Study On Prediction Of Ship' Icebreaking Resistance And Structural Response Considering Fluid-Structure Interaction

In recent years,the development of Arctic resources and the construction of related Arctic routes have become hot issues in the world.For China,under the "the Belt and Road" strategy,the elaborate "Polar Silk Road" can not only greatly reduce the cost and time of conventional maritime transportation,but also greatly enhance China's influence on international trade.As ships are increasingly transported and explored in polar ice-covered waters,the demand for icebreakers and polar ship markets with icebreaking capabilities is bound to increase.At present,although most scholars have conducted related research on ship-ice collision by constant mass method and fluid-structure interaction,only a few studies have focused on the difference between the constant mass method and the fluid-structure interaction method relative to the icebreaker icebreaking process and structural damage.At the same time,there is a lack of a method to effectively predict bow extreme stress for an icebreaker.Based on the above reasons,this paper studies the ship ice breaking resistance prediction based on empirical formula and ALE fluid-structure coupling algorithm.On the other hand,it studies the structural response and extreme stress of the icebreaker bow considering water foundation.The main works of this paper are as follows:(1)Ice load calculation studies based on different methods are performed.It mainly summarizes the formation and classification of sea ice and its physical and mechanical properties.At the same time,the failure mode of ice when the ship icebreaking is sorted out,and the ice load of the icebreaker under different ice-breaking scenes is compared and analyzed by using different calculation models.(2)The application of fluid-structure coupling algorithm in ship-ice collision is researched.Some basic principles of the ALE algorithm in the nonlinear finite element software LS-DYNA are described,and the appropriate ice materials are selected and verified.Finally,to verify the applicability of the method in the ship-ice collision simulation,the numerical simulation and model test of the collision between the ice body and the hull plate in the water medium are compared.(3)Study on ice resistance prediction of ship-icebreaking considering water foundation.Firstly,the ice resistance of the icebreaker is estimated based on different empirical formula models,and then the sensitivity analysis of the main parameters in each empirical formula is carried out.Finally,based on the ALE algorithm,the ice resistance of the icebreaker in the water medium is numerically simulated,and empirical formulas and numerical simulation of the ice resistance are compared to verify the applicability and accuracy of the ice resistance prediction.(4)Study on the structural response of the icebreaker bow and prediction of the extreme stresses in water medium.Firstly,based on the fluid-structure interaction method,the numerical simulation of ship icebreaking is carried out,and the influence of fluid field on the icebreaker's bow is analyzed.Then,compared with the damage deformation,partial pressure and impact force of the icebreaker's bow calculated by the additional mass method,to reveal the influence of the water medium on the ship's icebreaking process.Finally,based on the numerical simulation results and the Naess-Gaidai tail extrapolation method to predict the extreme stress for icebreaker bow.