Time Domain Study On The Interaction Between Sea Ice And Mooring Structures In Polar Environment

Under the continuous effect of greenhouse effect,the polar ice cover area is gradually shrinking,and the Arctic waterway is gradually opened.The exploitation of oil and gas resources in the Arctic area is gradually valued by more and more large oil companies.The Arctic is becoming another hot land after the Middle East.The exploration,acquisition,storage and transportation of oil and gas resources in the Arctic region will bring a huge demand for the marine equipment suitable for polar operations,followed by higher requirements for the design,development and safe operation of polar marine equipment.The dynamic simulation of the interaction between offshore structures and sea ice has always been the focus and difficulty of scholars at home and abroad,which is embodied in the complexity of physical and mechanical properties of sea ice,the difficulty of accurate calculation of ice load,and the difficulty of coupling simulation of mooring system structure sea ice.Based on the idealized hypothesis of the interaction process between sea ice and structures,combined with the multi-body numerical simulation method,the complete process of the interaction between sea ice and structures is simulated.The motion response of moored ship,cylindrical drilling platform and four column semi-submersible under the action of sea ice is studied.First of all,this paper puts forward the idealized hypothesis of the interaction process between sea ice and structure.On this basis,it analyzes the forces in each stage of the interaction process between sea ice and structure,summarizes the forces and calculation formulas in each stage of the interaction process between sea ice and structure,and provides theoretical support for the construction and application of subsequent numerical simulation programs.Then,the interaction process between ice breaking and moored ship is simulated.By using the discrete element method,the resistance of the ship under the condition of ice coming from the bow and different speed points is calculated,and compared with the experimental results.Based on the quasi-static method,the ice load under different angles is applied to the mooring ship as an external load.The influence of different single point mooring position on the overall response of the mooring ship is analyzed,and the sensitivity analysis of the effect of the thickness of crushed ice on the response of the mooring ship is made.Finally,the interaction between sea ice and floating structure is simulated.After verifying the accuracy of the numerical program,the influence of different parameters of the structure and sea ice on the interaction process between the flat ice and the structure is explored.Based on the above research results,the quasi-static method and the secondary development function of the mooring analysis software of offshore structures are used to study the response of structures under the action of sea ice in the mooring state.The research objects include cylindrical drilling platform and four column semi-submersible.In the simulation process,the ice load of each column,the total ice load,the three degrees of freedom movement of the structure and the tension of the anchor chain are mainly concerned,which provides a reasonable reference for the safe operation evaluation of the polar mooring structure.