Research Objectives:
The goal of this research is to investigate the breakup process of antarctic sea ice in light of recent findings indicating that the fracture strength of first-year ice is strongly size dependent, that the deformation and fracture on the scale of tens of meters is influenced by microstructural anisotropy, and that the characteristic flaws of sea ice (such as brine drainage features) give rise to length scales relevant to transitions in fracture behavior. There is an urgent need to investigate the fracture behavior of warm McMurdo Sound sea ice, given its operational importance with regard to research and tourism at McMurdo Station.
Important topics to be investigated include coupled deformation-diffusion influences on the fracture of sea ice (due to fluid transport within the ice matrix), the influence of loading rate versus specimen size on the fracture behavior, fractal descriptions of the failure surfaces, and a new cyclic loading geometry that should benefit the constitutive measurements. These findings will give important insight into the underlying mechanisms of ice breakup and will significantly improve the reliability of models of this process. This work will improve the understanding of and ability to model the deformation and fracture of Antarctic sea ice at scales applicable to the breakup of ice sheets.
Typically the ice in McMurdo Sound nearest to McMurdo Station is thick multi-year ice. North of this multi-year ice, out as far as Cape Royds typically, mixed ice conditions are to be expected, including trash ice, platelet ice, pressure ridging, and rafted ice. The objective for the field test portion of this project is to be located well north of this mixed ice, on newly-formed thin ice that has not been trashed or ridged. Project team members will search for the requisite sea ice conditions along a path midway between the cutter channel and the McMurdo-Cape Royds path.
