bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Porous Media Model for the Description of Adaptive Bone Remodelling
Authors: Krause Robert , Markert Bernd , Ehlers Wolfgang 
Published: November 2010

AbstractBones are strong and lightweight structures, which mainly consist of extracellular bone matrix. The bone remodelling is a process of resorption followed by replacement of the bone matrix with small changes in shape, which allow the bones to adapt according to the local loading situation.In the context of the Theory of Porous Media (TPM), a consistent model of bone tissue is introduced, which is able to describe the local accretion and reduction of the extracellular bone matrix. To this end, the bone is treated as an aggregate of two immiscible constituents. In this biphasic macroscopic model, the aggregate consists of the extracellular bone matrix and cells summarised to a solid phase and an interstitial fluid phase comprising nutrients, metabolites and bone precursors. The addition and removal of bone matrix is described by a mass exchange between the constituents, which depends upon the local strain of the material. Additionally, the growth energy is introduced as a non‐mechanical quantity, which measures the average amount of chemical energy available for cell metabolism [1, 2], and thus, controls the growth process. The presented numerical example illustrates the fundamental effects of bone remodelling under varying boundary conditions. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A bioactive interface approach for the simulation of mechanically stimulated osseointegration of hip joint endoprostheses
Authors: Lutz André , Nackenhorst Udo 
Published: November 2010

AbstractIn this contribution, an approach on the mechanically stimulated osseointegration of hip joint endoprostheses considering load cases of daily movements is presented. The mechanical behavior of the bone‐implant interface is modeled with a material model adopted from computational plasticity. Under consideration of a detailed analysis of the interface conditions, limiting factors for the osseointegration process are identified and the bone ingrowth prediction is performed. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mechanical Modeling of Particle‐Droplet Interaction Motivated by the Study of Self‐Cleaning Mechanisms
Authors: Osman Muhammad , Sauer Roger A. 
Published: November 2010

AbstractMotivated by the study of self‐cleaning surfaces, the interaction between a spherical solid particle and a water droplet is studied on the microsale level, in terms of the balance forces and the surface properties. To define the forces acting on the solid‐liquid interface, the meniscus depression is computed from the Young‐Laplace equation, using a non‐linear finite element formulation. The equilibrium force is derived in terms of the contact angle, particle size, and the penetration. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of Medial and Adventitial Layer on Arterial Adaptation
Authors: Schmid Holger , Poshtan Emad A. , vanHaag Jens , Grytsan Andrey , Itskov Mikhail 
Published: November 2010

AbstractMaterial properties in general and layer‐specific stiffness in particular are critical factors to predict the initiation and growth of aneurysms. Previous experimental studies show vastly differing material stiffness and metabolic activity in the media and the adventitia. In this paper a phenomenological model using FEM is applied in order to predict the adaptive response of the arterial wall in different mechanical and metabolic cases. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Improving the inverse kinematics reconstruction of human movement from motion capture data
Authors: Simonidis Christian , Seemann Wolfgang 
Published: November 2010

AbstractMarker based motion capture methods are well known techniques for the acquisition of human motion. For the kinematic and dynamic analysis the recorded data is usually used to drive a rigid body model of the human body. Skin artifacts, which are caused by skin deformation and displacement of markers with respect to the underlying bone, are regarded as the most critical source of error in the inverse kinematics reconstruction of human movement. State‐of‐the‐art algorithms use optimization and multibody models with joint constraints in order to overcome these effects. This work presents an optimization based inverse kinematics approach, which is able to adapt the model kinematics subject‐specifically and to compute the time trajectories of kinematic variables from marker data including velocity and acceleration. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Biomechanical modelling of cellular articular cartilage replacement tissues
Authors: Stoffel Marcus , Yi Jeong Hun , Weichert Dieter , Gavenis Karsten , Müller‐Rath Ralf 
Published: November 2010

AbstractThe aim of the present study is to investigate the strength and damping properties of cellular articular cartilage replacement material. For this purpose, a viscoelastic‐diffusion model for the acellular water‐saturated condensed collagen gel type I is proposed and validated experimentally. Moreover, a remodelling law for the cell seeded collagen gel is introduced. For an experimental study of the interaction between fibre growth and mechanical stimulation, bioreactors are developed and histological investigations are carried out. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental and numerical investigations in skeletal muscle modelling
Authors: Sturmat Maike , Kober Cornelia , Böl Markus 
Published: November 2010

