A comparison of availability centered inventory models using the TIGER simulation program

Developing and updating shipboard repair part allowances for the tremendous number of Navy shipboard equipments is a large scale, complex task. In order to avoid excessive downtime on these critical equipments, more sophisticated allowance computation techniques which account for system characteristics and availability requirements are needed. This study examines three availability centered inventory models used to determine repair part allowances. The models are the Availability Centered Inventory Model (ACIM), the Lagrangian Equipment Optimization (LEO) model, and the Spares Economically and Automatically Selected to Criteria Applied for Performance Effectiveness (SEASCAPE) model. Model effectiveness will be compared using a hypothetical ship steering system. After inventory levels are computed by each of the models through internal optimization techniques, operational availability (A sub o) is estimated by simulation of a ship's mission timeline using the Naval Sea Systems Command's TIGER program. The comparison is made by examining the availability of the hypothetical system using the TIGER model under the following conditions: fixed budget, variable budgets, and variable mean supply response times (MSRT)