Creep, failure and fracture of ice

Hamza, Hany El-sayed (1981) Creep, failure and fracture of ice. Doctoral (PhD) thesis, Memorial University of Newfoundland.

[English] PDF (Migrated (PDF/A Conversion) from original format: (application/pdf)) - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (23MB) [English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. (Original Version)

Abstract

A finite element creep bending model has been developed using thick plate theory. The model agrees very well with numerical creep models and with field data collected during a load bearing capacity test of fresh-water ice. A simple numerical formula is derived which can predict the time of the onset of failure using the critical strain energy as a failure criterion. This formula agrees very well with available field data. -- An algorithm has been developed which is able to predict the viscoelastic response of ice under different uniaxial loading conditions. This algorithm has been generalized using the finite element method to predict the viscoelastic response due to multiaxial loading. The general finite element model is capable of solving the ice cover - offshore structure interaction problem. A similar procedure has been used to predict the viscoelastic response of the cracked three-point bend test specimen due to constant cross-head speed loading. -- The linear and non-linear fracture toughness of artificially grown fresh-water ice has been determined during a small-scale experimental program. The effect of rate of loading, test temperature, specimen dimensions, and grain size on fracture toughness has been investigated. -- Finally, the strain rate dependent, critical strain energy per unit volume has been proposed as a failure criterion for ice under different loading rates. The criterion is applicable to ice failure during a laboratory test and failure of ice covers due to interaction with an offshore structure or due to supporting a load for short or long periods of time.

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