Non-contact air-coupled transducers Lamb wave signal multipath effect and blind separation for different modes using PZT as receiver  

作　　者：Desheng WU Zhibo YANG Yu RUAN Wenbo LI Lijuan YANG Xuefeng CHEN 

机构地区：[1]National Key Lab of Aerospace Power System and Plasma Technology,Xi’an Jiaotong University,Xi’an 710049,China [2]School of Mechanical Engineering,Xi’an Jiaotong University,Xi’an 710049,China

出　　处：《Chinese Journal of Aeronautics》2024年第10期424-434,共11页中国航空学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(Nos.92360306,52222504 and 52241502).

摘　　要：Due to the complexity and faintness of the detection wave patterns obtained by aircoupled transducers,if it is possible to effectively separate the various modes and obtain nondispersive signals for more accurate detection and positioning,it will help to improve the accuracy and reliability of air-coupled ultrasonic Lamb wave detection,providing better technical support for the application and development of related fields.Because of the increased complexity of aircoupled signals,there is no definite theoretical formula to describe the mode changes of aircoupled signals,so the method based on blind separation has unique value.To address these challenges,the paper proposes a single-channel blind source separation(SCBSS)method.The effectiveness of this method is evaluated through simulations and experiments,demonstrating favorable separation results and efficient computational speed.This work first conducts an in-depth analysis of the signal characteristics of air-coupled ultrasonic non-destructive testing,and simulates the ultrasonic excitation conditions of air-coupled sensors through finite element software.The study of modal changes and multipath effects caused by the variation of the incidence angle of the ACT signal is carried out,and the situation of the Lamb wave signal excited by ACT at the receiving end is analyzed.By combining ACT with PZT signals,the ultrasonic signals of air-coupled Lamb waves are compared and studied,and their modal purification is carried out.

关 键 词：Air-coupled transducers Lamb wave Mode separation Blind source separation Non-destructive testing 

分 类 号：TB553[理学—物理] V25[理学—声学]