Presenting a Model and Heuristic Algorithm for Two-Echelon Location-Routing Problem under Uncertainty Considering the Simultaneous Pickup and Delivery

In this paper, we address a variant of the Location-Routing Problem (LRP), namely the Two-echelon location routing problem with simultaneous pickup and delivery (2E-LRPSPD). The purpose of location-routing problem is to determine the optimal number and locations of depots while allocating customers to depots and determining number of optimal vehicle and vehicle routes to visit all customers. The objective is to minimize both the cost of open depots and the total cost of the routes. In this paper customer’s demand is uncertain with discrete values in fuzzy trapezoidal numbers. Applying this approach can result in making an appropriate decision of service level for customers by experts while accounting for considering the system’s costs. We propose an adaptive large neighborhood search for the Two-Echelon Location-Routing Problem with simultaneous pickup and delivery (2ELRPSPD). Computational experiments conducted on several sets of instances from the literature show that our algorithm outperforms existing solution methods for the 2E-LRP and a new data set is also generated for our presented model which contains both pickup and delivery demands and Computational results are reported. The results imply the efficiency of the proposed algorithm in finding better solution in comparison to the ones obtained via other algorithms existing in the literature of location routing problem.