Residual stresses in autofrettaged functionally graded pressurized thick cylinders

A popular process in the high-pressure vessel industry is the use of autofrettage to enhance the performance of thick-walled cylinders subjected to high internal pressure. This work focuses on nonlinear behavior of pressurized thick-walled cylinders made of functionally graded materials. The stress distributions in these cylinders are determined analytically using the Von-Mises yield criterion considering an elastic perfectly plastic material and taking into account the Bauschinger effect during unloading. Increasing the strength-to-weight ratio and extending the fatigue life of thick-walled cylinders are their two primary design goals. These goals can be met by generating a residual stress field in the cylinder wall before usage. The gradient index was made to vary from −2 to 2 and different cylinder aspect ratio ranging from 1 up to 3 are considered. Analytical and numerical methods are both utilized to examine how residual stresses affect load-bearing capability. •Analytical method to analyze the stresses and strains of autofrettaged FG hollow cylinders.•To generalize the approach the Ludwik power law and the Von Mises yield criteria are used.•The analytical approach is validated using numerical FE modeling.•Typical residual stress distributions are given for different elastic-plastic interface radii.•Material inhomogeneity significantly affects mechanical behavior in thick hollow cylinders of functionally graded materials.