A viscoelastic macro-microfracture delay mechanism approach in particulate epoxy composites

Kytopoulos, VN

dc.contributor.author	Kytopoulos, VN	en
dc.date.accessioned	2014-03-01T01:19:51Z
dc.date.available	2014-03-01T01:19:51Z
dc.date.issued	2004	en
dc.identifier.issn	0731-6844	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/15728
dc.relation.uri	http://www.scopus.com/inward/record.url?eid=2-s2.0-4344668646&partnerID=40&md5=fdef845e229d062669be95b2bac73440	en
dc.subject	Crack growth	en
dc.subject	Evolution time	en
dc.subject	Fracture delay	en
dc.subject	Microcrack	en
dc.subject	Relaxation time	en
dc.subject	Viscoelastic effects	en
dc.subject.classification	Materials Science, Composites	en
dc.subject.classification	Polymer Science	en
dc.subject.other	Computer simulation	en
dc.subject.other	Crack propagation	en
dc.subject.other	Epoxy resins	en
dc.subject.other	Fracture mechanics	en
dc.subject.other	Microcracks	en
dc.subject.other	Plates (structural components)	en
dc.subject.other	Scanning electron microscopy	en
dc.subject.other	Viscoelasticity	en
dc.subject.other	Evolution time	en
dc.subject.other	Fracture delay	en
dc.subject.other	Relaxation time	en
dc.subject.other	Thermal blunting effect	en
dc.subject.other	Viscoelastic effects	en
dc.subject.other	Composite materials	en
dc.title	A viscoelastic macro-microfracture delay mechanism approach in particulate epoxy composites	en
heal.type	journalArticle	en
heal.language	English	en
heal.publicationDate	2004	en
heal.abstract	By adopting a theoretical model of the elastic-plastic Fracture Mechanics as a reference one concerning the viscoelastic crack growth in cracked plates and by relating this model with a certain viscoelastic as well as macro-microfailure parametric transitional approach, seems to be possible to "gross simulate" the real crack growth behavior in a polymeric composite system by means of the adopted model. This possibility is based on the relative good "general viscoelastic response" of the reference model to the material and experimental conditions. This "viscoelastic response" in turn is consistent with the proposed fracture delay mechanism which is deduced by means of a semiquantitative gross estimation approach methodology. In this methodology the basic assumption that the main contribution to the proposed fracture delay mechanism is given by viscoelastic loss effects and less by the plastic flow and/or adiabatic thermal blunting effects localized at the propagating crack tip seems to be consistent with the material and experimental conditions. In this context it can. be reasonably assumed that this delay mechanism in fact may consist of two consecutive phases. The first one which gives the microcrack growth is controlled by short-range intramolecular rearrangements which in turn are expressed by local (crack tip) characteristic relaxation time. The second one which gives the macrocrack growth is controlled by longrange intermolecular rearrangements which in turn are expressed by a characteristic "bulk" relaxation time. The experimental evidence and modeling of these phases was assisted by in situ scanning electron microscopy (SEM) tensile observations and related measurements. Related to these observations was the statement that the proposed delay mechanism is enhancing assisted by the microvoid-microcrack coalescence "submechanism" ahead of the crack tip (notch root). As a result of all the above, an operational mode for the experimental fracture delay characterization of the polymeric composite system by means of a nomogram-aided evaluation technique is introduced.	en
heal.publisher	SAGE PUBLICATIONS LTD	en
heal.journalName	Journal of Reinforced Plastics and Composites	en
dc.identifier.isi	ISI:000223323900009	en
dc.identifier.volume	23	en
dc.identifier.issue	12	en
dc.identifier.spage	1325	en
dc.identifier.epage	1349	en