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Full-Text Articles in Mechanical Engineering

Robust-Adaptive Magnetic Bearing Control Of Flexible Matrix Composite Rotorcraft Driveline, Hans August Desmidt, Kon-Well Wang, Edward Smith Jan 2008

Robust-Adaptive Magnetic Bearing Control Of Flexible Matrix Composite Rotorcraft Driveline, Hans August Desmidt, Kon-Well Wang, Edward Smith

Faculty Publications and Other Works -- Mechanical, Aerospace and Biomedical Engineering

Recent studies demonstrate that a key advantage of Flexible Matrix Composite (FMC) shaft technology is the ability to accommodate misalignments without need for segmenting or flexible couplings as required by conventional alloy and graphite/epoxy composite shafts. While this is indeed a very promising technology for rotorcraft driveshafts, the high damping loss-factor and thermal stiffness and damping sensitivities of the urethane matrix, makes FMC shafting more prone to self-heating and whirl instabilities. Furthermore, the relatively low bending stiffness and critical speeds of FMC shafts makes imbalance vibration a significant challenge to supercritical operation. To address these issues and advance the state-of-the-art, …


Experimental Investigation Of Active Control Of Bluff Body Vortex Shedding, Ilteris Koc Jan 2008

Experimental Investigation Of Active Control Of Bluff Body Vortex Shedding, Ilteris Koc

Mechanical & Aerospace Engineering Theses & Dissertations

Mean and fluctuating forces acting on a body are strongly related to vortex shedding generated behind it. Therefore, it is possible to obtain substantial reductions of at least the unsteady forces if vortex shedding is controlled or its regularity is reduced. While conventional active flow control methods are mainly concerned with direct interaction with, and alteration of, the mean flow about a body, modern techniques involve altering existing flow instabilities using relatively small inputs to obtain large-scale changes of mean flows. Aerodynamic flow control may be intended to delay or suppress boundary layer separation through creation of a boundary layer …