Evaluating the effectiveness of combined hardening models to determine the behavior of a plate with a hole under combined loadings

Abstract

Geometrical discontinuities in a material such as holes and notches on machine elements are called as critical regions due to the stress concentrations. They are the potential failure initiation locations Therefore, researchers put significant effort on the prediction of the material response in these discontinuities under repetitive loadings. Cyclic plasticity is concerned with the nonlinear material response under cyclic loadings. In this study, numerical cyclic stress – strain response of a plate with a hole was evaluated under the combined loadings which are cyclic bending and tensile loadings. Oxygen Free High Thermal Conductivity (OFHC) Copper alloy was considered as material, and finite element simulations were performed in Marc software. A user defined material subroutine known as Hypela2 was utilized in order to define the material response. The plasticity model used in the present study comprises J2 plasticity along with combined isotropic – kinematic hardening model. Evolution of the backstress was introduced by Armstrong – Frederic type kinematic hardening model. The results were compared with the literature study, and it was seen that presented hardening model provides accurate results in small cyclic strain range.