Effectiveness and Predictability of Particle Damping

Abstract

In this paper, recent results of ongoing studies into the effectiveness and predictability of particle damping are discussed. Efforts have concentrated on characterizing and predicting the behavior of a wide range of potential particle materials, shapes, and sizes in the laboratory environment, as well as at elevated temperature. Methodologies used to generate data and extract the characteristics of the nonlinear damping phenomena are illustrated with interesting test results. Experimental results are compared to predictions from analytical simulations performed with an explicit code, based on the particle dynamics method, that has been developed in support of this work.

<title>Vibration damping in cylindrical shells filled with low-density low-wave-speed media</title>

“…In these studies involving relatively large, high-density particles, the damping mechanism is strongly nonlinear because it is the result of impacts and sliding among the particles. As reported by Fowler et al, 4 little damping is obtained at very low amplitudes of vibration.…”

“…Many researchers have studied the use of granular materials for vibration damping (e.g., 1 ). Papalou and Masri 2, 3 and Fowler et al 4 show that a container filled with granular material and coupled to a structure can be designed to achieve relatively high damping for a given added mass. Based on extensive experimental results, Papalou and Masri 2, 3 have developed an approximate method to predict the damping attained by dampers filled with steel balls of various sizes.…”

Movers and shakers: Granular damping in microgravity

“…This has been demonstrated in a number of experiments and Molecular Dynamics (MD) simulations, including investigations on the attenuation of a free spring or cantilever with an attached granular damper [5,7,[22][23][24]. The response of an oscillating cantilever with respect to periodic forcing has also been studied [25][26][27][28][29][30]. Even more complex systems have been investigated, such as the oscillation modes of a plate with an abundance of granulate filled cavities [31][32][33][34] with the aim of noise reduction [19].…”

<title>Damping of flexural vibration by coupling to low-density granular materials</title>

“…However, these high-density fills add a great deal of mass to a structure and hence are rarely used where weight is a concern. A container filled with granular material and coupled to a structure can be designed to achieve relatively high damping for a given added mass (Papalou and Masri 1, 2 and Fowler et al 3 ).…”

“…1, 2 Fowler et al employed a particledynamics simulation to model the behavior of a particle damper. 3 In these studies involving relatively large, high-density particles, the damping mechanism is strongly nonlinear because it is the result of impacts and sliding among the particles. As reported by Fowler et al, 3 little damping is obtained at very low amplitudes of vibration.…”