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Granular Trip: Flying through the pore space of a sand specimen

This is a small sample of Hostun sand with D50 about 300 microns. This 3D image has been obtained with x-ray tomography (voxel size 15 microns). Credits: Jacques Desrues, Cino Viggiani, Edward Andò and Stephen Hall. (2013) Granular Trip: Flying through the pore space of a sand specimen. Further reading Andò, E., S.A. Hall, G.Continue reading “Granular Trip: Flying through the pore space of a sand specimen”

Triaxial shearing of sands using X-ray CT imaging and FEM

Triaxial shearing of an assembly of sand grains is numerically simulated using X-ray CT imaging and FEM concurrently. The actual morphology of particles, geometric contacts, and arrangement of solid, void phases are captured using X-ray CT imaging. A novel framework is introduced wherein a realistic assembly of sand grains is discretized using shell-based finite elementsContinue reading “Triaxial shearing of sands using X-ray CT imaging and FEM”

Stochastic Approach to the Solution of Boussinesq-Like Problems in Discrete Media.

A vertical surface load acting on a half-space made of discrete and elastic particles is supported by a network of force chains that changes with the specific realization of the packing. These force chains can be transformed into equivalent stress fields, but the obtained values are usually different from those predicted by the unique solutionContinue reading “Stochastic Approach to the Solution of Boussinesq-Like Problems in Discrete Media.”

A Cosserat Breakage Mechanics model for brittle granular media

Combining the Cosserat continuum with Breakage mechanics in a consistent thermodynamic way, offers substantial benefits to our capacity to model granular physics by accounting for both the entire grain size distribution, and its evolution. We provide an upscaling procedure that introduces material parameters accounting for the contribution of an evolving internal length representing the statisticsContinue reading “A Cosserat Breakage Mechanics model for brittle granular media”

Single particle breakage under uniaxial compression test

Single Leighton Buzzard sand particles were compressed uniaxially and two primary breakage modes were proposed: splitting and explosive. In the splitting mode, the particle breaks into two or three large pieces without the creation of numerous small fragments. In terms of force-displacement curve, it tends to be almost linear while the crack initiates and propagatesContinue reading “Single particle breakage under uniaxial compression test”

DEM Simulation of direct shear test

Image of evolution of particle displacements during DEM simulation of direct shear test on spherical particles Image of evolution of strong force chains during DEM simulation of direct shear test on spherical particles Credits: Cui and O’Sullivan., Géotechnique 56 (7), 455-468

Ricequakes

When brittle porous media interact with chemically active fluids, they may suddenly crumble. This has reportedly triggered the collapse of rockfill dams, sinkholes, and ice shelves. To study this problem, we use a surrogate experiment for the effect of fluid on rocks and ice involving a column of puffed rice partially soaked in a reservoirContinue reading “Ricequakes”

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