Exploratory Nondestructive Evaluation (NDE) Research for Advanced Materials and Processes. Volume 2: Shearography Improvements

Abstract : Shearography Improvements: Shearographic inspection of aerospace structures has not gained wide acceptance, owing to the difficulty of interpreting shearographic images. A feature extraction method was developed that calculates surface normal curvature from input shearograms. The method can be applied in real time to provide a technician unambiguous images representing areas of locally high curvature, which will generally highlight the boundaries of flaws. Images are load independent and insensitive to part viewing angle. Analytical and experimental validation tests were completed for vacuum, vibrational and thermal loading. Recommendations are presented for system development, and for practical implementation of shearography.