Numerical analysis of the swage autofrettage process for cylindrical high pressure vessels

In this work the swage autofrettage process is examined with respect to the influence of design variables on the residual stress field remaining in a cylindrical pressure vessel after processing. A material model is derived that captures the behavior of high strength steel ASTM A723 during fully reversed plastic strain cycles, including the Bauschinger effect and changes in the elastic stiffness. An algorithm for implementing this material model in a finite element code is provided and the performance is demonstrated through simulation of the swage process with results compared to experimental strain data obtained during the swage process. A parametric study is performed that examines the influence of wall ratio and bore interference on the residual stress field.