Research on Improving Detection of Longitudinal Multiple Defects by Dual-layer Virtual Source Imaging

Aiming at the difficulty of detecting the depth of the internal defects in the longitudinal region of the heavy haul and high speed rail welds, this paper studies a technique of ultrasonic virtual source imaging for detecting internal defects in dual-layer media. The numerical simulation model of phased-array sub-aperture virtual source ultrasonic transmission and receiving in dual-layer medium was established by Snell's rule. The experimental verification was carried out to realize the accurate detection of internal defects of a series longitudinal distribution in the standard test block. The results show that the algorithm can effectively improve the detection rate of multiple defects in the longitudinal distribution of standard test block and significantly increase the signal-to-noise ratio.