基于合成孔径聚焦的超声SH导波成像检测

超声水平剪切(shear horizontal,SH)导波成像检测旨在解决平板检测中检测距离增加时分辨力降低的问题。该文运用合成孔径聚焦原理,构建了16通道超声SH导波成像检测实验系统,通过分析阵列信号时频域特征揭示了声波与缺陷间相互作用的规律,对SH导波合成孔径聚焦成像算法进行了讨论,阐明了导波阵列信号时空域信息合成在聚焦成像中的应用。研究结果表明:合成孔径聚焦可用于超声SH导波成像检测,所成图像能够表征钢板中检测距离2 m以上、尺寸当量大于5 mm的缺陷信息,为深入开展工业在役大尺度结构板材的缺陷成像检测和结构健康监测提供了基础。

Imaging and inspection of ultrasonic SH guided wave by synthetic aperture focusing

Systems are needed to identify steel plate defects at long distances.An inspection and imaging system with 16 channels of ultrasonic shear horizontal(SH) guided waves was developed based on the theory of synthetic aperture focusing for long distance inspections.Time and frequency domain analyses were used to study the interactions between the ultrasound signals and defects.An aperture focusing and imaging algorithm was developed for the SH-guided waves using space-time domain information for focusing and imaging of the array signals.The imaging experiment shows that aperture focusing can be used for imaging of ultrasonic SH-guided waves for plate inspections and that the images can identify defects with φ5 mm more than 2 m from steel plates.This method provides defect inspection and structural monitoring of large industrial plates in-situ.