基于不同随机退化过程的腐蚀管道时变失效概率

在进行腐蚀管道的时变失效概率分析时主要存在腐蚀管道失效状态的判定以及管道腐蚀退化过程的准确模拟两个问题。基于管道试验爆破数据,依据损失函数值最小选择了管道剩余内压承载力;将随机过程——伽马过程、逆高斯过程和维纳过程引入到计算腐蚀管道的失效概率中;结合蒙特卡洛法计算了管道的时变失效概率。以一组工况为例,分析了退化过程的类型和参数对管道时变失效概率的影响,并评价了确定管道剩余寿命的不同方法。结果表明,DNV-RP-F101规范公式相对更符合实际情况的管道剩余内压承载力表达式;使用随机退化过程模拟管道的时变失效概率可以很好地描述腐蚀增长的随机性,为预测管道时变失效概率提供准确可靠的结果。

Time-dependent failure probability of corroded pipelines based on different stochastic degradation processes

There are two main problems in analyzing the time-dependent failure probability of corroded pipelines:determination of the failure state of corroded pipelines and accurate simulation of the pipeline corrosion degradation process. Firstly, based on the pipeline test blasting data, the residual internal pressure bearing capacity of pipeline is selected according to the minimum function value. Secondly, the stochastic processes including Gamma process, inverse Gaussian process and Wiener process are introduced into the calculation of failure probability for corroded pipelines. Then the Monte Carlo method is used to calculate the time-dependent failure probability of pipelines. Finally, taking a set of working conditions as an example, this paper analyzes the influences of the type and parameters of degradation process on the time-dependent failure probability of pipelines, and evaluates different methods for determining the residual life of pipeline. The results show that the DNV-RP-F101 normal formula is the most suitable expression of the residual internal pressure bearing capacity of pipeline consistent with the actual situation. Using the stochastic degradation process to simulate the time-dependent failure probability of pipelines can well describe the randomness of corrosion growth and provide accurate and reliable results for predicting the time-dependent failure probability of pipelines.