bluuebunny/crossref_metadata_2025_split huggingface dataset:
On modelling and analysis of gear drives with nonlinear couplings
Authors: Byrtus Miroslav , Zeman Vladimír 
Published: January 2007

AbstractThe paper deals with modelling of vibration of shaft systems with gears and rolling‐element bearings using the modal synthesis method with DOF number reduction. The influence of the nonlinear bearing and gearing contact forces with the possibility of the contact interruption is respected. The gear drive nonlinear vibrations caused by internal excitation generated in gear meshing, accompanied by impact and chaotic motions are studied. The theory is applied to a simple test‐gearbox. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bi‐harmonically excited pendulum: shifted resonances and quenching the low frequency excitation
Authors: Fidlin A. 
Published: January 2007

AbstractThe effect of the harmonic high‐frequency vibration of the suspension point on a mathematical pendulum is well known [1]. It can be described as stiffening/softening or stabilization/destabilization of the up‐pointing and down‐pointing equilibriums for pure vertical or pure horizontal excitation. If the excitation is tilted the effect of biasing appears in addition [2]. The effects of bi‐harmonic excitation are more complex. Two of them are discussed in the recent paper. The first one occurs if one of the excitation frequencies is high and another one is low. Then the so called shifted or conjugated resonances can be observed [3]. The second one takes place if the two excitation frequencies are high but their difference is small (slowly modulated high‐frequency excitation according to [4]). It is shown that in that case it is possible to choose the bi‐harmonic excitation in order to quench the resonance of the pendulum without changing its basic frequency. The analysis is fulfilled both for the external and parametric excitations. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Neufassung und Anwendung einer nichtlinearen Seiltheorie
Authors: Heinen Anton , Thalheim Jens‐Uwe 
Published: January 2007

AbstractVorgestellt wird eine neugefasste, geometrisch nichtlineare Seiltheorie (siehe auch [1]), die der klassischen Theorie [2] mechanisch gleichwertig ist, aber einfachere Nichtlinearitäten aufweist und daher numerische Vorteile bietet. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vibrations of linear structures with spatial local nonlinearities
Authors: Heuer Rudolf 
Published: January 2007

AbstractClassical Modal Analysis can be applied to linear systems if the corresponding damping matrix is proportional to the mass or/and stiffness matrices. Otherwise, e.g., in case of structures with single external damping devices, an alternative or approximate solution procedure for determining the dynamic response has to be chosen, compare [1]–[3]. Vibration problems of linear structures with spatially localized nonlinearities are related to those non‐classically damped systems. Such systems are characterized by the fact that their nonlinear behavior is largely restricted to a limited number of single points in the structure. The objective of this paper is to present an approximate semi‐analytical procedure for analyzing the steady‐state harmonic response of those locally nonlinear structures, where special emphasis is laid on beams with single nonlinear devices. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bifurcation Behavior of a 1DOF Sliding Friction Oscillator
Authors: Schwarzer Daniel , Hetzler Hartmut , Seemann Wolfgang 
Published: January 2007

AbstractThis article deals with different types of friction models and their influence on the behavior of a simple 1 degree‐of‐freedom (DOF) sliding friction oscillator which is in literature commonly referred to as “mass‐on‐a‐belt”‐oscillator. The examined friction characteristics are assumed to be proportional to the applied normal force and only dependend on the relative velocity between the mass and the belt. For an exponential and a generalized cubic friction characteristic, the linear stability of the steady‐state and the bifurcation behavior in the sliding domain are examined. It is shown that the resulting phase plots of the observed system are strongly dependent on the chosen friction characteristic. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamics of an Euler Elastica Pipe with Internal Flow of Fluid
Authors: Stangl Michael , Irschik Hans 
Published: January 2007

AbstractThe equations of motion for a cantilever Euler elastica pipe are deduced applying a generalized set of Lagrange equations for non‐material volumes. Based on an exact planar nonlinear beam theory the strain energy for the pipe is derived. The classical Lagrange terms and the additional terms due to moving mass entering and exiting the system result in a set of nonlinear equations of motion for the cantilever pipe with internal flow. A possible dimensional reduction and comparison to existing works are performed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bifurcations of Stick‐Slip‐Separation Waves in a Brake‐like System
Authors: Steindl Alois 
Published: January 2007

