Lamb波在铝板缝类缺陷检测中的应用

为了研究Lamb波在缺陷板检测中的应用,建立非线性Lamb波检测系统。该系统用于检测具有不同深度裂纹的铝合金板和具有不同拉伸载荷循环的铝合金板。通过快速傅里叶变换(FFT)对获取的时域波形进行分析,得到两种缺陷对Lamb波非线性效应的影响。测试结果表明,对于裂纹缺陷,缺陷深度增加将增大试件超声非线性效应。当裂纹深度超过4 mm时,裂纹缺陷的非线性效应不会增加。对于疲劳裂纹缺陷,裂纹缺陷的出现也会加剧试件非线性效应,但是当试件疲劳断裂时,其宏观缺陷对非线性影响较小。

Application of Lamb Waves in the Detection of Aluminum Sheets with Crack-type Defects

In order to study the application of ultrasonic Lamb waves in the detection of defective plates,a nonlinear Lamb wave detection system is established.The system is used to detect aluminum alloy plates with the cracks of different depths under different cyclic tensile loadings.The acquired time-domain waveforms are analyzed by Fast Fourier Transform(FFT),and the influence of two kinds of defects on the nonlinear effects of Lamb waves is obtained.The test results show that for crack defects,deepening the defects will increase the ultrasonic nonlinear effects of the test specimens.When the crack depth exceeds 4mm,the non-linear effect of the crack defects will not increase.For fatigue crack defects,the occurrence of crack defects will also exacerbate the nonlinear effect of the test specimens.But for fatigue fracturing of the specimens,the macro defects only have a smaller effect on the nonlinearity.