Characterization of mesoscale instabilities in localized granular shear using digital image correlation |
| |
| Authors: | Amy L Rechenmacher Sara Abedi Olivier Chupin Andr??s D Orlando |
| |
| Institution: | (1) Department of Civil Engineering, University of Southern California, 3620 S. Vermont Ave, Los Angeles, CA 90089, USA;(2) LUNAM Universit?, IFSTTAR, IM, Structures, 44341 Bouguenais, France |
| |
| Abstract: | Within shear bands in sands, deformation is largely non-affine, stemming primarily from buckling of well-known force chains
and also from vortex-like structures. In the spirit of current trends toward multiscale modeling, understanding the links
between these mesoscale deformational entities and corresponding macroscale response will form the basis for the next generation
of sand behavioral models and may also aid in efforts to understand jamming–unjamming transitions in dense granular flows
in general. Experimental methods to quantify and characterize such subscale kinematics, in particular in real sands, will
play critical roles in these efforts. Digital Image Correlation (DIC) is a fast growing experimental technique to nondestructively
measure surface displacements from digital images. Here, DIC has been employed to identify and characterize the development
of vortex structures inside shear bands formed in dense sands during plane strain compression. A rigorous assessment of the
DIC method has been performed, in particular for subscale behavioral characterization in unbonded granular solids, and guidelines
are offered for accurate implementation. While DIC systematically overestimates shear band thickness, a methodology has been
devised to compensate for this overestimation. Shear band thickness for four different uniform sands were found to range between
6 and 9 grain diameters, and for a well-graded sand between 8 and 9.5 grain diameters. These determinations agree with visual
inspections of grain kinematics from the image data, as well as recent theoretical predictions. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
