Dynamic Response Analysis Of Coupling Vibration Of Vehicle-Curved Bridges System

In recent years,China's road traffic has developed very rapidly.Curved beam bridges are widely used in highway construction.For example,in large approach bridges and large-span bridges,curved beam bridges are used inevitably.As the current drive density continues to increase,the speed and load of the vehicle continues to increase,making the vehicle more and more influential to the curved beam bridge.Compared with the ordinary bridge,the curved beam bridge is more complex in force and more prone to distortion and warpage.In engineering,a diaphragm is provided usually to reduce these deformations.Although many experts and scholars have studied the influence of diaphragms on curved beam bridges from the theory of static calculation,they have little research on the dynamic characteristics of diaphragms.Therefore,it is of great significance to carry out the study of the influence of the diaphragm on the coupled vibration of the curved beam bridge.In this thesis,the concrete curved box girder bridge is taken as the research object,and the theoretical analysis and numerical simulation of the coupled vibration of the axle are carried out for the curved beam bridge with and without the diaphragm.The main research results are as follows:1.According to Newton's second law,the dynamic differential equation of the 9-DOF three-dimensional three-axis vehicle model is established.Using the Newmark-? method,the MATLAB program is programmed to solve it.Based on the finite element theory,the 3D solid model of curved beam bridge is established by using COMSOL software.2.The COMSOL with MATLAB iterative program was written using the separation iteration method.The correctness and effectiveness of the method and program are verified by an example.3.The modal analysis of the curved beam bridge is carried out,and the influence of the diaphragm on the natural frequency is studied.The results show that the diaphragm can reduce the frequency of the vertical bending mode of the main beam,but the degree of reduction is small.4.The influence of the centrifugal torque caused by the up and down vibration of the vehicle body on the coupled vibration of the axle is studied.The results show that this factor has little effect on bridge vibration.Therefore,the vehicle vibration differential equation can be simplified accordingly.5.On the basis of considering the road roughness,the influence of the radius of curvature on the coupled vibration of the axle is analyzed.The results show that the lateral and torsional vibrations of the curved beam bridge increase with the decrease of the radius of curvature.6.The influence of the diaphragm on the coupled vibration of the curved beam bridge is studied.Firstly,the time-history curves of the various effect values(including deflection,rotation angle and stress)of the curved beam bridge with and without the diaphragm are calculated.Secondly,the bridge effect time history under the coupling of the vehicle and bridge is calculated.Curve;Finally,the simulation data is compared and analyzed according to the impact coefficient.The results show that the diaphragm has the ability to reduce displacement and stress of the curved beam bridge.