bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reibungsdämpfung in ausgedehnten, verschraubten Fügestellen
Authors: Hölzl Johannes Sebastian , Sextro Walter 
Published: November 2010

AbstractBei der Konstruktion von Maschinen ist es oftmals erforderlich, Schwingungen minimal zu halten. Um z.B. die Lebensdauer zu erhöhen, Material einzusparen oder den Geräuschpegel gering zu halten muss oft ein großer Aufwand zur Dämpfung von auftretenden Schwingungen betrieben werden. In vielen technischen Anwendungen werden Einzelteile miteinander verschraubt. Diese Fügestellen können gezielt und mit wenig Aufwand zur Schwingungsdämpfung herangezogen werden. Die Berechnung des dynamischen Verhaltens verschraubter Strukturen stellt immer noch eine Herausforderung dar. Es wurde eine Methode entwickelt, um den eingeschwungenen Zustand elastischer, miteinander verschraubter Körper mit rauen Fügestellen bei periodischer Anregung zu berechnen. Als Basis dienen Finite Elemente Modelle der einzelnen Teile, deren Freiheitsgrade durch modale Kondensation reduziert werden. Unter Anwendung des Verfahrens von Ritz und Galerkin wird eine Näherungslösung für den eingeschwungenen Zustand des nichtlinearen, gekoppelten Systems ermittelt. Abhängig von den Schraubenvorspannkräften sowie den bestimmenden Parametern der Kontaktflächen, Rautiefe und Reibungskoeffizient, kann die Systemantwort berechnet und optimiert werden. Um die Berechnungsmethode zu verifizieren wurden Experimente durchgeführt. Der Vergleich zwischen Messung und Rechnung zeigt eine gute Übereinstimmung. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Integrodifferentialgleichungen in der Analyse innerer Dynamik von Planetengetrieben
Authors: Hortel Milan , Škuderová Alena 
Published: November 2010

AbstractGenauere dynamische Analyse von hochtourigen Planetengetrieben führt auf mathematisch‐physikalische Modelle, deren Bewegungen bei Anwendung der Massendiskretisierung durch deterministische gewöhnliche nichtlineare zeitlich heteronome Differentialgleichungen beschrieben werden. Diese Systeme von n Freiheitsgraden können ein breites Spektrum von Eigenschaften aufweisen, das von regulären periodischen bis zu irregulären Lösungen vom chaotischen Charakter reicht. Zur dynamischen Analyse solcher komplizierter Systeme wurde ein sukzessives Approximationsverfahren der zur Differentialrandwertaufgabe äquivalenten Integrodifferentialgleichungen mit lösenden Kern in Form von einer Greenschen Resolvente angewendet. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of Dynamical Responses for the MDF Wooden Material
Authors: Litak Grzegorz , Scheffler Michael , Morgenstern Gunnar 
Published: November 2010

AbstractThe nonlinear analysis have been performed on the experimental data of a beam vibration composed of a wooden material MDF (Medium‐Density Fiberboard). Firstly, the beam was subjected to the harmonic excitation on the clamp with its first eigenfrequency. After reaching the eigenfrequency, the excitation was switched of and the velocity amplitudes were measured. To identify the frequencies and the damping of vibrations, we applied nonlinear methods including Hilbert transform and wavelets. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the Solution of High Dimensional Fokker Planck Equations using Orthogonal Polynomial Expansion
Authors: Martens Wolfram , von Wagner Utz 
Published: November 2010

AbstractSolving the Fokker‐Planck‐Equation for multidimensional nonlinear systems is a great challenge in the field of stochastic dynamics. As for many mechanical systems a general idea about the shape of stationary solutions for the probability density function is known, it seems promising to use an approach that contains this knowledge. This is done using a Galerkin‐method which applies approximate solutions as weighting functions for the expansion of orthogonal polynomials, e.g. generalized Hermite polynomials [1]. As examples, nonlinear oscillators containing cubical restoring (Duffing oscillators) and cubical damping elements are considered. The method is applied to the two‐dimensional problem of a single‐degree‐of‐freedom oscillator and consecutively extended up to dimension ten. Results for probability density functions are presented and compared with results from Monte Carlo simulations. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonlinear Behavior of Piezoceramic Actuators
Authors: Nguyen Huy The , von Wagner Utz 
Published: November 2010

