An Analysis of the Inventory/Repair Decision in a Multi-Echelon Environment.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
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The initial phase of the dissertation involved developing a dynamic simulation model to analyze the performance of the multi-echelon system under varying system design and logistic system conditions. The simulation model was validated using operating data from an Air Force tactical operating system in its first 45 months of operation. The model predicted cumulative operating hours and maintenance hours to within four percent of the observed values. The validated model was used to identify key system design and logistic system factors. A series of single factor experiments were conducted to examine the effects of each of sixteen variables on seven key performance measures. A full factorial experimental design was then used to examine the main and interaction effects among the seven most significant variables. The results indicated that increases in mean time between failure, inventory levels and percent of local repair consistently had a favorable impact on the multi-echelon system resulting in shorter queue times, lower average downtime and more systems available for operation. Given an acquisition objective of minimizing the average downtime per failure, the research showed the level of repair had a more favorable on performance than increasing reliability or investing in more inventory.
- Fluid Mechanics