ELASTIC-PLASTIC DEFORMATION OF INHOMOGENEOUS MATERIAL AND PARAMETRIC DESCRIPTION OF DEFORMATION-BEHAVIOR

The macroscopic elastic-plastic constitutive relation of inhomogeneous material is affected by the microscopic distribution of stress and strain in respective heterogeneous regions of the material. Several parameters are reviewed and a new parameter is proposed to describe the deformation behaviour of inhomogeneous material, and their relationship is discussed analytically as well as numerically. A plane model of inhomogeneous material composed of rectangular inhomogeneous regions was used for the numerical simulation, and the changes in the parameters during elastic-plastic deformation are calculated and compared. Uniaxial loading under plane strain condition is assumed. A modified plastic accommodations parameter is proposed, which is shown to be uniquely related to the constraint ratio reported previously. It is shown that the initial aspect ratio has a marked influence on the deformation behaviour. The process to estimate the constitutive relation of inhomogeneous material is also discussed on the basis of the constraint model.