Abstract
The development of a dry-coupled piezoelectric transducer system for the detection of corrosion in chemical plant pipework using cylindrical Lamb waves is described. It is shown that the axisymmetricL(0,2) mode at a frequency of about 70 kHz is an attractive mode to use for longdistance propagation. The results show that a ring of piezoelectric length-expander elements can be used to excite theL(0,2) mode and to suppress all the nonaxisymmetric modes. Tests have been carried out both with the piezoelectric elements bonded to the pipe and fabricated into a simple transducer which was clamped against the pipe. The performance of the dry-coupled system was very similar to that of the bonded elements. In pulse echo tests, the noise floor obtained with the dry-coupled system was less than 1% of the amplitude of the propagatingL(0,2) mode. The drycoupled transducers provide a simple, light, readily detachable system for the long-range inspection of pipework.
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References
M. G. Silk and K. F. Bainton, The propagation in metal tubing of ultrasonic wave modes equivalent to Lamb waves,Ultrasonics,17:11–19 (1979).
E. Lehfeldt and P. Höller, Lamb waves and lamination detection,Ultrasonics,5:255–257 (1967).
D. F. Ball and D. Shewring, Some problems in the use of Lamb waves for the inspection of cold-rolled steel sheet coil,Nondestr. Testing,6:138–145 (1976).
T. L. Mansfield, Lamb wave inspection of aluminium sheet,Mater. Eval. 33:96–100 (1975).
S. I. Rokhlin, Interaction of Lamb waves with elongated delaminations in thin sheets,Int. Adv. NDT,6:263–285 (1979).
S. I. Rokhlin and F. Bendec, Coupling of Lamb waves with the aperture between two elastic sheets,J. Acoust. Soc. Am.,73:55–60 (1983).
J. L. Rose, M. C. Fuller, J. B. Nestleroth, and V. H. Jeong, An ultrasonic global inspection technique for an offshore K-Joint,J. Soc. Petro. Eng.,23:358–364 (1983).
P. M. Bartle, Acoustic pulsing for in-service monitoring, inNonDestructive Testing (Proc 12th World Conference), J. Boogard and G. M. van Dijk, eds. (Elsevier Science Publishers B. V., Amsterdam, 1989), pp. 254–257.
W. Böttger, H. Schneider, and W. Weingarten, Prototype EMAT system for tube inspection with guided ultrasonic waves,Nucl. Engin. Design,102:356–376 (1987).
W. Böttger, H. Schneider, and W. Weingarten, Tube inspection with an EMAT using guided ultrasonic waves,Proc 4th Eur. NDT Conf. 4:2305–2313 (Pergamon Press, 1987).
J. J. Ditri, J. L. Rose, and A. Pilarski, Generation of guided waves in hollow cylinders by wedge and comb type transducers, inReview of Progress in Quantitative NDE, Vol. 12, D. O. Thompson and D. E. Chimenti, eds. (Plenum Press, New York, 1993), pp. 211–218.
J. L. Rose, J. J. Ditri, A. Pilarski, K. Rajana, and F. T. Carr, A guided wave inspection technique for nuclear steam generator tubing,NDT E. Int.,27:307–330 (1994).
A. C. Duncumb and D. M. Keighley, Inspection of titanium tubing using ultrasonic Lamb waves generated by an electromagnetic acoustic transducer,Proc 4th Eur. NDT Conf.,4:2228–2236 (Pergamon Press, 1987).
M. V. Brook, T. D. K. Ngoc, and J. E. Eder, Ultrasonic inspection of steam generator tubing by cylindrical guided waves, inReview of Progress in Quantitative NDE, Vol. 9, D. O. Thompson and D. E. Chimenti, eds. (Plenum Press, New York, 1990), pp. 243–249.
W. Mohr and P. Höller, On inspection of thin walled tubes for transverse and longitudinal flaws by guided ultrasonic waves,IEEE Trans. Sonics Ultrasonics,SU-23:369–374 (1976).
R. B. Thompson, G. A. Alers, and M. A. Tennison, Application of Direct Electromagnetic Lamb Wave Generation to Gas Pipeline Inspection, Proc. IEEE Ultrasonic Symposium, Boston, Oct 4–7, 1972, pp. 91–94.
G. A. Alers and L. R. Burns, EMAT designs for special applications,Mater. Eval.,45:1184–1189 (1987).
G. A. Alers, Application of Special Wave Modes to Industrial Inspection Problems, Proc. 1994 ASME Winter Meeting, Symposium on Wave Propagation and Emerging Technologies, Chicago, Illinois, Nov. 6–11, 1994.
D. N. Alleyne and P. Cawley, Optimisation of Lamb wave inspection techniques,NDT E Int. 25:11–22 (1992).
D. N. Alleyne and P. Cawley, The practical excitation and measurement of Lamb waves using piezoelectric transducers, inReview of Progress in Quantitative NDE, Vol. 13, D. O. Thompson and D. E. Chimenti, eds. (Plenum Press, New York, 1994), pp. 181–188.
D. C. Gazis, Three-dimensional investigation of the propagation of waves in hollow circular cylinders. I. Analytical foundation; II. Numerical results,J. Acoust. Soc. Am.,31:568–578 (1959).
K. F. Graff,Wave Motion in Elastic Solids (Clarendon Press, Oxford, 1975).
M. J. S. Lowe, Matrix techniques for modelling ultrasonic waves in multilayered media,IEEE Trans Ultrasonics, Ferroelectrics Frequency Control,42 (in press).
M. G. Silk,Ultrasonic Transducers for Nondestructive Testing (Adam Hilger, Bristol, 1984).
E. J. Owens, Automatic transmit-receive switch uses no relays but handles high power,J. Acoust. Soc. Am.,68:712–713 (1980).
D. N. Alleyne, and P. Cawley, The long range detection of corrosion in pipes using Lamb waves, inReview of Progress in Quantitative NDE, Vol. 14, D. O. Thompson and D. E. Chimenti, eds. (Plenum Press, New York, 1995), pp. 2073–2080.
D. N. Alleyne, M. J. S. Lowe, and P. Cawley, The long range detection of corrosion in pipes using Lamb waves, inReview of Progress in Quantitative NDE, Vol. 15, D. O. Thompson and D. E. Chimenti, eds. (Plenum Press, New York, in press).
D. N. Alleyne and P. Cawley,Long Range Propagation of Lamb Waves in Chemical Plant Pipework (submitted for publication).
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Alleyne, D.N., Cawley, P. The excitation of Lamb waves in pipes using dry-coupled piezoelectric transducers. J Nondestruct Eval 15, 11–20 (1996). https://doi.org/10.1007/BF00733822
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DOI: https://doi.org/10.1007/BF00733822