A Multiobjective Optimization Approach for Integrated Production Planning, Location-Allocation, and Routing in Three-Echelon Supply Chains

The focus of many researchers in the operations research field has been on supply chain design problems during past decades. Previous works have widely investigated production-inventory planning, vehicle routing, and location-allocation problems. This paper aims to consider these problems simultaneously and present a new integrated production planning-location-routing problem for a three-echelon supply chain, considering several real-world assumptions. The studied supply chain includes multiple production centers, distribution centers, and customers. The distribution centers use a set of non-homogeneous vehicles to deliver the products to the customers. Several features, such as regular and overtime production, production reliability, time-window constraints, and capacity constraints, are incorporated to provide a more realistic problem. The bi-objective model aims to determine the optimal location, allocation, production, and routing decisions to optimize the total cost and servicing time objective functions. Concerning problem’s complexity, the non-dominated sorting genetic algorithm-II (NSGA-II) is designed and implemented as a solution approach. The results reveal that this algorithm can solve the model in an acceptable time interval. In addition, the results demonstrate that the NSGA-II algorithm is reliable in finding solutions, and there is no significant difference between the average solution and the best solution of the algorithm in several runs.