Proposing a bi-objective model for the problem of designing a resilient supply chain network of pharmaceutical-health relief items under disruption conditions by considering lateral transshipment

In this paper, a bi-objective mathematical model is presented for the problem of designing a resilient supply chain network of pharmaceutical-health relief items in the condition of disruption, taking into account the possibility of lateral transshipment. The first objective function of the model aims to minimize the total costs and considering the importance of effective and efficient distribution to meet the demand of patients in a humanitarian supply chain network, the second objective function is minimizing the total time required to deliver relief items to the demand points. Given the inherent uncertainty associated with the occurrence of a crisis and its impact on the supply chain network, a scenario-based robust optimization method is used to address the problem. The model is solved using the epsilon constraint method for small sizes and the NSGA-II meta-heuristic algorithm for larger sizes. In addition, the model is solved with and without lateral transshipment, and the results are compared and analyzed. The findings indicate that lateral transshipment can improve the performance of the supply chain and reduce the level of shortage.