Spare parts provisioning for multiple -out-of-:G systems

This article considers a repair shop that fixes failed components from different k-out-of-n:G systems. It is assumed that each system consists of the same type of component; to increase availability, a certain number of critical components are stocked as spare parts. A shared inventory that serves all systems and/or reserved inventories for each system are allowed; this is called a hybrid model. Additionally, two alternative dispatching rules for the repaired component are considered. The destination for a repaired component can be chosen either on a first-come first-served basis or by following a static priority rule. The analysis gives the steady-state system size distribution of the two alternative models at the repair shop. Numerical examples are performed that minimize the spare parts held while subjecting the availability of each system to exceed a targeted value. It is shown that a hybrid priority policy is better than a hybrid first-come first-served policy, unless the availabilities of systems are close.