Utilizing Finite Element Analysis to Accurately Predict Fatigue Life of Autofrettaged Ultra High Pressure Components

Computer Aided Design and Finite Element Analysis packages that have been developed are capable of providing a relatively accurate fatigue life prediction. These software packages have made nonlinear analysis more reliable in forecasting a component’s fatigue life. A safe-life (in which the components are safe from failure during the estimated service life) can be predicted during the design process. The autofrettage technique has long been applied in high-pressure industries in order to extend the components’ life. The critical parameters that must be understood during a fatigue life analysis are material properties, including cyclic loading properties and stress excursion during the service cycle. In this paper, a three-dimensional finite element analysis of an autofrettaged manifold is presented. This assessment investigated an ANSI 316 stainless steel Tee-fitting, which was exposed to different cyclical loading conditions (two autofrettage conditions at a normal operation level). This was done in order to compare finite element analysis results to actual laboratory experimental results.