The probabilistic modeling of external common cause failure shocks in redundant systems

The effects of external common cause events on the reliability, availability and failure intenstity of operating m-out-of-n:G systems are modeled analytically in terms of general multiple failure rates (GMFR). The steady-state availability and the failure intensity are obtained for two repair strategies with arbitrary repair time distributions. The capacity factor, the mean idle time and the mean operating time between system failures are also obtained. Explicit results are presented for operating and standby systems with 1 ≤ m ≤ n ≤ 4. A numerical example illustrates the effects of different repair strategies.