Non-contact phase coded excitation of ultrasonic Lamb wave for blind hole inspection

Jianying Tang; Wujun Zhu; Xunlin Qiu; Ailing Song; Yanxun Xiang; Fu-Zhen Xuan

doi:10.1016/j.ultras.2021.106606

Non-contact phase coded excitation of ultrasonic Lamb wave for blind hole inspection

Ultrasonics. 2022 Feb:119:106606. doi: 10.1016/j.ultras.2021.106606. Epub 2021 Oct 1.

Authors

Jianying Tang¹, Wujun Zhu², Xunlin Qiu³, Ailing Song⁴, Yanxun Xiang⁵, Fu-Zhen Xuan⁶

Affiliations

¹ Key Laboratory of Pressure Systems and Safety of MOE, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China. Electronic address: tammytjy@sina.com.
² Key Laboratory of Pressure Systems and Safety of MOE, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China. Electronic address: zhuwujun20@126.com.
³ Key Laboratory of Pressure Systems and Safety of MOE, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China. Electronic address: xunlin.qiu@ecust.edu.cn.
⁴ Key Laboratory of Pressure Systems and Safety of MOE, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China. Electronic address: ailingsong@ecust.edu.cn.
⁵ Key Laboratory of Pressure Systems and Safety of MOE, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China. Electronic address: yxxiang@ecust.edu.cn.
⁶ Key Laboratory of Pressure Systems and Safety of MOE, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China. Electronic address: fzxuan@ecust.edu.cn.

PMID: 34627027
DOI: 10.1016/j.ultras.2021.106606

Abstract

The combination of air-coupled ultrasonic testing (ACUT) and ultrasonic Lamb wave is featured with long-distance propagation and high sensitivity to discontinuities, which is a promising method for rapid and accurate inspection of plate-like materials and lightweighted structures. However, dispersive nature of Lamb wave, signal attenuation plus inevitable noises would lead to low signal-to-noise ratio (SNR). To address this problem, phase coded excitation and pulse compression technique are proposed in this paper to achieve higher SNR by over 10 dB in received signals. 13-bit and 1-carrier-period Barker code is employed as both main lobe peak and Peak Side-lobe Level (PSL) are relatively high. It is demonstrated that A0 mode Lamb wave has good localization ability for defects based on these SNR-enhanced signals. Furthermore, Damage Index (DI) and modified Reconstruction Algorithm for the Probabilistic Inspection of Damage (RAPID) are applied to realize ultrasonic imaging based defect evaluation. Results show that the imaging results agree well with the actual artificial defects in terms of size and shape. Lamb-wave-based air-coupled ultrasonic testing, combined with DI and ultrasonic imaging algorithm, could be a potential way in the NDT of lightweighted structures.

Keywords: Air-coupled ultrasonic testing; Lamb wave; Modified RAPID; Phase coded excitation; Simulation.