Rim curvature anomaly in thin conical sheets revisited
arXiv:1105.1366 · doi:10.1103/PhysRevE.84.066603
Abstract
This paper revisits one of the puzzling behaviors in a developable cone (d-cone), the shape obtained by pushing a thin sheet into a circular container of radius by a distance [E. Cerda, S. Chaieb, F. Melo, and L. Mahadevan, {\sl Nature} {\bf 401}, 46 (1999)]. The mean curvature was reported to vanish at the rim where the d-cone is supported [T. Liang and T. A. Witten, {\sl Phys. Rev. E} {\bf 73}, 046604 (2006)]. We investigate the ratio of the two principal curvatures versus sheet thickness over a wider dynamic range than was used previously, holding and fixed. Instead of tending towards 1 as suggested by previous work, the ratio scales as . Thus the mean curvature does not vanish for very thin sheets as previously claimed. Moreover, we find that the normalized rim profile of radial curvature in a d-cone is identical to that in a "c-cone" which is made by pushing a regular cone into a circular container. In both c-cones and d-cones, the ratio of the principal curvatures at the rim scales as , where is the pushing force and is the Young's modulus. Scaling arguments and analytical solutions confirm the numerical results.
25 pages, 12 figures. Added references. Corrected typos. Results unchanged