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Kasahara, Naoto*; Takasho, Hideki*; Kawasaki, Nobuchika; Ando, Masanori
Proceedings of International Symposium on Plasticity 2010 (CD-ROM), p.34 - 36, 2010/01
The method to determine equivalent solid materials of perforated plates was proposed. One of difficulties of plastic analysis is dependency of their solutions on constitutive equations. To overcome this problem, plastic behaviors of perforated plate were systematically investigated on various kinds of constitutive equations. These studies have found existence of the effective stress ratio (ESR) which is defined as the stress ratio between average stress of perforated plates and solid plates of base materials. The ESR is a function of geometrical parameters and is independent from constitutive equations. Therefore, the ESR can determine plastic solid materials of perforated plates from any kind of constitutive equations of base materials.
Aoyagi, Yoshiteru; Shizawa, Kazuyuki*
no journal, ,
Ultrafine-grained metals whose grain size is less than one micron have attracted interest as high strength materials. In this study, in order to predict spontaneous dislocation patterning, generation rate of mobile dislocations is newly introduced into reaction-diffusion model. Information of deformation is related with the reference dislocation density through the generation rate depending on stress and activity of other slip system. In addition, carrying out pseudo-three-dimensional FE simulation for severe compression of FCC polycrystal using a multiscale crystal plasticity model based both on dislocation patterning and accumulation of geometrically necessary dislocations, we predict numerically the processes of ultrafine-graining of FCC crystal. We investigate comprehensively the effect of dislocation behaviors on the processes of ultrafine-graining.