Stress analysis combining speckle metrology with finite element modelling.

The work described in this report represents a successful demonstration of a hybrid approach to the analysis of structural deformation. Mathematical modelling was incorporated into the process of reducing data from a digital correlation analysis of experimentally obtained speckle data. This experimental data was collected by both directly imaging the speckled surface of the test subject onto a vidicon camera/digitizer system and by transmitting this image to the camera via a flexible coherent fiber optic image bundle. Considerable savings of time and resources can be realized through applications of this hybrid approach in which the strengths of the theoretical and experimental procedures complement each other beautifully. The final hybrid results compare very favorable with values obtained by both a theoretical mathematical (finite element) analysis and an independent experimental (high frequency Moire) study, demonstrating the accuracy and realiability of this hybrid procedure. Finally, the successful use of flexible optical fiber elements for data access demonstrates the potential for application of speckle hybrid techniques to the study of remote or otherwise inaccessible regions of a prototype structure.