A Mixed Integer Nonlinear Programming for Facility Layout Problem with Maintenance Constraints

Document Type: Research Paper


Assistant Professor, Department of Industrial Engineering, Arak University, Arak, Iran


The facility layout problem (FLP) is a well-known optimization problem that seeks to arrange the layout of production units or facilities generally towards less cost and considering some adjacency factor between the facilities. The adjacency factor mainly represents the material handling costs. In this research, a novel multi-objective mixed integer nonlinear programming (MINLP) model for the single-floor facility layout problem is developed. The model, unlike the current literature, considers some maintenance measures in addition to the classical adjacency factor. Firstly, some facilities need a certain amount of maintenance space around them. If this space is violated, some penalty would apply. Secondly, some facilities could have emergency maintenance requirements for which easy access from the entrance edges is necessary. This accessibility measure is optimized in the model. The validity of the proposed MINLP model is analyzed via simulation. The results show that if material handling costs are minimized, the maintenance measures will deviate approximately 100% of their optimal values. Moreover, if maintenance measures are optimized, the material handling cost will deviate around 50% of its optimal value. Both, classic and maintenance related measures show more sensitivity in dense and crowded production environments.