To model cohesionless granular flow using continuum theory, the usual approach is to assume the cohesionless Coulomb-Mohr yield condition. However, this yield condition assumes that the angle of internal friction is constant, when according to experimental evidence for most powders the angle of internal friction is not constant along the yield locus, but decreases for decreasing normal stress c...

This paper investigates the force transmission modes, mainly described by probability density distributions, in non-cohesive dry and cohesive wet granular materials by discrete element modeling. The critical state force transmission patterns are focused on with the contact model effect being analyzed. By shearing relatively dense and loose dry specimens to the critical state in the conventional...

By pouring equal balls into a container one obtains disordered packings with fascinating properties which might shed light on several elusive properties of complex materials such as amorphous metals or colloids. In any real experiment with equal-sized spheres one cannot reach packing fractions (fraction of volume occupied by the spheres respect to the total volume, ρ) below the Random Loose Pac...

Thermally-assisted compaction of granular materials is of keen interest in many engineering applications. A proper estimation of the material behavior of compacted granular materials is contingent upon the knowledge of microstructure formation, which is highly dependent on the bulk material properties and processing conditions, during the deformation stage. Originating from the pair interaction...

A micromechanical study is made of the relationship between interparticle friction coefficient and macroscopic continuum friction and dissipation in idealised granular materials, using Discrete Element Method simulations with varying . As expected, macroscopic friction and dilatancy increase with . Surprisingly, dissipation is present even when or when . Hence, dissipation in idealised granular...

A microscopic framework for developing phenomenological constitutive models was recently developed for granular materials. The plastic strains are computed from relative sliding and rolling of particles, and the resulting microscopic theory is called the sliding-rolling theory. Within this framework, a phenomenological constitutive model was then developed to describe the anisotropic stress-str...

Reading and literature exploration are important tasks of scientific research. However, conventional retrieval systems provide limited support for these tasks by concentrating on identifying relevant materials. New generation systems should provide additional support functionality by focusing on analyzing and organizing the retrieved materials. A framework of literature exploration support syst...

I develop several new models that attempt to reproduce the structure of two-dimensional granular materials, and compare them with experiment using diagnostics from network science. I discuss one model that treats granular networks as a perturbation of a close-packed hexagonal lattice, and two models that are modifications of the random geometric graph (RGG). One of these modified RGGs simulates...

We probe the dependence of the low-velocity drag force in granular materials on the effective gravitational acceleration (g(eff)) through studies of spherical granular materials saturated within fluids of varying density. We vary g(eff) by a factor of 20, and we find that the granular drag is proportional to g(eff), i.e. that the granular drag, F(probe), on a vertical cylinder follows the expec...

Mesoscopic structures form in dense granular materials due to the self-organisation of the constituent particles. These structures have internal structural degrees of freedom in addition to the translational degree of freedom. The resultant granular elasticity, which exhibits intrinsic variations and inevitable relaxation, is a key quantity that accounts for macroscopic solid- or fluid-like pro...