bluuebunny/crossref_metadata_2025_split huggingface dataset:
On Some Analytic Methods for Calculating of Cusped Prismatic Shells
Authors: Chinchaladze Natalia 
Published: December 2014

AbstractCusped plates, on the one hand, are very important details from the practical point of view, such plates and beams are often encountered in spatial structures with partly fixed edges, e.g., stadium ceilings, aircraft wings, submarine wings etc., in machine‐tool design, as in cutting‐machines, planning‐machines, in astronautics, turbines, and in many other areas of engineering (e.g., dams); on the other hand, their theoretical analysis and calculation are mathematically connected with the study of the problems for degenerate partial differential equations which are not covered by the general theory for degenerate partial differential equations (see, e.g., [3]). Some satisfactory results are achieved in this direction in the case of Lipschitz domains but in the case of non‐Lipschitz domains there are a lot of open problems. To investigate such problems are the main part of the the present paper. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determination of the Transverse Shear Stress in an Euler‐Bernoulli Beam Using Non‐Admissible Virtual Displacements
Authors: Eugster Simon , Glocker Christoph 
Published: December 2014

AbstractThe point of view that a beam can be considered as a three‐dimensional continuum with a constrained position field (cf. [1]) together with the virtual work principle and the concept of perfect constraint stresses, leads to a systematic way to reduce the equilibrium equations of the continuous body to an ordinary differential equation describing the constrained displacement field of the beam. Using virtual displacements, being non‐admissible with respect to the constrained beam kinematics, together with the solution of the boundary value problem, allows us to analytically determine the constraint stresses and consequently the total stresses of a beam up to a certain indeterminacy. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Kinematic modeling of flexure hinges and compliant mechanisms
Authors: Roesner Malte , Lammering Rolf 
Published: December 2014

AbstractIn this paper, the kinematic performance of flexure hinges and compliant mechanisms calculated by conventional modeling techniques are compared. As these exhibit certain drawbacks with regard to control strategies, mainly large number of degrees of freedom or unacceptable errors, a novel modeling approach for flexure hinges is presented. Instead of the entire flexure hinge only its significant regions are modeled by 3‐D structural solids. These master patterns are positioned appropriately and connected by rigid constraint conditions to build a compliant mechanism. The resulting model is characterized by considerably fewer degrees of freedom than a full solid model as well as a marginal deviation of the deflection compared to that of pseudo‐rigid‐body models, 3‐D tapered finite beam elements and analytical Timoshenko beam theory. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bending behavior of a bi‐morph piezoelectric curved beam
Authors: Usta Raif , Arslan Eray 
Published: December 2014

AbstractA simple and concise mathematical model describing the deformation and the electrical behavior of a bi‐morph piezoelectric curved sensor subjected to pure bending is developed. In particular, the influence of the couple moment on the electrical potential generated in the sensor is investigated and the results are presented in graphical form. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of measured and calculated eigenmodes for squirrel cage rotors using methods of design of experiments
Authors: Großhauser Johannes 
Published: December 2014

AbstractTo compare measured and calculated mode shapes, the natural frequencies and the mode shapes must be checked. For sensitivity analysis, which is the first step when optimizing parameters, the results must be automatically evaluated. When evaluating mode shapes and dependent natural frequencies, numerical values have to be determined. In this paper, a method is shown, how mode shapes and natural frequencies can be considered within one value for each mode shape. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Displacement‐based finite difference approximations of derivatives of the tangent stiffness matrix with respect to the load parameter
Authors: Jia Xin , Mang Herbert A. 
Published: December 2014

AbstractThe vehicle to investigate to which extent energy‐based categorization of buckling can be linked up with spherical geometry is the so‐called consistently linearized eigenproblem. This investigation requires computation of the first and the second derivative of the tangent stiffness matrix
$\tilde{\bf{K}}_T$
with respect to a dimensionless load parameter λ in the frame of the Finite Element Method (FEM). A finite‐difference approximation of the first derivative of
$\tilde{\bf{K}}_T$
, redefined as a directional derivative, has proved to meet the requirements of computational efficiency and sufficient accuracy. It represents a displacement‐based finite‐difference approximation, abbreviated as DBFDA. The present work is devoted to the computation of a DBFDA of the second derivative of ˜ KT with respect to λ. For the special case of a two‐dimensional co‐rotational beam element, an analytical solution of this derivative is presented. A circular arch, subjected to a vertical point load on its apex, serves as an example for numerically assessing the usefulness of the computed DBFDAs of the first and the second derivative of
$\tilde{\bf{K}}_T$
with respect to λ. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the non‐ideal vibrating structures
Authors: Chiroiu Veturia , Donescu Stefania , Dumitriu Dan 
Published: December 2014

