【摘要】 针对输气管段多缺陷间相互联系的特点以及多缺陷高度非线性耦合作用难以量化的问题，提出基于Copula函数的含多缺陷输气管段结构可靠性评价方法。首先，基于不同缺陷对应的管段极限状态方程，采用蒙特卡罗法(MC)计算单缺陷作用下管段的失效概率和概率分布;其次，将各缺陷概率分布作为随机变量，通过Copula函数研究不同缺陷间相关性对管段失效概率的影响，得到2缺陷耦合作用下管段的联合失效概率;然后，基于二阶窄界理论确定含多缺陷输气管段可靠度;最后，探究腐蚀和裂纹缺陷间相关性对输气管段结构可靠性的影响，分析在不同缺陷深度和壁厚之比(0.2～0.8)条件下管段可靠度的变化。结果表明:在缺陷失效概率量级一致且相差不大的条件下，同种缺陷相关性更强且耦合作用对管段失效概率影响更大;相较于传统串联方法考虑缺陷间相互独立低估管段的可靠度，文中方法管段结构可靠性评价结果更符合实际需要，可为含多缺陷输气管段的稳定运行提供理论支持。更多还原

【Abstract】 A structural reliability evaluation method for gas pipeline segments with multiple defects,based on Copula functions,was proposed to address the characteristics of the interrelationship between defects and the difficulty in quantifying the highly nonlinear coupling effects of multiple defects. First,based on the limit state equations of pipeline segments corresponding to different defects,Monte Carlo( MC) method was used to calculate the failure probability and probability distribution of pipeline segments under the influence of a single defect. Second,the probability distribution of each defect were treated as random variables,and the Copula functions were employed to study the impact of the correlation between different defects on the pipeline failure probability. The joint failure probability of the pipeline segment under the coupling effect of two defects was obtained. Third,the reliability of the pipeline segment with multiple defects was determined based on the second-order narrow-bound theory. Finally,using this method,the impact of the correlation between corrosion and crack defects on the structural reliability of gas pipeline segments was explored,and the variation of pipeline reliability was analyzed under different defect depths and wall thickness ratios( 0. 2-0. 8). The results show that,under the condition that the failure probabilities of the defects are at the same order of magnitude and do not differ significantly,the correlation of the same type of defects is stronger,and the coupling effect has a greater impact on the pipeline failure probability. Compared with traditional series methods that assume independence between defects,which underestimate the pipeline reliability,the results of this method are more consistent with practical needs. This approach provides theoretical support for the stable operation of gas pipeline segments with multiple defects.更多还原