Application of Denisyuk pulsed holography to material testing
conference paper
When holography is applied outside the laboratory, some well known problems are experienced: vibrations, rigid body motion, stray daylight. Pulse 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 very simple and convenient method may be employed, which was earlier described by Neumann and Penn; they fixed the hologram holder rigidly on 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 any necessity of darkening the environment. The authors believe that the main reason that this technique is not widely used, is due to difficulties generally encountered in processing the Denisyuk hologram to good guality. A simple processing technigue is described resulting in high guality reflection holograms which may be analysed by microscope up to interference fringe densities of about 30 fringes/mm. As examples the results of a projectile impact study and the study of early fatigue crack detection in a critical aeroplane structure will be presented.
Topics
TNO Identifier
246560
Publisher
SPIE
Source title
Proceedings of SPIE conference on Industrial Applications of Laser Technology, 19-22 April, 1983, Geneva, Switzerland
Collation
12 p.
Place of publication
Bellingham
Pages
138-148