Research On Load And Dynamic Stress Of High-speed EMU Frame

In recent years,China's high-speed railway has achieved significant development.The high-speed railway has become an important tool for improving the living standards of the people,driving economic development along the railway,and a business card for China's foreign economic exchanges.As a major transport vehicle,the safety of the high-speed rail is of great significance.As one of the essential load-bearing components of high-speed trains,the bogie frame plays a vital role in the train-shaped device.Therefore,it is necessary to study the load conditions in actual operation,and its load-bearing characteristics will also provide essential references for the frame production,design,structural optimization,and prediction of service life.This paper takes a domestic high-speed EMU structure as the research object,based on the measured load and dynamic stress data of the Daxi test special line,combined with SIMPACK vehicle rigid-flexible coupling dynamic model and mode stress recovery method studies the frame load and stress characteristics from the two aspects of line measurement and theoretical calculation,and optimizes the frame load stress transfer coefficient.Mainly complete the following work:(1)The processing of load and stress data of the measured frame of the line was completed,and the variation characteristics of the 14 types of load systems in the time domain and frequency domain under different line conditions were analyzed.The Pearson correlation coefficient between the various load systems of the framework is calculated,and the correlation between the load systems in the time domain is analyzed.The method of compiling the measured load spectrum is studied,and the load spectrum of different speed grades,straight curve working conditions,and empty heavy vehicle working conditions are compiled.(2)The dynamic stress data of the frame was processed,the area division of the frame stress measurement points was completed,and the correlation between the frame load and the stress in the time domain was analyzed.Based on the load transfer coefficient of the indoor calibration test,the contribution ratio of each load system of the frame to the damage of the frame stress measurement point is calculated.The possible error of the load stress transfer coefficient is proposed,and the load transfer coefficient is optimized by the neural network algorithm.The optimization results are verified by the measured load and stress data.Using the measured load data and the optimized load stress transfer coefficient,the dynamic stress prediction of the line and other speed grades of the line is completed,and the effect of predicting the dynamic stress is verified.(3)Using the multi-body dynamics software SIMPACK,a rigid-body model of a high-speed EMU with a transmission system was established.The Wuguang orbital excitation spectrum is input,and the load data of the frame during operation on the line is simulated.At the same time,the dynamic stress of each node of the frame is calculated by the modal stress recovery method.The influence of speed grade and straight curve condition on the frame load is analyzed.The difference between the simulated dynamic stress and the measured dynamic stress of the line is compared.The dynamic stress of the frame is calculated by the optimized load stress transfer coefficient,and the difference between the dynamic stress and the simulated dynamic stress is compared.The effect of the optimized load stress transfer coefficient is verified.In this thesis,the frame load and dynamic stress are studied from the two aspects of actual test and theoretical simulation.The optimization of frame load stress transfer coefficient is proposed,which can provide reference for the application of frame load spectrum and dynamic stress acquisition method.125 figures,22 tables,76 reference.