Research On Long Wavelength Track Irregularity Management Of High Speed Railways

Track irregularity,as an incentive for wheel-rail contact,directly affects the ride index.Therefore,the implementation of scientific monitoring and management of the entire process of the occurrence,development and deterioration of track irregularity is the key to ensuring ride comfort,ride index and safety.Wavelength and amplitude of track irregularity are two important parameters in track management.The track irregularities are random irregularities and contain many different wavelength components with a wide range,and their effects to the vehicle are also different.With the increase of train speed,the shaking problem caused by long-wavelength irregularities becomes more and more significant,and the wavelength range that needs to be controlled is also getting longer.The current status of domestic and foreign track long-wavelength irregularity detection,management standards and methods are systematically summarized,and the shortcomings in this field in China are analyzed.Using theoretical simulation and mathematical statistics and other analysis methods,combined with comprehensive detection of actual measured data,the sensitive wavelength of the main EMU is studied,and the correlation between the long-wavelength irregularity of the track and the dynamic response of the vehicle is studied,the long-wavelength irregularity dynamic and static control standards and evaluation methods are proposed.By optimizing the sensors and long-wavelength signal processing,irregularity detection of longer wavelengths is realized.The main work of this article is as follows:(1)The characteristics of irregularities are studied,and a vehicle-track-foundation coupling dynamic model and a space state model based on system identification theory that can be used for correlation analysis of track irregularities and vehicle responses are established.Based on the coupled dynamics theories of the vehicle-track system,establish a high-speed vehicle-track-foundation coupling dynamic analysis model,which can be used to calculate and analyze the vertical vibration characteristics under different irregularity disturbances.A state-space model based on the system identification theory is established,including algorithms,transfer functions,ordering criteria,and model verification methods.The measured data are used to estimate the transfer function between the long-wavelength irregularity and vehicle lateral acceleration correlation model.The correlation between the long-wavelength irregularity and the lateral acceleration of the vehicle are analyzed.Through the combination of the vehicle-track-foundation coupling dynamics model and the spatial state model based on system identification theory,theoretical support for the systematic analysis of the effects of track irregularity on vehicle vibration is provided.(2)Based on the analysis of a large number of measured data,combined with theoretical simulation calculations,the sensitive wavelengths of the main EMU are determined and the management wavelengths of the long-wavelength irregularity at different speeds are proposed.The measured data of 5 different inspection vehicles under high-speed conditions and the theoretical simulation analysis of the main EMU at a maximum speed of500km/h are analyzed.It is concluded that there is a good correlation between the irregular sensitivity wavelength and the vehicle vibration frequency.Through reasonable deduction and comparison,the sensitive wavelengths of different vehicle models are obtained.The management wavelengths of long-wavelength irregularities at different speeds are proposed.(3)Based on coupling dynamic model and a space state model,the relationship between vehicle dynamic response and track irregularity amplitude at different speeds under the sensitive wavelengths is obtained.Based on theoretical simulation analysis and a space state model,the correlations between different amplitudes of track irregularity and vehicle dynamic response at sensitive wavelengths and different speed conditions are obtained.By analyzing the characteristics of actual irregularities which are roughly harmonic-shaped,using cosine irregularities as irregularity excitations,and changing the amplitude of track irregularities,the conclusions are as follows.Under the profile irregularity excitations,the wheel load reduction and the carbody vertical acceleration increase with the amplitude,and the change is basically in a linear trend.Under the alignment irregularity excitations,the indices of derailment coefficient and the carbody lateral acceleration increase with the amplitude,and the change is basically in a linear trend.Based on the State Space Model(SSM),the carbody lateral acceleration which inverted by carbody lateral sensitive wavelength and transfer function increase with the amplitude,and the change is basically in a linear trend.Compared with the dynamic result,the amplitude is smaller.(4)The dynamic management standards and evaluation methods of track long-wavelength irregularities are proposed.Through the analysis of the measured dynamic data of high-speed railways,it is shown that the irregularity wavelengths below 70 m have a small impact on the evaluation of long-wavelength irregularities.The change of line shape is mainly concentrated in the 70-150 m bandpass filtering range.Based on this situation,the70-150 m bandpass filtering method for evaluating long-wavelength irregularities is proposed,which is more suitable for field data analysis and maintenance.Based on the correlation between the obtained vehicle dynamic response and the track irregularity amplitude,and comprehensively considering the train safety and comfort control standards,a recommended value for the dynamic management standard of 70-150 m bandpass long-wavelength irregularity was proposed(250～350km/h).(5)The static management standards and evaluation methods for long-wavelength irregularities are proposed.Based on the research and comparison of static detection and evaluation methods and chord length settings,through simulation and vehicle spectrum analysis,combined with the effective measurement ranges of different chord lengths of the midpoint chord measurement method,a long-wavelength irregularity based on the 60 m midpoint chord measurement method is proposed,which can meet the static long-wavelength irregularity control in the field.Through the comprehensive analysis of simulation and measured data,the recommended value of the long-wavelength irregularity static management standard for the 60 m midpoint chord measurement method is proposed(250～350km/h).Static long-wavelength irregularities are controlled in accordance with three levels of regular maintenance,planned maintenance and temporary repair.(6)The long-wavelength irregularity detection technology is optimized.Based on the laser camera technology and inertial reference method theory,the long-wavelength irregularity detection technology is optimized.A new digital inertial component has been designed,the previous installation mode of the vehicle body,frame,detection beam and other different positions has been changed,improving the integration and accuracy.A new long-wavelength signal filter is designed.By comparing and experimenting with the characteristics of different window functions and different system structures,a triangular-window and rectangular-window parallel-connected filter was finally adopted to achieve the optimized FIR filter under the minimum error criterion.It meets the profile and alignment long-wavelength irregularity test requirements of 150 m.