Effect of contact anisotropy on the crushing strength of aggregates

LUNAM Université, IFSTTAR, MAST, GPEM, F-44340 Bouguenais, France

^* e-mail: aurelien.neveu@ifsttar.fr
^** e-mail: riccardo.artoni@ifsttar.fr
^*** e-mail: yannick.descantes@ifsttar.fr
^**** e-mail: patrick.richard@ifsttar.fr

Published online: 30 June 2017

Abstract

This work deals with the effect of the contact orientation distribution on the crushing of granular materials. At first, a simple drop weight experiment was designed in order to study the effect of the location of three contact edges on the fracture pattern and the strength of a model cylindrical particle. The sample was placed on two bottom contact edges symmetrically distributed with reference to the vertical symmetry plane of the particle and subjected to an impact at the top. Angle α between the plane connecting a bottom contact edge to the centerline of the cylinder and a vertical plane was varied. The energy required to fracture the particle was shown to be an increasing function of angle α. Peculiar crack patterns were also observed. Then, we present a discrete model of grain fracture [1] and employ it for a numerical analysis of the problem. The cylindrical particle is discretized by means of a space filling Voronoi tessellation, and submitted to a compression test for different values of angle α. In agreement with experiments, simulations predict a strong effect of the contact orientation on the strength of the particle as well as similar fracture patterns. The proposed numerical model is therefore an interesting tool for understanding fracture mechanisms with the purpose of optimizing the crushing process.