Stock-out policies of a spare-parts warehouse for a multi-item repairable system
研究了有限容量备件仓库在多部件可修系统中的最优补货与缺货策略，通过矩阵几何方法求解最小化总成本的阈值，并比较了冷备用与紧急供应两种缺货策略的效果。
In industrial settings, the management of spare-parts inventory can have a significant impact on the system's reliability and profitability. In this paper, we provide a framework that jointly optimises reliability of a multi-item system and the management of an accompanying spare-parts warehouse (SPW) with a finite capacity. Consider a system with N items that operate in parallel and have random life spans; when an item breaks, it is replaced by a spare part (if available) with no time. The SPW is managed according to a continuous-review (S,s) policy. That is, when the number of spare parts drops to level 0≤s<S, an order is placed to replenish the warehouse to level S after a random lead time. When a spare part is unavailable, the company chooses between two stockout policies: a cold standby policy or an emergency supply policy. Using the matrix-geometric method for phase-type distributions, we derive the optimal thresholds minimising the expected discounted total cost (including replacement, replenishment, maintenance, downtime, and emergency supply costs). Using a numerical study, we compare the policies and provide managerial insights. For example, we show that an emergency supply policy may yield a significant cost reduction, particularly for high maintenance cost and long lead times.