Experimental Verification and Estimation of Fatigue Crack Growth Delay due to Single Overload

Abstract

A novel crack driving force parameter based on the plastic zone size for overload/constant amplitude loading is proposed to estimate the fatigue crack growth (FCG) and the beneficial fatigue life due to overload. By considering the stress distribution in the plastic zone, the effective stress intensity factor (SIF) integrated from equivalent residual stress is presented. It is illustrated that the FCG rate decreases rapidly after overload and then gradually returns to the baseline FCG rate. Besides, the overload ratio Rpic has a significant influence on the affected length ad and the beneficial fatigue life Nd.