Probing Shear Stress Distribution within Single Particle Scale inside Particulate Packing

Abstract

Studies have been performed to understand the nature of stress distribution within birefringent sensor particles embedded inside a granular bed under axial compression loading. Both the variation of the maximum shear stress and the direction of the major principal stress within single particle scale are analysed with respect to the proximity of particles to the wall boundaries of the compression chamber. The study shows that for an increase in the loading intensity, multiple interactions of contacts result in non-homogeneous distribution of maximum shear stress within sensor particles. The ability of the particles to sustain maximum shear stress depends on how closely these reside with respect to wall boundaries. These results imply that the applicability of present contact interaction laws used in advanced simulation methods such as the Discrete Element Method (DEM) for modelling the mechanical behaviour of micro and nano particulate assemblies could be limited and needs to be revised. This is because DEM modelling is normally based on the assumption that the interaction behaviour of a given particle contact is independent of what happens at its neighbouring contacts. Though further studies are required, the current research is a step towards attaining a clear understanding of the mechanical response of particulate materials under industrial process loading conditions which is rather complex as of now.