bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modal Analysis of Vehicle Power Trains
Authors: Haslinger Josef , Offner Günter , Sopouch Martin , Zinkiewicz Bianka 
Published: October 2015

AbstractIn this study, modal analysis of vehicle power trains is based on the linearization of the underlying equations of motions at specified time instants. The equations of motion represent a flexible multi‐body system where force‐elements (joints) connect different bodies. Whenever the linearization leads to an ordinary differential equation with constant coefficients, a standard eigenvalue procedure is used, to compute eigenvalues and mode shapes. The concept is applied to a vehicle power train. Comparison of the results with a commercial software product provide good agreement. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Real‐Time Simulation of Elastic Multibody Systems with Application in Vehicle Dynamics
Authors: Schmitt Alexander , Seifried Robert 
Published: October 2015

AbstractReal‐time simulation models are widely used for vehicle development, usually built up as rigid multibody systems. However, since lightweight structures are commonly used, body deformation is no longer negligible and rigid multibody simulations may be inaccurate. This work presents a real‐time capable full vehicle model with a flexible car body, derived from a finite element model, whose performance has been improved by model order reduction. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Performance assessment of a trajectory‐tracking approach for a manipulator with uncertainties using inverse fuzzy arithmetic
Authors: Walz Nico‐Philipp , Hanss Michael 
Published: October 2015

AbstractA trajectory‐tracking approach for a parallel kinematic manipulator with flexible links is investigated with respect to its robustness to undesired initial oscillations. For this purpose, an inverse fuzzy arithmetical scheme is presented and applied, in order to estimate allowable bounds on the initial conditions such that a certain tolerance band around the desired trajectory is not violated. The uncertainty bounds on the initial conditions obtained from this identification procedure indicate the influence of the disturbances on the tracking error, and thus also the robustness and the performance of the control scheme. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A numerical method for the servo constraint problem of underactuated mechanical systems
Authors: Yang Yinping , Betsch Peter , Altmann Robert 
Published: October 2015

AbstractServo constraints are used in inverse dynamics simulations of discrete mechanical systems, especially for trajectory tracking control problems [1], whose desired outputs are represented by state variables and treated as servo constraints [2]. Servo constraint problems can be classified into fully actuated and underactuated multibody systems, and the equations of motion take the form of differential algebraic equations (DAEs) including holonomic and servo constraints. For fully actuated systems, control inputs can be solved from the equations by model inversion, as the input distribution matrix is nonsingular and invertible. However, underactuated systems have more degrees of freedom than control inputs. The input distribution matrix is not invertible, and in contrast to passive constraints, the realization of servo constraints with the use of control forces can range from orthogonal to tangential [3]. Therefore, it is challenging for the determination of control inputs which force the underactuated system to realize the partly specified motion. For differentially flat underactuated systems, the differentiation index of DAEs may exceed three. Hence we need to apply specific index reduction techniques, such as the projection approach applied in [3], [4], and [6]. The present work applies index reduction by minimal extension [5] to differentially flat underactuated crane systems and shows that the index can be reduced from five to three and even to one. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mechanics of cell‐division: A new continuum model for growth inhomogeneities
Authors: Bolea Albero Antonio , Böl Markus 
Published: October 2015

AbstractThe self‐reproduction ability of mitotic cells results in an increase of the number of cells with the same characteristics in living bodies. While cells grow in volume and divide themselves, the living body consequently grows in mass and volume. Further, if the factors which regulate the growth process are inhomogeneously distributed, growth takes place at different rates and directions. In this work we aim to provide a new continuum model for growing tissues. More specifically, the model considers the reorientation of the cell‐division plane in mitotic cells depending on the stress field of the growing body. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Computational simulation of piezo‐electrically stimulated bone remodeling surrounding teeth implant
Authors: Shirazi Beheshtiha Alireza , Nackenhorst Udo 
Published: October 2015

AbstractSince the natural ligament responsible for the fixation of teeth in jawbone is destroyed when artificial replacements are implanted, the mechanical stimulation of the bone is reversed. Idea of this research project is the development of active implants which provide additional electrical stimulation for bone adaption. A new electromechanically driven bone remodeling theory will be developed and the osseointegration of bone implants has been simulated by means of bio‐active interface theory. The thin bone‐implant interface is described by the Drucker‐Prager plasticity model. Besides the consistent combination of electromechanical bone remodeling simulation, 3D‐finite element model of lower mandible has been reconstructed. As the micromotions at the implant‐abutment level are reported to be a major determinant of longterm implant success, the osseointegration process is limited by micromotion threshold. The applicability is indicated on a dental implant in order to optimize new developed techniques for activating implants with piezo‐electric coatings. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Application of a cohesive zone element for the prediction of damage in nano/micro coating
Authors: Rezaei Shahed , Wulfinghoff Stephan , Kebriaei Reza , Reese Stefanie 
Published: October 2015

