Cooling after shearing: three possible fates for dense granular materials

Abstract We perform discrete element simulations of freely cooling, dense granular materials, previously sheared at a constant rate. Particles are identical, frictional spheres interacting via linear springs and dashpots the solid volume fraction is equal to 60% during both shearing cooling. measure average distributions contacts per particle anisotropy contact network. observe that material, beginning can be shear-jammed, fragile or unjammed. The initial state determines subsequent evolution assembly into either an anisotropic solid, isotropic fluid, respectively. While solids fluids rapidly reach apparent final steady configuration, microstructure continues evolve for fluids. explain this with presence vortices in flow field counteract randomizing structure-annihilating effect collisions. notice, accordance previous findings, mechanically stable particles permits distinguish between unjammed states and, therefore, determine beforehand fate evolving materials. also find one-to-one relation number particle. latter is, variable must incorporated continuum models even case states, where it was widely accepted sufficient describe geometry system.