bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chaotic vibrations in nonlinear problems of bar structures
Authors: Koszela P. , Napiorkowska‐Alykow M. 
Published: January 2007

AbstractIn the response of nonlinear mathematical models which describe vibrations of structural elements one could observe an irregular behaviour which is called chaos. Loss of the information on initial states in deterministic dynamical systems after a short time of theirs evolution, increasing amplitudes of displacements, velocities and accelerations, sensitive dependency on initial conditions makes chaos dangerous phenomenon in mechanics of construction. In this article quantitative (bifurcation diagrams, Poincare sections and Fourier power spectrum analysis) identication methods of the chaotic dynamics in geometrically nonlinear model of one DOF Mises truss are shown. Main goal of this article is to show and verify dangerous influence of chaos (in the engineering sense) on the analyzed structure. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stability problems of textile wound structures
Authors: Kyosev Yordan , Reinbach Ingo , Gries Thomas 
Published: January 2007

AbstractMathematical model for calculation of the stress‐strain behavior of the wound package is presented. It uses the split of the body of cylindrical layers with finite thickness under assumption for orthotropic, linear elastic behavior of the single layers. The numerical results demonstrate, that in certain cases the windings and layers lose their tension forces, where the winding package loses its stability. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Finite strain model for contact interface in forming processes
Authors: Luege Mariela , Luccioni Bibiana M. 
Published: January 2007

AbstractA phenomenological rate and state‐variable friction law for the continuous sliding under lubricated and dry conditions, as it occurs in metal forming processes, is presented in this paper. The contact model is developed within the framework of continuum thermodynamics of irreversible processes with internal variables and for large strains assuming the contact area as a material surface. The model reproduces the experimental boundary friction map obtained by Luengo et al [1]. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Coherence of Structural Optimization and Configurational Mechanics
Authors: Materna Daniel , Barthold Franz‐Joseph 
Published: January 2007

AbstractThis contribution is concerned with the similarities of structural optimization and configurational mechanics. In structural optimization sensitivity analysis is used to obtain the sensitivity of continuum mechanical functions with respect to variations of the material body, i.e. the reference configuration. In the same manner in configurational mechanics we are interested in changes of the material body, e.g. crack propagation or phase transition problems. Consequently, variational design sensitivity analysis and the numerical techniques from structural optimization are applicable to problems fromconfigurational mechanics. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Symmetric and Asymmetric Underplatform Dampers for Turbine Blades
Authors: Panning Lars 
Published: January 2007

AbstractFriction damping devices like underplatform dampers are widely used in turbomachinery applications to reduce vibration amplitudes and to increase lifetime and reliability of the bladed disk. Nowadays, in practical applications, a variety of different underplatform damper geometries is applied. Nevertheless, a detailed study of the in.uence of the geometric and dynamic properties of the damper is still not available. Within this paper the most frequently applied damper types like cylindrical and wedge as well as asymmetrical dampers are investigated and compared to each other with respect to their effectiveness. Especially the in.uence of the damper geometry on the resonance frequency and vibration amplitude is pointed out. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Variational Approaches in the Beam Theory
Authors: Vasily Saurin , Georgy Kostin 
Published: January 2007

AbstractEquations governing the stress‐strain state of an elastic beam are derived on the basis of the method of the integro‐differential relations (IDR). The influence of Poisson's ratio and shear modulus on the stiffness characteristics of an elastic beam with a rectangular cross section is investigated. Explicit expressions are obtained for the stress fields in an isotropic or anisotropic beam for an arbitrary type of loading. A system of differential equations for displacement fields in these beams is presented. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Size Effects at Corners of Anisotropic Material Discontinuities
Authors: Wigger Hubertus Michael , Becker Wilfried 
Published: January 2007

AbstractReinforcement patches of composite laminates often possess corners due to design and manufacturing necessities. Hence, the patches reconstitute the demanded effective strength or stiffness in the region considered but at their boundaries also constitute a source for stress localizations. The complex potential method is a means for the investigation of such stress localizations. With the help of appropriate complex potentials the mechanical in‐plane fields around the reinforcement corner can be expressed as series representations. A first analysis step is to obtain the exponents and corresponding modes which cause singular behavior of the membrane forces. Then, the determination of appropriately defined generalized membrane force intensity factors is used to show whether and how the singularity exponents are in effect. On this basis it is possible to deduce what impact a specific loading condition or the reinforcement corner's material combination and geometry have on the character of the singularity. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Contact of fractal surfaces – Experimental and numerical results
Authors: Willner Kai , Görke Daniel 
Published: January 2007

