Dynamic caustics and its applications

Papadopoulos, GA

dc.contributor.author	Papadopoulos, GA	en
dc.date.accessioned	2014-03-01T01:07:51Z
dc.date.available	2014-03-01T01:07:51Z
dc.date.issued	1990	en
dc.identifier.issn	0143-8166	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/10213
dc.relation.uri	http://www.scopus.com/inward/record.url?eid=2-s2.0-0025592547&partnerID=40&md5=ab040fa45828bd3530c970d8313f68a6	en
dc.subject.classification	Optics	en
dc.subject.other	Composite Materials	en
dc.subject.other	Rubber	en
dc.subject.other	Concentric Rubber Rings	en
dc.subject.other	Dynamic Caustics	en
dc.subject.other	Notched Composites	en
dc.subject.other	PMMA Round Inclusions	en
dc.subject.other	Press-Fitting Inclusions	en
dc.subject.other	Stress Intensity Factor	en
dc.subject.other	Fracture Mechanics	en
dc.title	Dynamic caustics and its applications	en
heal.type	journalArticle	en
heal.language	English	en
heal.publicationDate	1990	en
heal.abstract	For the study of elastodynamic problems of propagating cracks it is necessary to evaluate the dynamic stress intensity factor KdI which depends on the form of expressions for the stress components existing at the running crack tip at any instant of the propagation of the crack and the corresponding dynamic mechanical and optical properties of the material of the specimen under identical loading conditions. In this paper the distortion of the form of the corresponding reflected caustic from the lateral faces of a dynamically loaded transparent and optically inert specimen containing a transverse crack running under constant velocity was studied on the basis of complex potential elasticity theory and the influence of this form on the value of the dynamic stress intensity factor was given. The method was applied to the study of a propagating Mode I crack in a PMMA specimen under various propagation velocities and the corresponding dynamic stress intensity factor KdI evaluated. Also, crack propagation behaviour of notched composites in dynamic loading modes are reviewed and evaluated. A relatively large data base using metal-epoxy particulates, rubber-toughened poly(methyl methacrylate), and Sandwich plates are given. In all cases, a combination of high-speed photography and the optical method of dynamic caustics has been used. Results on the dynamic crack propagation mode, fracture toughness and crack propagation velocities of several rubber-modified composite models are presented. The composite models studied include specimens with one and/or two 'complex' two-stage inclusions, i.e. PMMA round inclusions surrounded by concentric rubber rings, one and/or press-fifting inclusions without rubber interface, all under dynamic loading. In all cases both qualitative and quantitative results were obtained. Also, results on crack propagation mode, crack propagation velocity, stress intensity factors and on the influence of the sandwich phases on crack propagation mode are presented. © 1990.	en
heal.publisher	ELSEVIER SCI LTD	en
heal.journalName	Optics and Lasers in Engineering	en
dc.identifier.isi	ISI:A1990EE66600003	en
dc.identifier.volume	13	en
dc.identifier.issue	3-4	en
dc.identifier.spage	211	en
dc.identifier.epage	249	en