bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermoplastics under Long‐Term Loading: Experiments and Viscoelastic‐Viscoplastic Modeling
Authors: Zerbe Patrick , Schneider Benjamin , Moosbrugger Egon , Kaliske Michael 
Published: October 2015

AbstractThe behavior of polyoxymethylene, a semicrystalline thermoplastic, with respect to mechanical long‐term loads is studied. Experiments demonstrate the creep behavior for constant load and also for cyclic unloading. The latter shows partial time‐dependent strain recovery during unloading and an extended lifetime. Based on the experimental results, a viscoelastic‐viscoplastic‐damage material model for finite strains is proposed. Numerical simulations are compared to the experimental results demonstrating the model's capabilites and limitations. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonlinear numerical simulation of ferroelectric‐ferromagnetic multifunctional composites
Authors: Avakian Artjom , Ricoeur Andreas 
Published: October 2015

AbstractThe theoretical background of nonlinear constitutive multifield behavior is presented. Nonlinear material models describing the ferroelectric or ferromagnetic behaviors are presented. Both physically and phenomenologically motivated constitutive models have been developed for the numerical calculation of the nonlinear magnetostrictive and ferroelectric behaviors. On this basis, the polarization in the ferroelectric and magnetization in the ferromagnetic respectively magnetostrictive phases are simulated and the resulting effects analyzed. The developed tools enable the prediction of the electromagnetomechanical properties of smart multiferroic composites and supply useful means for their optimization. Goals are to improve the efficiency of ME coupling and to reduce damage associated with the poling process. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Correction of Characteristics of Subsystems of Torsionally Vibrating Complex Mechatronic Systems as an Introduction to Solution of Their Inverse Task
Authors: Buchacz Andrzej 
Published: October 2015

AbstractIn this paper the analysis of torsionally vibrating subsystem of complex mechanical and mechatronic systems by using the the exact and approximate methods were the main purposes to solve the task of assignment of frequency‐modal analysis and characteristics of mechatronic system. The characteristic of the elementary subsystems using the exact and approximate methods has been determined according to accepted frequencies and the correction coefficient. The frequencies were chosen from the spectrum in which the synthesis of complex systems will be conducted. It is very important that the difference of flexibility values in the spectrum was minimal. The coefficient of the correction has been determined according to the flexibility values of chosen points and it is equal to quotient of flexibility calculated using the exact method across the flexibility delivered by using the approximate method. The coefficient of the correction is the zero‐dimensional quantity. After determination of the correction coefficient the medium value which has been afterwards considered in correlation of dynamic characteristics has been calculated. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Intrinsic symmetries in constitutive modeling of magneto–elastic materials
Authors: Dobovšek Igor 
Published: October 2015

AbstractWe consider a class of non‐dissipative materials whose constitutive equations are derived from a suitably constructed thermodynamic potential function. The Gibbs energy relation is introduced as a function of stress, strain, magnetic field, magnetization, and temperature. By minimization with respect to the chosen subset of independent variables we derive the corresponding set of constitutive equations. The chosen form of the free energy function leads to the linear elastic and nonlinear ferromagnetic coupling where non‐linearity emerges in terms associated with the strength of magnetization. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Application and modification of the POD method and the POD‐DEIM for model reduction in porous‐media simulations
Authors: Fink Davina , Ehlers Wolfgang 
Published: October 2015

AbstractResearchers with a continuum‐mechanical background typically use a multi‐phasic and multi‐component modelling approach for materials with a saturated porous microstructure. Therefore, the mechanical behaviour is considered in a continuum‐mechanical manner and solved using the finite‐element method (FEM). The developed models need to be complex enough to capture the relevant properties of the considered materials, what often results in expensive simulations with a very large number of degrees of freedom (DOF). The aim of the present contribution is to reduce the computing time of these simulations through model‐reduction methods, while the accuracy of the solution needs to be maintained. Therefore, the method of proper‐orthogonal decomposition (POD) for linear problems and the discrete‐empirical‐interpolation method (DEIM) in combination with the POD method (POD‐DEIM) for nonlinear problems are investigated. Using the POD method, a given data set is approximated with a low‐dimensional subspace. To generate this data set, the vector of unknowns of the FE simulation is stored in a pre‐computation in the full (unreduced) system in each time‐step (so‐called “snapshots” of the system). Dealing with porous‐media problems, the primary variables are the solid displacement, the pore pressure and, depending on the particular problem, other primary variables. Following this, the primary variables have entries with very huge differences in their absolute values. As a result, non‐negligible rounding errors may occur when applying the POD method. To overcome this problems, modifications of the classical POD method need to be performed for such problems. The present contribution discusses this issue and presents results for the reduced simulations of porous media. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simulation of Vortex‐Induced Oscillations within a Shear Thinning Liquid
Authors: Gundlach Janto , Schlosser Alexander , Wünsch Olaf 
Published: October 2015

