bluuebunny/crossref_metadata_2025_split huggingface dataset:
Implementation of the Nitsche approach for various contact kinematics
Authors: Izi Ridvan , Konyukhov Alexander , Schweizerhof Karl 
Published: November 2010

AbstractNumerical approaches are in case of contact problems mainly dealing with additional terms enforcing constraints. Within the Nitsche approach the inclusion of constraints for the non‐penetration and equilibrium of stresses of the contacting bodies is carried out in a fully variational sense. Taking into account a specific choice and the physical meaning of the encountered Lagrange multipliers two different schemes for the Nitsche formulation are obtained. Both types of the Nitsche approach are implemented in a nonlinear element and verification with numerical examples is done. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vibrations of thin tolerance‐periodic plates
Authors: Wirowski Artur , Jędrysiak Jarosław , Kaźmierczak Magda 
Published: November 2010

AbstractIn this contribution, linear‐elastic thin plates with a tolerance‐periodic structure in planes parallel to the plate midplane are considered. It is assumed that their averaged (macroscopic) properties are described by continuous, slowly‐varying functions. Hence, plates of this kind can be treated as plates with a functionally graded structure. Here, free vibrations frequencies of a plate band are calculated within the proposed averaged model using the finite differences method. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Necessary and Sufficient Conditions for Zero‐stiffness Postbuckling
Authors: Jia Xin , Höfinger Gerhard , Mang Herbert A. 
Published: November 2010

AbstractIn the course of sensitivity analysis of the initial postbuckling behavior of elastic structures, a special case may occur which is referred to as zero‐stiffness postbuckling. The purpose of this paper is to present sufficient and necessary conditions for this special case which is associated with a favorable form of transition from imperfection sensitivity to imperfection insensitivity in the course of sensitivity analysis of the initial postbuckling path. Koiter's initial postbuckling analysis is chosen as the vehicle for quantification of the initial postbuckling behavior. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Contact simulation for the calculation of the kinematic excitation of vibrations from surface roughness of wheel and rail
Authors: Klotz Christian , Beitelschmidt Michael , Quarz Volker 
Published: November 2010

AbstractA simulation method has been developed to predict the sound emission of the railway wheelsets due to the excitation of wheelset vibrations by surface roughness of wheel and rail. This model treats the contact in a linearized manner and is therefore not capable of modelling the local effects of the roughness in the wheel‐rail contact zone. These effects are very important since the contact acts as a low pass filter which is calculated within a contact simulation. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Contact interaction inside knot connections of cables
Authors: Konyukhov Alexander , Schweizerhof Karl 
Published: November 2010

AbstractKnots as a method for the fastening of ropes and other linear materials are widely appearing in practical applications ­ in sailing, in surgery, in textile and rope structures etc. The mechanics of knots, however, appears to be not sufficiently covered neither by analytical methods, nor by computational methods. From a computational mechanics point of view a knot is a perfect example requiring both a robust smooth cable element and a robust curve‐to‐curve contact algorithm. The current contribution is aimed on the development this combination ­ the isogeometric approach for curvilinear beams and the robust curve‐to‐curve contact algorithm for curvilinear cables. The developed model is applied studying the mechanics of various knots. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Higher‐Order Composite Beam Theory for Closed‐Form Analysis of Beams with Box and I Cross‐Section
Authors: Kroker Andreas M. , Becker Wilfried 
Published: November 2010

AbstractFor many cases of beam structures such as composite beams with box or I cross‐sections, shear forces can not be neglected and it is necessary to take shear deformation into account. Therefore, a higher‐order theory for composite beams is developed. The cross‐section of the beams can be divided into webs and flanges, both are assumed to have different symmetric layups with balanced angles. The axial displacement representation is chosen to be of second‐order for the flanges and of third‐order for the webs. There is no transverse contraction allowed. All parts of a cross‐section are assumed to have the same deflection in vertical direction. The geometric coupling of the flanges and webs is ensured by corresponding constraints. Based on the introduced kinematic representation, the principle of minimum potential energy is used to derive the respective differential equations. These governing equations are solved in a completely closed‐form analytical manner. This way, a closed‐form description of the whole beam behavior is achieved. In particular, all resultant local in‐plane stresses can be obtained directly. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Design of continuous strain‐type sensors for systems of structural mechanics
Authors: Krommer Michael , Vetyukov Yury , Zellhofer Markus 
Published: November 2010

