MECHANICAL PROPERTIES OF ELLIPTIC MICROSTRUCTURE FORMED IN GRANULAR MATERIALS

Abstract

The elliptic structure composed of particles aligned in an elliptic circle in granular material is recognized as a unit of microstructure. The mechanical properties of this elliptic structure are examined in the two-dimensional condition. Based on the contact forces between the constituent particles calculated from equilibrium, stability is presented as a function of the shape of the elliptic structure and the stress condition surrounding the structure. The deformation behavior given as the compliance matrix is also examined, based on shell theory and the theory of micropolar elasticity. It was found that some characteristic mechanical properties of a granular material, such as deformation anisotropy, dilatancy and non-coaxiality, can be explained by the elliptic structure, where the rotation of the constituent particles plays an important role.