AMWRPN: Ambiguity Measure Weighted Risk Priority Number Model for Failure Mode and Effects Analysis

The relative importance of each risk factor in failure mode and effects analysis (FMEA) should be addressed properly. Intuitively, in the assessments coming from the FEMA experts, there exists a potential judgement on which risk factor has a higher weight for the FMEA item. Based on this cognition and perspective, a new ambiguity measure weighted risk priority number (AMWRPN) for FMEA is proposed. AMWRPN takes into consideration of the relative weight of different risk factors by measuring the ambiguity degree of the experts' assessments. If the assessment of an expert has a certain belief on the judgement, then the relative importance of the corresponding risk factor will be higher than the uncertain one; and vice versa. The ambiguity measure (AM) in the framework of the Dempster-Shafer evidence theory (DST) has been used to construct the exponential weight of each risk factor in AMWRPN. In comparison with the weight factor basing on fuzzy sets theory or other theories in the DST framework, the AM-based weight factor for uncertainty measure of the subjective assessment ensures the internal coordination of the proposed method. An application of the proposed method in aircraft turbine rotor blade verifies the effectiveness of the new risk priority number model.