safety risk assessment; using fuzzy failure mode and effect analysis and fault tree analysis

The failure mode and effects analysis (fmea) is a qualitative, inductive and effective method for detecting errors, faults, and failures in a system and fuzzy logic can improve that technique with more logical outputs. moreover, the fault tree analysis (fta) as a probabilistic risk assessment method is among the effective technique for calculating the probability of errors, faults, failures, reliability and safety integrity level (sil) verification resulting in certain events at higher levels. the fta also detects the main causes of events in complicated systems. although this technique appears to be time-consuming in systems with many diverse components, it is considered a powerful tool. in this paper, the fuzzy fmea analyzes the failure modes in a hypothetical system. after that, the process with the highest risk is selected as the input of an fta. according to the qualitative and quantitative analysis of ftas, a series of corrective actions will be proposed to reduce the failure probability.