Nondestructive Holographic Techniques for Structures Inspection.

The program is an investigation of the feasibility of using holographic interferometry for the inspection of large aircraft structures in a manufacturing or maintenance environment. The second year's work comprised the following: An investigation of the effects of airborne particulates on the holographic process, a study of holographic methods suitable for the manufacturing or maintenance environment, an investigation and experimental demonstration of two new moire methods for the visualization of strain patterns, investigations of potential stress generating mechanisms, suitable for the holographic detection of cracks, in which it was experimentally demonstrated that surface waves can be generated and attenuated by cracks, and experimental demonstrations that illustrated the potential of holography, in combination with ultrasonic excitation, for solving cooling passage alignment inspection problems. (Modified author abstract)