Aeroelastic analysis of a 3D wing structure with a flexible trailing edge

Aeroelastic analysis of a 3D wing structure with a flexible trailing edge

Lonsain, J.

De Breuker, R. (mentor)
Sodja, J. (mentor)

Aerospace Engineering

Aerospace Structures and Materials

2017-03-27

Aeroelastic analyses traditionally consider the airfoil of a wing to remain rigid, only allowing deformation in the span-wise direction of the wing. Recent investigations have shown the benefits of adding chord-wise flexibility in the trailing edge of a wing, however so far only two-dimensional studies have been carried out. Therefore, the investigation presented here determines whether chord-wise flexibility in the trailing edge improves aeroelastic behaviour for three-dimensional wing structures as well. To determine whether chord-wise flexibility improves the aeroelastic characteristics, a dynamic aeroelastic state-space model is built to compute the flow velocity at which the wing structure becomes instable and a closely coupled static model to compute the steady aerodynamic loads. Linear Timoshenko beam finite elements are used to represent the wing-box structure and are part of the existing aeroelastic framework PROTEUS, which is developed at the TU Delft. Linear flat shell elements are used to model the structure of the flexible trailing edge and rigid links couple these elements to the wing-box structure. The aerodynamic model in PROTEUS is modified in such a way that individual panel forces are extracted and trailing edge deformation can be transferred to these panels. By varying the thickness of a quasi-isotropic carbon fibre laminate in the trailing edge, its flexibility is managed. It was found that increasing the flexibility of the trailing edge increases the flutter speed of the wing in a similar manner as with a 2D typical section. A difference with a 2D typical section is that in the region of plate flutter, mode jumps occur due to span-wise deflection of the wing-box. If only part of the wing in span-wise direction is equipped with a flexible trailing edge, the flutter speed can be increased more effectively by positioning it towards the tip of the wing. The downside of increased trailing edge flexibility is the reduction in steady lift generated by such a wing.

Aeroelasticity
Chord-wise flexibility
Finite element model
Plate elements
Vortex-lattice method
State-space system

http://resolver.tudelft.nl/uuid:0e795e6d-ddc8-4710-b92a-adf1ee3cbdd7

Student theses

master thesis

(c) 2017 Lonsain, J.