the {𝒃𝑗} are mutually perpendicular unit vectors fixed +in PIDB. If PIDA = 0 then the {𝒂𝑖} are unit vectors aligned with +the global 𝑥, 𝑦, and 𝑧. See Remark 1. +Angles Card. Additional card for ANGLES option. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCIDQ1 +LCIDQ2 +LCIDQ3 +ISEQ +ISHFT +BODY +Type +I +I +I +I +Default +none +none +none +none +I +1 +I +0 + VARIABLE +LCIDQi +ISEQ +DESCRIPTION +Load curve ID specifying the orientation angle 𝑞𝑖 in radians as a +function of time. See Remark 1. +Specifies the sequence in which the rotations are performed. In this +first set of sequences three unique axes are involved. This sequence +is associated with what are commonly called Cardan or Tait-Bryan +angles. All angles are in units of radians. Whether these rotations are +intrinsic or extrinsic is determined by the BODY field. +EQ.123: The first rotation is performed about the 𝑥 axis through +an angle of 𝑞1, the second about the 𝑦 axis through an +angle of 𝑞2, and the third about the 𝑧 axis through an +angle of 𝑞3. +EQ.231: The first rotation is performed about the 𝑦 axis through +an angle of 𝑞1, the second about the 𝑧 axis through an +angle of 𝑞2, and the third about the 𝑥 axis through an +angle of 𝑞3. +EQ.312: The first rotation is performed about the 𝑧 axis through +an angle of 𝑞1, the second about the 𝑥 axis through an +angle of 𝑞2, and the third about the 𝑦 axis through an +angle of 𝑞3. +EQ.132: The first rotation is performed about the 𝑥 axis through +an angle of 𝑞1, the second about the 𝑧 axis through an +angle of 𝑞2, and the third about the 𝑦 axis through an +angle of 𝑞3. +EQ.213: The first rotation is performed about the 𝑦 axis through +an angle of 𝑞1, the second about the 𝑥 axis through an +angle of 𝑞2, and the third about the 𝑧 axis through an +angle of 𝑞3. +EQ.321: The first rotation is performed about the 𝑧 axis through +an angle of 𝑞1, the second about the 𝑦 axis through an +angle of 𝑞2, and the third about the 𝑧 axis through an +angle of 𝑞3. +The second set of sequences involve only two unique axes where +the first and third are repeated. This sequence is associated with +what are commonly called Euler angles. +EQ.121: the first rotation is performed about the 𝑥 axis through +an angle of 𝑞1, the second about the 𝑦 axis through an +angle of 𝑞2, and the third about the 𝑥 axis through an +angle of 𝑞3. +EQ.131: The first rotation is performed about the 𝑥 axis through +an angle of 𝑞1, the second about the 𝑧 axis through an +angle of 𝑞2, and the third about the 𝑥 axis through an +angle of 𝑞3. +EQ.212: The first rotation is performed about the 𝑦 axis through +an angle of 𝑞1, the second about the 𝑥 axis through an +angle of 𝑞2, and the third about the 𝑦 axis through an +angle of 𝑞3. +EQ.232: The first rotation is performed about the 𝑦 axis through +an angle of 𝑞1, the second about the 𝑧 axis through an +angle of 𝑞2, and the third about the 𝑦 axis through an +angle of 𝑞3. +EQ.313: The first rotation is performed about the 𝑧 axis through +an angle of 𝑞1, the second about the 𝑥 axis through an +angle of 𝑞2, and the third about the 𝑧 axis through an +angle of 𝑞3. +EQ.323: The first rotation is performed about the 𝑧 axis through +an angle of 𝑞1, the second about the 𝑦 axis through an +angle of 𝑞2, and the third about the 𝑧 axis through an +angle of 𝑞3. +ISHFT +Angle shift. +EQ.1: Angle curves are unaltered. +EQ.2: Shifts angle data in the LCIDQi curves as necessary to +eliminate discontinuities. If angles are confined to the +range [−𝜋, 𝜋] and the data contains excursions exceeding +𝜋 then set ISHFT = 2. +BODY +Reference axes. +EQ.0: Rotations are performed about axes fixed in PIDA +(extrinsic rotation, default). +EQ.1: Rotations are performed about axes fixed in PIDB (intrinsic +rotation). +Euler Parameter Card. Additional card for EULERP option. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCIDE1 +LCIDE2 +LCIDE3 +LCIDE4 +Type +I +I +I +I +Default +none +none +none +none +VARIABLE +LCIDEi +DESCRIPTION +Load curve ID specifying Euler parameter 𝑒𝑖 as a function of time. +The Euler parameters are defined as follows. See Remark 1. +𝜀𝑖 = 𝜺 ⋅ 𝒂𝑖 = 𝜺 ⋅ 𝒃𝑖, +(𝑖 = 1, 2, 3) +𝜀4 = cos ( +) +where 𝜺 is the Euler vector, {𝒂𝑖} and {𝒃𝑖} are dextral sets of unit +vectors fixed in PIDA and PIDB, respectively, and 𝜃 (in radians) is +associated with the rotation of PIDB in PIDA about Euler vector. +If PIDA = 0 then the {𝒂𝑖} are unit vectors aligned, respectively, +with the global 𝑥, 𝑦, and 𝑧 axes. +2)𝒏 and 𝜀4 = cos(𝜃 +The Euler parameters are defined as 𝜺 = sin(𝜃 +2), respectively. Here 𝒏 +is a unit vector defining the axis of rotation, and 𝜃 is the angle with which the rotation +2 = +occurs, and consequently the four parameters are subjected to the condition 𝛆𝑇𝛆 + 𝜀4 +1. It is therefore recommended that the control points of the curves already fulfil this or +else LS-DYNA will internally normalize these values. From the Euler parameters at +time 𝑡, a unique rotation matrix 𝑸𝑡 is computed that is used to determine the total +orientation 𝑸. The rotation is performed with respect to the reference state 𝑸0 given by +the Euler parameters at time 0. In general, 𝑸0 ≠ 𝑰 and the rotation of the rigid body is +𝑇. If the parameters are initially 𝜺 = 𝟎 and 𝜀4 = 1, then the reference +given by 𝑸 = 𝑸𝑡𝑸0 +state is 𝑸0 = 𝑰 and 𝑸 = 𝑸𝑡 defines the orientation of the rigid body. +For a nonzero PIDA, the rotation matrix 𝑸 as defined above is expressed in a system +that is fixed in rigid body A. If this system is denoted 𝑹𝑡 at time 𝑡, and assuming 𝑹0 = +𝑰, the orientation with respect to a global system is 𝑹𝑸. +Vector Card. Additional card for VECTOR option. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCIDV1 +LCIDV2 +LCIDV3 +LCIDS +VALSPIN +Type +I +I +I +Default +none +none +none +I +0 +F +0. +VARIABLE +LCIDVi +DESCRIPTION +Load curve ID specifying the vector measure number 𝑣𝑖 as a +function of time. The vector measure numbers are defined as +follows. See Remark 1. +𝑣𝑖 = 𝒗 ⋅ 𝒏𝑖, +𝑖 = 1, 2, 3. +where 𝒗 is a vector and {𝒏𝑖} are unit vectors aligned, respectively, +with the global axes 𝑥, 𝑦, and 𝑧 axes. Note that the vector 𝒗 is +attached to the body in question, so changing the direction of this +vector will induce a rotation of the body defined by 𝝋̇ = 𝒗 × 𝒗̇. +LCIDS +Load curve ID which specifies the overlayed spin speed 𝜃̇ of +PIDB about the axis parallel to the vector 𝒗. +EQ.0: a constant spin speed as defined by VALSPIN is used, +GT.0: Load curve for spin speed (radians per unit time). +VALSPIN +Value for the constant spin speed of PIDB (radians per unit time +𝜃̇). This option is bypassed if the load curve number defined +above is non-zero. +𝜃̇ +𝑛 +𝒗𝑛 +Time 𝑡𝑛 +𝜃̇ +𝑛+1 +𝒗𝑛+1 +Time 𝑡𝑛+1 +Total spin 𝝎 given by +𝝎 = 𝝋̇ + 𝜽̇ = 𝒗 × 𝒗̇ + 𝜃̇𝒗 +Remarks: +1. All load curves must contain the same number of points and the data must be +uniformly spaced. +2. LC0 in *MAT_RIGID must be used to identify a coordinate system for each +rigid body. The coordinate system must be defined with *DEFINE_COORDI- +NATE_NODES and FLAG = 1. Nodes used in defining the coordinate system +must reside on the same body. +3. This feature is incompatible with *DEFINE_CURVE_FUNCTION. +*BOUNDARY_PRESSURE_OUTFLOW_OPTION +Available options include: +SEGMENT +SET +Purpose: Define pressure outflow boundary conditions. These boundary conditions +are attached to solid elements using the Eulerian ambient formulation (refer to +ELFORM in *SECTION_SOLID_ALE) and defined to be pressure outflow ambient +elements (refer to AET in *SECTION_SOLID_ALE). +Card 1 for SET option. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SSID +Type +I +Default +none +Card 1 for SEGMENT option. + Card 1 +Variable +1 +N1 +Type +I +2 +N2 +I +3 +N3 +I +4 +N4 +I +Default +none +none +none +none +5 +6 +7 +8 + VARIABLE +DESCRIPTION +SSID +Segment set ID +N1, N2, … +Node ID’s defining segment +*BOUNDARY_PWP_OPTION +Available options include: +NODE +SET +TABLE +TABLE_SET +Purpose: Define pressure boundary conditions for pore water, e.g. at soil surface. The +TABLE option applies to a whole Part, while the other options apply to specified nodes. + Card 1 +1 +Variable +typeID +Type +I +2 +LC +F +3 +4 +5 +6 +7 +8 +CMULT +LCDR +TBIRTH +TDEATH +F +I +F +F +Default +none +none +0.0 +none +0.0 +1020 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IPHRE +ITOTEX +IDRFLAG +TABLE +Type +Default +I +0 +I +0 +I +0 +I +0 + VARIABLE +DESCRIPTION +typeID +LC +Node ID (option = NODE) or Node set ID (option = SET) or Part +ID (option = TABLE) or Part Set ID (option = TABLE_SET) +Load curve or function giving pore water pressure head (length +units) vs time. +EQ.0: constant pressure head assumed equal to CMULT +(leave blank for TABLE option) +VARIABLE +DESCRIPTION +CMULT +Factor on curve or constant pressure head if LC = 0 +LCDR +Load curve or function giving pore water pressure head during +dynamic relaxation. +EQ.0: during dynamic relaxation, use first pressure head value +on LC +(leave blank for TABLE option) +TBIRTH +Time at which boundary condition becomes active +TDEATH +Time at which boundary condition becomes inactive +IPHRE +EQ.0: default behavior +EQ.1: for phreatic behavior (water can be removed by the +boundary condition but not added, e.g. at a sloping free +surface). Not applicable to TABLE option. See remarks. +ITOTEX +Flag for type of pressure boundary condition: +EQ.0: Total head +EQ.1: Excess head +EQ.2: Hydraulic head +EQ.4: 𝑧-coord where head = 0 (piezometric level) +IDRFLAG +Active flag: +EQ.0: Active only in transient analysis +EQ.1: Active only in dynamic relaxation +EQ.2: Active in all analysis phases +(leave blank for TABLE option) +TABLE +Table ID for TABLE option only. See notes below. +Remarks: +1. Pressure is given as pressure head, i.e. pressure/ρg. +2. NODE and SET options do not affect the pore pressure in Drained parts (the +pore pressure for these is set on a part basis and overrides any nodal boundary +conditions). The TABLE option should be used only with Drained parts. +3. +4. +*BOUNDARY_PWP_NODE or SET overrides pressure head from *BOUND- +ARY_PWP_TABLE at nodes where both are present. +4. If LC is a *DEFINE_FUNCTION, the input arguments are (time, x, y, z, x0, +y0, z0) where x, y and z are the current coordinates and x0, y0, z0 are the initial +coordinates of the node. +TABLE and TABLE_SET options: +The table consists of a list of times in ascending order, followed immediately by curves +of 𝑧-coordinate versus pore pressure head. Each curve represents the pore water +pressure head distribution with 𝑧-coordinate at the corresponding time. There must be +the same number of curves as time values, arranged immediately after the *DEFINE_- +TABLE and in the correct order to correspond to the time values. Each curve should be +arranged in ascending order of 𝑧-coordinate – they look upside-down on the page. The +𝑧-coordinate is the 𝑥-axis of the curve, the pore water pressure head (in length units) is +the y-axis. Each curve should have the same 𝑧-coordinates (𝑥-values) and use the same +value of LCINT. Ensure that the range of 𝑧-coordinates in the curve exceeds by at least +5% the range of 𝑧-coordinates of the nodes belonging to the parts to which the boundary +condition is applied. +IPHRE: +“Phreatic” means that water can be removed by the boundary condition but not added. +The boundary condition enforces that the pressure head be less than or equal to the +stated value. This condition occurs when the free surface of the soil is sloping so that +any water emerging from the soil runs away down the slope. +ITOTEX = 0: +The value from curve or table is total head. This may be used with any pore pressure +analysis type. +ITOTEX = 1: +The value from curve or table is excess head. Total head will be determined by adding +the hydrostatic head. This option cannot be used with drained analysis, which sets +excess head to zero. +ITOTEX = 2: +The value from curve or table is hydraulic head, to which excess head may be added +due to volume change in the soil if the analysis type is not drained. +*BOUNDARY +The curve value is the z-coordinate of the water surface; pore pressure head at any node +in this boundary condition is given by, +𝑧surface − 𝑧node +This option allows a single boundary condition to be used for nodes at any depth, +provided that the pressure distribution is hydrostatic below the given surface. This +option is not available for the TABLE option. +*BOUNDARY_RADIATION_OPTION1_{OPTION2}_{OPTION3} +Available values for OPTION1 include: +SET +SEGMENT +Available values for OPTION2 include: +VF_READ +VF_CALCULATE + +Available values for OPTION3 include: +RESTART + +OPTION1 specifies radiation boundary surface definition by a surface set (SET) or by a +segment list (SEGMENT). +OPTION2 indicates the radiation boundary surface is part of an enclosure. When set to +VF OPTION2 specifies the use of view factors. The suffix, READ, indicates that the +view factors should be read from the file “viewfl”. The suffix, CALCULATE, indicates +that the view factors should be calculated. The Stefan Boltzmann constant must be +defined for radiation in an enclosure on the *CONTROL_THERMAL_SOLVER +keyword. The parameter DTVF entered on the CONTROL_THERMAL_SOLVER +keyword defines the time interval between VF updates for moving geometries. +OPTION3 is the keyword suffix RESTART. This is only applicable in combination with +the keyword VF_CALCULATE. In very long runs, it may be necessary to halt +execution. This is accomplished by entering Ctrl-C followed by sw1. To restart the +view factor calculation, add the suffix RESTART to all VF_CALCULATE keywords in +the input file. +The status of an in-progress view factor calculation can be determined by using the +sense switch. This is accomplished by first typing Control-C followed by: +sw1. +sw2. +Stop run and save viewfl file for restart +Viewfactor run statistics +A list of acceptable keywords are: +*BOUNDARY_RADIATION_SEGMENT +*BOUNDARY_RADIATION_SEGMENT_VF_READ +*BOUNDARY_RADIATION_SEGMENT_VF_CALCULATE +*BOUNDARY_RADIATION_SET +*BOUNDARY_RADIATION_SET_VF_READ +*BOUNDARY_RADIATION_SET_VF_CALCULATE +Remarks: +In models that include radiation boundary conditions, a thermodynamic temperature +scale is required, i.e., zero degrees must correspond to absolute zero. The Kelvin and +Rankine temperature scales meet this requirement whereas Celsius and Fahrenheit +temperature scales do not. +*BOUNDARY_RADIATION_SEGMENT +Include the following 2 cards for each segment. Apply a radiation boundary condition +on a SEGMENT to transfer heat between the segment and the environment. Setting +TYPE = 1 on Card 1 below indicates that the segment transfers heat to the environment. + Card 1 +Variable +1 +N1 +Type +I +2 +N2 +I +3 +N3 +I +4 +N4 +I +Default +none +none +none +none + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +TYPE +I +1 +5 +6 +7 +8 +Variable +FLCID +FMULT +TLCID +TMULT +LOC +Type +I +F +I +F +Default +none +0. +none +0. +I +0 + VARIABLE +DESCRIPTION +N1, N2, +N3, N4 +TYPE +FLCID +Node ID’s defining segment +Radiation type: +EQ.1: Radiation to environment +Radiation heat transfer coefficient, 𝑓 = 𝜎𝜀𝐹, specification where +σ = Stefan Boltzmann constant, ε = surface emissivity, F = surface +view factor. This parameter can reference a load curve ID or a function ID . When the reference is to a curve, FLCID has the +following interpretation: +GT.0: 𝑓 is defined as a function of time, 𝑡, having points +consisting of (𝑡, 𝑓 (𝑡)) data pairs. +EQ.0: 𝑓 is a constant defined by the value FMULT. +VARIABLE +DESCRIPTION +LT.0: 𝑓 is defined as a function of temperature, 𝑇, by a curve +consisting of (𝑇, 𝑓 (𝑇) ) data pairs. Enter |FLCID| on the +DEFINE_CURVE keyword. +FMULT +Radiation heat transfer coefficient, f, curve multiplier for use in +the equation +q̇′′ = 𝜎𝜀𝐹(𝑇surface +− 𝑇∞ +4 ) = 𝑓 (𝑇surface +− 𝑇∞ +4 ) +TLCID +If f is a function of temperature, f is evaluated at the surface +temperature, Tsurface. [σ = Stefan Boltzmann constant, ε = surface +emissivity, F = surface view factor] +Environment temperature, 𝑇∞, specification. This parameter can +reference a load curve ID or a function ID +. When the reference is +to a curve, TLCID has the following interpretation: +GT.0: 𝑇∞ is defined as a function of time, 𝑡, by a curve +consisting of (𝑡, 𝑇∞(𝑡) ) data pairs. +EQ.0: 𝑇∞ a constant defined by the value TMULT. +TMULT +Environment temperature, 𝑇∞, curve multiplier. +LOC +For a thick thermal shell, the radiation will be applied to the +surface identified by LOC. See the parameter THSHEL on the +*CONTROL_SHELL keyword. +EQ.-1: lower surface of thermal shell element +EQ.0: middle surface of thermal shell element +EQ.1: upper surface of thermal shell element +Remarks: +A radiation boundary condition is calculated using +q̇′′ = 𝜎𝜀𝐹(𝑇surface +− 𝑇∞ +4 ) = 𝑓 (𝑇surface +− 𝑇∞ +4 ) +Where, 𝑓 , is the radiation heat transfer coefficient. If 𝑓 is a function of temperature, 𝑓 , +is evaluated at the surface temperature, Tsurface. +1. +If HLCID references a DEFINE_FUNCTION, the following function arguments +are allowed 𝑓 (𝑥, 𝑦, 𝑧, 𝑣𝑥, 𝑣𝑦, 𝑣𝑧, 𝑇, 𝑇∞, 𝑡) where: +𝑥, 𝑦, 𝑧 = segment centroid coordinates +𝑣𝑥, 𝑣𝑦, 𝑣𝑧 = segment centroid velocity component +T = segment centroid temperature +𝑇∞ = environment temperature, T∞ +𝑡 = solution time +2. +If TLCID references a DEFINE_FUNCTION, the following function arguments +are allowed 𝑓 ( 𝑥 , 𝑦 , 𝑧 , 𝑣𝑥, 𝑣𝑦, 𝑣𝑧, 𝑡) where: +𝑥, 𝑦, 𝑧 = segment centroid coordinates +𝑣𝑥, 𝑣𝑦, 𝑣𝑧 = segment centroid velocity components +𝑡 = solution time +*BOUNDARY_RADIATION_SEGMENT_VF_OPTION +Available options include: +READ +CALCULATE +Include the following 2 cards for each segment. Apply a radiation boundary condition +on a SEGMENT to transfer heat between the segment and an enclosure surrounding the +segment using view factors. The enclosure is defined by additional segments using this +keyword. Setting TYPE = 2 on Card 1 below specifies that the segment belongs to an +enclosure. +The file “viewfl” must be present for the READ option, whereas it will be created with +the CALCULATE option. If the file “viewfl” exists when using the CALCULATE +option, LS-DYNA will terminate with an error message to prevent overwriting the file. +The file “viewfl” contains the surface-to-surface area × view factor products (i.e., 𝐴𝑖𝐹𝑖𝑗). +These products are stored by row and formatted as 5E16.0. + Card 1 +Variable +1 +N1 +Type +I +2 +N2 +I +3 +N3 +I +4 +N4 +I +Default +none +none +none +none + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +TYPE +BLOCK +NINT +I +2 +5 +I +0 +6 +I +0 +7 +8 +Variable +SELCID +SEMULT +Type +I +F +Default +none +0. + VARIABLE +DESCRIPTION +N1, N2, +N3, N4 +Node ID’s defining segment +VARIABLE +DESCRIPTION +TYPE +Radiation type: +EQ.2: Radiation within an enclosure +BLOCK +Flag indicating if this surface blocks the view between any other 2 +surfaces. +EQ.0: no blocking (default) +EQ.1: blocking +NINT +Number of integration points for viewfactor calculation +EQ.0: +LS-DYNA determines the number of integration +points based on the segment size and separation +distance +1 ≤ NINT ≤ 10: User specified number +SELCID +Load curve ID for surface emissivity, see *DEFINE_CURVE +GT.0: function versus time +EQ.0: use constant multiplier value, SEMULT +LT.0: function versus temperature. The value of –SELCID +must be an integer, and it is interpreted as a load curve +ID. See the DEFINE_CURVE keyword. +SEMULT +Curve multiplier for surface emissivity, see *DEFINE_CURVE +*BOUNDARY +Include the following 2 cards for each set. Apply a radiation boundary condition on a +SEGMENT_SET to transfer heat between the segment set and the environment Setting +TYPE = 1 on Card 1 below indicates that the segment transfers energy to the +environment. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SSID +TYPE +Type +I +Default +none + Card 2 +1 +I +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FLCID +FMULT +TLCID +TMULT +LOC +Type +I +F +I +F +Default +none +0. +none +0. +I +0 + VARIABLE +SSID +DESCRIPTION +SSID specifies the ID for a set of segments that comprise a portion +of, or possibly, the entire enclosure. See *SET_SEGMENT. +TYPE +Radiation type: +EQ.1: Radiation to environment +FLCID +Radiation heat transfer coefficient, 𝑓 = 𝜎𝜀𝐹, specification where +σ = Stefan Boltzmann constant, ε = surface emissivity, F = surface +view factor. This parameter can reference a load curve ID or a function ID . When the reference is to a curve, FLCID has the +following interpretation: +GT.0: 𝑓 is defined as a function time, 𝑡, by a curve consisting of +(𝑡, 𝑓 (𝑡)) data pairs. +VARIABLE +DESCRIPTION +EQ.0: 𝑓 is a constant defined by the value FMULT. +LT.0: 𝑓 is defined as a function of temperature, 𝑇, by a curve +consisting of (𝑇, 𝑓 (𝑇)) data pairs. Enter |-FLCID| on +the DEFINE_CURVE keyword +FMULT +Curve multiplier for f for use in the equation +q̇′′ = 𝜎𝜀𝐹(𝑇surface +− 𝑇∞ +4 ) = 𝑓 (𝑇surface +− 𝑇∞ +4 ) +TLCID +If f is a function of temperature, f is evaluated at the surface +temperature, Tsurface. [σ = Stefan Boltzmann constant, ε = surface +emissivity, F = surface view factor] +Environment temperature, 𝑇∞ , specification. This parameter can +reference a load curve ID or a function ID +. When the reference is +to a curve, TLCID has the following interpretation: +GT.0: 𝑇∞ is defined as a function of time, 𝑡, by a curve +consisting of (𝑡, 𝑇∞(𝑡)) data pairs. +EQ.0: 𝑇∞ a constant defined by the value TMULT +TMULT +Curve multiplier for 𝑇∞ +LOC +For a thick thermal shell, the radiation will be applied to the +surface identified by LOC. See the parameter THSHEL on the +*CONTROL_SHELL keyword. +EQ.-1: lower surface of thermal shell element +EQ.0.: middle surface of thermal shell element +EQ.1: upper surface of thermal shell element +Remarks: +A radiation boundary condition is calculated using +q̇′′ = 𝜎𝜀𝐹(𝑇surface +− 𝑇∞ +4 ) = 𝑓 (𝑇surface +− 𝑇∞ +4 ) +Where, f , is the radiation heat transfer coefficient. . If f is a function of temperature, f, +is evaluated at the surface temperature, Tsurface. +1. +If HLCID references a DEFINE_FUNCTION, the following function arguments +are allowed 𝑓 (𝑥, 𝑦, 𝑧, 𝑣𝑥, 𝑣𝑦, 𝑣𝑧, 𝑇, 𝑇∞, 𝑡) where: +𝑥, 𝑦, 𝑧 = segment centroid coordinates +𝑣𝑥, 𝑣𝑦, 𝑣𝑧 = segment centroid velocity component +𝑇 = segment centroid temperature +𝑇∞ = environment temperature, T∞ +𝑡 = solution time +2. +If TLCID references a DEFINE_FUNCTION, the following function arguments +are allowed 𝑓 (𝑥, 𝑦, 𝑧, 𝑣𝑥, 𝑣𝑦, 𝑣𝑧, 𝑡) where: +𝑥, 𝑦, 𝑧 = segment centroid coordinates +𝑣𝑥, 𝑣𝑦, 𝑣𝑧 = segment centroid velocity components +𝑡 = solution time +*BOUNDARY_RADIATION_SET_VF_OPTION +Available options include: +READ +CALCULATE +Include the following 2 cards for each set. Apply a radiation boundary condition on a +SEGMENT_SET to transfer heat between the segment set and an enclosure surrounding +the segments using view factors. Segments contained in the SEGMENT_SET may form +the enclosure. Setting TYPE = 2 on Card 1 below specifies that the segment set belongs +to an enclosure. +The file “viewfl” must be present for the READ option. The file “viewfl” will be created +for the CALCULATE option. If the file “viewfl” exists when using the CACULATE +option, LS-DYNA will terminate with an error message to prevent overwriting the file. +The file “viewfl” contains the surface-to-surface area × view factor products (i.e. 𝐴𝑖𝐹𝑖𝑗). +These products are stored by row and formatted as 5E16.0. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SSID +TYPE +RAD_GRP FILE_NO +BLOCK +NINT +Type +I +Default +none + Card 2 +1 +I +2 +2 +I +0 +3 +I +0 +4 +I +0 +5 +I +0 +6 +7 +8 +Variable +SELCID +SEMULT +Type +I +F +Default +none +0. + VARIABLE +SSID +DESCRIPTION +SSID specifies the ID for a set of segments that comprise a portion +of, or possibly, the entire enclosure. See *SET_SEGMENT. +VARIABLE +DESCRIPTION +TYPE +Radiation type: +EQ.2: Radiation within an enclosure +RAD_GRP +FILE_NO +Radiation enclosure group ID. The segment sets from all +radiation enclosure definitions with the same group ID are +augmented to form a single enclosure definition. If RAD_GRP is +not specified or set to zero, then the segments are placed in group +zero. All segments defined by the SEGMENT option are placed +in set zero. +File number for view factor file. FILE_NO is added to “viewfl_” +to form the name of the file containing the view factors. For +example if FILE_NO is specified as 22, then the view factors are +read from viewfl_22. For radiation enclosure group zero FILE_- +NO is ignored and view factors are read from viewfl. The same +file may be used for different radiation enclosure group +definitions. +BLOCK +Flag indicating if this surface blocks the view between any other 2 +surfaces. +EQ.0: no blocking (default) +EQ.1: blocking +NINT +Number of integration points for viewfactor calculation +EQ.0: LS-DYNA determines the number of integration points +based on the segment size and separation distance +GE.11: Not allowed +SELCID +Load curve ID for surface emissivity, see *DEFINE_CURVE +GT.0: function versus time +EQ.0: use constant multiplier value, SEMULT +LT.0: function versus temperature. Enter –SELCID as |- +SELCID| on the DEFINE_CURVE keyword. +SEMULT +Curve multiplier for surface emissivity, see *DEFINE_CURVE +*BOUNDARY_RADIATION_SET_VF +Multiple enclosures can be modeled when using view factors. Consider the following +example input. The order of segments in the view factor file follows the order the sets +are assigned to the boundary radiation definition. +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *BOUNDARY_RADIATION_SET +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Make boundary enclosure radiation groups 8 and 9. +$ +*BOUNDARY_RADIATION_SET_VF_READ +* SSID TYPE RAD_GRP FILE_NO + 15 2 9 10 + 1.0 1.0 +*BOUNDARY_RADIATION_SET_VF_READ +* SSID TYPE RAD_GRP FILE_NO + 12 2 9 10 + 1.0 1.0 +*BOUNDARY_RADIATION_SET_VF_READ +* SSID TYPE RAD_GRP FILE_NO + 13 2 8 21 + 1.0 1.0 +$ +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +Enclosure radiation group 9 is composed of all the segments in segment set 15 followed +by those in segment set 12. The view factors are stored in the file viewfl_10. Enclosure +radiation group 8 is composed of the segments in segment set 13. The view factors are +stored in the file viewfl_21. +*BOUNDARY +Purpose: Define a sliding symmetry plane. This option applies to continuum domains +modeled with solid elements. + Card 1 +1 +Variable +NSID +Type +I +Default +none +2 +VX +F +0 +3 +VY +F +0 +4 +VZ +F +0 +5 +6 +7 +8 +COPT +I +0 + VARIABLE +DESCRIPTION +NSID +Nodal set ID, see *SET_NODE +VX +VY +VZ +x-component of vector defining normal or vector +y-component of vector defining normal or vector +z-component of vector defining normal or vector +COPT +Option: +EQ.0: node moves on normal plane, +EQ.1: node moves only in vector direction. +Remarks: +Any node may be constrained to move on an arbitrarily oriented plane or line +depending on the choice of COPT. Each boundary condition card defines a vector +originating at (0, 0, 0) and terminating at the coordinates defined above. Since an +arbitrary magnitude is assumed for this vector, the specified coordinates are non- +unique and define only a direction. Use of *BOUNDARY_SPC is preferred over +*BOUNDARY_SLIDING_PLANE as the boundary conditions imposed via the latter +have been seen to break down somewhat in lengthy simulations owing to numerical +roundoff. +*BOUNDARY_SPC_OPTION1_{OPTION2}_{OPTION3} +OPTION1 is required since it specifies whether the SPC applies to a single node or to a +set. The two choices are: +NODE +SET +OPTION2 allows optional birth and death times to be assigned the single node or node +set: +BIRTH_DEATH +This option requires one additional line of input. The BIRTH_DEATH option is inactive +during the dynamic relaxation phase, which allows the SPC to be removed during the +subsequent normal analysis phase. The BIRTH_DEATH option can be used only once +for any given node and if used, no other *BOUNDARY_SPC commands can be used for +that node. +OPTION3 allows an optional ID to be given that applies either to the single node or to +the entire set: +ID +If a heading is defined with the ID, then the ID with the heading will be written at the +beginning of the ASCII file, spcforc. +Purpose: Define nodal single point constraints. Do not use this option in r-adaptive +problems since the nodal point ID's change during the adaptive step. If possible use +CONSTRAINED_GLOBAL instead. +ID Card. Additional card for the ID keyword option. + Optional +Variable +1 +ID +Type +I +2 +3 +4 +5 +6 +7 +8 +HEADING +A70 +Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable NID/NSID +CID +DOFX +DOFY +DOFZ +DOFRX +DOFRY +DOFRZ +Type +I +Default +none +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +Birth/Death Card. Additional card for the BIRTH_DEATH keyword option. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +BIRTH +DEATH +Type +F +F +Default +0.0 +1020 + VARIABLE +DESCRIPTION +ID +Optional SPC set ID to which this node or node set belongs. This +ID does not need to be unique +HEADING +An optional SPC descriptor that will be written into the d3hsp file +and the spcforc file. +NID/NSID +Node ID or nodal set ID, see *SET_NODE. +CID +DOFX +DOFY +DOFZ +Coordinate system ID, see *DEFINE_COORDINATE_SYSTEM. +Insert 1 for translational constraint in local 𝑥-direction. +Insert 1 for translational constraint in local 𝑦-direction. +Insert 1 for translational constraint in local 𝑧-direction. +DOFRX +Insert 1 for rotational constraint about local 𝑥-axis. +DOFRY +Insert 1 for rotational constraint about local 𝑦-axis. +DOFRZ +Insert 1 for rotational constraint about local 𝑧-axis. +VARIABLE +DESCRIPTION +Activation time for SPC constraint. The birth time is ignored +during dynamic relaxation. +Deactivation time for the SPC constraint. The death time is +ignored during dynamic relaxation. +BIRTH +DEATH +Remarks: +Constraints are applied if for each DOFij field set to 1. A value of zero means no +constraint. No attempt should be made to apply SPCs to nodes belonging to rigid +bodies . +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *BOUNDARY_SPC_NODE +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Make boundary constraints for nodes 6 and 542. +$ +*BOUNDARY_SPC_NODE +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ nid cid dofx dofy dofz dofrx dofry dofrz + 6 0 1 1 1 1 1 1 + 542 0 0 1 0 1 0 1 +$ +$ Node 6 is fixed in all six degrees of freedom (no motion allowed). +$ +$ Node 542 has a symmetry condition constraint in the x-z plane, +$ no motion allowed for y translation, and x & z rotation. +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +*BOUNDARY_SPC_SYMMETRY_PLANE_{OPTION} +This keyword is developed to create nodal symmetric constraints by defining a +symmetric plane. +Available options include: + +SET +The option SET allows for symmetric boundary conditions to be applied on tailor- +welded blanks (TWB). +Card Sets. For each symmetry plane input one pair of cards 1 and 2. This input ends at +the next keyword (“*”) card. + Card 1 +1 +2 +Variable +IDSP +PID/PSID +Type +I +I +3 +X +F +4 +Y +F +5 +Z +F +6 +VX +F +7 +VY +F +8 +VZ +F +Default +none +none +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TOL +Type +F +Default +0.0 + VARIABLE +DESCRIPTION +IDSP +Identification number of the constraint. Must be unique. +PID/PSID +A part ID of the deformable part (sheet metal blank, for example) +on which the constraints will be imposed. When the option SET +is invoked, a part set ID can be input. +VX, VY, VZ +X, Y, Z +TOL +TOL +All nodes within +/- TOL of the plane defined +by the point with coordinate (X, Y, Z) and the +plane with normal vector (VX, VY, VZ) will be +constrained symmetrically. + Figure 5-5. Define symmetry constraints using the variables in the keyword. + VARIABLE +DESCRIPTION +X, Y, Z +Position coordinates on the symmetry plane. +VX, VY, VZ +Vector components of the symmetry plane normal. +TOL +A distance tolerance value within which the nodes on the +deformable part will be constrained. +Remarks: +1. Adaptive refined nodes generated along the symmetry plane during simulation +are automatically included in the constraints. +2. Figure 5-5 shows an example of applying symmetry constraints using the +variables in the keyword. +3. The following keyword creates symmetric constraints on nodes (from PID 11) +within distance of 0.1mm from the defined symmetry plane (with normal vec- +tors [1.0,1.0,1.0]) that goes through point coordinates (10.5, 40.0, 20.0): +*BOUNDARY_SPC_SYMMETRY_PLANE +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ IDSP PID X Y Z VX VY VZ + 1 11 10.5 40.0 20.0 1.0 1.0 1.0 +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ TOL +4. The following keywords create two symmetric constraints on nodes from part +set ID 99 (which includes part IDs 13 and 14) within distance of 0.1mm from +two defined symmetry planes (with normal vectors [1.0, 0.0, 0.0] and [0.0, 1.0, +0.0], respectively) that all go through point coordinates (-76.0, 35.6, 0.0). Note +the two point coordinates that define the two symmetry planes must be exactly +the same. +*SET_PART_LIST +99 +13,14 +*BOUNDARY_SPC_SYMMETRY_PLANE_SET +$ IDSP PID X Y Z VX VY VZ + 1 99 -76.0 35.6 0.0 1.0 +$ TOL + 0.10 + 2 99 -76.0 35.6 0.0 0.0 1.0 +$ TOL + 0.10 +Revision information: +This feature is available starting in Revision 85404. The option SET is available starting +in Revision 113355. +*BOUNDARY_SPH_FLOW +Purpose: Define a flow of particles. This option applies to continuum domains +modeled with SPH elements. + Card 1 +Variable +1 +ID +2 +3 +4 +5 +STYP +DOF +VAD +LCID +6 +SF +F +7 +8 +DEATH +BIRTH +F +F +I +none +1. +1.E+20 +0.0 +5 +6 +7 +8 +I +0 +4 +Type +I +I +I +Default +none +none +none + Card 2 +1 +2 +3 +Variable +NODE +VID +Type +I +Default +none +I +0 + VARIABLE +NSID, PID +DESCRIPTION +Nodal set ID (NSID), SEE *SET_NODE, or part ID (PID), see +*PART. +STYP +Set type: +EQ.1: part set ID, see *SET_PART, +EQ.2: part ID, see *PART, +EQ.3: node set ID, see *NODE_SET, +Node +boundary +vector VID +deactivated particle +activated particle +SPH Flow +Figure 5-6. Vector VID determines the orientation of the SPH flow + VARIABLE +DESCRIPTION +DOF +Applicable degrees-of-freedom: +EQ.1: x-translational degree-of-freedom, +EQ.2: y-translational degree-of-freedom, +EQ.3: z-translational degree-of-freedom, +EQ.4: translational motion in direction given by the VID. +Movement on plane normal to the vector is permitted. +VAD +Velocity/Acceleration/Displacement +elements before activation: +flag applied +to SPH +EQ.0: velocity, +EQ.1: acceleration, +EQ.2: displacement. +LCID +Load curve ID to describe motion value versus time, see *DE- +FINE_CURVE. +SF +Load curve scale factor. (default = 1.0) +DEATH +Time imposed motion/constraint is removed: +EQ.0.0: default set to 1020. +BIRTH +Time imposed motion/constraint is activated. +VARIABLE +NODE +DESCRIPTION +Node fixed in space which determines the boundary between +activated particles and deactivated particles. +VID +Vector ID for DOF value of 4, see *DEFINE_VECTOR +Remarks: +Initially, the user defines the set of particles that are representing the flow of particles +during the simulation. At time t = 0, all the particles are deactivated which means that +no particle approximation is calculated. The boundary of activation is a plane +determined by the NODE, and normal to the vector VID. The particles are activated +when they reached the boundary. Since they are activated, particle approximation is +started. +*BOUNDARY_SPH_NON_REFLECTING +Purpose: Define a non-reflecting boundary plane for SPH. This option applies to +continuum domains modeled with SPH elements. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +VTX +VTY +VTZ +VHX +VHY +VHZ +Type +F +Default +0. +F +0. +F +0. +F +0. +F +0. +F +0. + VARIABLE +DESCRIPTION +x-coordinate of tail of a normal vector originating on the wall +(tail) and terminating in the body (head) (i.e., vector points from +the non-reflecting boundary plane into the body). +y-coordinate of tail +z-coordinate of tail +x-coordinate of head +y-coordinate of head +z-coordinate of head +VTX +VTY +VTZ +VHX +VHY +VHZ +Remarks: +1. The non-reflecting boundary plane has to be normal to either the x, y or z +direction. +*BOUNDARY_SPH_SYMMETRY_PLANE +Purpose: Define a symmetry plane for SPH. This option applies to continuum domains +modeled with SPH elements. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +VTX +VTY +VTZ +VHX +VHY +VHZ +Type +F +Default +0. +F +0. +F +0. +F +0. +F +0. +F +0. + VARIABLE +DESCRIPTION +x-coordinate of tail of a normal vector originating on the wall +(tail) and terminating in the body (head) (i.e., vector points from +the symmetry plane into the body). +y-coordinate of tail +z-coordinate of tail +x-coordinate of head +y-coordinate of head +z-coordinate of head +VTX +VTY +VTZ +VHX +VHY +VHZ +Remarks: +1. A plane of symmetry is assumed for all SPH elements defined in the model. +2. The plane of symmetry has to be normal to either the x, y or z direction. +3. For axi-symmetric SPH analysis, IDIM = -2, a plane of symmetry centered at the +global origin and normal to x-direction is automatically created by LS-Dyna. +*BOUNDARY_SYMMETRY_FAILURE +Purpose: Define a symmetry plane with a failure criterion. This option applies to +continuum domains modeled with solid elements. + Card 1 +1 +Variable +SSID +Type +I +2 +FS +F +Default +none +0. +3 +4 +5 +6 +7 +8 +VTX +VTY +VTZ +VHX +VHY +VHZ +F +0. +F +0. +F +0. +F +0. +F +0. +F +0. + VARIABLE +DESCRIPTION +Segment set ID, see *SET_SEGMENT +Tensile failure stress > 0.0. The average stress in the elements +surrounding the boundary nodes in a direction perpendicular to +the boundary is used. +x-coordinate of tail of a normal vector originating on the wall +(tail) and terminating in the body (head) (i.e., vector points from +the symmetry plane into the body). +y-coordinate of tail +z-coordinate of tail +x-coordinate of head +y-coordinate of head +z-coordinate of head +SSID +FS +VTX +VTY +VTZ +VHX +VHY +VHZ +Remarks: +A plane of symmetry is assumed for the nodes on the boundary at the tail of the vector +given above. Only the motion perpendicular to the symmetry plane is constrained. +After failure the nodes are set free. +*BOUNDARY_TEMPERATURE_OPTION +Available options include: +NODE +SET +Purpose: Define temperature boundary conditions for a thermal or coupled thermal/ +structural analysis. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NID/SID +TLCID +TMULT +LOC +Type +I +Default +none +I +0 +F +0. +I +0 + VARIABLE +DESCRIPTION +NID/SID +Node ID/Node Set ID, see *SET_NODE_OPTION +TLCID +Temperature, 𝑇, specification. This parameter can reference a +load curve ID or a function ID . When the reference is to a +curve, TLCID has the following interpretation: +GT.0: 𝑇 is defined by a curve consisting of (𝑡, 𝑇) data pairs. +EQ.0: 𝑇 is a constant defined by the value TMULT. +TMULT +Temperature, 𝑇, curve multiplier. +LOC +Application of surface for thermal shell elements, see parameter, +THSHEL, in the *CONTROL_SHELL input: +EQ.-1: lower surface of thermal shell element +EQ.0: middle surface of thermal shell element +EQ.1: upper surface of thermal shell element +Remarks: +1. This keyword can be used to apply temperature boundary conditions to SPH +particles. +2. +If TLCID references a DEFINE_FUNCTION, the following function arguments +are allowed 𝑓 (𝑥, 𝑦, 𝑧, 𝑣𝑥, 𝑣𝑦, 𝑣𝑧, 𝑡): +𝑥, 𝑦, 𝑧 = node point coordinates +𝑣𝑥, 𝑣𝑦, 𝑣𝑧 = node point velocity components +𝑡 = solution time +*BOUNDARY_THERMAL_BULKFLOW_OPTION1_OPTION2 +Purpose: Used to define bulk fluid flow elements. +OPTION1 is required since it specifies whether the BULKFLOW applies to an element +or set. +ELEMENT +SET +OPTION2 if used turns on the fluid upwind algorithm +UPWIND + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EID/SID +LCID +MDOT +Type +I +I +F +Default +none +none +none + VARIABLE +EID / SID +DESCRIPTION +Beam element ID (EID) for ELEMENT option +Beam set ID (SID) for SET option +LCID +Load Curve ID for mass flow rate versus time. +MDOT +Mass flow rate (e.g. kg/sec). +*BOUNDARY_THERMAL_BULKNODE +Purpose: Used to define thermal bulk nodes. + Card 1 +1 +2 +3 +4 +5 +Variable +NID +PID +NBNSEG +VOL +LCID +Type +I +I +Default +none +none +I +0 +F +none +I +0 +6 +H +F +0. +7 +8 +AEXP +BEXP +F +0. +F +0. +Bulk Node Cards. Include NBNSEG cards, one for each bulk node segment. + Card 2 +Variable +1 +N1 +Type +I +2 +N2 +I +3 +N3 +I +4 +N4 +I +5 +6 +7 +8 + VARIABLE +DESCRIPTION +NID +PID +VOL +Bulk node number. +Bulk node part ID. +Bulk node volume. +NBNSEG +Number of element surface segments that transfer heat with +this bulk node. +N1, N2, N3, N4 +Nodal point numbers +LCID +H +AEXP +BEXP +Load curve ID for H +Heat transfer coefficient +𝑎 exponent +𝑏 exponent +*BOUNDARY_THERMAL_BULKNODE +The heat flow between a bulk node (TB) and a bulk node segment (TS) is given by +𝑞 = ℎ(𝑇𝐵 +𝑎 − 𝑇𝐵 +𝑎 )𝑏 +1. For convection, set 𝑎 = 𝑏 = 1. +2. For radiation, set 𝑎 = 4, 𝑏 = 1. +3. For flux, set 𝑎 = 𝑏 = 0. Mathematically, anything to the 0 power is 1. This += (1 − 1)0 = 00 = 1. However, some com- +to set +It +produces the expression, (𝑇𝐵 +puter operating systems don’t +𝑎 = 𝑏 = very small number. +recognize 00. +0) +0−𝑇𝑆 +is safer +*BOUNDARY_THERMAL_WELD +Purpose: Define a moving heat source to model welding. Only applicable for a coupled +thermal-structural simulations in which the weld source or work piece is moving. + Card 1 +1 +2 +3 +4 +Variable +PID +PTYP +NID +NFLAG +Type +I +Default +none + Card 2 +Variable +Type +1 +a +F +I +1 +2 +b +F +I +none +3 +cf +F +I +1 +4 +cr +F +5 +X0 +F +6 +Y0 +F +7 +Z0 +F +8 +N2ID +I +none +none +none +none +5 +LCID +I +6 +Q +F +7 +Ff +F +8 +Fr +F +Default +none +none +none +none +none +none +none +none +Beam Aiming Direction Card. Additional card for N2ID = -1. +4 +5 +6 +7 +8 + Optional +Variable +1 +TX +Type +F +2 +TY +F +3 +TZ +F +Default +none +none +none + VARIABLE +DESCRIPTION +PID +PTYP +Part ID or Part Set ID to which weld source is applied +PID type: +EQ.1: PID defines a single part ID +EQ.2: PID defines a part set ID +Welding +Torch +velocity +cr +cf +(a) +(b) +Figure 5-7. Schematic illustration of welding with moving torch. The left +figure (a) shows the surface of the material from above, while the right figure +(b) shows a slice along the dotted line in the y-z plane. + VARIABLE +DESCRIPTION +NID +Node ID giving location of weld source +EQ.0: location defined by (X0, Y0, Z0) below +NFLAG +Flag controlling motion of weld source +EQ.1: source moves with node NID +EQ.2: source is fixed in space at original position of node NID +X0, Y0, Z0 +Coordinates of weld source, which remains fixed in space +(optional, ignored if NID nonzero above) +N2ID +Second node ID for weld beam aiming direction +GT.0: beam is aimed from N2ID to NID, moves with these +nodes +EQ.-1: beam aiming direction is (tx, ty, tz) input on optional +card 3 +a +b +cf +cr +Weld pool radius (i.e., half width) +Weld pool depth (in beam aiming direction) +Weld pool forward direction +Weld pool rearward direction +VARIABLE +DESCRIPTION +LCID +Load curve ID for weld energy input rate vs. time +EQ.0: use constant multiplier value Q. +Q +Ff +Fr +Curve multiplier for weld energy input rate [energy/time, e.g., +Watt] +LT.0: use absolute value and accurate integration of heat +Forward distribution function +Rear distribution function (Note:Ff + Fr = 2.0) +TX, TY, TZ +Weld beam direction vector in global coordinates (N2ID = -1 +only) +Remarks: +This boundary condition allows simulation of a moving weld heat source, following the +work of Goldak, Chakravarti, and Bibby [1984]. Heat is generated in an ellipsoidal +region centered at the weld source, and decaying exponentially with distance according +to: +where: +𝑞 = +6√3𝐹𝑄 +𝜋√𝜋𝑎𝑏𝑐 +exp ( +−3𝑥2 +𝑎2 ) exp ( +−3𝑦2 +𝑏2 ) exp ( +−3𝑧2 +𝑐2 ) +𝑞 = weld source power density +(𝑥, 𝑦, 𝑧) = coordinates of point 𝑝 in weld material +𝐹 = { +𝑐 = { +Ff if point 𝑝 is in front of beam +Fr if point 𝑝 is behind beam +cf if point 𝑝 is in front of beam +cr if point 𝑝 is behind beam +A local coordinate system is constructed which is centered at the heat source. The +relative velocity vector of the heat source defines the "forward" direction, so material +points that are approaching the heat source are in "front" of the beam. The beam aiming +direction is used to compute the weld pool depth. The weld pool width is measured +normal to the relative velocity - aiming direction plane. If Q is defined negative in the +input, then the formula above is using the absolute value of Q, and a more accurate +integration of the heat source is performed with some additional cost in CPU time. +To simulate a welding process during which the welding torch is fixed in space, NID +and N2ID must be set to 0 and -1 respectively. The X0, Y0, and Z0 fields specify the +global coordinates of the welding torch, and the TX, TY, and TZ fields specify the +direction of the welding beam. The motion of the work piece is prescribed using the +*BOUNDARY_PRESCRIBED_MOTION keyword. +To simulate a welding process for which the work piece fixed in space, NID and N2ID +specify both the beam source location and direction. The X0, Y0, Z0, TX, TY, and TZ +fields are ignored. The motion of welding source is prescribed with using the *BOUND- +ARY_PRESCRIBED_MOTION keyword applied to the two nodal points specified in the +NID and N2ID fields. +*BOUNDARY_THERMAL_WELD_TRAJECTORY +Purpose: Define a moving heat source to model welding of solid or shell structures. +Motion of the source is described by a nodal path and a prescribed velocity on this path. +This keyword is applicable in coupled thermal-structural and thermal-only simulations +and also supports thermal dumping. Different equivalent heat source descriptions are +implemented. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID +PTYP +NSID1 +VEL1 +SID2 +VEL2 +NCYC +RELVEL +Type +I +Default +none + Card 2 +1 +I +1 +2 +Variable +IFORM +LCID +Type +I +I +I +F +I +F +none +none +none +none +3 +Q +F +4 +5 +6 +LCROT +LCMOV +LCLAT +DISC +I +I +I +F +I +1 +7 +Default +none +none +none +none +none +none +none + Card 3 +Variable +1 +P1 +Type +F +2 +P2 +F +3 +P3 +F +4 +P4 +F +5 +P5 +F +6 +P6 +F +7 +P7 +F +I +0 +8 +8 +P8 +F +Default +none +none +none +none +none +none +none +none +Weld Source Aiming Direction Card. Additional card for NS2ID = 0. +4 +5 +6 +7 +8 + Optional +Variable +1 +TX +Type +F +2 +TY +F +3 +TZ +F +Default +none +none +none + VARIABLE +PID +DESCRIPTION +Part ID or Part Set ID of solids or shells to which weld source is +applied +PTYP +PID type: +EQ.1: PID defines a single part ID +EQ.2: PID defines a part set ID +NSID1 +Node set ID containing the path (weld trajectory) information for +the weld source movement. A sorted node set is requested. The +order defines the weld path and the direction . +VEL1 +Velocity of the heat source on the weld trajectory +GT.0: constant velocity +LT.0: |VEL1| is a load curve ID defining weld speed vs. time +SID2 +ID of second node set or segment set containing information for +the weld source aiming direction +GT.0: SID2 refers to a sorted node set, the order of which +defines the direction of the trajectory. The heat source is +aimed from current position in SID2 to current position +in the weld trajectory. +EQ.0: beam aiming direction is (tx, ty, tz) input on optional +card 4. +LT.0: |SID2| is a segment set. The heat source is aiming in +normal direction to segments in the set. +VARIABLE +DESCRIPTION +VEL2 +Velocity of reference point in SID2, if SID2 > 0 +GT.0: constant velocity +LT.0: |VEL2| is a load curve ID defining weld speed vs. time +NCYC +RELVEL +Number of substeps for subcycling in evaluation of boundary +condition. Allows thermal dumping . +Defines if VEL1 and VEL2 are relative or absolute velocities in +coupled simulations +EQ.0: absolute velocities +EQ.1: relative velocities with respect to underlying structure +IFORM +Geometry description for energy rate density distribution : +EQ.1: Goldak-type heat source +EQ.2: double ellipsoidal heat source with constant density +EQ.3: double conical heat source with constant density +EQ.4: frustum-shaped heat source with constant density +LCID +Load curve ID for weld energy input rate vs. time +EQ.0: use constant multiplier value Q. +Q +Curve multiplier for weld energy input rate [energy/time] +LT.0: take absolute value and accurate integration of heat using +integration cells with edge length DISC. +LCROT +LCMOV +LCLAT +DISC +Load curve defining the rotation (angle in degree) of weld source +around the trajectory as function of time . +Load curve for offset of weld source in direction of the weld beam +as function of time +Load curve for lateral offset of weld source as function of time + +Resolution for accurate integration, parameter defines edge +length for integration cubes. Default is 5% of weld pool depth. +VARIABLE +DESCRIPTION +Pi +Parameters defining for weld pool geometry, depending on +parameter IFORM. See Remark 4 for details. +TX, TY, TZ +Weld beam direction vector in global coordinates (SID2 = 0 only) +Remarks: +1.This keyword can be applied for solid and thermal thick shells in thermal-only and +coupled thermal-structural simulations. The nodes in the node set NSID1 have +to be ordered, such that the node set defines the path geometry as well as the +direction of the trajectory. The heat source starts at the position of the first node +in the node set and automatically ends as soon as the last node is reached. +By choosing nodes of the work piece for the path definition in NSID1, it can be +ensured that the heat source always follows the movement of the piece. By +setting parameter RELVEL to 1 the velocity of the heat source can even be de- +fined relatively to the motion of the structure. +2.If a segment set referred to in SID2 which coincides with the work piece surface, +the weld beam direction is always orthogonal to the work piece surface. To be +applicable every two consecutive nodes of node set NSID1 have to be part of at +least one segment. In case of more than one segment an averaged normal is +computed. +Based on the trajectory and the weld source aiming direction, a local coordinate +system is constructed that is centered at the root of the heat source. By default, +the relative velocity vector (on the trajectory) of the heat source defines the +"forward" direction 𝒓, so material points that are approaching the heat source are +in "front" of the beam. The weld source aiming direction, denoted by 𝒕, is used to +compute the weld pool depth. The weld pool width (coordinate direction 𝒔) is +measured normal to the relative velocity - aiming direction plane. +The keyword allows rotating and translating the coordinate system. First, the +system is rotated around the vector 𝒓 by a value given in the load curve LCROT +resulting in a new local coordinate system (𝒓, 𝒔′, 𝒕′). Second, the system is trans- +lated in directions 𝒕′ and 𝒔′ using LCMOV and LCLAT, respectively. +3.The subcycling method introduces an individual time step size for the weld source +evaluation. Within one time step of the heat transfer solver, NCYC steps are +used to determine the energy rate distribution of the boundary condition. In +each substep the geometry of the weld pool is updated. Therefore, even with +larger thermal time steps a relatively smooth temperature field around the weld +source can be obtained and a jumping heat source across elements can be sup- +pressed. +4.This keyword allows application of different equivalent heat source geometries, +depending on the parameter IFORM. The definition of the local coordinate +system needed for the description of the weld pool shape is discussed in Remark +2. +For IFORM.EQ.1 heat is generated in an ellipsoidal region centered at the weld +source, and decaying exponentially with distance according to the work of +Goldak, Chakravarti, and Bibby [1984]. Energy rate distribution is governed by +𝑞 = +2𝑛√𝑛𝐹𝑄 +𝜋√𝜋𝑎𝑏𝑐 +exp ( +−𝑛𝑥2 +𝑎2 ) exp ( +−𝑛𝑦2 +𝑏2 ) exp ( +−𝑛𝑧2 +𝑐2 ) +where: +𝐹 = { +𝑐 = { +Ff if point 𝑝 is in front of beam +Fr if point 𝑝 is behind beam +cf if point 𝑝 is in front of beam +cr if point 𝑝 is behind beam +The local coordinates of point 𝑝 are denoted by (𝑥, 𝑦, 𝑧) and it is expected that the +sum of the weighting factors 𝐹f, 𝐹r equals 2. The half-width of the ellipsoid is +given by 𝑎, the welding depth by 𝑏. The complete set of parameters +(𝑎, 𝑏, 𝑐f, 𝑐r, 𝐹f, 𝐹r, 𝑛) is input by the parameters P1 to P7, see table below. +The energy rate density 𝑞 defined by IFORM.EQ.2 is assumed to be constant in +the double ellipsoidal region as defined for Goldak-type heat sources. Its value +is given by +𝑞 = +3𝐹𝑄 +2𝜋𝑎𝑏𝑐 +with the same assumptions for 𝐹 and 𝑐 as above. The set of parameters conse- +quently reduces to (𝑎, 𝑏, 𝑐f, 𝑐r, 𝐹f, 𝐹r), the input of which is given by P1 to P6. +In contrast to the above IFORM.EQ.3 defines an equivalent heat source with a +constant energy rate density on a double conical region. The shape is defined by +three radii 𝑟1, 𝑟2, 𝑟3and two values 𝑏1, 𝑏2 defining the heights of the two parts of +the shape. The respective power densities of the parts are given by +𝑞𝑖 = +3𝐹𝑖𝑄 +2 + 𝑟𝑖+1 +2𝜋𝑏𝑖(𝑟𝑖 +2 + 𝑟𝑖 +2 ) +2𝑟𝑖+1 +. +Here it is assumed that 𝑖 = 1 corresponds to the part closer to the weld source. +The input for the complete parameter set (𝑟1, 𝑟2, 𝑟3, 𝑏1, 𝑏2, 𝐹1, 𝐹2) is again defined +by P1 to P7. +Finally, IFORM.EQ.4 defines a constant power density over a frustum. The +density and the shape can easily be described using three geometrical parameters +P1 to P3 corresponding to the radii 𝑟1(at the heat source origin) and 𝑟2 and the +height 𝑏: +𝑞 = +1 +𝑎 +𝑏 +𝑐f +𝑐r +𝐹f +𝐹r +𝑛 +IFORM +P1 +P2 +P3 +P4 +P5 +P6 +P7 +P8 +2 + 𝑟1 +2 + 𝑟2 +2) +2𝑟2 +𝜋𝑏(𝑟1 +4 +𝑟1 +𝑟2 +𝑏1 +2 +𝑎 +𝑏 +𝑐f +𝑐r +𝐹f +𝐹r +3 +𝑟1 +𝑟2 +𝑟3 +𝑏1 +𝑏2 +𝐹f +𝐹r +*BOUNDARY +Purpose: Define a surface for coupling with the USA code [DeRuntz 1993]. The +outward normal vectors should point into the fluid media. The coupling with USA +is operational in explicit transient and in implicit natural frequency analyses. +Card +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SSID +WETDRY NBEAM +Type +I +Default +none +I +0 +I +0 + VARIABLE +DESCRIPTION +SSID +Segment set ID, see *SET_SEGMENT +WETDRY +Wet surface flag: +EQ.0: Dry, no coupling for USA DAA analysis, or Internal fluid +coupling for USA CASE analysis +EQ.1: Wet, coupled with USA for DAA analysis, or External +fluid coupling for USA CASE analysis +The number of nodes touched by USA Surface-of-Revolution +(SOR) elements. It is not necessary that the LS-DYNA model has +beams where USA has beams (i.e., SOR elements), merely that the +LS-DYNA model has nodes to receive the forces that USA will +return. +NBEAM +Remarks: +The underwater shock analysis code is an optional module. To determine +availability contact sales@lstc.com. +The wet surface of 3 and 4-noded USA general boundary elements is defined in LS- +DYNA with a segment set of 4-noded surface segments, where the fourth node can +duplicate the third node to form a triangle. The segment normal vectors should be +directed into the USA fluid. If USA overlays are going to be used to reduce the size +of the DAA matrices, the user should nonetheless define the wet surface here as if no +overlay were being used. If Surface-of -Revolution elements (SORs) are being used +in USA, then NBEAM should be non-zero on one and only one card in this section. +The wet surface defined here can cover structural elements or acoustic fluid volume +elements, but it can not touch both types in one model. +When running a coupled problem with USA, the procedure requires an additional +input file of USA keyword instructions. These are described in a separate USA +manual. The name of this input file is identified on the command line with the +usa = flag: +where uin is the USA keyword instruction file. +LSDYNA.USA i=inf usa=uin +*BOUNDARY_ELEMENT_METHOD_OPTION +Available options include: +CONTROL +FLOW +NEIGHBOR +SYMMETRY +WAKE +Purpose: +incompressible fluid dynamics or fluid-structure interaction problems. + Define input parameters for boundary element method analysis of +The boundary element method (BEM) can be used to compute the steady state or +transient fluid flow about a rigid or deformable body. The theory which underlies the +method is restricted to inviscid, incompressible, +attached fluid flow. The method should not be used to analyze flows where shocks or +cavitation are present. +In practice the method can be successfully applied to a wider class of fluid flow +problems than the assumption of inviscid, incompressible, attached flow would imply. +Many flows of practical engineering significance have large Reynolds numbers (above 1 +million). For these flows the effects of fluid viscosity are small if the flow remains +attached, and the assumption of zero viscosity may not be a significant limitation. Flow +separation does not necessarily invalidate the analysis. If well-defined separation lines +exist on the body, then wakes can be attached to these separation lines and reasonable +results can be obtained. The Prandtl-Glauert rule can be used to correct for non-zero +Mach numbers in a gas, so the effects of aerodynamic compressibility can be correctly +modeled (as long as no shocks are present). +The BOUNDARY_ELEMENT_METHOD_FLOW card turns on the analysis, and is +mandatory. +*BOUNDARY_ELEMENT_METHOD_CONTROL +Purpose: Control the execution time of the boundary element method calculation. The +CONTROL option is used to control the execution time of the boundary element +method calculation, and the use of this option is strongly recommended. The BEM +calculations can easily dominate the total execution time of a LS-DYNA run unless the +parameters on this card (especially DTBEM and/or IUPBEM) are used appropriately. +DTBEM is used to increase the time increment between calls to the BEM routines. This +can usually be done with little loss in accuracy since the characteristic times of the +structural dynamics and the fluid flow can differ by several orders of magnitude. The +characteristic time of the structural dynamics in LS-DYNA is given by the size of the +smallest structural element divided by the speed of sound of its material. For a typical +problem this characteristic time might be equal to 1 microsecond. Since the fluid in the +boundary element method is assumed to be incompressible (infinite speed of sound), +the characteristic time of the fluid flow is given by the streamwise length of the smallest +surface in the flow divided by the fluid velocity. For a typical problem this +characteristic time might be equal to 10 milliseconds. For this example DTBEM might +be set to 1 millisecond with little loss of accuracy. Thus, for this example, the boundary +element method would be called only once for every 1000 LS-DYNA iterations, saving +an enormous amount of computer time. +IUPBEM is used to increase the number of times the BEM routines are called before the +matrix of influence coefficients is recomputed and factored (these are time-consuming +procedures). If the motion of the body is entirely rigid body motion there is no need to +ever recompute and factor the matrix of influence coefficients after initialization, and +the execution time of the BEM can be significantly reduced by setting IUPBEM to a very +large number. For situations where the structural deformations are modest an +intermediate value (e.g., 10) for IUPBEM can be used. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LWAKE +DTBEM +IUPBEM +FARBEM +Type +I +Default +50 +F +0. +I +F +100 +2.0 +Remark +1 +DESCRIPTION +Number of elements in the wake of lifting surfaces. Wakes must +be defined for all lifting surfaces. +Time increment between calls to the boundary element method. +The fluid pressures computed during the previous call to the +BEM will continue to be used for subsequent LS-DYNA iterations +until a time increment of DTBEM has elapsed. +The number of times the BEM routines are called before the +matrix of influence coefficients is recomputed and refactored. +Nondimensional boundary between near-field and far-field +calculation of influence coefficients. + VARIABLE +LWAKE +DTBEM +IUPBEM +FARBEM +Remarks: +1. Wakes convect with the free-stream velocity. The number of elements in the +wake should be set to provide a total wake length equal to 5-10 times the char- +acteristic streamwise length of the lifting surface to which the wake is attached. +Note that each wake element has a streamwise length equal to the magnitude of +the free stream velocity multiplied by the time increment between calls to the +boundary element method routines. This time increment is controlled by +DTBEM. +2. The most accurate results will be obtained with FARBEM set to 5 or more, while +values as low as 2 will provide slightly reduced accuracy with a 50% reduction +in the time required to compute the matrix of influence coefficients. +*BOUNDARY_ELEMENT_METHOD_FLOW +Purpose: Turn on the boundary element method calculation, specify the set of shells +which define the surface of the bodies of interest, and specify the onset flow. +The *BOUNDARY_ELEMENT_METHOD_FLOW card turns on the BEM calculation. +This card also identifies the shell elements which define the surfaces of the bodies of +interest, and the properties of the onset fluid flow. The onset flow can be zero for +bodies which move through a fluid which is initially at rest. + Card 1 +1 +Variable +SSID +Type +I +2 +VX +F +3 +VY +F +4 +VZ +F +5 +6 +7 +8 +RO +PSTATIC MACH +F +F +Default +none +none +none +none +none +0. +Remark +1 +2 +F +0. +3 + VARIABLE +SSID +DESCRIPTION +Shell set ID for the set of shell elements which define the surface +of the bodies of interest . The nodes of these +shells should be ordered so that the shell normals point into the +fluid. +VX, VY, VZ +x, y, and z components of the free-stream fluid velocity. +RO +Fluid density. +PSTATIC +Fluid static pressure. +MACH +Free-stream Mach number. +Remarks: +1. +It is recommended that the shell segments in the SSID set use the NULL +material . This will provide for the display of fluid pressures +in the post-processor. For triangular shells the 4th node number should be the +same as the 3rd node number. For fluid-structure interaction problems it is +recommended that the boundary element shells use the same nodes and be +coincident with the structural shell elements (or the outer face of solid ele- +ments) which define the surface of the body. This approach guarantees that the +boundary element segments will move with the surface of the body as it de- +forms. +2. A pressure of PSTATIC is applied uniformly to all segments in the segment set. +If the body of interest is hollow, then PSTATIC should be set to the free-stream +static pressure minus the pressure on the inside of the body. +3. The effects of subsonic compressibility on gas flows can be included using a +non-zero value for MACH. The pressures which arise from the fluid flow are +increased using the Prandtl-Glauert compressibility correction. MACH should +be set to zero for water or other liquid flows. +*BOUNDARY_ELEMENT_METHOD_NEIGHBOR +Purpose: Define the neighboring elements for a given boundary element segment. +The pressure at the surface of a body is determined by the gradient of the doublet +distribution on the surface . The “Neighbor Array” +is used to specify how the gradient is computed for each boundary element segment. +Ordinarily, the Neighbor Array is set up automatically by LS-DYNA, and no user input +is required. The NEIGHBOR option is provided for those circumstances when the user +desires to define this array manually. +Elements Cards. The next “*” card terminates the input. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NELEM +NABOR1 NABOR2 NABOR3 NABOR4 +Type +I +I +I +I +I +Default +none +none +none +none +none + VARIABLE +DESCRIPTION +NELEM +Element number. +NABOR1 +Neighbor for side 1 of NELEM. +NABOR2 +Neighbor for side 2 of NELEM. +NABOR3 +Neighbor for side 3 of NELEM. +NABOR4 +Neighbor for side 4 of NELEM. +Remarks: +Each boundary element has 4 sides (Figure 6-1). Side 1 connects the 1st and 2nd nodes, +side 2 connects the 2nd and 3rd nodes, etc. The 4th side is null for triangular elements. +node 4 +side 3 +node 3 +side 4 +node 1 +segment(j) +side 1 +side 2 +node 2 +Figure 6-1. Each segment has 4 sides. +For most elements the specification of neighbors is straightforward. For the typical case +a quadrilateral element is surrounded by 4 other elements, and the neighbor array is as +shown in Figure 6-2. +neighbor(3, j) +side 3 +neighbor(4, j) +side 4 +segment(j) +side 1 +side 2 +neighbor(2, j) +neighbor(1, j) +Figure 6-2. Typical neighbor specification. +There are several situations for which the user may desire to directly specify the +neighbor array for certain elements. For example, boundary element wakes result in +discontinuous doublet distributions, and neighbors which cross a wake should not be +used. Figure 6-3 illustrates a situation where a wake is attached to side 2 of segment j. +For this situation two options exist. If neighbor(2,j) is set to zero, then a linear +computation of the gradient in the side 2 to side 4 direction will be made using the +difference between the doublet strengths on segment j and segment neighbor(4,j). This +is the default setup used by LS-DYNA when no user input is provided. By specifying +neighbor(2,j) as a negative number a more accurate quadratic curve fit will be used to +compute the gradient. The curve fit will use segment j, segment neighbor(4,j), and +segment -neighbor(2,j); which is located on the opposite side of segment neighbor(4,j) as +segment j. +-neighbor(2, j) +neighbor(4, j) +side 3 +side 4 +segment(j) +side 1 +side 2 +Figure 6-3. If neighbor(2,j) is a negative number it is assumed to lie on the +opposite side of neighbor(4,j) as segment j. +Another possibility is that no neighbors at all are available in the side 2 to side 4 +direction. In this case both neighbor(2,j) and neighbor(4,j) can be set to zero, and the +gradient in that direction will be assumed to be zero. This option should be used with +caution, as the resulting fluid pressures will not be accurate for three-dimensional +flows. However, this option is occasionally useful where quasi-two dimensional results +are desired. All of the above options apply to the side 1 to side 3 direction in the +obvious ways. +For triangular boundary elements side 4 is null. Gradients in the side 2 to side 4 +direction can be computed as described above by setting neighbor(4,j) to zero for a +linear derivative computation (this is the default setup used by LS-DYNA when no user +input is provided) or to a negative number to use the segment on the other side of +neighbor(2,j) and a quadratic curve fit. There may also be another triangular segment +which can be used as neighbor(4,j) . +neighbor(4, j) +segment(j) +side 2 +Figure 6-4. Sometimes another triangular boundary element segment can be +used as neighbor (4,j). +The rules for computing the doublet gradient in the side 2 to side 4 direction can be +summarized as follows (the side 1 to side 3 case is similar): +NABOR2 +NABOR4 +Doublet Gradient Computation +GT.0 +GT.0 +Quadratic fit using elements j, +NABOR2, and NABOR4. +LT.0 +GT.0 +GT.0 +LT.0 +Quadratic fit using elements j, -NAB- +OR2, and NABOR4. -NABOR2 is +assumed to lie on the opposite side of +NABOR4 as segment j . +Quadratic fit using elements j, +NABOR2, and -NABOR4. -NABOR4 +is assumed to lie on the opposite side +of NABOR2 as segment j. +EQ.0 +GT.0 +GT.0 +EQ.0 +EQ.0 +EQ.0 +Linear fit using elements j and +NABOR4. +Linear fit using elements j and +NABOR2. +Zero gradient. +Table 3.1 Surface pressure computation for element j. +*BOUNDARY_ELEMENT_METHOD_SYMMETRY +Purpose: To define a plane of symmetry for the boundary element method. The +SYMMETRY option can be used to reduce the time and memory required for symmetric +configurations. For these configurations the reduction in the number of boundary +elements by a factor of 2 will reduce the memory used by the boundary element method +by a factor of 4, and will reduce the computer time required to factor the matrix of +influence coefficients by a factor of 8. Only 1 plane of symmetry can be defined. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable BEMSYM +Type +Default +I +0 + VARIABLE +DESCRIPTION +BEMSYM +Defines symmetry plane for boundary element method. +EQ.0: no symmetry plane is defined +EQ.1: x = 0 is a symmetry plane +EQ.2: y = 0 is a symmetry plane +EQ.3: z = 0 is a symmetry plane +*BOUNDARY_ELEMENT_METHOD_WAKE +Purpose: To attach wakes to the trailing edges of lifting surfaces. Wakes should be +attached to boundary elements at the trailing edge of a lifting surface (such as a wing, +propeller blade, rudder, or diving plane). Wakes should also be attached to known +separation lines when detached flow is known to exist (such as the sharp leading edge +of a delta wing at high angles of attack). Wakes are required for the correct +computation of surface pressures for these situations. As described above, two +segments on opposite sides of a wake should never be used as neighbors. +Element Cards. (The next “*” card terminates the input.) + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NELEM +NSIDE +Type +I +I +Default +none +none +Remark +1 + VARIABLE +DESCRIPTION +NELEM +Element number to which a wake is attached. +NSIDE +The side of NELEM to which the wake is attached . +This should be the "downstream" side of NELEM. +Remarks: +1. Normally two elements meet at a trailing edge (one on the "upper" surface and +one on the "lower" surface). The wake can be attached to either element, but +not to both. +The *CASE command provides a way of running multiple LS-DYNA analyses (or cases) +sequentially by submitting a single input file. When *CASE commands are used to +define multiple cases, some portions of the input will be shared by some or all of the +cases and other portions will be unique to each case. Because the cases are run +sequentially, the results from one case, e.g., a dynain file, can be used in the analysis of +a different, subsequent case. Each case creates a unique set of output file names by +prepending “casen.” to the default file name, e.g., case101.d3plot, case102.glstat. +When the *CASE keyword appears in an input deck, it becomes necessary to append +the word “CASE” to the LS-DYNA execution line. For example, an SMP LS-DYNA +execution line might look something like +path_to_ls-dyna i=input.k ncpu=-4 CASE +An MPP LS-DYNA execution line might look something like +mpirun –np 4 path_to_mpp971 i=input.k CASE +*CASE_{OPTION} +Available options include: + +BEGIN_N +END_N +Purpose: Define a series of cases and perhaps subcases. The options *CASE_BEGIN_n +and *CASE_END_n appear in pairs and n is a numeric ID of a subcase. Subcase IDs +may be referenced by the *CASE command in defining a case. In other words, a case +may consist of one or more subcases. All keywords appearing between *CASE_BE- +GIN_n and *CASE_END_n comprise subcase n. If no *CASE command is defined, then +subcases defined by *CASE_BEGIN_n and *CASE_END_n then become cases. *CASE_- +BEGIN/*CASE_END can be nested, overlapped, and disjointed. Examples below +demonstrate the use of these options. +An alternative way of defining subcases is by appending the string “CID = n” to the end +of any keyword command. Any keyword so tagged will then be active only for those +cases that reference subcase n. There can be more than one space between the keyword +and “CID = n”. +Any keyword in the input deck not associated with a subcase is active for all cases. +GIN/*CASE_END. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CASEID +JOBID +Type +I +C +Default +none +none +Command Line Argument Cards. Command line cards set additional command line +arguments for the case CASEID . Include as many as needed, or as +few as none. Command line cards end when the first character of the next card is +numeric. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +Default +COMMANDS +A +Not Required +Subcase ID Cards. Define active subcase IDs for case CASEID . +These cards continue until the next keyword (“*”) card. + Card 3 +1 +2 +Variable +SCID1 +SCID2 +Type +I +I +3 +… +I +4 +… +I +5 +… +I +6 +… +I +7 +… +I +8 +… +I +Default +none +none +none +none +none +none +none +none + VARIABLE +DESCRIPTION +CASEID +Identification number for case. +VARIABLE +JOBID +DESCRIPTION +Optional string (no spaces) to be used as the jobid for this case. If +no JOBID is specified, the string CASEXX is used, where XX is +the CASEID in field 1 +*CASE +COMMANDS +Command line arguments. +SCIDn +Subcase ID active for case CASEID. +Remarks: +1. +2. +3. +If no *CASE keyword appears, subcases defined with *CASE_BEGIN/*CASE_- +END commands become cases and *CASE_BEGIN can optionally be followed +by extra command line arguments. +If no *CASE keyword appears, it is an error to append “CID = n” to any +keyword. +If multiple *CASE or *CASE_BEGIN keywords appear that have the same ID, +their command line arguments and active commands are merged. +4. The *CASE or *CASE_BEGIN keywords cannot be used within an include (*IN- +CLUDE) file. +Example 1: +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Define case 101 which includes subcase 1. +$ Define case 102 which includes subcase 4. +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +*CASE +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7 +$ CASEID + 101 JOBID_FOR_CASE101 +MEMORY=20M +1 +$ +*CASE +$ CASEID + 102 +MEMORY=20M NCYCLE=1845 +4 +$ +*TITLE CID=1 +THIS IS THE TITLE FOR CASE 101 +$ +*TITLE CID=4 +THIS IS THE TITLE FOR CASE 102 +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ Illustrate overlapping subcases. +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +*CASE_BEGIN_5 +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....> +*DATABASE_BINARY_D3THDT +1.e-5 +*CASE_BEGIN_3 +*DATABASE_NODOUT +1.e-5 +*CASE_END_5 +*DATABASE_ELOUT +1.e-5 +*CASE_END_3 +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +Example 2 above will generate d3thdt and nodout for CID = 5, and nodout and elout for +CID = 3. +*COMMENT +All input that falls between a *COMMENT command and the subsequent line of input +that has an asterisk in the first column thereby signaling the start of another keyword +command, is not acted on by LS-DYNA. This provides a convenient way to interject +multiple, successive lines of commentary anywhere inside an input deck. +*COMMENT also provides a convenient way to comment out an exisiting keyword +command and all its associated input data as shown in an example below. +Lines of input that are deactivated by *COMMENT are echoed on the screen and to the +messag and d3hsp files. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +Default +COMMENT +A +none + VARIABLE +DESCRIPTION +COMMENT +Any comment line. +Example: +In this excerpt from an input deck, 5 lines of comments including blank lines, are added +to the input deck. +*KEYWORD +*COMMENT +Units of this model are mks. +Input prepared by John Doe. +Input checked by Jane Doe. +*CONTROL_TERMINATION +1.E-02 +⋮ +*COMMENT +In this excerpt from an input deck, a contact is disabled by inserting *COMMENT +command before the contact keyword command. +⋮ +*COMMENT *CONTACT_AUTOMATIC_SURFACE_TO_SURFACE_ID +$# cid title + 1 +$# ssid msid sstyp mstyp sboxid mboxid spr mpr +1,2,0,3 +$# fs fd dc vc vdc penchk bt dt +0.2 +$# sfs sfm sst mst sfst sfmt fsf vsf +$# soft sofscl lcidab maxpar sbopt depth bsort frcfrq + 2 +*SET_SEGMENT +$# sid da1 da2 da3 da4 solver + 1 0.000 0.000 0.000 0.000MECH +$# n1 n2 n3 n4 a1 a2 a3 a4 + 2842 626 3232 3242 0.000 0.000 0.000 0.000 + 2846 2842 627 2843 0.000 0.000 0.000 0.000 +⋮ +The keyword *COMPONENT provides a way of incorporating specialized components +and features. The keyword control cards in this section are defined in alphabetical +order: +*COMPONENT_GEBOD_OPTION +*COMPONENT_GEBOD_JOINT_OPTION +*COMPONENT_HYBRIDIII +*COMPONENT_HYBRIDIII_JOINT_OPTION +*COMPONENT_GEBOD +Purpose: Generate a rigid body dummy based on dimensions and mass properties +from the GEBOD database. The motion of the dummy is governed by equations +integrated within LS-DYNA separately from the finite element model. Default joint +characteristics (stiffness’s, stop angles, etc.) are set internally and should give +reasonable results, however, they may be altered using the *COMPONENT_GEBOD_- +JOINT command. Contact between the segments of the dummy and the finite element +model is defined using the *CONTACT_GEBOD command. The use of a positioning +file is essential with this feature, see Appendix N for further details. +OPTION specifies the human subject type. The male and female types represent adults +while the child is genderless. +MALE +FEMALE +CHILD + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DID +UNITS +SIZE +Type +I +I +F +Default +none +none +none + Card 2 +Variable +1 +VX +Type +F +Default +0. +2 +VY +F +0. +3 +VZ +F +0. +4 +GX +F +0. +5 +GY +F +0. +6 +GZ +F +0. +7 +8 + VARIABLE +DESCRIPTION +DID +Dummy ID. A unique number must be specified. +VARIABLE +DESCRIPTION +UNITS +System of units used in the finite element model. +EQ.1: lbf × sec2/in - inch - sec +EQ.2: kg - meter - sec +EQ.3: kgf × sec2/mm - mm - sec +EQ.4: metric ton - mm - sec +EQ.5: kg - mm - msec +SIZE +Size of the dummy. This represents a combined height and +weight percentile ranging from 0 to 100 for the male and female +types. For the child the number of months of age is input with an +admissible range from 24 to 240. +VX, VY, VZ +Initial velocity of the dummy in the global x, y and z directions. +GX, GY, GZ +Global x, y, and z components of gravitational acceleration +applied to the dummy. +Example: +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *COMPONENT_GEBOD_MALE +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ A 50th percentile male dummy with the ID number of 7 is generated in the +$ lbf*sec^2-inch-sec system of units. The dummy is given an initial velocity of +$ 616 in/sec in the negative x direction and gravity acts in the negative z +$ direction with a value 386 in/sec^2. +$ +*COMPONENT_GEBOD_MALE +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ did units size + 7 1 50 +$ vx vy vz gx gy gz + -616 0 0 0 0 -386 +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +*COMPONENT_GEBOD_JOINT_OPTION +Purpose: Alter the joint characteristics of a GEBOD rigid body dummy. Setting a joint +parameter value to zero retains the default value set internally. See Appendix N for +further details. +The following options are available. +PELVIS +WAIST +LOWER_NECK +UPPER_NECK +LEFT_SHOULDER +RIGHT_SHOULDER +LEFT_ELBOW +RIGHT_ELBOW +LEFT_HIP +RIGHT_HIP +LEFT_KNEE +RIGHT_KNEE +LEFT_ANKLE +RIGHT_ANKLE + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DID +LC1 +LC2 +LC3 +SCF1 +SCF2 +SCF3 +Type +F +I +I +I +F +F +F + VARIABLE +DESCRIPTION +DID +LCi +SCFi +Dummy ID, see *COMPONENT_GEBOD_OPTION. +Load curve ID specifying the loading torque versus rotation (in +radians) for the ith degree of freedom of the joint. +Scale factor applied to the load curve of the ith joint degree of +freedom. +Card 2 +Variable +1 +C1 +Type +F +2 +C2 +F +3 +C3 +F +4 +5 +6 +7 +8 +NEUT1 +NEUT2 +NEUT3 +F +F +F + VARIABLE +DESCRIPTION +Ci +Linear viscous damping coefficient applied to the ith DOF of the +joint. Units are torque × time/radian, where the units of torque +and time depend on the choice of UNITS in card 1 of *COMPO- +NENT_GEBOD_OPTION. +NEUTi +Neutral angle (degrees) of joint's ith DOF. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LOSA1 +HISA1 +LOSA2 +HISA2 +LOSA3 +HISA3 +Type +F +F +F +F +F +F + VARIABLE +DESCRIPTION +LOSAi +HISAi +Value of the low stop angle (degrees) for the ith DOF of this joint. +Value of the high stop angle (degrees) for the ith DOF of this joint. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +UNK1 +UNK2 +UNK3 +Type +F +Default +0. +F +0. +F +0. +DESCRIPTION +Unloading stiffness (torque/radian) for the ith degree of freedom +of the joint. This must be a positive number. Units of torque +depend on the choice of UNITS in card 1 of *COMPONENT_GE- +BOD_OPTION. + VARIABLE +UNKi +Example 1: +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *COMPONENT_GEBOD_JOINT_LEFT_SHOULDER +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ The damping coefficients applied to all three degrees of freedom of the left +$ shoulder of dummy 7 are set to 2.5. All other characteristics of this joint +$ remain set to the default value. +$ +*COMPONENT_GEBOD_JOINT_LEFT_SHOULDER +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ did lc1 lc2 lc3 scf1 scf2 scf3 + 7 0 0 0 0 0 0 +$ c1 c2 c3 neut1 neut2 neut3 + 2.5 2.5 2.5 0 0 0 +$ losa1 hisa1 losa2 hisa2 losa3 hisa3 + 0 0 0 0 0 0 +$ unk1 unk2 unk3 + 0 0 0 +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +Example 2: +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *COMPONENT_GEBOD_JOINT_WAIST +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Load curve 8 gives the torque versus rotation relationship for the 2nd DOF +$ (lateral flexion) of the waist of dummy 7. Also, the high stop angle of the +$ 1st DOF (forward flexion) is set to 45 degrees. All other characteristics +$ of this joint remain set to the default value. +$ +*COMPONENT_GEBOD_JOINT_WAIST +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ did lc1 lc2 lc3 scf1 scf2 scf3 + 7 0 8 0 0 0 0 +$ c1 c2 c3 neut1 neut2 neut3 + 0 0 0 0 0 0 +$ losa1 hisa1 losa2 hisa2 losa3 hisa3 + 0 45 0 0 0 0 +$ unk1 unk2 unk3 + 0 0 0 +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +*COMPONENT_HYBRIDIII +Purpose: Define a HYBRID III dummy. The motion of the dummy is governed by +equations integrated within LS-DYNA separately from the finite element model. The +dummy interacts with the finite element structure through contact interfaces. Joint +characteristics (stiffnesses, damping, friction, etc.) are set internally and should give +reasonable results, however, they may be altered using the *COMPONENT_HYBRIDI- +II_JOINT command. Joint force and moments can be written to an ASCII file . + Card 1 +1 +2 +3 +4 +Variable +DID +SIZE +UNITS +DEFRM +Type +I +I +I +Default +none +none +none +I +1 +8 +5 +VX +F +0. +6 +VY +F +0. +7 +VZ +F +0. + VARIABLE +DESCRIPTION +DID +SIZE +Dummy ID. A unique number must be specified. +Size of dummy. +EQ.1: 5th percentile adult +EQ.2: 50th percentile adult +EQ.3: 95th percentile adult +NOTE: If negative then the best of currently available joint +properties are applied. +UNITS +System of units used in the finite element model. +EQ.1: lbf × sec2/in - inch - sec +EQ.2: kg - meter - sec +EQ.3: kgf × sec2/mm - mm - sec +EQ.4: metric ton - mm - sec +EQ.5: kg - mm - msec +VARIABLE +DESCRIPTION +DEFRM +Deformability type. +EQ.1: all dummy segments entirely rigid +EQ.2: deformable abdomen (low density foam, mat #57) +EQ.3: deformable jacket (low density foam, mat #57) +EQ.4: deformable headskin (viscoelastic, mat #6) +EQ.5: deformable abdomen/jacket +EQ.6: deformable jacket/headskin +EQ.7: deformable abdomen/headskin +EQ.8: deformable abdomen/jacket/headskin +VX, VY, VZ +Initial velocity of the dummy in the global x, y and z directions. + Card 2 +Variable +1 +HX +Type +F +Default +0. +2 +HY +F +0. +3 +HZ +F +0. +4 +RX +F +0. +5 +RY +F +0. +6 +RZ +F +0. +7 +8 + VARIABLE +DESCRIPTION +HX, HY, HZ +Initial global x, y, and z coordinate values of the H-point. +RX, RY, RZ +Initial rotation of dummy about the H-point with respect to the +global x, y, and z axes (degrees). +Example 1: +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *COMPONENT_HYBRIDIII +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ A 50th percentile adult rigid HYBRID III dummy with an ID number of 7 is defined +$ in the lbf*sec^2-inch-sec system of units. The dummy is assigned an initial +$ velocity of 616 in/sec in the negative x direction. The H-point is initially +$ situated at (x,y,z)=(38,20,0) and the dummy is rotated 18 degrees about the +$ global x-axis. +$ +*COMPONENT_HYBRIDIII +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ did . size units defrm vx vy vz + 7 2 1 1 -616. 0. 0. +$ hx hy hz rx ry rz + 38. 20. 0. 18. 0. 0. +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +*COMPONENT_HYBRIDIII_JOINT_OPTION +Purpose: Alter the joint characteristics of a HYBRID III dummy. Setting a joint +parameter value to zero retains the default value set internally. Joint force and +moments can be written to an ASCII file . Further details +pertaining to the joints are found in the Hybrid III Dummies section of Appendix N. +The following options are available: +LUMBAR +RIGHT_ELBOW +RIGHT_KNEE +LOWER_NECK +LEFT_WRIST +LEFT_ANKLE +UPPER_NECK +RIGHT_WRIST +RIGHT_ANKLE +LEFT_SHOULDER +LEFT_HIP +STERNUM +RIGHT_SHOULDER +RIGHT_HIP +LEFT_KNEE_SLIDER +LEFT_ELBOW +LEFT_KNEE +RIGHT_KNEE_SLIDER + Card 1 +1 +Variable +DID +Type +F + Card 2 +Variable +1 +C1 +2 +Q1 +F +2 +3 +Q2 +F +3 +4 +Q3 +F +4 +5 +6 +7 +8 +FRIC +F +5 +6 +7 +8 +ALO1 +BLO1 +AHI1 +BHI1 +QLO1 +QHI1 +SCLK1 +Type +F +F +F +F +F +F +F +F +Leave blank if joint has only one degree of freedom. + Card 3 +Variable +1 +C2 +2 +3 +4 +5 +6 +7 +8 +ALO2 +BLO2 +AHI2 +BHI2 +QLO2 +QHI2 +SCLK2 +Type +F +F +F +F +F +F +F +Leave blank if the joint has only two degrees of freedom. + Card 4 +Variable +1 +C3 +2 +3 +4 +5 +6 +7 +8 +ALO3 +BLO3 +AHI3 +BHI3 +QLO3 +QHI3 +SCLK3 +Type +F +F +F +F +F +F +F +F + VARIABLE +DESCRIPTION +Dummy ID, see *COMPONENT_HYBRIDIII +Initial value of the joint's ith degree of freedom. Units of degrees +are defined for rotational DOF. See Appendix N for a listing of +the applicable DOF. +Friction load on the joint. +Linear viscous damping coefficient applied to the ith DOF of the +joint. +Linear coefficient for the low regime spring of the joint's ith DOF. +Cubic coefficient for the low regime spring of the joint's ith DOF. +Linear coefficient for the high regime spring of the joint's ith DOF. +Cubic coefficient for the high regime spring of the joint's ith DOF. +Value at which the low regime spring definition becomes active. +Value at which the high regime spring definition becomes active. +Scale value applied to the stiffness of the +(default = 1.0). +joint's ith DOF +DID +Qi +FRIC +Ci +ALOi +BLOi +AHIi +BHIi +QLOi +QHIi +SCLKi +Example: +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *COMPONENT_HYBRIDIII_JOINT_LEFT_ANKLE +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ The damping coefficients applied to all three degrees of freedom of the left +$ ankle of dummy 7 are set to 2.5. All other characteristics of this joint +$ remain set to the default value. The dorsi-plantar flexion angle is set to +$ 20 degrees. +$ +*COMPONENT_HYBRIDIII_JOINT_LEFT_ANKLE +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ did q1 q2 q3 fric + 7 0 20. 0 0 0 +$ c1 alo1 blo1 ahi1 bhi1 qlo1 qhi1 + 2.5 0 0 0 0 0 0 +$ c2 alo2 blo2 ahi2 bhi2 qlo2 qhi2 + 2.5 0 0 0 0 0 0 +$ 2.5 alo3 blo3 ahi3 bhi3 qlo3 qhi3 +The keyword *CONSTRAINED provides a way of constraining degrees of freedom to +move together in some way. The keyword cards in this section are defined in +alphabetical order: +*CONSTRAINED_ADAPTIVITY +*CONSTRAINED_BEAM_IN_SOLID +*CONSTRAINED_BUTT_WELD +*CONSTRAINED_COORDINATE_{OPTION} +*CONSTRAINED_EULER_IN_EULER +*CONSTRAINED_EXTRA_NODES_OPTION +*CONSTRAINED_GENERALIZED_WELD_OPTION_{OPTION} +*CONSTRAINED_GLOBAL +*CONSTRAINED_INTERPOLATION_{OPTION} +*CONSTRAINED_INTERPOLATION_SPOTWELD +*CONSTRAINED_JOINT_OPTION_{OPTION}_{OPTION}_{OPTION} +*CONSTRAINED_JOINT_COOR_OPTION_{OPTION}_{OPTION}_{OPTION} +*CONSTRAINED_JOINT_STIFFNESS_OPTION +*CONSTRAINED_JOINT_USER_FORCE +*CONSTRAINED_LAGRANGE_IN_SOLID +*CONSTRAINED_LINEAR_GLOBAL +*CONSTRAINED_LINEAR_LOCAL +*CONSTRAINED_LOCAL +*CONSTRAINED_MULTIPLE_GLOBAL +*CONSTRAINED_NODAL_RIGID_BODY_{OPTION}_{OPTION} +*CONSTRAINED_NODE_INTERPOLATION +*CONSTRAINED_NODE_TO_NURBS_PATCH +*CONSTRAINED_POINTS +*CONSTRAINED_RIGID_BODIES +*CONSTRAINED_RIGID_BODY_INSERT +*CONSTRAINED_RIGID_BODY_STOPPERS +*CONSTRAINED_RIVET_{OPTION} +*CONSTRAINED_SHELL_TO_SOLID +*CONSTRAINED_SPLINE +*CONSTRAINED_SPOTWELD_{OPTION}_{OPTION} +*CONSTRAINED_SPR2 +*CONSTRAINED_TIEBREAK +*CONSTRAINED_TIED_NODES_FAILURE +*CONSTRAINED_ADAPTIVITY +Purpose: Constrains a node to the midpoint along an edge of an element. This +keyword is automatically created by LS-DYNA during an h-adaptive simulation +involving 3-D shells. + Card 1 +Variable +1 +SN +2 +3 +4 +5 +6 +7 +8 +MN1 +MN2 +Type +I +I +I +Default +none +none +none + VARIABLE +DESCRIPTION +SN +MN1 +MN2 +Slave node. This is the node constrained at the midpoint of an +edge of an element. +The node at one end of an element edge. +The node at the other end of that same element edge. +*CONSTRAINED_BEAM_IN_SOLID_{OPTION} +Available options include: + +ID +TITLE +Purpose: This keyword constrains beam structures to move with Lagrangian +solids/thick shells, which serve as the master component. This keyword constrains +both acceleration and velocity. This feature is intended to sidestep certain limitations in +the CTYPE = 2 implementation in *CONSTRAINED_LAGRANGE_IN_SOLID. Notable +features of this keyword include: +1. CDIR = 1 feature. With the CDIR = 1 option coupling occurs only in the +normal directions. This coupling allows for releasing the constraints along +beam axial direction. +2. Axial coupling force. Debonding processes can be modeled with a user +defined function or user provided subroutine giving the axial shear force based +on the slip between rebar nodes and concrete solid elements. This feature is +invoked by setting AXFOR flag to a negative integer which refers to the *DE- +FINE_FUNCTION ID or a number greater than 1000. In the latter case, first we +need to modify the subroutine rebar_bondslip_get_getforce() in dyn21.F to add +in one or more debonding laws; each tagged with a “lawid”. Then we could +specify which debonding law to use with the AXFOR flag. AXFOR value great- +er than 1000 will call the user subroutine and pass AXFOR in as “lawid”. CDIR +has to be set to 1 in this case to release the axial constraints. +3. NCOUP feature. Coupling not only at nodes, but also at multiple coupling +points in between the two beam element nodes. Please note, the previous im- +plementation done in *CONSTRAINED_LAGRANGE_IN_SOLID CTYPE 2 +causes errors in energy balance. +4. Tetrahedral and pentahedra solid elements are supported. They are treated +as degenerated hexahedra in CTYPE2 implementation. +5. Velocity/Fixed boundary condition. The CTYPE 2 implementation failed to +constrain beam nodes that were buried inside elements whose nodes had veloc- +ity/fixed boundary conditions prescribed. +6. Optimized Sorting. Sorting subroutine is optimized for larger problems to +achieve better performance and less memory usage. +If a title is not defined, LS-DYNA will automatically create an internal title for this +coupling definition. +Title Card. Additional card for TITLE and ID keyword options. +Title +1 +2 +3 +4 +5 +6 +7 +8 +Variable +COUPID +Type +I +TITLE +A70 + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SLAVE MASTER +SSTYP +MSTYP +NCOUP +CDIR +I +0 +7 +I +0 +8 +5 +6 +Type +I +I +Default +none +none + Card 2 +1 +2 +I +0 +3 +I +0 +4 +Variable +START +END +AXFOR +Type +Default +F +0 +F +1010 +I +0 + VARIABLE +COUPID +DESCRIPTION +Coupling (card) ID number (I10). If not defined, LS-DYNA will +assign an internal coupling ID based on the order of appearance +in the input deck. +TITLE +A description of this coupling definition. +SLAVE +Slave set ID defining a part, part set ID of the Lagrangian beam +structure . +VARIABLE +MASTER +DESCRIPTION +Master set ID defining a part or part set ID of the Lagrangian +solid elements or thick shell elements . +SSTYP +Slave set type of “SLAVE”: +EQ.0: part set ID (PSID). +EQ.1: part ID (PID). +MSTYP +Master set type of “MASTER”: +EQ.0: part set ID (PSID). +EQ.1: part ID (PID). +NCOUP +Number of coupling points generated in one beam element. If set +to 0, coupling only happens at beam nodes. Otherwise, coupling +is done at both the beam nodes and those automatically generated +coupling points. +CDIR +Coupling direction. +EQ.0: default, constraint applied along all directions. +EQ.1: Constraint only applied along normal directions; along +the beam axial direction there is no constraint. +START +Start time for coupling. +END +End time for coupling. +AXFOR +ID of a user defined function describes coupling force versus slip +along beam axial direction. +GE.0: +EQ.-n: +OFF +n is the function ID in *DEFINE_FUNCTION +EQ.n > 1000: +n is the debonding law id “lawid” in user +defined subroutine rebar_bondslip_get_force(). +Example: +1. The example below shows how to define a function and use it to prescribe the +debonding process. User can define his own function based on different debonding +theories. +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|... +.8 +*CONSTRAINED_BEAM_IN_SOLID +$# slave master sstyp mstyp ctype empty nquad +idir + 2 1 1 1 0 2 +1 +$# start end axfor + 0.000 0.000 -10 +*DEFINE_FUNCTION + 10 +float force(float slip,float leng) +{ +float force,pi,d,area,shear,pf; +pi = 3.1415926; +d = 0.175; +area = pi*d*leng; +pf = 1.0; +if (slip < 0.25) { +shear = slip*pf; +} else { +shear = 0.25*pf; +} +force = shear*area; +return force; +} +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|... +.8 +2. The example below shows how to define a user subroutine and use it to prescribe the +debonding process. +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|... +.8 +*CONSTRAINED_BEAM_IN_SOLID +$# slave master sstyp mstyp ctype empty nquad +idir + 2 1 1 1 0 2 +1 +$# start end axfor + 0.000 0.000 1001 +*CONSTRAINED_BEAM_IN_SOLID +$# slave master sstyp mstyp ctype empty nquad +idir + 3 1 1 1 0 2 +1 +$# start end axfor + 0.000 0.000 1002 +*USER_LOADING +$ parm1 parm2 parm3 parm4 parm5 parm6 parm7 +parm8 + 1.0 6.0 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|... +.8 +And the user debonding law subroutine: + subroutine rebar_bondslip_get_force(slip,dl,force,hsv, +. userparm,lawid) + real hsv + dimension hsv(12),cm(8),userparm(*) +c +c in this subroutine user defines debonding properties and +c call his own debonding subroutine to get force + cm(1)=userparm(1) + cm(2)=userparm(2) + cm(3)=2.4*(cm(2)/5.0)**0.75 + cm(8)=0. +c + pi = 3.1415926 + d = 0.175 + area = pi*0.25*d*d*dl + pf = 1.0 +c + if (lawid.eq.1001) then + if (slip.lt.0.25) then + shear = slip*pf + else + shear = 0.25*pf + endif + force = sign(1.0,slip)*shear*area + elseif (lawid.eq.1002) then + if (slip.lt.0.125) then + shear = slip*pf + else + shear = 0.125*pf + endif + endif + return + end +*CONSTRAINED_BUTT_WELD +Purpose: Define a line of coincident nodes that represent a structural butt weld +between two parts defined by shell elements. Failure is based on nodal plastic strain for +ductile failure and stress resultants for brittle failure. This input is much simpler than +the alternative approach for defining butt welds, see *CONSTRAINED_GENERAL- +IZED_WELD_BUTT. The local coordinate system, the effective length, and thickness +for each pair of butt welded nodes are determined automatically in the definition +below. In the GENERALIZED option these quantities must be defined in the input. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SNSID +MNSID +EPPF +SIGF +BETA +Type +I +I +F +F +F +Default +none +none +0. +1.e+16 +1.0 +Remarks +1, 2 +3, 4 +3 +3 + VARIABLE +DESCRIPTION +SNSID +Slave node set ID, see *SET_NODE_OPTION. +MNSID +Master node set ID, see *SET_NODE_OPTION. +EPPF +SIGF +Plastic strain at failure +𝜎𝑓 , stress at failure for brittle failure. +BETA +𝛽, failure parameter for brittle failure. +Remarks: +1. Nodes in the master and slave sets must be given in the order they appear as +one moves along the edge of the surface. An equal number of coincident nodes +must be defined in each set. In a line weld the first and last node in a string of +nodes can be repeated in the two sets. If the first and last pair of nodal points +are identical, a circular or closed loop butt weld is assumed. See Figure 10-1, +where the line butt weld and closed loop weld are illustrated. +local y-axis +Length of +butt weld +Repeated nodal point +may start or end a butt +weld line. This beginning +or ending nodal point +must exist in both and +slave and master definitions +Two coincident butt welded +nodal points. +Repeated nodal point +pair must start and end +circular butt weld. Any +nodal pair in the circle +can be used. +Figure 10-1. Definition of butt welds are shown above. The butt weld can be +represented by a line of nodal points or by a closed loop +2. Butt welds may not cross. For complicated welds, this option can be combined +with the input in *CONSTRAINED_GENERALIZED_WELD_BUTT to handle +the case where crossing occurs. Nodes in a butt weld must not be members of +rigid bodies. +3. +If the average volume-weighted effective plastic strain in the shell elements +adjacent to a node exceeds the specified plastic strain at failure, the node is +released. Brittle failure of the butt welds occurs when: +𝛽√𝜎𝑛 +2 + 3(𝜏𝑛 +2 + 𝜏𝑡 +2) ≥ 𝜎𝑓 +where, +𝜎𝑛 = normal stress (local x) +𝜏𝑛 = shear stress in direction of weld (local y) +𝜏𝑡 = shear stress normal to weld (local z) +𝜎𝑓 = failure stress +𝛽 = failure parameter +The component σn is nonzero for tensile values only. The nodes defining the +slave and master sides of the butt weld must coincide. The local z-axis at a +master node is normal to the master side plane of the butt weld at the node, and +the local y-axis is taken as the vector in the direction of a line connecting the +mid-points of the line segments lying on either side of the master node. The +normal vector is found by summing the unit normal vectors of all shell ele- +ments on the master side sharing the butt welded node. The direction of the +normal vector at the node is chosen so that the x-local vector points towards the +elements on the slave side in order to identify tensile versus compressive +stresses. The thickness of the butt weld and length of the butt weld are needed +to compute the stress values. The thickness is based on the average thickness of +the shell elements that share the butt welded nodal pair, and the chosen length +of the butt weld is shown in Figure 10-1. +4. Butt welds may be used to simulate the effect of failure along a predetermined +line, such as a seam or structural joint. When the failure criterion is reached at a +nodal pair, the nodes begin to separate. As this effect propagates, the weld will +appear to “unzip,” thus simulating failure of the connection. +*CONSTRAINED_COORDINATE_{OPTION} +To define constraints based on position coordinates the following options are available: + +LOCAL +Purpose: The keyword is developed to allow the definition of constraints in position +coordinates in springback simulation. With the frequent application of adaptive mesh +in stamping simulation, nodes needed for springback constraints are often unavailable +until the last process simulation before springback is complete. On the other hand, if +the nodes are available, their positions may not be exactly on the desired locations +required for springback constraints. With this new keyword, the springback simulation +is no longer dependent on the previous process simulation results and the exact +springback constraint locations can be specified. + Card 1 +Variable +1 +ID +2 +3 +PID +IDIR +Type +I +I +I +4 +X1 +F +5 +Y1 +F +6 +Z1 +F +Default +none +none +none +0.0 +0.0 +0.0 +8 +7 +CID +I +0 + VARIABLE +DESCRIPTION +ID +PID +IDIR +Identification number of a constraint. +Part ID of the part to be constrained. +Applicable degrees-of-freedom being constrained: +EQ.1: x translational degree-of-freedom, +EQ.2: y translational degree-of-freedom, +EQ.3: z translational degree-of-freedom. +X1, Y1, Z1 +X, Y, Z coordinates of the location being constrained. +CID +Local coordinate system ID. +Figure 10-2. Constrained locations of a trim panel (NUMISHEET 2005 cross +member). +General remarks: +The identification number of a constraint must be unique; in particular, the IDs must be +unique even for two constraints involving the same X, Y, Z coordinates but different +degrees of freedom. When the LOCAL option is invoked, a local coordinate system ID, +as defined with *DEFINE_COORDINATE_{OPTION} keyword, should be provided in +the CID field. +Defining constraints using coordinates can now be done in Springback process of LS- +PrePost4.0 eZSetup for metal forming application, using the Pick location button (http://- +ftp.lstc.com/anonymous/outgoing/lsprepost/4.0/metalforming/). +Application example: +An example of using the keyword is listed below. A part with PID 18 is constrained in +6 locations in a local coordinate system ID 9, defined by the keyword *DEFINE_COOR- +DINATE_SYSTEM. Constrained DOFs are indicated by IDIR. +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*CONSTRAINED_COORDINATE +$ ID IDPT IDIR x y z CID + 1 18 2 -555.128 86.6 1072.29 9 + 2 18 3 -555.128 86.6 1072.29 9 + 3 18 3 -580.334 -62.15 1068.32 9 + 4 18 1 568.881 81.2945 1033.72 9 + 5 18 2 568.881 81.2945 1033.72 9 + 6 18 3 568.881 81.2945 1033.74 9 +) +( +- +) +( +- +150 +100 +50 +-50 +-100 +SPC Force @ Nodes + A + B + C + D + E + F + G + H + I + J +0.2 +0.4 +0.6 +0.8 +Time (Sec.) +Figure 10-3. SPC Z-forces at 10 nodes. +140 +120 +100 +80 +60 +40 +20 +SPC Force @ Nodes + Sum SPC force 10 nodes +0.2 +0.4 +0.6 +0.8 +Time (Sec.) +Figure 10-4. SPC Z-force summation of the 10 nodes +*DEFINE_COORDINATE_SYSTEM +$ CID X0 Y0 Z0 XL YL ZL + 9 0.0 0.0 0.0 0.0 10.0 0.0 +$ XP YP ZP + 10.0 10.0 0.0 +It is possible to output SPC forces on the coordinates constrained. For each position +coordinate set, an extra node will be generated and SPC forces are calculated and +output to SPCFORC file. The frequency of the output is specified with the keyword +*DATABASE_SPCFORC. Shown in the Figure 10-2 are the Z-constrained locations on +the trimmed panel (half with symmetric conditions at the smaller end) of the +NUMISHEET 2005 cross member. SPC forces in Z direction of these 10 locations were +recovered after a multi-steps static implicit springback with this over-constrained +boundary condition, Figure 10-3. The summation of these Z-forces is shown in Figure +10-4 and it approaches to zero as the residual stresses are balanced out by the +springback shape, absent of gravity. +Revision information: +This feature is now available in LS-DYNA R5 Revision 52619 or later releases. The SPC +output feature is available in LS-DYNA Revision 62560 and later releases, both in SMP +and MPP. +*CONSTRAINED_EULER_IN_EULER +Purpose: This command defines the coupling interaction between EULERIAN +materials in two overlapping, geometrically similar, multi-material Eulerian mesh sets. +The command allows a frictionless “contact” between two or more different Eulerian +materials. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PSIDSLV PSIDMST +PFAC +Type +Default +I +0 +I +0 +F +0.1 + VARIABLE +DESCRIPTION +PSIDSLV +Part set ID of the 1st ALE or Eulerian set of mesh(es) (slave). +PSIDMST +Part set ID of the 2nd ALE or Eulerian set of mesh(es) (master). +PFAC +A penalty factor for the coupling interaction between the two +PSIDs. +Remarks: +1. The 2 meshes must be of Eulerian formulation (the meshes are fixed in space, +not moving). Consider 2 overlapping Eulerian meshes. Each Eulerian mesh +contains 2 physical materials, say a vacuum and a metal. This card provides a +frictionless “contact” or interaction between the 2 metals, each resides in a dif- +ferent Eulerian mesh system. Due to its restrictive nature, this option is cur- +rently only an experimental feature. +2. Contact pressure is built up in two overlapping Eulerian elements if their +combined material fill fraction exceeds 1.0 (penalty formulation). +3. This feature needs to be combined with *MAT_VACUUM (element formula- +tion 11). +Example: +Consider an ALE/Eulerian multi-material model (ELFORM = 11) consisting of: +PID 1 = *MAT_NULL (material 1) +PID 2 = *MAT_VACUUM ⇒ PID 1 is merged at its boundary to PID 2. +PID 3 = *MAT_NULL (material 3) +PID 4 = *MAT_VACUUM ⇒ PID 3 is merged at its boundary to PID 4. +The mesh set containing PID 1 & 2 intersects or overlaps with the mesh set containing +PID 3 & 4. PID 1 is given an initial velocity in the positive x direction. This will cause +material 1 to contact material 3 (note that materials 2 & 4 are void). The interaction +between materials 1 & 3 is possible by defining this coupling command. In this case +material 1 can flow within the mesh region of PID 1 & 2 only, and material 3 can flow +within the mesh region of PID 3 & 4 only. +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|...8 +*ALE_MULTI-MATERIAL_GROUP +$ SID SIDYTPE + 1 1 + 2 1 + 3 1 + 4 1 +*CONSTRAINED_EULER_IN_EULER +$ PSID1 PSID2 PENAL + 11 12 0.1 +*SET_PART_LIST + 11 + 1 2 +*SET_PART_LIST + 12 + 3 4 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|...8 +*CONSTRAINED_EXTRA_NODES_OPTION +Available options include: +NODE +SET +Purpose: Define extra nodes for rigid body. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID +NID/NSID +IFLAG +Type +I +I +Default +none +none +I +0 + VARIABLE +PID +DESCRIPTION +Part ID of rigid body to which the nodes will be added, see +*PART. +NID / NSID +Node (keyword option: NODE) or node set ID (keyword option: +SET), see *SET_NODE, of added nodes. +This flag is meaningful if and only if the inertia properties of the +Part ID are defined in PART_INERTIA. If set to unity, the center- +of-gravity, the translational mass, and the inertia matrix of the +PID will be updated to reflect the merged nodal masses of the +node or node set. If IFLAG is defaulted to zero, the merged +nodes will not affect the properties defined in PART_INERTIA +since it is assumed the properties already account for merged +nodes. +IFLAG +Remarks: +Extra nodes for rigid bodies may be placed anywhere, even outside the body, and they +are assumed to be part of the rigid body. They have many uses including: +1. The definition of draw beads in metal forming applications by listing nodes +along the draw bead. +2. Placing nodes where joints will be attached between rigid bodies. +3. Defining a node where point loads are to be applied or where springs may be +attached. +4. Defining a lumped mass at a particular location. +The coordinates of the extra nodes are updated according to the rigid body motion. +Examples: +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *CONSTRAINED_EXTRA_NODES_NODE +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Rigidly attach nodes 285 and 4576 to part 14. (Part 14 MUST be a rigid body.) +$ +*CONSTRAINED_EXTRA_NODES_NODE +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ pid nid + 14 285 + 14 4576 +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *CONSTRAINED_EXTRA_NODES_SET +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Rigidly attach all nodes in set 4 to part 17. (Part 17 MUST be a rigid body.) +$ +$ In this example, four nodes from a deformable body are attached +$ to rigid body 17 as a means of joining the two parts. +$ +*CONSTRAINED_EXTRA_NODES_SET +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ pid nsid + 17 4 +$ +$ +*SET_NODE_LIST +$ sid + 4 +$ nid1 nid2 nid3 nid4 nid5 nid6 nid7 nid8 + 665 778 896 827 +$ +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +*CONSTRAINED_GENERALIZED_WELD_OPTION_{OPTION} +Available options include: +SPOT +FILLET +BUTT +CROSS_FILLET +COMBINED +To define an ID for the weld use the option: +ID +Purpose: Define spot, fillet, butt, and other types of welds. Coincident nodes are +permitted if the local coordinate ID is defined. For the spot weld a local coordinate ID +is not required if the nodes are offset. Failures can include both the plastic and brittle +failures. These can be used either independently or together. Failure occurs when +either criteria is met. The welds may undergo large rotations since the equations of +rigid body mechanics are used to update their motion. Weld constraints between solid +element nodes are not supported. +ID Card. Additional card for ID keyword option. + ID Card +1 +2 +3 +4 +5 +6 +7 +8 +Variable +WID +Type +Default +I +Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NSID +CID +FILTER WINDOW +NPR +NPRT +Type +I +I +I +E +I +I +Default +none +none + VARIABLE +DESCRIPTION +WID +NSID +CID +FILTER +WINDOW +Optional weld ID. +Nodal set ID, see *SET_NODE_OPTION. +Coordinate system ID for output of spot weld data to SWFORC in +local system, see *DEFINE_COORDINATE_OPTION. CID is not +required for spot welds if the nodes are not coincident. +Number of force vectors saved for filtering. This option can +eliminate spurious failures due to numerical force spikes; +however, memory requirements are significant since 6 force +components are stored with each vector. +LE.1: no filtering +GE.2: simple average of force components divided by FILTER +or the maximum number of force vectors that are stored +for the time window option below. +Time window for filtering. This option requires the specification +of the maximum number of steps which can occur within the +filtering time window. If the time step decreases too far, then the +filtering time window will be ignored and the simple average is +used. +EQ.0: time window is not used +NPR +Number of individual nodal pairs in the cross fillet or combined +general weld. +VARIABLE +DESCRIPTION +NPRT +Print option in file rbdout. +EQ.0: default from the control card, *CONTROL_OUTPUT, is +used, see variable name IPRTF. +EQ.1: data is printed +EQ.2: data is not printed +Spot Weld Card. Additional Card required SPOT keyword option. + Card 2 +1 +2 +Variable +TFAIL +EPSF +Type +F +F +3 +SN +F +4 +SS +F +5 +N +F +6 +M +F +7 +8 + VARIABLE +DESCRIPTION +TFAIL +Failure time for constraint set, tf . (default = 1.E+20) +Effective plastic strain at failure, 𝜖fail +𝑝 defines ductile failure. +Sn, normal force at failure, only for the brittle failure of spot +welds. +Ss, shear force at failure, only for the brittle failure of spot welds. +n, exponent for normal force, only for the brittle failure of spot +welds. +m, exponent for shear force, only for the brittle failure of spot +welds. +EPSF +SN +SS +N +M +Remarks: +Spot weld failure due to plastic straining occurs when the effective nodal plastic strain +𝑝 . This option can model the tearing out of a spot weld from +exceeds the input value, 𝜀fail +the sheet metal since the plasticity is in the material that surrounds the spot weld, not +the spot weld itself. A least squares algorithm is used to generate the nodal values of +plastic strains at the nodes from the element integration point values. The plastic strain +is integrated through the element and the average value is projected to the nodes via a +node 3 +node 2 +node 1 +node 2 +node 1 +2 NODE SPOTWELD +xx +node N +node N - 1 +N NODE SPOTWELD +node 2 +node 1 +Figure 10-5. Nodal ordering and orientation of the local coordinate system is +important for determining spotweld failure. +least square fit. This option should only be used for the material models related to +metallic plasticity and can result in slightly increased run times. +Brittle failure of the spot welds occurs when: +[ +max(𝑓𝑛, 0) +𝑆𝑛 +] ++ [ +∣𝑓𝑠∣ +𝑆𝑠 +] +≥ 1 +where fn and fs are the normal and shear interface force. Component fn contributes for +tensile values only. When the failure time, tf, is reached the nodal rigid body becomes +inactive and the constrained nodes may move freely. In Figure 10-5 the ordering of the +nodes is shown for the 2 node and 3 node spot welds. This order is with respect to the +local coordinate system where the local z-axis determines the tensile direction. The +nodes in the spot weld may coincide. The failure of the 3 node spot weld may occur +gradually with first one node failing and later the second node may fail. For n noded +spot welds the failure is progressive starting with the outer nodes (1 and n) and then +moving inward to nodes 2 and n - 1. Progressive failure is necessary to preclude +failures that would create new rigid bodies. +Fillet Weld Card. Additional Card required for the FILLET keyword option. + Card 2 +1 +2 +3 +4 +Variable +TFAIL +EPSF +SIGF +BETA +Type +F +F +F +F +5 +L +F +6 +W +F +7 +A +F +8 +ALPHA +F + VARIABLE +DESCRIPTION +TFAIL +Failure time for constraint set, tf (default = 1.E+20). +EPSF +SIGF +Effective plastic strain at failure, 𝜖fail +𝑝 defines ductile failure. +𝜎𝑓 , stress at failure for brittle failure. +BETA +𝛽, failure parameter for brittle failure. +L +W +A +L, length of fillet weld . +w, separation of parallel fillet welds . +a, fillet weld throat dimension . +ALPHA +𝛼, weld angle in degrees. +Remarks: +Ductile fillet weld failure, due to plastic straining, is treated identically to spot weld +failure. Brittle failure occurs when the following weld stress condition is met on the +narrowest fillet weld cross section (across the throat): +𝛽√𝜎𝑛 +2 + 3(𝜏𝑛 +2 + 𝜏𝑡 +2) ≥ 𝜎𝑓 +Where +𝜎𝑛 = normal stress +𝜏𝑛 = shear stress in local z-x plane +𝜏𝑡 = 𝑠hear stress in local-y direction +2 Node Fillet Weld +local coordinate +system +3 Node Fillet Weld +Figure 10-6. Nodal ordering and orientation of the local coordinate system is +shown for fillet weld failure. The angle is defined in degrees. +𝜎𝑓 = failure stress +𝛽 = failure parameter +The component 𝜎𝑛 is nonzero for tensile values only. When the failure time, 𝑡𝑓 , is +reached the nodal rigid body becomes inactive and the constrained nodes may move +freely. In Figure 10-6 the ordering of the nodes is shown for the 2 node and 3 node fillet +welds. This order is with respect to the local coordinate system where the local z axis +determines the tensile direction. The initial orientation of the local coordinate system is +defined by CID. If CID = 0 then the global coordinate system is used. The local +coordinate system is updated according to the rotation of the rigid body representing +the weld. The failure of the 3 node fillet weld may occur gradually with first one node +failing and later the second node may fail. +LL +11 +22 +11 +22 +22 +11 +22 +11 +22 +11 +22 +11 +22 +11 +22 +2 tied nodes that can +be coincident +Figure 10-7. Orientation of the local coordinate system and nodal ordering is +shown for butt weld failure. +Butt Weld Card. Additional Card required for the BUTT keyword option. + Card 2 +1 +2 +3 +4 +Variable +TFAIL +EPSF +SIGY +BETA +Type +F +F +F +F +5 +L +F +6 +D +F +8 + VARIABLE +DESCRIPTION +TFAIL +Failure time for constraint set, tf . (default = 1.E+20) +EPSF +SIGY +Effective plastic strain at failure, 𝜖fail +𝑝 defines ductile failure. +𝜎𝑓 , stress at failure for brittle failure. +BETA +𝛽, failure parameter for brittle failure. +L, length of butt weld . +d, thickness of butt weld . +L +D +Remarks: +Ductile butt weld failure, due to plastic straining, is treated identically to spot weld +failure. Brittle failure of the butt welds occurs when: +𝛽√𝜎𝑛 +2 + 3(𝜏𝑛 +2 + 𝜏𝑡 +2) ≥ 𝜎𝑓 +where +𝜎𝑛 = normal stress +𝜏𝑛 = shear stress in direction of weld (local y) +𝜏𝑡 = shear stress normal to weld (local z) +𝜎𝑓 = failure stress +𝛽 = failure parameter +The component σn is nonzero for tensile values only. When the failure time, tf , is +reached the nodal rigid body becomes inactive and the constrained nodes may move +freely. The nodes in the butt weld may coincide. +Example: +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *CONSTRAINED_GENERALIZED_WELD_BUTT +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Weld two plates that butt up against each other at three nodal pair +$ locations. The nodal pairs are 32-33, 34-35 and 36-37. +$ +$ This requires 3 separate *CONSTRAINED_GENERALIZED_WELD_BUTT definitions, +$ one for each nodal pair. Each weld is to have a length (L) = 10, +$ thickness (D) = 2, and a transverse length (Lt) = 1. +$ +$ Failure is defined two ways: +$ Ductile failure if effective plastic strain exceeds 0.3 +$ Brittle failure if the stress failure criteria exceeds 0.25 +$ - scale the brittle failure criteria by beta = 0.9. +$ Note: beta > 1 weakens weld beta < 1 strengthens weld +$ +*CONSTRAINED_GENERALIZED_WELD_BUTT +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ nsid cid + 21 +$ tfail epsf sigy beta L D Lt + 0.3 0.250 0.9 10.0 2.0 1.0 +$ +$ +*CONSTRAINED_GENERALIZED_WELD_BUTT +$ nsid cid + 23 +$ tfail epsf sigy beta L D Lt + 0.3 0.250 0.9 10.0 2.0 1.0 +$ +$ +*CONSTRAINED_GENERALIZED_WELD_BUTT +$ nsid cid + 25 +$ tfail epsf sigy beta L D Lt + 0.3 0.250 0.9 10.0 2.0 1.0 +$ +$ +*SET_NODE_LIST +$ sid + 21 +$ nid1 nid2 + 32 33 +*SET_NODE_LIST + 23 + 34 35 +*SET_NODE_LIST + 25 + 36 37 +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +Cross Fillet Weld Card. Additional Card for the CROSS_FILLET keyword option. + Card 2 +1 +2 +3 +4 +Variable +TFAIL +EPSF +SIGY +BETA +Type +F +F +F +F +5 +L +F +6 +W +F +7 +A +F +8 +ALPHA +F +Nodal Pair Cards. Read NPR additional cards for the CROSS_FILLET keyword +option. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NODEA +NODEB +NCID +Type +I +I +I + VARIABLE +DESCRIPTION +TFAIL +Failure time for constraint set, tf . (default = 1.E+20) +EPSF +SIGY +Effective plastic strain at failure, 𝜖fail +𝑝 defines ductile failure. +𝜎𝑓 , stress at failure for brittle failure. +BETA +𝛽, failure parameter for brittle failure. +L +W +A +L, length of fillet weld . +w, separation of parallel fillet welds . +a, throat dimension of fillet weld . +ALPHA +𝛼, weld angle in degrees. +y2 +(a) +z1 +y1 +x1 +z2 +x2 +(c) +(b) +y3 +x3 +z3 +(d) +Figure 10-8. A simple cross fillet weld illustrates the required input. Here +NPR = 3 with nodal pairs (A = 2, B = 1), (A = 3, B = 1), and (A = 3, B = 2). The +local coordinate axes are shown. These axes are fixed in the rigid body and are +referenced to the local rigid body coordinate system which tracks the rigid +body rotation. + VARIABLE +NODEA +DESCRIPTION +Node ID, A, in weld pair (CROSS or COMBINED option only). +See Figure 10-8. +VARIABLE +DESCRIPTION +NODEB +Node ID, B, in weld pair (CROSS or COMBINED option only). +NCID +Local coordinate system ID (CROSS or COMBINED option only). +Combined Weld Cards: +Additional cards for the COMBINED keyword option. Read in NPR pairs of Cards 2 +and 3 for a total of 2 × NPR cards. + Card 2 +1 +2 +3 +4 +Variable +TFAIL +EPSF +SIGY +BETA +Type +F + Card 3 +1 +F +2 +F +3 +F +4 +Variable +NODEA +NODEB +NCID +WTYP +Type +I +I +I +I +5 +L +F +5 +6 +W +F +6 +7 +A +F +7 +8 +ALPHA +F +8 + VARIABLE +DESCRIPTION +TFAIL +Failure time for constraint set, tf . (default = 1.E+20) +EPSF +SIGY +Effective plastic strain at failure, 𝜖fail +𝑝 defines ductile failure. +𝜎𝑓 , stress at failure for brittle failure. +BETA +𝛽, failure parameter for brittle failure. +L +W +A +L, length of fillet/butt weld . +w, width of flange . +a, width of fillet weld . +ALPHA +𝛼, weld angle in degrees. +3 node +Fillet +Butt Weld +Figure 10-9. A combined weld is a mixture of fillet and butt welds. + VARIABLE +DESCRIPTION +NODEA +Node ID, A, in weld pair (CROSS or COMBINED option only). +NODEB +Node ID, B, in weld pair (CROSS or COMBINED option only). +NCID +Local coordinate system ID (CROSS or COMBINED option only). +WTYPE +Weld pair type (GENERAL option only). See Figure 10-9. +EQ.0: fillet weld +EQ.1: butt weld +*CONSTRAINED_GLOBAL +7 +8 +Purpose: Define a global boundary constraint plane. + Card 1 +Variable +Type +Default +1 +TC +I +0 +2 +RC +I +0 +3 +DIR +I +0 +4 +X +F +0 +5 +Y +F +0 +6 +Z +F +0 + VARIABLE +DESCRIPTION +TC +Translational Constraint: +EQ.1: constrained x translation, +EQ.2: constrained y translation, +EQ.3: constrained z translation, +EQ.4: constrained x and y translations, +EQ.5: constrained y and z translations, +EQ.6: constrained x and z translations, +EQ.7: constrained x, y, and z translations, +RC +Rotational Constraint: +EQ.1: constrained x-rotation, +EQ.2: constrained y-rotation, +EQ.3: constrained z-rotation, +EQ.4: constrained x and y rotations, +EQ.5: constrained y and z rotations, +EQ.6: constrained z and x rotations, +EQ.7: constrained x, y, and z rotations. +VARIABLE +DESCRIPTION +DIR +Direction of normal for constraint plane. +EQ.1: global x, +EQ.2: global y, +EQ.3: global z. +X +Y +Z +Global x-coordinate of a point on the constraint plane. +Global y-coordinate of a point on the constraint plane. +Global z-coordinate of a point on the constraint plane. +Remarks: +Nodes within a mesh-size-dependent tolerance are constrained on a global plane. This +option is recommended for use with r-method adaptive remeshing where nodal +constraints are lost during the remeshing phase. See *CONSTRAINED_LOCAL for +specifying constraints to nodes lying on a local plane. +*CONSTRAINED_INTERPOLATION_{OPTION} +Available options include: + +LOCAL +Purpose: Define an interpolation constraint. With this constraint type, the motion of a +single dependent node is interpolated from the motion of a set of independent nodes. +This option is useful for the redistribution of a load applied to the dependent node by +the surrounding independent nodes. This load may be a translational force or a +rotational moment. This keyword is typically used to model shell-brick and beam-brick +interfaces. +The mass and rotary inertia of the dependent nodal point is also redistributed. This +constraint is applied in the global coordinate system unless the option LOCAL is active. +One *CONSTRAINED_INTERPOLATION card is required for each constraint definition. +The input list of independent nodes is terminated when the next "*" card is found. In +explicit calculations the independent nodes cannot be dependent nodes in other +constraints such as nodal rigid bodies; however, implicit calculations are not bound by +this limitation. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ICID +DNID +DDOF +CIDD +ITYP +Type +Default +I +0 +I +I +I +0 +123456 optional +I +Independent Node Card Sets: +If LOCAL option is not set, for each independent node include the following card; if the +LOCAL keyword option is set, include only the following pair of cards. This input is +terminated at the next keyword (“*”) card. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +INID +IDOF +TWGHTX TWGHTY TWGHTZ RWGHTX RWGHTY RWGHTZ +Type +I +I +F +F +F +F +F +F +Default +0 +123456 +1.0 +TWGHTX TWGHTX TWGHTX TWGHTX TWGHTX +Local Coordinate Card. Additional card for the LOCAL keyword option to be paired +with card 2. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CIDI +Type +Default +I +0 + VARIABLE +DESCRIPTION +ICID +DNID +DDOF +Interpolation constraint ID. +Dependent node ID. This node should not be a member of a rigid +body, or elsewhere constrained in the input. +Dependent degrees-of-freedom. The list of dependent degrees-of- +freedom consists of a number with up to six digits, with each +digit representing a degree of freedom. For example, the value +1356 indicates that degrees of freedom 1, 3, 5, and 6 are controlled +by the constraint. The default is 123456. Digit: degree of freedom +ID's: +EQ.1: x +EQ.2: y +VARIABLE +DESCRIPTION +EQ.3: z +EQ.4: rotation about x axis +EQ.5: rotation about y axis +EQ.6: rotation about z axis +CIDD +Local coordinate system ID if LOCAL option is active. If blank +the global coordinate system is assumed. +ITYP +Specifies the meaning of INID. +EQ.0: INID is a node ID +EQ.1: INID is a node set ID +Independent node ID or node set ID. +Independent degrees-of-freedom using the same form as for the +dependent degrees-of-freedom, DDOF, above. +Weighting factor for node INID with active degrees-of-freedom +IDOF. This weight scales the x-translational component. It is +normally sufficient to define only TWGHTX even if its degree-of- +freedom is inactive since the other factors are set equal to this +input value as the default. There is no requirement on the values +that are chosen as the weighting factors, i.e., that they sum to +unity. The default value for the weighting factor is unity. +Weighting factor for node INID with active degrees-of-freedom +IDOF. This weight scales the y-translational component. +Weighting factor for node INID with active degrees-of-freedom +IDOF. This weight scales the z-translational component. +Weighting factor for node INID with active degrees-of-freedom +IDOF. This weight scales the x-rotational component. +Weighting factor for node INID with active degrees-of-freedom +IDOF. This weight scales the y-rotational component. +Weighting factor for node INID with active degrees-of-freedom +IDOF. This weight scales the z-rotational component. +INID +IDOF +TWGHTX +TWGHTY +TWGHTZ +RWGHTX +RWGHTY +RWGHTZ +CIDI +Local coordinate system ID if LOCAL option is active. If blank +the global coordinate system is assumed. +21 +22 +11 +45 +44 +33 +43 +Figure 10-10. Illustration of Example 1. +Example 1: +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *CONSTRAINED_INTERPOLATION (Beam to solid coupling) +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Tie a beam element to a solid element. +$ +$ The node of the beam to be tied does not share a common node with the solids. +$ If the beam node is shared, for example, then set ddof=456. +$ +*CONSTRAINED_INTERPOLATION +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ icid dnid ddof + 1 45 123456 +$ inid idof twghtx twghty twghtz rwghtx rwghty rwghtz + 22 123 + 44 123 + 43 123 +$ +*......... +$ +180 +179 +178 +177 +100 +99 +98 +97 +96 +Figure 10-11. Illustration of Example 2. +Example 2: +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *CONSTRAINED_INTERPOLATION (Load redistribution) +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Moment about normal axis of node 100 is converted to an equivalent load by +$ applying x-force resultants to the nodes lying along the right boundary +$ +*DEFINE_CURVE +1,0,0.,0.,0.,0.,0 +0.,0. +.1,10000. +*LOAD_NODE_POINT +100,6,1,1.0 +$ +*CONSTRAINED_INTERPOLATION +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ icid dnid ddof + 1 100 5 +$ inid idof twghtx twghty twghtz rwghtx rwghty rwghtz + 96 1 + 97 1 + 98 1 + 99 1 + 177 1 + 178 1 + 179 1 + 180 1 +$ +*......... +$ +*CONSTRAINED_INTERPOLATION_SPOTWELD +(prior notation *CONSTRAINED_SPR3 still works) +Purpose: Define a spotweld with failure. This model includes a plasticity-damage +model that reduces the force and moment resultants to zero as the spotweld fails. The +location of the spotweld is defined by a single node at the center of two connected +sheets. The domain of influence is specified by a radius, which should be approximate- +ly equal to the spotweld’s radius. The algorithm does a normal projection from the two +sheets to the spotweld node and locates all nodes within the user-defined diameter of +influence. The numerical implementation of this model is similar to the SPR2 model +(*CONSTRAINED_SPR2). + Card 1 +1 +2 +3 +4 +Variable +PID1 +PID2 +NSID +THICK +Type +I +I +I +F +5 +R +F +6 +7 +8 +STIFF +ALPHA1 MODEL +F +F +F +Default +none +none +none +none +none +none +none +1.0 + Card 2 +Variable +1 +RN +Type +F +2 +RS +F +3 +4 +5 +6 +7 +8 +BETA +LCF +LCUPF +LCUPR +DENS +INTP +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +Additional Card for MODEL = 2, 12, or 22. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +UPFN +UPFS +ALPHA2 +BETA2 +UPRN +UPRS +ALPHA3 +BETA3 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none +Additional Card for MODEL = 2, 12, or 22. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MRN +MRS +Type +F +F +Default +none +none + VARIABLE +DESCRIPTION +PID1 +PID2 +NSID +Part ID of first sheet. +Part ID of second sheet. +Node set ID of spotweld location nodes. +THICK +Total thickness of both sheets. +R +Spotweld radius. +STIFF +Elastic stiffness. Function ID if MODEL > 10. +ALPHA1 +Scaling factor 𝛼1. Function ID if MODEL > 10. +MODEL +Material behavior and damage model, see remarks. +EQ. 1: SPR3 (default), +EQ. 2: SPR4, +EQ.11: same as 1 with selected material parameters as +functions, +EQ.12: same as 2 with selected material parameters as +functions, +EQ.21: same as 11 with slight modification, see remarks, +EQ.22: same as 12 with slight modification, see remarks. +RN +RS +Tensile strength factor. Function ID if MODEL > 10. +Shear strength factor. Function ID if MODEL > 10. +BETA +Exponent for plastic potential 𝛽1. Function ID if MODEL > 10. +VARIABLE +DESCRIPTION +LCF +LCUPF +LCUPR +DENS +INTP +UPFN +UPFS +Load curve ID describing force versus plastic displacement: +𝐹0(𝑢̅𝑝𝑙). +Load curve ID describing plastic initiation displacement versus +𝑝𝑙(𝜅). Only for MODEL = 1, 11, or 21. +mode mixity: 𝑢̅0 +Load curve ID describing plastic rupture displacement versus +𝑝𝑙(𝜅). Only for MODEL = 1, 11, or 21. +mode mixity: 𝑢̅𝑓 +Spotweld density (necessary for time step calculation). +Flag for interpolation. +EQ.0: linear (default), +EQ.1: uniform, +EQ.2: inverse distance weighting. +𝑝𝑙,𝑛 . +Plastic initiation displacement in normal direction 𝑢̅0,ref +𝑝𝑙,𝑠 . +Plastic initiation displacement in shear direction 𝑢̅0,ref +ALPHA2 +Plastic initiation displacement scaling factor 𝛼2 . +BETA2 +UPRN +UPRS +Exponent for plastic initiation displacement 𝛽2. +𝑝𝑙,𝑛 . +Plastic rupture displacement in normal direction 𝑢̅𝑓 ,ref +𝑝𝑙,𝑠 . +Plastic rupture displacement in shear direction 𝑢̅𝑓 ,ref +ALPHA3 +Plastic rupture displacement scaling factor 𝛼3 . +BETA3 +Exponent for plastic rupture displacement 𝛽3. +Proportionality factor for dependency RN. +Proportionality factor for dependency RS. +MRN +MRS +Remarks: +When this feature is used, it is recommended to use the drilling rotation constraint +method for the connected components in explicit analysis, i.e. parameter DRCPSID of +*CONTROL_SHELL should refer to all shell parts +TION_SPOTWELD connections. +involved +in INTERPOLA- +MODEL = 1, 11, or 21 (“SPR3”) +This numerical model is similar to the self-piercing rivet model SPR2 but with some differences to make it more suitable for spotwelds. +The first difference is symmetric behavior of the spotweld connection, i.e. there is no +distinction between a master sheet and a slave sheet. This is done by averaging the +normals of both parts and by always distributing the balance moments equally to both +sides. +The second difference is that there are not only two but three quantities to describe the +kinematics, namely the normal relative displacement 𝛿𝑛, the tangential relative +displacement 𝛿𝑡, and the relative rotation 𝜔𝑏 - all with respect to the plane-of-maximum +opening. I.e. a relative displacement vector is defined as +𝐮 = (𝛿𝑛, 𝛿𝑡, 𝜔𝑏) +The third difference is the underlying material model. With the described kinematic +quantities, an elastic effective force vector is computed first: +𝐟 ̃ = (𝑓𝑛, 𝑓𝑡, 𝑚𝑏) = STIFF × 𝐮 = STIFF × (𝜹𝒏, 𝜹𝒕, 𝝎𝒃) +From that, two resultant forces for normal direction and tangential direction (shear) are +computed via +Then, a yield function is defined for plastic behavior +𝐹𝑛 = ⟨𝑓𝑛⟩ + 𝛼1𝑚𝑏, +𝐹𝑠 = 𝑓𝑡 +𝜙(𝐟 ̃, 𝒖̅pl) = 𝑃(𝐟 ̃) − 𝐹0(𝒖̅pl) ≤ 0 +with relative plastic displacement 𝑢̅𝑝𝑙, potential P +𝑃(𝐟 ̃) = [( +𝐹𝑛 +𝑅𝑛 +) ++ ( +𝐹𝑠 +𝑅𝑠 +𝟏/𝜷 +] +) +(cid:448)(cid:1377) +(cid:448)(cid:1377)(cid:9)(cid:487)(cid:1135)(cid:981)(cid:10) +(cid:487)(cid:1135)(cid:981) +(cid:1377) +(cid:1377) (cid:12) (cid:487)(cid:1135)(cid:981) +(cid:487)(cid:1135)(cid:981) +(cid:1401) +(cid:487)(cid:1135)(cid:981) +Figure 10-12. Force-displacement curve: plasticity and linear damage +and isotropic hardening described by load curve LCF : +𝐹0 = 𝐹0(𝒖̅pl) +In addition, a linear softening evolution is incorporated, where damage is defined as: +pl(𝜅) +𝑑 = +𝑢̅pl − 𝑢̅0 +pl(𝜅) +𝑢̅𝑓 +, +0 < 𝑑 < 1 +with mode mixity +𝜅 = +arctan ( +𝐹𝑛 +𝐹𝑠 +) , 0 < 𝜅 < 1 +Finally, the nominal force is computed as: +𝐟 = (1 − 𝑑)𝐟 ̃ +MODEL = 2, 12, or 22 (“SPR4”) +In this approach, the relative displacement vector is defined as in model 1 +The elastic effective force vector is computed using the elastic stiffness STIFF +𝐟 ̃ = (𝑓𝑛, 𝑓𝑡) = STIFF × 𝐮 = STIFF × (𝜹𝒏, 𝜹𝒕) +𝐮 = (𝛿𝑛, 𝛿𝑡) +A yield function is defined for plastic behavior +𝜙(𝐟 ̃, 𝒖̅𝒑𝒍) = 𝑃(𝐟 ̃) − 𝐹0(𝒖̅𝒑𝒍) ≤ 0 +with relative plastic displacement 𝑢̅𝑝𝑙, potential P +𝑃(𝐟 ̃) = [( +𝑓𝑛 +𝑅̃ 𝑛 +𝜷𝟏 +) ++ ( +𝑓𝑡 +𝑅̃ 𝑠 +𝟏/𝜷𝟏 +) +] +wherein 𝑅̃ 𝑛 and 𝑅̃ 𝑠 represents the load capacity in normal and tangential direction +respectively. They are calculated by the values of RN and RS and the influence of +relative rotation angle 𝜔𝑏scaled by ALPHA1 +𝑅̃ 𝑠 = 𝑅𝑠 +𝑅̃ 𝑛 = 𝑅𝑛(1 − 𝛼1 𝜔𝑏) +In addition, a linear softening evolution is incorporated, where damage is defined as: +𝑑 = +𝑝𝑙 +𝑢̅𝑝𝑙 − 𝑢̅0 +𝑝𝑙 +𝑢̅𝑓 +, +0 < 𝑑 < 1 +The calculation of 𝑢̅0 +𝑝𝑙 and 𝑢̅𝑓 +𝑝𝑙 is done by solving the following equations +𝛽2 +𝑝𝑙,𝑛 +𝑢̅0 +⎤ +⎡ +⎥ +⎢ +𝑝𝑙,𝑛 (1 − 𝛼2𝜔𝑏)⎦ +𝑢̅0,ref +⎣ +⎧ +{ +⎨ +{ +⎩ ++ +𝑝𝑙,𝑠 +⎜⎜⎜⎛ 𝑢̅0 +𝑝𝑙,𝑠 +𝑢̅0,𝑟𝑒𝑓 +⎝ +⎟⎟⎟⎞ +⎠ +𝛽2 +𝛽2 +⎫ +} +⎬ +} +⎭ +− 1 = 0 +𝑝𝑙 +𝑝𝑙,𝑛 = sin(𝜑) 𝑢̅0 +𝑢̅0 +𝑝𝑙 +𝑝𝑙,𝑠 = c𝑜𝑠(𝜑)𝑢̅0 +𝑢̅0 +𝛽3 +𝑝𝑙,𝑛 +𝑢̅𝑓 +⎤ +⎡ +⎥ +⎢ +𝑝𝑙,𝑛 (1 − 𝛼3𝜔𝑏)⎦ +𝑢̅𝑓 ,𝑟𝑒𝑓 +⎣ +⎧ +{{ +⎨ +{{ +⎩ ++ +𝑝𝑙,𝑠 +⎜⎜⎜⎛ 𝑢̅𝑓 +𝑝𝑙,𝑠 +𝑢̅𝑓 ,𝑟𝑒𝑓 +⎝ +𝛽3 +⎟⎟⎟⎞ +⎠ +𝛽3 +⎫ +}} +⎬ +}} +⎭ +− 1 = 0 +considering the load angle 𝜑 +𝑝𝑙 +𝑝𝑙,𝑛 = sin(𝜑) 𝑢̅𝑓 +𝑢̅𝑓 +𝑝𝑙 +𝑝𝑙,𝑠 = c𝑜𝑠(𝜑)𝑢̅𝑓 +𝑢̅𝑓 +𝜑 = arctan ( +𝑓𝑛 +𝑓𝑠 +) +To describe a rate dependent behavior a plastic deformation rate 𝑢̅ +̇𝑝𝑙 is defined by +̇𝑝𝑙 = +𝑢̅ +Δ𝑢̅𝑝𝑙 +Δ𝑡 +wherein Δ𝑢̅𝑝𝑙 is the plastic increment in the current time step and Δ𝑡 is the time step +size. If MRN and MRS are defined, the calculation of 𝑅̃ 𝑛 and 𝑅̃ 𝑠 is changed to +𝑅̃ 𝑛(𝑢̅ +̇𝑝𝑙) = (𝑅𝑛 + 𝑚𝑅𝑛𝑢̅ +̇𝑝𝑙)(1 − 𝛼1 𝜔𝑏) +̇𝑝𝑙) = 𝑅𝑠 + 𝑚𝑅𝑠𝑢̅ +A detailed description of the SPR4 approach (MODEL = 2) is given in Bier and Sommer +[2013], where this model is called “SPR3_IWM”. +𝑅̃ 𝑠(𝑢̅ +̇𝑝𝑙 +MODEL > 10 +If MODEL is chosen to be greater than 10, then 5 variables have to be defined as +function IDs: STIFF, ALPHA1, RN, RS, and BETA. These functions incorporate the +following input values: thicknesses of both weld partners (t1, t2) and maximum +engineering yield stresses, also called necking points (sm1, sm2). For ALPHA1 = 100 +such a function could look like, +*DEFINE_FUNCTION + 100 + func(t1,t2,sm1,sm2)=sm1/sm2 +(This function is only a demonstration, it does not make any physical sense). For +MODEL = 11 or 12, the master part is the first weld partner represented by t1 and sm1. +For MODEL = 21 or 22, the thinner part is the first weld partner. Since material +parameters have to be identified from both weld partners during initialization, this +feature is only available for a subset of material models at the moment, namely no. 24, +120, 123, and 124. +*CONSTRAINED_JOINT_OPTION_{OPTION}_{OPTION}_{OPTION} +Available forms include (one is mandatory): +*CONSTRAINED_JOINT_SPHERICAL +*CONSTRAINED_JOINT_REVOLUTE +*CONSTRAINED_JOINT_CYLINDRICAL +*CONSTRAINED_JOINT_PLANAR +*CONSTRAINED_JOINT_UNIVERSAL +*CONSTRAINED_JOINT_TRANSLATIONAL +*CONSTRAINED_JOINT_LOCKING +*CONSTRAINED_JOINT_TRANSLATIONAL_MOTOR +*CONSTRAINED_JOINT_ROTATIONAL_MOTOR +*CONSTRAINED_JOINT_GEARS +*CONSTRAINED_JOINT_RACK_AND_PINION +*CONSTRAINED_JOINT_CONSTANT_VELOCITY +*CONSTRAINED_JOINT_PULLEY +*CONSTRAINED_JOINT_SCREW +If the force output data is to be transformed into a local coordinate use the option: +LOCAL +to define a joint ID and heading the following option is available: +ID +and to define failure for penalty-based joints (LMF = 0 in *CONTROL_RIGID) use: +FAILURE +The ordering of the bracketed options is arbitrary. +Purpose: Define a joint between two rigid bodies. +*CONSTRAINED +Card 1: +required for all joint types +Card 2: +required for joint types: MOTOR, GEARS, RACK_AND_PINION, +PULLEY, and SCREW + Optional Card: +required only if LOCAL is specified in the keyword +In the first seven joint types above excepting the Universal joint, the nodal points within +the nodal pairs (1, 2), (3, 4), and (5, 6) should coincide +in the initial configuration, and the nodal pairs should be as far apart as possible to +obtain the best behavior. For the Universal Joint the nodes within the nodal pair (3, 4) +do not coincide, but the lines drawn between nodes (1, 3) and (2, 4) must be +perpendicular. +For the Gear joint the nodes within the nodal pair (1, 2) must not coincide. +When the penalty method is used , at each time step, the +relative penalty stiffness is multiplied by a function dependent on the step size to give +the maximum stiffness that will not destroy the stability of the solution. Instabilities +can result in the explicit time integration scheme if the penalty stiffness is too large. If +instabilities occur, the recommended way to eliminate these problems is to decrease the +time step or reduce the scale factor on the penalties. +For cylindrical joints, by setting node 3 to zero, it is possible to use a cylindrical joint to +join a node that is not on a rigid body (node 1) to a rigid body (nodes 2 and 4). +ID Card. Additional card for ID keyword option. + Optional +1 +2 +3 +4 +5 +6 +7 +8 +Variable +JID +Type +I +HEADING +A70 +The heading is picked up by some of the peripheral LS-DYNA codes to aid in post- +processing. + VARIABLE +DESCRIPTION +JID +Joint ID. This must be a unique number. +HEADING +Joint descriptor. It is suggested that unique descriptions be used. +Card 1 +Variable +Type +Default +1 +N1 +I +0 +2 +N2 +I +0 +3 +N3 +I +0 +4 +N4 +I +0 +5 +N5 +I +0 +6 +N6 +I +0 +7 +8 +RPS +DAMP +F +F +1.0 +1.0 + VARIABLE +DESCRIPTION +N1 +N2 +N3 +N4 +N5 +N6 +Node 1, in rigid body A. Define for all joint types. +Node 2, in rigid body B. Define for all joint types. +Node 3, in rigid body A. Define for all joint types except +SPHERICAL. +Node 4, in rigid body B. Define for all joint types except +SPHERICAL. +Node 5, in rigid body A. Define for joint types TRANSLATION- +AL, LOCKING, ROTATIONAL_MOTOR, CONSTANT_VELOCI- +TY, GEARS, RACK_AND_PINION, PULLEY, and SCREW +Node 6, in rigid body B. Define for joint types TRANSLATION- +AL, LOCKING, ROTATIONAL_MOTOR, CONSTANT_VELOCI- +TY, GEARS, RACK_AND_PINION, PULLEY, and SCREW +RPS +Relative penalty stiffness (default = 1.0): +GT.0.0: constant value, +LT.0.0: time dependent value given by load curve ID = -RPS +(only for SPHERICAL, REVOLUTE, and CYLINDRI- +CAL). +DAMP +Damping scale factor on default damping value. (Revolute and +Spherical Joints): +EQ.0.0: +default is set to 1.0, +GT.0.0.AND.LE.0.01: no damping is used. +Rotational Properties Card. Additional card for joint types MOTOR, GEARS, +RACK_AND_PINION, PULLEY, and SCREW. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PARM +LCID +TYPE +R1 +H_ANGLE +Type +F +I +I +F +F +Default +none +0.0 + VARIABLE +DESCRIPTION +PARM +Parameter, which a function of joint type: +Gears: define 𝑅2/𝑅1 + Rack and Pinion: define ℎ +Pulley: define 𝑅2/𝑅1 +Screw: define 𝑥̇/𝜔 +Motors: leave blank +Define load curve ID for MOTOR joints. +Define integer flag for MOTOR joints as follows: +EQ.0: translational/rotational velocity +EQ.1: translational/rotational acceleration +EQ.2: translational/rotational displacement +Radius, 𝑅1, for the gear and pulley joint type. If left undefined, +nodal points 5 and 6 are assumed to be on the outer radius. The +value of R1 and R2 affect the reaction forces written to output. +The forces are calculated from the moments by dividing them by +the radii. +LCID +TYPE +R1 +H_ANGLE +Helix angle in degrees. This is only necessary for the gear joint if +the gears do not mesh tangentially, e.g., worm gears, see remarks +below for a definition. +Local Card. Additional card required for LOCAL keyword option. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RAID +LST +Type +Default +I +0 +I +0 + VARIABLE +RAID +DESCRIPTION +Rigid body or accelerometer ID. The force resultants are output +in the local system of the rigid body or accelerometer. +LST +Flag for local system type: +EQ.0: rigid body +EQ.1: accelerometer +Failure Card 1. Additional card for FAILURE keyword option. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CID +TFAIL +COUPL +Type +Default +I +0 +F +0 +F +0. +Failure Card 2. Additional card for FAILURE keyword option. + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NXX +NYY +NZZ +MXX +MYY +MZZ +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +VARIABLE +CID +DESCRIPTION +Coordinate ID for resultants in the failure criteria. If zero, the +global coordinate system is used. +TFAIL +Time for joint failure. If zero, joint never fails. +COUPL +NXX +NYY +NZZ +MXX +MYY +MZZ +Coupling between the force and moment failure criteria. If +COUPL is less than or equal to zero, the failure criteria is identical +to the spotwelds. When COUPL is greater than zero, the force +and moment results are considered independently. See the +remark below. +Axial force resultant 𝑁𝑥𝑥𝐹at failure. If zero, failure due to this +component is not considered. +Force resultant 𝑁𝑦𝑦𝐹 at failure. If zero, failure due to this +component is not considered. +Force resultant 𝑁𝑧𝑧𝐹 at failure. If zero, failure due to this +component is not considered. +Torsional moment resultant 𝑀𝑧𝑧𝐹 at failure. If zero, failure due to +this component is not considered. +Moment resultant 𝑀𝑦𝑦𝐹 at failure. If zero, failure due to this +component is not considered. +Moment resultant 𝑀𝑧𝑧𝐹 at failure. If zero, failure due to this +component is not considered. +Node 2 at +center +The axial +direction, e1 +The tangential +direction, e2 +Tangent vector +to the teeth e3 +Figure 10-13. Helix angle 𝛼 definition, gear #2 viewed from the extension of +node 𝑛2 to node 𝑛6. +Remarks: +The moments for the revolute, cylindrical, planar, translational, and locking joints are +calculated at the midpoint of nodes N1 and N3. The moments for the spherical, +universal, constant velocity, gear, pulley, and rack and pinion joints are calculated at +node N1. When COUPL is less than or equal to zero, the failure criteria is +( +𝑁𝑥𝑥 +𝑁𝑥𝑥𝐹 +) ++ ( +𝑁𝑦𝑦 +𝑁𝑦𝑦𝐹 +) ++ ( +𝑁𝑧𝑧 +𝑁𝑧𝑧𝐹 +) ++ ( +𝑀𝑥𝑥 +𝑀𝑥𝑥𝐹 +) ++ ( +𝑀𝑦𝑦 +𝑀𝑦𝑦𝐹 +) ++ ( +𝑀𝑧𝑧 +𝑀𝑧𝑧𝐹 +) +− 1 = 0. +Otherwise, it consists of both +and +( +𝑁𝑥𝑥 +𝑁𝑥𝑥𝐹 +) ++ ( +𝑁𝑦𝑦 +𝑁𝑦𝑦𝐹 +) ++ ( +𝑁𝑧𝑧 +𝑁𝑧𝑧𝐹 +) +− 1 = 0, +( +𝑀𝑥𝑥 +𝑀𝑥𝑥𝐹 +) ++ ( +𝑀𝑦𝑦 +𝑀𝑦𝑦𝐹 +) ++ ( +𝑀𝑧𝑧 +𝑀𝑧𝑧𝐹 +) +− 1 = 0. +For a gear joint, the relative direction and magnitude of rotation between the two gears +is determined by the helix angle. Let 𝐞1 be the unit normal directed from node 2 to 4, +which corresponds to the second gear’s rotation axis. See Figure 10-23. Let 𝐞2 be +defined as the positively oriented tangent vector to motion of the teeth when spun +about the 𝐞1 axis (the gear’s axis). See Figure 10-13. The helix angle 𝛼 characterizes the +deviation of the teeth axis from the gear axis. In particular, 𝛼 is defined as the angle +between the direction of teeth, called 𝐞3, and the axis of the gear 𝐞1, +𝐞3 = cos𝛼𝐞1 + sin𝛼𝐞2. +The gears are assumed to be setup so that the teeth initially fit having matching 𝐞3 +directions. A nonzero helix angle is typically used to model worm gears. +1,2 +Radial cross section +Figure 10-14. Spherical joint. The relative motion of the rigid bodies is +constrained so that nodes which are initially coincident remain coincident. In +the above figure the socket’s node is not interior to the socket—LS-DYNA does +not require that a rigid body’s nodes be interior to the body. +Centerline +Centerline +3,4 +1,2 +Figure 10-15. Revolute Joint. Nodes 1 and 2 are coincident; nodes 3 and 4 are +coincident. Nodes 1 and 3 belong to rigid body A; nodes 2 and 4 belong to rigid +body B. The relative motion of the two rigid bodies is restricted to rotations +about the axis formed by the two pairs of coincident nodes. This axis is labeled +the “centerline”. +Initial +Current +Centerline +1,2 +3,4 +Figure 10-16. Cylindrical Joint. This joint is derived from the rotational joint by +relaxing the constraints along the centerline. This joint admits relative rotation +and translation along the centerline. +Initial +Current +Centerline +1,2 +3,4 +5,6 +Figure 10-17. Translational joint. This is a cylindrical joint with a third pair of +off-centerline nodes which restrict rotation. Aside from translation along the +centerline, the two rigid bodies are stuck together. +Figure 10-18. Planar joint. This joint is derived from the rotational joint by +relaxing the constraints normal to the centerline. Relative displacements along +the direction of the centerline are excluded. +1,2 +Figure 10-19. Universal Joint. Nodes 1 and 2 are initially coincident. The +segments formed by nodal pairs (1, 3) and (2, 4) must be orthogonal; they serve +as axes about which the two bodies may undergo relative rotation. The +universal joint excludes all other relative motion and the axes remain +orthogonal at all time. +Initial, Final +1,2 +5,6 +3,43,4 +Figure 10-20. Locking Joint. A locking joint couples two rigid bodies in all six +degrees-of-freedom. The forces and moments required to form this coupling +are written to the jntforc file (*DATABASE_JNTFORC). As stated in the +Remarks, forces and moments in jntforc are calculated halfway between N1 +and N3. Nodal pairs (1, 2), (3, 4) and (5, 6) must be coincident. The three +spatial points corresponding to three nodal pairs must be neither collocated +nor collinear. +Centerline +† +Load Curve +Time +Figure 10-21. Translational motor joint. This joint is usually used in +combination with a translational or a cylindrical joint. Node 1 and node 2 +belong to the first rigid body and the second rigid body, resp. Furthermore, +nodes 1 and 2 must be coincident. Node 3 may belong to either rigid body. +The vector from node 2 to node 3 is the direction of relative motion. Node 4 is +not used and can be left blank. The value of the load curve may specify any of +several kinematic measures; see TYPE. +Load curve defines relative +rotational motion in radians +per unit time. +Figure 10-22. Rotational motor joint. This joint can be used in combination +with other joints such as the revolute or cylindrical joints. +Node 1 at +center +R1 +R2 +Node 1 at +center +Node 2 at +center +R2 +Node 2 at +center +R1 +Figure 10-23. Gear joints. Nodal pairs (1, 3) and (2, 4) define axes that are +orthogonal to the gears. Nodal pairs (1, 5) and (2, 6) define vectors in the plane +of the gears. The ratio 𝑅2 𝑅1⁄ + is specified but need not necessarily correspond +to the geometry, if for instance the gear consists of spiral grooves. Note that +the gear joint in itself does not maintain the contact point but this requires +additional treatment, such as accompanying it with other joints. +Node 1 at the +center of the pinion +Node 2 inside +the rack +Figure 10-24. Rack and pinion joint. Nodal pair (1, 3) defines the axis of +rotation of the first body (the pinion). Nodal pair (1, 5) is a vector in the +plane of the pinion and is orthogonal to nodal pair (1, 3). Nodal pair (2, 4) +defines the direction of travel for the second body (the rack). Nodal pair +(2, 6) is parallel to the axis of the pinion and is thus parallel to nodal pair +(1, 3). The value h is specified. The velocity of the rack is ℎ𝜔pinion. +1 2 +Figure 10-25. Constant velocity joint. Nodal pairs (1, 3) and (2, 4) define an +axes for the constant angular velocity, and nodal pairs (1, 5) are orthogonal +vectors. Here nodal points 1 and 2 must be coincident. +R2 +R1 +Node 1 +at Center +Node 2 at Center +Figure 10-26. Pulley joint. Nodal pairs (1, 3) and (2, 4) define axes that are +orthogonal to the pulleys. Nodal pairs (1, 5) and (2, 6) define vectors in the +plane of the pulleys. The ratio 𝑅2 𝑅1⁄ + is specified. +Screw Centerline +1,2 +5,6 +3,4 +Figure 10-27. Screw joint. The second body translates in response to the spin +of the first body. Nodal pairs (1, 3) and (2, 4) lie along the same axis and nodal +pairs (1, 5) and (2, 6) are orthogonal vectors. The helix ratio, 𝑥̇ +𝜔⁄ , is specified. +*CONSTRAINED_JOINT +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *CONSTRAINED_JOINT_PLANAR +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Define a planar joint between two rigid bodies. +$ - Nodes 91 and 94 are on rigid body 1. +$ - Nodes 21 and 150 are on rigid body 2. +$ - Nodes 91 and 21 must be coincident. +$ * These nodes define the origin of the joint plane. +$ - Nodes 94 and 150 must be coincident. +$ * To accomplish this, massless node 150 is artificially created at +$ the same coordinates as node 94 and then added to rigid body 2. +$ * These nodes define the normal of the joint plane (e.g., the +$ vector from node 91 to 94 defines the planes' normal). +$ +*CONSTRAINED_JOINT_PLANAR +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ n1 n2 n3 n4 n5 n6 rps + 91 21 94 150 0.000E+00 +$ +$ +*NODE +$ nid x y z tc rc + 150 0.00 3.00 0.00 0 0 +$ +*CONSTRAINED_EXTRA_NODES_SET +$ pid nsid + 2 6 +$*SET_NODE_LIST +$ sid + 6 +$ nid1 + 150 +$ +$$$ request output for joint force data +$ +*DATABASE_JNTFORC +$ dt/cycl lcdt + 0.0001 +$ +Example 2: +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *CONSTRAINED_JOINT_REVOLUTE +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Create a revolute joint between two rigid bodies. The rigid bodies must +$ share a common edge to define the joint along. This edge, however, must +$ not have the nodes merged together. Rigid bodies A and B will rotate +$ relative to each other along the axis defined by the common edge. +$ +$ Nodes 1 and 2 are on rigid body A and coincide with nodes 9 and 10 +$ on rigid body B, respectively. (This defines the axis of rotation.) +$ +$ The relative penalty stiffness on the revolute joint is to be 1.0, +$ +*CONSTRAINED_JOINT_REVOLUTE +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ n1 n2 n3 n4 n5 n6 rps damp + 1 9 2 10 1.0 +$ +$ Note: A joint stiffness is not mandatory for this joint to work. +$ However, to see how a joint stiffness can be defined for this +$ particular joint, see the corresponding example listed in: +$ *CONSTRAINED_JOINT_STIFFNESS_GENERALIZED +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +*CONSTRAINED_JOINT_COOR_OPTION_{OPTION}_{OPTION}_{OPTION} +Available forms include (one is mandatory): +*CONSTRAINED_JOINT_COOR_SPHERICAL +*CONSTRAINED_JOINT_COOR_REVOLUTE +*CONSTRAINED_JOINT_COOR_CYLINDRICAL +*CONSTRAINED_JOINT_COOR_PLANAR +*CONSTRAINED_JOINT_COOR_UNIVERSAL +*CONSTRAINED_JOINT_COOR_TRANSLATIONAL +*CONSTRAINED_JOINT_COOR_LOCKING +*CONSTRAINED_JOINT_COOR_TRANSLATIONAL_MOTOR +*CONSTRAINED_JOINT_COOR_ROTATIONAL_MOTOR +*CONSTRAINED_JOINT_COOR_GEARS +*CONSTRAINED_JOINT_COOR_RACK_AND_PINION +*CONSTRAINED_JOINT_COOR_CONSTANT_VELOCITY +*CONSTRAINED_JOINT_COOR_PULLEY +*CONSTRAINED_JOINT_COOR_SCREW +If the force output data is to be transformed into a local coordinate use the option: +LOCAL +to define a joint ID and heading the following option is available: +ID +and to define failure for penalty-based joints (LMF = 0 in *CONTROL_RIGID) use: +FAILURE +The ordering of the bracketed options is arbitrary. +Purpose: Define a joint between two rigid bodies, see Figure. The connection +coordinates are given instead of the nodal point IDs required in the previous section, +*CONSTRAINED_JOINT_{OPTION}. Nodes are automatically generated for each +coordinate and are constrained to the rigid body. Where coincident nodes are expected +in the initial configuration, only one connection coordinate is needed since the +connection coordinate for the second node, if given, is ignored. The created nodal ID’s +are chosen to exceed the maximum user ID. The coordinates of the joint nodes are +specified on Cards 2 - 7. The input which follows Card 7 is identical to that in the +previous section. +Card Format: +Cards 1 - 7: +required for all joint types +Card 8: +required for joint types: MOTOR, GEARS, RACK_AND_PINION, +PULLEY, and SCREW + Optional Card: +required when LOCAL is specified in the keyword +In the first seven joint types above excepting the Universal joint, the coordinate points +within the nodal pairs (1, 2), (3, 4), and (5, 6) should +coincide in the initial configuration, and the nodal pairs should be as far apart as +possible to obtain the best behavior. For the Universal Joint the nodes within the +coordinate pair (3, 4) do not coincide, but the lines drawn between nodes (1, 3) and (2, 4) +must be perpendicular. +For the Gear joint the nodes within the coordinate pair (1, 2) must not coincide. +When the penalty method is used , at each time step, the +relative penalty stiffness is multiplied by a function dependent on the step size to give +the maximum stiffness that will not destroy the stability of the solution. LS-DYNA’s +explicit time integrator can become unstable when the penalty stiffness is too large. If +instabilities occur, the recommended way to eliminate these problems is to decrease the +time step or reduce the scale factor on the penalties. +For cylindrical joints, by setting node 3 to zero, it is possible to use a cylindrical joint to +join a node that is not on a rigid body (node 1) to a rigid body (nodes 2 and 4). +ID Card. Additional card for the ID keyword option. + Optional +1 +2 +3 +4 +5 +6 +7 +8 +Variable +JID +Type +I +HEADING +A70 +The heading is picked up by some of the peripheral LS-DYNA codes to aid in post- +processing. +VARIABLE +DESCRIPTION +JID +Joint ID. This must be a unique number. +HEADING +Joint descriptor. It is suggested that unique descriptions be used. