Vibration quenching device using Hula-Hoop and displacement magnification mechanism

Abstract

This paper deals with the vibration quenching problem of the single-degree-of-freedom system with a limited power supply using a Hula-Hoop and displacement magnification mechanism. This system is forced by the centrifugal force of rotating unbalance. If the unbalance is small, the amplitude of vibration of the main system becomes small and Hula-Hoop does not rotate. Therefore, the vibration of main system is not quenched. To solve this problem, the two types of displacement magnification mechanisms are adopted, namely, the one is the mechanism using beams with fixed ends that move and the other is that using cantilever. The quenching effects and the quenching frequency regions are studied. Following was made clear by the numerical integration of the equation of motion and the experiment: (1) The main system is quenched well by enlarging the displacement at the rotational center of Hula-Hoop using each type of displacement magnification mechanism. (2) The optimal vibration quenching condition of the Hula-Hoop and the displacement magnification mechanism for the first mode is obtained. (3) The frequency regions suitable for vibration quenching are the regions those are higher than the natural frequencies. (4) The vibration mode and the phase relation between unbalance and Hula-Hoop are made clear in each vibration mode. (5) The characteristics of the solutions obtained by the numerical integration method coincide qualitatively with those of the results obtained by the experiment.

Keywords

• nonlinear vibration
• vibration control device
• forced vibration
• hula-hoop
• displacement magnification