title: Entangled granular media.
abstract: We study the geometrically induced cohesion of ensembles of granular "u particles" that mechanically entangle through particle interpenetration. We vary the length-to-width ratio l/w of the u particles and form them into freestanding vertical columns. In a laboratory experiment, we monitor the response of the columns to sinusoidal vibration (with peak acceleration Γ). Column collapse occurs in a characteristic time τ which follows the relation τ∝exp(Γ/Δ). Δ resembles an activation energy and is maximal at intermediate l/w. A simulation reveals that optimal strength results from competition between packing and entanglement.
authors.affiliation: School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
authors.forename: Nick
authors.initials: N
authors.lastname: Gravish
authors.forename: Scott V
authors.initials: SV
authors.lastname: Franklin
authors.forename: David L
authors.initials: DL
authors.lastname: Hu
authors.forename: Daniel I
authors.initials: DI
authors.lastname: Goldman
mesh_terms: D008956:Models, Chemical; D009010:Monte Carlo Method