Publications [#245419] of Robert P. Behringer

Papers Published
  1. Clark, AH; Petersen, AJ; Kondic, L; Behringer, RP, Nonlinear force propagation during granular impact., Physical Review Letters, vol. 114 no. 14 (April, 2015), pp. 144502 [doi] .

    We experimentally study nonlinear force propagation into granular material during impact from an intruder, and we explain our observations in terms of the nonlinear grain-scale force relation. Using high-speed video and photoelastic particles, we determine the speed and spatial structure of the force response just after impact. We show that these quantities depend on a dimensionless parameter, M^{'}=t_{c}v_{0}/d, where v_{0} is the intruder speed at impact, d is the particle diameter, and t_{c} is the collision time for a pair of grains impacting at relative speed v_{0}. The experiments access a large range of M^{'} by using particles of three different materials. When M^{'}≪1, force propagation is chainlike with a speed, v_{f}, satisfying v_{f}∝d/t_{c}. For larger M^{'}, the force response becomes spatially dense and the force propagation speed departs from v_{f}∝d/t_{c}, corresponding to collective stiffening of a strongly compressed packing of grains.