The Parametric Study On The Source Of Metro Train-induced Vibration Based On Different Train System States

The rail transit construction in China is developing rapidly.However,the vibration problem of the rail transit is becoming increasing obvious,which has attracted extensive attention.The existing research results and test data elucidate that the train-induced vibration response data measured at a certain mileage and within one day varies with different pass-by trains.This phenomenon shows that the difference in train system states can affect the environmental vibration response.At the same time,the existing criteria for the metro vibration source also indicates the significance of considering the difference of train system states for correction,including wheel-rail roughness states,axle load,wheelset mass vehicle parameters,etc.But the specific impact of different train system states on the vibration of environmental vibration is not yet clear.Therefore,it is necessary to investigate the influence of train system states on the train-induced vibration.With the support of the National Natural Science Foundation of China named “Study on the parameter uncertainty of metro train-induced environmental vibrations based on hybrid prediction method”(No.51978043)and “Study of Prediction Accuracy and Reliability of Train-induced Vibration and Its Environmental Influence”(No.51778049),in the present study a train-track-tunnel-soil layer rigid-flexible coupling numerical model was established.In addition,the in-situ wheel roughness measurement in a metro line was carried out using the contact wheel out-of-round instrument Tri Tops.The main works are as follows:1.The Tri Tops contact out-of-round wheels instrument was used to test 48 wheels of a metro train in a metro line.The degree of development of out-of-round wheels caused by the increase in operating hours and mileage of metro trains was analysed.And the main wavelength and order of the out-of-round wheel were analyzed.Additionally,the relationship between the out-of-round wheel and train-induced vibration was discussed.2.A three-dimensional vehicle-track rigid-flexible coupling numerical model was established by using the multi-body dynamics software SIMPACK and finite element numerical simulation software ABAQUS.At the same time,it was coupled with the three-dimensional finite element tunnel-soil layer numerical model with infinite element boundaries.The model can simulate the vibration source of the train-induced vibration with high accuracy and high calculation efficiency.The model could also simulate the impact of wheel roughness on train-induced vibration with high accuracy.The measurement data can be used to verify the numerical model.3.With the established train-track-tunnel-soil layer rigid-flexible coupling simulation model,the effects of train load,suspension parameters,wheelset mass,wheel out-of-roundness,and rail roughness on the vibration response of train-induced vibration are calculated.Analyze the influence of different types of train system states on the dynamic response of track structure and tunnel structure in different frequency bands.And the effect of different train system states on the maximum vibration level Z direction at the tunnel wall.The results show that when the train speed is 60km/h,the out-of-round wheel will affect the vibration response of the 40～80Hz frequency band and 12 d B vibration source.Vehicle load affects the dynamic response in the frequency band below 25 Hz.The greater the vehicle load,the greater the dynamic response.However,the changes of the first and second suspension stiffness have almost no effect on the dynamics of the track structure.