THE DISSIPATIVE CHARACTERISTICS OF OBLATE PARTICLES IN GRANULAR DAMPERS

In numerical models for granular dampers, particles are generally considered to be perfect spheres. However, in practical engineering applications these particles can slightly deviate from being true spheres. It has been observed experimentally that sphericity, which defines the proximity degree of a shape to a sphere, plays an important role in the amplitude dependent behaviour of granular dampers. This paper mainly examines the significance of the sphericity level for slightly oblate particles in a granular damper that are subjected to sinusoidal vibrations in the same direction as standard gravity. This investigation is carried out by evaluating the dissipated power from the granular medium by utilizing three-dimensional discrete element method simulations. Apart from the effect of amplitude of vibrations in the dissipated power, the relative contributions of frictional and inelastic collisional damping mechanisms in the overall power dissipation, are also investigated for varying sphericity levels of the oblate particles.