An Exact Area Linearization Method for Unequal Areas Facility Layout Problem

Document Type : Original Article


department of Industrial Engineering Faculty of Mechanical and Industrial Eng. Jundi-shapur Uni. of Tech. Dezful Iran



Facility layout is a long-term decision and has a great impact on the system performance. When arranging a set of departments with unequal areas within a facility, the objective is to minimize material flow costs. In this paper, we present a new mathematical model for effectively finding global exact optimal solutions for the facility layout problem with fixed areas and variable aspect ratios. In contrast with some recent research in which considering a variable aspect ratio results in a nonlinear model, we formulate the variable aspect ratio of departments as decision variables into a linear model. Improving the effectiveness of mathematical models without introducing any extra integer variables causes the computational results to outperform present models in the literature. Also, we observed that, modeling the aspect ratio of departments as a decision variable improves the efficiency of the solution both in time and cost. In other words, if the aspect ratio of departments is modeled with more intermediate values, the CPU time and optimum value for the objective function are decreased in almost all cases.