AbstractWe consider a system composed of an elastic tube in frictional contact with a rotating rigid cylinder. At the contact surface several types of rotating slip‐stick and also slip‐stick‐separation waves with different wave numbers can be observed. In order to determine the stability of these travelling waves, we have to solve a non‐local eigenvalue problem. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Maximum friction law in plasticity
Authors: Alexandrov Sergei 
Published: January 2007

AbstractThe maximum friction law postulates that the friction stress is equal to the maximum possible shear stress admissible by the constitutive equations. The boundary value problems including the maximum friction stress as a boundary condition reveal special mathematical features which are of interest in the development of theories and models, numerical simulation and engineering applications. The present paper shortly reviews the singularity in velocity fields that can occur in the vicinity of maximum friction surfaces. A large class of rigid plastic (in a broad sense that the elastic portion of the strain rate tensor is neglected) is considered. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Identifikation von Materialparametern anhand inhomogener Versuche
Authors: Besdo D. , Hohl C. , Ihlemann J. 
Published: January 2007

AbstractFür die Anwendung von Stoffgesetzen benötigt man einen sicheren Weg, um die im Stoffgesetz enthaltenen Parameter zu bestimmen. Dazu werden Messungen des entsprechenden Materials benötigt, die sicher und reproduzierbar durchgeführt werden können. Dabei kann es von Vorteil sein, nicht nur die üblichen homogenen Messmethoden zu verwenden, sondern diese Beschränkung für Versuche aufzugeben, die dafür klare Randbedingungen aufweisen und einfach zu messen sind. Es wird eine Methode aufgezeigt, mit der auch für solche Versuche Parameter identifiziert werden können, indem die kommerzielle FEM‐Software ABAQUS zur Simulation der (inhomogenen) Versuche benutzt wird. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Boundary element method for dynamic inelastic analysis
Authors: Czyż Tomasz , Fedelinski Piotr 
Published: January 2007

AbstractThe paper shows formulation and application of the boundary element method (BEM) for dynamic analysis of elastoplastic materials. The initial stress approach is used in the elastoplastic analysis. The mass matrices are computed by the dual reciprocity method (DRBEM). Displacements and stresses are computed by the iterative procedure in each time step. The time dependent problem is solved by the direct integration Houbolt method. The methods presented in the paper are applied to compute displacements and stresses in a crank loaded by dynamic forces. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An Approach to the Modeling of Physical Ageing in Rubbery Polymers
Authors: Dal Hüsnü , Kaliske Michael 
Published: January 2007

AbstractThe oxidation reactions responsible for physical ageing are thermally activated processes and yield cross‐linking similar to the vulcanization process and chain‐scission reactions. Chain scission, is responsible for the relaxation behaviour under constant stretch, whereas cross‐linking is responsible for hardening of the material. The decrease in the stretch at break upon cross‐linking motivates the so called network alteration proposed in this contribution. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A generalized polyconvex hyperelastic model for anisotropic solids
Authors: Ehret Alexander E. , Itskov Mikhail 
Published: January 2007

AbstractA generalized polyconvex hyperelastic model for anisotropic solids is presented. The strain energy function is formulated in terms of convex functions of generalized invariants and is given by a series with an arbitrary number of terms. The model addresses solids with orthotropic or transversely isotropic material symmetry as well as fiber‐reinforced materials. Special cases of the strain energy function suitable for anisotropic elastomers and soft biological tissues are proposed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Non‐local modeling of thermomechanical localization in metals
Authors: Flatten Arnd , Klingbeil Dietmar , Svendsen Bob 
Published: January 2007

