A hybrid Markov system dynamics approach for availability analysis of degraded systems

Time dependent availability is an important index used for evaluation of operational performance of repairable industrial systems. Traditionally, Markov analysis procedures are carried out for such studies. This becomes mathematically intensive when applied for larger systems. Moreover, this method does not indicate at what time a system reaches its steady state. However, in practice it is important to know at what time the steady state actually begins. This paper proposes a hybrid approach called as Markov System Dynamics (MSD) approach which combines the Markov model with system dynamics simulation for the time dependent availability analysis. The proposed method is also capable to compute the repairable system steady state time. The new approach is illustrated for a three state degraded system with repair. The results are compared with that obtained by traditional Markov analysis to validate the Markov System Dynamics (MSD) approach as an alternative for the time dependent availability analysis.