Sitnikov A. Forecasting operating changes in the technical state of electromagnetically driven valves at the stage of designing.

The dissertation is devoted to the development of scientific bases and practical recommendations on forecasting possible operating changes in the technical state of electromagnetic valves (EMV) with an electromagnetic drive over resource completion. A classification of small EMVs used in aircraft systems is presented. It was found out that particular features of operating loads and basic degradation processes which result in substantial changes in the technical state of EMVs and determine their resource possibilities. In an experimental way the character and intensity of changes of basic structural and functional parameters of valves of considered types have been determined from the number of working cycles. Developed theoretical bases of designing operating changes in the technical state of EMV with the use of probabilistic model of accumulation of damages in elements and units of EMV. Mathematical models have been developed and on their basis proper methods of forecasting change of structural and functional parameters of EMV with the use of least-squares method, method of extrapolation and method of the guided selection. The method of determination of the EMV resource is developed based on the analysis of elements of valve of casual damage processes taking into account the operating loads and description of durability of the elements material. It is discovered that the operation of EMV with the drive of Dual Pushing-Pulling type till failure due to fatigue destruction of the rod neck depends on specific kinetic energy of the drive mobile system motion. On the basis of experimental research the method of forecasting EMV failure-free performance signs has been developed making use of power criteria. The main results of research have been put into practical designing of EMV in the Kiev central design bureau of fittings.