Bounded-set approach to the evaluation of the reliability of fault-tolerant systems. Part 2: Unpowered spares, nonconstant failure rate, nonaggregatable systems

In the companion paper, we developed a bounded-set approach to enable the modelling of closed Markov systems with powered spares. In the paper, we will further develop the approach to enable the modelling of closed Markov systems with unpowered spares, closed non-Markov systems; i.e. systems with modules which have arbitrary failure time distributions. We also apply the approach to model a system whose components cannot be readily aggregated into a number of independent subsystems. An efficient algorithm for computer implementation of the bounded-set approach is also given. In the first case, it is also possible to model these systems using the more established Markov state transition approach. A comparison of the two results is therefore given.