Reliability analysis of systems which operate in duty cycles

The unreliability of a two component parallel system with Weibull component failure distributions is analyzed. The system operates in discrete duty cycles and is repaired only between duty cycles. A complex repair strategy embodying both scheduled maintenance and unscheduled, deferred maintenance is considered. System unreliability is computed by two methods. The first method is based on the renewal equation and provides a formula for asymptotic unreliability based on the first system failure sequence. In the second method the system is modeled as a discrete time Markov chain. Transitions between states are based on component failure behavior and repair policy. System unreliability is obtained as a function of duty cycle.