Study On Ship Ice Interaction Based On Elastoplastic Ice Constitutive Model

In recent years,climate warming has led to the continuous melting of polar sea ice,which has deepened the exploration of the Arctic navigation channel around the world.At the same time,the oil and gas,natural gas and other resources stored in the Arctic region have received continuous attention from various countries.However,at present,there are still a large number of icebergs and floating ice in the Arctic region,which pose a huge safety hazard to ships sailing in the polar region.The collision between sea ice and ships not only damages the structure of the ship itself,but also poses a threat to the safety of crew members in severe cases.The fuel leakage caused by the collision may also cause environmental pollution in the Arctic region.Therefore,the study of ship ice collision has very important theoretical and practical significance.In this paper,a finite element model of collision between polar ships and sea ice is established.The finite element software ABAQUS is used to numerically simulate the ice breaking process of ships under different working conditions,and the collision force and structural damage generated during the collision process are studied and analyzed.The physical and mechanical properties of polar sea ice are summarized.An elastic-plastic model is selected to simulate the mechanical properties of sea ice.A fully implicit graph return algorithm is used to update the stress.Tsai-Wu criteria and empirical failure criteria are used to describe the yield and failure of ice.Constitutive model codes are compiled and embedded in ABAQUS software for subsequent numerical simulations.A uniaxial compression test of ice was conducted,and the experimental data were compared with the numerical simulation results to verify the accuracy of the selected ice material model.The applicability of the ice material model in numerical simulation is further verified by combining the numerical simulation of ice triaxial compression and ship ice collision model tests.The ice layer has a temperature gradient from top to bottom.The constitutive models of sea ice at different temperatures are assigned to the numerical model.Based on the finite element software ABAQUS,the problem of ship ice collision under different operating conditions is further studied.The influence of initial pore size on ship ice collision results was studied from two aspects: pore content and pore distribution location.The variation rules of collision force and bow damage deformation were analyzed under different collision velocities,bow angles,and bow shapes.The results show that the initial porosity of sea ice greatly reduces the stiffness and strength of sea ice,and reduces the damage to ships compared to flat ice;With the increase of ship speed,the ship ice collision force increases nonlinearly,and the degree of ice layer damage and hull damage increases;The collision force on the hull increases with the increase of the inclination angle of the bow column;When the ship’s speed is 10 m/s,the ice breaking ability of the ice breaking bow and the flying shear bow is superior to other shapes of the ship’s bow.Finally,considering that the icebreaker will bear cyclic loads most of the time during navigation,the fatigue analysis of the bow structure under cyclic ice loads is conducted based on the combined speed ice thickness condition,and the maximum damage values of the bow under different conditions are obtained.The results of this study can provide a reference basis for the structural design and optimization of polar ships to a certain extent.