Long-range inspection of a pipe with a bend using microwaves

Article type: Research Article

Authors: Uoshita, Shoya^a | Sasaki, Kota^a | Katagiri, Takuya^a | Yusa, Noritaka^a; | Hashizume, Hidetoshi^a

Affiliations: [a] Department of Quantum Science and Energy Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi, Japan

Correspondence: [*] Corresponding author: Noritaka Yusa, 6-6-01-2, Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi, 980-8579, Japan. E-mail: [email protected]

Abstract: This study evaluated the effect of bends on the long-range nondestructive testing inspection of pipe surfaces based on microwaves propagating inside the pipe. Three-dimensional finite element simulations were conducted to reveal electromagnetic fields at bends with a diameter of 23 mm and various radii of curvature when microwaves were emitted into a pipe in the TM01 mode that had been mainly used in earlier studies. The simulations revealed that the effect of the bend on the microwaves is not significant when the ratio of curvature is larger than approximately 2, whereas in general a bend reflects a part of microwaves and causes non-TM01 modes. Subsequent experimental verifications, which used a pipe with a total length of approximately 4 m and a 90-degree or 180-degree bend, confirmed clear reflections due to artificial wall thinning in spite of the presence of the bend.

Keywords: Electromagnetic nondestructive evaluation, wall thinning, pipe degradation, time of flight, electromagnetic wave, finite element simulation

DOI: 10.3233/JAE-171001

Journal: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 4, pp. 1519-1526, 2019