An integrated method for incorporating common cause failures in system analysis

Abstract

This paper proposes an integrated method for incorporating common cause failures (CCF) in system analysis. CCF are simultaneous failures of multiple components due to a common cause (CC). CCF tend to increase the joint-failure probabilities and can have dominant contribution to the system unreliability. Basically there are two methods for CCF analysis, the explicit method and the implicit method. Both methods have their own shortcomings, especially when they are applied to large-scale fault trees. Our method provides accurate and efficient CCF analysis by incorporating implicit method into binary decision diagram (BDD) and applying Markov model in dynamic fault tree (DFT) analysis. It avoids the disadvantages in the explicit method or the implicit method and is customized for currently widely-used DFT model.