WAVELET TRANSFORM FOR CHARACTERIZING LONGITUDINAL AND LATERAL TRANSIENT VIBRATIONS OF RAILROAD TRACKS

The behavior of high-frequency transient vibrations propagating in railroad tracks is relevant to the field of long-range structural inspection of rails. While a large amount of theoretical and numerical work has been done to predict rail vibrations, experimental data have been seldom obtained due to the complex multimode and dispersive behavior of the waves. In this work a joint time-frequency analysis based on the Gabor wavelet transform is employed for measuring longitudinal and lateral vibrations propagating in a rail section in the 1000 Hz–7000 Hz range. The wavelet transform is capable of extracting both the group velocity dispersion curves and the frequency-dependent attenuation of these vibrational modes. The wavelet transform optimizes the time-frequency resolution of the dynamic signals and simply requires a single measurement point. These features make the technique well-suited for the experimental study of rail vibrations.