AbstractIn this paper, we present a general approach for designing continuous strain‐type sensors to measure specific kinematical entities in systems of structural mechanics. We first discuss the case of three‐dimensional bodies in the geometrically linear regime, for which the solution of the sensor design problem is found from a problem‐oriented application of a work‐based integral formulation to an auxiliary problem of statics; yet, the resulting sensor works for static and dynamic problems. The deduction of solutions for the sensor design problem on a structural mechanics level is straightforward, because the three‐dimensional solution is work‐based. Hence, for any theory of structural mechanics, for which a corresponding work‐based integral formulation exists, we can easily find a solution of the sensor design problem. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Artificial neural network based inverse reliability analysis
Authors: Lehký David , Novák Drahomír 
Published: November 2010

AbstractAn inverse reliability analysis is the problem to find design parameters corresponding to specified reliability levels expressed by reliability index or by theoretical failure probability. Design parameters can be deterministic or they can be associated to random variables described by statistical moments. The aim is to solve generally not only the single design parameter case but also the multiple parameter problems with given multiple reliability constraints. A new general approach of inverse reliability analysis is proposed. The inverse analysis is based on the coupling of a stochastic simulation of Monte Carlo type and an artificial neural network. A novelty of the approach is the utilization of the efficient small‐sample simulation method Latin Hypercube Sampling used for the stochastic preparation of the training set. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Parametric vibration of TMD installed in tall building during seismic excitation
Authors: Majcher Krzysztof , Wójcicki Zbigniew 
Published: November 2010

AbstractIn this paper shaking‐table tests of a model‐scale building with TMD (tuned mass damper) are conducted. The main aim of the research is to show the influence of kinematical excitation on the dynamic response of the model of tall building with pendulum TMD. The special attention is focused on the functioning of pendulum, which is simultaneously excited by the vertical component of ground motion. There are two kinds of analysis carried out — numerical and experimental. The numerical analysis of the problem is performed with using COSMOS/M system (a FEM numerical model is defined), while experimental analysis is carried out on a physical model‐scale building with TMD. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Highly Efficient Implementation of ANS/ EAS ‘Solid‐Shell’ Finite Elements for Explicit Time Integration
Authors: Mattern Steffen , Schweizerhof Karl 
Published: November 2010

AbstractIn an explicit time integration algorithm, the most time‐consuming part of an analysis is the computation of the internal nodal force vector. An implementation concept for element routines for volumetric shell ­ so‐called Solid‐Shell ‐ elements based on the application of the symbolic programming tool ACEGEN, a plug‐in for the computer algebra software MATHEMATICA is presented. Symbolic implementation means that vector and matrix operations and differentiations can be performed symbolically in order to generate program code, which supports the implementation, reduces programming effort and helps to avoid programming errors almost completely. The program code is generated in FORTRAN and simultaneously optimized automatically, which leads to very efficient routines compared to manually implemented code. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Eine analytische Lösung für die großen Deformationen bei den 4 Euler Knickfällen und ihre Anwendung auf Probleme der Mikroelektronik
Authors: Müller W. H. , Hauck T. 
Published: November 2010

