Numerical Analysis of Peen Forming for High-Strength Aluminum Alloy Plates

Peen forming is a method of bending a metal plate by generating plastic strain near its surface when colliding with steel shots. In this study, the effect of coverage on the curvature after single-sided and double-sided peen forming of a high-strength aluminum alloy plate was investigated by experiments and finite element method (FEM) analysis. In the experiment, the curvature increased as the coverage increased in single-sided peen forming. In double-sided peen forming under the same peening conditions for both sides, the curvature is smaller than that after single-sided peening. FEM analysis was performed as follows. In step 1, multiple shot collisions were analyzed by the dynamic explicit FEM. In step 2, the plastic strain distributions analyzed in step 1 were input to the specimen to analyze the deformation by the static implicit FEM. FEM analysis results agreed with the experimental results in single-sided peen forming. In double-sided peen forming, the plastic strain distribution was calculated considering the residual stress distribution near the second surface after single-sided peen forming, and the analysis results agreed with the experimental results. A method of approximate calculation of the curvature was proposed, in which the plastic strain distribution was expressed as a function of coverage and initial stress. The curvature after single-sided and double-sided peen forming could be easily predicted by this method under various peening conditions.