The multi-period plant layout problem considering stochastic workflow between facilities

Previous studies in layout optimization failed to consider the stochastic nature of workflow between facilities in multi-period planning horizon. Furthermore, previous layout models used materials handling cost as the sole criterion in the objective function and no constraints were imposed in the layouting problem. This study considered all these factors in the Quadratic Assignment model developed. The model considered transfer cost, set-up cost, and downtime cost in choosing the best layout for different periods. It was found that a relayout may be desired if the cost of relayouting is less than the total material handling cost expected to be incurred for succeeding periods if the layout had not been changed.