The effect of ice floe shape on the load experienced by vertical-sided structures interacting with a broken ice field

Abstract

Abstract In this study, numerical experiments are conducted to investigate the effect of ice floe shape on the load experienced by vertical-sided structures interacting with a broken ice field. We create numerical ice fields with different floe shapes and otherwise identical properties. These fields are used to simulate ice-structure interaction with vertical-sided structures. First, we investigate the effect of floe shape in ice-tank tests by comparing the numerical results to the ice tank test results. Then, we conduct a sensitivity study to investigate the correlation between the floe shape effect and other parameters. The primary finding is that the ice floe shape has a large influence on the mean and standard deviation of the ice load in interaction scenarios dominated by ice accumulation and clearance around the structure. In particular, square floes, which are often used in ice tank tests, result in higher mean loads and standard deviations than other floe shapes. The simulation results show that the greater length and higher stability of force chains is the primary mechanism causing the floe shape effect. The floe shape effect is exacerbated in confined conditions, where the force chains may cause bridging between the structure and a rigid boundary. The presence and length of ‘parallel opposite edges’ is an important factor influencing the floe shape effect. This result is novel compared to earlier studies, which only consider body ‘roundness’ or ‘angularity’ in assessing shape effects. We demonstrate the importance of using accurate floe shapes in ice tank tests and in discrete element method (DEM) modelling of broken ice-structure interaction scenarios.