EXTENDED OPTIMAL REPLACEMENT MODEL WITH RANDOM MINIMAL REPAIR COSTS

This paper proposes a generalized replacement policy where a system ha s two types of failures and is replaced at the n-th type I failure (mi nor failure) or first type II failure (catastrophic failure) or at age T, whichever occurs first. Type I and type II failure are age-depende nt. Type I failures are removed by minimal repairs. The cost of the mi nimal repair of the system at age z depends on the random part C(z) an d the deterministic part c(z). The expected cost rate is obtained. The optimal n and optimal T* which would minimize the cost rate are disc ussed. Various special cases are considered. Finally, a numerical exam ple is given.