Study On The Relationship Between Axle Box Vibration And Track Irregularity

Track irregularity is the main cause of wheel-rail vibration,which affects the safety of train operation and ride comfort.Track inspection car which needs high cost and cannot be accurately and timely reflect the state of track irregularities,by studying the track irregularity,the corresponding relationship between axle box vibration data using the easily measured acceleration of the vehicle axle box assess the state of the track irregularity,efficient and economic for the line maintenance to provide effective information,eliminate safety hidden danger is of great significance.Based on the axle box acceleration and track irregularities as the research object,analyses the axle box at different speed and acceleration variation law under the working condition of track irregularity and the axle box acceleration integral turbulence,the relationship between the displacement and orbit the axle box vibration response and the corresponding relationship between track irregularity,main work and conclusions are embodied in the following aspects:(1)According to the vehicle dynamics parameters of Beijing Metro Line 4,the vehicle dynamics simulation model is established in Simpack.The inverse Fourier transform method is used to simulate the five order spectrum of the US orbit as the excitation input of the real model of dynamics simulation.(2)By analyzing the simulation results under various working conditions,the overall amplitude of the axle box acceleration increases with the increase of the track excitation when the speed is constant;The overall amplitude of axle box acceleration increases with the increase of velocity when the orbit excitation is constant.By calculating the coherence between the axle box acceleration and the track excitation,the axle box vertical acceleration has a strong coherence with the track vertical excitation,and the axle box transverse acceleration is coherent with the track transverse excitation at low frequency.After extracting the characteristic values of axle box acceleration in time and frequency domain,it is found that part of the characteristic values of axle box acceleration in time and frequency domain change linearly with speed under different track irregularity multiples.By using the time-frequency domain eigenvalues of axle box acceleration,a mathematical model for estimating the track irregularity state based on axle box acceleration and velocity is obtained.(3)The axle-box displacement was obtained by eliminating the trend term in the integration of axle box acceleration with polynomial fitting method.The amplitudefrequency distributions of axle box displacement and track excitation were obtained based on rain flow counting method,and the distribution curves were fitted.By comparing the displacement of axle box and orbital turbulence of amplitude-frequency distribution curves of different working conditions of track irregularity amplitude-frequency distribution fitting curve parameter ratio and amplitude are obtained by numerical integral axle box acceleration-frequency distribution relationship between the ratio of the fitted curve parameters,therefore the relationship between the axle box acceleration integral representation can be used the relationship between the track irregularity,Thus,the displacement response obtained by integrating axle box acceleration can be used to characterize the relationship between track irregularities.(4)Finally,the experiment of Beijing Metro Line 4 was carried out to obtain the acceleration and speed data of the actual vehicles in operation.Based on the analysis and calculation of the measured acceleration signal of the line,the variation rule of the measured axle box vibration information of Beijing Metro Line 4 under different working conditions is obtained.The multiples of the rail excitation between stations obtained by integrating the measured axle box acceleration signals are in good agreement with the multiples of the orbit excitation derived from the characteristic values of axle box acceleration.The corresponding relationship model between axle box acceleration and track irregularity obtained in this paper can be used in actual line maintenance work and provide reference for daily maintenance of subway lines.69 figures,28 tables,68 reference.