Structural and Aerodynamic Models in Nonlinear Flight Dynamics of Very Flexible Aircraft

Abstract

An evaluation of computational models is carried out for flight dynamics simulations on low-speed aircraft with very-flexible high-aspect ratio wings. Structural dynamic models include displacement-based, strain-based, and intrinsic (first-order) geometrically-nonlinear composite beams, while thin-strip and vortex lattice methods are considered for the unsteady aerodynamics. It is first shown that all different beam finite element models (previously derived in the literature from different assumptions) can be consistently obtained from a single set of equations. This approach has been used to expand existing strain-based models to include shear effects. Comparisons are made in terms of numerical efficiency and simplicity of integration in flexible aircraft flight dynamics studies. On the structural modeling, it was found that intrinsic solutions can be several times faster than conventional ones for aircraft-type geometries. For the aerodynamic modeling, thin-strip models based on indicial airfoil response are found to perform well in situations dominated by small amplitude dynamics around large quasi-static wing deflections, while large-amplitude wing dynamics require three-dimensional descriptions (e.g. vortex lattice)

Optimal Rolling Maneuvers with Very Flexible Wings

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Dynamic Load Alleviation in Wake Vortex Encounters

“…The various modules in SHARP have been verified for this same platform in previous publications. 22,27,28,40,41,60 The characteristics of the vehicle will be briefly defined in Subsection IV.A. The aeroelastic/flight-dynamic simulation model is then exercised in Section IV.B to explore the effect of wake vortex strength, different encounter angles and displacement on the vehicle flight dynamic response.…”

Robust Aeroelastic Control of Very Flexible Wings using Intrinsic Models

“…Their definition in terms of beam displacements and rotations can be found, for example, in the work by Palacios. 20 The material constants in the equation are the cross-sectional mass, M , and flexibility (or compliance), C, matrices, which can be obtained from a structural homogenisation process. 21 They are full symmetric matrices that may vary with the arc length, s. Finally, the matrix E includes the effect of the initial strain γ 0 and curvature k 0 by…”

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