基于损伤力学与安全衰减路径的含裂纹缺陷压力容器扩展寿命分析

针对含裂纹缺陷压力容器的疲劳裂纹扩展寿命问题，在裂纹缺陷的安全衰减路径仿真基础上，提出了一种预测裂纹缺陷疲劳扩展寿命的计算方法。首先根据裂纹长度和深度的几何关联变化模型，基于该关联模型与失效评定图（FAD）仿真裂纹缺陷的安全衰减路径轨迹，然后采用数学积分方法求解安全衰减路径的长度和剩余轨迹线段长度，以此为度量建立裂纹缺陷安全裕度及损伤程度的计算模型，结合低周疲劳试验数据，在Lemaitre能量损伤理论上建立一种裂纹疲劳扩展寿命预测模型。此外，本文对某压力容器进行了算例分析，并运用本文提出的模型计算结果与Paris公式的计算结果及扩展有限元仿真的结果进行对比，结果表明，该方法对压力容器含裂纹缺陷的疲劳寿命评估有一定的实用价值。

Study on the Extended Life of Cracked Defects Pressure Vessel Based on Damage Mechanics and Safety Attenuation Paths

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.