Numerical Simulation Of Interaction Between Floating Offshore Platform And Sea Ice

As the Arctic development again to be in the rising,the research and development of newly polar ships and offshore platform equipment has again become a hot topic.In addition to the capacity of personnel and equipment anti-freezing measurements,polar ocean equipment should also be able to cope with the threat of the floating ice floes and even large icebergs that long-term exist on the sea surface.Therefore,reasonable determination of ice loads that acting on the structure is one of the most basic requirement for the design of polar ice structure.As most of the existing polar offshore platforms are fixed platforms or bottom-mounted platforms,it is of great significance and value to calculate the ice load of floating ice-resistant offshore platforms that can operate in arctic deep sea areas and move flexibly.In this paper,the interaction between structures and sea ice is simulated by commercial finite element software LS-DYNA,and the ice loads of level ice and broken ice acting on the floating platform are calculated respectively according to the common sea ice types in the arctic region.Cohesive element method was used to simulate the fracture of level ice to numerically calculate the ice force on the KULLUK platform.The reliability of the selected ice parameters and the applicability of this numerical model to simulate the large scale inverted cone structure subjected to level ice action were verified by comparing the model test data.Then,the North Dragon semi-submersible platform was used as the parent ship to add inverted cone parts on its pillars.The ice loads of single pillar at different cone angles,column forms and orientations werecalculated and the dimensionless coefficient k(ratio of total ice force to single pillar ice force)was explored under different orientations.The last part of this paper numerically simulate the interaction between the North Dragon semi-submersible platform and the broken ice field to explore the relationship between ice force and different parameters including orientations,ice drift speed and ice floe sizes.