The effect of particle surface roughness on granular energy dissipation performance

Granular materials can be effectively utilised to reduce structure-borne noise and structural vibrations. However, since granular damping shows non-linear characteristics and is affected by several different parameters such as particle shape, a granular damper should be designed considering the factors that may change granular energy dissipation behaviour. The particles used in a granular damper are generally assumed as having a certain geometric shape. However, particle surfaces can deviate from the pre-defined shape due to manufacturing limitations or wear during operation. This experimental study investigates the extent of particle surface distortion on the energy dissipation performance of a partially filled granular damper exposed to harmonic excitation parallel to the direction of gravity. The effect of the particle surface is evaluated over a range of amplitude and frequency conditions. Moulded and 3D printed spherical particles are used to indicate smooth and non-smooth particle shapes, respectively. In order to quantify the particle surface smoothness, a set of surface roughness measurements is carried out. A dissipated power measurement test rig is used to assess dissipative performances of smooth and non-smooth spherical particle types in a cylindrical granular damper enclosure.