Insights on the pressure distributions of controlled ice-induced vibration experiments

Increased need for energy pushed offshore wind, oil, and gas companies into deeper waters in the Arctic and Subarctic regions, bringing extra challenges with it. It is observed that dynamic interaction between the offshore structure and floating ice sheet might result in ice-induced vibrations, which can contribute to fatigue damage. To better understand this complex phenomenon, forced ice-induced vibration experiments are carried out in the ice tank at the Hamburg Ship Model Basin (HSVA), Hamburg, Germany. In the tests, different rigid structures are forced through the still ice by systematically changing the ice speed. Pressure distributions in the ice-structure interface and resulting structural motions are analyzed using two multivariate analysis methods: 1) proper orthogonal decomposition and 2) smooth orthogonal decomposition. Results indicate that both methods capture the dominant pressure variations successfully and result responses that are physically interpretable. For example, first pressure mode illustrates the ductile pressure variation on the structure, which varies in the ice drift direction, and some combinations of second and third pressure modes represent the oscillations in the cross-flow direction, which illustrate the complex nature of ice-induced vibrations.