Abstract:

Due to simply multiplication when the risk priority numbers are calculated in traditional failure mode and effects analysis (FMEA), the risk evaluation indicators are inaccurate. And the slight changes of attribute values, caused by subjective factors, have a great impact on the final result. The fuzzy technique for order preference by similarity to an ideal solution (TOPSIS) theory is introduced into the occurrence, severity and detection degree to conduct a risk assessment, and after defuzzification and normalization, the weighted judgment matrix is constructed. Meanwhile, the positive and negative ideal solutions are determined by the technique for sequencing by approximate ideal solution, and the risk level of each fault mode is ranked according to the size of relative closeness. Compared with the traditional failure mode and effects analysis, the effectiveness and practicability of this method are verified, which can provide effective reference to the risk level assessment for other components of aircraft power system.

Key words: aircraft power system, risk assessment, failure mode and effects analysis (FMEA), technique for order preference by similarity to an ideal solution (TOPSIS)