In this paper, the Lamb type EMAT transducers are simulated using Finite Element technique. The characteristics of scattering from defects and shelling are also explored. The absolute values of U2 (vertical displacement of the rail) of transmitted waves are monotonically decreased with the crack depth for 60 kHz Lamb wave. For 175 kHz Lamb wave can not distinguish the shelling and the crack. The absolute values of U2 of transmitted waves show the big difference between defects without shelling and no defect without shelling for 175 kHz Lamb waves. The experiments for hole defect in a clean and rough rail were performed in the Laboratory. To generate guided waves and to receive reflected waves from the defects, the Lamb type EMATs with four different frequencies (60 kHz, 100 kHz, 185 kHz, and 280 kHz) were used in a pulse-echo mode. The guided waves with higher frequency (185 kHz and 280 kHz) are sensitive to the surface roughness of the rail head because the most of energy is concentrated in the top surface of the rail head. Therefore, the best condition in detecting a transverse defect under a shelling is the guided waves with lower frequencies (60 kHz and 100 kHz).
Rail inspection with guided waves
Schienenprüfung mit geführten Schallwellen
2006
5 Seiten, 11 Bilder, 11 Quellen
Aufsatz (Konferenz)
Englisch
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