A Bi-Objective Supplier Selection Problem with Considering All-Unit Quantity Discount and Deteriorating Raw Materials

An increasing competition in global markets has caused the role of suppliers in supplying demands to gain much attention and that is why many researchers are interested in this area. In this paper, a bi-objective multi-period supplier selection problem with two echelons containing one manufacturer and several suppliers in a supply chain is considered. Suppliers offer discount for their sales and a fleet of various vehicles also delivers raw materials to manufacturer. Raw materials deterioration may occur in the suppliers’ location either during transportation or when stored in the warehouses. In this case, both minimizing the total cost and deterioration have caused the research to become much closer to the real world. In so doing, a mathematical model of an integer linear programing (ILP) was presented and then in order to evaluate the performance of the model, a numerical example was solved using an exact approach