AbstractThe present work discusses the impact of nonlinear shear thinning in a viscous fluid flow on the vibration behavior of an elastic bar. In the process numerical simulations have been performed concerning a well‐known FSI benchmark geometry. In contrast to past investigations a non‐Newtonian liquid of the Carreau‐Yasuda type is used as fluid component. In order to accomplish the coupling between the liquid and the solid domain, an approach using quasi‐Newton iterations is applied. In a parameter study material and geometrical parameters are changed. The solutions show distinct deviations compared to results obtained with a Newtonian liquid. These differences emphasize the nonlinearity of the shear thinning material model. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling a Halfspace with Tunnel using a Coupled Integral Transform Method – Finite Element Method Approach
Authors: Hackenberg Manuela , Müller Gerhard 
Published: October 2015

AbstractVibrations that are excited by moving trains inside a tunnel are regularly transmitted via the tunnel and the surrounding soil and often perceived at the surface. In order to assess the effects of the arising vibrations and to be able to model possible mitigation measures, a suitable model of the system is necessary. In this paper, a coupled approach is presented, where the emission system of an underground tunnel is modeled using the Finite Element Method while the transmission medium of the soil is described by Integral Transform Methods. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermo‐mechanical modelling of cellular ceramic composites by a multiphase approach of porous media
Authors: Jung Anne , Diebels Stefan 
Published: October 2015

AbstractRefractory materials have a wide range of applications in the steel‐making industry for example as lining of furnaces, oxygen converters or for ladles. Often, magnesia carbon bricks (MgO‐C) are used. These are made of a periclase phase (MgO) with carbon inclusions and pores. In their applications, refractories are subjected to thermal and mechanical loads causing damage. The thermo‐mechanical behaviour of MgO‐C composites and hence their thermal stability could be improved significantly using cellular MgO‐C composites based on carbon foams [1, 2]. The present contribution focuses on the development of a fully coupled phenomenological thermo‐mechanical continuum model based on the theory of porous media (TPM) with a new kinematic coupling of the displacement field of all constituents. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling, Simulation and Parameter Identification for Rate‐Dependent Magnetoactive Polymer Response
Authors: Kiefer Bjoern , Haldar Krishnendu , Menzel Andreas 
Published: October 2015

AbstractA finite deformation framework for nonlinear magneto‐viscoelasticity is introduced and applied to the constitutive and structural modeling of magnetoactive polymer (MAP) response. In this thermodynamically‐consistent formulation the free energy function consists of purely elastic, purely magnetic and coupling contributions, where the rate‐dependence is fully attributed to the non‐magnetizable matrix material. The model consistently accounts for saturation in the magnetic as well as the magnetostrictive behavior. The identification of material parameters from experimental data is briefly described. Finally, a finite element model for the large strain magneto‐mechanical problem is established and tested considering MAP behavior. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A constitutive and damage model for high cycle fatigue of tetragonal ferroelectrics
Authors: Lange Stephan , Ricoeur Andreas 
Published: October 2015

AbstractReliability and life time of smart materials are crucial features for the development and design of actuator and sensor devices. Being widely used and exhibiting brittle failure characteristics, ceramic ferroelectrics are of particular interest in this field. Due to manifold interactions of the complex nonlinear constitutive behavior on the one hand and the damage evolution in terms of microcrack growth on the other, modeling and simulation are inevitable to investigate influence parameters on strength, reliability and life time. A condensed approach is used for the simulations considering just one characteristic point in the material, nonetheless accounting for polycrystalline grain interactions. On this basis, a model to predict the life time in terms of high cycle fatigue under electromechanical loading conditions is introduced. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hydroelastic stability of multi‐plate structures interacting with flowing fluid
Authors: Bochkarev Sergey , Lekomtsev Sergey , Matveenko Valery 
Published: October 2015

AbstractThe paper is concerned with the finite‐element analysis of natural vibrations and hydroelastic stability of two parallel plates interacting with liquid. The influence of the fluid layer thickness on the eigenfrequencies, vibration modes and hydroelastic stability boundary are estimated based on the results of numerical solution of some example problems. The numerical investigation substantiates the existence of various instability modes, the onset of which depends on the combinations of kinematic boundary conditions specified at the plate ends. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Shock structure for macroscopic multi‐temperature model of binary mixtures: comparison with kinetic models
Authors: Madjarević Damir 
Published: October 2015

