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Scaling Effects on Damage Development, Strength, and Stress-Rupture Life on Laminated Composites in Tension

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dc.contributor.authorLavoie, J. Andréen
dc.contributor.committeechairMorton, Johnen
dc.contributor.committeecochairCurtin, William A. Jr.en
dc.contributor.committeememberCramer, Mark S.en
dc.contributor.committeememberJackson, Karen E.en
dc.contributor.committeememberReifsnider, Kenneth L.en
dc.contributor.committeememberMorris, Don H.en
dc.contributor.departmentEngineering Science and Mechanicsen
dc.date.accessioned2014-03-14T20:21:55Zen
dc.date.adate1997-04-04en
dc.date.available2014-03-14T20:21:55Zen
dc.date.issued1997-04-04en
dc.date.rdate1997-04-04en
dc.date.sdate1998-07-18en
dc.description.abstractThe damage development and strength of ply-level scaled carbon/epoxy composite laminates having stacking sequence of [+Tn/-Tn/902n]s where constraint ply angle, T, was 0, 15, 30, 45, 60, and 75 degrees, and size was scaled as n=1,2,3, and 4, is reported in Part I. X-radiography was used to monitor damage developments. First-ply failure stress, and tensile strength were recorded. First-ply failure of the midplane 90 deg. plies depended on the stiffness of constraint plies, and size. All 24 cases were predicted using Zhang's shear-lag model and data generated from cross-ply tests. Laminate strength was controlled by the initiation of a triangular-shaped local delamination of the surface angle plies. This delamination was predicted using O'Brien's strain energy release rate model for delamination of surface angle plies. For each ply angle, the smallest laminate was used to predict delamination (and strength) of the other sizes. The in-situ tensile strength of the 0 deg. plies within different cross-ply, and quasi-isotropic laminates of varying size and stacking sequence is reported in Part II. No size effect was observed in the strength of 0 deg. plies for those lay-ups having failure confined to the gauge section. Laminates exhibiting a size-strength relationship, had grip region failures for the larger sizes. A statistically significant set of 3-point bend tests of unidirectional beams were used to provide parameters for a Weibull model, to re-examine relationship between ultimate strength of 0 deg. plies and specimen volume. The maximum stress in the 0 deg. plies in bending, and the tensile strength of the 0 deg. plies (from valid tests only) was the same. Weibull theory predicted loss of strength which was not observed in the experiments. An effort to model the durability and life of quasi-isotropic E-glass/913 epoxy composite laminates under steady load and in an acidic environment is reported in Part III. Stress-rupture tests of unidirectional coupons immersed in a weak hydrochloric acid solution was conducted to determine their stress-life response. Creep tests were conducted on unidirectional coupons parallel and transverse to the fibers, and on ±45°. layups to characterize the lamina stress- and time-dependent compliances. These data were used in a composite stress-rupture life model, based on the critical element modeling philosophy of Reifsnider, to predict the life of two ply-level thickness-scaled quasi-isotropic laminates.en
dc.description.degreePh. D.en
dc.format.extentx, 145 leavesen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-4131162939721181en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-4131162939721181/en
dc.identifier.urihttp://hdl.handle.net/10919/30510en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartetd-part1.pdfen
dc.relation.haspartetd-part2.pdfen
dc.relation.haspartetd-part3.pdfen
dc.relation.haspartetd_full.pdfen
dc.relation.isformatofOCLC# 38726086en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectstress-corrosion crackingen
dc.subjectstress relaxationen
dc.subjectstrength scalingen
dc.subjectsize effectsen
dc.subjectmicrocrackingen
dc.subjectfirst-ply failureen
dc.subjectdelaminationen
dc.subjectcomposite materialen
dc.subjectweibull statisticsen
dc.subjecttension testingen
dc.subjectflexural testingen
dc.subjectcarbon/epoxyen
dc.subjectglass/epoxyen
dc.subjectcreepen
dc.subjectstress0cuptureen
dc.subjectcreep-ruptureen
dc.subjectdurabiltyen
dc.subjectlifeen
dc.subject.lccLD5655.V856 1997.L386en
dc.titleScaling Effects on Damage Development, Strength, and Stress-Rupture Life on Laminated Composites in Tensionen
dc.typeDissertationen
dc.type.dcmitypeTexten
thesis.degree.disciplineEngineering Science and Mechanicsen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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