Quantification of Cut Sequence Set for Fault Tree Analysis

Abstract

A new evaluation method is presented that employs cut sequence set (CSS) to analyze fault trees. A cut sequence is a set of basic events that fail in a specific order that can induce top event. CSS is the aggregate of all the cut sequences in a fault tree. The paper continues its former researches on CSS and uses CSS, composed of sequential failure expressions (SFE), to represent the occurrence of top event. According to the time relationships among the events in each SFE, SFE can be evaluated by different multi-integration formulas, and then the occurrence probability of top event can be obtained by summing up all the evaluation results of SFE. Approximate approaches are also put forward to simplify computation. At last, an example is used to illustrate the applications of CSS quantification. CSS and its quantification provide a new and compact approach to evaluate fault trees.