AbstractMeasurements of rough surfaces show that the roughness topography can be described as a fractal over several length scales. A suitable description is then given by a discrete structure function. For a large class of typical surfaces measured structure functions can be approximated by a three‐parameter function, employing the rms‐value of the roughness, a transition length between fractal behavior at high wavenumbers and stationary behavior at low wavenumbers, and the fractal dimension in the fractal region, respectively, as intrinsic parameters to describe an isotropic rough surface.To study the normal contact behavior of such fractal surfaces numerically, the first author presented in [1] a numerical model which allows to describe the elasto‐plastic normal contact of isotropic fractal surfaces. This model is now tested against experimental data which are obtained from contact tests of several aluminum specimens. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonlinear flexural vibrations of composite shallow open shells
Authors: Adam Christoph 
Published: January 2007

AbstractThis paper addresses geometrically nonlinear flexural vibrations of open doubly curved shallow shells composed of three thick isotropic layers. The layers are perfectly bonded, and thickness and linear elastic properties of the outer layers are symmetrically arranged with respect to the middle surface. The outer layers and the central layer may exhibit extremely different elastic moduli with a common Poisson's ratio ν. The considered shell structures of polygonal planform are hard hinged supported with the edges fully restraint against displacements in any direction. The kinematic field equations are formulated by layerwise application of a first order shear deformation theory. A modification of Berger's theory is employed to model the nonlinear characteristics of the structural response. The continuity of the transverse shear stress across the interfaces is specified according to Hooke's law, and subsequently the equations of motion of this higher order problem can be derived in analogy to a homogeneous single‐layer shear deformable shallow shell. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Wirkung von Störungen auf die Stabilität von Seilschwingungen
Authors: Aps Ulrich , Thalheim Jens‐Uwe , Heinen Anton 
Published: January 2007

AbstractInstabilitätserscheinungen bei Seilen lassen sich numerisch simulieren durch Aufbringen einer sehr kleinen Störverschiebung auf die Grundschwingung. Es werden die Auswirkungen unterschiedlicher Störeinflüsse untersucht. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hoisting Manipulation for Flying Cranes
Authors: Bockstedte Andreas , Kreuzer Edwin 
Published: January 2007

AbstractA control strategy for hoisting drives of crane systems is discussed. Based on modal coupling control, the desired hoisting velocity is manipulated by superposition of a suitably modulated motion in order to suppress the so–called spaghetti–problem of hoisting–induced pendulations. For a 3–dimensional multibody system featuring the flying–crane –concept the extension of this control strategy to more complicated systems is exemplified. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rolling Contact Problem with the Generalized Coulomb Friction
Authors: Chudzikiewicz Andrzej , Myslinski Andrzej 
Published: January 2007

AbstractThis paper deals with the numerical solution of the wheel ‐ rail rolling contact problems. The unilateral dynamic contact problem between a rigid wheel and a viscoelastic rail lying on a rigid foundation is considered. The contact with the generalized Coulomb friction law occurs at a portion of the boundary of the contacting bodies. The Coulomb friction model where the friction coefficient is assumed to be Lipschitz continuous function of the sliding velocity is assumed. Moreover Archard's law of wear in the contact zone is assumed. This contact problem is governed by the evolutionary variational inequality of the second order. Finite difference and finite element methods are used to discretize this dynamic contact problem. Numerical examples are provided. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Track–Monitoring of Wheel–Rail–Systems
Authors: Glösmann Philipp , Kreuzer Edwin 
Published: January 2007

AbstractInspection and maintenance of railway networks is a complex and expensive task. Special measurement vehicles are used to record the geometrical properties of railway lines within required time intervals. Due to the extent of measurement data the quality of railway track is evaluated considering only a few parameters. Although safety and comfort of wheel–rail–systems depend on the dynamical behavior, current inspection vehicles are not equipped to measure dynamic properties.In this paper, we will discuss a novel approach to evaluate the quality of railway tracks based on wheel–rail dynamics: Wheelset dynamics of subway trains are analyzed by Karhunen–Loève Transformation to extract the principal dynamics from the collected measurement data. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spatial Random Material Property Model for Vibration of Composites
Authors: Machina Gangadhar , Zehn Manfred W. 
Published: January 2007

