Article Article
Pipe Testing with Ultrasonic Guided Wave Synthetic Focusing Techniques

Ultrasonic guided waves are routinely incorporated by industries for pipeline testing. Both guided wave energy tuning upon excitation and signal interpretation upon reception are important for discontinuity detection in pipes. Active phased array systems for long-range pipe inspection are available. Choosing active phased array or synthetic focusing is often necessary for improved testing speed, as well as overall penetration power. In this paper, two synthetic focusing techniques were utilized for discontinuity detection in a pipe. One synthetic focusing technique used time delays, while the other technique utilized a mode extraction and backpropagation scheme. Synthetic focusing techniques use either axisymmetric loading or partial loadings to generate guided waves and receive the waves by individual segments. Synthetic focusing is achieved by data analysis of the received signals, so it is faster to carry out a total focal scan for a pipeline by employing a synthetic focusing technique than by using the active focusing technique. This study shows that the time delay synthetic focusing technique yielded more accurate results for discontinuity detection and localization in a 101.6 mm steel pipe with four channels, while the back-propagation technique gave better discontinuity imaging results of a 203.2 mm steel pipe with eight channels. Both methods are useful.

References
Alleyne, D. N. and P. Cawley, “The Excitation of Lamb Waves in Pipes Using Dry Coupled Piezoelectric Transducers,” Journal of Nondestructive Evaluation, Vol. 15, 1996, pp. 11–20. Alleyne, D. N. and P. Cawley, “Long Range Propagation of Lamb Waves in Chemical Plant Pipework,” Materials Evaluation, Vol. 45, 1997, pp. 504–508. Davis, J. and P. Cawley, “The Application of Synthetic Focusing for Imaging Crack-like Defects in Pipelines Using Guided Waves,” IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency, Vol. 56, No. 4, 2009, pp. 759–771. Ditri, J. J. and J. L. Rose, “Excitation of Guided Elastic Wave Modes in Hollow Cylinders by Applied Surface Tractions,” Journal of Applied Physics, Vol. 72, No. 7, 1992, pp. 2589–2597. Gazis, D. C., “Three Dimensional Investigation of the Propagation of Waves in Hollow Circular Cylinders. I. Analytical Foundation,” Journal of the Acoustical Society of America, Vol. 31, 1959, pp. 568–573. Hayashi, T. and M. Murase, “Defect Imaging with Guided Waves in a Pipe,” Journal of the Acoustical Society of America, Vol. 117, 2005, pp. 2134–2140. Kwun, H., and H. Dynes, ‘‘Long-range Guided Wave Inspection of Pipe Using the Magnetostrictive Sensor Technology - Feasibility of Defect Characterization,’’ International Society for Optical Engineering (SPIE) on Nondestructive Evaluation of Utilities and Pipelines II (Proceedings Volume), Vol. 3398, 1998, pp. 28–34. Li, J. and J. L. Rose, “Angular-profile Tuning of Guided Waves in Hollow Cylinders Using a Circumferential Phased Array,” IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency, Vol. 49, No. 12, 2002, pp. 1720–1729. Mu, J. and J. L. Rose, “Long Range Pipe Imaging with a Guided Wave Focal Scan,” Materials Evaluation, Vol. 66, No. 6, 2008, pp. 663–666. Mudge, P. J., ‘‘Field Application of the Teletest Long-range Ultrasonic Testing Technique,’’ Insight, Vol. 43, No. 2, 2001, pp. 74–77. Rose, J. L., J. J. Ditri, A. Pilarski, J. Zhang, F. Carr and W. McNight, “A Guided Wave Inspection Technique for Nuclear Steam Generator Tubing,” Proceedings of 13th World Conference on Non-Destructive Testing, Vol. 1, 1992, pp. 191–195. Rose, J. L., “A Baseline and Vision of Ultrasonic Guided Wave Inspection Potential,” Journal of Pressure Vessel Technology, Vol. 124, 2002, pp. 273–282. Rose, J. L., Z. Sun, P. J. Mudge and M. J. Avioli, “Guided Wave Flexural Mode Tuning and Focusing for Pipe Inspection,” Materials Evaluation, Vol. 61, 2003, pp. 162–167. Wilcox, P. D., “Omni-directional Guided Wave Transducer Arrays for the Rapid Inspection of Large Area of Plate Structures,” IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, Vol. 50, No. 6, 2003, pp. 699–709.
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