Dynamic measurement and characterization of Poisson's ratio

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dc.contributor.authorLomenzo, Richard A. Jr.en
dc.contributor.committeechairCudney, Harley H.en
dc.contributor.committeememberWicks, Alfred L.en
dc.contributor.committeememberRobertshaw, Harry H.en
dc.contributor.departmentMechanical Engineeringen
dc.date.accessioned2014-03-14T21:37:24Zen
dc.date.adate2009-06-10en
dc.date.available2014-03-14T21:37:24Zen
dc.date.issued1994-04-05en
dc.date.rdate2009-06-10en
dc.date.sdate2009-06-10en
dc.description.abstractPoisson's ratio for aluminum is estimated from velocity profile measurements of a free-free beam under dynamic loading conditions A weighted least-squares method is used to select a beam model which is subsequently used to determine the transverse and anticlastic radii of curvature. The model of the beam velocity profile is selected using forward regression with the possible regressor set formed by products of Legendre polynomials in x and y, the two-dimensional coordinates of the beam. The resulting model is manipulated to extract the transverse and anticlastic radii of curvature of the beam which are then used to find local and global estimates of Poisson's ratio. Estimates for Poisson's ratio are found for three different forcing frequencies and three force amplitudes at each frequency. The frequencies selected correspond to the frequencies of the operating shapes dominated by the first, second, and third bending modes. A statistical analysis is performed to assess the quality of the estimates of Poisson's ratio. Results show that the estimates of Poisson fs ratio are dependent on the forcing frequency and forcing amplitude. All estimates are below the accepted value of .33 for aluminum. Contributions of plate modes adversely affect the estimates. Estimates based on the first and third operating shapes exhibit a lower variance than the estimate based on the second operating shapes.en
dc.description.degreeMaster of Scienceen
dc.format.extentxv, 129 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-06102009-063143en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-06102009-063143/en
dc.identifier.urihttp://hdl.handle.net/10919/42988en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V855_1994.L664.pdfen
dc.relation.isformatofOCLC# 30830605en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V855 1994.L664en
dc.subject.lcshAluminum -- Testingen
dc.subject.lcshMaterials -- Dynamic testingen
dc.subject.lcshPoisson processesen
dc.titleDynamic measurement and characterization of Poisson's ratioen
dc.typeThesisen
dc.type.dcmitypeTexten
thesis.degree.disciplineMechanical Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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