New allocation methods for repairable systems

Allocations are used to translate the reliability and availability goals of a system into reliability and availability goals for the subsystems. There are very few allocation methods available for repairable systems, even though most systems are repairable. The most popular allocation method for repairable systems assigns equal availabilities to subsystems to meet the desired system level availability. This method assumes that the non-failed components are continuously operating, even when the system is failed. This is not a valid assumption for most cases, and it is not compatible with recent changes made to the availability calculations in several prediction standards. In this paper, we propose necessary modifications to existing methods used for non-repairable systems to make them applicable to repairable systems. In addition to this, we also propose a new allocation method that is suitable for repairable systems. All the allocation methods proposed in this paper offer reliability engineers practical procedures to achieve availability goals