张鹏, 彭杨. 考虑随机变量相关性的腐蚀管道失效概率[J]. 石油学报, 2016, 37(10): 1293-1301. DOI: 10.7623/syxb201610010
引用本文: 张鹏, 彭杨. 考虑随机变量相关性的腐蚀管道失效概率[J]. 石油学报, 2016, 37(10): 1293-1301. DOI: 10.7623/syxb201610010
Zhang Peng, Peng Yang. Failure probability of corroded pipeline considering random variables correlation[J]. Acta Petrolei Sinica, 2016, 37(10): 1293-1301. DOI: 10.7623/syxb201610010
Citation: Zhang Peng, Peng Yang. Failure probability of corroded pipeline considering random variables correlation[J]. Acta Petrolei Sinica, 2016, 37(10): 1293-1301. DOI: 10.7623/syxb201610010

考虑随机变量相关性的腐蚀管道失效概率

Failure probability of corroded pipeline considering random variables correlation

  • 摘要: 针对腐蚀管道可靠性分析中随机变量独立性假设的缺点,提出了考虑随机变量相关性的腐蚀管道可靠性分析方法,建立了腐蚀管道腐蚀穿孔、局部爆破、整体断裂及其综合失效概率模型。基于JC法和正交变换法,运用多维正态分布函数,给出了随机变量相关下的腐蚀管道多模失效概率计算方法。对管道可靠性分析中的相关性进行了分析,结合实例研究了管径与壁厚、缺陷深度与长度、径向腐蚀速率与轴向腐蚀速率、屈服强度与拉伸强度4组随机变量相关性对腐蚀管道失效概率的影响。结果表明,随机变量相关性对管道腐蚀穿孔失效概率没有影响,管道局部爆破、整体断裂及综合失效概率随缺陷深度与长度相关系数和径向腐蚀速率与轴向腐蚀速率相关系数的增大而增大,随管径与壁厚相关系数的增大而减小。屈服强度与拉伸强度相关系数越大,局部爆破和整体断裂失效概率越大,综合失效概率不变,并且变量相关性对腐蚀管道失效概率的影响随着腐蚀增长而逐渐减弱。腐蚀管道失效概率对径向腐蚀速率与轴向腐蚀速率的相关系数最为敏感,对屈服强度与拉伸强度相关系数的敏感性最低。

     

    Abstract: In view of the shortcomings of independence assumption for random variables in the reliability analysis of corroded pipeline, an analytical method was put forward for the reliability of corroded pipeline considering the correlation among random variables. The models of corrosion perforation, local burst and rupture as well as their composite failure probability were also established. Based on JC method and orthogonal transformation, the multidimensional normal distribution function was used to propose a computational method for the multi-mode failure probability of corroded pipeline considering correlated random variables. This paper elaborated on the correlation of pipeline reliability analysis. Meanwhile, based on case studies, a study was conducted on how the pipeline failure probability was affected by the correlation between 4 pairs of random variables, including pipe diameter and wall thickness, the depth and length of the defect, the radial rate and axial rate of corrosion, as well as yield strength and tensile strength. The analysis results suggest that the correlation between random variables has no influence on the failure probability of pipeline corrosion perforation. The probability of local burst, rupture and composite failure increases with the increase of correlation coefficient between the defect depth and length as well as that between the radial and axial corrosion rate, and decreases with the increase of correlation coefficient between the pipe diameter and wall thickness. The larger the correlation coefficient between yield strength and tensile strength is, the greater the probability of local burst and rupture will be, while the composite failure probability remains the same. Besides, the impact of variables correlation on the failure probability of corroded pipeline decreases as the corrosion continues. The failure probability of corroded pipeline is most sensitive to the correlation coefficient of radial and axial corrosion rate, and least sensitive to the correlation coefficient between the yield strength and tensile strength.

     

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