Length Scales for Nonaffine Deformation in Localized, Granular Shear
We offer experimental observations of meso-scale deformation and kinematic activity within sheared granular layers to investigate the nature and spatial periodicity of nonaffine displacement fields within shear bands in a granular material. Prismatic specimens of sands and glass beads are subjected to plane strain deformation in which zero-strain conditions are enforced by translucent glass walls. We use the Digital Image Correlation (DIC) to track movements of small, overlapping particle clusters. By subtracting a superimposed first-order shear displacement field from the observed non-affine displacement fields, co-rotational vortices appear and coordinate with previously-observed kinematic patterns. We undertake a preliminary assessment of the spatial periodicity of such patterns to glimpse the nature of an underlying length scale for granular material deformation.
KeywordsGranular material Shear bands Non-affine deformation Vortices Length scales
The authors would like to thank the National Science Foundation (grant CMMI-0748284), USC and the USC WiSE program for their financial support of this research.
- S. Abedi, A.L. Rechenmacher, I. Faoro, Vortex structures inside shear bands in sands, in Proceedings Geo-Frontiers 2011, Dallas, TX, 13–16 Mar 2011Google Scholar
- O. Chupin, A. Rechenmacher, S. Abedi, Finite strain analysis of non-uniform deformations inside shear bands in sands. Int. J. Numer. Anal. Methods Geomech. (2011) [in press]Google Scholar
- B. Utter, R.P. Behringer, Experimental measures of affine and nonaffine deformation in granular shear. Phys. Rev. Lett. 100(20), 208302–1–4 (2008)Google Scholar