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RBID_A +RBID_B +RPS +DAMP +TMASS +RMASS +Type +I +I +F + Card 2 +Variable +1 +X1 +Type +F + Card 3 +Variable +1 +X2 +Type +F + Card 4 +Variable +1 +X3 +Type +F +2 +Y1 +F +2 +Y2 +F +2 +Y3 +F +3 +Z1 +F +3 +Z2 +F +3 +Z3 +F +F +4 +F +5 +F +6 +7 +8 +4 +5 +6 +7 +8 +4 +5 +6 +7 +Card 5 +Variable +1 +X4 +Type +F + Card 6 +Variable +1 +X5 +Type +F + Card 7 +Variable +1 +X6 +Type +F +2 +Y4 +F +2 +Y5 +F +2 +Y6 +F +3 +Z4 +F +3 +Z5 +F +3 +Z6 +F +4 +5 +6 +7 +8 +4 +5 +6 +7 +8 +4 +5 +6 +7 +8 + VARIABLE +DESCRIPTION +RBID_A +Part ID of rigid body A. +RBID_B +Part ID of rigid body B. +RPS +Relative penalty stiffness (default = 1.0). +DAMP +Damping scale factor on default damping value. (Revolute and +Spherical Joints): +EQ.0.0: +default is set to 1.0, +GT.0.0 and LE.0.01: no damping is used. +TMASS +RMASS +Lumped translational mass. The mass is equally split between +the first points defined for rigid bodies A and B. +Lumped rotational inertia. The inertia is equally split between +the first points defined for rigid bodies A and B. +X1, Y1, Z1 +Coordinate of point 1, in rigid body A. Define for all joint types. +VARIABLE +X2, Y2, Z2 +DESCRIPTION +Coordinate of point 2, in rigid body B. If points 1 and 2 are +coincident in the specified joint type, the coordinate for point 1 is +used. +X3, Y3, Z31 +Coordinate of point 3, in rigid body A. Define for all joint types. +X4, Y4, Z4 +Coordinate of point 4, in rigid body B. If points 3 and 4 are +coincident in the specified joint type, the coordinate for point 3 is +used. +X5, Y5, Z5 +Coordinate of point 5, in rigid body A. Define for all joint types. +X6, Y6, Z6 +Coordinate of point 6, in rigid body B. If points 5 and 6 are +coincident in the specified joint type, the coordinate for point 5 is +used. +Rotational Properties Card. Additional card for joint types MOTOR, GEARS, +RACK_AND_PINION, PULLEY, and SCREW. +5 +6 +7 +8 + Card 8 +1 +2 +3 +Variable +PARM +LCID +TYPE +Type +F +I +I +4 +R1 +F +Default +none + VARIABLE +DESCRIPTION +PARM +Parameter, which a function of joint type: +Gears: define 𝑅2/𝑅1 + Rack and Pinion: define ℎ +Pulley: define 𝑅2/𝑅1 +Screw: define 𝑥̇/𝜔 +Motors: leave blank +LCID +Define load curve ID for MOTOR joints. +VARIABLE +DESCRIPTION +TYPE +Define integer flag for MOTOR joints as follows: +EQ.0: translational/rotational velocity +EQ.1: translational/rotational acceleration +EQ.2: translational/rotational displacement +R1 +Radius, 𝑅1, for the gear and pulley joint type. If left undefined, +nodal points 5 and 6 are assumed to be on the outer radius. R1 is +the moment arm that goes into calculating the joint reaction +forces. The ratio R2/R1 gives the transmitted moments, but not +the forces. The force is moment divided by distance R1. +Local Card. Additional card for LOCAL keyword option. + Card 9 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RAID +LST +Type +Default +I +0 +I +0 + VARIABLE +RAID +DESCRIPTION +Rigid body or accelerometer ID. The force resultants are output +in the local system of the rigid body or accelerometer. +LST +Flag for local system type: +EQ.0: rigid body +EQ.1: accelerometer +Failure Card 1. Additional card for the FAILURE keyword option. + Card 10 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CID +TFAIL +COUPL +Type +Default +I +0 +F +0 +F +0. +Failure Card 2. Additional card for the FAILURE keyword option. + Card 11 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NXX +NYY +NZZ +MXX +MYY +MZZ +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 + VARIABLE +CID +DESCRIPTION +Coordinate ID for resultants in the failure criteria. If zero, the +global coordinate system is used. +TFAIL +Time for joint failure. If zero, joint never fails. +COUPL +NXX +NYY +NZZ +Coupling between the force and moment failure criteria. If COU- +PL is less than or equal to zero, the failure criteria is identical to +the spotwelds. When COUPL is greater than zero, the force and +moment results are considered independently. See the remarks in +*CONSTRAINED_JOINT_{OPTION}. +Axial force resultant 𝑁𝑥𝑥𝐹at failure. If zero, failure due to this +component is not considered. +Force resultant 𝑁𝑌𝑌𝐹 at failure. If zero, failure due to this +component is not considered. +Force resultant 𝑁𝑧𝑧𝐹 at failure. If zero, failure due to this +component is not considered. +VARIABLE +DESCRIPTION +MXX +MYY +MZZ +Torsional moment resultant 𝑀𝑋𝑋𝐹 at failure. If zero, failure due +to this component is not considered. +Moment resultant 𝑀𝑌𝑌𝐹 at failure. If zero, failure due to this +component is not considered. +Moment resultant 𝑀𝑍𝑍𝐹 at failure. If zero, failure due to this +component is not considered. +*CONSTRAINED_JOINT_STIFFNESS_OPTION_{OPTION} +Available options include: +FLEXION-TORSION +GENERALIZED +TRANSLATIONAL +If desired a description of the joint stiffness can be provided with the option: +TITLE +which is written into the d3hsp and jntforc files. +Purpose: Define optional rotational and translational joint stiffness for joints defined by +*CONSTRAINED_JOINT_OPTION. These definitions apply to all joints even though +degrees of freedom that are considered in the joint stiffness capability may be +constrained out in some joint types. The energy that is dissipated with the joint stiffness +option is written for each joint in joint force file with the default name, jntforc. In the +global energy balance this energy is included with the energy of the discrete elements, +i.e., the springs and dampers. +Card Format: +The optional TITLE card and card 1 are common to all joint stiffness types. +Cards 2 to 4 are unique for each stiffness type. +Title Card. Additional card for the TITLE keyword option. + Optional +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +TITLE +A80 +Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +JSID +PIDA +PIDB +CIDA +CIDB +JID +Type +I +I +I +I +I +I +Default +none +none +none +none +CIDA +none + VARIABLE +DESCRIPTION +TITLE +Description of joint stiffness for output files jntforc and d3hsp. +JSID +PIDA +PIDB +CIDA +CIDB +Joint stiffness ID +Part ID for rigid body A, see *PART. +Part ID for rigid body B, see *PART. +Coordinate ID for rigid body A, see *DEFINE_COORDINATE_- +OPTION. For the translational stiffness the local coordinate +system must be defined by nodal points, *DEFINE_COORDI- +NATE_NODES, since the first nodal point in each coordinate +system is used to track the motion. +Coordinate ID for rigid body B. If zero, the coordinate ID for +rigid body A is used, see *DEFINE_COORDINATE_OPTION. +For the translational stiffness the local coordinate system must be +defined by nodal points, *DEFINE_COORDINATE_NODES, +since the first nodal point in each coordinate system is used to +track the motion. +JID +Joint ID for the joint reaction forces. If zero, tables can’t be used +in place of load curves for defining the frictional moments. +Card 2 for FLEXION-TORSION option. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCIDAL +LCIDG +LCIDBT DLCIDAL DLCIDG DLCIDBT +Type +I +I +I +I +I +I +Default +none +1.0 +none +none +1.0 +none +Card 3 for FLEXION-TORSION option. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ESAL +FMAL +ESBT +FMBT +Type +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +Card 4 for FLEXION-TORSION option. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SAAL +NSABT +PSABT +Type +F +F +F +Default not used not used not used +Figure 10-28. The angles 𝛼, 𝛽, 𝛾 align rigid body one with rigid body two for +the FLEXION-TORSION option. + VARIABLE +LCIDAL +LCIDG +LCIDBT +DLCIDAL +DLCIDG +DESCRIPTION +Load curve ID for 𝛼-moment versus rotation in radians. See +Figure 10-28 where it should be noted that 0 ≤ 𝛼 ≤ 𝜋. If zero, the +applied moment is set to zero. See *DEFINE_CURVE. +Load curve ID for 𝛾 versus a scale factor which scales the bending +moment due to the 𝛼 rotation. This load curve should be defined +in the interval −𝜋 ≤ 𝛾 ≤ 𝜋. If zero the scale factor defaults to 1.0. +See *DEFINE_CURVE. +Load curve ID for 𝛽-torsion moment versus twist in radians. If +zero the applied twist is set to zero. See *DEFINE_CURVE. +Load curve ID for 𝛼-damping moment versus rate of rotation in +radians per unit time. If zero, damping is not considered. See +*DEFINE_CURVE. +Load curve ID for 𝛾-damping scale factor versus rate of rotation +in radians per unit time. This scale factor scales the 𝛼-damping +moment. If zero, the scale factor defaults to one. See *DEFINE_- +CURVE. +DLCIDBT +Load curve ID for 𝛽-damping torque versus rate of twist. If zero +damping is not considered. See *DEFINE_CURVE. +z1 +z2 +y2 +x1 +y1 +x2 +Figure 10-29. Flexion-torsion joint angles. If the initial positions of the local +coordinate axes of the two rigid bodies connected by the joint do not coincide, +the angles, 𝛼 and 𝛾, are initialized and torques will develop instantaneously +based on the defined load curves. The angle 𝛽 is also initialized but no torque +will develop about the local axis on which 𝛽 is measured. Rather, 𝛽 will be +measured relative to the computed offset. + VARIABLE +ESAL +FMAL +DESCRIPTION +Elastic stiffness per unit radian for friction and stop angles for 𝛼 +rotation. If zero, friction and stop angles are inactive for 𝛼 +rotation. See Figure 10-31. +Frictional moment limiting value for 𝛼 rotation. If zero, friction is +inactive for 𝛼 rotation. This option may also be thought of as an +elastic-plastic spring. If a negative value is input then the +absolute value is taken as the load curve or table ID defining the +yield moment versus 𝛼 rotation. A table permits the moment to +also be a function of the joint reaction force and requires the +specification of JID on Card 1. See Figure 10-31. +VARIABLE +DESCRIPTION +ESBT +FMBT +Elastic stiffness per unit radian for friction and stop angles for 𝛽 +twist. If zero, friction and stop angles are inactive for 𝛽 twist. +Frictional moment limiting value for 𝛽 twist. If zero, friction is +inactive for 𝛽 twist. This option may also be thought of as an +elastic-plastic spring. If a negative value is input then the +absolute value is taken as the load curve or table ID defining the +yield moment versus 𝛽 rotation. A table permits the moment to +also be a function of the joint reaction force and requires the +specification of JID on Card 1. +SAAL +Stop angle in degrees for 𝛼 rotation where 0 ≤ 𝛼 ≤ 𝜋. Ignored if +zero. See Figure 10-31. +NSABT +Stop angle in degrees for negative 𝛽 rotation. Ignored if zero. +PSABT +Stop angle in degrees for positive 𝛽 rotation. Ignored if zero. +Remarks: +This option simulates a flexion-torsion behavior of a joint in a slightly different fashion +than with the generalized joint option. +After the stop angles are reached the torques increase linearly to resist further angular +motion using the stiffness values on Card 3. If the stiffness value is too low or zero, the +stop will be violated. +The moment resultants generated from the moment versus rotation curve, damping +moment versus rate-of-rotation curve, and friction are evaluated independently and are +added together. +Card 2 for GENERALIZED stiffness option. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCIDPH +LCIDT +LCIDPS DLCIDPH DLCIDT DLCIDPS +Type +I +I +I +I +I +I +Default +none +none +none +none +none +none +Figure 10-30. Definition of angles for the GENERALIZED joint stiffness. +Card 3 for GENERALIZED stiffness option. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ESPH +FMPH +EST +FMT +ESPS +FMPS +Type +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Card 4 for GENERALIZED stiffness option. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NSAPH +PSAPH +NSAT +PSAT +NSAPS +PSAPS +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +Case I: Elastic Perfectly Plastic Yield Curve +Case II: Load Curve Used for Yield Curve +friction +value +elastic +stiffness +load curve +Displacement +negative stop +displacement +Displacement +positive stop +displacement +negative stop +negative stop +displacement +displacement +positive stop +positive stop +displacement +displacement +Yield curve beyond stop angle +Yield curve +Example loading/unloading path +load curve +reflection +Figure 10-31. Friction model. The friction model is motivated by plasticity and +it is implemented for both rotational and translational joints. In the context of +a rotational joint, the y-axis is to be interpreted as moment (rotational force) +and the x-axis is to be interpreted as rotation. Case I (left) is activated by a +positive friction value. Case II (right) is activated by a negative integer friction +value, the absolute value of which specifies a load curve. See the friction, elastic, +and stop angle/displacement parameters from the input cards (FM[var], ES[var], +NSA[var], PSA[var]). + VARIABLE +LCIDPH +LCIDT +LCIDPS +DLCIDPH +DLCIDT +DESCRIPTION +Load curve ID for 𝜙-moment versus rotation in radians. See +Figure 10-30. If zero, the applied moment is set to 0.0. See *DE- +FINE_CURVE. +Load curve ID for 𝜃-moment versus rotation in radians. If zero, +the applied moment is set to 0.0. See *DEFINE_CURVE. +Load curve ID for 𝜓-moment versus rotation in radians. If zero, +the applied moment is set to 0.0. See *DEFINE_CURVE. +Load curve ID for 𝜙-damping moment versus rate of rotation in +radians per unit time. If zero, damping is not considered. See +*DEFINE_CURVE. +Load curve ID for 𝜃-damping moment versus rate of rotation in +radians per unit time. If zero, damping is not considered. See +*DEFINE_CURVE. +VARIABLE +DLCIDPS +ESPH +FMPH +EST +FMT +ESPS +FMPS +DESCRIPTION +Load curve ID for 𝜓-damping torque versus rate of rotation in +radians per unit time. If zero, damping is not considered. See +*DEFINE_CURVE. +Elastic stiffness per unit radian for friction and stop angles for 𝜙 +rotation. If zero, friction and stop angles are inactive for 𝜙 +rotation. +Frictional moment limiting value for 𝜙 rotation. If zero, friction is +inactive for 𝜙 rotation. This option may also be thought of as an +elastic-plastic spring. If a negative value is input then the +absolute value is taken as the load curve or table ID defining the +yield moment versus 𝜙 rotation. A table permits the moment to +also be a function of the joint reaction force and requires the +specification of JID on card 1. See Figure 10-31. +Elastic stiffness per unit radian for friction and stop angles for 𝜃 +rotation. If zero, friction and stop angles are inactive for 𝜃 +rotation. See Figure 10-31. +Frictional moment limiting value for 𝜃 rotation. If zero, friction is +inactive for 𝜃 rotation. This option may also be thought of as an +elastic-plastic spring. If a negative value is input then the +absolute value is taken as the load curve or table ID defining the +yield moment versus 𝜃 rotation. A table permits the moment to +also be a function of the joint reaction force and requires the +specification of JID on card 1. +Elastic stiffness per unit radian for friction and stop angles for 𝜓 +rotation. If zero, friction and stop angles are inactive for 𝜓 +rotation. +Frictional moment limiting value for 𝜓 rotation. If zero, friction is +inactive for 𝜓 rotation. This option may also be thought of as an +elastic-plastic spring. If a negative value is input then the +absolute value is taken as the load curve or table ID defining the +yield moment versus 𝜓 rotation. A table permits the moment to +also be a function of the joint reaction force and requires the +specification of JID on card 1. +NSAPH +Stop angle in degrees for negative 𝜙 rotation. Ignored if zero. See +Figure 10-31. +PSAPH +Stop angle in degrees for positive 𝜙 rotation. Ignored if zero. +VARIABLE +DESCRIPTION +NSAT +PSAT +Stop angle in degrees for negative 𝜃 rotation. Ignored if zero. +Stop angle in degrees for positive 𝜃 rotation. Ignored if zero. +NSAPS +Stop angle in degrees for negative 𝜓 rotation. Ignored if zero. +PSAPS +Stop angle in degrees for positive 𝜓 rotation. Ignored if zero. +Remarks: +After the stop angles are reached the torques increase linearly to resist further angular +motion using the stiffness values on Card 3. Reasonable stiffness values have to be +chosen. If the stiffness values are too low or zero, the stop will be violated. +If the initial local coordinate axes do not coincide, the angles, 𝜙, 𝜃, and 𝜓, will be +initialized and torques will develop instantaneously based on the defined moment vs. +rotation curves. +There are two methods available to calculate the rotation angles between the coordinate +systems. For more information, see the JNTF parameter on *CONTROL_RIGID. +Card 2 for TRANSLATIONAL stiffness option. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCIDX +LCIDY +LCIDZ +DLCIDX +DLCIDY +DLCIDZ +Type +I +I +I +I +I +I +Default +none +none +none +none +none +none +Card 3 TRANSLATIONAL stiffness option. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ESX +FFX +ESY +FFY +ESZ +FFZ +Type +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Card 4 for TRANSLATIONAL stiffness option. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NSDX +PSDX +NSDY +PSDY +NSDZ +PSDZ +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 + VARIABLE +LCIDX +LCIDY +LCIDZ +DLCIDX +DESCRIPTION +Load curve ID for x-force versus x-distance between the origins of +CIDA and CIDB based on the x-direction of CIDB. If zero, the +applied force is set to 0.0. See *DEFINE_CURVE. +Load curve ID for y-force versus y-distance between the origins of +CIDA and CIDB based on the y-direction of CIDB. If zero, the +applied force is set to 0.0. See *DEFINE_CURVE. +Load curve ID for z-force versus z-distance between the origins of +CIDA and CIDB based on the z-direction of CIDB. If zero, the +applied force is set to 0.0. See *DEFINE_CURVE. +Load curve ID for x-damping force versus rate of x-translational +displacement per unit time between the origins of CIDA and +CIDB based on the x-direction of CIDB. If zero, damping is not +considered. See *DEFINE_CURVE. +VARIABLE +DLCIDY +DLCIDZ +ESX +FFX +ESY +FFY +ESZ +FMZ +DESCRIPTION +Load curve ID for y-damping force versus rate of y-translational +displacement per unit time between the origins of CIDA and +CIDB based on the y-direction of CIDB. If zero, damping is not +considered. See *DEFINE_CURVE. +Load curve ID for z-damping force versus rate of z-translational +displacement per unit time between the origins of CIDA and +CIDB based on the z-direction of CIDB. If zero, damping is not +considered. See *DEFINE_CURVE. +Elastic stiffness for friction and stop displacement for x- +translation. If zero, friction and stop angles are inactive for x- +translation. See Figure 10-31. +Frictional force limiting value for x-translation. If zero, friction is +inactive for x-translation. This option may also be thought of as +an elastic-plastic spring. If a negative value is input then the +absolute value is taken as the load curve ID defining the yield +force versus x-translation. See Figure 10-31. +Elastic stiffness for friction and stop displacement for y- +translation. If zero, friction and stop angles are inactive for y- +translation. +Frictional force limiting value for y-translation. If zero, friction is +inactive for y-translation. This option may also be thought of as +an elastic-plastic spring. If a negative value is input then the +absolute value is taken as the load curve ID defining the yield +force versus y-translation. +Elastic stiffness for friction and stop displacement for z- +translation. If zero, friction and stop angles are inactive for z- +translation. +Frictional force limiting value for z-translation. If zero, friction is +inactive for z-translation. This option may also be thought of as +an elastic-plastic spring. If a negative value is input then the +absolute value is taken as the load curve ID defining the yield +force versus z-translation. +NSDX +Stop displacement for negative x-translation. Ignored if zero. See +Figure 10-31. +PSDX +Stop displacement for positive x-translation. Ignored if zero. +VARIABLE +DESCRIPTION +Stop displacement for negative y-translation. Ignored if zero. +Stop displacement for positive y-translation. Ignored if zero. +Stop displacement for negative z-translation. Ignored if zero. +Stop displacement for positive z-translation. Ignored if zero. +NSDY +PSDY +NSDZ +PSDZ +Remarks: +After the stop displacements are reached the force increases linearly to resist further +translational motion using the stiffness values on Card 3. Reasonable stiffness values +must be chosen. If the stiffness values are too low or zero, the stop will be violated. +Example: +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *CONSTRAINED_JOINT_STIFFNESS_GENERALIZED +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Define a joint stiffness for the revolute joint described in +$ *CONSTRAINED_JOINT_REVOLUTE +$ +$ Attributes of the joint stiffness: +$ - Used for defining a stop angle of 30 degrees rotation +$ (i.e., the joint allows a positive rotation of 30 degrees and +$ then imparts an elastic stiffness to prevent further rotation) +$ - Define between rigid body A (part 1) and rigid body B (part 2) +$ - Define a local coordinate system such that local x corresponds +$ to the joint’s axis of revolution and the angle phi is the angle +$ of rotation about that axis. +$ - The elastic stiffness per unit radian for the stop angle is 100. +$ - Variables left blank are not used during the simulation. +$ +*CONSTRAINED_JOINT_STIFFNESS_GENERALIZED +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ jsid pida pidb cida cidb + 1 1 2 5 5 +$ +$ lcidph lcidt lcidps dlcidph dlcidt dlcidps +$ +$ esph fmps est fmt esps fmps + 100.0 +$ +$ nsaph psaph nsat psat nsaps psaps + 30.0 +$ +$ +*DEFINE_COORDINATE_NODES +$ cid n1 n2 n3 +5 1 2 3 +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +*CONSTRAINED_JOINT_USER_FORCE +Purpose: Define input data for a user subroutine to generate force resultants as a +function of time and joint motion. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FID +JID +NHISV +Type +I +I +Default +none +none +I +0 +User Subroutine Constants Cards. Define up to 48 optional user constants (6 cards +total) for the user subroutine. This input is terminated after 48 constants are defined +or when the next “*” keyword card is encountered. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CONST1 CONST2 CONST3 CONST4 CONST5 CONST6 CONST7 CONST8 +Type +F +F +F +F +F +I +I +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +FID +JID +NHISV +Joint user force ID. +Joint ID for which this user force input applies. +Number of history variables required for this definition. An array +NHISV long is allocated and passed into the user subroutine. +This array is updated in the user subroutine. +CONSTn +A constant which is passed into the user subroutine. +*CONSTRAINED_LAGRANGE_IN_SOLID_{OPTION1}_{OPTION2} +Purpose: This command provides the coupling mechanism for modeling Fluid- +Structure Interaction (FSI). The structure can be constructed from Lagrangian shell +and/or solid entities. The multi-material fluids are modeled by ALE formulation. +Available options for OPTION1 include: + +EDGE +This option may be used to allow the coupling between the edge of a shell part or part +set and one or more ALE multi-material groups (AMMG). It accounts for the shell +thickness in the coupling calculation. The edge thickness is the same as the shell +thickness. This option only works when the Lagrangian slave set is defined as a part or +a part set ID. It will not work for a slave segment set. One application of this option is a +simulation of a Lagrangian blade (a shell part) cutting through some ALE material. +Available options for OPTION2 include: + +TITLE +To define a coupling (card) ID number and title for each coupling card. If a title is not +defined LS-DYNA will automatically create an internal title for this coupling definition. +The ID number can be used to delete coupling action in a restart input deck via the +*DELETE_FSI card. +Title Card. Additional card for the TITLE keyword option. + Optional +1 +2 +3 +4 +5 +6 +7 +8 +Variable +COUPID +Type +I +TITLE +A70 +Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SLAVE MASTER +SSTYP +MSTYP +NQUAD +CTYPE +DIREC +MCOUP +Type +I +I +Default +none +none + Card 2 +1 +2 +I +0 +3 +I +0 +4 +I +0 +5 +I +2 +6 +I +1 +7 +I +0 +8 +Variable +START +END +PFAC +FRIC +FRCMIN +NORM NORMTYP DAMP +Type +Default + Card 3 +Variable +Type +F +0 +1 +K +F +F +F +F +F +1.0E10 +0.1 +0.0 +0.5 +2 +3 +4 +5 +I +0 +6 +I +0 +7 +F +0.0 +8 +HMIN +HMAX +ILEAK +PLEAK +LCIDPOR +NVENT +IBLOCK +Default +0.0 +none +none +F +F +I +0 +F +0.1 +I +0 +I +0 +I +0 +Card 4a. This card is required for CTYPE 11 & 12 but is otherwise optional. + Card 4a +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IBOXID +IPENCHK +INTFORC +IALESOF +LAGMUL PFACMM +THKF +Type +Default +I +0 +I +0 +I +0 +I +0 +F +0.0 +I +0 +F +0.0 +Porous Coupling Card 4b. This card applies only to CTYPE 11 & 12. If 4b is defined, +4a must be defined before 4b. + Card 4b +Variable +1 +A1 +Type +F +2 +B1 +F +3 +A2 +F +4 +B2 +F +5 +A3 +F +6 +B3 +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +7 +8 +POREINI +F +0.0 +Venting Geometry Card(s) 4c. These card(s) set venting geometry. It is repeated +NVENT times (one card for defining each vent hole). It is defined only if NVENT > 0 in +card 3. The last NVENT cards for *CONSTRAINED_LAGRANGE_IN_SOLID are taken +to be Card(s) 4c, therefore, Cards 4a and 4b are not mandatory when Card(s) 4c are +defined. + Card 4c +1 +2 +3 +4 +5 +6 +7 +8 +Variable +VENTSID +VENTYP +VTCOEF POPPRES +COEFLC +Type +Default +I +0 +I +0 +I +0 +F +0.0 +I +0 + VARIABLE +COUPID +DESCRIPTION +Coupling (card) ID number. This ID can be used in a restart input +deck to delete or reactivate this coupling action via the +*DELETE_FSI card. If not defined, LSDYNA will assign an +internal coupling ID based on the order of appearance in the +input deck. +TITLE +A description of this coupling definition (A70). +SLAVE +Slave set ID defining a part, part set or segment set ID of the +Lagrangian or slave structure . See Remark 1. +MASTER +Master set ID defining a part or part set ID of the ALE or master +solid elements . +VARIABLE +DESCRIPTION +SSTYP +Slave set type of “SLAVE” : +EQ.0: part set ID (PSID). +EQ.1: part ID (PID). +EQ.2: segment set ID (SGSID). +MSTYP +Master set type of “MASTER” : +EQ.0: part set ID (PSID). +EQ.1: part ID (PID). +NQUAD +Number of coupling points distributed over each coupled +Lagrangian surface segment. +EQ.0: NQUAD will be set by default to 2, +GT.0: An NQUAD × NQUAD coupling points distribution +over each Lagrangian segment is defined, +LT.0: NQUAD is reset to a positive value. Coupling at nodes +is obsolete. +CTYPE +Fluid-Structure coupling method. The constraint methods (1, 2, +and 3) are not supported in MPP. +EQ.1: constrained acceleration. +EQ.2: constrained acceleration and velocity (default, see +Remark 3). +EQ.3: constrained acceleration and velocity, normal direction +only. +EQ.4: penalty coupling for shell (with or without erosion) and +solid elements (without erosion). +NOTE: For RIGID slave PARTS a penalty cou- +pling method (CTYPE=4) must be used, +see parameter CTYPE below. +EQ.5: penalty coupling allowing erosion in the Lagrangian +entities (solid elements and thick shells). +EQ.6: penalty coupling designed for airbag modeling which +automatically controls the DIREC parameter internally. +It is equivalent to setting {CTYPE = 4; DIREC = 1} for +unfolded region; and {CTYPE = 4; DIREC = 2}; in fold- +VARIABLE +DESCRIPTION +ed region. For both cases: {ILEAK = 2; FRCMIN = 0.3}. +EQ.11: coupling designed to couple Lagrangian porous shell to +ALE material. When this option is used, THKF, the 7th +column parameter of optional card 4a and the first 2 +parameters of optional card 4b must be defined. See +*LOAD_BODY_POROUS and remark 13 below. +EQ.12: coupling designed to couple Lagrangian porous solid +to ALE material. When this option is used, Ai & Bi pa- +rameters of optional card 4b must be defined (card 4a +must be defined but can be blank). See *LOAD_- +BODY_POROUS and Remark 14 below +DIREC +For CTYPE=4, 5, or 6 +Coupling direction: +EQ.1: normal direction, compression and tension (default) +EQ.2: normal direction, compression only +EQ.3: all directions +For CTYPE=12 +Flag to activate an element coordinate system: +EQ.0: The forces are applied in the global directions. +EQ.1: The forces are applied in a local system attached to the +Lagrangian solid. +is consistent with + The system +AOPT = 1 in *LOAD_BODY_POROUS. . +MCOUP +For CTYPE = 4, 5, 6, 11, or 12 +Multi-material option: +EQ.0: couple with all multi-material groups, +EQ.1: couple with material with highest density. +LT.0: MCOUP must be an integer. -MCOUP refers to a set ID +of an ALE multi-material group. See *SET_MULTI-MA- +TERIAL_GROUP. +START +Start time for coupling. +END +End time for coupling. If less than zero, coupling will be turned +off during dynamic relaxation. After dynamic relaxation phase is +finished, the absolute value will be taken as end time. +VARIABLE +PFAC +DESCRIPTION +For CTYPE = 4,5 or 6 +Penalty factor. PFAC is a scale factor for scaling the estimated +stiffness of the interacting (coupling) system. It is used to +compute the coupling forces to be distributed on the slave and +master parts +GT.0: Fraction of estimated critical stiffness. +LT.0: PFAC must be an integer, and -PFAC is a load curve ID. +The curve defines the coupling pressure on the y-axis as +a function of the penetration along the x-axis. +For CTYPE = 11 or 12 +Time step factor +FRIC +Coefficient of friction (used with DIREC = 1 and 2 only). +FRCMIN +Minimum volume fraction of a coupled ALE multi-material +group (AMMG) or fluid in a multi-material ALE element to +activate coupling. Default value is 0.5. Reducing FRCMIN +(typically, between 0.1 and 0.3) would turn on coupling earlier to +prevent leakage in high velocity impact cases. +NORM +A Lagrangian segment will couple to fluid on only one side of the +segment. NORM determines which side. See Remark 6. +EQ.0: Couple to fluid (AMMG) on head-side of Lagrangian +segment normal vector. +EQ.1: Couple to fluid (AMMG) on tail-side of Lagrangian +segment normal vector. +NORMTYP +Penalty coupling spring (or force) direction (DIREC = 1, or 2): +EQ.0: normal vectors are interpolated from nodal normals. +(default). +EQ.1: normal vectors are interpolated from segment normals. +This is sometimes a little more robust for sharp Lagran- +gian corners, and folds. +DAMP +Damping factor for penalty coupling. This is a coupling-damping +scaling factor. Typically it may be between 0 and 1 . +VARIABLE +DESCRIPTION +K +HMIN +Thermal conductivity of a virtual fluid between the slave surface +and the master material . +The absolute value is minimum air gap in heat transfer, ℎmin . +LT.0: turn on constraint based thermal nodal coupling +between LAG structure and ALE fluids. +GE.0: minimum air gap. If zero, default to 1.0e-6. +HMAX +Maximum air gap in heat transfer, ℎmax. There is no heat transfer +above this value . +ILEAK +Coupling leakage control flag (Remark 9): +EQ.0: none (default), +EQ.1: weak, leakage control is turned off if +penetrating volume fraction > FRCMIN + 0.2 +EQ.2: strong, with improved energy consideration. Leakage +control is turned off if +penetrating volume fraction > FRCMIN + 0.4 +PLEAK +Leakage control penalty factor, 0 < PLEAK < 0.2 is recommended. +This factor influences the additional coupling force magnitude to +prevent leakage. It is conceptually similar to PFAC. Almost +always, the default value (0.1) is adequate. +LCIDPOR +If this is a positive integer: A load curve ID (LCID) defining +porous flow through coupling segment: +Abscissa = 𝑥 = (𝑃up − 𝑃down) +Ordinate = 𝑦 = relative porous fluid velocity +Where Pup and Pdown are, respectively, the upstream and +downstream pressures across of the porous coupling segment. +The relative porous velocity is the ALE fluid velocity relative to +the moving Lagrangian segment. This experimental data curve +must be provided by the user. +If LCIDPOR is a negative integer: The porous flow is controlled +by the parameters FLC, FAC, ELA under *MAT_FABRIC card. +VARIABLE +DESCRIPTION +CAUTION: The pressure under the FAC load curve is +“absolute upstream pressure” . +Abscissa = 𝑥 = absolute upstream pressure +Ordinate = 𝑦 = relative porous fluid velocity +For CTYPE = 11 or CTYPE = 12 and POREINI = 0.0: +LT.0: The load curve |LCIDPOR| is a factor versus time of the +porous force computed by the Ergun equation . +GT.0: The load curve LCIDPOR is a porous force versus +velocity, which replaces the force computed by the +Ergun equation . +For CTYPE = 11 or CTYPE = 12 and POREINI > 0.0: +NE.0: The load curve |LCIDPOR| is a factor versus time of the +porous force computed by the Ergun equation . +The number of vent surface areas to be defined. Each venting +flow surface is represented by one or more Lagrangian segments +(or surfaces). +For airbag applications, this may be referred to as “isentropic” +venting where the isentropic flow equation is used to compute +the mass flow rate based on the ratio of the upstream and +downstream pressures 𝑃up/𝑃down. +For each of the NVENT vent surfaces, an additional card of +format 4c defining the geometrical and flow properties for each +vent surface will be read in. +The vented mass will simply be deleted from the system and +cannot be visualized as in the case of physical venting . +NVENT +VARIABLE +IBLOCK +DESCRIPTION +Flag to control the venting (or porous) flow blockage due to +Lagrangian contact during ALE computation. +EQ.0: Off +EQ.1: On +The venting definition is defined in this command. However, the +venting flow may be defined via either the LCIDPOR parameter +in this command or via the *MAT_FABRIC parameters (FLC, +FAC, ELA). However, note that FVOPT (blocking) parameter +under *MAT_FABRIC applies only to CV computation. +IBOXID +A box ID defining a box region in space in which ALE coupling is +activated. +GT.0: At time = 0.0, the Lagrangian segments inside this box +are remembered. In subsequent coupling computation +steps, there is no need to search for the Lagrangian seg- +ments again. +LT.0: At each FSI bucketsort, the Lagrangian segments inside +this box are marked as active coupling segments. This +makes the coupling operate more efficiently when struc- +ture mesh is approaching ALE domain, i.e. hydroplan- +ing, bird strike, etc. +IPENCHK +Only for CTYPE = 4 +Initial penetration check flag : +EQ.0: Do not check for initial penetration. +EQ.1: Check and save initial ALE material penetration across a +Lagrangian surface (d0), but do not activate coupling at +t = 0. In subsequent steps (t > 0) the actual penetration is +computed as follows: +Actual Penetration +⏟⏟⏟⏟⏟⏟⏟⏟⏟ +𝑑𝑎 += Total Penetration +⏟⏟⏟⏟⏟⏟⏟⏟⏟ +𝑑𝑇 +− Initial Penetration +⏟⏟⏟⏟⏟⏟⏟⏟⏟ +𝑑0 +INTFORC +A flag to turn on or off the output of ALE coupling pressure and +forces on the slave Lagrangian segments (or surfaces). +EQ.0: Off +EQ.1: On +Note that the coupling pressures and forces are computed based +VARIABLE +DESCRIPTION +on the coupling stiffness reponse to the ALE fluid penetration. +When INFORC = 1 and a *DATABASE_BINARY_FSIFOR (DBF) +card is defined, LS-DYNA writes out the segment coupling +pressure and forces to the binary interface force file for contour +plotting. This interface force file must be given a name on the +execution line, for example: +ls-dyna i=inputfilename.k … h=interfaceforcefilename +The time interval between output is defined by “dt” in the DBF +card. To plot the binary data in this file: +ls-prepost interfaceforcefilename +IALESOF +An integer flag to turn ON/OFF a supplemental Lagrange +multiplier FSI constraint which provides a coupling force in +addition to the basic penalty coupling contribution. This is a +hybrid coupling method. +EQ.0: OFF (default). +EQ.1: Turn ON the hybrid Lagrange-multiplier method. +LAGMUL multiplier factor is read. +LAGMUL +A Lagrange multiplier factor with a range between 0.0 and 0.05 +may be defined. A typical value may be 0.01. This should never +be greater than 0.1. +EQ.0: OFF (default). +GT.0: Turn ON the Lagrange-multiplier method and use +LAGMUL as a coefficient for scaling the penalty factor. +PFACMM +Mass-based penalty stiffness factor computational options. This +works in conjunction with PFAC = constant (not a load curve). +The coupling penalty stiffness (CPS) is computed based on an +estimated effective coupling mass. +EQ.0: CPS ∝ PFAC × min (𝑚slave, 𝑚master) , default. +EQ.1: CPS ∝ PFAC × max (𝑚slave, 𝑚master) . +EQ.2: CPS ∝ PFAC × √𝑚slave𝑚master , geometric-mean of the +masses. +EQ.3: CPS ∝ PFAC × 𝐾Lagrangian where K is the bulk modulus +of the slave or Lagrangian part +VARIABLE +THKF +DESCRIPTION +For all CTYPE choices except 11: +A flag to account for the coupling thickness of the Lagrangian +shell (slave) part. +LT.0: Use positive value of |THKF| for coupling segment +thickness. +EQ.0: Do not consider coupling segment thickness. +GT.0: Coupling segment thickness scale factor. +For CTYPE = 11: +This thickness is required for volume calculation. +GT.0: (Fabric) Thickness scale factor. The base shell thickness +is taken from the *PART definition. +LT.0: User-defined (Fabric) thickness. The fabric thickness is +set to |THKF|. +A1 +Viscous coefficient for the porous flow Ergun equation . +GT.0: +For CTYPE = 11 +which is the coefficient for normal-to-segment direction. +A1 = 𝐴𝑛 +For CTYPE = 12 +A1 = 𝐴𝑥 +which is the coefficient for the x-direction in the +coordinate system specified by DIREC. +LT.0: If POREINI = 0.0, the coefficient is time dependent +through a load curve id defined by |A1|. If POREI- +NI > 0.0, the coefficient is porosity dependent through a +load curve id defined by |A1|. The porosity is defined +by PORE . +B1 +Inertial coefficient for the porous flow Ergun equation . +GT.0: +For CTYPE = 11 +B1 = 𝐵𝑛 +VARIABLE +DESCRIPTION +A2 +B2 +which is the coefficient for normal-to-segment direction. +For CTYPE = 12 +B1 = 𝐵𝑥 +which is the coefficient for the x-direction of a coordinate +system specified by DIREC. +LT.0: If POREINI = 0.0, the coefficient is time dependent +through a load curve id defined by |B1|. If POREI- +NI > 0.0, the coefficient is porosity dependent through a +load curve id defined by |B1|. The porosity is defined +by PORE . +For CTYPE = 12 +Viscous coefficient for the porous flow Ergun equation . +GT.0: Coefficient for the y-direction of a coordinate systems +specified by DIREC. +A2 = 𝐴𝑦 +LT.0: If POREINI = 0.0, the coefficient is time dependent +through a load curve id defined by |A1|. If POREI- +NI > 0.0, the coefficient is porosity dependent through a +load curve id defined by |A2|. The porosity is defined +by PORE . +For CTYPE=12 +Inertial coefficient for the porous flow Ergun equation . +GT.0: Coefficient for the y-direction of a coordinate system +specified by DIREC. +B2 = 𝐵𝑦 +LT.0: If POREINI = 0.0 and B2 < 0, the coefficient is time +dependent through a load curve id defined by |B2|. If +POREINI > 0.0 and B2 < 0, the coefficient is porosity +dependent through a load curve id defined by |B2|. The +porosity is defined by PORE . +A3 +For CTYPE = 12 +Viscous coefficient for the porous flow Ergun equation . +VARIABLE +DESCRIPTION +GT.0: Coefficient for the z-direction of a coordinate system +specified by DIREC. +A3 = 𝐴𝑧 +LT.0: If POREINI = 0.0 and A3 < 0, the coefficient is time +dependent through a load curve id defined by |A3|. If +POREINI > 0.0 and A3 < 0, the coefficient is porosity +dependent through a load curve id defined by |A3|. +The porosity is defined by PORE . +B3 +For CTYPE = 12 +Inertial coefficient for the porous flow Ergun equation . +GT.0: Coefficient for the z-direction of a coordinate system +specified by DIREC. +B3 = 𝐵𝑧 +LT.0: If POREINI = 0.0 and B3 < 0, the coefficient is time +dependent through a load curve id defined by |B3|. If +POREINI > 0.0 and B3 < 0, the coefficient is porosity +dependent through a load curve id defined by |B3|. +The porosity is defined by PORE . +POREINI +For CTYPE = 11 or CTYPE = 12 +POREINI is the initial volume of pores in an element. The current +volume is +PORE = POREINI × +𝑣(𝑡) +𝑣(𝑡0) +where 𝑣(𝑡) and 𝑣(𝑡0) are the current and initial element volumes +respectively. +VENTSID +Set ID of the vent hole shape. +VENTYP +Vent surface area set ID type: +EQ.0: Part set ID (PSID). +EQ.1: Part ID (PID). +EQ.2: Segment set ID (SGSID). +VTCOEF +Flow coefficient for each vent surface area. +VARIABLE +POPPRES +DESCRIPTION +Venting pop pressure limit. If the pressure inside the airbag is +lower than this pressure, then nothing is vented. Only when the +pressure inside the airbag is greater than POPPRES that venting +can begin. +COEFLC +A time-dependent multiplier load curve for correcting the vent +flow coefficient, with values ranging from 0.0 to 1.0. +Best Practices: +Due to the complexity of this card, some comments on simple, efficient and robust +coupling approach are given here. These are not rigid guidelines, but simply some +experience-based observations. +1. Definition (Fluid and Structure). The term fluid, in the Fluid-Structure +Interaction (FSI), refers to materials with ALE element formulation, not indicat- +ing the phase (solid, liquid or gas) of those materials. In fact, solid, liquid and +gas can all be modeled by the ALE formulation. The term structure refers to +materials with Lagrangian element formulation. +2. Default Values (CTYPE and MCOUP). In general, penalty coupling (CTYPE 4 +& 5) is recommended, and MCOUP=negative integer is a better choice to define +a specific ALE multi-material group (AMMG) to be coupled to the Lagrangian +surface. At the minimum, all parameters on card 1 are to be specified, and the +default values for most are good starting choices (except MCOUP). +3. How to Correct Leakage. If there is leakage, PFAC, FRCMIN, NORMTYPE +and ILEAK are the 4 parameters that can be adjusted. +a) For hard structure (steel) and very compressible fluid (air), PFAC may be +set to 0.1 (or higher). PFAC = constant value. +b) Next, keeping PFAC = constant and set PFACMM = 3 (optional card 4a). +This option scales the penalty factor by the bulk modulus of the Lagrangi- +an structure. This new approach has also shown to be effective for some +airbag application. +c) The next approach may be switching from constant PFAC to a load curve +approach (i.e. PFAC = load curve, and PFACMM = 0). By looking at the +pressure in the system near leakage original location, we can get a feel for +the pressure required to stop it. +d) If leakage persists after some iterations on the coupling force controls, one +can subsequently try to set ILEAK = 2 in combination with the other con- +trols to prevent leakage. +e) If the modifications fail to stop the leakage, maybe the meshes have to be +redesigned to allow better interactions between the Lagrangian and Ale +materials. +In the example below, the underlined parameters are usually defined parame- +ters. A full card definition is shown for reference. +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*CONSTRAINED_LAGRANGE_IN_SOLID +$ SLAVE MASTER SSTYP MSTYP NQUAD CTYPE DIREC MCOUP + 1 11 0 0 4 4 2 -123 +$ START END PFAC FRIC FRCMIN NORM NORMTYPE DAMP + 0.0 0.0 0.1 0.00 0.3 0 0 0.0 +$ CQ HMIN HMAX ILEAK PLEAK LCIDPOR NVENT IBLOCK + 0 0 0 0 0.0 0 0 0 +$4A IBOXID IPENCHK INTFORC IALESOF LAGMUL PFACMM THKF +$ 0 0 0 0 0 0 0 +$4B A1 B1 A2 B2 A3 B3 +$ 0.0 0.0 0.0 0.0 0.0 0.0 +$4C VNTSID VENTYPE VENTCOEF POPPRES COEFLCID (STYPE:0=PSID;1=PID;2=SGSID) +$ 0 0 0 0.0 0 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|...8 +Remarks: +1. Meshing. In order for a fluid-structure interaction (FSI) to occur, a Lagrangian +(structure or slave) mesh must spatially overlap with an ALE (fluid or master) +mesh. Each mesh should be defined with independent node IDs. LS-DYNA +searches for the spatial intersection of between the Lagrangian and ALE mesh- +es. Where the meshes overlap, there is a possibility that interaction may occur. +In general, SLAVE, MASTER, SSTYP and MSTYPE are required definitions for +specifying overlapping-domains coupling search. +2. Number of Coupling Points. The number of coupling points, NQUAD × +NQUAD, is distributed over the surface of each Lagrangian segment. General- +ly, 2 or 3 coupling points per each Eulerian/ALE element width is adequate. +Consequently, the appropriate NQUAD values must be estimated based on the +relative resolutions between the Lagrangian and ALE meshes. +For example, if 1 Lagrangian shell element spans 2 ALE elements, Then +NQUAD for each Lagrangian segment should be 4 or 6. Alternatively, if 2 or 3 +Lagrangian segments span 1 ALE element, then maybe NQUAD = 1 would be +adequate. +If either mesh compresses or expands during the interaction, the number of +coupling points per ALE element will also change. The user must account for +this and try to maintain at least 2 coupling points per each ALE element side +length during the whole process to prevent leakage. Too many coupling points +can result in instability, and not enough can result in leakage. +3. The Constraint Method. The constraint method violates kinetic energy +balance. + The penalty method is therefore recommended. Historically, +CTYPE=2 was sometimes used to couple Lagrangian beam nodes to ALE or +Lagrangian solids, e.g., for modeling rebar in concrete, or tire cords in rubber. +solids, +For +*CONSTRAINED_BEAM_IN_SOLID is now preferred. +constraint-based +coupling +beams +such +in +of +4. Coupling Direction. DIREC=2 (compression only) may be generally a more +stable and robust choice for coupling direction. However, the physics of the +problem should dictate the coupling direction. DIREC=1 couples under both +tension and compression. This is sometimes useful; for example, in the case of a +suddenly accelerating liquid in a container. DIREC=3 is rarely appropriate +because it models an extremely sticky fluid. +5. Multi-material Coupling Option. When MCOUP is a negative integer; for +example MCOUP= -123, then an ALE multi-material set-ID (AMMSID) of 123 +must exist. This is an ID defined by a *SET_MULTI-MATERIAL_GROUP_LIST +card. This generally seems to be a better approach to couple to a specific set of +AMMGs, and have a clearly defined fluid interface interacting with a Lagrangi- +an surface. That way, any leakage may be visualized and the penalty force can +be computed more precisely. +The Couple to all materials option as activated by MCOUP = 0 is generally not +recommended. LS-DYNA calculates the fluid coupling interface as the surface +where the sum of coupled ALE materials occupies a volume fraction (Vf) equal +to 50%. Since MCOUP = 0 couples to all materials, the sum of all coupled ALE +materials is, in this case, trivially 100%. Consequently, when MCOUP = 0 there +will not be a fluid interface with which to track leakage. +Shell +Shell normal vector +Shell normal vector +Fluid +Fluid & Shell +will interact +Shell Motion +Void +Shell Motion +Fluid +Shell +Void +Fluid & Shell will +not interact, use +NORM = 1 to +reverse the vector +Shell normal vector +Shell normal vector +Figure 10-32. Shell Motion +6. Normal Vector Direction. The normal vectors (NV) of a Lagrangian shell part +are defined by the order of the nodes in *ELEMENT definitions, via the right +hand rule, and for a segment set, the order of nodes defined in *SET_SEG- +MENT. Let the side pointed to by NV be “positive”. The penalty method +measure penetration as the distance the ALE fluid penetrates from the positive +side to the negative side of the Lagrangian segment. Only fluid on the positive +side will be “seen” and coupled to. +Therefore, all normal vectors of the Lagrangian segments should point uniform- +ly toward the ALE fluid(s), AMMGs, to be coupled to. If NV point uniformly +away from the fluid, coupling is not activated. In this case, coupling can be +activated by setting NORM = 1. Sometimes a shell part or mesh is generated +such that its normal vectors do not point uniformly in a consistent direction (all +toward the inside or outside of a container, etc.) The user should always check +for the normal vectors of any Lagrangian shell part interacting with any fluid. +The NORM parameter may be used to flip the normal direction of all the seg- +ments included in the Lagrangian slave set. See Figure 10-32. +7. Coupling-Damping Factor. The user-input coupling-damping factor (DAMP) +is used to scale down the critical-damping force (~ damper constant × velocity). +For a mass-to-rigid-wall system connected by a parallel-spring-damper con- +nector, we can obtain solution for a critically-damped case. DAMP is a factor +for scaling down the amount of damping, with DAMP=1 being a critically- +damped case. +8. Heat Transfer. The method used is similar to that done by *CONTACT_…_ +THERMAL_… card, except radiation heat transfer is not considered. A gap, 𝑙, +is assumed to exist between the 2 materials undergoing heat transfer (one is +Lagrangian and the other ALE). The convection heat transfer in the gap is as- +sumed to approach simple conduction across the medium in the gap. +𝑞 = 𝐾 +𝑑𝑇 +𝑑𝑥 +~ℎΔ𝑇 ⇒ ℎ~ +The heat flux is typically defined as an energy transfer rate per unit area, +𝑞 ∼ [ 𝐽 𝑠 ⁄ ] +𝑚2 . The constant K is the thermal conductivity of the material in the gap; +ℎ, is the equivalent convection heat transfer coefficient; and Δ𝑇 is the tempera- +ture difference between the master and slave sides. There are 3 possible scenar- +ios: +ℎ~ +⎧ +{ +{ +{ +{ +{ +⎨ +{ +{ +{ +{ +{ +⎩ +𝑙⁄ +⁄ +HMIN +HMAX < 𝑙 +HMIN ≤ 𝑙 ≤ HMAX +0 < 𝑙 < HMIN +The ALE fluid must be modelled using the ALE single material with void ele- +ment formulation (ELFORM = 12) because the LS-DYNA thermal solver sup- +ports only one temperature per node. However, a workaround enables partial +support for ELFORM =11. Rather than using the thermal solver’s nodal tem- +perature field, the ALE temperature is derived from element’s internal energy +using the heat capacity. The heat is then extracted from or added to the internal +energy of ALE elements. This feature was implemented to calculate the heat +exchange between a gas mixture, modeled with *MAT_GAS_MIXTURE and +ALE multi-material formulation ELFORM = 11, and a Lagrangian container. +HMIN < 0 turns on constraint-based thermal nodal coupling between the La- +grangian surface nodes and ALE fluid nodes. This option only works with ALE +single material with void element formulation (ELFORM = 12). Once a Lagran- +gian surface node is in contact with ALE fluid (gap = 0), the heat transfer de- +scribed above is turned off. Instead the Lagrangian surface node temperature is +constrained to the ALE fluid temperature field. +9. Leakage Control. The dominate force preventing leakage across a coupled +Lagrangian surface should be the penalty associated with the coupling. Forces +from the leakage control algorithm feature should be secondary. The *DATA- +BASE_FSI keyword controls the “dbfsi” file, which reports both the coupling +forces and the leakage control force contribution. It is useful for debugging and +fine-tuning. +ILEAK = 2 conserves energy; thus, it is better for airbag applications. Leakage +control should only be enabled when (1) coupling to a specific AMMG +(MCOUP as a negative integer) is activated, and (2) the fluid interface is clearly +defined and tracked through the *ALE_MULTI-MATERIAL_GROUP card. +10. Pressure Definition in Porous Flow. There are currently two methods to +model porous flow across a Lagrangian shell structure. Both methods involve +defining an empirical data curve of relative porous gas velocity as a function of +system pressure. However the pressure definitions are slightly different de- +pending on the choice of parameter defined: +a) When porous flow is modelled using the LCIDPOR parameter (part of this +keyword), the velocity response curve expected to be given in terms of the +pressure difference: 𝑃upstream − 𝑃downstream. +b) When LCIDPOR is negative, porous flow is modelled using the *MAT_- +FABRIC material model. The FAC field in *MAT_FABRIC contains a load +curve ID given in terms of absolute upstream pressure, rather than in +terms of the pressure difference. +The *AIRBAG_ALE keyword assumes that the curve referenced by FAC in +*MAT_FABRIC is given in terms of absolute upstream pressure. These absolute +pressure data are required for the CV phase. During the ALE phase, LS-DYNA +automatically shifts the FAC curve left (negative) by 1 atmospheric pressure for +the porous coupling calculation, which uses gauge pressure, rather than abso- +lute pressure. +The mass flowing across a porous Lagrangian surface can be tracked by the +“pleak” parameter of the optional “dbfsi” ASCII output file, which may be +enabled with the *DATABASE_FSI keyword. +11. Venting. There are 2 methods to model (airbag) venting. The accumulated +mass output of both may be tracked via the *DATABASE_FSI card (“pleak” +parameter in the “dbfsi” ASCII output file). +a) Isentropic Venting. In isentropic venting, (define NVENT on card 3) the +flow crossing the vent hole surface is estimated from the isentropic equa- +tion. All airbag shell normal vectors should point uniformly in the same +direction: typically, inward. The shell elements for the vent holes, includ- +ed in the Lagrangian coupling set, should also point in the same direction +as the airbag meaning usually inward. For more details on isentropic +venting see *AIRBAG_WANG_NEFSKE mass flow rate equation for op- +tion OPT EQ.1 and 2. +b) Physical Venting. Physical venting models involve holes in the Lagran- +gian structure (usually airbags). The shell parts representing the vent +holes may be either excluded from the Lagrangian coupling set, or, if in- +cluded, have normal vectors reversed from the rest of the airbag. Typical- +ly, this means the holes having outward facing normal vectors, since the +rest of the airbag has inward pointing normal vectors. With either ap- +proach the holes produce no coupling force to stop fluid leakage. +When a particular AMMG is present on both sides of the same Lagrangi- +an shell surface, penalty coupling can break down. Therefore, It is rec- +ommended that *ALE_FSI_SWITCH_MMG_ID be used to switch the +AMMG ID of the vented gas so that the vented gas outside the bag does +not lead to leakage. +12. Initial Penetration Check. Typically, penetration check (IPENCHK) should +only be used if there is high coupling force applied at t=0. For example, consid- +er a Lagrangian container, filled with non-gaseous fluid (i.e. ALE liquid or +solid) via the *INITIAL_VOLUME_FRACTON_GEOMETRY command. Some- +times due to mesh resolution or complex container geometry, there is initial +penetration of the fluid across the container surface. This can give rise to a +sharp and immediate coupling force on the fluid at t=0. Turning on IPENCHK +may help eliminate this spike in coupling force. +13. Porous Flow for Shell Elements. For shell, CTYPE=11, the Ergun-type +empirical porous flow equation is applied to the normal flow direction across +the porous surface. The pressure gradient along the segment normal direction +is +𝑑𝑃 +𝑑𝑥𝑛 += 𝐴𝑛(𝜀, 𝜇)𝑉𝑛 + 𝐵𝑛(𝜀, 𝜌)|𝑉𝑛|𝑉𝑛 +where the subscript “n” refers to the direction normal to the porous Lagrangian +shell surface and where, +a) 𝑉𝑛 is the relative normal-to-porous-shell-surface fluid velocity compo- +nent. +b) 𝐴𝑛(𝜀, 𝜇) = 𝐴1(𝜀, 𝜇) is a viscous coefficient of the Ergun-type porous flow +equation. As applied here it should contain the fluid dynamic viscosity, + 𝜇 , and shell porosity, 𝜀 information. +c) 𝐵𝑛(𝜀, 𝜌) = 𝐵1(𝜀, 𝜌) is an inertial coefficient of the Ergun-type porous flow +equation. As applied here it should contain the fluid density, 𝜌, and shell +porosity, 𝜀, information. +The force increment applied per segment is +𝐹𝑛 = +𝑑𝜌 +𝑑𝑥𝑛 +× THKF × 𝑆, +N5 +N1 +N8 +Ez +N4 +Ey +Ex +N6 +N2 +N7 +N3 +Figure 10-33. The Ex direction is aligned along the line segment connecting +the centers of the 2-3-6-7 and the 1-4-8-5 faces. The Ey direction is orthogonal +to the Ex direction and in the plane containing both Ex and containing the +segment connecting the centers of the 1-2-6-5 and 3-4-8-7 faces. The Ez is +normal to this plane. +where, 𝑆 is the segment surface area. +If *DEFINE_POROUS_LAGRANGIAN defines the porous properties of a slave +element, the porous forces are computed with an equation similar to the one +used in *LOAD_BODY_POROUS +NOTE: 𝐴𝑖(𝜀, 𝜇), 𝐵𝑖(𝜀, 𝜌), and THKF are required input for porous +shell coupling. +14. Porous Flow for Solid Elements. For porous solid, CTYPE=12, the pressure +gradient along each global direction (i) can be computed similarly. +𝑑𝑃 +𝑑𝑥𝑖 += 𝐴𝑖(𝜀, 𝜇)𝑉𝑖 + 𝐵𝑖(𝜀, 𝜌)|𝑉𝑖|𝑉𝑖 for 𝑖 = 1,2,3 +Where, +a) 𝑉𝑖 is the relative fluid velocity component through the porous solid in the +3 global directions. +b) 𝐴𝑖(𝜀, 𝜇) is a viscous coefficient of the Ergun-type porous flow equation in +the ith direction. As applied here it should contain the fluid dynamic vis- +cosity, 𝜇, and shell porosity, 𝜀, information. +c) 𝐵𝑖(𝜀, 𝜌) is an inertial coefficient of the Ergun-type porous flow equation in +the ith direction. As applied here it should contain the fluid density (𝜌) +and solid porosity (𝜀) information. +NOTE: 𝐴𝑖(𝜀, 𝜇), and 𝐵𝑖(𝜀, 𝜌) are required input for porous solid +coupling. +system +If DIREC = 1, the pressure gradient in a solid is applied in a local reference +coordinate +If +*DEFINE_POROUS_LAGRANGIAN defines the porous properties of a slave +element, the local system can be adapted and the porous forces are computed +with an equation similar to the one used in *LOAD_BODY_POROUS. +defined +Figure +10-33. +in +*CONSTRAINED_LINEAR_GLOBAL +Purpose: Define linear constraint equations between displacements and rotations, +which can be defined in global coordinate systems. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCID +Type +I +Default +none +DOF Card. Define one card for each constrained degree-of-freedom. Input is +terminated when a "*" card is found. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NID +DOF +COEF +Type +I +Default +none +Remark +1 + VARIABLE +LCID +I +0 +I +0 +DESCRIPTION +Linear constraint definition ID. This ID can be used to identify a +set to which this constraint is a member. +NID +Node ID +VARIABLE +DESCRIPTION +DOF +Degree of freedom in the global coordinate system; +EQ.1: displacement along global 𝑥-direction +EQ.2: displacement along global 𝑦-direction +EQ.3: displacement along global 𝑧-direction +EQ.4: global rotation about global 𝑥-axis +EQ.5: global rotation about global 𝑦-axis +EQ.6: global rotation about global 𝑧-axis +COEF +Nonzero coefficient, 𝐶𝑘 +Remarks: +Nodes of a nodal constraint equation cannot be members of another constraint equation +or constraint set that constrain the same degrees-of-freedom, a tied interface, or a rigid +body; i.e. nodes cannot be subjected to multiple, independent, and possibly conflicting +constraints. Also care must be taken to ensure that single point constraints applied to +nodes in a constraint equation do not conflict with the constraint sets constrained +degrees-of-freedom. +In this section linear constraint equations of the form: +∑ 𝐶𝑘𝑢𝑘 = 𝐶0 +𝑘=1 +can be defined, where uk are the displacements and Ck are user defined coefficients. +Unless LS-DYNA is initialized by linking to an implicit code to satisfy this equation at +the beginning of the calculation, the constant C0 is assumed to be zero. The first +constrained degree-of-freedom is eliminated from the equations-of-motion: +its velocities and accelerations are given by +𝑢1 = 𝐶0 − ∑ +𝑘=2 +𝐶𝑘 +𝐶1 +𝑢𝑘 +𝑢̇1 = − ∑ +𝑘=2 +𝑢̈1 = − ∑ +𝑘=2 +𝐶𝑘 +𝐶1 +𝐶𝑘 +𝐶1 +𝑢̇𝑘 +𝑢̈𝑘, +respectively. In the implementation a transformation matrix, 𝐋, is constructed relating +the unconstrained, 𝐮, and constrained, 𝐮𝑐, degrees-of-freedom. The constrained +accelerations used in the above equation are given by: +𝐮̈𝑐 = [𝐋T𝐌𝐋]−1𝐋T𝐅 +where 𝐌 is the Diagonal lumped mass matrix and 𝐅 is the right hand side force vector. +This requires the inversion of the condensed mass matrix which is equal in size to the +number of constrained degrees-of-freedom minus one. +Example: +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *CONSTRAINED_LINEAR_GLOBAL +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Constrain nodes 40 and 42 to move identically in the z-direction. +$ +$ When the linear constraint equation is applied, it goes like this: +$ +$ 0 = C40uz40 + C42uz42 +$ +$ = uz40 - uz42 +$ +$ uz40 = uz42 +$ +$ where, +$ C40 = 1.00 coefficient for node 40 +$ C42 = -1.00 coefficient for node 42 +$ uz40 = displacement of node 40 in z-direction +$ uz42 = displacement of node 42 in z-direction +$ +$ +*CONSTRAINED_LINEAR +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ i +$ id + 2 +$ +$ nid dof coef + 40 3 1.00 + 42 3 -1.00 +$ +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +*CONSTRAINED_LINEAR_LOCAL +Purpose: Define linear constraint equations between displacements and rotations, +which can be defined in a local coordinate system. Each node may have a unique +coordinate ID. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCID +Type +I +Default +none +DOF Cards. Define one card for each constrained degree-of-freedom. Input is +terminated at next “*” card. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NID +DOF +CID +COEF +Type +I +Default +none +Remark +1 + VARIABLE +LCID +I +0 +I +0 +I +0 +DESCRIPTION +LCID for linear constraint definition. This ID can be used to +identify a set to which this constraint is a member. +NID +Node ID +VARIABLE +DESCRIPTION +DOF +Degree of freedom in the local coordinate system; +EQ.1: displacement along local x-direction +EQ.2: displacement along local y-direction +EQ.3: displacement along local z-direction +EQ.4: local rotation about local x-axis +EQ.5: local rotation about local y-axis +EQ.6: local rotation about local z-axis +CID +Local coordinate system ID number. If the number is zero, the +global coordinate system is used. +COEF +Nonzero coefficient, Ck +Remarks: +In this section linear constraint equations of the form: +∑ 𝐶𝑘 +𝑘=1 +𝐿 = 𝐶0 +𝑢𝑘 +𝐿 are the displacements in the local coordinate systems and Ck +can be defined, where 𝑢𝑘 +are user defined coefficients. Unless LS-DYNA is initialized by linking to an implicit +code to satisfy this equation at the beginning of the calculation, the constant C0 is +assumed to be zero. The first constrained degree-of-freedom is eliminated from the +equations-of-motion: +Its velocities and accelerations are given by +𝐿 = 𝐶0 − ∑ +𝑢1 +𝑘=2 +𝐶𝑘 +𝐶1 +𝐿 +𝑢𝑘 +𝐿 = − ∑ +𝑢̇1 +𝑘=2 +𝐿 = − ∑ +𝑢̈1 +𝑘=2 +𝐶𝑘 +𝐶1 +𝐶𝑘 +𝐶1 +𝑢̇𝑘 +𝑢̈𝑘 +respectively. The local displacements are calculated every time step using the local +coordinate systems defined by the user. More than one degree of freedom for a node +can be constrained by specifying a card for each degree of freedom. +WARNING: Nodes of a nodal constraint equation cannot be mem- +bers of another constraint equation or constraint set +that contains the same degrees-of-freedom, tied inter- +face, or rigid bodies. +Nodes must not be subject to multiple, independent, +and possibly conflicting constraints. Furthermore, +care must be taken to ensure that single point con- +straints applied to nodes in a constraint equation do +not conflict with the constraint set’s constrained de- +grees-of-freedom. +Purpose: Define a local boundary constraint plane. +*CONSTRAINED + Card 1 +Variable +Type +Default +1 +TC +1 +0 +2 +RC +1 +0 +3 +DIR +1 +0 +4 +X +F +0 +5 +Y +F +0 +8 +6 +Z +F +0 +7 +CID +1 +none + VARIABLE +DESCRIPTION +TC +Translational Constraint in local system: +EQ.1: constrained x translation, +EQ.2: constrained y translation, +EQ.3: constrained z translation, +EQ.4: constrained x and y translations, +EQ.5: constrained y and z translations, +EQ.6: constrained x and z translations, +EQ.7: constrained x, y, and translations. +RC +Rotational Constraint in local system: +EQ.1: constrained x-rotation, +EQ.2: constrained y-rotation, +EQ.3: constrained z-rotation, +EQ.4: constrained x and y rotations, +EQ.5: constrained y and z rotations, +EQ.6: constrained z and x rotations, +EQ.7: constrained x, y, and z rotations. +VARIABLE +DESCRIPTION +DIR +Direction of normal for local constraint plane. +EQ.1: local x, +EQ.2: local y, +EQ.3: local z. +Local x-coordinate of a point on the local constraint plane. +Local y-coordinate of a point on the local constraint plane. +Local z-coordinate of a point on the local constraint plane. +Coordinate system ID for orientation of the local coordinate +system. +X +Y +Z +CID +Remarks: +Nodes within a mesh-size-dependent tolerance are constrained on a local plane. This +option is recommended for use with r-method adaptive remeshing where nodal +constraints are lost during the remeshing phase. +*CONSTRAINED_MULTIPLE_GLOBAL +Purpose: Define global multi-point constraints for imposing periodic boundary +condition in displacement field. +2 +3 +4 +5 +6 +7 +8 + Card 1 +Variable +1 +ID +Type +I +Default +NOTE: For each constraint equation include a set of cards consisting of +(1) a Constraint Equation Definition Card and (2) NMP Coefficient +Cards. +Constraint Equation Definition Card. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NMP +Type +I +Default +Coefficient Cards. The next NMP cards adhere to this format. Each card sets a single +coefficient in the constraint equation. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NID +DIR +COEF +Type +I +I +F +Default +11 +8 +5 +7 +4 +*CONSTRAINED_MULTIPLE_GLOBAL +9 +6 +1 +3 + 3, 1, 1.0 + 1, 1,-1.0 +10 +10, 1,-1.0 +(3) − 𝑢1 +𝑢1 +(1) − 𝑢1 +(10) = 0 +1 +2 +3 +3 + 8, 1, 1.0 + 2, 1,-1.0 +11, 1,-1.0 +(8) − 𝑢1 +𝑢1 +(2) − 𝑢1 +(11) = 0 +*CONSTRAINED_MULTIPLE_GLOBAL +2 +3 + 3, 2, 1.0 + 1, 2,-1.0 +10, 2,-1.0 +(3) − 𝑢2 +𝑢2 +(1) − 𝑢2 +(10) = 0 +Figure 10-34. Simple example. + VARIABLE +DESCRIPTION +ID +Constraint set identification. All constraint sets should have a +unique set ID. +NMP +Number of nodes to be constrained mutually. +NID +DIR +Nodal ID +Direction in three-dimensional space to be constrained +EQ.1: 𝑥 direction +EQ.2: 𝑦 direction +EQ.3: 𝑧 direction +LT.0: Extra DOFs for user defined element formulation (e.g. - +1: the 1st extra DOF; -2: the 2nd extra DOF; …) +VARIABLE +DESCRIPTION +COEF +Coefficient 𝛼NID in constraint equation: +∑ 𝛼NID𝑢DIR +NID +(NID) = 0 +. +Remarks: +1. Defining multi-point constraints by this keyword can be demonstrated by the +following example: a two-dimensional unit square with four quadrilateral ele- +ments and 11 nodes as shown in the figure below, where the nodes #10 and #11 +are two dummy nodes serving as control points. +*CONSTRAINED_NODAL_RIGID_BODY_{OPTION}_{OPTION}_{OPTION} +Available options include: + +SPC +INERTIA +TITLE +If the center of mass is constrained use the SPC option. If the inertial properties are +defined rather than computed use the INERTIA option. A description for the nodal +rigid body can be defined with the TITLE option. +Purpose: Define a nodal rigid body. This is a rigid body which consists of the defined +nodes. If the INERTIA option is not used, then the inertia tensor is computed from the +nodal masses. Arbitrary motion of this rigid body is allowed. If the INERTIA option is +used, constant translational and rotational velocities can be defined in a global or local +coordinate system. +The first node in the nodal rigid body definition is treated as the master for the case +where DRFLAG and RRFLAG are nonzero. The first node always has six degrees-of- +freedom. The release conditions applied in the global system are sometimes convenient +in small displacement linear analysis, but, otherwise, are not recommended. It is +strongly recommended, especially for implicit calculations, that release conditions are +only used for a two noded nodal rigid body. +Card Format: +Card 1: +required +Card 2: +required for SPC option +Card 3 - 5: +required for INERTIA option +Card 6: +required if a local coordinate system is used to specify the inertia +tensor when the INERTIA option is set +Remarks: +1. Unlike the *CONSTRAINED_NODE_SET which permits only constraints on +translational motion, here the equations of rigid body dynamics are used to +update the motion of the nodes and therefore rotations of the nodal sets are +admissible. Mass properties are determined from the nodal masses and coor- +dinates. Inertial properties are defined if and only if the INERTIA option is +specified. +Title Card. Additional card for the TITLE keyword option. + Optional +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +TITLE +A80 + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID +CID +NSID +PNODE +IPRT +DRFLAG +RRFLAG +Type +I +I +I +Default +none +none +none +I +0 +I +0 +I +0 +I +0 +Center of Mass Constraint Card. Additional card for the SPC keyword option. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CMO +CON1 +CON2 +Type +Default +F +0 +F +0 +F +0 + VARIABLE +DESCRIPTION +PID +CID +Part ID of the nodal rigid body. +Optional coordinate system ID for the rigid body local system, see +*DEFINE_COORDINATE_OPTION. Output of the rigid body +data and the degree-of- freedom releases are done in this local +system. This local system rotates with the rigid body. +VARIABLE +NSID +PNODE +DESCRIPTION +Nodal set ID, see *SET_NODE_OPTION. This nodal set defines +the rigid body. If NSID = 0, then NSID = PID, i.e., the node set ID +and the part ID are assumed to be identical. +An optional node (a massless node is allowed) used for post +processing rigid body data. If the PNODE is not located at the +rigid body’s center of mass, then the initial coordinates of PNODE +will be reset to the center of mass. If CID is defined, the velocities +and accelerations of PNODE will be output in the local system to +the d3plot and d3thdt files unless PNODE is specified as a +negative number, in which case the global system is used. +IPRT +Print flag. For nodal rigid bodies the following values apply: +EQ.1: write data into rbdout +EQ.2: do not write data into rbdout +Printing is suppressed for two noded rigid bodies unless IPRT is +set to unity. This is to avoid excessively large rbdout files when +many, two-noded welds are used. +DRFLAG +Displacement release flag for all nodes except the first node in the +definition. +EQ.-7: release 𝑥, 𝑦, and 𝑧 displacement in global system +EQ.-6: release 𝑧 and 𝑥 displacement in global system +EQ.-5: release 𝑦 and 𝑧 displacement in global system +EQ.-4: release 𝑥 and 𝑦 displacement in global system +EQ.-3: release 𝑧 displacement in global system +EQ.-2: release 𝑦 displacement in global system +EQ.-1: release 𝑥 displacement in global system +EQ.0: off for rigid body behavior +EQ.1: release 𝑥 displacement in rigid body local system +EQ.2: release 𝑦 displacement in rigid body local system +EQ.3: release 𝑧 displacement in rigid body local system +EQ.4: release 𝑥 and 𝑦 displacement in rigid body local system +EQ.5: release 𝑦 and 𝑧 displacement in rigid body local system +EQ.6: release 𝑧 and 𝑥 displacement in rigid body local system +EQ.7: release 𝑥, 𝑦, and 𝑧 displacement in rigid body local +VARIABLE +DESCRIPTION +system +RRFLAG +Rotation release flag for all nodes except the first node in the +definition. +EQ.-7: release 𝑥, 𝑦, and 𝑧 rotations in global system +EQ.-6: release 𝑧 and 𝑥 rotations in global system +EQ.-5: release 𝑦 and 𝑧 rotations in global system +EQ.-4: release 𝑥 and 𝑦 rotations in global system +EQ.-3: release 𝑧 rotation in global system +EQ.-2: release 𝑦 rotation in global system +EQ.-1: release 𝑥 rotation in global system +EQ.0: off for rigid body behavior +EQ.1: release 𝑥 rotation in rigid body local system +EQ.2: release 𝑦 rotation in rigid body local system +EQ.3: release 𝑧 rotation in rigid body local system +EQ.4: release 𝑥 and 𝑦 rotations in rigid body local system +EQ.5: release 𝑦 and 𝑧 rotations in rigid body local system +EQ.6: release 𝑧 and 𝑥 rotations in rigid body local system +EQ.7: release 𝑥, 𝑦, and 𝑧 rotations in rigid body local system +CMO +Center of mass constraint option, CMO: +EQ.+1.0: constraints applied in global directions, +EQ.0.0: no constraints, +EQ.-1.0: constraints applied +constraint). +in +local directions +(SPC +CON1 +First constraint parameter: +If CMO=+1.0, then specify global translational constraint: +EQ.0: no constraints, +EQ.1: constrained 𝑥 displacement, +EQ.2: constrained 𝑦 displacement, +EQ.3: constrained 𝑧 displacement, +EQ.4: constrained 𝑥 and 𝑦 displacements, +VARIABLE +DESCRIPTION +EQ.5: constrained 𝑦 and 𝑧 displacements, +EQ.6: constrained 𝑧 and 𝑥 displacements, +EQ.7: constrained 𝑥, 𝑦, and 𝑧 displacements. +If CM0 = -1.0, then specify local coordinate system ID. See *DE- +FINE_COORDINATE_OPTION: This coordinate system is fixed +in time +CON2 +Second constraint parameter: +If CMO=+1.0, then specify global rotational constraint: +EQ.0: no constraints, +EQ.1: constrained 𝑥 rotation, +EQ.2: constrained 𝑦 rotation, +EQ.3: constrained 𝑧 rotation, +EQ.4: constrained 𝑥 and 𝑦 rotations, +EQ.5: constrained 𝑦 and 𝑧 rotations, +EQ.6: constrained 𝑧 and 𝑥 rotations, +EQ.7: constrained 𝑥, 𝑦, and 𝑧 rotations. +If CM0 = -1.0, then specify local (SPC) constraint: +EQ.000000: no constraint, +EQ.100000: constrained 𝑥 translation, +EQ.010000: constrained 𝑦 translation, +EQ.001000: constrained 𝑧 translation, +EQ.000100: constrained 𝑥 rotation, +EQ.000010 : constrained 𝑦 rotation, +EQ.000001: constrained 𝑧 rotation. +Any combination of local constraints can be achieved by adding +the number 1 into the corresponding column. +Inertia Card 1. Additional card for the INERTIA keyword option. + Card 3 +Variable +Type +Default +1 +XC +F +0 +2 +YC +F +0 +3 +ZC +F +0 +4 +TM +F +0 +5 +6 +7 +8 +IRCS +NODEID +I +0 +I +0 + VARIABLE +DESCRIPTION +XC +YC +ZC +TM +𝑥-coordinate of center of mass. If nodal point, NODEID, is +defined, XC, YC, and ZC are ignored and the coordinates of the +nodal point, NODEID, are taken as the center of mass. +𝑦-coordinate of center of mass +𝑧-coordinate of center of mass +Translational mass +IRCS +Flag for inertia tensor reference coordinate system: +EQ.0: global inertia tensor, +EQ.1: local inertia tensor is given in a system defined by the +orientation vectors as given below. +NODEID +Optional nodal point defining the CG of the rigid body. If this +node is not a member of the set NSID above, its motion will not +be updated to correspond with the nodal rigid body after the +calculation begins. PNODE and NODEID can be identical if and +only if PNODE physically lies at the mass center at time zero. +Inertia Card 2. Second Additional card for the INERTIA keyword option. + Card 4 +1 +Variable +IXX +Type +F +Default +none +2 +IXY +F +0 +3 +IXZ +F +0 +4 +IYY +F +none +5 +IYZ +F +0 +6 +IZZ +F +0 +7 +8 + VARIABLE +DESCRIPTION +IXX +IXY +IXZ +IYY +IYZ +IZZ +𝐼𝑥𝑥, 𝑥𝑥 component of inertia tensor +𝐼𝑥𝑦, 𝑥𝑦 component of inertia tensor +𝐼𝑥𝑧, 𝑥𝑧 component of inertia tensor +𝐼𝑦𝑦, 𝑦𝑦 component of inertia tensor +𝐼𝑦𝑧, 𝑦𝑧 component of inertia tensor +𝐼𝑧𝑧, 𝑧𝑧 component of inertia tensor +Inertia Card 3. Third additional card for the INERTIA keyword option. + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +VTX +VTY +VTZ +VRX +VRY +VRZ +Type +Default +F +0 +F +0 +F +0 +F +0 +F +0 +F +0 + VARIABLE +DESCRIPTION +VTX +VTY +𝑥-rigid body initial translational velocity in global coordinate +system. +𝑦-rigid body initial translational velocity in global coordinate +system. +VARIABLE +DESCRIPTION +VTZ +VRX +VRY +𝑧-rigid body initial translational velocity in global coordinate +system. +𝑥-rigid body initial rotational velocity in global coordinate +system. +𝑦-rigid body initial rotational velocity in global coordinate +system. +VRZ +𝑧-rigid body initial rotational velocity in global coordinate system. +Remarks: +The velocities defined above can be overwritten by the *INITIAL_VELOCITY card. +Local Inertia Tensor Card. Additional card required for IRCS = 1 . +Define two local vectors or a local coordinate system ID. + Card 6 +Variable +1 +XL +Type +F +2 +YL +F +3 +ZL +F +4 +5 +6 +7 +8 +XLIP +YLIP +ZLIP +CID2 +F +F +F +I +Default +none +none +none +none +none +none +none + VARIABLE +DESCRIPTION +XL +YL +ZL +XLIP +YLIP +ZLIP +CID2 +𝑥-coordinate of local 𝑥-axis. Origin lies at (0,0,0). +𝑦-coordinate of local 𝑥-axis +𝑧-coordinate of local 𝑥-axis +𝑥-coordinate of local in-plane vector +𝑦-coordinate of local in-plane vector +𝑧-coordinate of local in-plane vector +Local coordinate system ID, see *DEFINE_COORDINATE_.... +With this option leave fields 1-6 blank. +Remarks: +The local coordinate system is set up in the following way. After the local x-axis is +defined, the local 𝑧-axis is computed from the cross-product of the local 𝑥-axis vector +with the given in-plane vector. Finally, the local 𝑦-axis is determined from the cross- +product of the local 𝑧-axis with the local 𝑥-axis. The local coordinate system defined by +CID has the advantage that the local system can be defined by nodes in the rigid body +which makes repositioning of the rigid body in a preprocessor much easier since the +local system moves with the nodal points. +Example: +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *CONSTRAINED_NODAL_RIGID_BODY +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Define a rigid body consisting of the nodes in nodal set 61. +$ +$ This particular example was used to connect three separate deformable +$ parts. Physically, these parts were welded together. Modeling wise, +$ however, this joint is quit messy and is most conveniently modeled +$ by making a rigid body using several of the nodes in the area. Physically, +$ this joint was so strong that weld failure was never of concern. +$ +*CONSTRAINED_NODAL_RIGID_BODY +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ pid cid nsid + 45 61 +$ +$ nsid = 61 nodal set ID number, requires a *SET_NODE_option +$ cid not used in this example, output will be in global coordinates +$ +$ +*SET_NODE_LIST +$ sid + 61 +$ nid1 nid2 nid3 nid4 nid5 nid6 nid7 nid8 + 823 1057 1174 1931 2124 1961 2101 +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +*CONSTRAINED_NODE_INTERPOLATION +Purpose: Define constrained nodes for the use of *ELEMENT_INTERPOLATION_- +SHELL and *ELEMENT_INTERPOLATION_SOLID to model contact and to visualize +the results of generalized elements . +The displacements of these nodes are dependent of their corresponding master nodes. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NID +NUMMN +Type +I +I +Default +none +none +Weighting Factor Cards. For each of the NUMMN master nodes NID depends on set a MN and W entry. Each +Weighting Factor Card can accommodate four master nodes. Add as many Weighting +Factor Cards as needed. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MN1 +W1 +MN2 +W2 +MN3 +W3 +MN4 +W4 +Type +I +F +I +F +I +F +I +F +Default +none +none +none +none +none +none +none +none + Card 3 +1 +Variable +MN5 +2 +W5 +3 +4 +5 +6 +7 +8 +Etc. +Etc. +Etc. +Etc. +Etc. +Etc. +Type +I +F +I +F +I +F +I +F +Default +none +none +none +none +none +none +none +none +26 +25 +24 +15 +14 +16 +26 +25 +78 +16 +15 +Connectivity of +Generalized-Shell Element +Generalized-Shell Element +(*ELEMENT_GENERALIZED_SHELL) +Interpolation Node +(*CONSTRAINED_NODE_INTERPOLATION) +Interpolation Element +(*ELEMENT_INTERPOLATION_SHELL) +*CONSTRAINED_NODE_INTERPOLATION +$---+--NID----+NUMCN----+----3----+----4----+----5----+----6----+----7----+----8 +78 +$---+--CN1----+---W1----+--CN2----+---W2----+--CN3----+---W3----+--CN4----+---W4 +0.15 +0.32 +0.18 +0.35 +26 +25 +16 +15 +Figure 10-35. Example of a *CONSTRAINED_NODE_INTERPOLATION +card + VARIABLE +NID +DESCRIPTION +Node ID of the interpolation node as defined in *NODE . +NUMMN +Number of master nodes, this constrained node depends on. +Node ID of master node i. +Weighting factor of master node i. +MNi +Wi +Remarks: +1. The coordinates of an interpolation node have to be defined in *NODE. In there +the translational and rotational constraints TC = 7. and RC = 7. need to be set. +2. The displacements of the interpolation node, 𝒅IN, are interpolated based on the +displacements of the corresponding master nodes, 𝒅𝑖, and the appropriate +weighting factors 𝑤𝑖. The interpolation is computed as follows: +NUMMN +𝒅IN = ∑ 𝑤𝑖𝒅𝑖 +𝑖=1 +. +*CONSTRAINED_NODE_SET_{OPTION} +To define an ID for the constrained node set the following option is available: + +ID +If the ID is defined an additional card is required. +Purpose: Define nodal constraint sets for translational motion in global coordinates. +No rotational coupling. See Figure 10-36. Nodal points included in the sets should not +be subjected to any other constraints including prescribed motion, e.g., with the +*BOUNDARY_PRESCRIBED_MOTION options. +ID Card. Additional card for ID keyword option. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CNSID +Type +Default +I +0 + Card 2 +1 +2 +Variable +NSID +DOF +Type +I +I +3 +TF +F +Default +none +none +1.E+20 +Remarks +1 +2 +4 +5 +6 +7 +8 + VARIABLE +DESCRIPTION +CNSID +Optional constrained node set ID. +NSID +Nodal set ID, see *SET_NODE_OPTION. +Since no rotation is permitted, this +option should not be used to model +rigid body behavior +involving +rotations +*CONSTRAINED_NODE_SET +*CONSTRAINED_NODAL_RIGID_BODY +*CONSTRAINED_SPOTWELD +Behavior is like a rigid beam. These +options may be used to model spotwelds. +Figure 10-36. Two different ways to constrain node 𝑎 and 𝑏. For rigid-body +type situations this card, *CONSTRAINED_NODE_SET may lead to un- +physical results. + VARIABLE +DESCRIPTION +DOF +Applicable degrees-of-freedom: +EQ.1: x-translational degree-of-freedom, +EQ.2: y-translational degree-of-freedom, +EQ.3: z-translational degree-of-freedom, +EQ.4: x and y-translational degrees-of-freedom, +EQ.5: y and z-translational degrees-of-freedom, +EQ.6: z and x-translational degrees-of-freedom, +EQ.7: x, y, and z-translational degrees-of-freedom. +TF +Failure time for nodal constraint set. +Remarks: +1. The masses of the nodes are summed up to determine the total mass of the +constrained set. It must be noted that the definition of a nodal rigid body is not +possible with this input For nodal rigid bodies the keyword input: *CON- +STRAINED_NODAL_RIGID_BODY_OPTION, must be used. +2. When the failure time, TF, is reached the nodal constraint becomes inactive and +the constrained nodes may move freely. +Example: +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *CONSTRAINED_NODE_SET +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Constrain all the nodes in a nodal set to move equivalently +$ in the z-direction. +$ +*CONSTRAINED_NODE_SET +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 + nsid dof tf + 7 3 10.0 +$ +$ nsid = 7 nodal set ID number, requires a *SET_NODE_option +$ dof = 3 nodal motions are equivalent in z-translation +$ tf = 3 at time=10. the nodal constraint is removed +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +*CONSTRAINED_NODE_TO_NURBS_PATCH_{OPTION} +Purpose: To add additional massless nodes to the surface of a NURBS patch. The +motion of the nodes is governed by the NURBS patch. Forces applied to the nodes are +distributed to the NURBS patch. Penalty method is used to handle the displacement +boundary conditions CON on the specified nodes. +To specify node sets instead of individual nodes use the option: +SET +6 +7 +8 + Card 1 +1 +2 +3 +4 +Variable +PATCHID +NSID +CON +CID +Type +I +I +Default +none +none +I +I +0 +5 +SF +F +1.0 + VARIABLE +DESCRIPTION +PATCHID +Patch ID. +NSID +CON +CID +SF +Nodal set ID or node ID depending on the OPTION. +Constraint parameter for extra node(s) of NSID. Its definition is +in +same as that of CON2 when CM0 = -1 as described +MAT_RIGID. + For example “1110” means constrained 𝑧- +translation, 𝑥-rotation and 𝑦-rotation. +Coordinate system ID for constraint +Penalty force scale factor for the penalty-based constraint +*CONSTRAINED +Purpose: Constrain two points with the specified coordinates connecting two shell +elements at locations other than nodal points. In this option, the penalty method is +used to constrain the translational and rotational degrees-of-freedom of the points. +Force resultants are written into the swforc ASCII file for post-processing. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CID +Type +I +Default +none + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +Variable +EID1 +Type +I +Default +none +X1 +F +0. +Y1 +F +0. +Z1 +F +0. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +Variable +EID2 +Type +I +Default +none +X2 +F +0. +Y2 +F +0. +Z2 +F +0. +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PSF +FAILA +FAILS +FAILM +Type +F +F +F +F +Default +1.0 +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +CID +EIDi +Constrained points ID. +Shell element ID, i = 1, 2. +Xi, Yi, Zi +Coordinates of the constrained points, i = 1, 2. +PSF +Penalty scale factor (Default = 1.0). +FAILA +Axial force resultant failure value, no failure if zero. +FAILS +Shear force resultant failure value, no failure if zero. +FAILM +Moment resultant failure value, no failure if zero. +*CONSTRAINED_RIGID_BODIES +Purpose: Merge two rigid bodies. One rigid body, called slave rigid body, is merged to +the other one called a master rigid body. This command applies to parts comprised of +*MAT_RIGID +bodies +(*CONSTRAINED_NODAL_RIGID_BODY). +nodal +rigid +but +not +to + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PIDM +PIDS +IFLAG +Type +I +I +Default +none +none +I +0 + VARIABLE +DESCRIPTION +PIDM +PIDS +IFLAG +Master rigid body part ID, see *PART. +Slave rigid body part ID, see *PART. +This flag is meaningful if and only if the inertia properties of the +Part, PIDM, are defined in PART_INERTIA. +EQ.1: Update the center-of-gravity, the translational mass, and +the inertia matrix of PIDM to reflect its merging with the +slave rigid body (PIDS). +EQ.0: The merged PIDS will not affect the properties defined in +PART_INERTIA for PIDM since it is assumed the prop- +erties already account for merged parts. The inertia +properties of PIDS will be computed from its nodal +masses if the properties are not defined in a PART_IN- +ERTIA definition. +Remarks: +1. The slave rigid body is merged to the master rigid body. The inertial properties +computed by LS-DYNA are based on the combination of the master rigid body +plus all the rigid bodies which are slaved to it unless the inertial properties of +the master rigid body are defined via the *PART_INERTIA keyword in which +case those properties are used for the combination of the master and slave rigid +bodies. Note that a master rigid body may have many slaves. +2. +3. +Independent rigid bodies must not share common nodes since each rigid body +updates the motion of its nodes independently of the other rigid bodies. If +common nodes exist between rigid bodies the rigid bodies sharing the nodes +must be merged. +It is also possible to merge rigid bodies that are completely separated and share +no common nodal points or boundaries. All actions valid for the master rigid +body, e.g., constraints, given velocity, are now also valid for the newly-created +rigid body. +Example: +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *CONSTRAINED_RIGID_BODIES +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Rigidly connect parts 35, 70, 71, and 72 to part 12. +$ All parts must be defined as rigid. +$ +$ This example is used to make a single rigid body out of the five parts +$ that compose the back end of a vehicle. This was done to save cpu time +$ and was determined to be valid because the application was a frontal +$ impact with insignificant rear end deformations. (The cpu time saved +$ was from making the parts rigid, not from merging them - merging was +$ more of a convenience in this case for post processing, for checking +$ inertial properties, and for joining the parts.) +$ +*CONSTRAINED_RIGID_BODIES +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ pidm pids + 12 35 + 12 70 + 12 71 + 12 72 +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +*CONSTRAINED_RIGID_BODY_INSERT +Purpose: This keyword is for modeling die inserts. One rigid body, called slave rigid +body, is constrained to move with another rigid body, called the master rigid body, in +all directions except for one. + Card 1 +Variable +1 +ID +2 +3 +4 +5 +6 +7 +8 +PIDM +PIDS +COORDID +IDIR +Type +I +I +I +I +Default +none +none +none +none + Card 2 +1 +2 +3 +4 +Variable MFLAG +MCID +DEATHM +I +3 +5 +6 +7 +8 +F +0.0 +3 +4 +5 +6 +7 +8 +Type +Default +I +0 + Card 3 +1 +I +0 +2 +Variable +PARTB +DEATHB +Type +Default +I +0 +F +0.0 + VARIABLE +DESCRIPTION +ID +PIDM +PIDS +Insert ID +Master (die) rigid body part ID, see *PART. +Slave (die insert) rigid body part ID, see *PART. +VARIABLE +COORDID +DESCRIPTION +Coordinate ID. The 𝑥 direction is the direction the insert moves +independently of the die. +IDIR +The direction the insert moves independently of the die. If +unspecified, it defaults to the local z direction, IDIR = 3. +MFLAG +Motion flag. +EQ.0: Relative motion is unconstrained. +EQ.1: The displacement of the insert relative to the die is +imposed. +EQ.2: The velocity of the insert relative to the die is imposed. +EQ.3: The acceleration of the insert relative to the die is +imposed. +MCID +Curve defining the motion of the die insert relative to the die. +DEATHM +Death time of the imposed motion. If it is equal to 0.0, the motion +is imposed for the entire analysis. +PARTB +Part ID for a discrete beam connected between the insert and die. +DEATHB +Death time for the discrete beam specified by BPART. +Remarks: +1. This capability is supported by both the implicit and explicit time integrators; +however, the joint death time DEATHM feature works only for explicit integra- +tion with the penalty method. +2. The translational joint constraining the die and the die insert are automatically +generated. The joint reaction forces will appear in the jntforc output file. +3. The translational motor constraining the remaining translational degree of +freedom is also automatically generated, and its reaction forces also appear in +the jntforc output file. +4. The automatically generated beam has its data written to the d3plot file, and all +of the optional appropriate output files. +*CONSTRAINED_RIGID_BODY_STOPPERS +Purpose: Rigid body stoppers provide a convenient way of controlling the motion of +rigid tooling in metalforming applications. The motion of a “master” rigid body is +limited by load curves. This option will stop the motion based on a time dependent +constraint. The stopper overrides prescribed motion boundary conditions (except +relative displacement) operating in the same direction for both the master and slaved +rigid bodies. See Figure 10-37. + Card 1 +1 +2 +3 +4 +5 +6 +7 +Variable +PID +LCMAX +LCMIN +PSIDMX +PSIDMN +LCVMNX +DIR +8 +VID +I +0 +3 +I +0 +4 +I +0 +5 +I +I +I +0 +required +0 +6 +7 +8 +Type +I +I +Default +required +0 + Card 2 +Variable +Type +Default +1 +TB +F +0 +2 +TD +F +1021 + VARIABLE +DESCRIPTION +PID +Part ID of master rigid body, see *PART. +LCMAX +Load curve ID defining the maximum coordinate or displacement +as a function of time. See *DEFINE_CURVE: +LT.0: Load Curve ID |LCMAX| provides an upper bound for +the displacement of the rigid body +EQ.0: no limitation of the maximum displacement. +GT.0: Load Curve ID LCMAX provides an upper bound for the +position of the rigid body center of mass +Slave2 +C.G. +Slave 1 +C.G. +Master +C.G. +D1 +D2 +Rigid Body +Stopper +Figure 10-37. When the master rigid body reaches the rigid body stopper, the +velocity component into the stopper is set to zero. Slave rigid bodies 1 and 2 +also stop if the distance between their mass centers and the master rigid body +is less than or equal to the input values D1 and D2, respectively. + VARIABLE +LCMIN +PSIDMX +DESCRIPTION +Load curve ID defining the minimum coordinate or displacement +as a function of time. See *DEFINE_CURVE: +LT.0: Load Curve ID |LCMIN| defines a lower bound for the +displacement of the rigid body +EQ.0: no limitation of the minimum displacement. +GT.0: Load Curve ID LCMIN defines a lower bound for the +position of the rigid body center of mass +Optional part set ID of rigid bodies that are slaved in the +maximum coordinate direction to the master rigid body. The part +set definition, may be used to define +the closure distance (D1 and D2 in Figure 10-37) which activates +the constraint. The constraint does not begin to act until the +master rigid body stops. If the distance between the master rigid +body is greater than or equal to the closure distance, the slave +rigid body motion away from the master rigid body also stops. +However, the slaved rigid body is free to move towards the +VARIABLE +DESCRIPTION +PSIDMN +master. If the closure distance is input as zero (0.0) then the +slaved rigid body stops when the master stops. +Optional part set ID of rigid bodies that are slaved in the +minimum coordinate direction to the master rigid body. The part +set definition, may be used to define +the closure distance (D1 and D2 in Figure 10-37) which activates +the constraint. The constraint does not begin to act until the +master rigid body stops. If the distance between the master rigid +body is less than or equal to the closure distance, the slave rigid +body motion towards the master rigid body also stops. However, +the slaved rigid body is free to move away from the master. If the +closure distance is input as zero (0.0) then the slaved rigid body +stops when the master stops. +LCVMX +Load curve ID which defines the maximum absolute value of the +velocity as a function of time that is allowed for the master rigid +body. See *DEFINE_CURVE: +EQ.0: no limitation on the velocity. +DIR +Direction stopper acts in: +EQ.1: x-translation, +EQ.2: y-translation, +EQ.3: z-translation, +EQ.4: arbitrary, defined by vector VID , +EQ.5: x-axis rotation, +EQ.6: y-axis rotation, +EQ.7: z-axis rotation, +EQ.8: arbitrary, defined by vector VID . +Vector for arbitrary orientation of stopper, see *DEFINE_VEC- +TOR. +Time at which stopper is activated. +Time at which stopper is deactivated. +VID +TB +TD +Remarks: +The optional definition of part sets in minimum or maximum coordinate direction +allows the motion to be controlled in arbitrary direction. +*CONSTRAINED_RIVET_{OPTION} +To define an ID for the rivet, the following option is available: + +ID +If the ID is defined an additional card is required. +Purpose: Define massless rivets between non-contiguous nodal pairs. The nodes must +not have the same coordinates. The action is such that the distance between the two +nodes is kept constant throughout any motion. No failure can be specified. +ID Card. Additional card for the ID keyword option. +ID +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RID +Type +Default + Card 1 +Variable +I +0 +1 +N1 +Type +I +2 +N2 +I +3 +TF +F +4 +5 +6 +7 +8 +Default +none +none +1.E+20 +Remarks +1 +2 + VARIABLE +DESCRIPTION +RID +N1 +N2 +Optional rivet ID. +Node ID +Node ID +VARIABLE +DESCRIPTION +TF +Failure time for nodal constraint set. +Remarks: +1. Nodes connected by a rivet cannot be members of another constraint set that +constrain the same degrees-of-freedom, a tied interface, or a rigid body, i.e., +nodes cannot be subjected to multiple, independent, and possibly conflicting +constraints. Also care must be taken to ensure that single point constraints +applied to nodes in a constraint set do not conflict with the constraint sets con- +strained degrees-of-freedom. +2. When the failure time, TF, is reached the rivet becomes inactive and the +constrained nodes may move freely. +Example: +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *CONSTRAINED_RIVET +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Connect node 382 to node 88471 with a massless rivet. +$ +*CONSTRAINED_RIVET +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ n1 n2 tf + 382 88471 0.0 +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +*CONSTRAINED_SHELL_TO_SOLID +Purpose: Define a tie between a shell edge and solid elements. Nodal rigid bodies can +perform the same function and may also be used. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NID +NSID +Type +I +I +Default +none +none + VARIABLE +DESCRIPTION +Shell node ID +Solid nodal set ID, see *SET_NODE_OPTION. +NID +NSID +Remarks: +The shell-brick interface, an extension of the tied surface capability, ties regions of +hexahedron elements to regions of shell elements. A shell node may be tied to up to +Nodes are constrained +to stay on fiber vector. +n1 +n2 +n3 +n4 +n5 +s3 +Nodes s1 and n3 are +coincident. +Figure 10-38. The interface between shell elements and solids ties shell node +s1 to a line of nodes on the solid elements n1-n5. It is very important for the +nodes to be aligned. +nine brick nodes lying along the tangent vector to the nodal fiber. See Figure 10-38. +During the calculation, the brick nodes thus constrained, must lie along the fiber but +can move relative to each other in the fiber direction. The shell node stays on the fiber +at the same relative spacing between the first and last brick node. The brick nodes must +be input in the order in which they occur, in either the plus or minus direction, as one +moves along the shell node fiber. +This feature is intended to tie four node shells to eight node shells or solids; it is not +intended for tying eight node shells to eight node solids. +Example: +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *CONSTRAINED_SHELL_TO_SOLID +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Tie shell element, at node 329, to a solid element at node 203. +$ - nodes 329 and 203 are coincident +$ +$ Additionally, define a line of nodes on the solids elements, containing +$ node 203, that must remain in the same direction as the fiber of the shell +$ containing node 329. In other words: +$ +$ - Nodes 119, 161, 203, 245 and 287 are nodes on a solid part that +$ define a line on that solid part. +$ - This line of nodes will be constrained to remain linear throughout +$ the simulation. +$ - The direction of this line will be kept the same as the fiber of the +$ of the shell containing node 329. +$ +*CONSTRAINED_SHELL_TO_SOLID +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ nid nsid + 329 4 +$ +*SET_NODE_LIST +$ sid + 4 +$ nid1 nid2 nid3 nid4 nid5 nid6 nid7 nid8 + 119 161 203 245 287 +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +*CONSTRAINED +Purpose: Define an elastic cubic spline interpolation constraint. The displacements and +slopes at the end points are continuous. The first and last nodes, which define the +constraint, must be independent. The degrees-of-freedom of interior nodes may be +either dependent or independent. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SPLID +DLRATIO +Type +Default +I +0 +I +0.10 +Node Cards. Include one card per independent/dependent node. The first and last +nodes must be independent. The next “*” card terminates this input. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NID +DOF +Type +Default +I +0 +I +0 + VARIABLE +DESCRIPTION +SPLID +Spline constraint ID. +DLRATIO +NID +Ratio of bending to torsional stiffness for an elastic tubular beam +which connects the independent degrees-of-freedom. The default +value is set to 0.10. +Independent/dependent node ID. For explicit problems this +node should not be a member of a rigid body, or elsewhere +constrained in the input. +VARIABLE +DOF +DESCRIPTION +Degrees-of-freedom. The list of dependent degrees-of-freedom +consists of a number with up to six digits, with each digit +representing a degree of freedom. For example, the value 1356 +indicates that degrees of freedom 1, 3, 5, and 6 are controlled by +the constraint. The default is 123456. Digit: degree of freedom +ID's: +EQ.1: x +EQ.2: y +EQ.3: z +EQ.4: rotation about x axis +EQ.5: rotation about y axis +EQ.6: rotation about z axis +*CONSTRAINED_SPOTWELD_{OPTION}_{OPTION} +If it is desired to use a time filtered force calculation for the forced based failure +criterion then the following option is available: + +FILTERED_FORCE +and one additional card must be defined below. To define an ID for the spotweld the +following option is available: + +ID +If the ID is defined an additional card is required. The ordering of the options is +arbitrary. +Purpose: Define massless spot welds between non-contiguous nodal pairs. +The spot weld is a rigid beam that connects the nodal points of the nodal pairs; thus, +nodal rotations and displacements are coupled. The spot welds must be connected to +nodes having rotary inertias, i.e., beams or shells. If this is not the case, for example, if +the nodes belong to solid elements, use the option: *CONSTRAINED_RIVET. During +implicit calculations this case is treated like a rivet, constraining only the displacements. +Note that shell elements do not have rotary stiffness in the normal direction and, +therefore, this component cannot be transmitted. +Spot welded nodes must not have the same coordinates. Coincident nodes in a spot +weld can be handled by the *CONSTRAINED_NODAL_RIGID_BODY option. Brittle +and ductile failures are supported by this model. Brittle failure is based on the resultant +forces acting on the weld, and ductile failure is based on the average plastic strain value +of the shell elements which include the spot welded node. Spot welds, which are +connected to massless nodes, are automatically deleted in the initialization phase and a +warning message is printed in the messag file and the d3hsp file. +Warning. The accelerations of spot welded nodes are output as zero into the various +databases, but if the acceleration of spotwelded nodes are required, use either the +*CONSTRAINED_GENERALIZED_WELD or the *CONSTRAINED_NODAL_RIGID_- +BODY input. However, if the output interval is frequent enough accurate acceleration +time histories can be obtained from the velocity time history by differentiation in the +post-processing phase. +ID Card. Additional card for the ID keyword option. +ID +1 +2 +3 +4 +5 +6 +7 +8 +Variable +WID +Type +Default + Card 1 +Variable +I +0 +1 +N1 +Type +I +2 +N2 +I +3 +SN +F +4 +SS +F +5 +N +F +6 +M +F +7 +TF +F +8 +EP +F +Default +none +none optional optional +none +none +1.E+20 1.E+20 +Remarks +1. +2. +3 +4 +Filter Card. Additional card for the FILTERED_FORCE keyword option. +3 +4 +5 +6 +7 +8 + Card 2 +Variable +1 +NF +2 +TW +Type +I +F +Default +none +none + VARIABLE +DESCRIPTION +WID +Optional weld ID. +N1 +N2 +SN +Node ID +Node ID +Normal force at spotweld failure . +VARIABLE +DESCRIPTION +Shear force at spotweld failure . +Exponent for normal spotweld force . +Exponent for shear spotweld force . +Failure time for nodal constraint set. +Effective plastic strain at failure. +Number of force vectors stored for filtering. +Time window for filtering. +SS +N +M +TF +EP +NF +TW +Remarks: +1. Nodes connected by a spot weld cannot be members of another constraint set +that constrain the same degrees-of-freedom, a tied interface, or a rigid body, i.e., +nodes cannot be subjected to multiple, independent, and possibly conflicting +constraints. Also, care must be taken to ensure that single point constraints +applied to nodes in a constraint set do not conflict with the constraint sets con- +strained degrees-of-freedom. +2. Failure of the spot welds occurs when: +) +( +∣𝑓𝑛∣ +𝑆𝑛 ++ ( +∣𝑓𝑠∣ +��𝑠 +) +≥ 1 +where fn and fs are the normal and shear interface force. Component fn is non- +zero for tensile values only. +3. When the failure time, TF, is reached the spot weld becomes inactive and the +constrained nodes may move freely. +4. Spot weld failure due to plastic straining occurs when the effective nodal plastic +𝑝 . This option can model the tearing out of a +strain exceeds the input value,εfail +spotweld from the sheet metal since the plasticity is in the material that sur- +rounds the spotweld, not the spotweld itself. A least squares algorithm is used +to generate the nodal values of plastic strains at the nodes from the element +integration point values. The plastic strain is integrated through the element +and the average value is projected to the nodes via a least square fit. This op- +tion should only be used for the material models related to metallic plasticity +and can result is slightly increased run times. Failures can include both the +plastic and brittle failures. +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$$ +$ +$$$$ *CONSTRAINED_SPOTWELD +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$$ +$ +$ Spotweld two nodes (34574 and 34383) with the approximate strength +$ of a 3/8" SAE Grade No 3 bolt. +$ +*CONSTRAINED_SPOTWELD +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>... +.8 +$ n1 n2 sn sf n m tf +ps + 34574 34383 36.0 18.0 2.0 2.0 10. +1.0 +$ +$ +$ sn = 36.0 normal failure force is 36 kN +$ sf = 18.0 shear failure force is 18 kN +$ n = 2.0 normal failure criteria is raised to the power of 2 +$ m = 2.0 shear failure criteria is raised to the power of 2 +$ tf = 10.0 failure occurs at time 10 unless strain failure occurs +$ ps = 2.0 plastic strain at failure +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$$ +5. Thermal: The 2 nodes identified by this keyword will be constrained to the +same temperature in a thermal problem or in a couple thermal-mechanical +problem. +*CONSTRAINED +Purpose: Define a self-piercing rivet with failure. This model for a self-piercing rivet +(SPR2) includes a plastic-like damage model that reduces the force and moment +resultants to zero as the rivet fails. The domain of influence is specified by a diameter, +which should be approximately equal to the rivet’s diameter. +The location of the rivet is defined by a single node at the center of two riveted sheets. +The algorithm does a normal projection from the master and slave sheets to the rivet +node and locates all nodes within the user-defined diameter of influence. The +numerical implementation of this rivet model was developed by L. Olovsson of +Impetus Afea, based on research work on SPR point connector models originally carried +out by SIMLab (NTNU) and SINTEF, see references by Porcaro, Hanssen, and et.al. +[2006, 2006, 2007]. +Originally only two sheets (master and slave) could be connected with one SPR2 node. +But since release R9, up to 6 sheets can be connected with one SPR2 by defining +additional parts on optional card 4. The following stacking sequence should be used: +MID – XPID1 – XPID2 – XPID3 – XPID4 – SID. Omitted parts can be left blank, e.g. for +a 3-sheet connection the extra part lies in between master and slave, and for a regular 2- +sheet connection card 4 can be dropped completely. + Card 1 +1 +2 +3 +4 +Variable +MID +SID +NSID +THICK +Type +I +I +I +F +5 +D +F +6 +FN +F +7 +FT +F +8 +DN +F +Default +none +none +none +none +none +none +none +none + Card 2 +Variable +1 +DT +2 +XIN +3 +4 +5 +6 +7 +8 +XIT +ALPHA1 +ALPHA2 +ALPHA3 +DENS +INTP +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +0.0 +*CONSTRAINED_SPR2 + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EXPN +EXPT +Type +F +F +Default +8.0 +8.0 +Card 4 is optional. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +XPID1 +XPID2 +XPID3 +XPID4 +Type +I +I +I +I +Default +none +none +none +none + VARIABLE +DESCRIPTION +MID +SID +Master sheet Part ID +Slave sheet Part ID +NSID +Node set ID of rivet location nodes. +THICK +Total thickness of master and slave sheet. +D +FN +FT +DN +DT +XIN +XIT +Rivet diameter. +Rivet strength in tension (pull-out). +Rivet strength in pure shear. +Failure displacement in normal direction. +Failure displacement in tangential direction. +Fraction of failure displacement at maximum normal force. +Fraction of failure displacement at maximum tangential force. +VARIABLE +DESCRIPTION +ALPHA1 +Dimensionless parameter scaling the effective displacement. +ALPHA2 +Dimensionless parameter scaling the effective displacement. +ALPHA3 +Dimensionless parameter scaling the effective displacement. The +sign of ALPHA3 can be used to choose the normal update +procedure: +GT.0: incremental update (default), +LT.0: total update (recommended). +Rivet density (necessary for time step calculation). +Flag for interpolation. +EQ.0: linear (default), +EQ.1: uniform, +EQ.2: inverse distance weighting. +Exponent value for load function in normal direction. +Exponent value for load function in tangential direction. +Extra part id 1 for multi-sheet connection. +Extra part id 2 for multi-sheet connection. +Extra part id 3 for multi-sheet connection. +Extra part id 4 for multi-sheet connection. +DENS +INTP +EXPN +EXPT +XPID1 +XPID2 +XPID3 +XPID4 +Self-piercing rivets are a type of fastener that is sometimes used in place of spot welds +to join sheet metal of similar or dissimilar materials. The rivet penetrates the first sheet, +expands to interlock with the lower sheet without penetration. The strength and fatigue +characteristics of self-piercing rivets can meet or even exceed that of spot welds; +consequently, their practical applications are expanding. +In the local description of the underlying model, all considerations are done in the +plane-of-maximum opening defined by +The unit normal vectors of the slave and master sheets are 𝐧̂𝑠 and 𝐧̂𝑚 respectively , and tangential unit normal vector of the rivet is +𝐧̂𝑜 = 𝐧̂𝑠 × 𝐧̂𝑚. +𝐧̂𝑡 = 𝐧̂𝑜 × 𝐧̂𝑚. +A single-sheet rivet system is assumed, i.e. the rivet translation and rotation follow the +motion of the master sheet. The opening appears at the slave sheet. +The local deformation is defined by normal stretch vector δ𝑛, tangential stretch 𝛅𝑡 and +total stretch δ = δ𝑛 + δ𝑡 . At any given time the total stretch is +𝑠 so that the scalar measures of normal +computed from the position vectors: δ = 𝐱𝑠 +stretch and tangential stretch are 𝜹𝒏 = δ ⋅ 𝐧̂𝑛 and 𝜹𝒕 = δ ⋅ 𝐧̂𝑡. The normal and tangential +forces 𝑓𝑛 and 𝑓𝑡 are then determined by the material model, which will be explained +next. +𝑟 − 𝐱𝑠 +The moments on the rivet always satisfy, +𝑀𝑚 + 𝑀𝑠 = (ℎ1 + ℎ2)𝑓𝑡/2. +The motion, the forces and moments are then distributed to the nodes within the radius +of influence by a weighting function, which is, by default, linear . +Master Sheet (offset centerline) +Slave Sheet +Figure 10-39. Plane of maximim opening. +Master sheet centerline +Rivet +Slave sheet centerline +Figure 10-40. Single-sheet rivet system. +Master sheet +Slave sheet +Figure 10-41. Local kinematics. +Master sheet +Slave sheet +Figure 10-42. Local forces/moments. +The force-deformation relationship is defined by a non-linear damage model for +arbitrary mixed-mode loading conditions (combination of tension and shear). For pure +tensile and pure shear loading, the behavior is given by, +max𝛿𝑡 +max𝛿𝑛 +𝑓𝑡 +𝑓𝑛 +fail +fail +𝜂max𝛿𝑛 +𝜂max𝛿𝑡 +𝑓 ̂ +𝑛(𝜂max), +𝑓 ̂ +𝑡(𝜂max) +𝑓𝑛 = +𝑓𝑡 = +(1) +Respectively where, +𝑓 ̂ +𝑛(𝜂max) = +⎧ +{{{ +⎨ +{{{ +⎩ +1 − ( +𝜉𝑛 − 𝜂max +𝜉𝑛 +EXPN +) +1 − +𝜂max − 𝜉𝑛 +1 − 𝜉𝑛 + 𝑓 ̂ +𝑡(𝜂max) = +⎧ +{{{ +⎨ +{{{ +⎩ +1 − ( +𝜉𝑡 − 𝜂max +𝜉𝑡 +EXPT +) +1 − +𝜂max − 𝜉𝑡 +1 − 𝜉𝑡 +𝜂max ≤ 𝜉𝑛 +𝜂𝑚𝑎𝑥 > 𝜉𝑛 +𝜂max ≤ 𝜉𝑡 +𝜂𝑚𝑎𝑥 > 𝜉𝑡 +(2) +In pure tension and pure shear the damage measure, 𝜂max(𝑡), defined in (3), simplifies +to coincide with strain as indicated in figure 10-43. +Unloading +reloading path +Unloading +reloading path +Pure Tension +Pure Shear +Figure 10-43. Force response of self penetrating rivet. +fail can be determined directly +max, 𝛿𝑛 +Usually, the material parameters 𝑓𝑛 +from experiments, whereas material parameters 𝜉𝑛, and 𝜉𝑡 can be found by reverse +engineering. For mixed-mode behavior, an effective displacement measure, 𝜂(𝜃), is +given by +fail, and 𝛿𝑡 +max, 𝑓𝑡 +𝜂(𝜃, 𝜂max, 𝑡 ) = [𝜉 (𝜃) + +1 − 𝜉 (𝜃) +𝛼(𝜂max) +] +√ +√√ +⎷ +] +[ +𝛿𝑛(𝑡) +fail +𝛿𝑛 ++ [ +] +, +𝛿𝑡(𝑡) +fail +𝛿𝑡 +(3) +where, +𝜃 = arctan ( +𝛿𝑛 +𝛿𝑡 +) +𝜂max(𝑡) = max[𝜂(𝑡)]. +The parameter 𝜉 (𝜃) which ranges from 0 to 1 scales the effective displacement as a +function of the direction of the displacement vector in the 𝛿𝑛-𝛿𝑡-plane according to, +𝜉 (𝜃) = 1 − +27 +( +2𝜃 +) ++ +27 +( +2𝜃 +) +. +(4) +The directional scaling of the effective displacement is allowed to change as damage +develops, which is characterized by the shape coefficient 𝛼(𝜂max) defined as +𝛼(𝜂max) = +⎧𝜉𝑡 − 𝜂max +{ +{ +𝜉𝑡 +⎨ +1 − 𝜂max +{ +{ +1 − 𝜉𝑡 +⎩ +𝛼1 + +𝜂max +𝜉𝑡 +𝛼2 +𝛼2 + +𝜂max − 𝜉𝑡 +1 − 𝜉𝑡 +𝜂max < 𝜉𝑡 +, +𝛼3 𝜂max ≥ 𝜉𝑡 +(5) +where 𝛼1, 𝛼2, and 𝛼3 are material parameters. +Pull-out +Peeling +Isolines of +(Failure isoline) +u e l o a d i n +b li q +Shear loading +Early yielding +Figure 10-44. Isosurfaces of 𝜂(𝜃) +The directional dependency of the effective displacement is necessary for an accurate +force-displacement response in different loading directions. The coefficients 𝛼1, and 𝛼2 +decrease the forces in the peeling and oblique loading cases to the correct levels. Both +parameters are usually less than 1; whereas 𝛼3 is typically larger than 1 as its main +purpose is to moderate the failure displacement in oblique loading directions. Several +qualitative features captured by this model are illustrated in Figure 10-44. +For the moment distribution, the difference between master sheet (stronger side where +the rivet is entered) and slave sheet (weaker side) is accounted for by a gradual transfer +from the slave to the master side as damage grows: +𝑀𝑚 = +ℎ1 + ℎ2 +(1 + +𝜂max − 𝜉1 +1 − 𝜉1 +) 𝑓1, +𝑀𝑠 = +ℎ1 + ℎ2 +(1 − +𝜂max − 𝜉1 +1 − 𝜉 +) 𝑓1 +(6) +Eventually the connection to the slave sheet becomes a moment free hinge. +It is recommended to use the drilling rotation constraint method for the connected +components in explicit analysis, i.e. parameter DRCPSID of *CONTROL_SHELL +should refer to all shell parts involved in SPR2 connections. +*CONSTRAINED_TIE-BREAK +Purpose: Define a tied shell edge to shell edge interface that can release locally as a +function of plastic strain of the shells surrounding the interface nodes. A rather ductile +failure is achieved. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SNSID +MNSID +EPPF +Type +I +I +F +Default +none +none +0. +Remarks +1, 2 +3, 4 + VARIABLE +DESCRIPTION +SNSID +Slave node set ID, see *SET_NODE_OPTION. +MNSID +Master node set ID, see *SET_NODE_OPTION. +EPPF +Plastic strain at failure +Remarks: +1. Nodes in the master node set must be given in the order they appear as one +moves along the edge of the surface. +2. Tie-breaks may not cross. +3. Tie-breaks may be used to tie shell edges together with a failure criterion on the +joint. If the average volume-weighted effective plastic strain in the shell ele- +ments adjacent to a node exceeds the specified plastic strain at failure, the node +is released. The default plastic strain at failure is defined for the entire tie-break +but can be overridden in the slave node set to define a unique failure plastic +strain for each node. +4. Tie-breaks may be used to simulate the effect of failure along a predetermined +line, such as a seam or structural joint. When the failure criterion is reached in +the adjoining elements, nodes along the slideline will begin to separate. As this +effect propagates, the tie-breaks will appear to “unzip,” thus simulating failure +of the connection. +*CONSTRAINED_TIED_NODES_FAILURE +Purpose: Define a tied node set with failure based on plastic strain. The nodes must be +coincident. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NSID +EPPF +ETYPE +Type +I +F +Default +none +0. +I +0 +Remarks 1, 2, 3, 4 + VARIABLE +DESCRIPTION +NSID +EPPF +Nodal set ID, see *SET_NODE_OPTION. +Plastic strain, volumetric strain, or damage (MAT_224) at failure. +ETYPE +Element type for nodal group: +EQ.0: shell, +EQ.1: solid element +Remarks: +1. This feature applies to solid and shell elements using plasticity material models, +and to solid elements using the honeycomb material *MAT_HONEYCOMB +(EPPF = plastic volume strain). The failure variable is the volume strain for +materials 26, 126, and 201. The failure variable is the damage for material 224, +and the equivalent plastic strain is used for all other plasticity models. The +specified nodes are tied together until the average volume weighted value of +the failure variable exceeds the specified value. Entire regions of individual +shell elements may be tied together unlike the tie-breaking shell slidelines. The +tied nodes are coincident until failure. When the volume weighted average of +the failure value is reached for a group of constrained nodes, the nodes of the +elements that exceed the failure value are released to simulate the formation of +a crack. +2. To use this feature to simulate failure, each shell element in the failure region +should be generated with unique node numbers that are coincident in space +with those of adjacent elements. Rather than merging these coincident nodes, +the *CONSTRAINED_TIED_NODES_FAILURE option ties the nodal points +together. As plastic strain develops and exceeds the failure strain, cracks will +form and propagate through the mesh. +3. Entire regions of individual shell elements may be tied together, unlike the +*CONSTRAINED_TIE-BREAK option. This latter option is recommended +when the location of failure is known, e.g., as in the plastic covers which hide +airbags in automotive structures. +4. When using surfaces of shell elements defined using the *CONSTRAINED_- +TIED_NODES_FAILURE option in contact, it is best to defined each node in the +surface as a slave node with the NODE_TO_SURFACE contact options. If this +is not possible, the automatic contact algorithms beginning with *CONTACT_- +AUTOMATIC_... all of which include thickness offsets are recommended. +Example: +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *CONSTRAINED_TIED_NODES_FAILURE +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Tie shell elements together at the nodes specified in nodal set 101. The +$ constraint will be broken when the plastic strain at the nodes exceeds 0.085. +$ +$ In this example, four shell elements come together at a common point. +$ The four corners of the shells are tied together with failure as opposed +$ to the more common method of merging the nodes in the pre-processing stage. +$ +*CONSTRAINED_TIED_NODES_FAILURE +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ nsid eppf + 101 0.085 +$ +$ +*SET_NODE_LIST +$ sid + 101 +$ nid1 nid2 nid3 nid4 nid5 nid6 nid7 nid8 + 775 778 896 897 +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +The keyword *CONTACT provides a way of treating interaction between disjoint parts. +Different types of contact may be defined: +*CONTACT_OPTION1_{OPTION2}_{OPTION3}_{OPTION4}_{OPTION5} +*CONTACT_ADD_WEAR +*CONTACT_AUTO_MOVE +*CONTACT_COUPLING +*CONTACT_ENTITY +*CONTACT_GEBOD_OPTION +*CONTACT_GUIDED_CABLE +*CONTACT_INTERIOR +*CONTACT_RIGID_SURFACE +*CONTACT_1D +*CONTACT_2D_OPTION1_{OPTION2}_{OPTION3} +The first, *CONTACT_..., is the general 3D contact algorithms. The second, *CON- +TACT_COUPLING, provides a means of coupling to deformable surfaces to MADY- +MO. The third, *CONTACT_ENTITY, treats contact using mathematical functions to +describe the surface geometry for the master surface. The fourth, *CONTACT_GEBOD +is a specialized form of the contact entity for use with the rigid body dummies . The fifth, *CONTACT_INTERIOR, is under development +and is used with soft foams where element inversion is sometimes a problem. Contact +between layers of brick elements is treated to eliminate negative volumes. The sixth, +*CONTACT_RIGID_SURFACE is for modeling road surfaces for durability and NVH +calculations. The seventh, *CONTACT_1D, remains in LS-DYNA for historical reasons, +and is sometimes still used to model rebars which run along edges of brick elements. +The last, *CONTACT_2D, is the general 2D contact algorithm based on those used +previously in LS-DYNA2D. +*CONTACT_OPTION1_{OPTION2}_{OPTION3}_{OPTION4}_{OPTION5}_{OPTION6} +Purpose: Define a contact interface in a 3D model. For contact in 2D models, see +*CONTACT_2D_OPTION. +OPTIONS FOR *CONTACT KEYWORD +OPTION +REQUIRED +DESCRIPTION +OPTION1 +OPTION2 +OPTION3 +OPTION4 +OPTION5 +OPTION6 +Yes +Specifies contact type +No +No +No +No +No +Flag for thermal +Flag indicating ID cards follow +Offset options +Flag for MPP +Flag for orthotropic friction +Allowed values for OPTION1 +All contact types are available for explicit and implicit calculations. +AIRBAG_SINGLE_SURFACE +AUTOMATIC_BEAMS_TO_SURFACE +AUTOMATIC_GENERAL +AUTOMATIC_GENERAL_EDGEONLY +AUTOMATIC_GENERAL_INTERIOR +AUTOMATIC_NODES_TO_SURFACE +AUTOMATIC_NODES_TO_SURFACE_SMOOTH +AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE +AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE_TIEBREAK +AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE_SMOOTH +AUTOMATIC_SINGLE_SURFACE +AUTOMATIC_SINGLE_SURFACE_MORTAR +AUTOMATIC_SINGLE_SURFACE_SMOOTH +AUTOMATIC_SINGLE_SURFACE_TIED +AUTOMATIC_SURFACE_TO_SURFACE +AUTOMATIC_SURFACE_TO_SURFACE_MORTAR +AUTOMATIC_SURFACE_TO_SURFACE_MORTAR_TIED +AUTOMATIC_SURFACE_TO_SURFACE_TIED_WELD +AUTOMATIC_SURFACE_TO_SURFACE_TIEBREAK +AUTOMATIC_SURFACE_TO_SURFACE_TIEBREAK_MORTAR +AUTOMATIC_SURFACE_TO_SURFACE_SMOOTH +CONSTRAINT_NODES_TO_SURFACE +CONSTRAINT_SURFACE_TO_SURFACE +DRAWBEAD +ERODING_NODES_TO_SURFACE +ERODING_SINGLE_SURFACE +ERODING_SURFACE_TO_SURFACE +FORCE_TRANSDUCER_CONSTRAINT +FORCE_TRANSDUCER_PENALTY +FORMING_NODES_TO_SURFACE +FORMING_NODES_TO_SURFACE_SMOOTH +FORMING_ONE_WAY_SURFACE_TO_SURFACE +FORMING_SURFACE_TO_SURFACE_MORTAR +FORMING_ONE_WAY_SURFACE_TO_SURFACE_SMOOTH +FORMING_SURFACE_TO_SURFACE +FORMING_SURFACE_TO_SURFACE_SMOOTH +NODES_TO_SURFACE +NODES_TO_SURFACE_INTERFERENCE +NODES_TO_SURFACE_SMOOTH +ONE_WAY_SURFACE_TO_SURFACE +ONE_WAY_SURFACE_TO_SURFACE_INTERFERENCE +ONE_WAY_SURFACE_TO_SURFACE_SMOOTH +RIGID_NODES_TO_RIGID_BODY +RIGID_BODY_ONE_WAY_TO_RIGID_BODY +RIGID_BODY_TWO_WAY_TO_RIGID_BODY +SINGLE_EDGE +SINGLE_SURFACE +SLIDING_ONLY +SLIDING_ONLY_PENALTY +SPOTWELD +SPOTWELD_WITH_TORSION +SPOTWELD_WITH_TORSION_PENALTY +SURFACE_TO_SURFACE +SURFACE_TO_SURFACE_INTERFERENCE +SURFACE_TO_SURFACE_SMOOTH +SURFACE_TO_SURFACE_CONTRACTION_JOINT +TIEBREAK_NODES_TO_SURFACE +TIEBREAK_NODES_ONLY +TIEBREAK_SURFACE_TO_SURFACE +TIED_NODES_TO_SURFACE +TIED_SHELL_EDGE_TO_SURFACE +TIED_SHELL_EDGE_TO_SOLID +TIED_SURFACE_TO_SURFACE +TIED_SURFACE_TO_SURFACE_FAILURE +Allowed values for OPTION2: +THERMAL +THERMAL_FRICTION +NOTE: THERMAL and THERMAL_FRICTION options are +restricted to contact types having “SURFACE_TO_- +SURFACE” in OPTION1. +Allowed value for OPTION3: +ID +Allowed values for OPTION4: +OPTION4 specifies that offsets may be used with the tied contact types. If one of these +three offset options is set, then offsets are permitted for these contact types, and, if not, +the nodes are projected back to the contact surface during the initialization phase and a +constraint formulation is used. Note that in a constraint formulation, the nodes of rigid +bodies are not permitted in the definition. +OFFSET +The OFFSET option switches the formulation from a constraint type formulation +to one that is penalty based where the force and moment (if applicable) result- +ants are transferred by discrete spring elements between the slave nodes and +master segments. +OFFSET is available when OPTION1 is: +TIED_NODES_TO_SURFACE +TIED_SHELL_EDGE_TO_SURFACE +TIED_SURFACE_TO_SURFACE +With this option, there is no coupling between the transmitted forces and mo- +ments and thus equilibrium is not enforced. In the TIED_SHELL_EDGE_TO_- +SURFACE contact, the BEAM_OFFSET option may be preferred since +corresponding moments accompany transmitted forces. Rigid bodies can be +used with this option. +BEAM_OFFSET +The BEAM_OFFSET option switches the formulation from a constraint type +formulation to one that is penalty based. Beam-like springs are used to transfer +force and moment resultants between the slave nodes and the master segments. +Rigid bodies can be used with this option. +BEAM_OFFSET is available when OPTION1 is: +TIED_SHELL_EDGE_TO_SURFACE +SPOTWELD +CONSTRAINED_OFFSET +The CONSTRAINED_OFFSET option is a constraint type formulation. +CONSTRAINED_OFFSET is available when OPTION1 is: +TIED_NODES_TO_SURFACE +TIED_SHELL_EDGE_TO_SURFACE +TIED_SURFACE_TO_SURFACE +SPOTWELD +Allowed value OPTION5: +MPP +Allowed value for OPTION6: +ORTHO_FRICTION +Remarks +1. Smooth Contact. For SMOOTH contact, a smooth curve-fitted surface is used +to represent the master segment, so that it can provide a more accurate repre- +sentation of the actual surface, reduce the contact noise, and produce smoother +results with coarser meshes. All contact options that include SMOOTH are +available for MPP. Only the FORMING contacts, wherein the master side is +rigid, can be used with SMOOTH in the case of SMP. +For SURFACE_TO_SURFACE and SINGLE_SURFACE contacts with SMOOTH +in MPP, both the slave and master sides are smoothed every cycle, thereby +slowing the contact treatment considerably. +The SMOOTH option does not apply to segment based (SOFT = 2) contacts. +2. Automatic General Contact. *CONTACT_AUTOMATIC_GENERAL is a +single surface contact similar to *CONTACT_AUTOMATIC_SINGLE_SUR- +FACE but which includes treatment of beam-to-beam contact and in doing so, +checks along the entire length of the beams for penetration. *CONTACT_AU- +TOMATIC_GENERAL essentially adds null beams to the exterior edges of shell +parts so that edge-to-edge treatment of the shell parts is handled by virtue of +contact of the automatically-generated null beams. By adding the word INTE- +RIOR to *CONTACT_AUTOMATIC_GENERAL, the contact algorithm goes a +step further by adding null beams to all the shell meshlines, both along the +exterior, unshared edges and the interior, shared shell edges. The EDGEONLY +option skips the node-to-surface contact and does only the edge-to-edge and +beam-to-beam contact. +3. Recommendations for TIED Contact Types. For tying solids-to-solids, that +is, for situations where none of the nodes have rotational degrees-of-freedom, +use TIED_NODES_TO_SURFACE and TIED_SURFACE_TO_SURFACE type +contacts. These contact types may include the OFFSET or CONSTRAINED_- +OFFSET option. +For tying shells-to-shells, beams-to-shells, that is, for situations where all the +nodes have rotational degrees-of-freedom, use TIED_SHELL_EDGE_TO_SUR- +FACE type contacts. This contact type may include the OFFSET, CON- +STRAINED_OFFSET, or BEAM_OFFSET option. +TIED_SHELL_EDGE_TO_SOLID is intended for tying shell edges to solids or +beam ends to solids, that is, situations where only the slave side nodes have +rotational degrees-of-freedom. +4. Tied Contact Types and the Implicit Solver. Non-physical results have been +observed when the implicit time integrator is used for models that combine tied +contact formulations with automatic single point constraints on solid element +rotational degrees of +(AUTOSPC on *CONTROL_IMPLICIT_- +SOLVER). The following subset of tied interfaces support a strongly objective +mode and verified to behave correctly with the implicit +time integrator: +freedom +1) TIED_NODES_TO_SURFACE_CONSTRAINED_OFFSET +2) TIED_NODES_TO_SURFACE_OFFSET +3) TIED_SHELL_EDGE_TO_SURFACE_CONSTRAINED_OFFSET +4) TIED_SHELL_EDGE_TO_SURFACE_BEAM_OFFSET +The first two of these ignore rotational degrees of freedom, while the third and +fourth constrain rotations. The first and third are constraint based; while the +second and fourth are penalty based. These four contact types are intended to +cover most use scenarios. +Setting IACC = 1 on *CONTROL_ACCURACY activates the strongly objective +formulation for the above mentioned contacts (as well as the non-offset options +*CONTACT_TIED_NODES_TO_SURFACE and *CONTACT_TIED_SHELL_- +EDGE_TO_SURFACE as a side effect). When active, forces and moments trans- +form correctly under superposed rigid body motions within a single implicit +step. Additionally, this formulation applies rotational constraints consistently +when, and only when, necessary. In particular, strong objectivity is implemented +so that slave nodes without rotational degrees of freedom are not rotationally +constrained, while slave nodes with bending and torsional rotations are rota- +tionally constrained. Additionally, strong objectivity ensures that the constraint +is physically correct. +For a master node belonging to a shell, the slave node’s bending rotations (rota- +tions in the plane of the master segment) are constrained to match the master +segment’s rotational degrees of freedom; for master nodes not belonging to a +shell, the slave’s bending rotations are constrained to the master segment rota- +tion as determined from its individual nodal translations. The slave node’s +torsional rotations (rotations with respect to the normal of the master segment) +are always constrained based on the master segment’s torsional rotation as de- +termined from its individual nodal translations, thus avoiding the relatively +weak drilling mode of shells. This tied contact formulation properly treats +bending and torsional rotations. Since slave node rotational degrees of freedom +typically come from shell or beam elements the most frequently used options +are: +TIED_SHELL_EDGE_TO_SURFACE_CONSTRAINED_OFFSET +TIED_SHELL_EDGE_TO_SURFACE_BEAM_OFFSET +The other two “non-rotational” formulations: +TIED_NODES_TO_SURFACE_CONSTRAINED_OFFSET +TIED_NODES_TO_SURFACE_OFFSET +are included for situations in which rotations do not need to be constrained at +all. See the LS-DYNA Theory Manual for further details. +5. Additional Remarks. Additional notes on contact types and a few examples +are provided at the end of this section in “General Remarks: *CONTACT”. A +theoretical discussion is provided in the LS-DYNA Theory Manual. +ADDITIONAL CARDS FOR *CONTACT KEYWORD +Cards must appear in the exact order listed below. +CARD +ID +MPP +Card 1 +Card 2 +Card 3 +Card 4 +DESCRIPTION +Card required when OPTION3 set to ID option; otherwise +this card is omitted. +Card required when OPTION5 set to MPP. +Always required. +Always required. +Always required. +Required for the following permutations of *CONTACT. +NOTE: The format of Card 4 is different for +each option listed below. +*CONTACT_AUTOMATIC_SINGLE_SURFACE_TIED +*CONTACT_CONSTRAINT_type +*CONTACT_DRAWBEAD +*CONTACT_ERODING_type +*CONTACT_…_INTERFERENCE +*CONTACT_RIGID_type +*CONTACT_TIEBREAK_type +*CONTACT_…_CONTRACTION_JOINT_type +THERMAL +Required if OPTION2 is set. Otherwise omit. +THERMAL_FRICTION Required if OPTION2 is set to THERMAL_FRICTION. +Otherwise omit. +ORTHO_FRICTION +Required if OPTION6 is set. Otherwise omit. Contains +friction coefficients +CARD +DESCRIPTION +Optional Card A +Optional parameters. +NOTE: Default values are highly optimized. +NOTE: Required if Optional Card B is includ- +ed. If Optional Card A is a blank line, +then values are set to their defaults, +and Optional Card B may follow. +Optional Card B +Optional parameters. Required if Optional Card C is +included. +Optional Card C +Optional parameters. Required if Optional Card D is +included. +Optional Card D +Optional parameters. Required if Optional Card E is +included. +Optional Card E +Optional parameters. +*CONTACT_OPTION1_{OPTION2}_… +Additional keyword for ID keyword option. +ID +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CID +Type +I +HEADING +A70 +The contact ID is needed during full deck restarts for contact initialization. If the +contact ID is undefined, the default ID is determined by the sequence of the contact +definitions, i.e., the first contact definition has an ID of 1, the second, 2, and so forth. In +a full deck restart without contact IDs, for a successful run no contact interfaces can be +deleted and those which are added must be placed after the last definition in the +previous run. The ID and heading is picked up by some of the peripheral LS-DYNA +codes to aid in post-processing. + VARIABLE +DESCRIPTION +CID +Contact interface ID. This must be a unique number. +HEADING +Interface descriptor. It is suggested that unique descriptions be +used. +MPP Cards. Variables set with these cards are only active when using MPP LS- +DYNA. +MPP Card 1. Additional card for the MPP option. This card is ignored, but still read +in, when SOFT = 2 on optional card A. + MPP 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IGNORE +BCKT +LCBCKT NS2TRK +INITITR +PARMAX +CPARM8 +Type +I +I +I +Default +0 +200 +none +I +3 +I +2 +F +See +below +I +0 +MPP Card 2. The keyword reader will interpret the card following MPP Card 1 as +MPP Card 2 if the first column of the card is occupied by an ampersand. Otherwise, it +is interpreted as Card 1. This card is ignored, but still read in, when SOFT = 2 on +optional card A. + MPP 2 +Variable +1 +& +2 +3 +4 +5 +6 +7 +8 +CHKSEGS +PENSF +GRPABLE +Type +Default +I +0 +F +1.0 +I +IGNORE +BCKT +LCBCKT +NS2TRK +INITITR +PARMAX +*CONTACT_OPTION1_{OPTION2}_… +DESCRIPTION +This is the same as the “ignore initial penetrations” option on the +*CONTROL_CONTACT Optional Card C entry 2 and can also be +specified in the normal contact control cards. It predates both of +those, and is not really needed anymore since both are honored +by the MPP code. That is, if any of the three are on, initial +penetrations are tracked. +Bucket sort frequency, this parameter does not apply when +SOFT = 2 on optional card A or to the Mortar contact (option +MORTAR on the CONTACT card). For the two exceptions, the +BSORT option on Optional Card A applies instead. +Load curve for bucket sort frequency, this parameter does not +apply when SOFT = 2 on optional card A or to the Mortar contact +(option MORTAR on the CONTACT card). + For the two +exceptions, the negative BSORT option on Optional Card A applies +instead. +Number of potential contacts to track for each slave node. The +normal input for this (DEPTH on Optional Card A) is ignored. +Number of iterations to perform when trying to eliminate initial +penetrations. Note: an input of 0 means 0, not the default value +(which is 2). Leaving this field blank will set INITITR to 2. +The parametric extension distance for contact segments. The +MAXPAR parameter on Optional Card A is not used for MPP. +For non-TIED contacts, the default is 1.0005. +For TIED contacts the default is 1.035 and, the actual extension +used is computed as follows: +PARMAXcomputed= +⎧1.0 + PARMAX +{{ +⎨ +{{ +⎩ +PARMAX +max(PARMAX, 1.035) +0.0 < PARMAX < 0.5 +1.0 ≤ PARMAX ≤ 1.0004 +otherwise +VARIABLE +CPARM8 +CHKSEGS +PENSF +DESCRIPTION +Flag for CONTACT_AUTOMATIC_GENERAL behavior. CPAR- +M8’s value is interpreted as two separate flags: OPT1 and OPT2 +according to the rule, +CPARM8 = OPT1 + OPT2. +When OPT1 and OPT2 are both set, both options are active. +OPT1: Flag to exclude beam-to-beam contact from the same PID. +EQ.0: Flag is not set (default). +EQ.1: Flag is set. +EQ.2: Flag is set. CPARM8 = 2 has the additional effect of +permitting contact treatment of spot weld (type 9) +beams +in AUTOMATIC_GENERAL contacts; spot +weld beams are otherwise disregarded entirely by AU- +TOMATIC_GENERAL contacts. +OPT2: Flag to shift generated beam affecting only shell-edge-to- +shell-edge treatment. See also SRNDE in Optional Card E. +EQ.10: Beam generated on exterior shell edge will be shifted +into the shell by half the shell thickness. Therefore, the +shell-edge-to-shell-edge contact starts right at the shell +edge and not at an extension of the shell edge. +If this value is non-zero, then the node to surface and surface to +surface contacts will perform a special check at time 0 for +elements that are inverted (or nearly so), and remove them from +contact. These poorly formed elements have been known to +occur on the tooling in metalforming problems, which allows +these problems to run. It should not normally be needed for +reasonable meshes. +This option is used together with IGNORE for 3D forging +problems. If non-zero, the IGNORED penetration distance is +multiplied by this value each cycle, effectively pushing the slave +node back out to the surface. This is useful for nodes that might +get generated below the master surface during 3D remeshing. +Care should be exercised, as energy may be generated and +stability may be effected for values lower than 0.95. A value in +the range of 0.98 to 0.99 or higher (but < 1.0) is recommended. +GRPABLE +*CONTACT_OPTION1_{OPTION2}_… +DESCRIPTION +Set to 1 to invoke an alternate MPP communication algorithm for +SINGLE_SURFACE, NODE_TO_SURFACE, and SURFACE_TO_- +SURFACE contacts. The new algorithm does not support all +contact options, including SOFT = 2, as of yet, and is still under +development. It can be significantly faster and scale better than +the normal algorithm when there are more than two or three +applicable contact types defined in the model. Its intent is to +speed up the contact processing but not to change the behavior of +*CONTROL_MPP_CONTACT_- +contact. +the +GROUPABLE. +also +See +Remarks: +1. The MPP cards are ignored by the segment based contact options that are made +active by setting SOFT = 2 on optional card A. When SOFT = 2. The BSORT +parameter on optional card A can be used to override the default bucket sort +frequency. +Card 1. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SSID +MSID +SSTYP +MSTYP +SBOXID MBOXID +SPR +MPR +Type +I +I +I +I +I +I +Default +none +none +none +none +I +0 +I +0 +Remarks +1 +2 +optional optional 0 = off +0 = off + VARIABLE +SSID +DESCRIPTION +Slave segment, node set ID, part set ID, part ID, or shell element +set ID, see *SET_SEGMENT, *SET_NODE_OPTION, *PART, +*SET_PART or *SET_SHELL_OPTION. For ERODING_SINGLE_- +SURFACE and ERODING_SURFACE_TO_SURFACE contact +types, use either a part ID or a part set ID. For ERODING_- +NODES_TO_SURFACE contact, use a node set which includes all +nodes that may be exposed to contact as element erosion occurs. +EQ.0: all part IDs are included for single surface contact, +automatic single surface, and eroding single surface. +MSID +Master segment set ID, part set ID, part ID, or shell element set +ID, see *SET_SEGMENT, *SET_NODE_OPTION, *PART, *SET_- +PART, or *SET_SHELL_OPTION: +EQ.0: for single surface contact, automatic single surface, and +eroding single surface. +VARIABLE +DESCRIPTION +SSTYP +ID type of SSID: +EQ.0: segment set ID for surface-to-surface contact, +EQ.1: shell element set ID for surface-to-surface contact, +EQ.2: part set ID, +EQ.3: part ID, +EQ.4: node set ID for node to surface contact, +EQ.5: include all (SSID is ignored), +EQ.6: part set ID for exempted parts. All non-exempted parts +are included in the contact. +For *AUTOMATIC_BEAMS_TO_SURFACE contact either a part +set ID or a part ID can be specified. +MSTYP +ID type of MSID: +EQ.0: segment set ID, +EQ.1: shell element set ID, +EQ.2: part set ID, +EQ.3: part ID. +SBOXID +MBOXID +EQ.4: node set ID (for eroding force transducer only. See +remark 3), +EQ.5: include all (MSID is ignored). +Include in contact definition only those slave nodes/segments +within box SBOXID (corresponding to BOXID in *DEFINE_BOX), +or if SBOXID is negative, only those slave nodes/segments +within contact volume |SBOXID| (corresponding to CVID in +*DEFINE_CONTACT_VOLUME). SBOXID can be used only if +SSTYP is set to 2 or 3, i.e., SSID is a part ID or part set ID. SBOX- +ID is not available for_ERODING contact options. +Include in contact definition only those master segments within +box MBOXID (corresponding to BOXID in *DEFINE_BOX), or if +MBOXID is negative, only those master segments within contact +volume |MBOXID| (corresponding to CVID in *DEFINE_CON- +TACT_VOLUME). MBOXID can be used only if MSTYP is set to +2 or 3, i.e., MSID is a part ID or part set ID. MBOXID is not +available for_ERODING contact options +DESCRIPTION +Include the slave side in the *DATABASE_NCFORC and the +*DATABASE_BINARY_INTFOR +files, and +optionally in the dynain file for wear: +interface +force +EQ.1: slave side forces included. +EQ.2: same as EQ.1, but also allows for slave nodes to be +written as *INITIAL_CONTACT_WEAR to dynain, see +NCYC on *INTERFACE_SPRINGBACK_LSDYNA. +Include the master side in the *DATABASE_NCFORC and the +*DATABASE_BINARY_INTFOR +files, and +optionally in the dynain file for wear: +interface +force +EQ.1: master side forces included. +EQ.2: same as EQ.1, but also allows for master nodes to be +written as *INITIAL_CONTACT_WEAR to dynain, see +NCYC on *INTERFACE_SPRINGBACK_LSDYNA. + VARIABLE +SPR +MPR +Remarks: +1. Giving a slave set ID equal to zero is valid only for the single surface contact +algorithms, i.e., the options: +SINGLE_SURFACE +AUTOMATIC_… +AIRBAG_… +ERODING_SINGLE_SURFACE +2. A master set ID is not defined for the single surface contact algorithms +(including AUTOMATIC_GENERAL). A master set ID is optional for FORCE_- +TRANSDUCERS. If a master set is defined for the FORCE_TRANSDUCER +option, only those force that develop between and master and slave surfaces are +considered. If a transducer is used for extracting forces from Mortar contacts, +the slave and master sides must be defined through parts or part sets, segment +or node sets will not gather the correct data. +NOTE: The master surface option of FORCE_TRANSDUC- +ER is only implemented for the PENALTY option +and works only in conjunction with the AUTO- +MATIC_SINGLE_SURFACE contact types, except +as noted in the next remark. +3. A master node set can only be used with the TRANSDUCER_PENALTY option, +and requires that the slave side also be defined via a node set. This allows the +transducer to give correct results for eroding materials. The node sets should +include all nodes that may be exposed as erosion occurs. This option does not +apply to Mortar contacts. +Card 2. + Card 2 +Variable +1 +FS +Type +F +Default +0. +Remarks +2 +FD +F +0. +3 +DC +F +0. +4 +VC +F +0. +5 +6 +7 +VDC +PENCHK +BT +8 +DT +F +F +F +0. +I +0 +0. +1.0E20 + VARIABLE +DESCRIPTION +If OPTION1 is TIED_SURFACE_TO_SURFACE_FAILURE, then +FS +Normal tensile stress at failure. failure occurs if +[ +max(0.0, 𝜎normal) +] +𝐹𝑆 ++ [ +𝜎shear +𝐹𝐷 +] +> 1 +where 𝜎normal and 𝜎shear are the interface normal and shear +stresses. +FD +Shear stress at failure. See FS. +Else +𝜇 +𝑝3 +𝑝2 +𝑝1 +𝑣re +Figure 11-1. Friction coefficient, 𝜇, can be a function of relative velocity and +pressure. See Remarks for FS = 2.0. + VARIABLE +DESCRIPTION +FS +Static coefficient of friction. If FS is > 0 and not equal to 2. The +frictional coefficient is assumed to be dependent on the relative +velocity 𝑣rel of the surfaces in contact according to, +𝜇𝑐 = FD + (FS − FD)𝑒−DC∣𝑣rel∣. +For mortar contact 𝜇𝑐 = FS, i.e., dynamic effects are ignored. The +two other possibilities are: +EQ.-2: If only the one friction table is defined using *DEFINE_- +FRICTION, it will be used and there is no need to de- +fine parameter FD. If more than one friction table is +defined then the Table ID is defined by the FD Parame- +ter below. +EQ.-1: If the frictional coefficients defined in the *PART section +are to be used, set FS to the negative number, -1.0. +WARNING: Please note that the FS = -1.0 and FS = -2.0 +options apply only to contact types: +SINGLE_SURFACE, +AUTOMATIC_GENERAL, +AUTOMATIC_SINGLE_SURFACE, +AUTOMATIC_SINGLE_SURFACE_MORTAR, +AUTOMATIC_NODES_TO_SURFACE, +VARIABLE +DESCRIPTION +AUTOMATIC_SURFACE_TO_SURFACE, +AUTOMATIC_SURFACE_TO_SURFACE_MORTAR, +AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE, +ERODING_SINGLE_SURFACE. +EQ.2: For a subset of SURFACE_TO_SURFACE type contacts +, the variable FD serves +as a table ID . That table speci- +fies two or more values of contact pressure, with each +pressure value in the table corresponding to a curve of +friction coefficient vs. relative velocity. Thus the fric- +tion coefficient becomes a function of pressure and rela- +tive velocity. See Figure 11-1. +FD +Dynamic coefficient of friction. The frictional coefficient is +assumed to be dependent on the relative velocity 𝑣rel of the +surfaces in contact according to, +𝜇𝑐 = FD + (FS − FD)𝑒−𝐷𝐶∣𝑣rel∣ +For mortar contact 𝜇𝑐 = FS, i.e., dynamic effects are ignored. +When FS = -2: +If FS = -2 and more than one friction table is defined, FD is used +to specify friction table to be used. +End If +DC +VC + The frictional coefficient is +Exponential decay coefficient. +assumed to be dependent on the relative velocity 𝑣rel of the +surfaces in contact +𝜇𝑐 = FD + (FS − FD)𝑒−DC∣vrel∣. +For mortar contact 𝜇𝑐 = FS, i.e., dynamic effects are ignored. +Coefficient for viscous friction. This is necessary to limit the +friction force to a maximum. A limiting force is computed +𝐹lim = VC × 𝐴cont. 𝐴cont being the area of the segment contacted +by the node in contact. The suggested value for VC is the yield + where 𝜎0 is the yield stress of the +stress in shear 𝑉𝐶 = +𝜎𝑜 +√3 +contacted material. +VDC +*CONTACT_OPTION1_{OPTION2}_… +DESCRIPTION +Viscous damping coefficient in percent of critical or the coefficient +of restitution expressed as percentage. In order to avoid +in contact, e.g., for sheet forming +undesirable oscillation +simulation, a contact damping perpendicular to the contacting +surfaces is applied. When ICOR, the 6th column of the optional E +card, is not defined or 0, the applied damping coefficient is given +by +𝜉 = +VDC +100 +𝜉crit, +where VDC is an integer (in units of percent) between 0 and 100. +The formula for critical damping is +𝜉crit = 2𝑚𝜔, +where 𝑚 is determined by nodal masses as +𝑚 = min(𝑚slave, 𝑚master), +and 𝜔 is determined from 𝑘, the interface stiffness, according to +𝜔 = √𝑘 +𝑚slave + 𝑚master +𝑚master𝑚slave +. +PENCHK +Small penetration in contact search option. If the slave node +penetrates more than the segment thickness times the factor +XPENE, see *CONTROL_CONTACT, the penetration is ignored +and the slave node is set free. The thickness is taken as the shell +thickness if the segment belongs to a shell element or it is taken as +1/20 of its shortest diagonal if the segment belongs to a solid +element. This option applies to the surface-to-surface contact +algorithms: See Table 11-17 for contact types and more details. +BT +Birth time (contact surface becomes active at this time). +LT.0: Birth time is set to |BT|. When negative, birth time is +followed during the dynamic relaxation phase of the +calculation. After dynamic relaxation has completed, +contact is activated regardless the value of BT. +EQ.0: Birth time is inactive, i.e., contact is always active +GT.0: If DT = -9999, BT is interpreted as the curve or table ID +defining multiple pairs of birth-time/death-time, see +remarks below. Otherwise, if DT > 0, birth time applies +both during and after dynamic relaxation. +DT +Death time (contact surface is deactivated at this time). +VARIABLE +DESCRIPTION +LT.0: If DT = -9999, BT is interpreted as the curve or table ID +defining multiple pairs of birth-time/death-time. Oth- +erwise, negative DT indicates that contact is inactive +during dynamic relaxation. After dynamic relaxation +the birth and death times are followed and set to |BT| +and |DT| respectively. +EQ.0: DT defaults to 1.E+20. +GT.0: DT, the death time, sets the time at which the contact is +deactivated. +Remarks: +The FS = 2 method of specifying the friction coefficient as a function of pressure and +relative velocity is implemented in all contacts for which SOFT = 2. It is recommended +that when FS = 2 and SOFT = 2 are used together, that FNLSCL be set in the range of 0.5 +to 1.0 and DNLSCL be set to 0 (refer to Remark 5 under the description of Optional +Card D for *CONTACT). If sliding is prevalent, DPRFAC = 0.01 on Optional Card C is +also recommended. +When FS = 2 and SOFT = 0 or 1, the following ONE_WAY contacts are recommended. +If sliding is prevalent, DPRFAC = 0.01 is also recommended. +ONE_WAY_SURFACE_TO_SURFACE +(SMP and MPP) +AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE +(MPP only) +FORMING_ONE_WAY_SURFACE_SURFACE_TO_SURFACE +(MPP only) +For SOFT = 0 or 1, FS = 2 is implemented but not advised for the following contacts: +SURFACE_TO_SURFACE +AUTOMATIC_SURFACE_TO_SURFACE +FORMING_SURFACE_TO_SURFACE +(SMP and MPP) +(MPP only) +(MPP only) +A caveat pertaining to the MPP contacts listed above is that the “groupable” option +must not be invoked. See *CONTROL_MPP_CONTACT_GROUPABLE. +For SOFT = 0 or 1, FS = 2 is not implemented in SMP for AUTOMATIC and FORMING +contact types. The static friction coefficient will literally be taken as 2.0 if FS is set to 2 +for these SMP contacts. +If DT = -9999, BT is taken to be the ID of an activation curve defining multiple birth- +times and death-times as ordered (𝑥, 𝑦) pairs. A data point in the activation curve +defines a time slot during which the contact is active. For example, an activation curve +with two data points of (20, 30) and (50, 70) activates the contact when 20 ≤ time ≤ 30 +and when 50 ≤ time ≤ 70. To define separate activation curves for dynamic relaxation +and the subsequent dynamics, BT can be defined as a table containing two activation +curves, one with VALUE = 0 for transient analysis and the other one with VALUE = 1 +for dynamic relaxation, see *DEFINE_TABLE. +Card 3. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SFS +SFM +SST +MST +SFST +SFMT +FSF +VSF +Type +F +F +F +F +F +F +F +F +Default +1. +1. +element +thickness +element +thickness +1. +1. +1. +1. + VARIABLE +DESCRIPTION +SFS +SFM +SST +MST +SFST +Scale factor on default slave penalty stiffness when SOFT = 0 or +SOFT = 2, see also *CONTROL_CONTACT. +Scale factor on default master penalty stiffness when SOFT = 0 or +SOFT = 2, see also *CONTROL_CONTACT. +Optional contact thickness for slave surface (overrides default +contact thickness). This option applies to contact with shell and +beam elements. SST has no bearing on the actual thickness of the +elements; it only affects the location of the contact surface. For +the *CONTACT_TIED_… options, SST and MST below can be +defined as negative values, which will cause the determination of +whether or not a node is tied to depend only on the separation +distance relative to the absolute value of these thicknesses. More +information is given under General Remarks on *CONTACT +following Optional Card E. +Optional contact thickness for master surface (overrides default +contact thickness). This option applies only to contact with shell +elements. For the TIED options, see SST above. +Scale factor applied to contact thickness of slave surface. This +option applies to contact with shell and beam elements. SFST has +no bearing on the actual thickness of the elements; it only affects +the location of the contact surface. SFST is ignored if SST is +nonzero except in the case of MORTAR contact . +SFMT +FSF +VSF +Remarks: +*CONTACT_OPTION1_{OPTION2}_… +DESCRIPTION +Scale factor applied to contact thickness of master surface. This +option applies only to contact with shell elements. SFMT has no +bearing on the actual thickness of the elements; it only affects the +location of the contact surface. SFMT is ignored if MST is +nonzero except in the case of MORTAR contact . +Coulomb friction scale factor. The Coulomb friction value is +scaled as 𝜇𝑠𝑐 = FSF × 𝜇𝑐, see above. +Viscous friction scale factor. If this factor is defined then the +limiting force becomes: 𝐹lim = VSF × VC × 𝐴cont, see above. +The variables FSF and VSF above can be overridden segment by segment on the *SET_- +SEGMENT or *SET_SHELL_OPTION cards for the slave surface only as A3 and A4, +and for the master surface only as A1 and A2. See *SET_SEGMENT and *SET_SHELL_ +OPTION. +Card 4: AUTOMATIC_SURFACE_TIEBREAK +This card 4 is mandatory for: +*CONTACT_AUTOMATIC_SURFACE_TO_SURFACE_TIEBREAK_{OPTION} +*CONTACT_AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE_TIEBREAK_{OPTION} +If the response parameter OPTION below is set to 9 or 11, three damping constants can +be defined for the various failure modes. To do this, set the keyword option to +DAMPING +For OPTION = 7 and OPTION = 9 but for the automatic surface to surface contact only, +the mortar treatment of the tiebreak contact may be activated. This is primarily +intended for implicit analysis and no damping can be used with this option, see also +remarks on mortar contacts. The keyword option for this is +MORTAR +The mortar treatment of tiebreak contact is available only for OPTION = 7 and OP- +TION = 9, and only with surface to surface contact, i.e., neither the ONE_WAY nor the +DAMPING option is compatible with the MORTAR option. + Card 4a +1 +2 +3 +4 +5 +6 +7 +8 +Variable +OPTION +NFLS +SFLS +PARAM +ERATEN +ERATES +CT2CN +CN +Type +I +F +F +F +F +F +F +F +Default +required required required +0.0 +0.0 +0.0 +1.0 +0.0 +Damping Card. Additional card for the case of OPTION = 9 with the DAMPING +keyword option active. + Card 4b +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DMP_1 +DMP_2 +DMP_3 +Type +F +F +F +Default +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +OPTION +Response: +EQ.-3: see 3, moments are transferred. SMP only. +EQ.-2: see 2, moments are transferred. SMP only. +EQ.