Fatigue life simulation and estimation of an autofrettaged thick-walled pressure vessel with an external groove

Fatigue tests that simulate an autofrettaged thick-walled pressure vessel with an external groove under pulsating internal pressure loading conditions were performed using specimens taken from an autofrettaged thick-walled pressure vessel. Load-controlled simulation fatigue tests using rectangular, elliptical, and shot-peened elliptical grooved specimens were performed for three different autofrettage levels of 50, 75, and 100% overstrains. In order to estimate the fatigue life of the pressure vessel subjected to pulsating internal pressure, a local strain approach was considered to access the crack formation life. A cyclic stress-strain relation and fatigue damage models determined from strain-controlled low-cycle fatigue tests were employed to estimate the fatigue life of the pressure vessel. Larger local stresses and strains obtained from Neuber's rule compared with the linear rule led to the conservative fatigue life estimations. Estimated fatigue lives were obtained within factors of 2-4, compared with the experimental fatigue lives determined from the simulation fatigue tests.