A SEM-fractographic study of dynamic crack propagation effects in particulate epoxy systems under impact loading conditions

Kytopoulos, VN; Badalouka, BG; Bourkas, GD; Sideridis, E

dc.contributor.author	Kytopoulos, VN	en
dc.contributor.author	Badalouka, BG	en
dc.contributor.author	Bourkas, GD	en
dc.contributor.author	Sideridis, E	en
dc.date.accessioned	2014-03-01T01:29:38Z
dc.date.available	2014-03-01T01:29:38Z
dc.date.issued	2009	en
dc.identifier.issn	0731-6844	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/19331
dc.subject	Crack velocity	en
dc.subject	Defect-induced shift	en
dc.subject	Dissipative effects	en
dc.subject	Fractographic patterns	en
dc.subject	Fracture process time spectrum	en
dc.subject	Kinematic toughness	en
dc.subject	Multiple crack splitting	en
dc.subject	Retardation effects	en
dc.subject	Single crack splitting	en
dc.subject	Surface roughness	en
dc.subject	Viscoelastic effects	en
dc.subject.classification	Materials Science, Composites	en
dc.subject.classification	Polymer Science	en
dc.subject.other	Brittleness	en
dc.subject.other	Crack propagation	en
dc.subject.other	Defects	en
dc.subject.other	Electron energy loss spectroscopy	en
dc.subject.other	Energy dissipation	en
dc.subject.other	Energy dissipators	en
dc.subject.other	Epoxy resins	en
dc.subject.other	Fracture	en
dc.subject.other	Free volume	en
dc.subject.other	Friction	en
dc.subject.other	Hydrogen embrittlement	en
dc.subject.other	Kinematics	en
dc.subject.other	Mechanics	en
dc.subject.other	Metal analysis	en
dc.subject.other	Scanning electron microscopy	en
dc.subject.other	Strain rate	en
dc.subject.other	Surface properties	en
dc.subject.other	Surface roughness	en
dc.subject.other	Velocity	en
dc.subject.other	Crack velocity	en
dc.subject.other	Defect-induced shift	en
dc.subject.other	Dissipative effects	en
dc.subject.other	Fractographic patterns	en
dc.subject.other	Fracture process time spectrum	en
dc.subject.other	Kinematic toughness	en
dc.subject.other	Multiple crack splitting	en
dc.subject.other	Retardation effects	en
dc.subject.other	Single crack splitting	en
dc.subject.other	Viscoelastic effects	en
dc.subject.other	Cracks	en
dc.title	A SEM-fractographic study of dynamic crack propagation effects in particulate epoxy systems under impact loading conditions	en
heal.type	journalArticle	en
heal.identifier.primary	10.1177/0731684408094743	en
heal.identifier.secondary	http://dx.doi.org/10.1177/0731684408094743	en
heal.language	English	en
heal.publicationDate	2009	en
heal.abstract	In this complex study an attempt was made on the one hand to analyze and understand in a systematic way the exact nature of the formation of certain characteristic energy dissipation-induced fractographic features and patterns/markings revealed by scanning electron microscopy (SEM) in particulate epoxy systems under impact (dynamic) loading conditions, and on the other hand to correlate these patterns and features with relevant crack propagation effects. For this scope a combined approach consisting of a qualitative as well as a semiquantitative analysis was employed. In the qualitative analytical approach it was shown that depending on the actual velocity and direction of crack propagation the above observed fractographic entities can be correlated to certain highly localized energy dissipative processes at front-failures as well as to local inertial molecular mass effects. Depending on the changes in the velocity and direction of propagation, the associated effects may be controlled by two basic processes: the single crack front and the multiple crack front splitting. The first process seemed to be governed by a shear toughness-biased system, whereas the second one used a critical strain energy release rate subcracking mechanism. Under certain conditions both processes may be influenced by inertial molecular effects in promoting the formation of relative-smooth fracture surfaces. The increased presence of particles tends to restrict an increase in the surface roughness due to energy dissipation-induced crack retardation effects. The presence of the notch tends to lower the fracture surface roughness compared to notch-free specimens and also to suppress the occurrence of certain elastic as well as viscoelastic-plastic crack delay effects observed in notch-free specimens in function of particle volume fraction. Based on relevant kinematics-aided modeling and impact energy measurements it seems possible to explain, by a gross semi-quantitative approach, the above particles and notch effects. In this context it seems plausible that the existence of a defect-induced fracturing time spectrum of the propagating crack front, in combination with the 'notch-induced shift' behavior of this spectrum, can be valuable for some approximating explanations of the above notch effects and in general the 'kinematics' of the surface roughness formation. © 2009 SAGE Publications.	en
heal.publisher	SAGE PUBLICATIONS LTD	en
heal.journalName	Journal of Reinforced Plastics and Composites	en
dc.identifier.doi	10.1177/0731684408094743	en
dc.identifier.isi	ISI:000262954300008	en
dc.identifier.volume	28	en
dc.identifier.issue	3	en
dc.identifier.spage	353	en
dc.identifier.epage	377	en