bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elastodynamic Contact Problems for Interface Cracks under Harmonic Loading
Authors: Mikucka Vita , Menshykov Oleksandr , Menshykova Maryna 
Published: December 2011

Abstract2‐D fracture dynamics' problems for elastic bimaterials with cracks located at the bonding interface under the oblique time harmonic wave are considered in the study. The system of boundary integral equations for displacements and tractions is derived from Somigliana identity taking the contact interaction of the opposite crack faces into account. For the numerical solution the collocation method with piecewise constant approximation is used. The numerical results are obtained for various values of the angle of the wave incidence and the wave frequency taking the friction effects into account. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermodynamically and variationally consistent cohesive zone models for large deformation
Authors: Mosler Joern , Scheider Ingo 
Published: December 2011

AbstractThe thermodynamical and variational consistency of cohesive zone models is analyzed in the present contribution. Based on a naive application of the classical Coleman & Noll procedure, it is shown that the second law of thermodynamics is not fulfilled in general. This can even be seen, in case of hyperelastic interfaces. For guaranteeing thermomechanical consistency, additional surface stresses acting at the interface have to be introduced. Based on such findings, a thermomechanically consistent model including dissipative effects is proposed. This model possesses a natural variational structure. More precisely, all state variables can naturally and jointly be computed by minimizing an incrementally defined potential. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fracture Mechanical Analysis of Cracks in Ice Shelves using the Finite Element Method and Configurational Forces
Authors: Plate Carolin , Müller Ralf , Gross Dietmar , Humbert Angelika 
Published: December 2011

AbstractIce shelves are important elements of the climate system and sensitive to climate changes. The disintegration of large Antarctic ice shelves is the focus of this fracture mechanical analysis. Ice is a complex material which, depending on the context, can be seen as a viscous fluid or as an elastic solid. A fracture event usually occurs on a rather short time scale, thus the elastic response is important and linear elastic fracture mechanics can be used. The investigation of the stress intensity factor as a measure of crack tip loading is based on a 2‐dimensional analysis of a single crack with a mode‐I type load and additional body loads. This investigation is performed using configurational forces. Depth dependent density and temperature profiles are considered. The relevant parameters are obtained by literature, remote sensing data analysis and modeling of the ice dynamics. The criticality of wet surface cracks is investigated. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crack plane identification in anisotropic linear elastic material using the reciprocity principle
Authors: Steinhorst Peter , Sändig Anna‐Margarete 
Published: December 2011

AbstractNondestructive test methods are important for examination of elastic devices regarding existence, position and size of cracks. In the case of hidden cracks (which do not touch the boundary), a simple visual control is not sufficient. The basic idea of this paper is to examine appropriate boundary measurements under certain loads. We focus on a method presented by ANDRIEUX, BEN ABDA and BUI [1] for isotropic linear elasticity, and generalize the crack plane detection to anisotropic linear elastic material. The main idea is the use of the reciprocity principle in order to connect data from the outer boundary with the unknown crack properties. Some 2D numerical examples demonstrate, that the method is working with simulated data. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Moving Kriging Interpolation‐based Meshfree Method for Dynamic Analysis of Structures
Authors: Bui Tinh Quoc , Zhang Chuanzeng 
Published: December 2011

AbstractA novel meshfree model based on the standard element‐free Galerkin method incorporated moving Kriging interpolation (MK) is developed for free and forced vibration analysis of 2D structures. Instead of employing moving least square approximation (MLS), shape functions here are constructed by the MK method. Due to the satisfaction of the Kronecker delta function, the essential boundary conditions are thus imposed directly as the finite element method and no special techniques are required. Elastodynamic equations are transformed into a standard weak formulation and then discretized into a meshfree time‐dependent equation solved by the standard Newmark time integration method. Some numerical examples of stuctural problems in 2D are attempted, and it is found that the method is adequately accurate and stable for dynamic problems. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sensitivity study of the contact situation between the brake pad and the disc
Authors: Dombek Dominika , Ostermeyer Georg‐Peter 
Published: December 2011

