Optimization of multi-product dynamicrouting model for vehicles after disaster,with justifiability of demand shortage

Regarding the five-fold increase in unexpected accidents in the past decade and the increase in its human and financiallosses, the relief supply chain has always been considered by humanitarian organizations as a suitablesolution to reduce the cost of disaster. One of the most important fields in this area is the routing of vehicles, whichhas an important role in improving service to the injured. Undoubtedly, the selection of inappropriate routes forvehicles has a negative effect on timely and suitable relief operations. Several studies have been conducted in thisregard, the models presented by them are often periodic and single-product, and the demand shortage of sheltersis not permitted. In this research, a multi-product relief chain network has been proposed, including three mainareas: vehicle maintenance centers, distribution centers for relief supply chains and shelters. The proposed mathematicalmodel, with a goal to maximizing the supplied demand, by a minimum of vehicle and time, addresses thedynamically routing of vehicles. In the event of excess demand, at the end of the operational periods, the amountof unsupplied demand for each type of product will also be determined in terms of each shelter. In order to validatethe proposed model, information of the 4th district of Tehran province, which is published in the basic papers, isutilized and has been solved by GAMS software. The results of the numerical solution of the model showed thatall relief operations are in order to maximize the supply of demand in the shortest time. Also, the amount of unsupplieddemand for shelters, the amount and type of goods carried, and the route of each vehicle’s movement in eachperiod, are other outcomes of the model