PERFORMANCE ANALYSIS OF ASSEMBLY DISASSEMBLY SYSTEMS WITH UNRELIABLE MACHINES AND RANDOM PROCESSING TIMES/

This paper presents an efficient method to evaluate performance of tre e-structured assembly/disassembly (AD) systems with finite buffer capa city. The times to failure, the times to repair, and the processing ti mes are assumed to be exponentially distributed. The method is based o n an extension of a decomposition method originally applied to perform ance evaluation of transfer lines. The method decomposes a K-machine t ree-structured AD system to a system of K - 1 two-machine lines and th en finds the processing rates, failure rates and repair rates of the d ecomposed system that make performance of the two systems close to eac h other. To determine those rates of the decomposed system, we derive 6(K - 1) equations based on interruption of flow, resumption of flow, and flow rate-idle time relations, and suggest two methods, which use the equations in different ways. Results from computational experiment s show that the suggested decomposition methods give good estimates in a short time.