Guided wave inspection potential of defects in rail

The authors provide the results of experiments they have conducted on rail at test tracks and on an operating railroad. Results are presented that suggest that the frequency range [40,80]kHz readily supports guided waves. Theoretical results including roots of the dispersion relations for rail and a sample of wave displacement within a railhead are presented. Non-contact air-coupled and electromagnetic acoustic transducers (EMATs) are discussed as receivers of sound energy emanating from rail. The results of an experiment that used air-coupled transducers to profile the radiation pattern of a rail are presented. A rail cutting experiment with EMATs that simulated a transverse rail defect is discussed. Conclusions that the authors have drawn from their work are summarized at the end of the paper.