| Due to the widening of urban transportation range and the construction of urban rail transit,modern rail transit has become an indispensable part of the city,of which the subway has more small radius curves,lighter axle weight,more frequent rail vehicle braking and starting,so it is more likely to produce rail rail wave wear disease,which will not only affect the normal wheel-rail action relationship during the train operation,resulting in the vehicle and rail structure to occur Fierce vibration,reduce the comfort of train operation,to the subway vehicle operation caused by security risks,and the detection and diagnosis method is costly and efficiency to be improved.Therefore,in today’s rapid development of modern rail transportation,there is an urgent need to carry out research on the influence of subway rail wave wear on wheel-rail dynamic response under variable speed conditions and effective detection and diagnosis to provide reference and basis for improving train operation safety and reducing operation and maintenance costs.In this paper,the vehicle-rail dynamic model is established according to the parameters of actual subway vehicles.By establishing the rail corrugation numerical model method,the wheel-rail dynamic characteristics in the rail corrugation zone of subway are calculated,analyzed and studied.Two rail corrugation detection methods based on axle box acceleration vehicle dynamic response signal are proposed for the diagnosis and identification of corrugation under variable speed conditions.The simulation signal is used to verify the validity of the algorithm in practical engineering.The following are the main research contents and achievements of this paper:(1)By using the multi-body dynamics simulation software SIMPACK and referring to the actual parameters of a domestic metro train,the dynamic analysis model of Metro vehicle-track is built,and the German spectrum is selected as the excitation of track irregularity and the straight and curve lines are set.At the same time,the characteristics and causes of common rail wave wear damage are analyzed,and the rail wave wear damage simulation model is established by using Matlab software.(2)For the problem of rail wave wear under variable speed conditions,set different traction and braking conditions,change the depth and length range of rail wave wear damage as well as vehicle variable speed interval,simulate and analyze the dynamic characteristics of vehicle operation on straight line and curved line with radius of 300 m respectively,and evaluate the wheel-rail condition with wheel-rail vertical force,wheelset lateral force,derailment coefficient and wheel unloading rate as evaluation indexes,and get the influence of rail wave wear damage on dynamic characteristics of subway vehicles.(3)For the variable speed condition rail wave mill excitation generated by non-smooth FM signal,proposed wavelet synchrosqueezing transform algorithm for its time-frequency analysis,to achieve the wave mill fault feature extraction and wave mill wavelength diagnosis,and the use of rail wave mill simulation signal and field measurement wave mill signal for analysis and verification.The method can effectively eliminate the interference signal caused by rail vibration,the traction and braking conditions of the rail wave mill fault signal,to achieve the fault frequency location and identification.(4)Taking Hermite function as window function,a new optimum reallocation coordinate is put forward so that its frequency energy gathers on the instantaneous frequency of the transient signal.The optimized redistribution multi-window spectrogram algorithm is applied to the fault diagnosis of rail corrugation under variable speed conditions,and is analyzed and verified with simulation signal and measured signal.Compared with other methods,this method can accurately analyze the fault frequency and get more accurate results in the field measured data,which reflects its high resolution,high time-frequency aggregation and strong anti-interference ability. |
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