مطالعه‌اي در الگوهاي بهينه تعمير و نگهداري سيستم‌هاي چند مولفه‌اي

Most of the vital systems and advanced equipment that are used in human life today become old and deteriorate with the passage of time or may fail due to destructive shocks. Like airplanes, submarines, military systems, etc., it is very important to prevent failure during actual operation because it can be dangerous or catastrophic, so maintenance is essential. Maintenance of systems and implementation of optimal maintenance strategies is effective in improving system reliability and preventing system failures, and therefore reduces maintenance costs of deteriorating systems. In this thesis, we will first review the basics and basic concepts of system reliability, and then we will review the preventive maintenance policies of systems and examine the maintenance patterns of complex systems. We also introduce multi-component maintenance models exposed to shock and aging and present new and general methods based on the time and number of shocks and in situations where the system fails due to aging and deterioration over time. The goal is to obtain the cost function and minimize it. Since the structure of the cost function depends on the structure of the system and nowadays the systems have a complex structure, the results presented in the literature related to the optimal maintenance of systems are based on a concept called signature and t-signature. This concept makes it possible to write the reliability function of a complex system as a composite of the ordered lifetime reliability function of its components. At the end, after introducing the models using numerical examples, the presented methods are eva‎luated. As a result, by applying timely preventive maintenance, the cost function is optimized

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