Elastic energy and relaxation in triaxial compressions

Abstract

For a quasi-statically sheared granular system, the deformation of individual particles leads to reversible energy storage that sustains elastic stress. But, the system would subsequently relax because particles jiggle and slide. By employing the complete continuum mechanical theory, also known as Granular Solid Hydrodynamics (GSH), the elastic energy and its relaxation (denoted by granular temperature) are both calculated and explained. For a dense assembly, it is found that the elastic energy and energy dissipation rate reach peak values simultaneously, as it reaches peak strength. To observe the mesoscale characteristics, a two-dimension biaxial test is simulated with a discrete element method. The motion of particles and the evolution of force networks are exhibited at different strain values. The discrete element simulations results are helpful to understand GSH results.