A benchmark for particle shape dependence

Abstract

A study on the effect of particle shape and fragmentation on the mechanical behavior of granular materials using discrete element method AIP Conference Proceedings 1542, 915 (2013) Abstract. Particle shape is a major parameter for the space-filling and strength properties of granular materials. For a systematic investigation of shape effect, a numerical benchmark test was set up within a collaborative group using different numerical methods and particles of various shape characteristics such as elongation, angularity and nonconvexity. Extensive 2D shear simulations were performed in this framework and the shear strength and packing fraction were compared for different shapes. We show that the results may be analyzed in terms of a low-order shape parameter η describing the degree of distortion from a perfectly circular shape. In particular, the shear strength is an increasing function of η with nearly the same trend for all shapes, the differences being of second order compared to η. We also observe a nontrivial behavior of packing fraction which, for all our simulated shapes, increases with η from the random close packing fraction for disks, reaches a peak considerably higher than that for disks, and subsequently declines as η is further increased. Finally, the analysis of contact forces for the same value of η leads to very similar statistics regardless of our specific particle shapes.

FEM×DEM multi‐scale model for cemented granular materials: Inter‐ and intra‐granular cracking induced strain localisation

“…In addition, the non‐regular shape of the meso‐grains also appears to increase the maximum shear strength. This is consistent with previous studies of the influence of the grain shape on the mechanical behaviour of dense assemblies of cohesionless particles 68,69 …”

Sample preparation of dense granular materials Influence of void ratio e and coordination number Z* on the mechanical behaviour at failure

“…It can be noticed that whatever the value of µ s , ⌧/ n for samples A and B are equivalent once > 0.15. This is consistent with the observations made by many authors: for large strains, once the permanent strength regime reached, the internal state variables that characterize the initial state (isotropic) no longer control the mechanical behaviour -the resistance of the samples is then mainly controlled by the particle shapes and marginally by the intergranular friction coe cient [11].…”