磁気ばねを用いた動吸振器による低振動数構造物の制振に関する研究

抄録

The present study investigates the vibration suppression for a structure with low natural frequency using a dynamic absorber which is connected to a main system with two magnetic springs. It is important for the assurance of safety and the improvement of reliability to suppress vibration of flexible structures such as skyscrapers and space structures whose natural frequencies are very low. Though some countermeasures against a low frequency vibration such as a pendulum dynamic absorber have been proposed, the passive control technique for a very low frequency vibration can stand further improvement. In the present experimental apparatus, the main system and the dynamic absorber are composed of two rigid body pendulums in order to have a very low natural frequency. Two magnetic springs connecting between the main system and the dynamic absorber are composed of three permanent magnets whose same magnetic poles are faced each other and can adjust the natural frequency of the dynamic absorber by changing the distance between the magnets. It was confirmed by conducting the time history response analysis by the direct numerical integration that it is effective for the transient response by tuning to the optimal parameters of the dynamic absorber derived according to the fixed point theory. Furthermore, free vibration test results using the experimental apparatus revealed the effect of the dynamic absorber with magnetic spring on a very low frequency vibration and the experimental results agreed qualitatively with the numerical analysis results.