Development of a Computational Framework for Aeroelasticity of Geometrically Nonlinear Structures

Abstract

High Altitude Long Endurance (HALE) configurations have gained much popularity in the recent past. Although, HALE aircraft enable efficient and environmental-friendly flying, they necessitate a large Aspect-Ratio wing. These slender structures are prone to large, non-linear deformations which further increase the unsteady nature of aerodynamic flow that can detrimentally impact the structure. In the light of this trend towards an efficient aviation industry of tomorrow, Airbus Innovations UK has ventured into the development of a folding wing tip concept whose benefits are two-fold. First, is the ability to increase span during flight, thereby reducing the induced drag. The folding capability also ensures entry gate requirements at airports. Secondly, the folding mechanism presents load alleviation capabilities with appropriate hinge setup. Alleviation of loads on lifting surfaces directly translates to reduction of the Wing Root Bending Moment (WRBM), which means a reduction of weight. Thus, a further improvement in efficiency of flight. In this work, a nonlinear aeroelastic solver is developed. The proposed partitioned framework couples the industry standard commercial software package MSC Nastran, a structural solver to the Unsteady Vortex Lattice Method (UVLM), an aerodynamic solver. The UVLM module developed, exhibits both static and dynamic capabilities. Three wake models are incorporated. Horse-shoe wake is employed for static simulations and convective wake procedures are available for transient dynamic simulations. The independent modular solvers are coupled using Radial Basis Functions (RBFs) and Nearest Neighbour (NN) approaches. This framework enables the solver to capture the combined effects of structural nonlinearities and unsteady flows. The proposed solver is then verified and validated for two different test cases: NASA CRM Wing and Pazy Wing. Experimental validation is carried out using existing results from related work. The solver is then used to evaluate the “AlbatrossOne”, a hinged wingtips concept by Airbus Innovations UK. Both static and dynamic responses are analysed for load alleviation capabilities.