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Effect of particle damper under torsional vibration

Continually using the machine with the vibration may lead to a blood circulation failure to a hand. Vertical vibration and the torsional vibration are generated on the handle part of those machines. If the particle damper is attached on such a machine, an impact to act on a hand may be reduced. The particle damper is a device decreasing vibration by many particles which are filled into the container of the collision damper. It is difficult to experimentally observe the complex behavior of particles in the container since compressive forces, frictional forces, and impacts are generated between particles and the wall. Therefore, calculation of particle behavior by modeling a discrete body that contains the particles and the container is necessary. Discrete element method (DEM) might be one of the effective methods for its simulation. In this study, the torsional vibration is focused on and the characteristic of the damper examined through experiments and DEM simulation. In the experiment and simulation, many spherical particles as impactors were filled into a container. The container was given periodically a twist motion. The calculation results were compared with the experimental results by means of provided resonance curve. As a result, it turned out that the torsional vibration decreases when the selected particles which have a suitable particle diameter and a filling ratio were filled into the container.