Fatigue Life Prediction of the Rocket Engine’s Pipeline under Random Loads

Abstract

Based on the random vibration theory and numerical analysis method, the paper presents a process of carrying out the fatigue life prediction for pipeline of a rocket engine under random excitation. The numerical analysis adopt the power spectrum density of acceleration as random loads. The material parameters of the simulation contains two straight lines in double logarithmic coordinate. The location of danger points is found and the root mean square stress, fatigue life of it is acquired in different excitation directions. The results show that the root of the ball head is the location of danger points, whose fatigue life is 3763 seconds. Furthermore, the location of danger points and its fatigue life obtained from numerical analysis are consistent with the test.