Scenario-based redesigning of a relief supply-chain network by considering humanitarian constraints, triage, and volunteers’ help

In disaster management problems, supply and distribution chains of relief commodities have been one of the most critical parts of planning for both pre- and post-disaster phases. Providing relief items (medical supplies) for injured people can directly affect the vitality rate, and this would perfectly explain the necessity of implementing such practical studies in this field. Thus, a scenario-based, multi-period, multi-objective, two-stage, location-allocation model for providing relief commodities to demand points in an uncertain environment is proposed in this study. Humanitarian constraints (equitizing the number of distributed items and the service time as well as prioritizing areas in receiving the commodities) are also considered in the model to make it closer to reality. Such other practical contributions as redesigning the supply chain and addressing volunteers’ help in the supply and distribution processes are formulated as well. Moreover, using the triage concept for distributing vital items is presented for the first time in this study. The proposed non-linear model is initially linearized and then solved by applying the epsilon-constraint technique. Due to the NP-Hardness property of the model, an NSGA-II and a hybrid algorithm are also presented to solve larger-sized instances. Solving numerical examples and conducting sensitivity analysis verify the applicability and efficiency of the proposed model as well as the solution algorithms and provide some managerial insights to improve the performance of the relief logistics.