Research And Application Analysis Of Load Spectrum Of Subway Pantograph Contact Force

In recent years,urban rail transit has developed rapidly,and subway vehicles have been widely used.The pantograph is an important device for the current transmission of subway vehicles.With the opening of a large number of new subway lines,the structural fatigue damage problem of pantograph is also increasing.At present,the evaluation standard of pantograph fatigue strength is mainly focused on the pantograph of high-speed railway,and the research of the fatigue strength of subway pantograph also mainly uses standards of high-speed railway.In-depth studies on issues such as fatigue strength are necessary.Load spectrum is an important analysis method in pantograph structural strength and fatigue life analysis.This thesis will carry out research on the load spectrum and application of subway pantograph contact force.Its research content mainly includes the following aspects:the correlation coefficient method combined with the EEMD(Cluster Empirical Mode Decomposition)method is used to filter the eigenmode function IMFs of the sensor data,First,based on the data of a subway test line in China,a dynamic load preprocessing method was studied.In this thesis,the correlation coefficient method combined with the EEMD method is used to filter the IMFs of sensor data,so that the trend of the signal data can be analyzed and removed.All the processed sensor data are calculated to obtain the contact force.And the abnormal value of the contact force is identified,eliminated and interpolated to obtain a more reasonable contact force.And the method is verified by an example analysis.Secondly,based on the pre-processed contact force,this thesis studies the theory of contact force load spectrum.Data compression was performed on the pre-processed contact force load,and the average and amplitude of the load were counted by the four peak valley rain-flow counting method.Make assumptions about the distribution rule satisfied by the statistical data of average and amplitude,and focus on the parameter estimation of the Weibull distribution of amplitude through the method of combining the correlation coefficient method and the maximum likelihood method.The rationality of the parameters and the correctness of the distribution hypothesis are tested by the kernel density estimation method and K-S test.The joint probability density distribution function of average and amplitude is established to solve the extreme value of the contact force load spectrum,and further study on working out the load spectrum.Then,based on the research of the pretreatment method of contact force and the method of working out the load spectrum,this thesis studies the load law and load spectrum of the subway pantograph.This thesis analyzes the load characteristics of subway pantograph under different speed levels,opening and closing conditions,and mainly studies the time domain characteristics,statistical characteristics,and frequency domain characteristics of the load.At the same time,this thesis identifies and studies the impact load.And this thesis also studies the characteristics of the distribution parameters of load distribution law,the characteristics of extreme load and contact force load spectrum under different working conditions.Finally,based on the study of load law and load spectrum of contact force,this thesiscarries out relevant application analysis.Based on the load law and load spectrum,combinedwith the finite element method,this thesis studies the external load application method ofpantograph strength test analysis,and also gives the recommended test methods for strengthanalysis.According to the load-stress transfer relationship,combined with the extrapolatedS-N curve and fatigue damage theory,this thesis predicts and analyzes the fatigue life of thedangerous points of the pantograph components.