bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Internal Actuator Properties of Active Anti‐Roll Systems on the Vehicle Driving Behaviour
Authors: Mirwaldt Thomas , Harrer Manfred , Eberhard Peter 
Published: December 2012

AbstractThe application process of active anti‐roll systems can be supported by the implementation of numerical optimization routines. The optimization objectives evaluate the handling and comfort vehicle behaviour and are calculated online from vehicle measurement variables. A model‐based analysis illustrates the influence of the actuator properties on these optimization objectives. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparative study on control concepts of a robot manipulator with multiple‐link/joint flexibilities
Authors: Staufer Peter , Gattringer Hubert , Bremer Hartmut 
Published: December 2012

AbstractIf one is dealing with active vibration suppression on a highly nonlinear flexible system, various techniques are needed. On the one hand a suitable dynamic model of the system is required. And on the other hand intelligent model based control concepts are necessary for active vibration damping. We deal with a basic model, where the flexibilities are approximated with linear springs and dampers, a so called lumped element model (LEM). For the control design we propose a control structure with two degrees of freedom (2DoF) for solving the tracking problem, based on the LEM. Such an approach allows designing the feedforward part independently of the feedback part. Hereby the feedforward control is based on the flatness approach, while for the feedback control several strategies are studied using acceleration‐ and gyrosensor‐measurements. The contribution is completed with a validation by measurements from a very fast trajectory on an articulated robot with two flexible links and three elastic joints. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Convergence Study of Explicit Co‐Simulation Approaches with Respect to Subsystem Solver Settings
Authors: Schmoll Robert , Schweizer Bernhard 
Published: December 2012

AbstractCoupling different subsystem simulators can be accomplished by a co‐simulation [1, 2]. For this purpose, the subsystem solvers are coupled by appropriate input and output variables. In order to analyze the stability of the coupled simulation, not only the coupling technique must be taken into account, but also the subsystem integrators. On the one hand, the stability of the co‐simulation is influenced by the extrapolation of the coupling variables and by the macro‐step size. On the other hand, the numerical errors arising from the subsystem solvers may directly affect the coupled simulation. The focus of this paper lies on the question, how the subsystem solvers influence the co‐simulation. Therefore, numerical studies regarding the numerical stability and the convergence order have been carried out by using a co‐simulation test model. We restrict ourselves to explicit co‐simulation techniques, based on a zero‐stable applied‐force coupling approach. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental and theoretical investigation on soft tissue remodeling enhanced by cell activity
Authors: Yi Jeong‐Hun , Stoffel Marcus , Weichert Dieter , Nebelung Sven , Rath Björn 
Published: December 2012

AbstractThe aim of the present work is to investigate the remodeling phenomenon of a cell‐seeded tissue. In experiments, a cell seeded condensed collagen gel is mechanically stimulated in a bioreactor for four weeks, after which the specimen is tested in compression to measure its change of stiffness. The change, regarded as remodeling, is assumed to be the result of newly synthesized collagen type II; a constitutive equation is proposed for the remodeling effect. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Biphasic Approach for the Simulation of Growth Processes in Soft Biological Tissues Incorporating Damage‐Induced Stress Softening
Authors: Schmidt Thomas , Balzani Daniel , Ricken Tim , Werner Daniel 
Published: December 2012

AbstractIn this contribution a coupled material framework is presented, which considers the effects of damage and growth in soft biological tissues. The tissue is described as a porous medium by taking into account a solid and a fluid phase. The fluid phase is assumed to carry nutrients supplying growth of the solid phase. The latter one is described as a fiber‐reinforced material, where a damage variable is introduced for the fiber part of the associated free energy function. The performance of the proposed model is demonstrated in a finite element analysis of a simplified human heart model. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Study of the biomechanical behaviour of structurally stable/unstable motion segments of the sheep spine
Authors: Strampe Malte , Stoffel Marcus , Weichert Dieter , Sellei Richard Martin , Pape Hans‐Christoph 
Published: December 2012

