| As polar glaciers begin to melt,opening of the arctic shipping lanes will be on the horizon.The Arctic Council of Iceland in 2004 pointed out: that the Arctic will be one of the main places for maritime transport in the coming decades of oil and gas exploration and development in "the human development report".In January 2018,the Chinese government issued a White Paper on China’s Arctic Policy to contribute Chinese wisdom and Chinese strength to the development of the polar region.On one hand,the arctic channel opening has become inevitable.On the other hand,floating ice in channel and travelling of an iceberg constitutes great threat to ordinary transport ships sailing in the sea area.It brings the probability of ship collision with floating ice or level ice.At present,the ship-water-ice collision in the study of water medium is usually the collision of the water medium as the“attached water quality” into the ship-ice collision.Based on this,the water medium is further refined into the hull.The collision surface is pre-stressed to decouple the ship-water-ice coupling.Therefore,the study on dynamic response of ship ice collision under water is of great significance for improving the structural safety of polar vessels.The main work of this paper is as follows:(1)Research on simplified calculation method of influence of water medium on pre-pressure during ship-ice collision.Dynamic grid technology is used for the numerical simulation study.Based on RANS equations and improved two-phase flow fluid volume function(VOF)model,by changing the relative velocity and impact angle between hull and ice.The pressure at bow and the change free surface are forecast during the whole process of ship approaching to ice.The relation ship between the pressure and velocity as well as angle are found,the influence of the water medium produced by the full coupling of ship-water-ice on the ship ice collision load is simplified as pre-loading on the collision surface of the hull to achieve the purpose of decoupling,and the ship-ice numerical simulation is performed for the whole process.Provide accurate load input.(2)Comparison of surface pre-pressure model test and numerical simulation in ship-ice approaching process.Model test,by changing the hull-ice relative velocity and impact angle,is used to measure stem surface pressure for two objects in the process of approaching to each other.The results measured will be compared with the results of numerical simulationcalculation.It is to verify the accuracy of the numerical simulation method.Which forms a foundation for study of dynamic response in the following.(3)Dynamic response study of hull structure under ship-ice collision.Comparing three constitutive models of ice materials studied by domestic and foreign scholars,the constitutive model of the ice materials used in the numerical simulation is obtained through the experiments of rigid walls impacted by the circular table ice.Based on the previous studies,the coupling problem among ship,water,and ice during the ship-ice collision process is simplified by pre-adding the pressure on the collision surface of the hull to the collision problem between the ship and the ice.Firstly,the pre-filling water pressure is considered during the ship-ice collision is compared.Secondly,on the basis of considering the pre-water pressure,the ship-ice collision structure response under different working conditions was performed.The hull structure in ice damage deformation under impact load,structure stress and energy absorbing structure response law and mechanical properties are required to be well known. |
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