AbstractThe present study deals with the shock wave profiles in the macroscopic multi‐temperature (MT) model of binary gaseous mixtures. For that purpose we have adopted the hyperbolic model developed within the framework of extended thermodynamics [1] in which we include viscosity and thermal conductivity to eliminate restriction on parameters. This allows us to compare our results with more sophisticated kinetic solutions, which were computed for hypothetic mixtures of gases [2]. Numerical implementation of the MT model is considerably simpler than the one for Boltzmann equations for mixtures or the direct simulation Monte Carlo method (DSMC). (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reduction Approaches for Thermogasdynamic Lubrication Problems
Authors: Mahner Marcel , Lehn Andreas , Schweizer Bernhard 
Published: October 2015

AbstractGas thrust bearings are often used in low‐load applications, e.g. in air cycle machines, in micro gas turbines or in rotor systems for fuel cell applications, to support a shaft in axial direction. The pressure and temperature distribution in a gas thrust bearing pad are described by the generalized Reynolds equation according to Dowson and the 3D energy equation. In this paper, two different approaches are presented in order to reduce the dimension of the governing nonlinear integro‐differential equation system and in order to stabilize the solution process. In the first reduction approach, the temperature in the fluid is averaged across the fluid film according to Lee and Kim. In the second approach, Legendre polynomials are used to approximate temperature, density and fluidity across the fluid film according to Elrod, Brewe and Moraru. The reduction techniques are compared with respect to numerical efficiency, accuracy and convergence behavior. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling of electrodynamic‐mechanical coupling phenomena in smart magnetoelectroelastic materials
Authors: Merkel Eugen , Ricoeur Andreas 
Published: October 2015

AbstractThe coupling of electric, magnetic and mechanical phenomena may have various reasons. The famous Maxwell equations of electrodynamics describe the interaction of transient magnetic and electric fields. On the constitutive level of dielectric materials, coupling mechanisms are manyfold comprising piezoelectric, magnetostrictive or magnetoelectric effects. Electromagnetically induced specific forces acting at the boundary and within the domain of a dielectric body are, within a continuum mechanics framework, commonly denoted as Maxwell stresses. In transient electromagnetic fields, the Poynting vector gives another contribution to mechanical stresses. First, a system of transient partial differential equations is presented. Introducing scalar and vector potentials for the electromagnetic fields and representing the mechanical strain by displacement fields, seven coupled differential equations govern the boundary value problem, accounting for linear constitutive equations of magnetoelectroelasticity. To reduce the effort of numerical solution, the system of equations is partly decoupled applying generalized forms of Coulomb and Lorenz gauge transformations [1,2]. A weak formulation is given to establish a basis for a finite element solution. The influence of constitutive magnetoelectric coupling on electromagnetic wave propagation is finally demonstrated with a simple one‐dimensional example. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Variational Formulation and Numerical Implementation of Diffusion in Hydrogels at Finite Strains
Authors: Nateghi Aref , Mauthe Steffen , Miehe Christian 
Published: October 2015

AbstractHydrogels are polymeric materials with a cross‐linked network which can absorb water. Due to their bio‐compatibility, hydrogels have many applications in biology and medicine. Recently modeling the mechanical behavior of hydrogels has attracted a great deal of attention among researchers, see e.g., [1] and [2]. Following our previous works [3], [4] and [5] we now present a variational framework for swelling phenomenon in hydrogels. The variational formulation of the problem can be done using a saddle‐point principle or a minimization principle. Saddle‐point principle has to fulfill the Ladyzhenskaya‐Babuška‐Brezzi (LBB) condition in order to lead to a stable finite element scheme. The key aspect of our proposed minimization principle is its advantage with regard to an unconstrained fem implementation. In this work we aim to compare the numerical performance of these two variational formulations for swelling of hydrogels. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling of the Crosstalk Phenomenon by Bilateral Coupling of the Non‐Stationary Maxwell Equations and the Circuit Equations
Authors: Niroomand Rad Helia , Steinbrecher Andreas 
Published: October 2015

AbstractIn this paper, we introduce a general modeling approach for the crosstalk phenomenon within electro‐magnetic systems. We model the phenomenon by bilateral coupling of two sets of differential equations, namely non‐stationary Maxwell equations and circuit equations. Considering these two sets of equations as input‐output systems, the bilateral coupling approach connects the output of one system to the input of the other system and conversely, via coupling and re‐coupling relations. The coupling of these two sets leads to a set of partial differential‐algebraic equations modeling the crosstalk phenomenon. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Velocity Vector Field Optimization in Bioventing
Authors: Notarnicola Filippo 
Published: October 2015

