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MECHANICAL PROPERTIES OF FRESH WATER ICE

Most strength values, cited in the literature, for fresh water ice are not well defined in terms of the type of ice or strain rate applied, and therefore their usefulness for engineering purposes is questionable. In this study the uniaxial strength of various ice types was determined over a wide range of strain rates and stresses. The ice types chosen for this study columnar ice, snow ice, and frozen frazil slush, represent the three most common distinctive types found in the stable ice cover of rivers and lakes. All columnar ice was chosen with a global c-axis (major crystallographic axis) distribution tending to a preferred horizontal orientation, as illustrated on a stereographic (Wulff) net. The grain size was of the order of 0.5 cm in diameter. The snow ice had equiaxed grains with an average diameter of 0.1 cm, and the frozen frazil slush had irregular grain shapes with an average diameter of 0.1 cm. The crystallographic orientation for snow ice and frozen frazil slush was random. Two types of tests were used--tensile and compression. Tensile tests, using constant loads, were carried out to the point where cylindrical samples failed or a secondary creep rate was obtained. This can be considered as a constant stress test since ice has no necking tendencies. Compression tests were performed under constant strain rate conditions. The yield point was taken as the critical value for the analysis. The stress and strain rate behaviour was also studied in the temperature range minus 1.5 to minus 35 C. The curves have been extended by using: a) low stress data (Bromer and Kingery) for columnar ice; b) low stress data (Tabor and Walker) for snow ice; c) high strain rate data (Carter) for snow ice. The strain rate-stress curve was divided into two regions--the ductile and brittle region. In terms of stress the ductile region was further divided into the low, intermediate, and high stress stages. The latter stage was typified by formation of cracks whereas the intermediate stress stage lacked these characteristics. The brittle region consisted of a ductile-brittle transition zone which showed a decreasing stress with an increasing strain rate; it eventually became independent of the stress in the quasi-brittle region. The results now available cover a range of ten orders of magnitude for the strain rate and over two orders of magnitude for the stress. The transition from one zone or region to another depends on temperature. In the intermediate stress stage, the strain rate at a constant stress varied as much as one order of magnitude for the different ice types. Frozen frazil slush had the lowest strain rate; it was followed by snow ice, then by columnar ice. This difference was caused by the apparent elastic modulus. The curves of the three ice types were brought into coincidence by dividing the stress by the apparent elastic modulus. The resultant strain rate-stress curves represented most strain rates which are encountered in engineering studies involving interaction with fresh water ice.

  • Supplemental Notes:
    • Abstract of paper delivered at the First International Conference on "Port and Ocean Engineering under Arctic Conditions" held at Trondheim, Norway, August 23-30, 1971
  • Corporate Authors:

    POAC Conference

    ,    
  • Authors:
    • Ramseier, R O
  • Publication Date: 1971

Subject/Index Terms

Filing Info

  • Accession Number: 00025697
  • Record Type: Publication
  • Source Agency: Arctic Institute of North America
  • Files: TRIS
  • Created Date: Mar 28 1972 12:00AM