Research on the edge effect of 7075 aluminium alloy damaged aircraft component strengthened by laser shock peening

Laser shock peening (LSP) is a promising surface strengthening process in the field of aircraft maintenance. However, unreasonable residual stress distribution often exists at the edge of the damaged aircraft component strengthened by LSP, which results in a significant decrease in strengthening effect of LSP. To explore the residual stress distribution after LSP in the edge region of components and reveal the influence of edge effects on deformation and inducing residual stress, the finite element (FE) models of LSP on 7075 aluminum alloy was established based on ABAQUS. The reliability of the FE model was verified by comparing the experiment and simulation results. The residual stress distribution in the edge and center region after LSP were analyzed. The results show that the edge effect enhances the flow of material to the edge and introduces tensile stress in this direction, thereby reducing the overall residual compressive stress level in the edge region. The influence range of edge effect on residual stress distribution is about 70% of the laser spot diameter. Besides, edge effects reinforce the phenomenon of residual stress holes, which results in a reduction of the maximum value by 109.2MPa. The influence of edge effect can be solved by multi surfaces LSP.