Objectives  The previous researches into the reliability analysis on common cause failure mostly assume that the common cause failure event will necessarily cause the relevant unit to fail. This assumption is accurate for electronic components, but it can lead to state loss problems for mechanical equipment with high reliability and complex structure. Therefore, a multi-state reliability calculation method that considers the Probabilistic Common Cause Failure(PCCF) is proposed through theoretical derivation.

  Methods  The common causes include fatal common cause and non-fatal common cause, and the effect of each common cause is applied to each unit, and the Universal Generating Function(UGF) model of each unit using explicit method is established. The existing method and the method of this paper are compared in terms of the calculation results of unit independent failure, fatal PCCF, and non-fatal PCCF.

  Results  The results verify the validity of the hypothesis of probabilistic common cause failure and the validity of the proposed reliability calculation method.

  Conclusions  Compared with the traditional common cause failure analysis method, if the analysis method of probabilistic common cause failure is used, the reliability calculation result is more accurate, which can solve the problem of unit and system state loss.