Defect detection and location in switch rails by acoustic emission and Lamb wave analysis: A feasibility study

• An acoustic emission based approach for defect detection in railroad tracks.
• Frequency analysis is employed to identify defects.
• Continuous wavelet transform is used to analyze the wave dispersion and locate defects.
• The technique is not limited by the cross-section dimension or the location of defects.
• Only one sensor is needed for defect identification and location.

An acoustic emission (AE) based approach is proposed in this study to identify and locate newly initiated defects or the propagation of existing defects in railroad switch rails. Defect-induced AE signals are identified through frequency analysis, as frequencies of these signals are much higher than those induced by structural vibration. Continuous wavelet transform (CWT) is employed to analyze the Lamb wave dispersion of the detected signal, so that two characteristic points can be selected on the CWT contour map to locate the defect. Using this approach, defects in a damaged switch rail can be located using a single sensor.