故障树分析的等效失效概率计算方法

在故障树分析中，系统的失效概率及部件重要度函数并不能全面考虑所有部件所有状态对系统可靠性的影响，为弥补这一不足，提出等效失效概率的概念及其计算方法。利用概率分解法来分析部件及系统所有的存在状态，采用马尔可夫链法及概率论知识计算系统的期望工作次数，进而获得等效失效概率。应用中表明，等效失效概率能够完全考虑所有部件关键状态及非关键状态对系统可靠性的影响。在干系统失效概率相同的情况下，可以利用等效失效概率来比较不同系统的可靠度。该方法是对目前部件重要度函数的扩展，具有一定的实用价值。

EQUIVALENT FAILURE PROBABILITY CALCULATION METHOD FOR FAULT TREE ANALYSIS

In fault tree analysis,the system failure probability and the component importance measures cannot totally include the contribution of all the component existing states to system reliability.Hence,an equivalent failure probability concept and calculation method is proposed.First,the system existing states are analyzed by probability decomposition method.Markov chain method and the expectation theory are used to calculate the expected number of working circle.And the equivalent failure probability is fmally attained.Analysis shows that, equivalent failure probability not only includes the contribution of the critical states of component to system reliability,but also considers the non critical states of component,the equivalent failure probability may compare the relative reliability when different systems have the same failure probability,and the concept of equivalent failure probability is an important exten- sion of current component importance measures and is useful for reliability design.