AVAILABILITY, MTTF AND COST-ANALYSIS OF A 3-STATE PARALLEL REDUNDANT MULTICOMPONENT SYSTEM UNDER CRITICAL HUMAN FAILURES

This paper deals with the availability, MTTF and the cost analysis of a single server complex system consisting of two classes A and B with three possible states, viz. good, degraded, failed and suffers two types of failure, viz. unit failure and failure due to critical human errors. Sub-system A has two dissimilar units arranged in parallel whereas sub-system B has three nonidentical units arranged in series. Failure and repair times have exponential and general distributions respectively. There is only one repair facility when the system is in failed state due to failure of sub-system B. Several parameters of interest are obtained using the supplementary variable method. A numerical example has been appended. Five graphs have also been given in the end.