AbstractThe contact situation between the brake pad and the disc during the braking process is of particular importance concerning the squeal behavior of brake systems. After the braking process, the surface topography of brake pads can be measured using a confocal microscope. An algorithm to calculate the contact between two surfaces has been developed at the Institute of Dynamics and Vibrations. The algorithm calculates the deflection of asperities under a normal load regarding an elastic material behavior. A normal load is applied to a measured surface topography of the brake pad; the counter body (brake disc) is represented by a flat surface. The potential contact area, the locally distributed forces, deflections and normal stiffness of the pad are computed. Since there is an uncertainty in the relative position between the pad and the disc and hence the real contact situation during the braking process is not known, different contact situations must be considered during the simulations. Concerning various tilt angles of the pad that can arise during the vibrations of the brake system, a sensitivity study has been carried out. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
FE Analysis using Recurrent Neural Networks for Uncertain Stress‐Strain‐Time Dependencies
Authors: Freitag Steffen , Graf Wolfgang , Kaliske Michael 
Published: December 2011

AbstractA new soft computing approach is described, which can be applied for the identification of uncertain time‐dependent material behaviour. Artificial neural networks are utilized for model‐free material formulations. Uncertain stress‐strain‐time dependencies obtained from uncertain results of experimental investigations are described by recurrent neural networks for fuzzy data. An incremental finite element formulation is presented using neural networks instead of material models. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural contact problems for large deformations ‐ Comparison of steady and non steady normal field
Authors: Hammer Michael E. 
Published: December 2011

AbstractWe will present a comparison between two formulations of the normal vector field for contact algorithms based on the mortar method. First the non steady normal field is discussed. The non steadiness is a result of the C0 continuity of the boundary discretization. This is the common result if one discretize the domain with classical finite element methods. Second we will present results for a special normal field distribution. We average the nodal normal vector of two ascending edges and interpolate this nodal normal throughout the edges. We have implemented both methods and present comparisons based on numerical experiments. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Large deformation and stability of a shear‐deformable beam with a variable length under a uniformly distributed force
Authors: Humer Alexander 
Published: December 2011

AbstractA beam held by two spatially fixed supports, may slide relative to these as soon as external loads are imposed. In particular, the possibly large deformation of a shear‐deformable beam under a uniformly distributed, transverse force is investigated, which is clamped at its left side, while it may slide horizontally through another clamping device at its right side. Consequently, the material point of the beam that is currently located at the latter and the length of the portion of the reference configuration situated in between the two supports depend on the external forces and therefore are not known in advance. In order to obtain approximate solutions, a finite element scheme is utilized, in which a coordinate transformation is introduced, by which the difficulties of non‐material boundary conditions and the unknown length of the beam are circumvented elegantly. It turns out that no static equilibrium is found, if the external forces are increased beyond a critical value, since the beam would slide out infinitely in that case. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of a Compliant Mechanism for Positioning in the cm‐Range
Authors: Kern Dominik , Seemann Wolfgang 
Published: December 2011

AbstractThe kinematics and kinetics of a compliant mechanism are analyzed quasi‐statically. The mechanism consists of a parallelkinematic (Biglide type) with the particular feature, that its revolute joints are implemented by flexure hinges. In the considered example the flexure hinges are uniform beams similar to leaf springs. The preliminary considerations with a rigid body system and by linear theory of elasticity result in an initial geometry. In order to predict the large displacement behavior more precisely the theory of Elastica is used. An optimization method is applied to solve the mechanism's state of deformation. It was found that some aspects can be approximated by a pseudo rigid body system, while others, namely the rotation, cannot be rendered. The decreased stiffness in the highly deformed operating state appears as key problem. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simulation of the chipping behavior of coated abrasives by cooperating cellular automata
Authors: Kummer Bastian , Ostermeyer G.‐P. , Müller M. , Fricke A. , Hoffmeister H.‐W. 
Published: December 2011

AbstractDuring the production of high‐grade wooden components often the conditioning with coated abrasives composes the end of the process train. The chipping process and the resulting wood surface are depending of the scatter pattern parameters (particle size and distribution, …) and their time depending variations. Till now, no models exist concerning the interaction of the scatter pattern with the grinding process, the work piece surface and the clogging. The developed model is based on cooperating cellular automata. One is describing the sandpaper, the other one the work piece. These two automata interacts witch each other. Update rules are designed by physical laws and measurements. The paper shows surprising results with respect of surface structures which are the result of self‐organization effects in the boundary layer of wood and sandpaper. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fundamental solutions for a partially saturated poroelastic continuum
Authors: Li Peng , Schanz Martin 
Published: December 2011

