A new experimental analysis method has been developed for analyzing propagating waves in effectively infinite structures. Very little prior knowledge is required of the form of these waves, although the choice of mesh size can be optimized by knowledge of the likely range of wavenumbers. Application of this method to railway track allows one vertical and three lateral propagating waves to be clearly identified, and their wavenumbers determined as a function of frequency up to 5 kHz. The deformed shapes and decay rates of each wave along the rail could also be measured. The cut-on frequencies of the vertical bending, lateral bending and torsional waves are in the range 200 - 500 Hz, depending on the fastener stiffness. The third lateral wave, which consists of bending of the web, cuts on at around 1,7 kHz for UIC 54 rail and 1,4 kHz for UIC 60 rail independently of fastener stiffness. The deformed shapes of each wave are frequency-dependent, making classification difficult; the measured shapes agree well with predictions, however. Higher order waves which are predicted to cut on at around 5 kHz in both lateral and vertical directions were not identified clearly in the measurements, probably due to the choice of excitation position. The chosen mesh was only just sufficient for analysis of waves in the track up to 5 kHz, with some aliasing occurring above this frequency, indicating that a closer spacing would be desirable here. A longer mesh is required where the attenuation is lower than about 0,5 dB/m, which occurs for some of the lateral results. The number of measurement cross-sections determines the maximum number of waves which can be resolved, and this was more than enough. Additional excitation positions, for example on the web or foot, could be used to ensure that all waves are identified, but the results found are the most relevant for excitation due to wheel/rail contact.
Experimental analysis of wave propagation in railway tracks
Experimentelle Analyse der Wellenausbreitung in Eisenbahnschienen
Journal of Sound and Vibration ; 203 , 5 ; 867-888
1997
22 Seiten, 21 Bilder, 1 Tabelle, 16 Quellen
Aufsatz (Zeitschrift)
Englisch
Experimental analysis of wave propagation in railway tracks (sv970903)
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