Numerical Study on Cyclic Crystalline Slip Deformation of Polycrystalline Metallic Material by Homogenization Method

摘要

Cyclic crystalline slip deformations of a bulk body and a center-crackedplate consist of polycrystalline metallic media subject to cyclic loadingsare investigated by using newly developed homogenized crystallineelastic-plastic FE theory which can take into account cyclic crystallineslip. Both coupling and Terada-and-Kikuchi's decoupling schemes areadopted. Localization and homogenization analyses are performed inthe user subroutine of a commercial nonlinear FE code. Hill'sanisotropic elastic-plastic constitutive relation, which cannot simulatecyclic hardening or softening, is adopted in the decoupling scheme. Asresults, it is found that the decoupling scheme can simulate themacroscopic stress-strain relation during the preloading of models withand without stress gradient, but the stress-strain relation and the shearslip deformation after the reloading show significant difference. It isnot appropriate to apply the decoupling scheme that uses a constitutiveequation which cannot simulate cyclic hardening or softening to themicroscopic slip deformation analyses in fatigue crack problems.