Attenuation of external vibrations transmitted into platforms by granular media for special applications

Mitigation of mechanical vibrations from external sources into structures by granular media is investigated to prevent transmission into the structure by surrounding granular media layers. Mechanical properties of granular media can be selected for absorption of specific frequency band of external vibrations. The absorption frequency band of the granular media can be move by design to required frequency band where scattering and dissipation of vibrational energy is maximized. Samples of granular media layers are subjected to external vibrations of different intensity and frequency. Experimental values are presented for attenuation versus frequency for different layers of selected grain sizes, at audible frequencies. The goal is to determine media properties that maximize vibration attenuation for special applications of vibration free platform for such specialized application as supports for atomic force microscopy supports and more recent gravitational-wave detectors.