title: Footprints in sand: the response of a granular material to local perturbations.
abstract: We experimentally determine ensemble-averaged responses of granular packings to point forces, and we compare these results to recent models for force propagation in a granular material. We use 2D granular arrays consisting of photoelastic particles: either disks or pentagons, thus spanning the range from ordered to disordered packings. A key finding is that spatial ordering of the particles is a key factor in the force response. Ordered packings have a propagative component that does not occur in disordered packings.
authors.affiliation: Department of Physics and Center for Nonlinear and Complex Systems, Duke University, Durham, North Carolina 27708-0305, USA.
authors.forename: J
authors.initials: J
authors.lastname: Geng
authors.forename: D
authors.initials: D
authors.lastname: Howell
authors.forename: E
authors.initials: E
authors.lastname: Longhi
authors.forename: R P
authors.initials: RP
authors.lastname: Behringer
authors.forename: G
authors.initials: G
authors.lastname: Reydellet
authors.forename: L
authors.initials: L
authors.lastname: Vanel
authors.forename: E
authors.initials: E
authors.lastname: Clément
authors.forename: S
authors.initials: S
authors.lastname: Luding