Groundborne vibration attenuation by particulate dampers to reduce building vibration at sonic frequencies

Particulate medium can act as efficient damper for building vibrations. Mechanical properties of particulate material and their size distributions determine their vibration absorption characteristics. Unconsolidated particulate damper of uniform size is shown to have bandpass filter behavior for mechanical vibrations that are transmitted through them. The dampers absorption spectrum also shows bandgap structure where mechanical vibration in each frequency range is strongly absorbed. We use samples of uniform size spherical particulates that are subjected to mechanical vibrations in the audible frequency range to determine their absorption characteristics as a function of particle size, frequency, intensity, and direction of propagation. The effects of particle sizes and layer thickness on vibration absorption are determined. The goal is to determine the required absorption characteristics as a function of particle size distribution, that is required to mitigate building vibrations.