Reliability Allocation Procedures in Complex Redundant Systems

In the last two decades, the reliability assessment acquired a fundamental role in many advanced technology applications where environment, personnel, and system safety are mandatory features. This study deals with reliability allocation (RA) procedures that are top-down techniques that allow apportioning of the system reliability goal between its components. This apportionment of reliability values among the various items making up the whole system is based on estimated achievable reliability, criticality, complexity, or any other relevant factors in the allocation process. In the first part, this paper analyzed the main allocation methods shown in the literature in order to enlarge the range of applicability of these allocation techniques, from series architectures to redundant architectures. In the second section, the RA methods were tested on two case studies in order to extend their applicability in the presence of very complex redundant architectures.