CRACK-PROPAGATION AND FRACTURE-RESISTANCE IN SALINE ICE

Crack propagation in saline ice (a model sea ice) is investigated in t his study in an attempt to understand the processes of crack growth at one loading rate and two temperatures. As has been previously observe d in cold sea ice and warm or cold fresh-water ice, crack growth occur s in initiation/arrest increments. The energetic stability criteria of crack growth are examined in saline ice and crack growth is character ized in terms of the fracture-resistance parameter K-R. This paper off ers the development of a new fracture geometry capable of sustained st able crack growth and the presentation of fracture-resistance curves f or 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 e xtension; (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.