DEVELOPMENT OF A QUEUEING MODEL FOR EFFECTIVE CREW SIZE IN MAINTENANCE OPERATIONS

Abstract

This thesis describes the use of heuristics and cost models based on the queueing theory to determine effective crew size for maintenance operations. The model was applied to mechanical maintenance workshop, Federal University of Technology, Akure, due to the fact that it has characteristics of external maintenance system. A computer software in "QBASIC" was developed to solve the model. The results obtained from this approach showed that, the use of heuristics generated effective crew size of one (a seven-man crew), while that of maintenance cost model was two, given a difference of 50%. Also, by using deterministic cost model 1.5 secs. was used to process the results, while the time used to process the results in stochastic cost model depends on maximum simulation time MCT, but for heuristic it was just 0.5 second. The results revealed the advantage of using heuristic over complex equations of maintenance cost models. Therefore, to achieve higher response rate, the jobshop should operate on two crews. Although, management can decide to operate on one crew (as prescribed by heuristic) if other maintenance strategic decisions are in her favour than any other jobshops in the environment. Finally, the results generated by both deterministic and stochastic cost models showed that both are equally likely to describe the maintenance jobshop under study