基于空耦超声Lamb波的金属板状结构内部缺陷检测方法

针对接触式超声检测方法在金属板结构内部缺陷实际工程检测中存在的环境要求高、效率低、操作难度高等问题,提出了空耦超声Lamb波检测方法,该方法能更好地适应现场应用环境,提高检测效率,减少传感器数量。通过有限元仿真和实验分析比较了空耦超声检测与接触式超声检测两种方法接收到的信号和成像效果。结果表明:有限元仿真和实验中,空耦超声检测方法对缺陷位置的定位误差分别为2 mm和3.6 mm,接触式检测方法对缺陷位置的定位误差分别为2 mm和11.3 mm,空耦检测具有较高的定位精度;单侧激励条件下,适合采用A0模态Lamb波对板内缺陷进行检测;空耦超声检测可以通过调整信号接收角度接收单一模态Lamb波,避免伪像产生。该方法为后续金属板状结构内部缺陷的空耦超声检测提供参考。

Detection of internal defect in metal plate structures using air-coupled ultrasonic Lamb waves

Aiming at the problems of high environmental requirements, low efficiency and high operational difficulty of the contact ultrasonic detection method in the actual engineering detection of defects in the metal plate structures, the Lamb wave detection method of air-coupled ultrasonic was proposed, which can better adapt to the field application environment, improve the detection efficiency and reduce the number of sensors. The finite element simulation and experimental analysis are compared to compare air-coupled ultrasonic testing and the contact ultrasonic testing methods for receiving signals and imaging effects. The results show that In the finite element simulation and experiment, the positioning error of the air-coupled ultrasonic detection method to the defect position is 2mm and 3.6mm respectively, and the positioning error of the contact detection method to the defect position is 2.24mm and 11.3mm respectively. The air-coupled detection has a high positioning accuracy. Under the one-side excitation condition, the A0 mode of Lamb wave used to detect the defects in the board is suitable; the air-coupled ultrasonic detection can receive the single mode Lamb wave by adjusting the signal receiving angle to avoid artifact generation.