The Optical Method of Reflected Caustics Applied for a Plate with a Central Hole: Critical Points and Limitations

Pazis, DN; Agioutantis, Z; Kourkoulis, SK

dc.contributor.author	Pazis, DN	en
dc.contributor.author	Agioutantis, Z	en
dc.contributor.author	Kourkoulis, SK	en
dc.date.accessioned	2014-03-01T01:37:27Z
dc.date.available	2014-03-01T01:37:27Z
dc.date.issued	2011	en
dc.identifier.issn	0039-2103	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/21501
dc.subject	caustics	en
dc.subject	finite element method	en
dc.subject	plate with a central hole	en
dc.subject	poly-methyl-meth-acrylate	en
dc.subject.classification	Materials Science, Characterization & Testing	en
dc.subject.other	caustics	en
dc.subject.other	Critical points	en
dc.subject.other	Experimental setup	en
dc.subject.other	External loads	en
dc.subject.other	Finite Element	en
dc.subject.other	Load cells	en
dc.subject.other	Numerical procedures	en
dc.subject.other	Optical methods	en
dc.subject.other	Optical set-up	en
dc.subject.other	Plastic zones	en
dc.subject.other	plate with a central hole	en
dc.subject.other	Remote stress	en
dc.subject.other	Stress field	en
dc.subject.other	Uniaxial tensions	en
dc.subject.other	Photography	en
dc.subject.other	Finite element method	en
dc.title	The Optical Method of Reflected Caustics Applied for a Plate with a Central Hole: Critical Points and Limitations	en
heal.type	journalArticle	en
heal.identifier.primary	10.1111/j.1475-1305.2009.00714.x	en
heal.identifier.secondary	http://dx.doi.org/10.1111/j.1475-1305.2009.00714.x	en
heal.language	English	en
heal.publicationDate	2011	en
heal.abstract	Some critical points related to the applicability of the optical method of reflected caustics in the case of a plate with a central hole are explored in the present paper. The study is carried out in a combined experimental and numerical procedure: poly-methyl-meth-acrylate plates with a central hole are subjected to uniaxial tension and the diameter of the caustics developed is measured for various load steps from a series of successive photographs with the aid of suitable software. The remote stress is then calculated according to the method of caustics and the results are compared with those of the load cell. In addition, the finite element method is employed for the determination of the stress field and the shape and magnitude of the plastic zones around the hole. Conclusions are drawn concerning the range of the external load for which the results of the method of caustics are valid as a function of the relative dimension of the width of the plate versus the diameter of the hole. In addition, the factors influencing the results of the method are considered and the sensitivity of the results to the even the slightest misalignments of the experimental set-up, to the kind of the optical setup preferred and to the slightest deviation from flatness of the lateral faces of the plate is pointed out. This sensitivity of the method was proved to be responsible for discrepancies between theory and experiment, which sometimes exceed 100%. © 2010 Blackwell Publishing Ltd.	en
heal.publisher	WILEY-BLACKWELL	en
heal.journalName	Strain	en
dc.identifier.doi	10.1111/j.1475-1305.2009.00714.x	en
dc.identifier.isi	ISI:000297840000004	en
dc.identifier.volume	47	en
dc.identifier.issue	6	en
dc.identifier.spage	489	en
dc.identifier.epage	498	en