Abstract:Aiming at the problem of fatigue crack growth life of crack-containing pressure vessels, on the basis of the simulation of the safe attenuation path of crack defects, a calculation method for predicting the fatigue propagation life of crack defects was proposed. First, according to the geometric correlation change model of crack length and depth, based on the correlation model and failure assessment diagram (FAD), simulation of the safe attenuation path trajectory of crack defects was carried out. Then the mathematical integration method was used to solve the length of the safe attenuation path and the length of the remaining trajectory line segment. Based on this measurement, a calculation model of the crack defect safety margin and damage degree was proposed. Besides, combined with the low cycle fatigue test data, a prediction model of crack fatigue propagation life based on Lemaitre energy damage theory was established. In addition, this paper analyzed an example of a pressure vessel, and compares the calculation results of the model proposed in this article with the calculation results of Paris formula and the results of extended finite element simulation. The results show that this method has certain practical value for fatigue life assessment of crack defects in pressure vessels.