ABSTRACT
Basic concepts and methods of the fuzzy fault tree were proposed in 1980s (Tanaka et al.1983, Furuta 1984). At present, the study of the fuzzy fault tree is almost focused on algorithm and the integrated theory systems have not been established and verified in practice (Singer 1999). A fuzzy set is introduced in this paper and the failure probability of basic events is replaced by the fuzzy failure probability. A triangular fuzzy number is introduced to represent the failure probability of a basic event and the fuzzy failure probability of a top event is obtained by fuzzy number operation. Measures to reduce the cutterhead failure possibility of the EPB shield are verified by analyzing the importance of basic events.
