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dc.contributor.authorHayes, Michael Daviden_US
dc.date.accessioned2011-08-22T18:51:22Z
dc.date.available2011-08-22T18:51:22Z
dc.date.issued2003-11-18en_US
dc.identifier.otheretd-12052003-154555en_US
dc.identifier.urihttp://hdl.handle.net/10919/11066
dc.description.abstractThis dissertation is focused on understanding the performance of a particular fiber-reinforced polymeric composite structural beam, a 91.4 cm (36 inch) deep pultruded double-web beam (DWB) designed for bridge construction. Part 1 focuses on calculating the Timoshenko shear stiffness of the DWB and understanding what factors may introduce error in the experimental measurement of the quantity for this and other sections. Laminated beam theory and finite element analysis (FEA) were used to estimate the shear stiffness. Several references in the literature have hypothesized an increase in the effective measured shear stiffness due to warping. A third order laminated beam theory (TLBT) was derived to explore this concept, and the warping effect was found to be negligible. Furthermore, FEA results actually indicate a decrease in the effective shear stiffness at shorter spans for simple boundary conditions. This effect was attributed to transverse compression at the load points and supports. The higher order sandwich theory of Frostig shows promise for estimating the compression related error in the shear stiffness for thin-walled beams. Part 2 attempts to identify the failure mechanism(s) under quasi-static loading and to develop a strength prediction for the DWB. FEA was utilized to investigate two possible failure modes in the top flange: compression failure of the carbon fiber plies and delamination at the free edges or taper regions. The onset of delamination was predicted using a strength-based approach, and the stress analysis was accomplished using a successive sub-modeling approach in ANSYS. The results of the delamination analyses were inconclusive, but the predicted strengths based on the compression failure mode show excellent agreement with the experimental data. A fatigue life prediction, assuming compression failure, was also developed using the remaining strength and critical element concepts of Reifsnider et al. One DWB fatigued at about 30% of the ultimate capacity showed no signs of damage after 4.9 million cycles, although the predicted number of cycles to failure was 4.4 million. A test on a second beam at about 60% of the ultimate capacity was incomplete at the time of publication. Thus, the success of the fatigue life prediction was not confirmed.en_US
dc.format.mediumETDen_US
dc.publisherVirginia Techen_US
dc.relation.haspartHayes_Appendix_A_TLBT.pdfen_US
dc.relation.haspartHayes_Part_1_shear_stiffness.pdfen_US
dc.relation.haspartHayes_Appendix_B_ANSYS_code.pdfen_US
dc.relation.haspartHayes_Part_2_strength_and_life_predictions.pdfen_US
dc.rightsThis Item is protected by copyright and/or related rights. Some uses of this Item may be deemed fair and permitted by law even without permission from the rights holder(s), or the rights holder(s) may have licensed the work for use under certain conditions. For other uses you need to obtain permission from the rights holder(s).en_US
dc.subjectfinite element analysisen_US
dc.subjectbeam theoryen_US
dc.subjectfatigue lifeen_US
dc.subjectremaining strengthen_US
dc.subjectstrengthen_US
dc.subjectdurabilityen_US
dc.subjectFRP beamen_US
dc.subjectcompressionen_US
dc.subjectdelaminationen_US
dc.subjectTimoshenko shear stiffnessen_US
dc.titleStructural Analysis of a Pultruded Composite Beam: Shear Stiffness Determination and Strength and Fatigue Life Predictionsen_US
dc.typeDissertationen_US
dc.contributor.departmentEngineering Science and Mechanicsen_US
dc.description.degreePhDen_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
dc.contributor.committeechairLesko, John J.en_US
dc.contributor.committeememberCase, Scott W.en_US
dc.contributor.committeememberHyer, Michael W.en_US
dc.contributor.committeememberHajj, Muhammad R.en_US
dc.contributor.committeememberCousins, Thomas E.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-12052003-154555en_US
dc.date.sdate2003-12-05en_US
dc.date.rdate2003-12-08
dc.date.adate2003-12-08en_US


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