Abstract
Optical interference moiré methods are analyzed using Fraunhoffer diffraction theory to relate general large surface deformations to the fringes observed. This analysis determines the Almansl strain in the current configuration from the gradients of the fringe number function. The analysis shows the advantages of an experimental scheme that allows the virtual reference grating to be varied. The ability to vary the virtual reference grating results in a larger dynamic range and the ability to maintain a fringe spacing for maximum accuracy. A moiré microscope has been constructed which has this ability. Digital image processing coupled with optical filtering and phase control is used to enhance the accuracy of the fringe measurements. The variable virtual-reference-grating capability is demonstrated by using it to highlight several aspects of the deformation field near a crack tip in a single crystal of iron-silicon.
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References
Foucault, L., Annls. Obs. Paris,5,197 (1859).
Tolenaar, D., Interferentieverschijnselen bij Rasterdruk, Amsterdam Institut voor Grafische Techniek (1945).
Morse, S., Durelli, A.J. andSciammarella, C.A., J. Eng. Mech. Div., Proc. ASCE,86 (EM-4),105–126 (1960).
Theocaris, P., Moiré Fringes in Strain Analysis, Pergamon Press, New York (1969).
Durelli, A.J. andParks, V.J., Moiré Analysis of Strain, Prentice Hall, Englewood Cliffs, NJ (1970).
Parks, V.J., Handbook on Experimental Mechanics, ed. A.S. Kobayashi, Prentice Hall, Englewood Cliffs, NJ, Chapt. 6 (1987).
Chiang, F.P., Manual on Experimental Stress Analysis, ed. J.F. Doyle, SEM, Bethel, CT, Chapt. 7 (1989).
Guild, J., The Interference System of Crossed Diffraction Gratings, Clarendon Press, Oxford (1956).
Post, D., Handbook on Experimental Mechanics, ed. A.S. Kobayashi, Prentice Hall, Englewood Cliffs, NJ, Chapt. 7 (1987).
McKelvie, J., “Experimental Photomechanics: Fundamental Physics and Mathematical Contrivances,” MicroMechanics: Experimental Techniques, Proc. Symp. on Experimental Techniques, ASME 1989 Winter Annual Mtg., AMD-102,ed. W.N. Sharpe, Jr. (1989).
Shield, T.W. and Kim, K.-S., “An Experimental Study of the Plastic Deformation Fields near a Crack Tip in an Iron-Silicon Single Crystal,” submitted to J. Mech. and Phys. of Solids (1990).
Born, M. and Wolf, E., Principles of Optics, 3rd Ed., Pergamon Press (1965).
Shield, T.W., Kim, K.-S. and Nikolic, R., “Moiré Microscope for the Experimental Determination of the In-Plane Displacement Field Near a Crack Tip in a Single Crystal,” MicroMechanics: Experimental Techniques, Proc. Symp. on Experimental Techniques, ASME 1989 Winter Annual Mtg., AMD-102,ed. W.N. Sharpe, Jr. (1989).
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Shield, T.W., Kim, K.S. Diffraction theory of optical interference moiré and a device for production of variable virtual reference gratings: A moiré microscope. Experimental Mechanics 31, 126–134 (1991). https://doi.org/10.1007/BF02327564
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DOI: https://doi.org/10.1007/BF02327564