Laser generated ultrasound: efficiency and damage thresholds in carbon fibre reinforced composites

C. Edwards, T. Stratoudaki, S. Dixon, S. Palmer

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

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 (1.06μm), and a TEA CO2 laser (10.6μm) which is normally preferred for carbon-fibre reinforced composites. A Nd:YAG laser with an optical parametric oscillator (OPO) tunable up to 4μm 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.

Original languageEnglish
Pages (from-to)139-142
Number of pages4
JournalIEE Proceedings Science Measurement and Technology
Volume148
Issue number4
DOIs
Publication statusPublished - 30 Jul 2001
Externally publishedYes

    Fingerprint

Keywords

  • noncontact ultrasonic inspection
  • carbon fiber reinforced composites
  • high-power pulsed laser
  • laser interferometer
  • damage thresholds
  • generation efficency
  • optical parametric oscillator (OPO)

Cite this