Research On Force Mechanism Of Ship Impacting On Pier With Different Shapes

During the ship collision study of a certain bridge,it was found that the impact force of the square pier,round end shaped pier,and tip-shaped pier during the collision process has a very large range of change,which fully shows that the influence of pier shape on the impact force is very significant.Therefore,it is necessary to conduct in-depth research.Based on a certain bridge,the paper uses Hyper Mesh,a large grid division software,and LS-DYNA,an explicit dynamic analysis program,to establish a bridge crash numerical simulation analysis model to study the impact of different pier shape on ship collision force under the same impact conditions,and further study force mechanism of piers with different shapes during impact process.The main research work is as follows:(1)Set up square piers,round piers,round end piers and tip-shaped piers of different widths to explore the effect of the width of different shape piers on the impact force,and analyze the force mechanism of the impact process from the relationship between the pier width and the contact surface stiffness.The study shows that with the increase of the width of the pier,the impact force of the pier is increased.Among them,the width of the square pier has a great impact on the impact force,the widths of the circular pier and round end pier have little impact on the impact force,and the width of the tip-shaped pier has minimal impact on the impact force.(2)Build rectangular piers,round end piers and tip-shaped piers with the same width of impact moment in the same direction of impact.Discuss the impact of piers of different shapes on the impact force,and analyze the force mechanism of the impact process from the perspective of the initial contact surface stiffness and the contact surface stiffness change process.The study shows that the shape of the pier has a great impact on the impact force,and the impact force on the rectangular pier is the largest,while the round end shaped pier and the point-shaped piers can effectively reduce the rigidity of the contact surface of the stern,thereby reducing the impact force.(3)The round end shaped piers with different round end diameters and the end-point piers with different tip angles with the same bending moment in the same direction of impact are established respectively,and the influence of different round end diameters and different tip angles on the impact force is discussed.Studies have shown that the smaller the diameter of the round end and the smaller the angle of the tip,the more the stiffness of the contact surface is reduced,so that the impact force is smaller.Can provide a reference for the pier selection.(4)The difference between the impact force of solid and hollow piers,the difference of impact force of bridge piers with different concrete strengths,and the impact force of bridge piers with different reinforcement ratios are compared.The research shows that the three kinds of comparisons all change the flexural rigidity of the bridge piers.Under the same impact force,the deformation of piers slightly changes.However,during the collision between the ship and the bare pier,the deformation of the pier is relatively small compared to the stern,and the impact force is mainly determined by the stiffness of the stern contact surface,so the impact is not significant.Can provide a reference for the design of the pier.