Reliability analysis of a two-unit cold standby redundant system subject to a priority rule

The paper studies a two-unit cold standby redundant system subject to a priority rule and a preventive maintenance policy. All p.d.f’s involved are general. An important realistic behaviour of this model is characterized by the assumption that the non-priority unit has a memory i.e., it remembers the total elapsed operative time upon switch from standby to the operative state and conversely. The latter characteristic does not seem to be invoked in previous reliability models. A numerical example, with a computer-plotted graph for the mean life time of the system as a function of the replacement time, shows the optimal scheduled age replacement.