Implementation of plasticity model for a steel with mixed cyclic softening and hardening and its application to fatigue assessments

This paper presents a numerical modelling and experimental investigation of the cyclic plasticity behaviour of low carbon steel. In order to improve the accuracy of modelling the material response under cycling loading, a new set of internal variables is proposed. The developed plasticity model is applied to the problem of modelling compressive residual stress inducing methods which are based on a plastic overload of a material. A beneficial influence of induced compressive residual stress is demonstrated on a benchmark problem of autofrettage of a high pressure thick-walled cylinder. Numerical simulation of the cyclic plasticity problems and fatigue assessments are carried out by means of FEM in ANSYS Workbench with FORTRAN user-programmable subroutines for material model incorporating custom equations