Nonlinearity Dynamic Analysis Of Vehicle-Bridge Coupling System With Considering External Excitation

Traffic load,as one of the main live loads passing through bridges,has an important impact on the safety of bridge structures.With the development of modern science and technology,the development and application of new materials(such as new high strength steel,advanced composite materials)and the improvement of bridge construction technology,the bridge structure gradually develops towards the direction of large-span,new-type and light-weight.With the increase of traffic volume,the increase of vehicle speed and the relative increase of load,the stability and safety performance of bridge structure will be improved accordingly.As a result,more and more attention has been paid to vehicle-bridge coupling vibration.At present,scholars in the field of vehicle-bridge coupling have studied the process of vehicle-bridge coupling from only exploring the coupling between vehicle and bridge itself(without considering external excitation)to considering the influence of external excitation(wind load,earthquake,etc.)on Vehicle-bridge coupling.However,in the current study,considering the external excitation,the study of vehicle-bridge coupling nonlinearity is more based on the non-linearity of vehicle-bridge contact force and the non-linearity between wheel and rail,but less on the non-linearity of bridge structure itself.In practice,many bridge structures work with cracks,but most of them do not consider the influence of external excitation in vehicle-bridge coupling analysis of cracked beams.On this basis,the influence of the non-linearity of the bridge structure and the surface crack of the beam on the vehicle-bridge coupling vibration is studied under the external excitation.Firstly,the research background,research status and research significance of vehicle-bridge coupling vibration system with external excitation are introduced in detail.Then the Euler-Bernoulli beam is used to study the simply supported beam under seismic excitation.Considering the geometrical nonlinearity of the beam,the nonlinear dynamic governing equation of the vehicle-bridge coupling system under seismic excitation is established based on Hamilton's principle.The Runge-kutta method is used to solve the nonlinear governing equation,and the seismic excitation effect,driving speed and driving speed are studied.The dynamic response of vehicle-bridge coupling power system to vehicle mass and other parameters.Secondly,by introducing the vehicle-bridge coupling dynamic model with cracked beams and taking the irregularity of bridge deck as the input of external random excitation,the vehicle-bridge coupling dynamic equation with cracked beams under the irregularity of bridge deck is established by Hamilton principle and solved numerically by Runge-Kutta method.The parameters are analyzed by Matable.Under the same grade of bridge deck irregularity,the influence of crack depth,vehicle speed and mass ratio of bridge to vehicle on bridge structure displacement is studied.Finally,this paper summarizes the research work and puts forward the prospects for the research direction of vehicle-bridge coupling vibration.