Dynamic Stress Characteristics And Reliability Research For EMU Car Body And Equipment Cabin

The train as the main bearing part and the equipment cabin as the basis of the installment for other sub-equipment play a decisive role in the safety and comfort of the EMU.The Chinese standard EMU is a totally new symbolized product which owns an independent intellectual property right.It has profound meanings to analyze the dynamic stress characteristics and reliability of standard EMU car body and equipment cabin in the service process for the optimization of the standard design,decision of the reasonable maintenance period,the formulation of the design specification of the structural strength and the evaluation standard of the reliability test.The paper chooses the car body and equipment cabin of the standard EMU heading-train as the research object,with the reference to the data from long-term dynamic stress tracking test of the passenger dedicated line of Daxi,Zhengxu and Hada.The main research contents are as follows:1.Based on the finite element simulation and measured data,determined to characterize the body and equipment cabin stress characteristics of 21 stress measuring points are selected as the typical data,divided into 16 level stress spectrum and stress spectrum distribution fitting,the results show that the vehicle and equipment cabin stress spectrum obeys three parameter Weibull distribution.According to the Weibull distribution maximum stress value estimation,expand the compilation of measured data of stress spectrum.2.Based on the measured stress spectrum,using two different theory-Miner theory and Corten-Dolan linear cumulative nonlinear cumulative fatigue theory on vehicle and equipment cabin stress characterization of measuring points were evaluated,measured damage and fatigue life calculation results show that the key parts of the body and equipment cabin can meet the design life of 15 million kilometers,because the Corten-Dolan nonlinear cumulative fatigue theory considering the great influence of stress on the low stress amplitudes,the Miner linear cumulative theory is more conservative.3.According to a large number of measured data,dynamic analysis of the stress characteristics of different lines from the amplitude domain and frequency domain,The results show that the difference of line conditions has a significant effect on the stress characteristics of the car body and the equipment cabin.The effects of different speed levels on the car body and the equipment cabin are calculated.Under different speed levels,the equivalent stress of the car body and the equipment cabin increases with the increase of the speed.The equipment cabin is sensitive to the change of the speed,and the fatigue reliability of the equipment cabin should be paid more attention.4.The stress characteristics of different typical working conditions are analyzed.Thecurve condition has obvious influence on the stress characteristics of the measuring point,and the variation of stress level of the measuring point is different at different curve radius.The overload condition has little effect on the stress level of the measuring point.Due to air tightness load and aerodynamic effect,the stress level of the car body and equipment cabin increases sharply,and the amplitude of instantaneous stress changes obviously.