Abstract

This study aims to investigate the effects of correlation of random variables between the adjacent components on time variant system reliability of corroded pipelines. The system reliability analysis is conducted using a combination of Latin Hypercube Sampling and Cholesky decomposition methods for four different failure modes (Composite (C), Corrosion Perforation (CP), Local Burst (LB) and Rupture (R)). Since the multivariate target correlation matrix might be non-positive definite, a combination of two efficient optimization techniques is implemented to find the minimum perturbation for transforming the non-positive definite correlation matrix into a positive definite one. The findings of the paper indicate that there is no monotonic order in either lower or upper bound of the system failure probability of corroded pipelines with uniform variation in target correlation matrix. Furthermore, some correlations can change the upper bound of the system failure probability of corroded pipelines about 10%. In addition, the cumulative upper bounds of the system failure probability of the investigated case study for C, CP, LB and R failure modes reach unity after 9, 10, 11 and 13 years, respectively.

摘要

本研究旨在研究相邻构件之间随机变量的相关性对腐蚀管道时变系统可靠性的影响。针对四种不同的故障模式（复合 (C)、腐蚀穿孔 (CP)、局部爆裂 (LB) 和破裂 (R)），使用拉丁超立方采样和 Cholesky 分解方法的组合进行系统可靠性分析。由于多元目标相关矩阵可能是非正定的，因此实施了两种有效优化技术的组合，以找到将非正定相关矩阵转换为正定矩阵的最小扰动。论文的研究结果表明，在目标相关矩阵均匀变化的情况下，腐蚀管道的系统故障概率的下界或上界均不存在单调顺序。此外，一些相关性可以将腐蚀管道的系统故障概率上限改变约 10%。此外，C、CP、LB 和 R 故障模式的研究案例研究的系统故障概率的累积上限分别在 9、10、11 和 13 年后达到统一。