Laser beam detection of ultrasonic and acoustic emission signals for nondestructive testing of materials
Abstract
The optical detection systems for measuring ultrasonic and acoustic emission waves inside transparent solids and absolute displacements caused by these waves on the surfaces of opaque solids are described. Using stabilized or differential interferometric probes absolute surface displacements due to ultrasonic waves are observed. Bulk-transducer-generated ultrasonic waves and acoustic emission signals are observed with a narrow beam probe, and the ultrasonic field pattern is scanned with a Doppler-shift scattering probe in transparent solids. Advantages realized by the systems are discussed and it is concluded that optical probing improves ultrasonic transducer calibration and permits direct and accurate waveform and frequency characterization of acoustic emission sources. Optical probing is presently the only viable technique for the remote sensing of ultrasound signals in inaccessible locations or hazardous environments.
- Publication:
-
In: Applications of lasers in materials processing; Proceedings of the Conference
- Pub Date:
- 1979
- Bibcode:
- 1979aplm.proc..161G
- Keywords:
-
- Acoustic Emission;
- Differential Interferometry;
- Laser Applications;
- Nondestructive Tests;
- Ultrasonic Flaw Detection;
- Diffraction Propagation;
- Doppler Effect;
- Light Beams;
- Light Scattering Meters;
- Michelson Interferometers;
- Piezoelectric Transducers;
- Stress Corrosion Cracking;
- Instrumentation and Photography