Dynamic fault tree analysis using fuzzy L-U bounds failure distributions

摘要

One of the most important methods in reliability analysis is Fault Tree Analysis that over time it has been extended into the more versatile method of Dynamic Fault Tree (DFT) Analysis. In most cases, exact evaluation of system reliability using fault tree due to component limited data especially owning to failure rates, is difficult. In this paper, the Fuzzy Time-To-Failure (FTTF) model based on Fuzzy Lower and Upper (L-U) bounds is developed to evaluate the reliability of system and solve aforementioned problems. This process completed by proposed Fuzzy Monte Carlo Simulation (FMCS) throughout the preferred operational time and uses the actual types of fuzzy failure distribution. FMCS is done based on Lower-Upper bounds for each event failure rates. Using fuzzy arithmetic, events FTTF are generated, and then, the Top Event failure curve and the reliability profile of the system are evaluated. The results show that the proposed method not only is feasible and powerful but can also accurate more than the other probabilistic and Possibilistic techniques. Finally, this model is implemented in an Emergency Detection System (EDS) which is a useful system in aerospace and space applications.