Investigating granular friction through vibration

Dalton, F.¹

¹Istituto dei Sistemi Complessi, Italy

We perform experiments on a granular medium confined to a circular channel. The medium is excited both by the shearing action of a forced annular overhead plate and by vertical excitation. The vibration naturally causes the granular structure to lose rigidity and here we attempt to quantify what level of energy input is necessary to weaken the granular material.  The results indicate that an extremely low level of vibration is sufficient to completely destroy the solidified state of the GM, though we find that one requires a much larger vibration to significantly reduce the viscosity of the resultant granular fluid.