AbstractIn this work, analysis of the response to vibrations of a small building equipped with an electromechanical vibration absorber is investigated. The case of harmonic excitation with constant or time dependent frequencies is considered. The interaction between the structure and the energy source is analyzed via the Sommerfeld effect inside the resonance region. The resonance capture and the vibration reduction are displayed by the time history displacement of the last story. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimum Tuned Mass Dampers for Structures at Rock and Soil Sites
Authors: Nigdeli Sinan Melih , Bekdas Gebrail 
Published: December 2014

AbstractIn optimum design of tuned mass dampers (TMD), several factors are effective. One of the most important factors is the characteristics of the excitation. Earthquake excitations recorded at soil and rock sites show different characteristics in period and damping. In this paper, optimum TMD properties are separately searched for seismic structures at soil sites and rock sites. For each optimization, six different earthquake records were used. A design methodology was used by employing harmony search (HS). The approach was applied to a ten story structure with one second critical period. Although more damping ratio for TMD is needed for soil sites than rock sites, TMD is more effective for rock sites than soil sites. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An energy‐entropy‐consistent time stepping scheme for finite thermo‐viscoelasticity
Authors: Krüger Melanie , Groß Michael , Betsch Peter 
Published: December 2014

AbstractThis paper presents a time integrator, which is based on a time discrete spatially weak finite element formulation, but fulfills the same balance laws as the underlying (five) differential equations. Namely, in addition to the balances of linear and angular momentum as well as entropy, also the balances of total energy and LYAPUNOV function are fulfilled. The spatially weak formulation is obtained by integration by parts. Where the resulting virtual stress power term is well‐known, the virtual entropy production by conduction of heat is less known. The time discretisation is based on the midpoint rule and non‐standard time discrete differential operators. This time integrator is a further development of the TC integrator of I. ROMERO. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Enhanced low‐order displacement finite elements using incompatible mass scaling and static condensation in explicit time integration
Authors: Schmied Christoph , Mattern Steffen , Schweizerhof Karl 
Published: December 2014

AbstractFor nonlinear transient problems as well as rather slow quasi‐static processes explicit time integration has proven to be a suitable and robust time integration algorithm. As a consequence of the Courant‐Friedrichs‐Lewy (CFL) criterion small time step sizes are necessary and the overall computation time is dominated by the operations on element level. Privileged use of low order finite elements is common in explicit time integration due to their efficiency and robustness. In order to suppress artificial locking effects the work of Bischoff and Romero [1] is followed where a generalization of the method of incompatible modes (IM) is derived being equivalent to the class of enhanced assumed strain (EAS) elements originally proposed by Simo and Rifai [2]. These concepts are bound to a static elimination procedure of internal parameters which may result in a considerable expansion of the computational costs in the case of an explicit time integration scheme. In order to avoid the static elimination procedure inertia is considered for the incompatible parameters as suggested by Mattern et al. [3, 4]. This step allows integrating the incompatible parameters directly in time, but since rather large stiffnesses are related to the incompatible parameters – particularly for the volumetric mode enhancements – the highest eigenfrequency may be increased which would lead to a decrease of the time step size. This motivates scaling the masses associated to these incompatible parameters to control their effect on the time step size. It is possible to derive analytically based estimates for the scaling of the IM‐masses in order to achieve results agreeing very good with the classical EAS approach including large deflections and nonlinear material behaviour with elasto‐plasticity. The numerical implementation is performed using AceGen [5]. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Assessment of the static and fatigue strength of a precession driven dynamo under thermomechanical loads
Authors: Beisitzer Stephan , Scheffler Michael , Beitelschmidt Michael 
Published: December 2014

AbstractAt the Helmholtz‐Zentrum Dresden‐Rossendorf an experimental plant is developed to investigate the formation of magnetic fields in flows of liquid metals. Because of the enormous hazard potential of the used liquid sodium it is essential to avoid any damages during operation and so a detailed analysis using the finite element method is necessary considering the various mechanical and thermal loads. Therefore several tens of thousands load cases have to be taken into account. Hence an algorithm is developed to identify the relevant stresses referring to FKM guideline which are used for the static and fatigue strength assessment. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A two‐scale simulation method accounting for thermal effects during turning
Authors: Schindler Stefan , Zimmermann Marco , Aurich Jan C. , Steinmann Paul 
Published: December 2014

AbstractDuring chip formation in turning processes, mechanical work is dissipated into thermal energy by plastic deformations and frictional processes. In case of dry cutting, the generated heat is in part removed with the chips while the rest flows into the tool and the workpiece. Within the latter, the temperature increases due to this heat flow, which in turn causes thermal expansions that increase the cutting depth and thus induce deviations from the nominal workpiece geometry. These effects are treated separately by a local model for the chip formation and a global model for the whole workpiece in order to determine the temperature distribution inside the workpiece and the dependent thermal expansion. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling of packaging behavior in closed‐cell aluminum foam
Authors: Ievdokymov Mykola , Eremeyev Victor A. , Altenbach Holm 
Published: December 2014

