Rerformance Trends Assessment Of CRH2EMU Bogie Key Components

China’s EMU technology constantly innovates since the sixth railway speed increase. Now trains in major domestic railway have reached speed at over200km/h with the highest speed of380km/h, bringing China formally entered high speed rail era. However, with the continuous improvement of train speed, the loading conditions of structural components are becoming more and more severe, and the reliability requirements of key components of bogie are increasingly high. As key components of CRH2bogie, frame, axle box spring and positioning tumbler play vital roles for high speed trains running stability, ride comfort and ability to curve. Research on characteristics of dynamic stress or dynamic load, preparation of appropriate load spectrum and stress spectrum are important work for developing frame design standards, and also main foundation of the fatigue life and reliability analysis. The assessment and prediction of key components maximum load and stress, fatigue damage and reliability will improve the accuracy of EMU maintenance efficiency, reduce maintenance costs, provide scientific tools and service support for the safe and stable operation of EMU. In this thesis, strain gauge testing method is used to obtain stress time history of structural measuring point strain, and dynamometer spring and tumbler are used to continuously and directly test the axle box load and positioning tumbler load, then preparation of load spectrum and research on derived law are carried on, the distribution form of amplitude are analyzed and compared, and the fatigue damage and reliability are calculated and analyzed eventually. The main content of this paper is as following:1. Time domain and frequency domain characteristics of axle box spring and positioning tumbler load in typical conditions are studied.2. The derived law of dynamic load and stress with the effect of operating mileage and turning round is researched and the load spectrum is prepared.3. Distribution fitting type of load amplitude is compared, and the maximum load stress is calculated, and the spectrum is expanded.4. The influence of turning on points fatigue is analyzed and the fatigue value in different amplitude distribution is compared based Miner linear cumulative damage theory; the points reliability is analyzed based on stress-strength reliability model.