AN APPROXIMATE METHOD FOR NONREPAIRABLE SYSTEMS BASED ON OPPORTUNISTIC REPLACEMENT POLICY

An opportunistic replacement policy for a multi-unit system with various failure rates is developed. The objective function is to minimize the total maintenance cost due to preventive and failure replacement. Failure rate is used as replacement criterion for each unit. Units are replaced at failure or at a failure rate limit, L, whichever occurs first. A unit is also replaced at replacement time of another unit if its failure rate falls in a preventive replacement interval, (L - u, L). A solution method to obtain the value of L and u is presented. The solution procedure is demonstrated through an algorithm followed by a numerical example.