基于概率断裂力学的管道失效分析

Pipeline failure analysis based on probabilistic fracture mechanics

针对油气管道的断裂失效模式以及失效分析过程中存在的不确定性 ,结合概率断裂力学和安全评定规范 ,提出了管道缺陷失效概率计算方法。根据主要评定参数 :缺陷尺寸、工况载荷、断裂韧性、机械强度的分布特征 ,对各随机变量模拟抽样 ,应用MonteCarlo数值计算方法确定管道上各缺陷的失效概率。可靠性失效评定方法确实反映了评定参数客观存在的不确定性 ,克服了确定性失效评定方法的缺点 。

Aiming at the fracture failure mode of oil gas pipeline and the uncertainty existed in the course of failure analysis; a calculation method for failure probability of piping defects was put forward with the combination of probabilistic fracture mechanics and specifications of safety assessment. According to principal assessing parameters, such as defect sizes, loads in working status, fracture toughness and distribution characteristics of mechanical strength, the simulative sampling of each random variable was made, and the failure probability of each defect in the pipeline was determined by applying the Monte-Carlo value calculation method. The reliability failure assessment method really reflected the objective existed uncertainty of parameter assessment and overcame the shortcomings of certainty assessment method. Thus it has a very high value of application.