AbstractMany tools in production technology are nowadays coated to obtain a satisfactory lifetime and degradation resistance. Therefore, the main goal of this study is to investigate antiadhesive and wear resistant coatings made of ceramics, plastics and metals produced by High Power Pulsed Magnetron Sputtering (HPPMS) technique [1]. A cohesive zone element technique (CZ) is applied to model the interactions of the coatings and the substrate surfaces (see [2]). This goes along with the investigations of the delamination and failure behavior of the involved surfaces. To illustrate the applicability of the model, several structural simulations are performed. The developed CZ element model is capable of modeling the separation, the contact and also the irreversible reloading conditions in both normal and tangential directions [3]. The model is further developed to be applicable for different structures including different bonding behaviors, with a higher stability. The talk concludes with a detailed discussion of the numerical results of different material and interface properties. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fitting stress intensity factors from crack opening displacements in 2D and 3D XFEM
Authors: Schätzer Markus , Fries Thomas‐Peter 
Published: October 2015

AbstractThe computation of stress intensity factors (SIFs) by crack opening displacements (CODs) is discussed in linear elastic fracture mechanics (LEFM) with stressfree crack surfaces, in the context of the extended finite element method (XFEM) and a hybrid explicit‐implicit crack description. Herein, the approximated CODs are compared with the expected openings for a pure mode I, II and III. The analytical modes are evaluated in a reference coordinate system, which is aligned with the (curved) crack surface and extracted from the implicit level‐set functions. This approach allows without any significant modifications, an intuitive and efficient computation of SIFs in 2D and 3D even of curved cracks. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A novel treatment of crack boundary conditions in phase field models of fracture
Authors: Strobl Michael , Seelig Thomas 
Published: October 2015

AbstractIn the phase field approach for fracture an additional scalar field is introduced in order to describe the state of the material between intact and fully broken. So far, for the loading dependent degradation of stiffness (damage) either the volumetric‐deviatoric split of strain [1, 2] or the spectral decomposition [3, 4] is used. In contrast to such an isotropic degradation of stiffness, the fully broken state represents a crack with a particular orientation. Both aforementioned approaches do not take the crack orientation into account. This may lead to the violation of the crack boundary conditions. In order to satisfy these conditions the phase field approach is modified here by taking the orientation of the crack into account. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimization of two‐layered steel/aluminum hollow cylinders under combined load
Authors: Apatay Tunç , Mack Werner 
Published: October 2015

AbstractSubject of the investigation is a two‐layered tube under generalized plane strain subject to a combination of internal pressure and an elevated temperature at the inner surface. Criterion for the permissible stress is the yield criterion by von Mises, and the elastic limits are given as well as a way for a straightforward optimization procedure in respect of the weight of the device is shown. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Shrink fit with FGM‐hub subject to heating and rotation
Authors: Arslan Eray , Mack Werner 
Published: October 2015

AbstractSubject of the investigation is an elastically designed shrink fit with solid inclusion and functionally graded hub. It is shown that in case of radially decreasing density not only a saving of weight but also a considerably better performance at rotation may be achieved which predominates over a marginally worse evolution of the interface pressure with increasing temperature. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Frequency veering and mode degeneration of a rectangular disc
Authors: Brouet Francois , Twiefel Jens , Wallaschek Jörg 
Published: October 2015

AbstractIn typical applications as ultrasonic welding horns, the oscillators are designed to be driven in the longitudinal mode. Modal interactions occur at critical aspect ratios, resulting in a poor uniformity of the output surface and assessing the geometry as critical. In this contribution, a method is presented for a simple rectangular disc how to eliminate the modal interaction and decouple the longitudinal mode from other modes. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
T‐splines discretizations for large deformation contact problems
Authors: Dimitri Rossana , Zavarise Giorgio 
Published: October 2015

AbstractA T‐spline‐based isogeometric analysis is applied to frictional contact problems between deformable bodies in the context of large deformations. The continuum is discretized with cubic T‐splines and cubic NURBS (Non‐Uniform Rational B‐Splines) for comparison purposes. A Gauss‐point‐to‐surface (GPTS) formulation is combined with the penalty method to treat the normal and friction contact constraints in the discretized setting. It is demonstrated that the proposed formulation combined with analysis‐suitable T‐spline interpolations, is a computationally accurate and efficient technology for local and global solutions of contact problems. T‐spline analysis models are generated using commercially available T‐spline modeling software without intermediate mesh generation or geometry clean‐up steps. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Flexure Hinge Mechanisms Modeled by Nonlinear Euler‐Bernoulli‐Beams
Authors: Friedrich Robert , Lammering Rolf 
Published: October 2015

