Operational availability modeling and simulation evaluation

In this paper, we first investigate the concept and measuring models of system operational availability, and their limitations. To overcome the limitations of the existing models, we present an instantaneous operational availability model and an average operational availability model, as well as a simulation-based method for evaluating those two models. The distinction between the two models is illustrated by simulation examples. The sensitivity analysis of impacting factors shows that the inherent reliability of a system is the key factor affecting the operational availability, thus improving system inherent reliability is the most effective way to improve the operational availability. The second most important factor is the number of initial spare parts. Analysis results also show that the operational availability has not increased significantly by increasing the number of maintenance personnel or cutting down the mean maintenance time.