bluuebunny/crossref_metadata_2025_split huggingface dataset:
Forced nonlinear oscillation of underactuated systems: the balance board example
Authors: Knoll Carsten , Röbenack Klaus 
Published: December 2014

AbstractIn this contribution we consider a mechanical model of the so‐called balance board or “indoboard” system, which is an unstable underactuated mechanical system. Instead of stabilizing one equilibrium point we investigate the asymptotic stabilization of a closed orbit, which results in a nonlinear oscillation. To this end the system is considered in coordinates of the real Jordan normal form, which facilitates the construction of a Control‐Lyapunov function. On this basis, a nonlinear feedback law which renders the periodic orbit asymptotically stable is easily derived via Sontags formula. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonlinear kinematic oscillations of railway wheelsets of general surface geometry
Authors: Antali Mate , Stepan Gabor 
Published: December 2014

AbstractKinematic oscillation of railway wheelsets is investigated in the case of a straight track, focusing on the nonlinear effects of the geometry of wheel and rail profiles. Euler angles are used to describe the motion of the wheelset, the contacting bodies are modelled by two‐parametric rigid surfaces. The surface parameters of the current contact points are followed during the calculations. The curvatures and their variations are also included in the analysis. From the implicit form of the geometric constraints, the dynamics is determined by means of Taylor expansion. Equations of the local nonlinear motion are derived and the qualitative behaviour of the system is given. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Entwicklung einer Schwingungserregereinheit mit piezoelektrischen Aktoren
Authors: Krüger Thomas , Ams Alfons 
Published: December 2014

AbstractIn der Photovoltaik‐ und Halbleiterindustrie ist das Fertigen von Siliziumwafern ein aufwändiger Produktionsschritt. Die Wafer entstehen durch Zerschneiden eines mono‐ oder multikristallinen Siliziumblocks (Ingot). Dabei kommt das Drahttrennläppverfahren zur Anwendung. Mit dem Ziel den Drahtsägeprozess zu verbessern, wird eine Schwingungserregereinheit entwickelt. Das Gerät, betrieben mit piezoelektrischen Aktoren, ermöglicht mehrachsige Schwingungen des Siliziumblocks. Es werden für die Aktoren und die mechanische Konstruktion einzelne Modelle aufgestellt. Durch Messung des Übertragungsverhaltens gelingt anhand des gekoppelten Gesamtmodells die Identifikation von Parametern. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On stability of certain key types of rigid body motion in a nonconservative field
Authors: Shamolin Maxim V. 
Published: December 2014

AbstractIn this activity the qualitative analysis of spatial problems of the real rigid body motions in a resistant medium is fulfilled. A nonlinear model that describes the interaction of a rigid body with a medium and takes into account (based on experimental data on the motion of circular cylinders in water) the dependence of the arm of the force on the normalized angular velocity of the body and the dependence of the moment of the force on the angle of attack is constructed. An analysis of plane and spatial models (in the presence or absence of an additional tracking force) leads to sufficient stability conditions for translational motion, as one of the key types of motions. Either stable or unstable self‐oscillation can be observed under certain conditions. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Higher Order Continuum Modelling for Predicting the Mechanical Behaviour of Solid Foams
Authors: Liebenstein Stefan , Sandfeld Stefan , Zaiser Michael 
Published: December 2014

AbstractA higher order continuum model is presented, which is able to capture size effects and regularize softening in rotational, shearing and especially compressive settings. It is shown that with a minimal setting of 3 additional constitutive parameters the model has all desired properties. For parameter identification an example system of a honeycomb structure is investigated. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A two‐scale simulation framework for Internal Traverse Grinding
Authors: Holtermann Raphael , Menzel Andreas , Schumann Sebastian , Biermann Dirk 
Published: December 2014

AbstractWe present a hybrid framework which aims at the modelling and simulation of Internal Traverse Grinding of hardened 100Cr6/AISI 52100 by using electro plated cBN grinding wheels. We focus on the thermo‐mechanical loading conditions on the workpiece that results from the interaction of workpiece and tool. The modelling framework basically consists of three components, namely representative plane strain adaptive finite element simulations on a meso‐scale, capturing the proximity of a single cBN grain when cutting through the workpiece bulk. Secondly, we incorporate a kinematic simulation on the process level to gain detailed simulation‐based information on the transient grain‐bulk‐interaction. The third component of the framework consists of a macro‐scale process model that uses the superposed results of the former two components as thermo‐mechanical boundary conditions. Using this framework, we target the prediction of metallurgical effects, such as white layers, on the workpiece on the macro scale in the near future. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Boundary value problems in the theory of thermoporoelasticity for materials with double porosity
Authors: Svanadze Merab 
Published: December 2014

