Dissipative dynamics of granular media investigated by forced torsion pendulum
Institut de Génie Atomique, Ecole Polytechnique
Fédérale de Lausanne CH-1015 Lausanne, Switzerland
Accepted: 19 May 2000
The oscillating probe of a low-frequency (1 Hz) forced torsion pendulum is immersed into a granular medium, and the dynamic moduli are measured. A first layer of grains is firmly fixed to the probe surface. The energy losses of the system are determined by the statistical properties of force-chains opposing the rotation of the pendulum. The position of the observed loss peak is found to be quadratically dependent on the radius and on the depth of immersion of a cylindrical probe, and proportional to the coefficient of static friction between the grains. The logarithmic moisture-induced ageing effect is also observed.
PACS: 46.55.+d – Tribology and mechanical contacts / 45.70.-n – Granular systems / 81.05.Rm – Porous materials; granular materials
© EDP Sciences, 2000