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Application opportunity of IT's contactless vibrodiagnostic system for measurement of dynamic behaviour of rotor bladed wheels.
Vaněk, František ; Pešek, Luděk ; Procházka, Pavel ; Cibulka, Jan ; Turinský, M. ; Laštovka, B.
Variable excitation forces evoke a rotor blade vibration at jet engines. For description of the blade vibrations, parameters such as modes, frequencies and amplitudes, are evaluated in different operational regimes of engines. Since the operational forces are not fully known and mechanical parameters of the blades changes during sirvece the vibrodiagnostic measuring system VDS.IT was developed in IT AS CR. This system can be used for long-term measurement of vibration of all free-ended blades of rotors. Since the latest development of shrouded blades this system has been modified and fully tested in the Experimental laboratory of Škoda Power, Plzeň. The changes and results are discussed in this contribution.
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Measurement and analysis of tram wheel vibration at riding on track
Pešek, Luděk ; Vaněk, František ; Cibulka, Jan ; Vaněk, P. ; Boháč, T.
In the contribution the design, realization and results of vibro-acoustic measurements on the riding tram wheel is presented. The operational tests were performed on the tram KT8D5 of DPMB Brno. The tram wheel with a special rubber padding design was equiped with add-on vibro-acoustic dampers. Efficiency of the add-on dampers was evaluated from comparison tests on the tram wheel with and without these dampers. Third octave and time-frequency analysis of the measured vibro signals is herein presented for a bow track passage. For analysis of operational vibration modes the FE model of the wheel with add-on dampers was developed and applied.
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Identification and reconstruction of non-conservative system
Kozánek, Jan ; Mazúch, T.
Identification and reconstruction of non-conservative system. The identification (via least squares smoothing method of the transfer function) and the reconstuction of laboratory dynamic systems with the accent to the so-called condensability condition are considered. It enables one to reconstuct spectrally and modally faithful coefficient matrices of vibrating systems. Various reconstruction approaches are compared each to other.
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To some dynamic properties of parametric - heteronomous systems with internal kinematic couplings and split power flow
Hortel, Milan ; Škuderová, Alena
The contribution deals partly with the problems of influence of material damping of gearing by normal and inverse mesh and the effect of viscous damping of lubricant surrounding, i.e. the influence of oil during cog contact bounce in the gap - technological backlash and partly with the analysis of issue causation of sharp discontinuity locality in the resonance characteristics, which is associated with the cog contact bounce with the impact effects in dependence with given resonance tuning, the gear mesh duration term on stiffness level of the parametric stiffness function or the modify stiffness function, inclusive the time phase shifts of relative motion towards these stiffness function.
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