bluuebunny/crossref_metadata_2025_split huggingface dataset:
Shaking table tests of a plate‐column structure with semi‐active tuned mass damper
Authors: Majcher Krzysztof 
Published: December 2014

AbstractThis paper presents selected results of experimental tests carried out on the three‐storey plate‐column structure, which is a physical model of a building. On the top floor the semi‐active tuned mass damper (STMD) is installed. That device is a kind of harmonic oscillator with a variable stiffness characteristic. The tuning of STMD is possible in the frequency range from 0 to 5 Hz, which allows to counteract the resonant vibration of plate‐column structure for the three basic frequencies. The model's vibration are kinematically excited by using the earthquake simulator. It is assumed that during an experimental tests the plate‐column structure's vibration are only excited by horizontal component of base motion (dominant influence on building's vibration). The aim of the experimental analysis presented in this paper is to verify the effectiveness of the semi‐active tuned mass damper in vibration's amplitude reduction of the main structure. The tested device is prototype of STMD, which uses a competitive constructional solution of stiffness parameter control. By reason of above, special attention is focused on the testing of vibration eliminator in two aspects: change of stiffness characteristic (the rate of change), and the accuracy of tuning to the resonant frequencies. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermomechanical contact of rubber‐like solids on rough surfaces
Authors: Beyer Robert , Nackenhorst Udo 
Published: December 2014

AbstractThe contact between tires and the rough road surface is characterized by large local deformations of the tread rubber at high frequency, which result from the penetration of the tread blocks by the highest asperities. These deformations have an influence on the overall performance of tires regarding rolling resistance, sustainability as well as noise radiation. As the mechanical behavior of rubber compounds is strongly rate dependent these deformations cause local energy dissipation. The induced temperature increase affects the mechanical properties of the rubber. A description of the interdependence of mechanical and thermal behavior requires the solution of a coupled problem.In this contribution the tread rubber compound is modeled with an incompressible, thermo‐visco‐elastic constitutive law in the regime of finite deformations taking into account internal friction and the Gough‐Joule effect. The thermomechanical coupling is treated with the isothermal operator split scheme. Here, the mechanical subproblem is solved in a first phase at a constant temperature. Within this phase, the rough surface contact problem of the tread block with the road is treated. The road surface is a representation of a measured real road texture, which has been obtained by applying the fast Fourier transform. In the subsequent thermal phase the heat conduction problem is solved. Here, the mechanical dissipation within the bulk material acts as a heat source. The developed algorithm is applied for a detailed study on the thermomechanical effects occurring in the tire‐road contact interface. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Surface Deformation due to Shear and Ploughing in a Halfspace
Authors: Beyer Florian , Willner Kai 
Published: December 2014

AbstractSheet and bulk metal forming are widely used manufacturing methods. The interaction between worktool and workpiece in such a process causes friction which has a remarkable impact on the expended energy of the process. Therefore the influence of friction is important. Friction can be split into shearing and ploughing [1]. Ploughing is the plastic deformation of a soft surface by a hard contact partner. Shear forces are only transferred in the real contact area where material contact occurs. The investigation of the contribution of both ploughing and shearing to the total friction resistance is done with the use of an elasto‐plastic halfspace model. The multiscale character of surfaces demands a fine discretization, which results in numerical effort. While a finite element method takes into account both surface and bulk of the contact partners, the halfspace model only regards the contact surfaces and thereby consumes less computing capacity. In order to identify the friction resistance, two rough surfaces get into contact. After full application of the normal load, the surfaces are moved relatively to each other. New asperities of the contact surfaces get into contact and are plastically deformed. These deformations are used to estimate the ploughing effect in dependency on the relative displacement. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An improved mixed finite element based on a modified least‐squares formulation for hyperelasticity
Authors: Schwarz Alexander , Steeger Karl , Schröder Jörg , Starke Gerhard , Müller Benjamin 
Published: December 2014

AbstractThe present work deals with the solution of geometrically nonlinear elastic problems solved by the least‐squares finite element method (LSFEM). The main goal is to obtain an improved performance and an accurate approximation in particular for lower‐order elements. Basis for the mixed element is a first‐order stress‐displacement formulation resulting from a classical least‐squares method. Similar to the ideas in SCHWARZ ET AL. [1] a modified weak form is derived by the introduction of an additional term controlling the stress symmetry condition. The approximation of the unknowns follows the same procedures as for a conventional least‐squares method, see e.g. CAI & STARKE [2]. The proposed modified formulation is compared to recently developed classical LSFEMs, in order to show the improvement of performance and accuracy. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Deep drawing of a layered composite: material characterization and finite‐element simulation
Authors: Sguazzo Carmen , Harhash Mohamed , Grafenhorst Matthias , Palkowski Heinz , Hartmann Stefan 
Published: December 2014

