Consistent structural linearisation in flexible-body dynamics with large rigid-body motion

Hesse, Henrik; Palacios, Rafael

doi:10.1016/j.compstruc.2012.05.011

Cited by 41 publications

(50 citation statements)

References 35 publications

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“…This will give a compact form of the EoM with large rigid-body motion. The details can be found in Hesse and Palacios 23 and this section will only present the main results.…”

Section: Flexible-body Dynamicsmentioning

confidence: 99%

Consistent Structural Linearization in Flexible Aircraft Dynamics with Large Rigid-Body Motion

2014

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This paper investigates the linearization, using perturbation methods, of the structural deformations in the nonlinear flight dynamic response of aircraft with slender, flexible wings. The starting point is the coupling of a displacement-based geometrically nonlinear flexible-body dynamics formulation with a 3D unsteady vortex lattice method. This is followed by a linearization of the structural degrees of freedom, which are assumed to be small in a body-fixed reference frame. The translations and rotations of that reference frame and their time derivatives, which describe the vehicle flight dynamics, can still be arbitrarily large. The resulting system preserves all couplings between rigid and elastic motions and can be projected

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“…This will give a compact form of the EoM with large rigid-body motion. The details can be found in Hesse and Palacios 23 and this section will only present the main results.…”

Section: Flexible-body Dynamicsmentioning

confidence: 99%

Consistent Structural Linearization in Flexible Aircraft Dynamics with Large Rigid-Body Motion

2014

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“…26 Results are obtained using two-noded displacement-based elements. In a displacement-based formulation, nonlinearities arising from large deformations are cubic terms, as opposed to an intrinsic description where they appear up to second order.…”

Section: B Coupled Finite Element Equations Of Motionmentioning

confidence: 99%

Model Order Reduction for Control Design of Flexible Free-Flying Aircraft

Tantaroudas

Ronch

Badcock

et al. 2015

AIAA Atmospheric Flight Mechanics Conference

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This paper describes a systematic approach to nonlinear model order reduction of freeflying aircraft and the subsequent flight control design. System nonlinearities arise due to large wing deformation and the coupling between flexible and rigid body dynamics. The non-linear flight dynamics equations are linearised and the approach uses information on the eigenspectrum of the resulting coupled system Jacobian matrix and projects it through a series expansion onto a small basis of eigenvectors representative of the full-order dynamics. The testcase is the very flexible wing representative of the Helios wing which was developed by NASA and the aeroelastic solver is validated against other frameworks for gust responses. Nonlinear reduced order models are generated and used for faster parametric worst case gust searches of the full order nonlinear flight dynamic response and are exploited for complex control methodologies such as H∞, H2 and adaptive control designs.

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“…x R := β ;Θ (13) Note that the time-rate-of-change of the bound vortex ring strengths,Γ, is included in the state vector as it is required for the computation of unsteady aerodynamic loads. 23 This set of coupled, linear EoM now form a suitable basis for stability analyses, model reduction, and control syntheses.…”

Section: Iib Linearizationmentioning

confidence: 99%

“…(1) can be found in previous work by one of the authors. 13 Finally, the orientation of the body-fixed reference frame with respect to an inertial frame is parameterized using quaternions, denoted by χ, and computed by solving an extra set of attitude EoM. 14,15 Together with the Eq.…”

Section: Iia Nonlinear Flexible Aircraft Dynamicsmentioning

confidence: 99%

Integrated Flight Dynamics and Aeroelasticity of Flexible Aircraft with Application to Swept Flying Wings

Simpson

Palacios

Goulart

2015

56th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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The dynamics of flexible, swept flying wing (SFW) aircraft are described by a set of nonlinear, multi-disciplinary equations of motion. Aircraft structures are modeled using a geometrically-exact composite beam model which can, in general, capture large dynamic deformations and the interaction between rigid-body and elastic degrees-offreedom. In addition, an implementation of the unsteady vortex-lattice method capable of handling arbitrary kinematics is used to capture the unsteady, three-dimensional flow-field around the aircraft as it deforms. Linearization of this coupled nonlinear description, which can in general be around a nonlinear equilibrium, is performed to yield linear time-invariant state-space models. Verification of aeroelastic stability analyses using these models is carried out. Subsequently, a set of SFW models are developed and the dynamic stability characteristics of these aircraft are investigated for a range of flight velocities and vehicle parameters. Nomenclature

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Consistent structural linearisation in flexible-body dynamics with large rigid-body motion

Cited by 41 publications

References 35 publications

Consistent Structural Linearization in Flexible Aircraft Dynamics with Large Rigid-Body Motion

Consistent Structural Linearization in Flexible Aircraft Dynamics with Large Rigid-Body Motion

Model Order Reduction for Control Design of Flexible Free-Flying Aircraft

Integrated Flight Dynamics and Aeroelasticity of Flexible Aircraft with Application to Swept Flying Wings

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