Reliability analysis of CNC hydraulic system based on fuzzy fault tree

Taking account of the fuzziness associated with failure probability of hydraulic systems, a fuzzy fault tree is proposed in the paper by integrating the fuzzy set theory into the conventional fault tree analysis method. The triangular fuzzy numbers are utilized to qualify the fuzzy uncertainty of basic events in the construction of fuzzy fault tree. Moreover, the fuzzy importance measure of each basic event can also be computed. The proposed method is applied to a CNC hydraulic system to demonstrate its effectiveness, and it is able to provide industry practitioners a theoretical basis to facilitate the system reliability assessment, fault diagnosis, as well as maintenance decision.