Dynamic aero-structural response of an elastic wing model

Kämpchen, M.; Dafnis, Athanasios; Reimerdes, Hans-Günther; Britten, G.; Ballmann, J.

doi:10.1016/s0889-9746(03)00090-2

Cited by 10 publications

(9 citation statements)

References 8 publications

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“…The aerodynamics are normally modeled using a panel code (usually the Doublet-Lattice Method) (30) or a 2D unsteady aerodynamic model capable of predicting flow separation (5,16) . The structures are usually modeled as beams using analytical (5,16,30) or finite element models (23) . Some computational frameworks were specially developed to study the coupling of flight mechanics with non-linear aeroelasticity of very flexible high aspect-ratio wings (namely the high-altitude, long-endurance aircraft) such as ASWING (17) , NATASHA (29,31) , UM/NAST (12,13,34) , NANSI (38) and SHARP (27,28) .…”

Section: Introductionmentioning

confidence: 99%

Non-linear aeroelastic response of high aspect-ratio wings in the frequency domain

et al. 2017

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A current trend in the aeronautic industry is to increase the wing aspect ratio to enhance aerodynamic efficiency by reducing the induced drag and thus reduce fuel consumption. Despite the associated benefits of a large aspect ratio, such as higher lift-to-drag ratios and range, commercial aircraft usually have a relatively low aspect ratio. This is partially explained by the fact that the wing becomes more flexible with increasing aspect ratio and thus more prone to large deflections, which can cause aeroelastic instability problems such as flutter. In this work, an aeroelastic study is conducted on a rectangular wing model of 20 m span and variable chord for a low subsonic speed condition to evaluate the differences between linear and non-linear static aeroelastic responses. Comparisons between linear and non-linear displacements, natural frequencies and flutter boundary are performed. An in-house non-linear aeroelastic framework was employed for this purpose. In this work, the influence of the aspect ratio and geometric non-linearity (highly deformed states) is assessed in terms of aeroelastic performance parameters: flutter speed and divergence speed. A nearly linear correlation of flutter speed difference (relative to linear analysis results) with vertical-tip displacement difference is observed. The flutter and divergence speeds vary substantially as the wing aspect ratio increases, and the divergence speeds always remain above the flutter speed. Furthermore, the flutter mechanism was observed to change as the wing chord is decreased.

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Section: Introductionmentioning

confidence: 99%

Non-linear aeroelastic response of high aspect-ratio wings in the frequency domain

et al. 2017

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“…Several numerical works have been published over the past few decades using low-/medium-fidelity models for the non-linear aeroelastic analyses of high-aspect-ratio wings and highly flexible aircraft at low subsonic conditions. The structural models used consist in general of analytic (4,19,33,40) or finite element beam models (28) with constant geometry and material properties. The aerodynamic models employed in these studies use doublet-lattice method (DLM) (40) and 2D unsteady aerodynamics models (33) with flow separation prediction (4,19,21) .…”

Section: Introductionmentioning

confidence: 99%

“…Despite the large number of numerical studies, just a few experimental analyses related to non-linear aeroelasticity of high-aspect-ratio wings are available in the literature. All known experimental data found is based on simple planar straight wings at low subsonic speeds, with highly flexible structures designed to: deform significantly (21,28) ; exhibit flutter and limit cycle oscillation (LCO) under aerodynamic loading at speeds within the range of the wind tunnel where they are going to be tested (57,59) ; study gust response (58,60) . Some of these studies include the effect of slender bodies at the wing tip or at different span-wise positions, Non-linear aeroelastic analysis in the time domain... which in general causes reduction of the frequency of the first torsional mode of vibration.…”

Section: Introductionmentioning

confidence: 99%

Non-linear aeroelastic analysis in the time domain of high-aspect-ratio wings: Effect of chord and taper-ratio variation

et al. 2016

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Commercial jets usually have relatively low-aspect-ratio wings, in spite of the associated benefits of increasing the wing aspect-ratio, such as higher lift-to-drag ratios and ranges. This is partially explained by the fact that the wing becomes more flexible by increasing the aspect-ratio that results in higher deflections which can cause aeroelastic instability problems such as flutter. An aeroelastic computational framework capable of evaluating the effects of geometric non-linearities on the aeroelastic performance of high-aspect-ratio wings has been developed and validated using numerical and experimental data. In this work, the aeroelastic performance of a base wing model with 20 m span and 1 m chord is analysed and the effect of changing the wing chord or the taper-ratio is determined. The non-linear static aeroelastic equilibrium solutions are compared in terms of drag polar, root bending moment and natural frequencies, and the change in the flutter speed boundary is assessed as a function of aspect-ratio using a time-marching approach.

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“…12,13 The structural models usually consist of analytical beam models 11–13 or finite element beam models. 14…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, just a few experimental studies are available, which are based on simple planar rectangular wings with constant cross-sectional properties at low subsonic speeds, with highly flexible structures planned to deform considerably, 14,33 to encounter limit cycle oscillation (LCO) 34 or to study the gust response. 35…”

Section: Introductionmentioning

confidence: 99%

The effect of stiffness and geometric parameters on the nonlinear aeroelastic performance of high aspect ratio wings

Afonso

Leal

Vale

et al. 2016

Proceedings of the Institution of Mechanical Engineers, Part G:

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The increase in wing aspect ratio is gaining interest among aircraft designers in conventional and joined-wing configurations due to the higher lift-to-drag ratios and longer ranges. However, current transport aircraft have relatively small aspect ratios due their increased structural stiffness. The more flexible the wing is more prone to higher deflections under the same operating condition, which may result in a geometrical nonlinear behavior. This nonlinear effect can lead to the occurrence of aeroelastic instabilities such as flutter sooner than in an equivalent stiffer wing. In this work, the effect of important stiffness (inertia ratio and torsional stiffness) and geometric (sweep and dihedral angles) design parameters on aeroelastic performance of a rectangular high aspect ratio wing model is assessed. The torsional stiffness was observed to present a higher influence on the flutter speed than the inertia ratio. Here, the decrease of the inertia ratio and the increase of the torsional stiffness results in higher flutter and divergence speeds. With respect to the geometric parameters, it was observed that neither the sweep angle nor the dihedral angle variations caused a substantial influence on the flutter speed, which is mainly supported by the resulting smaller variations in torsion and bending stiffness due to the geometric changes.

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Dynamic aero-structural response of an elastic wing model

Cited by 10 publications

References 8 publications

Non-linear aeroelastic response of high aspect-ratio wings in the frequency domain

Non-linear aeroelastic response of high aspect-ratio wings in the frequency domain

Non-linear aeroelastic analysis in the time domain of high-aspect-ratio wings: Effect of chord and taper-ratio variation

The effect of stiffness and geometric parameters on the nonlinear aeroelastic performance of high aspect ratio wings

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