AbstractNonlinear behavior of piezoceramics is a well‐known phenomenon. For large stresses and/or strong electric fields it is described by various hysteresis curves. Quasi‐static experiments exhibited hysteresis relations between excitation voltage and strain as well as between excitation voltage and electric displacement. This behavior can be modeled by using the classical Preisach model. On the other hand, typical nonlinearities of Duffing type such as jump phenomena, multiple stable amplitude responses at the same excitation voltage and frequency, and the presence of superharmonics in response spectra can be observed when piezoceramic actuators are excited near resonance, even at weak electric fields. In this paper, different experimental results for both quasi‐static and dynamic nonlinear behavior and corresponding models are presented and compared. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nichtlineares Kontaktmodell für die Schleif‐Prozess‐Simulation
Authors: de Payrebrune Kristin M. , Kröger Matthias 
Published: November 2010

AbstractDie Herstellung von Hochleistungswerkzeugen aus Hartmetall, wie Bohrern oder Schaftfräsern, ist sehr aufwändig und aufgrund der hohen Härte des Materials nur durch Schleifprozesse realisierbar. Um den Schleifprozess zu optimieren ist die Simulation der Schwingungen während des Prozesses in den Fokus der Wissenschaft gerückt. Besonders die Wechselwirkungen zwischen Werkstück, Schleifprozess und Maschinenstruktur werden in diesem Zusammenhang eingehend untersucht, da sie die Qualität der Werkstücke beeinflussen.Um die Prozess‐Struktur‐Wechselwirkungen, hervorgerufen durch den nichtlinearen Kontakt zwischen Schleifscheibe und Werkstück, zu untersuchen werden am Institut für Maschinenelemente, Konstruktion und Fertigung grundlegende Analysen von Schleifprozessen durchgeführt und die Ergebnisse in einen Modellierungsansatz für diese Fertigungsprozesse implementiert. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Active Vibration Control of Roll Press System by Piezoelectric Actuators
Authors: Töhönen Mika , Seemann Wolfgang 
Published: November 2010

AbstractA common treatment in manufacturing web‐like thin materials like paper is to manipulate it between two cylinders under rolling contact. A roll press is sensitive to vibration, which is unwanted, because it marks the web by regular stripes. A piezoelectric actuator is an excellent device for vibration control applications because of its large force generation, very short response time and easy controllability. Control of piezoelectric actuator is straightforward by direct compensation of input voltage. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the Nonlinear Vibration Behavior of Elastohydrodynamic Contacts
Authors: Wiegert Benedikt , Deppler Jens , Hetzler Hartmut , Seemann Wolfgang 
Published: November 2010

AbstractThe nonlinear dynamic behavior of a simple system with an elastohydrodynamic line contact is investigated. The elastohydrodynamic problem is solved with finite differences including streamline upwind techniques. The results are stored in a lookup table for an effective calculation of the frequency response. It is found that the system exhibits rich nonlinear dynamic behavior including jump phenomena as well as sub‐ and superharmonic bifurcations. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Untersuchung irreversiblen Materialverhaltens mithilfe eines auf thermodynamischen Prinzipien basierenden Ansatzes
Authors: Müller Wolfgang H. , Abali B. Emek 
Published: November 2010

