Study On Damage Identification Of Ballastless Track Based On Dynamic Response Analysis Of Vehicle

The ballastless track of high speed railway is inevitably damaged during the long term service.To ensure the safe and stable operation of the railway line,how to identify and evaluate the health status of the track becomes the key.The research on the damage identification of the ballastless track based on the vehicle dynamic response is an important part of the research on the damage identification technology of ballastless.Based on the simulation data,the paper proposes a set of ballastless track damage identification method based on analysis of vehicle dynamic response,the main research work include the following aspects:(1)The current methods and items for the detection of vehicle dynamic response data are summarized.In combination with the time-frequency characteristics of the dynamic response data of various parts of the vehicle before and after the damage of the simulation model,the vertical acceleration data of the axle box and bogie is selected Damage identification basic data.(2)The current status of the development of structural damage identification technology is summarized and studied.Combining with the characteristics and damage forms of ballastless track structure and the signal characteristics of vehicle dynamic response,the selected variational mode decomposition method is used to analyze the dynamic response data of the vehicle and optimize the relevant parameters.The applicability of the method of signal decomposition in mechanical fault diagnosis to the identification of ballastless track based on vehicle dynamic response is verified.(3)Based on the variational modal decomposition results of the vertical acceleration data of the axlebox and bogie,the characteristics of the vehicle's dynamic response ballastless damage fault function are determined according to the changes of characteristics of the signals of the track in the time domain,frequency domain before and after the ballastless damage.Based on Hilbert spectrum and energy spectrum,the applicability of the fault function to the common damage of the track is analyzed.(4)From the aspects of anti-excitation of track irregularity ability,damage sensitivity,and damage discrimination ability,the preselected damage indices in the time domain,frequency domain and time-frequency domain are optimized.And by means of principal component analysis method,the selected indicators are f and the track damage identification index is established to characterize the changes of time and frequency characteristics of the track damage-induced vehicle response to track damage characteristics.(5)The position,degree and type of ballastless damage condition under the ballastless track slab and the support layer were identified by a combination of the sliding detection technology and the support vector machine pattern recognition.It is concluded that the method can complete the damage location and degree identification,but can not identify the small damage and damage types.