| Nowadays,as the number of highway bridges and multi-purpose bridges increases year by year,researchers pay more attention to the dynamic interaction between vehicles and bridges.The bridge surface roughness is one of the main factors affecting the coupled vibration response of vehicle-bridge.The irregularity value of different grades of bridge deck will cause different degrees of vehicle vibration and reflect the flatness of the pavement profile section curve.Therefore,the accurate bridge deck irregularity simulation method is the premise of the vehicle-bridge coupling numerical simulation.In the study of dynamic response of highway bridges,it is generally treated as a sinusoid.Therefore,how to choose the appropriate bridge surface irregularity simulation method is a key issue in the numerical simulation of vehicle-bridge coupling.In this paper,the bridge surface irregularity is regarded as a random function which accords with Gauss stochastic process with zero mean value and various states.It is based on harmonic superposition method,white noise filtering method,AR model method and inverse fast Fourier transform method,using MATLAB to write the corresponding simulation program of the road surface irregularity simulation method,using the national standard GB/T7031-86 specification data to simulate the A,B,C grade road surface has obtained good results,and its advantages and disadvantages be explained.At the same time,in order to study the practicability of different bridge deck irregularities simulation method in vehicle-bridge coupling,a simple supported hollow slab girder bridge,a variable-section box girder bridge and a T-beam bridge are taken as examples to establish a three-dimensional model of the bridge by Ansys.The vehicle’s three-dimensional model is established by using the parameters of the actual vehicle.The vehicle-bridge coupling solve program based on the Newmark-β integration method is programmed by Matlab.The maximum dynamic displacement response of vehicles passing through grade B pavement at 20 m/s speed under different bridges and working conditions is analyzed,the measured and simulated deck irregularities of Le’an River Bridge in Qiaomuwan are compared and analyzed.Based on the comparison of simulation time-consuming,bridge vibration response results and measured data with simulation results,four common bridge surface irregularity simulation methods are evaluated.The results show that the spatial spacing of the harmonic superposition method cannot be too small.The error of the noise filtering method is relatively large,and the overall calculation of the AR model method is cumbersome.The fast Fourier transform method has no overall fluctuation and thesimulation speed and accuracy can meet the simulation requirements.For comprehensive consideration,it is recommended to use the inverse fast Fourier transform method to simulate bridge roughness. |