-1: see 1, moments are transferred. SMP only. +EQ.1: slave nodes in contact and which come into contact will +permanently stick. Tangential motion is inhibited. +EQ.2: +tiebreak is active for nodes which are initially in +contact. Until failure, tangential motion is inhibited. If +PARAM is set to unity, (1.0) shell thickness offsets are +ignored, and the orientation of the shell surfaces is re- +quired such that the outward normals point to the op- +posing contact surface. +EQ.3: as 1 above but with failure after sticking. +EQ.4: +EQ.5: +tiebreak is active for nodes which are initially in contact +but tangential motion with frictional sliding is permit- +ted. +tiebreak is active for nodes which are initially in +contact. Stress is limited by the yield condition de- +scribed in Remark 5 below. Damage behavior is mod- +eled by a curve which defines normal stress vs. gap +(crack opening). This option can be used to represent +deformable glue bonds. +EQ.6: This option is for use with solids and thick shells only. +Tiebreak is active for nodes which are initially in con- +tact. Failure stress must be defined for tiebreak to oc- +cur. After the failure stress tiebreak criterion is met, +damage is a linear function of the distance C between +VARIABLE +DESCRIPTION +points initially in contact. When the distance is equal to +PARAM, damage is fully developed and interface fail- +ure occurs. After failure, this option behaves as a sur- +face-to-surface contact. +EQ.7: Dycoss Discrete Crack Model. “…_ONE_WAY_SUR- +FACE_TO_SURFACE_TIEBREAK” definition is rec- +ommended for this option. See Remarks. +EQ.8: This is similar to OPTION = 6, but it works with offset +shell elements. “…_ONE_WAY_SURFACE_TO_SUR- +FACE_TIEBREAK” definition is recommended for this +option. +EQ.9: Discrete Crack Model with power law and B-K damage +models. “…_ONE_WAY_SURFACE_TO_SURFACE_- +TIEBREAK” definition is recommended for this option. +See Remarks. +EQ.10: This is similar to OPTION = 7, but it works with offset +shell elements. “…_ONE_WAY_SURFACE_TO_SUR- +FACE_TIEBREAK” definition is recommended for this +option. +EQ.11: This is similar to OPTION = 9, but it works with offset +shell elements. “…_ONE_WAY_SURFACE_TO_SUR- +FACE_TIEBREAK” definition is recommended for this +option. +Normal failure stress for OPTION = 2, 3, 4, 6, 7, 8, 9, 10 or 11. For +OPTION = 5 NFLS becomes the plastic yield stress as defined in +Remark 5. For OPTION = 9 or 11 and NFLS < 0, a load curve +ID = -NFLS is referenced defining normal failure stress as a +function of element size. See remarks. +Shear failure stress for OPTION = 2, 3, 6, 7, 8, 9, 10 or 11. For +OPTION = 4, SFLS is a frictional stress limit if PARAM = 1. This +frictional stress limit is independent of the normal force at the tie. +For OPTION = 5 SFLS becomes the curve ID which defines +normal stress vs. gap. For OPTION = 9 or 11 and SFLS < 0, a +load curve ID = -SFLS is referenced defining shear failure stress as +a function of element size. See remarks. +NFLS +SFLS +PARAM +For OPTION = 2, setting PARAM = 1 causes the shell thickness +offsets to be ignored. For OPTION = 4, setting PARAM = 1 +causes SFLS to be a frictional stress limit. For OPTION = 6 or 8, +VARIABLE +DESCRIPTION +ERATEN +ERATES +CT2CN +CN +PARAM is the critical distance, CCRIT, at which the interface +failure is complete. For OPTION = 7 or 10 PARAM is the friction +angle in degrees. For OPTION = 9 or 11, it is the exponent in the +damage model. A positive value invokes the power law, while a +negative one, the B-K model. See MAT_138 for additional details. +For OPTION = 7, 9, 10, 11 only. Normal energy release rate +(stress × length) used in damage calculation, see Lemmen and +Meijer [2001]. +For OPTION = 7, 9, 10, 11 only. Shear energy release rate (stress × +length) used in damage calculation, see Lemmen and Meijer +[2001]. +The ratio of the tangential stiffness to the normal stiffness for +OPTION = 9, 11. The default is 1.0. +Normal stiffness (stress/length) for OPTION = 9, 11, and +OPTION = 7 for the MORTAR option only. If CN is not given +explicitly, penalty stiffness divided by segment area is used +(default). This optional stiffness should be used with care, since +contact stability can get affected. A warning message with a +recommended time step is given initially. +DMP_1 +Mode I damping force per unit velocity per unit area. +DMP_2 +Mode II damping force per unit velocity per unit area. +DMP_3 +Mode III damping force per unit velocity per unit area. +Remarks: +1. After failure, this contact option behaves as a surface-to-surface contact with +thickness offsets. After failure, no interface tension is possible. +2. The soft constraint option with SOFT = 2 is not implemented for the tiebreak +option. +3. For OPTION = 2, 3, and 6 the tiebreak failure criterion has normal and shear +components: +( +|𝜎𝑛 | +NFLS +) ++ ( +∣𝜎𝑠∣ +SFLS +) +≥ 1. +4. For OPTION = 4, the tiebreak failure criterion has only a normal stress +component: +|𝜎𝑛| +NFLS +≥ 1. +5. For OPTION = 5, the stress is limited by a perfectly plastic yield condition. For +ties in tension, the yield condition is +For ties in compression, the yield condition is +√𝜎𝑛 +2 + 3∣𝜎𝑠∣2 +NLFS +≤ 1. +√3∣𝜎𝑠∣2 +NLFS +≤ 1. +The stress is also scaled by the damage function which is obtained from the +load curve. For ties in tension, both normal and shear stress are scaled. For ties +in compression, only shear stress is scaled. +6. For OPTION = 6 or 8, damage initiates when the stress meets the failure +criterion. The stress is then scaled by the damage function. Assuming no load +reversals, the energy released due to the failure of the interface is approximate- +ly 0.5 × S × CCRIT, where +𝑆 = √max(𝜎𝑛, 0)2 + ∣𝜎𝑠∣2 +at the initiation of damage. This interface may be used for simulating crack +propagation. For the energy release to be correct, the contact penalty stiffness +must be much larger than +min(NFLF, SFLS) +. +CCRIT +7. OPTION = 7 or 10 is the Dycoss Discrete Crack Model as described in Lemmen +and Meijer [2001]. The relation for the crack initiation is given as +[ +max(𝜎𝑛, 0) +NFLS +] ++ [ +𝜎𝑠 +SFLS − sin(PARAM)min(0, 𝜎𝑛) +] += 1. +8. OPTION = 9 or 11 is based on the fracture model in the cohesive material model +*MAT_COHESIVE_MIXED_MODE, where the model is described in detail. +Failure stresses/peak tractions NFLS and/or SFLS can be defined as functions +of characteristic element length (square root of master segment area) via load +curve. This option is useful to get nearly the same global responses (e.g. load- +displacement curve) with coarse meshes compared to a fine mesh solution. In +general, lower peak tractions are needed for coarser meshes. See also *MAT_- +138. +9. For OPTIONs 6 thru 11 of *CONTACT_AUTOMATIC_ONE_WAY_SUR- +FACE_TO_SURFACE_TIEBREAK, one can determine the condition of the tie- +break surface via the component labeled "contact gap" in the intfor database +(*DATABASE_BINARY_INTFOR). The "contact gap" actually represents a +damage value ranging from 0 (tied, no damage) to 1 (released, full damage). +10. Tying in the AUTOMATIC_..._TIEBREAK contacts occurs if the slave node is +within a small tolerance of the master surface after taking into account contact +thicknesses. For MPP, the tolerance is given by +tol = 0.01√2 × master segment area +for SMP, the tolerance is 0.4(slave contact thickness + master contact thickness). +11. It is recommended that the slave and master sides of tiebreak contact be defined +using segment sets rather than part IDs or part set IDs. In this way, the user can +be more selective in choosing which segments are to be tied and ensure that +contact stresses calculated from nodal contact forces are not diluted by seg- +ments that are not actually on the actual contact surface. The user also has +direct control over the contact segment normal vectors when segment sets are +used. Segment normal vectors should point toward the opposing contact sur- +face so that tension is properly distinguished from compression. +Card 4: AUTOMATIC_SURFACE_TO_SURFACE_COMPOSITE +This card 4 is mandatory for: +*CONTACT_AUTOMATIC_SURFACE_TO_SURFACE_COMPOSITE + Card 4a +1 +2 +3 +4 +Variable +TFAIL +MODEL +CIDMU +CIDETA +Type +F +I +I +I +5 +D +F +Default +required required required required +0.0 +6 +7 +VARIABLE +DESCRIPTION +TFAIL +Tensile traction 𝜎𝑓 required for failure. +MODEL +Model for shear response. See the equations in the Remarks for +details. +EQ.1: limiting shear stress depends on CIDMU in both tension +and compression. See remark 3. +EQ.2: limiting shear stress depends on CIDETA in tension and +CIDMU in compression. See remark 4. +EQ.3: limiting shear stress depends on CIDETA in both tension +and compression. See remark 5. +CIDMU +Curve ID for the coefficient of friction 𝜇(𝐻) as a function of the +Hershey number 𝐻. +CIDETA +Curve ID for the viscosity 𝜂(𝑇) as a function of temperature 𝑇. +D +Composite film thickness. +Remarks: +1. This contact model is designed for simulating the processing of laminated +composite materials. Surfaces in contact may support shear up to the limit +defined by MODEL and be in compression or in tension up to the tensile limit +𝜎𝑓 defined by TFAIL. After TFAIL is reached, the contact fails in both tension +and shear. If the surfaces come back into contact, the bonding heals, and the +contacting surfaces may support shear and tension. +2. The viscosity 𝜂(𝑇) is defined as a function of temperature by CIDETA. The +value of the viscosity is not extrapolated if the temperature falls outside of the +temperature range defined by the curve. +3. The coefficient of friction 𝜇 for MODEL = 1 is defined in terms of the Hershey +number 𝐻 = 𝜂(𝑇)𝑉/(𝑝 + 𝜎𝑓 ) where p is the contact pressure (positive in com- +pression, and negative in tension) and V the relative velocity between the sur- +faces. +𝜏 ≤ μ(𝐻)(𝑝 + 𝜎𝑓 ) +4. The coefficient of friction 𝜇 for MODEL = 2 is defined in terms of the Hershey +number 𝐻 = 𝜂(𝑇)𝑉/𝑝. Note the definition of the Hershey number for this +model differs from MODEL = 1. In compression the shear stress is limited by +𝜏 ≤ μ(𝐻)𝑝 +and in tension, the shear stress is limited according to +𝜏 ≤ 𝜂(𝑇)𝑉/𝑑 +5. The shear stress for MODEL = 3 in tension and compression is limited +according to +𝜏 ≤ 𝜂(𝑇)𝑉/𝑑. +Card 4: SINGLE_SURFACE_TIED +This card 4 is mandatory for: +*CONTACT_AUTOMATIC_SINGLE_SURFACE_TIED + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CLOSE +Type +F +Default +0.0 + VARIABLE +CLOSE +Remarks: +DESCRIPTION +Surfaces closer than CLOSE are tied. If CLOSE is left as 0.0, it is +defaulted to one percent of the mesh characteristic length scale. +Nodes that are above or below the surface will be tied if they are +close enough to the surface. +This special feature is implemented to allow for the calculation of eigenvalues and +eigenvectors on geometries that are connected by a contact interface using the AUTO- +MATIC_SINGLE_SURFACE options. +If there is significant separation between the tied surfaces, the rigid body modes will be +opposed by the contact stiffness, and the calculated eigenvalues for rigid body rotations +will not be zero. +Card 4: AUTOMATIC_SURFACE_TO_SURFACE_TIED_WELD +This card 4 is mandatory for: +*CONTACT_AUTOMATIC_SURFACE_TO_SURFACE_TIED_WELD + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TEMP +CLOSE +Type +F +F +Default +None +0.0 +DESCRIPTION +Minimum temperature required on both surfaces for tying. Once +the surfaces are tied, they remain tied even if the temperature +drops. +Surfaces closer than CLOSE are tied. If CLOSE is left as 0.0, it is +defaulted to one percent of the mesh characteristic length scale. +Nodes that are above or below the surface will be tied if they are +close enough to the surface. + VARIABLE +TEMP +CLOSE +Remarks: +This special feature is implemented to allow for the simulation of welding. As regions +of the surfaces are heated to the welding temperature and come into contact, the nodes +are tied. +If there is significant separation between the tied surfaces, the rigid body modes will not +be opposed by the contact stiffness. In other words, the offset between the surfaces is +handled like the contact with OFFSET. +If the surfaces are below the welding temperature, the surfaces interact with the +standard AUTOMATIC_SURFACE_TO_SURFACE options. +Card 4: CONSTRAINT_…_TO_SURFACE +This card 4 is mandatory for: +*CONTACT_CONSTRAINT_NODES_TO_SURFACE +*CONTACT_CONSTRAINT_SURFACE_TO_SURFACE + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +KPF +Type +F +Default +0.0 + VARIABLE +DESCRIPTION +KPF +Kinematic partition factor for constraint: +EQ.0.0: fully symmetric treatment. +EQ.1.0: one way treatment with slave nodes constrained to +master surface. Only the slave nodes are checked +against contact. +EQ.-1.0: one way treatment with master nodes constrained to +slave surface. Only the master nodes are checked +against contact. +Card 4: DRAWBEAD +This card 4 is mandatory for: +*CONTACT_DRAWBEAD +*CONTACT_DRAWBEAD_INITIALIZE +Note variables related to automatic multiple draw bead feature, including NBEAD, +POINT1, POINT2, WIDTH, and EFFHGT are not applicable to *CONTACT_DRAW- +BEAD_INITIALIZE. + Card 4a +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCIDRF +LCIDNF +DBDTH +DFSCL +NUMINT +DBPID +ELOFF +NBEAD +Type +I +I +F +F +Default +required none +0.0 +1.0 +I +0 +I +0 +I +0 +I +none +Additional card to be included if NBEAD is defined. + Card 4b +1 +2 +3 +4 +5 +6 +7 +8 +Variable +POINT1 +POINT2 WIDTH +EFFHGT +Type +I +I +F +F +Default +none +none +none +none += Ffriction + + Fbending +DBDTH +Figure 11-2. The draw bead contact model. +Initialization Card. Additional card for INITIALIZE keyword option. Card to initialize +the plastic strain and thickness of elements that pass under the draw bead. + Card 4c +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCEPS +TSCALE +LCEPS2 +OFFSET +Type +I +F +I +F +Default +required +1.0 +optional optional + VARIABLE +LCIDRF +LCIDNF +DESCRIPTION +If LCIDRF is positive then it defines the load curve ID giving the +bending component of the restraining force, Fbending, per unit +draw bead length as a function of displacement, 𝛿, see Figure +11-2. This force is due to the bending and unbending of the blank +as it moves through the draw bead. The total restraining force is +the sum of the bending and friction components. +If LCIDRF is negative, then the absolute value gives the load +curve ID defining max bead force versus normalized draw bead +length. The abscissa values are between zero and 1 and are the +normalized draw bead length. The ordinate gives the maximum +allowed draw bead, retaining force when the bead is in the fully +closed position. If the draw bead is not fully closed, linear +interpolation is used to compute the draw bead force. +Load curve ID giving the normal force per unit draw bead length +as a function of displacement, 𝛿, see Figure 11-2. +This force originates from bending the blank into the draw bead +as the binder closes on the die. The normal force begins to +develop when the distance between the die and binder is less +than the draw bead depth. As the binder and die close on the +blank this force should diminish or reach a plateau. +DBDTH +DFSCL +NUMINT +DBPID +ELOFF +*CONTACT_OPTION1_{OPTION2}_… +DESCRIPTION +Draw bead depth, see Figure 11-2. Necessary to determine +correct 𝛿 displacement from contact displacements. +Scale factor for load curve. Default = 1.0. This factor scales load +curve ID, LCIDRF above. +Number of equally spaced integration points along the draw +bead: +EQ.0: Internally calculated based on element size of elements +that interact with draw bead. +This is necessary for the correct calculation of the restraining +forces. More integration points may increase the accuracy since +the force is applied more evenly along the bead. +Optional part ID for the automatically generated truss elements +for the draw bead display in the post-processor. If undefined LS- +DYNA assigns a unique part ID. +Option to specify and element ID offset for the truss elements that +are automatically generated for the draw bead display. If +undefined LS-DYNA chooses a unique offset. +NBEAD +Number of line beads in odd integer. +POINT1 +Node ID of the first node on a binder. +POINT2 +Node ID of a matching node on the opposing binder. +WIDTH +EFFHGT +LCEPS +Total bead width defining distance between inner and outer most +bead walls. +Effective bead height. Draw bead restraining force starts to take +effect when binder gap is less than EFFHGT. +through +thickness. +the shell +Load curve ID defining the plastic strain versus the parametric +coordinate + The parametric +coordinate should be defined in the interval between -1 and 1 +inclusive. The value of plastic strain at the integration point is +interpolated from this load curve. If the plastic strain at an +integration point exceeds the value of the load curve at the time +initialization occurs, the plastic strain at the point will remain +unchanged. +VARIABLE +TSCALE +LCEPS2 +DESCRIPTION +Scale factor that multiplies the shell thickness as the shell element +moves under the draw bead. +Optional load curve ID defining the plastic strain versus the +parametric coordinate through the shell thickness, which is used +after an element has traveled a distance equal to OFFSET. The +parametric coordinate should be defined in the interval between - +1 and 1 inclusive. The value of plastic strain at the integration +point is interpolated from this load curve. If the plastic strain at +an integration point exceeds the value of the load curve at the +time initialization occurs, the plastic strain at the point will +remain unchanged. Input parameters LCEPS2 and OFFSET +provides a way to model the case where a material moves under +two draw beads. In this latter case the curve would be the sum of +the plastic strains generate by moving under two consecutive +beads. +OFFSET +If the center of an element has moved a distance equal to OFFSET, +the load curve ID, LCEPS2 is used to reinitialize the plastic strain. +The TSCALE scale factor is also applied. +Overview: +In the framework of this draw bead model the blank is the master part, and the male +part of the draw bead is the slave. The male part of the draw bead, which moves with +the punch, is input as a curve defined using a list of nodes or a part consisting of beams, +as discussed below. Associated with this curve is a region of influence that is +characterized by the DBDTH field of card 4a. +As the punch comes down and the region of influence intersects the elements on the +blank, forces are applied to the blank at the points of closest approach. These forces +depend on the separation distance, 𝛿, which is geometrically defined in Figure 11-2. +The draw bead force model consists of two terms: +6. There is a resisting force, which is a function of 𝛿, and is defined through the +load curve specified in the LCIDRF field. This force is applied in a direction +opposite to velocity. +7. There is also a normal force pushing the male part of the draw bead away from +the blank, which is specified by LCIDNF. This normal force, in turn, is used to +model friction, which depends on the product of the friction coefficient and the +normal force. +The curve representing the male part of the draw bead can be defined in three ways: +1. A consecutive list of slave nodes that lie along the bead. +2. A part ID of a beam that lies along the draw bead. +3. A part set ID of beams that lie along the draw bead. +For straight draw beads, only two nodes or a single beam needs to be defined, i.e., one +at each end. For curved beads, many nodes or beams may be required to define the +curvature of the bead geometry. +When beams are used to define the bead, with the exception of the first and last node, +each node must connect with two beam elements. This requirement means that the +number of slave nodes equals the number of beam elements plus one. +It is at the integration points where the contact algorithm checks for penetration. +Integration points are equally spaced along the draw bead and do not depend on the +nodal spacing used in the definition of the draw bead. By using the capability of tying +extra nodes to rigid bodies the draw bead nodal points do not need to belong to the +element connectivities of the die and binder. The blank makes up the master surface. +NOTE: It is highly recommended to define a BOXID around +the draw bead to limit the size of the master surface +considered for the draw bead. This will substantially +reduce cost and memory requirements. +LS-PrePost: +While defining a contact draw bead may involve several keywords, the processed is +streamlined by the “draw bead” definition feature of LS-PrePost4.0’s eZ-Setup for metal +forming application. See, +http://ftp.lstc.com/anonymous/outgoing/lsprepost/4.0/metalforming/ +Multiple draw beads model: +Developed in conjunction with the Ford Motor Company Research & Advanced Engineering +Laboratory, the multiple draw bead features provides a simple way to model (1) the +neglected effects of the draw bead width, and (2) to attenuate the bead forces when the +distance between upper and lower binders is more than the draw bead height. +1. Draw Bead Width Correction. As shown in Figure 11-3, it often happens that +a sheet blank edge does not cross the draw bead’s curve of definition but does +fall within its width. When the bead is modelled as a 1-dimensional (no width) +curve, it is possible that a major portion of the blank would have no forces +applied, while, in reality, there are still two bending radii at the inner bead wall +providing about 50% of the total bead forces. The neglect of width effects leads +to excessive blank edge draw-ins resulting in either loose metal in the part, or +wrinkles on the draw wall or product surface. +The multiple beads feature ameliorates this particular shortcoming by replacing +the single 1-dimensional bead with an equivalent set of beads distributed over +the width of the physical bead. The bead force is distributed uniformly over the +NBEAD sub-beads, such that the resultant force is equal to that of the original +1-dimensionsal bead. Note that NBEAD must be an odd integer. +Figure 11-4 schematically represents the NBEAD = 3 case for which two addi- +tional line beads are automatically generated. The forces specified by the load +curve, LCIDRF, will be evenly distributed over the 3 beads. In Figure 11-5, +bead forces are recovered from the ASCII rcforc files for both cases of +NBEAD = 1 and 3, indicating the total force applied (shown on the left) on one +single bead is distributed evenly among the three automatically generated +beads for the case of NBEAD = 3. +The stress distribution is also more realistic with the multiple beads. In a chan- +nel draw (half model) as shown in Figure 11-9, no significant changes in mean +stress values are found between NBEAD = 3 and one single line bead. In fact, +the compressive stresses are more realistically and evenly distributed around +the bead region, with stresses in NBEAD = 3 about 1/3 of those in one line +bead. +2. Lower Binder Gap Correction. As originally implemented, the draw bead +contact model applies the draw bead forces, as specified in the load curve, +when the upper binder reaches the blank, regardless of the lower binder’s posi- +tion. If the lower binder is not in contact with the blank, LS-DYNA still applies +draw bead forces, even though it is unphysical to do so. The EFFHGT, POINT1 +and POINT2 fields together provide a simple model to avoid these unphysical +forces. The POINT1 and POINT2 fields are taken as nodes on the opposing +binders. The draw bead contact is disabled when the Euclidean distance be- +tween POINT1 and POINT2 is greater than EFFHGT; consequently, the two +nodes must be chosen so they converge to a single point as the draw bead clos- +es. +As shown in Figure 11-6, a simple model was built to verify the effectiveness of +the variable EFFHGT. The upper binder is pushed down to close with the low- +er binder while a strip of sheet blank is being pulled in the direction indicated. +The distance between the binders is 12mm initially, as shown in Figure 11-7, +and the closing gap and pulling force in x were recovered throughout the simu- +lation. With the EFFHGT set at 8mm, the pulling force history indicates the +bead forces starting to take effect after the upper binder has traveled for 4mm, +Figure 11-8, as expected. +Revision information: +The NBEAD feature is available in LS-DYNA R6 Revision 69556 and later releases, with +important updates in Revision 79270. +Inner bead wall +Blank edge flow direction +Blank drawn edge +Outer bead wall +Location of a single line bead force +Figure 11-3. A possible scenario of sheet blank edge draw-in condition. +Auto-created beads +Defined node set/beam +WIDTH +5.25 +5.25 +EFFHGT +Figure 11-4. Definition of multiple draw beads. +) +( +14 +12 +10 +-2 +0.002 +0.004 +min=-7.3006 +max=13559 +~13559N +Legend + rcforc bead 1 +0.008 +0.01 +0.006 +Time +) +( +-1 +0.002 +0.004 +min=27.946 +max=4523.8 +~4523N +Legend + rcforc bead 1 + rcforc bead 2 + rcforc bead 3 +0.008 +0.01 +0.006 +Time +Figure 11-5. Bead force verification between NBEAD = 1 (left) and 3. +Bead #3 +Bead #5 +Bead #4 +(Beads attached to +the upper binder) +Details in +next figure +Figure 11-6. A verification model for the variable EFFHGT. +POINT1(node) +Draw beads +Sheet strip +Upper binder +12mm +Tracking binder closing gap as +abscissa values +Pull in X +Tracking the pulling force +in X as ordinate values +POINT2 (node) +Lower binder +Figure 11-7. Tracking the closing gap and pulling distance. +200 +150 +100 +50 +) +( +-50 +-12 +Bead force starts taking effect +at a distance of 8.0mm +-10 +-8 +-6 +-4 +-2 +Closing distance (mm) +Figure 11-8. Pulling force (NODFOR) vs. closure distance. +Time=0.0152, #nodes=7005, #elem=6503 +Contours of pressure (mid-plane) +min=-395.339, at elem# 15423 +max=28.1887, at elem# 13317 +Time=0.0152, #nodes=6976, #elem=6476 +Contours of pressure (mid-plane) +min=-401.24, at elem# 15280 +max=74.6163, at elem# 13016 +Pressure (MPa) +28.2 +Pressure (MPa) +74.6 +-14.2 +-56.5 +-98.9 +-141.2 +-183.6 +-225.9 +-268.3 +-310.6 +-353.0 +-395.3 +27.0 +-20.6 +-68.1 +-115.7 +-163.3 +-210.9 +-258.5 +-306.1 +-353.7 +-401.2 +Mean stresses of a channel draw +(NBEAD=3) +Mean stresses of a channel draw +on one line bead +Figure 11-9. Mean stress comparison between NBEAD = 3 and 1. +Card 4: ERODING_..._SURFACE +This card 4 is mandatory for: +*CONTACT_ERODING_NODES_TO_SURFACE +*CONTACT_ERODING_SINGLE_SURFACE +*CONTACT_ERODING_SURFACE_TO_SURFACE + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ISYM +EROSOP +IADJ +Type +Default +I +0 +I +0 +I +0 + VARIABLE +DESCRIPTION +ISYM +Symmetry plane option: +EQ.0: off, +EQ.1: do not include faces with normal boundary constraints +(e.g., segments of brick elements on a symmetry plane). +This option is important to retain the correct boundary conditions +in the model with symmetry. +EROSOP +Erosion/Interior node option: (reset to 1 internally) +EQ.0: only exterior boundary information is saved, +EQ.1: storage is allocated so that eroding contact can occur. +Otherwise, no contact is assumed after erosion of the +corresponding element. +IADJ +Adjacent material treatment for solid elements: (reset to 1 +internally) +EQ.0: solid element faces are included only for free bounda- +ries, +EQ.1: solid element faces are included if they are on the +boundary of the material subset. This option also allows +the erosion within a body and the subsequent treatment +of contact. +*CONTACT_OPTION1_{OPTION2}_… +Eroding contact may control the timestep . For +ERODING_NODES_TO_SURFACE, define the slave side using a node set, not a part ID +or part set ID. +Use of an ERODING contact automatically invokes a negative volume failure criterion +in +for all solid elements +*CONTROL_SOLID. Use of PSFAIL will limit the negative volume failure criterion to a +set of solid parts. A negative volume failure criterion circumvents an error termination +due to negative volume by deleting solid elements that develop negative volume. +the model, except as overridden by PSFAIL +in +Contact friction is not considered by SMP LS-DYNA for *CONTACT_ERODING_- +NODES_TO_SURFACE and *CONTACT_ERODING_SURFACE_TO_SURFACE unless +SOFT is set to 2 on Optional Card A. MPP LS-DYNA has no such exclusion for contact +friction. +Values of EROSOP = 0 and IADJ = 0 are not supported, and both are reset to 1 +internally. +Card 4: SURFACE_INTERFERENCE +This card 4 is mandatory for: +*CONTACT_NODES_TO_SURFACE_INTERFERENCE +*CONTACT_ONE_WAY_SURFACE_TO_SURFACE_INTERFERENCE +*CONTACT_SURFACE_TO_SURFACE_INTERFERENCE +Purpose: This contact option provides a means of modeling parts which are shrink +fitted together and are, therefore, prestressed in the initial configuration. This option +turns off the nodal interpenetration checks (which changes the geometry by moving the +nodes to eliminate the interpenetration) at the start of the simulation and allows the +contact forces to develop to remove the interpenetrations. The load curves defined in +this section scale the interface stiffness constants such that the stiffness can increase +slowly from zero to a final value with effect that the interface forces also increase +gradually to remove the overlaps. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCID1 +LCID2 +Type +Default +I +0 +I +0 +DESCRIPTION +Load curve ID which scales the interface stiffness during dynamic +relaxation. This curve must originate at (0, 0) at time = 0 and +gradually increase. +Load curve ID which scales the interface stiffness during the +transient calculation. This curve generally has a constant value of +unity for the duration of the calculation if LCID1 is defined. If +LCID1 = 0, this curve must originate at (0, 0) at time = 0 and +gradually increase to a constant value. + VARIABLE +LCID1 +LCID2 +Remarks: +1. Shell thickness offsets are taken into account for deformable shell elements. +2. The check to fix initial penetrations is skipped. +3. Automatic orientation of shell elements is skipped. +4. Furthermore, segment orientation for shell elements and interpenetration +checks are skipped. +Therefore, it is necessary in the problem setup to ensure that all contact segments which +belong to shell elements are properly oriented, i.e., the outward normal vector of the +segment based on the right hand rule relative to the segment numbering, must point to +the opposing contact surface; consequently, automatic contact generation should be +avoided for parts composed of shell elements unless automatic generation is used on +the slave side of a nodes to surface interface. +Card 4: RIGID_TO_RIGID +This card 4 is mandatory for: +*CONTACT_RIGID_NODES_TO_RIGID_BODY +*CONTACT_RIGID_BODY_ONE_WAY_TO_RIGID_BODY +*CONTACT_RIGID_BODY_TWO_WAY_TO_RIGID_BODY + Card 4 +1 +2 +Variable +LCID +FCM +Type +I +I +3 +US +F +4 +5 +6 +7 +8 +LCDC +DSF +UNLCID +I +F +I +Default +required required LCID +optional +0.0 +optional + VARIABLE +LCID +DESCRIPTION +Load curve ID giving force versus penetration behavior for +RIGID_contact. See also the definition of FCM below. +FCM +Force calculation method for RIGID_contact: +EQ.1: Load curve gives total normal force on surface versus +maximum penetration of any node (RIGID_BODY_- +ONE_WAY only). +EQ.2: Load curve gives normal force on each node versus +penetration of node through the surface (all RIG- +ID_contact types). +EQ.3: Load curve gives normal pressure versus penetration of +node through the surface (RIGID_BODY_TWO_WAY +and RIGID_BODY_ONE_WAY only). +EQ.4: Load curve gives total normal force versus maximum +soft penetration. In this case the force will be followed +based on the original penetration point. (RIGID_- +BODY_ONE_WAY only). +US +Unloading stiffness for RIGID_contact. The default is to unload +along the loading curve. This should be equal to or greater than +the maximum slope used in the loading curve. +Loading Curve +Unloading +Stiffness +Unloading Curve +Penetration + VARIABLE +LCDC +Figure 11-10. Behavior if an unloading curve is defined +DESCRIPTION +(DC) versus +ID giving damping coefficient +Load curve +penetration velocity. The damping force FD is then: FD = DSF × +DC × velocity. +DSF +Damping scaling factor. +UNLCID +Optional load curve ID giving force versus penetration behavior +for RIGID_BODY_ONE_WAY contact. This option requires the +definition of the unloading stiffness, US. See Figure 11-10. +Card 4: TIEBREAK_NODES +This card 4 is mandatory for: +*CONTACT_TIEBREAK_NODES_TO_SURFACE and +*CONTACT_TIEBREAK_NODES_ONLY + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NFLF +SFLF +NEN +MES +Type +F +F +F +Default +required required +2. +F +2. + VARIABLE +DESCRIPTION +Normal failure force. Only tensile failure, i.e., tensile normal +forces, will be considered in the failure criterion. +Shear failure force +Exponent for normal force +Exponent for shear force. Failure criterion: +( +∣𝑓𝑛∣ +NFLF +NEN +) ++ ( +∣𝑓𝑠∣ +SFLF +MES +) +≥ 1. +Failure is assumed if the left side is larger than 1. 𝑓𝑛 and 𝑓𝑠 are the +normal and shear interface force. +NFLF +SFLF +NEN +MES +Remarks: +These attributes can be overridden node by node on the *SET_NODE_option cards. +Both NFLF and SFLF must be defined. If failure in only tension or shear is required +then set the other failure force to a large value (1E+10). +After failure, contact_tiebreak_nodes_to_surface behaves as a nodes-to-surface contact +with no thickness offsets (no interface tension possible) whereas the contact_tiebreak_ +nodes_only stops acting altogether. Prior to failure, the two contact types behave +identically. +Card 4: TIEBREAK_SURFACE +This card 4 is mandatory for: +*CONTACT_TIEBREAK_SURFACE_TO_SURFACE and +*CONTACT_TIEBREAK_SURFACE_TO_SURFACE_ONLY + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NFLS +SFLS +TBLCID +THKOFF +Type +F +F +I +Default +required required +0 +I +0 + VARIABLE +DESCRIPTION +NFLS +SFLS +Tensile failure stress. See remark below. +Shear failure stress. Failure criterion +( +|𝜎𝑛| +NFLS +) ++ ( +) +∣𝜎𝑠∣ +SFLS +≥ 1. +Optional load curve number defining the resisting tensile stress +versus gap opening in the normal direction for the post failure +response. This option applies only to SMP and can be used to +model adhesives. +Thickness offsets are considered if THKOFF = 1. If shell offsets +are included in the meshed geometry, this option is highly +recommended since segment orientation can be arbitrary and the +contact surfaces can be disjoint. This option is not available in the +MPP version of LS-DYNA. It works by substituting *CON- +TACT_AUTOMATIC_SURFACE_TO_SURFACE_TIEBREAK +(OPTION = 2 if TBLCID is not specified; OPTION = 5 if TBLCID +is specified). +TBLCID +THKOFF +Remarks: +The failure attributes can be overridden segment by segment on the *SET_SEGMENT or +*SET_SHELL_option cards for the slave surface as A1 and A2. These variables do not +apply to the master surface. Both NFLS and SFLS must be defined. If failure in only +tension or shear is required then set the other failure stress to a large value (1E+10). +When used with shells, contact segment normals are used to establish the tension +direction (as opposed to compression). Compressive stress does not contribute to the +failure equation. +After failure, *CONTACT_TIEBREAK_SURFACE_TO_SURFACE behaves as a surface- +to-surface contact with no thickness offsets. +After failure, *CONTACT_TIEBREAK_SURFACE_TO_SURFACE_ONLY stops acting +altogether. Until failure, it ties the slave nodes to the master nodes. +Card 4: CONTRACTION_JOINT +This card 4 is mandatory for: +*CONTACT_SURFACE_TO_SURFACE_CONTRACTION_JOINT +Purpose: This contact option turns on the contraction joint model designed to simulate +the effects of sinusoidal joint surfaces (shear keys) in the contraction joints of arch dams +and other concrete structures. The sinusoidal functions for the shear keys are defined +according to the following three methods [Solberg and Noble 2002]: +Method 1: +Method 2: +Method 3: (default) +𝑔̂ = 𝑔 − 𝐴{1 − cos[𝐵(𝑠2 − 𝑠1)]} +𝑔̂ = 𝑔 − 2𝐴 ∣sin [ +𝐵(𝑠2 − 𝑠1) +]∣ +𝑔̂ = 𝑔 − 𝐴cos(𝐵𝑠2) + 𝐴cos(𝐵𝑠1) +Where 𝑔 is a gap function for contact surface, 𝑔̂ is gap function for the joint surface. 𝐴 is +key amplitude parameter, and 𝐵 is key frequency parameter. 𝑠1 and 𝑠2 are referential +surfaces: +𝑠1 = 𝐗surface1 ⋅ 𝐓key +𝑠2 = 𝐗surface2 ⋅ 𝐓key +𝐓key = 𝐓slide × 𝐧 +Where 𝐓slide is the free sliding direction of the keys, 𝐧 is the surface normal in reference. + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MTCJ +ALPHA +BETA +TSVX +TSVY +TSVZ +Type +Default +I +0 +F +F +F +F +F +0.0 +0.0 +0.0 +0.0 +0.0 +VARIABLE +DESCRIPTION +MTCJ +The method option for the gap function, 𝑔̂ +ALPHA +Key amplitude parameter A +BETA +TSVX +TSVY +TSVZ +Key frequency parameter B +𝑥 component of the free sliding direction 𝐓slide +𝑦 component of the free sliding direction 𝐓slide +𝑧 component of the free sliding direction 𝐓slide +*CONTACT_OPTION1_{OPTION2}_… +This card is mandatory for the THERMAL option, i.e.: +*CONTACT_…_THERMAL_… +Reminder: If Card 4 is required, then it must go before this thermal card. (Card 4 is +required for certain contact types - see earlier in this section for the list, later in this +section for details of Card 4.) +Thermal Card l. + Card 1 +Variable +Type +1 +K +F +2 +FRAD +F +3 +H0 +F +4 +5 +6 +7 +8 +LMIN +LMAX +FTOSLV +BC_FLG +ALGO +F +F +F +I +0 +I +0 +Default +none +none +none +none +none +0.5 + VARIABLE +DESCRIPTION +K +Thermal conductivity of fluid between the contact surfaces. If a +gap with a thickness 𝑙gap exists between the contact surfaces, then +the conductance due to thermal conductivity between the contact +surfaces is +ℎcond = +𝑙gap +Note that LS- DYNA calculates 𝑙gap based on deformation +FRAD +Radiation factor between the contact surfaces. +Where, +𝑓rad = ++ 1 +𝜀2 +𝜀1 +− 1 +𝜎 = Stefan-Boltman constant +𝜀1 = emissivity of master surface +𝜀2 = emissivity of slave surface +LS-DYNA calculates a radiant heat transfer conductance +ℎrad = 𝑓rad(𝑇𝑚 + 𝑇𝑠)(𝑇𝑚 +2 + 𝑇𝑠 +2) +VARIABLE +H0 +DESCRIPTION +Heat transfer conductance for closed gaps. Use this heat transfer +conductance for gaps in the range +0 ≤ 𝑙gap ≤ 𝑙min +LMIN +Minimum gap, 𝑙min, use the heat transfer conductance defined +(H0) for gap thicknesses less than this value. +If 𝑙min < 0, then −𝑙min is a load curve number defining 𝑙min as a +function time. +LMAX +No thermal contact if gap is greater than this value (𝑙max). +FTOSLV +Fraction, 𝑓 , of sliding friction energy partitioned to the slave +surface. Energy partitioned to the master surface is (1 − 𝑓 ). +EQ.0: Default set to 0.5: The +is +sliding +partitioned 50% - 50% to the slave and master surfaces in +contact. +friction +energy +𝑓 = +. +√(𝜌𝐶𝑝𝑘) +1 + +master side material +√(𝜌𝐶𝑝𝑘) +slave side material +BC_FLAG +Thermal boundary condition flag +EQ.0: thermal boundary conditions are on when parts are in +contact +EQ.1: thermal boundary conditions are off when parts are in +contact +ALGO +Contact algorithm type. +EQ.0: two way contact, both surfaces change temperature due +to contact +EQ.1: one way contact, master surface does not change +temperature due to contact. Slave surface does change +temperature. +Remarks: +Note that LS- DYNA calculates 𝑙gap based on deformation +*CONTACT_OPTION1_{OPTION2}_… +ℎ = +⎧ℎ0 +{{ +ℎcond + ℎrad +⎨ +{{ +⎩ +0 ≤ 𝑙gap ≤ 𝑙min +𝑙min < 𝑙gap ≤ 𝑙max +𝑙gap > 𝑙max +THERMAL FRICTION: +This card is required if the FRICTION suffix is added to THERMAL. +*CONTACT_…_THERMAL_FRICTION_… +The blank (or work piece) must be defined as the slave surface in a metal forming +model. +Purpose: +1. Used to define the mechanical static and dynamic friction coefficients as a +function of temperature. +2. Used to define the thermal contact conductance as a function of temperature +and pressure. + Card 1 +1 +2 +3 +Variable +LCFST +LCFDT +FORMULA +Type +Default +I +0 +I +0 +I +0 +4 +A +I +0 +5 +B +I +0. +6 +C +I +0 +7 +D +I +0 +8 +LCH +I +0 +User Subroutine Cards. Additional cards for when FORMULA is a negative number. +Use as many cards as necessary to set |FORMULA| number of parameters. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +UC1 +UC2 +UC3 +UC4 +UC5 +UC6 +UC7 +UC8 +Type +F +F +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + VARIABLE +LCFST +DESCRIPTION +Load curve number for static coefficient of friction as a function of +temperature. The load curve value multiplies the coefficient +value FS. +LCFDT +*CONTACT_OPTION1_{OPTION2}_… +DESCRIPTION +Load curve number for dynamic coefficient of friction as a +function of temperature. The load curve value multiplies the +coefficient value FD. +FORMULA +Formula that defines the contact heat conductance as a function of +temperature and pressure. +EQ.1: ℎ(𝑃) is defined by load curve A, which contains data for +contact conductance as a function of pressure. +EQ.2: ℎ(𝑃) is given by the following where A, B, C and D +although defined by load curves are typically constants +for use in this formula. The load curves are to given as +functions of temperature. +ℎ(𝑃) = 𝑎 + 𝑏𝑃 + 𝑐𝑃2 + 𝑑𝑃3 +EQ.3: ℎ(𝑃) is given by the following formula from [Shvets and +Dyban 1964]. +ℎ(𝑃) = +𝜋𝑘gas +4𝜆 +[1. +85 ( +0.8 +) +] = +[1. +85 ( +0.8 +) +] +where, +a: is evaluated from the load curve, A, for the thermal +conductivity, 𝑘gas, of the gas in the gap as a function +of temperature. +b: is evaluated from the load curve, B, for the parameter +grouping 𝜋/4𝜆. Therefore, this load curve should be +set to a constant value. 𝜆 is the surface roughness. +c: is evaluated from the load curve, C , which specifies a +stress metric for deformation (e.g., yield) as a function +of temperature. +EQ.4: ℎ(𝑃) is given by the following formula from [Li and +Sellars 1996]. +where, +ℎ(𝑃) = 𝑎 [1 − exp (−𝑏 +)] +𝑎: is evaluated from the load curve, A, which defines a +load curve as a function of temperature. +𝑏: is evaluated from the load curve, B, which defines a +load curve as a function of temperature. +VARIABLE +DESCRIPTION +A +B +C +D +LCH +𝑐: is evaluated from the load curve, C, which defines a +stress metric for deformation (e.g., yield) as a function +of temperature. +𝑑: is evaluated from the load curve D, which is a func- +tion of temperature. +EQ.5: ℎ(gap) is defined by load curve A, which contains data +for contact conductance as a function of interface gap. +LT.0: This is equivalent to defining the keyword *USER_IN- +TERFACE_CONDUCTIVITY and the user subroutine +usrhcon will be called for this contact interface for defin- +ing the contact heat transfer coefficient. +Load curve number for the 𝑎 coefficient used in the formula. +Load curve number for the 𝑏 coefficient used in the formula. +Load curve number for the 𝑐 coefficient used in the formula. +Load curve number for the 𝑑 coefficient used in the formula. +Load curve number for ℎ. This parameter can refer to a curve ID + or a function ID . When LCH is a curve ID (and a function ID) it is +interpreted as follows: +GT.0: the heat transfer coefficient is defined as a function of +time, 𝑡, by a curve consisting of (𝑡, ℎ(𝑡)) data pairs. +LT.0: the heat transfer coefficient is defined as a function of +temperature, 𝑇, by a curve consisting of (𝑇, ℎ(𝑇)) data +pairs. +When the reference is to a function it is prototyped as follows +ℎ = ℎ(𝑡, 𝑇avg, 𝑇slv, 𝑇msr, 𝑃, 𝑔) where: +𝑡 = solution time +𝑇avg = average interface temperature +𝑇slv = slave segment temperature +𝑇msr = master segment temperature +𝑃 = interface pressure +𝑔 = gap distance between master and slave segment +*CONTACT_OPTION1_{OPTION2}_… +Additional cards for the ORTHO_FRICTION keyword option: +*CONTACT_…_ORTHO_FRICTION_… + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FS1_S +FD1_S +DC1_S +VC1_S +LC1_S +OACS_S +LCFS +LCPS +Type +F +Default +0. +F +0. +F +0. +F +0. + Card 2 +1 +2 +3 +4 +I +0 +5 +I +0 +6 +I +0 +7 +I +0 +8 +Variable +FS2_S +FD2_S +DC2_S +VC2_S +LC2_S +Type +F +Default +0. + Card 3 +1 +F +0. +2 +F +0. +3 +F +0. +4 +I +0 +5 +6 +7 +8 +Variable +FS1_M +FD1_M +DC1_M +VC1_M +LC1_M OACS_M +LCFM +LCPM +Type +F +Default +0. +F +0. +F +0. +F +0. +I +0 +I +0 +I +0 +I +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FS2_M +FD2_M +DC2_M +VC2_M +LC2_M +Type +F +Default +0. +F +0. +F +0. +F +0. +I +0 +VARIABLE +FSn_S or M +DESCRIPTION +Static coefficient of friction in the local n orthotropic direction for +the slave (S) or master (M) surface. The frictional coefficient is +assumed to be dependent on the relative velocity 𝑣rel of the +surfaces in contact, +𝜇𝑐 = FD + (FS − FD)𝑒−DC∣𝑣rel∣ +where the direction and surface are left off for clarity. The OR- +THO_FRICTION option applies to contact types: +AUTOMATIC_SURFACE_TO_SUFACE, +AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE, +when they are defined by segment sets. +specification of an offset angle in degrees from the 1-2 side which +locates the 1 direction. The offset angle is input as the first +attribute of the segment in *SET_SEGMENT. The transverse +direction, 2, is in the plane of the segment and is perpendicular to +the 1 direction. + Each segment in the set +FDI_S or M +Dynamic coefficient of friction in the local n orthotropic direction. +DCn_S or M +Exponential decay coefficient for the local n direction. +VCn_S or M +Coefficient for viscous friction in the local n direction. See the +description for VC for mandatory Card 2 above. +LCn_S or M +*CONTACT_OPTION1_{OPTION2}_… +DESCRIPTION +The table ID of a two dimensional table, see *DEFINE_TABLE or +*DEFINE_TABLE_2D, giving the friction coefficient in the local n +direction as a function of the relative velocity and interface +pressure. In this case, each curve in the table definition defines +the coefficient of +interface pressure +corresponding to a particular value of the relative velocity. +friction versus +the +OACS_S or M +LCFS or M +If the default value, 0, is active, the frictional forces acting on a +node sliding on a segment are based on the local directions of the +segment. If OACS is set to unity, 1, the frictional forces acting on +a node sliding on a segment are based on the local directions of +the sliding node. No matter what the setting for OACS, the_S +coefficients are always used for slave nodes and the_M +coefficients for master nodes. +Optional load curve that gives the coefficient of friction as a +function of the direction of relative motion, as measured in +degrees from the first orthotropic direction. If this load curve is +specified, the other parameters (FS, FD, DC, VC, LC) are ignored. +This is currently only supported in the MPP version. +LCPS or M +Optional load curve that gives a scale factor for the friction +coefficient as a function of interface pressure. This is only used if +LCFS (or M) is defined. +Optional Card A: +Reminder: If Card 4 is required, then it must go before this optional card. +(Card 4 is required for certain contact types - see earlier in this section for +the list.) +Optional Card A. + Optional +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SOFT +SOFSCL +LCIDAB MAXPAR +SBOPT +DEPTH +BSORT +FRCFRQ +Type +Default +I +0 +F +.1 +I +0 +F +F +1.025 +0. +I +2 +I +10-100 +I +1 +Remarks +type a13 + VARIABLE +DESCRIPTION +SOFT +Soft constraint option: +EQ.0: penalty formulation, +EQ.1: soft constraint formulation, +EQ.2: segment-based contact. +EQ.4: constraint approach for FORMING contact option. +EQ.6: special contact algorithm to handle sheet blank edge +(deformable) to gage pin (rigid shell) contact during +implicit gravity loading, applies to *CONTACT_FORM- +ING_NODES_TO_SURFACE only. See more details in +About SOFT = 6. +The soft constraint may be necessary if the material constants of +the elements which make up the surfaces in contact have a wide +variation in the elastic bulk moduli. In the soft constraint option, +the interface stiffness is based on the nodal mass and the global +time step size. This method of computing the interface stiffness +will typically give much higher stiffness value than would be +obtained by using the bulk modulus; therefore, this method the +preferred approach when soft foam materials interact with +metals. See the remark below for the segment-based penalty +formulation. +SOFSCL +LCIDAB +MAXPAR +*CONTACT_OPTION1_{OPTION2}_… +DESCRIPTION +Scale factor for constraint forces of soft constraint option +(default=.10). Values greater than .5 for single surface contact and +1.0 for a one-way treatment are inadmissible. +Load curve ID defining airbag thickness as a function of time for +type a13 contact (*CONTACT_AIRBAG_SINGLE_SURFACE). +Maximum parametric coordinate in segment search (values +between 1.025 and 1.20 are recommended). This variable applies +only to SMP; for MPP, see PARMAX. Larger values can increase +cost. If zero, the default is set to 1.025 for most contact options. +Other defaults are: +EQ.1.006: SPOTWELD, +EQ.1.006: TIED_SHELL_…_CONSTRAINED_OFFSET, +EQ.1.006: TIED_SHELL_…_OFFSET, +EQ.1.006: TIED_SHELL_…_:BEAM_OFFSET, +EQ.1.100: AUTOMATIC_GENERAL +This factor allows an increase in the size of the segments which +may be useful at sharp corners. For the SPOTWELD and …_ +OFFSET options larger values can sometimes lead to numerical +instabilities; however, a larger value is sometimes necessary to +ensure that all nodes of interest are tied. +SBOPT +Segment-based contact options (SOFT = 2). +EQ.0: defaults to 2. +EQ.1: pinball edge-edge contact (not recommended) +EQ.2: assume planer segments (default) +EQ.3: warped segment checking +EQ.4: sliding option +EQ.5: do options 3 and 4 +VARIABLE +DEPTH +BSORT +FRCFRQ +DESCRIPTION +Search depth in automatic contact, check for nodal penetration +through the closest contact segments. Value of 1 (one segment) is +sufficiently accurate for most crash applications and is much less +expensive. LS-DYNA for improved accuracy sets this value to 2 +(two segments), which is default when set to zero, default search +depth for *CONTACT_AUTOMATIC_GENERAL is 3. +LT.0: |DEPTH| is the load curve ID defining searching depth +versus time. (not available when SOFT = 2) +See remarks below for segment-based contact (SOFT = 2) +options controlled by DEPTH. +Number of cycles between bucket sorts. Values of 25 and 100 are +recommended for contact types 4 and 13 (SINGLE_SURFACE), +respectively. Values of 10-15 are okay for the surface to surface +and node to surface contact. If zero, LS-DYNA determines the +interval. BSORT applies only to SMP except in the case of SOFT = 2 or for Mortar contact +(option MORTAR on the CONTACT card), in which case BSORT +applies to both SMP and MPP. For Mortar contact the default is +the value associated with NSBCS on *CONTROL_CONTACT. +LT.0: |BSORT| +load curve +ID defining bucket sorting +frequency versus time. +Number of cycles between contact force updates for penalty +contact formulations. This option can provide a significant +speed-up of the contact treatment. If used, values exceeding 3 or +4 are dangerous. Considerable care must be exercised when +using this option, as this option assumes that contact does not +change FRCFRG cycles. +EQ.0: FRCFRG is set to 1 and force calculations are performed +each cycle-strongly recommended. +Nodes in NSET #21 (create +'by path' in LSPP4.0) +Sheet blank +Sheet blank +Fixed in XZ +Gage pin (PID 20) +Fixed in Z +Fixed in XZ +Gravity loading in -Y +Gage pin +Binder ring +Lower post +Figure 11-11. Illustrative/test model for SOFT = 6 (left) and initial blank +position. +General remarks: +Setting SOFT = 1 or 2 on optional contact card A will cause the contact stiffness to be +determined based on stability considerations, taking into account the time step and +nodal masses. This approach is generally more effective for contact between materials +of dissimilar stiffness or dissimilar mesh densities. +About SOFT = 2: +SOFT = 2 is for general shell and solid element contact. This option is available for +SURFACE_TO_SURFACE, ONE_WAY_SURFACE_TO_SURFACE, and SINGLE_SUR- +FACE options including AUTOMATIC, ERODING, and AIRBAG contact. When the +AUTOMATIC option is used, orientation of shell segment normals is automatic. When +the AUTOMATIC option is not used, the segment or element orientations are used as +input. The segment-based penalty formulation contact algorithm checks for segments +vs. segment penetration rather than node vs. segment. After penetrating segments are +found, an automatic judgment is made as to which is the master segment, and penalty +forces are applied normal to that segment. The user may override this automatic +judgment by using the ONE_WAY options in which case the master segment normals +are used as input by the user. All parameters on the first three cards are active except +for VC, and VSF. On optional card A, some parameters have different meanings than +they do for the default contact. +For SOFT = 2, the SBOPT parameter on optional card A controls several options. +Setting DEPTH = 1 for pinball edge-to-edge checking is not recommended and is +included only for back compatibility. For edge-to-edge checking setting DEPTH = 5 is +recommended instead . The warped segment option more accurately checks +for penetration of warped surfaces. The sliding option uses neighbor segment +information to improve sliding behavior. It is primarily useful for preventing segments +from incorrectly catching nodes on a sliding surface. +For SOFT = 2, the DEPTH parameter controls several additional options for segment +based contact. +1. DEPTH = 2 (former default; not recommended). surface penetrations +measured at nodes are checked. +2. DEPTH = 3 (current default). Surface penetration is also be measured at the +edge. This option is more accurate than DEPTH=2, and is good for a wide +variety of simulations, but does not check for edge-to-edge penetration. +3. DEPTH = 5. Both surface penetrations and edge-to-edge penetration is +checked. +4. DEPTH = 13. The penetration checking is the same as for DEPTH=3, but the +code has been tuned to better conserve energy. +5. DEPTH = 23 or 33. The penetration checking is similar to DEPTH=3, but new +methods are used to try to improve robustness. +6. DEPTH = 25 or 35. The penetration checking is similar to DEPTH=5 but use +new methods to try to improve robustness. +7. DEPTH = 45. The splitting pinball method [Belytschko and Yeh, 1993] is used. +This method is more accurate at the cost of more CPU time, and is recommend- +ed when modeling complex contacts between parts comprised of shells. It does +not apply to solid or thick shell parts but such parts can be coated with null +shells as a means of making DEPTH=45 available. +8. DEPTH = 1 or 4. The airbag contact has two additional options, DEPTH=1 and +4. DEPTH=4 activates additional airbag logic that uses neighbor segment in- +formation when judging if contact is between interior or exterior airbag surfac- +es. This option is not recommended and is maintained only for backward +compatibility. Setting DEPTH=1 suppresses all airbag logic. +For SOFT = 2 contact, only the ISYM, I2D3D, SLDTHK, and SLDSTF parameters are +active on optional card B. Also, the negative MAXPAR option is now incorporated into +the DTSTIF option on optional card C. Data that uses the negative MAXPAR option +will continue to run correctly. +Binder ring +Pin / blank edge +contact enforced +Lower post +Gage pin +Sheet blank +final position +Sheet blank +final position +Gravity loading results without using +SOFT=6; Pin/blank edge contact missed. +Gravity loading results using SOFT=6; +Pin/blank edge contact sucessful. + Figure 11-12. Final blank position without (left) and with (right) SOFT = 6. +About SOFT = 6: +SOFT = 6 contact addresses contact issues in situation where blank gage pins are +narrow or small and blank mesh are coarse (Figure 11-11 left), leading to missing +contact in some cases. This feature applies only to gravity loading of sheet blank with +non-adaptive mesh, and for use with *CONTACT_FORMING_NODES_TO_SUR- +FACE only. +set +for +included +in a node +the variable SSID +Nodes along the entire or a portion of the blank edge to be contacted with gage pins +* CON- +must be +TACT_FORMING_NODES_TO_SURFACE (Figure 11-11 left). The nodes in the node +set must be listed in a consecutive order, as defined “by path” in LSPP4.0, under Model +→ CreEnt → Cre → Set Data → *SET_NODE. No thickness exists for either blank edge or +gage pins. In addition, the variable ORIENT in *CONTROL_CONTACT must be set to +“4”. Currently this feature is available in double precision, SMP only, starting in +in +Revision 81297 and +*CONTACT_FORMING_NODES_TO_SURFACE can be input as part ID of the blank, +making it much easier to use SOFT = 6. +in Revision 110072, SSID +later releases. + Starting +in +In a partial keyword example below, node set ID 21 (SSTYP = 4) is in contact with gage +pin of part set ID 20. As shown in Figure 11-11 (left), with the boundary condition +applied, a blank with a very coarse mesh is loaded with a body force. The left notch is +anticipated to be in contact with the gage pins. The initial position (top view) of the test +model is shown in Figure 11-11 (right) and the final gravity loaded blank positions are +shown in Figure 11-12 (left) without SOFT = 6, and in Figure 11-12 (middle and right) +with SOFT = 6, respectively. It is shown that without the SOFT = 6 the contact between +the blank edge and the pin missed completely. +*CONTROL_TERMINATION +1.0 +*CONTROL_IMPLICIT_FORMING +1 +*CONTROL_IMPLICIT_GENERAL +1,0.2 +*CONTROL_IMPLICIT_NONLINEAR +$ NSLOLVR ILIMIT MAXREF DCTOL ECTOL RCTOL LSTOL + 2 1 1200 0.000 0.00 0 +$ dnorm divflag inistif + 0 2 0 1 1 +*SET_NODE_LIST +$ blank edge node set around the gage pin +21 +1341,1342,1343,1344 +*SET_PART_LIST +$ gage pin +20 +20 +*SET_PART_LIST +$ blank +13 +13 +*CONTACT_FORMING_NODES_TO_SURFACE +$ SSID MSID SSTYP MSTYP SBOXID MBOXID SPR MPR + 21 20 4 2 +$ FS FD DC V VDC PENCHK BT DT + 0.125 20. 4 +$ SFS SFM SST MST SFST SFMT FSF VSF +$ SOFT + 6 +Beginning in Revision109342, an SSTYP of 3 (a part PID, not a part set ID) can be used +for the SSID, simplifying the definition of contact interfaces for SOFT = 6. In Soft 6 +contact definition below, a blank PID of 13 is defined for the SSID using SSTYP = 3: +*CONTACT_FORMING_NODES_TO_SURFACE +$ SSID MSID SSTYP MSTYP SBOXID MBOXID SPR MPR + 13 20 3 2 +$ FS FD DC V VDC PENCHK BT DT + 0.125 20. 4 +$ SFS SFM SST MST SFST SFMT FSF VSF +$ SOFT + 6 + +Optional Card B: +Reminder: If Optional Card B is used, then Optional Card A must be defined. +(Optional Card A may be a blank line). +Optional Card B. + Optional +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PENMAX +THKOPT +SHLTHK +SNLOG +ISYM +I2D3D +SLDTHK +SLDSTF +Type +Default +F +0 +I +0 +I +0 +I +0 +I +0 +I +0 +F +0 +F +0 +Remarks + VARIABLE +PENMAX +Old +types 3, +5, 10 +Old +types 3, +5, 10 +DESCRIPTION +Maximum penetration distance for old type 3, 5, 8, 9, 10 and +Mortar contact or the segment thickness multiplied by PENMAX +defines the maximum penetration allowed (as a multiple of the +segment thickness) for contact types a 3, a 5, a10, 13, 15, and 26. +: +EQ.0.0: for old type contacts 3, 5, and 10: Use small penetration +search and value calculated from thickness and +XPENE, see *CONTROL_CONTACT. +EQ.0.0: for contact types a 3, a 5, a10, 13, and 15: Default is 0.4, +or 40 percent of the segment thickness +EQ.0.0: for contact type26 the default value is the segment +thickness multiplied by 10 +EQ.0.0: for Mortar contact the default is a characteristic size of +the element, see Theory manual +VARIABLE +DESCRIPTION +THKOPT +Thickness option for contact types 3, 5, and 10: +SHLTHK +EQ.0: default is taken from control card, *CONTROL_CON- +TACT, +EQ.1: thickness offsets are included, +EQ.2: thickness offsets are not included (old way). +Define if and only if THKOPT above equals 1. Shell thickness +considered in type surface to surface and node to surface type +contact options, where options 1 and 2 below activate the new +contact algorithms. The thickness offsets are always included in +single surface and constraint method contact types: +EQ.0: thickness is not considered, +EQ.1: thickness is considered but rigid bodies are excluded, +EQ.2: thickness is considered including rigid bodies. +SNLOG +Disable shooting node logic in thickness offset contact. With the +shooting node logic enabled, the first cycle that a slave node +penetrates a master segment, that node is moved back to the +master surface without applying any contact force. +EQ.0: logic is enabled (default), +EQ.1: logic +is +skipped +for +(sometimes +metalforming calculations or for contact involving foam +materials). +recommended +ISYM +Symmetry plane option: +EQ.0: off, +EQ.1: do not include faces with normal boundary constraints +(e.g., segments of brick elements on a symmetry plane). +This option is important to retain the correct boundary conditions +in the model with symmetry. For the ERODING contacts this +option may also be defined on card 4. +I2D3D +Segment searching option: +EQ.0: search 2D elements (shells) before 3D elements (solids, +thick shells) when locating segments. +EQ.1: search 3D (solids, thick shells) elements before 2D +elements (shells) when locating segments. +VARIABLE +SLDTHK +SLDSTF +DESCRIPTION +Optional solid element thickness. A nonzero positive value will +activate the contact thickness offsets in the contact algorithms + The contact treatment will then be +where offsets apply. +equivalent to the case where null shell elements are used to cover +the brick elements. The contact stiffness parameter below, +SLDSTF, may also be used to override the default value. This +parameter applies also to Mortar contacts, but SLDSTF is then +ignored. +Optional solid element stiffness. A nonzero positive value +overrides the bulk modulus taken from the material model +referenced by the solid element. For segment based contact +(SOFT = 2), SLDSTF replaces the stiffness used in the penalty +equation. This parameter does not apply to Mortar contacts. +*CONTACT_OPTION1_{OPTION2}_… +Reminder: If Optional Card C is used, then Optional Cards A and B must be +defined. (Optional Cards A and B may be blank lines). +Optional Card C. + Optional +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IGAP +IGNORE +DPRFAC / +MPAR1 +DTSTIF / +MPAR2 +FLANGL CID_RCF +Type +Default +I +1 +Remarks +VARIABLE +IGAP +I +0 +3 +F +0 +1 +F +0 +2 +F +0 +I +0 +DESCRIPTION +For mortar contact IGAP is used to progressively increase contact +stiffness for large penetrations, see remarks on mortar contact +below. +For other contacts it is a flag to improve implicit convergence +behavior at the expense of (1) creating some sticking if parts attempt +to separate and (2) possibly underreporting the contact force +magnitude in the output files rcforc and ncforc. (IMPLICIT +ONLY.). +LT.0: Set IGAP = 1 and set the distance for turning on the +stiffness to (IGAP/10) times the original distance. +EQ.1: Apply method to improve convergence (DEFAULT) +EQ.2: Do not apply method +GT.2: Set IGAP = 1 for first IGAP − 2 converged equilibrium +states, then set IGAP = 2 +VARIABLE +IGNORE +Ignore +options. +DESCRIPTION +initial penetrations +in +the *CONTACT_AUTOMATIC +LT.0: Applies only to the Mortar contact. When less than zero, +the behavior is the same as for |IGNORE|, but contact be- +tween segments belonging to the same part is ignored. +The main purpose of this option is to avoid spurious +contact detections that otherwise could result for compli- +cated geometries in a single surface contact, typically, +when eliminating initial penetrations by interference. See +IGNORE.EQ.3 and IGNORE.EQ.4. +EQ.0: Take the default value from the fourth card of the CON- +TROL_CONTACT input. +EQ.1: Allow initial penetrations to exist by tracking the initial +penetrations. +EQ.2: Allow initial penetrations to exist by tracking the initial +penetrations. However, penetration warning messages are +printed with the original coordinates and the recommend- +ed coordinates of each slave node given. +EQ.3: Applies only to the Mortar contact. With this option initial +penetrations are eliminated between time zero and the +time specified by MPAR1. Intended for small initial pene- +trations. See remarks on Mortar contact. +EQ.4: Applies only to the Mortar contact. With this option initial +penetrations are eliminated between time zero and the +time specified by MPAR1. In addition a maximum pene- +tration distance can be given as MPAR2, intended for large +initial penetrations. See remarks on Mortar contact. +VARIABLE +DPRFAC/ +MPAR1 +DESCRIPTION +Applies to the SOFT = 2 and Mortar contacts. +Depth of penetration reduction factor (DPRFAC) for SOFT = 2 +contact. +EQ.0.0: Initial penetrations are always ignored. +GT.0.0: Initial penetrations are penalized over time. +LE.-1.0: |DPRFAC| is the load curve ID defining DPRFAC +versus time. +For the mortar contact MPAR1 corresponds to initial contact +pressure in interfaces with initial penetrations if IGNORE = 2, for +IGNORE = 3,4 it corresponds to the time of closure of initial +penetrations. See remarks below. +DTSTIF/ +MPAR2 +Applies to the SOFT = 1 and SOFT = 2 and Mortar contacts. +Time step used in stiffness calculation for SOFT = 1 and SOFT = 2 +contact. +EQ.0.0: +Use the initial value that is used for time +integration. +GT.0.0: +Use the value specified. +∈ (−1.0, −0.01): use a moving average of the solution time step. +(SOFT = 2 only) +LE.-1.0: +|DTSTIF| is the ID of a curve that defines +DTSTIF vs. time. +For the mortar contact and IGNORE = 4, MPAR2 corresponds a +penetration depth that must be at least the penetration occurring in +the contact interface. See remarks below. +FLANGL +Angle tolerance in radians for feature lines option in smooth +contact. +EQ.0.0: No feature line is considered for surface fitting in smooth +contact. +GT.0.0: Any edge with angle between two contact segments +bigger than this angle will be treated as feature line dur- +ing surface fitting in smooth contact. +CID_RCF +Coordinate system ID to output rcforc force resultants and ncforc +data in a local system. +Remarks: +1. DPRFAC/MPAR1 is used only by segment based contact (SOFT = 2) and +Mortar Contact . By default, +SOFT = 2 contact measures the initial penetration between segment pairs that +are found to be in contact and subtracts the measured value from the total pene- +tration for as long as a pair of segments remains in contact. The penalty force is +proportional to this modified value. This approach prevents shooting nodes, +but may allow unacceptable penetration. DPRFAC can be used to decrease the +measured value over time until the full penetration is penalized. Setting DPR- +FAC = 0.01 will cause ~1% reduction in the measured value each cycle. The +maximum allowable value for DPRFAC is 0.1. A small value such as 0.001 is +recommended. DPRFAC does not apply to initial penetrations at the start of +the calculation, only those that are measured at later times. This prevents non- +physical movement and energy growth at the start of the calculation. +2. The anticipated use for the load curve option is to allow the initial penetrations +to be reduced at the end of a calculation if the final geometry is to be used for a +subsequent analysis. To achieve this, load curve should have a y-value of zero +until a time near the end of the analysis and then ramp up to a positive value +such as 0.01 near the end of the analysis. +3. DTSTIF/MPAR2 is used only by the SOFT = 1 and SOFT = 2 contact options +and the Mortar contact (for the latter, see remarks on Mortar contact). By de- +fault when the SOFT option is active, the contact uses the initial solution time +step to scale the contact stiffness. If the user sets DTSTIF to a nonzero value, the +inputted value will be used. Because the square of the time step appears in the +denominator of the stiffness calculation, a DTSTIF value larger than the initial +solution time step reduces the contact stiffness and a smaller value increases the +stiffness. This option could be used when one component of a larger model has +been analyzed independently and validated. When the component is inserted +into the larger model, the larger model may run at a smaller time step due to +higher mesh frequencies. In the full model analysis, setting DTSTIF equal to the +component analysis time step for the contact interface that treats the component +will cause consistent contact stiffness between the analyses. +The load curve option allows contact stiffness to be a function of time. This +should be done with care as energy will not be conserved. A special case of the +load curve option is when |DTSTIF| = LCTM on *CONTROL_CONTACT. +LCTM sets an upper bound on the solution time step. For |DTSTIF| = LCTM, +the contact stiffness time step value will track LCTM whenever the LCTM value +is less than the initial solution time step. If the LCTM value is greater, the initial +solution time step is used. This option could be used to stiffen the contact at the +end of an analysis. To achieve this, the LCTM curve should be defined such +that it is larger than the solution time step until near the end of the analysis. +Then the LCTM curve should ramp down below the solution time step causing +it to decrease and the contact to stiffen. A load curve value of 0.1 of the calcu- +lated solution time step will cause penetrations to reduce by about 99%. To +prevent shooting nodes, the rate at which the contact stiffness increases is au- +tomatically limited. Therefore, to achieve 99% reduction, the solution should be +run for perhaps 1000 cycles with a small time step. +For segment based contact (SOFT = 2), setting DTSTIF less than or equal to -0.01 +and greater than -1.0, causes the contact stiffness to be updated based on the +current solution time step. Varying the contact stiffness during a simulation +can cause energy growth so this option should be used with care when extra +stiffness is needed to prevent penetration and the solution time step has +dropped from the initial. Because quick changes in contact stiffness can cause +shooting nodes, using a moving average of the solution time step can prevent +this. The value of DTSTIF determines the number of terms in the moving aver- +age where n = 100 × (-DTSTIF) such that n = 1 for DTSTIF = -0.01 and n = 100 +for DTSTIF = -0.999. Setting DTSTIF = -1.0 triggers the load curve option de- +scribed in the previous paragraph, so DTSTIF cannot be smaller than -0.999 for +this option. +4. When SOFT = 2 on Optional Card A of *CONTACT, treatment of initial +penetrations is always like IGNORE = 1 in that initial penetrations are ignored +when calculating penalty forces. If SOFT = 2 and IGNORE = 2, then a report of +initial penetrations will be written to the messag file(s) in the first cycle. +Optional Card D: +Reminder: If Optional Card D is used, then Optional Cards A, B and C must be +defined. (Optional Cards A, B and C may be blank lines). +Optional Card D. + Optional +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Q2TRI +DTPCHK +SFNBR +FNLSCL DNLSCL +TCSO +TIEDID +SHLEDG +Type +Default +Remarks +I +0 +1 + VARIABLE +Q2TRI +F +0 +2 +F +0 +3 +F +0 +5 +F +0 +5 +I +0 +I +0 +4 +I +DESCRIPTION +Option to split quadrilateral contact segments into two triangles +(only available when SOFT = 2). +EQ.0: Off (default). +EQ.1: On for all slave shell segments. +EQ.2: On for all master shell segments. +EQ.3: On for all shell segments. +EQ.4: On for all shell segments of material type 34. +DTPCHK +Time interval between shell penetration reports (only available for +segment based contact) +EQ.0.0: Off (default). +GT.0.0: Check and report segment penetrations at time +intervals equal to DTPCHK +SFNBR +*CONTACT_OPTION1_{OPTION2}_… +DESCRIPTION +Scale factor for neighbor segment contact (only available for +segment based contact) +EQ.0.0: Off (default). +GT.0.0: Check neighbor segments for contact +LT.0.0: Neighbor segment checking with improved energy +balance when |SFNBR| < 1000. |SFNBR|≥1000 acti- +vates a split-pinball based neighbor contact with a pen- +alty force scale factor of |SFNBR+1000|. For example, +force scale factor used is 2 when SFNBR = -1002. +FNLSCL +Scale factor for nonlinear force scaling. +TCSO +Option to consider only contact segments (not all attached +elements) when computing the contact thickness for a node or +(for SEGMENT_TO_SEGMENT contact and shell +segment +elements only) +EQ.0: Off (default). +EQ.1: Only consider segments in the contact definition +DNLSCL +Distance for nonlinear force scaling. +TIEDID +Incremental displacement update for tied contacts. +EQ.0: Off (default). +EQ.1: On +SHLEDG +Flag for assuming edge shape for shells when measuring +penetration. This is available for segment based contact +EQ.0: default to SHLEDG on *CONTROL_CONTACT +EQ.1: Shell edges are assumed square and are flush with the +nodes +EQ.2: Shell edges are assumed round with radius equal to ½ +shell thickness +Remarks: +1. Q2TRI. Setting Q2TRI to a nonzero value causes quadrilateral shell segments to +be spilt into two triangles. The contact segments only are split. The elements +are not changed. This option is only available for segment based contact which +is activated by setting SOFT = 2. +2. DTPCHK (Penetration Check). Setting DTPCHK to a positive value causes a +penetration check to be done periodically with the interval equal to DTPCHK. +The check looks for shell segments that are penetrating the mid-plane of anoth- +er shell segment. It does not report on penetration of thickness offsets. The +penetrating pairs are reported to the messag file or files for MPP. If at least one +penetration is found, the total number of pairs is reported to the screen output. +This option is only available for segment based contact which is activated by +setting SOFT = 2. +3. SFNBR. SFNBR is a scale factor for optional neighbor segment contact +checking. This is available only in segment based (SOFT=2) contact. This is +helpful option when a mesh folds as can happen with compression folding of +an airbag. Only shell element segments are checked. Setting SFNBR to a nega- +tive value modifies the neighbor checking to improve energy balance. When +used, a value between -0.5 and -1.0 is recommended. +4. Round off in OFFSET and TIEBREAK. There have been several issues with +tied OFFSET contacts and AUTOMATIC_TIEBREAK contacts with offsets creat- +ing numerical round-off noise in stationary parts. By computing the interface +displacements incrementally rather than using total displacements, the round- +off errors that occur in single precision are eliminated. The incremental ap- +proach is available for the following contact types: +TIED_SURFACE_TO_SURFACE_OFFSET +TIED_NODES_TO_SURFACE_OFFSET +TIED_NODES_TO_SURFACE_CONSTRAINED_OFFSET +TIED_SHELL_EDGE_TO_SURFACE_OFFSET +AUTOMATIC_…_TIEBREAK +5. FNLSCL. FNLSCL = 𝑓 and DNLSCL = 𝑑 invoke alternative contact stiffness +scaling options. +When FNLSCL > 0 and DNLSCL > 0, the first option scales the stiffness by the +depth of penetration to provide smoother initial contact and a larger contact +force as the depth of penetration exceeds DNLSCL. The stiffness k is scaled by +the relation +𝑘 → 𝑘𝑓 √ +where 𝛿 is the depth of penetration, making the penalty force proportional to +the 3/2 power of the penetration depth. Adding a small amount of surface +damping (e.g., VDC = 10) is advised with this option. +When SOFT = 2 and FNLSCL < 0, DNLSCL > 0, an alternative stiffness scaling +scheme is used, +𝑘 → 𝑘 [ +0.01𝑓 𝐴𝑜 +𝑑(𝑑 − 𝛿) +] +where 𝐴0 is the overlap area of segments in contact. For 𝛿 greater than 0.9𝑑, the +stiffness is extrapolated to prevent it from going to infinity. +When SOFT = 2, FNLSCL > 0, and DNLSCL = 0, an option to scale the contact +by the overlap area is invoked. +𝑘 → 𝑘𝑓 ( +𝐴𝑜 +𝐴𝑚 + ) +where 𝐴𝑚 is the mean area of all the contact segments in the contact interface. +This third option can improve friction behavior, particularly when the FS = 2 +option is used. +Optional Card E: +Reminder: If Optional Card E is used, then Optional Cards A, B, C and D must +be defined. (Optional Cards A, B, C and D may be blank lines). +Optional Card E. + Optional +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SHAREC CPARM8 +IPBACK +SRNDE +FRICSF +ICOR +FTORQ +REGION +Type +Default +Remarks +I +0 +1 +I +0 +I +0 +2 +I +0 +3 +F +1. +5 +I +0 +I +0 +I +0 +4 + VARIABLE +DESCRIPTION +SHAREC +Shared constraint flag (only available for segment based contact) +CPARM8 +EQ.0: Segments that share constraints not checked for contact. +EQ.1: Segments that share constraints are checked for contact. +This variable is similar to CPARM8 in *CONTACT_…_MPP but +applies to SMP and not to MPP. CPARM8 for SMP only controls +treatment of spot weld beams in CONTACT_AUTOMATIC_- +GENERAL. +EQ.0: Spot weld (type 9) beams are not considered in the +contact even if included on the slave side of the contact. +EQ.2: Spot weld (type 9) beams are considered in the contact if +included on the slave side of the contact. +IPBACK +If set to a nonzero value, creates a “backup” penalty tied contact +for this interface. This option applies to constrained tied contacts +only. See Remark 2. +SRNDE +*CONTACT_OPTION1_{OPTION2}_… +DESCRIPTION +Flag for non-extended exterior shell edges. See Remark 3 below +for further information and restrictions: +EQ.0: Exterior shell edges have their usual treatment where the +contact surface extends beyond the shell edge. +EQ.1: The contact surface is rounded at exterior shell edges but +does not extend beyond the shell edges. +EQ.2: The shell edges are square. +FRICSF +Scale factor for frictional stiffness (available for SOFT = 2 only). +ICOR +FTORQ +If set to a nonzero value, VDC is the coefficient of restitution +expressed as a percentage. When SOFT = 0 or 1, this option +applies to AUTOMATIC_NODES_TO_SURFACE, AUTOMAT- +IC_SURFACE_TO_SURFACE and AUTOMATIC_SINGLE_SUR- +FACE. When SOFT = 2, it applies to all available keywords. +If set to 1, a torsional force is computed in the beam to beam +portion of contact +type AUTOMATIC_GENERAL, which +balances the torque produced due to friction. This is currently +only available in the MPP version. +REGION +The ID of a *DEFINE_REGION which will delimit the volume of +space where this contact is active. See Remark 4 below. +Remarks: +1. The SHAREC flag is a segment based contact option that allows contact +checking of segment pairs that share a multi-point constraint or rigid body. +Sharing a constraint is defined as having at least one node of each segment that +belongs to the same constraint. +2. The IPBACK flag is only applicable to constraint based tied contacts (TIED with +no options, or with CONSTRAINED_OFFSET). An identical penalty based +contact is generated with type OFFSET, except in the case of SHELL_EDGE +constrained contact which generates a BEAM_OFFSET type. The ID of the +generated interface will be set to the ID of the original interface plus 1 if that ID +is available, otherwise one more than the maximum used contact ID. For nodes +successfully tied by the constraint interface, the extra penalty tying should not +cause problems, but nodes dropped from the constraint interface due to rigid +body or other conflicting constraints will be handled by the penalty contact. In +MPP, nodes successfully tied by the constraint interface are skipped during the +penalty contact phase. +3. The SRNDE option only applies to SOFT = 0 and SOFT = 1 contacts in the MPP +version. Shell edges for these contacts are by default treated by adding cylin- +drical caps along the free edges, with the radius of the cylinder equal to half the +thickness of the segment. This has the side effect of extending the segment at +the free edges, which can cause problems. Setting SRNDE = 1 “rounds over” +the (through the thickness) corners of the element instead of extending it. The +edges of the segment are still rounded, but the overall size of the contact area is +not increased. The effect is as if the free edge of the segment was moved in +toward the segment by a distance equal to half the segment thickness, and then +the old cylindrical treatment was performed. Setting SRNDE = 2 will treat the +shell edges as square, with no extension. This variable has no effect on shell- +edge-to-shell-edge interaction in AUTOMATIC_GENERAL; for that, see CPAR- +M8 on the MPP Card. +The SRNDE = 1 option is available for the AUTOMATIC_SINGLE and AUTO- +MATIC_GENERAL contacts. The NODE_TO_SURFACE and SURFACE_TO_- +SURFACE contacts also support SRNDE = 1 if the GROUPABLE option is used. +The SRNDE = 2 option is available for all these contact types if the GROUPA- +BLE option is enabled. +4. Setting a non-zero value for REGION does not limit or in any way alter the list +of slave or master nodes or segments, and this option should not be used for +that purpose. For efficiency, the smallest possible portion of the model should +be defined as slave or master using the normal mechanisms for specifying the +slave and master surfaces. Setting a non-zero value will, however, result in +contact outside the REGION being ignored. As slave and master nodes and +segments pass into the indicated REGION, contact for them will become active. +As they pass out of the REGION, they will be skipped in the contact calculation. +This option is currently only available for the MPP version, and only for con- +tacts of type AUTOMATIC_SINGLE_SURFACE, and AUTOMATIC_*_TO_- +SURFACE. +5. The FRICSF factor is an optional factor to scale the frictional stiffness. FRICSF +is available only when SOFT = 2 on optional card A. With penalty contact, the +frictional force is a function of the stiffness, the sliding distance, and the Cou- +lomb limit. +*CONTACT_OPTION1_{OPTION2}_… +Reminder: If Optional Card F is used, then Optional Cards A, B, C, D and E +must be defined. (Optional Cards A, B, C, D and E may be blank lines). +Optional Card F. + Optional +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PSTIFF +IGNROFF +Type +Default +Remarks +I +0 +1 + VARIABLE +PSTIFF +I + 0 +DESCRIPTION +Flag to choose the method for calculating the penalty stiffness. +This is available for segment based contact +EQ.0: Use the default as defined by PSTIFF on *CONTROL_- +CONTACT. +EQ.1: Based on nodal masses +EQ.2: Based on material density and segment dimensions. +IGNROFF +Flag to ignore the thickness offset for shells in the calculation of +the shell contact penetration depth. This allows shells to be used +for meshing rigid body dies without modifying the positions of +the nodes to compensate for the shell thickness. +EQ.1: Ignore the master side thickness. +EQ.2: Ignore the slave side thickness. +EQ.3: Ignore the thickness of both sides.. +Remarks: +1. See Remark 6 on *CONTROL_CONTACT for an explanation of the PSTIFF +option. Specifying PSTIFF here will override the default value as defined by +PSTIFF on *CONTROL_CONTACT. +General Remarks: *CONTACT +1. Modeling airbag interactions with structures and occupants using the actual +fabric thickness, which is approximate 0.30 mm, may result in a contact break- +down that leads to inconsistent occupant behavior between different machines. +Based on our experience, using a two-way automatic type contact definition, +i.e., AUTOMATIC_SURFACE_TO_SURFACE, between any airbag to struc- +ture/occupant interaction and setting the airbag fabric contact thickness to at +least 10 times the actual fabric thickness has helped improved contact behavior +and eliminates the machine inconsistencies. Due to a large stiffness difference +between the airbag and the interacting materials, the soft constraint option +(SOFT = 1) or the segment based option (SOFT = 2) is recommended. It must be +noted that with the above contact definition, only the airbag materials should +be included in any *AIRBAG_SINGLE_SURFACE definitions to avoid duplicate +contact treatment that can lead to numerical instabilities. +2. The following contact definitions are based on constraint equations and will not +work with rigid bodies: +TIED_NODES_TO_SURFACE +TIED_NODES_TO_SURFACE_CONSTRAINED_OFFSET +TIED_SURFACE_TO_SURFACE +TIED_SURFACE_TO_SURFACE_CONSTRAINED_OFFSET +TIED_SHELL_EDGE_TO_SURFACE +TIED_SHELL_EDGE_TO_SURFACE_CONSTRAINED_OFFSET +TIED_SHELL_EDGE_TO_SOLID +SPOTWELD +SPOTWELD_WITH_TORSION +However, SPOTWELD_WITH_TORSION_PENALTY does work with rigid +bodies and tied interfaces with the offset option can be used with rigid bodies, +i.e., +TIED_NODES_TO_SURFACE_OFFSET +TIED_SHELL_EDGE_TO_SURFACE_OFFSET +TIED_SHELL_EDGE_TO_SURFACE_BEAM_OFFSET +TIED_SURFACE_TO_SURFACE_OFFSET +Also, it may sometimes be advantageous to use the CONSTRAINED_EXTRA_- +NODE_OPTION instead for tying deformable nodes to rigid bodies since in this +latter case the tied nodes may be an arbitrary distance away from the rigid +body. +Tying will only work if the surfaces are near each other. The criteria used to +determine whether a slave node is tied down is that it must be “close”. For +shell elements “close” is defined as distance, 𝛿, less than: +𝛿1 = 0.60 × (thickness of slave node + thickness of master segment) +𝛿2 = 0.05 × min(master segment diagonals) +𝛿 = max(𝛿1, 𝛿2) +If a node is further away it will not be tied and a warning message will be +printed. For solid elements the slave node thickness is zero and the segment +thickness is the element volume divided by the segment area; otherwise, the +same procedure is used. +If there is a large difference in element areas between the master and slave side, +the distance, 𝛿2, may be too large and may cause the unexpected projection of +nodes that should not be tied. This can occur during calculation when adaptive +remeshing is used. To avoid this difficulty the slave and master thickness can +be specified as negative values on Card 3 in which case +𝛿 = abs(𝛿1) +3. The contact algorithm for tying spot welds with torsion, SPOTWELD_WITH_- +TORSION, must be used with care. Parts that are tied by this option should be +subjected to stiffness proportional damping of approximately ten percent, i.e., +input a coefficient of 0.10. This can be defined for each part on the *DAMP- +ING_PART_STIFFNESS input. Stability problems may arise with this option if +damping is not used. This comment applies also to the PENALTY keyword +option. +4. These contact definitions must be used with care. The surface and the nodes +which are constrained to a surface are not allowed to be used in any other +CONSTRAINT_… contact definition: +CONSTRAINT_NODES_TO_SURFACE +CONSTRAINT_SURFACE_TO_SURFACE +If, however, contact has to be defined from both sides as in sheet metal forming, +one of these contact definitions can be a CONSTRAINT type; the other one +could be a standard penalty type such as SURFACE_TO_SURFACE or +NODES_TO_SURFACE. +5. These contact definitions require thickness to be taken into account for rigid +bodies modeled with shell elements. Therefore, care should be taken to ensure +that realistic thicknesses are specified for the rigid body shells. +AIRBAG_SINGLE_SURFACE +AUTOMATIC_GENERAL +AUTOMATIC_GENERAL_INTERIOR +AUTOMATIC_NODES_TO_SURFACE +AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE +AUTOMATIC_SINGLE_SURFACE +AUTOMATIC_SURFACE_TO_SURFACE +SINGLE_SURFACE +A thickness that is too small may result in loss of contact and an unrealistically +large thickness may result in a degradation in speed during the bucket sorts as +well as nonphysical behavior. The SHLTHK option on the *CONTROL_CON- +TACT card is ignored for these contact types. +6. Two methods are used in LS-DYNA for projecting the contact surface to +account for shell thicknesses. The choice of methods can influence the accuracy +and cost of the calculation. Segment based projection is used in contact types: + +AIRBAG_SINGLE_SURFACE +AUTOMATIC_GENERAL +AUTOMATIC_NODES_TO_SURFACE +AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE +AUTOMATIC_SINGLE_SURFACE +AUTOMATIC_SURFACE_TO_SURFACE +Nodal normal projection +Segment based projection +Figure 11-13. Nodal normal and segment based projection is used in the +contact options +FORMING_NODES_TO_SURFACE +FORMING_ONE_WAY_SURFACE_TO_SURFACE +FORMING_SURFACE_TO_SURFACE +The remaining contact types use nodal normal projections if projections are +used. The main advantage of nodal projections is that a continuous contact +surface is obtained which is much more accurate in applications such as metal +forming. The disadvantages of nodal projections are the higher costs due to the +nodal normal calculations, difficulties in treating T-intersections and other +geometric complications, and the need for consistent orientation of contact +surface segments. The contact type +SINGLE_SURFACE +uses nodal normal projections and consequently is slower than the alternatives. +7. These contact algorithms allow the total contact forces applied by all contacts to +be picked up. +FORCE_TRANSDUCER_PENALTY +FORCE_TRANSDUCER_CONSTRAINT +8. This contact does not apply any force to the model and will have no effect on +the solution. Only the slave set and slave set type need be defined for this con- +tact type. Generally, only the first three cards are defined. The force transducer +option, PENALTY, works with penalty type contact algorithms only, i.e., it does +Contact surface augment SLDTHK +Contact surface augment (SST × SFST-T)/2 +Element thickness T +Figure 11-14. Illustration of contact surface location for automatic Mortar +contact, solids on top and shells below. +not work with the CONSTRAINT or TIED options. For these latter options, use +the CONSTRAINT option. If a transducer is used for extracting forces from +Mortar contacts, the slave and master sides must be defined through parts or +part sets, segment or node sets will not gather the correct data. +NOTE: If the interactions between two surfaces are needed, +a master surface should be defined. In this case, only +the contact forces applied between the slave and +master surfaces are kept. The master surface option +is only implemented for the PENALTY option and +works only with the AUTOMATIC contact types. +9. FORMING_… These contacts are mainly used for metal forming applications. +A connected mesh is not required for the master (tooling) side but the orienta- +tion of the mesh must be in the same direction. These contact types are based +on the AUTOMATIC type contacts and consequently the performance is better +than the original two surface contacts. +10. The mortar contact, invoked by appending the suffix MORTAR to either +FORMING_SURFACE_TO_SURFACE, +AUTOMATIC_SURFACE_TO_SUR- +FACE or AUTOMATIC_SINGLE_SURFACE is a segment to segment penalty +based contact. For two segments on each side of the contact interface that are +overlapping and penetrating, a consistent nodal force assembly taking into +account the individual shape functions of the segments is performed, see Figure +11-16 for an illustration. A TRANSDUCER_PENALTY can be used for extract- +ing forces from Mortar contacts, but the slave and master sides must then be defined +through parts or part sets. +In this respect the results with this contact may be more accurate, especially +when considering contact with elements of higher order. By appending the +suffix TIED to the CONTACT_AUTOMATIC_SURFACE_TO_SURFACE_MOR- +TAR keyword or the suffix TIEBREAK_MORTAR (only OPTION = 7 and OP- +TION = 9 supported) to the CONTACT_AUTOMATIC_SURFACE_TO_SUR- +FACE keyword, this is treated as a tied contact interface with optional failure in +the latter case. This contact is intended for implicit analysis in particular but is +nevertheless supported for explicit analysis as well. For explicit analysis, the +bucket sort frequency is 100 if not specified. +The FORMING mortar contact, in contrast to other forming contacts, does not +assume a rigid master side, but if this side consists of shell elements the normal +should be oriented towards the slave side. Furthermore, no shell thickness is +taken into account on the master side. The slave side is assumed to be a de- +formable shell part, and the orientation of the elements does not matter. How- +ever, each FORMING contact definition should be such that contact occurs with +ONE deformable slave side only, which obviously leads to multiple contact +definitions if two-sided contact is presumed. The AUTOMATIC contact is +supported for solids, shells and beams, and here the thicknesses are taken into +account both for rigid and deformable parts. Flat edge contact is supported for +shell elements and contact with beams occurs on the lateral surface area as well +as on the end tip. The contact assumes that the beam has a cylindrical shape +with a cross sectional area coinciding with that of the underlying beam element. +For the AUTOMATIC contact, the contact surface can be augmented with the +aid of parameters SST and SFST for shells and beams, while SLDTHK is used +for solids and thick shells. For shells/beams SST corresponds to the contact +thickness of the element (MST likewise for the master side), by default this is +the same as the element thickness. This parameter can be scaled with aid of +SFST (SFMT for the master side) to adjust the location of the contact surface, see +Figure 11-14. +For solids PENMAX can be used to determine the maximum penetration and +also determines the search depth for finding contact pairs, if set it should corre- +spond to a characteristic thickness in the model. Also, the contact surface can +be adjusted with the aid of SLDTHK if it is of importance to reduce the gap +between parts, see Figure 11-14. This may be of interest if initial gaps result in +free objects undergoing rigid body motion and thus preventing convergence in +implicit. +4 + 3.5 + 3 + 2.5 + 2 + 1.5 + 1 + 0.5 + 0 + 0 +IGAP=1 +IGAP=2 +IGAP=5 +IGAP=10 + 0.2 + 0.4 + 0.6 + 0.8 + 1 +Penetration +Figure 11-15. Mortar contact stress as function of penetration +For the TIED option, the criterion for tying two contact surfaces is by default +that the distance should be less than 0.05 × T, i.e., by default it is within 5% of +the element thickness (characteristic size for solids). In this case PENMAX can +be used to set the tying distance, i.e., if PENMAX is positive then segments are +tied if the distance is less than PENMAX. +If initial penetrations are detected (reported in the messag file) then by default +these will yield an initial contact stress corresponding to this level of penetra- +tion. IGNORE > 0 can be used to prevent unwanted effects of this. IG- +NORE = 2 behaves differently than from other contacts, for this option the +penetrations are not tracked but the contact surface is fixed at its initial location. +In addition, for IGNORE = 2, an initial contact pressure can be imposed on the +interface by setting the MPAR1 parameter to the desired contact pressure. All +this allows to properly eliminate any rigid body motion due to initial contact +gaps. +4 +Slave +1 +x3 +x2 +O +x1 +Master segment +Figure 11-16. Illustration of Mortar segment to segment contact +A third option is IGNORE = 3, for which prestress can be applied. This allows +initial penetrations to exists and they are closed during the time between zero +and the value given by MPAR1, thus working pretty similar to the INTERFER- +ENCE option with the exception that the closure is linear in time. A limitation +with IGNORE = 3 in this context is that the initial penetrations must be small +enough for the contact algorithm to detect them. +Thus, for large penetrations IGNORE = 4 is recommended (this can only be +used if the slave side consists of solid elements). This does pretty much the +same thing as IGNORE = 3, but the user may provide a penetration depth in +MPAR2. This depth must be at least as large as (and preferably in the order of) +the maximum initial penetration in the contact interface or otherwise an error +termination will be the result. The need for such a parameter is for the contact +algorithm to have a decent chance to locate the contact surface and thus esti- +mate the initial penetration. With this option the contact surfaces are pushed +back and placed in incident contact at places where initial penetrations are +present, this can be done for (more or less) arbitrary initial penetration depths. +As for IGNORE = 3, the contact surfaces will be restored linearly in the time +given by MPAR1. +A problem with mortar contacts in implicit analysis could be that contact pres- +sure is locally very high and leads to large enough penetrations to be released +in subsequent steps. Penetration information can be requested on MINFO on +*CONTROL_OUTPUT which issues a warning if there is a danger for this to +happen. To prevent contact release the user may increase IGAP which penaliz- +es large penetrations without affecting small penetration behavior and thereby +overall implicit performance. Figure 11-15 shows the contact pressure as func- +tion of penetration for the mortar contact, including the effect of increasing +IGAP. It also shows that for sufficiently large penetrations the contact is not +detected in subsequent steps which is something to avoid. +INTERFACE +TYPE ID +PENCHK +ELEMENT +TYPE +FORMULA FOR RELEASE +OF PENETRATING NODAL POINT +0 +1 +2 +1, 2, 6, 7 +3, 5, 8, 9, 10 +(without thickness) +3, 5, 10 (thickness), 17 +and 18 +a3, a5, a10, 13, 15 +4 +26 +solid +shell +solid +shell +solid +shell +solid +shell +solid +d = PENMAX if PENMAX > 0 +d = 1.e+10 if PENMAX = 0 +d = PENMAX if PENMAX > 0 +d = 1.e+10 if PENMAX = 0 +d = XPENE × thickness of solid element +d = XPENE thickness of shell element +d = 0.05 × minimum diagonal length +d = 0.05 × minimum diagonal length +d = XPENE × thickness of solid element +d = XPENE × thickness of shell element +d = PENMAX × thickness of solid element +[default: PENMAX = 0.5] +d = PENMAX × (slave thickness + master +shell +thickness) +[default: PENMAX = 0.4] +solid +d = 0.5 × thickness of solid element +shell +solid +d = 0.4 × (slave thickness + master +thickness) +d = PENMAX × thickness of solid element +[default: PENMAX = 10.0] +d = PENMAX × (slave thickness + master +shell +thickness) + [default: PENMAX = 10.] +Table 11-17. Criterion for node release for nodal points which have +penetrated too far. This criterion does not apply to SOFT = 2 contact. +Larger penalty stiffnesses are recommended for the contact interface +which allows nodes to be released. For node-to-surface type contacts (5, +5a) the element thicknesses which contain the node determines the nodal +thickness. The parameter is defined on the *CONTROL_CONTACT +input. +Mapping of *CONTACT keyword option to “contact type” in d3hsp: +Structured +Input Type ID +a 13 + 26 +i 26 +a 5 +a 5 +a 10 + 13 +a 3 +a 3 + 18 + 17 + 23 + 16 + 14 + 15 + 27 + 25 +m 5 +m 10 +m 3 + 5 + 5 + 10 + 20 +Keyword Name +AIRBAG_SINGLE_SURFACE +AUTOMATIC_GENERAL +AUTOMATIC_GENERAL_INTERIOR +AUTOMATIC_NODES_TO_SURFACE +AUTOMATIC_NODES_TO_SURFACE_TIEBREAK +AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE +AUTOMATIC_SINGLE_SURFACE +AUTOMATIC_SURFACE_TO_SURFACE +AUTOMATIC_SURFACE_TO_SURFACE_TIEBREAK +CONSTRAINT_NODES_TO_SURFACE +CONSTRAINT_SURFACE_TO_SURFACE +DRAWBEAD +ERODING_NODES_TO_SURFACE +ERODING_SURFACE_TO_SURFACE +ERODING_SINGLE_SURFACE +FORCE_TRANSDUCER_CONSTRAINT +FORCE_TRANSDUCER_PENALTY +FORMING_NODES_TO_SURFACE +FORMING_ONE_WAY_SURFACE_TO_SURFACE +FORMING_SURFACE_TO_SURFACE +NODES_TO_SURFACE +NODES_TO_SURFACE_INTERFERENCE +ONE_WAY_SURFACE_TO_SURFACE +RIGID_NODES_TO_RIGID_BODY +Structured +Input Type ID + 21 + 19 + 22 + 4 + 1 +Keyword Name +RIGID_BODY_ONE_WAY_TO_RIGID_BODY +RIGID_BODY_TWO_WAY_TO_RIGID_BODY +SINGLE_EDGE +SINGLE_SURFACE +SLIDING_ONLY +p 1 +SLIDING_ONLY_PENALTY + 3 + 3 + 8 + 9 + 6 +o 6 +c 6 + 7 +o 7 +c 7 +b 7 +s 7 + 2 +o 2 +c 2 +SURFACE_TO_SURFACE +SURFACE_TO_SURFACE_INTERFERENCE +TIEBREAK_NODES_TO_SURFACE +TIEBREAK_SURFACE_TO_SURFACE +TIED_NODES_TO_SURFACE +TIED_NODES_TO_SURFACE_OFFSET +TIED_NODES_TO_SURFACE_CONSTRAINED_OFFSET +TIED_SHELL_EDGE_TO_SURFACE or SPOTWELD +TIED_SHELL_EDGE_TO_SURFACE_OFFSET +TIED_SHELL_EDGE_TO_SURFACE_CONSTRAINED_OFFSET +or SPOTWELD_CONSTRAINED_OFFSET +TIED_SHELL_EDGE_TO_SURFACE_BEAM_OFFSET +SPOTWELD_BEAM_OFFSET +or +SPOTWELD_WITH_TORSION +TIED_SURFACE_TO_SURFACE +TIED_SURFACE_TO_SURFACE_OFFSET +TIED_SURFACE_TO_SURFACE_CONSTRAINED_OFFSET +*CONTACT_OPTION1_{OPTION2}_… +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *CONTACT_NODES_TO_SURFACE +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Make a simple contact that prevents the nodes in part 2 from +$ penetrating the segments in part 3. +$ +*CONTACT_NODES_TO_SURFACE +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ ssid msid sstyp mstyp sboxid mboxid spr mpr + 2 3 3 3 +$ +$ fs fd dc vc vdc penchk bt dt +$ +$ sfs sfm sst mst sfst sfmt fsf vsf +$ +$ sstype, mstype = 3 id's specified in ssid and msid are parts +$ ssid = 2 use slave nodes in part 2 +$ msid = 3 use master segments in part 3 +$ +$ Use defaults for all parameters. +$ +$$$$ Optional Cards A and B not specified (default values will be used). +$ +$ +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *CONTACT_SINGLE_SURFACE +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Create a single surface contact between four parts: 28, 97, 88 and 92 +$ - create a part set with set ID = 5, list the four parts +$ - in the *CONTACT_SINGLE_SURFACE definition specify: +$ sstyp = 2 which means the value for ssid is a part set +$ ssid = 5 use part set 5 for defining the contact surfaces +$ +$ Additional contact specifications described below. +$ +*CONTACT_SINGLE_SURFACE +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ ssid msid sstyp mstyp sboxid mboxid spr mpr + 5 2 +$ fs fd dc vc vdc penchk bt dt + 0.08 0.05 10 20 40.0 +$ sfs sfm sst mst sfst sfmt fsf vsf +$ +$ fs = 0.08 static coefficient of friction equals 0.08 +$ fd = 0.05 dynamic coefficient of friction equals 0.05 +$ dc = 10 exponential decay coefficient, helps specify the transition +$ from a static slide to a very dynamic slide +$ vdc = 20 viscous damping of 20% critical (damps out nodal +$ oscillations due to the contact) +$ dt = 40.0 contact will deactivate at 40 ms (assuming time unit is ms) +$ +$$$$ Optional Cards A and B not specified (default values will be used). +$ +$ +*SET_PART_LIST +$ sid + 5 +$ pid1 pid2 pid3 pid4 + 28 97 88 92 +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$$$$ *CONTACT_DRAWBEAD +$ +$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ +$ +$ Define a draw bead contact: +$ - the draw bead is to be made from the nodes specified in node set 2 +$ - the master segments are to be those found in the box defined by box 2 +$ that are in part 18 +$ - include slave and master forces in interface file (spr, mpr = 1) +$ +*CONTACT_DRAWBEAD +$ +$...>....1....>....2....>....3....>....4....>....5....>....6....>....7....>....8 +$ ssid msid sstyp mstyp sboxid mboxid spr mpr + 2 18 4 3 2 1 1 +$ +$ fs fd dc vc vdc penchk bt dt + 0.10 +$ +$ sfs sfm sst mst sfst sfmt fsf vsf +$ +$$$$ Card 4 required because it's a drawbead contact +$ +$ lcdidrf lcidnf dbdth dfscl numint + 3 0.17436 2.0 +$ +$ lcdidrf = 3 load curve 3 specifies the bending component of the +$ restraining force per unit draw bead length +$ dbdth = 0.17436 draw bead depth +$ dfscl = 2.0 scale load curve 3 (lcdidrf) by 2 +$ +$$$$ Optional Cards A and B not specified (default values will be used). +$ +*DEFINE_BOX +$ boxid xmm xmx ymn ymx zmn zmx + 2 0.000E+00 6.000E+00 6.000E+00 1.000E+02-1.000E+03 1.000E+03 +$ +*SET_NODE_LIST +$ sid da1 da2 da3 da4 + 2 +$ nid1 nid2 nid3 nid4 nid5 nid6 nid7 nid8 + 2580 2581 2582 2583 2584 2585 2586 2587 + 2588 2589 2590 +$ +*DEFINE_CURVE +$ lcid sidr scla sclo offa offo + 3 +$ a o +$ DEPTH FORC/LGTH +0.000E+00 0.000E+00 + 1.200E-01 1.300E+02 + 1.500E-01 2.000E+02 + 1.800E-01 5.000E+02 +*CONTACT +This card associates a wear model to a contact interface for post-processing wear +quantities. +This card does not affect the results of a simulation. Wear is associated to friction so the +frictional coefficient must be nonzero for the associated contact interface. This feature +calculates the wear depth, sliding distance and possibly user defined wear history +variables according to the specified model and writes it to the intfor database for post- +processing. Note that this data is not written unless the parameter NWEAR and/or +NWUSR are set on the *DATABASE_EXTENT_INTFOR card. 𝐻-adaptive remeshing is +supported with this feature. Implicit analysis is supported, for which mortar is the +preferred contact. + Card 1 +1 +2 +Variable +CID +WTYPE +Type +I +I +3 +P1 +F +4 +P2 +F +5 +P3 +F +6 +P4 +F +7 +P5 +F +8 +P6 +F +Default +none +none +none +none +none +none +none +none +User Defined Wear Parameter Cards. Define as many cards as needed to define P1 +parameters if and only if WTYPE.LT.0. + Card n +1 +Variable +W1 +2 +W2 +3 +W3 +4 +W4 +5 +W5 +6 +W6 +7 +W7 +8 +W8 +Type +F +F +F +F +F +F +F +F +Default +none +none +none +none +none +none +none +none + VARIABLE +DESCRIPTION +CID +Contact interface ID, see *CONTACT_… +VARIABLE +DESCRIPTION +WTYPE +Wear law +LT.0: User defined wear law, value specifies type used in +subroutine. +EQ.0: Archard’s wear law. +P1 +First wear parameter +WTYPE.EQ.0: Dimensionless scale factor 𝑘. If negative the +ID with +absolute value specifies a +𝑘 = 𝑘(𝑝, 𝑑 ̇) as a function of contact pressure 𝑝 ≥ 0 +and relative sliding velocity 𝑑 ̇≥ 0. +table +WTYPE.LT.0: Number of user wear parameters for this +interface. +P2 +Second wear parameter +WTYPE.EQ.0: Slave surface hardness parameter 𝐻𝑠. If negative +the absolute value specifies a curve ID with +𝐻𝑠 = 𝐻𝑠(𝑇𝑠) as function of slave node tempera- +ture 𝑇𝑠. +WTYPE.LT.0: Number of user wear history variables per +contact node, these can be output to the intfor +file, see NWUSR on *DATABASE_EXTENT_- +INTFOR. +P3 +Third wear parameter +WTYPE.EQ.0: Master surface hardness parameter 𝐻𝑚. + If +negative the absolute value specifies a curve ID +with 𝐻𝑚 = 𝐻𝑚(𝑇𝑚) as function of master node +temperature 𝑇𝑚. +WTYPE.LT.0: Not used. +P4 - P6 +Not used. +WN +Nth user defined wear parameter. +Remarks: +Archard’s wear law (WTYPE.EQ.0) states that the wear depth 𝑤 at a contact point +evolves with time as +𝑤̇ = 𝑘 +𝑝𝑑 ̇ +where 𝑘 > 0 is a dimensionless scale factor, 𝑝 ≥ 0 is the contact interface pressure, 𝑑 ̇≥ 0 +is the relative sliding velocity of the points in contact and 𝐻 > 0 is the surface hardness +(force per area). The wear depth for a node in contact is incremented in accordance +with this formula, accounting for different hardness of the slave and master side, 𝐻𝑠 +and 𝐻𝑚, respectively. By using negative numbers for wear parameters P1, P2 or P3, the +corresponding parameter is defined by a table or a curve. For P1, the value of 𝑘 is taken +from a table with contact pressure 𝑝 and sliding velocity 𝑑 ̇ as arguments, while for P2 or +P3, the corresponding hardness 𝐻 is taken from curves with the associated contact +nodal temperature 𝑇 as argument. That is, the slave side hardness will be a function of +the slave side temperature, and vice versa. +Customized wear laws may be specified as a user-defined subroutine called userwear. +This subroutine is called when WTYPE < 0. This subroutine is passed wear parameters + for this interface as well as number of wear history variables per +contact node. The wear parameters are defined on additional cards and the +history variables are updated in the user subroutine. The history variables can be +output to the intfor file, see NWUSR on *DATABASE_EXTENT_INTFOR. WTYPE may +be used to distinguish between different wear laws, and consequently any number of +different laws can be implemented within the same subroutine. For more information, +we refer to the source code which contains extensive commentaries and two sample +wear laws. +Only one wear law per contact interface can be specified. The procedure for activating +this feature involves +1. Using the present keyword to associate wear to a contact interface +2. Setting NWEAR and/or NWUSR on the *DATABASE_EXTENT_INTFOR card. +3. Having a contact interface with friction of a type that is supported.. If SOFT = 2 +on optional card A of the contact data, then any valid keyword option is sup- +ported. If SOFT = 0 or SOFT = 1, then the following list is supported. +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE +*CONTACT_FORMING_SURFACE_TO_SURFACE +*CONTACT_AUTOMATIC_SURFACE_TO_SURFACE +*CONTACT_FORMING_SURFACE_TO_SURFACE_MORTAR +*CONTACT_AUTOMATIC_SURFACE_TO_SURFACE_MORTAR +*CONTACT_AUTOMATIC_SINGLE_SURFACE_MORTAR +1. +_SMOOTH option is not supported +2. MPP “groupable” option is not supported +*CONTACT_ADD_WEAR +See also *DATABASE_EXTENT_INTFOR for general guidelines related to the intfor +database. +*CONTACT +Purpose: This feature allows for automatic move of a master surface in a contact +definition to close an unspecified gap between a slave and the master surface. The gap +may be caused as a result of an initial gravity loading on the slave part. The gap will be +closed on a specified time to save CPU time. The master surface in metal forming +application will typically be the upper cavity and the slave part will be the blank. This +feature is applicable only for sheet metal forming application. + Cards 1 +Variable +1 +ID +2 +3 +4 +5 +6 +7 +8 +CONTID +VID +LCID +ATIME +OFFSET +Type +I +I +I +Default +none +none +none +I +0 +F +F +0.0 +0.0 + VARIABLE +DESCRIPTION +ID +Move ID for this automatic move input. +CONTID +VID +LCID +GT.0: velocity controlled tool kinematics (the variable VAD = 0 +in *BOUNDARY_PRESCRIBED_MOTION_RIGID) +LT.0: displacement controlled tool kinematics (VAD = 2) +Contact ID, as in *CONTACT_FORMING_...._ID, which defines +the slave and master part set IDs. +Vector ID of a vector oriented in the direction of movement of the +master surface, as in *DEFINE_VECTOR. The origin of the vector +is unimportant since the direction cosines of the vector are +computed and used. +Load curve defining tooling kinematics, either by velocity versus +time or by displacement versus time. This load curve will be +adjusted automatically during a simulation to close the empty tool +travel. +ATIME +Activation time defining the moment the master surface (tool) to +be moved. +OFFSET +*CONTACT_AUTO_MOVE +DESCRIPTION +Time at which a master surface will move to close a gap distance, +which may happen following the move of another master surface. +This is useful in sequential multiple flanging or press hemming +simulation. Simulation time (CPU) is much faster based on the +shortened tool travel (no change to the termination time). +Example: gravity loading and closing with implicit static +Referring to the partial input deck below and Figure 11-18, a combined simulation of +gravity loading and binder closing of a fender outer is demonstrated on the +NUMISHEET 2002 benchmark. In this multi-step implicit static set up, the blank is +allocated 0.3 “time” units (3 implicit steps for DT0 = 0.1) to be loaded with gravity. At +the end of gravity loading, a gap of 12mm was created between the upper die and the +blank, Figure 11-19. The upper die is set to be moved at 0.3 “time” units, closing the +gap caused by the gravity effect on the blank (Figure 11-20 left). An intermediate +closing state is shown at t = 0.743 (Figure 11-20 right) while the final completed closing +is shown in Figure 11-21. It is noted that the upper die is controlled with displacement +(VAD = 2) in a shape of a right triangular in the displacement versus “time” space as +defined by load curve #201, and the ID in *CONTACT_AUTO_MOVE is set to “-1”. +*PARAMETER +R grvtime 0.3 +R endtime 1.0 +R diemv 145.45 +*CONTROL_TERMINATION +&endtime +*CONTROL_IMPLICIT_FORMING +2,2,100 +*CONTROL_IMPLICIT_GENERAL +$ IMFLAG DT0 + 1 0.10 +*CONTROL_ACCURACY + 1 2 +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE_ID +11 +.... +.... +.... +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*BOUNDARY_PRESCRIBED_MOTION_RIGID +$# pid dof vad lcid sf vid death birth + 2 3 2 201 -1.000000 0 0.0 0.000 +*CONTACT_AUTO_MOVE +$ ID ContID VID LCID ATIME + -1 11 89 201 &grvtime +*DEFINE_VECTOR +89,0.0,0.0,0.0,0.0,0.0,-10.0 +*DEFINE_CURVE +201 +0.0,0.0 +&grvtime,0.0 +1.0,&diemv +Similarly, “velocity” controlled tool kinematics is also enabled. In the example +keyword below, the “velocity” profile is ramped up initially and then kept constant. It +is noted that the variable VAD in *BOUNDARY is set to “0”, and ID in *CONTACT_- +AUTO_MOVE is set to positive “1” indicating it is a velocity boundary condition. +*PARAMETER +R grvtime 0.3 +R tramp 0.001 +R diemv 145.45 +R clsv 1000.0 +*PARAMETER_EXPRESSION +R tramp1 tramp+gravtime +R endtime tramp1+(abs(diemv)-0.5*clsv*tramp)/clsv +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE_ID +11 +.... +.... +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*BOUNDARY_PRESCRIBED_MOTION_RIGID +$# pid dof vad lcid sf vid death birth + 2 3 0 201 -1.000000 0 0.0 0.000 +*CONTACT_AUTO_MOVE +$ ID ContID VID LCID ATIME + 1 11 89 201 &grvtime +*DEFINE_VECTOR +89,0.0,0.0,0.0,0.0,0.0,-10.0 +*DEFINE_CURVE +201 +0.0,0.0 +0.2,0.0 +&tramp1,&clsv +&endtime,&clsv +Example: tool delay in sequential flanging process with explicit dynamic: +The following example demonstrates the use of the variable OFFSET. As shown in +Figure 11-22 (left), a total of 5 flange steels are auto-positioned initially according to the +initial blank shape. Upon closing of the pressure pad, a first set of 4 flanging steels +move to home completing the first stage of the stamping process (Figure 11-22 right). +The gap created by the completion of the first flanging process is closed automatically at +a time defined using variables ATIME/OFFSET (Figure 11-23 left). During the second +stage of the process, flanging steel &flg5pid moves to home completing the final flanging +(Figure 11-23 right). An excerpt from the input deck for this model can be found below. +This deck was created using LS-PrePost’s eZ-Setup feature (http://ftp.lstc.com/- +anonymous/outgoing/lsprepost/4.0/metalforming/), with two additional keywords +added:*CONTACT_AUTO_MOVE and *DEFINE_VECTOR. +Flanging steel #5 is set to move in a cam angle defined by vector #7 following the +completion of the flanging (straight down) process of flanging steel #2. The variables +ATIME and OFFSET in *CONTACT_AUTO_MOVE are both defined as &endtime4, +which is calculated based on the automatic positioning of tools/blank using *CON- +TROL_FORMING_AUTOPOSITION. At defined time, flanging steel #5 ‘jumps’ into +position to where it just comes into contact with the partially formed down-standing +flange, saving some CPU times (Figure 11-23 left). Flanging steel #5 continues to move +to its home position completing the simulation (Figure 11-23 right). The CPU time +savings is 27% in this case. +*KEYWORD +*PARAMETER +... +*PART + &flg5pid &flg5sec &flg5mid +... +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +$ Local coordinate system for flanging steel #5 move direction +*DEFINE_COORDINATE_SYSTEM +$# cid xo yo zo xl yl zl + &flg5cid -5.09548 27.6584 -8.98238 -5.43587 26.8608 -9.48034 +$# xp yp zp + -5.82509 27.5484 -8.30742 +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +$ Auto positioning +*CONTROL_FORMING_AUTOPOSITION_PARAMETER_SET +$ SID CID DIR MPID POSITION PREMOVE THICK PARORDER +... + &flg5sid &flg5cid 3 &blk1sid -1 &bthick flg5mv +*PART_MOVE +$ PID XMOV YMOV ZMOV CID IFSET +&flg5sid 0.0 0.0 &flg5mv&flg5cid 1 +... +*MAT_RIGID +$ MID RO E PR N COUPLE M ALIAS + &flg5mid 7.830E-09 2.070E+05 0.28 +$ CMO CON1 CON2 + -1 &flg5cid 110111 +$LCO or A1 A2 A3 V1 V2 V3 + &flg5cid +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*CONTACT_AUTO_MOVE +$ ID CONTID VID LCID ATIME OFFSET + 1 7 7 10 &endtim4 &endtim4 +*DEFINE_VECTOR +$ VID XT YT ZT XH YH ZH + 7 0.0 0.0 0.0-0.5931240 0.5930674-0.5444952 +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE_ID +$ CID + 7 +$ SSID MSID SSTYP MSTYP SBOXID MBOXID SPR MPR + &blk1sid &flg5sid 2 2 1 1 +$ FS FD DC VC VDC PENCHK BT DT +... +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +$ Tool kinematics +$ -------------------------closing +*BOUNDARY_PRESCRIBED_MOTION_RIGID_local +... + &flg5pid 3 0 4 1.0 0 &endtim4 +$ -------------------------flanging +*BOUNDARY_PRESCRIBED_MOTION_RIGID_local +... + &flg5pid 3 0 10 1.0 0 &endtim4 +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*END +*CONTACT +This feature is implemented in LS-DYNA Revision 64066 and later releases. The +variable OFFSET is in Revision 77137 and later releases. +Sheet blank +Upper die cavity +Lower binder +Lower punch +Figure 11-18. Initial parts auto-positioned at t = 0.0. +12mm gap +Gravity loaded +sheet blank +Figure 11-19. Gravity loading on blank at t = 0.2. +Figure 11-20. Upper die move down at t = 0.3 closing the gap (left); continue +closing at t = 0.743 (right). +Figure 11-21. Closing complete at t = 1.0. +Flanging Steel #2: 0 +Flanging steel #5: +&flg5pid +Time = 0 +Time = 0.00954 +ATIME, OFFSET, &endtime4 +Figure 11-22. A sequential flanging process (left); first set of flanging steels +reaching home (right). +Time = 0.018743 +Time = 0.026022 +Gap closes. This happens +in an “instant,” meaning +the time step does not +increment. +&flg5pid finish +flanging +Figure 11-23. Closing the empty travel (left); flanging steel &flg5pid +completes flanging process (right). +*CONTACT_COUPLING +Purpose: Define a coupling surface for MADYMO to couple LS-DYNA with +deformable and rigid parts within MADYMO. In this interface, MADYMO computes +the contact forces acting on the coupling surface, and LS-DYNA uses these forces in the +update of the motion of the coupling surface for the next time step. Contact coupling +can be used with other coupling options in LS-DYNA. +2 +3 +4 +5 +6 +7 +8 + Card 1 +Variable +1 +ID +Type +I +Default +required +Set Cards. Include on card for each coupled set. The next "*" card terminates this +input. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SID +STYPE +Type +I +I +Default +required +0 + VARIABLE +DESCRIPTION +SID +Set ID for coupling. See Remark 1 below. +STYPE +Set type: +EQ.0: part set +EQ.1: shell element set +EQ.2: solid element set +EQ.3: thick shell element set +*CONTACT +1. Only one coupling surface can be defined. If additional surfaces are defined, +the coupling information will be added to the first definition. +2. The units and orientation can be converted by using the CONTROL_COU- +PLING keyword. It is not necessary to use the same system of units in MADY- +MO and in LS-DYNA if unit conversion factors are defined. +*CONTACT_ENTITY +Purpose: Define a contact entity. Geometric contact entities treat the impact between a +deformable body defined as a set of slave nodes or nodes in a shell part set and a rigid +body. The shape of the rigid body is determined by attaching geometric entities. +Contact is treated between these geometric entities and the slave nodes using a penalty +formulation. The penalty stiffness is optionally maximized within the constraint of the +Courant criterion. As an alternative, a finite element mesh made with shells can be +used as geometric entity. Also, axisymmetric entities with arbitrary shape made with +multi-linear polygons are possible. The latter is particularly useful for metalforming +simulations. +WARNING: If the problem being simulated involves dynamic motion of the entity, care +should be taken to insure that the inertial properties of the entity are correct. It may be +necessary to use the *PART_INERTIA option to specify these properties. +The data set for *CONTACT_ENTITY consists of 5 cards: + Card 1 +1 +2 +3 +4 +Variable +PID +GEOTYP +SSID +SSTYP +Type +I +I +I +Default +required required required +I +0 +5 +SF +F +1. +6 +DF +F +0. +7 +CF +F +0. +8 +INTORD +I +0 + VARIABLE +PID +DESCRIPTION +Part ID of the rigid body to which the geometric entity is +attached, see *PART. +GEOTYPE = 1: Infinite Plane +GEOYPE = 2: Sphere +Z' +X' +Y' +GEOYPE = 3: Infinite Cylinder +GEOTYPE = 4: Hyperellipsoid +Figure 11-24. Contact Entities. + VARIABLE +DESCRIPTION +GEOTYP +Type of geometric entity: +EQ.1: plane, +EQ.2: sphere, +EQ.3: cylinder, +EQ.4: ellipsoid, +EQ.5: +torus, +EQ.6: CAL3D/MADYMO Plane, see Appendix I, +EQ.7: CAL3D/MADYMO Ellipsoid, see Appendix I, +EQ.8: VDA surface, see Appendix L, +EQ.9: rigid body finite element mesh (shells only), +EQ.10: finite plane, +EQ.11: load curve defining line as surface profile of axisym- +metric rigid bodies. +Y' +Z' +Z' +Y' +X' +g2 +GEOTYPE = 5: Torus +GEOTYPE = 10: Finite Plane +X' +g1 +Z' +- +axis of symmetry +Load Curve +X' +GEOTYPE = 11: Load Curve +Y' +Figure 11-25. More contact entities. + VARIABLE +DESCRIPTION +SSID +Slave set ID, see *SET_NODE_OPTION, *PART, or *SET_PART. +SSTYP +Slave set type: +EQ.0: node set, +EQ.1: part ID, +EQ.2: part set ID. +SF +DF +Penalty scale factor. Useful to scale maximized penalty. +Damping option, see description for *CONTACT_OPTION: +EQ.0: no damping, +GT.0: viscous damping in percent of critical, e.g., 20 for 20% +damping, +LT.0: DF must be a negative integer. -DF is the load curve ID +giving the damping force versus relative normal velocity +. +VARIABLE +DESCRIPTION +CF +Coulomb friction coefficient. See remark 2 below. +EQ.0: no friction +GT.0: constant friction coefficient +LT.0: CF must be a negative integer. -CF is the load curve ID +giving the friction coefficient versus time. +INTORD +Integration order (slaved materials only). This option is not +available with entity types 8 and 9 where only nodes are checked: +EQ.0: check nodes only, +EQ.1: 1 point integration over segments, +EQ.2: 2 × 2 integration, +EQ.3: 3 × 3 integration, +EQ.4: 4 × 4 integration, +EQ.5: 5 × 5 integration. +This option allows a check of the penetration of the rigid body +into the deformable (slaved) material. Then virtual nodes at the +location of the integration points are checked. +Remarks: +1. The optional load curves that are defined for damping versus relative normal +velocity and for force versus normal penetration should be defined in the posi- +tive quadrant. The sign for the damping force depends on the direction of the +relative velocity and the treatment is symmetric if the damping curve is in the +positive quadrant. If the damping force is defined in the negative and positive +quadrants, the sign of the relative velocity is used in the table look-up. +2. +If at any time the friction coefficient is >= 1.0, the force calculation is modified +to a constraint like formulation which allows no sliding. This is only recom- +mended for entities with constrained motion since the mass of the entity is +assumed to be infinite. +Variable +1 +BT +Type +F +2 +DT +F +Default +0. +1.E+20 +3 +SO +I +0 +4 +GO +I +0 +*CONTACT_ENTITY +5 +6 +7 +8 +ITHK +SPR +I +0 +I +0 + VARIABLE +DESCRIPTION +BT +DT +SO +GO +Birth time +Death time +Flag to use penalty stiffness as in surface-to-surface contact: +EQ.0: contact entity stiffness formulation, +EQ.1: surface to surface contact method, +EQ.2: normal force is computed via a constraint-like method. +The contact entity is considered to be infinitely massive, +so this is recommended only for entities with constrained +motion. +LT.0: SO must be an integer: +-SO is the load curve ID giving +the force versus the normal penetration. +Flag for automatic meshing of the contact entity for entity types 1- +5 and 10-11. GO = 1 creates null shells for visualization of the +contact entity. Note these shells have mass and will affect the +mass properties of the rigid body PID unless *PART_INERTIA is +used for the rigid body. +EQ.0: mesh is not generated, +EQ.1: mesh is generated. +ITHK +Flag for considering thickness for shell slave nodes (applies only +to entity types 1, 2, 3; SSTYP must be set to zero). +EQ.0: shell thickness is not considered, +EQ.1: shell thickness is considered, +VARIABLE +SPR + Card 3 +Variable +1 +XC +Type +F +Default +0. + Card 4 +Variable +1 +BX +Type +F +Default +0. +DESCRIPTION +Include +interface force files, valid only when SSTYP > 0: +the slave side +in *DATABASE_BINARY_INTFOR +EQ.1: slave side forces included. +4 +AX +F +0. +5 +AY +F +0. +4 +5 +6 +AZ +F +0 +6 +7 +8 +7 +8 +2 +YC +F +0. +2 +BY +F +0. +3 +ZC +F +0. +3 +BZ +F +0. + VARIABLE +DESCRIPTION +XC +YC +ZC +AX +AY +AZ +BX +BY +𝑥-center, 𝑥𝑐, see remarks below. +𝑦-center, 𝑦𝑐, see remarks below. +𝑧-center, 𝑧𝑐. See remarks below. +𝑥-direction for local axis 𝐀, 𝐴𝑥, see remarks below. +y-direction for local axis 𝐀, 𝐴𝑦, see remarks below. +z-direction for local axis 𝐀, 𝐴𝑧, see remarks below. +𝑥-direction for local axis 𝐁, Bx, see remarks below. +𝑦-direction for local axis 𝐁, 𝐵𝑦, see remarks below. +VARIABLE +DESCRIPTION +BZ +𝑧-direction for local axis 𝐁, 𝐵𝑧, see remarks below. +Remarks:: +1. The coordinates, (𝑥𝑐, 𝑦𝑐, 𝑧𝑐) are the positions of the local origin of the geometric +entity in global coordinates. The entity’s local A-axis is determined by the +vector (𝐴𝑥, 𝐴𝑦, 𝐴𝑧) and the local 𝐵-axis by the vector (𝐵𝑥, 𝐵𝑦, 𝐵𝑧). +2. Cards 3 and 4 define a local to global transformation. The geometric contact +entities are defined in a local system and transformed into the global system. +For the ellipsoid, this is necessary because it has a restricted definition for the +local position. For the plane, sphere, and cylinder, the entities can be defined in +the global system and the transformation becomes (𝑥𝑐, 𝑦𝑐, 𝑧𝑐) = (0,0,0), +(𝐴𝑥, 𝐴𝑦, 𝐴𝑧) = (1,0,0), and (𝐵𝑥, 𝐵𝑦, 𝐵𝑧) = (0,1,0). + Card 5 +1 +Variable +INOUT +Type +Default +I +0 +2 +G1 +F +0. +3 +G2 +F +0. +4 +G3 +F +0. +5 +G4 +F +0. +6 +G5 +F +0. +7 +G6 +F +0. +8 +G7 +F +0. + VARIABLE +INOUT +G1 +G2 +G3 +G4 +G5 +DESCRIPTION +In-out flag. Allows contact from the inside or the outside +(default) of the entity: +EQ.0: slave nodes exist outside of the entity, +EQ.1: slave nodes exist inside the entity. +Entity coefficient 𝑔1 (CAL3D/MADYMO plane or ellipse number) +for coupled analysis . +Entity coefficient 𝑔2, see remarks below. +Entity coefficient 𝑔3, see remarks below. +Entity coefficient 𝑔4, see remarks below. +Entity coefficient 𝑔5, see remarks below. +VARIABLE +DESCRIPTION +G6 +G7 +Entity coefficient 𝑔6, see remarks below. +Entity coefficient 𝑔7, see remarks below. +Remarks: +Figures 11-24 and 11-25 show the definitions of the geometric contact entities. The +relationships between the entity coefficients and the Figure 11-25 and 11-24 variables +are as described below. Note that (𝑃𝑥, 𝑃𝑦, 𝑃𝑧) defines a point and (𝑄𝑥, 𝑄𝑦, 𝑄𝑧) is a +direction vector. +GEOTYP = 1 +𝑔1 = 𝑃𝑥 +𝑔2 = 𝑃𝑦 +𝑔3 = 𝑃𝑧 +𝑔4 = 𝑄𝑥 +𝑔5 = 𝑄𝑦 +𝑔6 = 𝑄𝑧 +𝑔7 = 𝐿 +If automatic generation is used, a square plane of length L on each edge is generated +which represents the infinite plane. If generation is inactive, then g7 may be ignored. +GEOTYP = 2 +GEOTYP = 3 +𝑔1 = 𝑃𝑥 +𝑔2 = 𝑃𝑦 +𝑔3 = 𝑃𝑧 +𝑔1 = 𝑃𝑥 +𝑔2 = 𝑃𝑦 +𝑔3 = 𝑃𝑧 +𝑔4 = 𝑟 +𝑔4 = 𝑄𝑋 +𝑔5 = 𝑄𝑦 +𝑔6 = 𝑄𝑧 +𝑔7 = 𝑟 +If automatic generation is used, a cylinder of length √𝑄x +generated which represents the infinite cylinder. +2 + 𝑄𝑦 +2 + 𝑄z +2 and radius r is +GEOTYP = 4 +𝑔1 = 𝑃𝑥 +𝑔2 = 𝑃𝑦 +𝑔3 = 𝑃𝑧 +𝑔4 = 𝑎 +𝑔5 = 𝑏 +𝑔6 = 𝑐 +𝑔7 = 𝑛 (order of the ellipsoid) +*CONTACT_ENTITY +𝑔1 = Radius of torus +𝑔2 = 𝑟 +𝑔3 = number of elements along minor circumference +𝑔4 = number of elements along major circumference +𝑔1 = Blank thickness (option to override true thickness) +𝑔2 = Scale factor for true thickness (optional) +𝑔3 = Load curve ID defining thickness versus time. (optional) +GEOTYP = 8 +GEOTYP = 9 +𝑔1 = Shell thickness (option to override true thickness). +NOTE: The shell thickness specification is necessary if the slave surface is +generated from solid elements. +𝑔2 = Scale factor for true thickness (optional) +𝑔3 = Load curve ID defining thickness versus time. (optional) +GEOTYP = 10 +𝑔1 = Length of edge along X′ axis +𝑔2 = Length of edge along Y′ axis +GEOTYP = 11 +𝑔1 = Load curve ID defining axisymmetric surface profile about Z-axis. +Load curves defined by the keywords *DEFINE_CURVE or *DE- +FINE_CURVE_ENTITY can be used. +𝑔2 = Number of elements along circumference +EQ.0: default set to 10 +𝑔3 = Number of elements along axis +EQ.0: default set to 20 +EQ.-1: the elements generated from points on the load curve +𝑔4 = Number of sub divisions on load curve used to calculate contact +EQ.0: default set to 1000 +*CONTACT +Purpose: Define contact interaction between the segment of a GEBOD dummy and +parts or nodes of the finite element model. This implementation follows that of the +contact entity, however, it is specialized for the dummies. Forces may be output using +the *DATABASE_GCEOUT command. See *COMPONENT_GEBOD and Appendix N +for further details. +Conventional *CONTACT_OPTION treatment (surface-to-surface, nodes-to-surface, +etc.) can also be applied to the segments of a dummy. To use this approach it is first +necessary to determine part ID assignments by running the model through LS-DYNA's +initialization phase. +The following options are available and refer to the ellipsoids which comprise the +dummy. Options involving HAND are not applicable for the child dummy since its +lower arm and hand share a common ellipsoid. +LOWER_TORSO +MIDDLE_TORSO +UPPER_TORSO +NECK +HEAD +RIGHT_LOWER_ARM +LEFT_HAND +RIGHT_HAND +LEFT_UPPER_LEG +RIGHT_UPPER_LEG +LEFT_SHOULDER +LEFT_LOWER_LEG +RIGHT_SHOULDER +RIGHT_LOWER_LEG +LEFT_UPPER_ARM +RIGHT_UPPER_ARM +LEFT_LOWER_ARM +LEFT_FOOT +RIGHT_FOOT +1 +2 +3 +Variable +DID +SSID +SSTYP +Type +I +I +I +4 +SF +F +5 +DF +F +6 +CF +F +Default +required required required +1. +20. +0.5 +*CONTACT_GEBOD +7 +8 +INTORD +I +0 + VARIABLE +DESCRIPTION +DID +SSID +Dummy ID, see *COMPONENT_GEBOD_OPTION. +Slave set ID, see *SET_NODE_OPTION, *PART, or *SET_PART. +SSTYP +Slave set type: +EQ.0: node set, +EQ.1: part ID, +EQ.2: part set ID. +SF +DF +Penalty scale factor. Useful to scale maximized penalty. +Damping option, see description for *CONTACT_OPTION: +EQ.0: no damping, +GT.0: viscous damping in percent of critical, e.g., 20 for 20% +damping, +LT.0: DF must be an integer. -DF is the load curve ID giving +the damping force versus relative normal velocity . +CF +Coulomb friction coefficient . Assumed to +be constant. +VARIABLE +DESCRIPTION +INTORD +Integration order (slaved materials only). +EQ.0: check nodes only, +EQ.1: 1 point integration over segments, +EQ.2: 2 × 2 integration, +EQ.3: 3 × 3 integration, +EQ.4: 4 × 4 integration, +EQ.5: 5 × 5 integration. +This option allows a check of the penetration of the dummy +segment into the deformable (slaved) material. Then virtual +nodes at the location of the integration points are checked. +4 +5 +6 +7 +8 + Card 2 +Variable +1 +BT +Type +F +2 +DT +F +Default +0. +1.E+20 +3 +SO +I +0 + VARIABLE +DESCRIPTION +Birth time +Death time +Flag to use penalty stiffness as in surface-to-surface contact: +EQ.0: contact entity stiffness formulation, +EQ.1: surface to surface contact method, +LT.0: In this case SO must be an integer. |SO| gives the load +curve ID giving the force versus the normal penetration. +BT +DT +SO +Remarks: +1. The optional load curves that are defined for damping versus relative normal +velocity and for force versus normal penetration should be defined in the posi- +tive quadrant. The sign for the damping force depends on the direction of the +relative velocity and the treatment is symmetric if the damping curve is in the +positive quadrant. If the damping force is defined in the negative and positive +quadrants, the sign of the relative velocity is used in the table look-up. +2. +Insofar as these ellipsoidal contact surfaces are continuous and smooth it may +be necessary to specify Coulomb friction values larger than those typically used +with faceted contact surfaces. +*CONTACT_GUIDED_CABLE_{OPTION1}_{OPTION2} +Purpose: Define a sliding contact that guides 1D elements, such as springs, trusses, and +beams, along a path defined by a set of nodes. Only one 1D element can be in contact +with any given node in the node set at a given time. If for some reason, a node is in +contact with multiple 1D elements, one guided contact definition must be used for each +contact. The ordering of the nodal points and 1D elements in the input is arbitrary. +OPTION1 specifies that a part set ID is given with the single option: + +SET +If not used a part ID is assumed. +OPTION2 specifies that the first card to read defines the heading and ID number of the +contact interface and takes the single option: +ID +Title Card. Additional card for ID keyword option. +Title +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CID +Type +I +HEADING +A70 + VARIABLE +DESCRIPTION +CID +Contact interface ID. This must be a unique number. +HEADING +Interface descriptor. It is suggested that unique descriptions be +used. +Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NSID +PID/PSID +SOFT +SSFAC +FRIC +Type +I +I +Default +none +none +I +0 +F +F +1.0 +none + VARIABLE +DESCRIPTION +NSID +Node set ID that guides the 1D elements. +PID/PSID +Part ID or part set ID if SET is included in the keyword line. +SOFT +Flag for soft constraint option. Set to 1 for soft constraint. +SSFAC +Stiffness scale factor for penalty stiffness value. The default value +is unity. This applies to SOFT set to 0 and 1. +FRIC +Contact friction. +*CONTACT +Purpose: Define interior contact for solid elements. Frequently, when soft materials are +compressed under high pressure, the solid elements used to discretize these materials +may invert leading to negative volumes and error terminations. In order to keep these +elements from inverting, it is possible to consider interior contacts between layers of +interior surfaces made up of the faces of the solid elements. Since these interior surfaces +are generated automatically, the part (material) ID’s for the materials of interest are +defined here, prior to the interface definitions. +Define as many cards as necessary. Input ends at the next * card. Multiple instances of +this keyword may appear in the input. +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PSID1 +PSID2 +PSID3 +PSID4 +PSID5 +PSID6 +PSID7 +PSID8 +Type +I +I +I +I +I +I +I +I +Default +none +none +none +none +none +none +none +none + VARIABLE +DESCRIPTION +PSID* +Part set ID for which interior contact is desired. +Four attributes should be defined for each part set: +Attribute 1: +PSF, penalty scale factor (Default = 1.00). +Attribute 2: +Activation factor, Fa (Default = 0.10). When the crushing of the +element reaches Fa times the initial thickness the contact algorithm +begins to act. +Attribute 3: +ED, Optional modulus for interior contact stiffness. +Attribute 4: +TYPE, Formulation for interior contact. +EQ.1.0: Default, recommended for uniform compression +EQ.2.0: Designed to control the combined modes of shear and +compression. Works for type 1 brick formulation and +type 10 tetrahedron formulation. +Define each part set with the *SET_PART_COLUMN option to specify independent +attribute values for each part in the part set, +Remarks: +The interior penalty is determined by the formula: +𝐾 = +SLSFAC × PSF × Volume +3⁄ × E +Min. Thickness +where SLSFAC is the value specified on the *CONTROL_CONTACT card , volume is +the volume of the brick element, E is a constitutive modulus, and min. thickness is +approximately the thickness of the solid element through its thinnest dimension. If ED, +is defined above the interior penalty is then given instead by: +𝐾 = +3⁄ × ED +Volume +Min. Thickness +where the scaling factors are ignored. Generally, ED should be taken as the locking +modulus specified for the foam constitutive model. +Caution should be observed when using this option since if the time step size is too +large an instability may result. The time step size is not affected by the use of interior +contact. +*CONTACT +Purpose: Define rigid surface contact. The purpose of rigid surface contact is to model +large rigid surfaces, e.g., road surfaces, with nodal points and segments that require +little storage and are written out at the beginning of the binary databases. The rigid +surface motion, which can be optionally prescribed, is defined by a displacement vector +which is written with each output state. The nodal points defining the rigid surface +must be defined in the *NODE_RIGID_SURFACE section of this manual. These rigid +nodal points do not contribute degrees-of-freedom. + Card 1 +1 +2 +3 +4 +Variable +CID +PSID +BOXID +SSID +Type +I +I +Default +none +none + Card 2 +1 +2 +I +0 +3 +5 +FS +F +I +none +0. +6 +FD +F +0. +7 +DC +F +0. +8 +VC +F +0. +4 +5 +6 +7 +8 +Variable +LCIDX +LCIDY +LCIDZ +FSLCID +FDLCID +Type +Default +I +0 + Card 3 +1 +I +0 +2 +I +0 +3 +I +0 +4 +I +0 +5 +6 +7 +8 +Variable +SFS +STTHK +SFTHK +XPENE +BSORT +CTYPE +Type +F +F +F +F +I +Default +1.0 +0.0 +1.0 +4.0 +10 +I +0 + VARIABLE +DESCRIPTION +CID +Contact interface ID. This must be a unique number. +VARIABLE +DESCRIPTION +PSID +BOXID +SSID +FS +FD +DC +VC +LCIDX +LCIDY +Part set ID of all parts that may contact the rigid surface. See +*SET_PART. +Include only nodes of the part set that are within the specified +box, see *DEFINE_BOX, in contact. If BOXID is zero, all nodes +from the part set, PSID, will be included in the contact. +Segment set ID defining the rigid surface. See *SET_SEGMENT. +Static coefficient of friction. The frictional coefficient is assumed +to be dependent on the relative velocity 𝑣rel of the surfaces in +contact, +𝜇𝑐 = FD + (FS − FD)𝑒−DC∣𝑣rel∣. +If FSLCID is defined, see below, then FS is overwritten by the +value from the load curve. +Dynamic coefficient of friction. The frictional coefficient is +assumed to be dependent on the relative velocity 𝑣rel of the +surfaces in contact, +𝜇𝑐 = FD + (FS − FD)𝑒−DC∣𝑣rel∣. +If FDLCID is defined, see below, then FD is overwritten by the +value from the load curve. +Exponential decay coefficient. + The frictional coefficient is +assumed to be dependent on the relative velocity 𝑣rel of the +surfaces in contact +𝜇𝑐 = FD + (FS − FD)𝑒−DC∣𝑣rel∣. +Coefficient for viscous friction. This is necessary to limit the +friction force to a maximum. A limiting force is computed, +𝐹lim = VC × 𝐴cont. +𝐴cont being the area of the segment contacted by the node in +contact. The suggested value for VC is to use the yield stress in + where σo is the yield stress of the contacted +shear VC = +𝜎𝑜 +√3 +material. +Load curve ID defining x-direction motion. If zero, there is no +motion in the x-coordinate system. +Load curve ID defining y-direction motion. If zero, there is no +motion in the y-coordinate system. +VARIABLE +DESCRIPTION +Load curve ID defining z-direction motion. If zero, there is no +motion in the z-coordinate system. +Load curve ID defining the static coefficient of friction as a +function of interface pressure. This option applies to shell +segments only. +Load curve ID defining the dynamic coefficient of friction as a +function of interface pressure. This option applies to shell +segments only. +Scale factor on default slave penalty stiffness, see also *CON- +TROL_CONTACT. +Optional thickness for slave surface (overrides true thickness). +This option applies to contact with shell, solid, and beam +elements. True thickness is the element thickness of the shell +elements. Thickness offsets are not used for solid element unless +this option is specified. +Scale factor for slave surface thickness (scales true thickness). +This option applies only to contact with shell elements. True +thickness is the element thickness of the shell elements. +Contact surface maximum penetration check multiplier. If the +penetration of a node through the rigid surface exceeds the +product of XPENE and the slave node thickness, the node is set +free. +EQ.0: default is set to 4.0. +Number of cycles between bucket sorts. The default value is set +to 10 but can be much larger, e.g., 50-100, for fully connected +surfaces. +The contact formulation. The default, CTYPE = 0, is equivalent to +the ONE_WAY_SURFACE_TO_SURFACE +formulation, and +CTYPE = 1 is a penalty formulation. If the slave surface belongs +to a rigid body, CTYPE = 1 must be used. +LCIDZ +FSLCID +FDLCID +SFS +STTHK +SFTHK +XPENE +BSORT +CTYPE +Remarks: +Thickness offsets do not apply to the rigid surface. There is no orientation requirement +for the segments in the rigid surface, and the surface may be assembled from disjoint, +but contiguous, arbitrarily oriented meshes. With disjoint meshes, the global searches +must be done frequently, about every 10 cycles, to ensure a smooth movement of a +slave node between mesh patches. For fully connected meshes this frequency interval +can be safely set to 50-200 steps between searches. +The modified binary database, d3plot, contains the road surface information prior to the +state data. This information includes: +NPDS = Total number of rigid surface points in problem. +NRSC = Total number of rigid surface contact segments summed over all +definitions. +NSID = Number of rigid surface definitions. +NVELQ = Number of words at the end of each binary output state defining the +rigid surface motion. This equals 6 × NSID if any rigid surface moves or +zero if all rigid surfaces are stationary. +PIDS = An array equal in length to NPDS. This array defines the ID for each +point in the road surface. +XC = An array equal in length to 3 × NPDS. This array defines the global x, y, +and z coordinates of each point. +For each road surface define the following NSID sets of data: +ID = Rigid surface ID. +NS = Number of segments in rigid surface. +IXRS = An array equal in length to 4 × NS. This is the connectivity of the rigid +surface in the internal numbering system. +At the end of each state, 6 × NVELQ words of information are written. For each road +surface the x, y, and z displacements and velocities are written. If the road surface is +fixed, a null vector should be output. Skip this section if NVELQ = 0. LS-PrePost +currently displays rigid surfaces and animates their motion. +*CONTACT +Purpose: Define one-dimensional slide lines for rebar in concrete. + Card 1 +1 +2 +3 +4 +Variable +NSIDS +NSIDM +ERR +SIGC +Type +I +I +F +Default +none +none +0. +F +0. +5 +GB +F +0. +6 +7 +8 +SMAX +EXP +F +0. +F +0. + VARIABLE +DESCRIPTION +NSIDS +Nodal set ID for the slave nodes, see *SET_NODE. +NSIDM +Nodal set ID for the master nodes, see *SET_NODE. +ERR +SIGC +GB +External radius of rebar +Unconfined compressive strength of concrete, 𝑓𝑐 +Bond shear modulus +SMAX +Maximum shear strain +EXP +Exponent in damage curve +Remarks: +With this option the concrete is defined with solid elements and the rebar with truss +elements, each with their own unique set of nodal points. A string of spatially +consecutive nodes, called slave nodes, related to the truss elements may slide along +another string of spatially consecutive nodes, called master nodes, related to the solid +elements. The sliding commences after the rebar debonds. +The bond between the rebar and concrete is assumed to be elastic perfectly plastic. The +maximum allowable slip strain is given as: +𝑢max = SMAX × 𝑒−EXP×𝐷 +where 𝐷 is the damage parameter 𝐷𝑛+1 = 𝐷𝑛 + Δ𝑢. The shear force, acting on area 𝐴𝑆, +at time 𝑛 + 1 is given as: +𝑓𝑛+1 = min[𝑓𝑛 − GB × 𝐴𝑠 × Δ𝑢, GB × 𝐴𝑠 × 𝑢max] +*CONTACT_2D_OPTION1_{OPTION2}_{OPTION3} +Purpose: Define a 2-dimensional contact interface or slide line. This option is to be +used with 2D solid and shell elements using the plane stress, plane strain or +axisymmetric formulations, see *SECTION_SHELL and SECTION_BEAM. +All the 2D contacts are supported in SMP. Only *CONTACT_2D_AUTOMATIC_SIN- +GLE_SURFACE and *CONTACT_2D_AUTOMATIC_SURFACE_TO_SURFACE are +supported for MPP. +OPTION1 specifies the contact type. The following options activate kinematic +constraints and should be used with deformable materials only, but may be used with +rigid bodies if the rigid body is the master surface and all rigid body motions are +prescribed. Kinematic constraints are recommended for high pressure hydrodynamic +applications. +SLIDING_ONLY +TIED_SLIDING +SLIDING_VOIDS +AUTOMATIC_TIED_ONE_WAY +The following option uses both kinematic constraints and penalty constraints. +AUTOMATIC_TIED +The following options are penalty based. These methods have no rigid-material +limitations. They are recommended for lower pressure solid mechanics applications. +PENALTY_FRICTION +PENALTY +AUTOMATIC_SINGLE_SURFACE +AUTOMATIC_SINGLE_SURFACE_MORTAR +AUTOMATIC_SURFACE_TO_SURFACE +AUTOMATIC_SURFACE_TO_SURFACE_MORTAR +AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE +AUTOMATIC_SURFACE_IN_CONTINUUM +For these contact types, the Mortar contact is available only for implicit and only supported +in SMP at the moment. +The following options are used for SPH particles in contact with 2D solid elements (2D +shell elements are not supported currently) using the plane stress, plane strain or +axisymmetric formulations: +NODE_TO_SOLID +NODE_TO_SOLID_TIED +The following option is used to measure contact forces that are reported as RCFORC +output. +FORCE_TRANSDUCER +OPTION2 specifies a thermal contact and takes the single option: +THERMAL +Only the AUTOMATIC contact options: SINGLE_SURFACE, SURFACE_TO_SUR- +FACE, and ONE_WAY_SURFACE_TO_SURFACE may be used with the THERMAL +option. +OPTION3 specifies that the first card to read defines the title and ID number of contact +interface and takes the single option: +TITLE +Title Card. Additional card for the TITLE keyword potion. +Title +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CID +Type +I +NAME +A70 +The 2D contact may be divided into 3 groups, each with a unique input format. +1. The first group were adopted from LS-DYNA2D and originated in the public +domain version of DYNA2D from the Lawrence Livermore National Laborato- +ry. Contact surfaces are specified as ordered sets of nodes. These sets define +either contact surfaces or slide lines. The keyword options for the first group +are: +SLIDING_ONLY +TIED_SLIDING +SLIDING_VOIDS +PENALTY_FRICTION +PENALTY +NOTE: TIED_SLIDING, PENALTY_FRICTION and PE- +NALTY options are not recommended since there +are automatic options in the second group that are +easier to use and provide the same functionality. +2. The second group contains the automatic contacts. These contact surfaces may +be defined using part sets or unordered node sets. Segment orientations are +determined automatically. The keywords for these are: +AUTOMATIC_SINGLE_SURFACE +AUTOMATIC_SINGLE_SURFACE_MORTAR +AUTOMATIC_SURFACE_TO_SURFACE +AUTOMATIC_SURFACE_TO_SURFACE_MORTAR +AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE +AUTOMATIC_SURFACE_IN_CONTINUUM +AUTOMATIC_TIED +AUTOMATIC_TIED_ONE_WAY +FORCE_TRANSDUCER +3. The third group is used for SPH particles in contact with continuum elements: +NODE_TO_SOLID +NODE_TO_SOLID_TIED +Each of the 3 groups has a section below with a description of input and additional +remarks. +*CONTACT_2D_[SLIDING, TIED, & PENALTY]_OPTION +This section documents the *CONTACT_2D variations derived from DYNA2D: +SLIDING_ONLY +TIED_SLIDING +SLIDING_VOIDS +PENALTY_FRICTION +PENALTY. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SSID +MSID +TBIRTH +TDEATH +Type +I +I +F +F +Default +none +none +0. +1.e20 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EXT_PAS THETA1 +THETA2 +TOL_IG +PEN +TOLOFF +FRCSCL ONEWAY +Type +I +F +F +F +F +F +F +F +Default +none +none +none +0.001 +0.1 +0.025 +0.010 +0.0 +Friction Card. Additional card for the PENALTY_FRICTION keyword option. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FRIC +FRIC_L +FRIC_H +FRIC_S +Type +F +F +F +VARIABLE +SSID +DESCRIPTION +Nodal set ID for the slave nodes, see *SET_NODE. The slave +surface must be to the left of the master surface. +MSID +Nodal set ID for the master nodes, see *SET_NODE. +TBIRTH +Birth time for contact. +TDEATH +Death time for contact. +EXT_PAS +Slide line extension bypass option. +EQ.0: extensions are use +EQ.1: extensions are not used +THETA1 +Angle in degrees of slide line extension at first master node. +EQ.0: extension remains tangent to first master segment. +THETA2 +Angle in degrees of slide line extension at last master node. +EQ.0: extension remains tangent to last master segment. +TOL_IG +Tolerance for determining initial gaps. +EQ.0.0: default set to 0.001 +PEN +Scale factor or penalty. +EQ.0.0: default set to 0.10 +TOLOFF +Tolerance for stiffness insertion for implicit solution only. The +contact stiffness is inserted when a node approaches a segment a +distance equal to the segment length multiplied by TOLOFF. The +stiffness is increased as the node moves closer with the full +stiffness being used when the nodal point finally makes contact. +EQ.0.0: default set to 0.025. +FRCSCL +Scale factor for the interface friction. +EQ.0.0: default set to 0.010 +Better. This is the +extensionwhen m17 +is included. +Poor. This is the extension if m17 is +excluded from the slideline definition. +This extension may spuriously interact +with slave nodes s1 and s2. +m9 +m16 +m15 +m17 +m1 +m2 +m3 +m4 +m5 +m6m6 +s1 +s2 +s3 +s4 +s5 +s6 +s7 +s8 +s9 +s10 +s15 +s16 +s17 +s18 +s19 +s20 +s21 +s22 +s23 +m10 +m11 +m12 +m13 +s11 +s12 s13 s14 s24 +m7 +m8 +m14m14 +Slide Lines +14 +11 +12 +13 +14 +24 +m s m s m s +17 +24 +23 +22 +21 +20 +19 +18 +17 +16 +15 +14 +13 +12 +11 +19 +15 +16 +10 +11 +Master Slide Line +Slave Slide line +Slide line Extension +Master surface: nodes m1 - m17 +Slave surface: nodes s1 - s24 +Figure 11-26. Slide line Example. Note: (1) as recommend, for 90° angles each +facet is assigned a distinct slide line; (2) the master slide line is more coarsely +meshed; (3) the slave is to the left of the master (following the node ordering, +see inset table); (4) as shown for slave nodes 1 and 2 it is important the slide +line extension does not spuriously come into contact. + VARIABLE +ONEWAY +DESCRIPTION +Flag for one way treatment. If set to 1.0 the nodal points on the +slave surface are constrained to the master surface. This option is +generally recommended if the master surface is rigid. +EQ.1.0: activate one way treatment. +FRIC +Coefficient of friction +FRIC_L +Coefficient of friction at low velocity. +VARIABLE +DESCRIPTION +FRIC_H +Coefficient of friction at high velocity. +FRIC_S +Friction factor for shear. +Remarks: +The SLIDING_ONLY option is a two-surface method based on a kinematic formulation. +The two surfaces are allowed to slide arbitrarily large distances without friction, but are +not permitted to separate or interpenetrate. Surfaces should be initially in contact. This +option performs well when extremely high interface pressures are present. The more +coarsely meshed surface should be chosen as the master surface for best performance. +The TIED_SLIDING option joins two parts of a mesh with differing mesh refinement. It +is a kinematic formulation so the more coarsely meshed surface should be chosen as the +master. +The SLIDING_VOIDS option is a kinematic formulation without friction which permits +two surfaces to separate if tensile forces develop across the interface. The surfaces may +be initially in contact or initially separated. +The PENALTY_FRICTION and PENATLY options are penalty formulations so the +designation of master and slave surfaces is not important. The two bodies may be +initially separate or in contact. A rate-dependent Coulomb friction model is available +for PENALTY_FRICTION. +Consider two slide line surfaces in contact. It is necessary to designate one as a slave +surface and the other as a master surface. Nodal points defining the slave surface are +called slave nodes, and similarly, nodes defining the master surface are called master +nodes. Each slave-master surface combination is referred to as a slide line. +Many potential problems with the options can be avoided by observing the following +precautions: +• Metallic materials should contain the master surface along high explosive-metal +interfaces. +• SLIDING_ONLY type slide lines are appropriate along high explosive-metal +interfaces. The penalty formulation is not recommended along such interfaces. +• If one surface is more finely zoned, it should be used as the slave surface. If +penalty slide lines are used, PENALTY and PENALTY_FRICTION, then the +slave-master distinction is irrelevant. +• A slave node may have more than one master segment, and may be included as +a member of a master segment if a slide line intersection is defined. +• Angles in the master side of a slide line that approach 90° must be avoided. +Whenever such angles exist in a master surface, two or more slide lines should be +defined. This procedure is illustrated in Figure 11-26. An exception for the +foregoing rule arises if the surfaces are tied. In this case, only one slide line is +needed. +• Whenever two surfaces are in contact, the smaller of the two surfaces should be +used as the slave surface. For example, in modeling a missile impacting a wall, +the contact surface on the missile should be used as the slave surface. +• Care should be used when defining a master surface to prevent the extension +from interacting with the solution. In Figures 11-26 and 11-27, slide line exten- +sions are shown. +With extension +of slide lines turned +off, the slave nodes +move down the +inner walls as shown. +Master +surface +Slave +surface +With extension and proper +slide line definition, elements +behave as expected. +Slide line +extension +Extended slide lines do not +allow for penetration +Figure 11-27. With and without extension. Extensions may be turned off by +setting EXT_PAS (card 2), but, when turned off, slave nodes may “leak” out as +shown in the upper version of the figure. +*CONTACT_2D_[AUTOMATIC, & FORCE_TRANSDUCER]_OPTION +This section documents the following variations of *CONTACT_2D: +AUTOMATIC_SINGLE_SURFACE +AUTOMATIC_SINGLE_SURFACE_MORTAR +AUTOMATIC_SURFACE_TO_SURFACE +AUTOMATIC_SURFACE_TO_SURFACE_MORTAR +AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE +AUTOMATIC_SURFACE_IN_CONTINUUM +AUTOMATIC_TIED +AUTOMATIC_TIED_ONE_WAY +FORCE_TRANSDUCER + Card 1 +1 +2 +3 +4 +Variable +SIDS +SIDM +SFACT +FREQ +Type +I +I +F +I +Default +none +none +1.0 +50 +8 +5 +FS +F +0. +6 +FD +F +0. +7 +DC +F +0. +Remarks +1 + Card 2 +1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TBIRTH +TDEATH +SOS +SOM +NDS +NDM +COF +INIT +Type +F +F +F +F +Default +0. +1.e20 +1.0 +1.0 +Remarks +3 +3 +I +0 +2 +I +0 +2 +I +0 +I +0 +Automatic Thermal Card. Additional card for keywords with both the AUTOMATIC +and THERMAL options. For example, *CONTACT_2D_AUTOMATIC_..._THERMAL_ +..... + Card 3 +Variable +Type +1 +K +F +2 +RAD +F +3 +H +F +4 +5 +6 +7 +8 +LMIN +LMAX +CHLM +BC_FLAG +Default +none +none +none +none +none +1.0 +F +F +F +I +0 +Automatic Optional Card 1. Optional card for the AUTOMATIC keyword option. + Card 4 +Variable +1 +VC +2 +3 +4 +5 +6 +7 +8 +VDC +IPF +SLIDE +ISTIFF +TIEDGAP +IGAPCL +TIETYP +Type +F +F +Default +0. +10.0 +I +0 +I +0 +7 +I +0 +8 +R +9 +I +0 +I +0 +9 +Remarks + VARIABLE +SIDS +SIDM +DESCRIPTION +Set ID to define the slave surface. If SIDS > 0, a part set is +assumed, see *SET_PART. If SIDS < 0, a node set with ID equal to +the absolute value of SIDS is assumed, see *SET_NODE. +Set ID to define the master surface. If SIDM > 0, a part set is +assumed, see *SET_PART. If SIDM < 0, a node set with ID equal +to the absolute value of SIDM is assumed, see *SET_NODE. Do +not define for single surface contact. +SFACT +Scale factor for the penalty force stiffness. +FREQ +Search frequency. The number of timesteps between bucket sorts. +For implicit contact this parameter is ignored and the search +frequency is 1. +FS +FD +EQ.0: default set to 50. +Static coefficient of friction. The frictional coefficient is assumed +to be dependent on the relative velocity 𝑣rel of the surfaces in +contact according to the relation given by: +𝜇𝑐 = FD + (FS − FD)𝑒−DC∣𝑣𝑟𝑒𝑙∣. +Dynamic coefficient of friction. The frictional coefficient is +assumed to be dependent on the relative velocity 𝑣rel of the +surfaces in contact +𝜇𝑐 = FD + (FS − FD)𝑒−DC∣𝑣rel∣. +This parameter does not apply to Mortar contact. +DC +Exponential decay coefficient. + The frictional coefficient is +assumed to be dependent on the relative velocity 𝑣rel of the +surfaces in contact +𝜇𝑐 = FD + (FS − FD)𝑒−DC∣𝑣rel∣. +This parameter does not apply to Mortar contact. +TBIRTH +Birth time for contact. +TDEATH +Death time for contact. +SOS +Surface offset from midline for 2D shells of slave surface +EQ.0.0: default to 1. +GT.0.0: scale factor applied to actual thickness +LT.0.0: absolute value is used as the offset +SOM +Surface offset from midline for 2D shells of master surface +EQ.0: default to 1. +GT.0: scale factor applied to actual thickness +LT.0: absolute value is used as the offset +NDS +Normal direction flag for 2D shells of slave surface +EQ.0: Normal direction is determined automatically +EQ.1: Normal direction is in the positive direction +EQ.-1: Normal direction is in the negative direction +NDM +Normal direction flag for 2D shells of master surface +EQ.0: Normal direction is determined automatically +EQ.1: Normal direction is in the positive direction +EQ.