Generalization of strain theories of plasticity based on energy concepts

Abstract

For steady loading of Isotropic polycrystalline materials it is shown that based on the principle of a maximum in the increment in work of plastic strain with introduction of the work of elastic change in form functionally related to it the presence in the general case of two stages of hardening is necessary. Analytical equations for the functions of hardening very accurately describing the tensile curves of materials and equations of plastic strain in the complex stressed state bounding the areas of use of known strain theories are obtained. A modified method of variable hardening parameters is proposed for solution of applied problems within the limits of a theory taking into consideration two-stage hardening of materials.