Peen forming using rectangular solid pins for anisotropic double-curved surface

Abstract

Peen forming has been widely used in the aerospace industry for forming complex components of large thin wings. The conventional peen forming using spherical shots shows a tendency to form the spherical surface because of its axisymmetric plastic strain. In this study, a new peen forming method using rectangular solid pins is developed. It is possible to produce the different distribution between x direction (short side of pin) plastic strain and z direction (long side of pin) plastic strain. The anisotropic plastic strain distribution causes smaller curvature radius of x direction section than that of z direction section. In order to verify the anisotropic plastic strain distribution in this method, the effects of pin tip shape are analyzed by dynamic explicit finite element method. The ratios of x direction plastic strain to z direction plastic strain increase with decreasing pin tip radius. It is confirmed that anisotropic double-curved surfaces are produced by drop tests using multi- rectangular-solid pins.