LI
Laser Interferometry
LI – Laser Interferometry is an established technique for measuring small changes in displacement based on the very small, stable and accurately defined wavelength of light. There are several NDT LI techniques: shearography, electronic speckle pattern interferometry (ESPI) and holographic interferometry. Holographic interferometry is mainly a laboratory-based technique, but the other two have found use in the inspection of composite materials for the detection of surface and sub-surface damage. LI works by comparing two images obtained with the laser for two states of deformation. The two images are compared and produce a fringe pattern, which allows the displacement due to damage to be identified. LI techniques can be applied to a surface with an area of a few square millimetres, as well as being used for large-area inspections.
For more information on LI see:
A M Amaro et al, ‘Damage detection on laminated composite materials using several NDT techniques’, Insight, Vol 54, No 1, January 2012
http://www.ndt.net/article/wcndt00/papers/idn732/idn732.htm
http://www.laserndt.com/technology/shearography.htm
What the hec?! articles are not intended to be the definitive account on the topic or acronym in question. Readers’ comments and contributions are welcomed. Email: ndtnews@bindt.org
For more information on LI see:
A M Amaro et al, ‘Damage detection on laminated composite materials using several NDT techniques’, Insight, Vol 54, No 1, January 2012
http://www.ndt.net/article/wcndt00/papers/idn732/idn732.htm
http://www.laserndt.com/technology/shearography.htm
What the hec?! articles are not intended to be the definitive account on the topic or acronym in question. Readers’ comments and contributions are welcomed. Email: ndtnews@bindt.org
