Airfoil-shaped Extension-twist-coupled Composite Star-beams For Rotor Blade Tip Applications

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Airfoil-shaped Extension-twist-coupled Composite Star-beams For Rotor Blade Tip Applications

Show simple item record Mahadev, Sthanu en_US 2011-10-11T20:48:47Z 2011-10-11T20:48:47Z 2011-10-11 January 2011 en_US
dc.identifier.other DISS-11317 en_US
dc.description.abstract Rotorcraft blade tips provide the most effective region for aerodynamic control. Rotor blade airloads are proportional to dynamic pressure and as a consequence are typically the highest in the distal blade tip region. Therefore, blade control using aerodynamic forces and moments is most effectively accomplished over the distal region of the blade. Composite materials represent the preferred material option for modern rotor blade design, especially in the field of rotorcraft and wind energy, due to superior strength-to-weight ratio, fatigue resistance and their ability to be easily tailored to incorporate different coupling (bend-twist, extension-twist, etc.) among elastic modes of deformation within the structure. An additional form of tailoring can produce compliant mechanisms: structures that are capable of producing a deformation such that the resulting displacement field is similar to the kinematics of an actual mechanism. In prior research, a family of tailored composite structures referred to as "star-beams" and "modified star-beams" have been proposed and investigated as viable candidates for tension-torsion bar applications, including the case of extension-twist coupling, for which "star-beams" preserve the high level of coupling achievable in composite strips. The present work seeks to develop and investigate the extension of prior work to the case of an extension-twist coupled torsionally compliant integral blade tip configuration. The implementation of this structural concept ensures a smooth outer blade-lifting surface and that the smoothness is preserved throughout the desired deformation range while allowing out of plane cross-sectional warping via relative longitudinal sliding along the blade joints. This work focuses on passive control of pitch applications via extension-twist coupling as a result of changes in axial force, typically obtained as a result of change in centrifugal load with rotor speed for a constant thickness, symmetric NACA 0012 airfoil. An ABAQUS based finite element approach is employed to obtain a first characterization of the integral blade tip pitch response to changes in axial load and torque. en_US
dc.description.sponsorship Dancila, Dragos-Stefan en_US
dc.language.iso en en_US
dc.publisher Aerospace Engineering en_US
dc.title Airfoil-shaped Extension-twist-coupled Composite Star-beams For Rotor Blade Tip Applications en_US
dc.type M.S. en_US
dc.contributor.committeeChair Dancila, Dragos-Stefan en_US Aerospace Engineering en_US Aerospace Engineering en_US University of Texas at Arlington en_US masters en_US M.S. en_US

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