A comparative study of nonlinear aeroelastic models for high aspect ratio wings

Modaress-Aval, Amir Hossein; Bakhtiari-Nejad, Firooz; Dowell, Earl H.; Peters, David A.; Shahverdi, Hossein

doi:10.1016/j.jfluidstructs.2019.01.003

Cited by 18 publications

(6 citation statements)

References 27 publications

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“…We begin validating the gust input system as well as the the aeroelastic dynamic solvers by comparing the dynamic response of the clamped aircraft for a range of 1-cos gusts with small intensities. As per CS-25 and FAR regulations, gust lengths must be within the range (in meters) of ∈ [18,214]. Based on this, four types of gusts are selected, with the following gust lengths, [1 : 18 ; 2 : 67 ; 3 : 116 ; 4 : 214 ], gust intensity of 0 = 0.01 in Eq.…”

Section: Gust Responsementioning

confidence: 99%

“…Furthermore, only quadratic terms of the main variables are needed to capture the complete space of geometric nonlinearities. As for the modelling of the aerodynamic forces, although 2-D airfoil unsteady aerodynamics are still often used for high-aspect-ratio wing aeroelasticity, 3-D effects have been shown to play an important role [18] and will be considered here. The aerodynamic forces are obtained from the Doublet-Lattice Method (DLM) [19,20], which solves a linearization of the compressible, inviscid, unsteady flow equations in the 3-dimensional domain, and it is commonly used in linear aircraft aeroelastic analysis [21].…”

Section: Introductionmentioning

confidence: 99%

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A Non-Intrusive Nonlinear Aeroelastic Extension of Loads Packages with Application to Long Range Transport Aircraft Configuration

Cea

Palacios

2021

AIAA Scitech 2021 Forum

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A new method for constructing geometrically-nonlinear aeroelastic systems from standard linear models is applied to an industry-level aircraft configuration. The new approach seamlessly integrates with current aeroelastic load packages performing linear analysis based on generic finite-element models (FEMs) and aerodynamic influence coefficient matrices (AICs). We generalize the methodology to incorporate control inputs, find the trimmed aircraft state, or generate gusts disturbances, which can be employed separately or combined to obtain a simplified flight dynamics model for load analysis. An initial study of the aeroelastic response of a long range aircraft is presented. Linear and nonlinear results are introduced in static and dynamic computations of manoeuvres, trim, and gust disturbances. These are compared to commercial software calculations, showing the need for geometrically nonlinear analysis in the production environment of airplanes with ultra high aspect ratio wings.

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Section: Gust Responsementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Non-Intrusive Nonlinear Aeroelastic Extension of Loads Packages with Application to Long Range Transport Aircraft Configuration

Cea

Palacios

2021

AIAA Scitech 2021 Forum

View full text Add to dashboard Cite

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“…Aspect-ratio increase is usually achieved by a compromise in chord reduction and span increase that enables aerodynamic advantages at typical operating conditions, namely in cruise and high g's maneuvers, without a severe increase of the structural weight. This design solution has however an impact on the wing's structure which is now more prone to higher deflections and root bending moments with the increase of wing span, which may result in geometric nonlinearities [1][2][3][4][5][6][7][8][9]. Hazardous aeroelastic phenomena such as flutter may arise from this higher flexibility in the flight envelope.…”

Section: Introductionmentioning

confidence: 99%

On the Design of Aeroelastically Scaled Models of High Aspect-Ratio Wings

et al. 2020

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Recently, innovative aircraft designs were proposed to improve aerodynamic performance. Examples include high aspect ratio wings to reduce the aerodynamic induced drag to achieve lower fuel consumption. Such solution when combined with a lightweight structure may lead to aeroelastic instabilities such as flutter at lower air speeds compared to more conventional wing designs. Therefore, in order to ensure safe flight operation, it is important to study the aeroelastic behavior of the wing throughout the flight envelope. This can be achieved by either experimental or computational work. Experimental wind tunnel and scaled flight test models need to exhibit similar aeroelastic behavior to the full scale air vehicle. In this paper, three different aeroelastic scaling strategies are formulated and applied to a flexible high aspect-ratio wing. These scaling strategies are first evaluated in terms of their ability to generate reduced models with the intended representations of the aerodynamic, structural and inertial characteristics. Next, they are assessed in terms of their potential in representing the unsteady non-linear aeroelastic behavior in three different flight conditions. The scaled models engineered by exactly scaling down the internal structure suitably represent the intended aeroelastic behavior and allow the performance assessment for the entire flight envelope. However, since both the flight and wind tunnel models are constrained by physical and budgetary limitations, custom built structural models are more likely to be selected. However, the latter ones are less promising to study the entire flight envelope.

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“…Thus, a simple yet realistic model and analysis framework that can accurately assess the flight performances of a largely deformed highly flexible aircraft, and can fully account for the coupling between flight dynamics and both structural nonlinearity and unsteady aerodynamics, which play a key role in the vehicle's static and dynamic characteristics, are of paramount importance in the analysis and design of these highly flexible aircrafts [3][4][5]. Such models are typically built using nonlinear beam representations of the structure [6][7][8], with either unsteady strip theory [9][10][11][12][13] or unsteady vortex lattice aerodynamics [14,15].…”

Section: Introductionmentioning

confidence: 99%

A Comprehensive Framework for Coupled Nonlinear Aeroelasticity and Flight Dynamics of Highly Flexible Aircrafts

et al. 2020

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A framework to model and analyze the coupled nonlinear aeroelasticity and flight dynamics of highly flexible aircrafts is presented. The methodology is based on the dynamics of 3D co-rotational beams. The coupling of axial, bending and torsional effects is added to the stiffness and mass matrices of Euler-Bernoulli beam to capture the most relevant characteristics of a real wing structure. The finite-state aerodynamic model is coupled with the structural model to simulate the unsteady aerodynamics. A scheme of mixed end-point and mid-point time-marching algorithms is proposed and applied into the implicit predictor-corrector integration, where the end-point algorithm is used in the predictor step for efficiency and mid-point algorithm in corrector step for accuracy. The ground, body and airflow axes for flight dynamics are re-defined by the global and elemental ones for structural dynamics, followed by the redefinitions of local Euler angles and airflow angles of each element. The framework can be used for quick analyses of flexible aircrafts in conceptual and preliminary design phases, including linear and nonlinear trim, aerodynamic load estimation, stability assessment, time-domain simulations and flight performance evaluations. The results show the payload mass and its distributions will significantly affect the trim state and longitudinal stability of highly flexible aircrafts.

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A comparative study of nonlinear aeroelastic models for high aspect ratio wings

Cited by 18 publications

References 27 publications

A Non-Intrusive Nonlinear Aeroelastic Extension of Loads Packages with Application to Long Range Transport Aircraft Configuration

A Non-Intrusive Nonlinear Aeroelastic Extension of Loads Packages with Application to Long Range Transport Aircraft Configuration

On the Design of Aeroelastically Scaled Models of High Aspect-Ratio Wings

A Comprehensive Framework for Coupled Nonlinear Aeroelasticity and Flight Dynamics of Highly Flexible Aircrafts

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