Resumo

FLOREZ, Elkin; CARDONA, Salvador  e  JORDI, Lluïsa. Selecting the temporal window in the short time Fourier transforms used in the vibration signal analysis to determine flats at train's wheels. Rev.fac.ing.univ. Antioquia [online]. 2009, n.50, pp.145-158. ISSN 0120-6230.

One of the most typical problems in the wheels rail is the presence of flats. They can generate sufficient impact to cause bad operation of the train. Early detection of flat wheels allows the necessary corrections (turning surface of the wheel) before they cause serious damage to components of the train and degrade the performance of services to users. Although there are many vibration sensors in the market to detect vibrations, generated by the pass of a train, there are not powerful tools to detect the presence of flats on the wheels of the train, through analysis of these signals. This study presents the appropriate selection of the temporal window to use the Short Time Fourier Transform (STFT) in the analysis of vibration signals taken at the foot of the rail and generated by the pass of the train, which allows to determine the presence of these flats. To do this, a signal, using Matlab, was built to simulate the presence of flats and for knowing how the STFT, implementing different window functions (Rectangular, Gaus, Hanning, Chebyshev), reflects the presence of it, in both time and frequency domain. Finally, the STFT is implemented to real signals. The results show that the STFT is an effective tool to detect the presence of flats at the rail wheels wheter the temporal window and its parameters are properly selected to perform a timefrequency analysis.

Palavras-chave : Rail wheel flat; short time fourier transform; temporal window; vibration signal.

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