A multi-period vehicle routing problem in a reverse logistics system with recovery options

Reverse Logistics with Recovery Options studies have grown in recent times as the need for the preservation of our environment becomes very important nowadays and corporations must address this situation while maintaining profitable business operations. In addition to reverse logistics with recovery options, Vehicle Routing with time windows was also considered in this study due to the high amount of cost it makes up in distribution systems such as supply chains and logistics operations. Vehicle Routing can contribute to up to 30% of the total system cost of distribution systems. This study was aimed at integrating vehicle routing to a reverse logistics system with recovery options which incorporates vehicle time window and carrying costs that would enable a company to efficiently handle returned product flows and evaluate whether the use of these products would enable the company to minimize their total system cost in satisfying the demand. The study deals with a three-echelon network consisting of collection centers, warehouses, and factory or repair center for a single product considering only the reverse logistics activities. A deterministic model was created and translated to the General Algebraic Modeling Systems (GAMS) language and then validation was done to verify the model\u27s behavior. Design of Experiments (DOE) was used to identify which factors significantly affect the system response then these factors were used in the Response Surface Methodology (RSM) to analyze the behavior of the relationships of the variables in the system. Based on the results of the sensitivity analysis or in the use of RSM, it was found that the modeler would be more capable of minimizing the total system cost if vehicle routing was integrated in a reverse logistics system with recovery options