Random vibrations of bladed-disk assembly under cyclostationary excitation

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dc.contributor.authorOlafsson, Sveinn V.en
dc.contributor.departmentAerospace Engineeringen
dc.date.accessioned2014-03-14T21:38:23Zen
dc.date.adate2010-06-12en
dc.date.available2014-03-14T21:38:23Zen
dc.date.issued1988en
dc.date.rdate2010-06-12en
dc.date.sdate2010-06-12en
dc.description.abstractRandom vibration of a bladed-disk assembly is studied. A stochastic model for the excitation is developed. A unique feature of this model is the statistical periodicity of the blade forces called cyclostationary. A random process is called wide sense eyeclostationary and its statistics are periodic in time. Factors like the turbulent nature of the flow around the blades, the variability in their geometry, and their nonuniform deterioration contribute to the uncertainty in the excitation. In periodic structures, like the bladed-disk assembly, small variation in the blade excitation may lead to high variability in the response. The model developed includes both random and deterministic excitation. A comparison of the responses due to the random and the deterministic part shows the significance of taking into account the variability in the blade forces. Therefore the assumption that the blade forces are all equal, used by all methods for vibration analysis of bladed disk assemblies, may lead to erroneous estimates of their response, reliability and expected life. It is shown that the response is a cyclostationary process. Therefore the cyclostationary property is preserved from the input to the output. Furthermore the frequency of the second moment of the response is equal to two times the frequency of the excitation.en
dc.description.degreeMaster of Scienceen
dc.format.extentxiii, 77 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-06122010-020411en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-06122010-020411/en
dc.identifier.urihttp://hdl.handle.net/10919/43261en
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V855_1988.O423.pdfen
dc.relation.isformatofOCLC# 18616232en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V855 1988.O423en
dc.subject.lcshAircraft gas-turbinesen
dc.subject.lcshAirplanes -- Motors -- Designen
dc.titleRandom vibrations of bladed-disk assembly under cyclostationary excitationen
dc.typeThesisen
dc.type.dcmitypeTexten
thesis.degree.disciplineAerospace Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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