A Reliability Allocation Method Considering Failure Dependence

Traditional reliability allocation methods are based on the assumption that the subsystems of a system are independence in order to simplify the problem. However, this assumption could deviate from the engineering practice. To achieve the reliability requirement of the system, the subsystems must be allocated high reliability based on traditional reliability allocation approaches which neglect the dependence between subsystems. To solve this problem, an improved reliability allocation method is developed in this paper. Firstly, the failure dependence between subsystems of mechanical systems is characterized using Copula functions. Secondly, a reliability prediction model considering failure dependence is formulated based on Copula function, Furthermore, the improved reliability allocation method according to relative failure rate is proposed. Finally a numerical case is presented to illustrate the proposed approach. The optimal allocation result shows that the system can achieve reliability requirement without high reliability demand to some subsystems, which could reduce the unnecessary cost.Copyright © 2013 by ASME