Finite Element Analysis Of Changshan Bridge Collision By Ship

With the rapid development of science,technology and economy,the construction of large-scale river-crossing bridges and sea-crossing bridges has stepped into a new developing stage.For the bridges built over busy rivers and straits,there may occur many accidents such as ship collision,causing damage or even collapse to the bridge.Once the ship-bridge collision takes place,it not only causes harm to people’s lives and property,but brings great inconvenience to people’s traffic due to the damage of the bridge.In order to be able to timely repair and reinforce the bridge after the collision damage,it is quite necessary to look into the damage mechanism in ship-bridge collision and proceed with right assessment on the damage status.As the physical test is almost impossible to implement,the computer software has been the main use of the current method.In this paper,Ls-dyna,a general nonlinear finite element software,has been adopted for numerical simulation analysis of ship-bridge collision,comparing the results under different impact conditions,analyzing the damage status of the bridge pier and the bearing capacity after collision.By hierarchical fuzzy comprehensive analysis method,carry out damage assessment the collided bridge,to provide scientific basis for the following repair and reinforcement work.The specific research contents are as follows:(1)This article,through the analysis of domestic and foreign ship bridge collision accidents,specific to project case,puts forward the purpose and significance of this subject study,and introduces the basic principle and method of the finite element simulation collision,as well as makes detailed description for the key problems which should be noticed in the research process and numerical simulation method.(2)The modeling is established based on Changshan bridge,and then set up different element models for the different structures of bridge,to analyze the influence of pile-soil effect on the collision results,and to study the differences and application range between the three calculation models of ship collision single pier,ship collision full bridge and rigid body ship collision full bridge.Through the finite element numerical calculation,select the model of whole ship and whole bridge as the model of this numerical calculation,and on this basis,carry on the follow-up calculation and analysis.(3)Under the circumstance of being familiar with the research purpose and research theory of this dissertation,the numerical simulation for the collision process is divided into various conditions,by using Ansys Ls-dyna for solution and Ls-prepost for postprocessing.It mainly studies the influence of different factors on impact force,including the initial velocity of the ship,the stiffness of the ship,the water level in the collision,the collision angle,etc.(4)Select three working conditions of high water level,straight bridge direction,horizontal bridge and normal water level and straight bridge,to analyze the influence of collision on the bearing capacity of bridge pier,and further to evaluate the bridge pier.(5)The fuzzy analytic hierarchy process has been applied to establish the damage assessment system of the bridge after collision.