An improved method for risk evaluation in failure modes and effects analysis of aircraft engine rotor blades

Dempster–Shafer (D–S) evidence theory has been previously introduced in failure modes and effects analysis (FMEA) due to its effectiveness and flexibility in dealing with uncertain and subjective information. This study applies the modified D–S evidence theory to obtain the risk priority evaluation of failure modes by aggregating different opinions of experts which may be imprecise and uncertain. However, when experts give different and precise values of the risk evaluation factors, the basic belief assignments (BBAs) become highly conflicting evidence that cannot be fused by Dempster’s combination rule. In this paper, we propose an improved method to construct the basic belief assignments (BBAs) for risk evaluation. We illustrate several examples and use the modified method to deal with the risk priority evaluation of the failure modes of rotor blades of an aircraft engine. The results show that the proposed approach is more flexible and reasonable for real applications.