Availability modeling and behavioral analysis of a single unit system under preventive maintenance and degradation after complete failure using rpgt

In this paper Availability Modeling and Behavioral Analysis of a single unit system with Preventive Maintenance and Degradation after Complete Failure using Regenerative Point Graphical Technique (RPGT) is discussed. Initially the unit is working at full capacity which may have two type of failures, one is direct and second one is through partial failure mode. There is a single server (repairman) who inspects and repairs the unit as and when need arise. On partial failure (before complete failure) server repairs the unit which is perfect, but the unit and on complete failure the unit cannot be restored to its original capacity. If the server reports that unit is not repairable then it is replaced by a new one. Fuzzy concept is used to determine failure/working state of a unit. Taking failure rates exponential, repair rates general and taking into consideration various probabilities, a transition diagram of the system is developed to determine Primary circuits, Secondary circuits & Tertiary circuits and Base state. Problem is formulated and solved using RPGT. Repair and Failure are statistically independent. Expressions for systems parameters i.e. mean time to system failure, availability, and number of server visits and busy period of the server are evaluated to study the behavior of the system for steady state. Particular cases are taken to study the effect of failure and repair rates on mean time to system failure, availability, and expected number of server visits and busy period of the server. Profit optimization is also discussed. System behavior is discussed with the help of graphs and tables.