On modeling, discrete-event simulation, and optimization of spine layouts

Today, discrete-event simulation (DES) has proven to be an essential tool for designing complex high-performance and cost-effective manufacturing systems. However, a significant challenge still lies in modeling specialized system layouts such as the spine layout, which is characterized by a central aisle flanked by corridors with workstations and served by an overhead automated material handling system. While the spine layout has demonstrated to be suitable in industries with complex operational requirements, current DES tools still lack dedicated modeling constructs for this type of layout and its characteristic properties, making the modeling process time-consuming and error-prone. To overcome the current situation, we develop a basic formalism that captures essential properties of spine layouts and defines their inherent discrete-event simulation semantics. Furthermore, we elaborate on the layout optimization as well as the job routing and scheduling problems, which designers need to solve eventually. Finally, we provide a prototypical implementation of the formalism based on the Python programming language and the Salabim discrete-event simulation library for demonstrating the capabilities of the approach, while leaving the optimization issues open for future work.