Journal of the Korean Society for Nondestructive Testing (비파괴검사학회지)

The Korean Society for Nondestructive Testing (한국비파괴검사학회)
권호 표지

A Brazing Defect Detection Using an Ultrasonic Infrared Imaging Inspection

초음파 열 영상 검사를 이용한 브레이징 접합 결함 검출

  • Cho, Jai-Wan (Nuclear Industry Robotics Lab., Korea Atomic Energy Research Institute) ;
  • Choi, Young-Soo (Nuclear Industry Robotics Lab., Korea Atomic Energy Research Institute) ;
  • Jung, Seung-Ho (Nuclear Industry Robotics Lab., Korea Atomic Energy Research Institute) ;
  • Jung, Hyun-Kyu (Nuclear Industry Robotics Lab., Korea Atomic Energy Research Institute)
  • 조재완 (한국원자력연구원 원자력로봇Lab.) ;
  • 최영수 (한국원자력연구원 원자력로봇Lab.) ;
  • 정승호 (한국원자력연구원 원자력로봇Lab.) ;
  • 정현규 (한국원자력연구원 원자력로봇Lab.)
  • Published : 2007.10.30
Download PDF
⟨ Previous Next ⟩

Abstract

When a high-energy ultrasound propagates through a solid body that contains a crack or a delamination, the two faces of the defect do not ordinarily vibrate in unison, and dissipative phenomena such as friction, rubbing and clapping between the faces will convert some of the vibrational energy to heat. By combining this heating effect with infrared imaging, one can detect a subsurface defect in material in real time. In this paper a realtime detection of the brazing defect of thin Inconel plates using the UIR (ultrasonic infrared imaging) technology is described. A low frequency (23 kHz) ultrasonic transducer was used to infuse the welded Inconel plates with a short pulse of sound for 280 ms. The ultrasonic source has a maximum power of 2 kW. The surface temperature of the area under inspection is imaged by an infrared camera that is coupled to a fast frame grabber in a computer. The hot spots, which are a small area around the bound between the two faces of the Inconel plates near the defective brazing point and heated up highly, are observed. And the weak thermal signal is observed at the defect position of brazed plate also. Using the image processing technology such as background subtraction average and image enhancement using histogram equalization, the position of defective brazing regions in the thin Inconel plates can be located certainly.

고에너지 초음파 여기 탄성파가 물체의 균열, 박리 등의 결함 부위를 통과할 때 서로 맞닿은 결함면은 균일하게 진동하지 않는다. 초음파 입사에 따른 결함 면 사이의 마찰(friction), 문지름 (rubbing) 또는 부딪침(clapping) 에 의해 진동 에너지가 결함 부위에서 국부적인 열로 변환된다. 이를 적외선 열 영상 카메라로 관측하면 구조물의 결함을 실시간으로 검출할 수 있다. 본 논문에서는 초음파 열 영상 검사를 이용한 인코넬 합금 박판의 브레이징 접합 결함 검출에 대해 기술한다. 2 kW 의 전력과 23 kHz 대역의 가진 주파수를 갖는 초음파 펄스를 280 ms 기간 동안 인코넬 합금의 브레이징 접합 박판에 입사시켰다. 브레이징 접합부의 결함위치 부근의 인코넬 합금 박판의 양면이 맞닿은 경계선에서 아주 밝은 국부적인 발열(핫 스팟)이 적외선 열 영상 카메라에 의해 관측되었으며 브레이징 접합 결함 위치에서도 미약한 열이 관측되었다. 배경 감산 평균 및 히스토그램 평활화 처리 등의 영상처리를 통해 브레이징 접합의 결함을 확인하였다.

Keywords

References

  1. R. B. Mignogna, R. E. Green Jr., J. C. Duke Jr., E. G. Henneke II and K. L. Reifsnider, 'Thermographic investigation of high-power ultrasonic heating in materials,' Ultrasonics, Vol. 19, pp. 159-163, (1981) https://doi.org/10.1016/0041-624X(81)90095-0
  2. L. D. Favro, R. L. Thomas, X. Han, Z. Ouyang, G. Newaz and D. Gentile, 'Sonic infrared imaging of fatigue cracks,' Int. Journal of Fatigue, Vol. 23, pp. 5471-5476, (2001)
  3. L. D. Favro, X. Han, Z. Ouyang, G. Sun, H. Sui and R. L. Thomas, 'Infrared imaging of defects heated by a sonic pulse,' Rev. Sci. Instrum., Vol. 71, pp. 2418-2421, (2000) https://doi.org/10.1063/1.1150630
  4. X. Han, L. D. Favro and R. L. Thomas, 'Recent developments in sonic IR imaging,' Review of Quantitative Nondestructive Evaluation, Vol. 22, pp. 500-504, (2003)
  5. T. Zweschper, G. Riegert, A. DiIlenz and G. Busse, 'Ultrasound burst phase thermography (UBP) for applications in the automotive industry,' AlP Conference Proceedings, Vol. 657, pp. 531-536, (2003)
  6. G. Busse, A. DiIlenz, and T. Zweschper, 'Defect-selective imaging of aerospace structures with elastic-wave-activated thermography,' SPIE, Vol. 4360, pp. 580-586, (2001) https://doi.org/10.1117/12.421043
  7. J. C. Chen, J. Kephart and W. T. Riddell, 'A parametric study of crack propagation during sonic IR inspection,' Review of Quantitative Nondestructive Evaluation, Vol. 25. pp. 1577-1584, (2006)
  8. X. Han, V. Loggins, Zhi Zeng, L. D. Favro and R. L. Thomas, 'Mechanical model for the generation of acoustic chaos in sonic infrared imaging,' Appl. Phys. Lett., Vol. 85, No.8, pp. 1332-1334, (2004) https://doi.org/10.1063/1.1785285
  9. X. Han, Z. Zeng, W. Li. S. Islam. J. Lu, V. Loggins, E. Yitamben, L. D. Favro, G. Newaz and R. L. Thomas, 'Acoustic chaos for enhanced detectability of cracks by sonic infrared imaging,' J. App!. Phys., Vol. 95, No.7, pp. 3792-3797, (2004) https://doi.org/10.1063/1.1652243
  10. X. Han, Z. Zeng, W. Li, S. Islam, J. Lu, V. Loggins, L. D. Favro, G. M. Newaz and R. L. Thomas, 'Importance of acoustic chaos in sonic IR imaging NDE,' Review of Quantitative Nondestructive Evaluation, Vol. 23. pp. 496-500 (2004)
  11. X. Han, Md. Sawar Islam, L. D. Favro, G. M. Newaz and R. L. Thomas, 'Simulation of sonic IR imaging of cracks in metals with finite element models,' Review of Quantitative Nondestructive Evaluation, Vol. 25. pp. 544-549, (2006)
  12. M. Morbidini, P. Cawley, T. J. Barden, D. P. Almondi and P. Duffour, 'A new approach for the prediction of the thermosonic signal from vibration records,' Review of Quantitative Nondestructive Evaluation, Vol. 25. pp. 558-565, (2006)