Inside and outside bounds of validity of the method of caustics in elasticity

Theocaris, PS; Petrou, L

dc.contributor.author	Theocaris, PS	en
dc.contributor.author	Petrou, L	en
dc.date.accessioned	2014-03-01T01:06:36Z
dc.date.available	2014-03-01T01:06:36Z
dc.date.issued	1986	en
dc.identifier.issn	0013-7944	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/9502
dc.subject.classification	Mechanics	en
dc.subject.other	ELASTICITY - Evaluation	en
dc.subject.other	STRESSES - Analysis	en
dc.subject.other	SURFACES - Optical Properties	en
dc.subject.other	REFLECTED CAUSTICS	en
dc.subject.other	SINGULAR STRESS FIELDS	en
dc.subject.other	TRANSVERSE CRACK	en
dc.subject.other	PLATES	en
dc.title	Inside and outside bounds of validity of the method of caustics in elasticity	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/0013-7944(86)90115-3	en
heal.identifier.secondary	http://dx.doi.org/10.1016/0013-7944(86)90115-3	en
heal.language	English	en
heal.publicationDate	1986	en
heal.abstract	The core region around the crack tip is defined as the region which is strongly influenced by the rapid and nonlinear variation of the mechanical and optical properties of the substance. Then this region is not convenient for measurements yielding SIFs. In this paper an extensive experimental study was undertaken to define the limits of the core region at a typical crack tip in order to bound the zone of the accurate evaluation of the SIF. Moreover, for large polar distances from the crack tip the singular elastic solution is becoming progressively erroneous, and therefore it yields progressive deviations from the accurate values of K and increasing errors. The method, which was used to determine the zone for the correct evaluation of SIFs, was the method of reflected caustics. The radii of their initial curves, defining the caustics, were changing from lower to higher values as the polar distance,r, from the tip was increasing, and this could be achieved either by varying the external load of the plate and/or the optical and mechanical parameters of the experimental arrangement and the specimen. The respective SIFs evaluated from the reflected caustics were then changed from lower values to constant ones, and then, for larger values of r, they deviated again progressively to higher values. It is evident that the zone of constant Kdefines the limits of validity of the elastic theory based on the singular term of the stress function. Therefore, the constancy of K yields the criterion for the correct size of the core region. By applying the singular-term elastic solution for the evaluation of caustics and the criterion of constancy of the K the whole region of validity of the method was for the first time defined. Experimental evidence and comparison with theoretical results proved the validity of the method. © 1986.	en
heal.publisher	PERGAMON-ELSEVIER SCIENCE LTD	en
heal.journalName	Engineering Fracture Mechanics	en
dc.identifier.doi	10.1016/0013-7944(86)90115-3	en
dc.identifier.isi	ISI:A1986A353700006	en
dc.identifier.volume	23	en
dc.identifier.issue	4	en
dc.identifier.spage	681	en
dc.identifier.epage	693	en