Using optical methods for strain determination on a curved surface is not simple, because many factors, syeh as directions of viewing, recording, and surface normal, have to be corrected, it is even more difficult when one wishes to have information on the entire 380° surface. In this paper, we propose a method which essentially eliminates all these problems. The technique employs a cylindrical ground glass illuminated with laser light from ail circumferential directions with proper optics resulting in the generation of a unique spatial speckle field in the interior space of the ground glass. A cylindrical specimen coated with photosensitive material on its outer surface is inserted into this speckle field. Exposures are made before and after the application of load.

© 1983 Optical Society of America

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