Statistical Analysis Of High-speed Axle Load Spectrum And Reconstruction Of Load Spectrum Of Experiment Bench

With the “one belt,one road” strategy putting forward,the railway industry has been developing vigorously.As the carrier of railway passenger transport,high-speed EMU plays an important role in railway transportation.As the key part of the running part of high-speed EMU,the requirement for wheels and axles of high-speed and heavy load is increasing.Therefore,based on the measured data,the whole life load spectrum is obtained by extrapolation,and the load spectrum of experiment bench which is convenient for the experimental personnel to load is compiled,which is very important for the analysis of the structural strength and fatigue life of the axle,and has far-reaching research significance and engineering application value.In this paper,with the help of data processing software n Code and MATLAB,the dynamic stress signal of the wheel and axle on the actual operation line of CRH2 A EMU is processed and analyzed.The specific research contents are as follows:(1)The calibration test data of the force measuring wheel set on the experiment bench are analyzed and processed,and the vertical load stress transfer coefficient and the lateral load stress transfer coefficient of the axle are obtained.The finite element model of the axle is established,and the loading analysis under three working conditions is carried out according to UIC510-5 standard.Thus,the position of the key section on the axle is identified.(2)Based on the analysis of the measured data of the EMU wheel and axle,combined with the gyroscope signal to distinguish the working conditions,the corresponding stress spectrum and load spectrum are compiled according to the different working conditions.And the stress spectrum of the key section of the axle is compiled according to the finite element simulation results.(3)Select the appropriate data as the extrapolation sample,and use the time-domain extrapolation method based on peak-over-threshold model(POT model)to explore the extrapolation.In this paper,the best threshold selection method based on the multi-criteria decision-making idea is proposed,and the extrapolation results obtained by using the maximum likelihood estimation method and the probability weighted moment method to estimate the parameters of the generalized Pareto distribution are compared from three aspects of probability density analysis,damage value analysis and extreme value analysis.At the same time,the influence of different extrapolation multiples on the extrapolation results is analyzed.Finally,the parameters of generalized Pareto distribution are estimated by the maximum likelihood estimation method,and the load spectrum of the whole life is obtained by extrapolating the measured data.(4)According to the S-N curve and Miner’s linear cumulative damage theory,the damages of the full lifetime load spectrum are calculated after extrapolation.Using the method of equal damage,a 4-level program load spectrum suitable for loading on the experimental platform and convenient for the operation of the experimental personnel is compiled.On this basis,the influence of the loading sequence of spectral blocks is preliminarily explored.This result has certain practical application value.Through the above analysis,the statistical extrapolation of the load spectrum of the EMU wheel and axle and the compilation of the load spectrum of experiment bench are completed,which has certain reference value for the subsequent analysis of the structural strength and fatigue life of the wheel and axle.There are 61 pictures,33 tables and 44 references.