AbstractIn the present paper, a method to compare displacement results of a muscle contraction simulation with results of optical experiments is proposed. A human skeletal muscle has been reconstructed to a volume element out of real two‐dimensional MRI data. The surrounding tissue has also been taken into account in order to describe the interaction with other components in a realistic way. These regions of the interface have been supported by several spring stiffness. The numerical model has been fitted by this stiffness on one significant node. The results shown satisfied agreement with the optical experiments. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Microscopic model for a cell‐seeded material
Authors: Yi Jeong Hun , Stoffel Marcus , Weichert Dieter , Gavenis Karsten , Müller‐Rath Ralf 
Published: November 2010

AbstractThe aim of the present paper is to account for the growth of fiber which is observed in a cell‐seeded material stimulated in a bioreactor. For this purpose, the change of mass is considered in the balance laws, and the deformation energy is assumed to be a function of varying mass and the Helmholtz free‐energy. Fiber growth at the microscopic level causes a macroscopic change of the material's mechanical properties. The study is a first approach towards a micromechanical model accounting for remodelling in cartilage replacement materials. In so doing, constitutive equations for renewable soft tissues are proposed. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of damage and fracture mechanisms on the micro‐scale
Authors: Albrecht Daniel , Brünig Michael 
Published: November 2010

AbstractThe paper deals with generalized damage and failure criteria taking into account different mechanisms on the micro‐scale. Some micro‐mechanical numerical results are discussed and compared with the macroscopic analysis based on the continuum damage model. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of the material gradation on the SIFs of a crack in a 2‐D FGM plate under thermal shock
Authors: Ekhlakov Alexander , Khay Oksana , Zhang Chuanzeng 
Published: November 2010

AbstractCrack analysis of linear coupled thermoelasticity in two‐dimensional, isotropic, non‐homogeneous and linear elastic functionally graded materials subjected to thermal shock is performed by using a boundary‐domain element method. The material parameters are assumed to be continuous functions of the spatial coordinates. Fundamental solutions of linear coupled thermoelasticity for the corresponding isotropic, homogeneous and linear elastic solids in Laplace‐transformed domain are applied in the boundary‐domain integral formulation. A collocation method is implemented for the numerical solution. Numerical examples for an exponential gradation of the material parameters are presented and discussed. The influences of the material gradation on the stress intensity factors are investigated. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Thermodynamically­Consistent Phase Field Model for Electromechanical Diffusive Crack Propagation
Authors: Hofacker Martina , Miehe Christian , Welschinger Fabian 
Published: November 2010

AbstractThe computational modeling of failure mechanisms in solids due to fracture based on sharp crack discontinuities suffers in situations with complex crack topologies and for crack initiation in bodies free of defects. This drawback can be overcome by a diffusive crack modeling based on the introduction of a crack phase field. In [1,2], we developed a phase‐field‐model of brittle fracture, which is conceptually in line with gradient‐type continuum damage models. Its global response is governed by an incremental variational principle, whose Euler equations describe the balance of linear momentum and the evolution of the crack topology. In this paper, the proposed model is extended to a thermodynamically consistent four‐field setting of coupled electromechanical fracture, based on a degrading mixed energy‐enthalpy functional and an over‐force‐type dissipation functional. These functionals are expressed in terms of the displacement, the electric potential, the fracture phase and its dual driving‐force fields. Evaluation of the necessary condition yields, in addition to the above mentioned Euler equations, the Gauss‐law of electrostatics. The capability of the proposed framewok for the description of electromechanically coupled crack propagation is demonstrated by means of a representative numerical example. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Damage and Failure of Metal/Fibre‐Reinforced Polymer Tensile Specimens with Inelastic Interface
Authors: Konchakova Natalia , Mueller Ralf , Barth Franz‐Josef 
Published: November 2010

AbstractHybrid specimens of metal and fibre‐reinforced polymer are applied in automotive and aerospace industry. The simulation and analysis of damage of such engineering structures is the focus of this research. The investigation includes a computation of the extension of single lap tensile specimen, produced by ultrasonic metal welding. The specimen is manufactured from CF‐PA66 ‐ fibre‐reinforced polymer and AlMg3 (AA5754), which is used as a metallic joining partner. The aluminium substrate is treated as an elastoplastic material. The polymer composite generally shows an orthotropic elastic behaviour. The interface material has been numerically modeled as an elastoplastic material with linear hardening, coupled with Lemaitre‐type damage. The finite element method is used for the investigation of so‐called interface elements. The geometry of the interface is a consequence of the welding sonotrode geometry. The behaviour of specimens with square and ring interface geometry are analysed. The influence of the interface geometry on the mechanical properties of the joint is shown. The increase of the damage parameter and the development of failure are described for both cases. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Implementation of a cohesive zone model for the investigation of the dynamic behavior of a rotating shaft with a transverse crack
Authors: Liong Rugerri Toni , Proppe Carsten 
Published: November 2010