AbstractThe aim of this paper is to present the available modeling strategy available for description of the packaging behavior, which often takes place in the foams. The packaging process is modeled by means of approaches, which are used in the phase transformation theory. The constitutive model is based on the double‐well elastic potential, which is defined for small strains. Two principal approaches are used for the research: discrete method based on the Voronoi tessellation and phase‐field method. Discrete modeling approach is required for the estimations of the critical stresses in foams, which leads to the initiation of the packaging process. The phase‐field approach is the continual approach, which is required for description of the packaging propagation in the foam. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On a least‐squares formulation for hyperelastic, transversely isotropic problems
Authors: Steeger Karl , Schwarz Alexander , Schröder Jörg , Starke Gerhard , Müller Benjamin 
Published: December 2014

AbstractIn the present work a mixed finite element based on a least‐squares formulation is proposed. In detail, the provided constitutive relation is based on a hyperelastic free energy including terms describing a transversely isotropic material behavior. Basis for the element formulation is a weak form resulting from a least‐squares method, see e.g. [1]. The L2‐norm minimization of the residuals of the given first‐order system of differential equations leads to a functional depending on displacements and stresses. The interpolation of the unknowns is executed using different approximation spaces for the stresses (Wq (div, Ω)) and the displacements (W1,p(Ω)), under consideration of suitable p and q. For the approximation of the stresses vector‐valued shape functions of Raviart‐Thomas type, related to the edges of the respective triangular element, are applied. Standard interpolation polynomials are used for the continuous approximation of the displacements. The performance of the proposed formulation will be investigated considering a numerical example. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling and Simulation of Asphalt
Authors: Wimmer Johannes , Schnepp Johannes , Reese Stefanie 
Published: December 2014

AbstractIncreasing requirements on the durability of road pavements demand the conception of innovative asphalt types. Particularly the stability under load needs improvement in order to prevent rutting. Since the load bearing capabilities of asphalt are mainly governed by the granular lattice and the binder that glues the rocks together, simulation based approaches that aim on supporting R&D in road engineering must capture the granulometry of the material. A Voronoi tesselation based description of the structure is proposed that enables the separate modelling of grains and binder as continuous materials and attempts to accurately reproduce those features. First, a neat Voronoi tesselation is created within the modelling domain. These irregular convex polyhedra representing the grains are subsequently subject to a shrinking process and further modified to accurately represent the granulometric distribution of real asphalt types. Now, the space between the grains can be used for a volumetric representation of the binder. Full‐field strain measurements during the indirect tensile test of mastic asphalt, stone mastic asphalt and asphalt concrete have been performed for validation of the approach. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Efficient computation of cellular materials using the finite cell method
Authors: Heinze Stephan , Joulaian Meysam , Egger Herbert , Düster Alexander 
Published: December 2014

AbstractThe application of cellular materials in lightweight structures is a subject of growing interest. As meshing with surface aligned elements is very time consuming and entails a lot of degrees of freedom, we apply the finite cell method (FCM). The FCM is an extension of the known fictitious domain methods based on using high order polynomials for the Ansatz functions. In order to obtain a realistic representation of the geometry, we derive our discretization directly from the voxel data coming from the computer tomography (CT‐scan) of the specimen of interest. Thus, a much coarser Cartesian grid consisting of hexahedral cells can be readily generated in a fully automated fashion. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
FEM‐Simulation of “Die‐Less Hydroforming”
Authors: Metzger Andreas , Ruff Daniel C. , Ummenhofer Thomas 
Published: December 2014

AbstractThe following contribution focuses on the FEM‐simulation of “Die‐Less‐Hydroforming” using LS‐DYNA. That specific forming technology is used to create structures by inflating initial seal‐welded flat 2D blanks as well as 3D hollow bodies without using any die, mould or punch in contrast to conventional hydroforming (e.g. tube hydroforming or hydromechanical deep drawing). (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Advanced Solution Strategies for r‐Adaptive Finite Element Analysis
Authors: Rambausek Matthias 
Published: December 2014

