COST ANALYSIS OF DEGRADED MACHINING SYSTEM WITH SPARE, COMMON CAUSE FAILURE AND OPERATING UNDER VARIABLE SERVICE RATE

摘要

In this Paper, we have studied the machining system with finite number of operating machines along with warm standby machines under the supervision of R heterogeneous repairmen. The repairmen are servicing with variable service rate. Whenever any machine fails, it is immediately replaced by available standby machine. Machine may also fail due to common cause. Once all the standbys are exhausted, the system has extra burden to share load of failures and it starts to work under degraded mode. It is assumed that, the time-to-failure and time-to-service of the machines follows the exponential distribution. Steady state probability is evaluated using recursive algorithm. We have developed a cost model to obtain the optimum number of repairmen and standbys maintaining the system availability at minimum specified level. Under optimum operating conditions, various system performance measures are evaluated and sensitivity analysis is also performed.