Abstract:
Ultrasonic guided wave technique has shown its great potential for pipeline testing in petroleum and power industries. However, the sensitivity and identification precisi...Show MoreMetadata
Abstract:
Ultrasonic guided wave technique has shown its great potential for pipeline testing in petroleum and power industries. However, the sensitivity and identification precision for small defects still needs to be further improved. The single-point signal obtained by conventional methods utilizing fixed transducers contains limited information for defect identification, while interference modes cannot be always completely removed. This article develops an enhanced long-range guided-wave pipe inspection method based on 2-D signal acquisition and processing with local axial scan, to improve the detecting ability for a small size defect. The local-scanning time-space ( t - x ) domain wavefield data is analyzed and filtered in the frequency-wavenumber ( f - k ) domain and enhanced with virtual focusing in the time domain. In the f - k domain, a narrow-band filter of high-order 2-D Gaussian-type window is employed to eliminate interference mode components. To simplify the scan process while ensuring acceptable identification of defects, optimization on scan parameters is studied based on finite element method (FEM) numerical simulation. Finally, axial scan experiments using flexible electromagnetic acoustic transducer (EMAT) indicate the effectiveness for identifying small defects.
Published in: IEEE Transactions on Instrumentation and Measurement ( Volume: 72)