Crack imaging by scanning laser-line thermography and laser-spot thermography

T Li, Darryl P Almond, D Andrew S Rees

Research output: Contribution to journalArticle

  • 45 Citations

Abstract

The thermographic images of laser-heated spots or lines are perturbed by nearby cracks, providing NDE techniques for crack detection. Scanning with a laser line, rather than a laser spot, results in a substantial reduction in inspection time. 3D finite difference modelling results are presented that show the sensitivity of the laser-line thermography technique to cracks of varying lengths, depths and openings. A novel crack imaging technique is presented that is based on assembling the second spatial derivative thermal images of a scanned laser line. Experimental results show the new technique to image cracks with openings as small as a few micrometres. The scanning time of the laser-line thermography technique is shown to be over an order of magnitude smaller than that of the laser-spot thermography technique whilst producing crack images of similar quality.
LanguageEnglish
Article number035701
Number of pages14
JournalMeasurement Science and Technology
Volume22
Issue number3
Early online date1 Feb 2011
DOIs
StatusPublished - Mar 2011

Fingerprint

Laser Scanning
Crack
cracks
Imaging
Laser
Cracks
Scanning
Imaging techniques
scanning
Lasers
Line
lasers
Crack Detection
Crack detection
assembling
imaging techniques
Inspection
micrometers
inspection
Finite Difference

Keywords

  • cracks
  • nondestructive evaluation
  • laser
  • thermography

Cite this

Crack imaging by scanning laser-line thermography and laser-spot thermography. / Li, T; Almond, Darryl P; Rees, D Andrew S.

In: Measurement Science and Technology, Vol. 22, No. 3, 035701, 03.2011.

Research output: Contribution to journalArticle

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