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Information × Registration Number 0219U102421, 0119U103482 , R & D reports Title Surface fatigue crack effect on the characteristics of turbine machine blade forced vibrations popup.stage_title Head Onyshchenko Yevheniia O., Registration Date 28-12-2019 Organization G.S. Pisarenko Institute for Problems of Strength of the National Academy of Sciences of Ukraine popup.description2  The object of investigation is the compressor blade airfoil. The purpose of the work is to establish patterns of influence of the presence of fatigue crack on the characteristics of the forced vibrations of the turbine blade airfoil and to analyze them for further use in the development of methods of vibration diagnostics of the technical condition of such structural elements. Research methods are numerical. The numerical methodology for calculating the forced vibrations of the blade airfoil finite element model with a surface fatigue crack is presented. The eigenfrequencies and vibration shapes of the undamaged blade airfoil and with an open and breathing crack are determined. It is shown that the use of modal characteristics in the vibration diagnostics of fatigue damage is ineffective, since it does not allow to record the change in the specified parameters. The results of numerical studies of the forced oscillations of the blade airfoil with a breathing crack at the frequencies of the fundamental and nonlinear resonances are presented, namely, the obtained spectra of the oscillation amplitudes and the corresponding amplitude ratios of the dominant harmonics. Graphs of dependences of vibrodiagnostic indices of the presence of a crack at pre-resonance and at frequencies of the basic, super- and subharmonic resonances from the place of registration of movements along the length of the airfoil are made. It is established that with the help of these dependences it is possible to determine the location of a crack, which is characterized by a sharp change in the magnitude of the ratio of the amplitudes of the dominant harmonics of displacements in its vicinity. Product Description popup.authors Kruts Vаdym O. Savchenko Kyrylo V. popup.nrat_date 2020-04-02 Close