Modeling and analysis of complex production systems with split, merge and re-entrant operations

Many complex production systems have split and merge operations to increase production capacity and variety, improve product quality, and implement product, control and scheduling policies. This dissertation presents analytical methods to model and analyze split and merge production systems with Bernoulli and exponential reliability machines and finite buffers under circulate, strictly circulate, priority and percentage policies. The recursive procedures for performance analysis are derived, and the convergence of the procedures and uniqueness of the solutions, along with the structural properties, are proved analytically. The accuracy of the estimation is justified numerically with high precision. In addition, comparisons among the effects of different policies in system performance are carried out.;Re-entrant lines are widely encountered in semiconductor and electronic manufacturing. In this dissertation, an approximation method to estimate the throughput of the re-entrant lines with exponential reliability machines, finite buffers under last buffer first serve (LBFS) scheduling policy is presented. Recursive procedures are developed to estimate system performance and structural properties are investigated. The results show that the proposed method provides an acceptable accuracy in performance evaluation for re-entrant lines. In addition, the results of c-Bottleneck (c-BN) identification based on the starvation and blockage of each machine in the re-entrant line are presented. It's shown that this is an effective method to identify c-BN in the re-entrant line.;A case study at an automotive powertrain assembly line with merge operations is introduced to illustrate the applicability of the method.;KEYWORDS: Throughput, Split. Merge, Re-entrant Line, Bottleneck...