磁気ばねと磁気ダンパで構成された動吸振器による低固有振動数を持つ構造物の制振

抄録

The present work proposed the dynamic absorber for very low frequency structures using magnetic springs and magnetic dampers. The application of the magnetic springs and magnetic dampers allow the absorber to eliminate the influence of friction and to easily change the natural frequency and the damping ratio of the absorber. In the present work, the very low frequency structures composed of a pendulum and the absorber with two magnetic springs and two magnetic dampers have been constructed. Two optimum parameters of the absorber for the steady state vibration response and the transient vibration reduction of the very low frequency structures were derived analytically. The time response analysis using the numerical integration compared the effect of the two optimum parameters on the transient vibration. Furthermore, it was revealed that the vibration reduction effect by the absorber increased further by selecting the initial conditions of the main structure and the absorber properly. Next, the free vibration tests with the experimental apparatus were carried out, and it was confirmed that the experimental results agreed qualitatively with the numerical analysis results. In addition, it was confirmed that the application of the absorber properly tuned to the natural frequency and the damping ratio according to the initial conditions provided excellent vibration reduction effect.