Abstract

COST AND BENEFIT ANALYSIS OF TWO-OUT OF-THREE UNITS REDUNDANT SYSTEM INVOLVING COMMON CAUSE FAILURE AND PREVENTIVE MAINTENANCE

Hamza Abubakar, Aminu Rabi’u & Ahmed Madugu

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Abstract Many authors have studied the cost benefit analysis of two units cold standby redundant systems with two types of unit failure, but no attention was paid on the cost benefit analysis of two-out of-three units cold standby systems involving common cause failure and preventive maintenance. In this paper one may wish to realize how failure affect the mean time to system failure (MTSF), the steady-state availability , the profit function and even the effect of failure to the busy period of repairman as well, using Kolmogorov’s forward equations method. Some particular cases have also been discussed graphically. The result showed that the MTSF, the system availability and the profit functions are decreasing with the increase of failure rate, but there is an increase of the busy period of repair man as a result of an increase of the failure rate. The result indicated that an increase in failure rate to the proposed system result in a Profit decrease. Nevertheless, if the increase in failure rate is terminated and replaced with repair rate, it would earn maximum Profit to the system.

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