Study On Collision Between Ship And Bridge Superstructures For Explicit Dynamic Of ABAQUS

At present,China's water transportation ship transportation is developing rapidly to large scale,high speed and strong power.However,for some completed bridges,the designed navigation standards and clearance are relatively small due to the shipping conditions at that time,which cannot satisfy the current transport channel traffic requirements.In addition,ships are driven into non-navigable holes due to the misjudgment of ship operators,which brings about frequent collisions of ships with bridge superstructure.At the moment,there are many researches on the ship impacting the lower part of the bridge,while there are less researches on the ship impacting the upper part of the bridge.For this reason,this paper concludes the current research status of ship-bridge collision,ship-bridge collision theory and its simplified calculation methods,makes a conclusion on the calculation methods of ship-bridge collision in national codes.Based on the nonlinear finite element numerical simulation of ship-to-bridge superstructure,this paper mainly discusses the influence of ship tonnage,collision speed,collision angle girder,collision height,area stirrup ratio and girder form on the collision process.The main conclusions reached are as follows:1.In this paper,Through the energy analysis of the collision process,it is found that the pseudo-strain energy accounts for less than 7% of the total energy of the system,which indicates that the pseudo-artificial energy of the system is small and using ABAQUS/Explicit in the calculation results are reliable.2.Numerical simulation of the second ship collision accident of Hukeng Bridge is obtained: The bridge deck concrete between the side beam and the secondary side beam was compressed plastically in a large area.The bridge deck concrete above all the main girder beam ribs was under high pressure stress,which resulted in a compression damage zone along the longitudinal direction of the whole bridge.Tensile plastic damage mainly occurs above and near the transverse beam,along the transverse direction of the bridge;Plastic damage occurs in more than 90% of bridge deck concrete area,which should be laid stress on to in design.The numerical simulation results are consistent with the damage characteristics of the accident bridge.3.The paper compares the maximum ship collision forces between different main girders and obtains the order of ship collision forces: T-beam < box girder < hollow slab,the maximum impact force of t-beam is about 2.03 MN,box girder is 6.66 MN,hollow slab is 7.97 MN,hollow slab is 4 times of T-beam.4.The paper adopts the orthogonal test analysis method to establish the orthogonal test with 5 factors and 5 levels of ship tonnage,ship speed,collision angle,collision position and area stirrup ratio.The number of tests is only 0.8% of the overall test plan.It adopts orthogonal test which can be significantly reduced the number of tests.Through the extreme difference analysis and variance analysis of the test results,it is obtained: The main influencing factors of the resultant impact force are ship speed,collision height and ship tonnage,while collision angle and girder area have little influence.However,the main factors of tangential impact force are the impact angle,ship speed,area stirrup ratio,ship tonnage,while the impact height is not significant.The area stirrup ratio has great effect on the impact of tangential ship,which is because of the increase of the hoop,the shear stiffness of the cross-sectional bridge is greatly increased.