Availability analysis of repairable redundant system with three types of failures subject to common cause failure

This paper deals with the availability analysis of a redundant system consisting of N-non-identical components and S warm standby components under the care of single repair facility. The system may fail due to three reasons: 1) human error such as wrong adjustments in the design or development phase of the system or system may undergo damage during maintenance; 2) hardware failure; and 3) software failure. The incorporation of common cause failure gives the major impact on the system performance since it may cause dependant failures of some or all components of the system. An irreducible Markov process is used to construct the system of governing differential equations associated with three types of failure subject to common cause failure. The system availability for different configurations under transient condition is examined by using a numerical approach based on Runge-Kutta method of fourth order. Further, the sensitivity analysis is facilitated to demonstrate the validity of analytical results by taking a numerical illustration. The effect of different parameters on system performance indices are demonstrated graphically.