Microstructure-based constitutive law of plastic deformation

A macroscopic constitutive law of plastic deformation which accounts for the heterogeneous microstructure of the deforming material is proposed. It consists of a kinematic framework, kinetic equations, and structure evolution equations. The kinematic framework treats the material as a composite consisting of (plastically) soft cells or subgrains and hard cell walls or subgrain boundaries. The kinetic and structure evolution equations remain unspecified at first, the law being developed in a general way towards a system of ordinary differential equations. The proposed framework connects the heterogeneous microstructure with the macroscopic response independently of deformation mode and under arbitrarily varying deformation conditions. Two application examples are presented.