Identification of combined hardening model parameters by considering pre-tensile stress for 2024-T3 aluminum alloy

Abstract

The nonlinear hardening of the initial cycle is quite different from subsequent cycles under cyclic loading because of pre-tensile stress in work hardening metal materials. This paper investigates parameters of nonlinear combined hardening model by considering the effect of pre-tensile stress. The parameters of combined hardening model were fitted by three kinds of cyclic loading test data of 2024-T3 aluminum alloy. The finite element simulation with initial conditions representing the pre-tensile stress and experiment were analyzed to illustrate availability of calibration method of hardening parameters. The ratchet effect of asymmetric cyclic loading was predicted. The results show that compared with the curve without initial conditions, the changing trend of simulated stress-strain cyclic curves with initial conditions is more consistent with that of the test curve. The effect by adding initial condition elastic-plastic mechanical behavior in stress controlled loading becomes more pronounced than strain controlled loading. Under different loading modes, the metal materials exhibit cyclic hardening, average stress relaxation, ratchet effect and other cyclic effects. These results are of great significance for understanding the elastic-plastic deformation behavior of metal materials.