Results published in 2012 in Acta Geotechnica
For the first time, the researchers from the 3SR lab were able to observe the motion of fifty thousand sand particles in 3D using x-ray micro-tomography.
Each particle in the sample is identified by its 3D geometry, and its kinematics (translation and rotation) are measured at every 1% shortening of the sample (around 0.22 mm) while it is deformed. This technique opens the way towards the understanding of strain localization and global deformation in granular materials through the dynamics occurring at the particle scale.
3D view from x-ray microtomography of a granular assembly (grey-scale) overlayed with measured 3D grain rotation angles (colour-scale) during axial loading
Andò E, Hall S A, Viggiani G, Desrues J, Bésuelle P (2012) Grain-scale experimental investigation of localised deformation in sand: a discrete particle tracking approach. Acta Geotechnica.