Investigation of the low-cycle fatigue life under multi-axial non-proportional loading

This paper provides a new damage parameter, which combines the critical plane theory, shear stress work, the micro-mechanism of fatigue damage and additional hardening. In addition, the non-proportional scale representing the grade of additional hardening is introduced as a friction coefficient. Based on this parameter, the relationship between the damage parameter and fatigue cycle is derived to build up a fatigue damage accumulation model using finite element program and numerical simulation. Effort is also focused on evaluating the fatigue life.