A UNIFIED FAILURE ENVELOPE FOR ISOTROPIC FRESH WATER ICE AND ICEBERG ICE

摘要

A unified 3-D failure criterion for both isotropic fresh water ice and iceberg ice is presented. The need for such a general 3-D failure formulation stems from the fact that, during collisions of small icebergs with marine vehicles, ice at the ice-ship interface undergoes a complex state of deformation and stress before it fails and breaks away, and the use of the uniaxial strength of ice to compute impact loads may lead to inaccurate ice load calculations. The present failure criterion is developed on the basis of three different sources of experimental data. A total of about 300 triaxial tests were used, which covered a wide range of strain rates (10{sup}(-6)s{sup}(-1) to 10{sup}(-1)s{sup}(-1)), a wide range of confining stress (0.1 to 85 MPa), and a wide range of temperature (-1° to -45°C). The analysis of the results of all these tests demonstrate the existence of a unified failure envelope for both isotropic fresh water ice and iceberg ice.