Monte Carlo方法在管道裂纹缺陷评价中的应用

Application of Monte Carlo Method in Evaluation of Crack Defects in Pipes

某输气管道经过内检测后检测出了大量管体裂纹缺陷,为定量分析管体裂纹缺陷的失效概率,总结了基于可靠性的结构完整性评价方法。根据英国标准BS 7910:2013《金属结构缺陷可接受性评价指南》,对该输气管道管体裂纹的可接受性分别进行了确定性评价和基于Monte Carlo法的可靠性评价,并对两种评价方法进行了对比分析。确定性评价的评价结果只能给出缺陷是否可接受且是否受考虑分项安全系数的影响较大,而通过Matlab编程计算,得到使用Monte Carlo法模拟107次该管道的失效概率为3.17×10-3。基于可靠性的结构完整性评价可以对油气管道管体裂纹缺陷定量评价分析,与确定性评价相比,基于可靠性的结构完整性评价更便于管道管理部门对管道失效风险和维修维护费用作出权衡,对及时作出合理的维修维护决策更具有指导意义。

A gas pipeline was reported to have a large number of pipe body crack defects after in-line inspection. For the quantitative analysis of the failure probability of pipe crack,this paper summarizes the structural integrity assessment method based on structural-reliability analysis. According to the British standard BS 7910： 2013,certainty evaluation method and structural-reliability analysis evaluation method based on Monte Carlo simulation were carried out to evaluate the acceptability of the gas pipeline pipe body crack defects,and two kinds of evaluation methods were analyzed comparatively. The certainty evaluation results can only show whether the defects are acceptable or not and whether the partial factor is considered or not has great influence,and through the Matlab programming calculation,the pipeline failure probability is 3. 17×10^-3 after the 107 simulation using Monte Carlo. The structural integrity assessment method based on structural-reliability analysis can analyze the failure probability of oil gas pipeline pipe body crack defects quantitatively. Compared with the certainty evaluation,the structural integrity assessment method based on structural-reliability analysis is more convenient for pipeline management departments to balance pipeline failure risk and maintenance cost, which is of great significance for guiding reasonable maintenance decision-making.