An ultrasonic testing method of multi-layer adhesive joint based on wavelet analysis

In order to detect the debond defect of multilayer metal-rubber adhesive joint, the mature ultrasonic detecting technique was used. By rebuilding an existent ultrasonic detecting instrument and utilizing a high speed data acquisition card and LabVIEW developing environment, an ultrasonic signal acquisition and analysis platform was successfully built. Echo signal acquisition was programmed. The signal was decomposed and reconstructed by utilizing db7 wavelet in Matlab script node of LabVIEW. A contrast experiment was carried out on two specimens which have debond defect. The result shows that the reconstructed signals are remarkably different between the well-bonded areas and the debonded areas, which indicates that the wavelet analysis method is effective in detecting the debond defect under the first rubber layer.