AbstractComposite materials are widely used in different industrial fields, because of their good formability and their high strength to weight ratio. In the present work a triple‐layered sandwich composite is investigated. Experimental tests at room temperature are carried out for the materials constituting the composite. A finite element model of a deep‐drawing process of the composite is performed, where a finite strain constitutive model for the metal part, with material parameters calibrated to uniaxial tensile tests, has been implemented. Experimental results are compared to the numerical simulations in view of validation purposes. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Identification of the lamination stack's behavior simulated with a multi‐scale homogenization using a progressive contact formulation
Authors: Luchscheider Vera , Maidorn Mischa , Willner Kai 
Published: December 2014

AbstractThe influence of the lamination stack on the mechanical behavior of an electrical motor is significant, especially for lightweight designs. Information about the stack's behavior is relevant for a proper calculation of the whole motor. This behavior is dependent on the contact between the single sheets resulting from the roughness and the behavior of the roughness peaks. The normal behavior is an elasto‐plastic and progressive one, which results mainly of the number of roughness peaks in contact. Whereas the tangential micro‐slip behavior is dependent on the single contacts and the friction coefficient. Both behaviors can be described by models and thus it is possible to calculate the behavior of a whole stack using an homogenization based on representative volume elements. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Energy harvesting by coupled oscillators forced by excitations with harmonic and random components
Authors: Litak Grzegorz 
Published: December 2014

AbstractWe examine an energy harvesting system of two magnetopiezoelastic oscillators coupled by electric circuit and driven by a combination of harmonic and stochastic ambient disturbances. The effects of synchronization and escape from a single potential well are discussed. In the system with relative mistuning in the stiffness of the harvesting oscillators, we show the dependence of the voltage output for different noise levels and excitation frequency. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Untersuchung von Einflussparametern auf das Phänomen der Regen‐Wind induzierten Schwingungen
Authors: Seidel Christian , Dinkler Dieter 
Published: December 2014

AbstractRegen‐Wind induzierte Schwingungen sind ein hydroaeroelastisches Schwingungsphänomen, welches bei gleichzeitigem Auftreten von Regen und Wind an geneigten Kabeln, Hängern oder Seilen entstehen kann. Das Phänomen tritt bei turbulenzarmem Wind mit Geschwindigkeiten von 5 bis 30 m/s und Reynoldszahlen im unterkritischen und kritischen Bereich (5 · 104 bis 3 · 105) auf. In der Literatur werden Schwingungen sowohl in Längs‐ als auch in Querrichtung des Windes mit Amplituden bis zu 1,73 m und mit Frequenzen bis zu 9 Hz beschrieben. Der Wind kommt beim Auftreten der Schwingungen meist aus ausgezeichneten Anströmrichtungen zur Zylinderlängsachse. Die untersuchten Zylinderstrukturen sind i.a. geneigt und besitzen Durchmesser von 4 bis 25 cm. Neben einer geringen Dämpfung weisen alle Zylinderstrukturen eine glatte Oberfläche (i.a. HDPE‐Überzüge) auf. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Generalized distortional hardening in a thermomechanically coupled framework
Authors: Bartels Alexander , Mosler Jörn 
Published: December 2014

AbstractIn many metals like aluminum the evolution of the microstructure leads to an evolution of the macroscopic yield surface. Clearly, isotropic and kinematic hardening models cannot capture this effect realistically. For that purpose, a new generalized distortional hardening model is proposed. This novel approach belongs to the class of so‐called generalized standard materials and is thermodynamically consistent. Although the approach is relatively simple, it shows several advantages like yield surface convexity and yield limit saturation. This novel model is embedded into a thermomechanically coupled finite strain framework. Several numerical simulations show the predictive capabilities. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Compendium on the Principle of the Minimum of the Dissipation Potential for Non‐Isothermal Processes
Authors: Junker Philipp , Makowski Jerzy , Hackl Klaus 
Published: December 2014

AbstractIn this paper we present a compendium of the original paper “The Principle of the Minimum of the Dissipation Potential for Non‐Isothermal Processes”, published in Continuum Mechanics and Thermodynamics [1]. There, a contribution to the methodology of material modeling was introduced by presenting a potential‐based approach for non‐isothermal processes. It was based on the principle of the minimum of the dissipation potential which was used previously only for isothermal material models. In contrast to the principle of maximum dissipation, the presented procedure resulted in mathematically simplified equations. Due to its potential character, the inclusion of constraints was very simple. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Configurational Forces in Cutting Processes of Microstructured Titanium
Authors: Lohkamp Richard , Kuhn Charlotte , Müller Ralf , Aurich Jan C. , Schneider Frank 
Published: December 2014