AbstractBekanntlich verwendet man in der Materialwissenschaft „Prinzipe“, um die mögliche Form von Materialgleichungen einzuschränken. Insbesondere sind hier das Entropieprinzip (etwa in der Version der Thermodynamik irreversibler Prozesse (TIP) nach [1], der Clausius‐Duhem Formalismus nach [2] oder die Methode der Lagrange‐Multiplikatoren [3]) zu nennen. Darüber hinaus existieren Extremalprinzipe, also „Derivate“ des Entropieprinzips, etwa das Prinzip der minimalen Energiedissipation nach [4] oder das Prinzip der maximalen Entropieproduktionsrate (bzw. Dissipationsrate) nach [5]. Langfristig gesehen ist es unser Ziel, die Zusammenhänge zwischen diesen auf den ersten Blick unabhängigen Postulaten aufzuzeigen. Kurzfristig geht es in diesem Artikel darum, ein konkretes Randwertproblem zu studieren, an dem sich erstens die Entropieproduktionsrate explizit berechnen und ihre Maximaleigenschaften diskutieren lassen und zweitens der Übergang zwischen nichtlinear‐reibungsbehafteter Flüssigkeit zum starr‐plastischen, linear verfestigenden Festkörper vornehmen lässt. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental Investigation, Viscoelastic‐Plastic Modelling and Parameter Identification for Different Batches of 51CrV4 Steel
Authors: Al‐Baldawi Ammar , Schreiber Lothar , Wünsch Olaf 
Published: November 2010

AbstractIn this paper, differences of the mechanical behaviour of several batches of 51CrV4 are shown in elongational controlled tests. The consequences of modelling the behaviour are treated with a viscoelastic‐plastic model. For each batch, a new parameter set was obtained using an evolution based optimization strategy. Here, the average parameter set is shown to be inaccurate in case of using it for all batches. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Hybrid Micro­Macro­Model for the Description of Evolving Anisotropy in Finite Polycrystal Plasticity
Authors: Frankenreiter Ilona , Rosato Daniele , Miehe Christian 
Published: November 2010

AbstractThe paper outlines recent developments of an efficient computational micro‐macro modeling of evolving anisotropies in metallic polycrystals. Main focus is put onto large strain deformation processes where the anisotropy is caused by developments of crystallographic texture. We construct a hybrid micro‐macro framework that mixes ingredients of a purely macroscopic modeling with scale bridging operations of selected micromechanisms. On the micromechanical side, we develop a new algorithmic procedure to capture the crystal reorientation for evolving fcc and bcc textures based on a parametrization of rotations in the Rodigues space. The computational model provides a fast and robust method for the estimation of evolving textures. This computational tool for texture estimation is incorporated in a modular format into a micro‐macro‐model, where it governs the evolution of macrostructural tensors due to texture development. The general framework for the hybrid embedding is a purely phenomenological setting of anisotropic finite plasticity in the logarithmic strain space. The model provides an efficient and computationally handable two‐scale approach for the prediction of effects caused by complex microstructural changes in polycrystals. The capability of the proposed method is demonstrated by means of representative numerical examples. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Micromechanical modeling of talc particle reinforced thermoplastic polymers
Authors: Hempel Philipp , Hillenberg Alexander , Seelig Thomas 
Published: November 2010

AbstractThe present work aims at investigating the mechanical behavior of talc particle reinforced thermoplastic polymers. Therefore, micromechanical analyses are performed utilizing detailed finite element models of the explicitely resolved microstructure. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling Metals At Finite Deformation
Authors: Lehmann Eva , Loehnert Stefan , Wriggers Peter 
Published: November 2010

AbstractDuring metal forming processes, substantial microstructural changes occur in the material due to large plastic deformations leading to different mechanical properties. It is of great interest to predict the behaviour of these materials at different fabriction stages and of the final product.At first glance, the behaviour of metals can be approached by an elastoplastic isotropic material model with a volumetric‐deviatoric split and isotropic hardening. In order to perform the calculations, a logarithmic strain is considered in the principal directions of stress and strain space, allowing to make predictions even at finite deformations.Because of the actual nature of metals, the crystalline structure, the deformation at the microstructural level is much more complex. Due to the mathematically algorithmic form of an elastic predictor and a plastic corrector, the elastoplastic model can be extended to crystal plasticity which is similarly handled in terms of a critical resolved shear stress on defined slip planes in the crystal. Hardening can be modelled through a viscoplastic power law. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the variationally consistent modeling of material failure
Authors: Mosler Jörn 
Published: November 2010

