Developing a multi-objective mathematical model of green closed-loop supply chain In terms of selling returned products using the Epsilon-constraint method approach

Currently, rapid economic change and increasing competitive market pressure are pushing organizations to focus on making supply chain operations more efficient and effective. Proper design and efficiency of logistics networks as part of supply chain planning, in addition to creating a sustainable competitive advantage, increases customer satisfaction and provides the opportunity to meet their needs, which is why the decisions related to the design of these networks are of great importance. Enjoy. Therefore, in this study, the design of a closed-loop logistics network to reduce pollution and environmental pollution using the Bertsimas and wire stabilization method was presented. The mathematical model to be presented in this research was presented by considering the objectives of minimizing transportation costs, minimizing the time of receiving raw materials from the supplier and minimizing the time of product return from the customer to the separation center. Due to the strategic nature of the closed-loop supply chain, which with the approximate solution space causes a lot of costs to be delivered to the system to increase the accuracy of the answers of the mathematical model and application of this goal in this study It is used to reduce the computational time of the model, the results obtained with high accuracy. On the other hand, because the operational logic of solving Lagrange release is based on a single-objective model, first multi-objective mathematical model with Augmented Epsilon-Constraint The target was converted and then the Lagrange release algorithm was implemented on it.