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Impact damper with Hertz's dynamic contact
Půst, Ladislav
The paper contains results of analytical and numerical investigation of the oscillations of 2DOF system in which the amplitudes are limited by one- or two-sided stops. It is shown that the application of stops in absorber subsystem can get lower the amplitudes of basic external forced system approx to 50%. The efficiency of stops application on self-excited system is very low.
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Identification of tram wheel with vibro-dissipation layer
Pešek, Luděk ; Veselý, Jan ; Podruh, J.
The wheels as vibration transformation elements and noise emitters substantially contribute to the total noise level of riding vehicle. We aimed at investigation of dynamic behavior of railway tram wheel with a special construction. This wheel has a rim separated from disk by rubber cushioning. The selected dynamic parameters of the wheel are modal, frequency and damping characteristics. Proportional damping was implemented into rubber layer of FE wheel model as the first approximation of dissipation behavior.
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Model of vocal fold oscillation in viscous fluid flow
Horáček, Jaromír
A vibrating element on an elastic foundation in the wall of a channel conveying air approximates the vocal fold oscillations. The viscous incompressible 1-D fluid flow theory is used and a generally defined shape of the vocal fold is considered. The numerical solution yields the instability thresholds, which are close to the known physiological data for phonation thresholds. The viscosity is important for very small opening of the glottis where its effect on instability boundaries increases.
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