关键词: 库存策略, 供应链中断, 订货模型, 更新报酬

Abstract: Under the assumption that the durations of the available or disruption periods at the warehouse are mutually independent exponential distributions，firstly both the expected time length and cost of one cycle are developed for the warehouse’ stock.Secondly the long-run average cost model is established based on renewal reward theorems，so the optimal order quantity and optimal expected cost models are obtained.According to the analysis it is verified that the models are an extension of classic economic order quantity models and the optimal lot sizes are always less than the ones in a corresponding reliable case.Finally computational results show that the average operating cost of the unreliable warehouse is decreased significantly via effective inventory management，especially when the disruptions taken place at the warehouse are frequent.

Key words: inventory policy, supply chain disruption, order model, renewal reward