Analysis of a System Reliability Model Subject to Degradation and Random Shocks

摘要

An attempt has been made to analyze a single-unit system subject to random shocks. The system may or may not be affected by the impact of shocks. There is a single server who visits the system immediately to conduct maintenance and repair of the unit. The unit undergoes for maintenance if it is affected by the impact of shocks. However, repair of the unit is done when it fails due to some other reasons. The unit works as new after maintenance while it becomes degraded after repair. The degraded unit may work for the system and is replaced by new one giving some replacement time if it is affected by the impact of shocks. Repair of the degraded unit is done if it fails due to the reasons other than shocks. The degraded unit is considered as degraded after repair. The time to failure of the unit and time to occurrence of a shock are exponentially distributed whereas the distributions of maintenance, repair and replacement times are taken as arbitrary with different probability density functions. The expressions for various reliability indices are derived in steady state using semi-Markov process and regenerative point technique. Giving particular values to various costs and parameters, the numerical results are obtained for mean time to system failure (MTSF), availability and profit to depict their graphical behavior with respect to shock rate.