CRACK-PROPAGATION AND FRACTURE-RESISTANCE IN SALINE ICE

Crack propagation in saline ice (a model sea ice) is investigated in this study in an attempt to understand the processes of crack growth at one loading rate and two temperatures. As has been previously observed in cold sea ice and warm or cold fresh-water ice, crack growth occurs in initiation/arrest increments. The energetic stability criteria of crack growth are examined in saline ice and crack growth is characterized in terms of the fracture-resistance parameter K-R. This paper offers the development of a new fracture geometry capable of sustained stable crack growth and the presentation of fracture-resistance curves for saline ice at -25 degrees and -15 degrees C. The important findings of this paper are that: (i) in warm saline ice, extensive local crack-tip damage is accompanied by a limited amount of slow, stable crack extension; (ii) fracture in cold saline ice is characterized by locally negative K-R behavior; and (iii) fracture in cold or warm saline ice is characterized by globally positive K-R curve behavior.