Analysis Of Ship Collision Response Of Long-Span Suspension Bridge

Inland river fleet transport efficiency is higher than single ship transport,but the push fleet system energy is huge,once out of control hit the bridge,it is bound to lead to inestimable losses.In order to explore the response of the large fleet after hitting the bridge pier and the difference between the large fleet and the single ship hitting the bridge pier,the relevant numerical simulation should be carried out.In this thesis,based on the Huangjueping Yangtze River Bridge,the finite element analysis method is used to analyze the response of the bridge under the impact of a single ship or fleet.The main work and conclusions are as follows:(1)According to the bridge design documents,combined with the geological,hydrological,ship conditions and navigation conditions at the bridge address,the calculation parameters of the ship collision condition of the bridge are obtained,including:ship collision calculation water level,calculation speed,ship tonnage and accessibility.Combined with the bridge tower and foundation form,the single ship and fleet impact simulation is carried out for the Z2 main tower,which is the most disadvantageous part of the bridge.(2)The shape of the main tower of the bridge is strange,the structure is complex,and the structure discretization is very difficult.in addition,the impact calculation process has the characteristics of high nonlinearity and slow calculation speed,so it is difficult to shorten the calculation time on the premise of ensuring accuracy.In this thesis,the impact part is divided in detail when dividing the unit,which ensures that the main tower unit is continuous,strictly controls the minimum size of the unit,and avoids the unit deformity at the same time,after a large number of unit adjustment,optimization and trial calculation process,the calculation time is effectively shortened,and the calculation results are reliable.Through analysis and calculation,the collision force time-history curve,energy change,bridge tower response and ship response after the flat bow and spherical bow ship hit the bridge tower are obtained respectively,and the differences and reasons in the process of collision between flat bow ship and ball bow ship are compared and analyzed.(3)There is little research on the impact of the fleet on the bridge in the inland waterway,and there is still a blank in the research on the impact of the large fleet on the bridge.This thesis makes a complete study on the impact of the large fleet on the bridge for the first time.First of all,consult the relevant data of the inland river fleet,on-the-spot investigation of the connection mode between ships on the Yangtze River,adopt the safety principle of "breaking on collision,ships scattered and open" to the ship-to-ship binding system,and fully simulate the fleet binding effect by using the rich material library of LSDYNA.Secondly,after the completion of the fleet model assembly,the forward collision between the middle ship and the side ship is studied according to the most unfavorable situation.Finally,through calculation and analysis,the time-history curve of ship impact force,energy change,bridge tower response and ship response under the two impact modes are obtained respectively,and the characteristics of each stage of fleet impact on bridge tower are analyzed.the results show that the impact force of large fleet is not much higher than that of single ship.(4)Based on the analysis of the results of the fleet hitting the bridge tower and the statistics of the energy value of each ship in the fleet and its percentage in the total energy,it can be known that most of the kinetic energy is absorbed by the bow deformation after the single ship hits the bridge tower.Most of the kinetic energy remains unchanged,and the energy absorbed by bow deformation is relatively small.It is concluded that although the large fleet has great kinetic energy compared with the single ship,under the action of a reasonable binding system,most of the ships in the fleet can keep a larger speed and disperse,except those that directly hit the bridge tower.the rest of the ships lost less or were not impacted.(5)The impact force of the bridge under the impact of a single ship or fleet is applied to the MIDAS model of the bridge,the calculation and analysis under accidental load is carried out,and the accidental combination of the limit state of bearing capacity with the results of other actions of the bridge is carried out to verify the safety of the bridge under the action of ship collision force and other loads.