AbstractThe purpose of this work is to compare and contrast two different modeling approaches for high‐speed, dynamic loading of metals. A so‐called “local” model including hardening, strain‐rate hardening as well as temperature and ductile damage softening behaviour is extended by gradient plasticity. In particular, both models are compared in the context of their application to the modeling and simulation of dynamic shear‐banding in the alloy Inconel 718. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multidimensional Tests of Superelastic, Polycristalline NiTi under Isothermal Conditions
Authors: Grabe Christian , Bruhns Otto T. 
Published: January 2007

AbstractDifferent isothermal and non‐isothermal tension/torsion tests are conducted on hourglass‐shaped, superelastic NiTi specimens. A new measurement device based on inductive displacement transducers is presented allowing for a directly decoupled measurement of twist and elongation at the same measuring points within the gage length. Thus, not only measuring but also controlling the deformation of the specimen is possible. The specimen temperature is actively controlled to keep the temperature deviation as low as possible and to be able to react immediately to sudden changes in the temperature field due to latent heat generation/absorption during phase transitions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modellierung und Simulation thermomechanischer Kopplungsphänomene
Authors: Helm Dirk 
Published: January 2007

AbstractMetallischeWerkstoffe zeigen insbesondere bei großen Deformationen und hohen Deformationsgeschwindigkeiten stark ausgeprägte thermomechanische Kopplungsphänomene. Zur Beschreibung dieser Kopplungsphänomene wird ein Materialmodell der finiten Thermoviskoplastizität vorgestellt. In dem Modell wird die Annahme verwendet, dass die viskoplastischen Deformationen isochor sind. Das entwickelte Modell ist in der Lage, die wesentlichen experimentellen Beobachtungen zu beschreiben. Zur numerischen Lösung thermomechanisch gekoppelter Anfangs–Randwertaufgaben wird die Methode der finiten Elemente verwendet. Die hierbei erforderliche numerische Integration der Konstitutivgleichungen erfolgt unter Verwendung eines in [5] entwickelten Integrationsoperators: Dieser Integrationsoperator besitzt die Eigenschaft, dass die Unimodularität der Integrationsvariablen für beliebige Zeitinkremente erhalten bleibt. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Adaptivity in the context of high speed cutting
Authors: Hortig Christian , Svendsen Bob 
Published: January 2007

AbstractThe purpose of this short work is the thermomechanical modeling of shear band and chip formation during high‐speed cutting. Shear bands develop in areas of maximal mechanical dissipation in which temperature‐dependent softening dominates strainand strain‐rate‐dependent hardening. In the simulations, the well‐known problem of the mesh‐dependence of the shear‐band development is addressed, involving both mesh size and mesh orientation. An example simulation is presented. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inconsistencies in Plane‐strain Elasto‐plastic Rolling Simulations
Authors: Kainz Alexander , Krimpelstaetter Konrad , Zeman Klaus 
Published: January 2007

AbstractPlane strain conditions are frequently used as model assumptions for the approximate calculation of flat rolling processes for sufficiently wide strips. This means that during the entire forming process, the strain rate in strip width direction (z‐direction) remains zero. In the case of elasto‐plastic material, the transitions from elastic to plastic states and vice versa are of particular interest. If we accept the flow rule of Levy‐Mises, the normal stress σzz equals the average value of the normal stresses σxx and σyy inside plastic domains. Using Hooke's law we obtain a different relation for σzz in elastic domains. At transition points from elastic to plastic domains and vice versa, above relations for σzz have to be fulfilled simultaneously. Generally, this yields a discontinuous behaviour of σzz at the transition points and consequently to discontinuities of the stress σyy as well as the strains εzz and εyy, provided a continuous behaviour of σxx in rolling direction is postulated. The resulting discontinuity of εzz indicates therefore an inconsistency of such a plane strain model. Some key aspects of the underlying theory and consequences of such model assumptions will be pointed out. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of stress and strain in tension cylindrical sample
Authors: Malag Leszek , Kukielka Leon 
Published: January 2007