AbstractThe influence of a transverse crack on the vibration of a rotating shaft has been at the focus of attention of many researchers. The knowledge of the dynamic behavior of cracked shaft has helped in predicting the presence of a crack in a rotor. Here, the changing stiffness of the cracked shaft is investigated based on a cohesive zone model. This model is developed for mode‐I plane strain and accounts for triaxiality of the stress state explicitly by using basic elastic‐plastic constitutive relations. Then, the proposed numerical solution is compared to the switching crack model, which is based on linear elastic fracture mechanics. The cohesive zone model is implemented in finite element techniques to predict and to analyse the dynamic behavior of cracked rotor system. Timoshenko beam theory is used to model the discrete shaft under the effect of gravity, unbalance force and gyroscopic effect. The analysis includes the cohesive function for describing the breathing crack and the reduction of the second moment of area of the element at the location of the crack. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling of material failure by combining the advantages of embedded strong discontinuity approaches and classical interface elements
Authors: Radulovic Radan , Mosler Jörn 
Published: November 2010

AbstractA finite element formulation within the framework of the Strong Discontinuity Approach suitable for the simulation of crack growth is presented. The formulation allows for intersecting discontinuities and similarly to classical interface elements, the cracks are introduced parallel to the element facets. However and in contrast to interface elements, the discontinuities are directly embedded in finite elements, based on the Enhanced Assumed Strain concept. It is shown that a realistic prediction of the mechanical response requires the consideration of more than one crack within each finite element. The proposed formulation is suitable to overcome locking effects and it automatically fulfills crack path continuity. The approach is strictly local yielding an efficient numerical formulation. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the search of supersingularities, more severe than a common crack singularity
Authors: Sator Christian , Becker Wilfried 
Published: November 2010

AbstractStress singularities at two‐dimensional multi‐material‐junctions, consisting of dissimilar, homogeneous, isotropic and linear‐elastic wedges under a plane strain state are considered. The stresses formed at the vertex of this multi‐material composite situation are analyzed by complex variable method, based on a choice of the Kolosov‐potentials which are applicable in the vicinity of the vertex. The characteristic equation for the order of the stress singularities is available in a closed‐form analytical manner and investigated numerically. By varying parameters, like the stiffness ratio of one material with respect to the remaining stiffnesses or the angle between the involved sectors of the junction, useful information about the variation of the order of the stress singularities is provided. A particular outcome of the performed investigations is that there are many situations where supersingularities occur, i.e. singularities more severe than those due to a crack inside a homogeneous material. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Application of the Arlequin method in the virtual engineering design process
Authors: Barthel Corinna , Gabbert Ulrich 
Published: November 2010

AbstractThe creation of a holistic model which is able to represent the global dynamic behavior as well as local effects in certain regions leads to finite element models consisting of domains with different local meshes and a combination of different model dimensions. The different model domains have to be coupled such causing in an additional coupling error. The Arlequin method seems to be a flexible tool which has some advantages in comparison to alternative methods. In this paper the application of the Arlequin method on the coupling of a 3D continua model and a beam model is studied. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the theory of orthotropic porous elastic rods
Authors: Bîrsan Mircea , Altenbach Holm 
Published: November 2010

AbstractWe employ the theory of elastic materials with voids to describe the mechanical behavior of porous rods. In this purpose, we consider the direct approach to the theory of rods, in which the thin body is modeled as a deformable curve with a triad of rigidly rotating orthonormal vectors attached to every material point. For orthotropic and homogeneous rods, we determine the constitutive coefficients in terms of the three‐dimensional elasticity constants by solving several problems in the two different approaches (directed curves and three‐dimensional rods). (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Static and dynamic analysis of cracked or weakened structures
Authors: Carl Oliver , Zhang Chuanzeng 
Published: November 2010

AbstractStiffness modifications in engineering structures, for example due to damage and cracking, will inevitably also lead to changes in deformations, internal forces, natural frequencies and mode shapes of the structures. In this paper, an efficient and simple method for sensitivity analysis of cracked or weakened structures under time‐harmonic loading is presented. The method is based on a comparison between the strain energy and the kinetic energy of an uncracked structure and that of a cracked structure in conjunction with the application of exact or approximate Green's functions as described in [3] for the static case. The present analysis enables the prediction of any changes in the displacements and stresses and has a lower computational effort as compared to available classical methods, because only the damaged region has to be re‐considered in the method. Green's functions are taken as a basis of the approach, which have the ability to weight the influence of the stiffness modifications in a region of a structure and show how sensitive other regions respond to the stiffness modifications.Based on linear elastic fracture mechanics, cracked or damaged regions are approximated by spring models in the analytical solution of some simple beam problems, while cracked finite elements are used for complicated cases where analytical solutions cannot be obtained. Sensitivity analysis with Green's functions (SAGF) approach is applied to static and dynamic analysis of cracked and weakened structures, which consist of homogeneous materials or fiber reinforced composites like reinforced concretes. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structure preserving integrators for non‐linear structural dynamics
Authors: Franke Marlon , Betsch Peter , Hesch Christian 
Published: November 2010