AbstractThe effects of damage of intervertebral discs on their biomechanical behaviour and the factors favouring the progression of instability are studied. Healthy and damaged movement segments are analyzed experimentally and numerically. The aim is to represent and predict the effects of tissue damage and changes in the spine by comparison with healthy segments. Since the intervertebral disc acts as a mechanical damper, relaxation tests are performed in addition to pressure experiments. The experiments are carried out in a bioreactor with tempered nutrient solution. A cultivation period in the bioreactor allows detecting cell viability, solute diffusion rates and gene expression of the discs. Numerically, the nonlinear, viscoelastic, anisotropic and diffusion‐dependent behaviour of the intervertebral disc is modelled with the FE‐program Abaqus, using a modular material law as a UMAT subroutine. With the measurement results, the relevant parameters can be determined so that the mechanical behaviour of intervertebral discs can be simulated. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A biphasic transverse isotropic FEM model for cartilage
Authors: Albrecht Daniel , Ricken Tim , Pierce David M. , Holzapfel Gerhard A. 
Published: December 2012

AbstractArticular cartilage is a viscoelastic, two‐phase and fiber‐strengthen tissue; it consists of a solid and a fluid phase. We describe this tissue using the Theory of Porous Media (TPM). Some simulation results are shown. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vibrating Portable Machine‐Tools Acting on Human Operator
Authors: Gligor Anamaria , Ţepeç‐Bobescu Alina‐Sabina , Arghir Mariana 
Published: December 2012

AbstractThis paper will be a short presentation of the specialized literature and international standards about the importance of vibration action of portable machine tools on human body and particularly on the hand‐arm system. Exposure to harmful vibrations can lead to health problems and disorders, especially in the upper joints and dorsal region of the human body. A detailed understanding of the undesirable effects of vibration on the human body is essential to achieve administrative and technical prevention. In modern times, vibration studies become more frequent, decisive for the many machines, vehicles and construction. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mechanical modeling of medical mesh implants at the mesoscale
Authors: Röhrnbauer Barbara , Kress Gerald , Mazza Edoardo 
Published: December 2012

AbstractThe present study is aimed at a physically based mechanical model for prosthetic meshes at the mesoscale. The geometry and the local kinematics of a representative unit cell are mapped in an abstracted, but still physically relevant description. Such a model allows to understand the interplay between local deformation patterns and the resulting global anisotropic and nonlinear force response. It is expected to provide design criteria for mesh implant optimization, not only accounting for the global mechanical behavior but also for local mesh‐tissue interactions. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Towards a Method for Parameter Estimation of Articular Cartilage and a Staggered Procedure for Synovial Fluid‐Cartilage Interaction
Authors: Mabuma Joffrey , Markert Bernd , Ehlers Wolfgang 
Published: December 2012

AbstractUp to now, the interaction mechanisms between cartilage and synovial fluid within diarthrodial joints are not fully understood. These joints are able to function effectively over the lifetime of an individual even under very high loads, which requires minimal wear of cartilage. In particular, the reason for the extremely low coefficients of friction has still to be explained.The goal of this contribution is to numerically investigate the interaction between articular cartilage and synovial fluid in diarthrodial joints. In this connection, we already developed an appropriate continuum model of the articulating tissue layers as highly anisotropic and heteregeneously charged biphasic solid‐fluid aggregates based on the Theory of Porous Media (TPM). The calibration of the previously elaborated model is the next concern. To this end, a sensitivity analysis is performed to identify the relevant constitutive parameters governing the cartilage response during indentation tests. The remaining parameters are then estimated numerically using a direct search algorithm. Next, a sequential solution algorithm has to be developed in order to solve the complex contact problem at the interface between synovial fluid and articular cartilage. Thereby, the fluid and cartilage domains are iteratively calculated until equilibrium is reached. For the moment, simulations are performed on a 3‐d hip‐joint geometry reconstructed from MRI data, which proceed from a continuum‐mechanical description of the synovial fluid gap. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New three‐dimensional finite elements with embedded strong discontinuities to model solids at failure
Authors: Zhang Xiaoxuan , Linder Christian 
Published: December 2012

AbstractThis work focuses on the development of new finite elements which can capture strong discontinuities in three‐dimensional failure problems. The displacement jumps in the solid are approximated by a linear interpolation obtained by enforcing a new class of enhanced separation modes to exactly be satisfied by the formulation. Efforts are also put towards the development of a proper crack propagation tracking algorithm needed for the complicated crack surfaces appearing in realistic 3D failure simulations, based on a combination of the global tracking algorithm and the marching cubes algorithm. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Monitoring fatigue cracks and stress intensity factors based on local strains
Authors: Boukellif Ramdane , Ricoeur Andreas 
Published: December 2012

