Session: 03-07: Dynamics and Control of Morphing Wing

Paper Number: 93736

93736 - Analysis of Aeroelastic Deformation in Reconfigurable Wings 

The low cost and low risk nature of small unmanned aerial vehicles has enabled the testing of various types of active structures which may enable significant performance enhancements including increased range and endurance, as well as optimization for varying phases of flight. These active structures may lead to changes in various physical aspects of the vehicle including variable wing camber, twist, sweep, and span. While it is necessary to predict the impact of these active structures on the aerodynamic and control properties of these aerial vehicles, it is also vital to understand the inverse relationships of how aerodynamic and controls will impact the elastic deformation of these active structures. To that end, the uncoupled static aeroelastic analysis method has been augmented to enable the analysis of active wings via the inclusion of a reconfiguration parameter. The uncoupled static aeroelastic analysis method enables rapid analysis of the aeroelastic behavior of an aerial body through the use of surrogate modeling. This method has been shown to yield accurate results when compared to both experimental results and coupled aeroelastic analyses while significantly reducing the cost (physical and computational, respectively). In the current study, a representative small unmanned aerial vehicle wing is studied with a variable wing-span. Consideration of constant, level flight without requiring changes to the angle of attack leads to an inverse variation in flight velocity as wingspan increases. The analysis of such a wing with variable wing-span while considering variable flight velocity is performed for a wing with a rectangular planform and constant cambered airfoil shape, wherein the wingspan varies from 0.6 m – 0.8 m. The wingspan varies utilizing a telescoping outer wing segment. The skin consists of an elastomeric composite capable of large span-wise deformations with a low modulus, while maintaining a high modulus in the chord-wise direction, enabling a single continuous skin to sustain the aerodynamic loads for all wingspans. Results show that the inter-spar skin displacement reduces as the wingspan increases due to the addition of span-wise strain. Furthermore drag also reduces as wingspan increases due to a decrease in velocity in order to maintain constant lift. However these reductions are realized at the cost of an increased wing tip displacement as the wingspan is increased.

Presenting Author: Francis Phillips DEVCOM Army Research Laboratory