A method for the identification of critical spare part target availability for a multi-echelon, multi-indenture system

Availability indicates the degree of equipment or weapons systems to work properly when they are needed, spare parts are important factors that can influence operational readiness and mission sustainability of equipment, and its shortage has an indirect impact on the system availability. By supportability simulation analysis, many supportability parameters of system can be obtained; however, the complicated hierarchy structure of supportability objects and the diverse relationship between spares supply make it difficult to acquire the critical spare part in LRUs and SRUs which has the greatest impact on system availability. When optimizing spare inventory, how to find out the critical spare part becomes the first problem to be solved. To solve this problem, firstly, the supply relationship between various types of spare parts in multi-echelon, multi-indenture is described, and a hierarchical structure model of system-LRU, LRU-SRU is established. Next, because the shortage of LRU may directly lead to the system failure, the impact of LRU backorder on the system availability can be quantitatively obtained, and because the shortage of SRU may indirectly lead to the system failure, a mathematical model is established to calculate the impact of SRU backorder on the system availability, by sorting in order of impacts on system can we identify the most important spare part which will increase/decrease the system availability most significantly. Finally, we use an case to verify the feasibility and effectiveness of this method.