Author(s): Ase Ervik; Knut V. Hoyland; Aleksey Marchenko; Marina Karulina; Evgeny Kaulin
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Abstract: The objective of the work presented in this article was to investigate the vertical stress distribution of first year sea ice covers; especially the tensile strength was compared to the flexural strength (beam capacity). For this work two scientific expeditions on sea ice were designed and executed; respectively to the Svea bay and travelling by ship (RV Lance) in the Barents sea. The ice examined in Svea was cold and brittle, showing a clear temperature gradient, while the ice examined on Lance was nearly isothermal and ductile. The experimental work consisted of; cantilever beam tests, small scale horizontal uni-axial compression tests as well as temperature and salinity measurements. Small scale uni-axial compression tests suggested that the vertical profile of the elastic modulus, E (z), was similar to the temperature profile (at least when salinities were similar). From these experiments; a non-linear stress distribution, σ (x, z), was derived for the cold brittle Svea ice, by linear elastic failure theory and a non-linear vertical elastic modulus profile, E (z). For warm ice we assumed a linear elastic perfect-plastic material with constant E (z). These failure models predicted a pronounced temperature variation in tensile strength compared to the flexural strength which was observed to vary far less with temperature. Also, the effect of the water foundation on the predicted beam momentum was analyzed by the Winkler foundation, the inclusion gave minor changes to the predicted stress.
Year: 2014