AbstractA well known and major drawback of standard time integration schemes in the field of non‐linear elastodynamics is their unstable behavior in the case of stiff material behaviour. Even second order accurate implicit time integration schemes are unable to resolve the problem under consideration effectively. To remedy this drawback, structure preserving integrators have been developed. Therefore, the goal of this paper is to compare recently developed integrators. In particular, an energy and momentum conserving scheme, based on a publication by Betsch & Steinmann [1], as well as a symplectic variational integrator, proposed by Lew et al. [4] and Wendlandt & Marsden [3], based on a mid‐point evaluation of the discrete Lagrangian, are presented. Two representative numerical examples will outline the characteristics of the different approaches. In particular, a stiff non‐linear spring pendulum and a finite element model of non‐linear structural dynamics are considered. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Prediction of Time‐Dependent Structural Responses with Recurrent Neural Networks
Authors: Freitag Steffen , Graf Wolfgang , Kaliske Michael 
Published: November 2010

AbstractA concept for the mapping of fuzzy structural action processes onto fuzzy structural response processes is presented. Recurrent neural networks for fuzzy data are developed for this mapping. The presented method can be applied to the model‐free numerical prediction of time‐dependent structural responses. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Verified Monotonicity‐Based Solution of a Simple Finite Element Model with Uncertain Node Locations
Authors: Smith Andrew P. , Garloff Jürgen , Werkle Horst 
Published: November 2010

AbstractA tight verified solution enclosure is obtained for the node displacements of a simple truss model, whose parameters, including the node locations, are uncertain. The solution is based on a monotonicity analysis of these interval parameters. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On Inverse Form Finding For Anisotropic Materials
Authors: Germain Sandrine , Scherer Michael , Steinmann Paul 
Published: November 2010

AbstractThe main goal of this paper is to extend the work of Govindjee and Mihalic (1996) to anisotropic hyperelasticity that is formulated in the logarithmic strain space involving a spectral decomposition of the right Cauchy‐Green tensor. Beside the theoretical aspects, we present a numerical example. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mortar‐Based Contact Formulation for Large Deformations
Authors: Hammer Michael E. 
Published: November 2010

AbstractThe discontinuities due to the discretization lead to some challenges. First, the normal direction of the contact surface is not steady because the discrete surface is only C0 continuous. One might smooth the normal vector field. Second, the question of contact enforcement has to be cleared. Contact forces can be modeled with either a Lagrange multiplier method or a penalty formulation to prevent penetration. Third, there must be developed a integration scheme which is able to handle the non‐steady boundary. Last, there is a strong discontinuity in measuring the penetration, where different criteria for enabling or disabling contact can be found (active set strategy). In this work, different approaches to solve this tasks are presented and brought into context. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Load and frequency interaction in dynamic buckling of soft‐core sandwich plates and shells
Authors: Hohe Jörg 
Published: November 2010

AbstractThe present study is concerned with an analysis of load‐frequency interaction effects in the dynamic buckling response of soft‐core sandwich plates and shells. Based on a higher‐order geometrically non‐linear sandwich shell theory in conjunction with an extended Galerkin procedure, a mathematical model together with analytical solution for simply supported sandwich plates and shells with with rectangular projection is obtained. By linearization of the non‐linear solution with respect to the oscillating parts, the interaction of the natural frequencies with static preloads can be analyzed. The results reveal that the transverse compressibility of soft sandwich cores might have distinct effects on the natural frequencies. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Buckling Analysis of Carbon Nanotubes
Authors: Hollerer Stefan 
Published: November 2010

AbstractIn this work, an atomistic‐continuum model is applied to single‐walled carbon nanotubes. The constitutive behaviour is described by the interatomic Tersoff‐Brenner potential. The coupling between atomistic deformation and the deformation of the continuum is done by an expanded Cauchy‐Born rule. With the help of this model, the buckling behaviour of carbon nanotubes under different loading conditions is studied. Numerical simulation results are given for two different types of loading (axial compression, torsion). (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)