-1: Normal direction is in the negative direction +COF +Closing/Opening flag for implicit contact +EQ.0: Recommended for most problem where gaps are only +closing. +EQ.1: Recommended when gaps are opening to avoid sticking. +This parameter does not apply to Mortar contact. +INIT +Special processing during initialization +EQ.0: No special processing. +EQ.1: Forming option. +K +RAD +Thermal conductivity (k) of fluid between the slide surfaces. If a +gap with a thickness 𝑙gap exists between the slide surfaces, then +the conductance due to thermal conductivity between the slide +surfaces is +ℎcond = +𝑙gap +Note that LS- DYNA calculates 𝑙gap based on deformation. +Radiation factor, f, between the slide surfaces. A radiant-heat- +transfer coefficient (ℎrad) is calculated . If a gap exists between the slide surfaces, then the +contact conductance is calculated by +ℎ = ℎcond + ℎrad +H +Heat transfer conductance (ℎ𝑐𝑜𝑛𝑡) for closed gaps. Use this heat +transfer conductance for gaps in the range +0 ≤ 𝑙gap ≤ 𝑙min +LMIN +LMAX +CHLM +where 𝑙min is GCRIT defined below. +Critical gap (𝑙min), use the heat transfer conductance defined +(HTC) for gap thicknesses less than this value. +No thermal contact if gap is greater than this value (𝑙max). +Is a multiplier used on the element characteristic distance for the +search routine. The characteristic length is the largest interface +surface element diagonal. +EQ.0: Default set to 1.0 +BC_FLAG +Thermal boundary condition flag +EQ.0: thermal boundary conditions are on when parts are in +contact +EQ.1: thermal boundary conditions are off when parts are in +contact +VC +Coefficient for viscous friction. This is used to limit the friction +force to a maximum. A limiting force is computed +𝐹lim = VC × 𝐴cont. +𝐴cont being the area of contacted between segments. The +suggested value for VC is to use the yield stress in shear: +VC = +𝜎𝑜 +√3 +where 𝜎𝑜 is the yield stress of the contacted material. +VDC +Viscous damping coefficient in percent of critical for explicit +contact. This parameter does not apply to Mortar contact. +IPF +Initial penetration flag for explicit contact. +EQ.0: Allow initial penetrations to remain +EQ.1: Push apart initially penetrated surfaces +SLIDE +Sliding option. +EQ.0: Off +EQ.1: On +ISTIFF +Stiffness scaling option. +EQ.0: Use default option. +EQ.1: Scale stiffness using segment masses and explicit time +step (default for explicit contact) +EQ.2: Scale stiffness using segment stiffness and dimensions +(default for implicit contact) +TIEDGAP +Search gap for tied contacts. +EQ.0: Default, use 1% of the master segment length +GT.0: Use the input value +LT.0: Use –TIEDGAP % of the master segment length. +IGAPCL +Flag to close gaps in tied contact +EQ.0: Default, allow gaps to remain +EQ.1: Move slave nodes to master segment to close gaps +TIETYP +Flag to control constraint type of tied contact +EQ.0: Default, use kinematic constraints when possible +EQ.1: Use only penalty type constraints +Remarks: +1. The SINGLE_SURFACE, SURFACE_TO_SURFACE, and ONE_WAY_SUR- +FACE_TO_SURFACE options use penalty forces to prevent penetration be- +tween 2D shell elements and external faces of 2D continuum elements. Contact +surfaces are defined using SIDS and SIDM to reference either part sets or node +sets. If part sets are used, all elements and continuum faces of the parts in the +set are included in contact. If node sets are used, elements or continuum faces +that have both nodes in the set are included in the contact surface. The SIN- +GLE_SURFACE option uses only the slave set and checks for contact between +all elements and continuum faces in the set. If SSID is blank or zero, contact +will be checked for all elements and continuum faces in the model. With the +other options, both SSID and MSID are required. +2. The FORCE_TRANSDUCER option should be used in conjunction with at least +one AUTOMATIC contact options. It does nothing to prevent penetration, but +measures the forces generated by other contact definitions. The FORCE_- +TRANSDUCER option uses only SIDS, and optionally SIDM. If only SIDS is +defined, the force transducer measures the resultant contact force on all the +elements and continuum faces in the slave surface. If both SIDS and SIDM are +defined, then the force transducer measures contact forces between the ele- +ments and continuum faces in the slave surface and master surface. The meas- +ured forces are included in the rcforc output. In the case of an axisymmetric +analysis, values output to rcforc and ncforc are in units of force per radian (this +includes both shell types 14 and 15). +3. By default, the normal direction of 2D shell elements is evaluated automatically +for SINGLE_SURFACE, SURFACE_TO_SURFACE and ONE_WAY_SUR- +FACE_TO_SURFACE contact. The user can override the automatic algorithm +using NDS or NDM and contact will occur with the positive or negative face of +the element. +4. By default, the true thickness of 2D shell elements is taken into account for the +SURFACE_TO_SURFACE, SINGLE_SURFACE, and ONE_WAY_SURFACE_- +TO_SURFACE options. The user can override the true thickness by using SOS +and SOM. If the surface offset is reduced to a small value, the automatic nor- +mal direction algorithm may fail, so it is best to specify the normal direction +using NDS or NDM. +5. For all AUTOMATIC contact options, eroding materials are treated by default. +At present, subcycling is not possible. +6. The INIT parameter activates a forming option that is intended for implicit +solutions of thin solid parts when back side segments may interfere with the +solution. It automatically removes back side segments during initialization. +Alternatively, the user can input INIT = 0, and use node set input to limit the +contact interface to just the front of a thin part. +7. For the thermal option: +ℎ = ℎcont, if the gap thickness is 0 ≤ 𝑙gap ≤ 𝑙min +ℎ = ℎcond + ℎrad, if the gap thickness is 𝑙min ≤ 𝑙gap ≤ 𝑙max +ℎ = 0, if the gap thickness is 𝑙gap > 𝑙max +8. The SLIDE parameter activates a sliding option which uses additional logic to +improve sliding when surfaces in contact have kinks or corners. This option is +off by default. +9. The ISTIFF option allows control of the equation used in calculating the penalty +stiffness. For backward compatibility, the default values are different for im- +plicit and explicit solutions. When ISTIFF = 1 is used, the explicit time step +appears in the stiffness equation regardless if the calculation is implicit or ex- +plicit. +10. The TIED_ONE_WAY contact creates two degree of freedom translational +kinematic constraints to nodes on the slave surface which are initially located +on or near master segments. The TIED option creates kinematic constraints +between slave nodes and master segments, and also creates penalty constraints +between master nodes and slave segments. With either contact option, a kine- +matic constraint may be switched to penalty if there is a conflict with another +constraint. The TIEDGAP parameter determines the maximum normal distance +from a segment to a node for a constraint to be formed. Nodes will not be +moved to eliminate an initial gap, and the initial gap will be maintained +throughout the calculation. If TIETYP = 1, then only penalty constraints will be +used. +11. Note that the SURFACE_IN_CONTINUUM option has been deprecated in +favor of the *CONSTRAINED_LAGRANGE_IN_SOLID keyword which allows +coupling between fluids and structures. However, this option is maintained to +provide backward compatibility for existing data. +For the SURFACE_IN_CONTINUUM option, penalty forces prevent the flow +of slave element material (the continuum) through the master surfaces. Flow of +the continuum tangent to the surface is permitted. Only 2D solid parts are +permitted in the slave part set. Both 2D solid and 2D shell parts are permitted +in the master part set. Flow through 2D shell elements is prevented in both +directions by default. If NDM is set to ±1, flow in the direction of the normal is +permitted. Thickness of 2D shell elements is ignored. +12. When using the SURFACE_IN_CONTINUUM option, there is no need to mesh +the continuum around the structure because contact is not with continuum +nodes but with material in the interior of the continuum elements. The algo- +rithm works well for Eulerian or ALE elements since the structure does not +interfere with remeshing. However, a structure will usually not penetrate the +surface of an ALE continuum since the nodes are Lagrangian normal to the +surface. Therefore, if using an ALE fluid, the structure should be initially im- +mersed in the fluid and remain immersed throughout the calculation. Penetrat- +ing the surface of an Eulerian continuum is not a problem. +13. The Mortar contact (MORTAR) is available for implicit calculations in SMP +(MPP not supported). The apparent behavior compared to the non-Mortar +contact is very similar, the difference lies in details concerning the constitutive +relation (contact stress vs relative motion of contact surfaces) and the kinemat- +ics (the relative motion of contact surfaces as function of nodal coordinates). +Mortar contact is designed for continuity and smoothness that is beneficial for +an implicit solution scheme, and is intended to enhance robustness in such a +context. For details regarding the 2D Mortar contact, see the LS-DYNA Theory +Manual. +*CONTACT_2D_NODE_TO_SOLID_OPTION +This section documents the following variations of *CONTACT_2D: +NODE_TO_SOLID +NODE_TO_SOLID_TIED + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SSID +MSID +TBIRTH +TDEATH +Type +I +I +F +F +Default +none +None +0. +1.e20 +3 +VC +F +4 +5 +OFFD +PEN +F +F +6 +FS +F +7 +FD +F +8 +DC +F +0.0 +0.0 +1.0/0.1 +0.0 +0.0 +0.0 + Card 2 +1 +2 +Variable +SOFT +Type +Default +I +0 + VARIABLE +SSID +DESCRIPTION +Nodal set ID or part set ID for the slave nodes, If SSID > 0, a +nodal set ID is assumed, If SSID < 0 a part set ID is assumed. +MSID +Master part set ID. MSID < 0 since only part set is allowed. +TBIRTH +Birth time for contact. +TDEATH +Death time for contact. +VARIABLE +DESCRIPTION +SOFT +Soft constraint option: +EQ.0: penalty formulation, +EQ.1: soft constraint formulation. +The soft constraint may be necessary if the material constants of +the parts in contact have a wide variation in the elastic bulk +moduli. In the soft constraint option, the interface stiffness is +based on the nodal mass and the global time step size. The soft +for axisymmetric +is also recommended +constraint option +simulations. +VC +Coefficient for viscous friction. This is used to limit the friction +force to a maximum. A limiting force is computed +𝐹lim = VC × 𝐴cont. +𝐴cont being the area of contacted between segments. The +suggested value for VC is to use the yield stress in shear: +VC = +𝜎𝑜 +√3 +where 𝜎𝑜 is the yield stress of the contacted material. +OFFD +Contact offset distance for slave nodes (SPH particles), not for tie +contact right now. Recommended to be half of the original +particle spacing in contact direction. +PEN +Scale factor for penalty. +FS +FD +EQ.0.0: default set to 1.0 for penalty formulation, or 0.1 for soft +constraint formulation. +Static coefficient of friction. The frictional coefficient is assumed +to be dependent on the relative velocity 𝑣rel of the surfaces in +contact according to the relationship given by: +𝜇𝑐 = FD + (FS − FD)𝑒−DC∣𝑣rel∣. +Dynamic coefficient of friction. The frictional coefficient is +assumed to be dependent on the relative velocity 𝑣rel of the +surfaces in contact +𝜇𝑐 = FD + (FS − FD)𝑒−DC∣𝑣rel∣. +DESCRIPTION +Exponential decay coefficient. + The frictional coefficient is +assumed to be dependent on the relative velocity vrel of the +surfaces in contact +𝜇𝑐 = FD + (FS − FD)𝑒−DC∣𝑣rel∣. + VARIABLE +DC +Remarks: +NODE_TO_SOLID contact is a penalty based contact type used only for SPH particles +with solid elements using the plane stress, plane strain or axisymmetric formulation. +NODE_TO_SOLID_TIED contact is used only for SPH particles tied with solid +elements, an offset of distance h (smooth length) is adopted for each SPH particle. +The keyword control cards are optional and can be used to change defaults activate +solution options such as mass scaling adaptive remeshing and an implicit solution +however it is advisable to define the CONTROL_TERMINATION card. The ordering +of the control cards in the input file is arbitrary. To avoid ambiguities define no +more than one control card of each type. The following control cards are organized in +alphabetical order +*CONTROL_ACCURACY +*CONTROL_ACOUSTIC +*CONTROL_ADAPSTEP +*CONTROL_ADAPTIVE +*CONTROL_ADAPTIVE_CURVE +*CONTROL_ALE +*CONTROL_BULK_VISCOSITY +*CONTROL_CHECK_SHELL +*CONTROL_COARSEN +*CONTROL_CONTACT +*CONTROL_COUPLING +*CONTROL_CPM +*CONTROL_CPU +*CONTROL_DEBUG +*CONTROL_DISCRETE_ELEMENT +*CONTROL_DYNAMIC_RELAXATION +*CONTROL_EFG +*CONTROL_ENERGY +*CONTROL_EXPLICIT_THERMAL_ALE_COUPLING +*CONTROL_EXPLICIT_THERMAL_BOUNDARY +*CONTROL_EXPLICIT_THERMAL_INITIAL +*CONTROL_EXPLICIT_THERMAL_OUTPUT +*CONTROL_EXPLICIT_THERMAL_PROPERTIES +*CONTROL_EXPLICIT_THERMAL_SOLVER +*CONTROL_EXPLOSIVE_SHADOW +*CONTROL_FORMING_AUTOCHECK +*CONTROL_FORMING_AUTONET +*CONTROL_FORMING_AUTOPOSITION_PARAMETER +*CONTROL_FORMING_BESTFIT +*CONTROL_FORMING_INITIAL_THICKNESS +*CONTROL_FORMING_MAXID +*CONTROL_FORMING_ONESTEP +*CONTROL_FORMING_OUTPUT +*CONTROL_FORMING_PARAMETER_READ +*CONTROL_FORMING_POSITION +*CONTROL_FORMING_PREBENDING +*CONTROL_FORMING_PROJECTION +*CONTROL_FORMING_REMOVE_ADAPTIVE_CONSTRAINTS +*CONTROL_FORMING_SCRAP_FALL +*CONTROL_FORMING_SHELL_TO_TSHELL +*CONTROL_FORMING_STONING +*CONTROL_FORMING_TEMPLATE +*CONTROL_FORMING_TIPPING +*CONTROL_FORMING_TOLERANC +*CONTROL_FORMING_TRAVEL +*CONTROL_FORMING_TRIMMING +*CONTROL_FORMING_UNFLANGING +*CONTROL_FORMING_USER +*CONTROL_FREQUENCY_DOMAIN +*CONTROL_HOURGLASS_{OPTION} +*CONTROL_IMPLICIT_AUTO +*CONTROL_IMPLICIT_BUCKLE +*CONTROL_IMPLICIT_CONSISTENT_MASS +*CONTROL_IMPLICIT_DYNAMICS +*CONTROL_IMPLICIT_EIGENVALUE +*CONTROL_IMPLICIT_FORMING +*CONTROL_IMPLICIT_GENERAL +*CONTROL_IMPLICIT_INERTIA_RELIEF +*CONTROL_IMPLICIT_JOINTS +*CONTROL_IMPLICIT_MODAL_DYNAMIC +*CONTROL_IMPLICIT_MODAL_DYNAMIC_DAMPING_{OPTION} +*CONTROL_IMPLICIT_MODAL_DYNAMIC_MODE_{OPTION} +*CONTROL_IMPLICIT_MODES_{OPTION} +*CONTROL_IMPLICIT_ROTATIONAL_DYNAMICS +*CONTROL_IMPLICIT_SOLUTION +*CONTROL_IMPLICIT_SOLVER +*CONTROL_IMPLICIT_STABILIZATION +*CONTROL_IMPLICIT_STATIC_CONDENSATION_{OPTION} +*CONTROL_IMPLICIT_TERMINATION +*CONTROL_MAT +*CONTROL_MPP_DECOMPOSITION_ARRANGE_PARTS_{OPTION} +*CONTROL_MPP_DECOMPOSITION_AUTOMATIC +*CONTROL_MPP_DECOMPOSITION_BAGREF +*CONTROL_MPP_DECOMPOSITION_CHECK_SPEED +*CONTROL_MPP_DECOMPOSITION_CONTACT_DISTRIBUTE +*CONTROL_MPP_DECOMPOSITION_CONTACT_ISOLATE +*CONTROL_MPP_DECOMPOSITION_DISTRIBUTE_ALE_ELEMENTS +*CONTROL_MPP_DECOMPOSITION_DISTRIBUTE_SPH_ELEMENTS +*CONTROL_MPP_DECOMPOSITION_ELCOST +*CONTROL_MPP_DECOMPOSITION_FILE +*CONTROL_MPP_DECOMPOSITION_METHOD +*CONTROL_MPP_DECOMPOSITION_NUMPROC +*CONTROL_MPP_DECOMPOSITION_OUTDECOMP +*CONTROL_MPP_DECOMPOSITION_PARTS_DISTRIBUTE +*CONTROL_MPP_DECOMPOSITION_PARTSET_DISTRIBUTE_{OPTION} +*CONTROL_MPP_DECOMPOSITION_RCBLOG +*CONTROL_MPP_DECOMPOSITION_SCALE_CONTACT_COST +*CONTROL_MPP_DECOMPOSITION_SCALE_FACTOR_SPH +*CONTROL_MPP_DECOMPOSITION_SHOW +*CONTROL_MPP_DECOMPOSITION_TRANSFORMATION +*CONTROL_MPP_IO_BINOUTONLY +*CONTROL_MPP_IO_LSTC_REDUCE +*CONTROL_MPP_IO_NOBEAMOUT +*CONTROL_MPP_IO_NOD3DUMP +*CONTROL_MPP_IO_NODUMP +*CONTROL_MPP_IO_NOFULL +*CONTROL_MPP_IO_SWAPBYTES +*CONTROL_MPP_MATERIAL_MODEL_DRIVER +*CONTROL_MPP_PFILE +*CONTROL_NONLOCAL +*CONTROL_OUTPUT +*CONTROL_PARALLEL +*CONTROL_PORE_FLUID +*CONTROL_REFINE_ALE +*CONTROL_REFINE_ALE2D +*CONTROL_REFINE_MPP_DISTRIBUTION +*CONTROL_REFINE_SHELL +*CONTROL_REFINE_SOLID +*CONTROL_REMESHING +*CONTROL_REQUIRE_REVISION +*CONTROL_RIGID +*CONTROL_SHELL +*CONTROL_SOLID +*CONTROL_SOLUTION +*CONTROL_SPH +*CONTROL_SPOTWELD_BEAM +*CONTROL_START +*CONTROL_STAGED_CONSTRUCTION +*CONTROL_STEADY_STATE_ROLLING +*CONTROL_STRUCTURED_{OPTION} +*CONTROL_TERMINATION +*CONTROL_THERMAL_EIGENVALUE +*CONTROL_THERMAL_NONLINEAR +*CONTROL_THERMAL_SOLVER +*CONTROL_THERMAL_TIMESTEP +*CONTROL_TIMESTEP +*CONTROL_UNITS +LS-DYNA’s implicit mode may be activated in two ways. Using the *CONTROL_IM- +PLICIT_GENERAL keyword, a simulation may be flagged to run entirely in implicit +mode. Alternatively, an explicit simulation may be seamlessly switched into implicit +mode at the termination time using the *INTERFACE_SPRINGBACK_SEAMLESS +keyword. The seamless switching feature is intended to simplify metal forming +springback calculations, where the forming phase can be run in explicit mode, followed +immediately by an implicit static springback simulation. In case of difficulty, restart +capability is supported. Eight keywords are available to support implicit analysis. +Default values are carefully selected to minimize input necessary for most simulations. +These are summarized below: +*CONTROL_IMPLICIT_GENERAL +Activates implicit mode, selects time step size. +*CONTROL_IMPLICIT_INERTIA_RELIEF +Allows linear analysis of models with rigid body modes. +*CONTROL_IMPLICIT_SOLVER +Selects parameters for solving system of linear equations [K]{x}={f}. +*CONTROL_IMPLICIT_SOLUTION +Selects linear or nonlinear solution method, convergence tolerances. +*CONTROL_IMPLICIT_AUTO +Activates automatic time step control. +*CONTROL_IMPLICIT_DYNAMICS +Activates and controls dynamic implicit solution using Newmark method. +*CONTROL_IMPLICIT_EIGENVALUE +Activates and controls eigenvalue analysis. +Activates and controls computation of constraint and attachment modes. +*CONTROL_IMPLICIT_STABILIZATION +Activates and controls artificial stabilization for multi-step spring back. +*CONTROL_ACCURACY +Purpose: Define control parameters that can improve the accuracy of the calculation. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +OSU +INN +PIDOSU +IACC +Type +I +I +I +I +Default +0 (off) +optional +0 (off) + VARIABLE +OSU +DESCRIPTION +Global flag for 2nd order objective stress updates . Generally, for explicit calculations only those parts +undergoing large rotations, such as rolling tires, need this option. +Objective stress updates can be activated for a subset of part IDs +by defining the part set in columns 21-30. +EQ.0: Off (default) +EQ.1: On +INN +Invariant node numbering for shell and solid elements. . +EQ.-4: On for both shell and solid elements except triangular +shells +EQ.-2: On for shell elements except triangular shells +EQ.1: Off (default for explicit) +EQ.2: On for shell and thick shell elements (default for +implicit) +EQ.3: On for solid elements +EQ.4: On for shell, thick shell, and solid elements +PIDOSU +Part set ID for objective stress updates. If this part set ID is given +only those part IDs listed will use the objective stress update; +therefore, OSU is ignored. +DESCRIPTION +Implicit accuracy +turns on some specific accuracy +considerations in implicit analysis at an extra CPU cost. See +Remark 4. +flag, +EQ.0: Off (default) +EQ.1: On + VARIABLE +IACC +Remarks: +1. Second Order Objective Stress Update. Second order objective stress +updates are occasionally necessary. Some examples include spinning bodies +such as turbine blades in a jet engine, high velocity impacts generating large +strains in a few time steps, and large time step sizes due to mass scaling in +metal forming. There is a significantly added cost which is due in part to the +added cost of the second order terms in the stress update when the Jaumann +rate is used and the need to compute the strain-displacement matrix at the mid- +point geometry. This option is available for one point brick elements, the selec- +tive-reduced integrated brick element which uses eight integration points, the +fully integrated plane strain and axisymmetric volume weighted (type 15) 2D +solid elements, the thick shell elements, and the following shell elements: Be- +lytschko-Tsay, Belytschko-Tsay with warping stiffness, Belytschko-Chiang- +Wong, S/R Hughes-Liu, and the type 16 fully integrated shell element. +2. +Invariant Node Numbering for Shell Elements. Invariant node numbering +for shell and thick shell elements affects the choice of the local element shell +coordinate system. The orientation of the default local coordinate system is +based on the shell normal vector and the direction of the 1-2 side of the element. +If the element numbering is permuted, the results will change in irregularly +shaped elements. With invariant node numbering, permuting the nodes shifts +the local system by an exact multiple of 90 degrees. In spite of its higher costs +[<5%], the invariant local system is recommended for several reasons. First, +element forces are nearly independent of node sequencing; secondly, the hour- +glass modes will not substantially affect the material directions; and, finally, +stable calculations over long time periods are achievable. The INN parameter +has no effect on thick shell form 2 which is always invariant and thick shell +from 3 which is never invariant. +3. +Invariant Node Numbering for Solid Elements. Invariant node numbering +for solid elements is available for anisotropic materials only. This option has no +effect on solid elements of isotropic material. This option is recommended +when solid elements of anisotropic material undergo significant deformation. +4. +Implicit Calculations. All other things being equal, a single time step of an +implicit analysis usually involves a larger time increment and deformation than +an explicit analysis. Many of the algorithms in LS-DYNA have been heavily +optimized for explicit analysis in ways that are inappropriate for implicit analy- +sis. While an implicit analysis, by default, invokes many measures to ensure +accuracy, certain corrections associated with unusual applications or with large +computational expense are invoked only by setting IACC = 1. A list of features +that are included with this option follows. +a) Strongly objective treatment of some tied contact +interfaces, see +*CONTACT. +b) Fully iterative treatment of some piecewise linear plasticity materials, see +*MAT_PIECEWISE_LINEAR_PLASTICITY +*MAT_MODIFIED_- +PIECEWISE_LINEAR_PLASTICITY, including smooth decay of stresses +down to zero when including failure. +and +c) Strong objective treatment of some elements in the context of large rota- +tions, applies to shell element types -16, 16 and 4, beam element types 1, 2 +and 9, and solid element types -2, -1, 1, 2 and 16. The superposed rigid +body motion is subtracted from these elements before evaluating the re- +sponse which significantly reduces the presence of spurious strains. +*CONTROL +Purpose: Define control parameters for transient acoustic solutions. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable MACDVP +Type +Default +I +0 + VARIABLE +MACDVP +Remarks: +DESCRIPTION +Calculate the nodal displacements and velocities of *MAT_- +ACOUSTIC volume elements for inclusion in d3plot and time- +history files. +EQ.0: Acoustic nodal motions will not be calculated +EQ.1: Acoustic nodal motions will be calculated +1. +*MAT_ACOUSTIC volume elements (ELFORM = 8 and ELFORM = 14) use the +displacement potential as the fundamental unknown. The infinitesimal mo- +tions of these acoustic nodes can be found from the gradient of the displace- +ment and velocity potentials. This is purely a post-processing endeavor and +has no effect on the predicted pressures and structural response. It will howev- +er roughly double the cost of the acoustic solution and for that reason is not +done by default. +2. The acoustic theory underpinning *MAT_ACOUSTIC volume elements +presumes infinitesimal motions. In the presence of larger motions the pressure +calculations will proceed regardless, but the calculation of acoustic nodal mo- +tions can then be unreliable. +*CONTROL_ADAPSTEP +Purpose: Define control parameters for contact interface force update during each +adaptive cycle. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FACTIN +DFACTR +Type +F +F +Default +1.0 +0.01 + VARIABLE +FACTIN +DESCRIPTION +Initial relaxation factor for contact force during each adaptive +remesh. To turn this option off set FACTIN = 1.0. Unless stability +problems occur in the contact, FACTIN = 1.0 is recommended +since this option can create some numerical noise in the resultant +tooling forces. A typical value for this parameter is 0.10. +DFACTR +Incremental increase of FACTIN during each time step after the +adaptive step. FACTIN is not allowed to exceed unity. A typical +value might be 0.01. +Remarks: +1. This command applies to contact with thickness offsets including contact types: +*CONTACT_FORMING_…_ +*CONTACT_NODES_TO_SURFACE_ +*CONTACT_SURFACE_TO_SURFACE +*CONTACT_ONE_WAY_SURFACE_TO_SURFACE. +*CONTROL +Purpose: Activate adaptive meshing. The parts which are adaptively meshed are +defined by ADPOPT under *PART. Note that “sandwiched” part’s adaptivity is +available when the variable IFSAND is set to “1” and applies to ADPOPT = 1 and 2 +only. Other related keywords include: *CONTROL_ADAPTIVE_CURVE, *DEFINE_- +CURVE_TRIM (with variable TCTOL), *DEFINE_BOX_ADAPTIVE (moving adaptive +box), and *DEFINE_CURVE_BOX_ADAPTIVITY. This keword is applicable to neither +hyperelastic materials nor any material model based on a Total Lagrangian formulation. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable ADPFREQ ADPTOL +ADPOPT MAXLVL +TBIRTH +TDEATH +LCADP +IOFLAG +Type +F +F +Default +none +1020 +I +1 +I +3 +F +F +0.0 +1020 +I +0 +I +0 +Remaining cards are optional.† + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ADPSIZE ADPASS +IREFLG +ADPENE +ADPTH MEMORY ORIENT MAXEL +Type +F +Default + Card 3 +1 +I +0 +2 +I +0 +3 +F +F +I +I +I +0.0 +inactive inactive +0 +inactive +4 +5 +6 +7 +8 +Variable +IADPN90 +IADPGH +NCFREQ +IADPCL +ADPCTL +CBIRTH +CDEATH +LCLVL +Type +Default +I +0 +I +0 +I +none +I +1 +F +F +F +F +none +0.0 +1020 +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CNLA +MMM2D ADPERR D3TRACE +IFSAND +Type +Default +F +0 + VARIABLE +ADPFREQ +ADPTOL +I +0 +I +0 +I +0 +I +0 +DESCRIPTION +Time interval between adaptive refinements, see Figures 12-2 and +12-1. +Adaptive error tolerance in degrees for ADPOPT set to 1 or 2 +below. If ADPOPT is set to 8, ADPTOL is the characteristic +element size. +ADPOPT +Adaptive options: +EQ.1: angle change in degrees per adaptive refinement relative +to the surrounding shells for each shell to be refined. +EQ.2: total angle change in degrees relative to the surrounding +shells for each shell to be refined. For example, if the +adptol = 5 degrees, the shell will be refined to the second +level when the total angle change reaches 5 degrees. +When the angle change is 10 degrees the shell will be +refined to the third level. +EQ.4: adapts when the shell error in the energy norm, Δ𝑒, +exceeds ADPTOL/100 times the mean energy norm +within the part, which is estimated as: +Δ𝑒 = (∫ +Ω𝑒 +2⁄ +‖Δ𝜎‖2 +𝑑Ω +) +where 𝐸 is Young's modulus. The error of the stresses +Δ𝜎 is defined as the difference between the the recovered +solution 𝜎 ⋆ and +i.e. +Δ𝜎 ≡ 𝜎 ⋆ − 𝜎 ℎ. Various recovery techniques for 𝜎 ⋆ and +error estimators for Δ𝑒 are defined by ADPERR. This +options works for shell types 2, 4, 16, 18, 20. +the numerical solution, 𝜎 ℎ +EQ.7: 3D r-adaptive remeshing for solid elements. Solid +element type 13, a tetrahedron, and 3-D EFG type 41 and +42, are used in the adaptive remeshing process. A com- +VARIABLE +DESCRIPTION +pletely new mesh is generated which is initialized from +the old mesh using a least squares approximation. The +mesh size is currently based on the minimum and maxi- +mum edge +the *CONTROL_- +REMESHING keyword input. This option remains +under development, and, we are not sure of its reliability +on complex geometries. +lengths defined on +EQ.8: 2D 𝑟-adaptive remeshing for axisymmetric and plane +strain continuum elements. A completely new mesh is +generated which is initialized from the old mesh using a +least squares approximation. The mesh size is currently +based on the value, ADPTOL, which gives the character- +istic element size. This option is based on earlier work +by Dick and Harris [1992]. If ADPTOL is negative, then +self-contacting material will not be merged together. The +self-merging is often preferred since it eliminates sharp +folds in the boundary; however, if the sharp fold is being +simulated unexpected results are generated. +Maximum number of refinement levels. Values of 1, 2, 3, 4, … +allow a maximum of 1, 4, 16, 64, … shells, respectively, to be +created for each original shell. The refinement level can be +overridden by *DEFINE_BOX_ADAPTIVE, or *DEFINE_SET_- +ADAPTIVE. +Birth time at which the adaptive remeshing begins, see Figures +12-2 and 12-1. +Death time at which the adaptive remeshing ends, see Figures +12-2 and 12-1. +Adaptive interval is changed as a function of time given by load +curve ID, LCADP. If this option is nonzero, the ADPFREQ will +be replaced by LCADP. The 𝑥-axis is time and the 𝑦-axis is the +varied adaptive time interval. +Flag to generate adaptive mesh at exit including *NODE, *ELE- +MENT_SHELL_THICKNESS, *BOUNDARY_option, and *CON- +STRAINED_ADAPTIVITY, to be saved in the file, adapt.msh. +EQ.1: generate ℎ-adapted mesh. +MAXLVL +TBIRTH +TDEATH +LCADP +IOFLAG +ADPSIZE +Minimum shell size to be adapted based on element edge length. +If undefined the edge length limit is ignored. +(cid:98)(cid:106)(cid:29)(cid:97)(cid:106)(cid:89) (cid:70)(cid:51)(cid:51)(cid:85) (cid:106)(cid:67)(cid:76)(cid:51) (cid:64)(cid:67)(cid:99)(cid:65) +(cid:106)(cid:82)(cid:97)(cid:119) (cid:67)(cid:78) (cid:47)(cid:107)(cid:84)(cid:72)(cid:81)(cid:105)(cid:89) +(cid:50)(cid:113)(cid:82)(cid:73)(cid:113)(cid:51) (cid:56)(cid:97)(cid:82)(cid:76) (cid:486) (cid:106)(cid:82) +(cid:486)(cid:3718) (cid:30) (cid:486) (cid:12) (cid:34)(cid:37)(cid:49)(cid:39)(cid:51)(cid:38)(cid:50)(cid:15) +(cid:99)(cid:51)(cid:106)(cid:45) (cid:486) (cid:30) (cid:486)(cid:3718) +(cid:106)(cid:51)(cid:97)(cid:67)(cid:76)(cid:67)(cid:78)(cid:29)(cid:106)(cid:67)(cid:82)(cid:78) +(cid:106)(cid:67)(cid:76)(cid:51) (cid:97)(cid:51)(cid:29)(cid:44)(cid:64)(cid:51)(cid:48)(cid:93) +(cid:119)(cid:51)(cid:99) +(cid:50)(cid:113)(cid:82)(cid:73)(cid:113)(cid:51) (cid:56)(cid:97)(cid:82)(cid:76) (cid:486) +(cid:106)(cid:82) (cid:486)(cid:3718) (cid:82)(cid:78) (cid:97)(cid:51)(cid:126)(cid:78)(cid:51)(cid:48) +(cid:76)(cid:51)(cid:99)(cid:64)(cid:89) +(cid:105)(cid:51)(cid:97)(cid:76)(cid:67)(cid:78)(cid:29)(cid:106)(cid:51)(cid:89) +(cid:114)(cid:97)(cid:67)(cid:106)(cid:51) (cid:106)(cid:82) +(cid:47)(cid:107)(cid:84)(cid:72)(cid:81)(cid:105)(cid:89) +(cid:78)(cid:82) +(cid:70)(cid:83)(cid:83)(cid:80)(cid:83) (cid:29) +(cid:85)(cid:80)(cid:77)(cid:70)(cid:83)(cid:66)(cid:79)(cid:68)(cid:70)(cid:93) +(cid:78)(cid:82) +(cid:96)(cid:51)(cid:126)(cid:78)(cid:51) (cid:76)(cid:51)(cid:99)(cid:64) (cid:29)(cid:106) (cid:106)(cid:67)(cid:76)(cid:51) +(cid:486) (cid:86)(cid:78)(cid:82)(cid:106) (cid:486)(cid:3718)(cid:87)(cid:89) (cid:47)(cid:82)(cid:78)(cid:533)(cid:106) (cid:99)(cid:29)(cid:113)(cid:51) +(cid:110)(cid:78)(cid:97)(cid:51)(cid:126)(cid:78)(cid:51)(cid:48) (cid:99)(cid:82)(cid:73)(cid:110)(cid:106)(cid:67)(cid:82)(cid:78)(cid:89) +(cid:119)(cid:51)(cid:99) +(cid:99)(cid:51)(cid:106)(cid:45) (cid:486) (cid:30) (cid:486)(cid:3718) +write +re(cid:1)ne +time +22 +tbirth +11 33 +ADPFREQ +end +time +Figure 12-1. Flowchart for ADPASS = 0. While this option is sometimes more +accurate, ADPASS = 1 is much less expensive and recommended when used +with ADPENE. + VARIABLE +DESCRIPTION +LT.0: absolute value defines +the minimum characteristic +element length to be adapted based on square root of the +element area, i.e., instead of comparing the shortest ele- +ment edge with ADPSIZE, it compares the square root of +the element area with |ADPSIZE| whenever ADPSIZE is +defined by a negative value. +ADPASS +One or two pass flag for ℎ-adaptivity: +EQ.0: two pass adaptivity as shown in Figure 12-2. +EQ.1: one pass adaptivity as shown in Figure 12-1. +IREFLG +Uniform refinement level. A value of 1, 2, 3 … allow 4, 16, 64 … +shells, respectively, to be created uniformly for each original shell. +If negative, |IREFLG| is taken as a load curve ID. With the curve +time +tbirth +(cid:98)(cid:106)(cid:29)(cid:97)(cid:106)(cid:89) (cid:70)(cid:51)(cid:51)(cid:85) (cid:106)(cid:67)(cid:76)(cid:51) (cid:64)(cid:67)(cid:99)(cid:65) +(cid:106)(cid:82)(cid:97)(cid:119) (cid:67)(cid:78) (cid:47)(cid:107)(cid:84)(cid:72)(cid:81)(cid:105)(cid:89) +(cid:51)(cid:113)(cid:82)(cid:73)(cid:113)(cid:51) (cid:106)(cid:67)(cid:76)(cid:51) (cid:106)(cid:82) +(cid:486) (cid:12) (cid:34)(cid:37)(cid:49)(cid:39)(cid:51)(cid:38)(cid:50) +ADPFREQ +(cid:119)(cid:51)(cid:99) +(cid:105)(cid:51)(cid:97)(cid:76)(cid:67)(cid:78)(cid:29)(cid:106)(cid:51)(cid:89) +(cid:114)(cid:97)(cid:67)(cid:106)(cid:51) (cid:106)(cid:82) +(cid:47)(cid:107)(cid:84)(cid:72)(cid:81)(cid:105)(cid:89) +(cid:106)(cid:51)(cid:97)(cid:67)(cid:76)(cid:67)(cid:78)(cid:29)(cid:106)(cid:67)(cid:82)(cid:78) +(cid:106)(cid:67)(cid:76)(cid:51) (cid:97)(cid:51)(cid:29)(cid:44)(cid:64)(cid:51)(cid:48)(cid:93) +(cid:78)(cid:82) +(cid:97)(cid:51)(cid:126)(cid:78)(cid:51) (cid:76)(cid:51)(cid:99)(cid:64)(cid:46) (cid:67)(cid:56) +(cid:97)(cid:51)(cid:92)(cid:110)(cid:67)(cid:97)(cid:51)(cid:48) +re(cid:1)ne +re(cid:1)ne +re(cid:1)ne +re(cid:1)ne +end +time +Figure 12-2. Flow chart for ADPASS = 1. This algorithm may be summarized +as, “periodically refine” This method is recommended over ADPASS = 0 +when used with ADPENE, which implements look ahead. + VARIABLE +DESCRIPTION +option, the abscissa values define the refinement time, and the +ordinate values define the minimum element size. Only one +refinement level is performed per time step. An advantage of the +load curve option is that the mesh is adapted to honor the +minimum element size, but with the uniform option, IREFLG > 0, +this is not possible. +NOTE: If the element size defined with *DEFINE_CURVE is +positive, the element size will override the element size defined +with *CONTROL_ADAPTIVE and *DEFINE_SET_ADAPTIVE. +Also, if the element size defined with *DEFINE_CURVE is +negative the element size is used for refinement only. +For shell, ℎ-adapt the mesh when the FORMING contact surfaces +approach or penetrate the tooling surface depending on whether +is positive (approach) or negative +the value of ADPENE +(penetrates), respectively. The tooling adaptive refinement is +based on the curvature of the tooling. If ADPENE is positive the +takes place; +refinement generally occurs before contact +ADPENE +VARIABLE +DESCRIPTION +consequently, it is possible that the parameter ADPASS can be set +to 1 in invoke the one pass adaptivity. +For three dimensions 𝑟-adaptive solid remeshing (ADPOPT = 2 in +*PART), the mesh refinement is based on the curvature of the +tooling when ADPENE is positive. See Remark 6. +ADPTH +EQ.0.0: This parameter is ignored +GT.0.0: Absolute shell thickness level below which adaptive +remeshing should began. +LT.0.0: Element thickness reduction ratio. If the ratio of the +element thickness to the original element thickness is +less than 1.0+ADPTHK, the element will be refined. +This option works only if ADPTOL is nonzero. If thickness based +adaptive remeshing is desired without angle changes, then, set +ADPTOL to a large angle. +MEMORY +the machine and operating system +This flag can have two meanings depending on whether the +memory environmental variable is or is not set. The command +"setenv LSTC_MEMORY auto" (or for bourne shell “export +LSTC_MEMORY=auto”) sets the memory environmental variable +which causes LS-DYNA to expand memory automatically. Note +that automatic memory expansion is not always 100% reliable +depending on +level; +consequently, it is not yet the default. To see if this is set on a +particular machine type the command "env". If the environmen- +tal variable is not set then when memory usage reaches this +percentage, MEMORY, further adaptivity is prevented to avoid +exceeding the memory specified at execution time. Caution is +necessary since memory usage is checked after each adaptive +step, and, if the memory usage increases by more than the +residual percentage, 100-PERCENT, +calculation will +terminate. +If the memory environmental variable is set then when the +number of words of memory allocated reaches or exceeds this +value, MEMORY, further adaptivity is stopped. +the +ORIENT +This option applies to the FORMING contact option only. If this +flag is set to one (1), the user orientation for the contact interface +is used. If this flag is set to zero (0), LS-DYNA sets the global +orientation of the contact surface the first time a potential contact +is observed after the birth time. If slave nodes are found on both +sides of the contact surface, the orientation is set based on the +VARIABLE +DESCRIPTION +principle of "majority rules". Experience has shown that this +principle is not always reliable. +MAXEL +Adaptivity is stopped if this number of shells is exceeded. +IADPN90 +Maximum number of shells covering 90 degree of radii. See +Remark 5. +IADPGH +Fission flag for neighbor splitting. +EQ.0: split all neighbor shells +EQ.1: do not split neighbor shells +NCFREQ +IADPCL +ADPCTL +CBIRTH +Frequency of fission to fusion steps. For example, if NCFREQ = 4, +then fusion will occur on the fourth, eighth, twelfth, etc., fission +steps, respectively. If this option is used NCFREQ > 1 is +recommended. +Fusion will not occur until the fission level reaches IADPCL. +Therefore, if IADPCL = 2, MAXLVL = 5, any shell can be split into +256 shells. If the surface flattens out, the number of elements will +be reduced if the fusion option is active, i.e., the 256 elements can +be fused and reduced to 16. +Adaptivity error tolerance in degrees for activating fusion. It +follows the same rules as ADPOPT above. +Birth time for adaptive fusion. If ADPENE > 0, look-ahead +adaptivity is active. In this case, fission, based on local tool +curvature, will occur while the blank is still relatively flat. The +time value given for CBIRTH should be set to a time later in the +simulation after the forming process is well underway. +CDEATH +Death time for adaptive fusion. +LCLVL +Load curve ID of a curve that defines the maximum refinement +level as a function of time +CNLA +Limit angle for corner nodes. See Remark 7. +MMM2D +ADPERR +If non-zero, common boundaries of all adapted materials will be +merged. Only for 2D r-adaptivity +3-digit number, as “𝑋𝑌𝑌”, where “𝑋” and “𝑌𝑌” define the +options for the recovery techniques and the error estimators, +VARIABLE +DESCRIPTION +respectively, +For 𝑋: +EQ.0: superconvergent patch recovery (SPR) (default); +EQ.1: the least square fit of the stress to the nodes (Global L2); +EQ.2: error density SPR, as Δ𝑒 ̃ = Δ𝑒/Areaelement; +EQ.3: self-weighted SPR, as Δ𝑒 ̊ = √Δ𝑒 × 𝑒 +For 𝑌𝑌: +EQ.00: energy norm (default) +EQ.01: Cauchy 𝜎𝑥 +EQ.02: 𝜎𝑦 +EQ.03: 𝜎𝑧 +EQ.04: 𝜏𝑥𝑦 +EQ.05: 𝜏𝑦𝑧 +EQ.06: 𝜏𝑧𝑥 +EQ.07: effective plastic strain, 𝜀ep +EQ.08: pressure +EQ.09: von Mises +EQ.10: principal deviator stress s11 +EQ.11: 𝑆22 +EQ.12: 𝑆33 +EQ.13: Tresca +EQ.14: principal stress 𝜎11 +EQ.15: 𝜎22 +EQ.16: 𝜎33 +EQ.20: user subroutine “uadpval” to extract the numerical +solutions for recovery, and “uadpnorm” to provide an +error estimator. +D3TRACE +Flag that is either 0 or 1. If set to 1 then a d3plot state will be +output just before and after an adaptive step even though it may +not be requested. The reason for wanting to do this is to allow the +LS-PrePost particle trace algorithm to work in the case of +VARIABLE +DESCRIPTION +adaptivity. +IFSAND +Set this flag to “1” for forming of sandwiched parts with adaptive +blank mesh, see Remarks. Currently the adaptivity is limited to +only one layer of solid element, and applies to ADPOPT = 1 and 2 +only. +Remarks about 3D adaptivity: +1. Restarting. The d3dump and runrsf files contain all information necessary to +restart an adaptive run. This did not work in version 936 of LS-DYNA. +2. Related Field in *PART. In order for this control card to work, the flag +ADPOPT=1 must be set in the *PART definition. Otherwise, adaptivity will not +function. +3. Contact Types and Options. In order for adaptivity to work optimally, the +parameter SNLOG=1, must be set on Optional Control Card B in the *CON- +TACT Section. On disjoint tooling meshes the contact option *CONTACT_- +FORMING_… is recommended. +4. Root ID (RID) File. A file named “adapt.rid” is left on disk after the adaptive +run is completed. This file contains the root ID of all elements that are created +during the calculation, and it does not need to be kept if it is not used in post- +processing. +5. Note About IADPN90 Field. For all metal forming simulation, IADPN90 +should be set to -1. +6. Contact and ADPENE. In three dimensions when ADPENE>0 it is presumed +that the solid part to be adapted is on the slave side of a contact, and the “tool- +ing”, consisting of a shell surface, is on the master side of that same contact. +ADPENE>0 represents a distance from the tooling surface within which the +adapted mesh refinement of the slave part is influenced by the radius of curva- +ture of the tooling surface. This feature is currently unavailable in SMP and +SOFT=2 in *CONTACT. +Remarks about 2D r-adaptivity: +7. CNLA Field. In two dimensions 𝑟-adaptive remeshing, the generated new +mesh should have a node at each corner so that corners are not smoothed. By +default, the mesher will assume a corner wherever the interior angel between +adjacent edges is less than 110 degrees. Setting CNLA larger than 110 enables +angles larger than 110 to be corners. Care should be taken to avoid an unneces- +sarily large value of CNLA as this may prevent the mesher from generating +smooth meshes. +Remarks about mesh adaptivity for sandwiched parts (IFSAND): +8. Sandwiched parts (also called laminates) consist layers of solid elements (core) +sandwiched by one layer of shell elements each on top and bottom surface of +the solid elements, as shown in Figure 12-3. Common nodes are used for solid +and shell interface. Currently mesh adaptivity is limited to only one layer of +solid element with mesh refinements in-plane on both solids and shells. +Note sandwiched parts can be trimmed by setting ITYP = 1 in keyword +keyword +*CONTROL_FORMING_TRIMMING +*DEFINE_CURVE_TRIM. Trimming of sandwiched parts allows for multiple +layers of solids. +with +and +In a typical forming set up, the following cards need to be changed to activate +the sandwiched part mesh adaptivity: +*CONTROL_ADAPTIVE +$# adpfreq adptol adpopt maxlvl tbirth tdeath lcadp ioflag + &adpfq 4.0000E+00 1 4 0.0001.0000E+20 0 0 +$# adpsize adpass ireflg adpene adpth memory orient maxel + 0.90000 1 10.00000 0.000 0 0 0 +$# ladpn90 ladpgh ncfred ladpcl adpctl cbirth cdeath lclvl + -1 0 0 1 0.000 0.0001.0000E+20 0 +$ IFSAND + 1 +*PART +Mid-core layer of solid elements +$ PID SECID MID EOSID HGID GRAV ADPOPT TMID + 1 1 1 1 +Top layer of shell elements + 100 100 1 1 +Bottom layer of shell elements + 101 100 1 1 +Note IFSAND in *CONTROL_ADAPTIVE is set to “1” to activate the sandwich +part adaptivity; ADPOPT under *PART are all set to “1” to activate the adaptivity. +Revision Information: +9. +IFSAND is available starting in Rev 104365 in both SMP and MPP versions. +Later revisions may include improvements. +layer of +Top +shell elements +Only 1 layer of 3-D +solid elements are +allowed +Bottom layer of shell elements +Figure 12-3. Mesh adaptivity of sandwiched parts (IFSAND). +*CONTROL_ADAPTIVE_CURVE +Purpose: To refine the element mesh along a curve during or prior to sheet metal +forming simulation. All curves defined by the keyword *DEFINE_CURVE_TRIM are +used in the refinement. This option provides additional refinement to that created by +*CONTROL_ADAPTIVE. Additionally, pre-mesh refinement along a curve with +specific distance/range on both sides of the curve can be modeled when this keyword is +used together with *DEFINE_CURVE_TRIM_3D (by activating the variable TCTOL). +Lastly, the keyword can be used to refine mesh along a curve during trimming when +used together with the keyword *ELEMENT_TRIM. This feature only applies to shell +elements. + Card 1 +1 +2 +Variable +IDSET +ITYPE +Type +I +I +3 +N +I +4 +5 +6 +7 +8 +SMIN +ITRIOPT +F +I + VARIABLE +DESCRIPTION +IDSET +ITYPE +Set ID +Set type: +EQ.1: IDSET is shell set ID. +EQ.2: IDSET is part set ID. +N +Refinement option: +EQ.1: Refine until there are no adaptive constraints remaining +in the element mesh around the curve, subjected to the +maximum refinement level of 5. +GT.1: Refine no more than N levels. +SMIN +If the element dimension is smaller than this value, do not refine. +ITRIOPT +Option to refine an enclosed area of a trim curve. +EQ.0: Refine the elements along the trim curve. +EQ.1: Refine the elements along the trim curve and enclosed by +the trim curve. +Adaptive mesh refinement along a curve during a simulation: +In Figure 12-4, an example is shown to illustrate the mesh adaptivity along an enclosed +curve. Since the mesh refinement is controlled by the refinement level “N” and smallest +element size “SMIN”, care should be taken so not too many elements are generated +during the run. +A partial input example is listed below, where mesh will be refined by four levels, or to +no smaller than 0.3mm element edge length, along both sides of the curve defined by +IGES format file “adpcurves.iges”. +*INCLUDE +drawn.dynain +*DEFINE_CURVE_TRIM_3D +$ TCID TCTYPE TFLG TDIR TCTOL + 1 2 +adpcurves.iges +*CONTROL_ADAPTIVE_CURVE +$ IDSET ITYPE N SMIN + 1 2 4 0.3 +Since this method tends to create too many elements during refinement, the following +feature was added to address the issue. +Adaptive mesh refinement along a curve in the beginning of a simulation: +When TCTOL is defined under the keyword *DEFINE_CURVE_TRIM_3D, it is used as +a distance definition, and together with *CONTROL_ADAPTIVE_CURVE, the mesh +will be refined in the beginning of a (flanging, etc.) simulation, along both sides of the +defined curve, limited within the distance specified, as shown in Figures 12-5 and 12-6. +In addition, this feature works with the option 3D only. It is noted that the curve needs +to be sufficient close to the part, and this can be accomplished in LS-PrePost4.0 under +GeoTol/Project/Closest Proj/Project to Element/By Part. Furthermore, since the curve is +often made from some feature lines of forming tools, it is important the curve is re- +positioned closer to the blank, or better yet, is projected onto the blank; otherwise the +refinement will not take place. A partial input example is listed below, where mesh will +be refined within a range of 4.0mm, formed by 2.0mm distance (TCTOL = 2.0) of both +sides of the curve, defined by file “adpcurves.iges”. The maximum refine level is 4 and +minimum element size allowed is 0.3mm. +*INCLUDE +drawn.dynain +*DEFINE_CURVE_TRIM_3D +$ TCID TCTYPE TFLG TDIR TCTOL + 1 2 0 0 2.000 +adpcurves.iges +*CONTROL_ADAPTIVE_CURVE +$ IDSET ITYPE N SMIN + 1 2 4 0.3 +Mesh refinement along a curve is very useful during line die simulation. For example, +in a flanging simulation, a trimmed blank, where it is mostly flat in the flanging break +line in draw die, can be refined using a curve generated from the trim post radius. In +LS-PrePost 4.0, the curve can be generated using Curve/Spline/From Mesh/By Edge, check +Prop, and defining a large Ang to create a continuous curve along element edge. This +curve can then be projected onto the blank mesh using GeoTol/Project feature, to be used +as the curve file “adpcurves.iges” here. The mesh pre-refinement along curves are +implemented in ‘flanging’ process starting in LS-PrePost4.0 eZSetup for metal forming +application. In LS-PrePost4.3 eZSetup, improvements are made so adaptive mesh +refinement along a curve can be made without the need to define any tools. +In Figures 12-7, 12-8, 12-9, 12-10and 12-11, mesh pre-refinement along a curve is +demonstrated on the fender outer case. The effect of different TCTOL values on the +mesh refinement is obvious. +The keyword *INCLUDE_TRIM is recommended to be used at all times to include the +dynain file from a previous simulation, except in case where to-be-adapted sheet blank +has no stress and strain information (no *INITIAL_STRESS_SHELL, and *INITIAL_- +STRAIN_SHELL cards present in the sheet blank keyword or dynain file), then the +keyword *INCLUDE must be used. +Adaptive mesh refinement along a curve during trimming: +When this keyword *ELEMENT_TRIM is present, this keyword is used to refine meshes +during a trimming simulation. Coarse meshes along the trim curve can be refined prior +to trimming, leaving a more detailed and distinctive trim edge. A partial example input +deck is shown below: +*INCLUDE_TRIM +drawn.dynain +*ELEMENT_TRIM + 1 +*DEFINE_CURVE_TRIM_NEW +$# TCID TCTYPE TFLG TDIR TCTOL TOLN NSEED1 NSEED2 + 1 2 0 0.250 1 +doubletrim.iges +*DEFINE_TRIM_SEED_POINT_COORDINATES +$ NSEED X1 Y1 Z1 X2 Y2 Z2 + 1 -184.565 84.755 +*CONTROL_ADAPTIVE_CURVE +$# IDSET ITYPE N SMIN ITRIOPT + 1 2 3 3.0 0 +*CONTROL_CHECK_SHELL +$# PSID IFAUTO CONVEX ADPT ARATIO ANGLE SMIN + 1 1 1 1 0.25 150.0 0.18 +Where the keyword *ELEMENT_TRIM is used to define a deformable part set to be +trimmed. The keyword *DEFINE_CURVE_TRIM_NEW is used to define the trim curve +and +keyword +*DEFINE_TRIM_SEED_POINT_COORDINATES +is used to define a seed point +coordinate located on the portion that remains after trimming. The keyword +tolerance, +along +type, +with +trim +The +etc. +*CONTROL_ADAPTIVE_CURVE is used to define the adaptive mesh refinement level +and minimum element size along +the keyword +the +*CONTROL_CHECK_SHELL is used to repair and fix trimmed elements so they are +suitable for next stage simulation. More details can be found in each of the +corresponding keyword manual section. +trim curve. + Finally, +Figure 12-4. Mesh refinement along a curve +Curves defining +adaptive mesh location +Formed blank +Figure 12-5. Curves can be discontinuous and in one IGES file. +Figure 12-6. Define variable TCTOL to limit the mesh adaptivity area. +TCTOL +Trim panel +Curve defining pre-adaptive area +Flanging area mating +with hood inner +Figure 12-7. A complex mesh refinement example (NUMISHEET2002 +Fender). +Curve defining center +of adaptive band +Figure 12-8. Original mesh with target curves defined. +Figure 12-9. Mesh refinement with TCTOL = 0.5. +0.5 mm +1.0 mm +Figure 12-10. Mesh refinement with TCTOL = 1.0. +2.0 mm +Figure 12-11. Mesh refinement with TCTOL = 2.0. +*CONTROL_ALE +Purpose: Set global control parameters for the Arbitrary Lagrangian-Eulerian (ALE) +and Eulerian calculations. This command is required when solid element formulation +5, 6, 7, 11, or 12 is used. Parallel processing using SMP is not recommended when using +these element formulations, rather it is better to use MPP for good parallel processing +performance. + See *CONTROL_MPP_DECOMPOSITION_DISTRIBUTE_ALE_ELE- +MENTS. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DCT +NADV +METH +AFAC +BFAC +CFAC +DFAC +EFAC +Type +Default +I +1 + Card 2 +1 +I +0 +2 +I +1 +3 +F +0 +4 +F +0 +5 +F +0 +6 +F +0 +7 +F +0 +8 +Variable +START +END +AAFAC +VFACT +PRIT +EBC +PREF +NSIDEBC +Type +Default +F +0 +F +1020 +F +1 +F +F +10-6 +0.0 +I +0 +F +I +0.0 +none +This card is optional. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NCPL +NBKT +IMASCL +CHECKR +BEAMIN MMGPREF PDIFMX DTMUFAC +Type +Default +I +1 +I +50 +I +0 +F +F +0.0 +0.0 +I +0 +F +F +0.0 +0.0 +*CONTROL + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable OPTIMPP +Type +Default +I +0 + VARIABLE +DCT +DESCRIPTION +Flag to invoke alternate advection logic. Formerly flag to control +default continuum treatment: +NE.-1: Use default advection logic. +EQ.-1: Use alternate advection logic; generally recommended, +especially for simulation of explosives . +NADV +Number of cycles between advections (almost always set to 1). +METH +Advection method: +EQ.1: Donor cell with Half Index Shift (HIS), first order +accurate. +EQ.2: Van Leer with HIS, second order accurate. +EQ.-2: Van Leer with HIS: +Additionally,the monotonicity +condition is relaxed during advection process to better +preserve +*MAT_HIGH_EXPLOSIVE_BURN material +interfaces. +EQ.3: Donor cell with HIS modified to conserve total energy +over each advection step, in contrast to METH = 1 +which conserving internal energy . +AFAC +ALE smoothing weight factor - Simple average: +EQ.-1: turn smoothing off: +. +BFAC +CFAC +DFAC +ALE smoothing weight factor – Volume weighting +ALE smoothing weight factor – Isoparametric +ALE smoothing weight factor – Equipotential +VARIABLE +DESCRIPTION +EFAC +ALE smoothing weight factor – Equilibrium +START +END +Start time for ALE smoothing or start time for ALE advection if +smoothing is not used. +End time for ALE smoothing or end time for ALE advection if +smoothing is not used. +AAFAC +ALE advection factor (donor cell options, default = 1.0) +VFACT +Volume fraction limit for stresses in single material and void +formulation. All stresses are set to zero for elements with lower +volume fraction than VFACT. +EQ.0.0: set to default 10−6 +PRIT +A flag to turn on or off the pressure equilibrium iteration option +for multi-material elements . +EQ.0: Off (default) +EQ.1: On +EBC +Automatic Eulerian boundary condition . +EQ.0: Off +EQ.1: On with stick condition +EQ.2: On with slip condition +PREF +NSIDEBC +NCPL +Reference pressure to compute the internal forces. . +A node set ID (NSID) which is to be excluded from the EBC +constraint. +Number of Lagrangian cycles between coupling calculations. +This is typically done every cycle; therefore, its default is 1. This +is on optional card 3. +NBKT +IMASCL +*CONTROL +DESCRIPTION +Number of Lagrangian cycles between global bucket-sort +searches to locate the position of the Lagrangian structure (mesh) +relative to the ALE fluid (mesh). Default is 50. This is on optional +card 3. +LT.0: |NBKT| is a *DEFINE_CURVE ID defining a table: time +vs NBKT as defined above +EQ.0: (Default) NBKT = 50: +If the mesh is moving, NBKT is +adapted for the buckets to follow the mesh more closely +GT.0: NBKT remains constant. +A flag for turning ON/OFF mass scaling for ALE parts. The +global mass scaling control (parameter DT2MS under *CON- +TROL_TIMESTEP card) must be ON. If the run dt is lower than +the mass scaling dt, then IMASCL has the following effects: +EQ.0: (Default) No mass scaling for ALE parts. Print out +maximum 20 warnings. +EQ.1: No mass scaling for ALE parts. Stop the run. +EQ.2: Do mass scaling for ALE parts (the result may not be +correct due to this scaling). +EQ.3: No mass scaling for ALE parts. Timestep is taken as the +minimum of the ALE timestep and DT2MS. +CHECKR +BEAMIN +A parameter for reducing or eliminating an ALE pressure locking +pattern. It may range from 0.01 to 0.1 . +Flag to align the dynamics of plain strain and axisymmetric +beams in 2D FSI ALE models to their shell counterparts in 3D FSI +ALE models: +EQ.0.0: Off (default) +EQ.1.0: On +MMGPREF +*CONTROL_ALE +DESCRIPTION +MMGPREF selects the method that is used to include a reference +pressure in a calculation involving ALE multi-material groups +. +LT.0: |MMGPREF| is the id of a table defined by *DEFINE_- +CURVE where the abscissas are the multi-material group +ids and the ordinates are the reference pressures. +If a multi-material group is not in the table, its reference +pressure is default to PREF. +For situations in which the reference pressures are time +dependent *DEFINE_TABLE should be used instead of +*DEFINE_CURVE. The table should consist of a set of +curves indexed by group ID that encode reference pres- +sure as a function of time. If 𝑛 groups need reference +pressure histories, *DEFINE_TABLE will have 𝑛 lines +followed by 𝑛 corresponding *DEFINE_CURVE. +EQ.0: Off (default). +EQ.1: Obsolete: Use MMGPREF < 0 instead +EQ.2: Obsolete: Use MMGPREF < 0 instead +PDIFMX +Maximum of pressure difference between neighboring ALE +elements under which the stresses are zeroed out: +EQ.0: Off (default) +GT.0: On +DTMUFAC +Scale a time step called DTMU that depends on the dynamic +viscosity 𝜇, the initial density 𝜌, and an element characteristic +length ℓ: +DTMU = +𝜌ℓ2 +2𝜇 +DTMU is emitted by the element to the solver as an element time +step, thereby making DTMU an upper bound on the global time +step. +EQ.0: Off (default) +GT.0: On +Optimize the MPP communications in the penalty coupling +(*CONSTRAINED_LAGRANGE_IN_SOLID, CTYPE = 4) and +group ALE parts together for the element processing. +EQ.0: Off (default) +EQ.1: On +*CONTROL_ALE + VARIABLE +OPTIMPP +Remarks: +1. The PRIT Field. Most of the fast transient applications do not need this feature. +It could be used in specific slow dynamic problems for which material constitu- +tive laws with very different compressibility are linear and the stresses in multi- +material elements require to be balanced. +2. The EBC Field. This option, used for EULER formulations. It automatically +defines velocity boundary condition constraints for the user. The constraints, +once defined, are applied to all nodes on free surfaces of an Eulerian domain. +For problems where the normal velocity of the material at the boundary is zero +such as injection molding problems, the automatic boundary condition parame- +ter is set to 2. This will play the same role as the nodal single point constraint. +For EBC = 1, the material velocity of all free surface nodes of an Eulerian do- +main is set to zero. +3. The PREF Field. The reference pressure PREF is subtracted from the stresses +before computing the internal forces. Thus PREF is equivalent to applying a +*LOAD_SEGMENT card to balance the internal pressure along the ALE mesh +boundaries. PREF is applied to all the materials in the ALE mesh. So, before +the subtraction for MMGPREF > 0, PREF is added to the stresses of some mate- +rials. +On another hand, MMGPREF < 0 subtracts a reference pressure depending on +ALE MMG ID. The shift of the stresses by PREF is not necessary (and so it can +not be seen in the LS-PrePost fringe of the pressures). For example, if a model +has 3 ALE groups: air with an initial pressure of 1.0 bar, an explosive material, +and water, the reference pressure of the first group would be 1.0 bar whereas +the other groups would have none. In that case, PREF = 0.0 bar and +MMGPREF = -LCID where LCID is the id of the following table: +*DEFINE_CURVE +lcid +1,1.0 +2,0.0 +3,0.0 +4. CHECKR Field for One Point Integration. Due to one point integration, ALE +elements may experience a spatial instability in the pressure field referred to as +checker boarding. CHECKR is a scale for diffusive flux calculation to alleviate +this problem. +5. METH=3 for Conserving Total Energy. Generally, it is not possible to +conserve both momentum and kinetic energy (KE) at the same time. Typically, +internal energy (IE) is conserved and KE may not be. This may result in some +KE loss (hence, total energy loss). For many analyses this is tolerable, but for +airbag application, this may lead to the reduction of the inflating potential of +the inflator gas. METH=3 tries to eliminate this loss in KE over the advection +step by storing any loss KE under IE, thus conserving total energy of the sys- +tem. +6. Smoothing Factors. All the smoothing factors (AFAC, BFAC, CFAC, DFAC, +EFAC) are generally most applicable to ELFORM = 5 (single material ALE for- +mulation). The ALE smoothing feature is not supported by MPP versions. +7. First Pass Recommendations. Although this card has many parameters, only +a few are required definitions. Typically, one can try setting NADV=1, +METH=1, AFAC=-1 and the rest as “0” as a starting point. Sometimes when +needed, PREF should be defined. This is adequate for most cases. Sometimes it +may be appropriate to fine-tune the model by changing METH to 2 or 3 de- +pending on the physics. +8. Pressure Checker Boarding. Because the internal forces are located at the +nodes, while the pressure is stored at the element center, sometimes a "checker- +board pattern" arises in the pressure distribution. It is a kind of locking effect +that normally occurs only in problems having very small volumetric strains, i.e., +at small pressures. “CHECKR” is designed for alleviating this problem. +9. The DCT Field. Starting with the R5 the DCT field can be used to invoke an +alternate advection scheme. DCT=-1 is recommended over the default scheme, +especially for simulating explosives and includes the following major changes: +a) Relaxes an artificial limit on the expansion ratio limit. The default limit +improves stability in some situations but can overestimate the explosive +impulse. +b) Corrects redundant out-flux of material at corner elements. The redun- +dancy can lead to negative volume. +c) Removes several artificial constraints in the advection which were origi- +nally implemented to assist in stability but are no longer needed. +10. METH = -2. The METH = -2 advection type is the same as METH = 2 with only +one exception. It employs a looser constraint on monotonicity requirement +during ALE advection. When METH = 2, for each advection process along +three directions (front/back, top/bottom, left/right), the maximum/minimum +values for advected history variables in the three elements along that direction +are capped. METH = -2 relaxed the monotonicity condition so that the advec- +ted value is capped at the maximum/minimum value in the element itself and +its neighboring 26 elements. This option, in certain conditions, can better pre- +serve the material interface for materials defined with *MAT_HIGH_EXPLO- +SIVE_BURN. +*CONTROL_BULK_VISCOSITY +Purpose: Reset the default values of the bulk viscosity coefficients globally. This may +be advisable for shock wave propagation and some materials. Bulk viscosity is used to +treat shock waves. A viscous term q is added to the pressure to smear the shock +discontinuities into rapidly varying but continuous transition regions. With this +method the solution is unperturbed away from a shock, the Hugoniot jump conditions +remain valid across the shock transition, and shocks are treated automatically. + Card 1 +Variable +1 +Q1 +Type +F +2 +Q2 +F +Default +1.5 +.06 +3 +4 +5 +6 +7 +8 +TYPE +BTYPE +I +1 +I +0 + VARIABLE +DESCRIPTION +Q1 +Q2 +Default quadratic viscosity coefficient. +Default linear viscosity coefficient. +TYPE +Default bulk viscosity type, IBQ (Default = 1) +EQ.-2: standard (also types 2, 4, 10, 16, and 17). With this +option the internal energy dissipated by the viscosity in +the shell elements is computed and included in the +overall energy balance. +EQ.-1: standard (also types 2, 4, 10, 16, and 17 shell elements). +The internal energy is not computed in the shell ele- +ments. +EQ.+1: standard: Solid elements only and internal energy is +always computed and included in the overall energy +balance. +EQ.+2: Richards-Wilkins: Two-dimensional plane strain and +axisymmetric solid elements only. Internal energy is +always computed and included in the overall energy +balance. +VARIABLE +DESCRIPTION +BTYPE +Beam bulk viscosity type (Default = 0) +EQ.0: The bulk viscosity is turned off for beams. +EQ.1: The bulk viscosity is turned on for beam types 1 and 11. +The energy contribution is not included in the overall +energy balance. +EQ.2: The bulk viscosity is turned on for beam type 1 and 11. +The energy contribution is included in the overall energy +balance. +Remarks: +The bulk viscosity creates an additional additive pressure term given by: +𝑞 = { +𝜌𝑙(𝑄1𝑙𝜀̇𝑘𝑘 +2 − 𝑄2𝑎𝜀̇𝑘𝑘) +𝜀̇𝑘𝑘 < 0 +𝜀̇𝑘𝑘 ≥ 0 +where 𝑄1 and 𝑄2 are dimensionless input constants which default to 1.5 and .06, +respectively, and 𝑙 is a characteristic length given as the square root of the area in two +dimensions and as the cube root of the volume in three, 𝑎 is the local sound speed, 𝑄1 +defaults to 1.5 and 𝑄2 defaults to .06. See Chapter 21 in the LS-DYNA Theory Manual +for more details. +The Richards-Wilkins, see [Richards 1965, Wilkins 1976], bulk viscosity considers the +directional properties of the shock wave. This has the effect of turning off the bulk +viscosity in converging geometries minimizing the effects of “q-heating”. The standard +option is active whenever the volumetric strain rate is undergoing compression even +though no shock waves are present. +Purpose: Check for various problems in the mesh. +*CONTROL_CHECK_SHELL +Part cards. Include one card for each part or part set to be checked. The next keyword +(“*”) card terminates this input. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PSID +IFAUTO +CONVEX +ADPT +ARATIO +ANGLE +SMIN +Type +Default +I +0 +I +0 +I +1 +I +1 +F +F +F +0.25 +150.0 +0.0 + VARIABLE +DESCRIPTION +PSID +Part or part set ID to be checked: +EQ.0: do not check +GT.0: part ID +LT.0: part set ID +IFAUTO +Flag to automatically correct bad elements: +EQ.0: write warning message only +EQ.1: fix bad element, write message +CONVEX +Check element convexity (internal angles less than 180 degrees) +EQ.0: do not check +EQ.1: check +ADPT +Check adaptive constraints +EQ.0: do not check +EQ.1: check +ARATIO +Minimum allowable aspect ratio. Elements which do not meet +minimum aspect ratio test will be treated according to IFAUTO +above. +ANGLE +Maximum allowable internal angle. Elements which fail this test +will be treated according to IFAUTO above. +DESCRIPTION +Minimum element size. Elements which fail this test will be +treated according to IFAUTO above. + VARIABLE +SMIN +Remarks: +1. For the SHELL option, shell element integrity checks which have been +identified as important in metal forming applications are performed. These +checks can improve springback convergence and accuracy. This option will +repair bad elements created, for example, during trimming operations. +2. +3. +If the convexity test is activated, all failed elements will be fixed regardless of +IFAUTO. +In addition to illegal constraint definitions (slave which is also a master), checks +are performed for mesh connectivities which have been found to cause conver- +gence trouble in implicit springback applications. +4. Variable SMIN should be set to 1/4 to 1/3 of smallest pre-trim element length. +In an example below, smallest element length pre-trim is 0.6mm, which makes +SMIN to be 0.18: +*CONTROL_CHECK_SHELL +1,1,1,1,0.25,150.0,0.18 +$ smin=(0.25~0.3)*smallest pre-trim element length, which is ~0.6 mm. +5. Shell checking is done during the input phase (in sprinback input deck) in LS- +DYNA R5 Revision 63063 and prior releases. After the Revision, it is done after +trimming is completed. Therefore the keyword should be included in a trim- +ming input deck. +*CONTROL_COARSEN +Purpose: Adaptively de-refine (coarsen) a shell mesh by selectively merging four +adjacent elements into one. Adaptive constraints are added and removed as necessary. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ICOARSE +ANGLE +NSEED +PSID +SMAX +Type +Default + Card 2 +Variable +Type +Default +I +0 +1 +N1 +I +0 +F +none +2 +N2 +I +0 +I +0 +3 +N3 +I +0 +I +0 +4 +N4 +I +0 +F +0 +5 +N5 +I +0 + VARIABLE +DESCRIPTION +ICOARSE +Coarsening flag: +EQ.0: do not coarsen (default) +6 +N6 +I +0 +7 +N7 +I +0 +8 +N8 +I +0 +EQ.1: coarsen mesh at beginning of simulation for forming +model +EQ.2: coarsen mesh at beginning of simulation for crash model +ANGLE +Allowable angle change between neighboring elements. Adjacent +elements which are flat to within ANGLE degrees are merged. +(Suggested starting value = 8.0 degrees) +NSEED +Number of seed nodes (optional). +EQ.0: use only automatic searching. +GT.0: the number of seed nodes with which to supplement the +search algorithm. See Remark 2. NSEED must be an +integer less than or equal to 8. +VARIABLE +DESCRIPTION +PSID +SMAX +Part set ID. All the parts defined in this set will be prevented +from been coarsened. +Maximum element size. For ICOARSE = 2, no elements larger +than this size will be created. +N1, …, N8 +Optional list of seed node IDs for extra searching. If no seed +nodes are specified, leave card 2 blank. +Remarks: +1. Coarsening is performed at the start of a simulation. The first plot state +represents the coarsened mesh. By setting the termination time to zero and +including the keyword *INTERFACE_SPRINGBACK_LSDYNA a keyword +input deck can be generated containing the coarsened mesh. +2. By default, an automatic search is performed to identify elements for coarsen- +ing. In some meshes, isolated regions of refinement may be overlooked. Seed +nodes can be identified in these regions to assist the automatic search. Seed +nodes identify the central node of a four-element group which is coarsened into +a single element if the angle criterion is satisfied. +3. The keyword *DEFINE_BOX_COARSEN can be used to indicate regions of the +mesh which are protected from coarsening. +*CONTROL_CONTACT +Purpose: Change defaults for computation with contact surfaces. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SLSFAC RWPNAL +ISLCHK +SHLTHK +PENOPT +THKCHG +ORIEN +ENMASS +Type +F +F +Default +.1 +none +Remarks + Card 2 +1 +2 +I +1 +3 +3 +I +0 +I +1 +I +0 +I +1 +I +0 +4 +5 +6 +7 +8 +Variable +USRSTR USRFRC +NSBCS +INTERM +XPENE +SSTHK +ECDT +TIEDPRJ +Type +Default +I +0 +I +0 +I +10-100 +I +0 +F +4.0 +I +0 +I +0 +I +0 +Remaining cards are optional.† +The optional cards apply only to the following contact types: +*SINGLE_SURFACE +*AUTOMATIC_GENERAL +*AUTOMATIC_SINGLE_SURFACE +*AUTOMATIC_NODES_TO_… +*AUTOMATIC_SURFACE_… +*AUTOMATIC_ONE_WAY_… +*ERODING_SINGLE_SURFACE. +The friction coefficients SFRIC, DFRIC, EDC, and VFC are active only when *PART_- +CONTACT is invoked with FS = -1 in *CONTACT, and the corresponding frictional +coefficients in *PART_CONTACT are set to zero. This keyword’s TH, TH_SF, and +PEN_SF override the corresponding parameters in *CONTACT, but will not override +corresponding nonzero parameters in *PART_CONTACT. + Card 3 +1 +2 +3 +4 +Variable +SFRIC +DFRIC +EDC +VFC +Type +F +F +F +F +5 +TH +F +6 +7 +8 +TH_SF +PEN_SF +PTSCL +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +1.0 + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IGNORE +FRCENG SKIPRWG OUTSEG SPOTSTP SPOTDEL SPOTHIN +Type +Default +I +0 + Card 5 +1 +I +0 +2 +I +0 +3 +I +0 +4 +I +0 +5 +I +F +0 +inactive +6 +7 +8 +Variable +ISYM +NSEROD RWGAPS RWGDTH +RWKSF +ICOV +SWRADF +ITHOFF +Type +Default +I +0 +I +0 +I +0 +F +0. +F +1.0 +I +0 +F +0. +I +Card 6 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SHLEDG +PSTIFF +ITHCNT +TDCNOF +FTALL +SHLTRW +IGACTC +Type +Default +I +0 +I +0 +I +0 +I +0 +I +0 +F +0. +I +0 + VARIABLE +DESCRIPTION +SLSFAC +Scale factor for sliding interface penalties, SLSFAC: +EQ.0: default = .1. +RWPNAL +Scale factor for rigid wall penalties, which treat nodal points +interacting with rigid walls, RWPNAL. The penalties are set so +that an absolute value of unity should be optimal; however, this +penalty value may be very problem dependent. + If rig- +id/deformable materials switching is used, this option should be +used if the switched materials are interacting with rigid walls. +LT.0.0: all nodes are treated by the penalty method. This is +required for implicit calculations. Since seven (7) vari- +ables are stored for each slave node, only the nodes +that may interact with the wall should be included in +the node list. +EQ.0.0: the constraint method is used and nodal points which +belong to rigid bodies are not considered. +GT.0.0: rigid bodies nodes are treated by the penalty method +and all other nodes are treated by the constraint meth- +od. +ISLCHK +Initial penetration check in contact surfaces with indication of +initial penetration in output files : +EQ.0: the default is set to 1, +EQ.1: no checking, +EQ.2: full check of initial penetration is performed. +VARIABLE +SHLTHK +DESCRIPTION +Flag for consideration of shell thickness offsets in non-automatic +surface-to-surface and non-automatic nodes-to-surface +type +contacts. Shell thickness offsets are always included in single +surface, constraint-based, automatic surface-to-surface, and +automatic nodes-to-surface contact types : +EQ.0: thickness is not considered, +EQ.1: thickness is considered but rigid bodies are excluded, +EQ.2: thickness is considered including rigid bodies. +PENOPT +Penalty stiffness value option. For default calculation of the +penalty value please refer to the LS-DYNA Theory Manual. +EQ.0: the default is set to 1, +EQ.1: minimum of master segment and slave node (default for +most contact types), +EQ.2: use master segment stiffness (old way), +EQ.3: use slave node value, +EQ.4: use slave node value, area or mass weighted, +EQ.5: same as 4 but inversely proportional to the shell +thickness. This may require special scaling and is not +generally recommended. +Options 4 and 5 can be used for metal forming calculations. +THKCHG +Shell thickness changes considered in single surface contact: +EQ.0: no consideration (default), +EQ.1: shell thickness changes are included. +ORIEN +Optional automatic reorientation of contact interface segments +during initialization. See Remark 4. +EQ.0: default is set to 1. +EQ.1: active for automated (part) input only. Contact surfaces +are given by *PART definitions. +EQ.2: active for manual (segment) and automated (part) input. +EQ.3: inactive for non-forming contact. +EQ.4: inactive for *CONTACT_FORMING types and *CON- +TACT_DRAWBEAD. +ENMASS +USRSTR +USRFRC +NSBCS +*CONTROL_CONTACT +DESCRIPTION +Treatment of the mass of eroded nodes in contact. This option +affects all contact types where nodes are removed after +surrounding elements fail. Generally, the removal of eroded +nodes makes the calculation more stable; however, in problems +where erosion is important the reduction of mass will lead to +incorrect results. ENMASS is not supported when SOFT = 2 on +optional card A. +EQ.0: eroding nodes are removed from the calculation. +EQ.1: eroding nodes of solid elements are retained and +continue to be active in contact. +EQ.2: the eroding nodes of solid and shell elements are +retained and continue to be active in contact. +Storage per contact interface for user supplied interface control +subroutine, see Appendix F. If zero, no input data is read and no +interface storage is permitted in the user subroutine. This storage +should be large enough to accommodate input parameters and +any history data. This input data is available in the user supplied +subroutine. +Storage per contact interface for user supplied interface friction +subroutine, see Appendix G. If zero, no input data is read and no +interface storage is permitted in the user subroutine. This storage +should be large enough to accommodate input parameters and +any history data. This input data is available in the user supplied +subroutine. +Number of cycles between contact searching using three +dimensional bucket searches, defaults recommended. For Mortar +contact (option MORTAR on the CONTACT card), the default is +100. +INTERM +Flag for intermittent searching in old surface-to-surface contact +using the interval specified as NSBCS above: +EQ.0: off, +EQ.1: on. +VARIABLE +XPENE +DESCRIPTION +Contact surface maximum penetration check multiplier. If the +small penetration checking option, PENCHK, on the contact +surface control card is active, then nodes whose penetration then +exceeds the product of XPENE and the element thickness are set +free, see *CONTACT_OPTION_… +EQ.0: default is set to 4.0. +SSTHK +Flag for using actual shell thickness in single surface contact +logic-types 4, 13, 15 and 26. See Remarks 1 and 2. +EQ.0: Actual shell thickness is not used in the contacts. +(default), +EQ.1: Actual shell thickness is used in the contacts. (sometimes +recommended for metal forming calculations). +ECDT +Time step size override for eroding contact: +EQ.0: contact time size may control Dt. +EQ.1: contact is not considered in Dt determination. +TIEDPRJ +Bypass projection of slave nodes to master surface in types: +*CONTACT_TIED_NODES_TO_SURFACE +*CONTACT_TIED_SHELL_EDGE_TO_SURFACE +*CONTACT_TIED_SURFACE_TO_SURFACE +Tied interface options: +EQ.0: eliminate gaps by projection nodes, +EQ.1: bypass projection: Gaps create +rotational constraints +which can substantially affect results. +SFRIC +Default static coefficient of friction +DFRIC +Default dynamic coefficient of friction +EDC +VFC +TH +Default exponential decay coefficient +Default viscous friction coefficient +Default contact thickness +TH_SF +Default thickness scale factor +VARIABLE +DESCRIPTION +PEN_SF +Default local penalty scale factor +PTSCL +IGNORE +Scale factor on the contact stress exerted onto shells formulations +25, 26, and 27. When DOF = 3 the scale factor also applies to shell +formulations 2, and 16. +Ignore initial penetrations in the *CONTACT_AUTOMATIC +options. In the SMP contact this flag is not implement for the AU- +TOMATIC_GENERAL option. “Initial” in this context refers to +the first timestep that a penetration is encountered. This option +can also be specified for each interface on the third optional card +under the keyword, *CONTACT. The value defined here will be +the default. +EQ.0: move nodes to eliminate initial penetrations in the model +definition. +EQ.1: allow initial penetrations to exist by tracking the initial +penetrations. +EQ.2: allow initial penetrations to exist by tracking the initial +penetrations. However, penetration warning messages +are printed with the original coordinates and the recom- +mended coordinates of each slave node given. +FRCENG +Flag to activate the calculation of frictional sliding energy: +EQ.0: do not calculate, +EQ.1: calculate frictional energy in contact and store as +“Surface Energy Density” in the binary INTFOR file. +Convert mechanical frictional energy to heat when doing +a coupled thermal-mechanical problem. When PKP_- +SEN = 1 on the keyword card *DATABASE_EXTENT_BI- +NARY, it is possible to identify the energies generated on +the upper and lower shell surfaces, which is important in +metal forming applications. This data is mapped after +each H-adaptive remeshing. +EQ.2: Same as behavior as above (set to 1) except that frictional +energy is not converted to heat. +VARIABLE +DESCRIPTION +SKIPRWG +Flag not to display stationary rigid wall by default. +EQ.0: generate 4 extra nodes and 1 shell element to visualize +stationary planar rigid wall. +EQ.1: do not generate stationary rigid wall. +OUTSEG +Flag to output each beam spot weld slave node and its master +segment for contact type: *CONTACT_SPOTWELD into the +d3hsp file. +EQ.0: no, do not write out this information. +EQ.1: yes, write out this information. +SPOTSTP +If a spot weld node or face, which is related to a *MAT_- +SPOTWELD beam or solid element, respectively, cannot be found +on the master surface, should an error termination occur? +SPOTDEL +EQ.0: no, silently delete the weld and continue, +EQ.1: yes, print error message and terminate, +EQ.2: no, delete the weld, print a message, and continue, +EQ.3: no, keep the weld. This is not recommended as it can +lead to instabilities. +This option controls the behavior of spotwelds when the parent +element erodes. When SPOTDEL is set to 1, the beam or solid +spotweld is deleted and the tied constraint is removed when the +parent element erodes. Parent element is the element to which +the slave node is attached using the TIED interface. This option +also works for SPRs, i.e. they automatically fail if at least one of +the parent elements fails. To avoid instabilities, this option is +recommended to be set to 1 for any situation in which the parent +element is expected to erode. +EQ.0: no, do not delete the spot weld beam or solid element or +SPR, +EQ.1: yes, delete the weld elements or SPRs when the attached +shells on one side of the element fail. +On vector processors this option can significantly slow down the +calculation if many weld elements fail since the vector lengths are +reduced. On non-vector processors the cost-penalty is minimal. +SPOTHIN +*CONTROL_CONTACT +DESCRIPTION +Optional thickness scale factor. If active, define a factor greater +than zero, but less than one. Premature failure of spot welds can +occur due to contact of the spot welded parts in the vicinity of the +spot weld. This contact creates tensile forces in the spot weld. +Although this may seems physical, the compressive forces +generated in the contact are large enough to fail the weld in +tension before failure is observed in experimental test. With this +option, the thickness of the parts in the vicinity of the weld are +automatically scaled, the contact forces do not develop, and the +problem is avoided. We recommend setting the IGNORE option +to 1 or 2 if SPOTHIN is active. This option applies only to the +AUTOMATIC_SINGLE_SURFACE option. See Remark 5. +ISYM +Symmetry plane option default for automatic segment generation +when contact is defined by part ID’s: +EQ.0: off, +EQ.1: do not include faces with normal boundary constraints +(e.g., segments of brick elements on a symmetry plane). +This option is important to retain the correct boundary conditions +in the model with symmetry. +NSEROD +Flag to use one-way node to surface erosion +EQ.0: use two-way algorithm +EQ.1: use one-way algorithm +RWGAPS +Flag to add rigid wall gap stiffness, see parameter RWGDTH +below. +EQ.1: add gap stiffness +EQ.2: do not add gap stiffness +RWGDTH +RWKSF +Death time for gap stiffness. After this time the gap stiffness is no +longer added. +Rigid wall penalty scale factor for contact with deformable parts +during implicit calculations. This value is independent of SLS- +FAC and RWPNAL. If RWKSF is also specified in *RIGID- +WALL_PLANAR, the stiffness is scaled by the product of the two +values. +VARIABLE +ICOV +DESCRIPTION +the +covariant +Invokes +formulation of Konyukhov and +Schweizerhof in the FORMING contact option. This option is +available in the third revision of version 971, but is not +recommended since it is still being implemented. +EQ.0: standard formulation (default) +EQ.1: covariant contact formulation. +SWRADF +Spot weld radius scale factor for neighbor segment thinning +EQ.0: neighbor segments not thinned (default) +GT.0: The radius of beam spot welds are scaled by SWRADF +when searching for close neighbor segments to thin. +ITHOFF +Flag for offsetting thermal contact surfaces for thick thermal +shells +EQ.0: No offset, if thickness is not included in the contact the +heat will be transferred between the mid-surfaces of the +corresponding contact segments (shells). +EQ.1: Offsets are applied so that contact heat transfer is always +between the outer surfaces of the contact segments +(shells). +SHLEDG +Flag for assuming edge shape for shells when measuring +penetration. This is available for segment based contact +EQ.0: Shell edges are assumed round (default), +EQ.1: Shell edges are assumed square and are flush with the +nodes +PSTIFF +Flag to choose the method for calculating the penalty stiffness. +This is available for segment based contact . See Remark 6. +EQ.0: Based on material density and segment dimensions +(default), +EQ.1: Based on nodal masses. +VARIABLE +DESCRIPTION +ITHCNT +Thermal contact heat transfer methodology +LT.0: conduction evevenly distributed (pre R4) +EQ.0: default set to 1 +EQ.1: conduction weighted by shape +functions, reduced +intergration +EQ.2: conduction weighted by shape functions, full integration +TDCNOF +Tied constraint offset contact update option. +EQ.0: Update velocities and displacements from accelerations +EQ.1: Update velocities and accelerations from displacements. +This option is recommended only when there are large +angle changes where the default does not maintain a +constant offset to a small tolerance. This latter option is +not as stable as the default and may require additional +damping for stability. See *CONTROL_BULK_VISCOSI- +TY and *DAMPING_PART_STIFFNESS. +Option to output contact forces to RCFORC for all 2 surface force +transducers when the force transducer surfaces overlap. See +Remark 7. +EQ.0: Output to the first force transducer that matches +(default) +EQ.1: Output to all force transducers that match. +FTALL +SHLTRW +Optional shell thickness scale factor for contact with rigid walls. +Shell thickness is not considered when SHLTRW = 0 (default). +SHLTRW = 0.5 will result in an offset of half of shell thickness in +contact with rigid walls. +IGACTC +Options to use isogeometric shells for contact detection when +contact involves isogeometric shells: +EQ.0: contact between interpolated nodes and interpolated +shells +EQ.1: contact between interpolated nodes and isogeometric +shells +*CONTROL +1. Shell Thickness. The shell thickness change option (ISTUPD) must be +activated in *CONTROL_SHELL and a nonzero flag specified for SHLTHK +above before the shell thickness changes can be included in the surface-to- +surface contact types. If thickness changes are to be included in the single sur- +face contact algorithms, an additional flag must be set, see THKCHG above. +Although the contact algorithms that include the shell thickness are relatively +recent, they work in parallel (MPI) Dyna are fully optimized. The searching in +these algorithms is considerably more extensive and therefore slightly more +expensive. +2. Upper Limit on Thickness. In the single surface contacts types SINGLE_SUR- +FACE, AUTOMATIC_SINGLE_SURFACE, AUTOMATIC_GENERAL, AU- +TOMATIC_GENERAL_INTERIOR and ERODING_SINGLE_SURFACE, the +default contact thickness is taken as the smaller of two values — the shell thick- +ness or 40% of the minimum edge length. (NOTE: Minimum edge length is +calculated as min(N4-to-N1, N1-to-N2, N2-to-N3). N3-to-N4 is neglected ow- +ing to the possibility of the shell being triangular.) This may lead to unexpected +results if it is the intent to include thickness effects when the in-plane shell +element dimensions are less than the thickness. The default is based on years of +experience where it has been observed that sometimes rather large nonphysical +thicknesses are specified to achieve high stiffness values. Since the global +searching algorithm includes the effects of shell thicknesses, nonphysical thick- +ness dimensions slow the search down considerably. +3. +Initial Penetration Check. As of version 950 the initial penetration check +option is always performed regardless of the value of ISLCHK. If you do not +want to remove initial penetrations then set the contact birth time so that the contact is not active at time 0. +4. Automatic Reorientation. Automatic reorientation requires offsets between +the master and slave surface segments. The reorientation is based on segment +connectivity and, once all segments are oriented consistently based on connec- +tivity, a check is made to see if the master and slave surfaces face each other +based on the right hand rule. If not, all segments in a given surface are reori- +ented. This procedure works well for non-disjoint surfaces. If the surfaces are +disjoint, the AUTOMATIC contact options, which do not require orientation, +are recommended. In the FORMING contact options automatic reorientation +works for disjoint surfaces. +5. Neighbor Segment Thinning Option. If SPOTHIN is greater than zero and +SWRADF is greater than zero, a neighbor segment thinning option is active. +The radius of a beam spot weld is scaled by SWRADF, and then a search is +made for shell segments that are neighbors of the tied shell segments that are +touched by the weld but not tied by it. +6. Segment Masses for Penalty Stiffness. Segment based contact calculates a penalty stiffness based on the solution time step +and the masses of the segments in contact. By default, segment masses are +calculated using the material density of the element associated with the seg- +ment and the volume of the segment. This method does not take into account +added mass introduced by lumped masses or mass scaling and can lead to +stiffness that is too low. Therefore, a second method (PSTIFF = 1) was added +which estimates the segment mass using the nodal masses. Setting a PSTIFF +values here will set the default values for all interfaces. The PSTIFF option can +also be specified for individual contact interfaces by defining PSTIFF on option- +al card F of *CONTACT. +7. Force Transducer Search Option. Two surface force transducers measure the +contact force from any contact interfaces that generate force between the slave +and master surfaces of the force transducer. When contact is detected, a search +is made to see if the contact force should be added to any 2 surface force trans- +ducers. By default, when a force transducer match is found, the force is added +and the search terminates. When FTALL = 1, the search continues to check for +other two surface force transducer matches. This option is useful when the +slave and master force transducer surfaces overlap. If there is no overlap, the +default is recommended. +*CONTROL +Purpose: Change defaults for MADYMO3D/CAL3D coupling, see Appendix I. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +UNLENG +UNTIME +UNFORC +TIMIDL +FLIPX +FLIPY +FLIPZ +SUBCYL +Type +F +Default +1. +F +1. +F +1. +F +0. +I +0 +I +0 +I +0 +I +1 + VARIABLE +UNLENG +UNTIME +UNFORC +TIMIDL +FLIPX +DESCRIPTION +Unit conversion factor for length. MADYMO3D/GM-CAL3D +lengths are multiplied by UNLENG to obtain LS-DYNA lengths. +Unit conversion factor for time, UNTIME. MADYMO3D/GM- +CAL3D time is multiplied by UTIME to obtain LS-DYNA time. +Unit conversion factor for force, UNFORC. MADYMO3D/GM- +CAL3D force is multiplied by UNFORC to obtain LS-DYNA +force. +Idle time during which CAL3D or MADYMO is computing and +LS-DYNA remains inactive. Important for saving computer time. +Flag for flipping X-coordinate of CAL3D/MADYMO3D relative +to the LS-DYNA model: +EQ.0: off, +EQ.1: on. +FLIPY +Flag for flipping Y-coordinate of CAL3D/MADYMO3D relative +to the LS-DYNA model: +EQ.0: off, +EQ.1: on. +FLIPZ +Flag for flipping Z-coordinate of CAL3D/MADYMO3D relative +to the LS-DYNA model: +EQ.0: off, +EQ.1: on. +VARIABLE +DESCRIPTION +SUBCYL +CAL3D/MADYMO3D subcycling interval (# of cycles): +EQ.0: Set to 1, +GT.0: SUBCYL must be an integer equal to the number of LS- +DYNA time steps between each CAL3D/MADYMO3D +step. Then the position of the contacting rigid bodies is +assumed to be constant for n LS-DYNA time steps. This +may result in some increase in the spikes in contact, thus +this option should be used carefully. +the +CAL3D/MADYMO3D programs usually work with a +very small number of degrees of freedom, not much gain +in efficiency can be achieved. + As +*CONTROL +Purpose: Global control parameters for CPM (Corpuscular Particle Method). + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CPMOUT +NP2P +NCPMTS CPMERR +SFFDC +Type +I +Default +11 +I +5 +I +0 +I +0 +F +1.0 + VARIABLE +DESCRIPTION +CPMOUT +Control CPM output database to the d3plot files: +EQ.11: full CPM database in version 3 format (default) +EQ.21: full CPM database in version 4 format +EQ.22: CPM coordinates only in version 4 format +EQ.23: CPM summary only in version 4 format +NP2P +Number of cycles for repartition particle among processors. This +option is only used in LS-DYNA/MPP. (Default = 5) +NCPMTS +Time step size estimation: +EQ.0: not consider CPM (default) +EQ.1: use 1 micro-second as CPM time step size. This provides +a better time step size if the model is made by rigid body. +CPMERR +EQ.0: disable checking and only output warning messages +(Default) +EQ.1: enable error checking. If LS-DYNA detects any problem, +it will either error terminate the job or try to fix the prob- +lem. Activated checks include: +1. Airbag integrity +2. Chamber integrity: this step applies the airbag +integrity check to the chamber. +3. +Inconsistent orientation between the shell refer- +VARIABLE +DESCRIPTION +SFFDC +Scale factor for the force decay constant. The default value is 1 +and allowable arrange is [0.01,100]. +ence geometry and FEM shell connectivity. +Remarks: +1. D3PLOT Version. “Version 3” is an older format than “Version 4”. Version 4 +stores data more efficiently than version 3 and has options for what data is +stored, but may not be readable by old LS-PrePost executables. +2. Airbag Integrity Checking. The bag’s volume is used to evaluate all bag state +variables. If the volume is ill-defined or inaccurate, then the calculation will +fail. Therefore, it is vital that that the volume be closed, and that all shell nor- +mal vectors point in the same direction. +When CPMERR = 1 the calculation will error terminate if either the bag’s vol- +ume is not closed or if one of its parts is not internally oriented (meaning that it +contains elements that are not consistently oriented). Once it is verified that +each part has a well-defined orientation, an additional check is performed to +verify that all of bag’s constituent parts are consistently oriented with respect to +each other. If they are not, then the part orientations are flipped until the bag is +consistently oriented with an inward pointing normal vector. +3. Force Decay Constant. Particle impact force is gradually applied to airbag +segment by a special smoothing function with the following form. +𝐹apply = [1 − exp ( +−𝑑𝑡 +SFFDC× 𝜏 +)] (𝐹current + 𝐹stored) +Where τ is the force decay constant stored in LS-DYNA. +Purpose: Control CPU time. +*CONTROL + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CPUTIM +IGLST +Type +F +I + VARIABLE +DESCRIPTION +CPUTIM +Seconds of CPU time: +EQ.0.0: no CPU time limit set +GT.0.0: time limit for cumulative CPU of the entire simulation, +including all restarts. +LT.0.0: absolute value is the CPU time limit in seconds for the +first run and for each subsequent restart. +IGLST +Flag for outputting CPU and elapsed times in the “glstat” file +EQ.0: no +EQ.1: yes +Remarks: +The CPU limit is not checked until after the initialization stage of the calculation. Upon +reaching the CPU limit, the code will output a restart dump file and terminate. The +CPU limit can also be specified on the LS-DYNA execution line via “c=”. If a value is +specified on both the execution line and in the input deck, the minimum value will be +used. +*CONTROL_DEBUG +Purpose: Write supplemental information to the messag file(s). One effect of this +command is that the sequence of subroutines called during initialization and memory +allocation is printed. Aside from that, the extra information printed pertains only to a +select few features, including: +1. Spot weld connections which use *MAT_100_DA and *DEFINE_CONNEC- +TION_PROPERTIES. +2. The GISSMO damage model invoked using *MAT_ADD_EROSION. (Supple- +mental information about failed elements is written.) +*CONTROL_DISCRETE_ELEMENT +Purpose: Define global control parameters for discrete element spheres. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NDAMP +TDAMP +FRICS +FRICR +NORMK +SHEARK +CAP +VTK +Type +Default +F +0 +F +0 +F +0 +F +0 +F +F +0.01 +2/7 +I +0 +I +0 +Capillary Card. Additional card for CAP ≠ 0. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +GAMMA +VOL +ANG +GAP +NBUF +PARALLEL +Type +Default +F +0 +F +0 +F +0 +F +0 +I +6 +I +0 +Card 3 is optional. If optional Card 3 is used, then Optional Card 2 must be defined. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LNORM +LSHEAR +FRICD +DC +Type +Default +I +0 +I +0 +F +FRICS +F +0 + VARIABLE +DESCRIPTION +NDAMP +Normal damping coefficient +TDAMP +Tangential damping coefficient +r1 +r2 +X1 +X2 +Figure 12-12. Schematic representation of sphere-sphere interaction + VARIABLE +DESCRIPTION +FRICS +Static coefficient of friction +EQ.0: 3 DOF +NE.0: 6 DOF (consider rotational DOF) +FRICR +Rolling friction coefficient +NORMK +Optional: scale factor of normal spring constant. Norm contact +stiffness is calculated as 𝐾𝑛 = +(Default = 0.01) +{⎧ 𝑘1𝑟1𝑘2𝑟2 +𝑘1𝑟1+𝑘2𝑟2 +⎩{⎨ +|𝑁𝑂𝑅𝑀𝐾| 𝑖𝑓 𝑁𝑂𝑅𝑀𝐾 < 0 +𝑁𝑂𝑅𝑀𝐾 𝑖𝑓 𝑁𝑂𝑅𝑀𝐾 > 0 +SHEARK +Optional: ratio between SHEARK/NORMK (Default = 2/7). +Tangential stiffness is calculated as 𝐾𝑡 = 𝑆𝐻𝐸𝐴𝑅𝐾 ∙ 𝐾𝑛 +CAP +EQ.0: dry particles +NE.0: wet particles, consider capillary +additional input card. See Remark 1. +force and need +VTK +Output DES in VTK format for ParaView +EQ.0: no +EQ.1: yes +GAMMA +Liquid surface tension, 𝛾 +VOL +Volume fraction +VARIABLE +DESCRIPTION +ANG +GAP +Contact angle, 𝜃 +Optional parameter affecting the spatial limit of the liquid bridge. +CAP.EQ.0: GAP is ignored, if the CAP field is 0 and the +simulation is modeling dry particles. +CAP.NE.0: A liquid bridge exists when 𝛿, as illustrated in +Figure 12-13, is less or equal to min(GAP, 𝑑rup) +where 𝑑rup is the rupture distance of the bridge au- +tomatically calculated by LS-DYNA . +NBUF +GE.0: Factor of memory use for asynchronous message buffer +(Default = 6) +LT.0: Disable asynchronous scheme and use minimum +memory for data transfer +PARALLEL +EQ.0: skip contact force calculation for bonded DES (Default) +EQ.1: consider contact force calculation for bonded DES +LNORM +LSHEAR +FRICD +Load curve ID of a curve that defines function for normal stiffness +with respect to norm penetration ratio. See Remark 2. +Load curve ID of a curve that defines function for shear stiffness +with respect to norm penetration ratio. See Remark 3. +Dynamic coefficient of friction. By default, FRICD = FRICS. The +frictional coefficient is assumed to be dependent on the relative +velocity 𝑣𝑟𝑒𝑙of the two DEM in contact 𝜇𝑐 = 𝐹𝑅𝐼𝐶𝐷 + (𝐹𝑅𝐼𝐶𝑆 − +𝐹𝑅𝐼𝐶𝐷)𝑒−𝐷𝐶∙∣𝑣𝑟𝑒𝑙∣. +DC +Exponential decay coefficient. + The frictional coefficient is +assumed to be dependent on the relative velocity 𝑣𝑟𝑒𝑙of the two +DEM in contact 𝜇𝑐 = 𝐹𝑅𝐼𝐶𝐷 + (𝐹𝑅𝐼𝐶𝑆 − 𝐹𝑅𝐼𝐶𝐷)𝑒−𝐷𝐶∙∣𝑣𝑟𝑒𝑙∣. +r1 +r2 +Figure 12-13. Schematic representation of capillary force model. +Background: +This method models all parts as being comprised of rigid spheres. These sphere interact +with both conventional solids and other spheres. Sphere-sphere interactions are +modeled in contact points using springs and dampers as illustrated in Figure 12-12. +[Cundall & Strack 1979] +Remarks: +1. Capillary Forces to Model Cohesion. This extension is enabled using the +CAP field. Capillary force between wet particles is based on the following +reference. “Capillary Forces between Two Spheres with a Fixed Volume Liquid +Bridges: Theory and Experiment”, Yakov I. Rabinovich et al. Langmuir 2005, +21, 10992-10997. See Figure 12-13. +The capillary force is given by +where, +and, +𝐹 = − +2𝜋𝑅𝛾𝑐𝑜𝑠𝜃 +1 + 𝛿 +2𝑑 +, +𝑑 = +⎜⎛−1 + √1 + +2 ⎝ +2𝑉 +𝜋𝑅𝛿2 +⎟⎞, +⎠ +𝑅 = +2𝑟1𝑟2 +𝑟1 + 𝑟2 +. +2. For two interacting DEMs with user defined curve for norm stiffness y = f(x), +min (𝑟1,𝑟2) is relative penetration, and δ is penetration; the normal +where 𝑥 = +spring force is calculated as +𝐹𝑛 = 𝑘𝑒𝑓𝑓 ∙ 𝑦 ∙ 𝑚𝑖𝑛2(𝑟1, 𝑟2) + where 𝑘𝑒𝑓𝑓 is the effective bulk modulus of two interacting DEM particles +. If curve is defined as 𝑦 = 𝑐 ∙ 𝑥, the behavior is the same as +𝑘1𝑘2 +𝑘1+𝑘2 +𝑘𝑒𝑓𝑓 = +NORMK = c. +3. For two interacting DEMs with user defined curve for shear stiffness y = f(x), +where 𝑥 = +min (𝑟1,𝑟2) is relative penetration, and δ is penetration; the tangential +stiffness is calculated as 𝐾𝑠 = 𝑦 ∙ 𝐾𝑛, where 𝐾𝑛 is norm stiffness defined by +NORMK or user defined curve. If curved is defined as y = c, the behavior is the +same as SHEARK = c. +*CONTROL_DYNAMIC_RELAXATION +Purpose: Initialize stresses and deformation in a model to simulate a preload. +Examples of preload include load due to gravity, load due to a constant angular +velocity, and load due to torquing of a bolt. After the preloaded state is achieved by +one of the methods described below, the time resets to zero and the normal phase of the +solution automatically begins from the preloaded state. +IDRFLG controls the manner in which the preloaded state is computed. If IDRFLG is 1 +or -1, a transient “dynamic relaxation” analysis is invoked in which an explicit analysis, +damped by means of scaling nodal velocities by the factor DRFCTR each time step, is +performed. When the ratio of current distortional kinetic energy to peak distortional +kinetic energy (the convergence factor) falls below the convergence tolerance (DRTOL) +or when the time reaches DRTERM, the dynamic relaxation analysis stops and the +current state becomes the initial state of the subsequent normal analysis. +Distortional kinetic energy is defined as total kinetic energy less the kinetic energy due +to rigid body motion. A history of the distortional kinetic energy computed during the +dynamic relaxation phase is automatically written to a file called “relax”. This file can +be read as an ASCII file by LS-PrePost and its data plotted. The “relax” file also +includes a history of the convergence factor. +To create a binary output database having the same format as a d3plot database but +which pertains to the dynamic relaxation analysis, use *DATABASE_BINARY_D3- +DRLF. The output interval is given by this command as an integer representing the +number of convergence checks between output states. + The frequency of the +convergence checks is controlled by the parameter NRCYCK. +Dynamic relaxation will be invoked if SIDR is set to 1 or 2 in any of the *DEFINE_- +CURVE commands, even if IDRFLG = 0 in *CONTROL_DYNAMIC_RELAXATION. +Curves so tagged are applicable to the dynamic relaxation analysis phase. Curves with +SIDR set to 0 or 2 are applicable to the normal phase of the solution. Dynamic +relaxation will always be skipped if IDRFLAG is set to -999. +At the conclusion of the dynamic relaxation phase and before the start of the normal +solution phase, a binary dump file (d3dump01) and a “prescribed geometry” file +(drdisp.sif) are written by LS-DYNA. Either of these files can be used in a subsequent +analysis to quickly initialize to the preloaded state without having to repeat the +dynamic relaxation run. The binary dump file is utilized via a restart analysis . The drdisp.sif file is utilized by +setting IDRFLG=2 as described below and discussed in Remark 1. +If IDRFLG is set to 2, the preloaded state is quickly reached by linearly ramping nodal +displacements, rotations, and temperatures to prescribed values over 100 time steps, or +over a number of time steps as indicated by the variable NC. See the optional cards +pertaining to IDRFLG = 2 and also Remarks 1 and 5. +If IDRFLG is set to 5, an implicit analysis is performed to obtain the preloaded state and +in this case, the preload analysis completes when 'time' is equal to DRTERM. The +implicit step size is specified with a *CONTROL_IMPLICIT_GENERAL command. The +implicit analysis is, by default, static but can be made transient via the *CONTROL_IM- +PLICIT_DYNAMICS command . +IDRFLG = 6 also performs an implicit analysis as with IDRFLG = 5 but only for the part +subset specified with DRPSET. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NRCYCK +DRTOL +DRFCTR DRTERM +TSSFDR +IRELAL +EDTTL +IDRFLG +Type +I +F +F +F +F +I +F +Default +250 +0.001 +0.995 +infinity TSSFAC +0 +0.04 +I +0 +Remarks +3 +1, 2, 3 +Additional card for IDRFLG = 3 or 6. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DRPSET +Type +Default +Remarks +I +0 +3 +4 +5 +6 +7 +8 +Additional card for IDRFLG = 2. + Card 2 +Variable +1 +NC +Type +I +Default +100 +2 +NP +I +0 +NP Additional cards for IDRFLG = 2. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PSID +VECID +Type +Default +I +0 +I +0 + VARIABLE +NRCYCK +DESCRIPTION +Number of time steps between convergence checks for explicit +dynamic relaxation. +DRTOL +Convergence +(default = 0.001). +tolerance +for +explicit dynamic +relaxation +DRFCTR +Dynamic relaxation factor (default = .995). +DRTERM +TSSFDR +Optional termination time for dynamic relaxation. Termination +occurs at this time or when convergence is attained (de- +fault = infinity). +Scale factor for computed time step during explicit dynamic +relaxation. If zero, the value is set to TSSFAC defined on *CON- +TROL_TIMESTEP. After converging, the scale factor is reset to +TSSFAC. +VARIABLE +IRELAL +DESCRIPTION +Automatic control for dynamic relaxation option based on +algorithm of Papadrakakis [1981]: +EQ.0: not active, +EQ.1: active. +EDTTL +Convergence +relaxation. +tolerance on automatic control of dynamic +IDRFLG +Dynamic relaxation flag for stress initialization: +EQ.-999: dynamic relaxation not activated even if specified on +a load curve, see *DEFINE_CURVE. +EQ.-1: +dynamic relaxation is activated and time history +output is produced during dynamic relaxation, see +Remark 2. +EQ.0: +EQ.1: +EQ.2: +EQ.3: +EQ.5: +EQ.6 +not active, +dynamic relaxation is activated, +initialization to a prescribed geometry, see Remark 1, +dynamic relaxation is activated as with IDRFLG = 1, +but with a part set ID for convergence checking, +initialize implicitly, see Remark 3. +initialize implicity but only for the part set specified +by DRPSET. +DRPSET +Part set ID for convergence checking (for IDRFLG = 3 or 6 only) +NC +NP +Number of time steps for initializing geometry of IDRFLG = 2. +Number of part sets specified for IDRFLG = 2. +PSID +Part set ID for IDRFLG = 2. +VECID +Vector ID for defining origin and axis of rotation for IDRFLG = 2. +See Remark 5. +Remarks: +1. When IDRFLG = 2, an ASCII file specified by "m=" on the LS-DYNA execution +line is read which describes the initialized state. The ASCII file contains each +node ID with prescribed values of nodal displacement (x, y, z), nodal rotation +(x, y, z) and nodal temperature in (I8, 7E15.0) format. +2. +If IDRFLG is set to -1 the dynamic relaxation proceeds as normal but time +history data is written to the d3thdt file in addition to the normal data being +written to the d3drlf file. At the end of dynamic relaxation, the problem time is +reset to zero. However, information is written to the d3thdt file with an incre- +ment to the time value. The time increment used is reported at the end of dy- +namic relaxation. +3. When IDRFLG = 5 or 6, LS-DYNA performs an implicit analysis for the preload +phase of the simulation. Parameters for controlling the implicit preload solu- +tion are defined using appropriate *CONTROL_IMPLICIT keywords to specify +solver type, implicit time step, etc. When using this option, one must specify +DRTERM to indicate the termination "time" of the implicit preload analysis. +When DRTERM is reached, the implicit preload phase terminates and LS-DY- +NA begins the next phase of the analysis according to IMFLAG in *CON- +TROL_IMPLICIT_GENERAL. For example, if it is desired to run an implicit +preload phase and switch to the explicit solver for the subsequent transient +phase, IDRFLG should be set to 5 and IMFLAG should be set to 0. +4. When IDRFLG = 3, a part set ID is used to check for convergence. For example, +if only the tires are being inflated on a vehicle, it may be sufficient in some cases +to look at convergence based on the part ID’s in the tire and possibly the sus- +pension system. You can also use IDRFLG = 6 to perform the initialization +using implicit on the part set. +5. When the displacements for IDRFLG = 2 are associated with large rotations, the +linear interpolation of the displacement field introduces spurious compression +and tension into the part. If a part set is specified with a vector, the displace- +ment is interpolated by using polar coordinates with the tail of the vector speci- +fying the origin of the coordinate system and the direction specifying the +normal to the polar coordinate plane. +*CONTROL +Purpose: Define controls for the mesh-free computation. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ISPLINE +IDILA +ININT +Type +Default +I +0 +I +0 +Remarks + Card 2 +1 +2 +I +12 +1 +3 +4 +5 +6 +7 +8 +Variable +IMLM +ETOL +IDEB +HSORT +SSORT +Type +Default +I +0 +F +1.0E-4 +I +0 +I +0 +I +0 + VARIABLE +DESCRIPTION +ISPLINE +Optional choice for the mesh-free kernal functions: +EQ.0: Cubic spline function (default) +EQ.1: Quadratic spline function +EQ.2: Cubic spline function with circular disk +IDILA +Optional choice for the normalized dilation parameter: +EQ.0: Maximum distance based on the background element +EQ.1: Maximum distance based on surrounding nodes +ININT +This is the factor needed for the estimation of maximum +workspace (MWSPAC) that can be used during the initialization +phase. +IMLM +*CONTROL_EFG +DESCRIPTION +Optional choice for the matrix operation, linear solving and +memory usage: +EQ.1: Original BCSLIB-EXT solvers +EQ.2: EFGPACK +ETOL +Error tolerance in the IMLM. When IMLM = 2 is used, ININT in +card one becomes redundant. IMLM = 2 is recommended. +IDEB +Output internal debug message +HSORT +Not used +SSORT +Automatic sorting of background triangular shell elements to +FEM #2 when EFG shell type 41 is used +EQ.0: no sorting +EQ.1: full sorting +Remarks: +1. The mesh-free computation requires calls to use BCSLIB-EXT solvers during the +initialization phase. The maximum workspace (MWSPAC) that can be used +during the call is calculated as +MWSPAC = ININT3 × NUMNEFG, +where NUMNEFG is the total number of mesh-free nodes. ININT, which is the +number of nodes that a node influences along each cardinal direction, defaults +to 12. When the normalized dilation parameters (DX, DY, DZ) in *SECTION_- +SOLID_EFG are increased ININT must likewise increase. +2. When ISPLINE = 2 is used, the input of the normalized dilation parameters +(DX, DY, DZ) for the kernel function in *SECTION_SOILD_EFG and SECTI- +OL_SHELL_EFG only requires the DX value. +3. EFGPACK was added to automatically compute the required maximum +workspace in the initialization phase and to improve efficiency in the matrix +operations, linear solving, and memory usage. The original BCSLIB-EXT solver +requires an explicit workspace (ININT) for the initialization. +*CONTROL +Purpose: Provide controls for energy dissipation options. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +HGEN +RWEN +SLNTEN +RYLEN +Type +Default +I +1 +I +2 +I +1 +I +1 + VARIABLE +HGEN +DESCRIPTION +Hourglass energy calculation option. +significant additional storage and increases cost by ten percent: + This option requires +EQ.1: hourglass energy is not computed (default), +EQ.2: hourglass energy is computed and included in the +energy balance. The hourglass energies are reported in +files glstat and matsum, see *DATA- +the ASCII +BASE_OPTION. +RWEN +Rigidwall energy (a.k.a. stonewall energy) dissipation option: +EQ.1: energy dissipation is not computed, +EQ.2: energy dissipation is computed and included in the +energy balance (default). The rigidwall energy dissipa- +tion is reported in the ASCII file glstat, see *DATA- +BASE_OPTION. +SLNTEN +Sliding interface energy dissipation option (This parameter is +always set to 2 if contact is active. The option SLNTEN = 1 is not +available.): +EQ.1: energy dissipation is not computed, +EQ.2: energy dissipation is computed and included in the +energy balance. The sliding interface energy is reported +in ASCII +*DATA- +BASE_OPTION. +files glstat and sleout, +see +VARIABLE +DESCRIPTION +RYLEN +Rayleigh energy dissipation option (damping energy dissipation): +EQ.1: energy dissipation is not computed (default), +EQ.2: energy dissipation is computed and included in the +energy balance. The damping energy is reported in +*DATA- +ASCII +BASE_OPTION. + and matsum, +file glstat +see +*CONTROL_EXPLICIT_THERMAL +The *CONTROL_EXPLICIT_THERMAL_SOLVER keyword activates an explicit finite +volume code solving heat transfers by conduction. Enthalpies and temperatures are +element centered. The elements supported by the thermal solver are beams, shells, +The +solids, +*CONTROL_EXPLICIT_THERMAL_PROPERTIES keyword defines the heat capacities +and conductivities by parts. These 2 keywords are mandatory to properly run the +solver. Other keywords can be used to set the initial and boundary conditions and +control the outputs. They are all listed below in alphabetical order: +multi-material +elements. +ALE +3D +*CONTROL_EXPLICIT_THERMAL_ALE_COUPLING +*CONTROL_EXPLICIT_THERMAL_BOUNDARY +*CONTROL_EXPLICIT_THERMAL_CONTACT +*CONTROL_EXPLICIT_THERMAL_INITIAL +*CONTROL_EXPLICIT_THERMAL_OUTPUT +*CONTROL_EXPLICIT_THERMAL_PROPERTIES +*CONTROL_EXPLICIT_THERMAL_SOLVER +*CONTROL_EXPLICIT_THERMAL_ALE_COUPLING +Purpose: Define the shell and solid parts involved in an explicit finite volume thermal +requires +coupling with multi-material ALE +*CONSTRAINED_LAGRANGE_IN_SOLID, CTYPE = 4. +keyword +groups. + This + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PARTSET MMGSET +Type +I +I +Default +none +none + VARIABLE +DESCRIPTION +PARTSET +Part set ID +MMGSET +Multi-material +MATERIAL_GROUP_LIST) +set +ID +(see +*SET_MULTI- +Remarks: +*CONTROL_EXPLICIT_THERMAL_BOUNDARY +Purpose: Set temperature boundaries with segment sets for an explicit finite volume +thermal analysis. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SEGSET +LCID +Type +I +F +Default +none +none + VARIABLE +DESCRIPTION +SEGSET +Segment set ID +LCID +*DEFINE_CURVE ID defining the temperature in function of time +Remarks: +1. Boundary elements. The boundary temperatures are set at segment centers. If +shells or beams have all their nodes in the segment set, these elements would be +considered as boundary elements: the temperatures at their centers will be +controlled by the curve LCID. +*CONTROL_EXPLICIT_THERMAL_CONTACT +Purpose: Define the beam, shell and solid parts involved in an explicit finite volume +thermal contact. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PARTSET NCYCLE +Type +I +Default +none +F +1 + VARIABLE +DESCRIPTION +PARTSET +Part set ID +NCYCLE +Number of cycle between checks of new contact +Remarks: +*CONTROL_EXPLICIT_THERMAL_INITIAL +Purpose: Initialize the temperature centered in beams, shells or solids involved in an +explicit finite volume thermal analysis. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SET +SETYP +TEMPINI +Type +I +F +F +Default +none +none +0.0 + VARIABLE +DESCRIPTION +SET +set ID +SETYP +Type of set: +EQ.1: solid set +EQ.2: shell set +EQ.3: +TEMPINI +Initial temperature +Remarks: +1. Material with *EOS. The volumetric enthalpy is the sum of the pressure and +volumetric internal energy (as defined in *EOS). If the material has an equation +of state, the enthalpy should not be initialized by the temperature but by the +initial volumetric internal energy and pressure set in *EOS. +*CONTROL_EXPLICIT_THERMAL_OUTPUT +Purpose: Output temperatures and enthalpies for an explicit finite +volume thermal analysis. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DTOUT DTOUTYP +SET +SETYP +Type +F +Default +none +I +0 +I +0 +I +0 + VARIABLE +DESCRIPTION +DTOUT +Time interval between outputs +DTOUTYP +Type of DTOUT: +EQ.0: DTOUT is a constant +EQ.1: DTOUT is the ID of *DEFINE_CURVE defining a table of +time vs DTOUT +SET +set ID +SETYP +Type of set: +EQ.1: solid set +EQ.2: shell set +EQ.3: beam set . +2. Output by element. If a set of elements SET is defined, the temperature and +enthalpy histories are output by element in a .xy format. The file names are +and +temperature_{beam,shell,solid}ID.xy +The binary file xplcth_output is not output. +enthalpy_{beam,shell,solid}ID.xy. +*CONTROL_EXPLICIT_THERMAL_PROPERTIES +Purpose: Define the thermal properties of beam, shell and solid parts involved in an +explicit finite volume thermal analysis. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PARTSET +CP +CPTYP +VECID1 +VECID2 +LOCAL +Type +I +F +Default +none +none + Card 2 +1 +2 +I +0 +3 +I +0 +4 +I +0 +5 +I +0 +6 +Variable +Kxx +Kxy +Kxz +KxxTYP +KxyTYP +KxzTYP +Type +F +F +F +Default +0.0 +0.0 +0.0 + Card 3 +1 +2 +3 +I +0 +4 +I +0 +5 +I +0 +6 +Variable +Kyx +Kyy +Kyz +KyxTYP +KyyTYP +KyzTYP +Type +F +F +F +Default +0.0 +0.0 +0.0 +I +0 +I +0 +I +0 +7 +8 +7 +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Kzx +Kzy +Kzz +KzxTYP +KzyTYP +KzzTYP +Type +F +F +F +Default +0.0 +0.0 +0.0 +I +0 +I +0 +I +0 + VARIABLE +DESCRIPTION +PARTSET +Part set ID +CP +Heat capacity +CPTYP +Type of CP: +EQ.0: CP is a constant +VECID1, +VECID2 +EQ.1: CP is the ID of *DEFINE_CURVE defining a table of +temperature vs heat capacity +*DEFINE_VECTOR IDs to define a specific coordinate system. +VECID1 and VECID2 give the 𝑥- and 𝑦-direction respectively. +The 𝑧-vector is a cross product of VECID1 and VECID2. If this +latter is not orthogonal to VECID1, its direction will be corrected +with a cross-product of 𝑧- and 𝑥-vectors. The conductivity matrix +Kij is applied this coordinate system. +LOCAL +Flag to activate an element coordinate system: +EQ.0: The vectors VECIDj are considered in a global coordinate +system. +EQ.1: The vectors VECIDj are considered in a local system +attached to the element. For shells and solids, the system +is the same as DIREC = 1 and CTYPE = 12 in *CON- +STRAINED_LAGRANGE_IN_SOLID. For shells, the +edge centers replace the face centers. For beams, the 𝑥- +in +direction +*ELEMENT_BEAM and there should be a 3rd node for +the 𝑦-direction. +is aligned with +first 2 nodes +the +Kij +Heat conductivity matrix +VARIABLE +DESCRIPTION +KijTYP +Type of Kij: +EQ.0: Kij is a constant +EQ.1: Kij is the ID of *DEFINE_CURVE defining a table of +temperature vs heat conductivity +Remarks: +*CONTROL_EXPLICIT_THERMAL_SOLVER +Purpose: Define the beam, shell and solid parts involved in a finite volume thermal +analysis. The enthalpies and temperatures are explicitly updated in time. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PARTSET +DTFAC +Type +I +F +Default +none +1.0 + VARIABLE +DESCRIPTION +PARTSET +Part set ID +DTFAC +Time step factor +Remarks: +1. Time step. The time step is a minimum of the mechanical and thermal time +steps. The thermal time step is a minimum of the element thermal time steps, +which are half the enthalpies divided by the right hand side of the heat equa- +tion (conductivity * temperature laplacian). The thermal time step is scaled by +DTFAC (=1 by default) +*CONTROL_EXPLOSIVE_SHADOW_{OPTION} +Available option includes: + +SET +Purpose: Compute detonation times in explosive elements for which there is no direct +line of sight. If this command is not included in the input, the lighting time for an +explosive element is computed using the distance from the center of the element to the +nearest detonation point, 𝐿𝑑; the detonation velocity, 𝐷; and the lighting time for the +detonator, 𝑡𝑑: +𝑡𝐿 = 𝑡𝑑 + +𝐿𝑑 +The detonation velocity for this option is taken from the element whose lighting time is +computed and does not account for the possibilities that the detonation wave may +travel through other explosives with different detonation velocities or that the line of +sight may pass outside of the explosive material. +If this command is present, the lighting time of each explosive element is based on the +shortest path through the explosive material from the associated detonation point(s) to +the explosive element. If inert obstacles exist within the explosive material, the lighting +time will account for the extra time required for the detonation wave to travel around +the obstacles. The lighting times also automatically accounts for variations in the +detonation velocity if different explosives are used. +The SET option requires input of a set ID of two-dimensional shell elements or three- +dimensional solid elements for which explosive shadowing is active. If the SET option +is not used, Card 1 should be omitted and shadowing is active for all explosive +elements. +See also *INITIAL_DETONATION and *MAT_HIGH_EXPLOSIVE. +Card 1. Card for SET keyword option. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SETID +Type +I +Default +None + VARIABLE +SETID +DESCRIPTION +Set ID of a *SET_SHELL or *SET_SOLID. If the SET option is +active, the lighting times are computed for a set of shells +(*SET_SHELL in two dimensions) or solids (*SET_SOLID in three +dimensions). +*CONTROL_FORMING +Purpose: Set parameters for metal forming related features. +*CONTROL_FORMING_AUTOCHECK +*CONTROL_FORMING_AUTO_NET +*CONTROL_FORMING_AUTOPOSITION +*CONTROL_FORMING_BESTFIT +*CONTROL_FORMING_INITIAL_THICKNESS +*CONTROL_FORMING_MAXID +*CONTROL_FORMING_ONESTEP +*CONTROL_FORMING_OUTPUT +*CONTROL_FORMING_PARAMETER_READ +*CONTROL_FORMING_POSITION +*CONTROL_FORMING_PRE_BENDING +*CONTROL_FORMING_PROJECTION +*CONTROL_FORMING_REMOVE_ADAPTIVE_CONSTRAINTS +*CONTROL_FORMING_SCRAP_FALL +*CONTROL_FORMING_SHELL_TO_TSHELL +*CONTROL_FORMING_STONING +*CONTROL_FORMING_TEMPLATE +*CONTROL_FORMING_TIPPING +*CONTROL_FORMING_TOLERANC +*CONTROL_FORMING_TRAVEL +*CONTROL_FORMING_TRIM_MERGE +*CONTROL_FORMING_TRIMMING +*CONTROL_FORMING_UNFLANGING +*CONTROL_FORMING_USER +*CONTROL_FORMING_AUTOCHECK +Purpose: This keyword detects and corrects flaws in the mesh for the rigid body that +models the tooling. Among its diagnostics are checks for duplicated elements, +overlapping elements, skinny/long elements, degenerated elements, disconnected +elements, and inconsistent element normal vectors. +This feature also automatically orients each tool’s element normal vectors so that they +face the blank. Additionally an offset can be specified to create another tool (tool +physical offset) based on the corrected tool meshes. Note that this keyword is distinct +from *CONTROL_CHECK_SHELL, which checks and corrects mesh quality problem +after trimming, to prepare the trimmed mesh for the next stamping process. This +keyword only applies to shell elements. +The tool offset feature is now available in LS-PrePost 4.2 under Application → +MetalForming → Easy Setup. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ICHECK +IGD +IOFFSET +IOUTPUT +Type +Default +I +0 +I +none +I +0 +I +none +VARIABLE +DESCRIPTION +ICHECK +Tool mesh checking/correcting flag: +ICHECK.EQ.0: Do not activate mesh checking/correcting +feature. +ICHECK.EQ.1: Activate comprehensive mesh check and correct +problematic tool meshes . +This option reduces the likelihood of unreason- +able forming results and/or error termination. +This is only for regular forming simulations. +The calculation will continue after the tool mesh +checking/correcting phase is completed. See +Example 1. +The corrected tool meshes can be viewed and +recovered from the resulting d3plot files. If the +termination time is set to “0.0” or the keyword +*CONTROL_TERMINATION is absent all to- +gether, the simulation will terminate as soon as +checking/correcting is completed, and correct- +ed tool meshes can be extracted from the d3plot +files. +IGD +Not used. +IOFFSET +Tool mesh offset flag. This variable works only when IOUTPUT +is defined, and ICHECK is set to “1”: +IOFFSET.EQ.0: Do not offset rigid tool mesh. The sheet blank +does not need to be present. In this case the +output files rigid_offset.inc and rigid_offset_ +before.inc will be identical. See Example 2. +IOFFSET.EQ.1: Perform rigid tool mesh offset using the +variable MST as specified on +a *CONTACT_FORMING_… card. The blank +must be defined and positioned completely +above or below the rigid tool to be offset. Both +part ID and part SID (MSTYP) can be used in +defining the MSID. IOUTPUT must also be de- +fined. +VARIABLE +DESCRIPTION +IOUTPUT +Output option flag: +IOUTPUT.EQ.1: Output offset rigid tool meshes into a keyword +file rigid_offset.inc, and terminates the simula- +tion. +IOUTPUT.EQ.2: Output offset rigid tool meshes as well as +nodes used to define draw beads into a key- +word file rigid_offset.inc, and terminates the +simulation. See Example 4. +IOUTPUT.EQ.3: Output checked/corrected tool as well as +offset rigid tool meshes into two separate key- +word files, rigid_offset_before.inc, and rigid_ +offset.inc, respectively, and terminates the +simulation. See Example 3. +IOUTPUT.EQ.4: Output checked/corrected tool meshes, offset +rigid tool meshes as well as the nodes used to +define draw beads into two separate keyword +rigid_ +files, +offset.inc, respectively, and terminates the +simulation. +rigid_offset_before.inc, +and +Remarks: +In sheet metal forming, tools are typically modelled as rigid bodies and their meshes are +prepared from CAD (IGES or STEP) files according to the following procedure: +1. The user imports the CAD data into a preprocessor, such as LS-PrePost. +2. The preprocessor automatically generates a mesh. LS-PrePost features a +streamlined GUI for this application. +3. Export the generated mesh to LS-DYNA input files. The LS-PrePost eZ-Setup +user interface provides quick access to generate the necessary input files for +metal forming applications. +Ideally, this process should produce a good mesh requiring no manual intervention. +Often, though, such meshes that have been automatically generated from CAD data +have flaws severe enough to prevent an accurate or complete calculation. This feature, +*CONTROL_FORMING_AUTOCHECK is intended to make LS-DYNA more robust +with respect to tooling mesh quality. +This keyword requires that the tooling meshes represent rigid bodies. Also, when this +keyword is used, a part ID or a part set ID, corresponding to MSTYP = 2 or 3 on the +*CONTACT_FORMING_… card, may be used to define the master side, MSID. +Segment set ID input, MSTYP = 0, is not supported. +Some cases of incoming bad tooling meshes which can be corrected by this keyword are +shown in Figure 12-15. This keyword can be inserted anywhere in the input deck. To +include the corrected tooling mesh into the d3plot the ICHECK field must be defined. +The corrected mesh is written to rigid_offset_before.inc file if IOFFSET and IOUTPUT +are defined. +When IOFFSET = 1 and IOUTPUT is defined, the tool meshes will first be checked, +corrected, and reoriented correctly towards the blank. Then the tool is offset by an +amount of 0.5|MST| either on the same or opposite side of the blank, depending on the +signs of the MST field on the *CONTACT_FORMING_… card (Figure 12-14). A new +keyword file, “rigid_offset.inc” file, will be output as containing the corrected, +reoriented, and offset tooling mesh. +The tool offset feature is now available in LS-PrePost 4.2 under Application → +MetalForming → Easy Setup. The offset from Die button under Binder can be used to +create offset tools. +Note this keyword does not work with the SMOOTH option in *CONTACT_FORM- +ING_… prior to Revision 95456, see Revision information. +Example 1 - Mesh checking/correction in a regular forming simulation: +The keyword can be inserted anywhere in a regular forming simulation input deck. A +partial input example of checking, correcting the tool meshes and reorienting all tools’ +normals is provided below. Note that although MST is defined between blank and die +contact interface, die meshes will not be offset, since IOFFSET is not defined. +Simulation will continue if “&endtime” is not zero, but will terminate as soon as the +checking and correcting are done if “&endtime” is set to “0.0”, or *CONTROL_TERMI- +NATION is absent all together. Corrected and reoriented tool meshes can be viewed +and recovered from d3plot files. +*KEYWORD +*INCLUDE +Tool_blank.k +*CONTROL_FORMING_AUTOCHECK +$ ICHECK IGD IOFFSET IOUTOUT + 1 +*CONTROL_TERMINATION +&endtime +⋮ +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE_ID + 1 blank to punch + 1 2 2 2 1 1 + 0.110E+00 0.000E+00 0.000E+00 0.000E+00 0.200E+02 0.0000E+00 0.100E+21 +0.000 0.000 0.0 +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE_ID + 2 blank to die +$ SSID MSID SSTYP MSTYP SBOXID MBOXID SPR MPR + 1 3 2 2 1 1 +$ FS FD DC VC VDC PENCHK BT DT + 0.110E+00 0.000E+00 0.000E+00 0.000E+00 0.200E+02 0.000E+00 0.100E+21 +$ SFS SFM SST MST SFST SFMT FSF VSF + 0.000 0.000 -1.600 +$ SOFT SOFSCL LCIDAB MAXPAR PENTOL DEPTH BSORT FRCFRQ + 0 +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE_ID + 3 blank to binder + 1 4 2 2 1 1 + 0.110E+00 0.000E+00 0.000E+00 0.000E+00 0.200E+02 0.000E+00 0.100E+21 + 0.000 0.000 0.0 +⋮ +*END +Example 2 - Mesh checking/correction only for rigid tool mesh (sheet blank not +required): +A much shorter but complete input example of checking, correcting the tool meshes and +reorienting all tools’ normals is shown below. Note the sheet blank does not need to be +present, and both rigid_offset.inc and rigid_offset_before.inc will be the same, +representing the checked, corrected, and reoriented tool mesh file, since IOFFSET is +undefined (no tool offset will be done). +*KEYWORD +*INCLUDE +toolmesh.k +*CONTROL_FORMING_AUTOCHECK +$ ICHECK IGD IOFFSET IOUTOUT + 1 1 +*PARAMETER_EXPRESSION +I toolpid 3 +*PART +$ PID SECID MID EOSID HGID GRAV ADPOPT TMID + &toolpid 2 2 +*MAT_RIGID +$ MID RO E PR N COUPLE M ALIAS + 2 7.83E-09 2.07E+05 0.28 +$ CMO CON1 CON2 + 1 4 7 +$LCO or A1 A2 A3 V1 V2 V3 +*SECTION_SHELL +$ SECID ELFORM SHRF NIP PROPT QR/IRID ICOMP SETYP + 2 2 1.0 3.0 0.0 +$ T1 T2 T3 T4 NLOC + 1.0 1.0 1.0 1.0 +*END +Example 3 - Mesh checking/correction and tool offset (sheet blank required): +In addition to checking, correcting and reorienting all tools’ normal, the following +partial input will offset the die meshes in toolmesh.k by 0.88 mm (using the MST value +defined for the die) on the opposite side of the blank, and output the offset tool meshes +in a file rigid_offset.inc. The checked/corrected original die meshes will be written to +rigid_offset_before.inc. The simulation will terminate as soon as the files are written, +regardless of what the “&endtime” value is. In fact, the keyword *CONTROL_TERMI- +NATION can be omitted all together. +*KEYWORD +*INCLUDE +Tool_blank.k +*PARAMETER_EXPRESSION +R blankt 0.8 +R offset -1.1 +R mst blankt*offset*2.0 +*CONTROL_FORMING_AUTOCHECK +$ ICHECK IGD IOFFSET IOUTOUT + 1 1 3 +*CONTROL_TERMINATION +&endtime +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE_ID + 1 blank to punch + 1 2 2 2 1 1 + 0.110E+00 0.000E+00 0.000E+00 0.000E+00 0.200E+02 0.0000E+00 0.100E+21 + 0.000 0.000 0.0 +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE_ID + 2 blank to die +$ SSID MSID SSTYP MSTYP SBOXID MBOXID SPR MPR + 1 3 2 2 1 1 +$ FS FD DC VC VDC PENCHK BT DT + 0.110E+00 0.000E+00 0.000E+00 0.000E+00 0.200E+02 0.000E+00 0.100E+21 +$ SFS SFM SST MST SFST SFMT FSF VSF + 0.000 0.000 &mst +$ SOFT SOFSCL LCIDAB MAXPAR PENTOL DEPTH BSORT FRCFRQ + 0 +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE_ID + 3 blank to binder + 1 4 2 2 1 1 + 0.110E+00 0.000E+00 0.000E+00 0.000E+00 0.200E+02 0.000E+00 0.100E+21 + 0.000 0.000 0.0 +*END +Example 4 - Mesh checking/correction and tool offset, bead nodes output (sheet +blank required): +In addition to checking, correcting and reorienting all tools’ normal, the following +partial input will create an offset tool in the file rigid_offset.inc on the same side of the +blank; the file will also contain the nodes used to define the contact draw beads #1 and +#2. +*KEYWORD +*INCLUDE +Tool_blank.k +R blankt 0.8 +R offset 1.1 +R mst blankt*offset*2.0 +*CONTROL_FORMING_AUTOCHECK +$ ICHECK IGD IOFFSET IOUTOUT + 1 1 2 +*CONTROL_TERMINATION +&endtime +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE_ID + 1 blank to punch + 1 2 2 2 1 1 + 0.110E+00 0.000E+00 0.000E+00 0.000E+00 0.200E+02 0.0000E+00 0.100E+21 + 0.000 0.000 0.0 +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE_ID + 2 blank to die +$ SSID MSID SSTYP MSTYP SBOXID MBOXID SPR MPR + 1 3 2 2 1 1 +$ FS FD DC VC VDC PENCHK BT DT + 0.110E+00 0.000E+00 0.000E+00 0.000E+00 0.200E+02 0.000E+00 0.100E+21 +$ SFS SFM SST MST SFST SFMT FSF VSF + 0.000 0.000 &mst +$ SOFT SOFSCL LCIDAB MAXPAR PENTOL DEPTH BSORT FRCFRQ + 0 +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE_ID + 3 blank to binder + 1 4 2 2 1 1 + 0.110E+00 0.000E+00 0.000E+00 0.000E+00 0.200E+02 0.000E+00 0.100E+21 + 0.000 0.000 0.0 +⋮ +*CONTACT_DRAWBEAD_ID + 10001 Draw bead #1 + 1 1 4 2 0 0 0 + 0.110E+00 0.000E+00 0.000E+00 0.000E+00 0.200E+00 0.0615 0.100E+21 + 0.200 0.200 +$ LCIDRF LCIDNF DBDTH DFSCL NUMINT + 10 9 0.100E+02 0.700E+00 +*CONSTRAINED_EXTRA_NODES_SET + 40 1 +*SET_NODE_LIST + 1 + 915110 915111 915112 915113 915114 915115 915116 915117 + 915118 915119 915120 915121 915122 +*CONTACT_DRAWBEAD_ID + 10002 Draw bead #2 + 2 1 4 2 0 0 0 + 0.110E+00 0.000E+00 0.000E+00 0.000E+00 0.200E+00 0.0615 0.100E+21 + 0.200 0.200 +$ LCIDRF LCIDNF DBDTH DFSCL NUMINT + 11 9 0.100E+02 0.400E+00 +*CONSTRAINED_EXTRA_NODES_SET +$ PID NSID + 40 2 +*SET_NODE_LIST + 2 + 915123 915124 915125 915126 915127 915128 915129 915130 + 915131 915132 915133 915134 915135 915136 915137 +⋮ +*END +Revision information: +This feature is available starting from LS-DYNA Revision 91737, in both SMP, MPP and +double precision. +1. +2. +IOFFSET, and IOUTPUT = 1 are available starting in Revision 94521. The latest +beta revisions should offer better and improved offset meshes. +IOUTPUT = 2 is available starting in Revision 95357. +3. Support of SMOOTH contact option in *CONTACT_FORMING...: is available +starting in Revision 95456. +4. +IOUTPUT = 3, and 4 are available starting in Revision 96592. +Sheet metal blank must be positioned +completely above or below the original tool +Original tool (corrected original +tool in rigid_offset_before.inc) +A negative MST result in a new +tool with normal offset distance +|(0.5)MST| from the original tool, +on the opposite side of the blank +Offset tool (rigid_offset.inc) +Sheet metal blank must be positioned +completely above or below the original tool +Offset tool (rigid_offset.inc) +A positive MST result in a new +tool with normal offset distance +|(0.5)MST| from the original tool, +on the same side of the blank +Original tool (corrected original +tool in rigid_offset_before.inc) +Figure 12-14. Offset using the MST value defined in *CONTACT_- +FORMING_… +All nodes of two +duplicate traingle +shells 21304, 34630 lie +in one straight line +Shell 34608 overlaps +with three other +triangle shells +Overlapping +shell 34604 +Overlapping +shell 34607 +A severe, multiple overlapping case +A case of typical incoming, inconsistent shell normals +Figure 12-15. A few cases of the tooling mesh problems handled by this +keyword. +*CONTROL_FORMING_AUTO_NET +Purpose: This keyword is used for simulating springback when the stamping panel is +resting on the nets of a checking fixture. With this keyword, rectangular nets are +automatically generated according to specified dimensions and positions. +Include one pair of Cards 1 and 2 per net. Add to the deck as many pairs of cards as +needed. This section is terminated by the next keyword (“*”) card. In general, for N +nets add 2N cards. +4 +IDP +I +0 +4 +8 +5 +X +F +6 +Y +F +7 +Z +F +0.0 +0.0 +0.0 +5 +6 +7 +8 + Card 1 +1 +2 +3 +Variable +IDNET +ITYPE +IDV +Type +I +Default +none + Card 2 +Variable +1 +SX +Type +F +2 +SY +F +I +0 +3 +OFFSET +F +Default +0.0 +0.0 +0.0 +VARIABLE +DESCRIPTION +IDNET +ID of the net; must be unique. +ITYPE +Not used at this time. +IDV +Vector ID for surface normal of the net. See *DEFINE_VECTOR. +If not defined, the normal vector will default to the global z-axis. +IDP +Part ID of the panel undergoing springback simulation. +X +Y +The x-coordinate of a reference point for the net to be generated. +The y-coordinate of a reference point for the net to be generated. +VARIABLE +DESCRIPTION +Z +SX +SY +The z-coordinate of a reference point for the net to be generated. +Length of the net along the first tangential direction. (The x-axis +when the normal is aligned along the global z-axis). +Length of the net along the second tangential direction. (The y- +axis when the normal is aligned along the global z-axis). +OFFSET +The net center will be offset a distance of OFFSET in the direction +of its surface normal. For positive values, the offset is parallel to +the normal; for negative values, antiparallel. +General remarks: +1. The IDNET field of card 1 sets the “net ID,” which is distinct from the part ID of +the net; the net ID serves distinguishes this net from other nets. +2. The part ID assigned to the net is generated by incrementing the largest part ID +value in the model. +3. Other properties such as section, material, and contact interfaces between the +panel and nets are likewise automatically generated. +4. The auto nets use contact type *CONTACT_FORMING_ONE_WAY_SUR- +FACE_TO_SURFACE. +An example: +The excerpted input file specifies four auto nets having IDs 1 through 4. +The vector with ID = 89 is normal to the net. The nets are offset 4 mm below their +reference points; the direction is below because the normal vector (ID = 89) is parallel to +the z-axis and the offset is negative. This example input can be readily adapted to a +typical gravity-loaded springback simulation obviating the need for SPC constraints +. +*CONTROL_FORMING_AUTO_NET +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +$ IDNET ITYPE IDV IDP X Y Z + 1 89 5 2209.82 -33.6332 1782.48 +$ SX SY OFFSET + 15.0 15.0 -4.0 +$ IDNET ITYPE IDV IDP X Y Z + 2 89 5 3060.23 -33.6335 1782.48 +$ SX SY OFFSET + 15.0 15.0 -4.0 +$ IDNET ITYPE IDV IDP X Y Z + 3 89 5 3061.21 31.4167 1784.87 +$ SX SY OFFSET +Nets automatically +generated +Two specified +coordinate locations +Trimmed panel +Figure 12-16. An example problem. + 15.0 15.0 -4.0 +$ IDNET ITYPE IDV IDP X Y Z + 4 89 5 2208.84 31.4114 1784.87 +$ SX SY OFFSET + 15.0 15.0 -4.0 +*DEFINE_VECTOR +$ VID, Tail X, Y, Z, Head X, Y, Z +89,0.0,0.0,0.0,0.0,0.0,100.0 +Discussion of Figures: +Figure 12-16 shows a formed and trimmed panel of a hat-shaped channel with an auto +net at two corners. The nets are offset 4mm away from the panel. When gravity +loading is downward the nets must be below the panel (Figure 12-17 left) so that the +panel comes into contact with the nets after springback as expected (Figure 12-17 right). +As shown in Figure 12-18 the situation must be reversed when gravity loading points +upward. +Revision information: +This feature is now available starting in implicit static in double precision LS-DYNA +Revision 62781. +Initial OFFSET 4mm +with gravity load down +Before springback +After springback +Figure 12-17. Springback and contact with nets - gravity down. +Initial OFFSET 4mm +with gravity load up +Before springback +After springback +Figure 12-18. Springback and contact with nets – gravity up. +*CONTROL_FORMING_AUTOPOSITION_PARAMETER_{OPTION} +Available options include: + +SET +Purpose: The purpose of this keyword is to calculate the minimum required separation +distances among forming tools for initial tool and blank positioning in metal forming +simulation. It is applicable to shell elements only. It does not, actually, move the part; +for that, see *PART_MOVE. +NOTE: This keyword requires that model begin in its home +position. While processing this card, LS-DYNA +moves the parts to match the auto-position results so +that auto-position operations correctly compose. +Upon completion of the auto-positioning phase, the +parts are returned to their home positions. +Auto-Position Part Cards. Add one card for each part to be auto-positioned. The +next keyword (“*”) card terminates this is keyword. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID +CID +DIR +MPID +POSITION PREMOVE +THICK +PORDER +Type +I +Default +none +I +0 +I +I +none +none +I +0 +F +F +I/A +0.0 +0.0 +none + VARIABLE +PID +DESCRIPTION +Part ID. This part will be moved based on the following +controlling parameters. +When the option SET is activated, PID becomes part set ID, +defined by *SET_PART_LIST. This is useful in defining tailor- +welded blanks, where two pieces of the blank must be moved +simultaneously. +CID +Coordinate ID (Default is global coordinate system). +VARIABLE +DESCRIPTION +DIR +Direction in which the part will be moved: +EQ.1: x direction, +EQ.2: y direction, +EQ.3: z direction. +MPID +Master part ID, whose position is to be referenced by PID for +positioning. When the option SET is activated, MPID becomes +part set ID, defined by *SET_PART_LIST. +POSITION +Definition of relative position between PID and MPID: +EQ.1: PID is above MPID; +EQ.-1: PID is below MPID. +Definition of “above” is determined by the defined coordinate +system. If PID is above MPID, it means PID has a larger z- +coordinate. This definition is helpful in line die simulation where +local coordinate system may be used. +Move PID through distance PREMOVE prior to processing the +other *CONTROL_FORMING_AUTOPOSITION cards. + See +Remark 5. +Thickness of the blank. The same value must be used in all +defined move operations under this keyword. +The name of the parameter without the ampersand “&”, as +defined in *PARAMETER, or the position or order of the +parameter defined in the *PARAMETER list. +PREMOVE +THICK +PORDER +Background: +In line-die (multi-stage) simulation, initial positioning of the tools and blank is one of +the major issues preventing several die processes from being run automatically from a +single job submission. The most basic method for running a line die simulation is to +chain a series of calculations together using the previous calculation’s partially formed +blank, written to a dynain file, as a part of the input for the next calculation. +Since the partial results are not known until the preceding calculation completes, the +tools need to reposition before the next calculation. Without this card the repositioning +step must be done by-hand using a preprocessor. With the combination of this card and +the LS-DYNA case driver the repositioning can be fully automated, +enabling a complete line-die simulation to be completed with a single job submission. +*CONTROL_FORMING_AUTOPOSITION_PARAMETER +This card requires that all parts start in their home (tool closed) position. It calculates +how far the parts need to be moved to prevent initial penetration. The results are stored +into the parameter listed in the PORDER field to be used for a part move operation. +1. For each defined move operation a *PARAMETER card must initialize the +parameter referred to in the PORDER field. +2. All tools must start in home position including desired final gaps. +3. The required distance between each contact pair is calculated and stored in the +initialized parameter named in the PORDER field. +4. The parts are repositioned through a distance based on the value written to the +parameter PORDER using the *PART_MOVE card. +5. The *PARAMETER_EXPRESSION can be used to evaluate expressions +depending on the move distances, such as times and tool move speeds. +6. The *CASE feature, is used to chain together the sub-processes in the line-dime +simulation. +Remarks: +1. Order Dependence. Input associated with this keyword is order sensitive. +The following order should be observed: +a) All model information including all elements and node +b) Part definitions +c) Part set definitions +d) *PARAMETER initialization +e) This keyword +f) *PARAMETER_EXPRESSION +g) *PART_MOVE +2. This keyword can also be used to generate a new keyword input (dynain) +containing the fully positioned model (without actually running the entire +simulation). This procedure is identical to a full calculation except that the *PA- +RAMETER_EXPRESSION keyword, the *CONTROL_TERMINATION key- +word, and tool kinematic definitions are omitted. +3. When working in local coordinate systems it is often the case that the sign of +the computed parameter may not correspond to its intended use. In this case, +the absolute value function, ABS, for the *PARAMETER_EXPRESSION key- +word is especially useful. +4. Draw beads can be modeled with beam elements that are positioned and +attached to a tool at home position. Draw beads with beam elements can also +be moved in the keyword *PART_MOVE, and automatically positioned just like +any other types of elements. +5. Cards with the PREMOVE field set are processed before all other *CONTROL_- +FORMING_AUTOPOSITON cards, regardless of their location in the input +deck. The PREMOVE field serves to modify the initial state on which the calcu- +lations of the other AUTOPOSITON cards are based. +For instance, when a binder is moved downward with the PREMOVE feature, it +will be in its post-PREMOVE position for all other AUTOPOSITION calcula- +tions. But, as is the case with the other AUTOPOSITON cards, the model will +be returned to its home position upon completion of the AUTOPOSITION +phase. Note that the master part, MPID, and the POSITION fields are ignored +when the PREMOVE field is set, and that the PREMOVE value is copied into +the PORDER parameter. +6. This feature is implemented in LS-PrePost4.0 eZSetup (http://ftp.lstc.com/- +anonymous/ outgoing/lsprepost/4.0/metalforming/) for metal forming in +both explicit and implicit application. +Part set 2 +(lower binder) +Part set 1 +(blank) +Part set 3 +(upper die) +Binder PREMOVE +(183.0 mm) +Initial position +(tools home) +Final position +(after auto-position) +Figure 12-19. An example of using the variable PREMOVE +Example 1: +An air draw process like the one shown in Figure 12-19 provides a clear illustration of +how this card, and, in particular, the PREMOVE field is used to specify the lower +binder’s travel distance. +1. The card with the PREMOVE field set, the third AUTOPOSITON card, is +processed first. It moves lower binder 183 mm upward from its home position, +and it will form the base configuration for other AUTOPOSITION cards. It will +also store this move into &bindmv. Note that although the POSITION and +MPID fields are set, they are ignored. +2. The first autoposition card, which will be the second one processed, calculates +the minimum offset distance (&blankmv) necessary for the blank (part set 1) to +clear part set 9999, which consists of the lower binder (PID = 2), which is in its +post-PREMOVE location, and of the lower punch (PID = &lpunid). +3. The next card determines the minimum offset (&updiemv) necessary to bring +the upper die (part set 3) as close to the blank as possible without penetrating. +This calculation proceeds under the assumption that the blank part set has been moved +through &blankmv. +*SET_PART_LIST +9999 +&lpunpid,2 +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*CONTROL_FORMING_AUTOPOSITION_PARAMETER_SET +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +$ PID CID DIR MPID POSITION PREMOVE THICK PORDER +$ blank move + 1 3 9999 1 &bthick blankmv +$ upper die move + 3 3 1 1 &bthick updiemv +$ lower binder move + 2 3 1 -1 183.0 &bthick bindmv +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*PART_MOVE +$ SID XMOV YMOV ZMOV CID IFSET +$ blank move + 1 0.0 0.0 &blankmv 1 +$ upper die move + 3 0.0 0.0 &updiemv 1 +$ lower binder move + 2 0.0 0.0 &bindmv 1 +The following examples demonstrates the *PARAMETER_EXPRESSION card, which is +used to derive new parameters from the value calculated during auto-positioning. In +this example, the auto-positioned distance for binder, which is stored in the parameter, +&bindmv, is used to define an additional parameter, +&bindmv1 = &bindmv − 30 mm +The *PART_MOVE step uses &bindmv1 rather than &bindmv, to move both the lower +binder and the draw beads. +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*CONTROL_FORMING_AUTOPOSION_PARAMETER_SET +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +$ PID CID DIR MPID POSITION PREMOVE THICK PORDER +$ blank move + &blksid 3 9999 1 &bthick blankmv +$ upper die move + &udiesid 3 &blksid 1 &bthick updiemv +$ lower binder move + &bindsid 3 &blksid -1 &bthick bindmv +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*PARAMETER_EXPRESSION +bindmv1 bindmv-30.0 +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*PART_MOVE +$ SID XMOV YMOV ZMOV CID IFSET +$ blank move + &blksid 0.0 0.0 &blankmv 1 +$ upper die move +&udiesid 0.0 0.0 &updiemv 1 +$ lower binder move +&bindsid 0.0 0.0 &bindmv1 1 +$ draw beads move + 909 0.0 0.0 &bindmv1 1 +Part set 2 +(upper die) +Part set 1 +(blank) +&updiemv +&updiemv +&blankmv +&blankmv +Part set 3 +(lower binder) +Figure 12-20. An example of binder closing in air draw +Example 2: +Figure 12-20 schematically shows the binder closing in the global Z-direction. A partial +keyword details follow. +*INCLUDE +$blank from previous case +case5.dynain +*INCLUDE +closing_tool.k +*INCLUDE +beads_home.k +*SET_PART_LIST +$ blank +1 +1 +*SET_PART_LIST +$ upper die +2 +2 +*SET_PART_LIST +$ lower binder +3 +3 +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*parameter +$$$$$$$$$$$$$$$$$$$$$$$$$$ Tool move variables +R blankmv 0.0 +R updiemv 0.0 +R bindmv 0.0 +$$$$$$$$$$$$$$$$$$$$$$$$$$ Tool speed and ramp up definition +R tclsup 0.001 +R vcls 1000.0 +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*CONTROL_FORMING_AUTOPOSION_PARAMETER_SET +$ PID CID DIR MPID POSITION PREMOVE THICK PORDER +$ positioning blank on top of lower binder + 1 3 3 1 0.7 blankmv +$ positioning upper die on top of blank + 2 3 1 1 0.7 updiemv +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*PARAMETER_EXPRESSION +$ PRMR1 EXPRESSION +R clstime (abs(updiemv)-vcls*tclsup)/vcls+2.0*tclsup +R endtime &clstime +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*PART_MOVE +$ PID XMOV YMOV ZMOV CID +1 0.0 0.0 &blankmv + 2 0.0 0.0 &updiemv +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*CONTROL_TERMINATION +&endtime +Revision information: +This feature is available starting in LS-DYNA Revision 56080 in both explicit and +implicit, SMP and MPP versions. Later revisions are also available with various +improvements. +*CONTROL_FORMING_BESTFIT +Available options include: + +VECTOR +Purpose: This keyword rigidly moves a part to the target so that they maximally +coincide. This feature can be used in sheet metal forming to translate and rotate a +spring back part (source) to a scanned part (target) to assess spring back prediction +accuracy. This keyword applies to shell elements only. The VECTOR option allows +vector components of the normal distance from the target to the part node to be +included +keyword +under +*NODE_TO_TARGET_VECTOR . +bestfit.out +output +the +the +file +in +This feature is available now in LS-PrePost 4.3 in Metal Forming Application/eZ Setup +(http://ftp.lstc.com/anonymous/outgoing/lsprepost/4.3/win64/). + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IFIT +NSKIP +GAPONLY +IFAST +IFSET +NSETS +NSETT +Type +Default +I +0 +I +-3 + Card 2 +1 +2 +I +0 +3 +Variable +Type +Default +I +1 +4 +I +0 +5 +FILENAME +A80 +none +I +I +none +none +6 +7 +8 + VARIABLE +DESCRIPTION +IFIT +Best fit program activation flag: +IFIT.EQ.0: do not perform best-fit. +IFIT.EQ.1: activate the best-fit program. +VARIABLE +NSKIP +DESCRIPTION +Optional skipping scheme during bucket searching to aid the +computational speed (zero is no skipping): +NSKIP.GT.0: Number of nodes to skip in bucket searching. +NSKIP of “1” does not skip any nodes in search- +ing therefore computing speed is the slowest but +accuracy is the highest. Higher values of NSKIP +speed up the calculation time with slightly dete- +riorating accuracies. Based on studies, a value of +“5” is recommended with IFAST = 1, which bal- +ances the speed and accuracy. See Table 12-21 for +the effect of NSKIP on the accuracy of the fitting. +NSKIP.LT.0: Absolute value is the distance to skip in bucket +searching. This scheme is faster compared to the +previous method and therefore is recommended +for computational efficiency and accuracy. A +value of “-5” is suggested. See Example 3. +IFAST = 0 +IFAST = 1 +NSKIP + CPU time +2 +5 +10 +20 +50 +10 min 38 sec +4 min 49 sec +2 min 46 sec +1 min 24 sec +50 sec +Max/Min +(mm) +1.28/-1.59 +1.21/-1.59 +1.27/-1.59 +1.27/-1.59 +1.22/-1.61 + CPU time +4 min 3 sec +1 min 59 sec +1 min 18 sec +59 sec +40 sec +Max/Min +(mm) +1.22/-1.59 +1.25/-1.61 +1.44/-1.53 +1.42/-1.64 +1.43/-1.67 +Table 12-21. Computing speed and the max/min deviations from the +springback mesh to the target scan for an automotive part, under various +combinations of NSKIP and IFAST. All runs were made on a 1 CPU XEON +E5520 machine, with 685132 elements on the target scan and 135635 elements +on the springback mesh. + VARIABLE +DESCRIPTION +GAPONLY +Separation distance calculation flag: +GAPONLY.EQ.0: perform +best-fit, +separation +distances between the two best-fitted mesh +parts. +calculate +GAPONLY.EQ.1: no best-fit, just calculate separation distances +between the two existing mesh parts. +GAPONLY.EQ.2: User is responsible to move the parts closer in +distance and orientation, in situation where +target and source are not similar in shape. +Also see NSETS and NSETT (recommended +method). +IFAST +Computing performance optimization flag: +IFSET +IFAST.EQ.0: no computing speed optimization. +IFAST.EQ.1: activate computing speed optimization (default), +and is recommended. +See Table 12-21 for detailed speed performance data. +Optional flag to define a node set to be included or excluded in +the source mesh file for best fitting. The node set can be defined +in a file together with the source mesh. A node set can be defined +using LS-PrePost via menu options Model→CreEnt→Set +Data→*SET_NODE→Cre. +IFSET.EQ.0: all nodes in the source mesh file will be best fitted. +IFSET.GT.0: the input value is a node set ID; only the nodes in +VARIABLE +DESCRIPTION +the set will be best fitted. +IFSET.LT.0: the absolute value is a node set ID; all nodes +excluding those in the set will be best fitted. See +Example 2. +An optional node set ID of three nodes from the source mesh. +The nodes should be selected based on distinctive geometry +features, such as, the center of an arc, the center of a dart, or the +end node of a take-up bead . +The three nodes must not be aligned in one straight line. Define +NSETS if the orientation of the source mesh deviates from the +target is large (>~30 degrees in any direction). This is the +recommended method. +An optional node set ID from the target mesh, consists of the +corresponding three nodes from the same geometry features of +the source mesh. The three nodes should be input in the same +order as those from the source mesh. Approximate locations are +acceptable. Define NSETT only if NSETS is defined. See Example +3 and Figure 12-22 for details. This is the recommended method. +Target mesh file in keyword format, where only *NODE and *EL- +EMENT_SHELL should be included. The target mesh is typically +the scanned part converted from the STL format file. STL file +format can be imported into LS-PrePost via File→Import→STL File, +then a keyword format mesh file can be saved. +NSETS +NSETT +FILENAME +Remarks: +In springback prediction and compensation process simulation, there is always a need +to assess the accuracy of the springback prediction using physical white-light scanned +parts. Scanned parts are typically given in the STL format, which can be imported into +LS-PrePost and written back out as a keyword mesh file. +The converted scanned keyword file can be used as FILENAME as a target mesh in an +input file . The predicted springback mesh (source), consisting of +*NODE, *ELEMENT_SHELL, *CONSTRAIN_ADAPTIVITY cards only, can be included +in the input file using *INCLUDE. The best-fit program uses an iterative least-squares +method to minimize the separation distances between the two parts, eventually +transforming the springback mesh (source) into the position of the target mesh (scan). +The normal distances between the two parts are calculated after the best-fitting, and +stored as thickness values in a file bestfit.out, which is essentially a dynain file. +Both positive and negative distances are calculated and stored as the Thickness. Color +contours of the normal distances between the two parts can then be plotted using +COMP→Thickness. Positive distance means the source mesh is above the target mesh in +a larger coordinates, and negative distance is below the target mesh in a smaller +coordinates. For areas where no corresponding meshes can be found between the two +parts, the distances are set to nearly zero. The fitting accuracy is within 0.02mm. +To reduce the computing time , the scan file (STL) mesh can be coarsened in a scan- +processing software from a typically very dense mesh to a more reasonably sized mesh. +In any case, the coarser mesh should be selected as the target mesh for optimal +computational speed. +The fitted mesh bestfit.out and target mesh parts can both be imported into LS-PrePost. +Using the SPLANE feature in LS-PrePost, multiple sections can be cut on both parts to +assess springback deviations on a cut-section basis. +It is suggested that the orientation of the included file (source) should be within 30 +degrees in any direction of the target file. In addition, the more rotations needed to re- +orient the include file to align with the target file, the more CPU time will it take to +complete the best fitting. +In case the source mesh orients more than 30 degrees in any directions of the target +mesh, NSETS and NSETT can be used to initially align the source mesh to the target +mesh before a full best-fit is performed. See Example 3 and Figure 12-22. +Example 1 – fitting with all nodes from the included file: +A complete input example is provided below to best fit a source mesh part spbk_ +NoSS.k to the target mesh part scan.k. NSKIP is set to “-5” and speed optimization is +activated by setting IFAST to “1”. +*KEYWORD +*CONTROL_FORMING_BESTFIT +$ IFIT NSKIP GAPONLY IFAST IFSET + 1 -5 0 1 0 +scan.k +*INCLUDE +spbk_NoSS.k +*END +Example 2 – fitting with an excluded node set: +From the previous example, the included source file spbk_NoSS.k now consists of node +set 128. The node set, which is defined in the file spbk_NoSS.k, which may feature +geometry that are not a part of the target mesh, is being excluded (IFSET = -128) from +participating in the best fitting. Alternatively, the unwanted nodes can be just deleted +from the source file. +*KEYWORD +*CONTROL_FORMING_BESTFIT +$ IFIT NSKIP GAPONLY IFAST IFSET + 1 -5 0 1 -128 +scan.k +*INCLUDE +spbk_NoSS.k +*END +Example 3 – fitting with NSETS and NSETT (recommended): +In the following partial keyword example (shown in Figure 12-22) a source mesh +sourcemesh.k is being best fitted to a target mesh targetmesh.k. A node set with ID 1 +on the source mesh is defined consisting of nodes 1001 1002 and 1003 and a +corresponding node set with ID 2 on the target mesh is defined and consists of nodes 1, +2 and 3. +Node ID 1001 and 1 are both located at the center of a dart on the top surface of the hat- +shaped part. Node ID 1002 and 2 are selected at the center of an arc of an cutout hole. +Lastly, node ID 1003 and 3 are at the center of a tangent line of a radius. With the +NSKIP set a “-5”, the search will be done skipping every 5 mm of distance. In this +example, since the source and target meshes are exactly the same, the normal distance, +as displayed by “thickness” is nearly zero everywhere. +*CONTROL_FORMING_BESTFIT +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +$# IFIT NSKIP GAPONLY IFAST IFSET NSETS NSETT + 1 -5 0 1 0 1 2 +$# FILENAME +targetmesh.k +*INCLUDE +sourcemesh.k +*SET_NODE_LIST +1 +1,2,3 +*SET_NODE_LIST +2 +1001,1002,1003 +Revision information: +This feature is available starting from LS-DYNA Revision 96427 double precision SMP. +The variable IFSET is available starting from Revision 96696. The variables NSETS, +NSETT are available starting from Revision 99369. The VECTOR option is available +starting from Revision 112655. +Node 1 +Node 3 +Node 1002 +Node 2 +Node 1001 +Node 1003 +Source mesh +Target mesh +Best fit results of part separation +Contours of shell thickness +min=-9.39123e-06 at elem# 102 +max=8.45032e-06 at elem# 149 +Node 1: geometry feature +such as the center of a dart +is a preferred choice to be +one of the three nodes. +Node 3: the +center node of a +tangent line may +also be used. +Node 2: the +center of an arc +of a hole can +also be used to +select one of the +three nodes. +Part Separation +(mm) +8.450e-06 +6.665e-06 +4.881e-06 +3.097e-06 +1.313e-06 +4.706e-07 +-2.255e-06 +-4.039e-06 +-5.823e-06 +-7.607e-06 +-9.391e-06 +Best fit results - color contour of part separation plotted with +"thickness" from the output file "Bestfit.out" +Figure 12-22. Best fit of two meshes with orientations greater than 30 degrees +from each other. +*CONTROL_FORMING_INITIAL_THICKNESS +Purpose: This keyword is used to specify a varying thickness field in a specific +direction on a sheet blank (shell elements only) as a result of a metal forming process +such as a tailor-rolling, to be used for additional metal forming simulation. Another +related keyword includes *ELEMENT_SHELL_THICKNESS. + Card 1 +1 +2 +Variable +PID +LCID +Type +I +I +3 +X0 +F +4 +Y0 +F +5 +Z0 +F/I +6 +VX +F +7 +VY +F +8 +VZ +F +Default +none +none +none +none +none +none +none +none + VARIABLE +DESCRIPTION +PID +LCID +Part ID of the sheet blank to be defined with varying thickness, as +in *PART. Currently only 1 PID is allowed. +Load curve ID defining thickness (Y-values) vs. distance (X- +values) starting from position coordinates (X0, Y0, Z0) and in the +direction of a vector [VX, VY, VZ], as in *DEFINE_CURVE. +X0, Y0, Z0 +Starting position coordinates. +VX, VY, VZ +Vector components defining the direction of the distance in the +load curve. +Background: +Tailor-rolling is a process used to vary the thickness of the blank. A judiciously +designed and manufactured tailor-rolled blank will reduce the number of parts +(reinforcements) involved in the stamping process, as well as the number tools needed +to make them. By reducing the number of spot welds, tailor-rolled pieces also possess +superior structural integrity. +Remarks: +1. Beyond the last data point LS-DYNA extrapolates the load curve specified in +LCID as being constant. +2. This card overrides thicknesses set with the *SECTION_SHELL keyword. +Application example: +An excerpt from an input deck containing a characteristic example of this card’s +application is given below. In this example the blank is part ID 1. The axis of the load +curve starts at position (−295, −607, −43) and the direction along which the load curve +sets the thickness is given by (524, 607, 0). For each of the load curve’s abscissa values, +𝑡, the corresponding geometrical coordinate is given by: +𝒓 = +−295 +−607 +−43 ⎦ +⎥⎤ + +⎢⎡ +⎣ +524 +607 +0 ⎦ +⎥⎤ 𝑡 +⎢⎡ +⎣ +For negative values along the load curve, 𝑡 < 0, and values of 𝑡 > 101.0, the thickness is +extrapolated as a constant value of 0.8, and 0.9, respectively. +*CONTROL_FORMING_INITIAL_THICKNESS +$ PID LCID X0 Y0 Z0 VX VY VZ + 1 1012 -295.0 -607.0 -43.0 524.0 607.0 0.0 +*DEFINE_CURVE +1012 +0.0, 0.8 +21.0, 0.9 +43.0, 1.0 +65.0, 1.1 +82.0, 1.0 +101.0, 0.9 +In Figure 12-23, a sheet blank is defined with a varying thickness across its surface in a +vector direction pointed from the start to end point. The thickness variation vs. the +distance from starting point in section A-A is shown in Figure 12-24. +Revision information: +This feature is available in LS-DYNA starting in Revision 82990. +Contours of shell thickness +min=0.635661 at elem# 175119 +max=1.29457 at elem# 177147 +Ending point +(distance=802mm) +Starting point +(distance=0) +Thickness (mm) +1.295 +1.229 +1.163 +1.097 +1.031 +0.965 +0.899 +0.833 +0.767 +0.702 +0.636 +Figure 12-23. Define a varying thickness field across the sheet blank. +Input +Response +) +( +1.4 +1.3 +1.2 +1.1 +1.0 +0.9 +0.8 +0.7 +0.6 +0.0 +200.0 +400.0 +600.0 +800.0 +Distance Along Section (mm) +Figure 12-24. Thickness variation across section A-A +*CONTROL_FORMING_MAXID +Purpose: This card sets the node and element ID numbers for an adaptive sheet blank. +The new node and element number of the adaptive mesh will start at the values +specified on this card, typically greater than the last node and element number of all +tools and blanks in the model. This keyword is often used in multi-stage sheet metal +forming simulation. The *INCLUDE_AUTO_OFFSET keyword is related. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID +MAXIDN MAXIDE +Type +I +I +I +Default +none +none +none + VARIABLE +DESCRIPTION +PID +Part ID of the sheet blank, as in *PART. +Node ID number from which adaptive node ID numbers will be +created. +Element ID number from which adaptive element ID numbers +will be created. +MAXIDN +MAXIDE +Remarks: +In a multi-stage automatic line die simulation the adaptivity feature may generate node +and element IDs that collide with those of the tools used in the later stages of the +process. Before the calculation begins, the set of IDs used by the tools is known. By +setting MAXIDN to a value greater than the largest tool node ID and MAXIDE to a +value greater than the largest tool element ID, it is guaranteed that refinement during +the early stages will not lead to conflicts with tool IDs in the later stages. +The following example shows this feature applied in a 2D trimming simulation. Nodes +and elements ID numbers generated from an adaptive trim simulation will be larger +than the specified ID numbers of 5921980 and 8790292, respectively, for a sheet blank +with part ID of 4. +*KEYWORD +*INCLUDE_TRIM +sim_trimming.dynain +⋮ +*CONTROL_ADAPTIVE_CURVE +$ IDSET ITYPE N SMIN + &blksid 2 2 0.6 +*CONTROL_CHECK_SHELL +$ PSID IFAUTO CONVEX ADPT ARATIO ANGLE SMIN + &blksid1 1 1 1 0.250000150.000000 0.000000 +*INCLUDE +EZtrim.k +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*DEFINE_CURVE_TRIM_NEW +$# tcid tctype tflg tdir tctol toln nseed1 nseed2 + 90914 2 0 1 1.250000 1.000000 0 0 +sim_trimming_trimline_01.igs +*DEFINE_VECTOR +$# vid xt yt zt xh yh zh cid + 1 0.000 0.000 0.000 0.000 0.000 1.000000 0 +*CONTROL_FORMING_MAXID +$ pid maxidn maxide + 4 5921980 8790292 +*END +Revision Information: +This feature is available starting in LS-DYNA Revision 84159. +*CONTROL_FORMING_ONESTEP_{OPTION} +Purpose: This keyword activates a one-step solution using the total strain theory +approximation to plasticity (also known as deformation theory) to implement an +inverse method. Given the final geometry, the one-step method uses LS-DYNA’s +implicit statics solver to compute an approximate solution for (1) the stresses and +strains in the formed part, (2) the thickness of the formed part, and (3) the size of the +initial blank (unfolded flat blank). This method is useful for estimating the initial blank +size with attendant material costs, and for augmenting crashworthiness models to +account for metal forming effects, such as plastic strains and blank thickness in crash +simulation. +NOTE: The input must contain only one “part”, consisting +entirely of shells, which is taken to be the final geometry. +1. This “part” may involve more than one PID to accommo- +date welded blanks, +2. +3. +it must be composed entirely of shells, and, +its external boundary must consist of a single closed loop. +Keywords associated with *CONTROL_FORMING_ONESTEP are: +*CONTROL_FORMING_UNFLANGING +*INTERFACE_BLANKSIZE_DEVELOPMENT. +Available options include: + +AUTO_CONSTRAINT +DRAWBEAD +FRICTION +TRIA +QUAD +QUAD2 (default) +Summary of keyword options: +1. The AUTO_CONSTRAINT option excludes rigid body motion from the implicit +solution by automatically adding nodal constraints. A deck with a *CON- +TROL_FORMING_ONESTEP card should contain at most one *CONTROL_- +FORMING_ONESTEP_AUTO_CONSTRIANT card. In addition, starting from +Revision 91229, three nodes can be specified on the final part to position the +unfolded blank for easier blank nesting, and for blank alignment in forming +simulation. +2. The DRAWBEAD option is used to apply draw bead forces in addition to those +provided by AUTOBD field in Card 1. A deck containing a *CONTROL_- +FORMING_ONESTEP card may contain as many *CONTROL_FORMING_ON- +ESTEP_DRAWBEAD cards as there are draw beads to be defined. +3. The FRICTION option applies friction along the edge of the part based on the +binder tonnage input by the user in the DBTON field of card 1. A deck contain- +ing a *CONTROL_FORMING_ONESTEP card may contain as many *CON- +TROL_FORMING_ONESTEP_FRICTION cards as there are friction node sets to +be defined. +4. Originally all quadrilateral elements in the model were split into two triangular +elements internally for calculation. This original formulation is set as option +TRIA as of Revision 112682. The option QUAD supports quadrilateral elements +and implements some improved algorithm, which result in better results. In +addition, this option greatly improves calculation speed under multiple CPUs +in SMP mode, and is available starting in Revision 112071. The option QUAD2 +is yet another improvement over the option QUAD with enhanced element +formulation, which further improves results in terms of thinning and plastic +strain with slightly longer CPU times. Calculation speed comparisons among +the three options can be found in Performance among options TRIA, QUAD. +The option QUAD2 is set as a default as of Revision 112682 and is the recom- +mended option. +Card 1 for no option, . + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +OPTION TSCLMAX AUTOBD TSCLMIN EPSMAX +LCSDG +DMGEXP +Type +Default +I +6 +F +F +F +F +I +F +1.0 +0.0 +1.0 +1.0 +none +none +Card 1 for option AUTO_CONSTRAINT. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ICON +NODE1 +NODE2 +NODE3 +Type +I +I +I +I +Default +none +none +none +none +Card 1 for option DRAWBEAD. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NDSET +LCID +TH +PERCNT +Type +I +I +F +F +Default +none +none +0.0 +0.0 +Card 1 for option FRICTION. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NDSET +BDTON +FRICT +Type +I +F +F +Default +none +0.0 +0.12 +Card 2 for no option . + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +Default + VARIABLE +OPTION +TSCLMAX +FLATNAME +A +none +DESCRIPTION +Options to invoke the one-step solution methods which account +for undercut conditions in the formed part: +EQ.6: One-step solution with unfolded blank (flat) provided by +LS-PrePost . Card #2 is required. +EQ.7: One-step solution with blank automatically unfolded in +LS-DYNA. Card #2 is a blank line. This option is rec- +ommended. +L.T.0: If a negative sign precedes any of the above OPTIONs, +the stress and strain output in the file onestepresult will +be in a large format (E20.0), which leads to more accurate +stress results. +If not zero, it defines a thickness scale factor limiting the +maximum thickness in the part. +For example, if the maximum thickness allowed is 0.8mm for a +blank with initial thickness of 0.75mm TSCLMAX can be set to +1.0667. All thicknesses that are computed as more than 0.8mm in +the sheet blank will be reset to 0.8mm. The scale factor is useful +in advance feasibility analysis where part design and stamping +process have not been finalized and could potentially cause large +splits or severe wrinkles during unfolding, rendering the forming +results unusable for crash/safety simulation. +AUTOBD +TSCLMIN +EPSMAX +LCSDG +DMGEXP +*CONTROL_FORMING_ONESTEP +DESCRIPTION +Apply a fraction of a fully locked bead force along the entire +periphery of the blank. + The fully locked bead force is +automatically calculated based on a material hardening curve +input. AUTOBD can be increased to easily introduce more +thinning and effective plastic strain in the part. +LT.0.0: Turns off the “auto-bead” feature. +EQ.0.0: Automatically applies 30% of fully locked force. +GT.0.0: Fraction input will be used to scale the fully locked +force. +If not zero, it defines a thickness scale factor limiting the +maximum thickness reduction. +For example, if the minimum thickness allowed is 0.6mm for a +blank with initial thickness of 0.75mm TSCLMIN can be set to 0.8. +All thicknesses that are computed as less than 0.6mm in the sheet +blank will be reset to 0.6mm. The scale factor is useful in advance +feasibility analysis where part design and stamping process have +not been finalized and could potentially cause large splits or +severe wrinkles during unfolding, rendering the forming results +unusable for crash/safety simulation. +If not zero, it defines the maximum effective plastic strain +allowed. All computed effective plastic strains that are greater +than this value in the blank will be set to this value. +Load curve ID defining equivalent plastic strain to failure vs. +stress triaxiality, see *MAT_ADD_EROSION. +for +see +Exponent +*MAT_ADD_EROSION. Damage accumulation is written as +history variable #6 in the file onestepresult. +accumulation, +nonlinear +damage +ICON +Automatic nodal constraining option to eliminate the rigid body +motion: +EQ.1: Apply. +VARIABLE +NODE[1,2,3] +NDSET +LCID +TH +DESCRIPTION +Node IDs for which the position is fixed during the unfolding. +The position of these nodes in the calculated unfolded piece will +coincide with the corresponding nodes in the input. The +transformed and unfolded blank will be written in a keyword file +“repositioned.k”. When these fields are undefined the orientation of +the unfolded blank is arbitrary. +Node set ID along the periphery of the part, as defined by +keyword *SET_NODE_LIST. +Load curve ID that defines the material hardening curve. +Thickness of the unformed sheet blank. +PERCNT +Draw bead lock force fraction of the fully locked bead force. +BDTON +Binder tonnage used to calculate friction force. +FRICT +Coefficient of friction. +FLATNAME +File name of the initial unfolded blank by LS-PrePost . This is needed only for the OPTION = 6. Leave a blank +line for OPTION = 7. +About One-Step forming solution: +One-step solution employs the total strain (or deformation) theory of plasticity in place +of the more realistic incremental strain (or flow) theory. The total deformation theory +expresses stress as a function of total strain; whereas the incremental strain theory requires +that LS-DYNA compute a stress update at each time step (strain increment) from the +deformation that occurred during that time step. In deformation theory, the results, +therefore, do not depend on strain path, forming history, or the details of the stamping +process. +When this card is included, the input must contain the final geometry from which LS- +DYNA calculates the initial flat state using the inverse method. The one-step solution +results can get close to the incremental results only when the forming process involves a +linear strain path for which the deformation is either monotonically increasing or +decreasing. In most cases total strain theory does not match incremental forming. +Path independence leads to several key simplifications: +1. Binder and addendum geometry are not required. There is no need to measure +or model these geometries. +2. The solution is independent of stamping die processes (including part tipping). +3. There is no need for contact treatment since there are no tools and dies +involved. +The one-step solution is mostly used for advance formability studies in which the user +needs to quickly compare a wide range of different design alternatives. With this +method the user can evaluate blank size, estimate material cost, and generate a first +guess for blank size development . This method is also widely used to +initialize forming stresses and strains in crash and occupant safety analysis. +Input details: +1. Mesh. In addition to the usual material and physical property definitions, this +method requires that the final part be fully meshed using shell elements. This +mesh must satisfy a different set of requirements than the tooling mesh. In +particular, along the part bend radius, there is no need to build six elements +along the arc length as one would do for the punch/die radius; two elements +may be enough. A mesh consisting of uniformly distributed quadrilateral shell +elements is ideal. All elements in the mesh must also have normal consistency. +With LS-PrePost 4.0, this kind of mesh can be generated using Mesh → AutoM → +Size. Since this method uses an implicit static solution scheme, the computa- +tional cost is controlled by the number of elements; element size has no effect. +Furthermore, it is important to note that if one wants to obtain forming results +that are closer to the incremental forming results, the part in the one-step input +should be similar in size to the final formed blank shape in the incremental +forming (before trimming). +2. Holes. Any trimmed-out holes can be filled (but not necessary). The filling can +be done semi-automatically using LS-PrePost 4.0 by selecting Mesh → EleGen → +Shell → Shell by Fill_Holes → Auto Fill. The filled area of the part can be saved in +a different part, as multiple parts (PID) are allowed. The forming results may +depend on whether or not the holes are filled. +3. Unfolding. For OPTION = 6, the unfolded blank can be obtained from LS- +PrePost via EleTol → Morph → Type = Mesh_Unfolding → Unfold. The unfolded +mesh can be saved as a keyword file and used as input . With OPTION = 7, LS-DYNA unfolds the mesh itself. +4. Element Formulation. Shell element of type 2 and 16 are supported. Since this +feature uses the implicit method, type 16 is more convergent, computationally +efficient, and, therefore, strongly recommended. Results are output on all inte- +gration points, as seen in the ELFORM and NIP variables in *SECTION_SHELL. +5. Supported Materials. Currently, *MAT_024, and *MAT_037 are supported. +The user must provide a material hardening curve either in the LCSS field of +*MAT_024 or in the HLCID field of *MAT_037. For *MAT_024 tables are sup- +ported. Future releases will add support for bilinear hardening with the ETAN +feature. Additionally, in *MAT_024, strain rate is ignored, even when the vari- +ables C, and P are set. +6. Boundary Conditions. The primary “boundary/loading condition” for the +one-step solution is the draw bead forces, which are set with the AUTOBD field +or with the DRAWBEAD keyword option. +a) With the DRAWBEAD option, draw bead forces are applied on a user de- +fined node set . A fraction of the full lock force, determined +by the tensile strength and sheet thickness, can be specified. The larger +the fraction, the less the metal will flow into the die resulting in more +stretching and thinning. +b) Boundary conditions may also be set using the “Auto Beads” feature with which draw bead forces are automatically ap- +plied to all nodes along the part boundary. The users must specify the +fraction of the fully locked bead force to be applied. The default value of +30% is sufficient for crash/occupant safety applications. +The last important, but often overlooked, “boundary condition” is the part’s +shape. For example, an oil pan with a larger flange area will experience greater +thinning in the part wall, whereas having a smaller flange area will have the +reverse effect. To obtain results that are closer to the incremental strain theory, +additional materials may need to be added to the final part geometry in cases +where the sheet blank is not “fully developed,” meaning no trimming is re- +quired to finish the part. +7. Friction. Friction effects can be included with the FRICTION option. The +frictional force is based on an expected binder tonnage, and is a percentage of +the input force. Note that the binder tonnage value is used exclu- +sively in calculating friction forces. The binder tonnage is not actually applied +on the binder as a boundary condition. +8. Rigid Body Motion. LS-DYNA will automatically add nodal constraints to +prevent rigid body motion when the AUTO_CONSTRAINT option is used and +ICON is set to 1. +9. +Implicit Solver Options. All other implicit cards, such as *CONTROL_IM- +*CONTROL_IM- +PLICIT_GENERAL, +PLICIT_SOLVER, +*CONTROL_IMPLICIT_- +TERMINATION, etc., are used to set the convergence tolerance, termination +criterion, etc. The two most important variables controlling the solution con- +*CONTROL_IMPLICIT_SOLUTION, +*CONTROL_IMPLICIT_AUTO, +vergence are DELTAU from *CONTROL_IMPLICIT_TERMINATION, and +DCTOL from *CONTROL_IMPLICIT_SOULTION. Experience has shown that +they should be set to 0.001 and 0.01, respectively, to obtain the most efficient +solution with the best results. Typically, four implicit steps are sufficient, and +DT0 in *CONTROL_IMPLICIT_GENERAL and ENDTIM in *CONTROL_TER- +MINATION should be set accordingly. For difficult parts, more steps maybe +needed. For some parts, ILIMIT in *CONTROL_IMPLICIT_SOLUTION may +need to be set to “1” for the full Newton iteration. +10. Blank Card. Card #2 for no option is a blank card, but it must be +present. +Output: +Results are stored in an ASCII file named “onestepresult” using the dynain format. +This file contains the forming thickness, the stress and the strain fields on the final part. +It can be plotted with LS-PrePost. One quick and useful LS-PrePost plotting feature is +the “formability contour map”, which colors the model to highlight various forming +characteristics including cracks, severe thinning, wrinkles, and good surfaces. The +formability map feature is located in Post → FLD → Formability. +Additionally, the final estimated blank size in its initial, flat state is stored in the d3plot +files. The d3plot files also contain intermediate shapes from each implicit step. The +final blank mesh in its flat state can be written to a keyword file using LS-PrePost by the +following steps: +1. Go to Post → Output → Keyword, +2. +check the box to include Element and Nodal Coordinates +3. move the animation bar to the last state, and, +4. +click on Curr and Write. +In addition, blank outlines can be created by: +1. menu option Curve → Spline → From Mesh (Method), +2. +3. +4. +5. +checking Piecewise → byPart, +select the blank, +click on Apply, and, +finally, save the curves in IGES format using the File menu at the upper left +corner. +Effect of TSCLMAX, TSCLMIN and EPSMAX: +During the early stage of product design, the initial product specifications may lead to +large strains and excessive thinning on the formed panel. The ensuing one-step results +would not be suitable to be used in a crashworthiness simulation. However, these +kinds of forming issues are certain to be fixed as a natural part of the design and +stamping engineering process. The variables TSCLMAX, TSCLMIN and EPSMAX are +thus created to impose artificial limits on the thinning and plastic strains. The variables +provide convenient way to run a crash simulation with approximate and reasonable +forming effects before the design is finalized. In the keyword below (which is a part of +the firewall model with original thickness of 0.75mm), TSCLMIN and EPSMAX are set +to 0.8 and 0.3, respectively. +*CONTROL_FORMING_ONESTEP +$ OPTION TSCLMAX AUTODB TSCLMIN EPSMAX + 7 0.5 0.8 0.3 +The thickness and effective plastic strain plots for the firewall model are shown in +Figures 12-29 and 12-30, respectively. The minimum value in the thickness contour plot +and maximum value in the plastic strain contour plot as shown in the upper left corner +correspond to the values specified in TSCLMIN and EPSMAX, respectively. +Similarly, TSCLMAX can be set to 1.0667 to limit the max thickening in the part to +0.8mm: +*CONTROL_FORMING_ONESTEP +$ OPTION TSCLMAX AUTODB TSCLMIN EPSMAX + 7 1.0667 0.5 0.8 0.3 +Reposition of unfolded flat blank: +Often times the input to one-step simulation is the final product part in the car axis +system. However, after the simulation, the unfolded flat blank will be in a different +orientation and position, requiring users to manually reposition the blank to its desired +orientation and position. The variables NODE1, NODE2, NODE3 allow users to specify +three nodes so that the blank is transformed onto the final part (the input), +superimposing the exact same three nodes in both parts. In an example shown in +Figure 12-32, the three nodes (Nodes 197, 210 and 171) are defined near the edges of two +holes. The transformed and unfolded flat blank (written in a keyword file “reposi- +tioned.k”) is seen superimposed onto the final part according to the three nodes +specified (Figure 12-32 bottom). If these nodes are not defined, the simulation will +result in the unfolded flat blank in a state shown in Figure 12-32 (top), undesirable to +most users. +Damage accumulation D +*MAT_ADD_EROSION): +*CONTROL_FORMING_ONESTEP +is calculated based on +(refer +to manual section +DMGEXP +𝐷 = ( +𝜀𝑝 +𝜀𝑓 +) +In the example below, load curve #500 provides plastic failure strain vs. stress +triaxiality and DMGEXP is assumed to be 1.254. Since the damage accumulation is +written into the file onestepresult as history variable #6, the variable NEIP in +*DATABASE_EXTENT_BINARY should be set to at least ‘6”. +*CONTROL_FORMING_ONESTEP +$ OPTION AUTODB TSCLMIN EPSMAX LCSDG DMGEXP + 7 0.8 0.3 500 1.254 +*DEFINE_CURVE +500 +-0.3,0.6 +-0.2,0.3 +0.0,0.2 +0.2,0.25 +0.4,0.46 +0.65,0.28 +0.9,0.18 +*DATABASE_EXTENT_BINARY +$ NEIPH NEIPS MAXINT STRFLG SIGFLG EPSFLG RLTFLG ENGFLG + 6 7 1 +$ CMPFLG IEVERP BEAMIP DCOMP SHGE STSSZ + 1 2 +The damage accumulation contour map from the file onestepresult can be plotted in LS- +PrePost. +Effect of hole-cut on the forming results: +In Figure 12-31, a thickness contour plot of a one-step calculation on the NCAC Taurus +firewall model with its holes unfilled is shown. The unfilled case will undergo slightly +less thinning, since the holes will expand as material flows outward away from the hole. +However, the thicknesses with holes filled are likely closer to reality, since the holes are +mostly filled during forming on the draw panel and then trimmed off afterwards in a +trim process. On the other hand, it is important to realize that not all the holes are filled +in a draw panel. Some holes are cut inside the part in the scrap area (but not all the way +to the trim line) during draw process to allow material to flow into areas that are +difficult to form, so as to avoid splitting. +Application example: +The following example provides a partial input file with typical control cards. It will +iterate for four steps, with auto beads of 0% lock force applied around the part +boundary, and with automatic nodal constraints. +*CONTROL_TERMINATION +$ ENDTIM + 1.0 +*CONTROL_IMPLICIT_GENERAL +$ IMFLAG DT0 + 1 0.25 +*CONTROL_FORMING_ONESTEP +$ OPTION AUTODB + 7 +*CONTROL_FORMING_ONESTEP_AUTO_CONSTRAINT +$ ICON + 1 +*CONTROL_IMPLICIT_TERMINATION +$ DELTAU + 0.001 +*CONTROL_IMPLICIT_SOLUTION +$ NSLOLVR ILIMIT MAXREF DCTOL ECTOL + 2 11 1200 0.01 1.00 +*CONTROL_IMPLICIT_SOLVER +$ LSOLVR + 5 +*CONTROL_IMPLICIT_AUTO +$ IAUTO ITEOPT ITEWIN DTMIN DTMAX + 0 0 0 0.0 0.0 +Additional cards below specify extra bead forces of 45% and 30% applied to node sets +22 and 23 along the part periphery, respectively. Also, the resulting friction forces with +friction coefficient of 0.1 and binder tonnage of 10000.0 N used for friction force are +applied on the same node sets. +*CONTROL_FORMING_ONESTEP_DRAWBEAD +$ NDSET LCID TH PERCNT + 22 200 1.6 0.45 +*CONTROL_FORMING_ONESTEP_DRAWBEAD + 23 200 1.6 0.30 +*CONTROL_FORMING_ONESTEP_FRICTION +$ NDSET BDTON FRICT + 22 10000.0 0.1 +*CONTROL_FORMING_ONESTEP_FRICTION +$ NDSET BDTON FRICT + 23 10000.0 0.1 +The one-step forming results for the NCAC Taurus model’s firewall are shown in +Figure 12-25. The average element size across the blank is 8mm, and the trimmed part +(with holes filled) consists of 15490 elements. *MAT_24 was used with BH210 material +properties. On a 1 CPU Xeon E5520 Linux machine, it took 4 minutes to complete the +run with a total of four steps. The thickness, the plastic strain, and the blank size +prediction were reasonable, as shown in Figures 12-26, 12-27 and 12-28. +Performance among options TRIA, QUAD and QUAD2: +The following partial keyword input is an example of using the option QUAD. Note +the draw bead force parameter AUTOBD is set at 0.5. Calculation speed comparison +among options QUAD, QUAD2 and TRIA can be found in Table 12-1. +*KEYWORD +*include +model.k +*CONTROL_TERMINATION +1.0 +*CONTROL_FORMING_ONESTEP_QUAD +$# option maxthick autobd thinmin epsmax + 7 0.5 +*CONTROL_FORMING_ONESTEP_AUTO_CONSTRAINT + 1 +*CONTROL_IMPLICIT_GENERAL +$# imflag dt0 imform nsbs igs cnstn form zero_v + 1 0.2500 2 1 0 0 0 0 +*CONTROL_IMPLICIT_TERMINATION +$# deltau delta1 ketol ietol tetol nstep + 0.001000 0.000 0.000 0.000 0.000 0 +*CONTROL_IMPLICIT_NONLINEAR +$# nsolvr ilimit maxref dctol ectol not used lstol rssf + 12 11 200 0.010000 0.100000 0.000 0.000 0.000 +$# dnorm diverg istif nlprint + 0 0 0 2 +$# arcctl arcdir arclen arcmth arcdmp + 0 0 0.000 1 2 +*CONTROL_IMPLICIT_SOLVER +5 +*PART + 5000000 5000000 5000000 +*SECTION_SHELL + 5000000 16 1. 5. 1. + 0.72 0.72 0.72 0.72 +... +Table 12-1 Calculation speed improvement with and without option _QUAD. +Number +of +elements +Calculation speed (D.P. SMP Rev.112720, 8 CPUs) +Option TRIA +Option QUAD +Option QUAD2 +A hat shape part +71000 +21.0 min +14.1 min +16.6 min +A upper dash +panel +61700 +24.5 min +11.5 min +17.2 min +Revision information: +This feature is available starting in Revision 67778 SMP and double precision only. +Over time, improvements are made to improve accuracy and speed up the calculation +time; revision 110117 or later is recommended. Historic revisions are listed as follows: +1)Revision 73442: output of stress tensors +2)Revision 75156: output of strain tensors. +3)Revision 75854: variables THINPCT and EPXMAX are available. +4)Revision 76709: holes are allowed. +5)Revision 91229: variables NODE1, NODE2, NODE3 are available. +6)Revision 108229: variables LCSDG and DMGEXP are available. +7)Revision 111311: variable TSCLMAX is available. +8)Revision 112071: option QUAD is available. +9)Revision 112682: original formulation is designated as option TRIA. A new option +QUAD2 is activated. +10)Revision 109680: negative value of OPTION for a large format stress and strain +output. +Figure 12-25. A trimmed dash panel (firewall) with holes auto-filled using +LS-PrePost 4.0 (original model courtesy of NCAC Taurus crash model). +Contours of shell thickness +min=0.478084, at elem# 3210698 +max=1.10908, at elem# 3211511 +Thickness (mm) +0.750 +0.725 +0.700 +0.675 +0.650 +0.625 +0.600 +0.575 +0.550 +0.525 +0.500 +Figure 12-26. Shell thickness prediction (t0 = 0.75mm). +Contours of plastic strain +max ipt. value +min=0, at elem# 3008783 +max=0.46, at elem# 3210698 +Plastic strain +0.460 +0.414 +0.368 +0.322 +0.276 +0.230 +0.184 +0.138 +0.092 +0.046 +0.000 +Figure 12-27. Effective plastic strain Prediction. +Figure 12-28. Initial blank size prediction (flat, not to scale). +Contours of shell thickness +min=0.6, at elem# 3206053 +max=0.923214, at elem# 3211511 +Thickness (mm) +0.750 +0.725 +0.700 +0.675 +0.650 +0.625 +0.600 +0.575 +0.550 +0.525 +0.500 +Figure 12-29. Blank thickness prediction with TSCLMIN = 0.8. +Contours of plastic strain +max ipt. value +min=0, at elem# 3008801 +max=0.3, at elem# 3204379 +Plastic strain +0.300 +0.270 +0.240 +0.210 +0.180 +0.150 +0.120 +0.090 +0.060 +0.030 +0.000 +Figure 12-30. Effective plastic strain with EPSMAX = 0.3. +Contours of shell thickness +min=0.538193, at elem# 3209452 +max=0.974493, at elem# 3211511 +Thickness (mm) +0.750 +0.725 +0.700 +0.675 +0.650 +0.625 +0.600 +0.575 +0.550 +0.525 +0.500 +Figure 12-31. Blank thickness with trimmed holes (t0 = 0.75mm). +Unfolded flat blank +Final part +Final part +Unfolded flat blank +N197 +Figure 12-32. An example of the results when using the NODE1, NODE2, and +NODE3 feature (bottom) and without using the feature (top), courtesy of +Kaizenet Technologies Pvt Ltd, India. +N210 +N171 +*CONTROL_FORMING_OUTPUT_{OPTION} +Available options include: + +INTFOR +Purpose: This card defines the times at which states are written to the d3plot and intfor +files based on the tooling’s distances from the home (final) position. When the INTFOR +option is set this keyword card controls when states are written to the intfor file, +otherwise it controls the d3plot file. This feature may be combined with parameterized +input and/or automatic positioning of the stamping tools using the *CONTROL_- +FORMING_AUTOPOSITION_PARAMETER card. +NOTE: When this card is present no states are written except +for those specified on this card. This card supersedes +the *DATABASE_BINARY_D3PLOT card. +Forming Output Cards. Repeat as many times as needed to define additional outputs +in separate tooling kinematics curves. The next keyword (“*”) card terminates the +input. + Card 1 +1 +2 +3 +4 +5 +6 +Variable +CID +NOUT +TBEG +TEND +Y1/LCID +Y2/CIDT +7 +Y3 +F +8 +Y4 +F +Type +I +Default +none +I +0 +F +F +F/I +F/I +0.0 +none +none +none +none +none + VARIABLE +CID +DESCRIPTION +ID of a tooling kinematics curve. This curve is integrated so that +the specified output distances can be mapped to times. +For correct distance-to-time mapping CID must be applied to the +tool of interest using a *BOUNDARY_PRESCRIBED_MOTION_- +RIGID card. The ordinate scale factor SFO in the *DEFINE_- +CURVE is supported in this keyword starting from Revision +82755. +) +( +- +0.0 +-10 +-20 +-30 +-40 +-50 +Y1 Y2 Y3 +Y4 +NOUT +&clstime +Punch displacement +NOUT +Y1 +Y2 +Y3 +Y4 +&endtime +0.0 +0.002 +0.004 +0.006 +0.008 +0.01 +0.012 +Explicit time (sec.) +Figure 12-33. An output example for closing and drawing. See the example +provided at the end of this section. + VARIABLE +NOUT +TBEG +TEND +DESCRIPTION +Total number states written to the d3plot or intfor databases for +the tooling kinematics curve, CID, excluding the beginning and +final states. If NOUT is larger than the number of states specified +by either LCID or Yi fields (5 through 8), the remaining states are +evenly distributed between TBEG and the time corresponding to +the biggest Yi from the home position, as shown in Figure 12-33. +If NOUT is left as blank or as “0”, the total number of output +states will be determined by either LCID or Yi’s. +Start time of the curve. This time should be consistent with the +BIRTH in *BOUNDARY_PRESCRIBED_MOTION_RIGID. +End time of the curve. This time should be consistent with the +DEATH in *BOUNDARY_PRESCRIBED_MOTION_RIGID. This +time is automatically reset backward removing any idling time if +the tool finishes traveling early, so output distances can start from +the reset time. A state is written at TEND. +Y1/LCID, +Y2, Y3, Y4 +Y2/CIDT +*CONTROL_FORMING_OUTPUT +DESCRIPTION +Y1/LCID.GT.0: All four variables (Y1, Y2, Y3, Y4) are taken to +be the distances from the punch home, where +d3plot files will be output. +Y1/LCID.LT.0: The absolute value of Y1/LCID (must be an +integer) is taken as a load curve ID . Only the abscissas in the load +curve, which are the distances to punch home, +are used. These distances specify the states that +are written to the d3plot files. Ordinates of the +curve are ignored. This case accommodates +more states than is possible with the four varia- + Furthermore, when +bles Y1, Y2, Y3, Y4. +Y1/LCID < 0, Y2, Y3, and Y4 are ignored. +Available starting from Revision 112604, the +output will be skipped for any negative abscissa +in the load curve. Note all abscissas being nega- +tive are not allowed. +Y2/CIDT.GT.0: The input is taken as the distance from the +punch home, where a d3plot file will be output. +Y2/CIDT.LT.0: The absolute value of Y2/CIDT (must be an +integer) is taken as a load curve ID . Only the abscissas in the load +curve, which are the simulation times, are used. +These times specify the states that are written to +the d3plot files. Ordinates of the curve are ig- +nored. Note this time-dependent load curve +will output additional d3plot files on top of the +d3plot files already written in case Y1/LCID < 0 +(if specified). Furthermore, when Y2/CIDT < 0, +Y3 and Y4 are ignored. See an example for us- +age. +Motivation: +In stamping simulations not all time steps are of equal interest to the analyst. This +feature allows the user to save special states, usually those for which wrinkling and +thinning conditions arise as the punch approaches its home position. +This feature is available in Application eZ-Setup in LS-PrePost4.0 (http://ftp.lstc.com/- +anonymous/outgoing/lsprepost/4.0/metalforming/). +Remarks: +1. Keywords *DATABASE_BINARY_D3PLOT and *DATABASE_BINARY_INT- +FOR are not required (ignored if present) to output D3PLOT and INTFOR files +when this keyword is present; +2. +3. +*CONTROL_FORMING_OUTPUT and *CONTROL_FORMING_OUTPUT_- +INTFOR can share the same CIDs; +If columns 5 through 8 are left blank, output (NOUT) will be evenly distributed +through the travel; +4. The variable NOUT has priority over the number of points on the LCID; +5. Distances input (in LCID) that are greater than the actual tool travel will be +ignored; +6. Distance input (in LCID) does not necessarily have to be in a descending or +ascending order. +Applicability: +This keyword is applicable to the parameter VAD of “0” (velocity) in *BOUNDARY_- +PRESCRIBED_MOTION_RIGID, and for explicit dynamics only. Tooling kinematics +profiles of various trapezoids (including right trapezoid) are all supported. Local +coordinate systems are supported. +Y1 Y2 Y3 Y4 +&vcls +0.0 +&tramp +&clstime +Explicit time +Figure 12-34. Specifying d3plot/intfor output at specific distances to punch +home. +Application example for an air draw: +In a keyword example below (air draw, referring to Figures 12-33 and 12-35), a total of +five states will be output during a binder closing. The kinematics are specified by the +curve of ID 1113, which defines tooling kinematics starting time 0.0 and ending at time +&clstime. +Curve 1113 is used to associate the specified distances to the appropriate time step. In +this example NOUT is set to 5. Of these five outputs states the last four will be output +at upper die distance to closing of 3.0, 2.0, 1.0, and 0.5 mm according to the values +specified in the Y1, Y2, Y3, and Y4 fields. +Similarly, a total of eight states will be written to the d3plot file made during draw +forming according curve ID 1115, which defines tooling kinematics starting at time +&clstime, and ending at time &endtime. Of the eight states the last four will be output at +punch distance to draw home of 6.0, 4.0, 3.0, and 1.0 mm; the remaining four outputs will +be evenly distributed between starting punch distance to home and punch distance of 6.0mm to +home. +Likewise, for intfor, 15 states will be written before closing and 18 states after the +closing. The d3plot and intfor files will always be output for the first and last states as a +default; and at where the two curves meet at &clstime, only one d3plot and intfor will be +output. +To output intfor, “S=filename” needs to be specified on the command line, and SPR and +MPR need to be set to “1” on the *CONTACT_… cards. +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*CONTROL_FORMING_OUTPUT +$ CID NOUT TBEG TEND y1 y2 y3 y4 +1113 5 &clstime 3.0 2.0 1.0 0.5 + 1115 8 &clstime &endtime 6.0 4.0 3.0 1.0 +*CONTROL_FORMING_OUTPUT_INTFOR +$ CID NOUT TBEG TEND y1 y2 y3 y4 + 1113 15 &clstime 3.5 2.1 1.3 0.7 + 1115 18 &clstime &endtime 16.0 4.4 2.1 1.3 +*BOUNDARY_PRESCRIBED_MOTION_RIGID +$ typeID DOF VAD LCID SF VID DEATH BIRTH +&udiepid 3 0 1113 -1.0 0 &clstime 0.0 +&bindpid 3 0 1114 1.0 0 &clstime 0.0 +&udiepid 3 0 1115 -1.0 0 &endtime &clstime +&bindpid 3 0 1115 -1.0 0 &endtime &clstime +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*DEFINE_CURVE +1113 +0.0,0.0 +&clsramp,&vcls +&clstime,0.0 +*DEFINE_CURVE +1114 +0.0,0.0 +10.0,0.0 +*DEFINE_CURVE +1115 +0.0,0.0 +&drwramp,&vdraw +&drwtime,&vdraw +The keyword example below illustrates the use of load curves 3213 and 3124 to specify +the states written to the d3plot and intfor files respectively. In addition to the eight +states specified by curve 3213, five additional outputs will be generated. Similarly, in +addition to the 10 intfor states defined by curve 3214, eight additional states will be +output. +*CONTROL_FORMING_OUTPUT +$ CID NOUT TBEG TEND y1 y2 y3 y4 + 1113 13 &clstime -3213 +*CONTROL_FORMING_OUTPUT_INTFOR +$ CID NOUT TBEG TEND y1 y2 y3 y4 + 1113 18 &clstime -3214 +*DEFINE_CURVE +3213 +88.0 +63.0 +42.0 +21.5 +9.8 +5.2 +3.1 +1.0 +*DEFINE_CURVE +3214 +74.0 +68.0 +53.0 +32.0 +25.5 +7.8 +4.2 +2.1 +1.4 +0.7 +Application example for a multiple flanging process: +Referring to Figure 12-36 and a partial keyword example listed below, flanging steels #1 +through #4 are defined as parameters &flg1pid through &flg4pid, respectively, which are +moving in their own local coordinate systems. The termination time &endtime is +defined as pad closing time &clstime plus the maximum travel time of all four flanging +steels. A total of ten d3plot states and ten intfor states are defined for each flanging steel +using curve IDs 980 and 981, respectively. Curve values outside of the last 10 states +(distances) are ignored; and reversed points are automatically adjusted. +In Figure 12-37, locations of d3plot states are indicated by “x” markers for each flanging +steel move. Note that for flanging steels with longer travel distances, there may be +additional d3plot states between the defined points, controlled by distance output +defined for other flanging steels with shorter travels. The total number of d3plot (and +intfor) states is the sum of all nout defined for each flanging steel so care should be +taken to limit the total d3plot (and intfor) states, especially if large number of flanging +steels are present. +*KEYWORD +$ -------------------------closing +*BOUNDARY_PRESCRIBED_MOTION_RIGID +$ typeID DOF VAD LCID SF VID DEATH BIRTH + &upid1 3 0 1113 &padvdir 0 &clstime +*BOUNDARY_PRESCRIBED_MOTION_RIGID_local + &flg1pid 3 0 1114 1.0 0 &clstime + &flg2pid 3 0 1114 1.0 0 &clstime + &flg3pid 3 0 1114 1.0 0 &clstime + &flg4pid 3 0 1114 1.0 0 &clstime +$ -------------------------flanging +*BOUNDARY_PRESCRIBED_MOTION_RIGID +$ typeID DOF VAD LCID SF VID DEATH BIRTH + &upid1 3 0 1115 &padvdir 0 &clstime +*BOUNDARY_PRESCRIBED_MOTION_RIGID_local + &flg1pid 3 0 1116 1.0 0 &clstime + &flg2pid 3 0 1117 1.0 0 &clstime + &flg3pid 3 0 1118 1.0 0 &clstime + &flg4pid 3 0 1119 1.0 0 &clstime +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*DEFINE_CURVE + 1116 + 0.0 0.0 + &tdrwup &vdrw + &tdown1 &vdrw + &drw1tim 0.0 + 1.0E+20 0.0 +*DEFINE_CURVE + 1117 + 0.0 0.0 + &tdrwup &vdrw + &tdown2 &vdrw + &drw2tim 0.0 + 1.0E+20 0.0 +*DEFINE_CURVE + 1118 + 0.0 0.0 + &tdrwup &vdrw + &tdown3 &vdrw + &drw3tim 0.0 +1.0E+20 0.0 +*DEFINE_CURVE + 1119 + 0.0 0.0 + &tdrwup &vdrw + &tdown4 &vdrw + &drw4tim 0.0 + 1.0E+20 0.0 +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*DEFINE_CURVE +980 +60.0 +55.0 +42.0 +40.0 +38.0 +31.0 +23.0 +19.0 +15.0 +13.0 +13.5 +5.0 +3.0 +2.0 +2.5 +1.0 +*DEFINE_CURVE +981 +23.0 +19.0 +15.0 +13.0 +13.5 + ⋮ +*CONTROL_FORMING_OUTPUT +$ -------1---------2---------3---------4---------5---------6---------7---------8 +$ CID NOUT TBEG TEND Y1/LCID + 1116 10 &clstime &endtime -980 + 1117 10 &clstime &endtime -980 + 1118 10 &clstime &endtime -980 + 1119 10 &clstime &endtime -980 +*CONTROL_FORMING_OUTPUT_INTFOR +$ -------1---------2---------3---------4---------5---------6---------7---------8 +$ CID NOUT TBEG TEND Y1/LCID + 1116 10 &clstime &endtime -981 + 1117 10 &clstime &endtime -981 + 1118 10 &clstime &endtime -981 + 1119 10 &clstime &endtime -981 + ⋮ ⋮ ⋮ ⋮ ⋮ +An example of using CIDT: +The example below shows in addition to the 7 states output based on various distances +from punch home, defined by load curve 980, 4 more states are output based on +simulation time, defined by load curve 999. +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*DEFINE_CURVE +999 +1.0e-03 +2.0e-03 +3.0e-03 +4.0e-03 +*DEFINE_CURVE +980 +13.5,0.0 +13.0,0.0 +5.0,0.0 +3.0,0.0 +2.5,0.0 +2.0,0.0 +1.0,0.0 +*CONTROL_FORMING_OUTPUT +$ -------1---------2---------3---------4---------5---------6---------7---------8 +$ CID NOUT TBEG TEND Y1/LCID Y2/CIDT + 1116 0 &clstime &endtime -980 -999 + 1117 0 &clstime &endtime -980 -999 + 1118 0 &clstime &endtime -980 -999 + 1119 0 &clstime &endtime -980 -999 +Revision information: +This feature is available starting from LS-DYNA Revision 74957. Other options’ +availabilities are as follows: +7. Y1/LCID is available from Revision 81403. +8. The scale factor SFO for ordinate values in *DEFINE_CURVE is supported from +Revision 82755. +9. Output for multiple tools is available from Revision 83090. +10. Support for arbitrary BIRTH and DEATH in *BOUNDARY_PRESCRIBED_MO- +TION_RIGID is available from Revision 83090. +11. The INTFOR option is available from Revision 83757. +12. Y2/CIDT is available from Revision 110091. +13. Negative abscissa in the LCID is available starting from Revision 112604. +Time = 0.0051966 +Time = 0.01366 +Binder closing +Punch home +Figure 12-35. An air draw example with closing and drawing. +Flanging steel #4 +Flanging steel #3 (hidden behind) +Flanging steel #2 +Upper pressure pad +Flanging steel #1 +Figure 12-36. An example of multiple flanging process. +Distance to home - &flg4pid: +23.0 +15.0 +13.0 +19.0 +13.5 +5.0 +3.0 +2.5 +2.0 +1.0 +&flg1pid +&flg2pid +&flg3pid +&flg4pid +) +( +30 +25 +20 +15 +10 +0.0 +0.002 +0.004 +0.006 +0.008 +&endtime +Explicit time (sec.) + Figure 12-37. D3PLOT/INTFOR output in case of multiple flanging process. +*CONTROL_FORMING_PARAMETER_READ +Purpose: This feature allows for reading of a numerical number from an existing file +and store in a defined parameter. The parameter can be used and referred in the +current simulation. The file to be read may be a result from a previous simulation. The +file may also simply contain a list of numbers defined beforehand and to be used for the +current simulation. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +FILENAME +C +Parameter Cards. Include one card for each parameter. The next “*” card terminates +the input. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable PARNAME METHOD +LINE # +BEGIN +END +Type +C +Default +none +I +0 +I +0 +I +0 +I +0 + VARIABLE +DESCRIPTION +FILENAME +Name of the file to be read. +PARNAME +Parameter name. Maximum character length: 7. +METHOD +Read instruction: +EQ.1: read, follow definition by LINE#, BEGIN and END +definition +LINE # +Line number in the file. +BEGIN +Beginning column number in the line number defined above. +END +Ending column number in the line number defined above. +Remarks: +1. Keyword input order is sensitive. Recommended order is to define variables in +*PARAMETER first, followed with this keyword, using the defined variables. +2. Multiple variables can be defined with one such keyword, with the file name +needed to be defined only once. If there are variables located in multiple files, +the keyword needs to be repeated for each file. +3. An example provided below shows that multiple PIDs for individual tools and +blank are defined in files “data.k” and “data1.k”. In the main input file +“sim.dyn” used for LS-DYNA execution, variables (integer) are first initialized +for PIDS of all tools and blank with *PARAMETER. These variables are updat- +ed with integers read from files “data.k” and “data1.k” from respective line +number and column number through the use of this keyword. In the *SET_- +PART_LIST definition, these PIDs are used to define the part set. +Below is file “data.k”, to be read into “sim.dyn:: +$$$$$$$$$$$$$$$$$$$$$$$$$ +$$$ define PIDs +$$$$$$$$$$$$$$$$$$$$$$$$$ +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+-- +upper die pid: 3 +lower post pid: 2 +Below is file “data1.k”, also to be read into “sim.dyn”: +$$$$$$$$$$$$$$$$$$$$$$$$$ +$$$$$$$$$$$$$$$$$$$$$$$$$ +$$$$$$$$$$$$$$$$$$$$$$$$$ +$$$ define PIDs +$$$$$$$$$$$$$$$$$$$$$$$$$ +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+-- +lower binder pid: 4 +blank pid: 1 +Below is partial input for the main input file “sim.dyn”: +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+-- +*INCLUDE +blank.k +*INCLUDE +tool.k +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+-- +*PARAMETER +Iblankp,0 +Iupdiep,0 +Ipunchp,0 +Ilbindp,0 +Rblankmv,0.0 +Rpunchmv,0.0 +Rupdiemv,0.0 +Rbindmv,0.0 +Rbthick,1.6 +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+-- +*CONTROL_FORMING_PARAMETER_READ +data.k +updiep,1,5,30,30 +punchp,1,6,30,30 +*CONTROL_FORMING_PARAMETER_READ +data1.k +lbindp,1,7,30,30 +blankp,1,8,30,30 +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+-- +*SET_PART_LIST +1 +&blankp +*SET_PART_LIST +2 +&punchp +*SET_PART_LIST +3 +&updiep +*SET_PART_LIST +4 +&lbindp +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+-- +*CONTROL_FORMING_AUTOPOSITION_PARAMETER_SET +$# psid cid dir mpsid position premove thick parname + 1 0 3 2 1 0.000 &bthick blankmv + 3 0 3 1 1 0.000 updiemv + 4 0 3 1 -1 0.000 bindmv +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+-- +*PART_MOVE +$pid,xmov,ymov,zmov,cid,ifset +1,0.0,0.0,&blankmv,,1 +3,0.0,0.0,&updiemv,,1 +4,0.0,0.0,&bindmv,,1 +4. This feature is available in LS-DYNA R5 Revision 55035 and later releases. +*CONTROL_FORMING_POSITION +Purpose: This keyword allows user to position tools and a blank in setting up a +stamping process simulation. All tools must be pre-positioned at their home positions. +For tools that are positioned above the sheet blank (or below the blank) and ready for +forming, *CONTROL_FORMING_TRAVEL should be used. This keyword is used +together with *CONTROL_FORMING_USER. One *CONTROL_FORMING_POSI- +TION card may be needed for each part. +NOTE: This option has been deprecated in favor of *CON- +TROL_FORMING_AUTOPOSITION_PARAME- +TER). +Positioning Cards. For each part to be positioned include an additional card. The next +“*” card terminates the input. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID +PREMOVE TARGET +Type +I +F +Default +none +none +I +I + VARIABLE +DESCRIPTION +PID +Part ID of a tool to be moved, as in *PART +The distance to pre-move the tool, in the reverse direction of +forming. +Target tool PID, as in *PART. The tool (PID) will be moved in the +reverse direction of the forming and positioned to clear the +interference with the blank, then traveled to its home position +with a distance GAP (*CONTROL_FORMING_USER) away from +the TARGET tool to complete the forming. +PREMOV +TARGET +Remarks: +When this keyword is used, all stamping tools must be in their respective home +positions, which is also the position of each tool at its maximum stroke. From the home +position each tool will be moved to its start position, clearing interference between the +blank and tool yet maintaining the minimum separation needed to avoid initial +penetration. Currently the tools can only be moved and travels in the direction of the +global Z-axis. +A partial keyword example is provided in manual pages under *CONTROL_FORM- +ING_USER. +Revision information: +This feature is available starting in Revision 24641. +*CONTROL_FORMING_PRE_BENDING +Purpose: This keyword allows for a pre-bending of an initially flat sheet metal blank, +typically used in controlling its gravity loaded shape during sheet metal forming. + Card 1 +1 +2 +Variable +PSET +RADIUS +Type +I +F +3 +VX +F +4 +VY +F +5 +VZ +F +6 +XC +F +7 +YC +F +8 +ZC +F +Default +none +none +none +none +none +none +none +none + VARIABLE +DESCRIPTION +PSET +Part set ID to be included in the pre-bending. +RADIUS +Radius of the pre-bending. +GT.0.0: bending center is on the same side as the element +normals +LT.0.0: bending center is on the reverse side of the element +normals. +See figure below for more information. +VX, VY, VZ +XC, YC, ZC +Vector components of an axis about which the flat blank will be +bent. +X, Y, Z coordinates of the center of most-bent location. If +undefined, center of gravity of the blank will be used as a default. +About pre-bending for gravity: +In some situation, a flat blank upon gravity loading will result in a “concave” shape in a +die. This mostly happens in cases where there is little or no punch support in the +middle of the die cavity and in large stamping dies. Although the gravity loaded blank +shape is correct the end result is undesirable. In these conditions, buckles may result +during the ensuing closing and forming simulation. In reality, a true flat blank rarely +exists. Typically, the blank is either manipulated (shaking or bending) by die makers in +the tryout stage, or by suction cups in a stamping press, to get an initial convex shape +prior to the binder closing and punch forming. This keyword allows this bending to be +performed. +*CONTROL_FORMING_PRE_BENDING +A partial keyword example (NUMISHEET2022 fender outer) is provided below, where +blank part set ID variable &BLKSID is defined previously, is to be bent in a radius value +of -10000.0mm, with the bending axis of Z, located on the reverse side of the blank +positive normal (Figure 12-38). The bending is off gravity center at x = 234.0, y = 161.0, +z = 81.6 (to the right along positive X-axis). Only a slight pre-bending on the blank is +needed to ensure a convex gravity-loaded shape. +*KEYWORD +⋮ +*CONTROL_IMPLICIT_FORMING +1 +*CONTROL_FORMING_PRE_BENDING +$ PSET RADIUS VX VY VZ XC YC ZC + &BLKSID -10000. 0.00 0.00 1.0 234.000 161.000 81.60 +... +*END +In Figures 12-39, initial blank shape without pre-bending is shown. Without pre- +bending, the gravity loaded blank sags in the middle of the die cavity, Figure 12-40, +which is likely unrealistic, and would lead to predictions of surface quality issues. With +pre-bending applied, Figure 12-41, blank bends slight and in convex shape before +loading. This shape results in an overall convex shape after gravity completes loading +(Figure 12-42), leading to a much shorter binder closing distance, and a more realistic +surface quality assessment. +Revision information: +This feature is available in double precision LS-DYNA Revision 66094 and later releases. +It is also available in LS-PrePost4.0 eZ-Setup for metal forming application (http://- +ftp.lstc.com/anonymous/outgoing/lsprepost/4.0/metalforming/). +Sheet blank +normal direction +Bending axis +Figure 12-38. Negative “R” puts center of bending on the opposite side of the +positive blank normal. +Sheet blank +Lower binder +Lower punch +Figure 12-39. Initial model before auto-positioning. +Blank sags in +the die cavity +Gravity loaded +sheet blank +Figure 12-40. Gravity loaded blank without using this keyword. +Sheet blank pre-bent with R=10000 mm +Figure 12-41. Pre-bending using this keyword (1st state of D3plots). +Gravity loaded on +pre-bensheet blank + Figure 12-42. Gravity loaded shape (last state of D3plots) with convex shape. +*CONTROL_FORMING_PROJECTION +Purpose: To remove initial penetrations between the blank and the tooling (shell +elements only) by projecting the penetrated blank (slave) nodes along a normal +direction to the surface of the blank with the specified gap between the node and the +tooling surface. This is useful for line die simulation of the previously formed panel to +reduce tool travel therefore saving simulation time. +Define Projection Card. This card may not be repeated. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IDPS +IDPM +GAP +NRSST +NRMST +Type +I +I +F +I +I +Default + VARIABLE +DESCRIPTION +IDPS +IDPM +GAP +Part ID of the blank (slave side). +Part ID for the tool (master side). +A distance, which defines the minimum gap required. +NRSST +Normal direction of the blank: +EQ.0: the normal to the surface of the blank is pointing towards +the tool, +EQ.1: the normal to the surface of the blank is pointing away +from the tool. +NRMST +Normal direction of the tool: +EQ.0: the normal to the surface of the tool is pointing towards +the blank, +EQ.1: the normal to the surface of the tool is pointing away +from blank. +Remarks: +This feature requires consistent normal vectors for both the rigid tooling surface and the +blank surface. +*CONTROL_FORMING_PROJECTION +This feature is available starting in Revision 25588. +*CONTROL_FORMING_REMOVE_ADAPTIVE_CONSTRAINTS +Purpose: This keyword converts an adaptive mesh into a fully connected mesh. +Adaptive constraints are removed and triangular elements are used to connect the +mesh. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID +Type +Default +I +0 + VARIABLE +PID +Remarks: +DESCRIPTION +Part ID (as in *PART) of the part whose adaptive mesh +constraints is to be removed and its mesh converted into +connected meshes. +In some application in sheet metal forming, such as stoning or spirngback simulation, +adaptive refinement on the sheet blank may affect the accuracy of the calculation. To +avoid this problem, non-adapted mesh is required. However, adaptively refined mesh +has the optimal mesh density that is tailored to the tooling geometry; the resulting +mesh, in its initial shape, either flat or deformed, has fewer elements (than a blank with +non-adapted and uniformly-sized elements) and thus is the most efficient for +simulation. If the parameter IOFLAG in *CONTROL_ADAPTIVE is turned on, such a +mesh adapt.msh will be generated at the end of each simulation, with its shape +conforming to the initial input blank shape. +This keyword takes the adapted mesh, removes the adaptive constraints, and use +triangular elements to connect the otherwise disconnected mesh. The resulting mesh is +a fully connected mesh, with the optimal mesh density, to be used to rerun the +simulation (without mesh adaptivity) for a better accuracy. +Note that the original adapt.msh file from a LS-DYNA run will include not only the +blank but the tooling mesh as well. In order to be used for this keyword, the original +file can be read into LS-PrePost, with blank shown in active display only, and menu +option File → Save As → Save Active Keyword As can be used to write out the adapted +blank mesh only. +*CONTROL_FORMING_REMOVE_ADAPTIVE_CONSTRAINTS +The following complete input file converts an adaptive mesh file blankadaptmsh.k +(Figure 12-43 left) with the PID of 1 into a connected mesh (Figure 12-43 right). The +resulting mesh will be in the dynain file. +*KEYWORD +*INCLUDE +blankadaptmsh.k +*PARAMETER +I blkpid 1 +$--------1---------2------- +*CONTROL_TERMINATION +0.0 +*CONTROL_FORMING_REMOVE_ADAPTIVE_CONSTRAINTS +$ PID +&blkpid +*set_part_list +1 +&blkpid +*INTERFACE_SPRINGBACK_LSDYNA_NOTHICKNESS +1 +*INTERFACE_SPRINGBACK_EXCLUDE +INITIAL_STRAIN_SHELL +INITIAL_STRESS_SHELL +*PART +$ PID SID MID + &blkpid 1 1 +*MAT_037 +... +*SECTION_SHELL +$ SECID ELFORM SHRF NIP + 1 2 0.000E+00 3 +1.0,1.0,1.0,1.0 +*END +Original mesh: adapt.msh +Modified, fully connected +mesh: dynain +Figure 12-43. Converting an adaptive mesh to a fully connected mesh. +Revision information: +This feature is available starting from LS-DYNA Revision 108157, in both SMP, MPP, +single and double precision. +*CONTROL_FORMING_SCRAP_FALL +Purpose: This keyword allows for direct and aerial trimming of a sheet metal part by +trim steels in a trim die. According to the trim steels and trim vectors defined, the sheet +metal part will be trimmed into a parent piece and multiple scrap pieces. The parent +piece is defined as a fixed rigid body. Trimmed scraps (deformable shells) are +constrained along trim edges until they come into contact with the trim steel; the edge +constraints are gradually released as the trim steel’s edge contacts the scrap piece, +allowing for contact-based scrap fall simulation. This keyword applies to shell elements +only. +Include Card 1 columns 1-6 only per each scarp piece for the constraint release method +. For the scrap trimming method include one set of Cards 1, 2 and 3 per +trim steel. The next “*” card terminates the input. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID +VECTID +NDSET +LCID +DEPTH +DIST +IDRGD +IFSEED +Type +I +I +I +I +F +F +I +I +Default +none +none +none +none +none +none +none +none + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NOBEAD +SEEDX +SEEDY +SEEDZ +EFFSET +GAP +IPSET +EXTEND +Type +I +F +F +F +F +F +I +F +Default +none +none +none +none +none +none +none +none + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NEWID +Type +I +Default +none +VARIABLE +PID +VECTID +NDSET +DESCRIPTION +Part ID of a scrap piece. This part ID becomes a dummy ID if +all trimmed scrap pieces are defined by NEWID. See definition +for NEWID and Figure 12-46. +Vector ID for a trim steel movement, as defined by *DEFINE_- +VECTOR. If left undefined (blank), global 𝑧-direction is +assumed. +A node set consists of all nodes along the cutting edge of the +trim steel. Note that prior to Revision 90339 the nodes in the +set must be defined in consecutive order. See Remarks (LS- +PrePost) below on how to define a node set along a path in LS- +PrePost. This node set, together with VECTID, is projected to +the sheet metal to form a trim curve. To trim a scrap out of a +parent piece involving a neighboring trim steel, which also +serves as a scrap cutter, the node set needs to be defined for the +scrap cutter portion only for the scrap, see Figure 12-46. +LCID +Load curve ID governing the trim steel kinematics, as defined +by *DEFINE_CURVE. +DEPTH +DIST +IDRGD +GT.0: velocity-controlled kinematics +LT.0: displacement-controlled kinematics +An example input deck is provided below. +A small penetrating distance between the cutting edge of the +trim steel and the scrap piece, as shown in Figure 12-45. Nodes +along the scrap edge are released from automatically added +constraints at the simulation start and are free to move after +this distance is reached. +A distance tolerance measured in the plane normal to the trim +steel moving direction, between nodes along the cutting edge +of the trim steel defined by NDSET and nodes along an edge of +the scrap, as shown in Figure 12-44. This tolerance is used to +determine if the constraints need to be added at the simulation +start to the nodes along the trim edge of the scrap piece. +Part ID of a parent piece, which is the remaining sheet metal +after the scrap is successfully trimmed out of a large sheet +metal. Note the usual *PART needs to be defined somewhere +in the input deck, along with *MAT_20 and totally fixed +translational and rotational DOFs. See Figure 12-46. +VARIABLE +DESCRIPTION +IFSEED +A flag to indicate the location of the scrap piece. +EQ.0: automatically determined. The trim steel defined +will be responsible to trim as well as to push (have +contact with) the scrap piece. +EQ.1: automatically determined, however, the trim steel in +definition will only be used to trim out the scrap, not +to push (have contact with) the scrap piece. +EQ.-1: user specified by defining SEEDX, SEEDY, and +SEEDZ +A node set to be excluded from initially imposed constraints +after trimming. This node set typically consists of nodes in the +scrap draw bead region where due to modeling problems the +beads on the scrap initially interfere with the beads on the rigid +tooling; it causes scrap to get stuck later in the simulation if left +as is. See Figure 12-47. +NDBEAD +SEEDX, SEEDY, +SEEDZ +𝑥, 𝑦, 𝑧 coordinates of the seed node on the scrap side; define +only when IFSEED is set to “-1”. See Figure 12-46. +EFFSET +GAP +IPSET +Scrap edge offset amount away from the trim steel edge, +towards the scrap seed node side. This is useful to remove +initial interference between the trimmed scrap (because of +poorly modeled trim steel) and coarsely modeled lower trim +post. See Figure 12-46. +Scrap piece offset amount from the part set defined by IPSET +(e.g. top surfaces of the scrap cutters), in the direction of the +element normals of the IPSET. This parameter makes it easier +to remove initial interference between the scrap and other die +components. See Figure 12-48. +A part set ID from which the scrap will be offset to remove the +initial interference, works together only with GAP. The part +set ID should only include portions of tool parts that are +directly underneath the scrap (top surface portion of the tools). +The normals of the IPSET must point toward the scrap. The +parts that should belong to IPSET are typically of those +elements on the top surface of the scrap cutter, see Figure +12-48. +The Scrap piece +is +modeled as a deform- +able shell part; parent +piece does not need to +be modeled. +Trim +steel +Nodes along the edge of the trim +steel are defined in a sequentailly +ordered node set. +Constraints +automatically +are +generated during initilization for +the nodes in blue along the scrap +trim edge, according to DIST. +GAP > 0.5 × (scrap thickness ++ shell thickness of trim post) +Trim +post +Trim line +DIST +Figure 12-44. Modeling details of the constraint release method. Drawing +modified from the original sketches courtesy of the Ford Motor Company. + VARIABLE +EXTEND +NEWID +Background: +DESCRIPTION +An amount to extend a trim steel’s edge based on the NDSET +defined, so it can form a continuous trim line together with a +neighboring trim steel, whose edge may also be extended, to +trim out the scrap piece. See Figure 12-46. +New part ID of a scrap piece for the scrap area defined by the +seed location. If this is not defined (left blank) or input as “0”, +the scrap piece will retain original PID as its part ID. See +Figure 12-46. This is useful in case where one original scrap is +trimmed into multiple smaller pieces, and contacts between +these smaller pieces need to be defined. +Sheet metal trimming and the resulting scrap fall are top factors in affecting the +efficiency of stamping plants worldwide. Difficult trimming conditions, such as those +multiple direct trims, a mixture of direct and cam trims, and multiple cam trims +involving bypass condition, can cause trimmed scraps to get stuck around and never +separate from the trim edge of the upper trim steels or lower trim post. Inappropriate +design of die structure and scrap chute can slow down or prevent scraps from tumbling +out to the scrap collectors. Smaller scrap pieces (especially aluminum) can sometimes +shoot straight up, and get stuck and gather in areas of the die structure. All these +problems result in shutdowns of stamping presses, reducing stroke-per-minute (SPM) +and causing hundreds of thousands of dollars in lost productivity. +With this keyword, engineers can consider the trimming details, manage the scrap trim +and the drop energy, study different trimming sequences, explore better die structure +and scrap chutes design and layout before a trim die is even built. This feature is +developed in conjunction with the Ford Motor Company. +The constraint release method: +Prior to Revision 91471 , simulating the scrap trim and fall uses the +“constraint release” method, where only the scrap piece is modeled and defined. +As shown in Figure 12-44, the scrap piece is modeled as a deformable body and the trim +steel and trim post as rigid shell elements, while the parent piece does not need to be +modeled at all. Between the trim edge of the scrap piece and the post there should be a +gap (indicated by GAP in the figure). The gap ensures that the contact interface (to be +explained later) correctly accounts for the shell thickness along the edge. A gap that is +too small may cause initial penetration between the scrap and the post which may +manifest as unphysical adhesion between the scrap and the post. +The Scrap piece +Trim +steel +Cutting Tolerance. When a +portion of the trim steel +comes within DEPTH of +a constrained node, the +constraint is released. In +the above schematic the tolerance is +indicated by the highlighted region. +Constraint release (final). Last contacted node +along the trim line gets released last from the +constraints. +Trim line +Trim +post +Constraint release (start). First node in contact is the first +released from constraints. The motion of the trim steel is +carried onto the scrap piece by the contact interface. +Figure 12-45. Contact-based separation and contact-driven kinematics and +dynamics in the constraint release method. Drawing modified from the original +sketches courtesy of the Ford Motor Company. +The edge of the scrap piece should initially be flush with that of the trim post +(perpendicular to the trim direction), just as exactly what happens in the production +environment. If the scrap is unrealistically positioned above the trim post edge, the +scrap may be permanently caught between the trim steel and the post under a +combination of uncertain trimming forces as the trim steel moves down. +During initialization, constraints are added automatically on the nodes along the scrap +trim edge corresponding to the node set (NDSET) along the trim steel, based on the +supplied tolerance variable DIST and trim vector VECTID. Although the direction of +the path is not important, prior to Revision 90339, the NDSET must be arranged so that +the nodes are in a sequential order (LS-PrePost 4.0 creating node set by path). As the +edge of the trim steel comes within DEPTH distance of the trim line, the constraints are +removed. The contact interfaces serve to project the motion of the trim steel onto the +scrap piece, see Figure 12-45. +The scrap trimming method: +The original simplified method has the following drawbacks: +1. No scrap trimming – the scrap piece cannot be trimmed directly from a parent +piece; an exact scrap piece after trimming must be modeled. +2. Poorly (or coarsely) modeled draw beads in the scrap piece do not fit properly +in badly modeled draw beads on the tooling, resulting in initial interferences +between the two and therefore affecting the simulation results. +3. For poorly (or coarsely) modeled scrap edges and trim posts, users have to +manually modify the scrap trim edges to clear the initial interference with the +trim posts. +4. Users must clear all other initial interferences (e.g. between scrap and scrap +cutter) manually. +Based on users’ feedback, a new method “scrap trimming” (after Revision 91471) has +been developed to address the above issues and to, furthermore, reduce the effort +involved in preparing the model. The new method (Figure 12-46) involves trimming +scrap from an initially large piece of sheet metal, leaving the parent piece as a fixed +rigid body. The trim lines are obtained from the trim steel edge node set NDSET and +the trim vector VECTID. +Parameters related to the constraint release method: +1. The value of DEPTH is typically set to one-half of the scrap thickness. +2. The initial gap separating the scrap from the post must be greater than the +average of the scrap and post thickness values, see Figure 12-44. +3. The input parameter DIST should be set larger than the maximum distance +between nodes along the trim steel edge and scrap edge in the view along the +trim direction, see Figure 12-44. +Parameters related to the scrap trimming method: +4. Similar to DEPTH, EFFSET should be typically set to one-half of the scrap +thickness, although it may be larger for some poorly modeled trim steels and +trim posts. +Contact: +Only *CONTACT_FORMING contact interfaces are allowed for contact between the +scrap piece and the trim steel. In particular, *CONTACT_FORMING_SURFACE_TO_- +SURFACE is recommended. A negative contact offset must be used; this is done +typically by setting the variable MST in *CONTACT_FORMING_SURFACE_TO_SUR- +FACE to the negative thickness value of the scrap piece. +For contact between the scrap piece and the shell elements in all the other die +structures, *CONTACT_AUTOMATIC_GENERAL should be used for the edge-to-edge +contact frequently encountered during the fall of the scrap piece. All friction +coefficients should be small. The explicit time integrator is recommended for the +modeling of scrap trim and fall. Mass scaling is not recommended. +LS-PrePost: +The node set (NDSET) defined along the trim steel edge can be created with LS-PrePost +4.0, via Model/CreEnt/Cre, Set Data, *SET_NODE, ByPath, then select nodes along the +trim edge continuously until finish and then hit Apply. +Keyword examples – the constraint release method: +A partial example of using the keyword below includes a node set ID 9991 along the +trim steel (PID 2) edge used to release the constraints between the scrap piece with PID +1, and the parent piece. The LCID for the trim steel kinematics is (+)33 (load curve is +controlled by velocity) moving in –Z direction. The trimming velocity is defined as +1000 mm/s and the retracting velocity is 4000 mm/s. The variables DEPTH and DIST +are set to 0.01 and 2.5, respectively. The contact interface between the trim steel and +scrap piece is defined using *CONTACT_FORMING_SURFACE_TO_SURFACE and +contact between the scrap and all other die structures are defined using *CONTACT_- +AUTOMATIC_GENERAL. +*KEYWORD +*CONTROL_TERMINATION +&endtime +*CONTROL_FORMING_SCRAP_FALL +$ PID VECTID NDSET LCID DEPTH DIST + 1 9991 33 0.75 2.0 +*SET_NODE_LIST + 9991 + 24592 24591 24590 24589 24593 24594 24595 24596 +*BOUNDARY_PRESCRIBED_MOTION_rigid +$pid,dof,vad,lcid,sf,vid,dt,bt +2,3,0,33,-1.0 +*DEFINE_CURVE +33 +0.0,0.0 +0.216,1000.0 +0.31,-4000.0 +0.32,0.0 +0.5,0.0 +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*CONTACT_forming_surface_to_surface_ID + 1 + 1 2 3 3 0 0 0 0 + 0.02 0.0 0.0 0.0 20.0 0 0.01.0000E+20 +$# sfs sfm sst mst sfst sfmt fsf vsf +0.0 0.0 0.0 &mst 1.0 1.0 1.0 1.0 +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*CONTACT_AUTOMATIC_GENERAL_ID + 2 +*END +For the negative option of LCID, displacement will be used as input to control the tool +kinematics. A partial example is provided below, where LCID is defined as a negative +integer of a load curve, controlling the trim steel kinematics. The trim steel is moving +down for 27.6075 mm in 0.2 sec to trim, and moving up for the same distance to its +original position in 0.3 sec to retract. Although this option is easier to use, the +corresponding velocity from the input time and displacement must be realistic for a +realistic simulation. +*CONTROL_FORMING_SCRAP_FALL +$ LCID<0: trimming steel kinematics is controlled by displacement. +$ PID VECTID NDSET LCID DEPTH DIST + 1 44 1 -33332 0.70 2.00 +*DEFINE_VECTOR +44,587.5,422.093,733.083,471.104,380.456,681.412 +*BOUNDARY_PRESCRIBED_MOTION_rigid_LOCAL +$pid,dof,vad,lcid,sf,vid,dt,bt +11,3,2,33332,1.0,44 +*DEFINE_CURVE +33332 +0.0,0.0 +0.2,-27.6075 +0.5,0.0 +A keyword example – the scrap trimming method: +The keyword example below shows three scrap pieces, with original PID &SPID1, new +PIDs 1001 and 1002, being trimmed out of a larger scrap &SPID1; the remaining parent +piece is defined as a fixed rigid body with PID 110. A different seed location is defined +separately for each scrap. The scraps &SPID1, 1001 and 1002 are each offset by 0.60mm +in the area of the seed location defined, in the direction normal to the elements defined +by IPSET 887, 888, and 889, respectively. The trim edge offset is 0.90mm for all scraps. +The draw bead node sets to be released are, 987, 988, 989 for each scrap as defined by +the corresponding seed locations. +*CONTROL_FORMING_SCRAP_FALL +$ PID VECTID NDSET VLCID DEPTH DIST IDRGD IFSEED + &spid1 &cord1 &nset1 1800 &depth1 2.00 110 -1 +$ NDBEAD seedx seedy seedz effset GAP IPSET EXTEND + 987 -528.046 373.40 710.000 0.90 0.60 887 8.0 + 0 + &spid1 &cord2 &nset2 1801 &depth1 2.00 110 -1 + 987 -528.046 373.40 710.000 0.90 0.60 887 8.0 + 0 + &spid1 &cord3 &nset3 1802 &depth1 2.00 110 -1 + 987 -528.046 373.40 710.000 0.90 0.60 887 8.0 + 0 +$ + &spid1 &cord3 &nset33 1802 &depth1 2.00 110 -1 + 988 -252.452 383.322 799.974 0.90 0.60 888 8.0 +1001 + &spid1 &cord4 &nset4 1803 &depth1 2.00 110 -1 + 988 -252.452 383.322 799.974 0.90 0.60 888 8.0 + 1001 + &spid1 &cord5 &nset5 1804 &depth1 2.00 110 -1 + 988 -252.452 383.322 799.974 0.90 0.60 888 8.0 + 1001 +$ + &spid1 &cord5 &nset55 1804 &depth1 2.00 110 -1 + 989 74.452 404.522 857.974 0.90 0.60 889 8.0 + 1002 + &spid1 &cord6 &nset6 1805 &depth1 2.00 110 -1 + 989 74.452 404.522 857.974 0.90 0.60 889 8.0 + 1002 + &spid1 &cord7 &nset7 1806 &depth1 2.00 110 -1 + 989 74.452 404.522 857.974 0.90 0.60 889 8.0 + 1002 +Revision/Other information: +A graphical user interface capable of setting up a complete input deck for the original +simplified method is now available in LS-PrePost 4.0 under APPLICATION/Scrap Trim +reference paper +(http://ftp.lstc.com/anonymous/outgoing/lsprepost/4.1/). +regarding the development and application of this keyword for the constraint release +method can be found in the proceedings of the 12th International LS-DYNA User's +Conference. The following provides a list of revision history for the keyword: + A +1. The constraint release method is available between LS-DYNA Revision 63618 and +91471. +2. The scrap trimming method is available starting in Revision 91471. +3. The parameter NEWID is available starting in Revision 92578. +4. The restriction of NDSET must be defined in a consecutive order is lifted +starting in Revision 90339. +IDRGD +Trim steel 1 +Trim steel 2 +NEWID2 +NEWID1 or PID +NEWID3 +Scrap cutter +Scrap seed node +EXTEND +EXTEND +IDRGD +NSET1 +Trim steel 1 +NEWID2 +EFFSET +NSET2 +SEEDX, Y, Z +Trim steel 2 +Figure 12-46. Trimming of multiple scraps and parameter definitions in the +scrap trimming method. Model courtesy of the Ford Motor Company. +NDBEAD +NDBEAD +Figure 12-47. Definition of NDBEAD in the scrap trimming method. Model +courtesy of the Ford Motor Company. +Scrap piece +Scrap cutter +top surface +Before trim +Scrap cutter side view +Element normals +Scrap piece: Normals should face the IPSET +GAP +IPSET: To get +the proper offset, elements +immediately below the scrap piece should be +separated into a different PID (and included in +the IPSET) from the vertical walls of the scrap +cutter. In addition, IPSET should have consistent +normals pointing toward the scrap piece. +After trim +Figure 12-48. Element normal of the IPSET in the scrap trimming method. +Model courtesy of the Ford Motor Company. +*CONTROL_FORMING_SHELL_TO_TSHELL +Purpose: This keyword is created to allow users to easily change the element type from +thin shell elements (*SECTION_SHELL) to thick shell elements (*SECTION_TSHELL), +and to generate segments on both top and bottom side of the thick shells. Note that +mesh adaptivity is also supported. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID +THICK +MIDSF +IDSEGB +IDSEGT +Type +I +I +I +I +I +Default +none +none +none +none +none + VARIABLE +DESCRIPTION +PID +Part ID of the thin shell elements. +THICK +Thickness of the thick shell elements (Tshell). +MIDSF +Tshell mid-plane position definition : +IDSEGB +MIDSF.EQ.0: Mid-plane is at thin shell surface. +MIDSF.EQ.1: Mid-plane is at one half of THICK above thin +shell surface. +MIDSF.EQ.-1: Mid-plane is at one half of THICK below thin +shell surface. +Set ID of the segments to be generated on the bottom layer of the +Tshells, which can be used for segment-based contact. The +bottom side of Tshells is the opposite side of the positive normal +side of the thin shells, see Figure 12-49. +Note the default normal of the generated segments are consistent +with the thin shells’ normal. To reverse this default normal, set +the IDSEGB to a negative number. +Under the FORMING type of contact, if the generated segments +are used as a slave member in contact with a master member of a +rigid body, the rigid body’s normals must be consistent and +facing the slave segments. Note that the slave segments normals +are not required to point at the rigid bodies, although they should +be made consistent. +IDSEGT +*CONTROL_FORMING_SHELL_TO_TSHELL +DESCRIPTION +Set ID of the segments to be generated on the top layer of the +Tshells, which can be used for segment-based contact. The top +side of a Tshells is the same side of the positive normal side of the +thin shells, see Figure 12-49. +Note the normal of the generated segments are consistent with +the thin shells’ normal. To reverse this default normal, set the +IDSEGT to a negative number. +Remarks: +This keyword will convert thin shell elements to thick shell elements. The position of +the thick shells’ mid-plane in reference to the thin shell’s surface is dependent on +MIDSF (Figure 12-49). Node IDs of the thick shell elements will be the same as those for +the thin shells. Element IDs of the thick shell elements will start at 2 (so renumber +element IDs of other PID accordingly). Only one layer of thick shells will be created. +New nodes generated adaptively from their parent nodes with *BOUNDARY_SPC are +automatically constrained accordingly. +This feature is developed as requested by JSOL Corporation. +Examples: +1)A standalone part of thin shell elements can be changed to thick shell elements +with a simplified small input deck. The following will convert shell elements +with PID 100 of thickness 1.5mm to thick shell elements of PID 100 with thick- +ness of 2.0mm, with thick shell meshes stored in a file “dynain.geo”. Note that +MIDSF, IDSEGB and IDSEGT cannot be used in this case. +*KEYWORD +*CONTROL_TERMINATION +0.0 +*INCLUDE +shellupr.k +*SET_PART_LIST +1, +100 +*PART +Sheet blank +100,100,100 +*SECTION_SHELL +$ SID ELFORM SHRF NIP PROPT + 100 2 0.833 3 1.0 +$ T1 T2 T3 T4 NLOC +1.5,1.5,1.5,1.5 +*MAT_037 +$# MID RO E PR SIGY ETAN R HLCID +100 7.8500E-9 2.1000E+5 0.333000 1.00 90905 +*DEFINE_CURVE + 90905 + 0.000000000E+00 0.380000000E+03 + 0.300000003E-02 0.392489226E+03 + 0.600000005E-02 0.403294737E+03 + 0.899999961E-02 0.412847886E+03 + 0.120000001E-01 0.421429900E+03 + 0.150000006E-01 0.429234916E+03 + 0.179999992E-01 0.436402911E+03 + 0.209999997E-01 0.443038343E+03 +*INTERFACE_SPRINGBACK_LSDYNA +1 +OPTCARD,,,1 +*CONTROL_FORMING_SHELL_TO_TSHELL +$ PID THICK + 100 2.0 +*END +that +2)The conversion can also be done in an input deck set up for a complete metal +forming simulation with thin shell elements as a sheet blank. The conversion +happens in the beginning of the simulation, as shown in an example below. +Only the keywords needed change are listed, commented out with $ signs and +replaced with appropriate cards for thick shells. The thin shell sheet blank with +PID 1 is to be converted to a thick shell sheet blank with thickness of 1.6mm, +noting +instead of +*SECTION_SHELL for the sheet blank. Corresponding material type for the +sheet blank (*MAT_037) also needs to be changed to a type that supports solid +element simulation (*MAT_024). The mid-plane of the thick shells will be one +half of 1.6 mm below the thin shells’ surface, with segment IDs 10 (IDSEGB) and +11 (IDSEGT) created on the bottom and top side of the thick shells, respectively, +as shown in Figure 12-49. IDSEGB 10 with SSTYP 0 is defined to contact with the +lower punch (part set ID 2) with MSTYP 2, and IDSEGT 11 with SSTYP 0 is used +for contact with the upper die cavity with part set ID of 3, of MSTYP 2. +should be defined +*SECTION_TSHELL +the +*KEYWORD +... +*PART +Sheet blank +1,1,1 +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +$ Blank property +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +$*SECTION_SHELL +$ SID elform SHRF nip PROPT QR/IRID ICOMP SETYP +$ 1 2 0.833 3 1.0 +$ T1 T2 T3 T4 NLOC +$&b1thick,&b1thick,&b1thick,&b1thick +*SECTION_TSHELL +$ SID elform SHRF nip PROPT QR/IRID ICOMP SETYP + 1 1 0.833 &nip 1.0 +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +$*MAT_037 +$ MID RO E PR SIGY ETAN R HLCID +$ 1 7.85E-09 2.07E+05 0.28 92 +*MAT_024 +$ MID RO E PR SIGY ETAN FAIL TDEL + 1 7.85E-09 2.07E+05 0.28 382.8 0.0 0.0 0.0 +$ C P LCSS LCSR VP +0.0 0.0 92 0 0.0 +$ EPS1 EPS2 EPS3 EPS4 EPS5 EPS6 EPS7 EPS8 +$ ES1 ES2 ES3 ES4 ES5 ES6 ES7 ES8 +*DEFINE_CURVE +92,,,0.5 + 0.0000000000E+00 3.8276000000E+02 + 4.0000000000E-03 3.9616000000E+02 +8.0000000000E-03 4.0695000000E+02 + ⋮ ⋮ +*INTERFACE_SPRINGBACK_LSDYNA +1 +OPTCARD,,,1 +*CONTROL_FORMING_SHELL_TO_TSHELL +$ PID THICK MIDSF IDSEGB IDSEGT + 100 1.6 -1 10 11 +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE +$ SSID MSID SSTYP MSTYP + 11 2 0 2 + ⋮ ⋮ ⋮ +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE +$ SSID MSID SSTYP MSTYP + 10 3 0 2 + ⋮ ⋮ ⋮ +... +*END +Revision information: +This feature is available in LS-DYNA starting in Revision 104903. The following +revisions indicate the Revision history of additional features: +1) Revision 106116: negative option of IDSEGB and IDSEGT. +2) Revision 106162: MIDSF, IDSETGB and IDSEGT becomes available. +3) Revision: 106217: automatically add *BOUNDARY_SPC for newly generated +nodes whose parent nodes are assigned with *BOUNDARY_SPC. +Thin shell +normals +Original sheet blank +with shell elements +Thin shell +surface +Created thick shells for +MIDSF=0 +Thick shell +mid-plane +THICK +THICK +THICK +Created thick shells for +MIDSF=1 +Thick shell +mid-plane +Created thick shells for +MIDSF=-1 +Thick shell +mid-plane +NUMISHEET'05 Cross member +Top segment ID 11 +(IDSEGT) +Bottom segment ID 10 +(IDSEGB) + Figure 12-49. Converting thin shells to thick shells in sheet metal forming +*CONTROL_FORMING_STONING +Purpose: This feature is developed to detect surface lows or surface defects formed +during metal stamping. This calculation is typically performed after a springback +simulation. A curvature-based method is implemented with the feature. Users have +the option to check an entire part or just a few local areas, defined by node set or shell +element set. In each area, direction of the stoning action can be specified by two nodes + or simply allow the program to automatically determine the +stoning direction. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ISTONE +LENGTH WIDTH +STEP +DIRECT REVERSE METHOD +Type +I +F +F +F +F +Default +none +0.0 +0.0 +0.0 +0.0 + Card 2 +1 +2 +3 +4 +Variable +NODE1 +NODE2 +SID +ITYPE +Type +Default +I +0 +I +0 +I +0 +I +0 +5 +V1 +F +0.0 +0.0 +0.0 +I +0 +6 +V2 +F +I +0 +7 +V3 +F +8 + VARIABLE +DESCRIPTION +ISTONE +Stoning calculation option. +EQ.1: calculate panel surface quality using stoning method. +LENGTH +Length of the stone. +WIDTH +Width of the stone. +STEP +Stepping size of the moving stone. +DIRECT +Number of automatically determined stoning direction(s). +VARIABLE +DESCRIPTION +REVERSE +Surface normal reversing option: +EQ.0: do not reverse surface normals. +EQ.1: reverse surface normals. +METHOD +Stoning method. +EQ.0: curvature-based method. +NODE1 +Tail node defining stoning moving direction. +NODE2 +Head node defining stoning moving direction. +SID +Node or shell set ID. +ITYPE +Set type designation: +EQ.1: node set +EQ.2: element set +V1, V2, V3 +Vector components defining stoning direction (optional). +About stoning: +Stoning is a quality checking process on class-A exterior stamping panels. Typically the +long and wider surfaces of an oil stone of a brick shape are used to slide and scratch in a +given direction against a localized area of concern on a stamped panel. Surface “lows” +are shown where scratch marks are not visible and “highs” are shown in a form of +scratch marks. This keyword is capable of predicting both the surface “lows” and +“highs”. Since stoning process is carried out after the stamping (either drawn or +trimmed) panels are removed from the stamping dies, a springback simulation needs to +be performed prior to conducting a stoning analysis. +Modeling guidelines: +As a reference, typical stone length and width can be set at 150.0 and 30.0 mm, +respectively. The step size of the moving stone is typically set about the same order of +magnitude of the element length. The smallest element length can be selected as the +step size. +The variable DIRECT allows for the automatic definition of the stoning directions. Any +number can be selected but typically 2 is used. Although CPU time required for the +stoning calculation is trivial, a larger DIRECT consumes more CPU time. +Stoning is performed on the outward normal side of the mesh. Element normals must +be consistent and oriented accordingly. Element normal can be automatically made +consistent in LS-PrePost4.0 under EleTol/Normal menu. Alternatively, the variable +REVERSE provides in the solver an easy way to reverse a part with consistent element +normals before the computation. +The variables NODE1 and NODE2 are used to define a specific stoning direction. The +stone is moved in the direction defined by NODE1 to NODE2. Alternatively, one can +leave NODE1 and NODE2 blank and define the number of automatically determined +stoning directions by using the variable DIRECT. Furthermore, stoning direction can +also be defined using a vector by defining the variables V1, V2, and V3. +The blank model intended for analysis can be included using keyword *INCLUDE. If +nothing is defined for SID and ITYPE then the entire blank model included will be used +for stoning analysis. +A large area mesh can be included in the input file. An ELSET must also be included, +which defines a local area that requires stoning computation. Alternatively, an ELSET +can define several local areas to be used for the computation. Furthermore, an ELSET +should not include meshes that have reversed curvatures. An ELSET can be easily +generated using LS-PrePost4.0, under Model/CreEnt/Cre/Set_Data/*SET_SHELL. +Since stoning requires high level of accuracy in springback prediction, it is +recommended that the SMOOTH option in keyword *CONTACT_FORMING_ONE_- +WAY_SURFACE_TO_SURFACE to be used during the draw forming simulation. Not +all areas require SMOOTH contact, only areas of interest may apply. In addition, +meshes in the areas of concern need to be very fine, with average element size of 1 to 2 +mm. Mesh adaptivity is not recommended in the SMOOTH/stoning areas. Also, mass +scaling with DT2MS needs to be sufficiently small to reduce the dynamic effect during +forming. For binder closing of large exterior panels, implicit static method using *CON- +TROL_IMPLICIT_FORMING type 2 is recommended, to further reduce potential +buckles caused by the inertia effect. +Stoning results/output: +It is recommended that double precision version of LS-DYNA be used for this +application. The output of the stoning simulation results is in a file named +“filename.output”, where “filename” is the name of the LS-DYNA stoning input file +containing this keyword, without the file extension. The stoning results can be viewed +using LS-PrePost4.0, under MFPost/FCOMP/Shell_Thickness. +Application example: +An example of a stoning analysis on a Ford Econoline door outer panel is provided for +reference. The original part model comes from National Crash Analysis Center at The +George Washington University. The original part was modified heavily in LS-PrePost4.0 +to fit the needs of the demonstration purpose. Binder and addendum were created and +sheet blank size was assumed. The blank is assigned 0.65mm thickness and a BH210 +properties with *MAT_037. Shell thickness contour plots for the drawn and trimmed +panels are shown in Figures 12-50 and 12-51, respectively. Springback amount in Z is +plotted in Figure 12-52. The complete input deck used for the stoning simulation is +provided below for reference; where, a local area mesh of the door handle after +springback simulation “Doorhandle.k” and an element set “elset1.k” are included in the +deck. Locations of the ELSETs are defined for the upper right (Figure 12-53 left) and +lower right corners (Figure 12-54 left) of the door handle, where “mouse ear” are +expected. +*KEYWORD +*TITLE +Stoning Analysis +*INCLUDE +Doorhandle.k +*INCLUDE +elset1.k +*CONTROL_FORMING_STONING +$ ISTONE LENGTH WIDTH STEP DIRECT REVERSE METHOD + 1 150.0 4.0 1.0 9 0 0 +$ NODE1 NODE2 SID ITYPE + 1 2 +*END +Stoning results are shown in Figures 12-53 (right) and 12-54 (right) for the upper right +and lower right corners, respectively. “Mouse ears” are predicted where anticipated. +Revision information: +The stoning feature is available in LS-DYNA Revision 54398 and later releases. Vector +component option is available in Revision 60829 and later releases. +Thickness (mm) +0.6818 +0.6649 +0.6480 +0.6310 +0.6141 +0.5972 +0.5803 +0.5634 +0.5464 +0.5295 +0.5126 +Figure 12-50. Thickness contour of the panel after draw simulation. +Thickness (mm) +0.6818 +0.6649 +0.6480 +0.6310 +0.6141 +0.5972 +0.5803 +0.5634 +0.5464 +0.5295 +0.5126 +Figure 12-51. Thickness contour of the panel after trimming. +Springback (mm) +0.6818 +0.6649 +0.6480 +0.6310 +0.6141 +0.5972 +0.5803 +0.5634 +0.5464 +0.5295 +0.5126 +Figure 12-52. Springback amount (mm). +A region where an "elset" +was selected for stoning +Stoning results: "mouse +ear" potential in the corner +Out-of-plane +displacement +(mm) +0.2336 +0.2103 +0.1869 +0.1636 +0.1402 +0.1166 +0.0935 +0.0070 +0.0467 +0.0234 +0.0000 +Figure 12-53. Stoning simulation for the upper right door corner. +Out-of-plane +displacement +(mm) +0.3580 +0.3222 +0.2864 +0.2506 +0.2148 +0.1790 +0.1432 +0.1074 +0.0716 +0.0358 +0.0000 +A region where another "elset" +was defined for stoning +Stoning results: "mouse ear" +potential in the corner +Figure 12-54. Stoning simulation for the lower right door corner. +*CONTROL_FORMING_TEMPLATE +Purpose: This keyword is used to simplify the required input for sheet metal stamping +simulations. With this keyword, five templates are given: three-piece air draw, three- +piece toggle draw, four-piece stretch draw, trimming, and springback. +NOTE: This option has been deprecated in favor of *CON- +TROL_FORMING_AUTOPOSITION_PARAME- +TER. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IDTEMP +BLKID +DIEID +PNCH +BNDU +BNDL +TYPE +PREBD +Type +I +I +I +I +I +I +Default +none +none +none +none +none +none +I +0 +F +0.0 +Remarks +1 + Card 2 +1 +2 +2 +3 +4 +5 +Variable +LCSS +AL/FE +R00 +R45 +R90 +Type +I +C +F +F +F +6 +E +F +7 +8 +DENSITY +PR +F +F +Default +none +Fe +1.0 +R00 +R00 +none +none +none + Card 3 +Variable +Type +1 +K +F +2 +N +F +3 +4 +5 +6 +MTYP +UNIT +THICK +GAP +I +F +F +8 +7 +FS +F +Default +none +none +37 +none +1.1t +0.1 +I +Card 4 +1 +2 +Variable +PATERN +VMAX +Type +Default +I +1 +F +1000 + Card 5 +1 +2 +3 +VX +F +0 +3 +4 +VY +F +0 +4 +5 +VZ +F +6 +7 +8 +VID +AMAX +I +F +-1 +none +1.0e+6 +5 +6 +7 +8 +Variable +LVLADA +SIZEADA TIMSADA +D3PLT +Type +Default +I +1 +F +I +I +none +20 +10 + VARIABLE +DESCRIPTION +IDTEMP +Type of forming process: +EQ.1: 3-piece air-draw (Figure 12-55) +EQ.2: 3-piece Toggle-draw (Figure 12-56) +EQ.3: 4-piece stretch draw (Figure 12-57) +EQ.4: Springback +EQ.5: Trimming +BLKID +Part or part set ID that defines the blank. +DIEID +Part or part set ID that defines the die. See Figures 12-55, 12-56 +and 12-57 for more information +PNCHID +Part or part set ID that defines the punch. +BNDUID +Part or part set ID that defines the upper binder. +BNDLID +Part or part set ID that defines the lower binder. +Upper die (cavity) +Blank +Punch +(post) +Lower +binder +Binder gap +(a) Positioning +(b) Binder closing +(c) Forming +Figure 12-55. IDTEMP = 1: forming in 3-piece air draw. +Upper +binder +Punch +(Post) +Blank +Lower die +(cavity) +Binder gap +(a) Positioning +(b) Binder closing +(c) Forming +Figure 12-56. IDTEMP = 2: forming in 3-piece toggle draw. + VARIABLE +TYPE +DESCRIPTION +Flag for part or part set ID used in the definition of BLKID, +DIEID, PNCHID, BNDUID, and BNDLID: +EQ.0: Part ID +EQ.1: Part set ID +PREBD +LCSS +“Pull-over” distance, for 4 piece stretch draw only. This is the +travel distance of both upper and lower binder together after they +are fully closed. Typically this distance is below 50mm. See +Figure 12-57 for more information. +If the material (*MAT_XXX) for the blank is not defined, this +curve ID will define the stress-strain relationship; otherwise, this +curve is ignored. +Upper +punch +Blank +Lower die +(cavity) +Upper +binder +Lower +binder +Binder +gap +PREBD +(a) Positioning +(b) Binder closing +(c) Pull-over +(d) Upper closing +(e) Draw home +Figure 12-57. IDTEMP = 3: forming in 4-piece stretch draw. + VARIABLE +AL/FE +DESCRIPTION +This parameter is used to define the Young’s Modulus and +density of the blank. If this parameter is defined, E and DENSITY +will be defined in the units given by Table 12-58. +EQ.A: the blank is aluminum +EQ.F: the blank is steel (default) +R00, R45, +R90 +Material anisotropic parameters. For transversely anisotropy the +R value is set to the average value of R00, R45, and R90. +E +Young’s Modulus. If AL/FE is user defined, E is unnecessary +DENSITY +Material density of blank. If AL/FE is user defined, this +parameter is unnecessary +PR +K +Poisson’s ratio. +Strength coefficient for exponential hardening (𝜎̅̅̅̅̅ = 𝑘𝜀̅ 𝑛). If LCSS +is defined, or if a blank material is user defined by *MAT_XXX, +this parameter is ignored. +VARIABLE +DESCRIPTION +N +MTYP +UNIT +THICK +GAP +Exponent for exponential hardening (𝜎̅̅̅̅̅ = 𝑘𝜀̅ 𝑛). If LCSS is +defined, or if a blank material user defined, this parameter is +ignored. +Only material models *MAT_036 and *MAT_037 are supported. +Define a number between 1 and 10 (Table 12-58) to indicate the +UNIT used in this simulation. This unit is used to obtain proper +punch velocity, acceleration, time step, and material properties. +Blank thickness. If the blank thickness is already defined with +*SECTION_SHELL, this parameter is ignored. +The gap between rigid tools at their home position. If *BOUND- +ARY_PRESCRIBED_RIGID_BODY is user defined, this parameter +is ignored. The default is 1.1 x blank thickness. +FS +Friction coefficient (default = 0.10). If the contact (*CONTACT) is +user defined, this parameter is ignored. +PATERN +Velocity profile of moving tool. If the velocity is user defined by +*BOUNDARY_PRESCRIBED_RIGID_BODY, PATERN is ignored. +EQ.1: Ramped velocity profile +EQ.2: Smooth velocity curve +VX, VY, VZ +Vector components defining +the direction of +movement. The default direction is defined by VID. +the punch +VID +Vector ID defining the direction of the punch movement. This +variable overrides the vector components (VX, VY, VZ). If VID +and (VX, VY, VZ) are undefined, the punch is assumed to move +in the negative z-direction. +AMAX +The maximum allowable acceleration. +LVLADA +Maximum adaptive level. +SIZEADA +Minimum element size permitted in the adaptive mesh. +TIMSADA +Total number of adaptive steps during the forming simulation. +D3PLT +The total number of output states in the D3PLOT database. +*CONTROL_FORMING_TEMPLATE +UNIT +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +Mass +Ton +Gm +Gm +Gm +Gm +Kg +Kg +Kg +Kg +Kg +Length Mm Mm Mm +Cm +Cm Mm +Cm +Cm +Cm +Time +Force +S +N +Ms +S +Us +S +Ms +Us +Ms +S +N +𝜇N +1e7N Dyne KN +1e10N 1e4N 1e- +2N +m +S +N +Table 12-58. Available units for metal stamping simulation. +About IDTEMP: +When the variable IDTEMP is set to 1, it represents a 3-piece draw in air, as shown in +Figure 12-55. When IDTEMP is set to 2, a 3-piece toggle draw is assumed, Figure 12-56. +For IDTEMP of 1 or 2, LS-DYNA will automatically position the tools and minimize the +punch travel (step a), calculate the binder and punch travel based on the blank +thickness and the home gap (step b), set the termination time based on step (a) and (b), +define the rigid body motion of the tooling, establish all the contacts between the blank +and rigid tools, and, select all necessary control parameters. +When IDTEMP is set to 3, a 4-piece stretch draw shown in Figure 12-57 will be +followed. The die action goes as follows: after upper binder moves down to fully close +with lower binder, both pieces move together down a certain distance (usually ~50mm) +to “pull” the blank “over” the lower die, then upper punch closes with the lower die, +finally the binders move down together to their home position. +Both toggle draw and 4-piece stretch draw are called “double action” processes which +suffer from a slower stamping speed. As the metric of “hits per minute” (or “parts per +minute”) becomes a stamping industry benchmark for efficiency, these types of draw +are becoming less popular (especially the 4-piece stretch draw). Nevertheless, they +remain important stamping processes for controlling wrinkles in difficult-to-form +panels such as lift gate inners, door inners and floor pans. These two processes are also +used in situation where deep drawn panels require draw depth of over 250mm, the +usual limit for automatic transfer presses. +For all the above IDTEMP values, users do not need to define additional keywords, +such as *PART, *CONTROL, *SECTION, *MAT_…, *CONTACT_… (drawbead +definition is an exception), and, *BOUNDARY_PRESCRIPTION_RIGID, etc. If any such +keyword is defined, automatic default settings will be overridden. +When IDTEMP is set to 4, springback Simulation will be conducted. The only +additional keyword, *BOUNDARY_SPC_… is needed to specify the constraints in the +input deck. +When IDTEMP is set to 5, a trimming operation will be performed. The only additional +keyword, *DEFINE_CURVE_TRIM, is needed to specify the trim curves in the input +deck. +Revision information: +This feature is available starting in Revision 45901 and later releases. +*CONTROL_FORMING_TIPPING +Purpose: This keyword is developed to reorient or reposition a part between the +stamping dies. In stamping line die simulation, panel tipping and translation between +the die stations are frequently required. Typically such transformation involves only a +small amount of rotations, e.g. < 15 degrees; and some large amounts of translation. For +example, there could be a tipping angle of 10 degree along Y-axis and a translation of +2000 mm along the X-axis between the current trimming die and next flanging die. +Card Set. For each rotated or translated part or set add a Tipping Card plus NMOVE +Move Cards. The data set for this keyword ends at the next keyword (“*”) card. +Tipping Card. Specify a part or set ID to be tipped. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID/SID +ITYPE +ISTRAIN +IFSTRSS +NMOVE +Type +I +I +Default +none +none +I +0 +I +0 +I +0 +Move Card (Rot). Format when first entry, ROT/TRAN, is set to 1. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable ROT/TRAN +V11 +V12 +V13 +X01 +Y01 +Z01 +DISTA1 +Type +I +F +F +F +F +F +F +F +Default +none +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Move Card (Trans). Format when first entry, ROT/TRAN, is set to 2. +5 +6 +7 +8 + Card 2 +1 +2 +Variable ROT/TRAN +DX +Type +I +F +3 +DY +F +4 +DZ +F +Default +none +0.0 +0.0 +0.0 + VARIABLE +PID/SID +DESCRIPTION +Part ID or part set ID of part(s) that requires tipping and/or +translation. +ITYPE +Part ID or part set ID indicator: +EQ.1: PID means part ID, +EQ.2: PID/SID means part set ID. +ISTRAIN +Strain tensors inclusion option: +EQ.1: include in tipping/translation. +ISTRESS +Stress tensors inclusion option: +EQ.1: include in tipping/translation. +NMOVE +Total number of tipping and translation intended with this +keyword. +ROT/TRAN +Transformation type: +EQ.1: rotation, +EQ.2: translation. +V11, V12, +V13 +X01, Y01, +Z01 +Vector components of an axis about which tipping is performed. +X, Y and Z coordinates of a point through which the tipping axis +passes. +DSITA +Tipping angle in degree. +DX, DY, DZ +Translation distances along global X-axis, Y-axis and Z-axis. +*CONTROL_FORMING_TIPPING +1. Keyword *INCLUDE can be used to include the file to be tipped or translated. +2. Tipping angle DISTA1 is defined in degree. Signs of the tipping angles follow +the “right hand rule”. +3. An example of the keyword is included below, to tip a part +23.0 degrees, -31.0 +degrees, and +8.0 degrees about X-, Y-, and Z-axis, respectively and passing +through the origin; and to translate the part 12.0mm, -6.0mm and 91.0mm along +X, Y, and Z axis, respectively. +*INCLUDE +trimmedpart.dynain +*CONTROL_FORMING_TIPPING +$ PID/PSID ITYPE ISTRAIN ISTRSS NMOVE + 1 0 1 1 4 +$ ROT/TRAN V11 V12 V13 X01 y01 z01 DSITA1 + 1 1.000 0.000000 0.000 0.000 0.000 0.000 23.0 +$ ROT/TRAN V21 V22 V23 X21 y21 z21 DSITA2 + 1 0.000 1.000000 0.000 0.000 0.000 0.000 -31.0 +$ ROT/TRAN V31 V32 V33 X31 y31 z31 DSITA3 + 1 0.000000 0.000 1.000 0.000 0.000 0.000 8.0 +$ ROT/TRAN DX DY DZ +2 12.0 -6.0 91.0 +Revision Information: +This feature is available starting in LS-DYNA Revision 53448, with major updates from +Revision 80261. It is also available in LS-PrePost4.0 eZSetup for metal forming +application (http://ftp.lstc.com/anonymous/outgoing/lsprepost/4.0/metalforming/). +*CONTROL_FORMING_TOLERANC +Purpose: This keyword utilizes a smoothing algorithm to reduce the output noise of the +strain ratio β (minor strain/major strain) in calculating the Formability Index (F.I.), +which predicts sheet metal failure under nonlinear strain paths frequently occurred in +metal forming application. This keyword must be used together with the NLP option in +and for *MAT_036 and *MAT_037 only; and applies to shell elements only. This feature +is jointly developed with the Ford Motor Company. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable DT/CYCLE WEIGHT OUTPUT +Type +F +F +Default +none +none +I +0 + VARIABLE +DESCRIPTION +DT/CYCLE +Flag for output option (time interval or cycle number). +DT/CYCLE.LT.0: The absolute value is the time interval +between outputs. +DT/CYCLE.GT.0: Cycle numbers between outputs. +WEIGHT +Coefficient α in equation below. +OUTPUT +Output flag. When OUTPUT is set to 1, information such as +integration point, element ID, time, strain ratio β, major and +minor strains will be output to the “.o” file (a scratch file from +batch queue run). +Remarks: +The incremental change of in-plane major and minor strains are smoothed according to +the following formula: +∆𝜖1(𝑛−1) ∗ (1 − 𝛼) + 𝑑𝜖1(𝑛) ∗ 𝛼 +∆𝜖2(𝑛−1) ∗ (1 − 𝛼) + 𝑑𝜖2(𝑛) ∗ 𝛼 +where, 𝑑𝜖1(𝑛) and 𝑑𝜖2(𝑛) are incremental changes of 𝜖1 and 𝜖2 in the current time step n, +∆𝜖1(𝑛−1) and ∆𝜖2(𝑛−1) are incremental changes of 𝜖1 and 𝜖2 in the previous time step n- +1. The weighting coefficient 𝛼 regulates the smoothness of the incremental changes in +𝜖1 and 𝜖2. +Strain ratio 𝛽 results from smoothed incremental major and minor strains and stored in +history variable #2 along with additional information in “.o” +file if running in a batch queueing system, or directly dumped onto the screen if +running in an interactive window. +𝛽 = +∆𝜖2(𝑛−1) ∗ (1 − 𝛼) + 𝑑𝜖2(𝑛) ∗ 𝛼 +∆𝜖1(𝑛−1) ∗ (1 − 𝛼) + 𝑑𝜖1(𝑛) ∗ 𝛼 +The upper limit of 𝛽 is set at 1.0 while the lower limit is: +where 𝑟 ̅ is the anisotropic parameter: +− +𝑟 ̅ +1 + 𝑟 ̅ +𝑟 ̅ = +𝑟0 + 2𝑟45 + 𝑟90 +where 𝑟0, 𝑟45 and 𝑟90 are Lankford parameter in the rolling, diagonal and transverse +direction, respectively. +The keyword usage is shown in the following partial input deck, where *MAT_3- +PARAMETER_BARLAT_NLP is used. Note NEIPS is set at 3 for output of 3 history +variables that include formability index (F.I.), strain ratio 𝛽 and effective plastic strain 𝜀̅. +*KEYWORD +*INCLUDE_TRIM +sim_trimming.dynain +⋮ +*DATABASE_EXTENT_BINARY +$ NEIPH NEIPS MAXINT STRFLG SIGFLG EPSFLG RLTFLG ENGFLG + 3 &nip 1 +⋮ +*PARAMETER_EXPRESSION +R d3plot endtime/1000.0 +R nt -1.0*d3plot +... +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*CONTROL_FORMING_TOLERANC +$ DT/CYCLE WEIGHT OUTPUT + &nt 0.15 1 +*MAT_3-PARAMETER_BARLAT_NLP +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +$ MID RO E PR HR + 13 7.8E-09 2.07E+05 0.30 3.000 +$ M R00 R45 R90 LCID + 6.000 1.200 1.450 1.090 99 +$ AOPT C P VLCID NLP + 2.000 200 +$ A1 A2 A3 + 1.000 0.000 0.000 +$ V1 V2 V3 D1 D2 D3 + 0.000 1.000 0.000 +*DEFINE_CURVE + 200 +$FORM LIMIT DIAGRAM + -0.7000 0.8309 + -0.4500 0.6805 + -0.2500 0.5081 +0.0000 0.2479 + 0.2000 0.3487 + 0.4000 0.3845 +*DEFINE_CURVE + 99 + 0.000000000E+00 0.166100006E+03 + 0.579999993E-02 0.189110001E+03 + 0.124000004E-01 0.204789993E+03 + 0.190999992E-01 0.218520004E+03 + 0.255999994E-01 0.230580002E+03 + ⋮ ⋮ + 0.100000000E+01 0.512053406E+03 +... +*END +As shown in Figure 12-59, beta smoothed using smoothing algorithm is much better +than unsmoothed one. Most importantly, a plot of strain path (Figure 12-60) in the +traditional FLD space (𝜖1 vs. 𝜖2) confirms the terminal beta is approximately 0.9, which +is much closer to the smoothed beta value (Figure 12-59) at the end of the simulation. +Output +items +Columns +IP # +Element ID +Time +β +𝜖1 +𝜖2 +1st to 8th +9th to18th +19th to 29th 30th to 40th 41th to 51th 52th to 62th +Table 12-2. “.o” file output information and positions. Note only the mid-IP +information are output. +Revision Information: +Revision history information is listed below. Output information in “.o” file currently +applies to SMP and 1 CPU MPP only. +1)LS-DYNA Revision 84159: β smoothing is enabled for *MAT_036. +2)Revision 110928: β smoothing is enabled for *MAT_037. +1.2 +0.8 +0.4 +0.0 +-0.4 +0.0 +Unsmoothed beta +Smoothed beta +0.005 +0.010 +0.015 +0.020 +Time (seconds) +Figure 12-59. Effect of smoothing on strain ration β. +Terminal trendline +y=1.11x+0.0651, β=0.9 +0.14 +0.12 +0.10 +0.08 +0.06 +0.04 +0.02 +0.00 +0.00 +0.02 +0.04 +0.06 +0.08 +0.10 +0.12 +0.14 +Minor true strain +Figure 12-60. Strain path and terminal strain ratio β value. + +*CONTROL_FORMING_TRAVEL +Purpose: This keyword allows user to define tool travel for each phase in a stamping +process simulation. The entire simulation process can be divided into multiple phases +corresponding to the steps of an actual metal forming process. This keyword is to be +used for tools that are pre-positioned above the sheet blank (or below the blank) and +ready for forming. For tools that are pre-positioned at their home positions, *CON- +TROL_FORMING_TRAVEL should be used. This keyword is used together with +*CONTROL_FORMING_USER. +NOTE: This option has been deprecated in favor of *CON- +TROL_FORMING_AUTOPOSITION_PARAME- +TER). +Define Travel Cards. Repeat Card as many times as needed to define travels in +multiple phases. The next “*” card terminates the input. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID +VID +TRAVEL +TARGET +GAP +PHASE +FOLLOW +Type +I +I +F +I +F +I +I +Default +none +none +none +none +1.0t +none +none + VARIABLE +DESCRIPTION +PID +VID +TRAVEL +TARGET +GAP +Part ID of a stamping tool, as defined in *PART. +Vector ID defining the direction of travel for the tool defined by +the PID. +The distance in which the tool will be traveled to complete +forming in the direction specified by the VID. If TRAVEL is +defined, it is unnecessary to define TARGET. +Target tool PID, as defined in *PART. The tool (defined by PID) +will be traveled to where the TARGET tool is to complete +forming. +The minimum distance between the tool (PID) and TARGET tool +at the home position (forming complete). The GAP is by default +the sheet blank thickness “t”. +DESCRIPTION +Phase number, starting sequentially from 1. For example, phase 1 +is the binder closing, and phase 2 is the drawing operation. +Part ID of a stamping tool to be followed by the tool (PID). When +this variable is defined, the distance between the tool (PID) and +part ID defined by FOLLOW, will remain constant during the +phase. + VARIABLE +PHASE +FOLLOW +Remarks: +FOLLOW can be used to reduce total simulation time. For example, in a toggle draw, +the upper punch travels together with the upper binder during binder closing phase, +thus reducing the upper travel distance during the draw, shortening the overall +termination time. +An example is provided in manual pages under *CONTROL_FORMING_USER. +*CONTROL_FORMING_TRIM_MERGE +Purpose: This feature allows for automatic close of any open trim loop curve for a +successful trimming simulation. Previously, sheet metal trimming would fail if a trim +curve does not form a closed loop. This keyword is used together with *DEFINE_- +CURVE_TRIM, *ELEMENT_TRIM, *DEFINE_VECTOR, *CONTROL_ADAPTIVE_- +CURVE, *CONTROL_CHECK_SHELL, and applies to shell elements only. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IMERGE +GAPM +Type +Default +I +1 +F +0.0 + VARIABLE +DESCRIPTION +IMERGE +Activation flag. Set to ‘1’ (default) to activate this feature. +GAPM +Gap distance between two open ends of a trim loop curve in the +model. If the gap is smaller than GAPM, the two open ends of a +trim curve will be closed automatically. +Remarks: +1. +If multiple open trim loop curves exist, GAPM should be set to a value larger +than any of the gap distances of any trim curves in the trim model. +2. An example provided below shows that for both 3D (#90905) and 2D trim curve +(#90907), each with an open gap of 2.3 and 2.38mm, respectively. An automatic +merge operation is being performed with the GAPM set at 2.39 mm. Since this +set value is larger than both gaps in the model, trimming will automatically +close the gap for both curves and to form two closed-loop curves for a success- +ful trim. In Figure 12-61, two different 2D trimming results are illustrated with +GAPM of 2.39 (successful) as well as 2.37 (fail). +*KEYWORD +*INCLUDE_TRIM +drawn2.dynain +⋮ +*CONTROL_ADAPTIVE_CURVE +$ IDSET ITYPE N SMIN + &blksid 2 3 0.6 +GAP=2.38 mm +Trim vector +2D trim with GAPM=2.39 +Trim loop curve +GAP=2.38 mm +2D trim with GAPM=2.37 +Figure 12-61. A 2D trimming with different GAPM values. +*CONTROL_CHECK_SHELL +$ PSID IFAUTO CONVEX ADPT ARATIO ANGLE SMIN + &blksid1 1 1 1 0.250000150.000000 0.000000 +*DEFINE_CURVE_TRIM_3D +$# tcid tctype tflg tdir tctol toln nseed1 +nseed2 + 90907 2 1 0 1.250000 2.500000 0 +0 +sim_trimline_03.igs +*DEFINE_CURVE_TRIM_NEW +$# tcid tctype tflg tdir tctol toln nseed1 +nseed2 + 90905 2 0 2 1.250000 1.000000 0 +0 +$# filename +sim_trimline_02.igs +*DEFINE_VECTOR_TITLE +vector for Trim curve 90905 +$# vid xt yt zt xh yh zh +cid +2 0.000 0.000 0.000 -0.170000 0.950000 -0.260000 +0 +*ELEMENT_TRIM +&blksid +*DEFINE_TRIM_SEED_POINT_COORDINATES +$ NSEED,X1,Y1,Z1,X2,Y2,Z2 +1,&seedx,&seedy,&seedz +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+--- +-8 +*CONTROL_FORMING_TRIM_MERGE +$ IMERGE GAPM + 1 2.39 +$ Note that the 3D trim curve has a gap of 2.3 and the 2D trim curve has a gap +of 2.38 +*END +3. This feature is available starting in LS-DYNA Revision 84098. +*CONTROL_FORMING_TRIMMING +Purpose: Define a part subset to be trimmed by *DEFINE_CURVE_TRIM. This feature +is intended for metal forming simulation. Currently trimming is enabled on 2D and 3D +trimming of shell elements, 3D solid element, adaptive sandwiched parts (one layer of +solid elements with top and bottom layers of shell elements), non-adaptive sandwiched +parts (multiple layers of solid elements with top and bottom layers of shell elements), +and 2-D trimming of thick shell elements (TSHELL). Note it is not applicable to +axisymmetric solids or 2D plane strain/stress elements. For details, see *DEFINE_- +CURVE_TRIM. +NOTE: Before revision 87566 this card was called ELE- +MENT_TRIM. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PSID +ITYP +Type +I +Default +none +I +0 + VARIABLE +DESCRIPTION +Part set ID for trimming, see *SET_PART. +Activation flag for sandwiched parts (laminates) trimming: +ITYP.EQ.0: Trimming for solid elements. +ITYP.EQ.1: Trimming for laminates. +PSID +ITYP +Remarks: +This keyword is used together with *DEFINE_CURVE_TRIM to trim the parts defined +in PSID at time zero, i.e., before any stamping process simulation begins. Elements in +the part set will be automatically trimmed in the defined direction if they intersect the +trim curves. See examples in keyword section *DEFINE_CURVE_TRIM. +*CONTROL_FORMING_TRIMMING +1. Revision 87566: *ELEMENT_TRIM was changed to the current name *CON- +TROL_FORMING_TRIMING. +2. Revision 95745: *CONTROL_FORMING_TRIMING was changed to *CON- +TROL_FORMING_TRIMMING. +3. Revision 92088: 2-D trimming of solid elements is implemented. +4. Revision 92289: 2-D and 3-D trimming of laminates (ITYP) is added. +5. Revision 93467: 3-D trimming of solid elements is added. +6. Latter Revisions may incorporate more improvements and are suggested to be +used for trimming. +*CONTROL_FORMING_UNFLANGING_{OPTION} +Available options include: + +OUTPUT +Purpose: The keyword unfolds flanges of a deformable blank onto a rigid tooling mesh +using an implicit statics solver. This is typically used in trim line unfolding during a +stamping die development process. The option OUTPUT must be used together with +*CONTROL_FORMING_UNFLANGING to get the modified trim curves. Other +keywords related to blank size development are, *CONTROL_FORMING_ONESTEP, +and *INTERFACE_BLANKSIZE_DEVELOPMENT. +Card 1 for no option, : + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable NOPTION +DVID +NUNBEND STFBEND STFCNT +IFLIMIT +DIST +ILINEAR +Type +I +I +I +F +F +I +F +Default +none +N/A +none +none +none +none +none +I +2 +Card 2 for no option, : + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NB1 +NB2 +NB3 +CHARLEN NDOUTER +Type +I +I +I +F +I +Default +none +none +none +150.0 +none +*CONTROL_FORMING_UNFLANGING + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +THMX +THMN +EPSMX +Type +I +I +I +Default +1020 +0.0 +1020 + VARIABLE +DESCRIPTION +NOPTION +Flag to turn on an unfolding simulation: +EQ.1: Activate the unfolding simulation program. +DVID +This variable is currently not being used. +NUNBEND +Estimated number of unbending, ranging from 10 to 100. +STFBEND +Unflanging stiffness, ranging from 0.1 to 10.0. +STFCNT +Normal stiffness, ranging from 0.1 to 10.0. +IFLIMIT +DIST +Iteration limit for the first phase of unfolding, typically ranging +from 11 to 400. +Distance tolerance for auto-SPC along flange root. DIST (Figure +12-63) is usually slightly more than ½ of the flange thickness. This +field must be left blank for ILINEAR = 2. Also, nodes along the root +can be directly positioned on the rigid body surface (addendum), +leaving a DIST of zero (Figure 12-63). +ILINEAR +Unfolding algorithm selection flag: +EQ.0: Nonlinear unfolding. +EQ.1: Linear unfolding. +EQ.2: A hybrid unfolding method (Revision 87100 and later). +The curved 3D meshes of the flange will first be mapped +onto the tooling surface to be used as a starting porting +for nonlinear iterations; unfolding completes when force +balance is reached. (recommended). +VARIABLE +NB1 +NB2 +NB3 +CHARLEN +NDOUTER +THMX +DESCRIPTION +The start node ID (Figure 12-64) on a flange root boundary (fixed +end of the flange, see Figures 12-63 and 12-64). For closed-loop +flange root boundary, only this parameter needs to be defined; for +open-loop flange root boundary, define this parameter as well as +NB2 and NB3. The solver will automatically identify and +automatically impose the necessary boundary constraints on all +the nodes along the entire three-dimensional flange root +boundary. +The ID of a node in the middle of the flange root boundary, see +Figure 12-64. Define this parameter for open-loop flange root +boundary only. +The end node ID on a flange root boundary. Define this +parameter for open-loop flange root boundary only. The “path” +formed by NB1, NB2 and NB3 can be in any direction, meaning +NB1 and NB3 (Figure 12-64) can be interchangeable. +Maximum flange height (Figure 12-64) to limit the search region +for the boundary nodes along the flange root. This value should +be set bigger than the longest width (height) of the flange; and it +is needed in some cases. This parameter is now automatically +calculated as of Revision 92860. +A node ID on the outer flange (free end of the flange) boundary. +This node helps search of nodes along the flange root, especially +when holes are present in the flange area, see Figure 12-64. +Maximum thickness beyond which elements are deleted; this is +useful in removing wrinkling areas of the flange (shrink flange). +Modified, unfolded flange outlines based on this parameter are +stored in a file called “trimcurve_upd.k”, written using the *DE- +FINE_CURVE_TRIM_3D; keyword. The modified flanges (before +unfolding) are in a keyword file called “mdfiedflangedpart.k”; and +the unmodified flange (unfolded) is in “trimcurve_nmd.k”, also +written using keyword *DEFINE_CURVE_TRIM_3D. See the +example in Figure 12-64 for an explanation. Currently the +modified flange and curves are not smooth, which will be +improved in the future. To convert between *DEFINE_CURVE_- +TRIM_3D and IGES format, refer to Figures in *INTERFACE_- +BLANKSIZE. +THMN +*CONTROL_FORMING_UNFLANGING +DESCRIPTION +Minimum thickness below which elements are deleted; this is +useful in removing overly thinned areas of the flange (stretch +flange). Updated flange information based on this parameter is +stored in files listed above. +EPSMX +Maximum effective plastic strain beyond which elements are +deleted; this is useful in removing flange areas with high effective +plastic strains (stretch flange). Updated flange information based +on this parameter is stored in files listed above. +Introduction: +Unfolding of flanges is one of the first steps in a stamping die development process. +Immediately after tipping, binder and addendums are built for unfolding of flanges. +According to process considerations (trim conditions, draw depth, and material +utilization, etc.), the addendums are built either in parallel or perpendicular to the draw +die axis, tangentially off the main surface off the breakline , or any +combinations of the three scenarios. Trim lines are developed by unfolding the flanges +in finished (hemmed or flanged) position onto these addendums. Addendum length in +some areas may have to be adjusted to accommodate the unfolded trim lines. Trim line +development is very critical in hard tool development. Inaccurate trim lines lead to +trim die rework, result in many hours of re-welding, re-machining and re-spotting of +trim die components. +Input and output: +The inputs for the keyword are: +1. blank or flanges in the finished configuration, and, +2. +the draw die surface in mesh. +Meshes for flanges should of a quality similar to the blank mesh one would build for a +forming simulation. In LS-PrePost 4.0, this kind of mesh can be created using Mesh → +Automesh → Size. Element formulation 16 with NIP set to 5 is recommended for the +blank. The output results, in terms of unfolding steps and final unfolded flanges, are +stored in the d3plot files. LS-PrePost 4.0 function of Curve → Spline → From Mesh → By +part can be used to create unfolded flange/trim curves from the unfolded flanges. Since +the program uses an implicit statics solver, the double precision version of LS-DYNA +must be used. +Other modeling guidelines: +1. All addendum and flanges need to be oriented as if they are in a draw position, +with the drawing axis parallel to the global Z-axis; specifically the flanges need +to be on top of the addendum, as noted in Figures 12-62, 12-63 and 12-64. +2. Normals of the to-be-unfolded flange side and tool surface side must be +consistent and must face against each other when the flange is unfolded, see +Figure 12-64. +3. Holes in the blank are allowed only for ILINEAR = 2. +4. Adaptive re-meshing is not supported. +5. To-be-unfolded flange and tool meshes must not share the same nodes. This +can be easily done using the mesh detaching feature under EleTol → DetEle in +LS-PrePost. +6. Meshes of the flange part and rigid tool can slightly overlap each other, but +large amounts of overlap (area of flange already on addendum surface) is not +allowed. In LS-PrePost the EleTol → PtTrim feature can trim off the overlapped +flange portion. The curves used for the trimming can be obtained from the +flange tangent curves on the addendum (which has a more regulated mesh +pattern) using LS-PrePost’s Curve → Spline → Method From Mesh → By Edge +→ Prop feature with appropriate angle definition. Furthermore, any holes are +not allowed in the overlapping area. +7. +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE +should be +used for the contact between the blank and tool. Negative tool offsets on the +*CONTACT_… keyword is not supported. +8. The rigid tool (total fixed in *MAT_020) must be larger than the unfolded +flanges, especially along symmetric lines. This may be obvious, nevertheless it +is sometimes overlooked. +9. Nodes along the flange root are automatically fixed by defining NB1, NB2 and +NB3, as shown in Figure 12-64. +10. No “zigzag” along the flange root boundary, meaning that the boundary along +the flange root must be smooth. This restriction is removed as of Revision +92727. +11. Symmetric boundary conditions are supported. +12. Thickness and effective plastic strain are stored in a file “unflanginfo.out”, +which can be plotted in LS-PrePost 4.0, see Figure 12-64. +*CONTROL_FORMING_UNFLANGING +A partial input deck is provided below for flange unfolding of a fender outer, modified +from the original NCAC Taurus model. Shown in Figure 12-62 are the progressions of +the unfolding process, where the finished flanges are to be unfolded onto the +addendum (rigid body). A section view of the same unfolding before and after is found +in Figure 12-63. ILINEAR is set at 2 while DIST is left blank. Total numbers of elements +are 1251 on the blank and 6600 on the tooling. It took less than 3 minutes on an 8 CPU +(SMP) machine. Note that additional keywords, such as *CONTROL_IMPLICIT_- +FORMING, etc. are used. Termination criterion is set using the variable DELTAU in +*CONTROL_IMPLICIT_TERMINATION. Termination is reached when the relative +displacement ratio criterion is met, as indicated in the messag file. Termination time of +10.0 (steps) is sufficient for most cases, but may need to be extended in some cases to +satisfy the DELTAU in some cases. +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*KEYWORD +*INCLUDE +toolblankmesh.k +*CONTROL_FORMING_UNFLANGING +$ NOPTION DVID NUNBEND STFBEND STFCNT IFLIMIT DIST ILINEAR + 1 100 0.2 15.0 400 2 +$ NB1 NB2 NB3 CHARLEN NDOUTER + 321 451 322 60.0 6245 +*CONTROL_IMPLICIT_FORMING +1 +*CONTROL_IMPLICIT_TERMINATION +$ DELTAU +$ set between 0.0005~0.001 + 0.0005 +*CONTROL_IMPLICIT_GENERAL +$ IMFLAG DT0 + 1 .1000 +*CONTROL_IMPLICIT_SOLUTION +$ NSLOLVR ILIMIT MAXREF DCTOL ECTOL RCTOL LSTOL + 2 2 1100 0.100 1.e20 1.e20 +$ dnorm divflag inistif + 0 2 0 1 1 +*PARAMETER +R ENDTIME 10.0 +I elform 16 +I nip 5 +R bthick 1.0 +*PARAMETER_EXPRESSION +R D3PLOTS ENDTIME/60.0 +*CONTROL_TERMINATION +&ENDTIME +*DATABASE_BINARY_D3PLOT +&D3PLOTS +*CONTROL_RIGID... +*CONTROL_HOURGLASS... +*CONTROL_BULK_VISCOSITY... +*CONTROL_SHELL... +*CONTROL_CONTACT +$ SLSFAC RWPNAL ISLCHK SHLTHK PENOPT THKCHG ORIEN + 0.01 0.0 2 1 4 0 4 +$ USRSTR USRFAC NSBCS INTERM XPENE SSTHK ECDT TIEDPRJ + 0 0 10 0 2.0 0 +*CONTROL_ENERGY... +*CONTROL_ACCURACY... +*DATABASE_EXTENT_BINARY... +*SECTION_SHELL_TITLE +BLANK/FLANGE thickness and elform/nip specs. +&blksec &elform 0.833 &nip 1.0 +&bthick,&bthick,&bthick,&bthick +*PART... +*MAT_TRANSVERSELY_ANISOTROPIC_ELASTIC_PLASTIC... +*MAT_RIGID... +*CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE +$ SSID MSID SSTYP MSTYP SBOXID MBOXID SPR MPR + &blkpid &diepid 3 3 +$ FS FD DC VC VDC PENCHK BT DT + 0.125 0.0 0.0 0.0 20.0 0 0.0 1.000E+20 +$ SFS SFM SST MST SFST SFMT FSF VSF + 1.0 1.0 0.0 +$ SOFT SOFSCL LCIDAB MAXPAR PENTOL DEPTH BSORT FRCFRQ + 0 +$ PENMAX THKOPT SHLTHK SNLOG ISYM I2D3D SLDTHK SLDSTF +$ IGAP IGNORE DPRFAC DTSTIF FLANGL + 2 +*END +In Figure 12-64 (top), with THMN set at 0.4mm, the stretch flange area of the corner, +which has thickness less than 0.4mm, is removed; and the modified flange outlines are +created accordingly (bottom). The partial input used is listed below. +*CONTROL_FORMING_UNFLANGING +$ NOPTION DVID NUNBEND STFBEND STFCNT IFLIMIT DIST ILINEAR + 1 100 0.2 15.0 400 2 +$ NB1 NB2 NB3 CHARLEN NDOUTER + 321 451 322 60.0 6245 +*CONTROL_FORMING_UNFLANGING +$ THMX THMN EPSMX + 0.4 +Revision information: +The feature is available in double precision SMP, and starting in LS-DYNA Revision +73190. Revision information is listed below for various parameters and features: +1. +ILINEAR = 2: Revision 87100. +2. NDOUTER: Revision 87318. +3. CHARLEN: Revision 87210. +4. NB1, NB2, NB3: Revision 87100. +5. Option OUTPUT: Revision 86943. +6. Holes allowed: Revision 87167. +7. File “mdfiedflangedpart”: Revision 87105. +8. Symmetric boundary condition: Revision 88359. +9. CHARLEN automatically calculated: Revision 92860. +10. “Zigzag” flange root boundary allowed: Revision 92727. +Finished flanges +30% +unfolded +Flanges must be on top of the +addendum in the draw position +Addendum +60% +unfolded +Unfolded flanges +100% +unfolded + Figure 12-62. Flange unfolding progression of a fender outer (original model +courtesy of NCAC at George Washington University). +Addendum +Finished (incoming) +flanges +Unfolded flanges +Flange root (fixed end) +Free end of the flange +Flanges must be on top of the +addendum in the draw position +DIST + Figure 12-63. A section view showing flange unfolding before and after. +Thickness contour +min=0.2257 +max=0.8533 +Thickness (mm) +Holes are allowed +Thickness in the +dark blue area less +than 0.4mm, at +which THMN is set. +Flange normals +Addendum normals +0.85 +0.79 +0.73 +0.67 +0.60 +0.54 +0.48 +0.41 +0.35 +0.29 + 0.23 +Addendum surface +Flange before unfolding +Unfolded flange. Thickness and +effective plastic strain contour are +stored in a file "unflanginfo.out" +NB3 +Flange must be on top of the +addendum in the draw position +CHARLEN +NDOUTER +NB2 +Flange root +boundary (fixed) +NB1 - define this only for a closed-loop +boundary; define all three (NB1, NB2, +NB3) for an open-loop boundary. +Original flange is modified based on +THMN=0.4 and the mesh is stored in a file +"mdfiedflangedpart.k". Boundary curves +can be created using LSPP4.0 under +Curve/Spline/From mesh/by part. +Modified boundary curves on +unfolded flange are stored in a file +"trimcurve_upd.k"; original boundary +curves (without the corner cutout) is +in "trimcurve_nmd.k". +Figure 12-64. Unfolding details and output files +*CONTROL_FORMING_USER +Purpose: This keyword, along with *CONTROL_FORMING_POSITION, or *CON- +TROL_FORMING_TRAVEL, allow user to set up a stamping process simulation. From +this card various model parameters may be specified: +• material properties, +• material model, +• tooling kinematics, +• mesh adaptivity +• D3PLOT generation +NOTE: This option has been deprecated in favor of *CON- +TROL_FORMING_AUTOPOSITION_PARAME- +TER). + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +BLANK +TYPE +THICK +R00 +R45 +R90 +AL/FE +UNIT +Type +I +Default +none + Card 2 +1 +Variable +LCSS +Type +I +I +0 +2 +K +F +F +F +F +F +none +1.0 +R00 +R00 +3 +N +F +4 +E +F +5 +6 +DENSITY +PR +F +F +A +F +7 +FS +F +I +1 +8 +MTYPE +I +Default +none +none +none +none +none +none +0.1 +37 +Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PATERN +VMAX +AMAX +LVLADA +SIZEADA ADATIMS +D3PLT +GAP +Type +Default +I +1 +F +F +1000.0 500000. +I +0 +F +0 +I +0 +I +F +10 +1.1t + VARIABLE +DESCRIPTION +BLANK +PID of a sheet blank, as in *PART. +TYPE +Flag of part or part set ID for the blank: +EQ.0: Part ID. +EQ.1: Part set ID. +THICK +R00, R45, +R90 +AL/FE +UNIT +LCSS +Thickness of the blank. This variable is ignored if the thickness is +already defined in *SECTION_SHELL. +Material anisotropic parameters. For transverse anisotropy the R +value is set to the average value of R00, R45, and R90. +This parameter is used to define the Young’s Modulus, E, and +density, ρ, for the sheet blank. If this variable is defined, E and ρ +will be found by using the proper unit, as listed in Table 8.1, +under *CONTROL_FORMING_TEMPLATE. +EQ.A: the blank is aluminum +EQ.F: the blank is steel (default) +Units adopted in this simulation. Define a number between 1 and +10. Table 8.1 is used to determine the value for UNIT. This unit is +used to obtain proper values for punch velocity, acceleration, +time step, and physical and material properties. +If the material for the blank has not been defined, this curve will +be used to define the stress-strain relation. Otherwise, this +variable is ignored. +PREBD +“Pull-over” distance for the upper and lower binders after closing +in a 4-piece stretch draw, as shown in Figure 12-57. +VARIABLE +DESCRIPTION +K +N +E +Strength coefficient for exponential hardening (𝜎̅̅̅̅̅ = 𝑘𝜀̅ 𝑛). If LCSS +is defined, or if a blank material is defined with *MAT_036 or +*MAT_037, this variable is ignored. +Exponent for exponential hardening (𝜎̅̅̅̅̅ = 𝑘𝜀̅ 𝑛). If LCSS is +defined, or if a blank material is defined with *MAT_036 or +*MAT_037, this variable is ignored. +Young’s Modulus. If AL/FE is user defined, E is unnecessary. +DENSITY +Material density of the blank. If AL/FE is defined, this variable is +unnecessary. +PR +FS +MTYP +Poisson’s ratio. If AL/FE is user defined, this variable is +unnecessary. +Coulomb friction coefficient. If contact is defined with *CON- +TACT_FORMING_..., this variable is ignored. +Material model identification number, for example, 36 for +*MAT_036 and 37 for *MAT_037. Currently only material models +36 and 37 are supported. +PATERN +Velocity profile of the moving tool. If the velocity and the profile +are defined by *BOUNDARY_PRESCRIBED_MOTION_RIGID, +and *DEFINE_CURVE, this variable is ignored. +EQ.1: Ramped velocity profile. +EQ.2: Smooth velocity curve. +VMAX +The maximum allowable tool travel velocity. +AMAX +The maximum allowable tool acceleration. +LVLADA +Maximum mesh adaptive level. +SIZEADA +Minimum element size permitted during mesh adaptivity. +ADATIMS +Total number of adaptive steps during the simulation. +D3PLT +The total number of output states in the D3PLOT database. +GAP +Minimum gap between two closing tools at home position, in the +travel direction of the moving tool. This variable will be used for +*CONTROL_FORMING_POSITION. +Keyword examples: +A partial keyword example provided below is for tools in their home positions in a +simple 2-piece crash forming die. A steel sheet blank PID 1, is assigned with a thickness +of 0.76mm (UNIT = 1) and *MAT_037 with anisotropic values indicated, to follow +hardening curve of 90903, form in a ‘ramped’ type of velocity profile with maximum +velocity of 5000mm/s and acceleration of 500000.0 mm/s2, adapt mesh 5 levels with +smallest adapted element size of 0.9 for a total of 20 adaptive steps, create a total of 15 +post-processing states, and to finish forming with a final gap of 1.1mm between the +tools (PID3 and 5) at home position. The upper tool with PID 3 is to be moved back in Z +axis to clear the interference with the blank before close toward the lower tool of target +PID 5. +*CONTROL_FORMING_USER +$ BLANK TYPE THICK R00 R45 R90 AL/FE UNIT + 1 0 0.76 1.5 1.6 1.4 F 1 +$ LCSS K N E DENSITY PR FS MTYPE + 90903 37 +$ PATTERN VMAX AMAX LVLADA SIZEADA ADATIMS D3PLT GAP + 1 5000.0 500000.0 5 0.9 20.0 15.0 1.1 +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*CONTROL_FORMING_POSITION +$ This is for tools in home position. +$ PID PREMOVE TARGET + 3 5 +The following partial keyword example is for tools already positioned in relationship to +the blank and ready to close. All assigned properties for the blank remain the same. +Here the upper tool PID3 is not going to be moved back, but instead it will move +forward to close with the lower tool of target PID 5 in the direction specified by the +vector ID 999. +*CONTROL_FORMING_USER + 1 0 1.0 1.5 1.6 1.4 F 1 + 90903 37 + 1 5000.0 500000.0 5 0.9 20.0 15.0 1.1 +*CONTROL_FORMING_TRAVEL +$ PID VID TRAVEL TARGET GAP PHASE FOLLOW + 3 999 5 1.1 1 +Revision information: +This keyword is available starting in LS-DYNA Revision 48319. +*CONTROL_FREQUENCY_DOMAIN +Purpose: Set global control flags and parameters for frequency domain analysis. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +REFGEO +MPN +Type +Default +I +0 +F +0.0 + VARIABLE +DESCRIPTION +REFGEO +Flag for reference geometry in acoustic eigenvalue analysis: +EQ.0: use original geometry (t = 0), +EQ.1: use deformed geometry at the end of transient analysis. +MPN +Large mass added per node, to be used in large mass method for +enforced motion. +Remarks: +1. For +acoustic +eigenvalue +keyword +*FREQUENCY_DOMAIN_ACOUSTIC_ FEM_EIGENVALUE), sometimes it is +desired to extract the eigenvalues at the end of transient analysis, based on the +deformed geometry. This is useful to study the effect of loading history on +acoustic eigenvalues. In this case, one can set REFGEO = 1 to use the deformed +geometry at the end of transient analysis. +analysis + in FRF, SSD, or random vibration analysis, one can use the large mass +method to compute the response. With the large mass method, the user attach- +es a large mass to the nodes under excitation. LS-DYNA converts the enforced +motion excitation to nodal force on the same nodes in the same direction, to +produce the desired enforced motion. MPN is the large mass attached to each +node under excitation (usually it is in the range of 105-107 times of the original +mass of the entire structure). User still need to apply the large mass to the +nodes using the keyword *ELEMENT_MASS_{OPTION}. +The large nodal force p is computed as follows, +For nodal acceleration, 𝑝 = 𝑚𝐿𝑢̈ +For nodal velocity, 𝑝 = 𝑖 𝜔𝑚𝐿𝑢̇ +For nodal displacement, 𝑝 = − 𝜔2𝑚𝐿𝑢 +where 𝜔 is the round frequency, 𝑚𝐿 is the large mass attached to each node +(MPN), 𝑢̈, 𝑢̇ and 𝑢 are the enforced acceleration, velocity and displacement. +*CONTROL_HOURGLASS_{OPTION} +Available options include: + +936 +The “936” option switches the hourglass formulation for shells so that it is identical to +that used in LS-DYNA version 936. The modification in the hourglass control from +version 936 was to ensure that all components of the hourglass force vector are +orthogonal to rigid body rotations. However, problems that run under version 936 +sometimes lead to different results in versions 940 and later. This difference in results is +primarily due to the modifications in the hourglass force vector. Versions released after +936 should be more accurate. +Purpose: Redefine the default values of hourglass control type and coefficient. +3 +4 +5 +6 +7 +8 + Card 1 +1 +Variable +IHQ +Type +I +Default +2 +QH +F +0.1 +Remarks +1,2 +3,4 + VARIABLE +DESCRIPTION +IHQ +Default hourglass control type: +EQ.0: see Remark 1, +EQ.1: standard viscous form (may inhibit body rotation if +solid element shapes are skewed), +EQ.2: viscous form, Flanagan-Belytschko integration for solid +elements, +EQ.3: viscous form, Flanagan-Belytschko with exact volume +integration for solid elements, +EQ.4: stiffness form of type 2 (Flanagan-Belytschko), +EQ.5: stiffness form of type 3 (Flanagan-Belytschko) for solid +VARIABLE +DESCRIPTION +elements, +EQ.6: Belytschko-Bindeman +[1993] assumed +strain +co- +rotational stiffness form for 2D and 3D solid elements, +EQ.7: Linear total strain form of type 6 hourglass control. +EQ.8: Activates full projection warping stiffness for shell +formulations 16 and -16, and is the default for these +shell formulations. A speed penalty of 25% is common +for this option. +EQ.9: Puso [2000] enhanced assumed strain stiffness form for +3D hexahedral elements, +EQ.10: Cosserat Point Element (CPE) developed by Jabareen +and Rubin [2008] for 3D hexahedral elements and Jab- +areen et.al [2013] for 10-noded tetrahedral elements. See +Remark 6. +QH +Default hourglass coefficient. +Remarks: +1. Hourglass control is viscosity or stiffness that is added to quadrilateral shell +elements and hexahedral solid elements that use reduced integration. It also +applies to type 1 tshells. Without hourglass control, these elements would have +zero energy deformation modes which could grow large and destroy the solu- +tion. *CONTROL_HOURGLASS can be used to redefine the default values of +the hourglass control type and coefficient. If omitted or if IHQ = 0, the default +hourglass control types are as follows: +a) For shells: viscous type for explicit; stiffness type for implicit. +b) For solids: type 2 for explicit; type 6 for implicit. +c) For tshell formulation 1: type 2. +These default values are used unless HGID on *PART is used to point to +*HOURGLASS data which overrides the default values for that part. +For explicit analysis, shell elements can be used with viscous hourglass control, +(IHQ = 1 = 2 = 3) or stiffness hourglass control (IHQ = 4 = 5). Only shell forms +16 and -16 use the warping stiffness invoked by IHQ = 8. For implicit analysis, +the viscous form is unavailable. +For explicit analysis, hexahedral elements can be used with any of the hourglass +control types except IHQ = 8. For implicit analysis, only IHQ = 6, 7, 9, and 10 +are available. +If IHQ is set to a value that is invalid for some elements in a model, then the +hourglass control type for those elements is automatically reset to a valid value. +For explicit analysis, if IHQ = 6, 7, 9, or 10, then shell elements will be switched +to type 4 except for form 16 and -16 shells that are switched to type 8. If IHQ = +8, then solid elements and shell elements that are not form 16 or -16 will be +switched to type 4. For implicit analysis, if IHQ = 1-5, then solid elements will +be switched to type 6, and if IHQ = 1, 2, 3, 6, 7, 9, or 10, then shell elements will +switched to type 4. +2. Viscous hourglass control has been used successfully with shell elements when +the response with stiffness based hourglass control was overly stiff. As models +have grown more detailed and are better able to capture deformation modes, +there is less need for viscous forms. To maintain back compatibility, viscous +hourglass control remains the default for explicit analysis, but there may be +better choices, particularly the newer forms for bricks (6, 7, 9, and 10). +3. QH is a coefficient that scales the hourglass viscosity or stiffness. With IHQ = 1 +through 5 and IHQ = 8, values of QH that exceed 0.15 may cause instabilities. +Hourglass types 6, 7, 9, and 10 will remain stable with larger QH and can work +well with QH = 1.0 for many materials. However, for plasticity models, a +smaller value such as QH = 0.1 may work better since the hourglass stiffness is +based on elastic properties. +4. Hourglass types 6, 7, 9, and 10 for hexahedral elements are based on physical +stabilization using an enhanced assumed strain method. When element meshes +are not particularly skewed or distorted, their behavior may be very similar and +all can produce accurate coarse mesh bending results for elastic material with +QH = 1.0. However, form 9 gives more accurate results for distorted or skewed +elements. In addition, for materials 3, 18 and 24 there is the option to use a +negative value of QH. With this option, the hourglass stiffness is based on the +current material properties, i.e., the plastic tangent modulus, and scaled by +|QH|. +5. Hourglass type 7 is a variation on form 6. Instead of updating the hourglass +forces incrementally using the current stiffness and an increment of defor- +mations, the total hourglass deformation is evaluated each cycle. This ensures +that elements always spring back to their initial geometry if the load is removed +and the material has not undergone inelastic deformation. Hourglass type 7 is +recommended for foams that employ *INITIAL_FOAM_REFERENCE_GEOM- +ETRY. However the CPU time for type 7 is roughly double that for type 6, so it +is only recommended when needed. +6. Hourglass type 10 for 1-point solid elements or 10-noded tetrahedron of type 16 +are strucural elements based on Cosserat point theory that allows for accurate +representation of elementary deformation modes (stretching, bending and +torsion) for general element shapes and hyperelastic materials. To this end, the +theory in Jabareen and Rubin [2008] and Jabareen et.al [2013] has been general- +ized in the implementation to account for any material response. The defor- +mation is separated into a homogenous and an inhomogeneous part where the +former is treated by the constitutive law and the latter by a hyperelastic formu- +lation that is set up to match analytical results for the deformation modes men- +tioned above. Tests have shown that the element is giving more accurate +results than other hexahedral elements for small deformation problems and +more realistic behavior in general. +*CONTROL_IMPLICIT +Purpose: Set parameters for implicit calculation features. +*CONTROL_IMPLICIT_AUTO +*CONTROL_IMPLICIT_BUCKLE +*CONTROL_IMPLICIT_CONSISTENT_MASS +*CONTROL_IMPLICIT_DYNAMICS +*CONTROL_IMPLICIT_EIGENVALUE +*CONTROL_IMPLICIT_FORMING +*CONTROL_IMPLICIT_GENERAL +*CONTROL_IMPLICIT_INERTIA_RELIEF +*CONTROL_IMPLICIT_JOINTS +*CONTROL_IMPLICIT_MODAL_DYNAMIC +*CONTROL_IMPLICIT_MODAL_DYNAMIC_DAMPING_{OPTION} +*CONTROL_IMPLICIT_MODAL_DYNAMIC_MODE_{OPTION} +*CONTROL_IMPLICIT_MODES_{OPTION} +*CONTROL_IMPLICIT_ROTATIONAL_DYNAMICS +*CONTROL_IMPLICIT_SOLUTION +*CONTROL_IMPLICIT_SOLVER +*CONTROL_IMPLICIT_STABILIZATION +*CONTROL_IMPLICIT_STATIC_CONDENSATION +*CONTROL_IMPLICIT_TERMINATION +*CONTROL_IMPLICIT_AUTO_{OPTION} +Available options for OPTION include: + +DYN +SPR +Purpose: Define parameters for automatic time step control during implicit analysis +. The DYN option allows setting controls +specifically for the dynamic relaxation phase. The SPR option allows setting controls +specifically for the springback phase. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IAUTO +ITEOPT +ITEWIN +DTMIN +DTMAX +DTEXP +KFAIL +KCYCLE +Type +Default +I +0 +I +11 +I +5 +F +F +F +DT/1000. DT×10. +none + VARIABLE +DESCRIPTION +IAUTO +Automatic time step control flag +EQ.0: constant time step size +EQ.1: automatically adjust time step size +EQ.2: automatically adjust time step size and synchronize with +thermal mechanical time step. +LT.0: Curve ID = (-IAUTO) gives time step size as a function of +time. If specified, DTMIN and DTMAX will still be ap- +plied. +ITEOPT +ITEWIN +Optimum equilibrium iteration count per time step. See Figure +12-65. +Allowable iteration window. If iteration count is within ITEWIN +iterations of ITEOPT, step size will not be adjusted for the next +step. +ITEOPT ++ ITEWIN +ITEOPT +ITEOPT +- ITEWIN +No Auto-Adjust Zone +Figure 12-65. Iteration Window as defined by ITEOPT and ITEWIN. +Solution Time + VARIABLE +DTMIN +DESCRIPTION +Minimum allowable time step size. Simulation stops with error +termination if time step falls below DTMIN. +DTMAX +Maximum allowable time step size. +DTEXP +KFAIL +LT.0: curve ID = (-DTMAX) gives max step size as a function of +time. Also, the step size is adjusted automatically so that +the time value of each point in the curve is reached exact- +ly . +Time interval to run in explicit mode before returning to implicit +mode. Applies only when automatic implicit-explicit switching is +active (IMFLAG = 4 or 5 on *CONTROL_IMPLICIT_GENERAL). +Also, see KCYCLE. +EQ.0: defaults to the current implicit time step size. +LT.0: curve ID = (-DTEXP) gives the time interval as a function +of time. +Number of failed attempts to converge implicitly for the current +time step before automatically switching to explicit time +integration. + Applies only when automatic implicit-explicit +switching is active. The default is one attempt. If IAUTO = 0, any +input value is reset to unity. +DT0 +DTMAX > 0 +DTMAX > 0 +time step value +DTMIN +DTMIN +Time +Figure 12-66. The implicit time step size changes continuously as a function +of convergence within the bounds set by DTMIN and DTMAX + VARIABLE +KCYCLE +Remarks: + VARIABLE +IAUTO +ITEOPT +DESCRIPTION +Number of explicit cycles to run in explicit mode before returning +to the implicit mode. The actual time interval that is used will be +the maximum between DTEXP and KCYCLE*(latest estimate of +the explicit time step size). +REMARK +The default for IAUTO depends on the analysis type. For +“springback” analysis, automatic time step control and artificial +stabilization are activated by default. +With IAUTO = 1 or 2, the time step size is adjusted if convergence +is reached in a number of iterations that falls outside the specified +“iteration window”, increasing after “easy” steps, and decreasing + ITEOPT defines the +after “difficult” but successful steps. +midpoint of the iteration window. A value of ITEOPT = 30 or +more can be more efficient for highly nonlinear simulations by +allowing more iterations in each step, hence fewer total steps. +ITEWIN +The step size is not adjusted if the iteration count falls within +ITEWIN of ITEOPT. Large values of ITEWIN make the controller +more tolerant of variations in iteration count. +2.0 +1.0 +0.0 +-1.0 +DTMAX active from previous key point +to current key point +A key point is automatically +generated at the termination time +Problem Time +end +negative value ⇒ d3plot output +suppressed += Load curve points (DTMAX < 0), also key points += LS-DYNA generated key point +Figure 12-67. DTMAX < 0. The maximum time step is set by a load curve of +LCID = −DTMAX interpolated using piecewise constants. The abscissa values +of the load curve determine the set of key points. The absolute value of the +ordinate values set the maximum time step size. Key points are special time +values for which the integrator will adjust the time step so as to reach exactly. +For each key point with a positive function value, LS-DYNA will write the state +to the binary database. + VARIABLE +DTMAX +DTEXP +REMARK +To strike a particular simulation time exactly, create a key point +curve (Figure 12-67) and enter DTMAX = -(curve ID). This is +useful to guarantee that important simulation times, such as +when peak load values occur, are reached exactly. +When the automatic implicit-explicit switching option is activated +(IMFLAG = 4 or 5 on *CONTROL_IMPLICIT_GENERAL), the +solution method will begin as implicit, and if convergence of the +equilibrium iterations fails, automatically switch to explicit for a +time interval of DTEXP. A small value of DTEXP should be +chosen so that significant dynamic effects do not develop during +the explicit phase, since these can make recovery of nonlinear +equilibrium difficult during the next implicit time step. A +reasonable starting value of DTEXP may equal several hundred +VARIABLE +REMARK +explicit time steps. +*CONTROL_IMPLICIT_BUCKLE +Purpose: Activate implicit buckling analysis when termination time is reached . Optionally, buckling analyses are performed at +intermittent times. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NMODE BCKMTH +Type +I +I +Default +0 +see +below + VARIABLE +DESCRIPTION +NMODE +Number of buckling modes to compute +EQ.0: none (DEFAULT) +GT.0: compute n lowest buckling modes +LT.0: curve ID = (-NEIG) used for +intermittent buckling +analysis +BCKMTH +Method used to extract buckling modes +EQ.1: Use Block Shift and Invert Lanczos. Default of all +problems not using *CONTROL_IMPLICIT_INERTIA_- +RELIEF. +EQ.2: Use Power Method. Only valid option for problems +using *CONTROL_IMPLICIT_INERTIA_RELIEF. Op- +tional for other problems. See Remarks. +Remarks: +Buckling analysis is performed at the end of a static implicit simulation or at specified +times during the simulation. The simulation may be linear or nonlinear but must be +implicit. After loads have been applied to the model, the buckling eigenproblem is +solved: +[𝐊𝑀 + 𝜆𝐊𝐺]{𝑢} = 0 +where 𝐊𝑀 is the material tangent stiffness matrix, and the geometric or initial stress +stiffness matrix 𝐊𝐺 is a function of internal stress in the model. The lowest n +eigenvalues and eigenvectors are computed. The eigenvalues, written to text file +“eigout”, represent multipliers to the applied loads which give buckling loads. The +eigenvectors, written to binary database “d3eigv”, represent buckling mode shapes. +View and animate these modes using LS-PrePost. When NMODE > 0, eigenvalues will +be computed at the termination time and LS-DYNA will terminate. +When NMODE < 0, an intermittent buckling analysis will be performed. This is a +transient simulation during which loads are applied, with buckling modes computed +periodically during the simulation. Changes in geometry, stress, material, and contact +conditions will affect the buckling modes. The transient simulation must be implicit. +The curve ID = -NMODE indicates when to extract the buckling modes, and how many +to extract. Define one curve point at each desired extraction time, with a function value +equal to the number of buckling modes desired at that time. A d3plot database will be +produced for the transient solution results. Consecutively numbered d3eigv and eigout +databases will be produced for each intermittent extraction. The extraction time is +indicated in each database’s analysis title. +The buckling modes can be computed using either Block Shift and Invert Lanczos or the +Power Method. It is strongly recommended that the Block Shift and Invert Lanczos +method is used as it is a more powerful and robust algorithm. For problems using +*CONTROL_IMPLICIT_INERTIA_RELIEF the Power Method must be used and any +input value for BCKMTH will be overridden with the required value of 2. There may +be some problems, which are not using *CONTROL_IMPLICIT_INERTIA_RELIEF, +where the Power Method may be more efficient than Block Shift and Invert Lanczos. +But the Power Method is not as robust and reliable as Lanczos and results should be +verified. Furthermore convergence of the Power Method is better for buckling +problems where the expected buckling mode is close to one in magnitude and the +dominant mode is separated from the secondary modes. The number of modes +extracted via the Power Method should be kept in the range of 1 to 5. +The geometric stiffness terms needed for buckling analysis will be automatically +computed when the buckling analysis time is reached, regardless of the value of the +geometric stiffness flag IGS on *CONTROL_IMPLICIT_GENERAL. +A double precision executable should be used for best accuracy in buckling analysis. +Parameters CENTER, LFLAG, LFTEND, RFLAG, RHTEND and SHFSCL from *CON- +TROL_IMPLICIT_EIGENVALUE are applicable to buckling analysis. For buckling +analysis CENTER, LFTEND, RHTEND and SHFSCL are in units of the eigenvalue +spectrum. +*CONTROL_IMPLICIT_CONSISTENT_MASS +Purpose: Use the consistent mass matrix in implicit dynamics and eigenvalue solutions. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IFLAG +Type +Default +I +0 + VARIABLE +DESCRIPTION +IFLAG +Consistent mass matrix flag +EQ.0: Use the standard lumped mass formulation (DEFAULT) +EQ.1: Use the consistent mass matrix. +Remarks: +The consistent mass matrix formulation is currently available for the three and four +node shell elements, solid elements types 1, 2, 10, 15, 16, and 18 , and beam types 1, 2, 3, 4, and 5 . All other element types +continue to use a lumped mass matrix. +*CONTROL_IMPLICIT_DYNAMICS_{OPTION} +Available options include: + +DYN +SPR +Purpose: Activate implicit dynamic analysis and define time integration constants . The DYN option allows setting controls +specifically for the dynamic relaxation phase. The SPR option allows setting control +specifically for the springback phase. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IMASS +GAMMA +BETA +TDYBIR +TDYDTH +TDYBUR +IRATE +ALPHA +Type +Default +I +0 +F +F +F +F +F +.50 +.25 +0.0 +1028 +1028 +I +0 +F +0 + VARIABLE +DESCRIPTION +IMASS +Implicit analysis type +LT.0: curve ID = (-SCALE) used to control amount of implicit + TDYBIR, +dynamic effects applied to the analysis. +TDYDTH and TDYBUR are ignored with this option. +EQ.0: static analysis +EQ.1: dynamic analysis using Newmark time integration. +EQ.2: dynamic analysis by modal superposition following the +solution of the eigenvalue problem +EQ.3: dynamic analysis by modal superposition using the +eigenvalue solution in the d3eigv files that are in the +runtime directory. +GAMMA +Newmark time integration constant . +BETA +Newmark time integration constant . +100% +0% +TDYBIR +TDYDTH +TDYBUR +Time +Figure 12-68. Birth, death, and burial time for implicit dynamics. The terms +involving 𝑴 and 𝑫 are scaled by a factor between ranging between 1 and 0 to +include or exclude dynamical effects, respectively. + VARIABLE +DESCRIPTION +TDYBIR +Birth time for application of dynamic terms. See Figure 12-68. +TDYDTH +Death time for application of dynamic terms. +TDYBUR +Burial time for application of dynamic terms. +IRATE +Rate effects switch: +EQ.0: rate effects are on in constitutive models +EQ.1: rate effects are off in constitutive models +EQ.2: rate effects are off in constitutive models for both explicit +and implicit. +ALPHA +Composite time integration constant . +GT.0: Bathe composite scheme is activated +LT.0: HHT scheme is activated +Remarks: +For the dynamic problem, the linearized equilibrium equations may be written in the +form +𝑴𝒖̈𝑛+1 + 𝑫𝒖̇𝑛+1 + 𝑲𝑡(𝒙𝑛)Δ𝒖 = 𝑷(𝒙𝑛)𝑛+1 − 𝑭(𝒙𝑛) +where +𝑴 = lumped mass matrix +𝑫 = damping matrix +𝒖𝑛+1 = 𝒙𝑛+1 − 𝒙0 = nodal displacement vector +𝒖̇𝑛+1 = nodal point velocities at time 𝑛 + 1 +𝒖̈𝑛+1 = nodal point acceleration at time 𝑛 + 1 +Between the birth and death times 100% of the dynamic terms, that is the terms +involving M and D, are applied. Between the death and burial time the dynamic terms +are decreased linearly with respect to time until 0% of the dynamic terms are applied +after the burial time. This feature is useful for problems that are initially singular +because the parts are not in contact initially such as in metal stamping. For these +problems dynamics is required for stable convergence. When contact is established the +problem becomes well conditioned and the dynamic terms are no longer required for +stable convergence. It is recommend that for such problems the user set the death time +to be after contact is established and the burial time for 2 or 3 time steps after the death +time. +For problems with more extensive loading and unloading patterns the user can control +the amount of dynamic effects added to the model by using a load curve, see +IMASS.LT.0. This curve should have ordinate values between 0.0 and 1.0. The user +should use caution in ramping the load curve and the associated dynamic effects from +1.0 to 0.0. Such a ramping down should take place over 2 or 3 implicit time steps. +The time integration is by default the unconditionally stable, one-step, Newmark-β time +integration scheme +𝒖̈𝑛+1 = +Δ𝒖 +𝛽Δ𝑡2 − +𝒖̇𝑛 +𝛽Δ𝑡 +− +( +− 𝛽) 𝒖̈𝑛 +𝒖̇𝑛+1 = 𝒖̇𝑛 + Δ𝑡(1 − 𝛾)𝒖̈𝑛 + 𝛾Δ𝑡𝒖̈𝑛+1 +𝒙𝑛+1 = 𝒙𝑛 + Δ𝒖 +Here, Δ𝑡 is the time step size, and 𝛽 and 𝛾 are the free parameters of integration. For +𝛾 = 1 +4⁄ the method reduces to the trapezoidal rule and is energy +2⁄ and 𝛽 = 1 +conserving. If +γ > +𝛽 > ++ 𝛾) + , +( +Then numerical damping is induced into the solution leading to a loss of energy and +momentum. +The Newmark method, and the trapezoidal rule in particular, is known to lack the +robustness required for simulating long term dynamic implicit problems. Even though +numerical damping may improve the situation from this aspect, it is difficult to know +how to set 𝛾 and 𝛽 without deviating from desired physical properties of the system. In +the literature, a vast number of composite time integration algorithms have been +proposed to handle this, and a family of such methods is implemented and governed by +the value of 𝛼 (ALPHA, parameter 8 on card 1). For 𝛼 > 0, every other implicit time +step is a three point backward Euler step given as +𝒖̈𝑛+1 = +(1 + 𝛼) +∆𝑡 +(𝒖̇𝑛+1 − 𝒖̇𝑛) − +∆𝑡− +(𝒖̇𝑛 − 𝒖̇𝑛−1) +Δ𝒖 − +Δ𝒖− +𝒖̇𝑛+1 = +(1 + 𝛼) +∆𝑡 +∆𝑡− +where ∆𝑡− = 𝑡𝑛 − 𝑡𝑛−1 and Δ𝒖− = 𝒖𝑛 − 𝒖𝑛−1 are constants. Because of this three step +procedure, the method is particularly suitable for nodes/bodies undergoing curved +motion as it better accounts for curvature than the default Newmark step. For 𝛼 = 1/2, +and default values of 𝛾 and 𝛽, the method defaults to the Bathe time integration +scheme, Bathe [2007], and is reported to preserve energy and momentum to a +reasonable degree. The improvement in stability over the Newmark method is +primarily attributed to numerical dissipation, but fortunately this dissipation appears to +mainly be due to damping of high frequency content and the underlying physics is +therefore not affected as such, see Bathe and Nooh [2012]. +For a negative value of ALPHA, the HHT, Hilber-Hughes-Taylor [1977], scheme is +activated. This scheme is similar to that of the Newmark method, but the equilibrium is +sought at time step 𝑛 + 1 + 𝛼 instead of at 𝑛 + 1. As a complement to the Newmark +scheme above, we introduce +𝒖̇𝛼 = −𝛼𝒖̇𝑛 + (1 + 𝛼)𝒖̇𝑛+1 +𝒙𝛼 = −𝛼𝒙𝑛 + (1 + 𝛼)𝒙𝑛+1 +and solve a modified system of equilibrium equations +𝑴𝒖̈𝑛+1 + 𝑫𝒖̇𝛼 + 𝑭(𝒙𝛼) = 𝑷(𝒙𝛼). +3 ≤ 𝛼 ≤ 0 and 𝛾 = 1−2𝛼 +This method is stable for − 1 +, which becomes the +default values of 𝛾 and 𝛽 if not explicitly set. Parameter 𝛼 controls the amount of +dissipation in the problem, for 𝛼 = 0 an undamped Newmark scheme is obtained, +whereas 𝛼 = − 1 +3 introduces significant damping. From the literature, a value of +𝛼 = −0.05 appears to be a good choice. +2 and 𝛽 = (1−𝛼)2 +When modal superposition is invoked, NEIGV on *CONTROL_IMPLICIT_EIGENVAL- +UE indicates the number of modes to be used. With modal superposition, stresses are +computed only for linear shell formulation 18. +*CONTROL_IMPLICIT_EIGENVALUE +Purpose: Activate implicit eigenvalue analysis and define associated input parameters +. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NEIG +CENTER +LFLAG +LFTEND +RFLAG +RHTEND +EIGMTH +SHFSCL +Type +Default +I +0 +This card is optional. +F +I +F +I +F +I +F +0.0 +0 +-infinity +0 ++infinity +2 +0.0 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ISOLID +IBEAM +ISHELL +ITSHELL MSTRES EVDUMP MSTRSCL +Type +Default +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +F +0.001 + VARIABLE +NEIG +DESCRIPTION +Number of eigenvalues to extract. This must be specified. The +other parameters below are optional. +LT.0: curve ID = (-NEIG) used for intermittent eigenvalue +analysis +CENTER + This option +Center +eigenvalues located about this value. +frequency. +finds +the nearest NEIG +LFLAG +Left end point finite flag. +EQ.0: left end point is -infinity +EQ.1: left end point is LFTEND. +LFTEND +Left end point of interval. Only used when LFLAG = 1. +VARIABLE +DESCRIPTION +RFLAG +Right end point finite flag: +EQ.0: right end point is +infinity +EQ.1: right end point is RHTEND. +RHTEND +Right end point of interval. Only used when RFLAG = 1. +EIGMTH +Eigenvalue extraction method: +EQ.2: Block Shift and Invert Lanczos (default). +EQ.3: Lanczos with [M] = [I] (for debug only). +EQ.5: Same as 3 but include Dynamic Terms +SHFSCL +Shift scale. Generally not used, but see explanation below. +ISOLID +IBEAM +ISHELL +ITSHELL +If nonzero, reset all solid element formulations to ISOLID for the +implicit computations. Can be used for all implicit computations +not just eigenvalue computations. +If nonzero, reset all beam element formulations to IBEAM for the +implicit computations. Can be used for all implicit computations +not just eigenvalue computations. +If nonzero, reset all shell element formulations to ISHELL for the +implicit computations. Can be used for all implicit computations +not just eigenvalue computations. +If nonzero, reset all thick shell element formulations to ITSHELL +for the implicit computations. Can be used for all implicit +computations not just eigenvalue computations. +MSTRES +Flag for computing the stresses for the eigenmodes: +EQ.0: Do not compute the stresses. +EQ.1: Compute the stresses. +EVDUMP +*CONTROL_IMPLICIT_EIGENVALUE +DESCRIPTION +Flag for writing eigenvalues and eigenvectors to file “Eigen_ +Vectors” (SMP only): +EQ.0: Do not write eigenvalues and eigenvectors. +GT.0: Write eigenvalues and eigenvectors using an ASCII +format. +LT.0: Write eigenvalues and eigenvectors using a binary +format. +MSTRSCL +Scaling for computing the velocity based on the mode shape for +the stress computation. +Remarks: +To perform an eigenvalue analysis, activate the implicit method by selecting IM- +FLAG = 1 on *CONTROL_IMPLICIT_GENERAL, and indicate a nonzero value for +NEIG above. By default, the lowest NEIG eigenvalues will be found. If a nonzero +center frequency is specified, the NEIG eigenvalues nearest to CENTER will be found. +When NEIG > 0, eigenvalues will be computed at time = 0 and LS-DYNA will +terminate. +When NEIG < 0, an intermittent eigenvalue analysis will be performed. This is a +transient simulation during which loads are applied, with eigenvalues computed +periodically during the simulation. Changes in geometry, stress, material, and contact +conditions will affect the eigenvalues. The transient simulation can be either implicit or +explicit according to IMFLAG = 1 or IMFLAG = 6, respectively, on *CONTROL_IM- +PLICIT_GENERAL. The curve ID = -NEIG indicates when to extract eigenvalues, and +how many to extract. Define one curve point at each desired extraction time, with a +function value equal to the number of eigenvalues desired at that time. A d3plot +database will be produced for the transient solution results. Consecutively numbered +d3eigv and eigout databases will be produced for each intermittent extraction. The +extraction time is indicated in each database’s analysis title. +The Block Shift and Invert Lanczos code is from BCSLIB-EXT, Boeing's Extreme +Mathematical Library. +When using Block Shift and Invert Lanczos, the user can specify a semifinite or finite +interval region in which to compute eigenvalues. Setting LFLAG = 1 changes the left +end point from -infinity to the value specified by LFTEND. Setting RFLAG = 1 changes +the right end point from +infinity to the values given by RHTEND. If the interval +includes CENTER (default value of 0.0) then the problem is to compute the NEIG +eigenvalues nearest to CENTER. If the interval does not include CENTER, the problem +is to compute the smallest in magnitude NEIG eigenvalues. +If all of the eigenvalues are desired in an interval where both end points are finite just +input a large number for NEIG. The software will automatically compute the number +of eigenvalues in the interval and lower NEIG to that value. The most general problem +specification is to compute NEIG eigenvalues nearest CENTER in the interval +[LFTEND,RHTEND]. Computing the lowest NEIG eigenvalues is equivalent to +computing the NEIG eigenvalues nearest 0.0. +For some problems it is useful to override the internal heuristic for picking a starting +point for Lanczos shift strategy, that is the initial shift. In these rare cases, the user may +specify the initial shift via the parameter SHFSCL. SHFSCL should be in the range of +first few nonzero frequencies. +Parameters CENTER, LFTEND, RHTEND, and SHFSCL are in units of Hertz for +eigenvalue problems. These four parameters along with LFLAG and RFLAG are +applicable for buckling problems.. For buckling problems CENTER, LFTEND, +RHTEND, and SHFSCL are in units of the eigenvalue spectrum. +Eigenvectors are written to an auxiliary binary plot database named “d3eigv”, which is +automatically created. These can be viewed using a postprocessor in the same way as a +standard "d3plot" database. The time value associated with each eigenvector plot is the +corresponding frequency in units of cycles per unit time. A summary table of +eigenvalue results is printed to the "eigout" file. In addition to the eigenvalue results, +modal participation factors and modal effective mass tables are written to the “eigout” +file. The user can export individual eigenvectors using LSPrePost. +The user can request stresses to be computed and written to d3eigv via MSTRES. A +velocity is computed by dividing the displacements from the eigenmode by MSTRSCL. +The element routine then computes the stresses based on this velocity, but then those +stresses are inversely scaled by MSTRSCL before being written to d3eigv. Thus +MSTRSCL has no effect on results of linear element formulations. The strains +associated with the stresses output using the MSTRES option can be obtained by setting +the STRFLG on *DATABASE_EXTENT_BINARY. +Eigenvalues and eigenvectors can be written to file “Eigen_Vectors” by using a nonzero +value for EVDUMP. If EVDUMP > 0 an ASCII file is used. If EVDUMP < 0 a simple +binary format is used. The binary format is to reduce file space. The eigenvectors +written to this file will be orthonormal with respect to the mass matrix. Eigenvector +dumping is an SMP only feature. +The print control parameter, LPRINT, and ordering method parameter, ORDER, from +the *CONTROL_IMPLICIT_SOLVER keyword card also apply to the Block Shift and +Invert Eigensolver. +*CONTROL_IMPLICIT_FORMING_{OPTION} +Available options include: + +DYN +SPR +Purpose: This keyword is used to perform implicit static analysis, especially for metal +forming processes, such as gravity loading, binder closing, flanging, and stamping +subassembly simulation. A systematic study had been conducted to identify the key +factors affecting implicit convergence, and the preferred values are automatically set +with this keyword. In addition to forming application, this keyword can also be used in +other applications, such as dummy loading and roof crush, etc. The DYN option allows +setting controls specifically for the dynamic relaxation phase. The SPR option allows +setting controls specifically for the springback phase. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IOPTION +NSMIN +NSMAX +BIRTH +DEATH +PENCHK +Type +Default +I +1 +I +none +I +2 +F +F +F +0.0 +1.e+20 +0.0 + VARIABLE +DESCRIPTION +IOPTION +Solution type: +EQ.1: Gravity loading simulation, see remarks below. +EQ.2: Binder closing and flanging simulation, see remarks +below. +NSMIN +Minimum number of implicit steps for IOPTION = 2. +NSMAX +Maximum number of implicit steps for IOPTION = 2. +BIRTH +Birth time to activate this feature. +DEATH +Death time. +DESCRIPTION +Relative allowed penetration with respect to the part thickness in +contact for IOPTION = 2. +time +Initial +in +*CONTROL_IMPLICIT_GENERAL, which is no longer needed if +DT0 is specified here. +defined +size, +step +as + VARIABLE +PENCHK +DT0 +General remarks: +This keyword provides a simplified interface for implicit static analysis. If no other +implicit cards are used, the stiffness matrix is reformed every iteration. Convergence +tolerances (DCTOL, ECTOL, etc.) are automatically set and recommended no to be +changed. In almost all cases, only two additional implicit control cards (*CONTROL_- +IMPLICIT_GENERAL, and_AUTO) may be needed to control the stepping size, where +variables DT0, DTMIN and DTMAX can be used for control. +If multiple steps are required for IOPTION = 1, *CONTROL_IMPLICIT_GENERAL +must be placed after *CONTROL_IMPLICIT_FORMING with DT0 specified as a certain +fraction of the ENDTIM . Otherwise, even with DT0 +specified as a fraction of the ENDTIM, only one step (with step size of ENDTIM) will be +performed. +As always, the variable IGAP should be set to “2” in *CONTACT_FORMING… cards +for a more realistic contact simulation in forming. The contact type *CONTACT_- +FORMING_SURFACE_TO_SURFACE is recommended to be used with implicit +analysis. +Smaller penalty stiffness scale factor SLSFAC produces a certain amount of contact +penetration but yields faster simulation time, and therefore is recommended for gravity +and closing (in case of no physical beads) simulation. Subsequent forming process is +likely to follow and contact conditions will be reestablished there, where a tighter, +default SLSFAC (0.1) should be used. +It is recommended that the fully integrated element type 16 is to be used for all implicit +calculation. For solids, type “-2” is recommended. +Executable with double precision is to be used for all implicit calculation. +Models with over 100,000 deformable elements are more efficient to be simulated with +MPP for faster turnaround time. +*CONTROL_IMPLICIT_FORMING +An example of the implicit gravity is provided below, where a blank is loaded with +gravity into a toggle die. A total of five steps are used, controlled by the variable DT0. +The results are shown in Figure 12-69. If this binder closing is done with explicit +dynamics, efforts need to be made to reduce the inertia effects on the blank since contact +with the upper binder only happens along the periphery and a large middle portion of +the blank is not driven or supported by anything. With implicit static method, there is +no inertia effect at all on the blank during the closing, and no tool speed, time step size, +etc. to be concerned about. +The implicit gravity application for both air and toggle draw process is available +through LS-PrePost 4.0 in Metal Forming Application/eZ Setup (http://ftp.lstc.com/- +anonymous/outgoing/lsprepost/4.0/metalforming/). +*KEYWORD +*PARAMETER +⋮ +*CONTROL_TERMINATION +1.0 +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*CONTROL_IMPLICIT_FORMING +$ IOPTION + 1 +*CONTROL_IMPLICIT_GENERAL +$ IMFLAG DT0 + 1 0.2 +*CONTROL_CONTACT +$ SLSFAC RWPNAL ISLCHK SHLTHK PENOPT THKCHG ORIEN + 0.03 0.0 2 1 4 0 4 +$ USRSTR USRFAC NSBCS INTERM XPENE SSTHK ECDT TIEDPRJ + 0 0 10 0 1.0 0 +*PART + Blank + &blkpid &blksec &blkmid +*SECTION_SHELL +$ SID ELFORM SHRF NIP PROPT QR/IRID ICOMP SETYP +&blksec 16 0.833 7 1.0 +$ T1 T2 T3 T4 NLOC +&bthick,&bthick,&bthick,&bthick +*CONTACT_FORMING_SURFACE_TO_SURFACE +$ SSID MSID SSTYP MSTYP SBOXID MBOXID SPR MPR + &blksid &lpunsid 2 2 1 1 +$ FS FD DC VC VDC PENCHK BT DT + 0.12 0.0 0.0 0.0 20.0 0 0.0 1E+20 +$ SFS SFM SST MST SFST SFMT FSF VSF + 1.0 1.0 0.0 &mstp +$ SOFT SOFSCL LCIDAB MAXPAR PENTOL DEPTH BSORT FRCFRQ + 0 +$ PENMAX THKOPT SHLTHK SNLOG ISYM I2D3D SLDTHK SLDSTF + 1 +$ IGAP IGNORE DPRFAC DTSTIF FLANGL + 2 +⋮ +*LOAD_BODY_Z +90994 +*DEFINE_CURVE_TITLE +Body Force on blank +90994 +0.0,9810.0 +10.0,9810.0 +*LOAD_BODY_PARTS +&blksid +*END +Binder closing example: +An example of binder closing and its progression is shown in Figures 12-70, 12-71, +12-72, and 12-73, using the NUMISHEET’05 deck lid inner, where a blank is being +closed in a toggle die (modified). An adaptive level of three was used in the closing +process. Gravity is and should be always applied at the same time, regardless if a prior +gravity loading simulation is performed or not, as listed at the end of the input deck. +The presence of the gravity helps the blank establish an initial contact with the tool, +thus improving the convergence rate. The upper binder is moved down by a closing +distance (defined by a parameter &bindmv) using a displacement boundary condition +(VAD = 2), with a simple linearly increased triangle-shaped load curve. The variable +DT0 is set at 0.01, determined by the expected total deformation. The solver will +automatically adjust based on the initial contact condition. The maximum step size is +controlled by the variable DTMAX, and this value needs to be sufficiently small (<0.02) +to avoid missing contact, but yet not too small causing a long running time. In some +cases, this variable can be set larger, but the current value works for most cases. +*KEYWORD +*PARAMETER +⋮ +*CONTROL_TERMINATION +1.0 +*CONTROL_IMPLICIT_FORMING +$ IOPTION NSMIN NSMAX + 2 2 100 +*CONTROL_IMPLICIT_GENERAL +$ IMFLAG DT0 + 1 0.01 +*CONTROL_IMPLICIT_AUTO +$ IAUTO ITEOPT ITEWIN DTMIN DTMAX + 0 0 0 0.01 0.03 +*CONTROL_ADAPTIVE +⋮ +*CONTROL_CONTACT +$ SLSFAC RWPNAL ISLCHK SHLTHK PENOPT THKCHG ORIEN + 0.03 0.0 2 1 4 0 4 +$ USRSTR USRFAC NSBCS INTERM XPENE SSTHK ECDT TIEDPRJ + 0 0 10 0 1.0 0 +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +⋮ +*PART + Blank +$ PID SECID MID EOSID HGID GRAV ADPOPT TMID + &blkpid &blksec &blkmid &adpyes +*SECTION_SHELL +$ SID ELFORM SHRF NIP PROPT QR/IRID ICOMP SETYP +&blksec 16 0.833 7 1.0 +$ T1 T2 T3 T4 NLOC +&bthick,&bthick,&bthick,&bthick +⋮ +*CONTACT_FORMING_SURFACE_TO_SURFACE +$ SSID MSID SSTYP MSTYP SBOXID MBOXID SPR MPR + &blksid &lpunsid 2 2 1 1 +$ FS FD DC VC VDC PENCHK BT DT + 0.12 0.0 0.0 0.0 20.0 0 0.0 1E+20 +$ SFS SFM SST MST SFST SFMT FSF VSF + 1.0 1.0 0.0 &mstp +$ SOFT SOFSCL LCIDAB MAXPAR PENTOL DEPTH BSORT FRCFRQ + 0 +$ PENMAX THKOPT SHLTHK SNLOG ISYM I2D3D SLDTHK SLDSTF + 1 +$ IGAP IGNORE DPRFAC DTSTIF FLANGL + 2 +*CONTACT_... +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +*BOUNDARY_PRESCRIBED_MOTION_RIGID +$ typeID DOF VAD LCID SF VID DEATH BIRTH +&bindpid 3 2 3 -1.0 0 +*DEFINE_CURVE +3 +0.0,0.0 +1.0,&bindmv +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 +$ Activate gravity on blank: +*LOAD_BODY_Z +90994 +*DEFINE_CURVE_TITLE +Body Force on blank +90994 +0.0,9810.0 +10.0,9810.0 +*LOAD_BODY_PARTS +&blksid +*END +Binder closing with real beads example: +Binder closing with real beads can also be done with implicit static, and with adaptive +mesh. An example is shown in Figure 12-74, where a hood outer is being closed +implicitly. It is noted a small buckle can be seen near the draw bead region along the +fender line. These kind of small forming effects can be more accurately detected with +implicit static method. +The implicit static closing can now be set up in LS-PrePost v4.0 Metal Forming +Application/eZ Setup (http://ftp.lstc.com/anonymous/outgoing/lsprepost/4.0/metal- +forming/). +Flanging example: +An example of flanging simulation using this feature is shown in Figures 12-75, 12-76 +and 12-77, with NUMISHEET’02 fender outer, where flanging is conducted along the +hood line. A partial input is provided below, where DTMAX is controlled by a load +curve for contact and speed. The use of DTMAX with a load curve is an exception to +the rule, where most of the time this is not needed. Smaller step sizes are better in some +cases than larger step sizes, which may take longer to converge resulting from cutbacks +in step sizes. Gravity, pad closing and flanging were set to 10%, 10% and 80% of the +total step size, respectively. Pad travels a distance of ‘&padtrav’ starting at 0.1, when it +is to be automatically moved to close the gap with the blank due to gravity loading +(*CONTACT_AUTO_MOVE), and finishing at 0.2 and held in that position until the +end. Flanging steel travels a distance of ‘&flgtrav’ starting at 0.2 and completing at 1.0. +A detailed section view of the simulation follows in Figure 12-78. +*KEYWORD +*PARAMETER ... +*CONTROL_TERMINATION +1.0 +*CONTROL_IMPLICIT_FORMING +$ IOPTION NSMIN NSMAX + 2 2 200 +*CONTROL_IMPLICIT_GENERAL + 1 0.100 +*CONTROL_IMPLICIT_AUTO +$ IAUTO ITEOPT ITEWIN DTMIN DTMAX + 0 0 0 0.005 -9980 +*DEFINE_CURVE +9980 +0.0,0.1 +0.1,0.1 +0.2,0.1 +0.7,0.005 +1.0,0.005 +*CONTROL_ADAPTIVE... +*CONTROL_CONTACT... +*PART... +*SECTION_SHELL... +*CONTACT_... +*CONTACT_FORMING_SURFACE_TO_SURFACE_ID_MPP +2 +0,200,,3,2,1.005 +$ SSID MSID SSTYP MSTYP SBOXID MBOXID SPR MPR + &blksid &padsid 2 2 +$ FS FD DC VC VDC PENCHK BT DT + 0.12 0.0 0.0 0.0 20.0 0 0.0 1E+20 +$ SFS SFM SST MST SFST SFMT FSF VSF + 1.0 1.0 0.0 &mstp +$ SOFT SOFSCL LCIDAB MAXPAR PENTOL DEPTH BSORT FRCFRQ + 0 +$ PENMAX THKOPT SHLTHK SNLOG ISYM I2D3D SLDTHK SLDSTF + 1 +$ IGAP IGNORE DPRFAC DTSTIF FLANGL + 2 +*BOUNDARY_PRESCRIBED_MOTION_RIGID +$ typeID DOF VAD LCID SF VID DEATH BIRTH + &padpid 3 2 3 -1.0 0 + &flgpid 3 2 4 -1.0 0 +*DEFINE_CURVE +3 +0.0,0.0 +0.1,0.0 +0.2,&padtrav +1.0,&padtrav +*DEFINE_CURVE +4 +0.0,0.0 +0.2,0.0 +1.0,&flgtrav +$ Activate gravity on blank: +*LOAD_BODY_PARTS +&blksid +*LOAD_BODY_Z +90994 +*DEFINE_CURVE_TITLE +Body Force on blank +90994 +0.0,9810.0 +10.0,9810.0 +*CONTACT_AUTO_MOVE +$ ID ContID VID LCID ATIME + -1 2 89 3 0.1 +*END +Flanging simulation using IOPTION of 1: +IOPTOIN 1 can also be used for closing and flanging simulation, or other applications +that go through large plastic strains or deformation. This is used when an equal step +size throughout the simulation is desired, and is done by specifying the equal step size +in the variable DT0 in *CONTROL_IMPLICIT_GENERAL, as shown in the following +keywords (other cards similar and not included), where DT0 of 0.014 is chosen. Such an +application is shown in Figures 12-79 and 12-80. +*CONTROL_TERMINATION +1.0 +*CONTROL_IMPLICIT_FORMING +$ IOPTION + 1 +*CONTROL_IMPLICIT_GENERAL +$ IMFLAG DT0 + 1 0.014 +Switching between implicit dynamic and implicit static for gravity loading: +For sheet blank gravity loading, it is now possible to start the simulation using implicit +dynamic method, switching to implicit static method at a user defined time until +completion. This feature is activated by setting the variable TDYDTH in *CONTROL_- +IMPLICIT_DYNAMICS and was recently (Rev. 81400) linked together with *CON- +TROL_IMPLICIT_FORMING. In a partial keyword example below, death time for the +implicit dynamic is set at 0.55 second. The test model shown in Figure 12-81 (left) +results in a gravity loaded blank shape in Figure 12-81 (right). Without the switching, +the blank will look like as shown in Figure 12-82. The gravity loaded blank shape is +more reasonable with the switching. A check on the energy history reveals that the +kinetic energy dissipated completely at 0.60 second, Figure 12-83. +*CONTROL_TERMINATION +1.0 +*CONTROL_IMPLICIT_FORMING +$ IOPTION NSMIN NSMAX BIRTH DEATH PENCHK + 1 +*CONTROL_IMPLICIT_DYNAMICS +$ IMASS GAMMA BETA TDYBIR TDYDTH TDYBUR IRATE + 1 0.600 0.380 0.55 +Revision information: +This implicit capability is available in R5.0 and later releases. This keyword is +implemented in LS-PrePost4.0 eZSetup for metal forming application. +1)Revision 64802: Multi-step gravity loading simulation. +2)Revision 81400: Switching feature between implicit dynamic and implicit static. +3)Revision 104837: variable DT0. + +Time= 1 +Contours of Z-displacement +Original flat sheet blank +after auto-position +Z-displacement +(mm) +Gravity-loaded blank +Binder opening +Lower binder +7.01 +-31.92 +-70.86 +-109.80 +-148.70 +-187.70 +-226.60 +-265.50 +-304.50 +-343.40 +-382.30 +Figure 12-69. Gravity loading on a box side outer toggle die (courtesy of +Autodie, LLC). + Figure 12-70. Initial auto-positioning (NUMISHEET2005 decklid inner). +Figure 12-71. At 50% upper travel. +Figure 12-72. At 80% upper travel. +Figure 12-73. Upper travels to home. +Draw beads +Blank shape upon +binder closing +Upper cavity +Buckles predicted +Blank +Lower binder (with +contact offset of 1.1x +blank thickness) +Figure 12-74. Binder closing with beads on a hood outer. +Section A-A +Figure 12-75. Mean stress at pad closing. +Figure 12-76. Mean stress at 40% Travel. +B +Home (view 1) +Home (view 2) +Figure 12-77. Mean stress at flanging home (compression/surface lows in +red). +Upper pad +Flanging +post +Trimmed +panel +Flanging +steel + Figure 12-78. Flanging progression along section B (flanging post stationary). +Thinning (%) +20.0 +18.0 +16.0 +14.0 +12.0 +10.0 +8.0 +6.0 +4.0 +2.0 + 0.0 +Flanged area in detail next figure +Figure 12-79. Flanging simulation of a rear floor pan using IOPTION 1 +(Courtesy of Chrysler, LLC). +Thinning (%) +20.0 +Pressure (MPa) +294.1 +18.0 +16.0 +14.0 +12.0 +10.0 +8.0 +6.0 +4.0 +2.0 +-0.0 +Thinning contour +235.9 +177.7 +119.5 +61.25 +3.03 +-55.2 +-113.4 +-171.6 +-229.8 +-288.1 +Mean stress contour - +compression in red +Figure 12-80. Localized view of the last figure. +Initial totally flat +sheet blank +Binder +Time=0 +Time=1.0 +Figure 12-81. Test model (left) and gravity loaded blank (right) with +switching from implicit dynamic to implicit static. +Figure 12-82. Gravity loaded blank without the “switching”. +Time=1.0 +25 +20 +15 +10 +) +( +0.0 +t=0.55 t=0.60 +Implicit dynamic +Implicit static +Kinetic energy +Internal energy +Total energy +Kinetic energy dissipates +after a small transition step +0.2 +0.4 +0.6 +0.8 +1.0 +Implicit "time" (sec.) +Figure 12-83. Switching between implicit dynamic and implicit static. +*CONTROL_IMPLICIT_GENERAL_{OPTION} +Availlable option s include: + +DYN +SPR +Purpose: Activate implicit analysis and define associated control parameters. This +keyword is required for all implicit analyses. The DYN option allows setting controls +specifically for the dynamic relaxation phase. The SPR option allows setting controls +specifically for the springback phase. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IMFLAG +DT0 +IMFORM +NSBS +IGS +CNSTN +FORM +ZERO_V +Type +Default +I +0 +F +none +I +2 +I +1 +I +2 +I +0 +I +0 +I +0 + VARIABLE +DESCRIPTION +IMFLAG +Implicit/Explicit analysis type flag +EQ.0: explicit analysis +EQ.1: implicit analysis +EQ.2: explicit followed by implicit, (seamless springback). *IN- +to +is required +TERFACE_SPRINGBACK_SEAMLESS +activate seamless springback. +EQ.4: implicit with automatic implicit-explicit switching +EQ.5: implicit with automatic switching and mandatory +implicit finish +EQ.6: explicit with intermittent eigenvalue extraction +LT.0: curve ID = -IMGFLAG specifies IMFLAG as a function of +time. +DT0 +Initial time step size for implicit analysis +Implicit 1 +Explicit 0 + Figure 12-84. Solution method, implicit or explicit, controlled by a load curve. +Time + VARIABLE +IMFORM +DESCRIPTION +Element formulation flag for seamless springback; see *INTER- +FACE_SPRINGBACK_SEAMLESS. +EQ.1: switch +to +springback +fully +integrated shell +formulation +for +EQ.2: retain original element formulation (default) +NSBS +Number of implicit steps in seamless springback; see *INTER- +FACE_SPRINGBACK_SEAMLESS. +IGS +Geometric (initial stress) stiffness flag +EQ.1: include +EQ.2: ignore +CNSTN +Indicator for consistent tangent stiffness (solid materials 3 & 115 +only): +EQ.0: do not use (default) +EQ.1: use. +FORM +integrated element +Fully +IMFORM = 1 only) +formulation +(IMFLAG = 2 and +EQ.0: type 16 +EQ.1: type 6. +VARIABLE +DESCRIPTION +ZERO_V +Zero out the velocity before switching from explicit to implicit. +EQ.0: The velocities are not zeroed out. +EQ.1: The velocities are set to zero. +Remarks: + VARIABLE +IMFLAG +REMARK +The default value 0 indicates a standard explicit analysis will be +performed. Using value 1 causes an entirely implicit analysis to +be performed. Value 2 is automatically activated when the +keyword *INTERFACE_SPRINGBACK_SEAMLESS is present, +causing the analysis type to switch from explicit to implicit when +the termination time is reached. Other nonzero values for IM- +FLAG can also be used with *INTERFACE_SPRINGBACK_- +SEAMLESS. After this switch, the termination time is extended +by NSBS*DT0, or reset to twice its original value if DT0 = 0.0. The +implicit simulation then proceeds until the new termination time +is reached. Contact interfaces are automatically disabled during +the implicit phase of seamless springback analysis. Furthermore, +implicit stabilization (*CONTROL_IMPLICIT_STABILIZATION) +and automatic step size adjustment (*CONTROL_IMPLICIT_AU- +TO) on by default for seamless springback. +When the automatic implicit-explicit switching option is activated +(IMFLAG = 4 or 5), the solution method will begin as implicit. If +convergence of the equilibrium iterations fails, the solution will +automatically switch to explicit for a time interval of DTEXP . After this time interval, the +solution method will switch back to implicit and attempt to +proceed. The implicit simulation may be either static or dynamic. +When this feature is used in a static implicit job, simulation time +is no longer arbitrary, and must be chosen along with DTEXP in a +realistic way to allow efficient execution of any explicit phases. +Mass scaling may also be activated , +and will apply only during the explicit phases of the calculation. +In cases where much switching occurs, users must exercise +caution to ensure that negligible dynamic effects are introduced +by the explicit phases. +When IMFLAG = 5, the final step of the simulation must be +implicit. The termination time will be extended automatically as +necessary, until a successfully converged implicit step can be +VARIABLE +REMARK +obtained. This is useful for example in difficult metal forming +springback simulations. +When IMFLAG = 6, an explicit simulation will be performed. +Eigenvalues will be extracted intermittently according to a curve +indicated by NEIG=(-curve ID) on *CONTROL_IMPLICIT_- +EIGENVALUE. Beware that dynamic stress oscillations which +may occur in the explicit simulation will influence the geometric +(initial stress) stiffness terms used +in the eigen solution, +potentially producing misleading results and/or spurious modes. +As an alternative, eigenvalues can also be extracted intermittently +during an implicit analysis, using IMFLAG = 1 and NEIG=(-curve +ID). +When IMFLAG < 0, a curve ID is indicated which gives the +solution method as a function of time. Define a curve value of +zero during explicit phases, and a value of one during implicit +phases. Use steeply sloping sections between phases. An +arbitrary number of formulation switches may be activated with +this method. See Figure 12-84. +This parameter selects the initial time step size for the implicit +phase of a simulation. The step size may change during a +multiple step simulation if the automatic time step size control +feature is active +Adaptive mesh must be activated when using element +formulation switching. For best springback accuracy, use of shell +type 16 is recommended during the entire stamping and +springback analysis, in spite of the increased cost of using this +element during the explicit stamping phase. +The NSBS option allows a seamless springback analysis, invoked +with *INTERFACE_SPRINGBACK_SEAMLESS, to use multiple +unloading steps. Implicit seamless springback beings at time, +𝑡 = ENDTIM and finishes at 𝑡 = ENDTIM + NSBS × DT0 were +ENDTIM is specified in *CONTROL_TERMINATION and DT0 is +specified in *CONTROL_IMPLICIT_GENERAL. +The geometric stiffness adds the effect of initial stress to the +global stiffness matrix. This effect is seen in a piano string whose +natural frequency changes with tension. Geometric stiffness does +not always improve nonlinear convergence, especially when +DT0 +INFORM +NSBS +IGS +VARIABLE +REMARK +compressive stresses are present, so its inclusion is optional. +Furthermore, the geometric stiffness may lead to convergence +incompressible, +incompressible, or nearly +problems with +materials. +*CONTROL_IMPLICIT_INERTIA_RELIEF +Purpose: Allows analysis of linear static problems that have rigid body modes. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IRFLAG +THRESH +IRCNT +Type +Default +I +0 +F +0.001 +I +0 +Additional Mode List Cards. This card should be included only when the user wants +to specify the modes to use. Include as many cards as needed to provide all values. +This input ends at the next keyword (“*”) card. The mode numbers do not have to be +consecutive. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable MODE1 MODE2 MODE3 MODE4 MODE5 MODE6 MODE7 MODE8 +Type +I +I +I +I +I +I +I +I + VARIABLE +DESCRIPTION +IRFLAG +Inertia relief flag +EQ.0: do not perform inertia relief +EQ.1: do perform inertia relief +THRESH +Threshold for what is a rigid body mode. The default is set to +0.001 Hertz where it is assumed that the units are in seconds. +IRCNT +MODEi +The user can specify to use the lowest IRCNT modes instead of +using THRESH to determine the number of modes. +Ignore THRESH and IRCNT and use a specific list of modes, +skipping those that should not be used. +*CONTROL +Purpose: Specify penalty or constraint treatment of joints for implicit analysis. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ISPHER +IREVOL +ICYLIN +Type +Default +I +1 +I +1 +I +1 + VARIABLE +DESCRIPTION +ISPHER +Treatment of spherical joints +EQ.1: use constraint method for all spherical joints (default) +EQ.2: use penalty method for all spherical joints +IREVOL +Treatment of revolute joints +EQ.1: use constraint method for all revolute joints (default) +EQ.2: use penalty method for all revolute joints +ICYLIN +Treatment of cylindrical joints +EQ.1: use constraint method for all cylindrical joints (default) +EQ.2: use penalty method for all cylindrical joints +Remarks: +For most implicit applications one should use the constraint (default) method for the +treatment of joints. When explicit-implicit switching is used the joint treatment should +be consistent. This keyword allows the user to choose the appropriate treatment for +their application. +*CONTROL_IMPLICIT_MODAL_DYNAMIC +Purpose: Activate implicit modal dynamic analysis. Eigenmodes are used to linearize +the model by projecting the model onto the space defined by the eigenmodes. The +eigenmodes can be computed or read from a file. All or some of the modes can be used +in the linearization. Modal damping can be applied. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable MDFLAG +ZETA +Type +I +F +Optional Filename Card. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +FILENAME +A80 + VARIABLE +DESCRIPTION +MDFLAG +Modal Dynamic flag +EQ.0: no modal dynamic analysis +EQ.1: perform modal dynamic analysis. +ZETA +Modal Dynamic damping constant. +FILENAME +If specified the eigenmodes are read from the specified file. +Otherwise the eigenmodes are computed as specified on *CON- +TROL_IMPLICIT_EIGENVALUE. +Remarks: +Modal Dynamic uses the space spanned by the eigenmodes of the generalized +eigenvalue problem +The matrix of eigenmodes, 𝚽, diagonalizes 𝐊 and 𝐌 +𝐊𝛟𝑖 = 𝜆𝑖𝐌𝛟𝑖. +𝚽𝐓𝐊𝚽 = 𝚲 +and + 𝚽𝐓𝐌𝚽 = 𝐈. +Multiplication by 𝜱 changes coordinates from amplitude space to displacement space +as +where 𝒂 is a vector of modal amplitudes. The equations of motion +𝐌𝐮̈𝑛+1 + 𝐊𝚫𝐮 = 𝐅(𝐱𝒏) +𝐮 = 𝚽𝐚 +when multiplied on the left by 𝛟T and substituting 𝐮 = 𝚽𝐚 become the linearized +equations of motion in its spectral form as, +𝐈𝐚̈𝑛+1 + 𝚲(𝚫𝐚) = 𝚽T𝐅(𝐱𝑛). +The modal damping features adds a velocity dependent damping term, +𝐈𝐚̈𝑛+1 + 2𝐙𝐚̇𝑛 + 𝚲(𝚫𝐚) = 𝚽T𝐅(𝐱𝒏) +Where 𝑍𝑖𝑖 = 𝜁𝑖𝜔𝑖, 𝜔𝑖 = √𝜆𝑖, and each 𝜁𝑖 is a user specified damping coefficients. +The matrices in the reduced equations are diagonal and constant. So Modal Dynamics +can quickly compute the acceleration of the amplitudes and hence the motion of the +model. But the motion is restricted to the space spanned by the eigenmodes. +Eigenmodes are either computed based on *CONTROL_IMPLICIT_EIGENVALUE or +read from file FILENAME. By default all modes are used in the projection. Selected +modes can be specified via *CONTROL_IMPLICIT_MODAL_DYNAMIC_MODE to +reduce the size of the projection. . +Stresses are computed only for linear shell formulation 18 and linear solid formulation +18. +Modal damping on all modes can be specified using ZETA. More options for specifying +modal damping can be found on *CONTROL_IMPLICIT_MODAL_DYNAMIC_DAMP- +ING. +Using MDFLAG = 1, ZETA = 0.0, and FILENAME = “ ” is the same as using IMASS = 2 +with *CONTROL_IMPLICIT_DYNAMICS. Using MDFLAG = 1, ZETA = 0.0 and FILE- +NAME = ’d3eigv’ is the same as IMASS = 3. The new keywords *CONTROL_IMPLIC- +IT_MODAL_DYNAMIC_MODE and *CONTROL_IMPLICIT_MODAL_DYNAMIC_- +DAMPING provide additional user options for mode selection and modal damping. +*CONTROL_IMPLICIT_MODAL_DYNAMIC_DAMPING_{OPTION} +Available options include: +BLANK +SPECIFIC +FREQUENCY_RANGE +Purpose: Define vibration modes to be used in implicit modal dynamic. +Damping Card. Card for option set to . + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ZETA1 +Type +F +I +Specific Damping Cards. Cards for the SPECIFIC option. This input ends at the next +keyword (“*”) card. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID1 +ZETA1 +MID2 +ZETA2 +MID3 +ZETA3 +MID4 +ZETA4 +Type +I +F +I +F +I +F +I +F +Frequency Range Damping Cards. Cards for FREQUENCY_RANGE option. This +input ends at the next keyword (“*”) card. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FREQ1 +ZETA1 +FREQ2 +ZETA2 +FREQ3 +ZETA3 +FREQ4 +ZETA4 +Type +F +F +F +F +F +F +F +F +VARIABLE +DESCRIPTION +ZETAn +Modal Dynamic damping coefficient n. +MIDn +Mode ID n. +f1 +f2 f3 +f4 +f5 +frequency +Figure 12-85. Schematic illustration of frequency range damping. +VARIABLE +DESCRIPTION +FREQn +Frequency value n. +Remarks: +1. +2. +3. +If no option is specified the value of ZETA1 becomes the damping coefficient +for all modes involved in implicit modal dynamic analysis. This value over- +rides the value on *CONTROL_IMPLICIT_MODAL_DYNAMIC. +If option SPECIFIC is specified the integers MIDn indicate which modes +involved in *CONTROL_IMPLICIT_MODAL_DYNAMIC will have modal +damping applied to them. The associated value ZETAn will be the modal +damping coefficient for that mode. +If option FREQUENCY_RANGE is specified all modes involve will have modal +damping applied. The damping coefficient will be computed by linear interpo- +lation of the pairs (FREQi, ZETAi). If the modal frequency is less than FREQ1 +then the modal damping coefficient will be ZETA1. If the modal frequency is +greater than FREQn then the modal damping coefficient will be ZETAn. The +values of FREQi must be specified in ascending order. +*CONTROL_IMPLICIT_MODAL_DYNAMIC_MODE_OPTION +Available options include: +LIST +GENERATE +Purpose: Define vibration modes to be used in implicit modal dynamic. +Mode ID Cards. Card 1 for the LIST keyword option. For each mode include an +addition. This input ends at the next keyword (“*”) card. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MID1 +MID2 +MID3 +MID4 +MID5 +MID6 +MID7 +MID8 +Type +I +I +I +I +I +I +I +I +Mode Range Cards. Card 1 for the GENERATE keyword option. For each range of +modes include an additional card. This input ends at the next keyword (“*”) card. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable M1BEG M1END M2BEG M2END M3BEG M3END M4BEG M4END +Type +I +I +I +I +I +I +I +I + VARIABLE +DESCRIPTION +MIDn +Mode ID n. +MnBEG +First mode ID in block n. +MnEND +Last mode ID in block n. All mode ID’s between and including +MnBEG and MnEND are added to the list. +Remarks: +1. User may use this keyword with *CONTROL_IMPLICIT_MODAL_DYNAMIC +if some of the vibration modes have less contribution to the total structural +response and can be removed from the implicit modal dynamic analysis. +*CONTROL_IMPLICIT_MODES_{OPTION} +Available options include: + +BINARY +Purpose: Request calculation of constraint, attachment, and/or eigenmodes for later +use in modal analysis using *PART_MODES or *ELEMENT_DIRECT_MATRIX_INPUT. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NSIDC +NSIDA +NEIG +IBASE +SE_MASS SE_DAMP SE_STIFF SE_INERT +I +0 +2 +Type +Default +I +0 + Card 2 +1 +Variable +Type +I +I +C +C +C +C +3 +4 +5 +6 +7 +8 +SE_FILENAME +C + VARIABLE +DESCRIPTION +NSIDC +Node set ID for constraint modes +EQ.0: no constraint modes will be generated +NSIDA +Node set ID for attachment modes +EQ.0: no attachment modes will be generated +NEIG +Number of eigenmodes (normal modes) +EQ.0: no eigenmodes will be generated +IBASE +Offset for numbering of the generalized internal degrees of +freedom for the superelement +SE_MASS +*CONTROL_IMPLICIT_MODES +DESCRIPTION +Name of the superelement mass matrix. If left blank it is not +generated. +SE_DAMP +Name of the superelement damping matrix. If left blank it is not +generated. +SE_STIFF +Name of the superelement stiffness matrix. If left blank it is not +generated. +SE_INERT +Name of the superelement inertia matrix, required for gravity +loading applications of the superelement. If left blank it is not +generated. +SE_FILENAME +If any of SE_MASS, SE_DAMP, SE_STIFF, or SE_INERT are not +blank then the second line is required and contains the file name +for the superelement. +Remarks: +To use this feature, an implicit analysis must be requested using IMFLAG = 1 on *CON- +TROL_IMPLICIT_GENERAL, and a non-zero termination time must be specified on +*CONTROL_TERMINATION. A double precision version of LS-DYNA should be used +for best accuracy. Care must be taken to apply a sufficient number of constraints to the +model to eliminate static rigid body motion. Computed modes are written to binary +output file d3mode, with the order of output being constraint modes, followed by +attachment modes, and then eigenmodes. The d3mode file can be read and modes +viewed using LS-PrePost. Eigenmodes are also written to binary output file d3eigv. +Constraint and attachment modes are generated by applying unit displacements and +unit forces, respectively, to each specified degree of freedom. By default, modes are +computed for all degrees of freedom for each node in sets NSIDC and NSIDA. The first +and second node set attribute parameters can be optionally used to restrict the +translational and rotational degrees of freedom for which modes are requested, +respectively, according to the following syntax: +Node set attribute parameters DA1 and A1: translational degree of freedom codes +Node set attribute parameters DA2 and A2: rotational degree of freedom codes +code modes computed + +X degree of freedom only +Y degree of freedom only +0 +1 +3 +4 +5 +6 +7 +Z degree of freedom only +X, Y degrees of freedom only +Y, Z degrees of freedom only +X, Z degrees of freedom only +X, Y, Z degrees of freedom +Setting both node set attributes to zero is equivalent to setting both node set attributes +to 7 (X, Y, and Z for translational and rotational degrees of freedom). +If one node set attribute is nonzero (codes 1 to 7) and the other node set attribute is zero, +then the zero attribute means NO degrees of freedom are considered. For example, if +DA1 = 2 and DA2 = 0, then only the Y-translational degree of freedom modes are +calculated. +Eigenmodes are generated for the model with single point constraints applied on the +constraint modes. The number of eigenmodes is specified here. If the user wants to +compute eigenmodes other than the lowest ones, the controls on *CONTROL_IMPLIC- +IT_EIGENVALUE can be used. +When the superelement is created an internal numbering must be applied to the +attachment and eigen modes. This numbering starts at IBASE+1. +The user can create the superelement representation of the reduced model by specifying +the SE_MASS, SE_DAMP, SE_STIFF, SE_INERT and SE_FILENAME fields. The inertia +matrix is necessary if body forces, e.g., gravity loads, are applied to the superelement. +The file, by default is written in the Nastran DMIG file format and can be used as input +to *ELEMENT_DIRECT_MATRIX_INPUT. The BINARY keyword option can be used +to create a binary representation for the superelement which can be used with *ELE- +MENT_DIRECT_MATRIX_INPUT_BINARY to reduce the file size. +The combination of constraint modes and eigenmodes form the Hurty-Craig-Bampton +linearization for a model. Using only constraint modes is the same as static +condensation. +Some broad guidelines for appropriate selection of constraint modes, attachment +modes, and eigenmodes include: +1. Use constraint modes for the nodal degrees-of-freedom that are to be "con- +strained" with SPCs or prescribed motion. +2. Use attachment modes for nodal degrees-of-freedom that are under the +influence of point loads. +3. Use eigenmodes in the construction of the superelement to capture the reaction +of the part being modeled by the superelement and the associated feedback to +the rest of the model. +*CONTROL_IMPLICIT_ROTATIONAL_DYNAMICS +Purpose: This keyword is used to model rotational dynamics using the implicit time +integrator. Applications for this feature include the transient and vibration analysis of +rotating parts such as turbine blades, propellers in aircraft, and rotating disks in hard +disk drives. The current implementation requires a double-precession SMP version of +LS-DYNA. An MPP implementation is under development. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SID +STYPE +OMEGA +VID +NOMEG +IREF +OMEGADR +Type +I +Default +none +I +0 +F +I +none +none +I +0 +I +0 +F +0 +Additional Rotational Speed Cards. This card should be included only when +NOMEG > 0. Include as many cards as needed to provide all NOMEG values. This +input ends at the next keyword (“*”) card. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +OMEG1 +OMEG2 +OMEG3 +OMEG4 +OMEG5 +OMEG6 +OMEG7 +OMEG8 +Type +F +F +F +F +F +F +F +F + VARIABLE +DESCRIPTION +SID +Set ID of the rotational components. +STYPE +Set type: +EQ.0: Part; +EQ.1: Part set. +OMEGA +Rotating speed. +GT.0: rotating speed. +LT.0: curve ID = (-OMEGA) gives rotating speed as a function +of time. +VID +*CONTROL_IMPLICIT_ROTATIONAL_DYNAMICS +DESCRIPTION +Vector ID to define the rotating axis. It can be defined in *DE- +FINE_VECTOR and *DEFINE_VECTOR_NODES, and the tail of +the vector should be set as the rotating center. +NOMEG +Number of rotating speeds. + This feature is intended to +automatically preform parameter studies with respect to the +rotation speed. The keyword *CONTROL_IMPLICIT_EIGEN- +VALUE must be included if NOMEG > 0. +IREF +Reference frame: +EQ.0: Rotating coordinate system and rotating parts will not +rotate in visualization. Solid element and thick shell +element will use IREF = 0. +EQ.1: Fixed coordinate system. Rotating parts rotates and the +initial rotating velocity should be defined in *INITIAL_- +VELOCITY_GENERATION as well. +EQ.2: Rotating coordinate system, but rotate rotating parts for +visualization purpose. +OMEGn +The nth rotating speed. +OMEGADR +Rotating speed defined in dynamic relaxation. +GT.0: rotating speed defined in dynamic relaxation. +LT.0: curve ID = (-OMEGA) gives rotating speed as a function +of time. +Remarks: +The linearized equilibrium equation in the rotating coordinate system is given by +Whereas, in a fixed coordinate system, the linearized equilibrium equation is +𝐌𝐮̈ + (𝐃 + 2Ω𝐂)𝒖̇ + (𝑲 − Ω2𝐊𝐺)𝐮 = 𝐅 +𝐌𝐮̈ + (𝐃 + Ω𝐂)𝐮̇ + 𝐊𝐮 = 𝐅 +with +𝐌 = lumped mass matrix +𝐃 = damping matrix +𝐊 = stiffness matrix +𝐂 = gyroscopic matrix +𝐊𝐺 = centrifugal stiffness matrix +𝐮 = nodal displacement vector +𝐮̇ = nodal point velocities at time +𝐮̈ = nodal point acceleration at time +Ω = rotating speed +The chief difference between the equations for the rotating and fixed frames is the +inclusion of the centrifugal stiffness matrices𝐊𝑔. Additionally, the coefficient on the +gyroscopic matrix, 𝐂, as well as its content are modified in the rotating-frame case. +Specifically, the rotating system includes an additional Coriolis contribution to 𝐂. +In many applications of rotational dynamics, the critical speed – the theoretical angular +velocity that excites the natural frequency of a rotating object – is of particular concern. +Therefore, the study of mode frequency response with the change of the rotating speed +is very important. The Campbell diagram, which is defined to represent a system’s +eigen-frequencies as a function of rotating speeds, is introduced for this purpose. In +order to do this, the user needs to define a set of rotating speeds on card 2, and LS- +DYNA will do modal analysis for each of these speeds. NOMEG should be defined as +the number of rotating speeds used in card 2. A keyword file example in this +application can be set as follows: +*KEYWORD +*CONTROL_TERMINATION... +*CONTROL_IMPLICIT_EIGENVALUE + 5 +*CONTROL_IMPLICIT_GENERAL + 1 0.05 +*CONTROL_IMPLICIT_ROTATIONAL_DYNAMICS +$# SID STYPE OMEGA VID NOMEGA IREF + 1 0 0.0 1 4 1 +$# OMEG1 OMEG2 OMEG3 OMEG4 + 50.0 100.0 150.0 200.0 +*DEFINE_VECTOR +$# VID XT YT ZT XH YH ZH CID + 1 0.0 0.0 0.0 1.0 0.0 0.0 +*DATABASE_... +*PART... +*SECTION... +*MAT... +*ELEMENT... +*NODE... +*END +Besides of modal analysis, transient analysis can also be done using this keyword. A +keyword file example can be set as follows: +*KEYWORD +*CONTROL_TERMINATION... +*CONTROL_IMPLICIT_GENERAL + 1 0.05 +*CONTROL_IMPLICIT_ROTATIONAL_DYNAMICS +$# SID STYPE OMEGA VID NOMEGA IREF + 1 0 0.0 1 0 0 +*DEFINE_VECTOR +$# VID XT YT ZT XH YH ZH CID + 1 0.0 0.0 0.0 1.0 0.0 0.0 +*DATABASE_... +*PART... +*SECTION... +*MAT... +*ELEMENT... +*NODE... +*END +*CONTROL_IMPLICIT_SOLUTION_{OPTION} +Available options include: + +DYN +SPR +Purpose: These optional cards apply to implicit calculations. Use these cards to specify +whether a linear or nonlinear solution is desired. Parameters are also available to +control the implicit nonlinear and arc length solution methods . The DYN option allows setting controls specifically for the +dynamic relaxation phase. The SPR option allows setting controls specifically for the +springback phase. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NSOLVR +ILIMIT MAXREF +DCTOL +ECTOL +RCTOL +LSTOL +ABSTOL +Type +I +I +I +F +F +F +F +F +Default +12 +11 +15 +0.001 +0.01 +1010 +0.90 +10-10 +Remaining cards are optional.† + Optional +2a +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DNORM +DIVERG +ISTIF +NLPRINT NLNORM D3ITCTL +CPCHK +Type +Default +I +2 +I +1 +I +1 +I +0 +F/I +2 +I +0 +I +0 +Strict Tolerances Optional Card. Define this card if and only if DNORM.LT.0 +Optional +2b +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DMTOL +EMTOL +RMTOL +NTTOL +NRTOL +RTTOL +RRTOL +Type +F +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Arc Length Optional Card. The contents of this card are ignored unless an arc-length +method is activated (6 ≤ NSOLVR ≤ 9, or NSOLVR = 12 and ARCMTH = 3). +Optional 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ARCCTL +ARCDIR +ARCLEN ARCMTH ARCDMP +ARCPSI +ARCALF +ARCTIM +Type +Default +I +0 +I +none +F +0 +I +1 +I +2 +F +0. +F +0. +F +0. +Line Search Parameter Optional Card. +Optional 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LSMTD +LSDIR +IRAD +SRAD +AWGT +SRED +Type +Default +I +4 +I +2 +F +F +F +F +0.0 +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +NSOLVR +Solution method for implicit analysis: +EQ.1: Linear +EQ.12: Nonlinear with BFGS updates + optional arclength, +(default) incorporating different line search and inte- +gration schemes compared to solver 2. +EQ.2: Nonlinear with BFGS updates (obsolete) +VARIABLE +DESCRIPTION +EQ.3: Nonlinear with Broyden updates +EQ.4: Nonlinear with DFP updates +EQ.5: Nonlinear with Davidon updates +EQ.6: Nonlinear with BFGS updates + arclength +EQ.7: Nonlinear with Broyden updates + arclength +EQ.8: Nonlinear with DFP updates + arclength +EQ.9: Nonlinear with Davidon updates + arclength +ILIMIT +Iteration limit between automatic stiffness reformations +MAXREF +Stiffness reformation limit per time step. +LT.0: If |MAXREF| matrix reformations occur convergence for +that time step is forced, see REMARKS. +DCTOL +Displacement relative convergence tolerance +ECTOL +Energy relative convergence tolerance +RCTOL +Residual (force) relative convergence tolerance (DEFAULT = +inactive) +LSTOL +Line search convergence tolerance +ABSTOL +Absolute convergence tolerance. +LT.0: Convergence detected when the residual norm is less +than –ABSTOL (Tip: To drive convergence based on – +ABSTOL, set DCTOL and ECTOL to 1.0E-20) +DNORM +Displacement norm for convergence test +EQ.1: Increment vs. displacement over current step +EQ.2: Increment vs. total displacement (default) +If DNORM.LT.0, this is to be interpreted as its absolute value, but +activates reading of optional card 2b. +DIVERG +Divergence flag (force imbalance increase during equilibrium +iterations) +EQ.1: reform stiffness if divergence detected (default) +VARIABLE +DESCRIPTION +EQ.2: ignore divergence +ISTIF +Initial stiffness formation flag +EQ.1: reform stiffness at start of each step (default) +EQ.n: reform stiffness at start of every “n”th step +NLPRINT +Nonlinear solver print flag +EQ.0: no nonlinear iteration information printed (new v970 +default) +EQ.1: print iteration information to screen, message, d3hsp +files +EQ.2: print extra norm information (NLNORM = 1) +EQ.3: same as 2, but also print information from line search + NOTE: during execution, interactive commands can be used: +response +toggle NLPRINT between 0 and 1 +toggle NLPRINT between 0 and 2 +interactive command + nlprint + diagnostic + information +set NLPRINT = 2 for one iteration +NLNORM +Nonlinear convergence norm type, input an integer if zero or a +positive number is used and float if a negative value is used +LT.0: Same as 4, but rotational degrees of freedom are scaled +appropriately with characteristic length |NLNORM| to +account for units. See remarks. +EQ.1: consider translational and rotational degrees of freedom +EQ.2: consider translational degrees of freedom only (default) +EQ.4: consider sum of translational and rotational degrees of +freedom, i.e., no separate treatment. See remarks. +D3ITCTL +Control d3iter database. If nonzero, the search directions for the +nonlinear implicit solution are written to the d3iter database. To +reduce the size of the d3iter database the database is reset every n +time steps where n = d3itctl. +CPCHK +Contact penetration check flag. This flag does not apply to +mortar contacts. +EQ.0: no contact penetration check is performed (default). +VARIABLE +DESCRIPTION +DMTOL +EMTOL +RMTOL +NTTOL +NRTOL +RTTOL +RRTOL +EQ.1: check for contact penetration during the nonlinear +solution procedure. If such penetration is found modify +the line search to prevent unnecessary penetration. +Maximum displacement convergence tolerance, convergence is +detected when the relative maximum nodal or rigid body +displacement is less than this value +Maximum energy convergence tolerance, convergence is detected +when the relative maximum nodal or rigid body energy increment +is less than this value +is +Maximum residual convergence +detected when the relative maximum nodal or rigid body residual +is less than this value +tolerance, convergence +translational convergence +is +Nodal +detected when the absolute maximum nodal translational residual +is less than this value +tolerance, convergence +Nodal rotational convergence tolerance, convergence is detected +when the absolute maximum nodal rotational residual is less than +this value +Rigid body translational convergence tolerance, convergence is +detected when the absolute maximum rigid body translational +residual is less than this value +Rigid body rotational convergence tolerance, convergence is +detected when the absolute maximum rigid body rotational +residual is less than this value +ARCLEN +Relative arc length size. See remarks below. +LE.0.0: use automatic size, +GT.0.0: use ARCLEN × (automatic step size). +ARCMTH +Arc length method +EQ.1: Crisfield (default) +EQ.2: Ramm +EQ.3: Modified Crisfield (used with NSOLVR = 12 only) +ARCDMP +Arc length damping option +VARIABLE +DESCRIPTION +EQ.2: off (default) +EQ.1: on, oscillations in static solution are suppressed +ARCPSI +ARCALF +Relative influence of load/time parameter in spherical arclength +constraint, default value is 0 which corresponds to a cylindrical +arclength constraint. Applies to ARCMTH = 3. +Relative influence of predictor step direction for positioning of +the arc center, default is 0 which means that the center is at the +origin. Applies to ARCMTH = 3. +ARCTIM +Optional time when arclength method is initiated. Applies to +ARCMTH = 3. +LSMTD +Line search convergence method: +EQ.1: Energy method using only translational variables +EQ.2: Residual method +EQ.3: Energy method using both translational and rotational +variables +EQ.4: Energy method using sum of translational and rotational +degrees of freedom (default), i.e., no separate treatment +EQ.5: Same as 4, but account for residual norm growth to be +extra conservative in step length +EQ.6: Same as 5, but minimizes the residual norm whenever +convenient. +LSDIR +Line search direction method: +EQ.1: Search on all variables (traditional approach used in +versions prior to 971) +EQ.2: Search only on +the +independent +(unconstrained) +variables +EQ.3: Use adaptive line search +EQ.4: Use curved line search +IRAD +Normalized curvature factor for curved line search, where 0 +indicates a straight line search and 1 indicates full curved line +search. +SRAD +Radius of influence for determining curve in curved line search. +VARIABLE +DESCRIPTION +For each independent node, all nodes within this radius are used +for determining the curve. If 0, then all nodes connected to the +same element as the independent node are used. +AWGT +SRED +Adaptive line search weight factor between 0 and 1. A high value +tends to restrict the motion of oscillating nodes during the +implicit process. +Initial step reduction between 0 and 1 for adaptive line search, +use large number for conservative start in implicit procedure. +Remarks: + VARIABLE +NSOLVR +ILIMIT +REMARKS +If a linear analysis is selected, equilibrium checking and +iterations are not performed. +The Full Newton nonlinear solution method can be invoked by +using the default BFGS solver, and selecting ILIMIT = 1 to form +a new stiffness matrix every iteration. +In the neighborhood of limit points the Newton based iteration +schemes often fail. The arc length method of Riks and +Wempner (combined here with the BFGS method) adds a +constraint equation to limit the load step to a constant "arc +length" in load-displacement space. This method is frequently +used to solve snap through buckling problems. When applying +the arc-length method, the curves that define the loading +should contain only two points, and the first point should be at +the origin (0,0). LS-DYNA will extrapolate, if necessary, to +determine the load. In this way, time and load magnitude are +related by a constant. It is possible that time can become +negative in case of load reversal. The arc length method cannot +be used in a dynamic analysis. +In the default BFGS method, the global stiffness matrix is only +reformed every ILIMIT iterations. Otherwise, an inexpensive +stiffness update is applied. By setting ILIMIT = 1, a stiffness +reformation is performed every iteration. This is equivalent to +the Full Newton method (with line search). A higher value of +ILIMIT (20-25) can reduce the number of stiffness matrix +reformations and factorizations which may lead to a significant +reduction in cost. Note that the storage requirements for +VARIABLE +REMARKS +MAXREF +DCTOL +ECTOL +RCTOL +DMTOL, etc. +implicit include storing 2 vectors per iteration. Large values of +ILIMIT will cause substantial increase in storage requirements. +The nonlinear equilibrium search will continue until the +stiffness matrix has been reformed |MAXREF| times, with ILIMIT +iterations between each reformation. If equilibrium has not +been found and MAXREF > 0, control will be passed to the +automatic time step controller if it is activated. If the automatic +time step controller is not active error termination will result. +When the auto time step controller is active, it is often efficient +to choose MAXREF = 5 and try another stepsize quickly, rather +than wasting too many iterations on a difficult step. +When MAXREF < 0 and |MAXREF| matrix reformations have +occurred convergence for the current time step is declared, with +a warning, and the simulation moves to the next time step. This +option should be used with caution as the results for that +particular time step may be wrong. +When the displacement norm ratio is reduced below DCTOL, +this condition is satisfied. Smaller numbers lead to more +accurate determination of equilibrium and, on the negative side, +result in more iterations and higher costs. Use NLPRINT to +display norm data each iteration. +When the energy norm ratio is reduced below ECTOL, this +condition is satisfied. Smaller numbers lead to more strict +determination of equilibrium and, on the negative side, result in +more iterations and higher costs. Use NLPRINT to display +norm data each iteration. +When the residual norm ratio is reduced below RCTOL, this +condition is satisfied. Smaller numbers lead to more strict +determination of equilibrium and, on the negative side, result in +more iterations and higher costs. By default this convergence +criterion is effectively disabled using RCTOL = 1.e10. Use +NLPRINT to display norm data each iteration. +For all nonzero values of the strict tolerance parameters in +optional card 2b, the associated criterion must be satisfied in +addition to the ones defined through DCTOL, ECTOL and +RCTOL. These criteria are based on the maximum norm, which +is regarded as stronger than the Euclidian norm used for the +other parameters, and using them will likely result in higher +VARIABLE +REMARKS +accuracy at the price of more iterations. For NLPRINT.GE.2 a +table is listed in the message and d3hsp for each iteration, +providing the values associated with all the criteria activated. +The first three (DMTOL, EMTOL and RMTOL) of these extra +parameters are unitless and honor the meaning of both +DNORM and NLNORM. The last four (NTTOL, NRTOL, +RTTOL and RRTOL) are to be given in units force, torque, force +and torque, respectively, and the values used should account +for the representative loads in the problem as well as the +discretization size. +A line search is performed on stiffening systems to guard +against divergence of Newton-based nonlinear solvers. With +the Full Newton method, it is sometimes helpful to define a +large value (LSTOL = 9999.0) to effectively disable line search. +When computing the displacement ratio, the norm of the +incremental displacement vector is divided by the norm of +“total” displacement. This “total” displacement may be either +the total over the current step, or the total over the entire +simulation. The latter tends to be more lax, and can be poor at +the end of simulations where large motions develop. For these +is DNORM = 1, and +problems, an effective combination +DCTOL = 0.01 or larger. +By default, a new stiffness matrix is formed whenever +divergence (growing out-of-balance force) is detected. This flag +can be used to suppress this stiffness reformation. +By default, a new stiffness matrix is formed at the start of every +time step. Suppressing this stiffness reformation can decrease +the cost of simulations which have many tiny steps that are +mostly linear, such as transient dynamics. +This flag controls printing of displacement and energy +convergence measures during the nonlinear equilibrium search. +If convergence difficulty occurs, this information is helpful in +determining the problem. +By default, only translational degrees of freedom are used in +evaluating convergence norms. Use this flag to include +rotational degrees of freedom, or to make additional data +available for diagnosing convergence problems. +LSTOL +DNORM +DIVERGE +ISTIF +NLPRINT +NLNORM +VARIABLE +REMARKS +This additional data includes the worst offending node and +degree of freedom contributing to each norm. Rotational +degrees of freedom can be considered independently from the +translational degrees of freedom, meaning that two separate +scalar products are used for evaluating norms, 〈𝐮, 𝐯〉t = 𝐮T𝐉t𝐯 +and 〈𝐮, 𝐯〉r = 𝐮T𝐉r𝐯. Here 𝐉t and 𝐉r are diagonal matrices with +ones on the diagonal to extract the translational and rotational +degrees of +the option +NLNORM = 1, and the convergence criteria must be satisfied +for both translational and rotational degrees of freedom +simultaneously. +freedom, respectively. + This +is +Alternatively they can be included by defining the single scalar +product 〈𝐮, 𝐯〉 = 〈𝐮, 𝐯〉t + 𝜆𝑢𝜆𝑣〈𝐮, 𝐯〉r, where 𝜆𝑢 and 𝜆𝑣 are scale +factors to account for different units of the rotational degrees of +freedom. For NLNORM = 4 these scale factors are equal to 1, +but for NLNORM < 0 𝜆𝑢 is equal to |NLNORM| if u is a +displacement vector and |NLNORM|−1 if it is a force vector, and +the same goes for the pair 𝜆𝑣 and 𝐯. So |NLNORM| is a +characteristic length that appropriately weighs translational and +rotational degrees of freedom together. +The arc length method can be controlled based on the +displacement of a single node in the model. For example, in +dome reversal problems the node at the center of the dome can +be used. By default, the generalized arc length method is used, +where the norm of the global displacement vector controls the +solution. This includes all nodes. +In many cases the arc length method has difficulty tracking the +load displacement curve through critical regions. + Using +0 < ARCLEN < 1 will reduce the step size to assist tracking the + Use of +load-displacement curve with more accuracy. +ARCLEN < 1 will cause more steps to be taken. Suggested +values are 1.0 (the default), 0.5, 0.25, and 0.10. +Some static problems exhibit oscillatory response near +instability points. This option numerically suppresses these +oscillations, and may improve the convergence behavior of the +post-buckling solution. +ARCCTL +ARCLEN +ARCDMP +LMSTD +The default method for determining convergence of the +nonlinear line search is to find the minimum of the energy. This +VARIABLE +REMARKS +LSDIR +IRAD / SRAD +parameter allows choosing the energy on only the translational +variables, energy of both the translational and rotational +variables, or for minimizing the residual (forces). The effect of +using a residual based line search is not always positive, +sometimes it is too restrictive and stops convergence. However, +it is a more conservative approach than using the energy based +method since it explicitly controls the norm of the residual. It +should not be seen as a better strategy than the energy method +but as an alternative to try in cases when the default method +seems to be working poorly. Line search methods 5 and 6 are +conservative line search methods to be used for highly +nonlinear problems, these should not be used as default but as +final resorts to potentially resolve convergence issues. The rule +of thumb is that the LSMTD = 5 is slow but robust and +LSMTD = 6 is even slower but more robust. +In Version 971 of LS-DYNA new line search options were +added. The traditional approach (LSDIR = 1) computes the line +search direction using all variables. The new (default) approach +of LSIDR = 2 computes the line search direction only on the +unconstrained variables. It has proven to be both robust and +more efficient. We have also included two new approaches to +try for problems where the default and traditional approach fail +and the user is using Full Newton (ILIMIT = 1). See the next +two remarks for more information on those methods. +The parameters IRAD and SRAD are for the curved line search +(LSDIR = 4). The first parameter is a switch (0 or 1) to invoke +this line search, an intermediate value is interpreted as +weighted combination of a straight and curved line search (the +curvature radius is decreased with increasing IRAD). A value +of unit is recommended in situations with rather smooth +responses, e.g. springback and similar problems. Also, +IRAD = 1 seems to work best with full Newton iterations. The +SRAD parameter should be equal to 0 for most cases, this +means that the search curve for a node is determined from the +search direction of nodes connected to the same elements as +that node. SRAD > 0 is interpreted as a radius of influence, +meaning that the search curve for a node is determined from +the search direction of nodes within a distance SRAD of this +node. This option was introduced as an experiment to see if +this had a smoothing and stabilizing effect. A value of 0.0 is +VARIABLE +REMARKS +currently recommended. +AWGT / SRED +The parameters AWGT and SRED are for the adaptive line +search. The intention is to improve robustness for problems +that have tendencies to oscillate or diverge, indicated by the +dnorm and enorm parameter outputs in the iterations (stdout). +A value of 0.5 is recommended for AWGT as a starting point. +With a nonzero value the motions of individual nodes are +tracked. For nodes that are oscillating (going back and forth in +space), the maximum step size for the next iteration is reduced +in proportion to the parameter AWGT, and for nodes that are +not oscillating but going nicely along a straight path, the +maximum step size for the next iteration is increased in +proportion to 1-AWGT. +In test problems, the introduction of the adaptive line search +has stabilized the implicit procedure in the sense that the +dnorm and enorm values are more monotonically decreasing +until convergence with virtually no oscillations. If a problem is +still oscillating or diverging, the user should try to increase the +AWGT parameter since this is a more restrictive approach but +probably gives a slower convergence rate. An option for nasty +problems is also to use SRED > 0 which is the initial step +reduction factor (less than 1). This means that the initial step +size is reduced by this value but the maximum step size will +increase by an amount that is determined by the success in the +iterative procedure, eventually it will reach unity. It can never +decrease. Also here, it is intended to be used with full Newton +method. +*CONTROL_IMPLICIT_SOLVER_{OPTION} +Available options include: + +DYN +SPR +Purpose: These optional cards apply to implicit calculations. The linear equation solver +performs the CPU-intensive stiffness matrix inversion . The DYN option allows setting controls specifically for the dynamic +relaxation phase. The SPR option allows setting controls specifically for the springback +phase. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LSOLVR +LPRINT +NEGEV +ORDER +DRCM +DRCPRM AUTOSPC AUTOTOL +Type +I +Default +4 +I +0 +I +2 +I +0 +I +4 +F +see +below +I +1 +F +see +below +Card 2 is optional. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCPACK MTXDMP +Type +Default +I +2 +I +VARIABLE +DESCRIPTION +LSOLVR +Linear equation solver method . +EQ.4: SMP parallel multi-frontal sparse solver (default). +EQ.5: SMP parallel multi-frontal sparse solver, double +precision +EQ.6: BCSLIB-EXT, direct, sparse, double precision +EQ.10: iterative, best of currently available iterative methods +EQ.11: iterative, Conjugate Gradient method +EQ.12: iterative, CG with Jacobi preconditioner +EQ.13: iterative, CG with Incomplete Choleski preconditioner +EQ.14: iterative, Lanczos method +EQ.15: iterative, Lanczos with Jacobi preconditioner +EQ.16: iterative, Lanczos with Incomplete Choleski precondi- +tioner +LPRINT +Linear solver print flag controls screen and message file output +. +EQ.0: no printing +EQ.1: output summary statistics on memory, cpu requirements +EQ.2: more statistics +EQ.3: even more statistics and debug checking +NOTE: during execution, use the interactive command " lprint" to toggle this print flag between 0 and 1. +NEGEV +Negative eigenvalue flag. Selects procedure when negative +eigenvalues are detected during stiffness matrix inversion . +EQ.1: stop, or retry step if auto step control is active +EQ.2: print warning message, try to continue (default) +ORDER +Ordering option +EQ.0: method set automatically by LS-DYNA +EQ.1: MMD, Multiple Minimum Degree. +EQ.2: Metis +VARIABLE +DRCM +DESCRIPTION +Drilling rotation constraint method for shells . +EQ.1: add drilling stiffness (old Version 970 method) +DRCPRM +EQ.2: same as 4 below +EQ.3: add no drilling stiffness +EQ.4: add drilling stiffness (improved method) (default) +Drilling rotation constraint parameter for shells. This parameter +scales the drilling stiffness. For the old method (DRCM = 1) the +default value of DRCPRM is 1.0 for linear analysis, 100.0 for +nonlinear implicit analysis,; and either 1.E-12 or 1.E-8 for +eigenvalue analysis depending on the shell element type. For +eigenvalue analysis, the input value for DRCPRM is ignored. For +the improved method (default, DRCM = 4), the default value of +DRCPRM is as described above for the old method except default +DRCPRM is 1.0 for nonlinear implicit analysis. +AUTOSPC +Automatic Constraint Scan flag +EQ.1: scan +the assembled stiffness matrix +for +unconstrained, unattached degrees of freedom. Generate +additional constraints as necessary to avoid negative +eigenvalues. +looking +EQ.2: do not add constraints. +AUTOTOL +AUTOSPC tolerance. The test for singularity is the ratio of the +smallest singular value and the largest singular value. If this ratio +is less than AUTOTOL, then the triple of columns are declared +singular and a constraint is generated. Default value in single +precision is 10−4 and in double precision, 10−8. +LCPACK +Matrix assembly package. +MTXDMP +EQ.2: Use v970’s LCPACK (default, only available option in +971) +EQ.3: Same as 2, but incorporates a non-symmetric linear +solver, see remark for LCPACK. +Matrix and right-hand-side dumping. LS-DYNA has the option +of dumping the globally assembled stiffness matrix and right- +hand-side vectors files in Harwell-Boeing sparse matrix format. +Such output may be useful for comparing to other linear equation +solution packages. +VARIABLE +DESCRIPTION +EQ.0: No dumping +GT.0: Dump all matrices and right-hand-side vectors every +MTXDMP time steps. Output is written as ASCII text +and the iinvolved filenames are of the following form: +K_xxxx_yyy.mtx.rb +This file contains the stiffness matrix at step xxxx, it- +eration yyy. +M_xxxx_yyy.mtx.rb +This file contains the mass matrix at step xxxx, itera- +tion. Only for eigenvalue analysis. +MW_xxxx_yyy.mtx.rb +This file contains the damping matrix at step xxxx, it- +eration. Only for simulations with damping. +K_xxxx_yyy_zzz.rhs.rb +This file contains the right hand side at step xxxx, it- +eration yyy, where yyy is the iteration at which a +stiffness matrix is formed; zzz is the cumulative itera- +tion number for the step. The values of yyy and zzz +don’t always coincide because the stiffness matrix is +not necessarily reformed every iteration. +Node_Data_xxxx_yyy +This file maps stiffness matrix to nodes and provides +nodal coordinates. +LT.0: +Like positive values of MTXDMP but dumped data +is binary. +EQ.|9999|: Simulation is terminated after dumping matrices +and right hand side prior to factorization. +Remarks: + VARIABLE +LSOLVR +REMARKS +The linear solver is used to compute the inverse of the global +stiffness matrix, which is a costly procedure both in memory and +cpu time. Direct solvers apply Gaussian elimination, while +iterative solvers successively improve “guesses” at the correct +solution. Iterative solvers require far less memory than direct +VARIABLE +REMARKS +solvers, but may suffer from convergence problems. Generally, +iterative solvers are poor for automotive applications, but can be +superior for large brick element soil models in civil engineering. +Solvers 5 and 6 promote the global matrix to double precision +before factoring to reduce numerical truncation error. Solvers 4 +and 5 are equivalent if a double precision executable is used. +Solver 6 is the direct linear equation solver from BCSLIB-EXT, +Boeing's Extreme Mathematical Library. This option should be +used whenever the factorization is too large to fit into memory. It +has extensive capabilities for out-of-core solution and can solve +larger problems than any of the other direct factorization +methods. Solver 6 also includes a sophisticated pivoting strategy +which can be superior for nearly singular matrices. +Solver 5 is the only option supported in MPP. +LPRINT +NEGEV +the +storage +timing and +Select printing of +information +(LPRINT = 1) if you are comparing performance of linear +equation solvers, or if you are running out of memory for large +models. Minimum memory requirements for in-core and out-of- +core solution are printed. This flag can also be toggled using +sense switch " lprint". For best performance, increase +available memory using “memory=“ on the command line until an IN- +CORE solution is indicated. +When using solver option 6, LPRINT = 2 and 3 will cause +increased printed output of +statistics and performance +information. +Negative eigenvalues result from underconstrained models (rigid +body modes), severely deformed elements, or non-physical +material properties. This flag allows control to be passed directly +to the automatic time step controller when negative eigenvalues +are detected. Otherwise, significant numerical roundoff error is +likely to occur during factorization, and equilibrium iterations +may fail . +ORDER +DRCPRM +LCPACK +*CONTROL_IMPLICIT_SOLVER +REMARKS +The system of linear equations is reordered to optimize the +sparsity of the factorization when using direct methods. Metis is +a ordering method from University of Minnesota which is very +effective for larger problems and for 3D solid problems, but also +very expensive. MMD is inexpensive, but may not produce an +optimum reordering, leading to higher cost during numeric +factorization. MMD is usually best for smaller problems (less +than 100,000 degrees of freedom). +Reordering cost is included in the symbolic factorization phase of +the linear solver (LSPRINT ≥ 1). For large models, if this cost +exceeds 20% of the numeric factorization cost, it may be more +efficient to select the MMD method. +Note that the values of LPRINT and ORDER also affect the +eigensolution software. That is LPRINT and ORDER from this +keyword card is applicable to eigensolution. +To avoid a singular stiffness matrix in implicit analysis of flat +shell topologies, some constraint on the drilling degree of +freedom is needed. The default method of applying this +constraint, DRCPRM = 4, adds the consistent force vector for +consistency and improved convergence as compared to the old +method, DRCPRM = 1. +In explicit analysis, an unconstrained drilling degree of freedom +is usually not a concern since a stiffness matrix is not used. +However, special situations may arise in which the user wishes to +include additional resisting rotational force in the drilling degree +of freedom for improved robustness and/or accuracy. To activate +the consistent drilling constraint in explicit analysis, use the input +variables DRCPSID and DRCPRM for *CONTROL_SHELL. +Certain features may break the symmetry of the stiffness matrix. +Unless LCPACK is set to 3 these contributions are suppressed or +symmetrized by the default symmetric linear solver. However, +when LCPACK is set to 3 a more general linear solver lifting the +symmetry requirement is used. The solver for non-symmetric +matrices is more computationally expensive. +Keywords +implemented are listed below: +for which +the non-symmetric contribution +is +*CONTACT_..._MORTAR: +VARIABLE +REMARKS +The mortar contact accounts for frictional non-symmetry +in the resulting tangent stiffness matrix, the effects on +convergence characteristics have not yet shown to be +significant. +*LOAD_SEGMENT_NONUNIFORM: +The non-symmetric contribution may be significant for the +follower load option, LCID < 0. +*LOAD_SEGMENT_SET_NONUNIFORM: +The non-symmetric contribution may be significant for the +follower load option, LCID < 0. +*MAT_FABRIC_MAP: +This stress map fabric model accounts for non-symmetry +in the material tangent modulus, representing the non- +linear Poisson effect due to complex interaction of yarns. +*SECTION_SHELL, *SECTION_SOLID: +User defined resultant elements (ELFORM = 101, 102, 103, +104, 105 with NIP=0) support the assembly and solution of +non-symmetric element matrices. +*SECTION_BEAM: +Belytschko-Schwer beam +geometric stiffness contribution is supported. +(ELFORM=2) nonsymmetric +*CONTROL_IMPLICIT_STABILIZATION_{OPTION} +Available options include: + +DYN +SPR +Purpose: This optional card applies to implicit calculations. Artificial stabilization is +required for multi-step unloading in implicit springback analysis . The DYN option allows setting controls specifically for +the dynamic relaxation phase. The SPR option allows setting controls specifically for +the springback phase. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IAS +SCALE +TSTART +TEND +Type +I +F +F +F +Default +2 +1.0 +see +below +see +below + VARIABLE +DESCRIPTION +IAS +Artificial Stabilization flag +EQ.1: active +EQ.2: inactive (default) +SCALE +Scale factor for artificial stabilization. For flexible parts with large +springback, like outer body panels, a value of 0.001 may be +required. +EQ.-n: curve ID = n gives SCALE as a function of time +TSTART +Start time. (Default: immediately upon entering implicit mode) +TEND +End time. (Default: termination time) +Remarks: +Artificial stabilization allows springback to occur over several steps. This is often +necessary to obtain convergence during equilibrium iterations on problems with large +springback deformation. Stabilization is introduced at the start time TSTART, and +slowly removed as the end time TEND is approached. Intermediate results are not +accurate representations of the fully unloaded state. The end time TEND must be +reached exactly for total springback to be predicted accurately. + VARIABLE +IAS +SCALE +REMARKS +The default for IAS depends on the analysis type in *CONTROL_- +IMPLICIT_GENERAL. + For “seamless” springback analysis, +automatic time step control and artificial stabilization are +activated by default. Otherwise, IAS is inactive by default. +This is a penalty scale factor similar to that used in contact +interfaces. If modified, it should be changed in order-of- +magnitude increments at first. Large values suppress springback +deformation until very near the termination time, making +convergence during the first few steps easy. Small values may +not stabilize the solution enough to allow equilibrium iterations +to converge. +*CONTROL_IMPLICIT_STATIC_CONDENSATION_{OPTION} +Available options include: + +BINARY +Purpose: Request static condensation of a part to build a reduced linearized model for +later computation with *ELEMENT_DIRECT_MATRIX_INPUT. + Optionally the +analysis can continue using the linearization for the current analysis. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable SC_FLAG SC_NSID SC_PSID SE_MASS SE_STIFF SE_INERT +I +0 +2 +I +0 +3 +Type +Default +I +0 + Card 2 +1 +Variable +Type +C +C +C +4 +5 +6 +7 +8 +SE_FILENAME +A80 + VARIABLE +DESCRIPTION +SC_FLAG +Static Condensation Control Flag +EQ.0: no static condensation will be performed +EQ.1: create superelement representation based on static +condensation. +EQ.2: use static condensation to build a linearized representa- +tion for a part and use that linearized representation in +the following analysis. +SC_NSID +Node set ID for nodes to be preserved in the static condensation +procedure. Required when SC_FLAG = 1. +VARIABLE +SC_PSID +SE_MASS +SE_STIFF +SE_INERT +DESCRIPTION +Part set ID for parts to be included in the static condensation +procedure. When SC_FLAG = 1, SC_PSID can be used to specify +a subset of the model with the default being the entire model. +When SC_FLAG = 2, SC_PSID is required. SC_PSID = 0 implies +that the entire model is condensed. +Name of the superelement mass matrix. If left blank it is not +generated. +Name of the superelement stiffness matrix. If left blank it is not +generated. +Name of the superelement inertia matrix, required for gravity +loading applications of the superelement. If left blank it is not +generated. +SE_FILENAME +If any of SE_MASS, SE_STIFF, or SE_INERT is blank then the +second line is required and contains the file name for the +superelement. +Remarks: +To use this feature, an implicit analysis must be requested using IMFLAG = 1 on *CON- +TROL_IMPLICIT_GENERAL, and a non-zero termination time must be specified on +*CONTROL_TERMINATION. A double precision version of LS-DYNA should be used +for best accuracy. The superelement model is written to file SE_FILENAME. +Static condenstation is the reduction of the global stiffness and mass matrices to a +specified sets of rows and columns associated with the nodes in the node set SC_NSID. +The first and second node set attribute parameters can be optionally used to restrict the +translational and rotational degrees of freedom for which modes are requested, +respectively, according to the following syntax: +Node set attribute parameters DA1 and A1: translational degree of freedom codes +Node set attribute parameters DA2 and A2: rotational degree of freedom codes +Code +0 +1 +2 +3 +4 +5 +6 +7 +Modes Computed + +X degree of freedom only +Y degree of freedom only +Z degree of freedom only +X, Y degrees of freedom only +Y, Z degrees of freedom only +X, Z degrees of freedom only +X, Y, Z degrees of freedom +Setting both node set attributes to zero is equivalent to setting both node set attributes +to 7 (X, Y, and Z for translational and rotational degrees of freedom). +If one node set attribute is nonzero (codes 1 to 7) and the other node set attribute is zero, +then the zero attribute means NO degrees of freedom are considered. For example, if +DA1 = 2 and DA2 = 0, then only the Y-translational degree of freedom modes are +calculated. +The user can create the superelement representation of the reduced model by specifying +the SE_MASS, SE_STIFF, SE_INERT and SE_FILENAME fields. This implementation +does not include SE_DAMP. The file, by default is written in the Nastran DMIG file +format and can be used as input to *ELEMENT_DIRECT_MATRIX_INPUT. The +keyword option BINARY can be used to create a binary representation for the +superelement which can be used with *ELEMENT_DIRECT_MATRIX_INPUT_BINARY +to reduce the file size. +Static Condensation is equivalent to using only constraint modes with *CONTROL_IM- +PLICIT_MODES. Static Condensation does have the ability to continue the analysis +using the linear representation for a part set. +*CONTROL_IMPLICIT_TERMINATION +Purpose: Specify termination criteria for implicit transient simulations. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DELTAU +DELTA1 +KETOL +IETOL +TETOL +NSTEP +Type +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +I +3 + VARIABLE +DELTAU +DESCRIPTION +Terminate based on relative total displacement in the Euclidean +norm. +GT.0.0: terminate when displacement in the Euclidean norm +for last time step relative to the total displacement in +the Euclidean norm is less than DELTAU. +DELTA1 +Terminate based on relative total displacement in the max norm. +GT.0.0: terminate when displacement in the max norm for last +time step relative to the total displacement in the max +norm is less than DELTAU. +KETOL +Terminate based on kinetic energy +GT.0.0: terminate when kinetic energy drops below KETOL for +NSTEP consecutive implicit time steps. +IETOL +Terminate based on internal energy +GT.0.0: terminate when internal energy drops below IETOL for +NSTEP consecutive implicit time steps. +TETOL +Terminate based on total energy +GT.0.0: terminate when total energy drops below TETOL for +NSTEP consecutive implicit time steps. +NSTEP +Number of steps used in the early termination tests for kinetic, +internal, and total energy. +*CONTROL_IMPLICIT_TERMINATION +For some implicit applications it is useful to terminate when there is no change in +displacement or low energy. This keyword provides the ability to specify such a +stopping criterias to terminate the simulation prior to ENDTIM. +*CONTROL +Purpose: Define global control parameters for material model related properties. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MAEF +Type +Default +I +0 + VARIABLE +DESCRIPTION +MAEF +Failure options: +EQ.0: all *MAT_ADD_EROSION definitions are active. +EQ.1: switch off all +*MAT_ADD_EROSION definitions +globally. This feature is useful for larger models where +removing the *MAT_ADD_EROSION cards is incon- +vient. +*CONTROL_MPP +Purpose: Set control parameters for MPP specific features. +*CONTROL_MPP_CONTACT_GROUPABLE +*CONTROL_MPP_DECOMPOSITION_ARRANGE_PARTS +*CONTROL_MPP_DECOMPOSITION_AUTOMATIC +*CONTROL_MPP_DECOMPOSITION_BAGREF +*CONTROL_MPP_DECOMPOSITION_CHECK_SPEED +*CONTROL_MPP_DECOMPOSITION_CONTACT_DISTRIBUTE +*CONTROL_MPP_DECOMPOSITION_CONTACT_ISOLATE +*CONTROL_MPP_DECOMPOSITION_DISABLE_UNREF_CURVES +*CONTROL_MPP_DECOMPOSITION_DISTRIBUTE_ALE_ELEMENTS +*CONTROL_MPP_DECOMPOSITION_DISTRIBUTE_SALE_ELEMENTS +*CONTROL_MPP_DECOMPOSITION_DISTRIBUTE_SPH_ELEMENTS +*CONTROL_MPP_DECOMPOSITION_ELCOST +*CONTROL_MPP_DECOMPOSITION_FILE +*CONTROL_MPP_DECOMPOSITION_METHOD +*CONTROL_MPP_DECOMPOSITION_NUMPROC +*CONTROL_MPP_DECOMPOSITION_OUTDECOMP +*CONTROL_MPP_DECOMPOSITION_PARTS_DISTRIBUTE +*CONTROL_MPP_DECOMPOSITION_PARTSET_DISTRIBUTE +*CONTROL_MPP_DECOMPOSITION_RCBLOG +*CONTROL_MPP_DECOMPOSITION_SCALE_CONTACT_COST +*CONTROL_MPP_DECOMPOSITION_SCALE_FACTOR_SPH +*CONTROL_MPP_DECOMPOSITION_SHOW +*CONTROL_MPP_DECOMPOSITION_TRANSFORMATION +*CONTROL_MPP_IO_LSTC_REDUCE +*CONTROL_MPP_IO_NOBEAMOUT +*CONTROL_MPP_IO_NOD3DUMP +*CONTROL_MPP_IO_NODUMP +*CONTROL_MPP_IO_NOFAIL +*CONTROL_MPP_IO_NOFULL +*CONTROL_MPP_IO_SWAPBYTES +*CONTROL_MPP_MATERIAL_MODEL_DRIVER +*CONTROL_MPP_PFILE +*CONTROL_MPP_CONTACT_GROUPABLE +Purpose: Allow for global specification that the GROUPABLE algorithm should be +enabled/disabled for contacts when running MPP. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +GRP +Type +I +Default +none + VARIABLE +GRP +DESCRIPTION +The sum of these available options (in any combination that +makes sense): +1: Turn on GROUPABLE for all non-tied contacts +2: Turn on GROUPABLE for all tied contacts +4: Turn off GROUPABLE for all non-tied contacts +8: Turn off GROUPABLE for all tied contacts +Remarks: +The GROUPABLE algorithm is an alternate MPP communication algorithm for SIN- +GLE_SURFACE, NODE_TO_SURFACE, and SURFACE_TO_SURFACE contacts. This +algorithm does not support all contact options, including SOFT = 2, as of yet, and is still +under development. It can be significantly faster and scale better than the normal +algorithm when there are more than two or three applicable contact types defined in the +model. Its intent is to speed up the contact processing but not to change the behavior of +the contact. + This keyword will override any setting of the GRPABLE parameter on the *CON- +TACT_…_MPP card, and is intended as a way to quickly experiment with this feature. +The equivalent pfile option is “contact { groupable GRP }” where GRP is an integer as +described above. +*CONTROL_MPP_DECOMPOSITION_ARRANGE_PARTS_OPTION +Purpose: Allow users to distribute certain part(s) to all processors or to isolate certain +part(s) in a single processor. This keyword supports multiple entries. Each entry is be +processed as a separate region for decomposition. +When this keyword is part of an included file and the LOCAL option is given, the +decomposition will be done in the coordinate system of the included file, which may be +different from the global system, if the file is included using the *INCLUDE_TRANS- +FORM keyword. + Card 1 +Variable +1 +ID +2 +3 +4 +5 +6 +7 +8 +TYPE +NPROC +FRSTP +Type +I +I +I +I +Default +none +none +None +None + VARIABLE +DESCRIPTION +ID +TYPE +Part ID/Part set ID +EQ.0: Part ID to be distributed to all processors +EQ.1: Part Set ID to be distributed to all processors +EQ.10: Part ID to be lumped into one processor +EQ.11: Part Set ID to be lumped into one processor. +NPROC +Used only for TYPE equal to 0 or 1. Evenly distributed Part +ID/Part set ID to NPROC of processors. +FRSTP +Used only for TYPE equal to 0 or 1. Starting MPP rank ID. +Remarks: +There is no equivalent option under pfile. +*CONTROL_MPP_DECOMPOSITION_AUTOMATIC +Purpose: Instructs the program to apply a simple heuristic to try to determine the +proper decomposition for the simulation. +There are no input parameters. The existence of this keyword triggers the automated +decomposition. This option should not be used if there is more than one occurrence of +any of the following options in the model: +*INITIAL_VELOCITY +*CHANGE_VELOCITY +*BOUNDARY_PRESCRIBED_MOTION +And the following control card must not be used: +*CONTROL_MPP_DECOMPOSITION_TRANSFORMATION +For the general case, it is recommended that you specify the proper decomposition +using +*CONTROL_MPP_DECOMPOSITION_TRANSFORMATION +instead. +the command +*CONTROL_MPP_DECOMPOSITION_BAGREF +Purpose: With this card LS-DYNA performs decomposition according to the airbag’s +reference geometry, rather than the folded geometry. +Other than BAGID values this card takes no input parameters. The initial geometry +may lead to a poor decomposition once the bag is deployed. This option will improve +load balancing for the fully deployed geometry. +Optional card(s) for selected reference geometry ID + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +BAGID1 +BAGID2 +BAGID3 +BAGID4 +BAGID5 +BAGID6 +BAGID7 +BAGID8 +Type +I +I +I +I +I +I +I +I +Default +none +none +none +none +none +none +none +none + VARIABLE +BAGIDi +DESCRIPTION +ID defined +*AIRBAG_SHELL_REFERENCE_GEOMETRY_ID +in *AIRBAG_REFERENCE_GEOMETRY_ID or +Bags specified in the optional cards will be decomposed based on the reference +geometry. If there is no card given, all bags will be decomposed by their reference +geometry. +Remarks: +Command in partition file (pfile): BAGREF. The option for selecting particular airbags is +only available when using keyword input. +*CONTROL_MPP_DECOMPOSITION_CHECK_SPEED +Purpose: Modifies the decomposition depending on the relative speed of the processors +involved. +There are no input parameters. Use of this keyword activates a short floating point +timing routine to be executed on each processor. The information gathered is used +during the decomposition, with faster processors being given a relatively larger portion +of the problem. This option is not recommended on homogeneous systems. +*CONTROL_MPP_DECOMPOSITION_CONTACT_DISTRIBUTE_OPTION +Purpose: Ensures that the indicated contact interfaces are distributed across all +processors, which can lead to better load balance for large contact interfaces. If this +appears in an included file and the LOCAL option is given, the decomposition will be +done in the coordinate system of the included file, which may be different from the +global system if the file is included via *INCLUDE_TRANSFORM. + Card 1 +1 +Variable +ID1 +2 +ID2 +3 +ID3 +4 +ID4 +5 +ID5 +6 +7 +8 +Type +I +I +I +I +I +Default +none +none +none +none +none +DESCRIPTION +First contact interface ID to distribute. If no contact ID's are +specified, the number given here corresponds to the order of the +interfaces as they appear in the input, with the first being 1. +Remaining interfaces ID's to distribute. + VARIABLE +ID1 +ID2, ID3, +ID4, ID5 +Remarks: +Up to 5 contact interface ID's can be specified. The decomposition is modified as +follows: First, all the elements involved in the first contact interface are decomposed +across all the processors. Then all the elements involved in the second contact interface +(excluding any already assigned to processors) are distributed, and so on. After all the +contact interfaces given are processed, the rest of the input is decomposed in the normal +manner. This will result in each processor having possibly several disjoint portions of +the input assigned to it, which will increase communications somewhat. However, this +can be offset by improved load balance in the contact. It is generally recommended that +at most one or two interfaces be specified, and then only if they are of substantial size +relative to the whole problem. +*CONTROL_MPP_DECOMPOSITION_CONTACT_ISOLATE +Purpose: Ensures that the indicated contact interfaces are isolated on a single processor, +which can lead to decreased communication. + Card 1 +1 +Variable +ID1 +2 +ID2 +3 +ID3 +4 +ID4 +5 +ID5 +6 +7 +8 +Type +I +I +I +I +I +Default +none +none +none +none +none +DESCRIPTION +First contact interface ID to isolate. If no contact ID's are +specified, the number given here corresponds to the order of the +interfaces as they appear in the input, with the first being 1. +Remaining interfaces ID's to isolate. + VARIABLE +ID1 +ID2, ID3, +ID4, ID5 +Remarks: +Up to 5 contact interfaces can be specified. The decomposition is modified as follows: +First, all the elements involved in the first contact interface ID are assigned to the first +processor. Then all the elements involved in the second contact interface ID (excluding +any already assigned to processors) are assigned to the next processor, and so on. After +all the contact interfaces given are processed, the rest of the input is decomposed in the +normal manner. This will result in each of the interfaces being processed on a single +processor. For small contact interfaces this can result in better parallelism and +decreased communication. +Purpose: Disable unreferenced time dependent load curves for the following keyword. +*BOUNDARY_PRESCRIBED_MOTION_NODE +*LOAD_NODE +*LOAD_SHELL_ELEMENT +*LOAD_THERMAL_VARIABLE_NODE +The details of this operation are reported in each processor’s scratch “scr####” file. +This will skip the curve evaluation on each cycle, and improve the parallel efficiency. +Remarks: +Command in partition file (pfile): DUNREFLC. +*CONTROL_MPP_DECOMPOSITION_DISTRIBUTE_ALE_ELEMENTS +Purpose: Ensures ALE elements are evenly distributed to all processors +There are no input parameters and the card below is optional. ALE elements usually +have higher computational cost than other type of elements and it is better to distribute +them to all CPU for better load balance. The existence of this keyword causes +DYNA/MPP to extract ALE parts from input and then evenly distributed to all +processors. +The card is optional + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable OVERLAP +Type +I +Default +none + VARIABLE +OVERLAP +DESCRIPTION +For FSI models where structures are inside ALE meshes , decompose +structure and ALE domains together instead of first the structure +and then ALE . +Set type: +EQ.0: Off +EQ.1: On +Remarks: +1. Command in partition file (pfile): ALEDIST. +2. Most of the processors will have to deal with MPP subdomains from the +structure and ALE meshes: a portion of the ALE computational domain and a +portion of the structure meshes. The default decomposition (first divide the +structures, then ALE) does not always overlap these subdomains. The more +they overlap, the lesser the MPP communications in the coupling cost. Cutting +the ALE and structure meshes together allows their MPP subdomains to be as +inclusive as possible. +*CONTROL_MPP_DECOMPOSITION_DISTRIBUTE_SPH_ELEMENTS +Purpose: Ensures SPH elements are evenly distributed to all processors +There are no input parameters. SPH elements usually have higher computational cost +than other type of elements and it is better to distribute them to all CPU for better load +balance. The existence of this keyword causes DYNA/MPP to extract SPH parts from +input and then evenly distributed to all processors. +Remarks: +Command in partition file (pfile): SPHDIST. +*CONTROL_MPP_DECOMPOSITION_ELCOST +Purpose: Instructs the program to use a hardware specific element cost weighting for +the decomposition + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ITYPE +Type +I +Default +none + VARIABLE +DESCRIPTION +ITYPE +Hardware specific cost profile. +EQ.1: Fujitsu PrimePower +EQ.2: Intel IA 64, AMD Opteron +EQ.3: Intel Xeon 64 +EQ.4: General profile +Remarks: +Command in partition file (pfile): elcost itype. +*CONTROL_MPP_DECOMPOSITION_FILE +Purpose: Allow for pre-decomposition and a subsequent run or runs without having to +do the decomposition. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +Default +NAME +A80 +none + VARIABLE +DESCRIPTION +NAME +Name of a file containing (or to contain) a decomposition record. +Remarks: +If the indicated file does not exist, it is created with a copy of the decomposition +information from this run. If the file exists, it is read and the decomposition steps can +be skipped. The original run that created the file must be for a number of processors +that is a multiple of the number of processors currently being used. Thus, a problem +can be decomposed once for, say, 48 processors. Subsequent runs are then possible on +any number that divides 48: 1, 2, 3, 4, 6, etc. Since the decomposition phase generally +requires more memory than execution, this allows large models to be decomposed on +one system and run on another (provided the systems have compatible binary formats). +The file extension “.pre” is added automatically. +*CONTROL_MPP_DECOMPOSITION_METHOD +Purpose: Specify the decomposition method to use. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +Default + VARIABLE +NAME +NAME +A80 +RCB +DESCRIPTION +Name of the decomposition method to use. There are currently +two options: +EQ.“RCB”: +recursive coordinate bisection +EQ.“GREEDY”: a simple heuristic method +In almost all cases the RCB method is superior and should be +used. +*CONTROL_MPP_DECOMPOSITION_NUMPROC +Purpose: Specify the number of processors for decomposition. +2 +3 +4 +5 +6 +7 +8 + Card 1 +Variable +Type +1 +N +I +Default +none + VARIABLE +DESCRIPTION +N +Number of processors for decomposition. +Remarks: +This is used in conjunction with the CONTROL_MPP_DECOMPOSITION_FILE +command to allow for later runs on different numbers of processors. By default, the +decomposition is performed for the number of processors currently being used. +However, a different value can be specified here. If N > 1 and only one processor is +currently being used, the decomposition is done and then the program terminates. If N +is not a multiple of the current number of processors, then it is ignored the execution +proceeds with the current number of processors. Otherwise, the decomposition is +performed for N processors, and the execution continues using the current number of +processors. +*CONTROL_MPP_DECOMPOSITION_OUTDECOMP +Purpose: Instructs the program to output element's ownership data to file for post- +processor to show state data from different processors + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TYPE +Type +I +Default +none + VARIABLE +DESCRIPTION +ITYPE +Sets the format for the output file. +EQ.1: database in LS-PrePost format: +decomp_parts.lsprepost. +EQ.2: database in animator format: +decomp_parts.ses +Remarks: +Command in partition file (pfile): OUTDECOMP ITYPE. +When ITYPE is set to 1, the elements assigned to any particular core can be viewed and +animated by LS-PrePost by (1) reading the d3plot data, and then (2) selecting +Models > Views > MPP > Load > decomp_parts.lsprepost. +*CONTROL_MPP_DECOMPOSITION_PARTS_DISTRIBUTE_OPTION +Purpose: Distribute the parts given in this option to all processors before the +decomposition for the rest of the model is performed. If this appears in an included file +and the LOCAL option is given, the decomposition will be done in the coordinate +system of the included file, which may be different from the global system if the file is +included via *INCLUDE_TRANSFORM. + Card 1 +1 +Variable +ID1 +2 +ID2 +3 +ID3 +4 +ID4 +5 +ID5 +6 +ID6 +7 +ID7 +8 +ID8 +Type +I +I +I +I +I +I +I +I +Default +none +none +none +none +none +none +none +none + VARIABLE +ID1, ID2, +ID3, … +DESCRIPTION +For each ID: +GT.0: ID is a part number. +LT.0: –ID is a part set number. +All parts defined in this card will be treated as a single region to +be decomposed. +Remarks: +Up to 16 parts/part sets can be specified. The decomposition is modified as follows: +the elements involved in the given parts are put into a separate domain from rest of the +model and then distributed to all processors to balance their computational cost. Then +the remainder of the model will be distributed in the usual way. +This is equivalent to the pfile command (for example, if ID1-ID3 are part ids and ID4- +ID6 are partset ids): + decomp { region { parts ID1 ID2 ID3 or partsets ID4 ID5 ID6 } } +(the partset ids are positive when used in the pfile). +*CONTROL_MPP_DECOMPOSITION_PARTSET_DISTRIBUTE_OPTION +Purpose: Distribute the part sets given in this option to all processors before the +decomposition for the remainder of the model is performed. If this appears in an +included file and the LOCAL option is given, the decomposition will be done in the +coordinate system of the included file, which may be different from the global system if +the file is included via *INCLUDE_TRANSFORM. + Card 1 +1 +Variable +ID1 +2 +ID2 +3 +ID3 +4 +ID4 +5 +ID5 +6 +ID6 +7 +ID7 +8 +ID8 +Type +I +I +I +I +I +I +I +I +Default +none +none +none +none +none +none +none +none +DESCRIPTION +Partset ID to be distributed.. All parts in ID1 will be shared +across all processors. Then all parts in ID2 will be distributed, +and so on.. + VARIABLE +ID1, ID2, +ID3, … +Remarks: +Any number of part sets can be specified. Each part set is distributed across all +processors, in the order given. The order may be significant, in particular, if a part ID is +in more than one set. Distribution of these parts is done before any decomposition +specifications given in the pfile. +*CONTROL_MPP_DECOMPOSITION_RCBLOG +Purpose: Causes the program to record decomposition information in the indicated file, +for use in subsequent analyses. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +FILENAME +A80 +none +DESCRIPTION +Name of output file where decomposition history will be +recorded. This file can be used as the pfile for later analyses. +Variable +Type +Default + VARIABLE +FILENAME +Remarks: +Command in parallel option file (pfile): rcblog filename. +*CONTROL_MPP_DECOMPOSITION_SCALE_CONTACT_COST +Purpose: Instructs the program to apply a scale factor to the list of contacts to change +the partition weight for the decomposition. + Card 1 +Variable +1 +SF +2 +ID1 +3 +ID2 +4 +ID3 +5 +ID4 +6 +ID5 +7 +ID6 +8 +ID7 +Type +F +I +I +I +I +I +I +I +Default +none +none +none +none +none +none +none +none + VARIABLE +DESCRIPTION +SF +Scale factor for the contact segments listed in the interface ID. +ID1, ID2, … +interfaces ID's to be considered for scaling. Include second card if +necessary. +Remarks: +Up to 15 contact interfaces ID can be specified. The decomposition is modified by +applying this scale factor to the default computational cost of elements for the given +contact interface ID. +Command in partition file (pfile): CTCOST ID1, ID2, …, SF. +*CONTROL_MPP_DECOMPOSITION_SCALE_FACTOR_SPH +Purpose: Instructs the program to apply a scale factor to SPH elements to change the +partition weight for the decomposition. +2 +3 +4 +5 +6 +7 +8 + Card 1 +Variable +1 +SF +Type +F +Default +none + VARIABLE +DESCRIPTION +SF +Scale factor +Remarks: +Command in partition file (pfile): SPHSF SF. +*CONTROL_MPP_DECOMPOSITION_SHOW +Purpose: The keyword writes the final decomposition to the d3plot database. There are +no input parameters. +This keyword causes MPP LS-DYNA to terminate immediately after the decomposition +phase without performing an analysis. The resulting d3plot database is designed to +allow visualization of the decomposition by making each part correspond to the group +of solids, shells, beams, thick shells, or SPH particles assigned to a particular processor. +For example, in a model that includes various element types including solids, part 1 +corresponds to the solid elements assigned to processor 1, part 2 corresponds to the +solid elements assigned to processor 2, and so on. +This command can be used in conjunction with the *CONTROL_MPP_DECOMPOSI- +TION_NUMPROC command to run on one processor and produce a d3plot file to +visualize the resulting decomposition for the number of processors specified in *CON- +TROL_MPP_DECOMPOSITION_NUMPROC. +*CONTROL_MPP_DECOMPOSITION_TRANSFORMATION +Purpose: Specifies transformations to apply to modify the decomposition. +There are 10 different kinds of decomposition transformations available. For a detailed +description of each, see Appendix O the LS-DYNA MPP user guide. +The data cards for this keyword consist of transformation operations. Each operation, +depending on its type, involves either one or two additional cards. The input deck may +include an arbitrary number of transformations with the next keyword, “*,” card +terminating this input. +Transformation Card 1. For each transformation this card is required. + Card 1 +1 +Variable +TYPE +2 +V1 +Type +A10 +F +3 +V2 +F +4 +V3 +F +5 +V4 +F +6 +V5 +F +7 +V6 +F +8 +Default +none +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Transformation Card 2. Additional card for TYPE set to one of VEC3, C2R, S2R, MAT. +4 +5 +6 +7 +8 + Card 2 +Variable +1 +V7 +Type +F +2 +V8 +F +3 +V9 +F +Default +0.0 +0.0 +0.0 + VARIABLE +TYPE +DESCRIPTION +Which transformation to apply. The allowed values are RX, RY, +RZ, SX, SY, SZ, VEC3, C2R, S2R, and MAT. +VARIABLE +DESCRIPTION +V1 - V9 +For type set to either RX, RY, RZ, SX, SY, or SZ: +The parameter V1 gives either the angle of rotation (RX, +RY, RZ) or the magnitude for the scaling (SX, SY, SZ). The +remaining parameters are ignored. +For type set to either VEC3, C2R, S2R, or MAT: +All parameters are used. See the appendix for the “pfile.” +*CONTROL_MPP_IO_LSTC_REDUCE +Purpose: Use LSTC's own reduce routine to get consistent summation of floating point +data among processors. There are no input parameters. +Remarks: +Command in partition file (pfile): lstc_reduce. +*CONTROL_MPP_IO_NOBEAMOUT +Purpose: Suppress beam, shell, and solid element failure messages in the d3hsp and +message files. There are no parameters for this keyword. +Remarks: +Command in parallel option file (pfile): nobeamout. +*CONTROL_MPP_IO_NOD3DUMP +Purpose: Suppresses the output of all dump files. +There are no input parameters. The existence of this keyword causes the d3dump and +runrsf file output routines to be skipped. +*CONTROL_MPP_IO_NODUMP +Purpose: Suppresses the output of all dump files and full deck restart files. +There are no input parameters. The existence of this keyword causes the d3dump and +runrsf file output routines to be skipped. It also suppresses output of the full deck +restart file d3full. +*CONTROL +Purpose: Turn off failed element checking in MPP contact. If you know that no +elements will fail, or that any such failure will not impact any of the contact +calculations, turning on this option can increase the efficiency of the contact routines. +There are no input parameters. +*CONTROL_MPP_IO_NOFULL +Purpose: Suppresses the output of the full deck restart files. +There are no input parameters. The existence of this keyword suppresses the output of +the full deck restart file d3full. +*CONTROL_MPP_IO_SWAPBYTES +Purpose: Swap bytes on some of the output files. +There are no input parameters. The existence of this keyword causes the d3plot file and +the “interface component analysis” file to be output with bytes swapped. This is to +allow further processing of data on a different machine that has big endian vs. little +endian incompatibilities compared to the system on which the analysis is running. +*CONTROL_MPP_MATERIAL_MODEL_DRIVER +Purpose: Enable this feature in MPP mode. To allow MPP reader to pass the input +phase even without any nodes and elements but using only one processor. +*CONTROL_MPP_PFILE +Purpose: Provide keyword support for the MPP “p=” pfile options +All lines of input up to the next keyword card will be copied to a temporary file which +is effectively pre-pended to the “p=” file given on the command line (even if no such +file is given). This allows all options available via the “p=” file to be specified in the +keyword input. The only restriction is that pfile directives in the “directory” section are +not available, as those must be processed before the keyword input file is read. See the +“LS-DYNA MPP User Guide” in the appendix for details of the available pfile +commands and their syntax. +*CONTROL_NONLOCAL +Purpose: Allocate additional memory for *MAT_NONLOCAL option. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +MEM +Type +I +Default +none + VARIABLE +MEM +DESCRIPTION +Percentage increase of memory allocated for *MAT_NONLOCAL +option over that required initially. This is for additional storage +that may be required due to geometry changes as the calculation +proceeds. Generally, a value of 10 should be sufficient. +*CONTROL +Purpose: Set miscellaneous output parameters. This keyword does not control the +information, such as the stress and strain tensors, which is written into the binary +databases. For the latter, see the keyword *DATABASE_EXTENT_BINARY. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NPOPT +NEECHO NREFUP +IACCOP +OPIFS +IPNINT +IKEDIT +IFLUSH +Type +Default +I +0 +I +0 +I +0 +I +0 +F +0. +I +0 +I +I +100 +5000 +Remaining cards are optional. +Optional Card 2 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IPRTF +IERODE +TET10S8 MSGMAX +IPCURV +GMDT +IP1DBLT +EOCS +Type +Default +I +0 +I +0 +I +2 +I +50 +I +0 +F +0. +I +0 +I +0 +Optional Card 3 + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TOLEV +NEWLEG +FRFREQ MINFO +SOLSIG MSGFLG CDETOL +Type +Default +I +2 +I +0 +I +1 +I +0 +I +0 +I +0 +F +10.0 +*CONTROL_OUTPUT + Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable PHSCHNG DEMDEN +Type +Default +I +0 +I +0 + VARIABLE +DESCRIPTION +NPOPT +Print suppression during input phase flag for the “d3hsp” file: +EQ.0: no suppression, +EQ.1: nodal coordinates, element connectivities, rigid wall +definitions, nodal SPCs, initial velocities, initial strains, +adaptive constraints, and SPR2/SPR3 constraints are not +printed. +NEECHO +Print suppression during input phase flag for “echo” file: +EQ.0: all data printed, +EQ.1: nodal printing is suppressed, +EQ.2: element printing is suppressed, +EQ.3: both node and element printing is suppressed. +NREFUP +Flag to update reference node coordinates for beam formulations +1, 2, and 11. This option requires that each reference node is +unique to the beam: +EQ.0: Do not update reference node. +EQ.1: Update reference node: This update +is required for +proper visualization of the beam cross-section orienta- +tion in LS-PrePost beyond the initial (𝑡 = 0) plot state. +NREFUP does not affect the internal updating of the +beam cross-section orientation in LS-DYNA. +VARIABLE +IACCOP +OPIFS +IPNINT +IKEDIT +IFLUSH +DESCRIPTION +Flag to average or filter nodal accelerations output to file +“nodout” and the time history database “d3thdt”: +EQ.0: no average (default), +EQ.1: averaged between output intervals, +EQ.2: accelerations for each time step are stored internally and +then filtered over each output interval using a filter from +General Motors [Sala, Neal, and Wang, 2004] based on a +low-pass Butterworth frequency filter. See also [Neal, +Lin, and Wang, 2004]. +in *CONTROL_- +TIMESTEP must be set to a negative value when IAC- +COP = 2 so that the maximum possible number of time +steps for an output interval is known and adequate +memory can be allocated. See Figure 12.15. + DT2MS +Output time interval for interface file written per *INTERFACE_- +COMPONENT_option. +Flag controlling output of initial time step sizes for elements to +“d3hsp”: +EQ.0: 100 elements with the smallest time step sizes are +printed. +EQ.1: Time step sizes for all elements are printed. +GT.1: IPNINT elements with the smallest time step sizes are +printed. +Problem status report interval steps to the “d3hsp” file. This flag +is ignored if the “glstat” file is written, see *DATABASE_GL- +STAT. +Number of time steps interval for flushing I/O buffers. The +default value is 5000. If the I/O buffers are not emptied and an +abnormal termination occurs, the output files can be incomplete. +The I/O buffers for restart files are emptied automatically +whenever a restart file is written so these files are not affected by +this option. +IPRTF +*CONTROL_OUTPUT +DESCRIPTION +Default print flag for “rbdout” and “matsum” files. This flag +defines the default value for the print flag which can be defined +in the part definition section, see *PART. This option is meant to +reduce the file sizes by eliminating data which is not of interest. +EQ.0: write part data into both matsum and rbdout +EQ.1: write data into rbdout file only +EQ.2: write data into matsum file only +EQ.3: do not write data into rbdout and matsum +IERODE +Output eroded internal and kinetic energy into the “matsum” file. +Also, output to the “matsum” file under the heading of part ID 0 +is the kinetic energy from nonstructural mass, lumped mass +elements and lumped inertia elements. +TET10S8 +EQ.0: do not output extra data +EQ.1: output the eroded internal and kinetic energy +Output ten connectivity nodes for the 10-node solid tetrahedral +and the eight connectivity nodes for the 8-node shell into +“d3plot” database. The current default is set to 2 since this +change in the database may make the data unreadable for many +popular post-processors and older versions of LS-PrePost. The +default will change to 1 later. +EQ.1: write the full node connectivity into the “d3plot” +database +EQ.2: write only the corner nodes of the elements into the +“d3plot” database +MSGMAX +Maximum number of each error/warning message +GT.0: number of messages to screen output, all messages +written to d3hsp/messag +LE.0: number +of messages +to +screen +output +and +d3hsp/messag +EQ.0: default, 50 +IPCURV +Flag to output digitized curve data to “messag” and d3hsp files. +EQ.0: off +EQ.1: on +VARIABLE +GMDT +DESCRIPTION +Output interval for recorded motions from *INTERFACE_SSI_- +AUX +IP1DBLT +Output information of 1D (bar-type) seatbelt created for 2D (shell- +type) seatbelt to sbtout. +EQ.0: the analysis results of internally created 1D seatbelts are +extracted and processed to yield the 2D belt information. +The 2D belt information is stored in sbtout, +EQ.1: the analysis results of internally created 1D retractors +and slip rings are stored in sbtout. Belt load can be +yielded by *DATABASE_CROSS_SECTION. +EOCS +Elout Coordinate System: controls the coordinate system to be +used when writing out shell data to the “elout” file: +EQ.0: default +EQ.1: local element coordinate system +EQ.2: global coordinate system +TOLEV +NEWLEG +FRFREQ +Timing Output Levels: controls the # of levels output in the +timing summary at termination. The default is 2. +New Legends: controls the format of the LEGEND section of +various ASCII output files. +EQ.0: use the normal format +EQ.1: use the optional format with extra fields. +Output frequency for failed element report, in cycles. The default +is to report the summary every cycle on which an element fails. +If > 1, the summary will be reported every FRFREQ cycles +whether an element fails that cycle or not, provided some element +has failed since the last summary report. Individual element +failure is still reported as it occurs. +MINFO +Output penetration information for mortar contact after each +implicit step, not applicable in explicit analysis. See remarks on +mortar contact on *CONTACT card. +EQ.0: No information +EQ.1: Penetrations reported for each contact interface. +SOLSIG +MSGFLG +CDETOL +*CONTROL_OUTPUT +DESCRIPTION +Flag to extrapolate stresses and other history variables for multi- +integration point solids from integration points to nodes. These +extrapolated nodal values replace the integration point values +normally stored in d3plot. When a nonzero SOLSIG is invoked, +NINTSLD in *DATABASE_EXTENT_BINARY should be set to 8 +as any other value of NINTSLD will result in only one value +being reported for each element. Supported solid formulations +are: -1, -2, 2, 3, 4, 18, 16, 17, and 23. +NOTE: Do not use "Setting - Extrapolate" in LS- +PrePost when this field, SOLSIG, is nonzero. +EQ.0: No extrapolation. +EQ.1: Extrapolate the stress for linear materials only. +EQ.2: Extrapolate the stress if plastic strain is zero. +EQ.3: Extrapolate the stress always. +EQ.4: Extrapolate all history variables. +Flag for writing detailed error/warning messages to d3msg. +MSGFLG has no affect on +length +error/warning messages; such messages are written to messag or +mes****. NOTE: Most errors/warnings offer only standard length +messages. Only a few also offer optional, detailed messages. + output of standard +EQ.0: Do not write detailed messages to d3msg. +EQ.1: Write detailed messages to d3msg at the conclusion of +the run. Each detailed message is written only once even +in cases where the associated error or warning occurs +multiple times. +for output of +*DEFINE_CURVE discretization +Tolerance +warnings. After each curve is discretized, the resulting curve is +evaluated at each of the original definition points, and the values +compared. A warning will be issued for any curve where this +comparison results in an error of more than CDETOL/100 × 𝑀, +where the curve specific value 𝑀 is computed as the median of +the absolute values of the non-zero curve values. +VARIABLE +PHSCHNG +DESCRIPTION +Message to messag file when materials 216, 217, and 218 change +phase.. +EQ.0: (default) no message. +EQ.1: The time and element ID are written. +DEMDEN +Output DEM density data to d3plot database.. +EQ.0: (default) no output. +EQ.1: output data. +*CONTROL_PARALLEL +Purpose: Control parallel processing usage by defining the number of processors and +invoking the optional consistency of the global vector assembly. This command applies +only to shared memory parallel (SMP) LS-DYNA. It does not apply to distributed +memory parallel (MPP) LS-DYNA. +Card +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NCPU +NUMRHS +CONST +PARA +Type +Default +I +1 +Remarks + VARIABLE +NCPU +I +0 +1 +I +2 +2 +I +0 +3 +DESCRIPTION +Number of cpus used. +(This parameter is disabled in 971 R5 and later versions. Set +number of cpus using “ncpu=” on the execution line — see +Execution Syntax section of Getting Started — or on the +*KEYWORD line of the input.) +NUMRHS +Number of right-hand sides allocated in memory: +EQ.0: same as NCPU, always recommended, +EQ.1: allocate only one. +CONST +Consistency flag. (Including “ncpu=n” on the execution line or +on the *KEYWORD line of input overrides CONST. The algebraic +sign of n determines the consistency setting.) +EQ.1 or n < 0: +EQ.2 or n > 0: +on (recommended) +off, for a faster solution (default). +VARIABLE +PARA +DESCRIPTION +Flag for parallel force assembly if CONST=1. (Including “para=” +on the execution line overrides PARA.) +EQ.0: off +EQ.1: on +EQ.2: on +Remarks: +1. +It is recommended to always set NUMRHS = NCPU since great improvements +in the parallel performance are obtained since the force assembly is then done +in parallel. Setting NUMRHS to one reduces storage by one right hand side +vector for each additional processor after the first. If the consistency flag is +active, i.e., CONST = 1, NUMRHS defaults to unity. +2. For any given problem with the consistency option off, i.e., CONST = 2, slight +differences in results are seen when running the same job multiple times with +the same number of processors and also when varying the number of proces- +sors. Comparisons of nodal accelerations often show wide discrepancies; how- +ever, it is worth noting that the results of accelerometers often show +insignificant variations due to the smoothing effect of the accelerometers which +are generally attached to nodal rigid bodies. +The accuracy issues are not new and are inherent in numerical simulations of +automotive crash and impact problems where structural bifurcations under +compressive loads are common. This problem can be easily demonstrated by +using a perfectly square thin-walled tubular beam of uniform cross section +under a compressive load. Typically, every run on one processor that includes +a minor input change (i.e., element or hourglass formulation) will produces +dramatically different results in terms of the final shape, and, likewise, if the +same problem is again run on a different brand of computer. If the same prob- +lem is run on multiple processors the results can vary dramatically from run to +run WITH NO INPUT CHANGE. The problem here is due to the randomness +of numerical round-off which acts as a trigger in a “perfect” beam. +Since summations with (CONST=2) occur in a different order from run to run, +the round-off is also random. The consistency flag, CONST=1, provides for +identical results (or nearly so) whether one, two, or more processors are used +while running in the shared memory parallel (SMP) mode. This is done by +requiring that all contributions to global vectors be summed in a precise order +independently of the number of processors used. When checking for consistent +results, nodal displacements or element stresses should be compared. The +NODOUT and ELOUT files should be digit to digit identical. However, the +GLSTAT, SECFORC, and many of the other ASCII files will not be identical +since the quantities in these files are summed in parallel for efficiency reasons +and the ordering of summation operations are not enforced. The biggest draw- +back of this option is the CPU cost penalty which is at least 15 percent if PA- +RA=0 and is much less if PARA=1 and 2 or more processors are used. Unless +the PARA flag is on (for non-vector processors), parallel scaling is adversely +affected. The consistency flag does not apply to MPP parallel. +3. PARA set to 1 or 2 will cause the force assembly for the consistency option to be +performed in parallel for the SMP version, so better scaling will be obtained. +However, PARA = 1 will increase memory usage while PARA = 2 will not. +This flag does not apply to the MPP version. If PARA = CONST = 0 and +NUMRHS = NCPU the force assembly by default is done in parallel, but with- +out consistency. The value of the flag may also be given by including “pa- +ra=” on the execution line, and the value given in this manner will +override the value of PARA in *CONTROL_PARALLEL. +*CONTROL +Purpose: Set parameters for pore water pressure calculations. +This control card is intended for soil analysis. However, other materials containing +pore fluid could be treated by the same methods. The pore pressure capabilities +invoked by this card are available in SMP and MPP versions of LS-DYNA, but are not +available for implicit solutions. Furthermore, pore pressure capabilities are limited to a +subset of 3-D solid Lagrangian element formulations, including solid formulations 1, 2, +4, 10, and 15. +LS-DYNA uses Terzaghi’s Effective Stress to model materials with pore pressure. The +pore fluid and soil skeleton are assumed to occupy the same volume and to carry loads +in parallel. Thus, the total stress in an element is the sum of the “effective stress” in the +soil skeleton, plus the hydrostatic stress in the pore fluid. LS-DYNA calculates the +“effective stress” with standard material models. The pore fluid treatment, then, is +independent of material model. The pore pressure is calculated at nodes, and +interpolated onto the elements. The pore fluid’s hydrostatic stress is equal to the +negative of the element pore pressure. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ATYPE +(blank) WTABLE +PF_RHO +GRAV +PF_BULK OUTPUT +TMF +Type +Default +I +0 +F +F +F +F +F +0.0 +0.0 +(none) +(none) +(none) + Card 2 +1 +2 +3 +4 +5 +6 +I +0 +7 +F +1.0 +8 +Variable +TARG +FMIN +FMAX +FTIED +CONV +CONMAX +ETERM +THERM +Type +F +F +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +1.E-4 +1.E20 +0.0 +0.0 +*CONTROL_PORE_FLUID + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ETFLAG +Type +Default +I +0 + VARIABLE +DESCRIPTION +ATYPE +Analysis type for pore water pressure calculations: +EQ.0: No pore water pressure calculation. +EQ.1: Undrained analysis, +EQ.2: Drained analysis, +EQ.3: Time dependent consolidation (coupled), +EQ.4: Consolidate to steady state (uncoupled), +EQ.5: Drained in dynamic relaxation, undrained in transient, +EQ.6: As 4 but do not check convergence, continue to end time. +WTABLE +Default z-coordinate of water table (where pore pressure is zero). +PF_RHO +Default density for pore water. +GRAV +Gravitational acceleration used to calculate hydrostatic pore +water pressure. +PF_BULK +Default bulk modulus of pore fluid (stress units). +OUTPUT +Output flag controlling stresses to D3PLOT and D3THDT binary +files: +EQ.0: total stresses are output +EQ.1: effective stresses are output, see notes +VARIABLE +DESCRIPTION +TMF +Initial Time Magnification factor on seepage (ATYPE = 3,4 only). +TARG +FMIN +FMAX +FTIED +CONV +GT.0: Factor (can be used with automatic control, see TARG, +FMIN, FMAX). +LT.0: Load Curve ID giving Time +Magnification Factor versus analysis time. +Target for maximum change of excess pore pressure at any node, +per timestep. If the actual change falls below the target, the time +factor on the seepage calculation will be increased . If +zero, the constant value of TMF is used. If non-zero, TMF is taken +as the initial factor. +Minimum time factor on seepage calculation +Maximum time factor on seepage calculation +Analysis type for pore water pressure calculations: +EQ.0.0: Tied contacts act as impermeable membranes, +EQ.1.0: Fluid may flow freely through tied contacts. +Convergence tolerance for ATYPE = 4. Maximum head change +per time step at any node as measured in units of characteristic +length, l. +𝑙 = +𝜌𝑔 +where, +𝜌 = pore fluid density, PF_ RHO +𝑔 = gravitational acceleration. +CONMAX +Maximum factor on permeability with ATYPE = -4 +ETERM +Event time termination (ATYPE = 3) +THERM +Thermal expansion: Volumetric strain per degree increase for +undrained soil. +ETFLAG +Flag for interpretation of time etc : +EQ.0: Time means analysis time, +EQ.1: Time means event time. +Undrained +*CONTROL_PORE_FLUID +For analyses of the “undrained” type the pore fluid is trapped within the materi- +al. Volume changes result in pore pressure changes. This approximation is used +to simulate the effect of rapidly-applied loads on relatively impermeable soil. +Drained +For analyses of the “drained” type the pore fluid is free to move within the +material such that the user-defined pressure-versus-z-coordinate relationship is +always maintained. This approximation is used to model high-permeability +soils. +Time-dependent consolidation +For the analysis type “time dependent consolidation,” pressure gradients cause +pore fluid to flow through the material according to Darcy’s law: +where, +v = κ∇(p + z) +v = fluid velocity vector +κ = permeability +p = pressure head +z = z-coordinate. +Net inflow or outflow at a node leads to a theoretical volume gain or loss. The +analysis is coupled, i.e. any difference between actual and theoretical volume +leads to pore pressure change, which in turn affects the fluid flow. The result is a +prediction of response-versus-time. +Steady-state consolidation +For the analysis type “steady-state consolidation,” an iterative method is used to +calculate the steady-state pore pressure. The analysis is uncoupled, i.e. only the +final state is meaningful, not the response-versus-time. +Time factoring: +Consolidation occurs over time intervals of days, weeks or months. To simulate this +process using explicit time integration, a time factor is used. The permeability of the +soil is increased by the time factor so that consolidation occurs more quickly. The +output times in the D3PLOT and D3THDT files are modified to reflect the time factor. +The factored time (“Event Time”) is intended to represent the time taken in the real-life +consolidation process and will usually be much larger than the analysis time (the +analysis time is the sum of the LS-DYNA timesteps). The time factor may be chosen +explicitly (using TMF) but it is recommended to use automatic factoring instead. The +automatic scheme adjusts the time factor according to how quickly the pore pressure is +changing; usually at the start of consolidation the pore pressure changes quickly and +the time factor is low; the time factor increases gradually as the rate of pore pressure +change reduces. Automatic time factoring is input by setting TARG (the target pore +pressure head change per timestep) and maximum and minimum allowable time +factors, for example TARG = 0.001 to 0.01m head, FMIN = 1.0, FMAX = 1.0e6. +Optimum settings for these are model-dependent. +Loading, other input data from loadcurves, and output time-intervals on *DATABASE +cards by default use the analysis time (for example, the x-axis of a loadcurve used for +pressure loading is analysis time). When performing consolidation with automatic +time-factoring, the relationship between analysis time and event time is unpredictable. +Termination based on event time may be input using ETERM. +It may also be desired to apply loads as functions of event time rather than analysis +time, since the event time is representative of the real-life process. By setting +ETFLAG = 2, the time axis of all load curves used for any type of input-versus-time, and +output intervals on *DATABASE cards, will be interpreted as event time. This method +also allows consolidation to be used as part of a staged construction sequence – when +ETFLAG = 2, the stages begin and end at the “real time” stage limits and input curves of +pore pressure analysis type vs. time may be used to enforce, for example, consolidation +in some stages, and undrained behavior in others. +Output: +Extra variables for solid elements are automatically written to the d3plot and d3thdt +files when the model contains *CONTROL_PORE_FLUID. In LS971 R4 onwards, 5 +additional extra variables are written, of which the first is the pore pressure in stress +units. In LS971 R3, 15 additional extra variables are written, of which the seventh is +pore pressure in stress units. These follow any extra variables requested by the user, +e.g. if the user requested 3 extra variables, then in LS971 there will be a total of 8 extra +variables of which the fourth is pore pressure. +Further optional output to d3plot and d3thdt files is available for nodal pore pressure +variables – see *DATABASE_PWP_OUTPUT. +For time-dependent and steady-state consolidation, information on the progress of the +analysis is written to d3hsp file. +Remarks: +1. Tied Contacts. By default, the mesh discontinuity at a tied contact will act as a +barrier to fluid flow. If the flag FTIED is set to 1, then pore fluid will be trans- +mitted across tied nodes in tied contacts (*CONTACT_TIED_SURFACE_TO_- +SURFACE and *CONTACT_TIED_NODES_TO_SURFACE, including_OFFSET +and non-_OFFSET types). This algorithm has an effect only when the analysis +type of at least one of the contacting parts is 3, 4 or 6. +2. Thermal. Note that this property is for VOLUMETRIC strain increase. Typical +thermal expansion coefficients are linear; the volumetric expansion will be three +times the linear thermal expansion coefficient. Regular thermal expansion +coefficients (e.g. on *MAT or *MAT_ADD_THERMAL_EXPANSION) apply to +the soil skeleton and to drained parts. Pore pressure can be generated due to +the difference of expansion coefficients of the soil skeleton and pore fluid. +3. Part Associativity. Pore pressure is a nodal variable, but analysis type and +other pore pressure related inputs are properties of parts. When a node is +shared by elements of different parts, and those parts have different pore pres- +sure inputs, the following rules are followed to determine which part’s proper- +ties should be applied to the node. +a) Dry parts (i.e. parts without a *BOUNDARY_PORE_FLUID card) will +never be used (lowest priority). +b) If a part is initially dormant (due to staged construction inputs), it has +next-lowest priority +c) Parts with analysis type = drained have highest priority. +d) Next, higher permeability gives higher priority +e) If two or more parts have equal-highest priority at a node, the part with +lowest ID will win. +4. Related Cards: +*BOUNDARY_PORE_FLUID. +(This card is essential since without this card, no parts will have pore flu- +id.) +*BOUNDARY_PWP_OPTION +*DATABASE_PWP_OUTPUT +*DATABASE_PWP_FLOW +*MAT_ADD_PERMEABILITY +*CONTROL +Purpose: Set parameters for pore air pressure calculations. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +AIR_RO +AIR_P +ETERM +ANAMSG +Type +F +F +F +Default +(none) +(none) +endtim +I +0 + VARIABLE +DESCRIPTION +PA_RHO +Density of atmospheric air, = 1.184 kg/m3 at 25°C +PA_PATM +Pressure of atmospheric air, = 101.325 kPa at 25°C +ETERM +ANAMSG +Event termination time, default to ENDTIME of *CONTROL_- +TERMINATION +Flag to turn off the printing of pore air analysis status message, +including the analysis time, the node with the highest pressure +change. +EQ.0: Status messages are printed, the default value. +EQ.1: Status messages are not printed +*CONTROL_REFINE_ALE +Purpose: Refine ALE hexahedral solid elements locally. Each parent element is +replaced by 8 child elements with a volume equal to 1/8th the parent volume. If only +the 1st card is defined, the refinement occurs during the initialization. The 2nd card +defines a criterion CRITRF to automatically refine the elements during the run. If the 3rd +card is defined, the refinement can be removed if a criterion CRITRM is reached: the +child elements can be replaced by their parents. + Card 1 +Variable +1 +ID +2 +3 +4 +5 +6 +7 +8 +TYPE +NLVL +MMSID +IBOX +IELOUT +Type +I +Default +none +I +0 +I +1 +I +0 +I +0 +I +0 +Remaining cards are optional.† +Automatic refinement card. Optional card for activating automatic refinement +whereby each element satisfying certain criteria is replaced by a cluster of 8 child +elements + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NTOTRF NCYCRF +CRITRF +VALRF +BEGRF +ENDRF +LAYRF +DELAYRF +Type +Default +I +0 +F +0.0 +I +0 +F +F +F +0.0 +0.0 +0.0 +I +0 +F +0.0 +Automatic Refinement Remove Card. Optional card for activating automatic +refinement removal whereby, when, for a cluster of 8 child elements, certain criteria are +satisfied the clusters is replaced by its parent. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable MAXRM NCYCRM CRITRM +VALRM +BEGRM +ENDRM MMSRM DELAYRM +Type +Default +I +0 +F +0.0 +I +0 +F +F +F +0.0 +0.0 +0.0 +I +0 +F +0.0 + VARIABLE +DESCRIPTION +ID +Set ID. +TYPE +Set type: +EQ.0: ALE Part Set, +EQ.1: ALE Part, +EQ.2: Lagrangian Part Set coupled to ALE , +EQ.3: Lagrangian Part coupled to ALE , +EQ.4: Lagrangian Shell Set coupled to ALE , +EQ.5: ALE Solid Set. +NLVL +Number of refinement levels . +MMSID +Multi-Material Set ID : +LT.0: only ALE elements with all the multi-material groups +listed in *SET_MULTI-MATERIAL_GROUP_LIST can be +refined (or removed otherwise) +GT.0: ALE elements with at least one of the multi-material +groups can be refined (or removed) +IBOX +Box ID defining a region in which the ALE +elements are refined. +IELOUT +Flag to handle child data in elout . +VARIABLE +DESCRIPTION +NTOTRF +Total number of ALE elements to refine : +GT.0: Number of elements to refine +EQ.0: NTOTRF = number of solid elements in IBOX +LT.0: |NTOTRF| is the id of *CONTROL_REFINE_MPP_DIS- +TRIBUTION that computes the number of extra elements +required by processors. +NCYCRF +Number of cycles between each refinement. +LT.0: |NCYCRF| is the time interval +CRITRF +Refinement criterion: +EQ.0: static refinement (as if only the 1st card is defined), +EQ.1: Pressure (if pressure > VALRF), +EQ.2: Relative Volume (if V/Vo < VALRF) , +EQ.3: Volume Fraction (if Volume fraction > VALRF), +EQ.5: User defined criterion. The fortran routine alerfn_ +criteria5 in the file dynrfn_user.f should be used to de- +velop the criterion. The file is part of the general package +usermat. +VALRF +Criterion value to reach for the refinement. +BEGRF +Time to begin the refinement. +ENDRF +Time to end the refinement. +LAYRF +Number of element layers to refine around a element reaching the +refinement criterion . +DELAYRF +Period of time after removing the refinement of an element, +during which this element will not be refined again. +MAXRM +Maximum number of child clusters to remove : +LT.0: for the whole run, +GT.0: every NCYCRM cycles +VARIABLE +DESCRIPTION +NCYCRM +Number of cycles between each check for refinement removal: +LT.0: |NCYCRM| is the time interval +CRITRM +Criterion for refinement removal: +EQ.0: no refinement removal (as if only the 1st and 2nd card +are defined), +EQ.1: Pressure (if pressure < VALRM), +EQ.2: Relative Volume (if V/Vo > VALRM) , +EQ.3: Volume Fraction (if Volume fraction < VALRM), +EQ.5: User defined criterion. The fortran routine alermv_ +criteria5 in the file dynrfn_user.f should be used to devel- +op the criterion. The file is part of the general package +usermat. +VALRM +Criterion value to reach in each child element of a cluster for its +removal (child elements replaced by parent element).. +BEGRM +Time to begin the check for refinement removal: +LT.0: |BEGRM| represents a critical percent of NTOTRF below +which the check for refinement removal should begin +(0.0 < |BEGRM| < 1.0). . +ENDRM +Time to end the check for refinement removal. +MMSRM +Multi-Material Set ID for the refinement removal. +LT.0: | MMSRM | represents the radius of a sphere centered +on a newly refined element, in which the refinement can +not be removed. +DELAYRM +Period of time after refining an element, during which this +refinement will not be removed. +Remarks: +1. +2. +If only the 1st card is defined, only TYPE = 0, 1, 5 can be defined. +*CONSTRAINED_LAGRANGE_IN_SOLID needs to be defined for TYPE = 2, 3, +4. If an ALE element has at least one coupling point , this element will be selected to be re- +fined (or removed). The number of elements to refine is computed during the +initialization. NTOTRF can be zero. Otherwise it can used to add more ele- +ments. +3. +4. +If NLVL = 1, there is only one level of refinement: the ALE elements in *ELE- +MENT_SOLID are the only ones to be replaced by clusters of 8 child elements. +If NLVL > 1, there are several levels of refinement: not only the initial ALE +elements in *ELEMENT_SOLID are refined but also their child elements. +If only the 1st card is defined, a multi-material set id is not used. It can be left to +zero. For the 2nd and 3rd cards, MMSID is the ID of *SET_MULTI-MATERIAL_- +GROUP_LIST in which the multi-material group ids (as defined in *ALE_MUL- +TI-MATERIAL_GROUP) are listed to select the ALE elements to be refined (or +removed). If MMSID < 0, only mixed ALE elements containing all the multi- +material groups can be refined. Otherwise clusters of 8 elements without a mix +of the listed multi-material groups can be removed. +5. NTOTRF defines the total number of ALE elements to be refined. So for +example NTOTRF = 100 with NLVL = 1 means that only 100 ALE elements can +be replaced by 800 ALE finer elements (or 100 clusters of 8 child elements). For +NLVL = 2, these 800 elements can be replaced by 6400 finer elements. +6. +7. +8. +If an element is refined, it is possible to refine the neighbor elements as well. +LAYRF defines the number of neighbor layers to refine. For example, +LAYRF = 2 for an element at the center of a block of 5 × 5 × 5 elements will +refine these 125 elements. +If MMSRM = 0, MMSID defines the multi-material region where the check for +refinement removal should occur. If MMSRM is defined, only ALE child ele- +ments fully filled by the multi-material groups listed by the set MMSRM can be +removed (if the refinement removal criterion is reached). +If BEGRM < 0, the check for refinement removal is activated when the number +of 8-element clusters for the refinement is below a limit defined by +|BEGRM|*NTOTRF. If |BEGRM| = 0.1, it means that the check for refinement +removal starts when 90% of the stock of clusters is used for the refinement. +9. MAXRM < 0 defines a total number of child clusters to remove for the whole +run. If positive, MAXRM defines an upper limit for the number of child clus- +ters to remove every NCYCRM cycles. +10. If only the 1st card is defined, the code for IELOUT is always activated. Since +the refinement occurs during the initialization, every refined element is re- +placed by its 8 children in the set defined for *DATABASE_ELOUT. +11. If there are more than 1 line, the code for IELOUT is activated if the flag is equal +to 1. Since the refinement occurs during the run, the parent ids in the set de- +fined for *DATABASE_ELOUT are duplicated 8NLVL times. The points of inte- +gration in the elout file are incremented to differentiate the child contributions +to the database. +*CONTROL_REFINE_ALE2D +Purpose: Refine ALE quadrilateral shell elements locally. Each parent element is +replaced by 4 child elements with a volume equal to 1/4th the parent volume. If only +the 1st card is defined, the refinement occurs during the initialization. The 2nd card +defines a criterion CRITRF to automatically refine the elements during the run. If the 3rd +card is defined, the refinement can be removed if a criterion CRITRM is reached: the +child elements can be replaced by their parents. + Card 1 +Variable +1 +ID +2 +3 +4 +5 +6 +7 +8 +TYPE +NLVL +MMSID +IBOX +IELOUT +Type +I +Default +none +I +0 +I +1 +I +0 +I +0 +I +0 +Remaining cards are optional.† +Automatic refinement card. Optional card for activating automatic refinement +whereby each element satisfying certain criteria is replaced by a cluster of 4 child +elements + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NTOTRF NCYCRF +CRITRF +VALRF +BEGRF +ENDRF +LAYRF +Type +Default +I +0 +F +0.0 +I +0 +F +F +F +0.0 +0.0 +0.0 +I +Automatic Refinement Remove Card. Optional card for activating automatic +refinement removal whereby, when, for a cluster of 4 child elements, certain criteria are +satisfied the clusters is replaced by its parent. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable MAXRM NCYCRM CRITRM +VALRM +BEGRM +ENDRM MMSRM +Type +Default +I +0 +F +0.0 +I +0 +F +F +F +0.0 +0.0 +0.0 +I +0 + VARIABLE +DESCRIPTION +ID +Set ID. +TYPE +Set type: +EQ.0: ALE Part Set, +EQ.1: ALE Part, +EQ.2: Lagrangian Part Set coupled to ALE , +EQ.3: Lagrangian Part coupled to ALE , +EQ.4: Lagrangian Shell Set coupled to ALE , +EQ.5: ALE Shell Set. +NLVL +Number of refinement levels . +MMSID +Multi-Material Set ID : +LT.0: only ALE elements with all the multi-material groups +listed in *SET_MULTI-MATERIAL_GROUP_LIST can be +refined (or removed otherwise) +GT.0: ALE elements with at least one of the multi-material +groups can be refined (or removed) +IBOX +Box ID defining a region in which the ALE +elements are refined. +IELOUT +Flag to handle child data in elout . +VARIABLE +DESCRIPTION +NTOTRF +Total number of ALE elements to refine : +GT.0: Number of elements to refine +EQ.0: NTOTRF = number of shell elements in IBOX +NCYCRF +Number of cycles between each refinement. +LT.0: |NCYCRF| is the time interval +CRITRF +Refinement criterion: +EQ.0: static refinement (as if only the 1st card is defined), +EQ.1: Pressure (if pressure > VALRF), +EQ.2: Relative Volume (if V/Vo < VALRF) , +EQ.3: Volume Fraction (if Volume fraction > VALRF), +EQ.5: User defined criterion: The +routine al2rfn_ +criteria5 in the file dynrfn_user.f should be used to de- +velop the criterion. The file is part of the general pack- +age usermat. +fortran +VALRF +Criterion value to reach for the refinement. +BEGRF +Time to begin the refinement. +ENDRF +Time to end the refinement. +LAYRF +Number of element layers to refine around a element reaching the +refinement criterion . +MAXRM +Maximum number of child clusters to remove : +LT.0: for the whole run, +GT.0: every NCYCRM cycles +NCYCRM +Number of cycles between each check for refinement removal: +LT.0: |NCYCRM| is the time interval +VARIABLE +DESCRIPTION +CRITRM +Criterion for refinement removal: +EQ.0: no refinement removal (as if only the 1st and 2nd card +are defined), +EQ.1: Pressure (if pressure < VALRM), +EQ.2: Relative Volume (if V/Vo > VALRM) , +EQ.3: Volume Fraction (if Volume fraction < VALRM), +EQ.5: User defined criterion: The fortran routine al2rmv_ +criteria5 in the file dynrfn_user.f should be used to devel- +op the criterion. The file is part of the general package +usermat. +VALRM +Criterion value to reach in each child element of a cluster for its +removal (child elements of a cluster replaced by parent element). +BEGRM +Time to begin the check for refinement removal: +LT.0: |BEGRM| represents a critical percent of NTOTRF below +which the check for refinement removal should begin +(0.0 < |BEGRM| < 1.0). . +ENDRM +Time to end the check for refinement removal. +MMSRM +Multi-Material Set ID for the refinement removal. +Remarks: +1. +2. +3. +If only the 1st card is defined, only TYPE = 0,1,5 can be defined. +*CONSTRAINED_LAGRANGE_IN_SOLID needs +for +TYPE = 2,3,4. If an ALE element has at least one coupling point , this element will be selected to be +refined (or removed). +be defined +to +If NLVL = 1, there is only one level of refinement: the ALE elements in *ELE- +MENT_SHELL are the only ones to be replaced by clusters of 4 child elements. +If NLVL > 1, there are several levels of refinement: not only the initial ALE +elements in *ELEMENT_SHELL are refined but also their child elements. If +NLVL = 2 for example, the initial ALE elements can be replaced by clusters of +16 child elements. +4. +If only the 1st card is defined, a multi-material set id is not used. It can be left to +zero. For the 2nd and 3rd cards, MMSID is the ID of *SET_MULTI-MATERIAL_- +GROUP_LIST in which the multi-material group ids (as defined in *ALE_MUL- +TI-MATERIAL_GROUP) are listed to select the ALE elements to be refined (or +removed). If MMSID < 0, only mixed ALE elements containing all the multi- +material groups can be refined. Otherwise clusters of 4 elements without a mix +of the listed multi-material groups can be removed. +5. NTOTRF defines the total number of ALE elements to be refined. So for +example NTOTRF = 100 means that only 100 ALE elements will be replaced by +400 ALE finer elements (or 100 clusters of 4 child elements). For NLVL = 2, +these 400 elements can be replaced by 1600 finer elements. +6. +7. +8. +If an element is refined, it is possible to refine the neighbor elements as well. +LAYRF defines the number of neighbor layers to refine. For example, +LAYRF = 2 for an element at the center of a block of 5 × 5 elements will refine +these 25 elements. +If MMSRM = 0, MMSID defines the multi-material region where the check for +refinement removal should occur. If MMSRM is defined, only ALE child ele- +ments fully filled by the multi-material groups listed by the set MMSRM can be +removed (if the refinement removal criterion is reached). +If BEGRM < 0, the check for refinement removal is activated when the number +of 4-element clusters for the refinement is below a limit defined by +|BEGRM|*NTOTRF. If |BEGRM| = 0.1, it means that the check for refinement +removal starts when 90% of the stock of clusters is used for the refinement. +9. MAXRM < 0 is the exact opposite of NTOTRF > 0 and it defines a total number +of child clusters to remove for the whole run. If positive, MAXRM defines an +upper limit for the number of child clusters to remove every NCYCRM cycles +10. If only the 1st card is defined, the code for IELOUT is always activated. Since +the refinement occurs during the initialization, every refined element is re- +placed by its 4 children in the set defined for *DATABASE_ELOUT. +11. If there are more than 1 line, the code for IELOUT is activated if the flag is equal +to 1. Since the refinement occurs during the run, the parent ids in the set de- +fined for *DATABASE_ELOUT are duplicated 4NLVL times. The points of inte- +gration in the elout file are incremented to differentiate the child contributions +to the database. +*CONTROL_REFINE_MPP_DISTRIBUTION +Purpose: Distribute the elements for the refinement over the MPP processes. This +keyword addresses to the following situation: +If TYPE = 2, 3, 4 in *CONTROL_REFINE_ALE, the refinement occurs around a +structure. The number of elements for this refinement is computed for each +process according the initial position of the structure in each MPP subdomain +(after the MPP decomposition of the ALE mesh during the phase 3 of the initiali- +zation, each process has a subdomain that is a portion of the ALE mesh). If the +structure is not in a subdomain, the related process receives no extra element for +the refinement. If the structure moves into this subdomain during the computa- +tion, the refinement around the structure can not occur. To avoid this problem, +the structure can be considered within a box (the structure maxima and minima +give the box dimensions and positions). This box moves and expands during the +computation to keep the structure inside. An estimation of the maximal dis- +placement and expansion will allow the code to evaluate which subdomains the +structure will likely cross and how many extra elements a process may need to +carry out the refinement. +The computation of the number of extra elements per process occurs in 2 steps: +• If a file called “refine_mpp_distribution” does not exist in the working directory, +it will be created to list the number of elements by process. Each line in this file +matches a process rank (starting from 0). After the phase 3 of the MPP decompo- +sition, the run terminates as if *CONTROL_MPP_DECOMPOSITION_SHOW +was activated. +• The model can be run again and the file “refine_mpp_distribution” will be read to +allocate the memory for the extra elements and distribute them across the pro- +cesses. + Card 1 +Variable +1 +ID +Type +I +2 +DX +F +3 +DY +F +4 +DZ +F +5 +EX +F +6 +EY +F +7 +EZ +F +8 +Default +none +0.0 +0.0 +0.0 +1.0 +1.0 +1.0 + VARIABLE +DESCRIPTION +ID +ID = -NTOTRF in *CONTROL_REFINE_ALE +VARIABLE +DESCRIPTION +Dimensionless 𝑥-displacement of the box. . +Dimensionless 𝑦-displacement of the box. . +Dimensionless 𝑧-displacement of the box. . +Dimensionless 𝑥-expansion of the box. . +Dimensionless 𝑦-expansion of the box. . +Dimensionless 𝑧-expansion of the box. . +DX +DY +DZ +EX +EY +EZ +Remarks: +1. Box Displacements. DX, DY and DZ are the maximal displacements of the +box center. These displacements are ratio of the box dimensions. If, for exam- +ple, the largest length of the structure in the x-direction is 10m and the maximal +displacement in this direction is 2m, DX should be equal to 0.2 +2. Maximal Box Dilations. EX, EY and EZ represent the maximal dilatations of +the box in each direction. These expansions are ratio of the box dimensions. +The box expands around its center. If, for example, the maximal thickness of a +structure along z is 1cm and the structure deforms 30 times the thickness in z- +direction, EZ should be equal to 30 and DZ=15 accounts for the box center mo- +tion. The x-y plane is a plane of symmetry for this deformation, DZ can be zero. +*CONTROL +Purpose: Refine quadrilateral shell elements locally. Each parent element is replaced +by 4 child elements with a volume equal to 1/4th the parent volume. If only the 1st card +is defined, the refinement occurs during the initialization. The 2nd card defines a +criterion CRITRF to automatically refine the elements during the run. If the 3rd card is +defined, the refinement can be removed if a criterion CRITRM is reached: the child +elements can be replaced by their parents. + Card 1 +Variable +1 +ID +2 +3 +4 +5 +6 +7 +8 +TYPE +NLVL +IBOX +IELOUT +Type +I +Default +none +I +0 +I +1 +I +0 +I +0 +Remaining cards are optional.† +Automatic refinement card. Optional card for activating automatic refinement +whereby each element satisfying certain criteria is replaced by a cluster of 4 child +elements + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NTOTRF NCYCRF +CRITRF +VALRF +BEGRF +ENDRF +LAYRF +Type +Default +I +0 +F +0.0 +I +0 +F +F +F +0.0 +0.0 +0.0 +I +Automatic Refinement Remove Card. Optional card for activating automatic +refinement removal whereby, when, for a cluster of 4 child elements, certain criteria are +satisfied the clusters is replaced by its parent. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable MAXRM NCYCRM CRITRM +VALRM +BEGRM +ENDRM +Type +Default +I +0 +F +0.0 +I +0 +F +F +F +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +ID +Set ID. +LT.0: parent elements can be hidden in lsprepost as they are +replaced by their children. +TYPE +Set type:: +EQ.0: Part Set, +EQ.1: Part, +EQ.2: Shell Set. +NLVL +IBOX +Number of refinement levels . +Box ID defining a region in which the +elements are refined. +IELOUT +Flag to handle child data in the elout file . +NTOTRF +Total number of elements to refine : +GT.0: Number of elements to refine +EQ.0: NTOTRF = number of shell elements in IBOX +NCYCRF +Number of cycles between each refinement. +LT.0: |NCYCRF| is the time interval +VARIABLE +DESCRIPTION +CRITRF +Refinement criterion: +EQ.0: static refinement (as if only the 1st card is defined), +EQ.1: Pressure (if pressure > VALRF), +EQ.2: undefined , +EQ.3: Von Mises criterion, +EQ.4: Criterion similar to ADPOPT = 4 in *CONTROL_ADAP- +TIVE (VALRF = ADPTOL), +EQ.5: User defined criterion: The +routine shlrfn_ +criteria5 in the file dynrfn_user.f should be used to devel- +op the criterion. The file is part of the general package +usermat. +fortran +VALRF +Criterion value to reach for the refinement. +BEGRF +Time to begin the refinement. +ENDRF +Time to end the refinement. +LAYRF +Number of element layers to refine around a element reaching the +refinement criterion . +MAXRM +Maximum number of child clusters to remove : +LT.0: for the whole run, +GT.0: every NCYCRM cycles +NCYCRM +Number of cycles between each check for refinement removal: +LT.0: |NCYCRM| is the time interval +VARIABLE +DESCRIPTION +CRITRM +Criterion for refinement removal: +EQ.0: no refinement removal (as if only the 1st and 2nd card +are defined), +EQ.1: Pressure (if pressure < VALRM), +EQ.2: undefined, +EQ.3: Von Mises criterion, +EQ.4: Criterion similar to ADPOPT = 4 in *CONTROL_ADAP- +TIVE (VALRF = ADPTOL), +EQ.5: User defined criterion: The fortran routine shlrmv_ +criteria5 in the file dynrfn_user.f should be used to de- +velop the criterion. The file is part of the general pack- +age usermat. +VALRM +Criterion value to reach in each child elements of a cluster for its +removal (child elements replaced by parent element). +BEGRM +Time to begin the check for refinement removal. +LT.0: |BEGRM| represents a critical percent of NTOTRF below +which the check for refinement removal should begin +(0.0 < |BEGRM| < 1.0). . +ENDRM +Time to end the check for refinement removal. +Remarks: +1. +If NLVL = 1, there is only one level of refinement: the elements in *ELEMENT_- +SHELL are the only ones to be replaced by clusters of 4 child elements. If +NLVL > 1, there are several levels of refinement: not only the initial elements in +*ELEMENT_SHELL are refined but also their child elements. If NLVL = 2 for +example, the initial elements can be replaced by clusters of 16 child elements. +2. NTOTRF defines the total number of elements to be refined. So for example +NTOTRF = 100 with NLVL = 1 means that only 100 elements can be replaced by +400 finer elements (or 100 clusters of 4 child elements). For NLVL = 2, these 400 +elements can be replaced by 1600 finer elements. +3. +If an element is refined, it is possible to refine the neighbor elements as well. +LAYRF defines the number of neighbor layers to refine. For example, +LAYRF = 2 for an element at the center of a block of 5 × 5 elements will refine +these 25 elements. +4. +If BEGRM < 0, the check for refinement removal is activated when the number +of 4-element clusters for the refinement is below a limit defined by |BEGRM| × +NTOTRF. If |BEGRM| = 0.1, it means that the check for refinement removal +starts when 90% of the stock of clusters is used for the refinement. +5. MAXRM < 0 defines a total number of child clusters to remove for the whole +run. If positive, MAXRM defines an upper limit for the number of child clus- +ters to remove every NCYCRM cycles. +6. +7. +If only the 1st card is defined, the code for IELOUT is always activated. Since +the refinement occurs during the initialization, every refined element is re- +placed by its 4 children in the set defined for *DATABASE_ELOUT. +If there are more than 1 line, the code for IELOUT is activated if the flag is equal +to 1. Since the refinement occurs during the run, the parent ids in the set de- +fined for *DATABASE_ELOUT are duplicated 4NLVL times. The points of inte- +gration in the elout file are incremented to differentiate the child contributions +to the database. +*CONTROL_REFINE_SOLID +Purpose: Refine hexahedral solid elements locally. Each parent element is replaced by +8 child elements with a volume equal to 1/8th the parent volume. If only the 1st card is +defined, the refinement occurs during the initialization. The 2nd card defines a criterion +CRITRF to automatically refine the elements during the run. If the 3rd card is defined, +the refinement can be removed if a criterion CRITRM is reached: the child elements can +be replaced by their parents. + Card 1 +Variable +1 +ID +2 +3 +4 +5 +6 +7 +8 +TYPE +NLVL +IBOX +IELOUT +Type +I +Default +none +I +0 +I +1 +I +0 +I +0 +Remaining cards are optional.† +Automatic refinement card. Optional card for activating automatic refinement +whereby each element satisfying certain criteria is replaced by a cluster of 8 child +elements + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NTOTRF NCYCRF +CRITRF +VALRF +BEGRF +ENDRF +LAYRF +Type +Default +I +0 +F +0.0 +I +0 +F +F +F +0.0 +0.0 +0.0 +I +Automatic Refinement Remove Card. Optional card for activating automatic +refinement removal whereby, when, for a cluster of 8 child elements, certain criteria are +satisfied the clusters is replaced by its parent. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable MAXRM NCYCRM CRITRM +VALRM +BEGRM +ENDRM +Type +Default +I +0 +F +0.0 +I +0 +F +F +F +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +ID +Set ID. +LT.0: parent elements can be hidden in lsprepost as they are +replaced by their children. +TYPE +Set type: +EQ.0: Part Set, +EQ.1: Part, +EQ.2: Solid Set. +NLVL +IBOX +Number of refinement levels. See Remark 1. +Box ID defining a region in which the +elements are refined. +IELOUT +Flag to handle child data in elout. See Remarks 6 and 7. +NTOTRF +Total number of elements to refine. See Remark 2. +GT.0: Number of elements to refine +EQ.0: NTOTRF = number of solid elements in IBOX +NCYCRF +Number of cycles between each refinement. +LT.0: |NCYCRF| is the time interval +VARIABLE +DESCRIPTION +CRITRF +Refinement criterion: +EQ.0: static refinement as if only the 1st card is defined, +EQ.1: Pressure, if pressure > VALRF, +EQ.2: undefined , +EQ.3: Von Mises criterion. +EQ.5: User defined criterion. The fortran routine sldrfn_ +criteria5 in the file dynrfn_user.f should be used to devel- +op the criterion. The file is part of the general package +usermat. +VALRF +Criterion value to reach for the refinement. +BEGRF +Time to begin the refinement. +ENDRF +Time to end the refinement. +LAYRF +Number of element layers to refine around an element reaching +the refinement criterion. See Remark 3. +MAXRM +Maximum number of child clusters to remove. See Remark 5. +LT.0: for the whole run, +GT.0: every NCYCRM cycles +NCYCRM +Number of cycles between each check for refinement removal: +LT.0: |NCYCRM| is the time interval +CRITRM +Criterion for removal of refinement: +EQ.0: no removal of refinement as if only the 1st and 2nd card +are defined, +EQ.1: Pressure if pressure < VALRM, +EQ.2: undefined, +EQ.3: Von Mises criterion. +EQ.5: User defined criterion. The FORTRAN routine sldrmv_ +criteria5 in the file dynrfn_user.f should be used to devel- +op the criterion. The file is part of the general package +usermat. +VARIABLE +VALRM +DESCRIPTION +Criterion value to reach in each child element of a cluster for its +removal (replace child elements with parent element). +BEGRM +Time to begin check for refinement removal: +LT.0: |BEGRM| represents a critical percent of NTOTRF below +which the check for refinement removal should begin +(0.0 < |BEGRM| < 1.0). See Remark 4. +ENDRM +Time to end the check for refinement removal. +Remarks: +1. Number of Refinement Levels. If NLVL=1, there is only one level of +refinement: the elements in *ELEMENT_SOLID are the only ones to be replaced +by clusters of 8 child elements. If NLVL > 1, there are several levels of refine- +ment: not only the initial elements in *ELEMENT_SOLID are refined but also +their child elements. If NLVL = 2 for example, the initial elements can be re- +placed by clusters of 64 child elements. +2. Maximum Number of Elements to Refine. NTOTRF defines the total number +of elements to be refined. So for example NTOTRF=100 with NLVL=1 means +that only 100 elements can be replaced by 800 finer elements (or 100 clusters of +8 child elements). For NLVL=2, these 800 elements can be replaced by 6400 +finer elements. +3. Number of Layers to Refine. If an element is refined, it is possible to refine +the neighbor elements as well. LAYRF defines the number of neighbor layers to +refine. For example, LAYRF=2 for an element at the center of a block of +5 × 5 × 5 elements will refine these 125 elements. +4. Onset of Refinement Removal. If BEGRM < 0, the check for refinement +removal is activated when the number of 8-element clusters for the refinement +is below a limit defined by |BEGRM| × NTOTRF. If |BEGRM| = 0.1, it means +that the check for refinement removal starts when 90% of the stock of clusters +are used for the refinement. +5. Maximum Refinement Removal. MAXRM < 0 defines a total number of child +clusters to remove for the whole run. If positive, MAXRM defines an upper +limit for the number of child clusters to remove every NCYCRM cycles. +6. The “elout” Database and Initial Refinement. If only the 1st card is defined, +the code for IELOUT is always activated. Since the refinement occurs during +the initialization, every refined element is replaced by its 8 children in the set +defined for *DATABASE_ELOUT. +7. The “elout” Database and Refinement at Run Time. If there are more than 1 +line, the code for IELOUT is activated if the flag is equal to 1. Since the refine- +ment occurs during the run, the parent ids in the set defined for *DATABASE_- +ELOUT are duplicated 8NLVL times. The points of integration in the elout file +are incremented to differentiate the child contributions to the database. +*CONTROL_REMESHING_{OPTION} +Available options include: + +EFG +Purpose: Provide control over the remeshing of solids which are meshed with the solid +tetrahedron element type 13 and mesh-free solid types 41, 42. The element size for +three-dimensional adaptivity can be set on the surface mesh of the solid part, and +adaptivity can be activated based on the criteria of volume loss, mass increase, or +minimum time step size. In addition, so-called interactive adaptivity triggers can be +invoked using the EFG option. +There are two types of 3-D solid adaptivity affected by *CONTROL_REMESHING: +1. General tetrahedral adaptivity for which the EFG option of *CONTROL_- +REMESHING may be invoked. See ADPOPT = 2 in *PART. +2. Axisymmetric adaptivity, sometimes called orbital adaptivity, in which +remeshing is done with hexahedral and pentahedral elements. See AD- +POPT = 3 in *PART. The EFG option of *CONTROL_REMESHING does not +apply for this type of adaptivity. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RMIN +RMAX +VF_LOSS MFRAC +DT_MIN +ICURV +CID +SEGANG +Type +F +F +F +F +Default +none +none +1.0 +0.0 +F +0. +I +4 +I +0 +F +0.0 +Additional card for EFG option. + Card 2 +1 +Variable +IVT +Type +Default +I +1 +LS-DYNA R10.0 +2 +IAT +I +0 +3 +4 +5 +6 +7 +8 +IAAT +IER +MM +I +0 +I +0 +Second additional card for EFG option. This card is optional. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IAT1 +IAT2 +IAT3 +Type +F +F +F +Default +1020 +1020 +1020 + VARIABLE +DESCRIPTION +RMIN +RMAX +VF_LOSS +MFRAC +DT_MIN +Minimum edge length for the surface mesh surrounding the parts +which should be remeshed. +Maximum edge length for the surface mesh surrounding the parts +which should be remeshed. +Volume fraction loss required in a type 13 tetrahedral elements to +trigger a remesh. In the type 13 solid elements, the pressures are +computed at the nodal points; therefore, it is possible for volume +to be conserved but for individual tetrahedrons to experience a +significant volume loss or gain. The volume loss can lead to +numerical problems. Recommended values for VF_LOSS in the +range of 0.10 to 0.30 may be reasonable. +Mass ratio gain during mass scaling required for triggering a +remesh. For a one percent increase in mass, set MFAC = 0.010. +This variable applies to both to general three dimensional +tetrahedral remeshing and to three dimensional axisymmetric +remeshing. +Time step size required for triggering a remesh. This option +applies only to general three dimensional tetrahedral remeshing +and is checked before mass scaling is applied and the time step +size reset. +ICURV +Define number of element along the radius in the adaptivity. See +remark 3. +VARIABLE +CID +DESCRIPTION +Coordinate system ID for three dimensional axisymmetric +remeshing. The z-axis in the defined coordinate system is the +orbital axis, and has to be parallel to the global z-axis in the +current axisymmetric remesher. +EQ.0: use global coordinate, and the global 𝑧-axis is the orbital +axis (default) +SEGANG + For Axisymmetric 3-D remeshing: Angular +element +size + For General (tet) 3-D remeshing: Critical angle specified +in +radians to preserve feature +lines. +(degrees). +IVT +Internal variable transfer in adaptive EFG. +EQ.1: Moving Least square approximation with Kronecker- +delta property (recommended in general case). +EQ.-1: Moving +square +Least +Kronecker-delta property. +approximation without +EQ.2: Partition of unity approximation with Kronecker-delta +property. +EQ.-2: Partition of unity approximation without Kronecker- +delta property. +EQ.-3: Finite element approximation. +IAT +Flag for interactive adaptivity. +EQ.0: No interactive adaptivity. +EQ.1: Interactive adaptivity +combined with predefined +adaptivity. +EQ.2: Purely interactive adaptivity. The time interval between +two successive adaptive steps is bounded by ADPFREQ. +EQ.3: Purely interactive adaptivity. +IAAT +Interactive adaptivity adjustable tolerance. +EQ.0: The tolerance to trigger interactive adaptivity is not +adjusted. +EQ.1: The tolerance is adjusted in run-time to avoid over- +activation. +IER +*CONTROL_REMESHING +DESCRIPTION +Interactive adaptive remeshing with element erosion for metal +cutting. +EQ.1: The failed elements are eroded and the cutting surface is +reconstructed before adaptive remeshing. The current +implementation only supports SMP and IAT = 1, 2, 3. +MM +Interactive adaptive remeshing with monotonic resizing. +EQ.1: The adaptive remeshing can not coarsen a mesh. The +current implementation only supports IAT = 1, 2, 3 and +IER = 0. +Shear strain tolerance for interactive adaptivity. If the shear +strain in any +formulation 42 EFG tetrahedral element exceeds IAT1, remeshing +is triggered. (0.1 ~ 0.5 is recommended). +𝐿max/𝐿min tolerance where 𝐿max and 𝐿min are the maximum and +minimum edge lengths of any given formulation 42 EFG +tetrahedral element. If this ratio in any element exceeds IAT2, +remeshing is triggered. (RMAX/RMIN is recommended.) +Volume change tolerance. If the normalized change in volume of +any formulation 42 tetrahedral element, defined as ∣𝑣1 − 𝑣0∣/∣𝑣0∣ +where 𝑣1 is the current element volume and 𝑣0 is the element +volume immediately after the most recent remeshing, exceeds +IAT3, remeshing is triggered. (0.5 is recommended.) +IAT1 +IAT2 +IAT3 +Remarks: +1. The value of RMIN and RMAX should be of the same order. The value of +RMAX can be set to 2-5 times greater than RMIN. +2. When interactive adaptivity is invoked (IAT > 0), even if none of the tolerances +IAT1, IAT2, and IAT3 for the three respective indicators (shear strain, edge +length ratio, normalized volume change) are exceeded, remeshing will still be +triggered if any of the three indicators over a single explicit time step changes +by more than 50%, that is, if +|[value]𝑛 − [value]𝑛−1| +|[value]𝑛−1| +> 0.5 +where [value]𝑛 denotes value of indicator in nth (current) time step and +[value]𝑛−1 denotes value of indicator in previous time step . This condition is +checked only if [value]𝑛−1 is nonzero. +3. +ICURV represents a number of elements and applies only when ADPENE > 0 in +*CONTROL_ADAPTIVE. The “desired element size” at each point on slave +contact surface is computed based on the tooling radius of curvature , so that ICURV elements +would be used to resolve a hypothetical 90 degree arc at the tooling radius of +curvature. The value of ICURV is (internally) limited to be >=2 and <=12. The +final adapted element size is adjusted as necessary to fall within the size range +set forth by RMIN and RMAX. +*CONTROL_REQUIRE_REVISION +Purpose: To prevent the model from being run in old versions of LS-DYNA. This +might be desirable due to known improvements in the program, required capability, +etc. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable RELEASE REVISION +Type +C +I +Default +none +none + VARIABLE +RELEASE +DESCRIPTION +The release of code required. This should be a string such as +“R6.1.0” or “R7.0” +REVISION +The minimum revision required. This corresponds to the “SVN +Version” field in the d3hsp file. +Remarks: +1. Any number of lines can appear, indicating for example that a particular +feature was introduced in different release branches at different times. +2. +If the RELEASE field is left empty, then any executable whose development +split from the main SVN trunk after the given REVISION will be allowed. +Example: +*CONTROL_REQUIRE_REVISION +R6.1 79315 +R7.0 78310 + 78304 +This would prevent execution by any R6.1 executable before r79315, any R7.0 before +r78310, and all other executables whose development split from the main trunk before +r78304. Note that no versions of R6.0, R6.0.0, or R6.1.0 are allowed: R6.1 does NOT +imply R6.1.0, no matter what the revision of R6.1.0 – R6.1.0 would have to be explicitly +listed. Similarly, R7.0.0 would not be allowed because it is not listed, and it split from +the trunk in r76398. Any future R8.X executable would be allowed, since it will have +split from the trunk after r78304. +*CONTROL_RIGID +Purpose: Special control options related to rigid bodies and to linearized flexible +bodies, see *PART_MODES. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LMF +JNTF +ORTHMD +PARTM +SPARSE METALF +PLOTEL +RBSMS +Type +Default +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +Remaining cards are optional.† + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NORBIC +Type +Default +I +0 + VARIABLE +LMF +DESCRIPTION +Switch the explicit rigid body joint treatment to an implicit +impose +formulation which uses Lagrange multipliers +prescribed kinematic boundary conditions and joint constraints. +There is a slight cost overhead due to the assembly of sparse +matrix equations which are solved using standard procedures for +nonlinear problems in rigid multi-body dynamics. Lagrange +multiplier flag: +to +EQ.0: explicit penalty formulation +EQ.1: implicit formulation with Lagrange multipliers +VARIABLE +DESCRIPTION +JNTF +Generalized joint stiffness formulation; see Remark 1 below: +EQ.0: incremental update +EQ.1: total formulation (exact) +EQ.2: total formulation intended for implicit analysis +ORTHMD +Orthogonalize modes with respect to each other: +EQ.0: true +EQ.1: false, the modes are already orthogonalized +PARTM +Use global mass matrix to determine part mass distribution. This +mass matrix may contain mass from other parts that share nodes. +See Remark 2 below. +EQ.0: true +EQ.1: false +SPARSE +Use sparse matrix multiply subroutines for the modal stiffness +and damping matrices. See Remark 3. +EQ.0: false, do full matrix multiplies (frequently faster). +EQ.1: true +MATELF +Metal forming option, which should not be used for crash and +other applications involving rigid bodies. Use fast update of rigid +body nodes. If this option is active the rotational motion of all +rigid bodies should be suppressed. +EQ.0: full treatment is used +EQ.1: fast update for metal forming applications +PLOTEL +Automatic generation of *ELEMENT_PLOTEL +STRAINED_NODAL_RIGID_BODY. +for *CON- +EQ.0: no generation +EQ.1: one part is generated for all nodal rigid bodies with the +PID set to 1000000. +EQ.2: one part is generated for each nodal rigid body in the +problem with a part ID of 1000000 + PID, where PID is +the nodal rigid body ID. +RBSMS +*CONTROL_RIGID +DESCRIPTION +Flag to apply consistent treatment of rigid bodies in selective and +conventional mass scaling, Remark 4. +EQ.0: Off +EQ.1: On +NORBIC +Circumvent rigid body inertia check, see Remark 5. +EQ.0: Off +EQ.1: On +Remarks: +1. JNTF. The default behavior is for the relative angles between the two +coordinate systems to be done incrementally. This is an approximation, in +contrast to the total formulation where the angular offsets are computed exact- +ly. The disadvantage of the latter approach is that a singularity exists when an +offset angle equals 180 degrees. In most applications, the stop angles exclude +this possibility and JNTF=1 should not cause a problem. JNTF=2 is implement- +ed with smooth response and especially intended for implicit analysis. +2. PARTM. If the determination of the normal modes included the mass from +both connected bodies and discrete masses, or if there are no connected bodies, +then the default is preferred. When the mass of a given part ID is computed, +the resulting mass vector includes the mass of all rigid bodies that are merged +to the given part ID, but does not included discrete masses. See the keyword: +*CONSTRAINED_RIGID_BODIES. A lumped mass matrix is always assumed. +3. SPARSE. Sparse matrix multipliers save a substantial number of operations if +the matrix is truly sparse. However, the overhead will slow the multipliers for +densely populated matrices. +4. RBSMS. In selective mass scaling, rigid bodies connected to deformable +elements can result in significant addition of inertia due missing terms in the +SMS mass matrix. This problem has been observed in automotive applications +where spotwelds are modeled using constrained nodal rigid bodies. By apply- +ing consistent rigid body treatment significant improvement in accuracy and +robustness are observed at the expense of increased CPU intensity. This flag +also applies to conventional mass scaling as it has been observed that inconsist- +encies for various reasons may result in unstable solution schemes even for this +case. +5. NORBIC. During initialization, the determinant of the rigid body inertia tensor +is checked. If it falls below a tolerance value of 10−30, LS-DYNA issues an error +message and the calculation stops. In some rare cases (e.g. with an adverse +system of units), such tiny values would still be valid. In this case, NORBIC +should be set to 1 to circumvent the implied inertia check. +*CONTROL_SHELL +Purpose: Provide controls for computing shell response. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable WRPANG +ESORT +IRNXX +ISTUPD +THEORY +BWC +MITER +PROJ +Type +F +Default +20. +I +0 +I +-1 +I +0 +I +2 +I +2 +I +1 +I +0 +Remaining cards are optional.† + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable ROTASCL +INTGRD +LAMSHT CSTYP6 +THSHEL +Type +F +Default +1. + Card 3 +1 +I +0 +2 +I +0 +3 +I +1 +4 +I +0 +5 +6 +7 +8 +Variable +PSTUPD SIDT4TU +CNTCO +ITSFLG +IRQUAD W-MODE STRETCH +ICRQ +Type +Default +I +0 +I +0 +I +0 +I +0 +I +F +F +I +0 +inactive +inactive +Card 4 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NFAIL1 +NFAIL4 +PSNFAIL +KEEPCS +DELFR +DRCPSID DRCPRM +INTPERR +Type +I +I +I +Default +inactive +inactive +0 +I +0 +I +0 +I +0 +F +1.0 + VARIABLE +WRPANG +DESCRIPTION +Shell element warpage angle in degrees. If a warpage greater +than this angle is found, a warning message is printed. Default is +20 degrees. +ESORT +Sorting of triangular shell elements to automatically switch +degenerate quadrilateral shell formulations to more suitable +triangular shell formulations. +EQ.0: Do not sort (default). +EQ.1: Sort (switch to C0 triangular shell formulation 4, or if a +quadratic shell, switch to shell formulation 24, or if a +shell formulation with thickness stretch, switch to shell +formulation 27). +EQ.2: Sort (switch to DKT triangular shell formulation 17, or if +a quadratic shell, switch to shell formulation 24). The +DKT formulation will be unstable if used to model an +uncommonly thick, triangular shell. +IRNXX +Shell normal update option. This option affects the Hughes-Liu, +Belytschko-Wong-Chiang, +shell +formulations (including fully integrated shells -16 and 16). The +latter is affected if and only if the warping stiffness option is +active, i.e., BWC = 1. +the Belytschko-Tsay +and +EQ.-2: unique nodal fibers which are incrementally updated +based on the nodal rotation at the location of the fiber, +EQ.-1: recomputed fiber directions each cycle, +EQ.0: default set to -1, +EQ.1: compute on restarts, +EQ.n: compute every n cycles (Hughes-Liu shells only). +ISTUPD +*CONTROL_SHELL +DESCRIPTION +Shell thickness change option for deformable shells. + The +parameter, PSTUPD, on the second optional card allows this +option to be applied by part ID. For crash analysis, neglecting the +elastic component of the strains, ISTUPD = 4, may improve +energy conservation and stability. +EQ.0: no thickness change. +EQ.1: membrane straining causes thickness change in 3 and 4 +node shell elements. This option is very important in +sheet metal forming or whenever membrane stretching is +important. +EQ.2: membrane straining causes thickness change in 8 node +thick shell elements, types 1 and 2. This option is not +recommended for implicit or explicit solutions which use +the fully integrated type 2 elements. Types 3 and 5 thick +shells are continuum based and thickness changes are +always considered. +EQ.3: options 1 and 2 apply. +EQ.4: option 1 applies, but the elastic strains are neglected for +the thickness update. This option only applies to shells +(not thick shells) and the most common elastic-plastic +materials for which the elastic response is isotropic. See +SIDT4TU for selective application of this option. +THEORY +list of shell +Default shell formulation. + For remarks on +formulations, refer to *SECTION_SHELL. +overriding this default and how THEORY may affect contact +behavior, see Remark 2. + For a complete +EQ.1: Hughes-Liu +EQ.2: Belytschko-Tsay (default) +EQ.3: BCIZ triangular shell (not recommended) +EQ.4: C0 triangular shell +EQ.5: Belytschko-Tsay membrane +EQ.6: S/R Hughes Liu +EQ.7: S/R co-rotational Hughes Liu +EQ.8: Belytschko-Leviathan shell +EQ.9: fully integrated Belytschko-Tsay membrane +VARIABLE +DESCRIPTION +EQ.10: Belytschko-Wong-Chiang +EQ.11: Fast (co-rotational) Hughes-Liu +EQ.12: Plane stress (𝑥-𝑦 plane) +EQ.13: Plane strain (𝑥-𝑦 plane) +EQ.14: Axisymmetric solid (𝑦-axis of symmetry) – area +weighted. See Remark 5 +EQ.15: Axisymmetric solid (𝑦-axis of symmetry) – volume +weighted. See Remark 5 +EQ.16: Fully integrated shell element (very fast) +EQ.17: Discrete Kirchhoff triangular shell (DKT) +EQ.18: Discrete Kirchhoff linear shell either quadrilateral or +Triangular with 6DOF per node +EQ.20: C0 linear shell element with 6 DOF per node +EQ.21: C0 linear shell element with 5 DOF per node with the +Pian-Sumihara membrane hybrid quadrilateral mem- +brane +EQ.25: Belytschko-Tsay shell with thickness stretch +EQ.26: Fully integrated shell with thickness stretch +EQ.27: C0 triangular shell with thickness stretch +BWC +Warping stiffness for Belytschko-Tsay shells: +EQ.1: Belytschko-Wong-Chiang warping stiffness added. +EQ.2: Belytschko-Tsay (default). +MITER +Plane stress plasticity option (applies to materials 3, 18, 19, and +24): +EQ.1: iterative plasticity with 3 secant iterations (default), +EQ.2: full iterative plasticity, +EQ.3: radial return noniterative plasticity. May lead to false +results and has to be used with great care. +PROJ +Projection method for the warping stiffness in the Belytschko- +Tsay shell (the BWC option above) and the Belytschko-Wong- +Chiang elements . This parameter applies to +explicit calculations since the full projection method is always +used if the solution is implicit and this input parameter is +VARIABLE +DESCRIPTION +ignored. +EQ.0: drill projection, +EQ.1: full projection. +ROTASCL +Define a scale factor for the rotary shell mass. This option is not +for general use. The rotary inertia for shells is automatically +scaled to permit a larger time step size. A scale factor other than +the default, i.e., unity, is not recommended. +INTGRD +Default through thickness numerical integration rule for shells +and thick shells. If more than 10 integration points are requested, +a trapezoidal rule is used unless a user defined rule is specified. +EQ.0: Gauss integration: If 1-10 integration points are specified, +the default rule is Gauss integration. +EQ.1: Lobatto integration: +If 3-10 integration points are +specified, the default rule is Lobatto. For 2 point integra- +tion, the Lobatto rule is very inaccurate, so Gauss inte- +gration is used instead. Lobatto integration has an +advantage in that the inner and outer integration points +are on the shell surfaces. +LAMSHT +Laminated shell theory flag. Except for those using the Green- +Lagrange strain tensor, laminated shell theory is available for all +thin shell and thick shell materials. It is activated when +LAMSHT = 3, 4, or 5 and by using *PART_COMPOSITE or *IN- +TEGRATION_SHELL to define the + See +Remark 6. +integration rule. +EQ.0: do not update shear corrections, +EQ.1: activate laminated shell theory, +EQ.3: activate laminated thin shells, +EQ.4: activate laminated shell theory for thick shells, +EQ.5: activate laminated shell theory for thin and thick shells. +Coordinate system for the type 6 shell element. The default +system computes a unique local system at each in plane point. +just one system used +The uniform local system computes +throughout the shell element. This involves fewer calculations +and is therefore more efficient. The change of systems has a slight +effect on results; therefore, the older, less efficient method is the +CSTYP6 +VARIABLE +DESCRIPTION +THSHEL +PSTUPD +SIDT4TU +CNTCO +default. +EQ.1: variable local coordinate system (default), +EQ.2: uniform local system. +Thermal shell option (applies only to thermal and coupled +structural thermal analyses). See parameter THERM on DATA- +BASE_EXTENT_BINARY keyword. +EQ.0: No temperature gradient is considered through the shell +thickness (default). +EQ.1: A temperature gradient is calculated through the shell +thickness. +|PSTUPD| is the optional shell part set ID specifying which part +ID’s have or do not have their thickness updated according to +ISTUPD. The shell thickness update as specified by ISTUPD by +default applies to all shell elements in the mesh. +LT.0: these shell parts are excluded from the shell thickness +update +EQ.0: all deformable shells have their thickness updated +GT.0: these shell parts are included in the shell thickness +update +Shell part set ID for parts which use the type 4 thickness update +where elastic strains are ignored. The shell parts in part set +SIDT4TU must also be included in the part set defined by +PSTUPD. SIDT4TU has no effect unless ISTUPD is set to 1 or 3. +Flag affecting location of contact surfaces for shells when NLOC +is nonzero in *SECTION_SHELL or in *PART_COMPOSITE, or +when OFFSET is specified using *ELEMENT_SHELL_OFFSET. +CNTCO is not supported for the slave side of NODES_TO_SUR- +FACE type contacts, neither has it any effect for Mortar contacts. +For Mortar contacts NLOC of OFFSET completely determines the +location of the contact surfaces, as if CNTCO = 1 would be set. +EQ.0: NLOC and OFFSET have no effect on location of shell +contact surfaces. +EQ.1: Contact reference plane coincides +with shell reference surface. +EQ.2: Contact reference plane is affected +VARIABLE +DESCRIPTION +by contact thickness. This is typically not physical. +For automatic contact types, the shell contact surfaces are always, +regardless of CNTCO, offset from a contact reference plane by +half a contact thickness. Contact thickness is taken as the shell +thickness by default but can be overridden, for example, with +input on Card 3 of *CONTACT. +The parameter CNTCO affects how the location of the contact +reference plane is determined. When CNTCO = 0, the contact +reference plane coincides with the plane of the shell nodes. +Whereas when CNTCO = 1, the contact reference plane coincides +with the shell reference surface as determined by NLOC or by +OFFSET. For CNTCO = 2, the contact reference plane is offset +from the plane of the nodes by +or by +– +NLOC +× contact thickness +OFFSET × ( +contact thickness +shell thickness +) +whichever applies. +ITSFLG +Flag to activate/deactivate initial transverse shear stresses (local +shell stress components 𝜎𝑦𝑧 and 𝜎𝑧𝑥) from *INITIAL_STRESS_- +SHELL: +EQ.0: keep transverse shear stresses +EQ.1: set transverse shear stresses to zero +IRQUAD +In plane integration rule for the 8-node quadratic shell element +(shell formulation 23): +EQ.2: 2 × 2 Gauss quadrature (default), +EQ.3: 3 × 3 Gauss quadrature. +Figure 12-86. Illustration of an element in a W-Mode. One pair of opposite +corners go up, and the other pair goes down. The angle, 𝛼, is formed by the +plane of the flat element and by the vector connecting the center to the corner. +See Remark 4. + VARIABLE +W-MODE +STRETCH +DESCRIPTION +W-Mode amplitude for element deletion, specified in degrees. +See Figure 12-86 and Remark 4 for the definition of the angle. +Stretch ratio of element diagonals for element deletion. This +option is activated if and only if either NFAIL1 or NFAIL4 are +nonzero and STRETCH > 0.0. +ICRQ +Continuous treatment across element edges for some specified +result quantities. See Remark 7. +NFAIL1 +EQ.0: not active +EQ.1: thickness and plastic strain +Flag to check for highly distorted under-integrated shell elements, +print a message, and delete the element or terminate. Generally, +this flag is not needed for one point elements that do not use the +warping stiffness. A distorted element is one where a negative +Jacobian exist within the domain of the shell, not just at +integration points. The checks are made away from the CPU +requirements for one point elements. If nonzero, NFAIL1 can be +changed in a restart. +EQ.1: print message and delete element. +EQ.2: print message, write d3dump file, and terminate +GT.2: print message and delete element. When NFAIL1 +elements are deleted then write d3dump file and termi- +nate. These NFAIL1 failed elements also include all shell +elements that failed for other reasons than distortion. +VARIABLE +DESCRIPTION +NFAIL4 +PSNFAIL +KEEPCS +Before the d3dump file is written, NFAIL1 is doubled, so +the run can immediately be continued if desired. +Flag to check for highly distorted fully-integrated shell elements, +print a message and delete the element or terminate. Generally, +this flag is recommended. A distorted element is one where a +negative Jacobian exist within the domain of the shell, not just at +integration points. + The checks are made away from the +integration points to enable the bad elements to be deleted before +an instability leading to an error termination occurs. If nonzero, +NFAIL4 can be changed in a restart. +EQ.1: print message and delete element. +EQ.2: print message, write d3dump file, and terminate +GT.2: print message and delete element. When NFAIL4 +elements are deleted then write d3dump file and termi- +nate. These NFAIL4 failed elements also include all shell +elements that failed for other reasons than distortion. +Before the d3dump file is written, NFAIL4 is doubled, so +the run can immediately be continued if desired. +Optional shell part set ID specifying which part ID’s are checked +by the NFAIL1, NFAIL4, and W-MODE options. If zero, all shell +part ID’s are included. +Flag to keep the contact segments of failed shell elements in the +calculation. The contact segments of the failed shells remain +active until a node shared by the segments has no active shells +attached. Only then are the segments deleted. +EQ.0: Inactive +EQ.1: Active +DELFR +Flag to delete shell elements whose neighboring shell elements +have failed; consequently, the shell is detached from the structure +and moving freely in space. This condition is checked if NFAIL1 +or NFAIL4 are nonzero. +EQ.0: Inactive +EQ.1: Isolated elements are deleted. +EQ.2: Isolated quadrilateral elements and triangular elements +connected by only one node are deleted. +VARIABLE +DESCRIPTION +EQ.3: Elements that are either isolated or connected by only +one node are deleted. +DRCPSID +Part set ID for drilling rotation constraint method . +DRCPRM +Drilling rotation constraint parameter (default = 1.0). +INTPERR +Flag for behavior in case of unwanted interpolation/extrapolation +of initial stresses from *INITIAL_STRESS_SHELL. +EQ.0: Only warning is written, calculation continues (default). +EQ.1: Error exit, calculation stops. +Remarks: +1. Drill versus Full Projections for Warping Stiffness. The drill projection is +used in the addition of warping stiffness to the Belytschko-Tsay and the Be- +lytschko-Wong-Chiang shell elements. This projection generally works well +and is very efficient, but to quote Belytschko and Leviathan: +"The shortcoming of the drill projection is that even elements that are in- +variant to rigid body rotation will strain under rigid body rotation if the +drill projection is applied. On one hand, the excessive flexibility rendered +by the 1-point quadrature shell element is corrected by the drill projection, +but on the other hand the element becomes too stiff due to loss of the rigid +body rotation invariance under the same drill projection". +They later went on to add in the conclusions: +"The projection of only the drill rotations is very efficient and hardly in- +creases the computation time, so it is recommended for most cases. How- +ever, it should be noted that the drill projection can result in a loss of +invariance to rigid body motion when the elements are highly warped. For +moderately warped configurations the drill projection appears quite accu- +rate". +In crashworthiness and impact analysis, elements that have little or no warpage +in the reference configuration can become highly warped in the deformed con- +figuration and may affect rigid body rotations if the drill projection is used, i.e., +DO NOT USE THE DRILL PROJECTION. Of course it is difficult to define +what is meant by "moderately warped". The full projection circumvents these +problems but at a significant cost. The cost increase of the drill projection ver- +sus no projection as reported by Belytschko and Leviathan is 12 percent and by +timings in LS-DYNA, 7 percent, but for the full projection they report a 110 +percent increase and in LS-DYNA an increase closer to 50 percent is observed. +In Version 940 of LS-DYNA the drill projection was used exclusively, but in one +problem the lack of invariance was observed; consequently, the drill projection +was replaced in the Belytschko-Leviathan shell with the full projection and the +full projection is now optional for the warping stiffness in the Belytschko-Tsay +and Belytschko-Wong-Chiang elements. Starting with version 950 the Be- +lytschko-Leviathan shell, which now uses the full projection, is somewhat slow- +er than in previous versions. In general, in light of these problems, the drill +projection cannot be recommended. For implicit calculations, the full projection +method is used in the development of the stiffness matrix. +2. THEORY, ELFORM, and Contact with Tapered Shells. All shell parts need +not share the same element formulation. A nonzero value of ELFORM, given +either in *SECTION_SHELL or *PART_COMPOSITE, overrides the element +formulation specified by THEORY in *CONTROL_SHELL. +When using MPP, THEORY = 1 in *CONTROL_SHELL has special meaning +when dealing with non-uniform-thickness shells, that is, it serves to set the +nodal contact thickness equal to the average of the nodal thicknesses from the +shells sharing that node. Thus when a contact surface is comprised of non- +uniform-thickness shells, THEORY = 1 is recommended and the user still has +the option of setting the actual shell theory using ELFORM in *SECTION_ +SHELL. +3. Drilling Rotation Constraint Method. The drilling rotation constraint method +which is used by default in implicit calculations can be used in explicit calculations as well by +defining an appropriate part set DRCPSID. This might be helpful in situations +where single constraints (e.g. spotwelds) are connected to flat shell element +topologies. The additional drill force can by scaled with DRCPRM (default +value is 1.0), where a moderate value should be chosen to avoid excessive stiff- +ening of the structure. A speed penalty of max. 15 % may be observed with this +option. +4. W-Mode Failure Criterion. The w-mode failure criteria depends on the +magnitude of the w-mode, 𝑤, compared to the approximate side-length ℓ. The +magnitude, 𝑤, is defined as +𝑤 = +[(𝐱1 − 𝐱2) + (𝐱3 − 𝐱4)] ⋅ 𝐧 +where 𝐱𝑖 is the position vector for node 𝑖, and 𝐧 is the element normal vector +evaluated at the centroid. The element normal is the unit vector obtained from +the cross product of the diagonal vectors 𝐚 and 𝐛 as, +𝐚 = 𝐱3 − 𝐱1 +𝐛 = 𝐱4 − 𝐱2 +𝐧 = +𝐚 × 𝐛 +‖𝐚 × 𝐛‖ +. +The failure criteria depends on the ratio of 𝑤 to ℓ, where ℓ is defined as, +ℓ = +⎤ +⎡ +⎥ +⎢ +√2 √ +⎥ +⎢ +⎥ +⎢ +⎣ +⎦ +⏟⏟⏟⏟⏟⏟⏟ +~diagonal length +‖𝐚 × 𝐛‖ +⏟⏟⏟⏟⏟ +~√area +such that the element is deleted when +|𝑤| +≥ tan(WMODE). +The angle 𝛼 in the figure may be identified as, +α = arctan ( +|𝑤| +). +5. 2D Axisymmetric Solid Elements. The 2D axisymmetric solid elements come +in two types: area weighted (type 14) and volume weighted (type 15). +a) High explosive applications work best with the area weighted approach +and structural applications work best with the volume weighted ap- +proach. The volume weighted approach can lead to problems along the +axis of symmetry under very large deformations. Often the symmetry +condition is not obeyed, and the elements will kink along the axis. +b) The volume weighted approach must be used if 2D shell elements are +used in the mesh. Type 14 and 15 elements cannot be mixed in the same +calculation. +6. Lamination Theory. Lamination theory should be activated when the +assumption that shear strain through the shell is uniform and constant becomes +violated. Unless this correction is applied, the stiffness of the shell can be gross- +ly incorrect if there are drastic differences in the elastic constants from ply to +ply, especially for sandwich type shells. Generally, without this correction the +results are too stiff. For the discrete Kirchhoff shell elements, which do not +consider transverse shear, this option is ignored. For thin shells of material +*MAT_ENHANCED_COMPOSITE_ +types, +DAMAGE, and *MAT_GENERAL_VISCOELASTIC, laminated shell theory +may also be done by stiffness correction by setting LAMSHT=1. +*MAT_COMPOSITE_DAMAGE, +7. Continuous Result Quantities. A nodal averaging technique is used to +achieve continuity for some quantities across element edges. Applying this +approach to the thickness field and plastic strains (ICRQ=1) can reduce alternat- +ing weak localizations sometimes observed in metal forming applications when +shell elements get stretch-bended over small radii. This option currently works +with shell element types 2, 4, and 16. A maximum number of 9 through thick- +ness integration points is allowed for this method. A speed penalty of max. 15 +% may be observed with this option. +Purpose: Provide controls for solid element response. +*CONTROL + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ESORT +FMATRX NIPTETS SWLOCL +PSFAIL +T10JTOL +ICOH +TET13K +Type +Default +I +0 +I +0 +I +4 +I +1 +I +0 +F +0. +I +0 +I +0 +This card is optional. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +Variable +PM1 +PM2 +PM3 +PM4 +PM5 +PM6 +PM7 +PM8 +PM9 +PM10 +Type +I +I +I +I +I +I +I +I +I +I +Default +none none none none none none none none none none + VARIABLE +ESORT +DESCRIPTION +Automatic sorting of tetrahedral and pentahedral elements to +avoid use of degenerate formulations for these shapes. See *SEC- +TION_SOLID. +EQ.0: no sorting (default) +EQ.1: sort tetrahedron to type 10; pentahedron to type 15; +cohesive pentahedron types 19 and 20 to types 21 and +22, respectively. +EQ.2: sort +to +tetrahedron +integrated +pentahedron to type 115; fully integrated pentahedron to +type 15; cohesive pentahedron types 19 and 20 to types +21 and 22, respectively. +type 10; 1-point +EQ.3: same as EQ.1 but also print switched elements in messag +file +EQ.4: same as EQ.2 but also print switched elements in messag +file +FMATRX +NIPTETS +SWLOCL +PSFAIL +T10JTOL +*CONTROL_SOLID +DESCRIPTION +Default method used in the calculation of the deformation +gradient matrix. +EQ.1: Update incrementally in time. This is the default for +explicit. +EQ.2: Directly compute F: +This is the default for implicit +and implicit/explicit switching. +Number of integration points used in the quadratic tetrahedron +elements. Either 4 or 5 can be specified. This option applies to +the types 4, 16, and 17 tetrahedron elements. +Output option for stresses in solid elements used as spot welds +with material +and +d3plot/d3part/etc. +*MAT_SPOTWELD. + Affects +elout +EQ.1: Stresses in global coordinate system (default), +EQ.2: Stresses in element coordinate system. +A nonzero PSFAIL has the same effect as setting ERODE = 1 in +*CONTROL_TIMESTEP except that solid element erosion due to +negative volume is limited to only the solid elements in part set +PSFAIL. +In other words, when PSFAIL is nonzero, the time-step-based +criterion for erosion (TSMIN) applies to all solid elements (except +formulations 11 and 12) while the negative volume criterion for +erosion applies only to solids in part set PSFAIL. +Tolerance for jacobian in 4-point 10-noded quadratic tetrahedra +(type 16). If the quotient between the minimum and maximum +jacobian value falls below this tolerance, a warning message is +issued in the messag file. This is useful for tracking badly shaped +elements in implicit analysis that deteriorates convergence, a +value of 1.0 indicates a perfectly shaped element. +VARIABLE +ICOH +TET13K +PM1 – PM10 +DESCRIPTION +Global flag for cohesive element options, interpreted digit-wise as +follows: +ICOH = [𝐿𝐾] = 𝐾 + 10 × 𝐿 +K.EQ.1: Solid elements having ELFORM = 19-22 will be eroded +when neighboring shell or solid elements fail. Only +works for nodewise connected parts, not tied contacts. +K.EQ.0: No cohesive element deletion due to neighbor failure. +L.EQ.0: Default critical time step estimate. +L.EQ.1: Most conservative +estimate. +(smallest) critical +time step +L.EQ.2: Intermediate critical time step estimate. +Set to 1 to invoke a consistent tangent stiffness matrix for the +pressure averaged tetrahedron (type 13). This feature is available +only for the implicit integrator and it is not supported in the +MPP/MPI version. This element type averages the volumetric +strain over adjacent elements to alleviate volumetric locking, +therefore, the corresponding material tangent stiffness should be +treated accordingly. In contrast to a hexahedral mesh where a +node usually connects to fewer than 8 elements, tetrahedral +meshes offer no such regularity. Consequently, for nonlinear +implicit analysis matrix assembly is computationally expensive +and this option is recommended only for linear or eigenvalue +analysis to exploit the stiffness characteristics of the type 13 +tetrahedron. +Components of a permutation vector for nodes that define the 10- +node tetrahedron. The nodal numbering of 10-node tetrahedron +elements is somewhat arbitrary. The permutation vector allows +other numbering schemes to be used. Unless defined, this +permutation vector is not used. PM1 – PM10 are unique numbers +between 1 to 10 inclusive that reorders the input node ID’s for a +10-node tetrahedron into the order used by LS-DYNA. +*CONTROL_SOLUTION +Purpose: To specify the analysis solution procedure if thermal only or coupled thermal +analysis is performed. Other solutions parameters including the vector length and NaN +(not a number) checking can be set. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SOLN +NLQ +ISNAN +LCINT +LCACC +Type +Default +I +0 +I +0 +I +0 +I +100 +I +0 + VARIABLE +DESCRIPTION +SOLN +Analysis solution procedure: +NLQ +ISNAN +LCINT +EQ.0: Structural analysis only, +EQ.1: Thermal analysis only, +EQ.2: Coupled structural thermal analysis. +Define the vector length used in solution. This value must not +exceed the vector length of the system which varies based on the +machine manufacturer. The default vector length is printed at +termination in the messag file. +Flag to check for a NaN in the force and moment arrays after the +assembly of these arrays is completed. This option can be useful +for debugging purposes. A cost overhead of approximately 2% is +incurred when this option is active. +EQ.0: No checking, +EQ.1: Checking is active. +Number of equally spaced points used in curve (*DEFINE_- +CURVE) rediscretization. Curve rediscretization applies only to +curves used in material models. Curves defining loads, motion, +etc. are not rediscretized. +VARIABLE +LCACC +DESCRIPTION +Flag to truncate curves to 6 significant figures for single precision +and 13 significant figures for double precision. The truncation is +done after applying the offset and scale factors specified in *DE- +FINE_CURVE. Truncation is intended to prevent curve values +from deviating from the input value, e.g., 0.7 being stored as +0.69999999. This small deviation was seen to have an adverse +effect in a particular analysis using *MAT_083. In general, curve +truncation is not necessary and is unlikely to have any effect on +results. +EQ.0: No truncation. +NE.0: Truncate. +*CONTROL_SPH +Purpose: Provide controls relating to SPH (Smooth Particle Hydrodynamics). + Card 1 +1 +2 +Variable +NCBS +BOXID +Type +Default +I +1 +I +0 +3 +DT +F +4 +5 +6 +7 +8 +IDIM +MEMORY +FORM +START +MAXV +I +I +1020 +none +150 +I +0 +F +F +0.0 +1015 +Optional Card. + Card 2 +1 +2 +Variable +CONT +DERIV +Type +Default +I +0 +I +0 +3 +INI +I +0 +4 +5 +6 +7 +8 +ISHOW +IEROD +ICONT +IAVIS +ISYMP +I +0 +I +0 +I +0 +I +0 +I +100 + VARIABLE +DESCRIPTION +NCBS +Number of time steps between particle sorting. +BOXID +DT +IDIM +SPH approximations are computed inside a specified BOX. When +a particle has gone outside the BOX, it is deactivated. This will +save computational time by eliminating particles that no longer +interact with the structure. +Death time. Determines when the SPH calculations are stopped. +Space dimension for SPH particles: +EQ.3: for 3D problems +EQ.2: for 2D plane strain problems +EQ.-2: for 2D axisymmetric problems +MEMORY +Defines the initial number of neighbors per particle . +VARIABLE +DESCRIPTION +FORM +Particle approximation theory (Remark 2): +EQ.0: default formulation +EQ.1: renormalization approximation +EQ.2: symmetric formulation +EQ.3: symmetric renormalized approximation +EQ.4: tensor formulation +EQ.5: fluid particle approximation +EQ.6: fluid particle with renormalization approximation +EQ.7: total Lagrangian formulation +EQ.8: total Lagrangian formulation with renormalization +EQ.15: enhanced fluid formulation +EQ.16: enhanced fluid formulation with renormalization +Start time for particle approximation. Particle approximations +will be computed when time of the analysis has reached the value +defined in START. +Maximum value for velocity for the SPH particles. Particles with +a velocity greater than MAXV are deactivated. A negative MAXV +will turn off the velocity checking. +Defines the computation of the particle approximation between +different SPH parts: +EQ.0: Particle approximation is defined (default) +EQ.1: Particle approximation is not computed. Different SPH +materials will not interact with each other and penetra- +tion is allowed unless *DEFINE_SPH_TO_SPH_COU- +PLING is defined. Combined with *SECTION_SPH_IN- +TERACTION, a partial interaction between SPH parts +through normal interpolation method and partially in- +teract through the contact option can be realized. See +*SECTION_SPH_INTERACTION. +START +MAXV +CONT +DERIV +Time integration type for the smoothing length: +EQ.0: 𝑑 +EQ.1: 𝑑 +𝑑𝑡 [ℎ(𝑡)] = 1 +𝑑𝑡 [ℎ(𝑡)] = 1 +𝑑 ℎ(𝑡)∇ ⋅ 𝐯, (default), +𝑑 ℎ(𝑡)(∇ ⋅ 𝐯)1/3 +VARIABLE +DESCRIPTION +INI +Computation of the smoothing length during the initialization: +EQ.0: Bucket sort based algorithm (default, very fast). +EQ.1: Global computation on all the particles of the model. +EQ.2: Based on the mass of the SPH particle. +ISHOW +Display option for deactivated SPH particles: +EQ.0: No distinction in active SPH particles and deactivated +SPH particles when viewing in LS-PrePost. +EQ.1: Deactivated SPH particles are displayed only as points +and active SPH particles are displayed as spheres when +Setting → SPH → Style is set to “smooth” in LS-PrePost. +IEROD +Deactivation control for SPH particles: +EQ.0: Particles remain active. +EQ.1: SPH particles are partially deactivated and stress states +are set to 0 when erosion criteria are satisfied. See Re- +mark 3. +EQ.2: SPH particles are totally deactivated and stress states are +set to 0 when erosion criteria are satisfied. See Remark 3. +ICONT +Controls contact behavior for deactivated SPH particles: +EQ.0: Any contact defined for SPH remains active for +deactivated particles. +EQ.1: Contact is inactive for deactivated particles. +IAVIS +Defines artificial viscosity formulation for SPH elements (Remark +4): +ISYMP +EQ.0: Monaghan type artificial viscosity formulation is used. +EQ.1: Standard type artificial viscosity formulation from solid +element is used (this option is not supported in SPH 2D +and 2D axisymmetric elements). +Defines the percentage of original SPH particles used for memory +allocation of SPH symmetric planes ghost nodes generation +process (default is 100%). Recommended for large SPH particles +models (value range 10~20) to control the memory allocation for +SPH ghost particles with *BOUNDARY_SPH_SYMMETRY_- +PLANE keyword. +*CONTROL +1. Memory. MEMORY is used to determine the initial memory allocation for the +SPH arrays. Its value can be positive or negative. If MEMORY is positive, +memory allocation is dynamic such that the number of neighboring particles is +initially equal to MEMORY but that number is subsequently allowed to exceed +MEMORY as the solution progresses. If MEMORY is negative, memory alloca- +tion is static and |MEMORY| is the maximum allowed number of neighboring +particles for each particle throughout the entire solution. Using this static +memory option can avoid memory allocation problems. +2. Form. Some guidelines for selecting form variable: for most solid structure +applications, form = 1 is recommended for more accurate results around the +boundary area; for fluid or fluid-like material applications, form = 15, 16 with +fluid formulation are recommended (form=16 usually has better accuracy but +requires more CPU time); form = 2, 3 are not recommended for any case; all +SPH formulations with Eulerian kernel (form = 0 to 6, 15 and 16) can be used +for large or extreme large deformation applications but will have tensile insta- +bility issue; all SPH formulations with Lagrangian kernel (form = 7,8) can be +used to avoid tensile instability issue but they can not endure very large defor- +mation, user has to be careful to pick up the right one based on the applications. +Only formulations 0, 1, 15 and 16 are implemented for 2D axisymmetric prob- +lems (dim=-2). Also note that forms 15 and 16 include a smoothing of the pres- +sure field, and are therefore not recommended for materials with failure or +problems with important strain localization. +3. Erosion. The erosion criteria, which triggers particle deactivation when +IEROD=1 or 2, may come from either the material model with *MAT_ADD_- +EROSION or from the ERODE parameter in *CONTROL_TIMESTEP. For IER- +OD=1, SPH particles are partially deactivated (i.e. the stress states of the +deactivated SPH particles will be set to 0, but those particles still remain in the +domain integration for more stable results); For IEROD=2, SPH particles are +totally deactivated: stress states will be set to 0 and the deactivated particles no +more remain in the domain integration. Deactivated particles can be distin- +guished from active particles by setting ISHOW=1. To disable contact for deac- +tivated particles, set ICONT=1. +4. Artificial Viscosity. The artificial viscosity for standard solid elements, which +is active when AVIS=1, is given by: +2 − 𝑄2𝑎𝜀̇𝑘𝑘) +𝑞 = 𝜌𝑙(𝑄1𝑙𝜀̇𝑘𝑘 +𝑞 = 0 +𝜀̇𝑘𝑘 < 0 +𝜀̇𝑘𝑘 ≥ 0 +where 𝑄1 and 𝑄2 are dimensionless input constants which default to 1.5 and +.06, respectively, and 𝑙 is a characteristic length given as the square root of the +area in two dimensions and as the cube root of the volume in three, 𝑎 is the local +sound speed. This formulation, which is consistent with solid artificial viscosi- +ty, has better energy balance for SPH elements. For general applications, Mon- +aghan type artificial viscosity is recommended since this type of artificial +viscosity is specifically designed for SPH particles. +The Monaghan type artificial viscosity, which is active when AVIS = 0, is de- +fined as follows: +𝑞 = +⎧−𝑄2𝑐𝑖𝑗𝜙𝑖𝑗 + 𝑄1𝜙𝑖𝑗 +{{ +𝜌𝑖𝑗 +⎨ +{{ +⎩ +𝑣𝑖𝑗𝑥𝑖𝑗 < 0 +𝑣𝑖𝑗𝑥𝑖𝑗 ≥ 0 +Where, +𝜙𝑖𝑗 = +ℎ𝑖𝑗𝑣𝑖𝑗𝑥𝑖𝑗 +∣𝑥𝑖𝑗∣ ++ 𝜑2 +𝑐 ̅𝑖𝑗 = 0.5(𝑐𝑖 + 𝑐𝑗) +𝜌̅𝑖𝑗 = 0.5(𝜌𝑖 + 𝜌𝑗) +ℎ𝑖𝑗 = 0.5(ℎ𝑖 + ℎ𝑗) +𝜑 = 0.1ℎ𝑖𝑗 +𝑄1, 𝑄2 are input constants. When using Monaghan type artificial viscosity, it is +recommended that the user set both Q1 and Q2 to 1.0 on either the *CON- +TROL_BULK_VISCOSITY or *HOURGLASS keywords; see for example G. R. +Liu. +*CONTROL +Purpose: Provides factors for scaling the failure force resultants of beam spot welds as a +function of their parametric location on the contact segment and the size of the segment. +Also, an option is provided to replace beam welds with solid hexahedron element +clusters. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCT +LCS +T_ORT +PRTFLG +T_ORS +RPBHX +BMSID +ID_OFF +Type +Default +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 + VARIABLE +DESCRIPTION +LCT +LCS +T_ORT +PRTFLG +Load curve ID for scaling the response in tension based on the +shell element size. +Load curve ID for scaling the response in shear based on the shell +element size. +Table ID for scaling the tension response (and shear response if +T_ORS = 0) based on the location of the beam node relative to the +centroid of the shell. +Set this flag to 1 to print for each spot weld attachment: the beam, +node, and shell ID’s, the parametric coordinates that define the +constraint location, the angle used in the table lookup, and the +three scale factors obtained from the load curves and table +lookup. See Figure 12-87. +Figure 12-87. Definition of parameters for table definition. +VARIABLE +DESCRIPTION +Optional table ID for scaling the shear response based on the +location of the beam node relative to the centroid of the shell. +Replace each spot weld beam element with a cluster of RPBHX +solid elements. The net cross-section of the cluster of elements is +dimensioned to have the same area as the replaced beam. RPBHX +may be set to 1, 4, or 8. When RPBHX is set to 4 or 8, a table is +generated to output the force and moment resultants into the +SWFORC file, if this file is active. This table is described by the +keyword: *DEFINE_HEX_SPOTWELD_ASSEMBLY. The ID’s of +the beam elements are used as the cluster spot weld ID’s so the +ID’s in the SWFORC file are unchanged. The beam elements are +automatically deleted from the calculation, and the section and +material data is automatically changed to be used with solid +elements. See Figure 11-24. +Optional beam set ID defining the beam element ID’s that are to +be converted to hex assemblies. If zero, all spot weld beam +elements are converted to hex assemblies. +This optional ID offset applies if and only if BMSID is nonzero. +Beams, which share part ID’s with beams that are converted to +hex assemblies, will be assigned new part ID’s by adding to the +original part ID the value of ID_OFF. If ID_OFF, is zero the new +part ID for such beams will be assigned to be larger than the +largest part ID in the model. +T_ORS +RPBHX +BMSID +ID_OFF +Remarks: +The load curves and table provide a means of scaling the response of the beam spot +welds to reduce any mesh dependencies for failure model 6 in *MAT_SPOTWELD. +Figure 12-88 shows such dependencies that can lead to premature spot weld failure. +Separate scale factors are calculated for each of the beam’s nodes. The scale factors sT, +sS, sOT , and sOS are calculated using the load curves LCT, LCS, table T_ORT, and table +T_ORS, respectively, and are introduced in the failure criteria, +⎢⎡𝑠𝑇𝑠𝑂𝑇𝜎𝑟𝑟 +⎥⎤ +𝐹 (𝜀̇𝑒𝑓𝑓 )⎦ +𝜎𝑟𝑟 +⎣ ++ +⎢⎡ 𝑠𝑆𝑠𝑂𝑆𝜏 +⎥⎤ +𝜏𝐹(𝜀̇𝑒𝑓𝑓 )⎦ +⎣ +− 1 = 0 +If a curve or table is given an ID of 0, its scale factor is set to 1.0. The load curves LCT +and LCS are functions of the characteristic size of the shell element used in the time step +calculation at the start of the calculation. The orientation table is a function of the spot +weld’s isoparametric coordinate location on the shell element. A vector V=(s,t) is +defined from the centroid of the shell to the contact point of the beam’s node. The +arguments for the orientation table are the angle: +Θ = tan−1 [ +min(|𝑠|, |𝑡|) +max(|𝑠|, |𝑡|) +], +and the normalized distance 𝑑 ̅= 𝑑 +𝐷⁄ = max(|𝑠|, |𝑡|). See Figure 12-87 The table is +periodic over a range of 0 (V aligned with either the s or t axis) to 45 degrees (V is along +the diagonal of the element). The table is specified by the angle of V in degrees, ranging +from 0 to 45, and the individual curves give the scale factor as a function of the +normalized distance of the beam node, 𝑑̅̅̅̅̅̅ , for a constant angle. +1.20 +1.00 +0.80 +0.60 +0.40 +0.20 +0.00 +1.20 +1.00 +0.80 +0.60 +0.40 +0.20 +0.00 +_ +. +_ +. +CROSS TENSION +EDGE DIRECTION +. +1.20 +1.00 +0.80 +0.60 +0.40 +0.20 +0.00 +Both side +One side +dynamic +static +10 +12 + Center Point1 Point2 Point3 Point4 Edge +MESH SIZE (mm) +SHEAR +dynamic +static +SPOT BEAM LOCATION +CORNER DIRECTION +Both side +One side +. +1.20 +1.00 +0.80 +0.60 +0.40 +0.20 +0.00 +10 +12 +MESH SIZE (mm) + Center Point1 Point2 Point3 Point4 Corner +SPOT BEAM LOCATION +Figure 12-88 The failure force resultants can depend both on mesh size and +the location of weld relative to the center of the contact segment +Purpose: Define the start time of analysis. +*CONTROL + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +BEGTIM +Type +F + VARIABLE +BEGTIM +DESCRIPTION +Start time of analysis (default = 0.0). Load curves are not shifted to +compensate for the time offset. Therefore, this keyword will change +the results of any calculation involving time-dependent load +curves. +*CONTROL_STAGED_CONSTRUCTION +This control card is used to help break down analyses of construction processes into +stages. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +TSTART +STGS +STGE +ACCEL +FACT +STREF +DORDEL NOPDEL +Type +Default +F +0 +I +0 +I +0 +F +F +0.0 +1.e-6 +I +0 +I +0 +I +0 + VARIABLE +DESCRIPTION +TSTART +Time at start of analysis (normally leave blank) +STGS +STGE +Construction stage at start of analysis +Construction stage at end of analysis +ACCEL +Default acceleration for gravity loading +FACT +Default stiffness and gravity factor for parts before they are +added +STREF +Reference stage for displacements in d3plot file +DORDEL +Dormant part treatment in d3plot file, see notes. +EQ.0: Parts not shown when dormant (flagged as “deleted”), +EQ.1: Parts shown normally when dormant. +NOPDEL +Treatment of pressure loads on deleted elements, see notes. +EQ.0: Pressure loads automatically deleted, +EQ.1: No automatic deletion. +Remarks: +See also *DEFINE_CONSTRUCTION_STAGES and *DEFINE_STAGED_CONSTRUC- +TION_PART. +The staged construction options offer flexibility to carry out the whole construction +simulation in one analysis, or to run it stage by stage. Provided that at least one +construction stage is defined (*DEFINE_CONSTRUCTION_STAGES), a dynain file will +be written at the end of each stage (file names are end_stage001_dynain, etc). These +contain node and element definitions and the stress state; the individual stages can then +be re-run without re-running the whole analysis. To do this, make a new input file as +follows: +• Copy the original input file, containing *DEFINE_CONSTRUCTION_- +STAGES and *DEFINE_STAGED_CONSTRUCTION_PART. +• Delete node and element definitions as these will be present in the dynain file +(*NODE, *ELEMENT_SOLID, *ELEMENT_SHELL, and *ELEMENT_BEAM). +• Delete any *INITIAL cards; the initial stresses in the new analysis will be +taken from the dynain file. +• On *CONTROL_STAGED_CONSTRUCTION set STGS to start at the desired +stage +• Add an *INCLUDE statement referencing, for example, end_stage002_dynain +if starting the new analysis from Stage 3. +• Move or copy the dynain file into the same directory as the new input file. +When STGS is > 1 the analysis starts at a non-zero time (the start of stage STGS). In this +case a dynain file must be included to start the analysis from the stress state at the end +of the previous stage. The end time for stage STGE overrides the termination time on +*CONTROL_TERMINATION. A new dynain file will be written at the end of all stages +from STGS to STGE. +ACCEL and FACT are used with *STAGED_CONSTRUCTION_PART for simpler input +definition of the parts present at different construction stages. +If STGS > 1 and elements have been deleted in a previous stage, these elements will be +absent from the new analysis and should not be referred to (e.g. *DATABASE_HISTO- +RY_SOLID) in the new input file. +TSTART can be used to set a non-zero start time (again, assuming a compatible dynain +file is included). This option is used only if construction stages have not been defined. +STREF allows the user to set a construction stage at the start of which displacements are +considered to be zero – e.g. so that initial analysis stages that achieve a pre-construction +equilibrium do not contribute to contour plots of displacement. The current coordinates +are not modified, only the “initial geometry” coordinates in the d3plot file. If this +analysis starts from a stage later than STREF, the reference geometry will be taken from +the dynain file that was written at the end of the stage previous to STREF – this dynain +file must be in the same directory as the current model for this process to occur. This +feature is not available in MPP. +DORDEL: By default, parts for which *DEFINE_STAGED_CONSTRUCTION_PART is +defined are flagged as “deleted” in the d3plot file at time-states for which the part is not +active (i.e. STGA has not yet been reached). Parts that are deleted because STGR has +been reached are also flagged as “deleted”. When animating the results, the parts +should appear as they become active and disappear as they are deleted. If DORDEL is +non-zero, inactive parts (before STGA) are shown normally. The parts are still shown +as deleted after STGR is reached. +NOPDEL: By default, pressure load “segments” are automatically deleted by LS-DYNA +if they share all four nodes with a deleted solid or shell element. In staged construction, +the user may want to apply pressure load to the surface of an element (A) that is +initially shared with an element (B), where B is deleted during the calculation. For +example, B may be in a layer of soil that is excavated, leaving A as the new top surface. +The default scheme would delete the pressure segment when B is removed, despite the +fact that A is still present. NOPDEL instructs LS-DYNA to skip the automatic deletion +of pressure segments, irrespective of whether the elements have been deleted due to +staged construction or material failure. The user must then ensure that pressure loads +are not applied to nodes no longer supported by an active element. +*CONTROL_STEADY_STATE_ROLLING + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IMASS +LCDMU +LCDMUR +IVEL +SCL_K +Type +Default +I +0 +I +0 +I +0 +I +0 +I + VARIABLE +DESCRIPTION +IMASS +Inertia switching flag +EQ.0: include inertia during an implicit dynamic simulation. +EQ.1: treat steady state rolling subsystems as quasi-static +during implicit dynamic simulations. +LCDMU +Optional load curve for scaling the friction forces in contact. +LCDMUR +Optional load curve for scaling the friction forces in contact +during dynamic relaxation. If LCDMUR isn’t specified, LCDMU +is used. +IVEL +Velocity switching flag. +EQ.0: eliminate the steady state rolling body forces and set the +velocities of the nodes after dynamic relaxation. +EQ.1: keep the steady state rolling body forces after dynamic +relaxation instead of setting the velocities. +Scale factor for the friction stiffness during contact loading and +unloading. The default values are 1.0 and 0.01 for explicit and +implicit, respectively. Any scaling applied here applies only to +contact involving the subsystem of parts defined for steady state +rolling. +SCL_K +Remarks: +1. Treating the steady state rolling subsystems as quasi-static during an implicit +simulation may eliminate vibrations in the system that are not of interest and is +generally recommended. +2. Ramping up the friction by scaling it with LCDMU and LCDMUR may +improve the convergence behavior of implicit calculations. The values of the +load curves should be 0.0 at initial contact and ramp up smoothly to a value of +1.0. +3. After dynamic relaxation, the default behavior is to initialize the nodes with the +velocities required to generate the body forces on elements and remove the +body forces. This initialization is skipped, and the body forces retained, after +dynamic relaxation if IVEL = 1. +4. The friction model in contact is similar to plasticity, where there is an elastic +region during the loading and unloading of the friction during contact. The +elastic stiffness is scaled from the normal contact stiffness. For implicit calcula- +tions, the default scale factor is 0.01, which results in long periods of time being +required to build the friction force, and, in some cases, oscillations in the contact +forces. A value between 10 and 100 produces smoother solutions and a faster +build-up and decay of the friction force as the tire velocity or slip angle is var- +ied, allowing a parameter study to be performed in a single run. +*CONTROL_STRUCTURED_{OPTION} +Available options include: + +TERM +Purpose: Write out an LS-DYNA structured input deck that is largely or wholly +equivalent to the keyword input deck. This option may be useful in debugging errors +that occur during processing of the input file, particularly if error messages of the type +“*** ERROR ##### (STR + ###)” are written. The name of the structured input deck is +“dyna.str”. +Not all LS-DYNA features are supported in structured input format. Some data such +as load curve numbers will be output in an internal numbering system. +If the TERM option is activated, termination will occur after the structured input deck is +written. +Adding “outdeck = s” to the LS-DYNA execution line serves the same purpose as +including *CONTROL_STRUCTURED in the keyword input deck. +*CONTROL_SUBCYCLE_{K}_{L} or +*CONTROL_SUBCYCLE_{OPTION} +Available options for subcycling first form with K and L +𝐾, 𝐿 ∈ {, 1, 2, 4, 8, 16, 32, 64} +Available options for multiscale (OPTION) include: + +MASS_SCALED_PART +MASS_SCALED_PART_SET +Purpose: This keyword is used to activate subcycling or mass scaling (multiscale). The +common characteristic of both methods is that the time step varies from element to +element, thereby eliminating unnecessary stepping on more slowly evolving portions of +the model. These techniques are suited for reducing the computational cost for models +involving large spatial variation in mesh density and/or material characteristics. +Subcycling is described in the LS-DYNA Theory Manual and in detail in Borrvall et.al. +[2014] and may be seen as an alternative to using selective mass scaling, see the +keyword *CONTROL_TIMESTEP. +This keyword comes in two variations: +1. Subcycling. Plain subcycling is activated by the *CONTROL_SUBCYCLE_{𝐾}_ +{𝐿} variant of this keyword. This form of the card should not be included more +than once. It may be used in conjunction with mass scaling to limit the time +step characteristics. +For subcycling, time steps for integration are determined automatically from +the characteristic properties of the elements in the model, with the restriction +that the ratio between the largest and smallest time step is limited by 𝐾. Fur- +thermore, 𝐿 determines the relative time step at which external forces such as +contacts and loads are calculated +For example, *CONTROL_SUBCYCLE_16_4 limits the largest explicit integra- +tion time step to at most 16 times the smallest. Contact forces are evaluated +every 4 time steps. The defaults are 𝐾 = 16 and 𝐿 = 1, and L cannot be speci- +fied larger than 𝐾. This option may be used without mass scaling activated but +internally elements may still be slightly mass scaled to maintain computational +efficiency. +2. Mass Scaling/Multiscale. For a multiscale simulation, mass scaling is +mandatory and the time steps are directly specified in the input. The specified +parts or part sets run at the time step +specified in the TS field. All other elements evolve with a time step set by +|DT2MS|, which is set on *CONTROL_TIMESTEP card. +This feature was motivated by automotive crash simulation, wherein it is com- +mon for a small subset of solid elements to limit the time step size. With this +card the finely meshed parts (consisting of solid elements) can be made to run +with a smaller time step through mass scaling so that the rest of the vehicle can +run with a time step size of |DT2MS|. +Part Card. Additional card for the MASS_SCALED_PART and MASS_SCALED_- +PART_SET keyword options. Provide as many cards as necessary. Input ends at the +next keyword (“*”) card. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID/PSID +TS +Type +I +F +Default +none +none + VARIABLE +DESCRIPTION +PID/PSID +Part ID or part set ID if the SET option is specified. +TS +Time step size at which mass scaling is invoked for the PID or +PSID +Purpose: Stop the job. +*CONTROL_TERMINATION + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ENDTIM +ENDCYC +DTMIN +ENDENG ENDMAS NOSOL +Type +F +Default +0.0 +I +0 +F +F +F +0.0 +0.0 +1.0E+08 +I +0 +Remarks +1 +2 + VARIABLE +DESCRIPTION +ENDTIM +Termination time. Mandatory. +ENDCYC +DTMIN +ENDENG +ENDMAS +Termination cycle. The termination cycle is optional and will be +used if the specified cycle is reached before the termination time. +Cycle number is identical with the time step number. +Reduction (or scale) factor to determine minimum time step, +tsmin, where tsmin= dtstart× DTMIN and dtstart is the initial +step size determined by LS-DYNA. When the time step drops to +tsmin, LS-DYNA terminates with a restart dump. See the +exception described in Remark 2. +Percent change in energy ratio for termination of calculation. If +undefined, this option is inactive. +Percent change in the total mass for termination of calculation. +This option is relevant if and only if mass scaling is used to limit +the minimum time step size, see *CONTROL_TIMESTEP variable +name “DT2MS”. +NOSOL +Flag for a non-solution run, i.e. normal termination directly after +initialization. +EQ.0: off (default), +EQ.1: on. +Remarks: +1. Termination by displacement may be defined in the *TERMINATION section. +2. +If the erosion flag on *CONTROL_TIMESTEP is set (ERODE = 1), then solid +elements and thick shell elements whose time step falls below tsmin will be +eroded and the analysis will continue. This time-step-based failure option is +not recommended when solid formulations 11 or 12 are included in the model. +Furthermore, when PSFAIL in *CONTROL_SOLID is nonzero, regardless of the +value of ERODE, then all solid elements excepting those with formulation 11 or +12, whose time step falls below tsmin will be eroded and the analysis will con- +tinue. This time-step-based erosion of solids due to a nonzero PSFAIL is not +limited to solids in part set PSFAIL. Only the negative-volume-based erosion +criterion is limited to solids in part PSFAIL. +*CONTROL_THERMAL_EIGENVALUE +Purpose: Compute eigenvalues of thermal conductance matrix for model evaluation +purposes. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NEIG +Type +Default +I +0 +. +. + VARIABLE +DESCRIPTION +NEIG +Number of eigenvalues to compute. +EQ.0: No eigenvalues are computed. +GT.0: Compute NEIG eigenvalues of each thermal conductance +matrix. +Remarks: +1. Computes NEIG eigenvalues for each thermal conductance matrix. This is a +model evaluation tool and it is recommended that only a small number, such as +1, thermal time steps are used when using this feature. +*CONTROL_THERMAL_NONLINEAR +Purpose: Set parameters for a nonlinear thermal or coupled structural/thermal +analysis. The control card, *CONTROL_SOLUTION, is also required. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +REFMAX +TOL +DCP +LUMPBC +THLSTL +NLTHPR +PHCHPN +Type +I +F +F +Default +10 +1.e-04 1.0 or 0.5 +I +0 +F +0. +I +0 +F +100. + VARIABLE +DESCRIPTION +REFMAX +Maximum number of matrix reformations per time step: +EQ.0: set to 10 reformations. +TOL +Convergence tolerance for temperature: +EQ.0.0: set to 1000 * machine roundoff. +DCP +Divergence control parameter: +steady state problems 0.3 ≤ DCP ≤ 1.0 +0.0 < DCP ≤ 1.0 +transient problems +default 1.0 +default 0.5 +LUMPBC +Lump enclosure radiation boundary condition. LUMPBC = 1 +activates a numerical method +to damp out anomalous +temperature oscillations resulting from very large step function +boundary conditions. This option is not generally recommended. +EQ.0: off (default) +EQ.1: on +THLSTL +Line search convergence tolerance: +EQ.0.0: No line search +GT.0.0: Line search convergence tolerance +VARIABLE +DESCRIPTION +NLTHPR +Thermal nonlinear print out level: +EQ.0: No print out +EQ.1: Print convergence parameters during solution of +nonlinear system +PHCHPN +Phase change penalty parameter: +EQ.0.0: Set to default value 100. +GT.0.0: Penalty to enforce constant phase change temperature +*CONTROL +Purpose: Set options for the thermal solution in a thermal only or coupled structural- +thermal analysis. The control card, *CONTROL_SOLUTION, is also required. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ATYPE +PTYPE +SOLVER +CGTOL +GPT +EQHEAT +FWORK +SBC +Type +Default +I +0 +I +0 +I +F +3 +10-4/10-6 +I +8 +F +1. +F +1. +Remaining cards are optional.† + Card 2 +1 +2 +3 +4 +5 +6 +7 +Variable MSGLVL MAXITR +ABSTOL +RELTOL +OMEGA +Type +Default +I +0 +I +F +F +F +500 +10-10 +10-6 +1.0 or 0. +F +0. +8 +TSF +F +1. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable MXDMP +DTVF +VARDEN +Type +Default +I +0 +F +0. +I +0 +. +*CONTROL_THERMAL_SOLVER + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable MSGLVL NINNER +ABSTOL +RELTOL NOUTER +Type +Default +I +0 +I +F +F +I +100 +10-10 +10-6 +100 + VARIABLE +DESCRIPTION +ATYPE +Thermal analysis type: +EQ.0: Steady state analysis, +EQ.1: transient analysis. +PTYPE +Thermal problem type: +EQ.0: linear problem, +EQ.1: nonlinear problem with material properties evaluated at +gauss point temperature. +EQ.2: nonlinear problem with material properties evaluated at +element average temperature. +VARIABLE +DESCRIPTION +SOLVER +Thermal analysis solver type: +EQ.1: using solver 11 (enter -1 to use the old ACTCOL solver), +EQ.2: nonsymmetric direct solver, +EQ.3: diagonal scaled conjugate gradient iterative (default), +EQ.4: +incomplete choleski conjugate gradient iterative, +EQ.5: nonsymmetric diagonal scaled bi-conjugate gradient +EQ.11: symmetric direct solver +For MPP executables: +EQ.11: symmetric direct solver, +EQ.12: diagonal scaling (default for mpp) conjugate gradient +iterative, +EQ.13: symmetric Gauss-Siedel conjugate gradient iterative, +EQ.14: SSOR conjugate gradient iterative, +EQ.15: ILDLT0 (incomplete factorization) conjugate gradient +iterative, +EQ.16: modified ILDLT0 (incomplete factorization) conjugate +gradient iterative. +For Conjugate Heat transfer problems: +EQ.17: GMRES solver. +CGTOL +Convergence tolerance for SOLVER = 3 and 4. +EQ.0.0: use default value 10−4 single or 10−6 double precision +GPT +Number of Gauss points to be used in the solid elements: +EQ.0.0: use default value 8, +EQ.1.0: one point quadrature is used. +EQHEAT +Mechanical equivalent of heat . +EQ.0.0: default value 1.0, +LT.0.0: designates a load curve number for EQHEAT versus +time. +FWORK +Fraction of mechanical work converted into heat. +EQ.0.0: use default value 1.0. +SBC +*CONTROL_THERMAL_SOLVER +DESCRIPTION +Stefan Boltzmann constant. +radiation surfaces, see *BOUNDARY_RADIATION_… + Value is used with enclosure +LT.0.0: use a smoothing algorithm when calculating view +factors to force the row sum = 1. +MSGLVL +Output message level (For SOLVER > 10) +EQ.0: no output (default), +EQ.1: summary information, +EQ.2: detailed information, use only for debugging. +MAXITR +Maximum number of iterations. For SOLVER > 11. +EQ.0: use default value 500, +ABSTOL +Absolute convergence tolerance. For SOLVER > 11. +EQ.0.0: use default value 10−10 +RELTOL +Relative +SOLVER > 11. +convergence +tolerance. + Replaces CGTOL +for +EQ.0.0: use default value 10−6 +OMEGA +Relaxation parameter omega for SOLVER 14 and 16. +TSF +EQ.0.0: use default value 1.0 for Solver 14, use default value 0.0 +for Solver 16. +Thermal Speedup Factor. This factor multiplies all thermal +parameters with units of time in the denominator (e.g., thermal +conductivity, convection heat transfer coefficients). It is used to +artificially time scale the problem. Its main use is in metal +stamping. If the velocity of the stamping punch is artificially +increased by 1000, then set TSF = 1000 to scale the thermal +parameters. +MXDMP +Matrix Dumping for SOLVER > 11 +EQ.0: No Dumping +GT.0: Dump using ASCII format every MXDMP time steps. +LT.0: Dump using binary format every |MXDMP| time steps. +DTVF +Time interval between view factor updates. +VARIABLE +VARDEN +DESCRIPTION +Variable thermal density. This parameter is only applicable for +solid elements in a coupled thermal-stress problem. Setting this +parameter will adjust the material thermal density in the thermal +solver to account for very large volume changes when using an +EOS or large coefficient of thermal expansion. + For most +applications, the default value, VARDEN = 0, should be used. +EQ.0: use constant density (default) +EQ.1: modify thermal density to account for volume change +when using an EOS. +EQ.2: modify thermal density to account for volume change +when using a large coefficient of expansion. +NINNER +Number of inner iterations for GMRES solve +NOUTER +Number of outer iterations for GMRES solve +Remarks: +1. Solver Availability in MPP. Solvers 1, 2, 3 and 4 are only for SMP environ- +ments. Solvers 11, 12, 13, 14, 15 and 16 are for SMP and MPP. +2. Recommended Direct Solver. Solver 11 is the preferred direct solver. Solver +11 uses sparse matrix storage and requires much less memory than Solver 1. +3. Direct vs. Iterative Solve. Use of a direct solver (e.g., SOLVER = 1, 2 or 11) is +usually less efficient than using an iterative solver (SOLVER = 3, 4, 12, 13, 14, 15 +or 16). Consider using a direct solver to get the model running and then switch +to an iterative solver to decrease execution time (particularly for large models). +Direct solvers should be used when experiencing slow or no convergence. +4. Transient Problems. For transient problems, diagonal scaling conjugate +gradient (SOLVER = 3 or 12) should be adequate. +5. Steady State Problems. For steady state problems, convergence may be slow +or unacceptable, so consider using direct solver (SOLVER = 1, 2 or 11) or a more +powerful preconditioner (SOLVER = 4, 13, 14, 15 or 16). +6. Solvers 13 & 14. Solver 13 (symmetric Gauss-Seidel) and solver 14 (SSOR) are +related. When OMEGA = 1, solver 14 is equivalent to solver 13. The optimal +omega value for SSOR is problem dependent but lies between 1 and 2. +7. Solvers 15 & 16. Solver 15 (incomplete LDLT0) and solver 16 (modified +incomplete LDLT0) are related. Both are no-fill factorizations that require one +extra n-vector of storage. The sparsity pattern of the preconditioner is exactly +the same as that of the thermal stiffness matrix. Solver 16 uses the relaxation +parameter OMEGA. The optimal OMEGA value is problem dependent, but lies +between 0 and 1. +8. Solver 17. The GMRES solver has been developed as an alternative to the +direct solvers in cases where the structural thermal problem is coupled with the +fluid thermal problem in a monolithic approach using the ICFD solver. A sig- +nificant gain of calculation time can be observed when the problem reaches 1M +elements. +9. Completion Conditions for Solvers 12 – 15. Solvers 12, 13, 14, 15 and 16 +terminate the iterative solution process when (1) the number of iterations ex- +ceeds MAXITR or (2) the 2-norm of the residual drops below +ABSTOL + RELTOL × 2-norm of the initial residual. +10. Debug Data. Solvers 11 and up have the ability to dump the thermal +conductance matrix and right-hand-side using the same formats as documented +under *CONTROL_IMPLICIT_SOLVER. If this option is used files beginning +with “T_”will be generated. +11. Unit Conversion Factor. EQHEAT is a unit conversion factor. EQHEAT +converts the mechanical unit for work into the thermal unit for energy accord- +ing to, +EQHEAT × [work] = [thermal energy] +However, it is recommended that a consistent set of units be used with +EQHEAT set to 1.0. For example when using SI, +[work] = 1Nm = [thermal energy] = 1J ⇒ EQHEAT = 1. +*CONTROL_THERMAL_TIMESTEP +Purpose: Set time step controls for the thermal solution in a thermal only or coupled +structural/thermal analysis. This card requires that the deck also include *CONTROL_- +SOLUTION, and, *CONTROL_THERMAL_SOLVER needed. + Card 1 +Variable +Type +Default +1 +TS +I +0 +2 +TIP +3 +4 +5 +6 +7 +8 +ITS +TMIN +TMAX +DTEMP +TSCP +LCTS +F +F +0.5 +none +F +- +F +- +F +F +1.0 +0.5 +I +0 + VARIABLE +DESCRIPTION +TS +Time step control: +EQ.0: fixed time step, +EQ.1: variable time step (may increase or decrease). +TIP +Time integration parameter: +EQ.0.0: set to 0.5 - Crank-Nicholson scheme, +EQ.1.0: fully implicit. +ITS +Initial thermal time step +TMIN +Minimum thermal time step: +EQ.0.0: set to structural explicit time step. +TMAX +Maximum thermal time step: +EQ.0.0: set to 100 * structural explicit time step. +DTEMP +Maximum temperature change in each time step above which the +thermal time step will be decreased: +EQ.0.0: set to a temperature change of 1.0. +TSCP +Time step control parameter. The thermal time step is decreased +by this factor if convergence is not obtained. 0. < TSCP < 1.0: +EQ.0.0: set to a factor of 0.5. +LCTS +*CONTROL_THERMAL_TIMESTEP +DESCRIPTION +LCTS designates a load curve number which defines data pairs of +(thermal time breakpoint, new time step). The time step will be +adjusted to hit the time breakpoints exactly. After the time +breakpoint, the time step will be set to the ‘new time step’ +ordinate value in the load curve. +*CONTROL +Purpose: Set structural time step size control using different options. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DTINIT +TSSFAC +ISDO +TSLIMT +DT2MS +LCTM +ERODE +MS1ST +Type +F +F +Default +- +0.9 or +0.67 +I +0 +F +F +0.0 +0.0 +I +0 +I +0 +I +0 +This card is optional. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DT2MSF DT2MSLC +IMSCL +RMSCL +Type +F +I +Default +not +used +not +used +I +0 +F +0.0 + VARIABLE +DESCRIPTION +DTINIT +Initial time step size: +EQ.0.0: LS-DYNA determines initial step size. +TSSFAC +Scale factor for computed time step (old name SCFT). See +Remark 1 below. (Default = 0.90; if high explosives are used, the +default is lowered to 0.67). +ISDO +*CONTROL_TIMESTEP +DESCRIPTION +Basis of time size calculation for 4-node shell elements. 3-node +shells use the shortest altitude for options 0,1 and the shortest +side for option 2. This option has no relevance to solid elements, +which use a length based on the element volume divided by the +largest surface area. +EQ.0: characteristic length is given by +area +min(longest side, longest diagonal ) +. +EQ.1: characteristic length is given by +area +longest diagonal +. +EQ.2: based on bar wave speed and, +max [shortest side, +area +min(longest side, longest diagonal ) +] . +WARNING: Option 2 can give a much larger time +step size that can lead to instabilities +in some applications, especially when +triangular elements are used. +EQ.3: This feature is currently unavailable. Time step size is +based on the maximum eigenvalue. This option is okay +for structural applications where the material sound +speed changes slowly. The cost related to determining +the maximum eigenvalue is significant, but the increase +in the time step size often allows for significantly shorter +run times without using mass scaling. +VARIABLE +TSLIMT +DESCRIPTION +Shell element minimum time step assignment, TSLIMT. When a +shell controls the time step, element material properties (moduli +not masses) will be modified such that the time step does not fall +below the assigned step size. This option is applicable only to +shell elements using material models: +*MAT_PLASTIC_KINEMATIC, +*MAT_POWER_LAW_PLASTICITY, +*MAT_STRAIN_RATE_DEPENDENT_PLASTICITY, +*MAT_PIECE-WISE_LINEAR_PLASTICITY. +WARNING: This so-called stiffness scaling option is +NOT recommended. The DT2MS op- +tion below applies to all materials and +element classes and is preferred. +If both TSLIMT and DT2MS below are active and if TSLIMT is +input as a positive number, then TSLIMT defaults to 10−18, +thereby disabling it. +If TSLIMT is negative and less than |DT2MS|, then |TSLIMT| is +applied prior to the mass being scaled. If |DT2MS| exceeds the +magnitude of TSLIMT, then TSLIMT is set to 10−18. +VARIABLE +DESCRIPTION +DT2MS +Time step size for mass scaled solutions. (Default = 0.0) +GT.0.0: Positive values are for quasi-static analyses or time +history analyses where the inertial effects are insignifi- +cant. +LT.0.0: TSSFAC × |DT2MS| is the minimum time step size +permitted and mass scaling is done if and only if it is +necessary to meet the Courant time step size criterion. +This option can be used in transient analyses if the +mass increases remain insignificant. See also the varia- +ble MS1ST below and the *CONTROL_TERMINA- +TION variable ENDMAS. +WARNING: +Superelements from, *ELEMENT_DI- +RECT_MATRIX_INPUT, are not mass +scaled; consequently, DT2MS does +not affect their time step size. In this +case an error termination will occur, +and DT2MS will need to be reset to a +smaller value. +LCTM +Load curve ID that limits the maximum time step size (optional). +This load curve defines the maximum time step size permitted +versus time. If the solution time exceeds the final time value +defined by the curve the computed step size is used. If the time +step size from the load curve is exactly zero, the computed time +step size is also used. +VARIABLE +DESCRIPTION +ERODE +Erosion flag for solids and thick shells. +EQ.0: Calculation will terminate if time step drops to tsmin +. +EQ.1: Solids and thick shells whose time step drops to tsmin + will erode, and SPH +particles whose time step drops to tsmin will be deac- +tivated. +ERODE = 1 and tsmin > 0 also invokes erosion of any solid +element whose volume becomes negative, thereby preventing +termination of the analysis due to negative volume. The effect of +ERODE = 1 on erosion due to negative volue is superceded by a +nonzero PSFAIL in *CONTROL_SOLID. PSFAIL serves to limit +solid erosion based on negative volume to solids in part set PS- +FAIL. +MS1ST +Option for mass scaling that applies when DT2MS < 0. +EQ.0: (Default) Mass scaling is considered throughout the +analysis to ensure that the minimum time step cannot +drop below TSSFAC × |DT2MS|. Added mass may in- +crease with time, but it will never decrease. +EQ.1: Added mass is calculated at the first time step and +remains unchanged thereafter. The initial time step will +not be less than TSSFAC × |DT2MS|, but the time step +may subsequently decrease, depending on how the mesh +deforms and the element characteristic lengths change. +DT2MSF +Reduction (or scale) factor for initial time step size to determine +the minimum time step size permitted. Mass scaling is done if it +is necessary to meet the Courant time step size criterion. If this +option is used, DT2MS effectively becomes –DT2MSF multiplied +by the initial time step size, Δ𝑡, before Δ𝑡 is scaled by TSSFAC. +This option is active if and only if DT2MS = 0 above. +DT2MSLC +*CONTROL_TIMESTEP +DESCRIPTION +Load curve for determining the magnitude of DT2MS as a +function of time, 𝑓DT2MS(𝑡), during the explicit solutions phase. +Time zero must be in the abscissa range of this curve and the +ordinate values should all be positive. At a given simulation time +𝑡, 𝑓DT2MS(𝑡) × sign(DT2MS) plays the role of DT2MS according to +the description for DT2MS above. It is allowed to use all negative +ordinate values in the curve, then 𝑓DT2MS(𝑡) itself (sign and +magnitude) determines how mass scaling is performed and +DT2MS is neglected. It is however not allowed for the ordinate +values to change sign during the simulation. +IMSCL +Flag for selective mass scaling if and only if mass scaling active. +Selective mass scaling does not scale the rigid body mass and is +therefore more accurate. Since it is memory and CPU intensive, it +should be applied only to small finely meshed parts. +EQ.0: no selective mass scaling. +EQ.1: all parts undergo selective mass scaling. +LT.0: recommended: +|IMSCL| is the part set ID of the parts +that undergo selective mass scaling; all other parts are +mass scaled the usual way. +RMSCL +Flag for using rotational option in selective mass scaling +EQ.0.: Only translational inertia are selectively mass scaled +NE.0.: Both translational and rotational inertia are selectively +mass scaled +Remarks: +During the solution we loop through the elements and determine a new time step size +by taking the minimum value over all elements. +Δ𝑡 𝑛+1 = TSSFAC × min{Δ𝑡1, Δ𝑡2, . . . , Δ𝑡𝑁} +where N is the number of elements. The time step size roughly corresponds to the +transient time of an acoustic wave through an element using the shortest characteristic +distance. For stability reasons the scale factor TSSFAC is typically set to a value of 0.90 +(default) or some smaller value. To decrease solution time we desire to use the largest +possible stable time step size. Values larger than .90 will often lead to instabilities. +Some comments follow: +1. Sound Speed and Element Size. The sound speed in steel and aluminum is +approximately 5mm per microsecond; therefore, if a steel structure is modeled +with element sizes of 5mm, the computed time step size would be 1 microsec- +ond. Elements made from materials with lower sound speeds, such as foams, +will give larger time step sizes. Avoid excessively small elements and be aware +of the effect of rotational inertia on the time step size in the Belytschko beam +element. Sound speeds differ for each material, for example, consider: +Air +Water +Steel +Titanium +Plexiglass +331 m/s +1478 +5240 +5220 +2598 +2. Use Rigid Bodies when Possible. It is recommended that stiff components be +modeled by using rigid bodies. Do not scale the Young’s modulus, as that can +substantially reduce the time step size. +3. Triangular Elements. The altitude of the triangular element should be used to +compute the time step size. Using the shortest side is okay only if the calcula- +tion is closely examined for possible instabilities. This is controlled by parame- +ter ISDO. +4. Selective Mass Scaling. In the explicit time integration context and in +contrast to conventional mass scaling, selective mass scaling (SMS) is a well +thought out scheme that not only reduces the number of simulation cycles but +that also does not significantly affect the dynamic response of the system under +consideration. The drawback is that a linear system of equations must be +solved in each time step for the accelerations. In this implementation a pre- +conditioned conjugate gradient method (PCG) is used. +An unfortunate consequence of this choice of solver is that the efficiency will +worsen when attempting large time steps since the condition number of the +assembled mass matrix increases with the added mass. Therefore caution +should be taken when choosing the desired time step size. For large models it +is also recommended to only use SMS on critical parts since it is otherwise like- +ly to slow down execution; the bottleneck being the solution step for the sys- +tem of linear system of equations. +While some constraints and boundary conditions available in LS-DYNA are not +supported for SMS they can be implemented upon request from a user. +A partial list of constraints and boundary conditions supported with SMS: +Pointwise nodal constraints in global and local directions +Prescribed motion in global and local directions +Adaptivity +Rigid walls +Deformable elements merged with rigid bodies +Constraint contacts and spotwelds +Beam release constraints +By default, only the translational dynamic properties are treated. This means +that only rigid body translation will be unaffected by the mass scaling imposed. +There is an option to also properly treat rigid body rotation in this way, this is +invoked by flagging the parameter RMSCL. A penalty in computational ex- +pense is incurred but the results could be improved if rotations are dominating +the simulation. +*CONTROL +Purpose: Specify the user units for the current keyword input deck. This does not +provide any mechanism for automatic conversion of units of any entry in the keyword +input deck. It is intended to be used for several purposes, but currently only for the +situation where an external database in another set of units will be loaded and used in +the simulation. In this case, *CONTROL_UNITS provides the information necessary to +convert the external data into internal units . +If the needed unit is not one of the predefined ones listed for use on the first card, then +the second optional card is used to define that unit. Any non-zero scales that are +entered on optional card 2 override what is specified on the first card. These scales are +given in terms of the default units on card 1. For instance, if 3600.0 is given in the +second 20 character field on the optional second card (TIME_SCALE), then ‘hour’ is the +time unit (3600 seconds). + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LENGTH +TIME +MASS +TEMP +Type +A +A +A +Default +m +sec +kg +A +K +Optional Card only used when a new unit needs to be defined: + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LENGTH_SCALE +TIME_SCALE +MASS_SCALE +Type +F +Default +1.0 +F +1.0 +F +1.0 +VARIABLE +DESCRIPTION +LENGTH +Length units: +EQ.m: meter (default) +EQ.mm: millimeter +EQ.cm: centimeter +EQ.in: +inch +EQ.ft: +foot +TIME +Time units: +EQ.sec: +EQ.ms: +second (default) +msec, millisec +EQ.micro_s: microsec +MASS +Mass units: +EQ.kg: +EQ.g: +EQ.mg: +EQ.lb: +kilogram (default) +gram +milligram +pound +EQ.slug: +pound × sec2/foot +EQ.slinch: +pound × sec2/inch +EQ.mtrc_ton: metric_ton +TEMP +Temperature units: +EQ.K: Kelvin (default) +EQ.C: Celsius +EQ.F: Fahrenheit +EQ.R: Rankine +LENGTH_ +SCALE +TIME_ +SCALE +MASS_ +SCALE +Number of meters in the length unit for the input deck +Number of seconds in the time unit for the input deck +Number of kilograms in the mass unit for the input deck +The Keyword options in this section in alphabetical order are: +*DAMPING_FREQUENCY_RANGE_{OPTION} +*DAMPING_GLOBAL +*DAMPING_PART_MASS +*DAMPING_PART_STIFFNESS +*DAMPING_RELATIVE +*DAMPING_FREQUENCY_RANGE_{OPTION} +Purpose: This feature provides approximately constant damping (i.e. frequency- +independent) over a range of frequencies. +Available OPTIONS are: + Applies damping to global motion +DEFORM Applies damping to element deformation + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CDAMP +FLOW +FHIGH +PSID +(blank) +PIDREL +IFLG +Type +F +F +F +Default +0.0 +0.0 +0.0 +I +0 +I +0 +I +0 + VARIABLE +DESCRIPTION +CDAMP +Damping in fraction of critical. +FLOW +FHIGH +PSID +PIDREL +Lowest frequency in range of interest (cycles per unit time, e.g. +Hz if time unit is seconds) +Highest frequency in range of interest (cycles per unit time, e.g. +Hz if time unit is seconds) +Part set ID. The requested damping is applied only to the parts in +the set. If PSID = 0, the damping is applied to all parts except +those referred to by other *DAMPING_FREQUENCY_RANGE +cards. +Optional part ID of rigid body. Damping is then applied to the +motion relative to the rigid body motion. This input does not +apply to the DEFORM option. +IFLG +Method used for internal calculation of damping constants: +EQ.0: Iterative (more accurate), +EQ.1: Approximate (same as R9 and previous versions). +Remarks: +This feature provides approximately constant damping (i.e. frequency-independent) +over a range of frequencies. 𝐹low < 𝐹 < 𝐹highIt is intended for small damping ratios +(e.g. < 0.05) and frequency ranges such that 𝐹high/𝐹low is in the range 10 to 300. The +drawback to this method of damping is that it reduces the dynamic stiffness of the +model, especially at low frequencies. +Where the model contains, for example, a rigid foundation or base, the effects of this +stiffness reduction can be ameliorated by using PIDREL. In this case, the damping +forces resist motion relative to the base, and are reacted onto the rigid part PIDREL. +“Relative motion” here means the difference between the velocity of the node being +damped, and the velocity of a point rigidly connected to PIDREL at the same +coordinates as the node being damped. +This effect is predictable: the natural frequencies of modes close to 𝐹low are reduced by +3% for a damping ratio of 0.01 and 𝐹high/𝐹low in the range 10-30. Near 𝐹high the error is +between zero and one third of the error at 𝐹low. Estimated frequency errors are shown +in the next table. +Damping +Ratio +0.01 +0.02 +0.04 +% error for Fhigh/Flow = +3 to 30 +30 to 300 +300 to 3000 +3% +6% +12% +4.5% +9% +18% +6% +12% +24% +It is recommended that the elastic stiffnesses in the model be increased slightly to +account for this, e.g. for 0.01 damping across a frequency range of 30 to 600Hz, the +average error across the frequency range is about 2%. Increase the stiffness by (1.02)2, +i.e. by 4%. +Starting from R10, an iterative method is used for the internal calculation of the +damping constants . The new method results in the actual damping +matching the user-input damping ratio CDAMP more closely across the frequency +range FLOW to FHIGH. As an example, for CDAMP = 0.01, FLOW = 1 Hz and +FHIGH = 30 Hz, the actual damping achieved by the previous approximate method +varied between 0.008 and 0.012 (different values at different frequencies), i.e. there +were errors of up to 20% of the target CDAMP. With the iterative algoritm, the errors +are reduced to 1% of the target CDAMP. +*DAMPING_FREQUENCY_RANGE +The DEFORM option applies damping to the element responses (unlike the standard +*DAMPING_FREQUENCY_RANGE which damps the global motion of the nodes). +Therefore, rigid body motion is not damped when the DEFORM keyword option is +used. For this reason, DEFORM is recommended over the standard option. The +damping is adjusted based on current tangent stiffness; this is believed to be more +appropriate for a nonlinear analysis, which could be over-damped if a strain-rate- +proportional or viscous damping scheme were used. +It works with the following element formulations: +• Solids – types -1, -2, 1, 2, 3, 4, 9, 10, 13, 15, 16, 17, 99 +• Beams – types 1, 2, 3, 4, 5, 9 (note: not type 6) +• Shells – types 1-5, 7-17, 20, 21, 23-27, 99 +• Discrete elements +The DEFORM option differs from the standard option in several ways: +Standard Damping vs. Deformation Damping +Characteristic +Property +Keyword Option + +DEFORM +Damping on +Node velocities +Element responses +Rigid body motion +Can be damped +Never damped +Natural frequencies +Reduced (by percentages +shown in the above table) +Increased (percentages shown +in the above table) +Recommended +compensation +Increase elastic stiffness +Reduce elastic stiffness +Effect on timestep +None +Small reduction applied +automatically, same +percentage as in the frequency +change +Element types +damped +All +See list above +Damping energy +output +Included in “system damping +energy” +Included in Internal Energy +only if RYLEN = 2 on *CON- +TROL_ENERGY +*DAMPING +Purpose: Define mass weighted nodal damping that applies globally to the nodes of +deformable bodies and to the mass center of the rigid bodies. For specification of mass +damping by part ID or part set ID, use *DAMPING_PART_MASS. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LCID +VALDMP +STX +STY +STZ +SRX +SRY +SRZ +Type +Default +Remarks +I +0 +1 + VARIABLE +LCID +F +F +F +F +F +F +F +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +2 +2 +2 +2 +2 +2 +DESCRIPTION +Load curve ID which specifies the system +damping constant vs. time: +EQ.0: a constant damping factor as defined by VALDMP is +used, +GT.0: system damping is given by load curve LCID (which +must be an integer). The damping force applied to each +node is 𝑓 = −𝑑(𝑡)𝑚𝑣, where 𝑑(𝑡) is defined by load curve +LCID. +VALDMP +System damping constant, Ds (this option is bypassed if the load +curve number defined above is non zero). +STX +STY +STZ +SRX +SRY +SRZ +Scale factor on global 𝑥 translational damping forces. +Scale factor on global 𝑦 translational damping forces. +Scale factor on global 𝑧 translational damping forces. +Scale factor on global 𝑥 rotational damping moments. +Scale factor on global 𝑦 rotational damping moments. +Scale factor on global 𝑧 rotational damping moments. +*DAMPING_GLOBAL +1. Restart. This keyword is also used for the restart, see *RESTART. +2. Defaults for Scale Factors. If STX = STY = STZ = SRX = SRY = SRZ = 0.0 in +the input above, all six values are defaulted to unity. +3. Damping Exceptions. Mass damping will not be applied to deformable nodes +with prescribed motion or to nodes tied with CONSTRAINED_NODE_SET. +4. Formulation. With mass proportional system damping the acceleration is +computed as: +𝐚𝑛 = 𝐌−1(𝐏𝑛 − 𝐅𝑛 − 𝐅damp +where, 𝐌 is the diagonal mass matrix, 𝐏𝐧 is the external load vector, 𝐅𝑛 is the +internal load vector, and 𝐅damp + is the force vector due to system damping. This +latter vector is defined as: +) +𝐅damp += 𝐷𝑠𝑚𝐯 +The best damping constant for the system is usually some value approaching +the critical damping factor for the lowest frequency mode of interest. +(𝐷𝑠)critical = 2𝜔min +The natural frequency 𝜔min (given in radians per unit time) is generally taken as +the fundamental frequency of the structure. This frequency can be determined +from an eigenvalue analysis or from an undamped transient analysis. Note that +this damping applies to both translational and rotational degrees of freedom. +Also note that mass proportional damping will damp rigid body motion as well +as vibration. +Energy dissipated by through mass weighted damping is reported as system +damping energy in the ASCII file glstat. This energy is computed whenever +system damping is active. +*DAMPING +OPTION specifies that a part set ID is given with the single option: + +SET +If not used a part ID is assumed. +Purpose: Define mass weighted damping by part ID. Parts may be either rigid or +deformable. In rigid bodies the damping forces and moments act at the center of mass. +This command may appear multiple times in an input deck but cannot be combined +with *DAMPING_GLOBAL. + Card 1 +1 +2 +Variable +PID/PSID +LCID +Type +Default +I +0 +I +0 +3 +SF +F +1.0 +4 +5 +6 +7 +8 +FLAG +I +0 +Scale Factor Card. Additional Card for FLAG = 1. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +STX +STY +STZ +SRX +SRY +SRZ +Type +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +PID/PSID +Part ID, see *PART or part set ID, see *SET_PART. +LCID +Load curve ID which specifies the +damping constant vs. time, applied to the part(s) specified in +PID/PSID. +VARIABLE +DESCRIPTION +Scale factor for load curve. This allows a simple modification of +the load curve values. +Set this flag to unity if the global components of the damping +forces require separate scale factors. +Scale factor on global 𝑥 translational damping forces. +Scale factor on global 𝑦 translational damping forces. +Scale factor on global 𝑧 translational damping forces. +Scale factor on global 𝑥 rotational damping moments. +Scale factor on global 𝑦 rotational damping moments. +Scale factor on global 𝑧 rotational damping moments. +SF +FLAG +STX +STY +STZ +SRX +SRY +SRZ +Remarks: +Mass weighted damping damps all motions including rigid body motions. For high +frequency oscillatory motion stiffness weighted damping may be preferred. With mass +proportional system damping the acceleration is computed as: +𝛂𝑛 = 𝐌−1(𝐏𝑛 − 𝐅𝑛 − 𝐅damp +where, 𝐌 is the diagonal mass matrix, 𝐏𝑛 is the external load vector, 𝐅𝑛 is the internal + is the force vector due to system damping. This latter vector is +load vector, and 𝐅damp +defined as: +) +𝐅damp += 𝐷𝑠𝑚𝝂 +The critical damping constant for the lowest frequency mode of interest is +𝐷𝑠 = 2𝜔min +where 𝜔min is that lowest frequency in units of radians per unit time. The damping +constant specified as the ordinate of curve LCID is typically less than the critical +damping constant. The damping is applied to both translational and rotational degrees +of freedom. The component scale factors can be used to limit which global components +see damping forces. +Energy dissipated by through mass weighted damping is reported as system damping +energy in the ASCII file glstat. This energy is computed whenever system damping is +active. +Mass damping will not be applied to deformable nodes with prescribed motion or to +nodes tied with CONSTRAINED_NODE_SET. +*DAMPING_PART_STIFFNESS_{OPTION} +OPTION specifies that a part set ID is given with the single option: + +SET +If the SET option is not used, a part ID goes in the first field of Card 1. +Purpose: Assign Rayleigh stiffness damping coefficient by part ID or part set ID. This +damping command does not apply to parts comprised of discrete elements (*ELE- +MENT_DISCRETE) or discrete beams (*ELEMENT_BEAM with ELFORM = 6). + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID/PSID +COEF +Type +I +F +Default +none +0.0 + VARIABLE +DESCRIPTION +PID/PSID +Part ID or part set ID . +COEF +Rayleigh damping coefficient. Two methods are now available: +LT.0.0: Rayleigh damping coefficient in units of time, set based +on a given frequency and applied uniformly to each el- +ement in the specified part or part set. See remarks be- +low. +EQ.0.0: Inactive. +GT.0.0: Rayleigh damping coefficient for stiffness weighted +damping. Values between 0.01 and 0.25 are recom- +mended. Higher values are strongly discouraged, and +values less than 0.01 may have little effect. The damp- +ing coefficient is uniquely defined for each element of +the part ID. +Remarks: +The damping matrix in Rayleigh damping is defined as: +𝐂 = 𝛼𝐌 + 𝛽𝐊 +where 𝐂, 𝐌, and 𝐊 are the damping, mass, and stiffness matrices, respectively. The +constants α. and β are the mass and stiffness proportional damping constants. The +mass proportional damping can be treated by system damping, see keywords: *DAMP- +ING_GLOBAL and DAMPING_PART_MASS. Transforming 𝐂 with the ith eigenvector +𝛟𝑖 gives: +𝛟𝑖 +T𝐂𝛟𝑖 = 𝛟𝑖 +T(𝛼𝐌 + 𝛽𝐊)𝛟𝑖 = 𝛼 + 𝛽𝜔𝑖 +2 = 2𝜔𝑖𝜉𝑖𝛿𝑖𝑗 +where 𝜔𝑖 is the ith frequency (radians/unit time) and 𝜉𝑖 is the corresponding modal +damping parameter. +Generally, the stiffness proportional damping is effective for high frequencies and is +orthogonal to rigid body motion. Mass proportional damping is more effective for low +frequencies and will damp rigid body motion. If a large value of the stiffness based +damping coefficient is used, it may be necessary to lower the time step size +significantly. This must be done manually by reducing the time step scale factor on the +*CONTROL_TIMESTEP control card. Since a good value of β is not easily identified, +the coefficient, COEF, is defined such that a value of .10 roughly corresponds to 10% +damping in the high frequency domain. +In LS-DYNA versions prior to 960 or if COEF is input as less than 0, the critical +damping coefficient is equal to 2 divided by 𝜔𝑖. For example, 10% of critical damping +in the ith mode corresponds to +𝛽 = +0.20 +𝜔𝑖 +and COEF would be input as -𝛽. Typically, this method of applying stiffness damping +is stable only if 𝛽 is significantly smaller than the explicit time step size. +Energy dissipated by Rayleigh damping is computed if and only if the flag, RYLEN, on +the control card, *CONTROL_ENERGY is set to 2. This energy is accumulated as +element internal energy and is included in the energy balance. In the glstat file this +energy will be lumped in with the internal energy. +NOTE: Type 2 beam elements are a special case in which COEF is internally scaled by +0.1. Thus there is a factor of 10 less damping than stated above. This applies to both +negative and positive values of COEF. +*DAMPING_RELATIVE +Purpose: Apply damping relative to the motion of a rigid body. For example, it could +damp the deformation of a rotating tire relative to the wheel without damping the +rotating motion. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CDAMP +FREQ +PIDRB +PSID +DV2 +LCID +Type +Default +F +0 +F +0 +F +0 +I +0 +F +0.0 +I +0 + VARIABLE +DESCRIPTION +CDAMP +Fraction of critical damping. +Frequency at which CDAMP is to apply (cycles per unit time, e.g. +Hz if time unit is seconds). +Part ID of rigid body, see *PART. Motion relative to this rigid +body will be damped. +Part set ID. The requested damping is applied only to the parts in +the set. +Optional constant for velocity-squared term. See remarks. +ID of curve that defines fraction of critical damping vs. time. +CDAMP will be ignored if LCID is non-zero. +FREQ +PIDRB +PSID +DV2 +LCID +Remarks: +1. This feature provides damping of vibrations for objects that are moving +through space. The vibrations are damped, but not the rigid body motion. This +is achieved by calculating the velocity of each node relative to that of a rigid +body, and applying a damping force proportional to that velocity. The forces +are reacted onto the rigid body such that overall momentum is conserved. It is +intended that the rigid body is embedded within the moving object. +2. Vibrations at frequencies below FREQ are damped by more than CDAMP, +while those at frequencies above FREQ are damped by less than CDAMP. It is +recommended that FREQ be set to the frequency of the lowest mode of vibra- +tion. +3. The damping force of each node is calculated as follows: + F = - (D . m . v) – (DV2 . m .v2). +Where: +D = 4π . CDAMP . FREQ +m = mass of the node +v = velocity of node relative to the velocity of a point on the rigid +body at the same coordinates as the node. +The database definitions are optional, but are necessary to obtain output files containing +results information. In this section the database keywords are defined in alphabetical +order: +*DATABASE_OPTION +*DATABASE_ALE +*DATABASE_ALE_MAT +*DATABASE_BINARY_OPTION +*DATABASE_BINARY_D3PROP +*DATABASE_CPM_SENSOR +*DATABASE_CROSS_SECTION_OPTION1_{OPTION2} +*DATABASE_EXTENT_OPTION +*DATABASE_FATXML +*DATABASE_FORMAT +*DATABASE_FREQUENCY_ASCII_OPTION +*DATABASE_FREQUENCY_BINARY_OPTION +*DATABASE_FSI +*DATABASE_FSI_SENSOR +*DATABASE_HISTORY_OPTION +*DATABASE_MASSOUT +*DATABASE_NODAL_FORCE_GROUP +*DATABASE_PROFILE +*DATABASE_PAP_OUTPUT +*DATABASE_PWP_FLOW +*DATABASE_PWP_OUTPUT +*DATABASE_RECOVER_NODE +*DATABASE_SPRING_FORWARD +*DATABASE_SUPERPLASTIC_FORMING +*DATABASE_TRACER +*DATABASE_TRACER_GENERATE +The ordering of the database definition cards in the input file is completely arbitrary. +*DATABASE +OPTION1 specifies the type of database. LS-DYNA will not create an ASCII database +unless the corresponding *DATABASE_OPTION1 card is included in the input deck. +OPTION1 may be any of the items in the following list: +ABSTAT Airbag statistics. +ATDOUT Automatic tiebreak damage statistics for *CONTACT_AUTOMAT- +IC_ONE_WAY_SURFACE_TO_SURFACE_TIEBREAK, OPTIONs 7, +9, 10, and 11 (only SMP at the moment). +AVSFLT AVS database. See *DATABASE_EXTENT_OPTION. +BEARING +*ELEMENT_BEARING force output. +BNDOUT +Boundary condition forces and energy +CURVOUT Output from *DEFINE_CURVE_FUNCTION. +DEFGEO Deformed geometry file. (Note that to output this file in Chrysler +format insert the following line in your .cshrc file: “setenv LSTC_ +DEFGEO chrysler”) The nasbdf file (NASTRAN Bulk Data) is creat- +ed whenever the DEFGEO file is requested. +DCFAIL +Failure function data for *MAT_SPOTWELD_DAIMLERCHRYSLER +DEFORC Discrete spring and damper element (*ELEMENT_DISCRETE) data. +If the user wishes to be selective about which discrete elements are +output in deforc, use *DATABASE_HISTORY_DISCRETE_OPTION +to select elements for output (but only if BEAM = 0 in *DATA- +BASE_BINARY_D3PLOT) or set PF = 1 in *ELEMENT_DISCRETE to +turn off output for particular elements; otherwise all discrete ele- +ments are output. +DEMASSFLOW Measure mass flow rate across defined plane and use together with +*DEFINE_DE_MASSFLOW_PLANE. +DISBOUT Discrete beam element, type 6, relative displacements, rotations, and +force resultants, all in the local coordinate system, which is also out- +put. Use with *DATABASE_HISTORY_BEAM. +ELOUT +Element data. See *DATABASE_HISTORY_OPTION. Also, see Card +3 of the *DATABASE_EXTENT_BINARY parameters INTOUT and +NODOUT. This latter option will output all integration point data or +extrapolated data to the connectivity nodes in a file call eloutdet. +GCEOUT Geometric contact entities. +GLSTAT Global data. Always obtained if ssstat file is activated. +H3OUT Hybrid III rigid body dummies. +JNTFORC +Joint force file +MATSUM Material energies. See Remarks 1 and 2 below. +MOVIE +MPGS +See MOVIE option of *DATABASE_EXTENT_OPTION. +See MPGS option of *DATABASE_EXTENT_OPTION. +NCFORC Nodal interface forces. See *CONTACT - Card 1 (SPR and MPR) +NODFOR Nodal force groups. See *DATABASE_NODAL_FORCE_GROUP. +NODOUT Nodal point data. See *DATABASE_HISTORY_NODE_OPTION. +PBSTAT +Particle blast data. See *PARTICLE_BLAST +PLLYOUT +Pulley element data for *ELEMENT_BEAM_PULLEY. +PRTUBE +Pressure tube data for *DEFINE_PRESSURE_TUBE. +RBDOUT Rigid body data. See Remark 2 below. +RCFORC Resultant interface forces. Output in a local coordinate system is +available, see *CONTACT, Optional Card C. +RWFORC Wall forces. +SBTOUT +Seat belt output file +SECFORC Cross section forces. See *DATABASE_CROSS_SECTION_OPTION. +SLEOUT +Sliding interface energy. See *CONTROL_ENERGY +SPCFORC +SPC reaction forces. +SPHOUT +SPH data. See *DATABASE_HISTORY_OPTION. +SSSTAT +Subsystem data. See *DATABASE_EXTENT_SSSTAT. +SWFORC Nodal constraint reaction forces (spot welds and rivets). +TPRINT +Thermal output from a coupled structural/thermal or thermal only +analysis. + Includes all nodes unless *DATABASE_HISTORY_- +NODE_OPTION is also provided in the keyword input. +TRHIST +Tracer particle history information. See *DATABASE_TRACER. +OPTION2, if it set, must be set to FILTER, and this can only be used when OPTION1 is +set to NCFORC. When set to FILTER the keyword requires an additional data card, see +Card 2 below. +To include global and subsystem mass and inertial properties in the glstat and ssstat +files add the keyword option MASS_PROPERTIES as show below. If this option is +active the current mass and inertia properties are output including the principle inertias +and their axes. Mass of deleted nodes and rigid bodies are not included in the +calculated properties. +GLSTAT_MASS_PROPERTIES +SSSTAT_MASS_PROPERTIES +This is an option for the glstat file to include +mass and inertial properties. +This is an option for the ssstat file to include +mass and inertial properties for the subsystems. + Card 1 +Variable +1 +DT +2 +3 +4 +5 +6 +7 +8 +BINARY +LCUR +IOOPT +OPTION1 OPTION2 OPTION3 OPTION4 +Type +F +I +I +I +F/I +Default +0. +1 or 2 +none +0. +0 +I +0 +I +0 +I +0 + VARIABLE +DT +DESCRIPTION +Time interval between outputs. If DT is zero, no output is +printed. +BINARY +Flag for binary output. See remarks under "Output Files and +Post-Processing" in Appendix O, “LS-DYNA MPP User Guide.” +EQ.1: ASCII file is written: +This is the default for shared +memory parallel (SMP) LS-DYNA executables. +EQ.2: Data written to a binary database “binout”, which +contains data that would otherwise be output to the +ASCII file. The ASCII file in this case is not created. This +is the default for MPP LS-DYNA executables. +EQ.3: ASCII file is written and the data is also written to the +binary database (NOTE: MPP LS-DYNA executables will +only produce the binary database). +Optional curve ID specifying time interval between dumps. Use +*DEFINE_CURVE to define the curve; abscissa is time and +ordinate is time interval between dumps. +Flag to govern behavior of the plot frequency load curve defined +by LCUR: +EQ.1: At the time each plot is generated, the load curve value is +added to the current time to determine the next plot +time.(this is the default behavior) +EQ.2: At the time each plot is generated, the next plot time, 𝑡, is +LCUR +IOOPT +VARIABLE +DESCRIPTION +computed so that +𝑡 = the current time + LCUR(𝑡) . +EQ.3: A plot is generated for each abscissa point in the load +curve definition. The actual value of the load curve is +ignored. +OPTION1 applies to either the bndout, nodout or elout files. For +the nodout file OPTION1 is a real variable that defines the time +interval between outputs for the high frequency file, nodouthf. If +OPTION1 is zero, no output is printed. Nodal points that are to +be output at a higher frequency are flagged using HFO in the +DATABASE_HISTORY_NODE_LOCAL input. +For the elout file OPTION1 is an integer variable that gives the +number of additional history variables written into the elout file +for each integration point in the solid elements. See Remark 7 +below for the elout file and Remark 9 for the bndout file. +OPTION2 applies to either the bndout, nodouthf or elout files. +For the nodouthf OPTION2 defines the binary file flag for the +high frequency nodouthf file. See BINARY above. +For the elout file OPTION2 is an integer variable that gives the +number of additional history variables written into the elout file +for each integration point in the shell elements. See Remark 7 +below for the elout file and Remark 9 for the bndout file. +OPTION3 applies to the bndout and elout files only. For the elout +file OPTION3 is an integer variable that gives the number of +additional history variables written into the elout file for each +integration point in the thick shell elements. See Remark 7 below +for the elout file and Remark 9 for the bndout file. +OPTION4 applies to the bndout and elout files only. For the elout +file OPTION4 is an integer variable that gives the number of +additional history variables written into the elout file for each +integration point in the beam elements. See Remark 7 below for +the elout file and Remark 9 for the bndout file. +OPTION1 +OPTION2 +OPTION3 +OPTION4 +The following Card 2 applies only to *DATABASE_NCFORC_FILTER + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RATE +CUTOFF WINDOW +TYPE +Type +F +F +F +Default +none +none +none +I +0 +0 +0 +0 +0 + VARIABLE +DESCRIPTION +RATE +Time interval 𝑇 between filter sampling. +CUTOFF +Frequency cut-off 𝐶 in Hz. +WINDOW +The width of the window 𝑊 in units of time for storing the single, +forward + filtering required for the TYPE = 2 filter option. +Increasing the width of the window will increase the memory +required for the analysis. A window that is too narrow will +reduce the amplitude of the filtered result significantly, and +values below 15 are not recommended for that reason. In general, +the results for the TYPE = 2 option are sensitive to the width of +the window and experimentation is required. +TYPE +Flag for filtering options. +EQ.0: No filtering (default). +EQ.1: Single pass, forward Butterworth filtering. +EQ.2: Two pass filtering over the specified time window. +Backward Butterworth filtering is applied to the forward +Butterworth results that have been stored. This option +improves the phase accuracy significantly at the expense +of memory. +The file names and corresponding unit numbers are: +Description +I/O Unit # File Name +Airbag statistics +43 +Automatic tiebreak damage 92 +ASCII database +Boundary conditions +44 +46 +abstat +atdout +avsflt +bndout (nodal forces and energies) +Description +I/O Unit # File Name +Smug animator database +Discrete elements +40 +36 +Discrete elements mass flow 219 +Discrete beam elements +215 +Element data +Contact entities +Global data +Joint forces +Material energies +MOVIE file family +MPGS file family +Nastran/BDF file +Nodal interface forces +Nodal force group +Nodal point data +Pulley element data +Pressure tube data +Rigid body data +Resultant interface forces +Rigidwall forces +Seat belts +Cross-section forces +Interface energies +SPC reaction forces +SPH element data +Subsystems statistics +Nodal constraint resultants +Thermal output +Tracer particles +34 +48 +35 +53 +37 +50 +50 +49 +38 +45 +33 +216 +421 +47 +39 +32 +52 +31 +51 +41 +68 +58 +42 +73 +70 +defgeo +deforc +demflow +disbout +elout +gceout +glstat +jntforc +matsum +moviennn.xxx where.nnn=001-999 +mpgsnnn.xxx where nnn = 001-999 +nasbdf +ncforc +nodfor +nodout +pllyout +prtube +rbdout +rcforc +rwforc +sbtout +secforc +sleout +spcforc +sphout +ssstat +swforc (spot welds/rivets) +tprint +trhist +Output Components for ASCII Files. +ABSTAT +BNDOUT +DCFAIL + x, y, z force + energies + moment (rigid bodies) +volume +pressure +internal energy +input mass flow rate +output mass flow rate +mass +temperature +density +failure function +normal term +bending term +shear term +weld area +effective strain rate +axial force +shear force +torsional moment +bending moment +DEFORC +x, y, z force +ELOUT +(t)Shells +xx, yy, zz stress +xy, yz, zx stress +plastic strain +xx, yy, zz strain† +xy, yz, zx strain† +Beams +axial force resultant +s shear resultant +t shear resultant +s moment resultant +t moment resultant +torsional resultant +Solids +xx, yy, zz stress +xy, yz, zx stress +effective stress +yield function +xx, yy, zz strain† +xy, yz, zx strain† +† Strains written for solids and for lower and upper integration points of shells +and tshells if STRFLG = 1 in *DATABASE_EXTENT_BINARY. +GCEOUT +x, y, z force +x, y, z moment +time step +kinetic energy +internal energy +sprint and damper energy +hourglass energy +system damping energy +sliding interface energy +eroded kinetic energy +eroded internal energy +eroded hourglass energy +added mass +GLSTAT +total energy +external work +total and initial energy +energy ratio without eroded energy +element & part ID controlling time step +global x, y, z velocity +time per zone cycle +joint internal energy +stonewall energy +rigid body stopper energy +percentage [mass] increase +JNTFORC +x, y, z force +x, y, z moment +MATSUM +kinetic energy +internal energy +hourglass energy +x, y, z momentum +x, y, z rigid body velocity +eroded internal energy +eroded kinetic energy +added mass +NCFORC +NODOUT +X force +Y force +Z force + x, y, z displacement + X, y, z velocity + X, y, z acceleration + X, y, z rotation + X, y, z rotational velocity + X, y, z rotation acceleration +NODFOR +X, y. z force +PRTUBE +cross section area +pressure +velocity +density +PLLYOUT +RBDOUT +RCFORC +adjacent beam IDs +slip +slip rate +resultant force +wrap angle + x, y, z displacement + x, y, z velocity + x, y, z acceleration +x, y, z force +Mass of nodes in contact +RWFORC +SECFORC +SLEOUT +normal +x, y, z force +x, y, z force +x, y, z moment +x, y, z center +area +resultant force +slave energy +master energy +frictional energy +SPCFORC +SWFORC +SPHOUT +x, y, z force +x, y, z moment + axial force + shear force +failure function + weld length +resultant moment +torsion +xx, yy, zz stress +xy, yz, zx stress +density +number of neighbors +xx, yy, zz strain +xy, yz, zx strain +half of smoothing length +plastic strain +particle active state +effective stress +temperature +xx,yy,zz strain rate +xy,yz,zx strain rate +SPH to SPH coupling +forces +Remarks: +1. Discrepancies Between “matsum” and “glstat” Output. The kinetic energy +quantities in the matsum and glstat files may differ slightly in values for several +reasons. First, the energy associated with added mass (from mass-scaling) is +included in the glstat calculation, but is not included in matsum. Secondly, the +energies are computed element by element in matsum for the deformable mate- +rials and, consequently, nodes which are merged with rigid bodies will also +have their kinetic energy included in the rigid body total. Furthermore, kinetic +energy is computed from nodal velocities in glstat and from element midpoint +velocities in matsum. +2. PRINT Keyword Option on *PART. The PRINT option in the part definition +allows some control over the extent of the data that is written into the matsum +and rbdout files. If the print option is used the variable PRBF can be defined +such that the following numbers take on the meanings: +EQ.0: default is taken from the keyword *CONTROL_OUTPUT, +EQ.1: write data into rbdout file only, +EQ.2: write data into matsum file only, +EQ.3: do not write data into rbdout and matsum. +Also see CONTROL_OUTPUT and PART_PRINT. +3. The Restart Feature. This keyword is also used in the restart phase, see +*RESTART. Thus, the output interval can be changed when restarting. +4. LS-PrePost. All information in the files except in AVSFLT, MOVIE, and MPGS +can also be plotted using LS-PrePost. Arbitrary cross plotting of results be- +tween ASCII files is easily handled. +5. The “rcforc” File. Resultant contact forces reported in rcforc are averaged over +the preceding output interval. +6. Spring and Damper Energy. “Spring and damper energy” reported in glstat +is a subset of “Internal energy”. The “Spring and damper energy” includes +internal energy of discrete elements, seatbelt elements, and that associated with +joint stiffness. +7. OPTIONn Field for “elout”. OPTION1, OPTION2, OPTION3, and OPTION4 +give the number of additional history variables output for the integrated solids, +shells, thick shells, and beams, respectively. Within this special option, each +integration point is printed with its corresponding history data. No integration +points are averaged. This is different than the default output where the stress +data within a shell ply of a fully integrated shell, for example, are averaged and +then written as output. The primary purpose of this database extension is to +allow the actual integration point stress data and history variable data to be +checked. There are no transformations applied to either the output stresses or +history data. +8. The Failure Function. The failure function reported to the DCFAIL database is +set to zero when the weld fails. If damage is active, then it is set to the negative +of the damage scale factor which goes from 1 to 0 as damage grows. +9. OPTIONn Field for “bndout”. For the bndout file, OPTION1 controls the +nodal force group output, OPTION2 controls the concentrated force output, +OPTION3 controls the pressure boundary condition output, and OPTION4 +controls the velocity/displacement/acceleration nodal boundary conditions. If +the value is 0 or left blank, the category is included (the default), and if it is 1, +the category is not included in the bndout file. +10. Contents of “glstat”. The glstat table above includes all items that may appear +in the glstat data. The items that are actually written depend on the contents of +the input deck. For example, hourglass energy appears only if HGEN = 2 in +*CONTROL_ENERGY and added mass only appears if DT2MS < 0 in *CON- +TROL_TIMESTEP. +11. Element ID Controlling the Time Step. The element ID controlling the time +step is included in the glstat data but is not read by LS-PrePost. If the element +ID is of interest to the user, the ASCII version of the glstat file can be opened +with a text editor. +12. The FILTER Option. The FILTER option uses a Butterworth filter for the +forward, single pass filtering and the backward, double pass filtering options. +The forward filtered output 𝑌(𝑛) at sampling interval 𝑛 is obtained from the +solution value 𝑋(𝑛) using the formula +𝑌(𝑛) = 𝑎0𝑋(𝑛) + 𝑎1𝑋(𝑛 − 1) + 𝑎2𝑋(𝑛 − 2) + 𝑏1𝑌(𝑛 − 1) + 𝑏2𝑌(𝑛 − 2) +where the coefficients are +𝜔𝑑 = 2𝜋 ( +0.6 +) 1.25 +𝜔𝑎 = tan(𝜔𝑎 𝑇/2) +2/(1 + √2𝜔𝑎 + 𝜔𝑎 +2) +𝑎0 = 𝜔𝑎 +𝑎1 = 2𝑎0 +𝑎2 = 𝑎0 +𝑏1 = 2(1 − 𝜔𝑎 +2)/(1 + √2𝜔𝑎 + 𝜔𝑎 +2) +𝑏2 = (−1 + √2𝜔𝑎 − 𝜔𝑎 +2)/(1 + √2𝜔𝑎 + 𝜔𝑎 +2) +The two previous solution values and filtered values at 𝑛 − 1 and 𝑛 − 2 are +stored. +Backward filtering improves the phase response of the filtered output. It is +performed according to the formula +𝑍(𝑛) = 𝑎0𝑌(𝑛) + 𝑎1𝑌(𝑛 + 1) + 𝑎2𝑌(𝑛 + 2) + 𝑏1𝑍(𝑛 + 1) + 𝑏2𝑍(𝑛 + 2) +where 𝑍(𝑛) is the backward filtered value at sample time 𝑛. This implies that +all the forward filtered values 𝑌(𝑛) are stored during the analysis, and that +would require a prohibitive amount of memory. To limit the amount of +memory required, the forward filtered values at stored for the time interval 𝑊, +where the number of stored states is 𝑊/𝑇, and the backward filtering is applied +starting at the last saved value of the forward filtered values. As the window +width increases, the filtered values approach the values that would be obtained +from storing all of the forward filtered values. +The results of the backward filtering are sensitive to the window width, and +experimentation with the width is necessary to obtain good results with the +minimum window width. A window width of at least 10 to 15 times the sam- +ple rate 𝑇 should be used as a starting point. Some applications may require a +window width that is much larger. The required window width decreases as +the cut-off frequency increases. Or, to put it another way, the window width +must be increased to make the filtered output smoother. +As an example, a random series of numbers between 0 and 1 was generated and +filtered at intervals of 0.1 milliseconds with cut-off frequencies from 60 Hz to +420 Hz. The reverse filtering was applied with various window widths to de- +termine how many forward filtered states must be saved to achieve fixed levels +of accuracy compared to complete reverse filtering from the last state to the first +state. The results are shown in the table below. Note that the error is calculated +only for the first state and the numbers being filtered are random. This example +should only be used as a very rough guide that indicates the overall trends and not as a +recommendation for specific problems. +Cut-off +Frequency +No. of States +50% Error +No. of States +25% Error +No. of States +10% Error +No. of States +5% Error +No. of States +1% Error +60 Hz +120 Hz +180 Hz +240 Hz +300 Hz +360 Hz +420 Hz +26 +13 +8 +6 +5 +5 +4 +33 +16 +10 +8 +6 +6 +5 +55 +30 +22 +17 +12 +10 +9 +68 +37 +26 +19 +15 +12 +10 +87 +44 +30 +23 +18 +16 +15 +*DATABASE +Purpose: For each ALE group (or material), this card controls the output for element +time-history variables (in a tabular format that can be plotted in LS-PrePost by using the +XYPlot button). + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DTOUT +SETID +Type +F +I +Default +none +none +Variable Cards. Optional cards that can be used to add more variables with the +volume fractions in the database (the volume fractions are always output). Include as +many cards as necessary. This input ends at the next keyword (“*”) card. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +VAR +VAR +VAR +VAR +VAR +VAR +VAR +VAR +Type +Default +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 + VARIABLE +DESCRIPTION +DTOUT +Time interval between the outputs +SETID +ALE element set ID. +If the model is 1D (*SECTION_ALE1D), the set should be +*SET_BEAM +If the model is 2D (*SECTION_ALE2D), the set should be +*SET_SHELL +If the model is 3D (*SECTION_SOLID), the set should be +*SET_SOLID +VARIABLE +DESCRIPTION +VAR +Variable rank in the following list: +EQ.1: xx-stress +EQ.2: yy-stress +EQ.3: zz-stress +EQ.4: xy-stress +EQ.5: yz-stress +EQ.6: zx-stress +EQ.7: plastic strain +EQ.8: +internal energy +EQ.9: bulk viscosity +EQ.10: previous volume +EQ.11: pressure +EQ.12: mass +EQ.13: volume +EQ.14: density +EQ.15: kinetic energy +If there is a blank column between 2 variable ranks, the list +between these 2 ranks is selected. For example, if the card is as +follows: +1, ,6 +The 6 stresses are added to the database. +Remarks: +1. The .xy files are created when the termination time is reached or if one of the +following switches (after pressing the keys Ctrl - C) stops the job: sw1, stop, +quit. During the run, they can be created with the switch sw2. +2. The .xy files are created by element. There is a curve by ALE group (or +material). A last curve can be added for volume averaged variables. +*DATABASE +Purpose: For each ALE group (or material), this card activates extra output for: +1. material volume: alematvol.xy, +2. material mass: alematmas.xy, +3. +internal energy: alematEint.xy, +4. kinetic energy: alematEkin.xy, +5. +and kinetic energy loss during the advection: alematEkinlos.xy. +These files are written in the “.xy” format, which LS-PrePost can plot with its “XYPlot” +button. +Card +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DTOUT +BOXLOW +BOXUP +Type +F +Default +none +I +0 +I +0 + VARIABLE +DESCRIPTION +DTOUT +Time interval between the outputs +BOXLOW, BOXUP +Range of *DEFINE_BOX ids. BOXLOW is the lower bound +for the range while BOXUP is the upper bound. The series +of volumes covered by the specified range of *DEFINE_BOX +determines the mesh regions for which ALE material data +are to be output. +Remarks: +The “.xy” files are created at termination or if one of the following switches (Ctrl-C) is +encountered: sw2, sw1, stop, quit. +*DATABASE_BINARY_OPTION1_OPTION2 +keyword +This +*DATABASE_EXTENT_BINARY. +used +is +to +request +binary +output. +See +also +Choices for OPTION1 are: +BLSTFOR +Blast pressure database. See also *LOAD_BLAST_ENHANCED and +Remark 3. +CPMFOR +Corpuscular Particle Method interface force database. see Remark 2. +D3DRLF +Dynamic relaxation database. +D3DUMP +D3PART +D3PLOT +D3PROP +D3THDT +Database for restarts. Define output frequency in cycles. +Database for subset of parts. See also *DATABASE_EXTENT_BI- +NARY and *DATABASE_EXTENT_D3PART. +Database for entire model. See also *DATABASE_EXTENT_BINA- +RY. +Database containing property data. See *DATABASE_BINARY_- +D3PROP. +Database containing time histories for subsets of elements and +nodes. See *DATABASE_HISTORY. This database includes no ge- +ometry. +DEMFOR +DEM interface force database. See Remark 5. +FSIFOR +FSILNK +RUNRSF +INTFOR +ALE interface force database. See Remark 1. +ALE interface linking database. See Remark 4. +Database for restarts. Define output frequency in cycles. +Contact interface database. Its file name must either be given using +the FILE option or on the execution line using "S=". Also see +*CONTACT variables SPR and MPR. +PBMFOR +Particle Blast Method interface force database. +D3CRACK +Option to control output interval for ASCII “aea_crack” file for the +Winfrith concrete model (*MAT_084/085). Oddly, this command +does not control the output of the binary crack database for the Win- +frith concrete model. The binary crack database is written when +“q=” appears on the execution line and its output interval is taken +from *DATABASE_BINARY_D3PLOT, It is used by LS-PrePost to- +gether with the D3PLOT database to display cracks in the deformed +Winfrith concrete materials. +OPTION2 only applies when OPTION1 is set to INTFOR and the only choice for +OPTION2 is FILE. *DATABASE_BINARY_INTFOR_FILE requires one extra line of +input that specifies the name of the intfor database. +The D3DUMP and the RUNRSF options create complete databases which are necessary +for restarts, see *RESTART. When RUNRSF is specified, the same file is overwritten +after each interval, an option allows a series of files to be overwritten in a cyclic order. +When D3DUMP is specified, a new restart file is created after each interva, thus a +“family” of files is created numbered sequentially, e.g., d3dump01, d3dump02, etc. The +default file names are runrsf and d3dump unless other names are specified on the +execution line, see the INTRODUCTION, EXECUTION SYNTAX. Since all data held in +memory is written into the restart files, these files can be quite large and care should be +taken with the d3dump files not to create too many. If *DATABASE_BINARY_D3PLOT +is not specified in the keyword deck then the output interval for d3plot is automatically +set to 1/20th the termination time. +The d3plot, d3part, d3drlf, and intfor databases contain histories of geometry and of +state variables. Thus using these databases, one can, e.g., animate deformed geometry +and plot time histories of element stresses and nodal displacements with LS-PrePost. +The d3thdt database contains no geometry but rather time history data for element +subsets as well as global information, see *DATABASE_HISTORY. This data can be +plotted with LS-PrePost. The intfor database does not have a default filename and one +must be specified by adding s=filename to the execution line. +Similarly, for the fsifor database, a unique filename must be specified on the execution +line with h=filename; see the INTRODUCTION, EXECUTION SYNTAX. The file +structure is such that each file contains the full geometry at the beginning, followed by +the analysis generated output data at the specified time intervals. +For the contents of the d3plot, d3part and d3thdt databases, see also the *DATABASE_- +EXTENT_BINARY definition. It is possible to restrict the information that is dumped +and consequently reduce the size of the databases. The contents of the d3thdt database +are also specified with the *DATABASE_HISTORY definition. It should also be noted +in particular that the databases can be considerably reduced for models with rigid +bodies containing many elements. +FILE Card: Provide this card only for *DATABASE_BINARY_INTFOR_FILE. +FILE Card +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +Default + VARIABLE +FNAME +FNAME +A80 +none +DESCRIPTION +Name of the database for the intfor data. S = filename on the +execution line will override FNAME. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable DT/CYCL LCDT/NR +BEAM +NPLTC +PSETID +CID +Type +Default +F +- +I +- +I +- +I +- +I +- +I +- +D3PLOT Card. Additional Card for D3PLOT option. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IOOPT +RATE +CUTOFF WINDOW +TYPE +PSET +Type +Default +I +0 +F +F +F +none +none +none +I +0 +I +VARIABLE +DT / CYL +NR +LCDT +DESCRIPTION +This field defines the time interval between output states, DT, for +all options except D3DUMP, RUNRSF, and D3DRLF. +For D3DUMP, RUNRSF, and D3DRLF options the first field +contains CYCL instead of DT. These databases are updated every +CYCL convergence checks during the explicit dynamic relaxation +phase. +Number of RUNning ReStart Files, runrsf, written in a cyclical +fashion. The default is 1, i.e., only one runrsf file is created and +the data therein is overwritten each time data is output. +Optional load curve ID specifying time interval between dumps. +This variable is only available for options D3PLOT, D3PART, +D3THDT, INTFOR and BLSTFOR. +VARIABLE +BEAM +NPLTC +CID +DESCRIPTION +Discrete element option flag (*DATABASE_BINARY_D3PLOT +only). +EQ.0: Discrete spring and damper elements are added to the +d3plot database where they are displayed as beam ele- +ments. The discrete elements’ global 𝑥, global 𝑦, global 𝑧 +and resultant forces (moments), and change in length +(rotation) are written to the database where LS-PrePost +(incorrectly) labels them as though they were beam +quantities, i.e., axial force, S-shear resultant, T-shear re- +sultant, etc. +EQ.1: No discrete spring, damper and seatbelt elements are +added to the d3plot database. This option is useful when +translating old LS-DYNA input decks to KEYWORD +input. In older input decks there is no requirement that +beam and spring elements have unique ID's, and beam +elements may be created for the spring and dampers +with identical ID's to existing beam elements causing a +fatal error. However, this option comes with some limi- +tations and, therefore, should be used with caution. +1. Contact interfaces which are based on part IDs +of seatbelt elements will not be properly gener- +ated if this option is used. +2. DEFORMABLE_TO_RIGID will not work if PID +refers to discrete, damper, or seatbelt elements. +EQ.2: Discrete spring and damper elements are added to the +d3plot database where they are displayed as beam ele- +ments (similar to option 0). In this option the element +resultant force is written to its first database position +allowing beam axial forces and spring resultant forces to +be plotted at the same time. This can be useful during +some post-processing applications. +This flag, set in *DATABASE_BINARY_D3PLOT, also affects the +display of discrete elements in several other databases such as +d3drlf, d3part. +DT = ENDTIME/NPLTC. Applies to D3PLOT and D3PART +options only. This overrides the DT specified in the first field. +Coordinate system ID for FSIFOR and FSILNK, see *DEFINE_CO- +ORDINATE_SYSTEM. +VARIABLE +PSETID +DESCRIPTION +Part set ID for D3PART and D3PLOT options only. See *SET_- +PART. Parts in PSETID will excluded in the d3plot database. +Onlyparts in PSETID are included in the d3part database. +IOOPT +This variable applies to the D3PLOT option only. Flag to govern +behavior of the plot frequency load curve defined by LCDT: +EQ.1: At the time each plot is generated, the load curve value is +added to the current time to determine the next plot time +(this is the default behavior). +EQ.2: At the time each plot is generated, the next plot time T is +computed so that T = the current time plus the load +curve value at time T. +EQ.3: A plot is generated for each abscissa point in the load +curve definition. The actual value of the load curve is +ignored. +RATE +Time interval 𝑇 between filter sampling. +CUTOFF +Frequency cut-off 𝐶 in Hz. +WINDOW +The width of the window 𝑊 in units of time for storing the single, +forward filtering required for the TYPE = 2 filter option. +Increasing the width of the window will increase the memory +required for the analysis. A window that is too narrow will +reduce the amplitude of the filtered result significantly, and +values below 15 are not recommended for that reason. In general, +the results for the TYPE = 2 option are sensitive to the width of +the window and experimentation is required. +TYPE +Flag for filtering options. +EQ.0: No filtering (default). +EQ.1: Single pass, forward Butterworth filtering. +EQ.2: Two pass filtering over the specified time window. +Backward Butterworth filtering is applied to the forward +Butterworth results that have been stored. This option +improves the phase accuracy significantly at the expense +of memory. +PSET +*DATABASE_BINARY +DESCRIPTION +Part set ID for filtering. If no set is specified, all parts are +included. For each element integration point in the d3plot file, 24 +words of memory are required in LS-DYNA for the single pass +filtering, and more for the two pass filtering. Specifying PSET is +recommended to minimize the memory requirements. +Remarks: +1. FSIFOR. *DATABASE_BINARY_FSIFOR only applies to models having +penalty-based coupling between Lagrangian and ALE materials (CTYPE=4 or 5 +in the coupling card, *CONSTRAINED_LAGRANGE_IN_SOLID). When +*DATABASE_FSI is defined, a few pieces of coupling information of some +Lagrangian surface entities interacting with the ALE materials may be output as +history parameters into a file called “dbfsi”. Coupling pressure is one of the +output variables. However, this coupling pressure is averaged over the whole +surface entity being monitored. To obtain coupling pressure contour plot as a +function of time over the coupled surface, a user can define the *DATABASE_- +BINARY_FSIFOR keyword. To use it, three things must be done: +a) The INTFORC parameter (*CONSTRAINED_LAGRANGE_IN_SOLID, 4th +row, 3rd column) must be turned ON (INTFORC = 1). +b) A *DATABASE_BINARY_FSIFOR card is defined controlling the output +interval. The time interval between output is defined by the parameter +DT in this card. +c) This interface force file is activated by executing LS-DYNA as follows: +lsdyna i=inputfilename.k ... h=interfaceforcefilename +LS-DYNA will then write out the segment coupling pressure and forces +to a binary interface force file for contour plotting over the whole simula- +tion interval. +To plot the binary data in this file, type: lsprepost interfaceforcefilename. +For example, when all 3 of the above actions are taken, and assuming +“h” is set to “fsifor”, then a series of “fsifor##” binary files are output for +contour plotting. To plot this, type “lsprepost fsifor” (without the dou- +ble quotes). +2. CPMFOR. + *DATABASE_BINARY_CPMFOR applies +to models using +*AIRBAG_PARTICLE feature which controls the output interval of CPM inter- +face force file. This interface force file is activated by executing LS-DYNA with +command line option (cpm=). +lsdyna i=inputfilename.k … cpm=interfaceforce_filename +CPM interface force file stores segment’s coupling pressure and forces. The +coupling pressure is averaged over each segment without considering the effect +of ambient pressure, 𝑃atm. +3. BLSTFOR. The BLSTFOR database is not available for two dimensional +axisymmetric analysis. +4. FSILNK. The *DATABASE_BINARY_FSILNK variant writes the selected +*CONSTRAINED_LAGRANGE_IN_SOLID interface’s segment pressure to the +fsilink file for the next analysis without ALE meshes. +lsdyna i=inputfilename.k … fsilink=filename +5. DEMFOR. *DATABASE_BINARY_DEMFOR applies to models using DEM +coupling option *DEFINE_DE_TO_SURFACE_COUPLING. This card will +control the output interval of DEM interface force file. This interface force file is +activated by LS-DYNA command line option (dem=). +lsdyna i=inputfilename.k … dem=interfaceforce_filename +DEM interface force file stores segment’s coupling pressure and forces. +6. PBMFOR. *DATABASE_BINARY_PBMFOR applies to models using *PARTI- +CLE_BLAST feature which controls the output interval of PBM interface force +file. This interface force file is activated by executing LS-DYNA with command +line option (pbm=). +lsdyna i=inputfilename.k … pbm=interfaceforce_filename +PBM interface force file stores segment’s coupling pressure and forces. +*DATABASE_BINARY +Purpose: This card causes LS-DYNA to add the part, material, equation of state, +section, and hourglass data to the first d3plot file or else write the data to a separate +database d3prop. Rigidwall data can also be included. LS-PrePost does not read the +additional data so use of this command is of dubious benefit. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IFILE +IMATL +IWALL +Type +Default +I +1 +I +0 +I +0 + VARIABLE +IFILE +DESCRIPTION +Specify file for d3prop output. (This can also be defined on the +command line by adding d3prop = 1 or d3prop = 2 which also +sets IMATL = IWALL = 1) +EQ.1: Output data at the end of the first d3plot file. +EQ.2: Output data to the file d3prop. +IMATL +Output *EOS, *HOURGLASS, *MAT, *PART and *SECTION data. +EQ.0: No +EQ.1: Yes +IWALL +Output *RIGIDWALL data. +EQ.0: No +EQ.1: Yes +. +*DATABASE +Purpose: This card activates an ASCII file “cpm_sensor”. Its input defines sensors’ +locations based on the positions of some Lagrangian segments. The output gives the +history of the velocity, temperature, density and pressure averaged on the number of +particles contained in the sensors. This card is activated only when the *AIRBAG_PAR- +TICLE card is used. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DT +BINARY +Type +F +I +Sensor Definition Cards. Each card defines one sensor. This card may be repeated to +define multiple sensors. Input stops when the next “*” Keyword is found. +6 +7 +8 + Card 2 +1 +2 +3 +4 +Variable +SEGID +OFFSET +R/LX +LEN/LY +Type +I +F +F +F +5 +LZ +F + VARIABLE +DESCRIPTION +DT +Output interval +BINARY +Flag for the binary file +EQ.1: ASCII file is written, +EQ.2: Data written to the binary file “binout”, +EQ.3: ASCII file is written and the data written to the binary +file “binout”. +SEGID +Segment set ID +OFFSET +Offset distance between the center of the sphere sensor and the +segment center. If it is positive, Or, the distance between the base +of the cylinder and the segment center while LENGTH is not +zero. it is on the side pointed to by the segment normal vector. +See remarks1 and 3. +R/LX +*DATABASE_CPM_SENSOR +DESCRIPTION +Radius(sphere)/length in local X direction(rectangular) of the +sensor. See remarks 2 and 3. +LEN/LY +Length(cylinder)/length in local Y direction(rectangular) of the +sensor. +LZ +Length in local Z direction(rectangular) of the sensor see remark 4 +Remarks: +1. Each segment has a sensor. The distance between the segment center and the +sensor center is defined by OFFSET (2nd parameter on the 2nd line) in the normal +direction defined by the segment. This distance is constant: the sensor moves +along with the segment. +2. The sensor is a sphere with a radius given by RADIUS (3rd parameter on the 2nd +line). +3. OFFSET should be larger than RADIUS to prevent the segment from cutting the +sphere. For cylindrical sensor, OFFSET is the distance from segment to the base +of the cylinder. +4. For rectangular sensor, OFFSET is the distance from reference segment to the +sensor. The sensor is defined using the segment’s coordinates system. The base +point is n1 and local X direction is along the vector n2 - n1. The local Z direc- +tion is the segment normal direction and local Y direction is constructed by +local X and Z directions. +5. The output parameters in the “cpm_sensor” file are: +velx +vely +velz +velr +temp +dens +pres + = x-velocity + = y-velocity + = z-velocity + = velocity + = + = density + = pressure +temperature +These values are averaged on the number of particles in the sensor. RADIUS +should be large enough to contain a reasonable number of particles for the +averages. +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|. +$ INPUT: +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|. +*DATABASE_CPM_SENSOR +0.01 +$ SEGSID OFFSET RADIUS LENGTH + 123 5.0 5.0 + 124 -0.2 0.1 + 125 0.7 0.6 1.0 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|.. +$ The segment set id: 123 has 1 segment. +$ The segment set id: 123 has 1 segment. +$ The segment set id: 123 has 11 segments. +$ Each segment has an ID defined in D3HSP +$ The D3HSP file looks like the following: +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|.. +Segments for sensor 1 + Sensor id n1 n2 n3 n4 + 1 3842 3843 3848 3847 + Segments for sensor 2 + Sensor id n1 n2 n3 n4 + 2 3947 3948 3953 3952 + Segments for sensor 3 + Sensor id n1 n2 n3 n4 + 3 3867 3868 2146 2145 + 4 3862 3863 3868 3867 + 5 3857 3858 3863 3862 + 6 3852 3853 3858 3857 + 7 3847 3848 3853 3852 + 8 3837 3838 3843 3842 + 9 3842 3843 3848 3847 + 10 3832 3833 3838 3837 + 11 3827 3828 3833 3832 + 12 3822 3823 3828 3827 + 13 1125 1126 3823 3822 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|.. +*DATABASE_CROSS_SECTION_OPTION1_{OPTION2} +Option 1 includes: +PLANE +SET +To define an ID and heading for the database cross section use the option: +ID +Purpose: Define a cross section for resultant forces written to ASCII file secforc. +1. For the PLANE option, a set of two cards is required for each cross section. +Then a cutting plane has to be defined, see Figure 14-1. +2. +If the SET option is used, just one card is needed which identifies a node set and +at least one element set. In this case the node set(s) defines the cross section, +and the forces from the elements belonging to the element set(s) are summed +up to calculate the section forces. Thus the element set(s) should include ele- +ments on only one side (not both sides) of the cross section. +The cross-section should cut through deformable elements only, not rigid bodies. +Cutting through master segments for deformable solid element spot welds can lead to +incorrect section forces since the constraint forces are not accounted for in the force and +moment summations. Beam element modeling of welds do not require any special +precautions. +ID Card. Additional card for ID keyword option. + Optional +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CSID +Type +I +HEADING +A70 +The heading is picked up by some of the peripheral LS-DYNA codes to aid in post- +processing. + VARIABLE +DESCRIPTION +CSID +Cross section ID. This must be a unique number. +HEADING +Cross section descriptor. It is suggested that unique descriptions +be used. +Plane Card 1. First additional card for PLANE keyword option. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PSID +XCT +YCT +ZCT +XCH +YCH +ZCH +RADIUS +Type +Default +I +0 +F +0. +F +0. +F +0. +F +0. +F +0. +F +0. +F +0. +Plane Card 2. Second additional card for PLANE keyword option. + Card 2 +1 +2 +3 +4 +5 +Variable +XHEV +YHEV +ZHEV +LENL +LENM +Type +F +Default +0. +F +0. +F +F +F +0. +infinity +infinity +global +6 +ID +I +7 +8 +ITYPE +I +0 +The set option requires that the equivalent of the automatically generated input by the +cutting plane capability be identified manually and defined in sets. All nodes in the +cross-section and their related elements that contribute to the cross-sectional force +resultants must be defined. +Set Card. Additional Card for the SET keyword option. + Card 1 +1 +2 +3 +4 +5 +6 +Variable +NSID +HSID +BSID +SSID +TSID +DSID +Type +I +I +Default +required +0 +I +0 +I +0 +I +0 +I +0 +7 +ID +I +global +8 +ITYPE +I +*DATABASE_CROSS_SECTION +Resultants are computed +on this plane +Origin of cutting plane +Figure 14-1. Definition of cutting plane for automatic definition of interface +for cross-sectional forces. The automatic definition does not check for springs +and dampers in the section. For best results the cutting plane should cleanly +pass through the middle of the elements, distributing them equally on either +side. Elements that intersect the edges of the cutting plane are deleted from the +the cross-section. + VARIABLE +DESCRIPTION +CSID +PSID +XCT +YCT +ZCT +XCH +Optional ID for cross section. If not specified cross section ID is +taken to be the cross section order in the input deck. +Part set ID. If zero all parts are included. +𝑥-coordinate of tail of any outward drawn normal vector, N, +originating on wall (tail) and terminating in space (head), see +Figure 14-1. +𝑦-coordinate of tail of normal vector, 𝐍. +𝑧-coordinate of tail of normal vector, 𝐍. +𝑥-coordinate of head of normal vector, 𝐍. +VARIABLE +DESCRIPTION +YCH +ZCH +RADIUS +𝑦-coordinate of head of normal vector, 𝐍. +𝑧-coordinate of head of normal vector, 𝐍. +Optional radius. If a radius is set (radius ≠ 0), then circular cut +plane centered at (XCT, YCT ,ZCT) of radius = RADIUS, with the +normal vector originating at (XCT, YCT, ZCT) and pointing +towards (XCH, YCH, ZCH) will be created. In this case the +variables XHEV, YHEV, ZHEV, LENL, and LENM, which are +defined on the 2nd card will be ignored. +XHEV +YHEV +ZHEV +LENL +𝑥-coordinate of head of edge vector, 𝐋. +𝑦-coordinate of head of edge vector, 𝐋. +𝑧-coordinate of head of edge vector, 𝐋. +Length of edge 𝑎, in 𝐋 direction. +LENM +Length of edge 𝑏, in 𝐌 direction. +NSID +HSID +BSID +SSID +TSID +DSID +ID +Nodal set ID, see *SET_NODE_OPTION. +Solid element set ID, see *SET_SOLID. +Beam element set ID, see *SET_BEAM. +Shell element set ID, see *SET_SHELL_OPTION. +Thick shell element set ID, see *SET_TSHELL. +Discrete element set ID, see *SET_DISCRETE. +Rigid body , accelerometer ID , or coordinate ID, +see *DEFINE_COORDINATE_NODES. The force resultants are +output in the updated local system of the rigid body or +accelerometer. For ITYPE = 2, the force resultants are output in +the updated local coordinate system if FLAG = 1 in *DEFINE_CO- +ORDINATE_NODES or if NID is nonzero in *DEFINE_COORDI- +NATE_VECTOR. +ITYPE +*DATABASE_CROSS_SECTION +DESCRIPTION +Flag that specifies whether ID above pertains to a rigid body, an +accelerometer, or a coordinate system. +EQ.0: rigid body, +EQ.1: accelerometer, +EQ.2: coordinate system. +Available options include: +*DATABASE +AVS +BINARY +D3PART +INTFOR +MOVIE +MPGS +SSSTAT +Purpose: Control to some extent the content of specific output databases. +The BINARY option of *DATABASE_EXTENT applies to the binary databases d3plot, +d3thdt, and d3part. In the case of the d3part database, variables set using the D3PART +option will override the corresponding variables of the BINARY option. See also +*DATABASE_BINARY_OPTION. +The AVS, MOVIE, and MPGS databases will be familiar to users that have a use for +those databases. +*DATABASE_EXTENT_AVS +This command controls content written to the avsflt database. See AVSFLT option to +*DATABASE card. +Varriable Cards. Define as many cards as needed. Input ends at next keyword (“*”) +card. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +VTYPE +COMP +Type +I +I + VARIABLE +DESCRIPTION +VTYPE +Variable type: +EQ.0: node, +EQ.1: brick, +EQ.2: beam, +EQ.3: shell, +EQ.4: thick shell. +Component +components from the following tables can be chosen: +the corresponding VTYPE, + For +ID. +integer +VTYPE.EQ.0: Table 10.1, +VTYPE.EQ.1: Table 10.2, +VTYPE.EQ.2: not supported, +VTYPE.EQ.3: Table 10.3, +VTYPE.EQ.4: not supported. +COMP +Remarks: +The AVS database consists of a title card, then a control card defining the number of +nodes, brick-like elements, beam elements, shell elements, and the number of nodal +vectors, NV, written for each output interval. The next NV lines consist of character +strings that describe the nodal vectors. Nodal coordinates and element connectivity +follow. For each state the solution time is written, followed by the data requested +below. The last word in the file is the number of states. We recommend creating this +file and examining its contents, since the organization is relatively transparent. +Table 14-2. Nodal Quantities +Component ID +Quantity +1 +2 +3 +x, y, z-displacements +x, y, z-velocities +x, y, z-accelerations +Table 14-3. Brick Element Quantities +Component ID +1 +2 +3 +4 +5 +6 +7 +Quantity +x-stress +y-stress +z-stress +xy-stress +yz-stress +zx-stress +effective plastic strain +Table 14-4. Shell and Thick Shell Element Quantities +Component ID +Quantity +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +11 +12 +13 +14 +15 +16 +17 +18 +19 +20 +21 +22 +23 +24 +25 +26 +27 +28 +29 +midsurface x-stress +midsurface y-stress +midsurface z-stress +midsurface xy-stress +midsurface yz-stress +midsurface xz-stress +midsurface effective plastic strain +inner surface x-stress +inner surface y-stress +inner surface z-stress +inner surface xy-stress +inner surface yz-stress +inner surface zx-stress +inner surface effective plastic strain +outer surface x-stress +outer surface y-stress +outer surface z-stress +outer surface xy-stress +outer surface yz-stress +outer surface zx-stress +outer surface effective plastic strain +bending moment-mxx (4-node shell) +bending moment-myy (4-node shell) +bending moment-mxy (4-node shell) +shear resultant-qxx (4-node shell) +shear resultant-qyy (4-node shell) +normal resultant-nxx (4-node shell) +normal resultant-nxx (4-node shell) +normal resultant-nxx (4-node shell) +Component ID +Quantity +30 +31 +32 +33 +34 +35 +36 +37 +38 +39 +40 +41 +42 +43 +44 +45 +46 +47 +48 +49 +50 +51 +52 +53 +54 +55 +56 +57 +58 +59 +thickness (4-node shell) +element dependent variable +element dependent variable +inner surface x-strain +inner surface y-strain +inner surface z-strain +inner surface xy-strain +inner surface yz-strain +inner surface zx-strain +outer surface x-strain +outer surface y-strain +outer surface z-strain +outer surface xy-strain +outer surface yz-strain +outer surface zx-strain +internal energy +midsurface effective stress +inner surface effective stress +outer surface effective stress +midsurface max. principal strain +through thickness strain +midsurface min. principal strain +lower surface effective strain +lower surface max. principal strain +through thickness strain +lower surface min. principal strain +lower surface effective strain +upper surface max. principal strain +through thickness strain +upper surface min. principal strain +Component ID +Quantity +60 +upper surface effective strain +Table 14-5. Beam Element Quantities +Component ID +Quantity +1 +2 +3 +4 +5 +6 +x-force resultant +y-force resultant +z-force resultant +x-moment resultant +y-moment resultant +z-moment resultant +*DATABASE_EXTENT_BINARY_{OPTION} +Purpose: Control to some extent the content of binary output databases d3plot, d3thdt, +and d3part. See also *DATABASE_BINARY_OPTION and *DATBASE_EXTENT_D3- +PART. The content of the binary output database intfor may be modified using *DATA- +BASE_EXTENT_INTFOR. The option COMP controls to the content of binary output +databases d3plot and d3eigv. When the option COMP is used, it will suppress most of +settings in *DATABASE_EXTENT_BINARY. +Available options include: + +COMP +If no option is specified, use the following cards: + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NEIPH +NEIPS +MAXINT +STRFLG +SIGFLG +EPSFLG +RLTFLG +ENGFLG +Type +Default +I +0 +I +0 +Remarks + Card 2 +1 +2 +I +3 +1 +3 +I +1 +I +1 +I +1 +I +1 +I +0 +10 +4 +5 +6 +7 +8 +Variable +CMPFLG +IEVERP +BEAMIP +DCOMP +SHGE +STSSZ +N3THDT +IALEMAT +Type +Default +I +0 +I +0 +Remarks +I +0 +2 +I +1 +I +1 +I +1 +I +2 +I +*DATABASE_EXTENT_BINARY + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable NINTSLD PKP_SEN +SCLP +HYDRO +MSSCL +THERM +INTOUT NODOUT +Type +Default +I +1 +I +0 +F +1.0 +I +0 +I +0 +I +0 +A +A +none +none +Remarks + Card 4 +1 +2 +3 +4 +5 +6 +4 +7 +4 +8 +Variable +DTDT +RESPLT +NEIPB +Type +Default +I +1 +I +0 +I +0 +For COMP option, use Card 1 below (no Cards 2-4) + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IGLB +IXYZ +IVEL +IACC +ISTRS +ISTRA +ISED +Type +Default +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +Remarks +VARIABLE +NEIPH +NEIPS +DESCRIPTION +Number of additional integration point history variables written to +the binary databases (d3plot, d3part, d3drlf) for solid elements and +SPH particles. The integration point data is written in the same +order that it is stored in memory-each material model has its own +history variables that are stored. For user defined materials it is +important to store the history data that is needed for plotting +before the data which is not of interest. See also *DEFINE_MATE- +RIAL_HISTORIES. For output of additional integration point +history variables for solid elements to the elout database, see the +variable OPTION1 in *DATABASE_ELOUT. +Number of additional integration point history variables written to +the binary databases (d3plot, d3part, d3drlf) for both shell and +thick shell elements for each integration point, see NEIPH above +and *DEFINE_MATERIAL_HISTORIES. For output of additional +integration point history variables for shell and thick shell +elements to the elout database, see the variables OPTION2 and +OPTION3, respectively, in *DATABASE_ELOUT. +VARIABLE +MAXINT +DESCRIPTION +Number of shell and thick shell through-thickness integration +points for which output is written to d3plot. This does not apply +to strain tensor output flagged by STRFLG. +MAXINT +(def = 3) +number of +Integration +Points +Description +> 3 +(even & odd) +results are output for the outermost +(top) +(bottom) +and +integration points +together with +results for the neutral axis. +innermost +1 +All three results are identical. +3 +3 + > 3 +≤ MAXINT +≠ 3 +Even +< 0 +Any +for +the +Results +first MAXINT +integration points in the element will +be output. +See above. This will exclude mid- +results, whereas when +surface +MAXINT = 3 mid-surface results are +calculated and reported. +integration points are +MAXINT +output for each in plane integration +point location and no averaging is +used. This can greatly increase the +size of the binary databases d3plot, +d3thdt, and d3part. +See Remark 1 for more information. +VARIABLE +DESCRIPTION +STRFLG +STRFLG is interpreted digit-wise STRFLG = [𝑁𝑀𝐿], +STRFLG = 𝐿 + 𝑀 × 10 + 𝑁 × 100 +L.EQ.1: Write strain tensor data to d3plot and elout. For shell +and thick shell elements two tensors are written, one at +the innermost and one at the outermost integration +point. For solid elements a single strain tensor is writ- +ten. +M.EQ.1: Write plastic strain data to d3plot. +N.EQ.1: Write thermal strain data to d3plot. +Examples. For STRFLG = 11 (011) LS-DYNA will write both strain +and plastic strain tensors, but no thermal strain tensors. Whereas +for STRFLG = 110, LS-DYNA will write plastic and thermal strain +tensors but no strain tensors. For more information and supported +elements and materials, see Remark 10. +SIGFLG +Flag for including the stress tensor for shells and solids. +EQ.1: include (default), +EQ.2: exclude for shells, include for solids. +EQ.3: exclude for shells and solids. +EPSFLG +Flag for including the effective plastic strains for shells and solids. +EQ.1: include (default), +EQ.2: exclude for shells, include for solids. +EQ.3: exclude for shells and solids. +RLTFLG +Flag for including stress resultants in the shell LS-DYNA database: +EQ.1: include (default), +EQ.2: exclude. +ENGFLG +Flag for including shell internal energy density and shell thickness. +EQ.1: include (default), +EQ.2: exclude. +CMPFLG +*DATABASE_EXTENT_BINARY +DESCRIPTION +Flag to indicate the coordinate system for output of stress and +strain in solids, shells and thick shells comprised of orthotropic or +anisotropic materials. See Remark 4. +EQ.-1: Same as 1, but for *MAT_FABRIC (forms 14 and -14) and +*MAT_FABRIC_MAP the stress and strain is in engineer- +ing quantities instead of Green-Lagrange strain and 2nd +Piola-Kirchhoff stress. +EQ.0: global coordinate system with exception of elout for +shells . +EQ.1: local material coordinate system (as defined by AOPT +and associated parameters in the *MAT input, and if ap- +plicable, by angles B1, B2, etc. in *SECTION_SHELL, +*SECTION_TSHELL, or *PART_COMPOSITE, and by +optional input in the *ELEMENT data). CMPFLG = 1 +affects both d3plot and elout databases. +IEVERP +Every output state for the d3plot database is written to a separate +file. +EQ.0: more than one state can be on each plot file, +EQ.1: one state only on each plot file. +BEAMIP +Number of beam integration points for output. This option does +not apply to beams that use a resultant formulation. See Remark +2. +VARIABLE +DESCRIPTION +DCOMP +Data compression to eliminate rigid body data: +EQ.1: off (default), no rigid body data compression, +EQ.2: on, rigid body data compression active, +EQ.3: off, no rigid body data compression, but all nodal +velocities and accelerations are eliminated from the data- +base. +EQ.4: on, rigid body data compression active and all nodal +velocities and accelerations are eliminated from the data- +base. +EQ.5: on, rigid body data compression active and rigid nodal +data are eliminated from the database. Only 6 DOF rigid +body motion is written. +EQ.6: on, rigid body data compression active, rigid nodal data, +and all nodal velocities and accelerations are eliminated +from the database. Only 6 DOF rigid body motion is writ- +ten. +SHGE +Flag for including shell hourglass energy density. +EQ.1: off (default), no hourglass energy written, +EQ.2: on. +STSSZ +Flag for including shell element time step, mass, or added mass. +EQ.1: off (default), +EQ.2: output time step size, +EQ.3: output mass, added mass, or time step size. +See Remark 3 below. +N3THDT +Flag for including material energy in d3thdt database. +EQ.1: off, energy is NOT written to d3thdt database, +EQ.2: on (default), energy is written to d3thdt database. +IALEMAT +Output solid part ID list containing ALE materials. +EQ.1: on (default) +NINTSLD +PKP_SEN +SCLP +HYDRO +*DATABASE_EXTENT_BINARY +DESCRIPTION +Number of solid element integration points written to the LS- +DYNA database. When NINTSLD is set to 1 (default) or to any +value other than 8, integration point values are averaged and only +those averages are written output. To obtain values for individual +integration points, set NINTSLD to 8, even if the multi-integration +point solid has fewer than 8 integration points. +Flag to output the peak pressure and surface energy computed by +each contact interface into the interface force database. To obtain +the surface energy, FRCENG, must be sent to 1 on the control +contact card. When PKP_SEN = 1, it is possible to identify the +energies generated on the upper and lower shell surfaces, which is +important in metal forming applications. This data is mapped +after each H-adaptive remeshing. +EQ.0: No data is written +EQ.1: Output the peak pressures and surface energy by contact +interface +A scaling parameter used in the computation of the peak pressure. +This parameter is generally set to unity (the default), but it must be +greater than 0. +Either 3, 5 or 7 additional history variables useful to shock physics +are output as the last history variables to d3plot (does not apply to +elout). For HYDRO = 1, the internal energy per reference volume, +the reference volume, and the pressure from bulk viscosity are +added to the database, and for HYDRO = 2, the relative volume +and current density are also added. For HYDRO = 4, two further +variables are added: volumetric strain (defined as relative volume +– 1.0), and Hourglass energy per unit initial volume. +MSSCL +Output nodal information related to mass scaling into the d3plot +database. This option can be activated if and only if DT2MS < 0.0, +see control card *CONTROL_TIMESTEP. +EQ.0: No data is written +EQ.1: Output incremental nodal mass +EQ.2: Output percentage increase in nodal mass +See Remark 3. +VARIABLE +THERM +DESCRIPTION +Output of thermal data to d3plot. The use of this option +(THERM > 0) may make the database incompatible with other 3rd +party software. +EQ.0: (default) output temperature +EQ.1: output temperature +EQ.2: output temperature and flux +EQ.3: output temperature, flux, and shell bottom and top +surface temperature +INTOUT +Output stress/strain at all integration points for detailed element +output in the ASCII file eloutdet. DT and BINARY of *DATA- +BASE_ELOUT apply to eloutdet. See Remark 4. +EQ.STRESS: when stress output is required +EQ.STRAIN: when strain output is required +EQ.ALL: +when both stress and strain output are required +NODOUT +Output extrapolated stress/strain at connectivity nodes for +detailed element output in the ASCII file eloutdet. DT and BINA- +RY of *DATABASE_ELOUT apply to eloutdet. See Remark 4. +EQ.STRESS: +when stress output is required +EQ.STRAIN: +when strain output is required +EQ.ALL: +when both stress and strain output are +required +EQ.STRESS_GL: when nodal averaged stress output along the +global coordinate system is required +EQ.STRAIN_GL: when nodal averaged strain output along the +global coordinate system is required +EQ.ALL_GL: +for global nodal averaged stress and strain +output +DTDT +Output of node point Δtemperature/Δtime data to d3plot. +EQ.0: (default) no output +EQ.1: output Δ𝑇/Δ𝑡 +RESPLT +*DATABASE_EXTENT_BINARY +DESCRIPTION +Output of translational and rotational residual forces to d3plot and +d3iter. +EQ.0: No output +EQ.1: Output residual +NEIPB +Number of additional element or integration point history +variables written to the binary databases (d3plot, d3part, d3drlf) +for beam elements, see NEIPH above, BEAMIP and *DEFINE_MA- +TERIAL_HISTORIES. + For output of +additional integration point history variables for beam elements to +the elout database, see the variable OPTION4 in *DATABASE_- +ELOUT. + See also Remark 12. +IGLB +Output flag for global data +EQ.0: no +EQ.1: yes +IXYZ +Output flag for geometry data +EQ.0: no +EQ.1: yes +IVEL +Output flag for velocity data +EQ.0: no +EQ.1: yes +IACC +Output flag for acceleration data +EQ.0: no +EQ.1: yes +ISTRS +Output flag for stress data +EQ.0: no +EQ.1: yes +ISTRA +Output flag for strain data +EQ.0: no +EQ.1: yes +ISED +Output flag for strain energy density data +EQ.0: no +EQ.1: yes +Remarks: +1. MAXINT Field. If MAXINT is set to 3 then mid-surface, inner-surface and +outer-surface stresses are output at the center of the element. For an even num- +ber of integration points, the points closest to the center are averaged to obtain +the midsurface values. If multiple integration points are used in the shell plane, +the stresses at the center of the element are found by computing the average of +these points. For MAXINT equal to 3, LS-DYNA assumes that the data for the +user defined integration rules are ordered from bottom to top even if this is not +the case. If MAXINT is not equal to 3, then the stresses at the center of the ele- +ment are output in the order that they are stored for the selected integration +rule. If multiple points are used in plane the stresses are first averaged. +2. BEAMIP Field. Beam stresses are output if and only if BEAMIP is greater than +zero. In this latter case the data that is output is written in the same order that +the integration points are defined. The data at each integration point consists of +the following five values for elastic-plastic Hughes-Liu beams: the normal +stress, 𝜎𝑟𝑟; the transverse shear stresses, σrs and σtr; the effective plastic strain, +and the axial strain which is logarithmic. For beams that are not elastic-plastic, +the first history variable, if any, is output instead of the plastic strain. For the +beam elements of Belytschko and his co-workers, the transverse shear stress +components are not used in the formulation. No data is output for the Be- +lytschko-Schwer resultant beam. +3. Mass Scaling. If mass scaling is active, the output of the time step size reveals +little information about the calculation. If global mass scaling is used for a +constant time step, the total element mass is output; however, if the mass is +increased so that a minimum time step size is maintained (DT2MS is negative), +the added mass is output. Also, see the control card *CONTROL_TIMESTEP. +4. Output Coordinate System. Output coordinate system used. When the +parameters: INTOUT or NODOUT is set to STRESS, STRAIN, or ALL, the out- +put coordinate system of the data, similar to the ASCII file elout, is determined +by CMPFLG in *DATABASE_EXTENT_BINARY. +a) When NODOUT is set to STRESS, STRAIN , or ALL. Each node of the el- +ement nodal connectivity will be output. See Example 1. +b) Nodal output when NODOUT is set to STRESS_GL, STRAIN_GL, or +ALL_GL. Averaged nodal results are calculated by summing up all con- +tributions from elements sharing the common node, and then dividing the +total by the number of contributing elements. Averaged nodal values are +always output in the global coordinate system. See Example 2. +5. Contents of eloutdet. Available stress/strain components in eloutdet stress +components includes 6 stress components (sig-𝑥𝑥, sig-𝑦𝑦, sig-𝑧𝑧, sig-𝑥𝑦, sig-𝑦𝑧, +sig-𝑧𝑥), yielding status, and effective plastic strain. Strain components includes +6 strain components +6. Shell Element Output at Integration Points. stresses at all integration points +can be output. The strain at the top and bottom integration layer can be output. +At a connective node the extrapolated stress and strain at the top and bottom +layer can be output +7. Thick Shells. Thick shell element output includes the six stress components at +each integration point. Strain at the top and bottom layer can be output. At +the element node, values at the bottom layer are extrapolated to yield the values +of nodes 1-4, and values at the top layer are extrapolated to yield values of +nodes 5-8. +8. +Integration Point Locations. Stresses and strain at all integration points can +be output. The integration point order is as follows: +a) point #1 is the point closest to node #1 in the connectivity array +b) point #2 is the closest point to node #2, etc +c) For tetrahedrons type 4, 16 and 17 with 5 integration points, point #5 is the +midpoint. +d) For the nodal points, values at the integration points are extrapolated. +9. Reporting Residual Forces and Moments. The output of residual forces and +moments is supported for implicit and double precision only. With this option +the forces and moments appear under the Ndv button in the fringe menu in LS- +PrePost. The residual for rigid bodies is distributed to the slave nodes for the +body without scaling for the purpose of capturing the complete residual vector. +10. Calculation of Strains (STRFLG). The strain tensor 𝜺 that are output to the +d3plot database are calculated using proper time integration of the rate-of- +deformation tensor 𝐃. More specifically, to assert objectivity of the resulting +strain, it is for solids using a Jaumann rate of strain whereas for shells it uses the +co-rotational strain rate. In mathematical terms the integration is using the +following strain rates +𝛆̇ = 𝐃 − 𝛆𝐖 + 𝐖𝛆 +(solids) +𝛆̇ = 𝐃 − 𝛆𝛀 + 𝛀𝛆 +(shells) +where 𝐖 is the spin tensor and 𝛀 = 𝐐̇ 𝐐T is the rotational velocity of the co- +rotational system 𝐐 used for the shell element in question, taking into account +invariant node numbering and such. This is to say that the resulting strains +would be equal to the Cauchy stress for a hypo-elastic material (MAT_ELAS- +TIC) with a Young’s modulus of 1 and a Poisson’s ratio of 0. This should be +kept in mind when interpreting the results since they are not invariant to +changes in element formulations and possibly nodal connectivities. +11. Plastic and Thermal Strain (STRFLG). The algorithm for writing plastic and +thermal strains, which is also activated using STRFLG, is a modification of the +algorithm used for mechanical strains . +a) For solids the element average strain in the global system having 6 com- +ponents is written (local system if CMPFLG is set). +b) For shells both plastic and thermal strains have 6 components. The ther- +mal strain is written as a single tensor as in the solid case. The plastic +strain output consists of 3 plane-averaged tensors: one for the bottom, one +for the middle, and one for the top. For an even number of through thick- +ness integration points, the middle is taken to be the average of the two in- +tegration points closest to the mid surface. Currently, only the following +element/materials combinations are supported but other will be added +upon request. +Thermal strain tensors +Plastic strain tensors +Shells +Solids Materials +Shells +Solids +Materials +2, 16, 23 +1, 2 +Add +thermal +expansion, +255 +2, 16, 23 +1, 2 +24, 255 +12. History Variables for Beams (NEIPB). In general, NEIPB follows the same +conventions as NEIPH and NEIPS do for solid and shell elements and is sup- +ported in LS-PrePost v4.3 or later. Average, min and max values for each ele- +ment are output, including data for resultant elements. If BEAMIP is nonzero, +then element data is complemented with BEAMIP integration point values that +can be examined individually. Beam history data is post-processed similarly to +that of solid and shell element history data. +Example 1: +Excerpt from eloutdet file for a shell element with two through-thickness integration +points and four in-plane integration points, with INTOUT = STRESS and NO- +DOUT = STRESS: +element materl + ipt stress sig-xx sig-yy sig-zz sig-xy sig0yz sig-zx yield location + 1- 1 + 1- 10 elastic 4.41E-2 2.51E-1 0.00E+0 7.76E-8 0.00E+0 0.00E+0 0.00E+0 int. point 1 + 1- 10 elastic 4.41E-2 2.51E-1 0.00E+0 7.76E-8 0.00E+0 0.00E+0 0.00E+0 int. point 2 + 1- 10 elastic 4.41E-2 2.51E-1 0.00E+0 7.76E-8 0.00E+0 0.00E+0 0.00E+0 int. point 3 + 1- 10 elastic 4.41E-2 2.51E-1 0.00E+0 7.76E-8 0.00E+0 0.00E+0 0.00E+0 int. point 4 + 1- 10 elastic 4.41E-2 2.51E-1 0.00E+0 7.76E-8 0.00E+0 0.00E+0 0.00E+0 node 21 +1- 10 elastic 4.41E-2 2.51E-1 0.00E+0 7.76E-8 0.00E+0 0.00E+0 0.00E+0 node 22 + 1- 10 elastic 4.41E-2 2.51E-1 0.00E+0 7.76E-8 0.00E+0 0.00E+0 0.00E+0 node 20 + 1- 10 elastic 4.41E-2 2.51E-1 0.00E+0 7.76E-8 0.00E+0 0.00E+0 0.00E+0 node 19 + 2- 10 elastic 4.41E-2 2.51E-1 0.00E+0 7.76E-8 0.00E+0 0.00E+0 0.00E+0 int. point 1 + 2- 10 elastic 4.41E-2 2.51E-1 0.00E+0 7.76E-8 0.00E+0 0.00E+0 0.00E+0 int. point 2 + 2- 10 elastic 4.41E-2 2.51E-1 0.00E+0 7.76E-8 0.00E+0 0.00E+0 0.00E+0 int. point 3 + 2- 10 elastic 4.41E-2 2.51E-1 0.00E+0 7.76E-8 0.00E+0 0.00E+0 0.00E+0 int. point 4 + 2- 10 elastic 4.41E-2 2.51E-1 0.00E+0 7.76E-8 0.00E+0 0.00E+0 0.00E+0 node 21 + 2- 10 elastic 4.41E-2 2.51E-1 0.00E+0 7.76E-8 0.00E+0 0.00E+0 0.00E+0 node 22 + 2- 10 elastic 4.41E-2 2.51E-1 0.00E+0 7.76E-8 0.00E+0 0.00E+0 0.00E+0 node 20 + 2- 10 elastic 4.41E-2 2.51E-1 0.00E+0 7.76E-8 0.00E+0 0.00E+0 0.00E+0 node 19 +Example 2: +Excerpt from eloutdet file for averaged nodal strain: +nodal strain calculations for time step 24 (at time 9.89479E+01 ) + node (global) + strain eps-xx eps-yy eps-zz eps-xy eps-yz eps-zx + 1- + lower surface 2.0262E-01 -2.6058E-02 -7.5669E-02 -5.1945E-03 0.0000E+00 0.0000E+00 + upper surface 2.0262E-01 -2.6058E-02 -7.5669E-02 -5.1945E-03 0.0000E+00 0.0000E+00 + 2- + lower surface 1.9347E-01 2.3728E-04 -8.3019E-02 -1.4484E-02 0.0000E+00 0.0000E+00 + upper surface 1.9347E-01 2.3728E-04 -8.3019E-02 -1.4484E-02 0.0000E+00 0.0000E+00 + 3- + lower surface 2.0541E-01 -5.7521E-02 -6.3383E-02 -1.7668E-03 0.0000E+00 0.0000E+00 + upper surface 2.0541E-01 -5.7521E-02 -6.3383E-02 -1.7668E-03 0.0000E+00 0.0000E+00 + ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ ⋮ +*DATABASE +The following cards control content to the d3part binary database (Card 3 is optional). +The parameters given here will supercede the corresponding parameters in *DATA- +BASE_EXTENT_BINARY when writing the d3part binary database. See also *DATA- +BASE_BINARY_D3PART which defines the output interval for d3part and the set of +part included in d3part. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NEIPH +NEIPS +MAXINT +STRFLG +SIGFLG +EPSFLG +RLTFLG +ENGFLG +Type +Default +I +0 +I +0 +Remarks + Card 2 +1 +2 +I +3 +1 +3 +I +0 +I +1 +I +1 +I +1 +I +1 +4 +5 +6 +7 +8 +Variable +IEVERP +SHGE +STSSZ +I +0 +5 +I +0 +6 +7 +8 +3 +4 +I +0 +2 +Type +Default + Card 3 +1 +Variable NINTSLD +Type +Default +I +NEIPH +NEIPS +MAXINT +STRFLG +*DATABASE_EXTENT_D3PART +DESCRIPTION +Number of additional integration point history variables written +to the binary database for solid elements. The integration point +data is written in the same order that it is stored in memory-each +material model has its own history variables that are stored. For +user defined materials it is important to store the history data that +is needed for plotting before the data which is not of interest. +Number of additional integration point history variables written +to the binary database for both shell and thick shell elements for +each integration point, see NEIPH above. +Number of shell integration points written to the binary database, +see also *INTEGRATION_SHELL. If the default value of 3 is used +then results are output for the outermost (top) and innermost +(bottom) integration points together with results for the neutral +axis. If MAXINT is set to 3 and the element has 1 integration +point then all three results will be the same. If a value other than +3 is used then results for the first MAXINT integration points in +the element will be output. Note: If the element has an even +number of integration points and MAXINT is not set to 3 then +you will not get mid-surface results. See Remarks below. If +MAXINT is set to a negative number, MAXINT integration points +are output for each in plane integration point location and no +averaging is used. This can greatly increase the size of the binary +d3part database. +Set to 1 to dump strain tensors for solid, shell and thick shell +elements for plotting by LS-PrePost and ASCII file elout. For +shell and thick shell elements two tensors are written, one at the +innermost and one at the outermost integration point. For solid +elements a single strain tensor is written. +SIGFLG +Flag for including the stress tensor for shells. +EQ.1: include (default), +EQ.2: exclude. +EPSFLG +Flag for including the effective plastic strains for shells. +EQ.1: include (default), +EQ.2: exclude. +VARIABLE +DESCRIPTION +RLTFLG +Flag for including stress resultants for shells. +EQ.1: include (default), +EQ.2: exclude. +ENGFLG +Flag for including shell internal energy density and shell +thickness. +EQ.1: include (default), +EQ.2: exclude. +IEVERP +Every plot state for d3part database is written to a separate file. +This option will limit the database to 1000 states: +EQ.0: more than one state can be on each plot file, +EQ.1: one state only on each plot file. +SHGE +Flag for including shell hourglass energy density. +EQ.1: off (default), no hourglass energy written, +EQ.2: on. +STSSZ +Flag for including shell element time step, mass, or added mass. +EQ.1: off (default), +EQ.2: output time step size, +EQ.3: output mass, added mass, or time step size. +See remark 3 below. +NINTSLD +Number of solid element integration points written. The default +value is 1. For solids with multiple integration points NINTSLD +may be set to 8. Currently, no other values for NINTSLD are +allowed. For solids with multiple integration points, an average +value is output if NINTSLD is set to 1. +*DATABASE_EXTENT_INTFOR +The following card controls to some extent the content of the optional intfor binary +database. See also *DATABASE_BINARY_INTFOR. The intfor database contains +geometry and time history data pertaining to those contact surfaces which are flagged +in *CONTACT with the variables SPR and/or MPR. The name of the intfor database +must be given on the execution line via “s=filename”. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NGLBV +NVELO +NPRESU NSHEAR +NFORC +NGAPC +NFAIL +IEVERF +Type +Default +I +1 +I +1 +I +1 +I +1 +I +1 +I +1 +I +0 +I +0 +Optional Card. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NWEAR +NWUSR +NHUF +Type +Default +I +0 +I +0 +I +0 + VARIABLE +DESCRIPTION +NGLBV +Output global variables: +EQ.-1: no, +EQ.1: yes (default). +NVELO +Output nodal velocity: +EQ.-1: no, +EQ.1: yes (default). +VARIABLE +DESCRIPTION +NPRESU +Output pressures: +EQ.-1: no, +EQ.1: normal interface pressure (default), +EQ.2: normal interface pressure and peak pressure, +EQ.3: normal interface pressure, peak pressure and time to +peak. +NSHEAR +Output shear stresses: +EQ.-1: no, +EQ.1: shear stress in r-direction and s-direction (default). +NFORC +Output forces: +EQ.-1: no, +EQ.1: 𝑥-, 𝑦-, 𝑧-force at all nodes (default). +NGAPC +Output contact gaps at all nodes and surface energy density +EQ.-1: no, +EQ.1: yes (default). +NFAIL +Flag for display of deleted contact segments +EQ.0: all segments are displayed, +EQ.1: remove deleted contact segments from display. +IEVERF +Every interface force state for the “intfor” database is written to a +separate file: +EQ.0: more than one interface force state can be on each intfor +file, +EQ.1: one interface force output state only on each intfor file. +NWEAR +Output contact wear data, see *CONTACT_ADD_WEAR +EQ.0: No output. +GE.1: Output wear depth. +GE.2: Output sliding distance. +NWUSR +Number of user wear history variables to output from user +defined wear routines, see *CONTACT_ADD_WEAR. +Number of user friction history variables to output from user +defined friction routines, see *USER_INTERFACE_FRICTION +(MPP only). +*DATABASE + VARIABLE +NHUF +Remarks: +For gaps in Mortar contact, see NGAPC, these are measured with respect to the nominal +contact surfaces of the two interacting segments. For instance, if IGNORE = 2 on +*CONTACT_...MORTAR then an initial penetration 𝑑 will dislocate the slave contact +surface in the negative direction of the slave surface normal 𝒏. The gap 𝑔 reported to +the intfor file is still measured between the master and slave surface neglecting this +dislocation, thus only physical gaps are reported. +Wear outputs are governed by NWEAR and NWUSR, and requires the usage of a wear + For NWEAR the “wear depth” +model associated with the contact interface. +(NWEAR.GE.1) and “sliding distance” (NWEAR.GE.2) are listed under the Nodal +fringe menu in LS-PrePost. Following this, NWUSR user defined history variables are +listed, corresponding to user wear history variables in a user wear routine. These are +listed in the order that they are stored in the wear routine, see WTYPE.LT.0 on *CON- +TACT_ADD_WEAR. +*DATABASE +This keyword controls the content written to the BYU MOVIE databases. See movie +option on *DATABASE manual entry. +Varriable Cards. Define as many cards as needed. Input ends at next keyword (“*”) +card. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +VTYPE +COMP +Type +I +I + VARIABLE +DESCRIPTION +VTYPE +Variable type: +EQ.0: node, +EQ.1: brick, +EQ.2: beam, +EQ.3: shell, +EQ.4: thick shell. +COMP +. +Component +components from the following tables can be chosen: +the corresponding VTYPE, + For +ID. +integer +VTYPE.EQ.0: Table 10.1 , +VTYPE.EQ.1: Table 10.2 , +VTYPE.EQ.2: not supported, +VTYPE.EQ.3: Table 10.3 , +VTYPE.EQ.4: not supported. +*DATABASE_EXTENT_MPGS +Define as many cards as necessary. The created MPGS databases consist of a geometry +file and one file for each output database. See MPGS option to *DATABASE keyword. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +VTYPE +COMP +Type +I +I + VARIABLE +DESCRIPTION +VTYPE +Variable type: +EQ.0: node, +EQ.1: brick, +EQ.2: beam, +EQ.3: shell, +EQ.4: thick shell. +COMP +Component +components from the following tables can be chosen: +the corresponding VTYPE, + For +ID. +integer +VTYPE.EQ.0: Table 14-2 , +VTYPE.EQ.1: Table 14-3 , +VTYPE.EQ.2: not supported, +VTYPE.EQ.3: Table 14-4 , +VTYPE.EQ.4: not supported. +*DATABASE_EXTENT_SSSTAT_OPTION +The only OPTION is: +ID +The ID option allows the definition of a heading which will be written at the beginning +of the ASCII file ssstat. +Purpose: This command defines one or more subsystems. A subsystem is simply a set +of parts, grouped for convenience. The ASCII output file ssstat provides histories of +energy (kinetic, internal, hourglass) and momentum (x, y, and z) for each subsystem. +The ssstat file is thus similar to glstat and matsum, but whereas glstat provides data for +the whole model and matsum provides data for each individual part, ssstat provides +data for each subsystem. The output interval for the ssstat file is given using *DATA- +BASE_SSSTAT. To also include histories of subsystem mass properties in the ssstat file, +use *DATABASE_SSSTAT_MASS_PROPERTIES. +For *DATABASE_EXTENT_BINARY without the ID option, the following card(s) +apply. Define as many cards as necessary. Define one part set ID per subsystem, up to +8 subsystems per card. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PSID1 +PSID2 +PSID3 +PSID4 +PSID5 +PSID6 +PSID7 +PSID8 +Type +I +I +I +I +I +I +I +I +For *DATABASE_EXTENT_BINARY_ID option, the following card(s) apply. Define as +many cards as necessary. Define one part set ID per subsystem, 1 subsystem per card. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PSID1 +Type +I +HEADING1 +A70 + VARIABLE +DESCRIPTION +PSIDn +Part set ID for subsystem n; see *SET_PART. +VARIABLE +DESCRIPTION +HEADINGn +Heading for subsystem n. +*DATABASE +Purpose: Process FATXML data. FATXML is an open, standardized data format based +on the Extensible Markup Language (XML) which is developed by the German +Research Association of Automotive Technology (Forschungsvereinigung Automobil- +technik - FAT). It is designed for consistent data management in the overall CAE +process chain. A comprehensive explanation of the FATXML data format specification +is given by Schulte-Frankenfeld and Deiters [2016]. +LS-DYNA reads all lines between this keyword and the next keyword recognized by the +star (*) sign, processes the data with respect to the include file structure and writes +everything together in one output file called ‘d3plot.xml’. +Remarks: +It is intended that a corresponding FE model consists of one master file with several +associated include files each containing a description by *DATABASE_FATXML data, +usually at the end of the file. The master file loads the include files via *INCLUDE_- +TRANSFORM with potential offset values for nodes, elements, parts, etc. (IDNOFF, +IDEOFF, IDPOFF, …). Finally, all data from different include files with different offsets +are collected and then summarized in ‘d3plot.xml’. Since the resulting data format is +public domain, Post-Processors are able to read that data and correlate it with the +associated CAE model. +Example: +... +*DATABASE_FATXML + + + < PART_ID NAME=”TestCase”> + + ... + + < THICKNESS ID=”123”>1.0 + < THICKNESS ID=”124”>1.1 + ... + + ... + + + +*END +Purpose: Define the output format for binary files. +*DATABASE_FORMAT + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IFORM +IBINARY +Type +Default +Remarks +I +0 +1 +I +0 +2 + VARIABLE +DESCRIPTION +IFORM +Output format for d3plot and d3thdt files +EQ.0: LS-DYNA database format (default), +EQ.1: ANSYS database format, +EQ.2: Both LS-DYNA and ANSYS database formats. +IBINARY +Word size of the binary output files (d3plot, d3thdt, d3drlf and +interface files for 64 bit computer such as CRAY and NEC. +EQ.0: default 64 bit format, +EQ.1: 32 bit IEEE format +Remarks: +1. The ANSYS output option is not available in MPP and is not universally +available in SMP. The LS-DYNA banner in d3hsp will include “ANSYS data- +base format” under the list of “Features enabled” if the option is available. +2. By using this option one can reduce the size of the binary output files which are +created by 64 bits computer such as CRAY and NEC. +*DATABASE_FREQUENCY_ASCII_OPTION +Options for frequency domain ASCII databases with the default names given include: +NODOUT_SSD ASCII database for nodal results for SSD (displacement, velocity and +acceleration). See also *FREQUENCY_DOMAIN_SSD. + ELOUT_SSD +ASCII database for element results for SSD (stress and strain +components). See also *FREQUENCY_DOMAIN_SSD. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FMIN +FMAX +NFREQ +FSPACE +LCFREQ +Type +F +F +Default +0.0 +0.0 +I +0 +I +0 +I +0 + VARIABLE +DESCRIPTION +FMIN +FMAX +Minimum frequency for output (cycles/time) +Maximum frequency for output (cycles/time). +NFREQ +Number of frequencies for output. +FSPACE +Frequency spacing option for output: +EQ.0: linear +EQ.1: logarithmic +EQ.2: biased +LCFREQ +Load Curve ID defining the frequencies for output. +Remarks: +1. The keyword defines output frequencies for NODOUT_SSD and ELOUT_SSD, +and they can be different from output frequencies for D3SSD (which is defined +by keyword *DATABASE_FREQUENCY_BINARY_D3SSD). +2. The ASCII databases NODOUT_SSD and ELOUT_SSD are saved in binout files. +LS-PREPOST is able to read the binout files directly. Users can also convert +these files to ASCII format simply feed them to the l2a program like this: +fmin +fmin +fmin +Linear Spacing +Logarithmic Spacing +fmax +fmax +mode n +mode n+1 +mode n+2 +Biased Spacing +fmax +Figure 14-6. Spacing options of the frequency points. +l2a binout* +3. The nodes +to be output +to NODOUT_SSD are specified by card +*DATABASE_HISTORY_NODE. +4. The solid, beam, shell and thick shell elements to be output to ELOUT_SSD are +specified by the following cards: +*DATABASE_HISTORY_SOLID_{OPTION} +*DATABASE_HISTORY_BEAM_{OPTION} +*DATABASE_HISTORY_SHELL_{OPTION} +*DATABASE_HISTORY_TSHELL_{OPTION} +5. There are two methods to define the output frequencies. +a) The first method is to define FMIN, FMAX, NFREQ and FSPACE. FMIN +and FMAX specify the frequency range of interest and NFREQ specifies +the number of frequencies at which results are required. FSPACE speci- +fies the type of frequency spacing (linear, logarithmic or biased) to be +used. These frequency points for which results are required can be spaced +equally along the frequency axis (on a linear or logarithmic scale). Or they +can be biased toward the eigenfrequencies (the frequency points are +placed closer together at eigenfrequencies in the frequency range) so that +the detailed definition of the response close to resonance frequencies can +be obtained. +b) The second method is to use a load curve (LCFREQ) to define the frequen- +cies of interest. +*DATABASE_FREQUENCY_BINARY_OPTION +Options for frequency domain binary output files with the default names given include: +D3ACC +D3ACS +D3ATV +D3FTG +D3PSD +Binary output file for BEM acoustics (element acoustic pressure +contribution and contribution percentage). See also *FREQUEN- +CY_DOMAIN_ACOUSTIC_BEM. +Binary output file for FEM acoustics (acoustic pressure and sound +pressure level). See also *FREQUENCY_DOMAIN_ACOUSTIC_- +FEM. +Binary output file for acoustic transfer vectors given by BEM +acoustic analysis. See also *FREQUENCY_DOMAIN_ACOUSTIC_- +BEM_ATV. +Binary output file for random vibration fatigue analysis. See also +*FREQUENCY_DOMAIN_RANDOM_VIBRATION_FATIGUE. +Binary Power Spectral Density output file for random vibration +analysis. See also *FREQUENCY_DOMAIN_RANDOM_VIBRA- +TION. +D3RMS +D3SPCM +D3SSD +Binary Root Mean Square output file for random vibration analysis. +See also *FREQUENCY_DOMAIN_RANDOM_VIBRATION. +Binary output file for response spectrum analysis. See also *FRE- +QUENCY_DOMAIN_RESPONSE_SPECTRUM. +Binary output file for steady state dynamics. See also *FREQUEN- +CY_DOMAIN_SSD. +The D3ACC, D3ACS, D3ATV, D3FTG, D3PSD, D3RMS, D3SPCM and D3SSD files +contain plotting information to plot data over the three dimensional geometry of the +model. These databases can be plotted with LS-PrePost. +• The D3PSD file contains PSD state data for a range of frequencies. The D3SSD +file contains state data for a range of frequencies. +• For D3SSD, the data can be real or complex, depending on the variable BINARY +defined below. +• The D3ACC file contains acoustic pressure contribution (and contribution +percentage) from each of the boundary elements for a range of frequencies, +which are defined in the keyword *FREQUENCY_DOMAIN_ACOUSTIC_BEM. +• The D3ACS file contains acoustic results including acoustic pressure and sound +pressure level for a range of frequencies, which are defined in the keyword *FRE- +QUENCY_DOMAIN_ACOUSTIC_FEM. +• The D3FTG, D3RMS and D3SPCM files contain only one state each as they are +the data for cumulative fatigue damage ratio, root mean square for random +vibration and peak response for response spectrum analysis separately. +• The D3ATV file contains NFIELD × NFREQ states, where NFIELD is the number +of acoustic field points and NFREQ is the number of output frequencies. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +BINARY +Type +Default +I +- +Remarks +1 +Additional cards for D3ACC keyword options. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NID1 +NID2 +NID3 +NID4 +NID5 +NID6 +NID7 +NID8 +Type +Default +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +I +0 +Additional card for D3PSD and D3SSD keyword options. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +FMIN +FMAX +NFREQ +FSPACE +LCFREQ +Type +F +F +Default +0.0 +0.0 +I +0 +I +0 +I +VARIABLE +DESCRIPTION +BINARY +Flag for writing the binary plot file. +EQ.0: Off +EQ.1: write the binary plot file +EQ.2: write the complex variable binary plot file (D3SSD +only) +EQ.90: write only real part of frequency response (D3SSD only) +EQ.91: write only imaginary part of frequency response +(D3SSD only) +Field point node ID for writing D3ACC file (up to 10 NID are +allowed) +Minimum frequency for output (cycles/time) +Maximum frequency for output (cycles/time). +NID1,… +FMIN +FMAX +NFREQ +Number of frequencies for output. +FSPACE +Frequency spacing option for output: +EQ.0: linear +EQ.1: logarithmic +EQ.2: biased +LCFREQ +Load Curve ID defining the frequencies for output. +Remarks: +fmin +fmin +fmin +Linear Spacing +Logarithmic Spacing +fmax +fmax +mode n +mode n+1 +mode n+2 +Biased Spacing +fmax +Figure 14-7. Spacing options of the frequency points. +1. For OPTION = D3SSD, If BINARY = 1, only the magnitude of the displacement, +velocity, acceleration and stress response is written into the binary database +“d3ssd” which can be accessed by LS-PrePost 3.0 or older versions. For cus- +tomers using LS-PrePost 3.0 or older versions, it is suggested to set BINARY = +1. If BINARY = 2, both the magnitude and the phase angle of the response are +written into “d3ssd” so that LS-PrePost (3.1 or higher versions) can run modal +expansion (to show the cyclic time history fringe plot) on each output frequen- +cy. If BINARY = 90 or 91, only real or imaginary part of the response is written +into “d3ssd”. +2. There are two methods to define the output frequencies. +a) The first method is to define FMIN, FMAX, NFREQ and FSPACE. FMIN +and FMAX specify the frequency range of interest and NFREQ specifies +the number of frequencies at which results are required. FSPACE speci- +fies the type of frequency spacing (linear, logarithmic or biased) to be +used. These frequency points for which results are required can be spaced +equally along the frequency axis (on a linear or logarithmic scale). Or they +can be biased toward the eigenfrequencies (the frequency points are +placed closer together at eigenfrequencies in the frequency range) so that +the detailed definition of the response close to resonance frequencies can +be obtained. +b) The second method is to use a load curve (LCFREQ) to define the frequen- +cies of interest. +*DATABASE +Purpose: When a Lagrangian mesh overlaps with an Eulerian or ALE mesh, the fluid- +structure (or ALE-Lagrangian) interaction is often modeled using the *CON- +STRAINED_LAGRANGE_IN_SOLID card. This keyword (*DATABASE_FSI) causes +certain coupling information related to the flux through and load on selected +Lagrangian surfaces defined in corresponding *CONSTRAINED_LAGRANGE_IN_- +SOLID card to be written to the ASCII-based dbfsi file or in the case of MPP-DYNA the +binout file. +NOTE: This card must be associated with a *CON- +STRAINED_LAGRANGE_IN_SOLID penalty meth- +od coupling. This card is not compatible with +constrained-based coupling. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DTOUT +Type +F +Surface Card. Add one card per surface. This input terminates at the next keyword +(“*”) card. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable DBFSI_ID +SID +SIDTYPE +SWID +CONVID NDSETID +CID +Type +I +I +I +I +I +I +I + VARIABLE +DESCRIPTION +DTOUT +Output interval time step +DBFSI_ID +Surface ID (for reference purposes only) or a DATABASE_FSI +entity ID. It consists of a geometric entity defined by the SID +below. +SID +*DATABASE_FSI +DESCRIPTION +Set ID defining the geometrical surface(s) through which or upon +which some data is to be tracked and output to a file called +“dbfsi”. This set ID can be a (1) PID or (2) PSID or (3) SGSID. +This Lagrangian SID must be contained in a Lagrangian slave SID +defined in a corresponding coupling card, *CONSTRAINED_LA- +GRANGE_IN_SOLID. +SIDTYPE +Set type: +EQ.0: Part set +EQ.1: Part +EQ.2: Segment set +SWID +CONVID +This is an ID from a corresponding *ALE_FSI_SWITCH_MMG_- +ID card. This card allows for the AMMG ID of an ALE material +to be switched as it passes across a monitoring surface. If +defined, the accumulative mass of the “switched” ALE multi- +material group (AMMG) is written out under the “mout” +parameter in the “dbfsi” file. +This is used mostly for airbag application only: CONVID is an ID +from a corresponding *LOAD_ALE_CONVECTION_ID card +which computes the heat transfer between inflator gas (ALE +material) and the inflator canister (Lagrangian part). If defined, +the temperature of the Lagrangian part having heat transfer with +the gas, and its change in temperature as function of time are +output in the “dbfsi” file. +NDSETID +Set ID consisting of the nodes on which the moments of the forces +applied on SID are computed. See Remark 3. +CID +Coordinate system ID, see *DEFINE_COORDINATE_SYSTEM. +Remarks: +1. Overview of dbfsi File. The dbfsi parameters output are enumerated below. +pres = Averaged estimated coupling pressure over each surface entity +being monitored. For example, if using SI base units for mass- +length-time-temperature, this pressure would then be in Pascal. +fx, fy, fz = Averaged total estimated coupling force components (N in met- +ric units) along the global coordinate directions, over each sur- +face entity defined, and acting at the centroid of each surface. +mout = Accumulated mass (Kg in metric units) passing through each +DBFS_ID surface entity. See Remark 2 below. (This parameter +used to be called “pleak”). +obsolete = (This parameter used to be called “mflux”). + gx, gy, gz = Average estimated leakage-control force component over the +surface entity. This data is useful for debugging. Leakage con- +trol forces are too large (relative to the main coupling forces, fx, +fy and fz) may indicate that alternate coupling approach should +be considered since the main coupling force is putting out too +little resistance to leakage. (These parameters used to be called +fx-lc, fy-lc and fz-lc). +Ptmp = Lagrangian part Temperature (Activated only when the +*LOAD_ALE_CONVECTION card is used). +PDt = Lagrangian part Temperature change (Activated only when the +*LOAD_ALE_CONVECTION card is used). +2. MOUT. “mout” parameter in the “dbfsi” output from this keyword contains +the accumulated mass passing through each DBFS_ID surface entity. For 4 +different cases: +a) When LCIDPOR is defined in the coupling card (CLIS), porous accumu- +lated mass transport across a Lagrangian shell surface may be monitored +and output in “mout”. +b) Porous flow across Lagrangian shell may also be defined via a load curve +in the *MAT_FABRIC card, and similar result will be tracked and output. +This is an alternate form of (a). +c) When NVENT in the CLIS card is defined (isentropic venting), the venting +mass transport across the isentropic vent hole surface may be output in +“mout”. +d) When an *ALE_FSI_SWITCH_MMG_ID card is defined, and the SWID +parameter specifies this ID to be tracked, then the amount of accumulated +mass that has been switched when passing across a monitoring surface is +output. +3. Calculation of Moments for NDSETID. A geometrical surface SID has a +centroid where the coupling forces are averaged. The distances between this +centroid and the nodes defined by the set NDSETID are the lever arms. The +moments are the cross-products of these distances with the averaged coupling +forces. For each node in the set NDSETID, a new line in the “dbfsi” file is in- +serted after each output for the corresponding coupling forces . +These additional lines have the format following the template established by +the example in Remark 1 where the forces are replaced by the moments and the +node ID replaces the DBFSI_ID values. +Example: +Consider a model with a Lagrangian mesh overlaps with an Eulerian or ALE mesh. On +the Lagrangian mesh, there are 3 Lagrangian surface sets over which some data is to be +written out. +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +$ INPUT: +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*DATABASE_FSI +$ dt + 2.97E-06 +$ DBFSI_ID SID STYPE swid convid [STYPE: 0=PSID;1=PID;2=SGSID] + 11 1 2 + 12 2 2 + 13 3 1 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +$ This reads: +$ DBFSI_ID 11 is defined by a SID=1: a SGSID = as specified by STYPE=2 +$ DBFSI_ID 12 is defined by a SID=2: a SGSID = as specified by STYPE=2 +$ DBFSI_ID 13 is defined by a SID=3: a PID = as specified by STYPE=1 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +$ An OUTPUT file called “dbfsi” looks like the following: +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 + Fluid-structure interaction output + Number of surfaces: 3 + id pres fx fy fz mout + obsolete gx gy gz Ptmp +PDt + time= 0.00000E+00 + 11 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 + 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 +0.0000E+00 + 12 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 + 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 +0.0000E+00 + 13 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 + 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 +0.0000E+00 + time= 0.29709E-05 + 11 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 + 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 +0.0000E+00 +12 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 + 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 +0.0000E+00 + 13 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 + 0.1832E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 +0.0000E+00 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*DATABASE_FSI_SENSOR +Purpose: This card activates the output of an ASCII file called “dbsensor”. Its input +defines the pressure sensors’ locations which follow the positions of some Lagrangian +segments during the simulation. Its ASCII output file, dbsensor, contains the spatial +position of the sensor and its recorded pressure from the ALE elements containing the +sensors. This card is activated when a *CONSTRAINED_LAGRANGE_IN_SOLID card +is used and the Lagrangian shell elements defining the locations of the sensors must be +included in the slave or structure coupling set. +2 +3 +4 +5 +6 +7 +8 + Card 1 +Variable +1 +DT +Type +F +Surface Card. Add one card per surface. This input terminates at the next keyword +(“*”) card. +Card +1 +2 +3 +4 +5 +6 +7 +8 +Variable DBFSI_ID +NID +SEGMID +OFFSET +ND1 +ND2 +ND3 +Type +I +I +I +F +I +I +I + VARIABLE +DESCRIPTION +DT +Output interval +DBFSI_ID +Pressure-Sensor ID. +NID +SEGMID +An optional Lagrangian node ID defining an approximate +pressure sensor location with respect to a Lagrangian shell +element. This is not a required input. +A required Lagrangian element ID for locating the pressure +sensor. If NID = 0 or blank, the sensor will be automatically +placed in the center of this SEGMID, accounting for the offset +distance. If the model is 3D, the Lagrangian element can be a +shell or solid (for this latter, ND1 and ND2 are required to define +the face). If the model is 2D, the Lagrangian element can be a +beam or shell (for this latter, ND1 and ND2 are required to define +the side). +DESCRIPTION +Offset distance between the pressure sensor and the Lagrangian +segment surface. If it is positive, it is on the side pointed to by the +segment normal vector and vice versa. +Nodes defining the solid face in 3D or shell side in 2D, from +which the sensor is located. In 3D, if the solid face has 4 nodes, +only the diagonal opposites ND1 and ND2 are required. If the +solid face is triangular, a third node ND3 should be provided. In +2D, only ND1 and ND2 are required to define the shell side. + VARIABLE +OFFSET +ND1, ND2, +ND3 +Remarks: +1. The output parameters in the “dbsensor” ASCII file are: +ID = Sensor ID. + x, y, z = Sensor spatial location. +P = Sensor recorded pressure (Pa) from the ALE fluid element con- +taining the sensor. +For example, to plot the sensor pressure in LS-Prepost, select: +ASCII → dbsensor → LOAD → (select sensor ID) → Pressure → PLOT +Example 1: +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +$ INPUT: +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +*DATABASE_FSI_SENSOR + 0.01 +$ DBFSI_ID NID SEGMENTID OFFSET + 10 360 355 -0.5 + 20 396 388 -0.5 + 30 324 332 -0.5 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +$ The 1st line reads: +$ SENSOR_ID 10 is located by segment-ID=355. Node-ID=360 precisely locate this +$ sensor (if NID=0, then the sensor is located at the segment center). This +$ sensor is located 0.5 length unit away from the segment surface. Negative +$ sign indicates a direction opposite to the segment normal vector. +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +$ An OUTPUT file called “dbsensor” looks like the following: +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 + ALE sensors output + Number of sensors: 3 + id x y z p + time= 0.17861E-02 + 10 0.0000E+00 0.0000E+00 -0.3900E+00 0.1085E-03 +20 -0.2250E+02 0.2250E+02 -0.3900E+00 0.1085E-03 + 30 0.2250E+02 -0.2250E+02 -0.3900E+00 0.1085E-03 + time= 0.20081E-02 + 10 0.0000E+00 0.0000E+00 -0.3900E+00 0.1066E-03 + 20 -0.2250E+02 0.2250E+02 -0.3900E+00 0.1066E-03 + 30 0.2250E+02 -0.2250E+02 -0.3900E+00 0.1066E-03 +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +$ ID = DBFSI_ID +$ x,y,z = Sensor location (defined based on a Lagrangian segment) +$ p = Sensor pressure as taken from the fluid element containing the sensor. +$...|....1....|....2....|....3....|....4....|....5....|....6....|....7....|....8 +Available options include: +*DATABASE +BEAM +BEAM_SET +BEAM_ID +DISCRETE +DISCRETE_ID +DISCRETE_SET +NODE +NODE_ID +NODE_LOCAL +NODE_LOCAL_ID +NODE_SET +NODE_SET_LOCAL +SEATBELT +SEATBELT_ID +SHELL +SHELL_ID +SHELL_SET +SOLID +SOLID_ID +SOLID_SET +SPH +SPH_SET +TSHELL +TSHELL_ID +*DATABASE_HISTORY +Purpose: Control which nodes or elements are output into the binary history file, +d3thdt, the ASCII file nodout, the ASCII file elout and the ASCII file sphout. Define as +many cards as necessary. The next “*” card terminates the input. See also *DATA- +BASE_BINARY_OPTION and *DATABASE_OPTION. +Node/Element Cards for Case I (no “ID”, and no “LOCAL”). Cards for keyword +options BEAM, BEAM_SET, DISCRETE, DISCRETE_SET, NODE, NODE_SET, SEAT- +BELT, SHELL, SHELL_SET, SOLID, SOLID_SET, SPH, SPH_SET, TSHELL, and +TSHELL_SET. Include as many as needed. Input terminates at the next keyword (“*”) +card. + Card 1 +1 +Variable +ID1 +2 +ID2 +3 +ID3 +4 +ID4 +5 +ID5 +6 +ID6 +7 +ID7 +8 +ID8 +Type +I +I +I +I +I +I +I +I + VARIABLE +IDn +DESCRIPTION +NODE/NODE_SET or element/element set ID n. Elements may +be BEAM/BEAM_SET, DISCRETE/DISCRETE_SET, SEATBELT, +TSHELL/ +SHELL/SHELL_SET, +TSHELL_SET. The contents of the files are given in Table 14-2 for +nodes, Table 14-3 for solid elements, Table 14-4 for shells and +thick shells, and Table 14-5 for beam elements. In the binary file, +D3THDT, the contents may be extended or reduced with the +*DATABASE_EXTENT_BINARY definition. +SOLID/SOLID_SET, +or +Node/Element Cards for Case II (“ID” option, but no “LOCAL”). Cards for keyword +options BEAM_ID, NODE_ID, SEATBELT_ID, SHELL_ID, SOLID_ID, and TSHELL_ID. +Include as many as needed. Input terminates at the next keyword (“*”) card. + Card 1 +Variable +1 +ID +Type +I +2 +3 +4 +5 +6 +7 +8 +HEADING +A70 + VARIABLE +DESCRIPTION +ID +Node or element ID +VARIABLE +HEADING +DESCRIPTION +A description of the node or element. It is suggested that unique +descriptions be used. This description is written into the D3HSP +file and into the ASCII databases nodout and elout. +Node Cards for Case III (“LOCAL” option). Card 1 for keyword options NODE_LO- +CAL, NODE_LOCAL_ID, and NODE_SET_LOCAL. Include as many cards as needed +to specify all the nodes. This input terminates at the next keyword (“*”) card. + Card 1 +Variable +1 +ID +2 +3 +4 +5 +6 +7 +8 +CID +REF +HFO +Type +I +I +I +I +ID Card for Case III. Additional card for ID option. This card is only used for the +NODE_LOCAL_ID keyword option. When activated, each node is specified by a pair +of cards consisting of “Card 1,” and, secondly, this card. Include as many pairs as +needed to specify all the nodes. This input terminates at the next keyword (“*”) card. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +HEADING +A70 + VARIABLE +DESCRIPTION +ID +CID +NODE/NODE_SET set ID. The contents of the files are given in +Table 14-2 for nodes. + See the remark below concerning +accelerometer nodes. +Coordinate system ID for nodal output. See DEFINE_COORDI- +NATE options. +REF +*DATABASE_HISTORY +DESCRIPTION +Output coordinate system for displacements, velocities, and +accelerations. (Nodal coordinates are always in the global +coordinate system.) +EQ.0: Output is in the local system fixed for all time from the +beginning of the calculation. If CID is nonzero, FLAG in +the corresponding *DEFINE_COORDINATE_NODES +command must be set to 0. FLAG has no bearing on +results when REF is set to 1 or 2. +EQ.1: Translational output is the projection of the node’s +absolute translational motion onto the local system. The +local system is defined by the *DEFINE_COORDI- +NATE_NODES command and can change orientation +according to the movement of the three defining nodes. +The defining nodes can belong to either deformable or +rigid parts. +EQ.2: Translational output is the projection of the node’s +relative translational motion onto the local system. Here, +“relative” means relative to node N1 of that local system. +In other words, the displacement of the origin (node N1) +of the local coordinate system is first subtracted from the +displacement of the node of interest before projecting it +onto the translating and rotating local coordinate system. +The local system is defined as described in REF = 1 +above. If dynamic relaxation is used, the reference loca- +tion is reset when convergence is achieved. Rotational +output is truly relative to the updated location coordi- +nate system only if REF = 2. +HFO +Flag for high frequency output into nodouthf +EQ.0: Nodal data written to nodout file only +EQ.1: Nodal data also written nodouthf at the higher frequency +HEADING +A description of the nodal point. It is suggested that unique +description be used. This description is written into the d3hsp +file and into the ASCII database nodout. +Remarks: +1. +If a node belongs to an accelerometer, see *ELEMENT_SEATBELT_AC- +CELEROMETER, and if it also appears as an active node in the NODE_LOCAL +or NODE_SET_LOCAL keyword, the coordinate system, CID, transformations +will be skipped and the LOCAL option will have no effect. +*DATABASE_MASSOUT +Purpose: Output nodal masses into ASCII file MASSOUT. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SETID +NDFLG +RBFLG +Type +Default +I +0 +I +1 +I +0 + VARIABLE +DESCRIPTION +SETID +Optional set ID. +EQ.0: mass output for all nodes, +LT.0: no output, +GT.0: set ID identifying nodes whose mass will be output. +NDFLG +Database extent: +EQ.1: output +translational mass +identified by SETID (default), +for deformable nodes +EQ.2: output translational mass and rotary inertias for the +deformable nodes identified by the SETID. +EQ.3: output translational mass for deformable and rigid +nodes identified by SETID (default), +EQ.4: output translational mass and rotary inertias for the +deformable and rigid nodes identified by the SETID. +RBFLG +Rigid body data: +EQ.0: no output for rigid bodies, +EQ.1: output rigid body mass and inertia. +Remarks: +1. Nodes and rigid bodies with no mass are not output. By inference, when the +set ID is zero and no output shows up for a node, then the mass of that node is +zero. +*DATABASE_NODAL_FORCE_GROUP +Purpose: Define a nodal force group for output into the ASCII file nodfor. The output +interval must be specified using *DATABASE_NODFOR . + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NSID +CID +Type +I +I +Default +none +none + VARIABLE +DESCRIPTION +Nodal set ID, see *SET_NODE_OPTION. +Coordinate system ID for output of data in local system, +NSID +CID +Remarks: +1. The reaction forces in the global 𝑥, 𝑦, and 𝑧 directions (and local 𝑥, 𝑦, and 𝑧 +directions if CID is defined above) for the nodal force group are written to the +nodfor file along with the external work done by +these reaction forces. The reaction forces in the global 𝑥, 𝑦, and 𝑧 directions for +each node in the nodal force group are also written to nodfor. These forces can +be a result of applied boundary forces such as nodal point forces and pressure +boundary conditions, body forces, and contact interface forces. In the absence +of body forces, interior nodes would always yield a null force resultant vector. +In general this option would be used for surface nodes. +*DATABASE_PAP_OUTPUT +Purpose: Set contents of output files for pore air pressure calculations. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IVEL +IACCX +IACCY +IACCZ +NCYOUT +Type +Default +I +0 +I +0 +I +0 +I +0 +I +100 + VARIABLE +DESCRIPTION +IVEL +Meaning of “Velocity” in d3plot and d3thdt output files +EQ.0: Nodal velocity vector +EQ.1: Seepage velocity vector +IACCX, Y, Z +Meaning of “X/Y/Z-Acceleration” in d3plot and d3thdt output +files +EQ.0: Not written +EQ.21: Nodal air density +EQ.22: Nodal pore air pressure +EQ.24: Nodal air mass +EQ.25: Nodal air mass flow rate +NCYOUT +Number of cycles between outputs of calculation status to d3hsp +and log files +*DATABASE +Purpose: Plot the distribution or profile of a data along x, y, or z-direction. + Card 1 +Variable +1 +DT +Type +I +2 +ID +I +3 +4 +5 +6 +7 +8 +TYPE +DATA +DIR +UPDLOC +MMG +I +I +I +I +0 +I +0 +Default +none +none +none +none +none + VARIABLE +DESCRIPTION +DT +ID +Interval time. +Set ID. +TYPE +Set type: +EQ.1: Node Set, +EQ.2: Solid Set, +EQ.3: Shell Set, +EQ.4: Segment Set, +EQ.5: Beam Set. +DATA +Data type: +EQ.1: 𝑥-velocity, +EQ.2: 𝑦-velocity, +EQ.3: 𝑧-velocity, +EQ.4: velocity magnitude, +EQ.5: 𝑥-acceleration, +EQ.6: 𝑦-acceleration, +EQ.7: 𝑧-acceleration, +EQ.8: acceleration magnitude, +EQ.9: pressure, +EQ.10: 𝑥𝑥-stress, +VARIABLE +DESCRIPTION +EQ.11: 𝑦𝑦-stress, +EQ.12: 𝑧𝑧-stress, +EQ.13: 𝑥𝑦-stress, +EQ.14: 𝑦𝑧-stress, +EQ.15: 𝑧𝑥-stress, +EQ.16: temperature, +EQ.17: volume fraction, +EQ.18: kinetic energy, +EQ.19: internal energy, +EQ.20: density. +DIR +Direction: +EQ.1: 𝑥-direction, +EQ.2: 𝑦-direction, +EQ.3: 𝑧-direction, +EQ.4: Curvilinear (relative distances between elements of set +ID are added up in the order defined by the set) +UPDLOC +Flag to update the set location: +EQ.0: Only the initial position of set ID is considered +EQ.1: The positions of the elements composing the set are +updated each DT +MMG +Multi-Material ALE group id. See Remark 2. +GT.0: Multi-Material ALE group id +LT.0: |MMG| is the id of a *SET_MULTI-MATERIAL_- +GROUP_LIST that can list several Multi-Material ALE +group ids. +Remarks: +1. At a given time 𝑇 the profile is written in a file named profile_DATA_- +DIR_timeT.xy (DATA and DIR are replaced by the data and direction names +respectively). The file has a xyplot format that LS-PrePost can read and plot. +For example, DATA = 9, DIR = 2 and DT = 0.1 sec will save a pressure profile at +𝑡 = 0.0 sec in profile_pressure_y_time0.0.xy, at 𝑡 = 0.1 sec in profile_pressure_y_ +time0.1.xy, at 𝑡 = 0.2 sec in profile_pressure_y_time0.2.xy. +2. +In the case of a multi-material ALE model (elform = 11 in *SECTION_SOLID or +*SECTION_ALE2D or *SECTION_ALE1D), an element can contain several +materials with each material being associated with its own pressures and +stresses. It is the default behavior for volume averaging to be applied to ele- +ment data before being written out; however, when the multi-material group +field, MMG, is set, then element data are output only for the specified materials. +*DATABASE_PWP_FLOW +Purpose: Request output containing net inflow of fluid at a set of nodes. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +NSET +Type +Default +I +0 + VARIABLE +DESCRIPTION +NSET +Node set ID +Remarks: +Any number of these cards can be used. Nett inflow or outflow arises when +maintaining an applied PWP boundary condition implies addition or removal of water. +Output is written to a file named database_pwp_flow.csv, a comma-separated ascii file. +Each line consists of (time, flow1, flow2, …) where flow1 is the total inflow at the node +set for the first DATABASE_PWP_FLOW request, flow2 is for the second, etc. +*DATABASE +Purpose: Set contents of output files for pore pressure calculations. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IVEL +IACCX +IACCY +IACCZ +NCYOUT +Type +Default +I +0 +I +0 +I +0 +I +0 +I +100 + VARIABLE +DESCRIPTION +IVEL +Meaning of “Velocity” in d3plot and d3thdt output files +EQ.0: Nodal velocity vector +EQ.1: Seepage velocity vector +IACCX, Y, Z +Meaning of “X/Y/Z-Acceleration” in d3plot and d3thdt output +files +EQ.0: Not written +EQ.1: Total pwp head +EQ.2: Excess pwp head (this is also written as temperature) +EQ.3: Target rate of volume change +EQ.4: Actual rate of volume change +EQ.7: Hydraulic pwp head +EQ.8: Error in rate of volume change (calculated from +seepage minus actual) +EQ.9: Volume at node +EQ.10: Rate of volume change calculated from seepage +EQ.14: Void volume (generated at suction limit) +EQ.17: NFIXCON (e.g: +4/-4 for nodes on suction limit) +NCYOUT +Number of cycles between outputs of calculation status to +d3hsp, log, and tdc_control_output.csv files (time-dependent +and steady-state analysis types). +*DATABASE_RCFORC_MOMENT +Purpose: Define contact ID and nodes for moment calculations. Moments are written +to rcforc according to output interval given in *DATABASE_RCFORC. If *DATA- +BASE_RCFORC_MOMENT is not used, the moments reported to rcforc are about the +origin (0, 0, 0). + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CID +NODES +NODEM +Type +I +I +I + VARIABLE +DESCRIPTION +CID +Contact ID +NODES +NODEM +Node about which moments are calculated due to contact forces +on slave surface. +Node about which moments are calculated due to contact forces +on master surface. +*DATABASE +Purpose: Recovers the stresses at nodal points of solid or thin shell elements by using +Zienkiewicz-Zhu’s Superconvergent Patch Recovery method. +5 +6 +7 +8 + Card 1 +1 +Variable +PSID +Type +Default +I +0 +2 +IAX +A +0 +3 +IAY +A +0 +4 +IAZ +A +0 + VARIABLE +PSID +DESCRIPTION +Part set ID of solid or thin shell elements whose nodal stress will +be recovered +IAX, IAY, IAZ +Meaning of “𝑥/𝑦/𝑧-Acceleration” in d3plot and d3thdt output +files +EQ.SMNPD: the minimum principal deviator stress +EQ.SMNPR: the minimum principal stress +EQ.SMXPD: the maximum principal deviator stress +EQ.SMXPR: the maximum principal stress +EQ.SMXSH: the maximum shear stress +EQ.SPR: +nodal pressure +EQ.SVM: +nodal von Mises stress +EQ.SXX: +EQ.SYY: +EQ.SZZ: +EQ.SXY: +EQ.SYZ: +EQ.SZX: +nodal normal stress along 𝑥 direction +nodal normal stress along 𝑦 direction +nodal normal stress along 𝑧 direction +nodal shear stress along 𝑥-𝑦 direction +nodal shear stress along 𝑦-𝑧 direction +nodal shear stress along 𝑧-𝑥 direction +For shell elements append either “B” or “T” to the input string to +recover nodal stresses at the bottom or top layer of shell +elements. For example, SPRT recovers the nodal pressure at the +top layer. +*DATABASE_RECOVER_NODE +1. Recovered stresses are in global coordinate system. +*DATABASE_SPRING_FORWARD +Purpose: Create spring forward nodal force file. This option is to output resultant +nodal force components of sheet metal at the end of the forming simulation into an +ASCII file, “SPRING-FORWARD”, for spring forward and die corrective simulations. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IFLAG +Type +I + VARIABLE +DESCRIPTION +IFLAG +Output type: +EQ.0: off, +EQ.1: output element nodal force vector for deformable nodes. +*DATABASE_SUPERPLASTIC_FORMING +Purpose: Specify the output intervals to the superplastic forming output files. The +option *LOAD_SUPERPLASTIC_FORMING must be active. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DTOUT +Type +F + VARIABLE +DTOUT +DESCRIPTION +Output time interval for output to “pressure”, “curve1” and +“curve2” files. The “pressure” file contains general information +from the analysis and the files “curve1” and “curve2” contain +pressure versus time from phases 1 and 2 of the analysis. The +data in the pressure and curve files may be plotted using ASCII → +superpl in LS-PrePost. +*DATABASE +Purpose: Tracer particles will save a history of either a material point or a spatial point +into an ASCII file: trhist. This history includes positions, velocities, and stress +components. The option *DATABASE_TRHIST must be active. This option applies to +ALE, SPH and DEM (Discrete Element Method) problems. +Available options are: + +DE +The DE option defines a tracer corresponding to discrete elements (*ELEMENT_DIS- +CRETE_SPHERE) . See Remarks 2 and 4. +Card +1 +2 +Variable +TIME +TRACK +Type +F +Default +0.0 +I +0 +3 +X +F +0 +4 +Y +F +0 +5 +Z +F +0 +6 +7 +8 +AMMGID +NID +RADIUS +I +0 +I +0 +F +0.0 + VARIABLE +DESCRIPTION +TIME +Start time for tracer particle +TRACK +Tracking option: +EQ.0: particle follows material, +EQ.1: particle is fixed in space. +X +Y +Z +Initial 𝑥-coordinate +Initial 𝑦-coordinate +Initial 𝑧-coordinate +AMMGID +The AMMG ID (ALE multi-material group) of the material being +tracked in a multi-material ALE element. See Remark 1. +NID +*DATABASE_TRACER +DESCRIPTION +An optional node ID defining the initial position of a tracer +particle. If defined, its coordinates will overwrite the 𝑥, 𝑦, 𝑧 +coordinates above. This feature is for TRACK = 0 only and can be +applied to ALE tracers and DE tracers. See Remark 2. +RADIUS +Radius is used only for the DE option to indicate whether the +tracer follows and monitors a single discrete element or multiple +discrete elements. +GT.0: The tracer takes the average results of all discrete +elements located inside a sphere with radius = RADIUS. +That sphere stays centered on the DE tracer. +LT.0: The discrete element closest to the tracer is used. The +magnitude of RADIUS in this case is unimportant. +Remarks: +1. Multi-Material Groups. ALE elements can contain multi-materials. Each +material is referred to as an ALE multi-material group or AMMG. Each AMMG +has its list of history variables that can be output. For example, if a tracer is in a +mixed element consisting of 2 AMMGs, and the history variables of AMMG 1 +are to be output or tracked, the AMMGID should be defined as AMMGID=1. If +AMMGID=0, a volume-fraction-weighted-averaged pressure will be reported +instead. +2. NID Description. For ALE, NID is a massless dummy node. Its location will +be updated according to the motion of the ALE material. +For the DE option, NID is a discrete element node that defines the initial loca- +tion of the tracer. The DE tracer continues to follow that node if RADIUS < 0. +On the other hand, the DE tracer’s location is updated according to the average +motion of the group of DE nodes inside the sphere defined by RADIUS when +RADIUS > 0. +3. Tracer particles in ambient ALE elements. Since the auxiliary variables (6 +stresses, plastic strain, internal energy, …) for ambient elements are reset to +their initial values before and after advection and tracer data are stored in trhist +during the advection cycle, tracers in ambient elements show the initial stresses, +not the current ones. +4. Discrete Elements. If _DE is used, tracer particles will save a history of either +a material point or a spatial point into an ASCII file: demtrh. This history in- +cludes positions, velocities components, stress components, porosity, void ratio, +and coordination number. The option *DATABASE_TRHIST must be active. +*DATABASE_TRACER_GENERATE +Purpose: Generate tracer particles along an isosurface for a variable defined in the +VALTYPE list. The tracer particles follow the motion of this surface and save data +histories into a binary file called trcrgen_binout . These histories +are identical to the ones output by *DATABASE_TRACER into the trhist file. They +include positions, velocities, and stress components. Except for the positions and +element id specifying where the tracer is, the output can be controlled with the +VARLOC and VALTYPE2 fields. This option applies to ALE problems. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DT +VALOW +VALUP +VALTYPE1 +SET +SETYPE MMGSET +UPDT +Type +F +F +F +I +Default +none +0.0 +0.0 +none +I +0 +I +0 +I +F +none +0.0 +Optional Variable Cards. Cards defining new variables to be output to t +trcrgen_binout instead of the default ones. Include as many cards as necessary. This +input ends at the next keyword (“*”) card. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +VARLOC VALTYPE2 MMGSET +Type +Default +I +0 +I +0 +I +0 + VARIABLE +DT +VALOW, +VALUP +DESCRIPTION +Interval time between each tracer generation and position +update . +Range of values between which the isosurface is defined. +VALOW is the lower bound while VALUP is the upper bound. +See Remark 2. The value at the isosurface is 0.5(VALOW + +VALUP). + The variable with this value is defined by +VALTYPE. +VARIABLE +VALTYPE1 +VALTYPE2 +DESCRIPTION +The variable that will be used to generate the isosurfaces. See +VALTYPE2 for enumeration of values. +Data to be output to the trcrgen_binout file. The interpretation +of VALTYPE1 and VALTYPE2 is enumerated in the following +list: +EQ.1: +EQ.2: +EQ.3: +EQ.4: +EQ.5: +EQ.6: +EQ.7: +EQ.8: +EQ.9: +EQ.10: +𝑥𝑥-stress +𝑦𝑦-stress +𝑧𝑧-stress +𝑥𝑦-stress +𝑦𝑧-stress +𝑧𝑥-stress +plastic strain +internal energy +bulk viscosity +relative volume +GE.11 and LE.19: +other auxiliary variables +EQ.20: +EQ.21: +EQ.22: +EQ.23: +EQ.24: +EQ.25: +EQ.26: +EQ.27: +EQ.28: +EQ.29: +EQ.30: +EQ.31: +EQ.31: +EQ.33: +EQ.34: +pressure +density +material volume +compression ratio +element volume fraction +nodal volume fraction +𝑥-position +𝑦-position +𝑧-position +𝑥-velocity +𝑦-velocity +𝑧-velocity +velocity +𝑥-acceleration +𝑦- acceleration +*DATABASE_TRACER_GENERATE +EQ.35: +EQ.36: +EQ.37: +EQ.38: +DESCRIPTION +𝑧- acceleration +acceleration +nodal mass +nodal temperature +SET +Set ID +SETYPE +Type of set : +EQ.0: +EQ.1: +EQ.2: +solid set +segment set +node set +MMGSET +Multi-material group set . +UPDT +Time interval between tracer position update . +VARLOC +Variable location in trcrgen_binout to be replaced with the +variable specified in the VALTYPE2 field: +EQ.4: +EQ.5: +EQ.6: +EQ.7: +EQ.8: +EQ.9: +EQ.10: +EQ.11: +EQ.12: +EQ.13: +EQ.14: +EQ.15: +𝑥-velocity +𝑦-velocity +𝑧-velocity +𝑥𝑥-stress +𝑦𝑦-stress +𝑧𝑧-stress +𝑥𝑦-stress +𝑦𝑧-stress +𝑧𝑥-stress +plastic strain +density +relative volume +Remarks: +1. DT. The frequency to create tracers is defined by DT. The default value of +UPDT, which is the time interval between updates to the tracer position, is also +set to DT. The default behavior, then, is to update tracer positions when a new +tracer is created, however, by setting UPDT to a value less than DT tracer posi- +tions can be updated more frequently without creating new tracers. +2. Tracing Algorithm. When LS-DYNA adds new tracer particles tracers +are created at element centers, segment centers, or nodes depending on the set +type (SETYPE). A new tracer particle is created when the value at the element +center, segment center, or node center is in the bounding interval [VALOW, +VALUP], provided that there is not already a nearby tracer particle. The tracer +particles follow the iso-surface defined by the midpoint of the bounding inter- +val (VALOW + VALUP)/2. +3. Multi-Material Groups. ALE elements can contain several materials. Each +material is referred to as an ALE multi-material group. The volume fractions +define how much of the element volume is occupied by the groups. Each group +has their own variables for 0 +ID +ID Card. Additional card for the ID keyword option. + Optional +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DID +Type +I +Default +none +HEADING +A70 +None + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IPID +ITYPE +NQ +IPDES +ISDES +RSF +OUTDES +Type +I +I +I +I +I +F +Default +none +none +None +none +None +1.0 +I +0 + VARIABLE +DESCRIPTION +DID +Definition ID. This must be a unique number. +HEADING +Definition descriptor. It is suggested that unique descriptions be +used. +IPID +ID of the solid part or part set to transform. +Figure 15-1. Left to right, illustration of conversion from solid to DES for +NQ = 2 of hexahedron, pentahedron, and tetrahedron elements. + VARIABLE +DESCRIPTION +ITYPE +IPID type: +EQ.0: Part ID, +NE.1: Part set ID. +NQ +Adaptive option for hexahedral elements. For tetrahedral and +pentahedral elements, see Remark 1: +EQ.1: Adapt one solid element to one discrete element, +EQ.2: Adapt one solid element to 8 discrete elements, +EQ.3: Adapt one solid element to 27 discrete elements. +IPDES +ISDES +Part ID for newly generated discrete elements, See Remark 2. +Section ID for discrete elements, See Remark 2. +RSF +DES radius scale down factor. +OUTDES +Allow user output generated discrete element nodes and DES +properties toa keyword file. +EQ.0: No output. (Default) +EQ.1: Write data under filename, desvfill.inc +Remarks: +1. DES Element to Sold Element Ratio. The DES particles are evenly distribut- +ed within the solid element. For hexahedral elements the number of the gener- +ated DES particles is NQ × NQ × NQ. For pentahedral elements, the number of +generated DES particles is 1, 6, and 18 for NQ = 1, 2, and 3 respectively. For +tetrahedral elements, the number generated DES particles is 1, 4, and 10 for +NQ = 1, 2, and 3 respectively. See Figure 15-1. +2. Part ID. The Part ID for newly generated DES particles can be either a new Part +ID or the ID of an existing DES Part. +*DEFINE_ADAPTIVE_SOLID_TO_SPH_{OPTION} +Purpose: Adaptively transform a Lagrangian solid Part or Part Set to SPH particles, +when the Lagrangian solid elements comprising those parts fail. One or more SPH +particles (elements) will be generated for each failed element. The SPH particles +replacing the failed solid Lagrangian elements inherit all the Lagrange nodal quantities +and all the Lagrange integration point quantities of these failed solid elements. Those +properties are assigned to the newly activated SPH particles. The constitutive +properties assigned to the new SPH part will correspond to the MID and EOSID +referenced by the SPH *PART definition. +The available options include: + +ID +ID Card. Additional card for the ID keyword option. + Optional +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DID +Type +I +Default +none +HEADING +A70 +none + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +IPID +ITYPE +NQ +IPSPH +ISSPH +ICPL +IOPT +CPCD +Type +I +I +I +I +I +I +I +F +Default +none +none +none +none +none +none +none +average + VARIABLE +DESCRIPTION +DID +Definition ID. This must be a unique number. +HEADING +Definition descriptor. It is suggested that unique descriptions be +used. +VARIABLE +DESCRIPTION +IPID +ID of the solid part or part set to transform. +ITYPE +IPID type: +EQ.0: Part ID, +NE.0: Part set ID. +NQ +Adaptive option for hexahedral elements. For tetrahedral and +pentahedral elements, see remark 1: +EQ.n: Adapt one 8-node solid element to (𝑛 × 𝑛 × 𝑛) SPH +elements. The range of n is from 1 to 8. +IPSPH +Part ID for newly generated SPH elements, See Remark 2. +ISSPH +Section ID for SPH elements, See Remark 2. +ICPL +Coupling of newly generated SPH elements to the adjacent solid +elements: +EQ.0: Failure without coupling (debris simulation), +EQ.1: Coupled to Solid element. +EQ.3: Pure thermal coupling between SPH part and Solid part +(combined with IOPT = 0 option, See Remark 4). +IOPT +Coupling method (for ICPL = 1 only See Remark 3): +EQ.0: Coupling from beginning (used as constraint between +SPH elements and Solid elements), +EQ.1: Coupling begins when Lagrange element fails. +CPCD +Thermal coupling conductivity between SPH part and Solid part +for ICPL = 3 option. The default value is set as the average value +of the conductivity from SPH part and the conductivity from Solid +part. +Remarks: +1. The SPH particles are evenly distributed within the solid element. For +hexahedral elements the number of the generated SPH particles is NQ*NQ*NQ. +For pentahedral elements, the number of generated SPH particles is 1, 6, and 18 +for NQ = 1, 2, and 3 respectively. For tetrahedral elements, the number gener- +ated SPH particles is 1, 4, and 10 for NQ = 1, 2, and 3 respectively. +2. The Part ID for newly generated SPH particles can be either a new Part ID or +the ID of an existing SPH Part. For constraint coupling (i.e. ICPL = 1 and +IOPT = 0), the newly generated SPH part ID should be different from the exist- +ing one. +3. +4. +ICPL = 0 is used for debris simulation, no coupling happens between newly +generated SPH particles and solid elements, the user needs to define node to +surface contact for the interaction between those two parts. When ICPL = 1 and +IOPT = 1, the newly generated SPH particles are bonded with solid elements as +one part through the coupling, and the new material ID with different failure +criteria can be applied to the newly generated SPH particles. +ICPL = 3 (combined with IOPT = 0) is used for pure thermal coupling between +SPH part and Solid part only. User can define the coupling thermal conductivi- +ty value between SPH part and Solid part through CPCD parameter for more +realistic thermal coupling between SPH part and Solid part. +SPH node +Example of SPH nodes for +hexahedron +element with +NQ = 2 +Example of SPH nodes for +pentahedron element with +NQ = 2 +Example of SPH nodes +tetrahedron element with NQ = 2 +for a +Available options include: + +LOCAL +*DEFINE_BOX +Purpose: Define a box-shaped volume. Two diagonally opposite corner points of a box +are specified in global or local coordinates if the LOCAL option is active. The box +volume is then used for various specifications for a variety of input options, e.g., +velocities, contact, etc. +If the option, LOCAL, is active, a local coordinate system with two vectors, see Figure +15-7, is defined. The vector cross product, 𝑧 = 𝑥 × 𝑦, determines the local z-axis. The +local y-axis is then given by 𝑦 = 𝑧 × 𝑥. A point, X in the global coordinate system is +considered to lie with the volume of the box if the coordinate X - C, where C is the +global coordinate offset vector defined on Card 3, lies within the box after transfor- +mation into the local system, XC_local = T × ( X – C ). The local coordinate, XC_local, is +checked against the minimum and maximum coordinates defined on Card 1 in the local +system. For the *INCLUDE_TRANSFORM options that include translations and +rotations, all box options are automatically converted from *DEFINE_BOX_xxxx to *DE- +FINE_BOX_xxxx_LOCAL in the DYNA.INC file. Here, xxxx represents the box options: +ADAPTIVE, COARSEN, and SPH, which are defined below. +Card +1 +2 +3 +4 +5 +6 +7 +8 +Variable +BOXID +XMN +XMX +YMN +YMX +ZMN +ZMX +Type +Default +I +0 +F +F +F +F +F +F +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +8 +*DEFINE_BOX +Local Card 1. First additional card for LOCAL keyword option. + Card 2 +Variable +1 +XX +Type +F +2 +YX +F +3 +ZX +F +4 +XV +F +5 +YV +F +6 +ZV +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Local Card 2. Second additional card for LOCAL keyword option. +4 +5 +6 +7 +8 + Card 3 +Variable +1 +CX +Type +F +2 +CY +F +3 +CZ +F +Default +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +BOXID +Box ID. Define unique numbers. +XMN +XMX +YMN +YMX +ZMN +ZMX +Minimum x-coordinate. Define in the local coordinate system if +the option LOCAL is active. +Maximum x-coordinate. . Define in the local coordinate system if +the option LOCAL is active. +Minimum y-coordinate. . Define in the local coordinate system if +the option LOCAL is active. +Maximum y-coordinate. . Define in the local coordinate system if +the option LOCAL is active. +Minimum z-coordinate. . Define in the local coordinate system if +the option LOCAL is active. +Maximum z-coordinate. . Define in the local coordinate system if +the option LOCAL is active. +XX +YX +ZX +XV +YV +ZV +CX +CY +CZ +*DEFINE_BOX +DESCRIPTION +X-coordinate on local x-axis. Origin lies at (0,0,0). Define if the +LOCAL option is active. +Y-coordinate on local x-axis. Define if the LOCAL option is +active. +Z-coordinate on local x-axis. Define if the LOCAL option is +active. +X-coordinate of local x-y vector. Define if the LOCAL option is +active. +Y-coordinate of local x-y vector. Define if the LOCAL option is +active. +Z-coordinate of local x-y vector. Define if the LOCAL option is +active. +X-global coordinate of offset vector to origin of local system. +Define if the LOCAL option is active. +Y-global coordinate of offset vector to origin of local system. +Define if the LOCAL option is active. +Z-global coordinate of offset vector to origin of local system. +Define if the LOCAL option is active. +Available options include: + +LOCAL +*DEFINE +Purpose: Define a box-shaped volume enclosing (1) the shells where the h-adaptive +level (2) the solids where the tetrahedron r-adaptive mesh size is to be specified. If the +midpoint of the element falls within the box, the h-adaptive level is reset. With the +additions of LIDX/NDID, LIDY and LIDZ, the box can be made movable; it is also +possible to define a fission box followed by a fusion box and the mesh could refine +when deformed and coarsen when flattened. Shells falling outside of this volume use +the value, MAXLVL, on the *CONTROL_ADAPTIVE control cards. Another related +keyword includes: *DEFINE_CURVE_BOX_ADAPTIVITY. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +BOXID +XMN +XMX +YMN +YMX +ZMN +ZMX +Type +I +F +F +F +F +F +F +Default +none +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +PID +LEVEL +LIDX/NDID +LIDY +LIDZ +BRMIN +BRMAX +Type +Default +I +0 +I +1 +I +0 +I +0 +I +0 +F +F +0.0 +0.0 +Local Card 1. First additional card for LOCAL keyword option. See *DEFINE_BOX +for a description of the LOCAL option. + Card 3 +Variable +1 +XX +Type +F +2 +YX +F +3 +ZX +F +4 +XV +F +5 +YV +F +6 +ZV +F +7 +8 +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Local Card 2. Second additional card for LOCAL keyword option. +4 +5 +6 +7 +8 + Card 4 +Variable +1 +CX +Type +F +2 +CY +F +3 +CZ +F +Default +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +BOXID +Box ID. Define unique numbers. +XMN +XMX +YMN +YMX +ZMN +ZMX +Minimum x-coordinate. Define in the local coordinate system if +the option LOCAL is active. +Maximum x-coordinate. Define in the local coordinate system if +the option LOCAL is active. +Minimum y-coordinate. Define in the local coordinate system if +the option LOCAL is active. +Maximum y-coordinate. Define in the local coordinate system if +the option LOCAL is active. +Minimum z-coordinate. Define in the local coordinate system if +the option LOCAL is active. +Maximum z-coordinate. Define in the local coordinate system if +the option LOCAL is active. +VARIABLE +DESCRIPTION +PID +LEVEL +Deformable part ID. If zero, all active elements within box are +considered. +Maximum number of refinement levels for elements that are +contained in the box. Values of 1, 2, 3, 4,... allow a maximum of +1, 4, 16, 64, ... elements, respectively, to be created for each +original element. +LIDX/NDID +Load curve ID/Node ID. +GT.0: load curve ID. + Define adaptive box movement +(displacement vs. time) in global X axis. +LT.0: absolute value is a node ID, whose movement will be +followed by the moving adaptive box. The node ID can +be on a moving rigid body. +EQ.0: no movement. +LIDY +Load curve ID. +GT.0: load curve ID. + Define adaptive box movement +(displacement vs. time) in global Y axis. +EQ.0: no movement. +LIDZ +Load curve ID. +GT.0: load curve ID. + Define adaptive box movement +(displacement vs. time) in global Z axis. +EQ.0: no movement. +BRMIN +Minimum mesh size in 3D tetrahedron adaptivity +BRMAX +Maximum mesh size in 3D tetrahedron adaptivity +XX +YX +ZX +XV +X-coordinate on local x-axis. Origin lies at (0,0,0). Define if the +LOCAL option is active. +Y-coordinate on local x-axis. Define if the LOCAL option is +active. +Z-coordinate on local x-axis. Define if the LOCAL option is +active. +X-coordinate of local x-y vector. Define if the LOCAL option is +active. +*DEFINE_BOX_ADAPTIVE +DESCRIPTION +Y-coordinate of local x-y vector. Define if the LOCAL option is +active. +Z-coordinate of local x-y vector. Define if the LOCAL option is +active. +X-global coordinate of offset vector to origin of local system. +Define if the LOCAL option is active. +Y-global coordinate of offset vector to origin of local system. +Define if the LOCAL option is active. +Z-global coordinate of offset vector to origin of local system. +Define if the LOCAL option is active. +YV +ZV +CX +CY +CZ +Remarks: +The moving adaptive box is very useful and efficient in situation where deformation +progresses while happening only locally, such as roller hemming and incremental +forming simulation. With the moving box feature, elements entering one box can be +refined and fused together when they enter another box. Mesh fission outside of the +moving box envelope is controlled by MAXLVL and other parameters under +*CONTROL_ADAPTIVE. The fusion controls (NCFREQ, IADPCL) can be defined +using *CONTROL_ADAPTIVE. Currently, only IADPCL = 1 is supported. +Only when one of the LCIDX/NDID, LICDY, or LCIDZ is defined, the adaptive box +will be moving; otherwise it will be stationary. +For 3D tetrahedron r-adaptivity, the current implementation does not support LOCAL +option. In card 2, PID, BRMIN and BRMAX are the only parameters currently +supported in 3D r-adaptivity. +Example: +Referring to a partial input deck below, and Figure 15-2, a strip of sheet metal is being +roller hemmed. The process consists of pre- and final hemming. Each pre- and final +roller is defined with a moving adaptive box ID 2 and 3, respectively, with the box +shapes shown in Figure 15-2. The first box, a fission box, was set at LEVEL = 3, while +the second box, a fusion box, was set at LEVEL = 1. Elements outside of the volume +envelope made by the moving boxes undergo no fission and fusion (MAXLVL = 1). +This settings allows mesh fission when entering the moving box 2 (LEVEL = 3), fusion +only when elements entering the moving box 3 (LEVEL = 1), no fusion/fusion +(MAXLVL = 1) at all outside of the volume envelope created by the moving boxes. In +the example, the boxes 2 and 3 are to be moved in global X direction for a distance of +398mm defined by load curve 11, and 450mm defined by load curve 12, respectively. +*CONTROL_TERMINATION +0.252 +*CONTROL_ADAPTIVE +$ ADPFREQ ADPTOL ADPOPT MAXLVL TBIRTH TDEATH LCADP IOFLAG + 8.05E-4 0.200000 2 1 0.0001.0000E+20 0 1 +$ ADPSIZE ADPASS IREFLG ADPENE ADPTH MEMORY ORIENT MAXEL + 0.300000 1 0 5.0 +$ IADPN90 NCFREQ IADPCL ADPCTL CBIRTH CDEATH + -1 0 1 1 10.0 0.000 10.30 +*DEFINE_BOX_ADAPTIVE +$# BOXID XMN XMX YMN YMX ZMN ZMX + 2 -10.00000 36.000000 -15.03000 3.991000 1.00E+00 48.758000 +$# PID LEVEL LIDX/NDID LIDY LIDZ + 6 3 11 +*DEFINE_BOX_ADAPTIVE +$# BOXID XMN XMX YMN YMX ZMN ZMX + 3 -100.0000 -60.0000 -15.03000 3.991000 1.00E+00 48.758000 +$# PID LEVEL LIDX/NDID LIDY LIDZ + 6 1 12 +*DEFINE_CURVE +11 + 0.000 0.0 + 0.00100000 1.0 + 0.19900000 397.0 + 0.20000000 398.0 + 1.000 398.0 + ⋮ + ⋮ +*DEFINE_CURVE +12 + 0.0 0.0 + 0.05 0.0 + 0.051 1.0 + 0.251 401.0 + 0.252 450.0 + ⋮ + ⋮ +A moving box can also follow the movement of a node, which can be on a moving rigid +body. In this case, load curves defining the boxes’ movement can be skipped, instead, +NDIDs for the boxes should be defined. For example, in Figure 15-2 and a partial +keyword example below, box 2 is to follow a node (ID: 33865) on the pre-roller, and box +3 to follow another node (ID: 38265) on the final roller. +*DEFINE_BOX_ADAPTIVE +$# BOXID XMN XMX YMN YMX ZMN ZMX + 2 -10.00000 36.000000 -15.03000 3.991000 1.00E+00 48.758000 +$# PID LEVEL LIDX/NDID LIDY LID + 6 3 -33865 +*DEFINE_BOX_ADAPTIVE +$# BOXID XMN XMX YMN YMX ZMN ZMX + 3 -100.0000 -60.0000 -15.03000 3.991000 1.00E+00 48.758000 +$# PID LEVEL LIDX/NDID LIDY LID + 6 3 -38265 +*DEFINE_BOX_ADAPTIVE +The variables LIDX/NDID, LIDY, LIDZ are available in both SMP and MPP starting in +Revision 98718. +Fission box: LEVEL=3, +follows Node 38265 +Node 33865 +Inner part +Outer flange +Hem bed +Roller path +Pre-roller +Node 38265 +Final roller +Fusion box 3: LEVEL=1, +follows Node 33865 +Hem bed +Mesh fissioned after +pre-rollers' passing +Mesh fuzed after all +rollers' passing +Inner part +Original mesh +Roller path +Outer flange +Figure 15-2. Defining mesh fission and fusion. +*DEFINE_BOX_COARSEN_{OPTION} +Available options include: + +LOCAL +Purpose: Define a specific box-shaped volume indicating elements which are protected +from mesh coarsening. See also *CONTROL_COARSEN. +Card +1 +2 +3 +4 +5 +6 +7 +8 +Variable +BOXID +XMN +XMX +YMN +YMX +ZMN +ZMX +IFLAG +Type +I +F +F +F +F +F +F +Default +none +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +I +0 +Local Card 1. First additional card for LOCAL keyword option. See *DEFINE_BOX +for a description of the LOCAL option. + Card 2 +Variable +1 +XX +Type +F +2 +YX +F +3 +ZX +F +4 +XV +F +5 +YV +F +6 +ZV +F +7 +8 +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Local Card 2. Second additional card for LOCAL keyword option. +4 +5 +6 +7 +8 + Card 3 +Variable +1 +CX +Type +F +2 +CY +F +3 +CZ +F +Default +0.0 +0.0 +0.0 +VARIABLE +DESCRIPTION +BOXID +Box ID. Define unique numbers. +XMN +XMX +YMN +YMX +ZMN +ZMX +Minimum x-coordinate. Define in the local coordinate system if +the option LOCAL is active. +Maximum x-coordinate. . Define in the local coordinate system if +the option LOCAL is active. +Minimum y-coordinate. . Define in the local coordinate system if +the option LOCAL is active. +Maximum y-coordinate. . Define in the local coordinate system if +the option LOCAL is active. +Minimum z-coordinate. . Define in the local coordinate system if +the option LOCAL is active. +Maximum z-coordinate. . Define in the local coordinate system if +the option LOCAL is active. +IFLAG +Flag for protecting elements inside or outside of box. +EQ.0: elements inside the box cannot be coarsened +EQ.1: elements outside the box cannot be coarsened +XX +YX +ZX +XV +YV +ZV +CX +X-coordinate on local x-axis. Origin lies at (0,0,0). Define if the +LOCAL option is active. +Y-coordinate on local x-axis. Define if the LOCAL option is +active. +Z-coordinate on local x-axis. Define if the LOCAL option is +active. +X-coordinate of local x-y vector. Define if the LOCAL option is +active. +Y-coordinate of local x-y vector. Define if the LOCAL option is +active. +Z-coordinate of local x-y vector. Define if the LOCAL option is +active. +X-global coordinate of offset vector to origin of local system. +Define if the LOCAL option is active. +Y-global coordinate of offset vector to origin of local system. +Define if the LOCAL option is active. +Z-global coordinate of offset vector to origin of local system. +Define if the LOCAL option is active. +*DEFINE + VARIABLE +CY +CZ +Remarks: +1. Many boxes may be defined. If an element is protected by any box then it may +not be coarsened. +*DEFINE +Purpose: Define a specific box or tube shaped volume around a draw bead. This option +is useful for the draw bead contact. If box shaped, the volume will contain the draw +bead nodes and elements between the bead and the outer edge of the blank. If tubular, +the tube is centered around the draw bead. All elements within the tubular volume are +included in the contact definition. +Card +1 +2 +3 +4 +5 +6 +7 +8 +Variable +BOXID +PID +SID +IDIR +STYPE +RADIUS +CID +Type +Default +I +0 +F +F +F +0.0 +0.0 +0.0 +I +4 +F +0.0 +I +0 +Remarks +optional optional + VARIABLE +DESCRIPTION +BOXID +Box ID. Define unique numbers. +PID +SID +IDIR +Part ID of blank. +Set ID that defines the nodal points that lie along the draw bead. +If a node set is defined, the nodes in the set must be consecutive +along the draw bead. If a part or part set is defined, the set must +consist of beam or truss elements. Within the part set, no +ordering of the elements is assumed, but the number of nodes +must equal the number of beam elements plus 1. +Direction of tooling movement. The movement is in the global +coordinate direction unless the tubular box option is active and +CID is nonzero. In this latter case, the movement is in the local +coordinate direction. +EQ.1: tooling moves in x-direction, +EQ.2: tooling moves in y-direction, +EQ.3: tooling moves in z-direction. +STYPE +Set type: +*DEFINE_BOX_DRAWBEAD +DESCRIPTION +EQ.2: part set ID, +EQ.3: part ID, +EQ.4: node set ID. +RADIUS +The radius of the tube, which is centered around the draw bead. +Elements of part ID, PID, that lie within the tube will be included +in the contact. If the radius is not defined, a rectangular box is +used instead. This option is recommended for curved draw +beads and for draw beads that are not aligned with the global +axes. +CID +Optional coordinate system ID. This option is only available for +the tubular drawbead. +Available options include: + +LOCAL +*DEFINE +Purpose: Define a box-shaped volume. Two diagonally opposite corner points of a box +are specified in global coordinates. Particle approximations of SPH elements are +computed when particles are located inside the box. The load curve describes the +motion of the maximum and minimum coordinates of the box. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +BOXID +XMN +XMX +YMN +YMX +ZMN +ZMX +VID +Type +I +F +F +F +F +F +F +Default +none +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +4 +5 +6 +7 + Card 2 +1 +Variable +LCID +Type +Default +I +0 +2 +VD +I +0 +3 +NID +I +0 +I +0 +Local Card 1. First additional card for LOCAL keyword option. See *DEFINE_BOX +for a description of the LOCAL option + Card 3 +Variable +1 +XX +Type +F +2 +YX +F +3 +ZX +F +4 +XV +F +5 +YV +F +6 +ZV +F +7 +8 +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Local Card 2. Second additional card for LOCAL keyword option. +4 +5 +6 +7 +8 + Card 4 +Variable +1 +CX +Type +F +2 +CY +F +3 +CZ +F +Default +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +BOXID +Box ID. Define unique numbers. +XMN +XMX +YMN +YMX +ZMN +ZMX +Minimum x-coordinate. Define in the local coordinate system if +the option LOCAL is active. +Maximum x-coordinate. Define in the local coordinate system if +the option LOCAL is active. +Minimum y-coordinate. Define in the local coordinate system if +the option LOCAL is active. +Maximum y-coordinate. Define in the local coordinate system if +the option LOCAL is active. +Minimum z-coordinate. Define in the local coordinate system if +the option LOCAL is active. +Maximum z-coordinate. Define in the local coordinate system if +the option LOCAL is active. +VARIABLE +DESCRIPTION +VID +LCID +Vector ID for DOF, see *DEFINE_VECTOR. +Load curve ID to describe motion value versus time, see *DE- +FINE_CURVE +VD +Velocity/Displacement flag: +EQ.0: velocity, +EQ.1: displacement, +EQ.2: referential node +NID +Referential nodal ID for VD = 2 (SPH box will move with this +node). +XX +YX +ZX +XV +YV +ZV +CX +CY +CZ +X-coordinate on local x-axis. Origin lies at (0,0,0). Define if the +LOCAL option is active. +Y-coordinate on local x-axis. Define if the LOCAL option is +active. +Z-coordinate on local x-axis. Define if the LOCAL option is +active. +X-coordinate of local x-y vector. Define if the LOCAL option is +active. +Y-coordinate of local x-y vector. Define if the LOCAL option is +active. +Z-coordinate of local x-y vector. Define if the LOCAL option is +active. +X-global coordinate of offset vector to origin of local system. +Define if the LOCAL option is active. +Y-global coordinate of offset vector to origin of local system. +Define if the LOCAL option is active. +Z-global coordinate of offset vector to origin of local system. +Define if the LOCAL option is active. +*DEFINE_CONNECTION_PROPERTIES_{OPTION} +Available options include: + +ADD +Purpose: Define failure related parameters for solid element spot weld failure by +*MAT_SPOTWELD_DAIMLERCHRYSLER. For each connection identifier, CON_ID, a +separate *DEFINE_CONNECTION_PROPERTIES section must be included. The ADD +option allows material specific properties to be added to an existing connection ID. See +Remark 2. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +CON_ID +PRUL +AREAEQ +DGTYP MOARFL +Type +Default +F +0 + Card 2 +1 +I +0 +2 +I +0 +3 +4 +I +0 +5 +I +0 +6 +7 +8 +Variable +DSIGY +DETAN +DDGPR +DRANK +DSN +DSB +DSS +Type +F +F +F +F +F +F +F +Default +none +none +1010 +none +none +none +none +Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +DEXSN +DEXSB +DEXSS +DLCSN +DLCSB +DLCSS +DGFAD DSCLMRR +Type +F +F +F +Default +1.0 +1.0 +1.0 +I +0 +I +0 +I +0 +F +F +none +1.0 +Material Specific Data: +For each shell material with material specific data, define for this CON_ID the following +two cards. Add as many pairs of cards as necessary. This input is terminated by the +next keyword (“*”) card. +Material Data Card 1. + Card 4 +1 +2 +3 +4 +5 +Variable +MID +SGIY +ETAN +DGPR +RANK +Type +F +F +F +F +F +Default +1010 +6 +SN +F +7 +SB +F +8 +SS +F +Material Data Card 2. + Card 5 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EXSN +EXSB +EXSS +LCSN +LCSB +LCSS +GFAD +SCLMRR +Type +F +F +F +I +I +I +F +F +Default + VARIABLE +CON_ID +1.0 +DESCRIPTION +Connection ID, referenced on *MAT_SPOTWELD_DAIMLER- +CHRYSLER. Multiple sets of connection data may be used by +assigning different connection IDs. +*DEFINE_CONNECTION_PROPERTIES +DESCRIPTION +PRUL +The failure rule number for this connection. +EQ.1: Use data of weld partner with lower RANK (default). +GE.2: Use DEFINE_FUNCTION expressions to determine +weld data depending on several values of both weld +partners. Variables DSIGY, DETAN, DDGPR, DSN, +DSB, DSS, DEXSN, DEXSB, DEXSS, and DGFAD must be +defined as function IDs, see Remark 5. +AREAEQ +Area equation number for the connection area calculation. +EQ.0: (default) Areatrue = Areamodelled +EQ.1: millimeter form; see Remark 4 +EQ.-1: meter form; see Remark 4 +DGTYP +Damage type +EQ.0: +EQ.1: +EQ.2: +no damage function is used +strain based damage +failure function based damage +EQ.3 or 4: fading energy based damage; see Remark 4 +MOARFL +Modeled area flag +EQ.0: Areamodelled goes down with shear (default) +EQ.1: Areamodelled stays constant +DSIGY +Default yield stress for the spot weld element. +DETAN +Default tangent modulus for the spot weld element. +DDGPR +Default damage parameter for hyperbolic based damage function. +DRANK +Default rank value. +DSN +DSB +DSS +Default normal strength. +Default bending strength. +Default shear strength. +DEXSN +Default exponent on normal stress term. +DEXSB +Default exponent on bending stress term. +VARIABLE +DESCRIPTION +DEXSS +Default exponent on shear stress term. +DLCSN +DLCSB +DLCSS +Default curve ID for normal strength scale factor as a function of +strain rate. +Default curve ID for bending strength scale factor as a function of +strain rate. +Default curve ID for shear strength scale factor as a function of +strain rate. +DGFAD +Default fading energy for damage type 3 and type 4. +DSCLMRR +Default scaling factor for torsional moment in failure function. +MID +SIGY +ETAN +DGPR +Material ID of the shell material for which properties are defined. +Yield stress to be used in the spot weld element calculation. +Tangent modulus to be used in the spot weld element calculation. +Damage parameter for hyperbolic based damage function. +RANK +Rank value. See Remark 4. +SN +SB +SS +EXSN +EXSB +EXSS +LCSN +LCSB +LCSS +Normal strength. +Bending strength. +Shear strength. +Exponent on normal stress term. +Exponent on bending stress term. +Exponent on shear stress term. +Curve ID for normal strength scale factor as a function of strain +rate. +Curve ID for bending strength scale factor as a function of strain +rate. +Curve ID for shear strength scale factor as a function of strain +rate. +*DEFINE_CONNECTION_PROPERTIES +DESCRIPTION +GFAD +Fading energy for damage type 3 and 4. +SCLMRR +Scaling factor for torsional moment in failure function. +Remarks: +1. Restriction to *MAT_SPOTWELD_DAIMLERCHHRYSLER. This keyword is +used only with *MAT_SPOTWELD_DAIMLERCHRYSLER. The data input is +used in a 3 parameter failure model. Each solid spot weld element connects +shell elements that may have the same or different materials. The failure model +assumes that failure of the spot weld depends on the properties of the welded +materials, so this keyword allows shell material specific data to be input for the +connection. The default data will be used for any spot weld connected to a shell +material that does not have material specific data defined, so it is not necessary +to define material specific data for all welded shell materials. +2. ADD Option. To simplify data input, the ADD keyword option allows material +specific data to be added to an existing *DEFINE_CONNECTION_PROPER- +TIES table. To use the ADD option, omit cards 2 and 3, and input only CON_- +ID on card 1. Then use cards 4 and 5 to input material specific data. For each +unique CON_ID, control parameters and default values must be input in one +set of *DEFINE_CONNECTION_PROPERTIES data. The same CON_ID may +be used for any number of sets of material specific data input with the ADD +option. +3. The Three Parameter Failure Function. The three parameter failure function +is +𝐹) +𝑓 = ( +𝜎𝑛 +𝜎𝑛 +𝑚𝑏 + + ( +𝑚𝑛 + + ( +𝜎𝑏 +𝜎𝑏 +where the three strength terms are SN, SB, and SS, and the three exponents are +EXSN, EXSB, and EXSS. The strengths may be a function of strain rate by using +the load curves, LCSN, LCSB, and LCSS. The peak stresses in the numerators +are calculated from force resultants and simple beam theory. +𝜏𝐹) +𝑚𝜏 + − 1 , +𝐹) +𝜎𝑛 = +𝑁𝑟𝑟 +, +𝜎𝑏 = +2 + 𝑀𝑟𝑡 +√𝑀𝑟𝑠 +, +𝜏 = SCLMRR × +𝑀𝑟𝑟 +2𝑍 ++ +2 + 𝑁𝑟𝑡 +√𝑁𝑟𝑠 +where the area is the cross section area of the weld element and Z is given by: +𝑍 = 𝜋 +𝑑3 +32 +where d is the equivalent diameter of the solid spot weld element assuming a +circular cross section. +4. Control Parameters PRUL, AREAQ. And DGTYP. There are three control +parameters that define how the table data will be used for the connection, +PRUL, AREAEQ, and DGTYP. PRUL determines how the parameters will be +used. Because each weld connects two shell surfaces, one weld can have two +sets of failure data as well as two values for ETAN and SIGY. For PRUL=1 +(default), a simple rule is implemented and the data with the lower RANK will +be used. For PRUL=2 or 3, function expressions can be used to determine the +data based on several input values from both weld partners . +The second control parameter is AREAEQ which specifies a rule for calculating +a true weld cross section area, 𝐴true to be used in the failure function in place of +the modeled solid element area, 𝐴. For AREAEQ = 1, 𝐴true is calculated by +(5√𝑡min shell) +𝐴true = +where 𝑡min shell is the thickness of the welded shell surface that has the smaller +thickness. For AREAEQ = −1, 𝐴true is calculated by +𝐴true = +( +1000 +√1000 × 𝑡min shell) +The equation for AREAEQ = 1 is valid only for a length unit of millimeters, and +AREAEQ = −1 is valid only for a length unit of meters. +The third control parameter, DGTYP, chooses from two available damage +types. For DGTYP = 0, damage is turned off and the weld fails immediately +when 𝑓 ≥ 0. For DGTYP > 0, damage is initiated when 𝑓 ≥ 0 and complete fail- +ure occurs when 𝜔 ≥ 1. For DGTYP = 1, damage growth is a function of plastic +strain: +𝜔 = +𝑝 − 𝜀failure +𝜀eff +− 𝜀failure +𝜀rupture +, +𝜀failure +≤ 𝜀eff +𝑝 ≤ 𝜀rupture +𝑝 is the effective plastic strain in the weld material. When the value of +where 𝜀eff +the failure function first exceeds zero, the plastic strain at failure𝜀failure + is set to +the current plastic strain, and the rupture strain is offset from the plastic strain +at failure by +𝜀rupture += 𝜀failure ++ RS − EFAIL +where RS and EFAIL are the rupture strain and plastic strain at failure which +are input on the *MAT_SPOTWELD_DAIMLERCHRYSLER card. If failure +occurs when the plastic strain is zero, the weld material yield stress is reduced +to the current effective stress such that damage can progress. +For DGTYP = 2, damage is a function of the failure function, f: +𝑓 ≥ 0 ⇒ 𝜔 = +𝑓rupture +where 𝑓rupture is the value of the failure function at rupture which is defined by +𝑓rupture = RS − EFAIL +and RS and EFAIL are input on the *MAT_SPOTWELD_DAIMLERCHRYSLER +card. +Because the DGTYP = 1 damage function is scaled by plastic strain, it will mon- +otonically increase in time. The DGTYP = 2 damage function is forced to be a +monotonically increasing function in time by using the maximum of the current +value and the maximum previous value. For both DGTYP = 1 and DGTYP = 2, +the stress scale factor is then calculated by +𝜎̂ = +DGPR × (1 − 𝜔) +𝜎 +𝜔 (1 ++ √1 ++ DGPR) + DGPR +This equation becomes nearly linear at the default value of DGPR which is 1010. +For DGTYP = 3, damage is a function of total strain: +𝜔 = +∆𝜀𝑛 +∆𝜀fading +where Δ𝜀𝑛 is the accumulated total strain increment between moment of dam- +age initiation (failure) and current time step 𝑡𝑛 +∆𝜀𝑛 = ∆𝜀𝑛−1 + ∆𝑡𝑛√ + tr(𝛆̇𝑛𝜺̇𝑛 +T) , +∆𝜀|𝑡failure = 0 +and 𝛥𝜀𝑓𝑎𝑑𝑖𝑛𝑔 is the total strain increment for fading (reduction of stresses to zero) +∆𝜀fading = +2 × GFAD +𝜎failure +where GFAD is the fading energy from input and 𝜎failure is the effective stress at +failure. The stress scale factor is then calculated by a linear equation +𝜎̂ = (1 − 𝜔)𝜎 +where 𝜎 is the Cauchy stress tensor at failure and 𝜔 is the actual damage value. +Problems can occur, if the loading direction changes after the onset of failure, +since during the damage process, the components of the stress tensor are kept +constant and hence represent the stress state at failure. +Therefore DGTYP = 4 should be used describing the damage behavior of the +spotweld in a more realistic way. For DGTYP = 4, damage is a function of the +internal work done by the spotweld after failure, +𝜎̂ = (1 − 𝜔)𝜎 ep, 𝜔 = +𝐺used +2 × GFAD +, 𝐺used = 𝐺used +𝑛−1 + det (𝐹𝑖𝑗𝜎𝑖𝑗 +epΔ𝜀𝑖𝑗) +Therein, 𝐹𝑖𝑗 is the deformation gradient. 𝜎 ep is a scaled Cauchy stress tensor +based on the undamaged Cauchy stress tensor 𝜎 wd and scaled in such a way +that the same internal work is done in the current time step as in the time step +before (equipotential): +𝜎 ep = 𝛼𝜎 wd, 𝛼 = +𝑛−1,epΔ𝜀𝑖𝑗 +𝜎𝑖𝑗 +wdΔ𝜀𝑖𝑗 +𝜎𝑖𝑗 +5. Failure Rule from *DEFINE_FUNCTION. The failure rule number PRUL = 2 or +3, is available starting with Release R7. To use this new option, 11 variables +have to be defined as function IDs: DSIGY, DETAN, DDGPR, DSN, DSB, DSS, +DEXSN, DEXSB, DEXSS, DGFAD, and DSCLMRR. +These functions depend on: +(t1, t2) = thicknesses of both weld partners +(sy1, sy2) = initial yield stresses at plastic strain +(sm1, sm2) = maximum engineering yield stresses +𝑟 = strain rate +𝑎 = spot weld area +For DSIGY = 100 Such a function could look like: +*DEFINE_FUNCTION + 100 + func(t1,t2,sy1,sy2,sm1,sm2,r,a)=0.5*(sy1+sy2) +All the listed arguments in their correct order must be included in the argument +list. For PRUL = 2, the thinner part is the first weld partner. For PRUL = 3, the +bottom part (nodes 1-2-3-4) is the first weld partner. Since material parameters +have to be identified from both weld partners during initialization, this feature +is only available for a subset of material models at the moment, namely material +types 24, 120, 123, and 124. This new option eliminates the need for the ADD +option. +*DEFINE_CONSTRUCTION_STAGES +Purpose: Define times and durations of construction stages. +Card +1 +2 +3 +4 +5 +6 +7 +8 +Variable +ISTAGE +ATS +ATE +ATR +RTS +RTE +Type +I +F +F +F +F +F +Default +none +0.0 +0.0 +none +ATS +ATE + VARIABLE +DESCRIPTION +ISTAGE +Stage ID +Analysis time at start of stage +Analysis time at end of stage +Analysis time duration of ramp +Real time at start of stage +Real time at end of stage +ATS +ATE +ATR +RTS +RTE +Remarks: +See also *CONTROL_CONSTRUCTION_STAGES and *DEFINE_STAGED_CON- +STRUCTION_PART. +The first stage should start at time zero. There must be no gaps between stages, i.e. +ATS for each stage must be the same as ATE for the previous stage. +The ramp time allows gravity loading and part stiffening/removal to be applied +gradually during the first time period ATR of the construction stage. +The analysis always runs in “analysis time” – typically measured in seconds. The “real +time” is used only as a number to appear on output plots and graphs, and is completely +arbitrary. A dynain file is written at the end of each stage. +*DEFINE +Purpose: Exclude tied nodes from being treated in specific contact interfaces. This +keyword is currently only available in the MPP version. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +EID +Type +I +Title +A70 +ID Card 1. This card sets the contact interface the ids of up to 7 tied interfaces. + Card 2 +1 +Variable +Target +Type +I +2 +C1 +I +3 +C2 +I +4 +C3 +I +5 +C4 +I +6 +C5 +I +7 +C6 +I +8 +C7 +I +Optional ID Cards. More tied interfaces. Include as many cards as necessary. + Card 2 +Variable +1 +C8 +Type +I +2 +C9 +I +3 +4 +5 +6 +7 +8 +C10 +C11 +C12 +C13 +C14 +C15 +I +I +I +I +I +I + VARIABLE +DESCRIPTION +EID +Title +Target +Exclusion ID +Exclusion Title +Contact interface from which tied nodes are to be excluded. This +must be the ID of a SINGLE_SURFACE, NODE_TO_SURFACE, +or SURFACE_TO_SURFACE contact with SOFT ≠ 2. +Ci +*DEFINE_CONTACT_EXCLUSION +DESCRIPTION +The IDs of TIED contacts: 7 on the first card and 8 per additional +card for as many cards as necessary. +Any node which is a slave node in one of these interfaces, and is +in fact tied, will not be processed (as a slave node) in the Target +interface. +Note that if a node is excluded from the Target by this +mechanism, contact forces may still be applied to the node due to +any slave or master nodes impacting the contact segments of +which it is a part (no contact SEGMENTS are deleted, only contact +NODES). +If the Target contact is of type SURFACE_TO_SURFACE, any tied +slave nodes are deleted from both the slave side (for the normal +treatment) and the master side (for the symmetric treatment). +*DEFINE +Purpose: Define a rectangular, a cylindrical, or a spherical volume in a local coordinate +system. The volume can be referenced by *SET_NODE_GENERAL for the purpose of +defining a node set consisting of nodes inside the volume, or by *CONTACT_... for the +purpose of defining nodes or segments on the slave side or the master side of the +contact . + Card 1 +1 +2 +3 +Variable +CVID +CID +TYPE +Type +Default +I +0 +I +0 +I +0 +4 +XC +F +0. +5 +YC +F +0. +6 +ZC +F +0. +7 +8 +Card 2 for Rectangular Prism. Use when type = 0. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +XMN +XMX +YMN +YMX +ZMN +ZMX +Type +F +F +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +Card 2 for Cylinder. Use when type = 1. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +LENGTH +RINNER +ROUTER D_ANGC +Type +F +F +F +F +Default +0.0 +0.0 +0.0 +0.0 +Card 2 for Sphere Use when type = 3. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +RINNER +ROUTER D_ANGS +Type +F +F +F +Default +0.0 +0.0 +0.0 + VARIABLE +DESCRIPTION +CVID +CID +TYPE +XC +YC +ZC +XMN +XMX +YMN +YMX +ZMN +ZMX +Contact volume ID +Coordinate system ID. Required for rectangular and cylindrical +volumes +Volume type. Set to 0 for rectangular, 1 for cylindrical, and 2 for +spherical. +x-coordinate which defines the origin of coordinate system or the +center of the sphere for type = 3 referenced to the global +coordinate system. +y-coordinate which defines the origin of coordinate system or the +center of the sphere for type = 3 referenced to the global +coordinate system. +z-coordinate which defines the origin of coordinate system or the +center of the sphere for type = 3 referenced to the global +coordinate system. +Minimum x-coordinate in local coordinate system. +Maximum x-coordinate in local coordinate system. +Minimum y-coordinate in local coordinate system. +Maximum y-coordinate in local coordinate system. +Minimum z-coordinate in local coordinate system. +Maximum z-coordinate in local coordinate system. +VARIABLE +LENGTH +DESCRIPTION +Length of cylinder originating at (XC,YC,ZC) and revolving +around the local x-axis. +RINNER +Inner radius of cylinder or sphere. +ROUTER +Outer radius of cylinder or sphere. +D_ANGC +D_ANGS +If the included angle between the axis of the cylinder and the +normal vector to the contact segment is less than this angle, the +segment is deleted. +If the included angle between a line draw from the center of the +sphere to the centroid of the segment, and the normal vector to +the contact segment is greater than this angle, the segment is +deleted. +*DEFINE_COORDINATE_NODES +Purpose: Define a local coordinate system with three node numbers. The local +cartesian coordinate system is defined in the following steps. If the primary direction is +along the x-axis, then the 𝑧-axis is computed from the cross product of 𝑥 and 𝑦̅, , 𝑧 = 𝑥 × 𝑦̅, then the 𝑦-axis is computed via 𝑦 = 𝑧 × 𝑥. A similar procedure +applies if the local axis is along the y or z axes. +Card +1 +Variable +CID +Type +Default +I +0 +2 +N1 +I +0 +3 +N2 +I +0 +4 +N3 +I +0 +5 +6 +7 +8 +FLAG +DIR +I +0 +A +X + VARIABLE +DESCRIPTION +CID +Coordinate system ID. A unique number has to be defined. +N1 +N2 +N3 +FLAG +ID of node located at local origin. +ID of node located along local x-axis if DIR = X, the y-axis if +DIR = Y, and along the z axis if DIR = Z. +ID of node located in local x-y plane if DIR = X, the local y-z plane +if DIR = Y, and the local z-x plane if DIR = Z. +Set to unity, 1, if the local system is to be updated each time step. +Generally, this option when used with nodal SPC's is not +recommended since it can cause excursions in the energy balance +because the constraint forces at the node may go through a +displacement if the node is partially constrained. +DIR +Axis defined by node N2 moving from the origin node N1. The +default direction is the x-axis. +Remarks: +1. The nodes N1, N2, and N3 must be separated by a reasonable distance and not +colinear to avoid numerical inaccuracies. +Figure 15-3. Definition of local coordinate system using three nodes when the +node N2 lies along the x-axis. +*DEFINE_COORDINATE_SYSTEM_{OPTION} +Available options include: + +IGES +Purpose: Define a local coordinate system. +This card implements the same method as *DEFINE_COORDINATE_NODES; but, +instead of reading coordinate positions from nodal IDs, it directly reads the three +coordinates from its data cards as Cartesian triples. +When the IGES option is active, LS-DYNA will generate the coordinate system from an +IGES file containing three straight curves representing the x, y, and z axes. See remark +4. +Card 1 for Keyword Option. + Card 1 +1 +Variable +CID +Type +Default +I +0 +2 +XO +F +3 +YO +F +4 +ZO +F +5 +XL +F +6 +YL +F +7 +ZL +F +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +8 +CIDL +I +0 +4 +5 +6 +7 +8 +Card 2 for Keyword Option. + Card 2 +Variable +1 +XP +Type +F +2 +YP +F +3 +ZP +F +Default +0.0 +0.0 +0.0 +*DEFINE + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Type +Default +FILENAME +C +none + VARIABLE +DESCRIPTION +CID +Coordinate system ID. A unique number has to be defined. +XO +YO +ZO +XL +YL +ZL +CIDL +XP +YP +ZP +X-coordinate of origin. +Y-coordinate of origin. +Z-coordinate of origin. +X-coordinate of point on local x-axis. +Y-coordinate of point on local x-axis. +Z-coordinate of point on local x-axis. +Coordinate system ID applied to the coordinates used to define +the current system. The coordinates X0, Y0, Z0, XL, YL, ZL, XP, +YP, and ZP are defined with respect to the coordinate system +CIDL. +X-coordinate of point in local x-y plane. +Y-coordinate of point in local x-y plane. +Z-coordinate of point in local x-y plane. +FILENAME +Name of the IGES file containing three curves . +Remarks: +1. The coordinates of the points must be separated by a reasonable distance and +not co-linear to avoid numerical inaccuracies. +Airbag +Application +Boundary +Constrained +Contact +Damping +Database +Define +Box +Coordinate +Vector +Elements +Initial +Load +Rigidwall +Set Data +Show +Cre +Mod +Del +Global +Local +Label: None +Coord +Type +*SYSTEM +Position +Node +New ID +C_Element +C_Edge +CID +Title +N+Xaxis +Nodes +TRAN +ROTA +Geopts +Refl +Origin +X-Axis +XYP +Avg_Cen +3PtCircle +C_Cur/Surf +Geometry +Compute +X: +Y: +Z: +Origin +XYPlane +Clear +AlongX +AlongY +AlongZ +Apply +Done +Cancel +NID +Create +Create Position +All +None +Rev +AList +Apply +Cancel +Write +Done +Create Entity +Figure 15-4. LS-PrePost4.0 Dialog for defining a coordinate system. +2. Care must be taken to avoid chains of coordinate transformations because there +is no guarantee that they will be executed in the correct order. +3. LS-PrePost. A coordinate system can be created using the dialog box located +at Model (main window) → CreEnt → Define → Coordinate. +This will activate a Define Coordinate dialog in the right pane. Select the Cre +radio button at the top of the right pane, and set the type dropdown to +*SYSTEM. The next set of radio buttons (below the title input box) sets the +method used to define the coordinate system. See Figure 15-4. +a) The N+Xaxis method generates a coordinate system from based on: +i) +ii) +a user specified origin, +one of the three global axes (this is a severe restriction), and +iii) a 3rd point. +N+Xaxis +Nodes +TRAN +ROTA +Geopts +Refl +Origin +X-Axis +XYP +Origin +X-Axis +XYPlane +Direction X +Clear + Figure 15-5. Subset of Create Entity dialog for both Nodes and Geopts methods. +The 3rd point, together with the specified global axis defines the new sys- +tem’s x-y plane. The remaining axes are derived using orthogonality and +right-handedness. This method requires the user to pick two points +which involves the Create Position dialog box, as shown in the left frame +of Figure 15-4. +NOTE: After defining each point in the Create Position dialog, it is very +important to use the done button. The Create Entity dialog stays +up and remains interactive while the Create Position dialog is also +up and interactive. This can be confusing. Returning to the Cre- +ate Entity dialog without choosing done is a common mistake. +b) The node method generates a coordinate system from three points: +i) +The first point specifies the origin. +ii) The first and second points together specify the x-axis. +iii) The three points together specify the x-y plane of the new coordi- +nate system. The y and z axis are derived from orthogonality and +right-handedness. +c) The Geopts option generates the new coordinate system from a global axis +and two points. With this method the new system’s z-axis is set from the +Direction drop-down. This new system’s x-y plane is, then, orthogonal to +the chosen direction. The remaining two points serve to define the origin +and the x-axis (by projecting the second point). This option is useful for +metal forming application, since, often times, only the z-axis is important +while the while the x and y axes are not. +Longest length curve +Local Z-axis +Mid-length curve +Local Y-axis +B3 +B2 +B1 +Shortest length curve +Local X-axis +Figure 15-6. Input curves (left). The generated local coordinate system is +written to the d3plot file as a part consisting of three beams (right). +4. +IGES. When option, IGES, is used, three curves in the IGES format will be used +to define a local coordinate system. IGES curve entity types 126, 110 and 106 +are currently supported. Among the three curves, the longest length will be +made as local Z-axis, the mid-length will be Y-axis and the shortest length X- +axis. Suggested X, Y and Z-axis length is 100mm, 200mm and 300mm, respec- +tively. +All the three curves must have one identical point, and will be used for the +origin of the new local coordinate system. The coordinate system ID for the +local system will be based on the IGES file name. The IGES file name must start +with a number, followed by an underscore “_”, or by a dot. The number pre- +ceding the file name will be used as the new local coordinate system ID, which +can then be referenced in *MAT_20 cards, for example. +After the LS-DYNA run, three beam elements of a new PID will be created in +place of the three curves representing the local X, Y, and Z-axis in the d3plot file +for viewing in LS-PrePost. See Figure 15-6. +The following partial input contains an example in which the keyword is used +to create a local coordinate system (CID = 25) from IGES input. The IGES file +named, 25_iges, contains three intersecting curves in one of the three supported +IGES entity types. The example demonstrates using the IGES coordinate sys- +tem (ID = 25) to specify the local coordinate system for a rigid body (PID = 2, +MID = 2). The keyword, *BOUNDARY_PRESCRIBED_MOTION_RIGID_ LO- +CAL, then uses this local coordinate system to assign velocities from load +curves 3 and 5 for the rigid body motion in the local x-direction. +*KEYWORD +*DEFINE_COORDINATE_SYSTEM_IGES_TITLE +Flanging OP25 +25_iges +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+--- +-8 +*PART +punch + 2 2 2 +*MAT_RIGID +$ MID RO E PR N COUPLE M +ALIAS + 2 7.830E-09 2.070E+05 0.28 +$ CMO CON1 CON2 + -1 25 011111 +$LCO or A1 A2 A3 V1 V2 V3 +25 +$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+--- +-8 +*BOUNDARY_PRESCRIBED_MOTION_RIGID_LOCAL +$ typeID DOF VAD LCID SF VID DEATH +BIRTH + 2 1 0 3 -1.0 0 0.00241 +0.0 + 2 1 0 5 -1.0 0 0.0115243 +0.00241 +The keyword can be repeated for each new coordinate system if multiple coor- +dinate systems are needed. +Revision information: +This option is available starting in LS-DYNA Revision 62798. +*DEFINE_COORDINATE_VECTOR +Purpose: Define a local coordinate system with two vectors, see Figure 15-7. The vector +cross product, 𝑧 = 𝑥 × 𝑥𝑦, determines the z-axis. The y-axis is then given by 𝑦 = 𝑧 × 𝑥. If +this coordinate system is assigned to a nodal point, then at each time step during the +calculation, the coordinate system is incrementally rotated using the angular velocity of +the nodal point to which it is assigned. +Card +1 +Variable +CID +Type +Default +I +0 +2 +XX +F +3 +YX +F +4 +ZX +F +5 +XV +F +6 +YV +F +7 +ZV +F +8 +NID +I +0.0 +0.0 +0.0 +0.0 +0.0 +0.0 +0. + VARIABLE +DESCRIPTION +CID +Coordinate system ID. A unique number has to be defined. +X-coordinate on local x-axis. Origin lies at (0,0,0). +Y-coordinate on local x-axis +Z-coordinate on local x-axis +X-coordinate of local x-y vector +Y-coordinate of local x-y vector +Z-coordinate of local x-y vector +Optional nodal point ID. The coordinate system rotates with the +rotation of this node. If the node is not defined, the coordinate +system is stationary. +XX +YX +ZX +XV +YV +ZV +NID +Remarks: +1. These vectors should be separated by a reasonable included angle to avoid +numerical inaccuracies. +2. +Ideally, this nodal point should be attached to a rigid body or a structural part +where the nodal point angular velocities are meaningful. It should be noted +that angular velocities of nodes may not be meaningful if the nodal point is +attached only to solid elements and even to shell elements where the drilling +degree of freedom may be singular, which is likely in flat geometries. +xy +y +x +Figure 15-7. Definition of the coordinate system with two vectors. +Origin (0,0,0) +*DEFINE_CPM_BAG_INTERACTION +Purpose: To model energy flow from a master airbag to a slave airbag. The master +must be an active particle airbag and the slave a control volume (CV) airbag converted +from a particle bag. +To track the flow of energy, LS-DYNA automatically determines which vent parts are +common to both airbags. At each time step the energy that is vented through the +common vents is subtracted from the master and added to the slave. In turn, the slave +bag’s pressure provides the downstream pressure value for the master bag’s venting +equation. While this model accounts for energy flow from master to slave it ignores +flow from slave to master. +If CHAMBER is used for slave CV bag, see remark 1. + Card 1 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +Bag ID1 +Bag ID2 +Type +I +I +Default +none +none + VARIABLE +DESCRIPTION +Airbag ID of master CPM particle bag +Airbag ID of slave CV bag switched from CPM bag +Bag ID1 +Bag ID2 +Remarks: +1. Due to the complexity of the bookkeeping, the slave may have several +chambers but only one of the chambers is allowed to interact with the master +bag. This chamber will be searched automatically through the commonly +shared parts. +*DEFINE +Purpose: To define airbag chambers for air particle initialization or chamber +interaction. + Card 1 +Variable +1 +ID +Type +I +Default +none +2 +3 +4 +5 +6 +7 +8 +NCHM +I +0 +Chamber Definition Card Sets: +Add NCHM chamber definition card sets. Each chamber definition card set consists of +a Chamber Definition Card followed by NINTER Interaction Cards. +Chamber Definition Card. + Card 2 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SID1 +SID2 +NINTER +CHM_ID +Type +I +Default +none +I +0 +I +0 +I +0 +Interaction Cards. Add NINTER of these. If NINTER = 0, skip this card. + Card 3 +1 +2 +3 +4 +5 +6 +7 +8 +Variable +SID3 +ITYPE3 +TOCHM +Type +I +I +I +Default +none +none +none +P3 +P1 +Chamber +997 +Chamber 998 +P2 +P4 +Figure 15-8. + VARIABLE +DESCRIPTION +ID +Unique ID for this card +NCHM +Number of chambers defined in this card +SID1 +SID2 +Part set defining all parts that constitute the chamber volume +Part set defining the parts whose shell normals need to be flipped +(eg. separation walls between chambers) +NINTER +Number of vent hole definition for chamber interaction. +CHM_ID +Chamber ID . +SID3 +Set defining interaction between chambers +ITYPE3 +Set type +EQ.0: Part +EQ.1: Part set +TOCHM +The chamber ID of the connected chamber. +*DEFINE +1. Each chamber's volume is calculated based on the part normals pointed +inwards. So SID1 would normally have parts with their shell normals pointing +inwards. But in some cases, parts may be shared by more than one chamber. In +this case, the shell orientation of certain part(s) may need to be flipped for the +other chambers in question. In such cases, SID2 can be used to flip the shell- +normals for specific parts. +*SET_PART_LIST +$# sid + 1 +$# pid1 pid2 pid3 pid4 + 1 2 3 4 +*SET_PART_LIST +$# sid + 20 +$# pid1 pid2 + 1 2 +*DEFINE_CPM_CHAMBER +$# id nchm + 1234 2 +$# sid1 sid2 ninter chm_id + 20 0 1 998 +$# sid3 itype3 tochm + 2 0 997 +$# sid1 sid2 ninter chm_id + 1 20 1 997 +$# sid3 itype3 tochm + 2 0 998 +2. Particles with different chamber ID will not interact in particle to particle +collision. This feature will allow program to distinguish particles separated by +a thin wall. +3. All chambers data are output to lsda binout database. The utility “l2a” can +convert it into abstat_chamber ASCII file and process with lsprepost under +abstat format +*DEFINE_CPM_GAS_PROPERTIES +Purpose: To define extended gas thermodynamic properties + Card 1 +Variable +1 +ID +2 +3 +4 +5 +6 +7 +8 +Xmm +Cp0 +Cp1 +Cp2 +Cp3 +Cp4 +Type +I +F +F +Default +none +none +0. + Card 1 +1 +Variable +μt0 +Type +F +Default +0. +2 +μt1 +F +0. +3 +μt2 +F +0. +F +0. +4 +μt3 +F +0. +F +0. +F +0. +F +0. +5 +6 +7 +8 +μt4 +Chm_ID +Vini +F +0. +I +0 +F +0. + VARIABLE +DESCRIPTION +ID +Unique ID for this card +Xmm +Molar mass +Cp0, …, Cp4 +Coefficients of temperature dependent specific heat with constant +pressure +Cp(T) = Cp0 + Cp1 T + Cp2 T2 + Cp3 T3 + Cp4 T4 +μt0, …, μt4 +Coefficients of temperature dependent Joule-Thomson effect +μt(T) = μt0 + μt1 T + μt2 T2 + μt2 T3 + μt2 T4 +Chm_ID +Chamber ID (remark 1) +Vini +Initial volume for user defined inflator (remark 1) +Example: +*AIRBAG_PARTICLE +$====1====$====2====$====3====$====4====$====5====$====6====$====7====$====8==== + 1010 1 1011 1 0 0.0 0.0 1 + 100000 0 1 300.0 1.0e-04 1 + 1 1 1 + 61 0 1.0 0 0 1 0.0 + 1.0E-04 300.0 -9900 + 651 653 -9910 + 3000001 1.0 +$==================================================== +*DEFINE_CPM_GAS_PROPERTIES +$====1====$====2====$====3====$====4====$====5====$====6====$====7====$====8==== + 9900 2.897E-02 2.671E+01 7.466E-03-1.323E-06 + 9910 4.0E-03 20.79 + -610.63 -0.0926 +Remark: +1.If Chm_ID and Vini are defined. This gas property will be used in the user_ +inflator routine which is provided in the dyn21b.f of general usermat package. +The code will give current chamber volume, pressure, temperature and time step +and expect returning value of change of chamber, burned gas temperature and +mass flow rate to feedback to the code for releasing particles. All state data for +this chamber will be output binout under abstat_chamber subdirectory. +Purpose: To define extended vent hole options +*DEFINE_CPM_VENT + Card 1 +Variable +1 +ID +2 +3 +4 +5 +6 +7 +8 +C23 +LCTC23 +LCPC23 +ENH_V +PPOP +C23UP +IOPT +Type +I +F +I +I +I +F +F +Default +none +none +none +none +none +none +none + Card 2 +Variable +Type +Default +1 +JT +I +0 +2 +3 +4 +5 +6 +7 +8 +IDS1 +IDS2 +IOPT1 +PID1 +IPD2 +VANG +I +I +I +I +I +F +none +none +none +none +none +0. + VARIABLE +DESCRIPTION +ID +C23 +Unique ID for this card +Vent hole coefficient. +parameter. (Default 1.0) + This +is the Wang-Nefske +leakage +LCTC23 +Load curve defining vent hole coefficient as a function of time. +LCPC23 +ENH_V +Load curve defining vent hole coefficient as a function of +pressure. +Enhance venting option. (Default 0). However if Joule-Thomson +effect is considered, the option will set to 1 automatically. +EQ.0: disable +EQ.1: enable +PPOP +Pressure difference between interior and ambient pressure to +open the vent hole. Once the vent is open then it will stay open. +VARIABLE +C23UP +DESCRIPTION +Scale factor of C23 while switching from CPM to uniform +pressure calculation. +IOPT +Directional venting: +EQ.1: +In shell normal +EQ.2: Against shell normal +One-way venting: +EQ.10: In shell normal +EQ.20: Against shell normal +Special vent option:: +EQ.100: Enable compression seal vent. Vent area is adjusted +according to the formula below. See Remark 1. +𝐴vent = max(𝐴current − 𝐴0, 0) +EQ.200: Enable push-out vent. Particle remains active while +going through this external vent within the range of 2 +times of its characteristic length, 𝑙vent. +𝑙vent = √𝐴vent +JT +Include the Joule-Thomson effect. When the Joule-Thomson +effect is enabled ENH_V is automatically set to 1 (enable). +EQ.0: disable +EQ.1: use part pressure +EQ.2: use chamber pressure +IDS1 +IDS2 +IOPT1 +PID1, PID2 +JT's up stream condition part ID/chamber ID +JT's downstream condition part ID/chamber ID +Upstream chamber ID for one-way vent hole. This will help the +code to determine the probability function. +When specified the vent probability function is evaluated from +the difference of local part pressures (between PID1 and PID2) +instead of the usual calculation involving the chamber pressure. +This option is usually used for vents near a long sleeve which +causing unrealistic venting using chamber pressure alone. +VANG +*DEFINE_CPM_VENT +DESCRIPTION +Cone angle in degrees. Particle goes through this vent will be +redirection based on this angle. This option is only valid with +internal vent. +GT.0: cone angle (maximum 270) +EQ.0: disabled (Default) +LT.0: direction follows the vent normal +Remarks: +1. Compression Seal Vent Model. In order to evaluate bag state variables +correctly, the CPM domain needs to be a closed surface for the volume to be +well-defined. If the model contains a flap vent which is free to open and close, +this option will correctly maintain the bag’s integrity. +Example: +*AIRBAG_PARTICLE +$====1====$====2====$====3====$====4====$====5====$====6====$====7====$====8==== + 1010 1 1011 1 0 0.0 0.0 1 + 100000 0 1 300.0 1.0e-04 1 + 1 1 1 + 61 0 -9910 + 1.0E-04 300.0 2.897E-2 2.671E+1 7.466E-3 -1.323E-6 + 1000 1001 4.0E-3 20.79 + 3000001 1.0 +$==================================================== +*DEFINE_CPM_VENT +$====1====$====2====$====3====$====4====$====5====$====6====$====7====$====8==== + 9910 1.0 0 0 1 0.0 + 1 51 2 +*DEFINE +Purpose: Define a curve [for example, load (ordinate value) versus time (abscissa +value)], often loosely referred to as a load curve. The ordinate may represent something +other than a load however, as in the case of curves for constitutive models. +In the case of constitutive models, *DEFINE_CURVE curves are rediscretized internally +with equal intervals along the abscissa for fast evaluation. Rediscretization is not used +when evaluating loading conditions such as pressures, concentrated forces, or +displacement boundary conditions . +The curve rediscretization algorithm was enhanced for the 2005 release of version 970. +In certain cases the new load-curve routines changed the final results enough to disrupt +benchmarks. For validated models, such as barriers and occupants, requiring numerical +consistency, there are keyword options for reverting to the older algorithms. +Available options include: +