AbstractDie höhere IO‐Pin Anzahl bei geringer werdendem Abstand und bei gleichzeitiger Vergrösserung von Wafern erfordert neue Testverfahren zur elektrischen Funktionalität. Die sog. Vertical‐Buckling Probe‐Nadeltechnik scheint ein gutes Konzept bei der experimentellen Erfassung des Vorliegens elektrischen Kontaktes zu sein: Die bei der Kontaktierung mit dem Pad gegebene Elastizität der Nadel führt zum Eulerknicken dergestalt, dass ein mehr oder weniger konstanter Kontaktdruck während des relativ langen Wegvorschubes gegeben ist. Dadurch erzielt man bei der Produktionstestphase ein hohes Toleranzniveau, um den wechselnden Planaritätsbedingungen des Wafers zu begegnen. Zur Dimensionierung einer Buckling‐Needle‐Probe ist es günstig, über geschlossene Lösungen zu verfügen, welche die geometrisch nichtlineare Deformation in Verbindung mit einer über der ersten kritischen Knicklast liegenden Kraft setzen. Hierzu werden im Aufsatz analytische Lösungen der Differentialgleichung für die Elastica bei den Eulerfällen vorgestellt, diskutiert, angewendet und auch mit FE‐Berechnungen verglichen. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Poroelastodynamic Plate Formulation of Extendable Order
Authors: Nagler Loris , Schanz Martin 
Published: November 2010

AbstractIn order to model the sound insulation properties of porous plate‐like structures, an adequate poroelastic plate theory is needed. The approach used here to obtain such a theory consists in expanding the primal variables into power series in thickness direction. This allows an analytical integration over the thickness, thus reducing the dimension of the problem from 3d to 2d. The resulting out‐of‐plane and in‐plane problems are discussed. Numerical calculations show a good agreement between the proposed model and the three‐dimensional system. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Infinite elements in a poroelastodynamic FEM
Authors: Nenning Mathias , Schanz Martin 
Published: November 2010

AbstractWave propagation phenomena in unbounded domains occur in many engineering applications, e.g., soil structure interactions. When simulating unbounded domains, infinite elements are a possible choice to describe the far field behavior, whereas the near field is described through conventional finite elements. Finite element formulations for porous materials in terms of Biot's theory [1] have been published, e.g., by Zienkiewicz [2]. For infinite elements, several approaches are described in [3,4]. Infinite elements are based on special shape functions to approximate the semi‐infinite geometry as well as the Sommerfeld radiation condition, i.e., the waves decay with distance and are not reflected at infinity. If there is only one wave traveling in the media, a formulation in time‐domain can be established. But in poroelastodynamics, there are three body waves and eventually also a Rayleigh wave. Unfortunately, the extension to more than one wave is not straight forward. Here, an infinite element is presented which can handle all wave types, as it is needed in poroelasticity. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐Order Time Integration in the p‐Version of Finite Elements
Authors: Netz Torben , Hartmann Stefan 
Published: November 2010

AbstractIn isothermal solid mechanics, the space and time domain need to be discretized. This paper presents an approach using high‐order finite elements based on Legendre polynomials for the spatial discretization and time‐adaptive diagonal‐implicit Runge‐Kutta methods for the temporal discretization. The superiority of this approach over a traditional one using linear shape functions for the space domain and a Backward‐Euler scheme for the time domain is demonstrated. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Coupled FE‐Analysis Involving Partially Saturated Soils
Authors: Pertl Michael , Hofmann Matthias , Hofstetter Günter 
Published: November 2010

AbstractA short introduction to the governing equations and the corresponding FE‐formulation of a three phase model for partially saturated soils is given and a constitutive law of the soil skeleton and its numerical integration is discussed briefly. Finally, the application of the numerical model is presented. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Heat conduction in transversally graded laminates with non‐uniform microstructure
Authors: Radzikowska Alina , Jędrysiak Jaroslaw 
Published: November 2010

AbstractTwo‐component laminates made of conductors distributed non‐periodically as laminas along one direction are considered in this note. The macroscopic properties of these laminates are described by continuous slowly‐varying functions across laminas. In order to analyse heat conduction, the approach, called the tolerance modelling, is used. The aim of this note is to use averaged equations of the tolerance model for transversally graded laminates to analyse stationary heat conduction across laminas. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Computation of the Three‐Dimensional Stress State in Composite Shell Structures with Mixed Finite Elements
Authors: Schürg Marco , Wackerfuß Jens , Gruttmann Friedrich 
Published: November 2010

