Research On The Detection Method Of Rail Corrugation Based On Response About Interior Noise Of Metro And Vibration Acceleration Of Axle Box

In recent years,Urban rail transit of China has been developed vigorously,subways had been built in many cities,and it has become an indispensable part of people’s daily travel.But with this comes the increasingly heavy subway inspection and maintenance operations,rail corrugation is one of the rail defects in the detection operation.Different from high-speed railways,subway lines mainly appear in the shortwave corrugation of steel rails,which will directly affect the service life of subway trains,and will also cause problems such as excessive noise in the metro and abnormal shaking of vehicles,greatly reducing the comfort experience of passengers.Therefore,solving the rail corrugation has become an urgent problem to be solved at present.Starting from the noise in the metro and the vibration acceleration of the axle box of the vehicle in this thesis,a method to quickly identify the rail corrugation was proposed through a large number of measured data analysis.Firstly,the current development background of urban rail in China was described,and rail corrugation was stated from the characteristics of rail corrugation,formation mechanism,corrugation classification,hazards and other aspects.Based on the axle box acceleration integration method of inertial reference method,a rail dynamics model using SIMPACK was established for verification.In the model,parts such as wheels and axle boxes are treated as rigid bodies,and the measured data of CAT wave corrugator were imported into SIMPACK model,a virtual sensors are installed on the axle box,and the collected axle box vibration acceleration was band-pass filtered,and the vertical displacement was obtained by quadratic integral in MATLAB,and compared with the data measured in the field of CAT corrugator,then the applicable conditions of the inertial reference method and the influence of sampling frequency,vehicle speed,curve radius and other factors on the detection accuracy of rail corrugation are studied.Secondly,the discriminant index of rail corrugation based on rail corrugation index was proposed,including the discriminant index of axle box vibration acceleration and the discriminant index of interior noise.The design principle of the discriminant index is to screen out the abnormal parts of axle box vibration acceleration and interior noise exceeding the threshold by fitting the rms value of acceleration or the sound pressure level of interior noise to vehicle speed.And then,a comprehensive wave corrugation identification method based on interior noise and axle box vibration acceleration was designed.Finally,the acceleration signal was decomposed and denoised by using CEEMD decomposition method,and MATLAB quadratic integral was carried out to realize the inversion of rail corrugation.The effectiveness of the method was verified by comparison with the measured data.Based on the rail corrugation identification method proposed in this thesis,the rail corrugation can be quickly identified in the long-distance subway lines,manpower and material resources can be saved to a certain extent,rail corrugation testing operations can be simplified.It can provide reference for rail corrugation,rail corrugation testing and other work.