Section 6: Material modelling in solid mechanics - GAMM 2012

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24 Section 6: Material modelling in solid mechanics individual materials constituents. It was found that for the considered composites have place the additional peak damping properties, which is realized for very small thicknesses of the viscoelastic phase. This peak is still about a factor 20 or so compared to the loss modulus of the pure matrix. We demonstrated that by introducing thin layers of a viscoelastic material, one can significantly increase the loss characteristics of discrete morphology multiphase materials. The layered fibers composites are also considered. It is shown that for such materials may be implemented at the same time as high elastic properties, and abnormally high damping properties. [1] A.A.Gusev , S.A. Lurie, Loss amplification effect in multiphase materials with viscoelastic interfaces. Macromolecules (2009) 42,14, 5372 – 5377. Modeling of composite structural elements made from aramid fiber using the method of features objects Michał Majzner, Andrzej Baier (Silesian University of Technology) The use of modern materials such as composite materials, enabling the production of new or modifying existing design solutions, improve their technical characteristics, while use in the process of design and engineering and manufacturing, will allow the modification of endurance, physical and chemical properties to match the features and functionality that are comply with. In research studies, it is proposed to systematize and formalize elementary objects in the context of modeling and fabrication of objects created on the basis of structural fiber composites. Application of features objects methods was shows on an example of modeling the structural element, in the form of an existing manufactured from steel, which was modified and converted with aramid fiber. It was necessary to carry out research in the form of numerical analysis, examining the strength of the modified object. On the fibres shape effect for non-linear and unidirectional stationary heat conduction in two-phase hollow cylinder with radially graded material properties Piotr Ostrowski (Technical University of Lodz) The main aim of this paper is to consider unidirectional and stationary heat conduction in the infnite two-phase hollow cylinder with temperature dependent material properties. The deterministic microstructure of this composite is periodic (for a fixed radius) along the angular axis and has slowly varying effective properties in the radial direction. Therefore, we deal here with a special case of functionally graded materials, FGM, c.f. Suresh, Mortensen (1998). One of the components is called fibre, which is arranged in considered hollow cylinder with circular pattern. The physical phenomenon of the heat transfer is described by well known Fourier’s equation c ˙ θ − ∇(K∇θ) = 0, (1) which contains temperature dependent (in this case), highly oscillating and discontinuous coefficients of K = K(θ) - heat conduction tensor, and c = c(θ) - specific heat. To this macroscopic model the tolerance averaging approximation will be used, cf. Wozniak, Wierzbicki (2000). The general approach to the description of longitudinally graded stratified media can be found in [Wozniak, Michalak, Jedrysiak 2008]. The fibres width function g = g(r) of radius r will be examined and its effects on the temperature field. The averaged differential equation has smooth and slowly varying coefficients, hence in some special cases, for boundary value problem, analytical solution can be obtained. In other cases, numerical methods have to be used. This model takes into account the effect of microstructure size on the overall heat transfer behaviour.
Section 6: Material modelling in solid mechanics 25 [1] S. SURESH, A. MORTENSEN, Fundamentals of functionally graded materials, Cambridge, The University Press, 1998. [2] Cz. WOZNIAK, B. MICHALAK, J. JEDRYSIAK (eds), Thermomechanics of micro-heterogeneous solids and structures. Tolerance averaging approach, Wydawnictwo Politechniki Lodzkiej, Lodz, 2008. S6.10: Elasticity, Viscoelasticity, -plasticity III Thu, 13:30–15:30 Chair: Daniel Balzani S1|01–A1 Network evolution model: thermodynamics consistency, parameter identification and finite element implementation Vu Ngoc Khiêm, Roozbeh Dargazany, Mikhail Itskov (RWTH Aachen) In this contribution, the previously proposed network evolution model [1] for carbon black filled elastomers is further studied. First, we show that the model does not contradict the second law of thermodynamics and is thus thermodynamically consistent. On the basis of new experimental data the influence of filler concentration on the material parameters is further examined. Accordingly, this influence concerns only three material parameters and is approximated by phenomenological relations. These relations enable one to simulate rubbers based on the same compound with various filler concentrations. Finally, the model is implemented to the FE-Software ABAQUS and illustrated by a number of numerical examples. The examples demonstrate good agreement with experimental results with respect to the Mullins-Effect, permanent set and induced anisotropy. [1] R. Dargazany and M. Itskov, A network evolution model for the anisotropic Mullins effect in carbon black filled rubbers, International Journal of Solids and Structures 46 (2009), 2967–2977. Shakedown analysis of periodic composites with kinematic hardening material model Min Chen, A. Hachemi, D. Weichert (RWTH Aachen) Lower-bound limit and shakedown analysis of periodic composites with the consideration of kinematic hardening are investigated on the representative volume element. With the combination of homogenization theory, the homogenized macroscopic admissible loading domains are evaluated. Furthermore, the strengths of periodic composites of elastic-perfectly plastic, unlimited and linear limited kinematic hardening material models are calculated and compared in this paper. Theory of mixture based material modeling - An inelastic material model for a 12%chromium steel Andreas Kutschke, Konstantin Naumenko, Holm Altenbach (Universität Magdeburg) Components composed of advanced heat resistant steels face a complex loading of mechanical and thermal stresses under cyclic and long-term conditions. Additionally, a failure of these components usually has serious outcome, because of the extreme working conditions. From this follows the need of a reliable material model for the construction process. Classical technical guidelines are historically grown and the experience of engineers contributed to their development, but it turns out that these classical guidelines face their limit of use. Recently more sophisticated material models are developed to reach the real limit of the materials and to predict their behavior with more accuracy.
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Section 6: Material modelling in solid mechanics - GAMM 2012

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