AbstractIn this paper the linear quasi‐static theory of thermoelasticity for solids with double porosity is considered. The system of equations of this theory is based on the equilibrium equations for solids with double porosity, conservation of fluid mass, constitutive equations, Darcy's law for materials with double porosity and Fourier's law for heat conduction. The basic internal and external boundary value problems (BVPs) of steady vibrations are formulated. The uniqueness and existence theorems for classical solutions of the above mentioned BVPs are proved by means of the potential method (boundary integral equation method) and the theory of singular integral equations. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling the moisture dependent material behavior of adhesive bonds close to the glass transition temperature
Authors: Goldschmidt Florian , Diebels Stefan 
Published: December 2014

AbstractIn the presented work, a viscoelastic cross‐linked polyurethane is investigated. Environmental influences lead to an inhomogeneous spatial distribution of the mechanical properties in polymer adhesives. Diffusive transport mechanisms transfer water from the environment into the polymer. Further effects like temperature, also have an influence on the mechanical behavior of adhesives. The model respects these influences and takes the incompressibility of the material into account. Viscoelastic behavior can be observed, especially close to the glass transition temperature [3]. Additional to these general effects on polymers, adhesive bonds show a dependency of the mechanical behavior on the thickness of the layer. For numerical investigations, all necessary balance and constitutive equations are implemented in the open‐source C++ finite element code deal.II [1, 2]. With the help of this implementation and by comparing experimental results and results gained from simulations, material parameters of the used polymer can be identified. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Material modelling of a filled rubber material with different approaches in the representation of a statical hysteresis
Authors: Scheffer Tobias , Diebels Stefan 
Published: December 2014

AbstractIn this contribution, two different approaches for the description of an incompressible carbon black‐filled EPDM (ethylene propylene diene monomer) are presented. Regarding the material's behaviour, especially for cyclic loading conditions, a kind of statical hysteresis loop is present. Even for the slowest possible strain rate, a clearly visible hysteresis occurs in loading‐unloading experiments. The first shown model approach is basically a purely viscoelastic description. Because of the non‐linearities in the material behaviour, the material parameters have to be reformulated by complex functions including further parameters that are strongly coupled. This description is able to display very well the behaviour of the EPDM with respect to quasi‐statical experiments, as well as to dynamical tests for moderate strain rates. The major problem of this model liess in the parameter identification. The coupling of the material parameters leads to a difficult, long‐durating and non‐unique identification. Therefore, initial ideas for an alternative description, escpecially concerning the above‐mentioned statical part of the hysteresis, are outlined in this article. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Potential method in the steady vibrations problems of the theory of thermoviscoelasticity for Kelvin‐Voigt materials with voids
Authors: Svanadze Maia M. 
Published: December 2014

AbstractIn this paper the linear theory of thermoviscoelasticity for Kelvin‐Voigt materials with voids is considered. The basic internal and external boundary value problems (BVPs) of steady vibrations are formulated. The uniqueness and existence theorems for classical solutions of the above mentioned BVPs are proved by using the potential method (boundary integral equation method) and the theory of singular integral equations. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A thermodynamically consistent constitutive model for fluid mud
Authors: Hülsmann Anna , Nackenhorst Udo , Wurpts Andreas 
Published: December 2014

AbstractIn this contribution, an approach towards a thermodynamically consistent constitutive model for fluid mud is presented. Fluid mud exhibits highly non‐Newtonian, thixotropic behaviour. It can be classified as a structured fluid. Typically, its viscosity is modeled using Bingham‐type rheological models of different complexity [1, 2]. Here, the three‐dimensional non‐Newtonian constitutive behaviour will be modeled based on a visco‐elasto‐plastic model. At the current stage, a Drucker‐Prager‐like yield function has been formulated. Viscosity is assumed to be a function of shear viscosity. First results show the general ability to represent experimental data. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimum blank design by using the FEM based on inverse motion in orthotropic elasto‐plasticity
Authors: Landkammer Philipp , Germain Sandrine , Steinmann Paul 
Published: December 2014

AbstractInverse form finding aims to determine the optimum blank design of a workpiece whereby the desired end configuration that is obtaining after a forming process, the boundary conditions and the applied loads are known. Inputting the optimal initial configuration a subsequent computation with the Finite Element Method (FEM) then has to result in exactly the nodal coordinates of the desired deformed workpiece. Germain et al. [1] recently presented a new form finding strategy for isotropic elasto‐plasticity, see also Landkammer et al. [2] for orthotropic plasticity. The corresponding algorithm uses the inverse mechanical formulation (also denoted as inverse finite element method) in addition to the common direct formulation in a recursive way. Switching between the direct and the inverse mechanical formulation, while fixing the internal plastic variables in the inverse step, uniquely detects the undeformed configuration iteratively. This contribution demonstrates within an example that the developed recursive algorithm even works with combinations of orthotropic elastic and orthotropic plastic material parameters without affecting the nearly linear convergence rate of the form finding algorithm. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the contact interfaces in sonic composites
Authors: Girip Iulian , Ioan Rodica 
Published: December 2014

