Ice-induced vibrations of model structures with various dynamic properties

Abstract

For the design of offshore structures in regions with ice-infested waters, the prediction of interaction between floating level ice and the support structure is essential. If the structure is vertically sided at the ice-structure interface and certain ice and structural conditions exist, then the phenomenon known as ice-induced vibrations can develop. Recently, an ice-structure interaction model has been developed and validation has been attempted based on dedicated experiments. This study extends the validation by investigating the capabilities of the analytical model in predicting the indentation speed range for the frequency lock-in regime of ice-induced vibrations with various input parameters. Implementation of these various input parameters seeks to address the challenge of adapting the analytical model from the reference input parameters to scenarios with other structural properties. Using these various input parameters, the analytical model can demonstrate accurate prediction of frequency lock-in vibrations as observed in the experiments when the mean global ice load in crushing is properly estimated. For the cases when the mean global ice load was not properly estimated, either unsuitable scaling between input parameters, undesirable behavior of the model ice during the experiments, or a combination thereof may be the cause. Overall, this study serves to establish the range of applicability for the analytical model in terms of accurate prediction of frequency lock-in vibrations between model ice and various structures and discusses the sensitivity of the analytical model with respect to the input parameters. This study is an important step towards application of the analytical model for full-scale scenarios.