AbstractIn Finite Element Analysis (FEA) the discretisation has wide influence on the quality of the analysis. With r‐adaptive FEA it is aimed to improve the finite element solution by finding the optimal mesh without changing the mesh connectivity and the order of the elements. Thus, this approach belongs to the group of mesh‐moving methods. The r‐adaptivity approach presented is governed by energy minimisation and therefore is called energy‐based. It is built upon a variational Arbitrary Lagrangian‐Eulerian (vALE) formulation whereby the potential energy is varied with respect to spatial and material coordinates. However, even for simple problems the Hessian is likely to be singular or indefinite. This complicates the application of solution schemes based on Newton's method. Motivated by the approaches of [1–4], we try to find appropriate numeric methods for r‐adaptivity. For this purpose, we study the numerical performance of a primal barrier scheme, of an augmented Lagrange barrier scheme and the primal‐dual interior point package IPOPT. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The anisotropic coupling of one‐dimensional problems in linear elasticity
Authors: Schneider Patrick , Kienzler Reinhold 
Published: December 2014

AbstractWe investigate the coupling of the four one‐dimensional problems of linear elasticity (i.e., the rod‐, the two beam‐ and the shaft‐problem), for the case of a cross section that has two orthogonal axes of reflectional symmetry. An analytical proof is given, that the problems are decoupled for a homogeneous orthotropic material and the coupling behavior is given for monoclinic materials in dependence of the orientation of the symmetry plane. For a general anisotropic (aelotropic) material all four problems are coupled. We also identify the driving forces for the four problems, leading to a detailed definition of the admissible load‐cases for the classical problems, so that any three‐dimensional load‐case can be uniquely decomposed into the driving forces of the four problems. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Weak coupling of thin‐walled multi‐patch NURBS structures in the framework of isogeometric analysis
Authors: Ruess Martin , Guo Yujie 
Published: December 2014

AbstractIn the framework of isogeometric analysis, models are typically derived by the use of computer‐aided geometric design (CAGD) tools which often results in a large number of non‐conforming NURBS patches that are connected along arbitrary curved boundaries. A strong coupling on the basis of matching control meshes is rarely possible and limits the modeling process for practical applications. Weak coupling according to the principles introduced by Nitsche is the method of choice if a stable and variationally consistent method is favored which does not require the solution of additional equations to enforce the coupling constraints. We concentrate on the weak coupling of thin‐walled shell structures modeled according to the theory of Kirchhoff‐Love. The proposed concept is free of ad‐hoc decisions for stabilization thus truly supporting a design‐through‐analysis idea. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Uncertainty and Sensitivity Analysis of Different Models of Brake Squeal
Authors: Hanselowski Andreas , Hanss Michael 
Published: December 2014

AbstractIn this contribution, the brake‐squeal phenomenon is investigated using the pin‐on‐disc setup. The setup is analyzed numerically using the finite element method. The finite element model is evaluated in the time domain, and the vibration mechanism leading to squeal as well as the limit cycles of the vibration are analyzed. Against the background of the high computational costs, it is evaluated to what extent the Hoffmann‐Gaul minimal model can reproduce the results of the finite element model. Moreover, as brake squeal is very sensitive with respect to parametric uncertainties, the influence of several parametric uncertainties on the limit cycles is analyzed. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the Influence of High‐Frequency Excitation on Systems with Dynamic Friction
Authors: Kapelke Simon , Hetzler Hartmut , Seemann Wolfgang 
Published: December 2014

AbstractBy imposing high‐frequency vibrations to a system, the characteristics of dry friction for low sliding velocities can be smoothed and, consequently, undesired friction induced phenomena such as stick‐slip motion can be quenched. Many studies have been published so far, most of them focussing on the reduction of friction between metal surfaces and using classical Coulomb friction models. Within this contribution the effect of high‐frequency excitation on dry friction taking into account dynamic friction models will be discussed. To this end, the friction law suggested by Dahl is used and the resulting friction characteristics are compared to those obtained for the classical Coulomb friction model. Using Dahl's friction model, a reduction of the smoothing effect is observed. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the influence of boundary conditions on the modal properties of a base frame
Authors: Renning Maik , Kracht Kerstin , von Wagner Utz , Köster Philipp , Bozkurt Taner 
Published: December 2014

AbstractSupports of turbomachineries can be designed as base frames, which are constructions of steel‐plates. One of the most important design requirements of the turbomachinery system is to avoid of natural frequencies in the operating speed range. Thus, a rotor dynamics analysis (see e.g. [1]), which is usually carried out using transfer matrix methods or finite element methods has to take the dynamic stiffness of the base frame into account. However, there are several problems to identify this complex and frequency dependent parameter, for example the localization of excitation or measurement responses and the difficulty of the support of base frames, e.g jack screws.In this article the support of a test base frames is analyzed by modal analysis experimentally. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Time‐efficient analysis of nonlinear dynamic behavior
Authors: Sprock Christian , Sextro Walter 
Published: December 2014

AbstractMany nonlinear mechanical oscillators show excitation‐dependent behavior. In this paper, a new measurement approach is presented to analyze such structures. The main advantage of the presented method is the high efficiency, since measurement duration and loads to the structure are significantly reduced. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)