Research Of High-energy Ultrasonic Shot Peening Technology In Sheet Metal Forming

Ultrasonic shot peening (USP) is a green energy-saving sheet dieless forming technology.Compared with conventional shot peening forming process, it has the advantage of good surfacequality, high precision and easy to realize automatic control. So it is conducive to forming complexshape parts and has the broad application prospects in the field of aerospace, automotive cover partsand sheet metal manufacturing etc. The main works are as follows:The physical process and basic mechanism of USP sheet forming were analyzed. With Hertzcollision theory as the foundation, the forming process was analyzed with mechanics. The paper alsoestablished the relational model of sheet metal bending and the residual stress distribution andobtained the estimation formula of the sheet metal bending radius of curvature and arc height.Used microscope to observe and measure the diameter of the indentations made by USP in sheetsurface and the depth of the indentation was calculated next. The equivalent load of a pin impactingthe sheet was calculated through the dimensions of the indentations by empirical formula. Andaccording to the changes of the sheet specimen surface morphology and the grain, the effects of USPon sheet metal surface integrity in surface roughness and hardness was researched.The relationship between USP intensity, the pin diameter, USP time and the character of sheetbending deformation were investigated by the single rate part forming experiments. Made the severaltypical surfaces forming experiments according to the custom path and reached desired results. Testedsurface roughness and micro-hardness of the samples after forming and the results show that USPmethod can achieve good surface quality.On the basis of experiments above, the process of residual stress field and sheet bendingdeformation induced by USP were simulated by using ABAQUS software. Determined theappropriate model, constitutive model and mesh for UPS. Simulated the effect of strength, hammershot diameter and shot peening time to ultimate deformation of sheet metal. Made the simulation ofseveral typical surfaces forming according to the custom path, the results reach great agreement withthe experiments, which prove finite element simulation of UPS process is feasible.