Introduction to Aircraft Aeroelasticity and Loads

Wright, J.F.; Cooper, Jonathan E.

doi:10.1002/9781118700440

Cited by 145 publications

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“…A symmetry at the root was assumed to consider the reflection from the wind tunnel wall 29 . The inclusion of 0.5% of structural damping prevented the triggering of soft flutter modes 2,29 . Figure 14 and Figure 15 show the variation of the first aeroelastic instability speed as the wing sweep angle and the rib orientation are changed.…”

Section: E First Aeroelastic Instability Speed Analysismentioning

confidence: 99%

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Impact of the Wing Sweep Angle and Rib Orientation on Wing Structural Response for Un-Tapered Wings

François

Cooper

2016

57th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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In this paper, the impact of varying the sweep angle of the spar and the rib orientation on wing structural deformation is investigated and related to a beam model. 3D Finite-Element wing wind tunnel models with varying wing sweep angle and rib orientation are considered. The wing models tip displacement and tip twist under static tip loads and aerodynamic loading are considered as well as the wing's natural frequencies, aeroelastic instability speed and maximum root bending moment during a gust encounter. A framework to characterise Euler-Bernoulli beam properties on wings with geometric coupling is then developed and validated to relate the stiffness and bend/twist coupling parameter to the full FE models.

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Section: E First Aeroelastic Instability Speed Analysismentioning

confidence: 99%

“…The science of aeroelasticity focuses on the deformation and response of structure under aerodynamic, inertia and elastic forces 2 . Applied to wing design, aeroelasticity can control the wing shape during cruise flight, control the wing response to gust encounters and also prevent the occurrence of flutter and divergence.…”

Section: Introductionmentioning

confidence: 99%

Impact of the Wing Sweep Angle and Rib Orientation on Wing Structural Response for Un-Tapered Wings

François

Cooper

2016

57th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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“…The linear aeroelastic equations of motion in generalized coordinates, excited by atmospheric gust, are formulated in the Laplace domain using the standard formulation [5] as …”

Section: Aeroelastic Equations Of Motionmentioning

confidence: 99%

“…Certification requirements specify the discrete gust load cases considering the aircraft in level flight subject to symmetrical vertical and lateral gusts with a "1-cosine" velocity profile having gust gradient (half of the gust wavelength) and asking for several gust gradients between 30ft and 350ft to be investigated in order to determine the critical conditions [1], [5]. The certification specifications also cover unchecked and checked abrupt pitching manoeuvres [1], [5] resulting from either a sudden or sinusoidal displacement of the elevator.…”

Section: Application To Gust and Manoeuvre Loads Predictionmentioning

confidence: 99%

“…The time domain approaches defined in the airworthiness regulations [1], [5] are based upon finding the tuned "1 -Cosine" gust that causes the worst response. Previous work in the FFAST EU FP7 project [6], [7], [8] investigated the use of several surrogate models and optimization methods for fast and efficient prediction of the worst case gust loads for each IQ of a large transport aircraft model.…”

Section: Introductionmentioning

confidence: 99%

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Parametric reduced order model approach for rapid dynamic loads prediction

Castellani¹,

Lemmens

Cooper³

2016

Aerospace Science and Technology

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A parametric reduced order methodology for loads estimation is described that produces a fast and accurate prediction of gust and manoeuvre loads for different flight conditions and structural parameter variations. The approach enables efficient prediction of the peak loads whilst maintaining the correlated time histories for different loads. It is then possible to determine correlated loads plots with reduced computation without losing accuracy. The effectiveness of the methodology is demonstrated by considering loads arising from families of gusts and pitching manoeuvres acting upon a numerical transport aircraft aeroservoelastic model with varying flight conditions and structural properties.

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Sliding Mode Observer Controller Design for a Two Dimensional Aeroelastic System with Gust Load

Yuan¹,

Qiu²,

Wang³

2018

Asian Journal of Control

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The aim of this paper is to develop state estimation and sliding mode control schemes for the vibration suppression of an underactuated wing aeroelastic system in the presence of a gust load disturbance. Ignoring structural elastic deformation and using the concentrated elastic system (spring) to simulate the overall elastic deformation, this aeroelastic model consists of a straight wing and spring system, describing flap and pitch freedoms. The corresponding dynamic motion equation is established using the Lagrange method, and the gust is modeled as a typical "1-cosine" gust. The aerodynamic lift and moment on the wing are computed by strip theory. The open loop system exhibits the limit cycle oscillations (LCOs) at a certain freestream velocity. The objective is to design a control system for suppressing the LCOs. For the purpose of control, a single trailing-edge control surface is used. It is assumed that only the pitch angle is measured and the remaining state variables needed for full state feedback are estimated by the designed observer. Then an integral sliding surface is put forward on the estimation space; a new continuous reaching law is proposed to reduce the chattering phenomena. The finite-time reachability of the predesigned sliding surface is proved and guaranteed by the designed sliding mode control law. The sufficient condition for the asymptotic stability of the closed-loop system composed of the sliding mode dynamics and the error dynamical system is derived in terms of linear matrix inequality (LMI). The effectiveness of the proposed strategy is finally demonstrated by simulation results.

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Introduction to Aircraft Aeroelasticity and Loads

Cited by 145 publications

References 0 publications

Impact of the Wing Sweep Angle and Rib Orientation on Wing Structural Response for Un-Tapered Wings

Impact of the Wing Sweep Angle and Rib Orientation on Wing Structural Response for Un-Tapered Wings

Parametric reduced order model approach for rapid dynamic loads prediction

Sliding Mode Observer Controller Design for a Two Dimensional Aeroelastic System with Gust Load

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