Experimental and Numerical Studies on the Efficiency of Damping upon Horizontal Stirring of Granular Materials

  • Ishizeki, Kazuki (Graduate School Engineering and Science, Shib)
  • Saeki, Masato (Shibaura Institute of Technology)

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Particle damping devices are often used to attenuate the vibration occurring in mechanical units. Their damping performance can be produced by using suitable granular materials (sands and steel balls) in a wide temperature range. Particle dampers are typical of particle damping devices. Since particle dampers consist of granular materials in the cavity attached to the primary mass, they are simple structures. Collision and friction between the wall of the cavity and the particles result in a reduction of the vibration amplitude. However, granular materials remain locked together in the cavity when the vibration acceleration of the primary system is low. In the case of a low acceleration of the primary system, tuned mass dampers with granular materials can be effective. As the dampers consist of an auxiliary mass-spring system, frequent maintenance is required. Shimoji et al. investigated the efficiency of damping upon stirring granular materials. They showed that stirring granular materials can cause high energy dissipation at a low acceleration. However, the study has focused on the damping characteristics induced by vertical stirring. The objective of this study is to investigate the efficiency of damping induced by horizontal stirring granular materials. In the experimental approach, a cylindrical mixer with a flat blade was used. As the rotating axis of the blade was driven by a shaker through a ball screw mechanism, the blade rotated sinusoidally. The effects of packing ratio, particle diameter and particle material on the energy dissipation were examined experimentally. To capture the behaviour of the entire system in detail, the energy dissipation was calculated by EDEM software based on the discrete element method. Comparison between the experimental and numerical results showed that accurate estimates of the energy dissipation can be obtained.