Measuring order in the isotropic packing of elastic rods
Laboratoire de Physique Statistique, Ecole Normale Supérieure, UPMC Paris 06, Université Paris Diderot, CNRS 24 rue Lhomond, 75005 Paris, France, EU
2 Department of Physics, McGill University, 3600 University - Montréal (QC) H3A 2T8, Canada
3 RDP, ENS Lyon - 46 allée d'Italie, 69007 Lyon, France, EU
Accepted: 13 June 2011
The packing of elastic bodies has emerged as a paradigm for the study of macroscopic disordered systems. However, progress is hampered by the lack of controlled experiments. Here we consider a model experiment for the isotropic two-dimensional confinement of a rod by a central force. We seek to measure how ordered is a folded configuration and we identify two key quantities. A geometrical characterization is given by the number of superposed layers in the configuration. Using temporal modulations of the confining force, we probe the mechanical properties of the configuration and we define and measure its effective susceptibility. These two quantities may be used to build a statistical framework for packed elastic systems.
PACS: 46.32.+x – Static buckling and instability / 46.70.Hg – Membranes, rods, and strings / 61.43.-j – Disordered solids
© EPLA, 2011