Fuzzy Fault Tree Analysis Method And Its Application In Reliability Analysis Of Complex Systems Research

Fault tree analysis is an effective method for analyzing reliability and safety for complicated system. Traditional fault tree analysis is based on Boolean Algebra and Probability Theory. It is extensively used in many fields due to its success on solving probabilistic uncertainty.But in the large-scale complicated system, there are lots of fuzzy uncertainty. As a measure for managing uncertainty information, fuzzy mathematic theory can effectively dealt with reliability analysis problem for complicated system that probabilistic method can not do. So, it is theoretically and practically significant to combined FTA with fuzzy theory.The basic approach of fault tree analysis is introduced. The arithmetic operators of triangle fuzzy number, normal fuzzy number, and the fuzzy importance measure are studied in this paper.All fault phenomena probably to drive axle, especially the failure model of reducer, differential mechanism, and the bearing are analysed. Drive axle system fault tree based on drive axle abnormal sound as the top event is established. Fuzzy set and fuzzy number is used to substitute for precise probability of bottom event, and the fuzzy probability of the top event is calculated. From the result we can find that the bearing abrasion lapse is the critic event of the middle event M 2.Fault tree based on some fault of the aero engine as the top event is established. Fuzzy fault tree analysis method is used to calculate the fuzzy probability quantitatively. From the result we can find that the fan vane rupture is the critic event of the middle event M 5.