AbstractBeing able to compute the complete three‐dimensional stress state in layered composite shell structures is essential in order to examine complicated interlaminar failure modes such as delamination. We lay out a mixed finite element formulation with independent displacements, rotations, stress resultants and shell strains. A mixed hybrid shell element with 4 nodes and 5 or 6 nodal degrees of freedom is developed, so that the element formulation can also be used for problems with shell intersections. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Least‐Squares Mixed Finite Element for Quasi‐Incompressible Elastodynamics
Authors: Schwarz Alexander , Steeger Karl , Schröder Jörg 
Published: November 2010

AbstractIn the present work, a mixed finite element based on a modified least‐squares formulation is proposed. Here, we consider the time‐dependent equations for quasi‐incompressible elastodynamics under small strain assumptions. The main goal is to obtain an accurate approximation of both displacements and stresses in particular for the lowest‐order element. Basis for the element formulation is a weak form resulting from a least‐squares method. The L2‐norm minimization of the time‐discretized residuals of the given first‐order system leads to a functional depending on approximations for displacements and stresses. By introducing a time‐independent displacement test function, a weak form is derived. A numerical example concerning quasi‐incompressible elasticity shows the performance of the approach for the lowest‐order element RT0P1as. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Minimum Stiffness Criteria for Edge Reinforcements of Elastically Clamped Plates
Authors: Weißgraeber Philipp , Mittelstedt Christian , Becker Wilfried 
Published: November 2010

AbstractIn many structural situations, e.g. in aerospace engineering, composite plates with edge reinforcements are used, for example as stiffeners of a fuselage section of an airplane. Based on an explicit analysis of the buckling behavior of the laminate plate, a minimum stiffness criterion is presented in this contribution. A transformation of the governing equations into a dimensionless system is used, that proved to be very advantageous. Besides a minimum stiffness criterion that can be used for generation of minimum stiffness diagrams, an absolute minimum stiffness is found that enables the reinforcement to act like a simple support for arbitrarily slender plates. The relevance of the criteria for stiffener design is discussed. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamical flexibility of damped vibratory clamped‐clamped beam in transportation
Authors: Żółkiewski Sławomir 
Published: November 2010

AbstractThis work concerns the issue of damped vibratory beam in transportation. Support conditions were defined for clamped‐clamped beamlike systems. Structural loads were defined as with unitary amplitude ones up to the used dynamical flexibility definition. Geometric representation of analyzed element is a beam with symmetric cross‐section constant on the whole length of the beam. The load assumed as bending one. The beam was fixed onto the rotational disk with the angular velocity treated as transportation velocity. In thesis the dynamical flexibility of analyzed beam was presented and the sample dynamical characteristics were drawn on graphical charts. In derived mathematical model mutual interactions between the damping forces, dynamical flexibilities and angular working velocity were took into consideration. Presented model can be put into use in high speed pumps and turbines as vanes. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stability and Bifurcations of Rotors in Fluid Film Bearings
Authors: Boyaci Aydin , Seemann Wolfgang , Proppe Carsten 
Published: November 2010

AbstractTo study the nonlinear phenomena of rotors in the sense of bifurcation theory, the mechanical model of a symmetric flexible rotor is investigated which is supported by two identical journal bearings. Two types of journal bearings are considered. While the oil whirl and oil whip oscillations of rotors in plain journal bearings are widely examined, the floating ring bearings cause a quite different vibration behavior with several mode interactions and an area of so‐called critical limit cycles leading to a rotor damage. For both types a Hopf bifurcation marks the beginning of the self‐excited oscillations in the case of a perfectly balanced rotor. By applying the methods of numerical continuation the occurring limit cycles as well as their stability are determined. The different nonlinear effects with the corresponding bifurcations are explained by describing the global solution behavior of the rotor‐bearing systems. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the Transverse Vibrations of a String Segment Between Two Supports Moving Axially Along a String of Infinite Length
Authors: Franze Andreas , Zastrau Bernd W. 
Published: November 2010

