Entangled granular media

Phys Rev Lett. 2012 May 18;108(20):208001. doi: 10.1103/PhysRevLett.108.208001. Epub 2012 May 17.


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.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Models, Chemical*
  • Monte Carlo Method