Particle Impact Damper Research Articles

Performance of a New Fine Particle Impact Damper

The energy dissipation mechanisms of conventional impact damper (CID) are mainly momentum exchange and friction. During the impact process, a lot of vibration energy cannot be exhausted but reverberated among the vibration partners. Besides, the CID may produce the additional vibration to the system or even amplify the response in the low‐frequency vibration. To overcome these shortcomings, this paper proposes a new fine particle impact damper (FPID) which for the first time introduces the fine particle plastic deformation as an irreversible energy sink. Then, the experiments of the cantilevered beam with the CID and that with the FPID are, respectively, carried out to investigate the behavior of FPID. The experimental results indicate that the FPID has a better performance in vibration damping than in the CID and the FPID works well in control of the vibration with frequency lower than 50 Hz, which is absent to the non‐obstructive particle damper. Thus, the FPID has a bright and significant application future because most of the mechanical vibration falls in the range of low freqency.

Development of a design curve for Particle Impact Dampers

Particle impact dampers (PIDs) are enclosures partially filled with particles of various sizes and materials. When attached to a vibrating structure, they add damping by dissipating energy through inelastic particle-enclosure collisions as well as through momentum transfer. The development of a design curve that can be used to predict the damping characteristics of particle impact dampers is presented here. A power measurement technique enabled time-efficient measurement of the damping properties of the PID. This technique enjoys several advantages over traditional loss-factor measurements, including the flexibility to analyze the behavior of the PID at any frequency or amplitude of the excitation, and the ability to estimate the damping contribution for any structure operating within the bounds of the design curve. Using the power measurement technique, a large number of experiments were conducted to determine the effects of vibration amplitude, excitation frequency, gap size, nominal particle diameter, and particle mass on the dissipated power and effective mass of the PID. The power data were then systematically collapsed into a pair of two-dimensional master design curves with non-dimensional quantities for the axes. The quantities are comprised of combinations of design parameters. For specific applications, a damping efficiency of the PID may be predicted from the design curves. A physical interpretation of the design curves is given. The performance of a PID on a structure verified the predictive capabilities.

The damping performance of a single particle impact damper

This paper presents results from computer simulations used to investigate the damping performance of a single particle vertical impact damper over a wide range of excitation frequencies and amplitudes, particle-to-structure mass ratios, lid clearance ratios, structural damping ratios, and coefficients of restitution. Measurements of the damping performance, particle flight times, and structure contact times are presented. Performance at both the structure's undamped natural frequency and off-resonant conditions are studied in depth. Maximum damping at a fixed oscillation frequency occurs at an optimal lid height that increases with increasing mass ratio, increasing structural damping ratio, but decreases with coefficient of restitution. The corresponding maximum degree of damping increases with increasing mass ratio and coefficient of restitution, but decreases with increasing structural damping ratio. Field plots of the damping ratio are also presented as functions of oscillation amplitude and frequency to demonstrate the damper performance over a range of design parameters and operating conditions.

Particle impact damping: effect of mass ratio, material, and shape

Particle impact damping (PID) is measured for a cantilevered beam with a particle-filled enclosure attached to its free end. PID due to different particle materials is measured: lead spheres, steel spheres, glass spheres, tungsten carbide pellets, lead dust, steel dust, and sand.

Damping Effect of Particle Impact Dampers Using a Cylindrical Container.

This paper presents the results of an experimental and analytical study of the performance of particle impact dampers using a cylindrical container. This damping is a form of impact damping in which particles collides with the cylindrical surface of the container. The dynamics of the damper is solved by Discrete Element Method (DEM). The validity of the numerical method is examined by comparison with experimental results. The effect of some of the major system parameters such as the mass ratio, container dimensions and particle radius on the structural damping is studied.

PARTICLE IMPACT DAMPING

Particle impact damping (PID) is a means for achieving high structural damping by the use of a particle-filled enclosure attached to the structure in a region of high displacements. The particles absorb kinetic energy of the structure and convert it into heat through inelastic collisions between the particles and the enclosure, and amongst the particles. In this work, PID is measured for a cantilevered aluminium beam with the damping enclosure attached to its free end; lead particles are used in this study. The effect of acceleration amplitude and clearance inside the enclosure on PID is studied. PID is found to be highly non-linear. Perhaps the most useful observation is that for a very small weight penalty (about 6%), the maximum specific damping capacity (SDC) is about 50%, which is more than one order of magnitude higher than the intrinsic material damping of a majority of structural metals (O(1%)). Driven by the experimental observations, an elementary analytical model of PID is constructed. A satisfactory comparison between the theory and the experiment is observed. An encouraging result is that in spite of its simplicity, the model captures the essential physics of PID.