基于希尔伯特变换的铝/铝胶接结构缺陷尺寸的超声测量

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

采用5 MHz和10 MHz的聚焦探头对胶接铝板进行超声水浸特征成像检测,以及对扫查数据进行Hilbert(希尔伯特)变换后的特征成像,测量了变换前后的人工脱粘缺陷尺寸,并比较了测量精度。试验结果表明:10 MHz探头检测结果比5 MHz探头的检测结果更好;对粘接层下界面成像与底波成像以及粘接层上界面成像进行对比,脱粘缺陷的检出率更高;10 MHz扫查特征成像经Hilbert变换可得到更好的成像结果,人工缺陷尺寸的测量精度进一步提高,测量结果相比实际缺陷尺寸的误差不大于5%。超声特征成像对铝板胶接层有很好的检出效果。

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.