Effects of oblique laser shock processing on rotary bending fatigue of aero-engine fan shaft

The circular bead of aero-engine fan shaft was obliquely shocked by laser shock processing(LSP). The shocking parameters were determined according to the analysis of the oblique laser shock model. After being obliquely laser shocked, the surface residual stress and micro-hardness of the aero-engine fan shaft were investigated and analyzed. Besides, the rotary bending fatigue tests and fracture analysis were also conducted. The experimental results show that the micro-hardness of the fan shaft increased about 11% by laser shock processing, which modified the inhomogeneity of the surface residual stress, and the rotary bending fatigue life of fan shaft increased by 160% after LSP. The fracture analysis show that the location of fatigue initiation migrated to a inner place of materials and the crack growth speed of fan shaft reduced by LSP, which is necessary for improving the fatigue life.