AbstractMaterial failure associated with cracks or shear bands is frequently analyzed by utilizing so‐called cohesive models. Such models are based on traction‐separation laws. Within such approaches, the stress vector of the considered crack or shear band is related to its conjugate variable being the respective displacement jump (such as the material separation or the crack opening). In the present work, a framework suitable for the analysis of shear bands is discussed. All models belonging to that framework are consistently derived from thermodynamical principles. Hence, the second law of thermodynamics is automatically fulfilled. Furthermore, a variational principle strongly relying on the postulate of maximum dissipation is elaborated leading finally to a variationally consistent implementation. More precisely, all state variables, together with the unknown deformation mapping, follow naturally from minimizing an incrementally defined potential within the presented algorithmic formulation. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A fully covariant four‐dimensional formulation in material space‐time
Authors: Schnepp Johannes 
Published: November 2010

AbstractA fully covariant formulation for a hyperelastic solid as a four‐dimensional space‐time manifold is presented. It admits arbitrary coordinate transformations mixing space and time. The geometrical structure of the manifold is represented by a tetrad field. A variational formulation is given which uses the tetrad field as extra dependent variables. This formulation is able to describe a homogeneous stress state in a defect‐free crystal lattice. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantification of the evolution of shape storage and recovery in thermally responsive shape memory polymers
Authors: Steeb Holger , Kazakevičiūtė‐Makovska Rasa 
Published: November 2010

AbstractThis study demonstrates the relevance of strain and stress storage/recovery profiles for the thermomechanical behaviour of thermally responsive Shape Memory Polymers (SMPs). It is shown how these experimentally determined profiles may be used for the development, calibration and validation of continuum‐based models describing the shape memory effect in polymeric materials. The presented methodology applies both to small and finite strain deformation problems under the assumption of constant strain and cooling/heating rates. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Two‐mechanism models ­ some aspects of modelling
Authors: Wolff Michael , Böhm Michael , Suhr Bettina 
Published: November 2010

AbstractTwo‐mechanism (or, generally, multi‐mechanism) models have been studied for the last twenty years. Besides one‐mechanism (or “Chaboche”) models, they are a useful tool for modelling inelastic behavior. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling internal erosion of cohesionless soils using a microstructural parameter
Authors: Becker Christian , Kurzeja Patrick , Steeb Holger 
Published: November 2010

AbstractInternal erosion processes are of vital importance for the risk management of geotechnical structures as well as for the understanding of the macroscopic mechanical and hydraulic properties of the subsoil in various man‐made constructions. Here, a 4‐phase continuum model is presented and numerically applied to illustrative applications. The role of interfacial area and related microstructural parameters is addressed. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical Modeling of Finite Nonlinear Visco­Electroelasticity
Authors: Büschel Alexander , Klinkel Sven , Wagner Werner 
Published: November 2010

AbstractPolymeric electroelastic materials, so called electroactive Polymers (EAP) own the characteristic to deform by the application of an electrical field. Dielectric Elastomer (DE) actuators, belong to the group of electroactive Polymers. This type of actuator consists of soft elastomer between compliant and conducting electrodes. For the elastomer often silicones and acrylic elastomers are used. This material show in general a visco‐hyperelastic behavior. Therefore, models which describe large strains and viscoelasticity are required for the calculation of such actuators. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fully Coupled Thermo‐Hydrodynamic Simulation Model for Journal Bearings
Authors: Esmaeili L. , Schweizer B. 
Published: November 2010

AbstractThe isothermal form of Reynolds fluid film equation is used to predict the pressure generation in hydrodynamic journal bearings if temperature effects are neglected. Often, however, temperature effects may be important and cannot be neglected, because oil viscosity significantly varies with temperature. Also, thermal expansion of journal shaft and bearing housing must be taken into account since the bearing clearance changes with increasing temperature. Hence, the Reynolds pressure field equation, the energy equation for the fluid film and the heat transfer equations for journal and bearing housing have to be solved simultaneously. The coupled thermo‐hydrodynamic fluid flow problem is mathematically defined by a system of nonlinear integro‐differential equations. The governing equations are discretized and solved by a finite element approach. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A tetragonal switching model for ferroelectric materials
Authors: Keip Marc‐André , Schröder Jörg 
Published: November 2010

