Study On Loads Frequency And Loads Spectrum Characteristics Of High-Speed Vehicle

In recent years, high-speed railway in China has been developing rapidly, and the continuous improvement of the speed of the vehicle makes the problem of the bogie loads characteristics getting more and more attention. Bogie loads have decisive impacts on bogie vibration characteristics and structural strength. High-frequency vibration not only affects the safety and comfort level of vehicle operation, but also accelerates the fatigue damage of the vehicle system components. A study on the loads frequency transmission principle and loads characteristics on the high-speed vehicle bogie has been carried out; using numerical simulation analysis method combines the analysis on the measured data of bogie loads. The works have been done in the thesis are as follows.The study background and significance of the thesis have been introduced, the study status domestic and overseas has been summarized, the study objectives and the study methods of the thesis have been cleared. The finite model of the bogie frame and wheel-set have been established, whose vibration characteristics have been analyzed by Block Lanezos principle to get their natural frequency and model shape.The vehicle system dynamics model has been established by SIMPACK, imposing the measured line track spectrum to calculate the wheel-rail excitation forces and bogie loads. The wheel-rail excitation forces are used in transient dynamics analysis of the bogie in ANSYS to calculate bogie loads, stress of the bogie frame and wheel-set. The transmission principle of the frequency of the bogie loads has been studied by comparing and analyzing the calculated results of ANSYS and SIMPACK.The affective cut-off frequency for data processing has been obtained by analyzing the bogie loads characteristics and loads transmission principle extracted from numerical simulation calculation. The measured data of the bogie loads have been processed to make the load spectrum of the bogie. The data of the bogie loads when the vehicle is running out of the garage, on the straight line, curve in high speed have been sampled to get the axle spring loads and positioning tumbler loads, whose characteristics have been analyzed respectively both in time domain and frequency domain.Conclusions got in the thesis are as follows, the results of ANSYS transient dynamics analysis show that elastic resonance may occur on the bogie frame. There are significantly attenuations on frequency components of bogie loads in the transmission process from first suspension system to bogie frame and second suspension system. Relevancy between frequencies of the bogie frame stress and wheel-set stress has been discovered.Bogie loads of the vehicle running on the high speed straight line condition show characteristics with small amplitude and high frequency. While the vehicle is running in or out the garage, passing turnout and small radius curves, the characteristics of the bogie loads are large amplitude and low frequency. In general, the amplitude of the dynamic bogie loads is small.