A location-allocation model in the multi-level supply chain with multi-objective evolutionary approach

In the current competitive conditions, all the manufacturers’ efforts are focused on increasing the customer satisfaction as well as reducing the production and delivery costs; thus, there is an increasing concentration on the structure and principles of supply chain (SC). Accordingly, the present research investigated simultaneous optimization of the total costs of a chain and customer satisfaction. The basic innovation of the present research is in the development of the hierarchical location problem of factories and warehouses in a four-level SC with multi-objective approach as well as the use of the multi-objective evolutionary metaheuristic algorithms. The main features of the resulting developed model would include determination of the number and location of the required factories, flow of the raw material from suppliers to factories, determination of the number and location of the distribution centers, flow of the material from factories to distribution centers, and finally allocation of the customers to distribution centers. In order to obtain optimal solutions of the model, a multi-objective hybrid particle swarm algorithm (MOHPSO) was presented; then, to assess performance of the algorithm, its results were compared with those of the NSGA-II algorithm. The numerical results showed that this algorithm had acceptable performance in terms of time and solution quality. On this basis, a real case study was implemented and analyzed for supplying the mountain bikes with the proposed algorithm.