Ultrasonic Testing of the Flaw Size in the Al/Al Adhesive Structure Based on Hilbert Transform

The paper used 5 MHz and 10 MHz focusing probes to detect the adhesive aluminum plate by the method of ultrasonic water immersion feature imaging testing and imaged the feature after processing the data with Hilbert transform. The size of the artificial debonding defect in the characteristic imaging before and after transformation is measured, and the accuracy of measurement defect size is compared. The result showed that the testing quality of 10 MHz probe was better than that of 5 MHz probe,the detection rate of unglued flaw in the adhesive layer under the interface was the highest compared to the bottom wave imaging and upper interface imaging. Much better imaging result can be obtained by using 10 MHz probe and followed by processing the data with Hilbert transform. At the same time,the measurement accuracy of artificial defect size is also increased and the error is less than 5% compared with the actual flaw size. Ultrasonic feature imaging has a good detection effect on the aluminum plate adhesive layer.