AbstractA flexure hinge is an innovative engineering solution for providing relative motion between two adjacent stiff members by the elastic deformation of an arbitrary shaped flexible connector. In the literature, modeling of compliant mechanisms incorporating flexure hinges is mainly focused on linear methods. However, geometrically nonlinear effects cannot be ignored generally. This study presents a nonlinear modeling technique for flexure hinges based on the Euler‐Bernoulli beam theory, in contrast to the predominant linear modeling approaches. Higher order beam elements of variable cross‐section are employed to model the flexure hinge region. A Newton‐Raphson scheme is applied to solve the resulting nonlinear system equations. The proposed approach reduces the overall degrees of freedom and is computationally efficient compared to commonly applied 3D finite element methods. A compliant displacement amplification mechanism is studied by means of the proposed method, where an excellent agreement with results of a reference solution is achieved. The modeling approach is suitable for the structural optimization of compliant mechanisms towards a less intuitive design process. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fluid pressure penetration for advanced FEA of metal‐to‐metal seals
Authors: Gorash Yevgen , Dempster William , Nicholls William D. , Hamilton Robert 
Published: October 2015

AbstractThis numerical study investigates the behaviour of the contact faces in the metal‐to‐metal seal of a typical pressure relief valve in the commercial FE‐package ANSYS. The valve geometry is simplified to an axisymmetric problem, which comprises a simple representative geometry consisting of only three components. A cylindrical nozzle, which has a valve seat on top, contacts with a disk, which is preloaded by a compressed linear spring. Analysis considerations include the effects of the Fluid Pressure Penetration (FPP) across the valve seat which exists at two different scales. In‐service observations show that there is certain limited fluid leakage through the valve seat at operational pressures about 90% of the set pressure, which is caused by the fluid penetrating into surface asperities at the microscale. At the macroscale, non‐linear FE‐analysis using the FPP technique available in ANSYS revealed that there is also a limited amount of fluid penetrating into gap, which is caused primarily by the global plastic deformation of the valve seat. Accurate prediction of the fluid pressure profile over the valve seat is addressed in this study by considering the FPP interaction on both scales. The shape of this pressure profile introduces an additional component of the spring force, which needs to be considered to provide a reliable sealing. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Evaluation of a Finite Element Approach for Damping Determination
Authors: Hentschel Olaf Peter , Bonhage Marius , Panning‐von Scheidt Lars , Wallaschek Jörg 
Published: October 2015

AbstractIn this paper, a well‐known law for material damping description (see [1]) is verified. Thereby, material damping is characterized as a function of local stress amplitudes. To identify the resulting structural damping, a calculation of local stresses is necessary. In a first step, an analytical approach is used to calculate the damping on the basis of the stress distribution. In a second step, the local stress distribution of the described structure is calculated using a finite element approach. In this context, damping is calculated using the identified discrete stress values through the structure. By varying the mesh density, the resulting damping is compared to the calculated damping using the analytical results. Finally, it can be seen that the quality of the calculated damping value depends on the quality of the calculated stress value and therefore on the mesh density. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental investigations on PP‐PE foil specimens
Authors: Sguazzo Carmen , Hartmann Stefan 
Published: October 2015

AbstractIn the present work, we present an experimental characterization of a thermoplastic copolymer made out of Polypropylene and Polyethylene (PP‐PE); a polymer that is, for example, used as a core material for layered sandwich composites. The rate‐dependence and the temperature‐dependence were investigated by means of tensile tests within the large deformation range and by shear tests. The experiments were monitored using a Digital Image Correlation (DIC) system. The main goal of the experimental campaign is related to the development of a constitutive model. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Predicting delamination in multilayered CFRP laminates accounting for different failure modes
Authors: Simon Jaan‐Willem , Höwer Daniel , Reese Stefanie 
Published: October 2015

AbstractCarbon fiber reinforced plastics (CFRP) are mostly used in multilayered laminates, which consist of several very thin layers stacked over each other. For such laminated structures, delamination represents one of the most critical states of failure. In order to predict both the onset as well as the propagation of delamination, a cohesive zone‐like continuum damage model is proposed in this paper. This damage model is directly incorporated into a solid‐shell finite element with finite thickness. Further, the formulation is capable of considering the interaction of different failure modes. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the influence of vibrations on macroscopic frictional contacts
Authors: Hammerschmidt Antonia , von Wagner Utz 
Published: October 2015

