Interaction of grain morphology and intergranular friction on grain packing†

The bulk density of loosely packed grains is determined by grain morphology and the intergranular friction coefficient. Creating simulated grain packings with realistic packing densities is the first step in performing predictions of granular material behavior at higher compaction stresses. Our novel approach performs jamming simulations at near-zero pressure where the surface properties are decoupled from the elastic properties to explore the interaction between grain morphology and intergranular friction. We use bonded particle model (BPM) grain representations with different subparticle resolutions to vary their morphological properties. Our investigation uses both regular- and irregular-shaped BPM grains to develop a relationship between grain morphology, intergranular friction, and the jamming limit that applies to simulated and physical grains. The relationship prescribes a friction coefficient for use in simulations of grain packing that considers the effect of morphology.