COST OPTIMIZATION OF MAINTENANCE SCHEDULING FOR A SYSTEM WITH ASSURED RELIABILITY

Systems which have to work at or below a maximum acceptable failure rate, should be maintained at predetermined points such that the failure rate does not exceed the acceptable level. As the system ages, the post-maintenance failure rate of the system drops to some newer one, unless the system has been replaced, but does not restore the system to the original state. This paper presents a branching algorithm with effective dominance rules that curtail the number of nodes created; this algorithm determines the number of maintenance interventions before each replacement in order to minimize the total cost over a finite time horizon. The model considers inflationary trends. A numerical example and computational experience demonstrate the algorithm. Most papers on maintenance problems have considered the maintenance interval as constant and increasing cost for successive maintenance for a system. This paper treats the maintenance cost as constant and successive simple-maintenance intervals as decreasing. Though our algorithm assumes that the cost/maintenance is constant, any increasing maintenance cost function could be incorporated. The optimum solutions depend on the: constant improvement factor first simple-maintenance point rate of increase in acquisition cost maintenance cost factor planning period.