The Damping of Vibration With a Particle Impact Damper

The particle impact damper is a simple effective vibration absorber which consists of a solid particle constrained to move in a container attached to the primary vibrating body. In this paper two problems were studied theoretically. The first problem is to determine the damping characteristics of free oscillation from an initial displacement for a vertical system. The second one was the application of a particle impact damper under the forced vibrating condition. This damper should reduce the vibration amplitude for the vertical single degree freedom system when the driving force is harmonic. A major numerical analysis for free vibration systems with a particle damper was made with the assumption that the particle bed is a single particle impacting plastically with the vibrating body. To assess the damping characteristics in the free oscillating system, the equivalent damping ratio was determined using exponential curves fitting the response waveforms. It was found that damping effect increases with the mass ratio (m/M). Optimum clearances were obtained as about 1.2 to 1.5, and the reference data for the design of mass ratio and clearance were calculated to evaluate the damping performance of the particle impact damper. In the forced vibrating system, the theoretical solution for three possible types of the steady state impact motions, and the frequency response curves were obtained. It is shown that the periodic impact motions can be captured over a wide frequency range. In addition, a method for solving a forced vibration systems is also described