Laser generated ultrasound: efficiency and damage thresholds in carbon fibre reinforced composites
UNSPECIFIED. (2001) Laser generated ultrasound: efficiency and damage thresholds in carbon fibre reinforced composites. IEE PROCEEDINGS-SCIENCE MEASUREMENT AND TECHNOLOGY, 148 (4). pp. 139-142. ISSN 1350-2344Full text not available from this repository.
Laser techniques are beginning to be used for non-contact ultrasonic inspection of carbon fibre reinforced composites in industry. The ultrasound is normally generated with a high-power pulsed laser and is detected with a laser interferometer. Other non-contact detection methods can also be used, such as simpler laser beam deflection techniques and air coupled transducers. The authors compare the generation efficiency and damage thresholds of a fundamental Nd:YAG laser (1.06 mum), and a TEA CO, laser (10.6 mum) which is normally preferred for carbon-fibre reinforced composites). A Nd:YAG laser with an optical parametric oscillator (OPO) tunable up to 4 mum is also examined. The laser energy is absorbed within the optical absorption depth; the temperature rise is affected by the wavelength and laser pulse duration. It is essential to remain in the thermoelastic regime in order not to damage the material. A modified Michelson interferometer is used to detect the absolute displacement of the ultrasound. Optical beam deflection techniques and air-coupled transducers are also evaluated as detectors.
|Item Type:||Journal Article|
|Subjects:||T Technology > TK Electrical engineering. Electronics Nuclear engineering|
|Journal or Publication Title:||IEE PROCEEDINGS-SCIENCE MEASUREMENT AND TECHNOLOGY|
|Publisher:||IEE-INST ELEC ENG|
|Official Date:||July 2001|
|Number of Pages:||4|
|Page Range:||pp. 139-142|
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