Strength criteria at anisotropic principal directions expressed in closed form by interparticle parameters for elliptical particle assembly.

Using a microstructural mechanics approach, the close-packed elliptical particle assembly is first represented by a lattice model that is described by a beam system, and the Mohr–Coulomb (MC) shear failure criterion is used to describe the contact (beam) breakage. Through structural mechanics analysis of the unit cell, macroscopic strength criteria and associated parameters at two anisotropic principal directions are expressed in closed form with respect to the particle shape and microscopic strength parameters while considering the successive breakage of contacts. The macroscopic failure characteristics of elliptical particle assemblies are described by the MC failure criterion, and the macro–micro relations of strength parameters can be directly determined by the proposed expressions. The proposed analytical expressions are confirmed to be accurate due to the good consistency between theoretical and discrete element method (DEM) results based on the regular arrangement. The introduction of the fabric anisotropy parameter extends the applicability of the theoretical results to irregular arrangement cases, and the deviation with more realistic particle assemblies is investigated. The proposed expressions of the macroscopic strength parameters can help us better understand the influence of inherent anisotropy and microscopic properties and provide an alternative approach to determine the microscopic parameters in DEM simulations. [ABSTRACT FROM AUTHOR]