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dc.contributor.authorPrice, Darryl Brianen_US
dc.date.accessioned2014-03-14T20:40:10Z
dc.date.available2014-03-14T20:40:10Z
dc.date.issued2008-06-03en_US
dc.identifier.otheretd-06172008-195556en_US
dc.identifier.urihttp://hdl.handle.net/10919/33625
dc.description.abstractThe main goal of this study is the use of polynomial chaos expansion (PCE) to analyze the uncertainty in calculating the lateral and longitudinal center of gravity for a vehicle from static load cell measurements. A secondary goal is to use experimental testing as a source of uncertainty and as a method to confirm the results from the PCE simulation. While PCE has often been used as an alternative to Monte Carlo, PCE models have rarely been based on experimental data. The 8-post test rig at the Virginia Institute for Performance Engineering and Research facility at Virginia International Raceway is the experimental test bed used to implement the PCE model. Experimental tests are conducted to define the true distribution for the load measurement systemsâ uncertainty. A method that does not require a new uncertainty distribution experiment for multiple tests with different goals is presented. Moved mass tests confirm the uncertainty analysis using portable scales that provide accurate results. The polynomial chaos model used to find the uncertainty in the center of gravity calculation is derived. Karhunen-Loeve expansions, similar to Fourier series, are used to define the uncertainties to allow for the polynomial chaos expansion. PCE models are typically computed via the collocation method or the Galerkin method. The Galerkin method is chosen as the PCE method in order to formulate a more accurate analytical result. The derivation systematically increases from one uncertain load cell to all four uncertain load cells noting the differences and increased complexity as the uncertainty dimensions increase. For each derivation the PCE model is shown and the solution to the simulation is given. Results are presented comparing the polynomial chaos simulation to the Monte Carlo simulation and to the accurate scales. It is shown that the PCE simulations closely match the Monte Carlo simulations.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartDPriceThesis_V5.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectcenter of gravityen_US
dc.subject8-post testen_US
dc.subjectpolynomial chaos expansionen_US
dc.subjectGalerkin methoden_US
dc.titleEstimation of Uncertain Vehicle Center of Gravity using Polynomial Chaos Expansionsen_US
dc.typeThesisen_US
dc.contributor.departmentMechanical Engineeringen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineMechanical Engineeringen_US
dc.contributor.committeechairSouthward, Steve C.en_US
dc.contributor.committeememberSandu, Adrianen_US
dc.contributor.committeememberSandu, Corinaen_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-06172008-195556/en_US
dc.date.sdate2008-06-17en_US
dc.date.rdate2008-08-14
dc.date.adate2008-08-14en_US


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