Importance Analysis of Fault Tree in Probabilistic Safety Assessment and Reliability Estimation

Abstract

Both the critical importance index of fault tree analysis(FTA) in probability safety assessment and global sensitivity index in reliability estimation can be employed to determine the important input variables. What are the differences and connections between the two kinds of importance degree? Firstly, the qualitative and quantitative analysis of fault tree in probabilistic safety assessment are introduced, and then the failure probability and global sensitivity analysis of fault tree in reliability estimation are presented. Finally, several FTAs of aircraft systems are analyzed and compared. It is found that the failure probabilities are basically consistent, but the important rank of basic events will be different for the randomness of the basic events' probabilities. And the influence of the distribution types and parameters on the global sensitivity index should be not negligible.

Keywords

• fault tree analysis
• probabilistic safety assessment
• reliability estimation
• failure probability
• critical importance
• global sensitivity