2012/03/26 by Anne Dominique Cambou, Narayanan Menon · 1 citation
Physics and Astronomy · #cond-mat.soft
paper · pdf · doi:10.1073/pnas.1019192108
published as Cambou AD and Menon N (2011) Three-dimensional structure of a sheet crumpled into a ball PNAS 10:1073 · Accepted by the PNAS Editorial Board July 16, 2011 (received for review December 20, 2010)
arxiv created 2012/03/26 · arxiv updated 2012/03/28
When a thin sheet is crushed into a small three-dimensional volume, it invariably forms a structure with a low volume fraction but high resistance to further compression. Being a far-from-equilibrium process, forced crumpling is not necessarily amenable to a statistical description in which the parameters of the initially flat sheet and the final confinement fully specify the resulting crumpled state. Instead, the internal geometry and mechanical properties of the crumpled ball may reflect the history of its preparation. Our X-ray microtomography experiments reveal that the internal 3-dimensional geometry of a crumpled ball is in many respects isotropic and homogeneous. In these respects, crumpling recapitulates other classic nonequilibrium problems such as turbulence, where a system driven by long-wavelength, low-symmetry, forcing shows only rather subtle fingerprints of the forcing mechanism. However, we find local nematic ordering of the sheet into parallel stacks. The layering proceeds radially inwards from the outer surface. The extent of this layering increases with the volume fraction, or degree of compression.