Vehicle Bridge Coupling Vibration Analysis Based On Non Inertial Reference System Under Strong Excitation

With the development of highway and railway construction,the progress of science and technology,the development and application of new materials,and the improvement of bridge construction technology,the bridge structure gradually develops to the direction of large-span and gentle,the driving speed and load of vehicles are also increasing relatively,these factors will cause the problem of dynamic interaction between vehicle and bridge structure to become more and more prominent,and the structural vibration response will be more complex.Moreover,with the increase of large-span important node bridges and the increase of traffic density,the probability of heavy-duty and high-speed vehicles(trains)driving on the bridge under the accidental strong excitation such as earthquake and strong wind increases greatly.At this time,the vehicle bridge coupling dynamic system will have spatial motion,and the large span bridge structure will produce instantaneous dynamic rigid body translation+rigid body rotation+elastic deformation relative to the earth.If the static boundary condition of the traditional inertial reference frame is still used to establish the vehicle bridge coupling dynamic model,it has certain limitations.In view of the unique spatial motion characteristics of long-span bridge structure under strong external excitation,this paper established a vehicle bridge coupling dynamic interaction model of three-dimensional Euler beam based on non inertial reference system,simplified the vehicle load into a 1/4 vehicle model,and based on the Hamilton variational principle and the vehicle dynamic equilibrium relationship,the general nonlinear dynamic control equation of vehicle bridge coupling system in space motion is established.Then,the equations are solved by the mode decomposition method,Galerkin integral and Runge Kutta method.The vibration response of simply supported beam bridge structure under the external accidental strong excitation in the condition of relative vertical,horizontal rotation and vertical translation is studied through the calculation examples,and the influence of bridge span,driving speed,vehicle stiffness,vehicle damping,deck irregularity and other parameters on the vibration response of vehicle bridge coupling system are discussed;at last,the coupling effects of vertical translation and horizontal rotation,vertical rotation and horizontal translation are analyzed,it is found that the coupling effects of vertical translation and horizontal rotation have significant effects on the vertical vibration of vehicle bridge system.