A model for the ultrasonic detection of surface-breaking cracks by the scanning laser-source technique
- Creators
- Arias, Irene
- Achenbach, Jan D.
- Others:
- Shull, Peter J.
- Gyekenyesi, Andrew L.
Abstract
A model for the Scanning Laser Source (SLS) technique is presented. The SLS is a novel laser based inspection method for the ultrasonic detection of small surface-breaking cracks. The generated ultrasonic signal is monitored as a line-focused laser is scanned over the defect. Characteristic changes in the amplitude and the frequency content are observed. The modelling approach is based on the decomposition of the field generated by the laser in a cracked two-dimensional half-space, by virtue of linear superposition, into the incident and the scattered fields. The incident field is that generated by laser illumination of a defect-free half-space. A thermoelastic model has been used which takes account of the effect of thermal diffusion, as well as the finite width and duration of the laser source. The scattered field incorporates the interactions of the incident field with the surface-breaking crack. It has been analyzed numerically by a direct frequency domain boundary element method. A comparison with an experiment for a large defect shows that the model captures the observed phenomena.
Additional Information
© 2004 Society of Photo-optical Instrumentation Engineers (SPIE). This work was carried out in the course of research funded by the Federal Aviation Administration under Contract #DFTA 03-98-D-0008 through the Air Transportation Center of Excellence in Airworthiness Assurance.Attached Files
Published - 123.pdf
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Additional details
- Eprint ID
- 88248
- Resolver ID
- CaltechAUTHORS:20180725-105501299
- Federal Aviation Administration (FAA)
- DFTA 03-98-D-0008
- Created
-
2018-07-25Created from EPrint's datestamp field
- Updated
-
2021-11-16Created from EPrint's last_modified field
- Caltech groups
- GALCIT
- Series Name
- Proceedings of SPIE
- Series Volume or Issue Number
- 5393