Journal of the Korean Society for Nondestructive Testing (비파괴검사학회지)

The Korean Society for Nondestructive Testing (한국비파괴검사학회)
권호 표지

Development of an Array of EMAT for a Long-Range Inspection of a Pipe Using a Torsional Guided Wave

  • Cheong, Yong-Moo (Nuclear Materials Research Center, Korea Atomic Energy Research Institute) ;
  • Jung, Hyun-Kyu (Nuclear Materials Research Center, Korea Atomic Energy Research Institute)
  • Published : 2007.06.30
Download PDF
⟨ Previous Next ⟩

Abstract

A torsional guided wave mode in a tubular structure has many advantages in obtaining a higher sensitivity and lower attenuation for a defect, because it shows no dispersion characteristics and no radial displacement for a tubular structure. Many attempts have been made to excite and receive torsional guided waves by conventional piezoelectric transducers, but only a few examples are used during a practical field inspection. In this study, an array of electromagnetic acoustic transducers (EMATs) were for an excitation and reception of the torsional guided waves in a pipe was designed and fabricated. The signal patterns were analyzed based on various beam path length. The feasibility of detecting the defects was investigated through a series of experiments with artificial notches on a pipe.

Keywords

References

  1. Ahn, B. Y., Kim, Y. J., Kim, Y. G. and Lee, S. S. (2004) Development of an EMAT System for Detecting Flaws in Pipeline. J. Korean Soc. NDT, Vol. 24, No. 1, pp. 15-21
  2. Alers, G. A. and Burns, L. R. (1987) EMAT Designs for Special Applications, Mater. Eval., Vol. 45, pp. 1184-1189
  3. Alleyne, D. N. and Cawley, P. (1996) The Excitation of Lamb Waves in Pipes Using Dry-Coupled Piezoelectric Transducers, J. NDE, Vol. 15, No. 1, pp. 11-20
  4. Cheong, Y. M., Lee, D. H. and Jung, H. K. (2004) Ultrasonic Guided Wave Parameters for Detection of Axial Cracks in Feeder Pipes of PHWR Nuclear Power Plants, Ultrasonics, Vol. 42, pp. 883-888 https://doi.org/10.1016/j.ultras.2004.01.073
  5. Ditri, J. J. and Rose, J. L. (1992) Excitation of Guided Elastic Wave Modes in Hollow Cylinders by Applied Surface Tractions, J. Appl. Phys., Vol. 72, No. 7, pp. 2589-2597 https://doi.org/10.1063/1.351558
  6. Gazis, D. C. (1959) Three Dimensional Investigation of the Propagation of Waves in Hollow Circular Cylinders, I. Analytical Foundation, J. Acoust. Soc. Am., Vol. 31, No. 5, pp. 568-573 https://doi.org/10.1121/1.1907753
  7. Hirao, M. and Ogi, H. (1999) An SH wave EMAT Technique for Gas Pipeline Inspection, NDT & E Int., Vol. 32, pp. 127-132 https://doi.org/10.1016/S0963-8695(98)00062-0
  8. Kim, J. D. and Kwon, D. S. (2003) Vibration Characteristics of Piezoelectric Torsional Transducers, J, Sound & Vibration Vol. 24, No. 2, pp. 453-473
  9. Kwun, H. and Bartels, K. A. (1996) Experimental Observation of Elastic-Wave Dispersion in Bounded Solids of Various Configuration, J. Acoust. Soc. Am., Vol. 99, No. 2, pp. 962-968 https://doi.org/10.1121/1.414624
  10. Rose, J. L. (1999) Ultrasonic Waves in Solid Media, Cambridge University Press, pp. 96
  11. Shin, H. J. and Rose, J. L. (1998) Guided Wave Tuning Principles for Defect Detection in Tubing, J. NDE, Vol. 17, No. 1, pp. 27-36
  12. Thompson, R. B. (1978) A Model for the Electromagnetic Generation of Ultrasonic Guided Waves in Ferromagnetic Metal Polycrystals, IEEE Trans. Sonics & Ultrasonics, Vol. SU-25(1), pp. 7-15