AbstractInvestigation of vibration and buckling of thin walled composite structures is very sensitive to parameters like uncertain material properties and thickness imperfections. Because of the manufacturing process and others, thin walled composite and other structures show uncertainties in material properties, and other parameters which cannot be reduced by refined discretization. These parameters are mostly spatial distributed in nature. Here I introduce a semivariogram type material property model to predict the spatial distributed material property (like young's modulus) over the structure. The computation of semivariogram parameters needs the local material properties over a prespecified gird. The material properties at each grid have been obtained by considering a statistically homogeneous representative volume element (RVE) at each gird. According to random nature of the spatial arrangement of fibers, the statistically homogeneous RVE is obtained using image processing. The effective material properties of the RVE have been obtained numerically with the help of periodic boundary condition. The methodology is applied to a composite panel model and modal analysis has been carried. The results of the modal analysis (eigen values and mode shapes) are compared with experimental modal analysis results which are in good agreement. Using the presented material property model we can better predict the vibration characteristics of the thin walled composite structures with the inherent uncertainties. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of critical motions of floating structures
Authors: Pick Marc‐André , Kreuzer Edwin , Wagner Jörg 
Published: January 2007

AbstractValidation of numerical methods for describing the motion of a ship in sea conditions by adequate experiments is a major research field in ocean engineering. For the development of a method for the systematic determination of critical and safe operational conditions and for the classification of capsize scenarios bifurcation analyses are performed. The computational effort for these analyses is enormous using a full model describing the nonlinear dynamics of a floating body. Therefore, a method for model reduction is currently being developed at the Institute of Mechanics and Ocean Engineering at TUHH. Bases for the validation of this new method are experiments conducted in the institute's wave tank. The determination of position and attitude of the body is performed with an integrated measurement system: An inertial measurement unit and a video system are combined using an extended Kalman Filter. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vibration Analysis in Mechanical and Medical Engineering
Authors: Reicke L. , Kröger M. 
Published: January 2007

AbstractThis contribution gives an introduction to time‐frequency analysis. A comparison of the basic principles of linear timefrequency analysis explains, in what kind of applications the short‐time fourier transform (STFT) is superior to wavelet transforms. Subsequently, the STFT is performed on signals of mechanical and medical origin to illustrate its potential with regard to vibration analysis. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Three‐Dimensional Simulation of a Circulating Monocable Ropeway
Authors: Renezeder Hans C. , Steindl Alois , Troger Hans 
Published: January 2007

AbstractWe investigate the practically interesting case of ‘sag‐oscillations’ of circulating monocable ropeways using a simple but very instructive three‐dimensional Finite Element model with two cable spans and discuss the qualitative results. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On Paper Machine Roll Contact with Beating Vibrations
Authors: Yuan L. , Järvenpää V.‐M. 
Published: January 2007

AbstractBeating vibration phenomenon observed in paper machine roll units is studied. An analytical model of a roll system is described and an expression for the beating frequency is derived. Numerical results are compared to measurements and conclusions are made based on the observations. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vibration Analysis of Gyroscopic Systems
Authors: Zwiers U. , Braun M. 
Published: January 2007

AbstractMechanical structures which can vibrate about a state of mean rotation or translation may constitute gyroscopic dynamic systems that are related by the mathematical similarity of their governing equations of motion. Considering as examples a rotating circular ring and an axially travelling string, the analogy of those systems is demonstrated. The linear vibrations obtained by superposing small perturbations on the stationary solution are analyzed. Assuming time‐varying speeds, the effect of non‐constant stress resultants on the dynamic stability of gyroscopic systems is investigated and the results are compared to those found in literature where the stress resultants of axially moving continua are commonly taken as constant. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Parameteridentification of Hostun‐Sand and Shear‐Band Simulation of Landsliding
Authors: Avci O. , Ehlers W. 
Published: January 2007

AbstractThe simulation of deformation process of landsliding needs the knowledge of the very complex behaviour of granular materials, e. g., sand. The triax experiments on sand show a highly non‐linear elasto‐plastic material behaviour. Therefore, it is necessary to use a yield criteria, e. g., single‐surface yield criteria with isotropic hardening and non‐associated plastic potential, which satisfies adequately the requirements of the material properties.This kind of material behaviour can be described by an elasto‐plastic material law in the frame of Theory of Porous Media, which is implemented in the FE tool PANDAS. By means of the data of Hostun‐Sand, the material parameters of the singlesurface yield criteria are determined by use of a optimization algorithm, namely Sequential Quadratic Programming (SQP) a gradient based optimization method, which is coupled with PANDAS. Using this optimized material parameters, a simulation of a initial boundary‐value problem of landsliding is presented. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling and Simulation of the Portevin‐Le Chatelier Effect
Authors: Bertram Albrecht , Böhlke Thomas , Brüggemann Carina , Estrin Yuri , Lebyodkin Mikhail 
Published: January 2007