AbstractBioventing is a technology used to remove some kinds of pollutants from the subsoil and it is based on the capability of some bacteria species to biodegrade contaminants. The biochemical reaction requires, among other things, oxygen and, therefore, oxygen is inflated into the subsoil by wells. The mathematical model describes the movement of the different fluids which are present in the subsoil – air, water, pollutants, oxygen and so on – and the bacteria population dynamics. The presence of source reactive terms in the continuity equations allows the contaminant biodegradation to be described.The design of a subsoil decontamination intervention concerns bioavailability problems and, in particular, the oxygen concentration. Therefore, in order to enhance the biodegradation phenomenon, the optimization of the subsoil oxygen velocity field in the polluted area is required, by an appropriate choice of the well positions and of the well air inflating rates. In mathematical terms, the goal is to obtain the decontamination of the subsoil with an optimal value of an objective function by acting on some control variables which, in this case, are the well positions and the inflating rates. In this paper several kind of objective function are proposed. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Static condensation within the context of multifield elastoplasticity
Authors: Schröder Bettina , Kuhl Detlef 
Published: October 2015

AbstractIn the present paper a multifield approach towards ideal elastoplasticity is presented and its numerical implementation is touched. Furthermore, the strategy of static condensation is applied to this ansatz. With the help of an axisymmetric model problem its realization is demonstrated and compared to the pure multifield approach. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling of thermo‐electro‐mechanical coupling effects in ionic electroactive polymers within the Theory of Porous Media
Authors: Serdas Serdar , Bluhm Joachim , Schröder Jörg 
Published: October 2015

AbstractIn this contribution, a multiphase model will be presented in order to simulate ionic electroactive polymers (EAPs). The considered material model is developed within the framework of the Theory of Porous Media (TPM) which consists a thermo‐electro‐mechanical coupling. For the description of the model, a thermodynamically consistent formulation in consideration of the electrostatic forces and the fluid pressure will be derived. The presented model includes a charged polymer (solid) saturated by an electrolyte solvent (fluid). A boundary value problem (plate with a hole) is given. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Isogeometric analysis of surface elasticity: a comparison with isoparametric FEM
Authors: Stein Peter , Xu Bai‐Xiang 
Published: October 2015

AbstractWe report here on the isogeometric treatment of surface‐elastic effects and compare the results obtained from Finite Element simulations and Isogeometric Analysis. As expected, the latter delivers smoother solutions than a standard finite element approach. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Validation with Numerical Simulations of a Simplified Model of a Hybrid Rocket Motor
Authors: Frunzulica Florin , Stoia‐Djeska Marius , Mingireanu Florin 
Published: October 2015

AbstractThe hybrid propulsion offers some remarkable advantages like high safety and high specific impulse and thus it is considered a promising technology for the next generation launchers and space systems. The purpose of this work is to validate through numerical simulations a design tool for hybrid rocket motors (HRM). (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Critical velocities for flow induced vibrations of a U‐shaped belt
Authors: Strecha Johannes , Steinrück Herbert 
Published: October 2015

AbstractTwo excitation mechanisms for flow induced vibrations of a U‐shaped belt are described. Firstly, the belt can be excited by vortices forming in the cavity of the U. This mechanism is relevant at low reduced (dimensionless) flow velocities. Secondly, an excitation through the so called motion induced vortices can occur at larger reduced velocities. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The electrocaloric effect in ferroelectrics: nonlinear modeling and simulation
Authors: Wingen Marius , Ricoeur Andreas 
Published: October 2015

AbstractIn this paper, the theoretical background of a physically based constitutive model is presented. In addition to the nonlinear ferroelectric behavior, the model considers the nonlinear coupling of thermal and electromechanical fields. Results are presented in terms of a simple analytical solution for a single domain configuration. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermo‐mechanical computation of inelastic pavement structures under rolling tire loads
Authors: Wollny Ines , Hartung Felix , Kaliske Michael 
Published: October 2015

AbstractA realistic and numerically efficient computation of the tire‐pavement interaction is essential for the investigation of the structural behavior of pavements under rolling tire load as base of the development of more durable pavement structures. The paper presents a thermo‐mechanical coupled simulation model based on an Arbitrary Lagrangian Eulerian (ALE) formulation that considers the inelastic and temperature dependent material properties of asphalt. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phase field simulation of the intercalation‐induced stresses in the hyperelastic solids via isogeometric analysis
Authors: Zhao Ying , Stein Peter , Xu Bai‐Xiang 
Published: October 2015

AbstractIn this work the Cahn‐Hilliard‐type diffusion in a hyperelastic solid will be studied and simulated using isogeometric analysis. The Cahn‐Hilliard model is employed to account for the phase segregation phenomenon, in which a fourth‐order partial differential operator exists. In order to deal with this high‐order operator, isogeometric analysis is applied. Finally, simulation results of a disc is given. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)