Flutter and Divergence Characteristics of Composite Plate Wing

Kassem, M. E.; Negm, Hany Mohamed; Elshafei, M. Adnan

doi:10.21608/asat.2013.22181

Cited by 6 publications

(4 citation statements)

References 12 publications

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“…where, (26) In this study, the composite plate is considered as a thin plate where the panel is divided into several boxes for aerodynamics modelling. The thin composite panel is divided equally into 20 boxes in the spanwise direction and 5 boxes in the chordwise.…”

Section: Doublet Lattice Methodsmentioning

confidence: 99%

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Aeroelastic assessment of cracked composite plate by means of fully coupled finite element and Doublet Lattice Method

Abdullah

Curiel-Sosa

Akbar

2018

Composite Structures

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This paper presents an investigation on flutter speed of cracked composite plates. This work is divided into two sections: (a) variation of crack length at a fixed location on the plate, and (b) variation of crack location on the plate with a fixed crack length, modelled as a unidirectional composite for 0 0 , 90 0 and 135 0 orientations. Mori-Tanaka homogenization model is applied to obtain the effective composite constitutive properties as the function of fiber and matrix volume fraction. Doublet Lattice Method (DLM) is used to calculate the unsteady aerodynamic forces, i.e., lift distributions. It is found that the existence of small crack ratio on the composite plate (less than 0.4) has triggered an increment of the flutter speed. To support this statement, flutter response modes for each crack ratio are plotted, where the structure appears to be more stiffened than the undamaged plate. However, the crack results in the reduction of flutter speed when the crack ratio reaches 0.5. For the crack location assessment, the flutter speed increases as the crack location moves from the root to the tip due to the reduction of flutter frequency. The results show a good agreement with the validation using Strip Theory considering unsteady aerodynamics.

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Section: Doublet Lattice Methodsmentioning

confidence: 99%

“…The same coupling procedure between DLM and structural modelling using modified higher order shear deformation theory was performed by Abbas et al [26] to estimate the flutter speed. There is another finite element that can be used, e.g.…”

Section: Aerostructural Couplingmentioning

confidence: 99%

Aeroelastic assessment of cracked composite plate by means of fully coupled finite element and Doublet Lattice Method

Abdullah

Curiel-Sosa

Akbar

2018

Composite Structures

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“…The result of the study showed that composite layup orientation angles have played a great role which can be considered as a design parameter for the aero elastic instability analysis of on the wing flutter and divergence speeds. Modified higher order shear deformation theory for the structural computation and Doublet point method for the aerodynamic unsteady flow formulations were applied for the aeroelastic instability analysis [24]. The researchers used U-g method for flutter and divergence velocities estimations.…”

Section: Introductionmentioning

confidence: 99%

Estimation of the divergence characteristics of a jet transport aircraft wing using numerical method.

Ferede

2022

Preprint

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The goal of the present paper work is to demonstrate the use of numerical matrix iteration technique to obtain the divergence speed of a jet transport aircraft wing by employing aerodynamic strip theory. Aerodynamics strip theory is employed to obtain the divergence speeds for a finite (Three Dimensional) wing and for an infinite (Two dimensional) wing by matrix iteration technique. The aircraft wing is divided in to a number of Multhopp’s stations. The elastic property of the wing of a typical jet transport is considered for this analysis. Assuming a straight elastic axis, the matrix of torsional influence coefficients associated with Multhopp’s stations has been computed. A MATLAB code is used to iterate the matrix to arrive at the required convergent approximate solution. The solution converges about after ten iterations of the matrix. It is observed that torsional divergence speed estimated on the basis of strip theory without finite span correction is about 18% lower than the divergence speed estimated on the basis of strip theory with finite span correction. Two-dimensional torsional divergence analysis based on strip theory yields conservative torsional divergence speed. A tentative increase of 20 % in torsional stiffness resulted in about 15.5 percent increase in torsional divergence speed of a three-dimensional wing. This shows that divergence speed of a wing is directly proportional to the square root of torsional stiffness. This corroborates the result obtained for a two-dimensional wing. The result of the findings will be mandatory to high performance modern airplane designers for aeroelastic analysis.

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“…Examples of the former case include: Refs. [?, [9][10][11][12], which approximated composite lifting surfaces as cantilever plates and optimised for aeroelastic stability, neglecting the effects on structural weight; and Refs. [3,7,[13][14][15][16], which used wing-box models, including skins, spar and ribs, in order to obtain a more accurate structural and aeroelastic performance characterisation.…”

Section: Introductionmentioning

confidence: 99%

A robust and reliability-based aeroelastic tailoring framework for composite aircraft wings

Othman

Silva

Cabral

et al. 2019

Composite Structures

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This paper presents a multi-level aeroelastic tailoring framework for the optimisation of composite aircraft wings. The framework is capable of structural sizing and produces detailed composite ply configurations through robust and reliability-based design optimisation, and is demonstrated on a representative regional jet airliner finite element wing box model. The optimisation procedure is divided into two levels. The first level optimises the wing structure for minimum weight subject to multiple constraints including strain, buckling, aeroelastic stability and gust response. These first level solutions are then fed into the second level to be further optimised for robustness or reliability by considering uncertainties in material properties at ply level. Both the principles of robust and reliability-based design optimisation can also be used in combination to ensure a balance between the robustness and reliability of the structural performance. In order to keep computations to an acceptable cost, the second level optimisation employs the Polynomial Chaos Expansion method to approximate the effect of probabilistic uncertainty on structural performance. In comparison to the original benchmark wing, the framework produces an overall weight reduction of 32.1%, despite a 1.5% increase from the first to the second level optimisation that accounts for stochastic design variations.

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Flutter and Divergence Characteristics of Composite Plate Wing

Cited by 6 publications

References 12 publications

Aeroelastic assessment of cracked composite plate by means of fully coupled finite element and Doublet Lattice Method

Aeroelastic assessment of cracked composite plate by means of fully coupled finite element and Doublet Lattice Method

Estimation of the divergence characteristics of a jet transport aircraft wing using numerical method.

A robust and reliability-based aeroelastic tailoring framework for composite aircraft wings

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