埋地管线面积腐蚀率概率密度的模拟分析

利用马尔可夫过程,提出了管线腐蚀的发生模型,然后结合线性腐蚀发展模型,采用全概率公式,给出了埋地管线面积腐蚀率随服役时间变化时的概率密度函数解析表达式.将腐蚀发展模型中的参数分别考虑为确定变量和随机变量,推导出管线面积腐蚀率概率密度函数的具体表达式.结合具体的算例模拟分析,给出了管线面积腐蚀率概率密度函数随服役时间增加的演变过程.计算结果表明,模型可以很好地估计管线在使用过程中腐蚀的演变规律.

Simulation Analysis for Probability Density of Buried Pipeline''''s Area Corrosion Ratio

In order to obtain the evolution of buried pipeline corrosion during the service time,Markov process is used to simulate the occurrence of corrosion on the pipeline and the probability of the occurrence of corrosion at the time of t is derived.Combining with linear corrosion development model,the evolution of probability density function of buried pipeline's area corrosion ratio as service time increases is derived on the basis of total probability formula.When the corrosion ratio parameters in corrosion development model are considered as deterministic or stochastic respectively,different condition probability density functions of pipeline's area corrosion ratio can be obtained.So different probability density function are derived for deterministic and stochastic corrosion ratio parameters.A pipeline which is 325 mm in diameter and is 16 mm in thickness is investigated in detail with deterministic and stochastic corrosion rate parameters respectively to validate the proposed approach.The results indicate that the proposed approach can efficiently simulate the evolution of probability density function of buried pipeline's area corrosion ratio as service time increases.