Open AccessDeformation field in indentation of a granular ensemble
Author(s) -
Tejas G. Murthy,
Ebenezer P. Gnanamanickam,
Srinivasan Chandrasekar
Publication year - 2012
Publication title -
physical review. e, statistical, nonlinear and soft matter physics
Language(s) - English
Resource type - Journals
eISSN - 1550-2376
pISSN - 1539-3755
DOI - 10.1103/physreve.85.061306
Subject(s) - indentation , materials science , deformation (meteorology) , flow (mathematics) , granular material , characterization (materials science) , vector field , strain rate , mechanics , velocity gradient , vortex , field (mathematics) , geometry , optics , composite material , physics , mathematics , nanotechnology , pure mathematics
An experimental study has been made of the flow field in indentation of a model granular material. A granular ensemble composed of spherical sand particles with average size of 0.4 mm is indented with a flat ended punch under plane-strain conditions. The region around the indenter is imaged in situ using a high-speed charge-coupled device (CCD) imaging system. By applying a hybrid image analysis technique to image sequences of the indentation, flow parameters such as velocity, velocity gradient, and strain rate are measured at high resolution. The measurements have enabled characterization of the main features of the flow such as dead material zones, velocity jumps, localization of deformation, and regions of highly rotational flow resembling vortices. Implications for validation of theoretical analyses and applications are discussed