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dc.contributor.authorPaxton, Scotten_US
dc.date.accessioned2014-03-14T20:52:05Z
dc.date.available2014-03-14T20:52:05Z
dc.date.issued1997-07-23en_US
dc.identifier.otheretd-63197-94758en_US
dc.identifier.urihttp://hdl.handle.net/10919/36876
dc.description.abstract

There has been much recent research on the control of complex sound fields in enclosed vibrating structures via active control techniques. Active Structural Acoustic Control (ASAC) has shown much promise for reducing interior cabin noise in aircraft by applying control forces directly to the fuselage structure. Optimal positioning of force actuators for ASAC presents a challenging problem however, because a detailed knowledge of the structural-acoustic coupling in the fuselage is required.

This work is concerned with the development of a novel experimental technique for examining the forced harmonic vibrations of an aircraft fuselage and isolating the acoustically well-coupled motions that cause significant interior noise. The developed system identification technique is itself based upon an active control system, which is used to approximate the disturbance noise field in the cabin and apply an inverse excitation to the fuselage structure. The resulting shell vibrations are recorded and used to optimally locate piezoelectric (PZT) actuators on the fuselage for ASAC testing.

Experiments for this project made use of a Cessna Citation III aircraft fuselage test rig. Tests were performed at three harmonic disturbance frequencies, including an acoustic resonance, an off-resonance, and a structural resonance case. In all cases, the new system identification technique successfully isolated a simplified, low-magnitude vibration pattern from the total structural response caused by a force disturbance applied at the fuselage's rear engine mount. These measured well-coupled vibration components were used for positioning candidate piezoelectric actuators on the fuselage shell. A genetic algorithm search provided an optimal subset of actuators for use in an ASAC system. ASAC tests confirmed the importance of actuator location, as the optimal sets outperformed alternate groupings in all test cases. In addition, significant global control was achieved, with sound level reductions observed throughout the passenger cabin with virtually no control spillover.

en_US
dc.publisherVirginia Techen_US
dc.relation.haspartETD.PDFen_US
dc.rightsI hereby grant to Virginia Tech or its agents the right to archive and to make available my thesis or dissertation in whole or in part in the University Libraries in all forms of media, now or hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation.en_US
dc.subjectactive controlen_US
dc.subjectoptimizationen_US
dc.subjectsystem identificationen_US
dc.subjectASACen_US
dc.titleSystem Identification and Optimization Methodologies for Active Structural Acoustic Control of Aircraft Cabin Noiseen_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.committeechairFuller, Christopher R.en_US
dc.contributor.committeememberBurdisso, Ricardo A.en_US
dc.contributor.committeememberCudney, Harley H.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-63197-94758/en_US
dc.date.sdate1997-07-23en_US
dc.date.rdate1998-08-04
dc.date.adate1997-08-04en_US


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