基于BDD考虑共因失效的多阶段任务系统可靠性分析方法

Reliability Analysis Method of Phased-Mission Systems With Common Cause Failure Based on BDD

多阶段任务系统同一部件或不同部件之间在不同任务阶段存在的相关性,对系统可靠性分析结果的准确性有着重要的影响。当考虑多阶段任务系统部件之间的共因失效时,用传统方法对系统进行可靠性分析会十分复杂繁琐。有鉴于此,提出一种基于二元决策图的考虑共因失效的多阶段任务系统可靠性分析方法。通过引入传播失效概率,建立各任务阶段扩展的故障树,并将其转化为系统BDD进行分析求解;给出多阶段任务系统的BDD算法以及系统可靠性函数的表达式,对系统进行可靠性评估。通过某柴油机冷却系统进行了可靠性分析验证,该方法能更好的处理部件间的阶段依赖性关系,而且对于共因失效问题的处理也更加简洁且计算简单易行。

The correlation of the same component or different parts of the phased mission system at different phases has important influence on the accuracy of the system reliability analysis results. The phased mission system reliability analysis is very complicated with the traditional method when the common cause failure （CCF） between the components is considered. Therefore, a reliability analysis method of phased-mission systems with common cause failure based on binary decision diagram （BDD） was presented in this paper. The extended fault tree of each mission stage was established by introducing the propagation failure probability, and was transformed into system BDD to analyze and solve. The BDD algorithm for phased mission system and the expression of system reliability function were given. The system reliability assessment can be carried on by using the presented method. A case of reliability analysis of a certain diesel engine cooling system was taken as an example. The method can better deal with the stage dependent relationship among components, and the processing of the common cause failure is more concise and easy to calculate.