Abstract: Aiming at the problem that the amount of shot peening deformation required for the large-curvature biconvex shape and high stiffened integral panel exceeded the limit of the traditional shot peen forming process, a new method of stretch-bending stress peen forming is proposed based on increasing the tensile stress of the outer surface of the skin in the length direction of the ribs. Firstly, the principle, classification and characteristics of stretch-bending prestressing are expounded, and the method of stretch-bending stress peen forming is explained. Secondly, the new technology of stretch-bending prestressing and the new technology of stretch-bending stress peen forming are studied. Using the finite element method of reverse bending stress field method, the numerical simulation analysis of stretch-bending stress peen forming is carried out, and the numerical simulation results of tensile stress peen forming and bending stress peen forming are compared and analyzed. Finally, the experimental research and verification of stretch-bending stress peen forming is carried out, and the mathematical model between the stretch-bending stress peen forming deformation and its process parameters is established, which is provided an important means and approach for the analysis and application of stretch-bending stress peen forming. The research results shows that for the large-curvature biconvex shape and high stiffened integral panel, the stretch-bending stress peen forming could improve the prestress in the length direction of the ribs, and increase the stress peen forming deformation in the length direction of the ribs, which can realize and satisfy its long-life shot peen forming.

Key words: integrally-stiffened panel, prestress, elastic stretch-bending, finite element method, shot peen forming