AbstractThe Boundary Element Method is quite suitable for solving dynamic semi‐infinite or infinite linear problems. In order to establish the boundary integral equations, one crucial condition is the knowledge of corresponding fundamental solutions. For a partially saturated poroelastic continuum, the governing equations in Laplace domain are formulated based on the theory of mixtures, and the related fundamental solutions are derived by using Hörmanders method. The singular behavior of the fundamental solutions are investigated by a series expansion with respect to the variable r. Finally, some exemplary fundamental solutions are calculated to visualize the principal behavior as well, and comparisons with the related results of saturated poroelasticity are given. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Applications of Rosenbrock‐type methods to the p‐version of finite elements
Authors: Netz Torben , Hartmann Stefan , Hamkar Ahmad‐Wahadj 
Published: December 2011

AbstractIn quasistatic solid mechanics the spatial as well as the temporal domain need to be discetized. For the spatial discretization usually elements with linear shape functions are used even though it has been shown that generally the p‐version of the finite elemente method yields more effective discretizations, see e.g. [1], [2]. For the temporal discretization diagonal‐implicit, see e.g. [4], and especially linear‐implicit Runge‐Kutta schemes, see e.g. [5], [6], have for smooth problems proven to be superior to the frequently applied Backward‐Euler scheme (BE). Thus an approach combining the p‐version of the finite element method with linear‐implicit Runge‐Kutta schemes, so‐called Rosenbrock‐type methods, is presented. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mechatronic system with shunted piezoelectric damper modelled with structural damping
Authors: Buchacz Andrzej , Płaczek Marek 
Published: December 2011

AbstractPaper presents analysis of an one‐dimension flexural vibrating mechatronic system. The considered system is a cantilever beam with a piezoelectric transducer bonded to the beam's surface. An external electric circuit is adjoined to the transducer's clamps in order to damp vibrations. System was analyzed on the basis of an approximate Galerkin method. Verification and assumptions of the approximate method were described in the previous papers where analysis of the mechatronic system with piezoelectric shunt damper was presented. Structural damping of all system's components was being taken into consideration. Rheological properties were introduced using Kelvin‐Voigt model of materials. Influences of component's structural damping coefficients values on the system's dynamic flexibility were defined. Obtained results were presented on 3D graphs as dynamic flexibility dependence on the structural damping coefficient and frequency of an external force that was applied to the system. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inelastic behavior of the single domain of metal‐ceramic composites with lamellar microstructure
Authors: Sinchuk Yuriy , Piat Romana , Roy Siddhartha , Gibmeier Jens , Wanner Alexander 
Published: December 2011

AbstractMetal‐ceramic composites are widely applied in the different brunches of industry. The composites are produced by squeeze‐casting of the ceramic preform by molten aluminum alloy. The lamellar microstructure is obtained during freezing of ceramic suspension. The internal structure of the domains can be controlled via freeze‐casting parameters. The material has high anisotropy level and its effective properties depend on lamella orientation. The aim of this study is numerical simulation of the inelastic behavior of the material and its verification by experiment. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Weighted Least‐Squares Mixed Finite Element Formulation for Quasi‐Incompressible Elastodynamics
Authors: Steeger Karl , Schwarz Alexander , Schröder Jörg 
Published: December 2011

AbstractThe purpose of this work is the application of the least‐squares finite element method to an elastodynamic, quasi‐incompressible problem under small strain assumptions. Therefore a mixed finite element based on a weighted least‐squares formulation is developed. The L2‐norm minimization of the time‐discretized residuals of the given first‐order system of partial differential equations leads to a functional depending on displacements and stresses. In the numerical example the proposed mixed element is compared to an alternative approach, which is based on a least‐squares mixed finite element with improved momentum balance, see [1]. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Verification of an optical metrology system (ARAMIS) by comparing experimental data with FE calculations and continuum approaches
Authors: Stier Bertram , Reese Stefanie 
Published: December 2011

AbstractOptical 3D field measuring systems, based on DIC (Digital Image Correlation) deliver kinematic quantities. They are appropriate devices helping to understand the material behavior especially at high strains. One problem of these systems is the missing information about material points located behind the observed surface of the specimen, which is needed to assign the full deformation gradient. Different ways of dealing with raw point coordinate data that is confidently given by the metrology system lead to different kinematic results. To ensure the correctness of strain‐like results determined by the system, they are compared to analytical and finite element calculations. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Parameter identification for nonlinear dynamical systems using Multi Harmonic Balance techniques
Authors: Süß Dominik , Willner Kai 
Published: December 2011

AbstractAn usual approach to investigate nonlinear systems in the frequency domain is the application of the Harmonic Balance Method (HBM), assuming that a harmonic excitation of the system leads to a harmonic response. However, for systems where the steady state response is not just harmonic but periodic or for systems which are excited periodically, this assumption does not longer lead to satisfying results. Therefore, the Multi Harmonic Balance Method (MHBM) is utilized. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An error indicator for parameter identification with stabilized mixed tetrahedrals
Authors: Widany Kai‐Uwe , Mahnken Rolf 
Published: December 2011

