| Abstract | Segmented indentors were used to conduct identation tests using urea model ice. Each segment of an indentor was supported on three load cells to enable measurement of force generated in that segment as a result of interaction with ice. Tests were conducted using 3, 5 or 7 segments. The range of ice thickness was between 40 and 81 mm, and the rate of indentation was between 2 and 400 mm s super minus super 1. The results are presented as time-history plots of forces across each segment as well as the whole width of an indentor. The main result of these tests is that the effective pressure measured during tests at low indentation rate was higher than that at high indentation rate. The force-time plots indicate that there was simultaneous failure of ice on all segments at low indentation rates and that there was nonsimultaneous failure of ice at high rates of indentation. This behavior is attributed to brittle, flaking failure at high indentation rates. Spectral analysis of force data indicates that most of the power is contained at frequencies of less than 5 Hz. The peaks in the ice force records fit a Weibull probability distribution. |
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