Pulse compression of guided wave by airborne ultrasound excitation for improving defect detection accuracy in concrete

Abstract

Scanning airborne ultrasound source technique has been developed as a safe and simple non-contact non-destructive inspection method. This method enables non-contact excitation of guided waves by using high-intensity airborne ultrasonic waves. However, the airborne ultrasound source that can generate high intensity airborne ultrasounds use resonance drive, so the sound waves are emitted for a long time. As a result, the inspection results become complicated, and the inspection accuracy decreases. To solve this problem, we proposed a pulse compression using chirp signals of guided waves generated by airborne ultrasound. In this paper, we investigated the pulse compression of guided waves generated in mortar samples using an airborne ultrasound source driven by a chirp signal. As a result, it was confirmed that the visualization accuracy of defects was improved by pulse compression.

Visualization of slit defect by scanning nonlinear airborne ultrasound source technique using compressed sensing

“…High-speed scanning similar to SLS can also be achieved by using an airborne ultrasound phased array. [27][28][29] To visualize the propagation of Lamb waves in the SAS method, the propagation waveform from the wave source is measured at each position within the measurement area. The testing time of the scanning wave source technique depends on the wave source scanning speed 19,27) and number of measurement points.…”

Non-destructive testing of metal plates by guided wave propagation image using scanning sound source technique and airborne ultrasound phased array with suppressed grating lobe generation

“…However, this technique uses a focused airborne ultrasound source that is scanned mechanically, and thus there is an upper limit to the scanning speed, resulting in long measurement times. To decrease the measurement time, the use of an airborne ultrasound phased array (AUPA) [14,15], which performs electronically controlled wave source scanning, has been investigated [16][17][18][19][20][21][22][23]. An AUPA is a sound source in which multiple ultrasound emitters are arranged in a lattice.…”