Study Of The Fatigue Test Load Conditions Of CRH380BL Bogie Frame

It’s very important to take into account the problem for the fatigue strength of the key components on railway vehicle during the development of the railway industry, especially for studying the fatigue strength of bogie frame. Based on "CRH380BL EMU long-term tracking test" project took by Structural Strength Testing Laboratory in Beijing Jiaotong University, considering CRH380BL-6202 of Jinghu line and CRH380BL-6453 of Jingguang line and CRH380BL-6246 of Hada line as experimental vehicle with EMU bogie frame for the experimental object, this paper research the dynamic stress changing of frame works at different loading conditions and calculates load value. Also this paper ensures that the results of fatigue experiment could be equivalent to the results of the line experiment. The main research work and conclusions of this paper are as follows:(1) According to studying and analyzing the calibration experiment on the specific EMU bogie frame, it proved that both load and strain have a linear relationship on the test;(2) According to dealing with the tracing experiment test data for a long time, it proved that the stress spectrum at test point follows Weibull distribution. Also it’s inferred that the case for comparing the maximum stress estimated value to real-test data is in accordance with real-line state;(3) Based on studying dynamic stress characteristic and the fatigue damage of bogie frame at different loading conditions, calculating the damage value at test points could get that the frame can meet the operating requirement of EMU 12 million kilometers. Comparing equivalent stress of frame test points on three lines, line conditions have a larger influence in frame. According to analyzing the dynamic stress of frame at different speed, the dynamic stress fluctuation range at the acceleration and deceleration conditions is greater than at constant speed;(4) According to processing results of the calibration and track experimental data, setting up proper mathematical model, the equivalent stress would be got by inverse operation. Finally, the equivalent stress calculated and the equivalent stress tested really had been compared and analyzed. Result shows:Calculated equivalent stress can mainly stand for measured equivalent stress, so the load value calculated by this paper can meet the requirements of testbed.By studying in this paper, the fatigue design specifications, which could be adapted to our high-speed railway line in reality, had been established. It’s very important to ensure the safe of high-speed trains and reliable operation, and complete the relative design standard. Ultimately, it could provide theoretical foundation and useful reference in the type EMU experiment in future.