Non-contact ultrasound studies of composite materials: new developments
UNSPECIFIED (2000) Non-contact ultrasound studies of composite materials: new developments. In: Conference on Nondestructive Evaluation of Aging Materials and Composites IV, MAR 08-09, 2000, NEWPORT BEACH, CA.Full text not available from this repository.
Techniques are being developed worldwide for non-contact ultrasonic inspection of composite materials. These include laser generation and optical detection of ultrasound; both with interferometers and simpler beam deflection techniques, air coupled transducers are also used as generators and/or detectors of ultrasound. This paper compares the generation efficiency and damage thresholds of a range of different laser types: A fundamental Nd:YAG laser (1.06 mu m), a TEA CO2 laser (10.6 mu m normally preferred for carbon-fibre reinforced composites) and a Nd:YAG laser with an Optical Parametric Oscillator (OPO) tunable up to 4 mu m. The laser energy is absorbed with 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:||Conference Item (UNSPECIFIED)|
|Subjects:||Q Science > QC Physics|
|Series Name:||PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE)|
|Journal or Publication Title:||NONDESTRUCTIVE EVALUATION OF AGING MATERIALS AND COMPOSITES IV|
|Publisher:||SPIE-INT SOC OPTICAL ENGINEERING|
|Editor:||Baaklini, GY and Lebowitz, CA and Boltz, ES|
|Number of Pages:||8|
|Page Range:||pp. 268-275|
|Title of Event:||Conference on Nondestructive Evaluation of Aging Materials and Composites IV|
|Location of Event:||NEWPORT BEACH, CA|
|Date(s) of Event:||MAR 08-09, 2000|
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