A Method of Disjoint Quantitative Analysis for Dynamic Fault Tree

Dynamic fault tree is widely used in the reliability analysis of dynamic system, where the cut sequence describes the failure mode of the system. Though the disjoint of cut sequence set can simplify the solving of top event failure probability, there is no available method of disjoint quantitative analysis that applies to the dynamic fault tree for the moment. A method of disjoint quantitative analysis is proposed. The conception of extended cut sequence is brought forward, which incorporates with the temporal logic based on cut sequence and has more representative capabilities than other similar conceptions. The extended cut sequence set is splited into the disjoint extended cut sequence set according to the basic event set and the temporal constraint set. The disjoint extended cut sequence is then transformed into the standard extended cut sequence. Conflict detection, reduction of temporal restriction set and topological sort of basic event set for each cut item, are carried out to quantitatively analyze each standard extended cut sequence. The involved algorithms and their complexities are particularly proved and analyzed. Finally this method is applied to a case and compared to the MCS method based on the rule of inclusion-exclusion. The result shows that the time cost of this method is greatly decreased. This method can obtain the disjoint extended cut sequence set of dynamic fault tree，and decrease the time cost of the solving.