Introducing a bi-level model to optimise the distribution network design and assembly line balancing

This article investigates how to simultaneously optimise both strategic and tactical decisions in the supply chain network design. For this purpose, a bi-level model was introduced to optimise the design of supply chain network and assembly line balancing. In this research supply chain network design problem is considered as a strategic decision in the upper-level model, while the lower-level model contains the assembly line balancing as a tactical decision. The three-level considered supply chain includes factories, assembly lines and customers. The factories produce the raw material needed for assembly lines to produce final products. The assembly lines produce final products and deliver them to customers to cover their demand. Also, these assembly lines balance their line simultaneously. The operation time for assembly line, the cost of operation and customer's demand were considered as uncertain variables. Finally, this model was run on some data to evaluate its capability.