Investigation of Holographic Testing Techniques.
Semiannual technical rept. 27 Nov 68-31 May 69,
MICHIGAN UNIV ANN ARBOR INST OF SCIENCE AND TECHNOLOGY
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This is a technical report of the application of holography to nondestructive testing. It includes studies of interferometric crack detection and transparent-model study, pulsed-laser interferometry and contouring, ultrasonic holography, and modulated reference-beam holography. Holographic interferometry has been used to detect microcracks in high-strength steel structures. The results of the holographic tests have been compared with the results of conventional crack-detection tests. Preliminary experiments dealing with holographic interferometry and photoelasticity of three-dimensional transparent objects under mechanical load have been conducted. An analysis of fringe formation has been made. Investigations into the application of pulsed-laser holographic interferometry and contouring to non-destructive testing has been initiated. Work to date has dealt with the development of the pulsed-laser system itself. Exploratory investigations of synthetic-aperture ultrasonic imaging have been carried out. Analysis and experimentation dealing with modulated reference-beam holography have been conducted. It is hoped that this may be of use in testing associated with periodically loaded materials. An investigation into the application of hologram interferometry to flaw detection has been initiated, which includes an analysis of fringe location and its manipulation. Experimental work has shown the feasibility of using hologram interferometry to detect various types of flaws in cylindrical steel objects. Author
- Lasers and Masers
- Test Facilities, Equipment and Methods