AbstractThe identification of parameters in constitutive laws considering inhomogeneous states of stress and strain is realized by iteratively minimizing a least squares functional. In each iterative step of this optimization problem a finite element analysis is carried out which results in a significant higher numerical cost than a single finite element analysis. Consequently, an efficient discretization is required to keep the numerical cost low. To address this problem an adaptive mesh refinement is considered which is based on a posteriori error indicators [1] leading to refinements appropriate to the parameter identification problem. The goal is to apply the error indicators to the finite element method for tetrahedral elements of low order which are preferable for adaptive mesh refinements and in addition reduce computational effort. Additional stabilization terms in the element formulation [4, 6] reduce volume locking effects making the elements suitable for (nearly) incompressible material behavior. Numerical examples illustrate the progress on this work. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On stability and self‐excited vibrations in fluid‐structure‐interaction
Authors: Bach Karolina , Hetzler Hartmut , Seemann Wolfgang 
Published: December 2011

AbstractIn flexible channels conveying fluid the steady state may loose stability by divergence or flutter. The aim of this contribution is to investigate the basic excitation mechanisms of flow‐induced vibrations and to evaluate the influence of various parameters on the stability behaviour of the coupled problem. Therefore, a simple, yet general model is proposed. The fluid is assumed to be inviscid and irrotational and both incompressible and compressible flow is considered. It is guided by a planar, rectangular channel with a rigid wall and a thin, flexible wall. The latter is modelled as a one‐parametric continuum on an elastic foundation, which exhibits bending and extensional stiffness. By examining the energy balance over one oscillation circle it is possible to reveal the mechanisms of energy transfer between the coupled components of the system. Based on this analysis a physical explanation of the arising instabilities is possible. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simulation of friction phenomena between randomly rough elastic surfaces
Authors: Gaus Nicole , Proppe Carsten 
Published: December 2011

AbstractFriction induced vibrations are a widely studied field in which the friction coefficient is one of the most important parameters. Measurements show that the friction coefficient underlies stochastic fluctuations. To gain more knowledge about the friction coefficient a finite element study is carried out in order to simulate the friction forces. The Bowden‐Tabor model is implemented which calculates the friction force as the force which is needed to shear apart contact areas hold together by welding or adhesion. The dependency of the friction value on sliding velocity and normal pressure can be determined with this model. Different realization are studied and the stochastic properties of the friction value such as mean value, standard deviation, amplitude spectrum and correlation coefficient can be calculated depending on the roughness of the surface. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonlinear vibrations of elastic beams with external general visco‐elastic devices
Authors: Heuer Rudolf , Pirrotta Antonina 
Published: December 2011

AbstractVibration damping for slender beams is achieved by applying devices at external points. The latter consist of general single visco‐elastic springpot elements. An approximate nonlinear boundary value problem is found in frequency domain that holds for moderately large vibrations or for linear beams with external nonlinear devices, both in the vicinity of primary resonances. The interaction force of a so‐called springpot element is expressed as a sum of two separate forces: the first develops due to the external loading function at the device location, and the second contribution arises due to an imposed time‐harmonic support excitation with no other external forces acting on the structure. Finally the nonlinear frequency response function follows from a (nonlinear) algebraic equation where the influence of the springpot element appears as isolated parameter. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling aspects and numerical analysis of offshore systems
Authors: Jesussek Mathias , Ellermann Katrin 
Published: December 2011

AbstractThere is a strong effort to improve the efficiency of renewable energy systems in order to reduce the CO2 emissions. This paper addresses an approach to increase the efficiency of an ocean wave energy plant with a model based predictive controller. For this controller it is necessary to have a prediction of the ocean waves and a model of the whole system. The future development of the ocean waves is predicted by an AR‐model. A system identification yields the model of the energy plant. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigations on the numerical solution of the Fokker‐Planck equation with discontinuous Galerkin Methods
Authors: Loerke Friederike , Nackenhorst Udo 
Published: December 2011

AbstractNonlinear dynamic systems under stochastic excitation possess Markov characteristics. Thus, their stochastic equation of motion can be transformed into the Fokker‐Planck equation which describes the evolution of the probability density. A discontinuous Galerkin (DG) method is applied to solve the Fokker‐Planck equation. This method provides numerical stability as well as accuracy and is able to treat discontinuities of the solution. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)