AbstractThis paper deals with the equation of motion of a string with time‐varying boundary conditions. This equation can be transformed to a partial differential equation (PDE) with non‐varying boundary conditions. During the solution process, the inverse of the time derivative operator is needed. To ensure the existence of a solution, the time derivative is generalized to a weighted time derivative on a weighted L2‐space. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bifurcation analysis of a stochastic non‐smooth friction model
Authors: Gaus Nicole , Proppe Carsten 
Published: November 2010

AbstractNon‐smooth systems with stochastic parameters are important models e.g. for brake and cam follower systems. They show special bifurcation phenomena, such as grazing bifurcations. This contribution studies the influence of stochastic processes on bifurcations in non‐smooth systems. As an example, the classical mass on a belt system is considered, where stick‐slip vibrations occur. Measurements indicate that the friction coefficient which plays a large role in the system behavior is not deterministic but can be described as a friction characteristic with added white noise. Therefore, a stochastic process is introduced into the non‐smooth model and its influence on the bifurcation behavior is studied. It is shown that the stochastic process may alter the bifurcation behavior of the deterministic system. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vibrational asperity interaction in slowly sliding contacts
Authors: Graf Matthias , Ostermeyer G.‐P. 
Published: November 2010

AbstractWhen two elastic bodies slide against each other, contacting asperities carry tangential load. In the case of slow sliding, each asperity can show a stick‐slip‐like movement that can be modelled as an integrate‐and‐fire (IF) oscillator. Asperities influence each other by an elastic coupling which allows a globally synchronized state instead of local events. For two neighboured asperities, the dynamics of coupled IF oscillators is investigated in view of synchronization modes, energy dissipation and their significance for the tribological contact. Additionally, the influence of a relaxating coefficient of stiction, i.e. a time‐dependent firing threshold, is discussed. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Untersuchung des Schwingungsverhaltens von Ölgemälden
Authors: Kracht Kerstin , von Wagner Utz 
Published: November 2010

AbstractGemälde der „Alten Meister“ sind unersetzbare Kulturgüter, die von hohem künstlerischen, kulturellen, ethisch‐religiösen, historischen, sozialen und/oder ökonomischen Wert sind. Daher hat der Schutz der Kunstwerke vor Beschädigungen höchste Priorität. Das große Interesse der Öffentlichkeit an Kulturgütern, wie den Ölgemälden, erfordert die Ausstellung der Gemälde und damit auch ihren Transport. Gemälde werden jedoch während der Exposition und des Transportes schädlichen, dynamischen Beanspruchungen ausgesetzt, was im Widerspruch zum Schutzbedarf steht. Da sich Ausstellungen und Transporte nicht vermeiden lassen, haben Restauratoren im Vorfeld die Aufgabe die Gemälde zu beurteilen, inwiefern diese den anstehenden Belastungen standhalten werden. Die Beurteilungskriterien sind subjektiver Natur und basieren auf sichtbaren Alterungsphänomenen.Die vorliegende Veröffentlichung diskutiert die Ergebnisse experimenteller Schwingungsanalysen an speziellen Testobjekten, die nach „Art der Alten Meister“ hergestellt wurden. Grundlagen der Resultate sind Schwingungsantworten frischer und gealterter Ölgemälde, die mit Hilfe berührungsloser Lasertechnik gemessen wurden. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical Solution of the Fokker‐Planck Equation with Time‐Discontinuous Galerkin Methods
Authors: Loerke Friederike , Nackenhorst Udo 
Published: November 2010

AbstractThe response of non‐linear dynamic systems under white noise excitation possesses Markov characteristics. The evolution of the probability density of the system response is represented by the Fokker‐Planck equation, which characterizes advection and diffusion. The solution probability density distribution often possesses high gradients. Therefore an efficient numerical solution technique based on a discontinuous Galerkin approximation in the time domain is proposed for the solution of the Fokker‐Planck equation. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)