چكيده به لاتين
The green quality and warranty period of products are two major factors which affect consumers’ purchasing behavior. In this study, a two-echelon supply chain consists of a manufacturer and two competing retailers is investegated in which two different applications of after-sales services (i.e. warranty service) are considered. In the first model, the manufacturer aims to release a new substitutable green product in addition to the conventional non-green product and determine the green quality level of the new product. On the other side, the retailers compete with each other on the warranty period offered to the consumers for the green product. Firstly, the optimal decisions of the supply chain members are evaluated under (1) Cournot, (2) Collusion, and (3) Stackelberg structures. Afterward, a new risk compensating wholesale price contract is developed which is capable of coordinating decisions through different echelons of the supply chain. In this model, warranty is used as a marketing strategy and a sign for guaranteeing the quality of the new product produced by a car manufacturing company. By applying the proposed coordination model, the manager of the company can efficiently use this marketing strategy. In the second model, after-sales service is considered as a strategy for increasing the collection rate of the used products in a closed-loop supply chain. In fact, the aim of this model is to find a solution for the problem which an auto spare parts company faces. Accordingly, in this study, using warranty service as a strategy for collecting the spare parts as well as providing economic incentives by the company for its agents and applying a coordination model (through an expense-sharing contract) for finding the equilibrium solutions for the decision variables, are proposed for solving the problem. The results of the first model indicated that by using warranty as a marketing strategy and coordinating green qualtity and competitive warranty period decisions, not only the economic performance of the supply chain is improved in comparison with the decentralized model, but also the manufacturer increases the green quality level of the new product and the retailers provide longer warranty period for this product. These are in turn beneficial for the customers. Moreover, the environmental performance of the supply chain will be improved. Based on the observations in the second model, by applying warranty as a collection strategy, providing economic incentives and applying the proposed coordination model by the manager of the supply chain, not only the economic performance of the supply chain is improved but also its social and environmental performances are improved. Providing economic incentives by the manufacturer for the service agents causes them to provide better qualified services. Moreover, a larger amount of the used products will be collected. The results indicated that, when there is intense competition or providing services are too costly, applying the proposed expense-sharing contract will be benificial for enhancing the supply chain performance.
