Vague Set Based FMEA Method for Risk Evaluation of Safety-Related Systems

Failure Mode and Effects Analysis is a structured method used to prioritize all possible vulnerable areas (failure modes) and address critical failure modes in a safety-related system. However, traditional FMEA method employed during risk evaluation has some critical drawbacks. Thus the main purpose of this study was to propose a vague set based FMEA method to recover those drawbacks as well as to evaluate and continuously improve risk of safety-related systems under vague and uncertain environment. The proposed method can contribute to address weaknesses of traditional FMEA method and provide a more reasonable representation of the real world problems under vague and uncertain environment. Besides, the proposed FMEA method can contribute to evaluate, prioritize and correct a safety-related system's individual failure modes and system's portfolio failure mode under vague and uncertain environment. Finally, a numerical case study was conducted to demonstrate that the proposed method is not only capable of addressing inherent drawbacks of traditional FMEA method but also is effective and efficient to be employed during continuous risk improvement process of a safety-related system.