Reliability, Safety and Time-Domain Sensitivity Analysis of Double 2-out-of-2 Redundancy System Based on Markov Process and Multiple Beta Factor Model

The Markov process and multiple beta factor (MBF) model are combined for creating the reliability and safety models of double 2-out-2-of-2 redundancy system with regard of the effects of multiple factors, including failure detection rate, common-cause failure and failure rate of each module, for evaluating the system reliability and safety. Based on the Morris screening method, a time-domain sensitivity analysis method that is based on a large amount of random data with equal probability is proposed to study the effect of each factor on the system reliability and safety. Finally, the system model is simulated in MATLAB. The simulation demonstrates that system reliability and safety gradually decrease and the effect of each factor on them increases over time; the reliability is most sensitive to the failure rate of the CPU module; the safety is most sensitive to the failure detection rate; the comparator and switch modules have important effects on the reliability and safety; the common cause failure has small effect on the reliability and safety.