Radial gratings as moiré gauges

Theocaris, PS

dc.contributor.author	Theocaris, PS	en
dc.date.accessioned	2014-03-01T01:37:41Z
dc.date.available	2014-03-01T01:37:41Z
dc.date.issued	1968	en
dc.identifier.issn	00223735	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/21628
dc.title	Radial gratings as moiré gauges	en
heal.type	journalArticle	en
heal.identifier.primary	10.1088/0022-3735/1/6/307	en
heal.identifier.secondary	http://dx.doi.org/10.1088/0022-3735/1/6/307	en
heal.identifier.secondary	307	en
heal.publicationDate	1968	en
heal.abstract	A theory on the formation of moiré patterns by mutually interfering radial gratings is developed. It is shown that the moiré fringes formed inside the circle, which has as diameter the centre-to-centre distance of the gratings, belong to the additive moiré type and they represent families of confocal equilateral hyperbolae. Outside this circle the subtractive moiré pattern is valid, which consists of circles of different radii whose centres lie on the perpendicular bisector of the centre-to-centre distance. For the radial grating moiré gauge the additive moiré pattern is of importance since two sectors of radial gratings are used with a large centre-to-centre distance. The radial gauge is convenient for determining the normal components of strains. The advantage of this type of gauge over the line grating gauge is that the radial grating corresponds to an infinite number of line gratings of progressively varying pitch. This allows a correct evaluation of displacement and strain at a suitably selected gauge length.	en
heal.journalName	Journal of Physics E: Scientific Instruments	en
dc.identifier.doi	10.1088/0022-3735/1/6/307	en
dc.identifier.volume	1	en
dc.identifier.issue	6	en
dc.identifier.spage	613	en
dc.identifier.epage	618	en