Research Of Ultrasonic Shot Peening Forming Technology In Curved Surface Parts

Ultrasonic shot peening (USP) is an advanced technique widely applied on sheet metal formingand surface modification in recent years. Compared with conventional shot peening forming process,it has the advantage of high precision, good surface quality and easy to realize automatic control. So itis conducive to forming complex shape parts and has the broad application prospects in the field ofaerospace, automotive cover parts and sheet metal manufacturing etc. According to the theoryresearch, test research and the finite element theory to study USP sheet forming. The main works areas follows:The physical basic process, mechanisms and mechanics of ultrasonic shot peening sheet formingwas analyzed and surface induced residual stress was calculated.Relationship between the sheetbending and shot peening residual stress distribution was studied; formula for the sheet metal formingbending curvature radius and arc value are deduced.The relationship between forming trajectory, forming trajectory spacing, feed speed, currentintensity,the pin diameter and the character of sheet bending deformation were investigated by thesingle rate part forming experiments, the empirical formula between USP parameters and radius ofcurvature was established. In the meantime, the surface properties of AA2024with USP wascomprehensively studied, such as surface topography, surface roughness, hardness, surface residualstress and FWHM, searching for the best surface integrity.Finite element simulation was used to study ultrasonic shot peening forming process.The USPparameters influence on the radius of curvature and the induced residual stress field of sheet metalforming was investigated, and the relationship between residual stress distribution and the radius ofcurvature was established. Made the simulation of several typical surfaces forming according to thecustom path, the results reach great agreement with the experiments.Finite element simulation and forming trajectory optimization was used to simulate the formingof the curved surface parts and the amount of bending parts of the finite element simulation is verysimilar requirements to the final shape of the part, which prove finite element simulation of USPprocess is feasible.