a New Method for Fmeca Based on Fuzzy Theory and Expert System

Failure Mode Effects and Criticality Analysis (FMECA) is one of most widely used methods in modern engineering system to investigate potential failure modes and its severity upon the system. FMECA evaluates criticality and severity of each failure mode and visualize the risk level matrix putting those indices to column and row variable respectively. Generally, those indices are determined subjectively by experts and operators. However, this process has no choice but to include uncertainty. In this paper, a method for eliciting expert opinions considering its uncertainty is proposed to evaluate the criticality and severity. In addition, a fuzzy expert system is constructed in order to determine the crisp value of risk level for each failure mode. Finally, an illustrative example system is analyzed in the case study. The results are worth considering in deciding the proper policies for each component of the system.