INVESTIGATIONS INTO THE EFFECTS OF SECONDARY-FREQUENCY ADDITIONS ON SLENDER ROTATING STRUCTURES

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dc.contributor.advisorBalachandran, Balakumaren_US
dc.contributor.authorMeyer, Gregory Williamen_US
dc.contributor.departmentMechanical Engineeringen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2014-06-26T05:46:25Z
dc.date.available2014-06-26T05:46:25Z
dc.date.issued2014en_US
dc.description.abstractDrill strings are slender structures used extensively in drilling and mining operations. In this thesis work, secondary-frequency input additions to the drive speed input are considered and the resulting influence on system dynamics is examined. Experimental studies are conducted with a laboratory scale drill-string arrangement, and high-frequency and low-frequency additions are considered for cases in which the drive speed frequency is close to either a bending mode or torsion mode natural frequency. It is found that carefully chosen secondary-frequency additions can be used to attenuate undesirable system dynamics, especially, for rotary systems. To complement the experiments, numerical studies are conducted with a reduced-order model of the drill-string system. The obtained numerical results are found to be in reasonable agreement with the experimental results. Preliminary numerical results obtained in the presence of rotor-stator interactions are also included. In addition, areas in which the model construction will need further development are also discussed. The findings of this work can be useful for considering secondary-frequency addition based schemes for controlling bending and torsional motions of drill-string systems.en_US
dc.identifier.urihttp://hdl.handle.net/1903/15500
dc.language.isoenen_US
dc.subject.pqcontrolledMechanical engineeringen_US
dc.subject.pquncontrolledControlen_US
dc.subject.pquncontrolledDrillstringen_US
dc.subject.pquncontrolledVibrationsen_US
dc.titleINVESTIGATIONS INTO THE EFFECTS OF SECONDARY-FREQUENCY ADDITIONS ON SLENDER ROTATING STRUCTURESen_US
dc.typeThesisen_US

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