Abstract
This paper deals with the vibration quenching of mechanical structures using a Hula-Hoop. Quenching of vertical vibration of the one-degree-of-freedom system forced by centrifugal force is compared with that of horizontal one. Following was made clear from the numerical analysis: (1) The device using Hula-Hoop is very effective for not only horizontal vibration quenching but also vertical one in the region exceeding the resonant frequency. (2) On the vibration quenching problem in the vertical vibration, if there is the parametric excitation relation between the Hula-Hoop and the main system, the Hula-Hoop moves as pendulum in the region near resonance frequency and quenching the main system is possible. However, if the mass of Hula-Hoop is light, the quenching by autoparametric excitation is not enough. (3) The smaller the damping of the hula-hoop is, the more the vibration of main system is quenched. (4) In the vibration quenching problem using Hula-Hoop, the larger the mass of the Hula-Hoop is, or the longer the length between rotational center and gravity center of the Hula-Hoop is, the more effective the Hula-Hoop is. (5) It is suggested that the system with essentially large unbalance may be quenched in large frequency region using autoparametric excitation and rotation of Hula-Hoop.
