Mechanical characterization of jammable granular systems

Abstract

The mode by which a granular material can transition between fluid-like and solid-like states has been often referred to as jamming. The use of this property (via vacuum pressure) for engineering applications has only recently been explored. Several possible applications are presented. However, thorough characterization of mechanical properties and material selection for jammed systems has not been reported. Glass beads of differing size distributions, silica blasting media, sand, and ground coffee were tested under different vacuum pressures in a procedure similar to an unconsolidated-undrained triaxial compression test for soils. Coffee was found to have the highest strength to weight ratio. Literature predictions of the trend between applied pressure and effective Young' modulus was also investigated.