Fatigue crack propagation under the condition where the superimposed stress history with different frequency components acts intermittently

In this study, fatigue crack propagation under the condition where the superimposed stress history with different frequency components was given intermittently was investigated by numerical simulation and fatigue crack propagation test. The numerical simulation of fatigue crack propagation used in this study can consider the opening and closing behaviour of fatigue crack and implement stress history extraction algorithm that contributes to fatigue crack propagation under superimposed stress history with different frequency components. An advanced fracture mechanics approach based on the RPG (Re-tensile Plastic zone Generating) stress criterion to identify the effective stress intensity factor range was applied to estimate the fatigue crack propagation history. Fatigue crack propagation test under superimposed stress history containing different frequency component appearing intermittently was also conducted. Validity of our applied numerical simulation method was investigated by comparing numerical simulation results with experimental ones. As a result, the validity of our proposed numerical simulation procedure to estimate the fatigue crack propagation history under such a complicated applied stress history was confirmed.