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A model for the ultrasonic detection of surface-breaking cracks by the scanning laser-source technique

Arias, Irene and Achenbach, Jan D. (2004) A model for the ultrasonic detection of surface-breaking cracks by the scanning laser-source technique. In: Nondestructive Evaluation and Health Monitoring of Aerospace Materials and Composites III. Proceedings of SPIE. No.5393. Society of Photo-optical Instrumentation Engineers (SPIE) , Bellingham, WA, pp. 123-131. ISBN 9780819453105. http://resolver.caltech.edu/CaltechAUTHORS:20180725-105501299

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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.


Item Type:Book Section
Related URLs:
URLURL TypeDescription
https://doi.org/10.1117/12.540109DOIArticle
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.
Group:GALCIT
Funders:
Funding AgencyGrant Number
Federal Aviation Administration (FAA)DFTA 03-98-D-0008
Subject Keywords:Laser ultrasonics, thermoelastic regime, line-source, surface-breaking crack, modelling, Scanning Laser Source technique
Record Number:CaltechAUTHORS:20180725-105501299
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20180725-105501299
Official Citation:Irene Arias, Jan D. Achenbach, "A model for the ultrasonic detection of surface-breaking cracks by the scanning laser-source technique", Proc. SPIE 5393, Nondestructive Evaluation and Health Monitoring of Aerospace Materials and Composites III, (20 July 2004); doi: 10.1117/12.540109; https://doi.org/10.1117/12.540109
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:88248
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:25 Jul 2018 18:05
Last Modified:25 Jul 2018 18:05

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