Abstract
Moiré patterns produced by interference of a series of periodically arranged linear light sources with a line-specimen grating of similar pitch are located at a plane parallel to the sources and the specimen grating and at some distance away from these planes. A transparent or reflecting specimen located at a distance from the specimen grating distorts the image of the multisource projected on the specimen grating due to its surface irregularities and forms a moiré pattern. This pattern yields the partial-slope contours of the topography of the specimen along a direction normal to the lines of the grating. Two such contour patterns taken at mutually perpendicular directions are sufficient to yield the complete topographic picture of the surface.
The method was used for determining gradients of thickness variations in two-dimensional specimens due to lateral contraction. The technique is highly accurate in determining the values of thickness in such cases, since the integration of the slope of thickness variation along any traverse of the specimen is a steady and accurate process.
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References
Theocaris, P. S., “The Moiré Method in Plates,” Proc. Intl. Assn. Shell Struct. Symp., North-Holland Publishing Co. and PWN-Polish Sci. Publ. Warsaw, 877–889 (1964).
Theocaris, P. S., “Moiré Topography of Curved Surfaces,”Experimental Mechanics,7 (7),289–296 (1967).
Ligtenberg, F. K., “The Moiré Method—A New Experimental Method for the Determination of Moments in Small Slab Models,” Proc. SESAXII (2),83–98 (1955).
Dantu, P., “Méthode nouvelle pour la détermination des flexions dans une plaque plane,” Annales des Ponts et Chaussées, (1) (1940) and (2) (1950).
De Josselin de Jong, G., “Refraction Moiré Analysis of Curved Surfaces,”Proc. Symp. Shell Res., North-Holland Publ., Delft, 302–308 (1961).
Duncan, J. P., and Brown, C. J. E., “Slope Contours in Flexed Elastic Plates by Salt-Ikeda Technique,” Proc. First SESA Intern. Congress Exp. Mech., B. E. Rossi, Editor, Pergamon Press Publ., 149–176 (1963).
Theocaris, P. S., andKoutsabessis, A., “Slope Measurement by Means of Moiré Fringes,”Jnl. Sci. Inst.,42 (8),607–610 (1965).
Theocaris, P. S., “Moiré Patterns of Slope Contours in Flexed Plates,” Proc. Second SESA Intern. Congr. on Exp. Mech., B. E. Rossi, Editor, 56–61 (1966) and Experimental Mechanics,6 (4), 212–217 (1966).
Theocaris, P. S., “Flexural Vibrations of Plates by the Moiré Method,”Brit. Jnl. Appl. Phys. 18 (4),513–519 (1967).
Theocaris, P. S., “Moiré Analysis of Cylindrical Surfaces,” Ver. Deut. Ing. Berichte No. 102, VDI Verlag Dusseldorf (Proc. Third Intern. Congr. Exp. Stress Anal., Berlin 1966), 44–55 (1966).
McCurry, R. E., “Multiple Source Moiré Patterns”Jnl. Appl. Phys.,37 (2),467–472 (1966).
Theocaris, P. S., “Moiré Fringes: A Powerful Measuring Device,”Appl. Mech. Revs. 15 (5),333–339 (1962).[See also: Applied Mechanics Surveys, Spartan Books Publ., Washington, D. C., 613–626 (1966)].
Born, A., andWolf, E., “Principles of Optics,”Pergamon Press, London (1964).
Theocaris, P. S., “Diffused Light Interferometry for Measurement of Isopachis,”Jnl. Mech. Phys. Solids,11 (3),181–195 (1963).
Howland, R. C. J., “On the Stresses in the Neighbourhood of a Circular Hole in a Strip under Tension,”Phil. Trans. Roy. Soc., London A, 229, 49–86 (1930).
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Theocaris, P.S., Koutsabessis, A. Surface topography by multisource moiré patterns. Experimental Mechanics 8, 82–87 (1968). https://doi.org/10.1007/BF02326131
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DOI: https://doi.org/10.1007/BF02326131