Analytical prediction of shot peening residual stress distribution using inherent strain in aluminum-magnesium alloy plates under various peening conditions

The compressive residual stress distribution in shot peening can be simulated using the nonlinear elastic-plastic finite element method (FEM) or obtained using various measurement methods; however, a simple and efficient prediction is desirable for practical applications. The residual plastic strain component produced by shot peening, known as the inherent strain or Eigenstrain, has a simple distribution and can be used to predict the residual stress via linear elastic analysis. In this study, the residual stress distributions in aluminum-magnesium alloy plates due to various shot velocities and shot diameters were simulated using the nonlinear FEM; further, the residual stress distributions were verified using the X-ray diffraction method. The inherent strain was identified using these results as datasets, and the strain distribution was quantitatively expressed using a simple equation. Finally, an analytical method for shot peening residual stress prediction using inherent strain and plate bending theory was developed. The residual stress distributions predicted from the inherent strain determined for 5 -mm-thick plate were consistent with the experimentally measured and numerical simulated results for 2-, and 1 -mm-thick plates with different shot blasting machines and shot diameters.