AbstractDuring deformation of an Al‐Mg alloy (AA5754) dynamic strain aging occurs in a certain range of temperatures and strainrates. An extreme manifestation of this phenomenon, usually referred to as the Portevin‐Le Chatelier (PLC) effect, consists in the occurrence of strain localisation bands accompanied with discontinuous yielding. The PLC effect stems from dynamic dislocation‐solute interactions and results in negative strain‐rate sensitivity of the flow stress. The PLC effect is detrimental to the surface quality of sheet metals and also affects the ductility of the material. Since the appearance of the effect strongly depends on the triaxiality of the stress state, three‐dimensional finite element simulations are necessary in order to optimize metal forming operations. We present a geometrically nonlinear material model which reproduces the main features of the PLC effect. The material parameters were identified based on experimental data from tensile tests. Special emphasis was put on the critical strain for the onset of PLC effect, ε c , and the statistical characteristics of the stress drop distribution. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simulation of strain induced austenite‐martensite transformation
Authors: Bontcheva Nikolina , Petrov Peter , Petzov Georgi , Parashkevova Ludmils 
Published: January 2007

AbstractGrain refinement due to phase transformation is an effective method for improving the mechanical properties of steel. An approach is proposed in the present work based on the FEM, for numerical simulation of the microstructure evolution as a result of hot rolling and subsequent cold torsion. Grain refinement in 304 stainless steel at four different technological schedules is considered. Results of numerical simulation are compared with experimental data. Coupling of the thermoplastic deformation with microstructure evolution is realized. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Materialmodelling of shape memory alloys in range of large deformations
Authors: Christ Daniel , Reese Stefanie 
Published: January 2007

AbstractIn this contribution we present a finite deformation material model for SMA which includes the effect of pseudoelasticity. The model's structure is similiar to a Frederick‐Armstrong type hardening model for elastoplasticity. A special algorithm has been developed to incorporate the concept into a FE code. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dual reciprocity BEM for dynamic piezoelectricity
Authors: Dziatkiewicz Grzegorz , Fedelinski Piotr 
Published: January 2007

AbstractThe piezoelectric phenomenon is widely utilized in many devices. An analysis of piezoelectric devices requires a solution of coupled mechanical and electrical partial differential equations. In this paper the boundary element method (BEM) is implemented to solve the eigenvalue two‐dimensional problem of linear piezoelectricity. The piezoelectric material is modeled as: homogenous, transversal isotropic, linear elastic and dielectric. The numerical solution by the BEM requires fundamental solutions,which are derived using the Stroh formalism. The mass matrix of piezoelectric is computed by the dual reciprocity BEM. A numerical example shows that the dual reciprocity BEM formulation allows to analyze accurately dynamic problems of linear piezoelectricity. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Computational Material Forces in Micromorphic Continua
Authors: Hirschberger C. Britta , Kuhl Ellen , Steinmann Paul 
Published: January 2007

AbstractThe micromorphic continuum theory is used to describe materials with significant microstructure which thus exhibit scaledependence (see e.g. [1], [2] [3]). Microcontinua are assumed to be attached to each physical point and may experience both stretch and rotation which are affine throughout the microcontinuum, nevertheless kinematically independent from the deformation on the macroscale. The additional kinematical quantities which account for the micro‐deformation yield additional stresses and contributions to the balance of momentum. Additionally to the common finite‐element approximation which here is a coupled problem to be solved for macro‐ and the micro‐quantities, we apply the method of material forces, cf. [4], [5]. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling and simulation of extrusion of aluminum alloys
Authors: Kayser Tobias , Hortig Christian , Svendsen Bob 
Published: January 2007

AbstractThe purpose of this work is the modeling and simulation of the material behavior of aluminum alloys during extrusion, cooling and metal forming processes. In particular, the alloys of the 6000 series (Al‐Mg‐Si) and 7000 series (Al‐Zn‐Mg) are relevant here. Under the corresponding conditions, their behavior is controlled mainly by dynamic recovery during the extrusion and static recrystallization during cooling. The current material model is based on the role of the energy stored in the material during extrusion as the driving force for microstructural evolution. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experiments and Identifications for Finite Polymer Inelasticity
Authors: Méndez Joel , Göktepe Serdar , Miehe Christian 
Published: January 2007

AbstractThe constitutive theories intended to quantitatively account for the complicated material response exhibited by polymers include, in general, adjustable material parameters. These must be identified from experimental data obtained from the material under consideration. This contribution presents the complete procedure studying the behavior of polymers at large strains in three basic steps: i) Accomplishment of homogeneous and 3‐D inhomogeneous experiments under different deformation conditions. ii) Identification of the material parameters of a constitutive model by means of gradient–based optimization methods with respect to the homogeneous experimental data. iii) Validation of the identified material parameters by comparing 3‐D FE simulations to the inhomogeneous experimental data. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)