MODELING VISCOPLASTIC BEHAVIOR OF ANISOTROPIC POLYCRYSTALLINE ICE WITH A SELF-CONSISTENT APPROACH

A ViscoPlastic Self-Consistent (VPSC) model has been applied to polycr ystalline ice in order to characterize the relation between the textur e of the material and the instantaneous anisotropic mechanical behavio r. We assume that ice crystals deform by basal, prismatic, and pyramid al slip. The resistance of these slip systems is determined by an inve rse approach, based on the comparison between model results and result s of several mechanical tests. The VPSC model well reproduces all expe rimental macroscopic behavior only if we introduce a small-but not neg ligible-amount of pyramidal slip, which is not observed experimentally . The introduction of this probably unrealistic slip system possibly c orrects the errors linked to the assumptions of the model, that we dis cuss. We finally use the model to describe the behavior of some typica l polar ices in relation to the symmetries of the texture. (C) 1997 Ac ta Metallurgica Inc.