AbstractUltrasonic vibrations in the micrometer amplitude range have been proven to be capable to influence frictional contacts with respect to decreasing friction coefficients in experiments on small test set‐ups solely loaded by their small weight [1]. In this paper experimental results on applying this effect to large objects are presented. To get large vibration amplitudes and velocities detailed pre‐investigation on the excitation of the structures in contact have been performed. These structures are investigated in a roller rig designed for these purposes. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the Effect of Contact Compliance on Vibrational Smoothing of Dry Friction
Authors: Kapelke Simon , Seemann Wolfgang 
Published: October 2015

AbstractHigh‐frequency vibrations may be utilized in order to smooth the characteristics of dry friction at low sliding velocities and, consequently, quench undesired friction induced phenomena. Many studies have been published so far, most of them using classical Coulomb friction models and yielding compact results. Unfortunately, the agreement with related experimental results is insufficient. As the Coulomb model overestimates the smoothing effect, improved modelling seems to be necessary. Based on Dahl's friction model, the effect of longitudinal and transverse high‐frequency vibrations on a 1‐DoF‐friction oscillator is investigated here. Accounting for contact compliance, a reduction of the smoothing effect is observed. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synchronization effects in rotors partly filled with fluid
Authors: Keisenberg Tobias , Ostermeyer Georg‐Peter 
Published: October 2015

AbstractIn fluid‐filled rotors self‐excited vibrations occur induced by a surface wave of the fluid. A characteristic property is the instability over the full range of angular velocity above the Eigenfrequency of the system. A possible explanation is the occurrence of synchronization effects between fluid and rotor.The behaviour of rotors partly filled with fluid was mostly studied under the aspect of stability in steady‐state conditions. For non‐steady‐state investigations, discrete models with reduced number of degrees of freedom and reasonable ability to model the system behaviour are desirable due to the complexity of fluid modelling.This paper analyses a simple minimal model and shows synchronization effects between fluid and rotor model. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ductile failure with gradient plasticity coupled to the phase‐field fracture at finite strains
Authors: Aldakheel Fadi , Raina Arun , Miehe Christian 
Published: October 2015

AbstractMost metals fail in a ductile fashion, i.e, fracture is preceded by significant plastic deformation. The modeling of failure in ductile metals must account for complex phenomena at micro‐scale, such as nucleation, growth and coalescence of micro‐voids. In this work, we start with von‐Mises plasticity model without considering void generation. The modeling of macroscopic cracks can be achieved in a convenient way by the continuum phase field approaches to fracture, which are based on the regularization of sharp crack discontinuities [1]. This avoids the use of complex discretization methods for crack discontinuities and can account for complex crack patterns. The key aspect of this work is the extension of the energetic and the stress‐based phase field driving force function in brittle fracture to account for a coupled elasto‐plastic response in line with our recent work [3]. We develop a new theoretical and computational framework for the phase field modeling of ductile fracture in elastic‐plastic solids. To account for large strains, the constitutive model is constructed in the logarithmic strain space, which simplify the model equations and results in a formulation similar to small strains. We demonstrate the modeling capabilities and algorithmic performance of the proposed formulation by representative simulations of ductile failure mechanisms in metals. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the variational formulation and implementation of Allen‐Cahn and Cahn‐Hilliard‐type phase field theories
Authors: Bartels Alexander , Mosler Jörn 
Published: October 2015

AbstractPhase field theory is a promising framework for analyzing evolving microstructures in materials. Phenomena like those related to microstructures in Ni‐based superalloys, twin structures in martensites or precipitation in Al‐alloys can be predicted by phase field theory. While phase transformations such as those characterizing twinning are captured by an Allen‐Cahn‐type approach, a Cahn‐Hilliard‐type formulation is used, if the respective interface motion is driven by the concentration of the species. Although the Allen‐Cahn and the Cahn‐Hilliard formulation are indeed different, they do share some similarities. To be more precise, a Cahn‐Hilliard model is obtained by enforcing balance of mass in the Allen‐Cahn approach. Within an energy‐based formulation this can be implemented by adding additional energy terms to the underlying Allen‐Cahn energy. Such a universal energy‐based framework is elaborated in this presentation. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Micro‐macro modelling of fiber reinforced composites exhibiting elastoplastic deformation
Authors: Bedzra Rex , Simon Jaan‐W. , Stier Bertram , Reese Stefanie 
Published: October 2015

AbstractFiber reinforced plastics such as carbon fiber‐reinforced composites are typically characterized by their high siffness to weight ratio making them particularly attractive in lightweight construction. In addition, the architecture of these materials means that the correct modelling of their orthotropy is very important. In this work, volume averaged stress‐strain responses are generated from a micro representative volume element (RVE). A nonlinear macro constitutive material model accounting for anisotropic plasticity is proposed. The model is fitted and compared to the micro stress‐strain response. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)