Simultaneous Vibration Control in Two Directions Using an Impact Damper System

摘要

A vibration model for a beam having impact damper on one end was created and damping characteristics when vibrating that model in two directions simultaneously was examined. An impact damper, which consists of walls and an impactor installed in a vibration system, is a type of damping device that makes use of collision phenomena. In the experimental equipment, a plate was attached to one end of a cantilever beam and a container was placed at each end of that plate. Each side of the container was equipped with a wall so that the impactor would collide with the walls and base surface when the container vibrated in the horizontal direction and vertical direction. Such a collision results in an exchange of energy reducing the vibrational energy of the device (container). The first mode of vibration (about 2 Hz) of the equipment corresponds to vibration in the horizontal direction and its second mode of vibration (about 20 Hz) corresponds to vibration in the vertical direction. These two vibration modes were excited simultaneously so that the container vibrated in two directions simultaneously. It was found that vibration in the vertical direction reduced the damping effect in the horizontal direction. The mechanical energy of the vibration system was calculated by numerical simulation and the mechanism behind this reduced damping effect in the horizontal direction due to vertical vibration was examined.