基于Lamb波的污垢厚度检测

Detecting Fouling Layer Thickness Based on Lamb Wave

首先在理论上分析超声导波在污垢中传播的特点,推导出超声导波在污垢中传播时会发生声强衰减和群速度降低的现象。然后利用波结构分析方法选择出适合污垢检测的A0、S1、S2模态,最后利用1.00MHz和2.25MHz超声导波探头进行导波污垢检测实验。通过实验可得,在激发声强大于35d B的情况下,可以使用上述模态进行污垢检测,通过检测结果可以计算出污垢平均厚度。

The characteristics of ultrasonic guided wave's propagation in the dirt were analyzed theoretically and the acoustic intensity attenuation and group velocity decrease incurred by the ultrasonic wave's transmission in the dirt were derived,then having wave structure analysis method adopted to select AO,S1 and S2 modes applicable to the dirt detection. Experiment on applying both 1. 00 MHz and 2. 25 MHz ultrasonic guided wave probes to detect the fouling shows that when the excitation intensity exceeds 35 d B,the above-said mode can be adopted to detect the dirt; and the average thickness of the dirt can be estimated upon the detection results