Model of viscoplasticity with parallel deformation mechanisms. Part 1. Constitutive equations and choice of calculation coefficients*

Abstract

A model of viscoplastic deformation of strengthening material is proposed. It is assumed that metal deformation is determined by two independent (parallel) mechanisms. Each of these mechanisms corresponds to anisotropic creep theory with linear strengthening, within which an isotropic strengthening parameter is introduced for both mechanisms. The concept of surface flow is not used. The model describes material behavior at both normal and elevated temperature when thermal recovery effects develop. Results of standard tensile and creep tests are used in order to determine model parameters. The order of determining model parameters from standard tensile and creep tests is provided. Features of austenitic stainless steel cyclic strengthening are considered. An algorithm is given providing implementation of the proposed viscoplasticity theory in structural design using FEM computer packages.