AbstractThe paper analyses the effect of normal contact with friction on the generation of full band‐gaps in sonic composites. The behavior of contact interfaces are computed by using LISA (local interaction simulation approach). LISA is an efficient tool for numerical simulation of the acoustic wave propagation in heterogeneous material specimens, in particular those with contact interfaces between different materials, like in sonic composites. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Life Prediction of FRP Composites by a Direct Method
Authors: Hachemi Abdelkader , Vasiukov Dmytro , Panier Stéphane 
Published: December 2014

AbstractA direct computational approach for lifetime prediction of fibre‐reinforced polymer (FRP) composites is presented. The approach is based on a direct method which allows predicting the fatigue life from the stabilised damage state. The classical direct method is generalised to the case of coupled plasticity with damage mechanics of the UD‐FRP composite materials [1]. The constitutive model is based on a continuous damage meso‐scale approach [2]. By analysing damage variables and thermodynamical forces associated with damage at the stabilised state, fatigue life prediction law is proposed as a power law function of stabilised thermodynamic forces. The obtained numerical results have been validated by experimental test results on standard glass‐fibre/epoxy angle‐ply and cross‐ply laminate plates. The proposed approach could serve as a useful tool for the design of FRP composites. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Adaptive textile‐reinforced composites: Modeling and application
Authors: Linse Thomas , Ulbricht Volker , Kluge Axel , Cherif Chokri 
Published: December 2014

AbstractThe scope of the present paper is the modeling of the mechanical behavior of textile‐reinforced composites with an integrated system of wires made of shape memory alloys. A phenomenological model for the description of the material behavior of shape memory alloys is implemented in a commercial FE code. As the textile reinforcement shows periodically repeating patterns, the inner architecture of the composite can described by a representative volume element. Effective viscoelastic material parameters of the textile‐reinforced composite are determined with the help of homogenization techniques. For the application of the developed composite structure as a simple actuator, numerical results are compared with experimental data. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bainitic variant evolution in a low‐alloyed steel including numerical aspects
Authors: Ehlenbröker Ulrich , Mahnken Rolf 
Published: December 2014

AbstractBainite formation is of particular industrial relevance especially after hot‐forming and quenching of relatively bulky components. In these processes large portions of the component are subjected to appropriate cooling rates which yield a considerable fraction of the bainitic product phase. In our work, we develop a thermodynamically consistent multi‐scale model for phase transformations from austenite into 24 possible bainite variants. Furthermore, the model is capable to express the macroscopic effects of volume change due to phase transformation as well as to transformation‐induced plasticity (TRIP). Basic ideas for our material‐model can be found among others in [1–3]. Because of the highly complex, strongly coupled model equations, the numerical implementation is a very challenging task. Therefore, we make use of a projected Newton algorithm combined with an active‐set strategy, as an extension to the approach in [4] for austenite‐martensite transformations in shape memory alloys. Numerical examples illustrate the quadratic convergence behaviour in a Finite‐Element scheme. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Phase Field Approach for Martensitic Transformations and Crystal Plasticity
Authors: Schmitt Regina , Mayer Patrick , Kirsch Benjamin , Aurich Jan , Kuhn Charlotte , Müller Ralf , Bhattacharya Kaushik 
Published: December 2014

AbstractThis work is motivated by cryogenic turning which allows end shape machining and simultaneously attaining a hardened surface due to deformation induced martensitic transformations. To study the process on the microscale, a multivariant phase field model for martensitic transformations in conjunction with a crystal plastic material model is introduced. The evolution of microstructure is assumed to follow a time‐dependent Ginzburg‐Landau equation. To solve the field equations the finite element method is used. Time integration is performed with Euler backward schemes, on the global level for the evolution equation of the phase field, and on the element level for the crystal plastic material law. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phase‐field simulation of piezoresponse force microscopy in consideration of different environmental conditions
Authors: Thai Huy , Keip Marc‐André , Schröder Jörg 
Published: December 2014