AbstractIn this work a tetragonal material model for ferroelectric materials including a microscopically motivated switching criterion is presented. The resulting formulation is able to describe ferroelectric switching effects on a microscopic scale under consideration of the natural tetragonal structure of the ferroelectric material. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Adjoint Sensitivity Analysis of a Fluid‐Structure Interaction Problem
Authors: Marius Stoia‐Djeska , Carmen Anca Safta , Florin Frunzulica 
Published: November 2010

AbstractA fluid‐structure mathematical model usually includes parameters whose actual values are known only approximately or can vary around some reference values. The objective of the sensitivity analysis is to determine quantitatively the behavior of the responses of a fluid‐structure system locally around a chosen point of the trajectory in the phase‐space of parameters and dependent variables. In this work, the response considered is the total mechanical energy of the structure. The sensitivities with respect to all the parameters the fluid‐structure system depends on are useful in many situations as well as for optimization purposes. We present the theoretical developments necessary for the application of the adjoint sensitivity analysis methods (ASAM) for the fully coupled governing equations of an aeroelastic system. The algorithm is general and can be applied for any kind of fluid‐structure interaction problems. Illustrative numerical examples are presented for the case of typical section with two degrees of freedom. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Finite element methods for strongly‐coupled systems of fluid‐structure interaction with application to granular flow in silos
Authors: Reinstädler Sven , Zilian Andreas , Dinkler Dieter 
Published: November 2010

AbstractA monolithic approach to fluid‐structure interactions based on the space‐time finite element method is presented to investigate stress states in silos filled with granular material during discharge. The thin‐walled silo‐shell is discretized by continuum based, mixed‐hybrid finite elements, whereas the flowing granular material is described by an enhanced viscoplastic non‐Newtonian fluid model. To adapt the mesh nodes of the fluid domain to the structural deformations, a mesh‐moving scheme using a pseudo‐solid is applied. The level‐set‐method involving XFEM is used, including a 4D split algorithm for the space‐time finite elements, in order to describe free surfaces. The method is applied to 3D silo discharges. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Finite deformations of thin shells with piezoelectric sensors and actuators
Authors: Vetyukov Yury 
Published: November 2010

AbstractWe treat coupled electromechanical problem of finite deformations of piezoelectric shells with the help of the direct approach. A shell is considered as a material surface with mechanical degrees of freedom of particles and with an additional field variable, namely electric potential on the electrodes. This results both in the nonlinear system of equations of piezoelectric shells and in the appropriate numerical scheme. Application of the direct approach is preceded with the three‐dimensional asymptotic analysis of a linear electromechanical problem for a non‐homogeneous piezoelectric plate, which provides the constitutive relations for the nonlinear theory. As a sample problem, we present finite element analysis of deformation and local buckling of cylindrical panel, equipped with piezoelectric sensors. The latter influence the mechanical behavior and produce signals, which can be interpreted in terms of structural entities. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Application of a Viscoelastic Material Model in Electro‐Mechanics
Authors: Vogel Franziska , Steinmann Paul , Göktepe Serdar , Kuhl Ellen 
Published: November 2010

AbstractIn this contribution, the numerical modeling of electro‐viscoelastic material is considered. The electro‐mechanical problem formulated in terms of a symmetrized stress tensor is extended to a viscoelastic material model. For the incorporation of the viscosity model, the logarithmic strain space setting is utilized which mimics the small strain setting. Therefore a rheological model for viscosity from the geometrically linear theory can be used. Numerical examples for a typical uniaxial tensile test show the capability of the method to demonstrate typical relaxation and creep behavior. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Chemo‐Thermo‐Mechanics Coupling Applied in Hardened Cement Paste
Authors: Wu Tao , Wriggers Peter 
Published: November 2010

AbstractIn this contribution, the model of concrete deterioration due to alkali silica reaction(ASR) at the microscale is set up. Based on a three‐dimensional micro computer‐tomography, a finite‐element mesh is constructed at the micrometer length scale and 3D coupled Chemo‐Themo‐Mechanics model in hardened cement paste(HCP) accounting for diffusion, heat transport, micro‐crack is developed with staggering method. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)