AbstractA method for crack detection and stress intensity factor measurement in plate structures is presented by using strain gauges and applying the Body Force Method (BFM). The BFM is based on elastic solutions for concentrated loads and the principle of linear superposition allowing e.g. the calculation of the strain field in a cracked body. The inverse problem is solved applying the PSO (particle swarm optimization) and the unknown parameters are crack position, length and inclination as well as loading quantities. Experiments are carried out under cyclic loading using pre‐cracked plates made of aluminum alloy. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Damage processes coupled with phase separation in elastically stressed alloys
Authors: Heinemann Christian , Kraus Christiane 
Published: December 2012

AbstractIn micro‐electronic materials such as solder alloys, phase‐separation and coarsening as well as damage phenomena occur at the same time and influences each other. In this note, a unifying model which couples multi‐component Cahn‐Hilliard systems with elasticity and uni‐directional damage processes is presented. We outline the equations and their initial‐boundary conditions in a classical setting and cite some existence results for weak solutions recently proved in [8, 9]. The damage is assumed to be incomplete, i.e. the maximal damaged material parts still feature elastic properties. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Relaxed Incremental Variational Formulation for Damage in Fiber‐Reinforced Materials
Authors: Balzani Daniel , Ortiz Michael 
Published: December 2012

AbstractAn incremental variational formulation for damage at finite strains is proposed based on the classical continuum damage mechanics. Since loss of convexity is obtained at some critical deformations a relaxed incremental stress potential is constructed which convexifies the original non‐convex problem. The resulting model can be interpreted as the homogenization of a micro‐heterogeneous material bifurcated into a strongly and weakly damaged phase at the microscale. A one‐dimensional relaxed formulation is derived and based thereon, a model for fiber‐reinforced materials is given. Finally, some numerical examples illustrate the performance of the model. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crack growth in elastic materials with internal boundaries and interfaces
Authors: Judt Paul , Ricoeur Andreas 
Published: December 2012

AbstractThis work presents numerical methods used for predicting crack paths in technical structures based on the theory of linear elastic fracture mechanics. The FE‐method is used in combination with an efficient remeshing algorithm and a post processor to calculate crack tip loading. The interaction of cracks and internal boundaries and interfaces is investigated. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phase Field Modeling of Fracture in Plates and Shells
Authors: Ulmer Heike , Hofacker Martina , Miehe Christian 
Published: December 2012

AbstractThe numerical modeling of failure mechanisms in plates and shells due to fracture based on sharp crack discontinuities is extremely demanding and suffers in situations with complex crack topologies. This drawback can be overcome by a diffusive crack modeling, which is based on the introduction of a crack phase field. In this paper, we extend ideas recently outlined in [1, 2] towards the phase field modeling of fracture in dimension‐reduced continua with application to Kirchhoff plates and shells. The introduction of history fields, containing the maximum reference energy obtained in history, provides a very transparent representation of the coupled balance equations and allows the construction of an extremely robust operator split technique. The performance of the proposed models is demonstrated by means of representative numerical examples. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Phase Field Model for Ductile to Brittle Failure Mode Transition
Authors: Hofacker Martina , Miehe Christian 
Published: December 2012

AbstractThe computational modeling of failure mechanisms in solids due to fracture based on sharp crack discontinuities suffers in dynamic problems with complex crack topologies. This can be overcome by a diffusive crack modeling based on the introduction of a crack phase field. We outline a conceptual framework for phase field models of crack propagation in brittle elastic and ductile elastic‐plastic solids under dynamic loading and investigate the ductile to brittle failure mode transition observed in the experiment performed by Kalthoff and Winkeler [3]. We develop incremental variational principles and consider their numerical implementations by multi‐field finite element methods. To this end, we define energy storage and dissipation functions for the plastic flow including the fracture phase field. The introduction of local history fields that drive the evolution of the crack phase field inspires the construction of robust operator split schemes. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A comparative study of deformations of elastic‐viscoplastic plates using different structural hypotheses
Authors: Stoffel Marcus , Vu Thang Duy , Schmidt Rüdiger , Weichert Dieter 
Published: December 2012

AbstractIn the present study, circular metal plates are subjected to impulsive loadings leading to geometrically and physically non‐linear deformations. In the theoretical model, different structural hypotheses are implemented into a finite element code and the hypotheses leading to the most precise numerical predictions are studied. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Microstructural Model of a Closed‐Cell Foam on the Basis of Image Analysis
Authors: Fahlbusch Nina‐Carolin , Becker Wilfried 
Published: December 2012

