The 24th International Workshop on Electromagnetic Nondestructive Evaluation (ENDE2019)

271 / 2019-11-27 17:36:25

High Resolution Rail Damage Imaging Method Based on Dispersion Compensation

Li Xina, Wang haitao a，Tian Guiyun a ,Dong Zeyua, Jiang Yia

Plenary track > Imaging, signal and image processing

Lamb wave is a kind of ultrasonic guided wave propagating in plate structure. It has a long
propagation distance, slow attenuation and is sensitive to surface defects. It has been widely used in structural
health monitoring. However, the dispersion characteristics of Lamb wave make the Lamb wave packet distort
when it propagates in the object, which leads to the error in calculating the arrival time of the wave packet
and seriously affects the location accuracy of the defect. In addition, in practical engineering, the boundary
reflection wave of the inspected object is easy to overlap with other wave packets, which increases the
difficulty of Lamb wave analysis. In view of the long lateral distance and short longitudinal distance of rail,
The linear compensation of dispersion curve is used to correct the distortion of Lamb wave in the process of
propagation, and the arrival time of damaged reflection wave is corrected to improve the positioning
accuracy. On this basis, the larger range resolution is obtained by compressing the excitation signal. The
relative error of damage location at the rail waist is reduced to 1%~5%.