超声检测换能器高次谐波的提取及应用

Extraction and application of high-order harmonic wave of ultrasonic transducer

本文研究了低频探头对高次谐波的接收特性,分析了超声换能器频带外高次谐波信号在超声检测中的应用。研究显示超声纵波直探头能够接收奇数倍基频的高次谐波信号,探头频带外区域存在大量的有用信息。由于高次谐波信号较弱且通常淹没于基频信号中,研究中采用数字信号处理方法提取探头接收的高次谐波信号,并且将其用于点焊焊核微小缺陷及薄板结构的超声检测中。高次谐振信号的提取及应用对于提高超声换能器的检测能力及检测精度、降低检测成本具有重要作用。

The receiving potential of high-order harmonic signals for a low frequency ultrasonic transducer is studied and its usability for nondestructive test is analyzed. The research indicates that a normal transducer can receive high-order harmonic signals with the frequencies of odd times of fundamental frequency ; and the signal outside the transducer bandwidth is useful in ultrasonic testing. The high order harmonic signals are weak and usually submerged in the fundamental signal. Digital signal processing method is used to extract high order harmonic signals, which can be used to test the small flaw in spot welding and steel sheet structure. The application of high order harmonic signals of transducer can not only improve the test ability and accuracy of ultrasonic transducer but also reduce test cost.