Sat, 26 Jul 2008 07:26:14 BST CiteULike: kdesmond's Bernstein http://www.citeulike.org/user/kdesmond/author/Bernstein CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/kdesmond/article/2747288 <i>Nature, Vol. 427, No. 6974. (5 February 2004), pp. 503-504.</i> Stress propagation: Getting to the bottom of a granular medium Matthew Stone David Bernstein Rachel Barry Matthew Pelc Yee-Kin Tsui Peter Schiffer doi:10.1038/427503a Nature, Vol. 427, No. 6974. (5 February 2004), pp. 503-504. 2008-05-03T00:07:18-00:00 2004 Nature 427 6974 503 504 granular_impact qualifier http://www.citeulike.org/user/kdesmond/article/2563945 <i>Physical Review E, Vol. 70, No. 4. (29 October 2004), 041301.</i><br /><br />We present a series of measurements examining the penetration force required to push a flat plate vertically through a dense granular medium; focusing in particular on the effects of the bottom boundary of the vessel containing the medium. Our data demonstrate that the penetration force near the bottom is strongly affected by the surface properties of the bottom boundary; even many grain diameters above the bottom. Furthermore; the data indicate an intrinsic length scale for the interaction of the penetrating plate with the vessel bottom via the medium. This length scale; which corresponds to the extent of local jamming induced by the penetrating plate; has a square root dependence both upon the plate radius and the ambient granular stress near the bottom boundary; but it is independent of penetration velocity and grain diameter. Local jamming via penetration of a granular medium MB Stone R Barry DP Bernstein MD Pelc YK Tsui P Schiffer doi:10.1103/PhysRevE.70.041301 Physical Review E, Vol. 70, No. 4. (29 October 2004), 041301. 2008-03-19T18:41:36-00:00 2004 Physical Review E 70 4 041301 American Physical Society jamming qual qualifier