Micromechanical prediction of the compressive failure of ice: numerical simulations

Abstract

Abstract The brittle compressive failure of polycrystalline ice is studied in this paper with a micromechanical model developed by Wu and Niu [1995, Mech. Mater. 20, 9–32]. Using physically definable parameters, the failure stresses and the effective compliances are predicted for several microstructures generated from a graph model. It is shown that (i) the uniaxial and biaxial compressive strengths are strongly dependent on the intrinsic heterogeneities with a scatter between 25–80% of the mean values, (ii) neither the critical crack density nor a critical damage measure based on the effective compliance concept are suitable phenomenological failure parameters, (iii) crack-crack interactions play a major role in statistical compressive fracture although the critical crack densities satisfy a weak interaction assumption, (iv) a change in failure mode can be indicated by relative changes in the effective compliance components, (v) the effective compliance is strongly anisotropic under compression and its scatter due to microstructural variations is less than that of the peak stress, (vi) the failure strains decrease with increase in the grain size, but increase with increase: in the friction coefficient, and (vii) the volumetric strains at failure are generally small and may have a grain size dependence.