Extension of Subloading Surface Model and Its Application to Metals : 1st Report, Formulation of Constitutive Equation

Abstract

The subloading surface model is the only elastoplasticity model which fulfills the smoothness condition and thus describes always the continuous variation of tangent stiffness modulus leading to the smooth stress-strain relation. Then, it does not require to incorporate the algorithms for the judgment of yielding, i.e. the judgment whether or not the stress reaches the yield surface and for pulling back the stress to the yield surface. It is refined so as to describe the unloading-reloading behavior pertinently in this article. Then, based on this model, the constitutive equation of metals is formulated introducing the cyclic stagnation of isotropic hardening with substantial modification based on the concept of subloading surface. The applicability of the present model to the description of real deformation behavior of metals is verified by comparisons with various test data for cyclic loadings.