AbstractOne of the basic engineering problem occurring during the numerical analysis is to define the function of yield stress of material in the real conditions of a technological process. These properties are necessary to calculate the deformation and the state of stress and strain in the surface layer of an object. An inappropriate selection of the mechanical properties of the material is the reason of the occurrence of errors in numerical calculations of a continuous object, considered as a boundary and initial problem. Scientific investigations are being conducted with the aim to develop a database concerning yield stresses for different metals, depends on complex conditions of thermo‐dynamical loads, e.g. temperature, the equivalent of the strain and the strain rate. The article presents a method of the determination of this dependence while using an experimental and numerical analysis. During the model investigations on the INSTRON testing machine, the force of elongation of the sample is measured and then calculations are made of the displacement of nodes of finite elements, plotted on outside surface of sample. The process is considered as a multi nonlinear problem. For this reason, an incremental method of motion and deformation of solid in an updated Lagrange formulation is used. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling of composites with a space‐varying microstructure
Authors: Woźniak Cz. , Michalak B. , Woźniak M. 
Published: January 2007

AbstractThe object of analysis is a microheterogeneous rigid heat conductor with apparent properties smoothly varying along the preferred direction. The aim of this contribution is to formulate two macroscopic models of this conductor. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
When to start supplementary iron to prevent iron deficiency in early childhood in sub‐Saharan Africa setting
Authors: Rahimy Mohamed Cherif , Fanou Lionnelle , Somasse Yassinme Elysee , Gangbo Annick , Ahouignan Gilbert , Alihonou Eusebe 
Published: January 2007

AbstractBackgroundTo study the efficacy of oral ferrous fumarate, an inexpensive, readily available preparation on iron deficiency in infants in Africa.ProcedureFour months old (group 1, n = 252) and 6–18 months old (group 2, n = 360) healthy infants attending four primary health care centers (PHC) for vaccination/well‐child visits in Benin were studied. Ninety‐six pregnant women (PW) over 36 weeks gestational age attending the same PHC during the study period were also studied. Infants were offered 2 months supplementation with oral powdered generic ferrous fumarate (GFF), that is, 5 mg/kg/day of elemental iron, given twice and were reevaluated 2 months later for hematological indices. The prevalence of anemia and iron deficiency among pregnant women was assessed using hematological indices and transferrin saturation.ResultsThe prevalence of anemia was 42.0%, 61.9%, and 37.5% in groups 1, 2, and PW, respectively. All anemic PW were iron deficient. Hemoglobin level shifted towards high values after supplementation. In addition, 24 infants from group 1 whose mothers interrupted the treatment, showed a significant decrease in hemoglobin level values, and similar improvement after two additional months of supplementation.ConclusionPrograms to prevent iron deficiency in Africa should utilize inexpensive preparations, start during pregnancy, continue in infants at 3 months of age and address problems of noncompliance. Pediatr Blood Cancer 2007;48:544–549. © 2007 Wiley‐Liss, Inc.
Incidence of childhood cancer in Switzerland: The Swiss childhood cancer registry
Authors: Michel G. , von der Weid N.X. , Zwahlen M. , Redmond S. , Strippoli M‐P.F. , Kuehni C.E. ,   For the Swiss Paediatric Oncology Group (SPOG)
Published: January 2007

AbstractBackgroundThis report describes the incidence of childhood cancer in Switzerland, based on the data from the Swiss Childhood Cancer Registry (SCCR), a national hospital‐based cancer registry with very high coverage, founded in 1976 by the Swiss Paediatric Oncology Group (SPOG).ProcedureMalignancies were coded according to the International Classification of Childhood Cancer (ICCC‐3). Incidence rates per 100,000 person‐years were calculated for all malignancies and groups of malignancies in Swiss residents less than 15 years of age for the decade 1995–2004.ResultsThe SCCR annually registered on average 174 new cases of cancer in Swiss residents aged <15 years, with a median age at diagnosis of 5.6 years. The crude incidence of childhood cancer in children aged <15 years was 13.5, higher for boys (15.0 per 100,000) than for girls (12.1 per 100,000), and was nearly twice as high in the first 5 years of life (19.3 per 100,000) than in the age group 5 to 14 years (10.8 per 100,000).ConclusionIncidence of childhood cancers in the SCCR was similar to neighbouring countries and to data published by regional cancer registries in Switzerland for the same period, suggesting good completeness of registration. This makes the SCCR a valuable resource for national and international research on childhood cancer. Pediatr Blood Cancer 2008;50:46–51. © 2007 Wiley‐Liss, Inc.
Facile synthesis of poly(hydroxyethyl acrylate) by frontal free‐radical polymerization
Authors: Chen Su , Hu Ting , Tian Yuan , Chen Li , Pojman John A. 
Published: January 2007

