Based on two substitute products, we study the inventory and contract coordination strategy of a three-echelon supply chain, which consists of two suppliers, a manufacturer and a retailer, under supply disruption and stochastic demand. We investigate the channel gross profit model of the centralized supply chain and obtain a unique optimal order quantity. Under a decentralized decision, we find that the commonly-used wholesale price contracts cannot coordinate the system. Then, we propose a buy-back contract and prove that this contract can more efficiently coordinate the system than the former. At last, we show that the integrated performance of the decentralized system can be maximized through choosing the buy-back parameter by the manufacturer and reveal that the effects of supply uncertainty and the substitution behavior of customers on the optimal decision by numerical examples.

In this paper, we investigate inventory and order strategies of a two-echelon supply chain, which is composed of two unreliable suppliers that are subject to random disruption. We develop the gross weighted profit benchmark model and the service level constrained model of the supply chain, respectively. We derive the retailer's optimal order quantity and analyze the retailer' optimal order policy and also obtain the analytical closed-form solutions. In addition, some numerical examples are provided to illustrate the effect of disruption time, disruption probability and fill rate on the optimal decisions and expected profit.