The mechanism of stress interaction induced by successive impacts in shot peening and wet peening zone

Coverage is obtained by the superposition of several random adjacent impacts with different relative positions. The relative position of indentations and the stress interaction have a significant influence on the residual stress distribution. The double impact model is designed to reveal the mechanism of stress interaction during the successive impacts, which could introduce indentations with different overlap degree. Attention is devoted to the characteristics of elastoplastic deformation and stress superposition, as well as the effect of overlap ratio on residual stress in the process of successive impacts. The results show that the stress generated by the successive impacts of two shots is superimposed along the loading/unloading stress-strain curve. Under the subsequent impacts, the compressive residual stress induced by the previous impact is partially relieved or reinforced, which is affected by the overlap ratio. The residual stress distribution is optimal when the overlap ratio is between 75% and 90%.