Abstract: Aiming at the risk priority numbers of different failure modes being equal and the criticality of the fault modes changing greatly due to the tiny change of the risk parameters, a method of the failure modes analysis based on the weighted evidence theory is proposed from the perspective of the methodology of dealing with the uncertainty problem. The method qualifies the epistemic uncertainty existing in the expert evaluation of the risk parameters into the basic belief assignment and expert attribute weight respectively, and the information propagation and processing of the epistemic uncertainty is solved, and the ordered arrangement of the criticality analysis of the fault modes is eventually achieved. The practicability and effectiveness of the proposed method are verified by the case analysis and comparison with the existing research results.

Key words: weighted evidence theory, failure modes effect and criticality analysis, epistemic uncertainty, risk priority number, electronic system