Modeling Plastic Deformation of Structural Alloys under Block-Type Nonsymmetrical Regimes of Low-Cycle Loading

Abstract

Processes of plastic deformation of polycrystalline structural alloys under block-type nonstationary regimes of low-cycle loading are considered. A version of the yield theory with translational-isotropic hardening is used as defining relations. To describe the effect of setting of the plastic hysteresis loop for hard loading (controlled strains) and ratcheting for soft loading (controlled stresses) under block-type nonstationary regimes of low-cycle loading, a new evolutionary equation for the displacement of the yield surface center (macro-stress tensor) is introduced. The determination of material parameters and scalar functions of the plastic deformation model, as well as the assessment of its reliability and of the scope of its applicability was done based on the experimental investigations of deformation processes in laboratory specimens of stainless steels (SS316L, SS304) in the conditions of soft block-type cyclic loading and the experiments on plastic deformation of stainless steel 12 - 18 = 9 under hard block-type nonstationary nonsymmetrical low-cycle loading Comparison of the numerical results and the experimental data shows that the developed model of plasticity qualitatively and quantitatively, accurately enough for engineering purposes, describes the main effects of plastic deformation in the conditions of block-type nonstationary nonsymmetrical regimes of hard and soft low-cycle loading.