Slope-contour fringe multiplication by Fresnel diffraction - Coherent illumination was used to multiply slope-contour fringes by Fresnel diffraction

Theocaris, PS

dc.contributor.author	Theocaris, PS	en
dc.date.accessioned	2014-03-01T01:37:42Z
dc.date.available	2014-03-01T01:37:42Z
dc.date.issued	1970	en
dc.identifier.issn	00144851	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/21647
dc.subject.other	EXMCA	en
dc.subject.other	MATERIALS TESTING	en
dc.subject.other	MEASUREMENT	en
dc.subject.other	MOIRE	en
dc.subject.other	OPTICS	en
dc.subject.other	STRESSES	en
dc.title	Slope-contour fringe multiplication by Fresnel diffraction - Coherent illumination was used to multiply slope-contour fringes by Fresnel diffraction	en
heal.type	journalArticle	en
heal.identifier.primary	10.1007/BF02320420	en
heal.identifier.secondary	http://dx.doi.org/10.1007/BF02320420	en
heal.publicationDate	1970	en
heal.abstract	Coherent collimated monochromatic light emitted from a He-Ne laser was used to illuminate a transparent sheet specimen in plane stress. The light emerging from the specimen was concentrated by a thin positive lens on a coarse amplitude grating placed at the vicinity of the focus of the lens and projected on a ground-glass screen. The strongly coherent light of the laser was diffracted at the coarse grating. The deformed lateral surfaces of the loaded specimen worked as a thin lens of continuously variable focal length, which was interposed in the path of the beam and distorted the diffraction image. The pattern yielded the partialslope contours of the thickness variation in a direction normal to the rulings of the grating. Positioning the grating within the focal distance of the lens resulted in a predominant Fresnel diffraction of the opaque strips of the grating. Placing the grating beyond the focal plane created a Fresnel diffraction of the open slits. Both diffraction patterns yielded a high multiplication of fringes which increased considerably the accuracy of the experimental results. © 1970 Society for Experimental Mechanics, Inc.	en
heal.journalName	Experimental Mechanics	en
dc.identifier.doi	10.1007/BF02320420	en
dc.identifier.volume	10	en
dc.identifier.issue	9	en
dc.identifier.spage	377	en
dc.identifier.epage	383	en