Risk assessment in system FMEA combining fuzzy weighted average with fuzzy decision-making trial and evaluation laboratory

Failure mode and effects analysis (FMEA) is a risk assessment tool that mitigates potential failures in products, processes or systems before they occur. Although many industries use the traditional FMEA technique, it has been criticised for having several setbacks. First, the current FMEA determines the risk priorities of failure modes by using risk priority numbers (RPNs), which require the risk factors, occurrence (O), severity (S) and detection (D), to be evaluated in crisp values. Second, the conventional RPN method has not considered the indirect relations between components of a system and is insufficient for complex systems with many subsystems or components. Therefore, a new risk assessment methodology combining fuzzy weighted average with fuzzy decision-making trial and evaluation laboratory (fuzzy DEMATEL) is proposed in this article to rank the risk of failures in system FMEA. The new method can address some of the inherent limitations of the traditional FMEA. Also, an application to the thin film transistor liquid crystal display (TFT-LCD) product is presented to demonstrate the proposed FMEA. By comparing with the listed approaches, the results show that the proposed method is a suitable and effective method for prioritisation of failures in system FMEA.