A Multi-Size Compartment Vehicle Routing Problem for Multi-Product Distribution: Models and Solution Procedures

This paper presents a Multi-Size Compartment Vehicle Routing Problem with Split Pattern (MC-VRP-SP). This MC-VRP-SP focuses on the delivery of multiple types of liquid products from depot to customers. The main objective is to minimize the total traveling cost. Multiple types of fluid product are loaded to the vehicles having several capacities with non-identical capacity of compartments. Then, two mathematical models are proposed to represent this MC-VRP-SP. Since the order quantity may be over the capacity of compartment, the splitting of order is needed. The original customers demand is split according to the predetermined patterns so that it can be loaded to compartments appropriately. However, the split demands must be delivered by the same truck and one compartment can support only a single split demand. The optimization approach is utilized to solve these mathematical models within the limited computational time. A homogeneous and heterogeneous fleet of multi-compartment trucks are considered in the numerical experiment. The results from numerical examples show that the optimization approach can yield us the optimal solution only in small-scale problem. For large-scale problem, the optimization approach can determine only the feasible solutions. Thus, the local search so called 2-opt is employed to make an improvement on solution of the large-scale problem. Moreover, a saving algorithm is utilized to separate the customers into clusters. Then each cluster is solved separately by CPLEX. The results show that this clustering can significantly improve the solutions on the large-scale problem.