Abstract: “Recent technologies provide new opportunities for the construction of heterogeneous vessels with adaptable material compositions called Functionally Graded Materials (FGM). In order to benefit the damage tolerance advantages of internal compressive residual stresses, one may organize an autofrettage process in the FGM vessel. The process consists of a high internal pressure loading and unloading cycle. In this paper the autofrettage of an FGM vessel with nonlinear distribution of heterogeneity is studied. Using the semi-analytic technique known as Variable Material Properties (VMP), residual fields of stresses are derived. To validate the analytical technique, the solution of a typical problem is compared with the Finite Element results of the ABAQUS software. Based on the developed VMP solutions the effects of some parameters such as the loading pressure and volume fraction distribution pattern upon the level of compressive residual stresses are studied.”

Keywords: Pressure Vessel, Residual Stresses, Kinematic Hardening, FGM, VMP