Engineering Properties of Sea Ice

Abstract

As the continental shelves of the Arctic become important as source areas for the oil and minerals required by human society, sea ice becomes an increasing challenge to engineers. The present paper starts with a consideration of the different fields of engineering which require information on sea ice with the tasks ranging from the design of ice-breaking ships to Arctic drilling platforms and man-made ice islands. Then the structure of sea ice is described as it influences the observed variations in physical properties. Next the status of our knowledge of the physical properties important to engineering is reviewed. Properties discussed include mechanical properties (compressive, tensile, shear and flexural strengths; dynamic and static elastic moduli; Poisson’s ratio), friction and adhesion, thermal properties (specific and latent heats, thermal conductivity and diffusivity, density) and finally electromagnetic properties (dielectric permittivity and loss, resistivity). Particular attention is given to parameters such as temperature, strain-rate, brine volume, and loading direction as they affect property variations. Gaps, contradictions in the data, and inadequacies in testing techniques are pointed out. Finally suggestions are made for future research, especially for more basic laboratory studies designed to provide the data base upon which further theoretical developments as well as field studies can be built.

Ice, Cloud, and land Elevation Satellite (ICESat) over Arctic sea ice: Retrieval of freeboard

“…In the conversion to ice freeboard, the uncertainty in bulk density is a significant source of error as it varies by over 15% between 1 m and 3 m thickness. In the second approach, we use a mean density and vary it over a range, i.e., ρ i = 0.915 ± 0.01 g/cm 3 [ Weeks and Lee , 1958; Schwarz and Weeks , 1977].…”

Brittle Failure of Ice

“…2b;Michel 1978;Sinha 1982) and can be characterized (σ ∝ ε m e mQ RT ) by a strain-rate sensitivity factor, m, which, although dependent upon stress-state and texture (Manley and Schulson 1997), is usually taken to be m ~ 0.3, and by an apparent activation energy, Q, which ranges between 45 kJ/mol and 90 kJ/mol (Weertman 1983). The "peak" stress decreases with increasing salinity/porosity (Peyton 1966;Schwarz and Weeks 1977), but exhibits little dependence upon grain size (Schulson and Cannon 1984;Cole 1985Cole , 1987. Within this regime, dislocation processes are at play (Duval et al 1983): basal glide serves as the major strain-producing mechanism, dislocation climb accounts for strain-rate hardening, both directional and non-directional interactions account for strain hardening, and internal cracking and dynamic recrystal-lization account for strain softening (Duval et al 1983;Cole 1987).…”

The mechanical properties of sea ice — A compilation of available data

“…it is recognized that other surveys on sea ice have been compiled before (Weeks and Assur 1967;Mellor 1983;Michel 1978, chapt. 2;Schwarz and Weeks 1977).…”