Rate Effects in the Compaction of Brittle Granular Materials

Under quasistatic loading, brittle granular materials compact through a process of comminution, whereby a reduction in particle size facilitates more efficient packing allowing for a reduction in porosity with a minimal increase in the elastic strain energy in the material. Under dynamic loading, comminution is limited by finite crack propagation velocity and inertial resistance to granular flow. We investigate this phenomena using new methods for mesoscale simulation and in-situ x-ray imaging of granular compaction. Implications on continuum constitutive model development are discussed.