AbstractPiezoresponse force microscopy (PFM) is a feasible tool which is widely used for investigating information of the domain structures of ferroelectrics. Nevertheless, one drawback of the technique may be that environmental conditions could effect the very small signal which is detected from the displacement of the tip. The present contribution addresses the simulation of PFM in consideration of environmental conditions. We employ a continuum‐mechanical model based on the phase‐field method which accounts for the transversely isotropic symmetry of the underlying material. The goal of this contribution is to analyze the environmental effect on the tip‐sample interaction. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of pre‐straining on the lifetime of filled elastomers
Authors: Krause Maria , Juhre Daniel 
Published: December 2014

AbstractPre‐conditioning is usually not considered in classical lifetime prediction analyses. The strong material softening observed in rubber materials, however, makes one expect a strong influence of the pre‐conditioning on the lifetime. For this contribution, experimental tests were carried out to verify and further investigate, how the pre‐loading affects the lifetime of filled natural rubber. Comparing the experimental results with according simulations using the MOdel of Rubber PHenomenology (MORPH) [1, 2] it is found that even though the simulation shows an extended lifetime with higher pre‐straining, the experimental data shows no significant influence of this pre‐conditioning. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A continuum mechanics approach for modelling arbitrary degradation and erosion processes in polymers
Authors: Seydewitz Robert , Bolea Albero Antonio , Böl Markus 
Published: December 2014

AbstractComposed of rather simple components some polymers show the ability to decompose from complex structures into substances that can be easily absorbed by the surrounding environment. The responsible processes behind chain shortening and eventually the material remove are degradation and erosion. The aim of this work is to model the chemo‐mechanical condition of the polymer material based on a discretised network model. Further, the influence of erosion processes on the morphology is investigated. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Molecular static simulations of ferroelectric material hysteresis behaviour
Authors: Endres Florian , Steinmann Paul 
Published: December 2014

AbstractThe present contribution deals with molecular static modelling and the simulation of ferroelectric material hysteresis behaviour. Therefore the core‐shell model is implemented in a molecular static algorithm. Moreover the algorithm is implemented as a finite element method for nonlinear trusses. Thereby the computational costs are reduced significantly compared to molecular dynamics. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Calculation of Stresses and Consistent Tangent Moduli from Automatic Differentiation of Hyerelastic Strain Energy Functions Through the Use of Hyper Dual Numbers
Authors: Tanaka Masato , Sasagawa Takashi , Omote Ryuji , Fujikawa Masaki , Balzani Daniel , Schröder Jörg 
Published: December 2014

AbstractMany materials as e.g. engineering rubbers, polymers and soft biological tissues are often described by hyperelastic strain energy functions. For their finite element implementation the stresses and consistent tangent moduli are required and obtained mainly in terms of the first and second derivative of the strain energy function. Depending on its mathematical complexity in particular for anisotropic media the analytic derivatives may be expensive to be calculated or implemented. Then numerical approaches may be a useful alternative reducing the development time. Often‐used classical finite difference schemes are however quite sensitive with respect to perturbation values and they result in a poor accuracy. The complex‐step derivative approximation does never suffer from round‐off errors, cf. [1], [2], but it can only provide first derivatives. A method which also provides higher order derivatives is based on hyper dual numbers [3]. This method is independent on the choice of perturbation values and does thus neither suffer from round‐off errors nor from approximation errors. Therefore, here we make use of hyper dual numbers and propose a numerical scheme for the calculation of stresses and tangent moduli which are almost identical to the analytic ones. Its uncomplicated implementation and accuracy is illustrated by some representative numerical examples. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Law for Small Scale, Continuous Calving
Authors: Christmann Julia , Müller Ralf , Humbert Angelika 
Published: December 2014

AbstractIce shelves are formed by the viscous flow of inland ice into the ocean, they are floating and loosing mass by iceberg calving. There are two different kinds of calving: large tabular icebergs detach as singular events in time, and small scale calving occuring on a rather continuous time scale. Three visco‐elastic approaches are discussed, in order to derive a general law for calving rates applicable to small scale calving. The results are highly dependent on the termination criterium for each approach, hence the computed calving rate has to be adapted and validated with measurements to get the most qualified value. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simulation of Autofrettage in Curvilinear Coordinates
Authors: Müller Wolfgang H. , Reich Felix A. 
Published: December 2014

AbstractPressure vessels subjected to high mechanical loadings can fail due to microscopic crack growth, i.e., stress corrosion cracking. A popular way to increase the crack resistance of a structure is by autofrettage. The standard approach to obtain a numerical solution for the involved fields is to discretize w.r.t. Cartesian coordinates as implemented in common commercial FE programs. However, this approach is computationally costly in comparison to pure elastic simulations—often rendering this method practically unfeasible. The current work shows that autofrettage can be simulated more efficiently in extensive bodies that can be described by a bijective map where certain symmetries are available in load and form. The discretization and the mathematical formalism of this approach in curvilinear coordinates are described. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)