Journal of the Korean Society for Nondestructive Testing (비파괴검사학회지)

The Korean Society for Nondestructive Testing (한국비파괴검사학회)
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Contour Integral Method for Crack Detection

  • Kim, Woo-Jae (University of the Pacific) ;
  • Kim, No-Nyu (Department of Mechanical Engineering, Korea University of Technology and Education) ;
  • Yang, Seung-Yong (Department of Mechanical Engineering, Korea University of Technology and Education)
  • Received : 2011.10.06
  • Accepted : 2011.12.08
  • Published : 2011.12.30
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Abstract

In this paper, a new approach to detect surface cracks from a noisy thermal image in the infrared thermography is presented using an holomorphic characteristic of temperature field in a thin plate under steady-state thermal condition. The holomorphic function for 2-D heat flow field in the plate was derived from Cauchy Riemann conditions to define a contour integral that varies according to the existence and strength of a singularity in the domain of integration. The contour integral at each point of thermal image eliminated the temperature variation due to heat conduction and suppressed the noise, so that its image emphasized and highlighted the singularity such as crack. This feature of holomorphic function was also investigated numerically using a simple thermal field in the thin plate satisfying the Laplace equation. The simulation results showed that the integral image selected and detected the crack embedded artificially in the plate very well in a noisy environment.

Keywords

References

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