AbstractThe focus of this work is the identification of a unit cell that is able to represent the microstructure of a closed‐cell solid foam to predict the effective behaviour of the foam numerically. For the investigation, a finite element model consisting of a repeating unit cell with periodical boundary conditions is implemented. A tetrakaidecahedral foam microstructure is considered as simplified cell geometry, and a strain‐energy based homogenisation concept is utilized. On the basis of image analysis imperfections are applied to the cell. The obtained model is used as a representative volume element (RVE) for further investigations of the postbuckling behaviour of the foams. Different analyses are performed and the results are compared to literature and experimental data. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simplified assessment of high‐speed train induced bridge vibrations considering shear effects
Authors: Salcher Patrick , Adam Christoph 
Published: December 2012

AbstractA novel response spectrum methodology for rapid assessment of the dynamic peak acceleration response of simple railway bridges subjected to high‐speed trains is presented. This methodology is based on non‐dimensional characteristic bridge and train parameters, and on the shear beam theory. The effect of shear deformations should be considered, if the considered bridge is a truss structure. Depending on the train load model, response spectra are derived for each modal coordinate separately as a function of a non‐dimensional speed parameter and the bridge length to wagon length ratio. An estimate of the peak response is found by statistical combination of the individual modal responses applying different rules. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Failure analysis of highly predeformed beams used as flexure hinges
Authors: Kern Dominik , Rösner Malte , Seemann Wolfgang 
Published: December 2012

AbstractThe trend to extend the working ranges of flexure hinges implies large deformations during operation. To conduct a failure analysis the total deformation is decomposed into desired deformation and deviations. In particular, a flexure hinge of leaf‐spring type is examined. It is modeled by the theory of elastica. The resulting boundary value problem is solved numerically for the static case by Ritz's method. It is discretized into trial functions and their free coefficients are determined from the minimum of potential energy by optimization methods. The crucial point is that the elastic energy stored in the beam is formulated intrinsically, while the potential of external conservative loads is formulated in a space‐fixed coordinate system. The well‐known special case of buckling of a straight cantilever beam is used for verification. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Elastic limit analysis of a thick‐walled cylindrical panel subject to radial heating
Authors: Arslan Eray , Mack Werner 
Published: December 2012

AbstractSubject of the investigation is a cylindrically curved thick‐walled shell guided at the ends which is heated at its outer surface. In particular, the thermal conditions at the elastic limit according to Tresca's yield criterion as well as the couples occuring in the elastic and elastic‐plastic state are studied. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Solid‐Shell Finite Elements for Tesselated Geometries
Authors: Wimmer Johannes , Reese Stefanie 
Published: December 2012

AbstractSandwich structures made of sheets of composite materials are in widespread use, particularly in the transportation industry. Finite Element simulation of the thin, tesselated structures with complex, three‐dimensional material behaviour is a challenging task for the underlying element technology. In particular, frequently used linear isoparametric approaches exhibit unphysical stiffening phenomena. Recent developments in solid‐shell finite element technology aim to overcome these undesirable effects. Here, they are applied to an example of a corrugated sandwich core under transversal compression. A study of convergence is conducted with respect to commercially available shell and solid finite elements, and their ability to reproduce the bending dominated deformation state. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Homogenization of thin structured sheet metals by using FEM
Authors: de Silva Tina , Kühhorn Arnold , Golze Mark 
Published: December 2012

AbstractThin structured sheet metals promise high potential concerning lightweight design in industrial applications regarding the classical mechanical engineering and vehicle construction as well as the aeronautics.Compared to flat, unstructured sheet metals the component stiffness and buckling behavior can significantly be improved by structuring especially in out of plane direction.To be able to calculate the elastic behavior of large structures from structured sheet metals a mechanical surrogate model is developed which describes effectively average material parameters based on processes of homogenization.For the surrogate properties symmetry and antisymmetry boundaries and periodic boundaries respectively are contemplated on elementary cells whose structural mechanical behavior is decisive.By using an energetic approach [3] the stiffnesses of large plate and shell structures can be determined by a cooperatively small amount of finite elements. By means of these material properties elastic behavior can easily be calculated. With it an efficient numerical design is guaranteed.This explained analysis can be applied to other periodically built up plate structures. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Elastic‐plastic states of two‐layer curved bar under pure bending
Authors: Sülü Ismail Y. , Arslan Eray 
Published: December 2012

AbstractAnalytical solution of an elastic‐partially plastic two‐layer curved bar subjected to couples at both ends is obtained. The solution is based on Tresca's yield criterion and its associated flow rule. Numerical results for real engineering materials in partially plastic stress state are presented in graphical form. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)