Numerical Simulation Of Vehicle Collision And Protection Technology Of Pier

With the rapid development of urban transportation industry and the soaring number of cars and urban bridges,accidents of vehicle hitting bridge are frequently caused.Collisions between vehicle and pier are not only a serious traffic accident,but also a damage to urban bridges,resulting in economic losses and threating to human life.Even in Europe and America with developed traffic management,such accidents cannot be avoided.The research on protection of bridge in collision is initially about with ships impacting across waterway bridges in China.Although the mass of the vehicle is far less than that of the ship in collision,the speed of vehicle is much higher than ship's and the impact position is relatively concentrated,so the local damage of bridge is probably more serious.At present,the research on collision between vehicle and pier is still at the initial stage and the codes and regulations are still not standard in our country,so we need to arouse our attention and reflection.In the design and management of protection of urban bridges in collision,we need to form a complete studying system.In this paper,the finite element analysis software LS-DYNA is used to numerical simulate the process of vehicle impacting on pier.The paper's main research contents and achievements are as follows:(1)The serious accidents of bridges subjected to collision of vehicles,and the related research codes and regulations in China and abroad are summarized,the calculation method of numerical simulation and theory of contact algorithm is expounded,and the material constitutive model of concrete is compared.(2)A vehicle-pier collision model is established by numerical simulation,the vehicle impact force and energy conversion time history in different conditions are compared,the relationship between vehicle impact force about mass and speed is analyzed.At the same time simplified formulas of vehicle impact force are put forward.(3)The pier anti-collision facilities were introduced at present,the collisions between vehicle and anti-collision facilities are analyzed by numerical simulation,the design and optimization programs of anti-collision facilities are proposed.Polyurethane foam is the main energy absorber in anti-collision facilities in plan 1.The impact force reduction is more obvious at the speed of 80-120km/h,and the average impact force at all speeds is 38.2%.The FRP buffer ring is the main energy absorber in anti-collision facilities in plan 2.The impact force reduction effect of the anti-collision facility is obvious at the speed of 40-80km/h,and the average impact force at all speeds is 39.3%.The two projects' result show that both of them have good effect on collision protection.Its protective functions of the vehicles and piers are proved,and it provides a theoretical basis for anti-collision facilities in engineering applications.