Author(s): D. M. Masterson; D. E. Nevel; R. C. Johnson; J. J. Kenny; P. A. Spencer
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Abstract: During the fall and winter of 1983/84 a major research project was undertaken by the Hibernia Partners (Mobil, Chevron, Gulf and Petro-Canada) to simulate the interaction of an iceberg impacting an offshore structure. The tests investigated local pressure vs. area effects during iceberg impacts under highly controlled conditions. The 21 iceberg impact simulation tests were performed in four (4) tunnels dug into an iceberg grounded off the Hamlet of Pond Inlet, N. W. T. Two separate ice testing systems were required to accommodate the range of indentor areas which were 0.02 m2,0. 1 m2,0. 5 m2,1 m2 and 3 m2. Four actuators acting in parallel were required to generate a force of 18 MN or 4,000,000 lbs. Impact velocity was initially 100 mm/s and a servo control system regulated the velocity during the tests. Plots of ice pressure vs. area indicated that contact area affects the ice pressure, with the average pressure decreasing as contact area increases. In the larger 1m2 and 3 m2 tests, dynamic effects were observed which caused a sawtooth waveform with a frequency of the order of 15 Hz to be superimposed on the force vs. time plot. The amplitude of the waveform was often 1/2 of the peak load at that point. The waveform was determined not to be caused by the servo control system and resulted from the failure mechanisms within the ice.
Year: 1992