Papers by Keyword: Homogenization Method

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Authors: Yuichi Tadano, Mitsutoshi Kuroda, Hirohisa Noguchi, Kazuyuki Shizawa
Abstract: In this study, a three-dimensional finite element formulation for polycrystalline plasticity model based on the homogenization method has been presented. The homogenization method is one of the useful procedures, which can evaluate the homogenized macroscopic material properties with a periodical microstructure, so-called a unit cell. The present study focuses on hexagonal metals such as titanium or magnesium. An assessment of flow stress by the presented method is conducted and it is clarified how the method can reproduce the behavior of hexagonal metal.
Authors: Eisuke Kurosawa, Yoshiteru Aoyagi, Yuichi Tadano, Kazuyuki Shizawa
Abstract: In this study, the conventional Bailey-Hirsch’s relationship is extended in order to express the increase of critical resolved shear stress due to the lack of dislocation lines in a grain. This model is introduced into a triple-scale crystal plasticity model based on geometrically necessary crystal defects and the homogenization method. A FE simulation is carried out based on the proposed model for FCC polycrystals with different grain sizes. It is numerically predicted that yield behavior of fine-grained metals depends on the initial dislocation density and the initial grain size. Furthermore, yield point drop that is observed in annealed FCC fine-grained metal can be reproduced.
Authors: K. Saito, Shushi Ikeda, Koichi Makii, H. Akamizu, Yoshihiro Tomita
Abstract: Low carbon TRIP steel shows quite complicated deformation behavior. The main purpose of this study is to clarify the deformation mechanism of low carbon TRIP steel by using a numerical simulation method. According to research works in the past, continuous transformation of retained austenitic phase is essential in order that TRIP steel may show favorable ductility, which implies that appropriate control of martensitic transformation is most important for improvement of ductility. Therefore, we built models for deformation-induced martensitic transformation and performed FEM analysis using homogenization method accounting for the chemical composition, temperature, and crystal orientation. As a result, the effects of chemical composition, temperature, and crystal orientation on the deformation and transformation behavior of low carbon TRIP steel were clarified quantitatively and the conditions to realize improved ductility in TRIP steel were suggested.
Authors: Yu Hang Chen, Joseph Cadman, Shi Wei Zhou, Qing Li
Abstract: Computer-aided design (CAD) has proven effective in enabling novel approaches for tissue engineering applications. This paper demonstrates the applicability of various mathematical methods to design and fabricate bio-mimetic materials via two illustrative examples. Firstly, CAD models of cellular biomaterials that mimic the micro-structure of cuttlefish bone are designed based on the principles of the homogenization method. Secondly, a three-dimensional bi-objective topology optimization approach based upon the inverse homogenization method is used to design scaffold micro-structures with tailored effective stiffness and permeability properties. Consequently, solid free-form fabrication is used to fabricate such cellular bio-mimetic materials, which show a great potential in tissue engineering applications.
Authors: Ilya S. Nikitin, Nikolay G. Burago, Alexander D. Nikitin
Abstract: The equations for layered medium with slippage are obtained using the asymptotic method of homogenization. The terms of second order respectively the small parameter of layer thickness are taken into account. The linear slip condition defines the dependence between the tangential jumps of displacements at the contact boundary and the shear stresses. Such generalized models are needed in the study of static and dynamic deformations of layered rock media. Also these models may be useful for description of composite materials with additional soft sublayers between more rigid layers.
Authors: T. Tsujikami, M. Ohyanagi, Makoto Koizumi, E.A. Levashov, I.P. Borovinskaya
Authors: Hironori Nada, Masakazu Kudo, Junichi Takahashi, Toshiharu Yamamoto, Hideyuki Hara, Kazuyuki Shizawa
Abstract: Porous polymeric membranes are used for ion exchange membranes, membrane filter and separators of batteries owing to its micro-porous structure. Extension method is one of the inexpensive processes of such membrane. However, any suitable stability condition of the process has not yet been clarified. In this study, SEM (Scanning Electron Microscope) observations in production process are carried out and the simulation technology for production is developed for improvement in productivity. In this simulation model, the evolution equation of microscopic damage, constitutive equation depending on microscopic damage and the homogenization method are used for representation of evolution of micro-porous structure of crystalline polymer. It is indicated that numerical results obtained here are in good agreement with the SEM observations.
Authors: Gui Lan Xie, Ye Hua Liu, Shu Guang Gong, Jin Guo
Abstract: The micromechanical model for predicting macroscopic effective elastic coefficients of aluminum honeycomb cores is established based on homogenization theory combined with FEM method. The effects of aluminum honeycomb cell geometrical parameters on the efficiency of materials are investigated based on the concept of material efficiency. By using MATLAB language, the material efficiencies of irregular orthotropic hexagonal aluminum honeycomb cores with various height-to-length ratio, thickness-to-length ratio and cell wall angle are simulated. The effects of cell geometrical parameters on the efficiency of material are obtained. The light-weight design for aluminum honeycomb core is analyzed in further. The results have guiding signification for the optimization design and engineering application of aluminum honeycomb core materials.
Authors: Yoshihiro Tomita, Takenori Honma, Kisaragi Yashiro
Abstract: New finite element homogenization model with nonaffine constitutive equation of rubber is developed to study the deformation behavior of silica-filled rubber under monotonic and cyclic deformation. The obtained results clarified the effect of the volume fraction of the silica coupling agent and the networklike structure connecting the silica particles on essential physical enhancement mechanisms of deformation resistance and hysteresis loss for silica-filled rubber. The finding suggests that the material characteristics of silica-filled rubber are much more controllable than those of carbon-black-filled rubber.
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