Numerical study on residual stress redistribution of shot-peened aluminum 7075-T6 under fretting loading

This study attempts to analyze the residual stress redistribution under fretting loading by using FEM. The FE analysis model used in this study considers the variation of surface yield strength, the evolution of contact surface profile and the variable friction coefficient. The initial residual stress of shot-peened specimen is measured by X-ray diffraction method. Nano-indentation experiment is conducted to measure the yield strength of material surface layer. Pin-on-plate wear experiment is used to measure the wear coefficient of shot-peened aluminum 7075-T6. A fretting experiment is designed to measure the friction coefficient and verify the FE analysis model. The results show that the relaxation of residual stress is more likely to occur near the trailing edge of contact area, and the specimen with higher shot peening intensity undergoes the larger residual stress relaxation. In addition, the residual stress near the contact center region increases with the increase of loading cycles due to the fretting wear.