Study on the effect of laser peening with different power densities on fatigue life of fastener hole

Laser shock processing can improve the fatigue life of fastener holes. The purpose of this study is to investigate the effect of laser power density on fatigue life and fracture characteristics of 7050-T7451 aluminum alloy fastener hole specimens with 6 mm thickness. ABAQUS software is used to analyze the three-dimensional stress distribution. The fatigue test was carried out and the treated specimens were evaluated by scanning electron microscope. The results show that with the increase of laser power density, the fatigue life gain of fastener hole specimens increases firstly, then decreases, and then increases again. The fatigue life gain of the fastener hole specimen is related to the initiation position of the fatigue crack and the direction of the crack propagation. It is speculated that this is closely related to the three-dimensional stress distribution of the fastener holes after laser shock processing in different laser power density.