Researches on the curvature adjustment of metal sheet induced by laser shock forming through experiments and simulations

Laser shock forming (LSF) is an emerging method for metal sheet forming, and it can also be used to adjust the curvature of the curved metal. A series of laser shock adjustment experiments were conducted on 1-mm-thick curved aluminum 6061-T6 sheets using pulsed Nd3+:YAG laser operating at 1064-nm wavelength. The effects of various factors on the curvature adjustment were studied, including laser energy, impacted area, coverage rate of laser spots, and initial sheet shape. The mechanisms of curvature adjustment by LSF were studied by FEM simulation. The results have shown that the stress gradient mechanism and the shock bending mechanism were responsible for the two different kinds of deformation. The characteristic difference between the two mechanisms lies in whether the plastic deformation is directly induced on the bottom surface when the laser-induced shock wave is transmitted to the bottom surface. The curvature of the metal sheet can be adjusted conveniently within a certain range by changing the laser processing parameters, which is very useful for the engineering application.