Author(s): Devinder S. Sodhi

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Abstract: The first part of the paper reviews some of the experimental work on ice-structure inter­action. The review includes small-scale and medium-scale indentation tests conducted to under­stand this interaction and to measure the effective pressures at different speeds and contact areas. Different modes of ice failure have been identified, such as ductile failure, ductile flaking and brittle flaking. Experiments to understand brittle flaking were conducted in the laboratory to observe the ice-structure interaction and to measure pressure in different parts ofthe indentor. It was found that the contact between the indentor and the ice failing during brittle flaking is over a small area of contact. Such small areas of contact were also observed in the ship-ice interaction. In the second part of the paper, a description of the indentation test using a segmented indentor and freshwater ice is given. Each segment of the indentor was supported on three load cells to measure force during an interaction. The results of these tests show that there is simultaneous development of effective pressure on all segments at low indentation velocities because of ductile failure of ice. At high indentation velocities, there is random variation of force during an interaction, and the variations in interaction force about the mean force decrease with increas­ing speed. This is attributed to brittle flaking of ice and results in considerably less effective pressure on the indentor. To compare results of indentation tests done at different scales. it is suggested that a simi­larity principle from "replica" modeling be adopted. In replica modeling, the indentation tests are done at a scale smaller than full-scale using the same material and the same indentation speed as in full scale. Using this similarity principle, the effective pressure measured in small-scale indentation tests in freshwater ice is found to be in the range of pressures measured on large structures in the field.

DOI:

Year: 1992