An Integrated Multi-Objective Mathematical Model to Select Suppliers in Green Supply Chains

Compatibility with the environment is one of the important factors in designing a supply chain system, which is also called the “green supply chain”. Similar to the supply chain, green suppliers are very important players in the green supply chain. This paper studies both selection of suppliers and optimal order allocation to them. Despite previous studies, we consider both strategic and operational decisions into the problem. Firstly, we investigate the relevant criteria in selecting suppliers, and assign appropriate weights to suppliers. Then, we apply the fuzzy TOPSIS technique to asses and rank the suppliers. Finally, we investigate optimal allocation of order to the suppliers. For this reason, a two-objective mathematical model is developed. To solve the model, “weighting” and “ɛ-constraint” methods will be investigated, followed by a sensibility analysis to study the changes in the problem’s parameters. The proposed approach is important because it models the strategic and operational decision simultaneously.