Long range guided wave testing of pipe is becoming commonplace today in serving as an excellent screening tool. Recent concerns, however, are associated with reduced penetration power due to viscoelastic coatings and soil loading of buried pipes. This paper discusses the problem and some new approaches to improve penetration power concerns via phased array focusing, natural focusing and frequency tuning. Preliminary experimental efforts will be presented for various coatings and soil types showing an influence on axisymmetric wave propagation. Discussions of instrumentation and actuator and sensor parameters along with a few sample results on discontinuity detection and sizing are presented.
Alleyne, D.N. and P. Cawley, “Long Range Propagation of Lamb Waves in
Chemical Plant Pipework,” Materials Evaluation, Vol. 45, 1997, pp. 504–508.
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 Control, Vol. 49, 2002, pp. 1720–1729.
Mu, J. and Joseph L. Rose, “Long Range Ultrasonic Guided Wave Focusing
in Pipe Using a Phased-Array System,” Review of Progress in Quantitative
Nondestructive Evaluation, Vol. 26A, D.O. Thompson and D.E. Chimenti,
eds., Melville, New York, AIP, 2006, pp. 158–162.
Mu, J. and J.L. Rose, “Long Range Pipe Imaging with a Guided Wave Focal
Scan,” Materials Evaluation, Vol. 66, 2008, pp. 663–666.
Rose, J.L., Ultrasonic Waves in Solid Media, Cambridge, Cambridge University
Press, 1999.
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., J. Mu and J.K. Van Velsor, “New Directions in Guided Wave
Pipe Testing,” Materials Evaluation, Vol. 65, 2007, pp. 375–378.
Thompson, R.B., G.A. Alers and M.A. Tennison, “Application of
Direct Electromagnetic Lamb Wave Generation to Gas Pipeline
Inspection,” Proceedings of the IEEE Ultrasonic Symposium, 1972,
pp. 91–94.
Zhang, L., J.L. Rose and B.J. Gavigan, “Natural Focusing Inspection for
Pipes by Frequency Tuning,” Proceedings of QNDE, Vol. 24, 2004, pp.
1557–1562.