Vibration Damping Characteristic of Structures Packed with Balls and Liquid

(Observation of Ball Behavior and Analysis of Drag)

Abstract

The damping characteristics of a square pipe packed with steel balls and silicon oil can be improved by a combination of large balls and high viscosity oil and a combination of small balls and low viscosity oil. However, the reason for those has not been made clear yet. In this paper, the ball behaviors in impulsive excitation experiments are observed using a high speed camera, and the drag acting on a ball in silicon oil in a square pipe is numerically analyzed under the condition of the first vibration mode of the pipe when the square pipe vibrated are analyzed by ANSYS CFX software. It is shown that the ball behaviors are different from one combination of ball size and oil viscosity to another and that a high damping capacity is obtained when the contact between the balls and the square pipe frequently takes place.