基于概率断裂力学的管道疲劳寿命分析

采用奇异单元模拟裂纹尖端应力场的奇异性，计算裂纹尖端的应力强度因子和张开应力.以概率论为基础，结合确定性疲劳断裂力学估算方法，考虑参数的不确定性和随机性，应用蒙特卡洛模拟法分析管道的疲劳寿命.结果表明：通过J积分计算得到的裂纹尖端张开应力与计算得到的管道工作应力基本相等.采用蒙特卡洛模拟法进行的一定可靠度和置信度下的疲劳寿命预测能反映评定参数的不确定性，较传统的断裂力学计算结果更安全.

Pipeline fatigue life analysis based on probabilistic fracture mechanics

The singular element is used to simulate the singularity of stress field near the crack tip, and the stress intensity factor and the opening stress of crack tip are calculated. Based on probability theory combined with deterministic probabilistic fracture mechanics estimation method, the pipeline fatigue life is predicted using Monte Carlo method with consideration of the uncertainty and the randomness of the parameters. The results indicate that the opening stress calculated by J integration method can be nearly identical to the pipeline working stress. The fatigue life predicted by Monte Carlo simulation method under a certain degree of reliability and confidence can reflect the uncertainty of the parameters for estimation, and is safer than the results calculated by traditional fracture mechanics.