Particle damping, an effective passive vibration control technology, is developing dramatically at the present stage, especially in the aerospace and machinery fields. The aim of this paper is to provide an overview of particle damping technology, beginning with its basic concept, developmental history, and research status all over the world. Furthermore, various interpretations of the underlying damping mechanism are introduced and discussed in detail. The theoretical analysis and numerical simulation, together with their pros and cons are systematically expounded, in which a discrete element method of simulating a multi-degree-of-freedom structure with a particle damper system is illustrated. Moreover, on the basis of previous studies, a simplified method to analyze the complicated nonlinear particle damping is proposed, in which all particles are modeled as a single mass, thereby simplifying its use by practicing engineers. In order to broaden the applicability of particle dampers, it is necessary to implement the coupled algorithm of finite element method and discrete element method. In addition, the characteristics of experimental studies on particle damping are also summarized. Finally, the application of particle damping technology in the aerospace field, machinery field, lifeline engineering, and civil engineering is reviewed at length. As a new trend in structural vibration control, the application of particle damping in civil engineering is just at the beginning. The advantages and potential applications are demonstrated, whereas the difficulties and deficiencies in the present studies are also discussed. The paper concludes by suggesting future developments involving semi-active approaches that can enhance the effectiveness of particle dampers when used in conjunction with structures subjected to nonstationary excitation, such as earthquakes and similar nonstationary random excitations.

Particle impact dampers: Past, present, and future

Particle dynamics simulations of a piston-based particle damper

Soft hollow particle damping identification in honeycomb structures

Partial filling of a honeycomb structure by granular materials for vibration and noise reduction

By means of particle-based numerical simulations using the discrete element method, we address the question of how the performance of granular dampers is affected by the shape of the granular particles. In consistence with previous experiments performed with nearly spherical particles we find that independently of the particles' shape, the granular system is characterized by a gas-like regime for small amplitudes of the container's oscillation and by a collect-and-collide regime for large amplitude forcing. Both regimes are separated by an optimal operation mode—the critical amplitude of the damping oscillation for which the energy dissipation is maximal—which is independent of the particle shape for given conditions of particle mass, material properties and number of particles. However, in the gas-like regime, we find that spherical particles lead to more efficient energy dissipation compared to complex shaped particles of the same mass. In this regime, a dependence on the damper's efficiency on the particle shape is found.

https://iopscience.iop.org/article/10.1088/1367-2630/18/7/073049/pdf

Granular dampers: does particle shape matter?

Particle damping is a generalization of impact damping technology (also known as acceleration dampers), but also provide additional damping mechanisms when compared with other kinetic energy based vibration dissipation devices. Due to their inherent design simplicity, in recent years there has been considerable interest in this technology. Most of the reported results have been obtained empirically, however, recently there has been some activity in the construction of analytical/numerical models to simulate the energy dissipating performance of particle dampers. The work described in this paper documents experimental work and representative test results of various particle dampers used to suppress excessive vibration of cantilever type space structural subsystems of various sizes subjected to transient and steady-state vibratory disturbances. It is experimentally demonstrates that the performance of these devices are highly amplitude dependant. It is also experimentally shown that there are three distinct damping performance regions for transient type excitations. In addition to partially filled cavity particle dampers, other particle dampers are also investigated such as particles-in-ball and preloaded particle dampers. In its simplest form, a particle damper consists of a cavity box of various shapes and sizes that are partially filled with particles. Particles can be metallic, ceramic, polymeric, composite or a mixture of various materials. The particle size may vary from application to application and may vary from a few micro-inches to a tenth of an inch or more. The shape of the particles may be near spherical, cylindrical or irregular in shape. The shape, size and material of the particles will influence flow characteristics of the particles in the cavity. Other particle damper configurations are also experimentally studies. In one configuration a polymeric ball is partially filled with particles. The ball is then placed in a cavity that is secured to a vibrating structure. The vibration sets the ball in motion in the cavity. Since the ball is only partially filled with particles, any rolling action of the ball will set the particles in motion against one another and maintain a new surface level, similar to a fluid leveling itself to maintain equilibrium due to gravity. The ball will eventually collide with cavity walls thus functioning as an impact damper with additional frictional losses due to particle friction and other losses due to elastic/plastic deformation of particles and the polymeric material of the ball. In another application, the particles are placed in a confined elastic cavity such as a metallic bellows or a rubber tube and sealed at the ends. The elastic walls of the rubber tube will induce compressive forces on the particles as more and more particles are stuffed into the tube. The amount of particles in the elastic cavity will determine the amount of preload on the particles. Any bending action of the particle filled elastic tube will be accompanied with relative rubbing motion among the particles, thus dissipating energy by dry friction.

Stepan S. Simonian

Papers

Particle Damping Applications