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.
Original language | English |
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Article number | 035701 |
Number of pages | 14 |
Journal | Measurement Science and Technology |
Volume | 22 |
Issue number | 3 |
Early online date | 1 Feb 2011 |
DOIs | |
Publication status | Published - Mar 2011 |
Keywords
- cracks
- nondestructive evaluation
- laser
- thermography