AbstractWe report the first synthesis of poly(hydroxyethyl acrylate) (PHEA) without solvent by free‐radical frontal polymerization (FP) at ambient pressure. In a typical run, the appropriate amounts of reactant (hydroxyethyl acrylate) and initiator (1,1‐di(tert‐butylperoxy)‐3,3,5‐trimethylcyclohexane) (Luperox 231) were mixed together at ambient pressure. FP was initiated by heating the wall of the tube with a soldering iron, and the resultant hot fronts were allowed to self‐propagate throughout the reaction vessel. Once initiated, no further energy was required for polymerization to occur. To study the macrokinetics, we also produced PHEA frontally with ammonium persulfate as initiator and dimethyl sulfoxide as the solvent. The dependences of the front velocity and front temperature on the initiator concentration and reactant dilution were investigated. The front temperatures were between 124 and 157 °C, depending on the ammonium persulfate concentration. Thermogravimetric analysis indicates that PHEA prepared by FP with ammonium persulfate as initiator had higher thermal stability than solvent‐free frontally prepared PHEA with Luperox 231 as initiator. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 873–881, 2007
Interlocking layer structures formed in spin‐cast polymer blend films by surface segregation and self‐stratification
Authors: Han Xia , Liu Honglai , Hu Ying 
Published: January 2007

AbstractSurface morphologies formed by the phase segregation of poly(styrene‐b‐ethylene/butylene‐b‐styrene) (SEBS)/poly(methyl methacrylate) (PMMA) blend films prepared via spin coating on mica substrates were studied with atomic force microscopy accompanied by a solvent extraction treatment, X‐ray photoelectron spectroscopy, and contact‐angle measurements. Three kinds of surface structures of films were observed. Besides the ribbonlike morphology and the dispersed domains in a continuous matrix that are common in this field, we found a special interlocking layer structure characterized by a smooth SEBS layer as the cover on the top and a layer composed of hill‐like PMMA dispersed in the SEBS matrix at the bottom when the composition of the film was around 50:50 SEBS and PMMA. A series of blend films with different thicknesses were then prepared to investigate the interfacial structure, and the formation process of the interlocking layer, which could be elucidated by a schematic diagram, was discussed. The interlocking bilayer film with SEBS on the top possessed high thermal stability and the best surface roughness in comparison with other structures. It might find important technical applications in fields such as adhesion, lubrication, and protective coatings. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 532–543, 2007.
Mechanical, thermo‐mechanical and piezoelastic properties of rare earth formates Y(HCOO)3·2H2O and Er(HCOO)3·2H2O
Authors: Bohatý L. , Haussühl S. , Becker P. 
Published: January 2007

AbstractLarge single crystals of the orthorhombic (point group 222) rare earth formate dihydrates Y(HCOO)3·2H2O (a promising candidate for Raman laser converters) and Er(HCOO)3·2H2O were grown. Thermal expansion and its temperature dependence (temperature range 140–300 K) as well as elastic, thermoelastic and piezoelastic properties (temperature range 270–320 K and hydrostatic pressure range 1 × 105 Pa − 1.6 × 108 Pa, respectively) were investigated and all components of the corresponding tensors [αij ], [cijkl ], d ln cijkl /dT and dcijkl /dp were determined (p = hydrostatic pressure). A detailed analysis of the aniso‐ tropy of the investigated properties shows a close correlation of extremal values of longitudinal and/or transverse effects with prominent structural features of the isomorphic compounds. All the investigated properties give evidence for structural stability of the two compounds and signalize their usability as a crystalline material. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)