Model validation of an aeroelastically-tailored forward swept wing using fibre-optical strain measurements

Abstract

The Institute of Aeroelasticity of the German Aerospace Center (DLR) in Göttingen has analysed means to passively minimise gust load encounters within the DLR project ALLEGRA. One goal was to develop and test a highly flexible forward-swept wind tunnel model which is aeroelastically optimised for maximum tip deflection while constraining the tip twist. Stiffness optimisation tools offer the possibility to design wings with very specific aeroelastic constraints. From the optimised stiffness distribution a feasible stacking sequence needs to be derived to reach the full potential of the stiffness optimisation process. After manufacturing, the wind tunnel model needs to be validated thoroughly. Here, a two-step validation process will be shown. First, static tests obtaining deflection and strain measurements are utilised to adjust the finite element model by a computational model updating (CMU) approach [1-3]. Second, experimental eigenfrequencies and strain shapes are used to check the validity of the updated model.