Research on Autofrettage Mechanism in Ultra-High Pressure Thick-walled Vessel

Abstract

The stress distribution of the Ultra-High Pressure (UHP) vessel is uneven, the inner layer stress value is the maximum and the outer layer stress value is the minimum, resulting in insufficient utilization of the outer layer material and reduced fatigue strength. In order to obtain the pressure when the UHP vessel bursts into failure, this paper proposes a new formula for calculating the burst pressure and uses 30 experimental sample data to verify the accuracy. The error of the calculation result is about 5% lower than the error of the traditional Faupel burst pressure formula by 15%, and is not affected by the tensile strength.The UHP vessel improves the stress distribution and improves the fatigue life using autofrettage technology, reverse yielding does not occur when the best autofrettage pressure is unloaded, and the yield strength is calculated using the burst failure criterion method. Simultaneously, the Shigley method is used to predict the fatigue life of the autofrettaged UHP vessel to prove that its fatigue life has been significantly improved.