Trailing Edge Flap Activated by a Piezo-Induced Bending-Torsion Coupled Beam

Bernhard, Andreas; Chopra, Inderjit

doi:10.4050/jahs.44.3

Cited by 24 publications

(13 citation statements)

References 18 publications

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“…For practical implementation, the trend has been to use adaptive materials such as piezoelectric or magnetostrictive actuator devices to actively control the flap. This type of actuation has been considered by several researchers including Spangler and Hall, 6 Bernhard and Chopra, 7 Fulton and Ormiston, 8 and Prechtl and Hall. 9 The force and stroke producing capability of adaptive materials based actuation is limited.…”

Section: Introductionmentioning

confidence: 99%

Actuator saturation and its influence on vibration reduction by actively controlled flaps

Cribbs¹,

Friedmann²

2001

19th AIAA Applied Aerodynamics Conference

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The influence of actuator saturation on the vibration reduction abilities of an actively controlled flap is investigated. An aeroelastic model of a four bladed hingeless rotor with a free wake is used for the analyses. Three methods for constraining flap deflections are studied at two limiting values, two and four degrees, of maximum flap deflection. Results indicate that neither scaling nor clipping of the optimal control flap deflection to the maximum flap deflection provides acceptable vibration reduction. A newly developed control method with saturation constraints shows exceptional reduction of vibrations. This new control method reduces vibrations to similar levels as the unconstrained optimal control while constraining maximum flap deflections to the limiting values. Nomenclature Blade lift curve slope Blade chord Trailing edge flap chord Coefficient of drag Helicopter coefficient of weight Weighting multiplier for W u weighting matrix Blade bending stiffnesses in flap and lead-lag 4/rev vibratory hub shears in longitudinal, lateral and vertical directions, respectively Quadratic performance index for vibration control Cdo

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Section: Introductionmentioning

confidence: 99%

Actuator saturation and its influence on vibration reduction by actively controlled flaps

Cribbs¹,

Friedmann²

2001

19th AIAA Applied Aerodynamics Conference

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“…The first five harmonics were reduced by 68 and 73% respectively. The losses in the amplification system of smart actuators and the penalty incurred in adding the mass of the actuatorflap-unit aft of the 1/4 chord line are disadvantages of active flaps [56]. Another drawback is the drag and hence power increase associated with flap deflection.…”

Section: Hc Active Flapmentioning

confidence: 99%

“…A different flap actuation design is proposed in [56]. A 2-bladed model with 1.83 m diameter was built and hovertested.…”

Section: Active Trailing Edge Flapmentioning

confidence: 99%

Active rotor control for helicopters: individual blade control and swashplateless rotor designs

Kessler¹

2011

CEAS Aeronaut J

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Modern helicopters still suffer from many problems that hinder a further increase in their efficiency, acceptance and hence their market share. The high level of vibrations and the noise generated by the rotor are the most important reasons for this. Vibrations are problematic not only for pilot and passenger comfort, but also give rise to an increase in maintenance effort. The high noise level limits the acceptance of helicopters in the public, e.g. landing of helicopters on or close to hospitals during Emergency Medical Services missions. High noise levels also lead to an early aural detection during military missions. Further drawbacks of helicopters are the high fuel consumption in high-speed forward flight and hence low range, limited speed of flight, etc. To overcome these drawbacks, active rotor control technologies have been investigated for a long time. Many different approaches have been investigated and most of them are not being followed any more. First investigations started with socalled Higher Harmonic Control (HHC) which has been replaced by Individual Blade Control (IBC). In a previous paper motivation on active rotor control technology was recapitulated as well as achievements on HHC. This paper continues that work and gives a survey on IBC concepts and achievements. An outlook on the idea of the swashplateless helicopter concludes the paper.

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“…Now, the functionally graded piezoelectric materials (FGPMs), as intelligent materials, have been used extensively in applications of sensors and actuators in the micro-electro-mechanical system (MEMS) [2,3] and smart structures [4][5][6][7][8][9] , especially in the medical and aerospace industry [10] . Generally, FGPMs are inhomogeneous with material properties varying spatially in a continuous manner, hence exhibiting more attractive features when compared to conventional laminated ma-…”

mentioning

confidence: 99%

Three-dimensional analytical solution for a transversely isotropic functionally graded piezoelectric circular plate subject to a uniform electric potential difference

Ding

Chen

2008

Sci. China Ser. G-Phys. Mech. Astron.

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This paper studies the problem of a functionally graded piezoelectric circular plate subjected to a uniform electric potential difference between the upper and lower surfaces. By assuming the generalized displacements in appropriate forms, five differential equations governing the generalized displacement functions are derived from the equilibrium equations. These displacement functions are then obtained in an explicit form, which still involve four undetermined integral constants, through a step-by-step integration which properly incorporates the boundary conditions at the upper and lower surfaces. The boundary conditions at the cylindrical surface are then used to determine the integral constants. Hence, three-dimensional analytical solutions for electrically loaded functionally graded piezoelectric circular plates with free or simply-supported edge are completely determined. These solutions can account for an arbitrary material variation along the thickness, and thus can be readily degenerated into those for a homogenous plate. A numerical example is finally given to show the validity of the analysis, and the effect of material inhomogeneity on the elastic and electric fields is discussed.functionally graded material, piezoelectric material, circular plates, uniform electric potential, direct displacement methodThe time-line of humankind is located at the dawn of a new age, namely, the Smart Materials Age [1] . Now, the functionally graded piezoelectric materials (FGPMs), as intelligent materials, have been used extensively in applications of sensors and actuators in the micro-electro-mechanical system (MEMS) [2,3] and smart structures [4][5][6][7][8][9] , especially in the medical and aerospace industry [10] . Generally, FGPMs are inhomogeneous with material properties varying spatially in a continuous manner, hence exhibiting more attractive features when compared to conventional laminated ma-

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Trailing Edge Flap Activated by a Piezo-Induced Bending-Torsion Coupled Beam

Cited by 24 publications

References 18 publications

Actuator saturation and its influence on vibration reduction by actively controlled flaps

Actuator saturation and its influence on vibration reduction by actively controlled flaps

Active rotor control for helicopters: individual blade control and swashplateless rotor designs

Three-dimensional analytical solution for a transversely isotropic functionally graded piezoelectric circular plate subject to a uniform electric potential difference

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