Ice-Structure Interaction, IUTAM-IAHR Symposium, 14-17 August 1989, St. John's, Newfoundland
The deformation modes of polycrystalline ice are reviewed. Whereas single crystals of ice deform easily by shear on the basal plane, the minimum creep rate of polycrystalline ice is largely controlled by processes occurring on non-basal planes. Three main models describing the transient behaviour of polycrystalline ice are presented and discussed. Evidence that the occurrence of the first cracks, in the ductile-brittle transition, is related to a critical delayed elastic strain is presented. The mechanical behaviour of damaged ice is discussed. It is shown that damage enhances the creep rate notably.