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The paper introduces steadiness evaluation indexes for running passenger car in relation to vibration data, which are non-stationary signals that its statistic characteristics vary with time and calculated by Sperling formula. Then joint time– frequency analysis is used for the post-processing of the vibration signals during calculation. The classical Fast Fourier Transformation has been applied to acceleration data in railway vehicles in order to evaluate the running steadiness performance of passenger car, but cannot provide connection between the frequency domain and the time domain. Nowadays the power of data analysis tools like the Short Time Fourier Transformation is well known and spread. It cannot only provide the characterization of the vibration signals in frequency domain, but also any information on how the frequency changes over time. As an example, the running steadiness evaluation indexes of passenger car are given for the dynamic test in the Haerbin—Dalian special passenger transport railway line. Experimental results show that the approach of Short Time Fourier Transformation can be used both to evaluate the quality of running steadiness of passenger car, and to analyze the structure of the acceleration signals generated by trains. |
