Granular impact and the critical packing state
arXiv:1007.2695 · doi:10.1103/PhysRevE.82.010301
Abstract
Impact dynamics during collisions of spheres with granular media reveal a pronounced and non-trivial dependence on volume fraction ϕ. Post impact crater morphology identifies the critical packing state ϕ_{cps}, where sheared grains neither dilate nor consolidate, and indicates an associated change in spatial response. Current phenomenological models fail to capture the observed impact force for most ϕ; only near ϕ_{cps} is force separable into additive terms linear in depth and quadratic in velocity. At fixed depth the quadratic drag coefficient decreases (increases) with depth for ϕ< ϕ_{cps} (ϕ> ϕ_{cps}). At fixed low velocity, depth dependence of force shows a Janssen-type exponential response with a length scale that decreases with increasing ϕ; and is nearly constant for ϕ> ϕ_{cps}.
References in corpus (6)
- Unified force law for granular impact cratering
- Scaling and dynamics of sphere and disk impact into granular media
- Onset of mechanical stability in random packings of frictional spheres
- Dynamics of shallow impact cratering
- Projectile interactions in granular impact cratering
- Phase transition in a static granular system