Effect of particle shape in packing of faceted particles.
By: Raúl Cruz
From: Universidad de Navarra
At: Instituto de Investigação Interdisciplinar, Anfiteatro
[2012-06-12]
In this seminar, I will present experimental and numerical results of the effect that particle shape has on the packing properties of granular materials. We have systematically measured the particle angular distribution, the cluster size distribution and the stress profiles of ensembles of faceted elongated particles deposited in a bidimensional box. We also explore the effect of the filling mechanism; modifying the feeding rate of the grains by varying the volume fraction of the initial configuration from which the grains are deposited. Increasing the initial volume fraction results in an enhancement of the disorder in the final deposit. Consequently, it leads to a decrease of the final packing fraction and a reduction of the number of particles oriented with their diagonal in the direction of gravity. However, for very high initial volume fractions, the final packing fraction is increased again. This implies that two deposits with the same final packing fraction  can be obtained from very different initial conditions. Then the structural properties are analysed revealing that, although the global morphology of both deposits seem to be similar, their mechanical properties notably differs. We will also present experimental and numerical results of the effect that a partial discharge has on the morphological and micro-mechanical properties of the silo. The comparison of the particle orientation after filling the silo and its subsequent partial discharge reveals important shear induced morphological changes, which affects the stress propagation.