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Numerical Simulation of a Two-Crack Rotor System Supported by Radial Active Magnetic Bearings
Ferfecki, Petr ; Ondrouch, Jan
In this work a computational simulation is utilized to investigate the steady-state response of a two-crack rotor system supported by radial active magnetic bearings on an excitation by centrifugal forces of discs unbalances. The static deflection of a shaft is considered larger than vibration amplitude of a shaft and therefore a so-called breathing behaviour of cracks is introduced. Parametric study has been carried out in order to investigate influence of different values of the angle between cracks on the steady-state response of a rotor system. The results presented in this work can therefore help with detection of cracks in the shaft.
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Dynamics of Machines 2008
Pešek, Luděk
Traditional national colloquium with international participation is an assembly of research works on mechanics of solids aimed at the dynamics of machines.
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The vibrodiagnostic system VDS-UT2 for the investigation of a tram wheel operational vibration and deformation
Pešek, Luděk ; Vaněk, František ; Balda, Miroslav ; Procházka, Pavel ; Vaněk, Petr ; Cibulka, Jan ; Bula, Vítězslav
The system consists of both measuring, acquisition and processing tools for monitoring of tram wheel and wheel set operational parameters,e.g.static and dynamic deformation, displacement, velocity, acceleration and temperature. The measuring on the rotating wheel is realized both by telemetric and by time difference system. Measured data can be remote observed via internet connection with the control PC. Tha acquisition system by Starmans s.r.o provides continuous analog and digital data collection. The control PC processes digital logical signals and evaluates time intervals representing circumferential turning angles between disk and rim. In the contribution the diagnostic system is described and the measured data with damage analysis are presented.
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Dynamické vlastnosti plynových ložisek
Kozánek, Jan ; Šimek, J. ; Steinbauer, P. ; Neusser, Z.
The test stand for identification of aerostatic bearing stiffness and damping coefficients was brought into operation and some additional modifications were made to ensure successful dynamical experiments. Dynamic model of the test stand, enabling determination of stiffness and damping coefficients from measured response to harmonic excitation, was devised and programmed. The stiffness and damping coefficients of test bearings were calculated for comparison of theoretical and experimental values. Results of dynamic coefficients calculation are presented together with results of initial identifications on test stand.
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Systém s rázy buzený zdrojem omezeného výkonu
Půst, Ladislav
Electromechanical system with one degree of freedom in mechanical oscillating part and other degrees in rotation a electrical subsystems is investigated by means of numerical solution of derived equations in dimensionless form. The most important nonlinearities are impacts of the main body on the stiff but deformable stop. Other nonlinear effects are introduced into system by the force transformation from unbalance exciter with limited power into the oscillating subsystem and also by nonlinear magnetic flux in the driving electromotor. Presented numerical simulation was focused on the study of the influence of exciting unbalance level on the time histories of caused oscillations and of phase trajectories. The various responses were shown and discussed in examples.
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