A micro-mechanical connection between the single-particle strength and the bulk strength of random packings of spherical particles

Abstract With a view to obtaining a fundamental insight into the attrition taking place in packings of spherical particles, a so-called distinct element method has been used to simulate numerically the bulk behaviour of brittle granular material as a function of the single-particle properties. This ‘computational physics’ approach has been confirmed to give a good simulation of the mechanical behaviour of particle assemblies on a micro-level by local photo-elastic stress and strain measurements. For our purpose, the single-particle Side Crushing Strength (SCS) distribution of the spheres under investigation was connected with the so-called Bulk Crushing Strength (BCS) and Shear Resistance (ShR) of the material. The simulation results for both the BCS and the ShR tests show a good agreement with actual experiments. In the BCS test, the influence of the interparticle friction coefficient is not very outspoken due to the fact that the particles hardly move with respect to one another during compression. In the ShR simulations, the interparticle friction coefficient strongly influences the amount of breakage due to the large amount of particle movement. In both types of test, the influence of shape and position of the input SCS-distribution can be easily evaluated, and is found to be considerable. It is concluded that the distinct element approach is a valuable tool in coupling single-particle and bulk-particle tests.