Influence Rule of Process Parameters on Residual Stress Cave Induced by Laser Shock

The concepts of relative cave depth, relative cave width and stress loss ratio of residual stress cave were introduced by establishment of the residual stress cave math model. The effect of shock energy (1.0-3.0 J), spot diameter (1.0-3.0 mm), shock number (1-5 times) and spot overlap ratio (30%-70%) on residual stress cave was quantitatively analyzed by finite element model verified by experiment. The results show that stress loss ratios caused by residual stress cave were all very small, which were all less than 3%; relative cave widths were all less than 20%; the variation range of relative cave depths was large, which was 0-70%, and relative cave depth was the main factor to affect the uniformity of surface residual stress. In order to improve the uniformity of surface residual stress, when the relative cave depth of single residual stress cave was more than 10%, the spot overlap method should be used to shock peening, and the distance between two neighbouring spot center should be equal to the opening radius of the residual stress cave.