Fatigue damage

A healing method for fatigue damage was investigated by laser shock peening and laser irradiation with excimer laser for polycrystalline copper film. It is found that the sum of the consumed fatigue ductility and the total fatigue ductility for damaged specimen after both laser treatments is equal to the total fatigue ductility for undamaged specimen after both laser treatments. According to the relationship of plasticity, two variables are defined. One is healing variable and the other one is enhancement variable. Based on the relationship of damage variable, healing variable and enhancement variable, a residual fatigue life prediction method is proposed. The results show that the predicted lives by the proposed method agree well with the experimental results