The saturated convex bending curvature of 7075 aluminum panel bent by orthogonal laser shock forming

Abstract

Laser shock forming is an innovative and flexible forming technology that induces bending deformation in thin panel by the action of laser shock wave. In the convex deformation, laser shock forming lacks the ability to continuously enhance the bending curvature for one panel, especially for thick panel. This paper explores the saturated convex bending curvature by increasing overlapping ratio, the number of repeated shock and laser power intensity sequentially in orthogonal laser shock forming. The induced bending moment and bending curvature are calculated by the average induced stress obtained from representative cell model, and this method improves the efficiency of evaluating the saturated bending curvature. 50% overlapping ratio can improve the bending curvature, and ensure the processing efficiency and quality of laser shock forming. The induced stress gradually tends to be saturated in the repeated shocks. Based on 50% overlapping ratio and 5 repeated shocks, when the laser power intensity exceeds 6.37GW/cm2, the bending curvature cannot be significantly improved by increasing laser power intensity for the saturation effect and the bending moment reduction. The curvature prediction method can effectively predict the saturated bending behavior of one panel in laser shock forming, and the method can avoid the invalid forming process design, which is a guidance for laser shock forming and the selection in forming methods.