AbstractThe micro cutting process of microstructured material is influenced by the heterogeneity of the microstructure. In case of cp‐titanium an hcp crystal structure is present. Therefore the material response is described with elastic anisotropy and crystal plasticity with the prismatic and basal slip systems of cp‐titanium. Also self and latent hardening are considered. The rate dependency is taken into account by a visco‐plastic evolution law. In order to investigate a micro cutting process the concept of configurational forces for standard dissipative media is used. Within the finite element method an example illustrates the effects of the heterogeneity and the grain boundary on the configurational force. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On physics‐based crystal plasticity models: Application to virtual material testing of sheet metals
Authors: Pagenkopf Jan , Baiker Maria , Helm Dirk 
Published: December 2014

AbstractIt is possible to pursue a multi‐scale modeling approach for sheet forming simulations by applying the concept of virtual material testing to determine the yield surface from the microstructure of a given material. Full‐field simulations with phenomenological crystal plasticity models are widely used for this kind of investigations. However, recent developments focus on incorporating physical quantities like dislocation density into these models. In this work, a dislocation density based crystal plasticity model is used to investigate the plastic anisotropy of the deep drawing steel DC04. In particular, we focus on the prediction of R‐values, which can be used to calibrate macroscopic plasticity models. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Distribution of dislocation density and residual stresses in plastically deformed specimens: numerical studies
Authors: Shutov A. V. , Silbermann C. , Ihlemann J. 
Published: December 2014

AbstractA two‐scale approach to the simulation of mechanical properties of metallic materials is considered. On the macroscopic level, the material behavior is described by a phenomenological model of finite strain viscoplasticity with nonlinear kinematic hardening. In particular, the process‐induced plastic anisotropy is captured by backstresses. On the microstructural level, the so called “load path sensitive two‐population dislocation cell model” is implemented. It describes an evolving dislocation cell structure with dislocation populations for dislocation cell walls and the cell interior. Owing to the coupling with the phenomenological plasticity model, it can describe the evolution of the dislocation densities depending on the load path. The applicability of the multiscale approach to the FEM simulation of severe plastic deformation processes such as Equal Channel Angular Pressing is demonstrated. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Extension of a uniaxial model with Payne effect by the description of the Mullins effect and generalization to three dimensions
Authors: Freund Michael , Rabkin Michael , Ihlemann Jörn 
Published: December 2014

AbstractIn order to simulate the Payne effect of filler reinforced elastomers under cyclic loading a one‐dimensional material model for uniaxial tension and compression has been developed. It is able to cover the decrease of the dynamic stiffness with increasing loading amplitude (Payne effect) as well as the dependency of the stiffness on the static preload. The model has been extended by the description of the Mullins effect using modified strains for the computation of the uniaxial stresses. The subsequent generalization to a fully three‐dimensional constitutive model for the finite element method is achieved by using the concept of representative directions in form of a numerical integration of uniaxial stresses over a unit sphere. Finally, the generalized model is validated by means of experimental data of different rubber materials and testing procedures. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the parameter identification of visco‐hyperelastic material models for adhesive tapes
Authors: Kröger Nils Hendrik , Juhre Daniel 
Published: December 2014

AbstractIn this work we investigate the performance of a visco‐hyperelastic material model to predict the time‐dependent deformation behaviour of highly elastic adhesives. The model is based on the hyperelastic Arruda‐Boyce model with a Prony series approach. The parameter identification is conducted for fixed relaxations times which are predicted via evaluating an integral ansatz for the shear modulus. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On operator split technique for the time integration within finite strain viscoplasticity in explicit FEM
Authors: Silbermann Christian B. , Shutov Alexey V. , Ihlemann Jörn 
Published: December 2014

AbstractIn this contribution, the operator split technique is applied to the time integration within viscoplasticity for explicit FEM. As an example, the finite strain viscoplastic material model of Shutov and Kreißig is analyzed. In the new solution scheme, some evolution equations are solved using an explicit update formula for implicit time stepping. The solution procedure is split into three steps: an elastic predictor and two viscoplastic corrector steps. Aspects of accuracy and stability of the algorithm are discussed. As shown, the proposed method is superior compared to a fully explicit integration of evolution equations. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A finite elasto‐plasticity model for thick adhesive layers based on generalized stress‐strain measure
Authors: Kieser Florian , Klinkel Sven 
Published: December 2014

