This paper analyses a multi-period single-item repairable inventory system with stochastic new and warranty demands. We assume that newly-procured items are indistinguishable from items repaired from repairable warranty returns and new demand has higher priority than warranty demand within a period. Our model also captures the “repair loss” in repairing returns in each period. We formulate the problem by a dynamic programme, and prove that the optimal policy is completely defined by three period-dependent thresholds: the purchase-up-to level, the repair-up-to level, and the scrap-down-to level. Numerical results demonstrate the effectiveness of the optimal policy and show that our optimal strategy outperforms the repair-all strategy and no-repair strategy. Managerial insights are also generated.

本文分析了具有随机的新需求和保修需求的多周期单项可维修库存系统。我们假设新购买的物品与可修理的保修退货所修理的物品是无法区分的，并且在一段时间内新需求的优先级高于保修需求。我们的模型还记录了每个时期返修时的“维修损失”。我们通过动态程序制定问题，并证明最优策略完全由三个与周期相关的阈值定义：购买至水平，修复至水平和报废至水平。数值结果证明了最优策略的有效性，并表明我们的最优策略优于全部维修策略和不维修策略。还生成管理见解。