Abstract: Stockpiling relief resources play a vital role in improving performance of responding potential disasters. Considering a relief organization facing multiple contingent disaster events, a two-stage delivery process model is developed to characterize relief materials' delivery after a disaster. The delivery process model proposes that relief organizations first deliver the stockpiling inventories after a disaster. The second delivery incorporating social donation and emergency purchasing is triggered only when the demand is backordered. A multi-product inventory model is proposed that aims to minimize the expected total costs when all demands incurred by an arbitrary disaster need to be fully satisfied. The optimal solution characterized by an implicit function is derived. Furthermore, the effect of the budget constraint is also investigated. A binary algorithm is established for solving the model. Numerical examples are employed to examine the model and algorithm.

Key words: humanitarian relief, relief materials, stockpiling, multi-product newsvendor model