Testing of Folding Wing-Tip for Gust Load Alleviation in High Aspect Ratio Wing

Cheung, Ronald C.; Rezgui, Djamel; Cooper, Jonathan E.; Wilson, Thomas

doi:10.2514/6.2019-1863

Cited by 9 publications

(9 citation statements)

References 7 publications

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“…By allowing the folding wingtip to rotate freely about the hinge inflight, an additional degree of freedom is introduced to the aeroelastic system of the wing which warrants closer examination to help understand its effect on the dynamic behavior of the overall system. One key observation, already established from previous experimental works 2,6 , is the reduction of peak wing-root bending moment in one-minus-cosine gust conditions. However, very limited test-based dynamic analysis of the folding wingtip concept has been performed.…”

Section: Introductionmentioning

confidence: 71%

Analyzing the Dynamic Behavior of a High Aspect Ratio Wing Incorporating a Folding Wingtip

Cheung¹,

Rezgui²,

Cooper³

et al. 2020

AIAA Scitech 2020 Forum

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High aspect ratio wings have been the focus of recent aircraft designs for improving fuel efficiency through induced drag reduction. The lengthened wingspan derived from these designs have led to the introduction of folding wingtips in order to meet airport gate width requirements. Previous numerical and experimental studies have demonstrated that folding wingtips can also provide a gust load alleviation benefit, when the folding wingtips are able to rotate freely about the hinge during the gust encounter. This work examines the dynamic characteristics and behavior of the folding wingtip, and the overall wing in such a configuration. A series of wind tunnel tests was conducted using a specially designed high aspect ratio wing model to establish its modal characteristics through application of a steppedsine frequency sweep, performed using a gust generator as well as a secondary aerodynamic surface incorporated into the wingtip as the excitation source. In addition, a pseudo-random gust sequence was used as a faster test method through broadband excitation, which yielded results that were in excellent agreement with the stepped-sine methods. Nomenclature Symbols α = Angle of attack γ = Hinge angle θ = Fold angle of the wingtip f = Frequency v = Wind tunnel velocity

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Section: Introductionmentioning

confidence: 71%

Analyzing the Dynamic Behavior of a High Aspect Ratio Wing Incorporating a Folding Wingtip

Cheung¹,

Rezgui²,

Cooper³

et al. 2020

AIAA Scitech 2020 Forum

Self Cite

View full text Add to dashboard Cite

show abstract

“…The steady aerodynamic tests showed that the folding wingtip provided static aerodynamic stability for both the free-hinge and stiff-hinge arrangements. Cheung et al [104] further investigated gust load alleviation of a flexible high aspect ratio wing with a folding wingtip using a low-speed wind-tunnel equipped with a vertical gust generator through a range of 1-cosine gust inputs. The orientation of the folding hinge axis of the folding tip was 10 degrees from the flow direction.…”

Section: Aeroelastic Controlmentioning

confidence: 99%

“…Ni et al [82] investigated the effect of morphing rate on the aeroelastic performance of a folding wing. Cheung et al [104] studied the effect of actuation frequency on the wing root bending moment of a folding wingtip. Hu et al [85] presented the effect of morphing rate and morphing modes (folding and unfolding) on the dynamic aeroelastic stability of the folding wing.…”

Section: Impact Of Actuation System/rates/forcesmentioning

confidence: 99%

Recent developments in the aeroelasticity of morphing aircraft

Ajaj

Parancheerivilakkathil

Amoozgar

et al. 2021

Progress in Aerospace Sciences

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“…Moreover, the achieved reduction from the wind tunnel measurements is higher than predicted. Cheung et al 15,16 added an aerodynamic surface into the wingtip to control the folding action. In a series of steady aerodynamic tests, they demonstrated that this device is capable of maintaining the orientation of the wingtip over a range of wind tunnel velocities and angles of attack.…”

Section: Introductionmentioning

confidence: 99%

The effect of folding wingtips on the worst-case gust loads of a simplified aircraft model

Balatti

Khodaparast

Friswell

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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In recent years, the development of lighter and more efficient transport aircraft has led to an increased focus on gust load alleviation. A recent strategy is based on the use of folding wingtip devices that increase the aspect ratio and therefore improve the aircraft performance. Moreover, numerical studies have suggested such a folding wingtip solution may incorporate spring devices in order to provide additional gust load alleviation ability in flight. It has been shown that wingtip mass, stiffness connection and hinge orientation are key parameters to avoid flutter and achieve load alleviation during gusts. The objective of this work is to show the effects of aeroelastic hinged wingtip on the problem of worst-case gust prediction and the parameterization and optimization of such a model for this particular problem, that is, worst-case gust load prediction. In this article, a simplified aeroelastic model of full symmetric aircraft with rigid movable wingtips is developed. The effects of hinge position, orientation and spring stiffness are considered in order to evaluate the performance of this technique for gust load alleviation. In addition, the longitudinal flight dynamics of a rigid aircraft with an elastic wing and folding wingtips is studied. Multi-objective optimizations are performed using a genetic algorithm to exploit the optimal combinations of the wingtip parameters that minimize the gust response for the whole flight envelope while keeping flutter speed within the safety margin. Two strategies to increase flutter speed based on the modification of the wingtip parameters are presented.

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Testing of Folding Wing-Tip for Gust Load Alleviation in High Aspect Ratio Wing

Cited by 9 publications

References 7 publications

Analyzing the Dynamic Behavior of a High Aspect Ratio Wing Incorporating a Folding Wingtip

Analyzing the Dynamic Behavior of a High Aspect Ratio Wing Incorporating a Folding Wingtip

Recent developments in the aeroelasticity of morphing aircraft

The effect of folding wingtips on the worst-case gust loads of a simplified aircraft model

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