Composite performance-dependability analysis of cellular manufacturing systems

This paper deals with the transient analysis of manufacturing systems in the presence of failures and repairs. The exact model is decomposed into 1) a structure state process, modeling the failure and repair events which occur at a slower time scale, and 2) a performance model, modeling the part processing and material movement events occurring at a faster time scale. The solutions of these two models are combined to yield the mean and standard deviation of cumulative production over an interval. Such studies, called combined performance-dependability studies, are important in the manufacturing context. We define combined performance and dependability (performability) measures in the manufacturing context, and provide a mathematical formulation. Detailed performability studies are carried out for cellular manufacturing systems, in particular for a flexible manufacturing cell and a two-cell manufacturing system featuring blocking and prioritized, centralized repair. We also present several numerical examples.