Long Range Inspection of Rail-Break Using Ultrasonic Guided Wave Excited by Pulse String

Compared with single pulse excitation mode, ultrasonic guided wave excited by pulse string is more suitable for long range inspection of rail-break. Shear horizontal (SH) guided wave transducers with modified structure and pulse string emission circuit were designed for the purpose of achieving longer inspection distance. To solve the control difficulty of pulse string, the pulse string phase shift superposition (PSPSS) theorem was proposed and exhaustive algorithm together with genetic-like algorithm were also given to calculate the optimal phase shift parameters. Experiments of pulse string guided wave on rail were carried out. Result shows that the PSPSS theorem can improve wave energy significantly, and the maximum propagation distance of pulse string guided wave can be enhanced up to more than 600 meters.