Research on torsion deformation of integral stiffened panel by pre-stress shot peen forming

Abstract Pre-stress shot peen forming is the main plastic forming method for obtaining complex torsional shape of integral stiffened panel . The elastic pre-bending method of maximum torsion angle was optimized with finite element analysis for the AA7050 integral stiffened panel. Besides, shot peen forming area and parameters were designed. The results show that the maximum pre-bending torsion can be achieved by applying a "pushing" force on two diagonal points of the external surface and a "retaining" force on the central internal area of the middle rib. After shot peen forming with large shots in specific area, the exterior surface of the panel presents double curvature change which displayed twisting characteristics. Moreover, the angle along the two end chord lines is 3.1o. The test results of the exterior torsion curvature meet the requirements of aircraft wing panel, which can provide data reference for the subsequent process design.