This paper extends the modified block-replacement policy (MBRP) of Berg & Epstein (1976) in two ways; we consider: 1) a discrete time framework which allows the use of any discrete lifetime distribution, and 2) multi-component systems. Both of these extensions increase the practical value of the MBRP. In MBRP, components are replaced immediately on failure, and preventive maintenance (PM) is performed at regular intervals. During PM every component whose age is greater than a fixed threshold age is replaced. Unlike many models for multicomponent systems, this policy is structured. In both the standard block-replacement policy (SBRP) and MBRP, PM is performed at regular intervals and so can be planned in advance. However MBRP results in a lower average cost-rate by replacing components selectively during PM. Our results show how successful the MBRP is in this respect by comparing its cost with the costs of good, but difficult to compute & implement, agebased PM policies. This paper shows that MBRP is appreciably better than SBRP and only slightly poorer than the ARP for multi-component systems with a variety of lifetime distributions and a range of cost parameters. In most of our examples the MBRP bridges more than 2/3 of the gap between the minimum average cost of the ARP & SBRP. Compared to the ARP, the MBRP is more convenient because PM can be planned in advance, tracking the ages of components is unnecessary and, for multi-component systems, the optimal MBRP is easier to compute & characterize. The average cost-rate for a MBRP is not sensitive to small changes in the interval length or the threshold value, so the benefits of MBRP can be realized almost entirely by the proposed heuristic policy. In practice this heuristic is adequate. Where SBRP is already used, this heuristic is especially attractive because the interval between applications of PM does not change.

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doi.org/10.1109/24.488920, hdl.handle.net/1765/73419
I E E E Transactions on Reliability
Erasmus School of Economics

Archibald, T., & Dekker, R. (1996). Modified block-replacement for multiple-component systems. I E E E Transactions on Reliability, 45(1), 75–83. doi:10.1109/24.488920