Ice islands are extensive tabular icebergs that calve from Arctic ice shelves and floating glacier tongues. As they drift south, they deteriorate by melting and edge-wasting, but they can also fracture, which results in the calving of large fragments from the parent ice island. Fracture events may be related to several factors; however, the buoyancy force associated with underwater rams can yield enough bending stress to cause ice failure. We tested this hypothesis by developing a 3D numerical model using finite element analysis (FEA) model. The model is based on classical theory of solid mechanics and calculates stress across the free-floating ice island as it is subjected to gravitational and buoyancy forces. The model was successfully validated against analytical solutions of a semi-infinite beam-on-elastic foundation theory and an idealized simple beam model. An element erosion technique with a strength-based failure criterion (500 kPa) was employed to simulate fracture initiation and propagation. The results indicate that the buoyancy force from the underwater ram can break the ice island in flexure when the maximum principal stress exceeds the failure criterion. We assessed fracture behaviour of three ice island fragments or icebergs with known geometries. We aim to incorporate our FEA into a comprehensive ice island deterioration model that considers melting, and edge-wasting processes. This model can then be used for ice hazard management in relation to offshore infrastructure and shipping.

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25th International Conference on Port and Ocean Engineering under Arctic Conditions, POAC 2019
Department of Geography and Environmental Studies

Sazidy, M. (Mahmud), Crocker, G. (Greg), & Mueller, D. (2019). A 3d numerical model of ice island calving due to buoyancydriven flexure. In Proceedings of the International Conference on Port and Ocean Engineering under Arctic Conditions, POAC.