Study On Numerical Simulation Of Ship-bridge Collision Under Fluid-structure Interaction

In engineering practice,ship-bridge collision in a fluid environment such as a river or a bay is a very typical fluid-structure interaction problems.The instantaneous force caused by the ship-bridge collision will cause the ship to generate a motion response and change the flow field around the collision area.At the same time,this change in return put an effect on the movement and deformation of ships,which causes the fluid-structure interaction effect between the ship-bridge structure and the surrounding water.Domestic and overseas scholars have done a lot of research work on the ship-bridge collision problems.However,due to the limitation of calculation conditions,Many researchers consider the interaction of fluid and ship-bridge structure in the form of ship’s additional mass.At the same time,the impact of the ship’s continuous power and the surrounding fluid environment is rarely considered during the collision.This method reduces the accuracy of numerical simulation to a certain extent.In this paper,based on the existing ship-bridge collision related drawings and data,this paper takes the characteristic ship type of 3300 T in the Three Gorges Reservoir area as the research object.The author uses the additional mass method and the fluid-structure interaction method to establish the ship collision bridge model,and the collision model of the propulsive ship is established on the basis of considering the effect of water flow.In this process,a more detailed study was conducted on the interaction between the fluid and the ship during the collision,the structural response of the ship,and the factors affecting the collision force of the ship-bridge.The fluid-structure interaction model of ship-bridge collision that considers water weight,flow velocity,and ship propulsion further improves the existing research,and the series of conclusions drawn can also provide theoretical support for the optimal design of ship structure.In this paper,the main research work is as follows,(1)The author conducted a simulation study of the impact process of the 3300 T characteristic ship in the Three Gorges Reservoir area in the additional mass method and the fluid-structure interaction method.The author makes a comparative analysis of the change trend of the ship-bridge collision force curve in the additional mass method and fluid-structure interaction method.The quantitative relationship between the additional coefficient and the peak value of the collision force was also explored.In addition,The author makes a detailed analysis of the collision force curve under two types of models and the structural damage and deformation of the ship and the applicability of the method.(2)The author uses different initial speeds of the ship as the research conditions to explore the impact of speed on the ship-bridge collision.The research shows that the greater the initial speed,the more severe the damage to the ship structure;Using different collision scenarios as working conditions,the impact of the collision scenarios on the collision process was analyzed,and it was found that the structural damage caused by the frontal impact is more serious than the side impact;Using different draught as working conditions,the impact of ship draught on the collision process is analyzed.It is concluded that the deeper the draught,the higher the quality of the attached water of the ship,the greater the impact on the collision process,and the more serious damage to the ship structure.(3)Considering the joint effects of ship propulsion and different flow regimes during the entire collision process,the author selected three flow regimes of counter current,still water,and downstream based on simulation of ship thrust,and carried out simulation analysis of ship-bridge collision process,comparing the damage degree of the structure under various working conditions.In addition,the effects of different river flow patterns on the ship-bridge collision process are also studied.In addition,the influence of different river flow patterns on the ship-bridge collision process is also studied,and the quantitative relationship between the relative speed of the ship-bridge collision and the peak force of the collision is analyzed.