Author(s): T. Karna; K. Kamesaki; H. Tsukuda
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Keywords: No Keywords
Abstract: This paper addresses problems of ice load determination in conditions where an ice floe acts on a vertical offshore structure. The ice sheet is assumed to fail by crushing and flaking. This failure mode yields the largest global ice loads. Furthermore, dynamic amplification of the internal stresses due to steady-state vibrations may arise if this ice failure mode prevails. Results of several test series are first used to get a new insight to the flaking failure of an ice sheet. Horizontal cracks emanating form the ice edge appear to be a central phenomenon to be considered. Recent tests have revealed that a large amount of energy is dissipated at the ice edge at the incipient loading phase. This phenomenon explains the rapid decay of the transient structural vibration, which occurs in quasi-static conditions after a major event of ice failure. A new layered model for the near field area of the ice edge was derived to account for this decay. The model is incorporated in a computer program for dynamic ice-structure interaction. The predicted structural response is compared with a test results.
Year: 1998