Finite Element Simulationn And Experimental Study On The Coupled Vibration Of Cable-stayed Bridge

Cable-stayed bridge has become one of the main bridge types for long-span bridges due to its beautiful shape,strong spanning ability,flexible arrangement of span,convenient construction and so on.With the construction of more and more span cable-stayed bridge,the coupling vibration problem of cable-stayed bridge is getting more and more attention.The vibration of the main beam and tower of the cable-stayed bridge caused by the earthquake action,the load of the car and the impact of the waves on the cable-stayed bridge may cause the large vibration of the cable in some cases.Due to the coupling of the cable and the bridge,the vibration of the cable will also cause a significant vibration of the bridge.The coupling vibration of the cable-stayed bridge can cause fatigue damage to the root of cable,such as the fatigue cracking and breaking of the cable,which affects the stress condition and normal operation of the cable-stayed bridge.Many related scholars have paid more and more attention to the coupling vibration of cable-stayed bridge and studied it,mainly considering the nonlinear vibration of the nonlinear vibration cable-stayed bridge.The theoretical analysis model of the cable-stayed bridge is the combination of single cable and cantilever beam,the cantilever beam end is fixed and the end is connected with the cable.In this paper,a complete bridge model with six cable-stayed cables is established to preliminarily observe the coupling vibration of cable-stayed bridge.The main contents and research results are as follows:1?In this paper,two models of the finite element OECS and MECS of the cable-stayed bridge are established.Through the comparison and analysis of the modal vibration modes of the two models,the first order vibration of the tower,the two order vibration of the beam,the first vibration of the cable are coupled,and the corresponding vibration frequency ratio of the three is 1:1.11:1.21.It can be seen from the vibration pattern that second order vibration of beam and the first-order vibration of tower can cause the vibration of the beam,cable and tower of the cable-stayed bridge belongs to the global vibration,the first-order vibration of cable failed to cause the vibration of the beam and the tower belongs to the local vibration of cable-stayed bridge.2?The vibration analysis of the finite element MECS model is mainly based on the free vibration and forced vibration of the whole bridge.In the free vibration,the components of the cable-stayed bridge are resonant at the first order vibration frequency and the first order vibration frequency of the tower.In the forced vibration,the first order vibration of the cable is obvious when the first order vibration frequency of S1 is used as the excitation frequency,and the vibration of the cable-stayed bridge is local vibration.The vibration of the beam,cable and tower of the cable-stayed bridge can be vibrated with the two order vibration frequency of the beam and the first vibration frequency of the tower as the excitation frequency,and the vibration of the cable-stayed bridge is global vibration.The coupling degree of each component in global vibration is greater than that of local vibration.3?By comparing the experimental results with the simulation results of the finite element model,it can be found that the local and global vibrations of the cable-stayed bridge are produced by the external load of the related frequency.The model test verifies the correctness of the finite element analysis,and provides the technical support for the further study of the coupling vibration of the cable-stayed bridge by using the finite element model.