Operational availability calculation methods of various series systems under the constraint of spare parts

Operational availability is one of the important indicators to measure support effectiveness of system, and spare parts supply is the key of support activities, so it is necessary to consider the spare parts when calculating operational availability. In the existing operational availability calculation methods, Markov renewal theory is rarely used for analyzing systems with spare parts; in the meantime, the availability calculation model based on inventory theory ignores that the replace and repair activity will be affected by delay in the supply of spare parts. To solve the above problem, firstly, the whole process is divided into two sub-processes, i.e., the replace and repair process of fault system and the maintenance and turnover process of failure parts, then the influence between the two sub-processes is analyzed. Secondly, a model that can compute the operational availability of multi-part series system with spare parts is given. Finally, numerical example shows that the operational availability of multi-part series system can be easily calculated by this model, compared with the calculating results of the model based on inventory theory, the results of this method are closer to the simulation results.