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A dual reaction-mass dynamic vibration absorber for active vibration control

Traditional dynamic vibration absorbers (DVAs) consist of a mass-spring-damper system and are an effective means of attenuating structural vibration over a narrow frequency band. The effective bandwidth of the DVA can be increased by the addition of an externally controlled force, generally applied between the reaction-mass and the primary structure. Such devices are known as hybrid DVAs. This thesis presents a new hybrid DVA configuration which utilizes two reaction-masses in parallel. On this proposed hybrid dual-mass (DM) DVA, the control force is applied between the reaction-masses. It is shown that in broadband control applications, the proposed DM-DVA requires less control force to achieve the same primary attenuation as the traditional hybrid single-mass (SM) DVA. The hybrid DM-DVA was compared to the hybrid SM-DVA with two tests. A numerical simulation of the hybrid DVAs attenuating a single-degree-of-freedom structure was performed. To achieve an equal amount of primary attenuation, the hybrid SM-DVA required 65% higher root-mean-square (RMS) control effort than the hybrid DV-DVA. The numerical model also demonstrated that the hybrid DM-DVA was less sensitive to changes in the system as compared to the hybrid SM-DVA. Additionally, a prototype hybrid DVA was built which could be configured as either the hybrid SM or DM-DVA. The prototype hybrid DVA was used with the feedforward Filtered-X LMS algorithm to control the vibration of a fixed-free beam. The hybrid SM and DM-DVAs attenuated the primary response by a factor of 11.5 and 12.3, while requiring control efforts of 4.9 and 2.7 V/N RMS, respectively. Thus, the hybrid DM-DVA required 45% less control effort while yielding a higher attenuation ratio in this experiment. These results demonstrate the superior performance of the proposed DM-DVA for broadband control applications as compared to the traditional SM-DVA. / Master of Science

Identiferoai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/44808
Date18 September 2008
CreatorsHeilmann, John
ContributorsMechanical Engineering, Burdisso, Ricardo A., Cudney, Harley H., Hendricks, Scott L.
PublisherVirginia Tech
Source SetsVirginia Tech Theses and Dissertation
LanguageEnglish
Detected LanguageEnglish
TypeThesis, Text
Formatx, 130 leaves, BTD, application/pdf, application/pdf
RightsIn Copyright, http://rightsstatements.org/vocab/InC/1.0/
RelationOCLC# 35731363, LD5655.V855_1996.H455.pdf

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