Abstract
A method has been developed for the generation of isopachic fringes in photoelastic coatings. This method requires that the front (outer) surface of the coating be deposited with a thin metallic film to increase the front-surface reflellctivity. The light which penetrotes the photoelastic coating reflects from the rear surface, emerges from the front surface and then combines with the frontsurface reflection to yield a system of “carrier” fringes. When the model is loaded, the carrier-fringer system is modulated by the principal-strain sums and the principalstrain differences. Superposition of the modulate carrierfringer system with the original one (by double exposure or by superposition) yields isopachic and isochromatic fringes. The isochromatics can be suppressed by proper selection of the photoelastic material to yield only isopachics for the unambiguous determination of principal-strain sums over the full field.
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Hovanesian, J.D., Eggenberger, G. & Hung, Y.Y. Full-field isopachic generation in photoelastic coatings. Experimental Mechanics 12, 196–200 (1972). https://doi.org/10.1007/BF02330273
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DOI: https://doi.org/10.1007/BF02330273