Application of pulsed reflection holography to materal testing
article
When holography is applied outside the laboratory, problems are encountered such as vibrations, rigid-body motion, and stray daylight. Pulsed holography can overcome the difficulties with vibrations, but the other problems are less easily solved. When the object area to be holographically tested is small, a simple and convenient method may be employed, which was described independently by Boone (1974) and Neumann and Penn (1975). They fixed the hologram holder rigidly to the object under test, thus avoiding rigid-body motion of the object with respect to the hologram. In a similar configuration Denisyuk reflection holograms are made without darkening the environment. The authors believe that the main reason this technique is not widely used is due to difficulties in processing the Denisyuk hologram to good quality. This paper describes a simple technique that results in high quality reflection holograms that may be analyzed by microscope up to interference fringe densities of about 30 fringes/mm. As examples, the results of a projectile impact study and of early fatigue crack detection in a critical airplane structure are presented.
Topics
TNO Identifier
229873
ISSN
00913286
Source
Optical Engineering, 24(6), pp. 1086-1092.
Pages
1086-1092
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