Research On Track Disease Identification Based On Vehicle Response

High speed railway is the main artery of the country's economic and social development.It is also a beautiful business card for our country on the way of being powerful and prosperous.With the planning and implementation of the "eight vertical and eight horizontal" high-speed railway network,more and more high-speed trains and lines will be put into operation.The safety of trains and lines is becoming more and more concerned.Because of the high running speed,the interaction between the train and the track is remarkable.The change of the track state is affecting the train operation performance.Especially,when the track line has damage or failure,it is more likely to cause a great impact on the train traffic safety.Therefore,it is very important to detect the state of the track and further evaluate its influence on the vehicle performance.Limited to the dynamic analysis technology and the actual operating condition of the vehicle,the traditional researches have less attention to this issue.This paper studies the relationship between the track state and the vehicle performance response on the basis of the vehicle orbit coupling dynamics,and the main contents are as follows:First,the dynamic model of the vehicle track coupling is established.Compared with the traditional model and considering the convenience of the analysis.The dynamic model of the axle box system is added to identify the response relationship between the track state and the vehicle components.The calculated results of the new vehicle track coupling dynamic model are in good agreement with the actual test data,which verifies the accuracy and availability of the model.Secondly,a new accurate characterization model of rail damage is established,and a complete rail profile model is established for the irregularity of weld bead,rail scratch and rail stripping,which solves the problem of lacking diversity in the traditional simulation of track defect.At the same time,the corresponding physical model and the pertinent algorithm are adopted for the track irregularity of different wavelengths,so that the simulation model can effectively and truly reflect the actual state of the track profile change after the rail damage.Considering the efficiency and limitation of the simulation model of the vehicle track coupling dynamic in the long track simulation,the numerical algorithm of the vehicle track coupling simulation model is analyzed,and the influence of the track length on the calculation effect is analyzed.In view of the key problem that the computation cost significantly increases with the increase of the track length,an approach called sliding window method for calculating the track and vehicle coupling,which is suitable for the long line,is proposed.The accuracy of the sliding window method is verified by the analytic solutions of the vibration response of the simple supported beam and the results of the finite element calculation.At the same time,compared with the direct calculation method of the traditional vehicle track coupling simulation model,it is proved that the sliding window method can still have high calculation efficiency on the premise of considering the complete track structure and the change of the structure under the rail.It is especially suitable for the simulation of dynamic coupling between the vehicle and the long track.Finally,based on the propose simulation model and algorithm,the relationship between rail damage and vehicle response is systematically studied and analyzed.In the time domain,the characteristic parameters of vehicle response caused by different wavelengths are studied,in which case the vehicle response wave and kurtosis factor caused by the long and short wave irregularity excitation can be distinguished well.In addition,the corresponding relationship between the vehicle response and the approximate wavelength rail damage is identified.By calculating the wavelet energy spectrum of the response of the vehicle caused by the similar track damage,the law of the response change of the vehicle under the excitation of different damage model within similar short wave irregularity is revealed.In frequency domain,the main frequency characteristics of vehicle response caused by track defects with different wavelengths are studied,and the corresponding track damage forms can be identified by vehicle response directly.At the same time,the disturbance in the frequency domain of vehicle response caused by random irregularity is discussed.Considering the special conditions such as settlement,because the vehicle response excited by the long wave track irregularity cannot be directly detected by the wavelet transform,identifying the long wave track irregularity directly by the response of the car body is analyzed,and the fractal method is used to quantify the vehicle response caused by long wave irregularity such as settlement,which is beneficial to the numerical identification and quantitative assessment of the specific state of the track..