AbstractThe collective term adhesives includes a wide field of materials with a diversity of different material properties. Regarding high‐strength adhesives, the assumption of small strains often holds according to their brittle behavior. The experience with plasticity models based on the additive decomposition into elastic and inelastic strains indicates an appropriate approach to characterize such materials. In some cases, due to a more ductile material response, the assumption of infinitesimal strains is not valid anymore. In particular this is the case for high‐strength adhesives with additives like rubber. But ductile behavior is also observed for specific stress states in one adhesive, e.g. when the behavior for tensile is quite brittle while large shear‐strains could appear. The objective of this work is to overcome the theoretical restriction of small strains and to archive the practical experiences. For the failure criterion two stress invariants are used, which involves the hydrostatic pressure as well as the deviator stress state. The flowrule is introduced for the evolution of the inelastic variables. Herein the flow rule has to be of non‐associated type to ensure the thermodynamical consistency of the model. The plasticity model also includes hardening as well as softening. The presented finite strain model makes use of the fact that the eigenvalues for Green‐Lagrange strains and generalized strains are the same. Thus the limit of applicability is extended to finite strains. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On effects of discretization and the selection of constitutive equations on stability of continua
Authors: Béda Peter 
Published: December 2014

AbstractIn classical continuum mechanics the set of basic equations consists of the equation of motion, the kinematic equation and the constitutive equations. The study concentrates on constitutive modeling and the effects of discretization on stability problems. The method of investigation is analytic, the spectra of linear mapping operators of continuous and discrete dynamical systems are studied. As results cases are found, when a hidden incursive nature of a material model leads to unstable behavior of the continuum. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An anisotropic large strain plasticity model for multifilament yarns
Authors: Donner Hendrik , Ihlemann Jörn 
Published: December 2014

AbstractImportant industrial rubber components like tyres, driving belts and air springs are usually reinforced by twisted polymer cords. A cord itself is a twisted structure of several multifilament yarns. Each yarn is a twisted strand consisting of a large number of polymer filaments. In this work, an anisotropic large strain plasticity model is presented which captures the yarn's filament structure and frictional behaviour. The material model is implemented in Abaqus adopting its user subroutine UMAT and validated by a simulation of a cord's twisting process and the comparison with microscope images. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A macroscopic consitutive model on induced anisotropy for polymers with weighting functions
Authors: Dammann Christian , Mahnken Rolf 
Published: December 2014

AbstractThe alignment of polymer chains is a well known microstructural evolution effect due to straining of polymers. This has a drastic influence on the macroscopic properties of the initially isotropic material, such as a pronounced strength in the loading direction of stretched films. Experiments on strain induced anisotropy at room temperature are analyzed by optical measurements. For modeling the effect of strain induced anisotropy a macroscopic constitutive model is presented. As a key idea, weighting functions are introduced to represent a strain‐softening/hardening‐effect to account for induced anisotropy. These functions represent the ratio between the total strain rate and a structural tensor. In this way, material parameters are used as a sum of weighted direction related quantities. In the finite element examples we simulate the cold‐forming of amorphous thermoplastic films below the glass transition temperature subjected to different re‐loading directions. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multi‐scale modeling of double network hydrogels
Authors: Külcü İsmail Doğan , Dargazany Roozbeh , Itskov Mikhail 
Published: December 2014

AbstractA double network hydrogel (DN gel) is a class of elastomeric gels formed by polyelectrolyte and neutral polymer networks. The DN gel is the toughest material among the conventional hydrogels. It shows inelastic features such as necking instability [1] and the stress softening [2], similar to that one known in elastomers. In this contribution, we purpose a micro‐mechanically motivated model to characterize relation between internal damage and inelastic deformations in the DN gel. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling of Single Crystal Magnetostriction Based on Numerical Energy Relaxation Techniques
Authors: Buckmann Karsten , Kiefer Björn , Bartel Thorsten , Menzel Andreas 
Published: December 2014

AbstractIn this work, an incremental energy minimization technique is proposed to simulate the magnetomechanically‐coupled, nonlinear, anisotropic and hysteretic response of single crystalline magnetic shape memory alloys (MSMA). The model captures the three key physical mechanisms that cause this characteristic behavior, namely the field‐ or stress‐induced martensite variant reorientation (twin boundary motion), magnetic domain wall motion, and local magnetization rotation, through an (incremental) energy minimizing evolution of internal state variables. Representative numerical response predictions are presented, compared to experimental observations, and discussed with respect to the associated microstructure evolution. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling and Simulation of Rate‐Dependent Magneto‐Active Polymers
Authors: Haldar Krishnendu , Kiefer Bjoern , Menzel Andreas 
Published: December 2014

AbstractIn the present work, the magneto‐viscoelastic behavior of MAPs is studied by a thermodynamically consistent constitutive model. A finite deformation based framework of nonlinear magneto‐viscoelastic coupling is introduced with a multiplicative decomposition of the deformation gradient. The viscosity is captured by evolution equations of the internal variables introduced. We propose energy functions for pure magnetic and magneto‐mechanical coupling such that saturation behavior of the magnetostriction and magnetization is captured. After having established the general framework, the model is studied for homogeneous deformations for the purpose of a least‐square‐based parameter identification from experimental data. The model predictions of non‐linear magneto‐mechanical responses with strong rate and field dependency are presented. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)