Study On Vibration Characteristic Of High Speed Railway Passenger Cars

For high speed railway vehicle vibration test, the analysis of the traditional methods mainly contains the time domain, frequency domain and transfer rate. The time domain is mainly for statistical analysis of the testing vibration acceleration data. Generally it uses6s time interval to determine the average maximum value, and then evaluating the vehicle riding quality according to the standard for the vehicle dynamics. Frequency domain mainly uses the Fourier transform to get the frequency spectrogram or power spectrum, then determining the dominant frequency by the peak points. Finally based on the above analysis, we can obtain the dynamical magnification factor of the vibration energy from axle box to frame through the primary suspension, and then to car-body through the secondary suspension, further to evaluate the vehicle dynamics performance.The time-frequency analysis for the vehicle vibration test is now rarely used. As a classical analysis method, the traditional Fourier transform (FFT) has dominated the signal analysis field for long time. It can well demonstrate the frequency domain characterization of signal data, but could not give any time domain information, and is not easy to judge the dominant frequency. The short time Fourier transform (STFT) is a localized time domain analysis method based on Fourier transform, which can provide the time domain information of signal data, but can’t get rid of the disadvantage of FFT dealing with the non-stationary data. Wavelet analysis is a time-scale analysis method of signal analysis. It has a characteristic of multi-resolution with strong local frequency domain and time domain analysis ability, and overcoming the drawback of STFT time-frequency window which could not be adaptively transformed. The latest proposed HHT is the effective method of processing the non-stationary signal data in recent years. Because of the different theory and application condition of every method, each method has its advantages and disadvantages.In this paper, the vehicle system dynamic model is set up by SIMPACK software and the natural frequencies and the riding index of the vehicle system are obtained through simulation. Then the traditional analysis method and the time-frequency analysis are adopted for the data processing of vehicle line test, and the simulation results are compared, and the advantages and disadvantages of every time-frequency analysis method is summarized in dealing with vehicle vibration test data processing.