Bi-Objective Optimization of Vendor Managed Inventory Problem in a Mult Echelon Green Supply Chain

Integrating decisions in the supply chain is a challenge for producers who intend to optimize their supply chain costs. Vendor managed inventory (VMI) is one of the popular strategies for integrated supply chain management. In this strategy, customers provide their information to the vendor, and the vendor uses this information to manage their inventory and decide on the order quantity and delivery schedules. In this study, a three-tier green supply chain consisting of multi-retailers, multi-vendors with backorders is considered. The total cost of green supply chain is minimized and system reliability for manufactured goods is maximized by considering the constraints. The meta-heuristic methods of GA, SA and a combination of SA-GA are used to solve the model. Taguchi method was used to increase the efficiency of the algorithms. After performing the algorithms for problems of different sizes, the results were compared with respect to the efficiency of the algorithms. The obtained results suggest that the efficiency of the SA-GA is better than other algorithms. Finally, since the model is multi-objective, Pareto optimal solutions are analyzed.