Economic optimization of the number of spare elements of technical systems regarding the reliability factor

Introduction. The article deals with optimization of the number of spare parts of technical systems. This is one of the tasks of the inventory management theory. Materials and Methods. The article reveals the peculiarities of optimization problems of spare parts kit (SPK) for scheduled and emergency repairs of the restored equipment and appropriate solution methods for them. The economic methods allow patterning the change of volume and structure of SPK with sufficient enough fine precision. As opti-mality criterion serves the minimum of total expenditures, ordering and cost of storage of SPK. The methods of calculation of separate components of the optimality criterion are presented. Results. The mentioned method determining the economically optimal number of spare elements is based on presented functional dependencies and an obvious but often ignored fact that the motion towards the optimum in this case should be considered as a two-step task that search the optimal number of SPK for elimination of emergency (sudden) failures of technical systems and optimal amount for their planned preventive repairs and inspections. Discussion and Conclusions. Solving the problem of definition of optimum quantity of SPK on each group of elements of equipment the presented method allows optimizing the structure of their stock.