Fuzzy repairable reliability based on fuzzy gert

Military equipment and weapon systems have become more advanced, precise and complex. Requirements of threat and readiness have been raised. Nowadays, the advance of weapon systems and their logistic support places the emphasis on the life cycle in the initial design. However, reliability analysis is the main work of logistic engineering. Its aim is to develop the best design for weapon systems operating in a special operation environment. Accordingly, there are many factors to consider in the reliability of weapon systems. Generally, those factors are of an uncertain nature. Traditionally, we use probability theory to treat the reliability of a weapon system. The probabilistic approach can only represent the randomness of a success or failure event, and requires complete data and predetermined conditions. Fuzzy sets theory can efficiently treat the above characteristics and shortcomings. Therefore we will propose a method and technology of fuzzy system reliability to solve the above problems.In this paper we first formulate the building membership functions of component reliability based on the α-cut method. Secondly, when the membership functions of the components are built, we can propose some fuzzy mathematic models for solving fuzzy system reliability. Different models and approaches have been studied and proposed in this research. In an unrepairable system, we have built two methods. In a repairable system, we will propose a fuzzy GERT (graphical evaluation and review technique) method to calculate the fuzzy reliability. For a simple and efficient computation, we have developed systematic and practical algorithms to calculate and analyze fuzzy system reliability. We have also presented an example of a military operation mission to demonstrate our proposed methods.