Constitutive Modeling of Yield-Point Phenomenon in Finite Strain Elastoplasticity

Abstract

A standard elastoplastic constitutive model of metallic materials is extended to describe the stress-strain relationship including yield-point phenomenon. Based on a general framework of finite strain elastoplasticity, two constitutive models are formulated in this study. One of them is a phenomenological constitutive equation added one scaler internal variable. Another is a constitutive model based on a representative characteristic length defined as a dominant strengthening mechanism in some competing strengthening mechanisms including dislocation accumulations. The feature of these constitutive models is discussed by reproducing an experimental stress-strain relationship.