Predicting the In-Flight Shape of an Aircraft Wing

Accurate prediction of the in-flight shape of aircraft wings is essential for achieving optimal aerodynamic performance. Modern aircraft wings are longer, thinner resulting in a more elastic structure. They are constructed from composite materials which can introduce additional uncertainties when it comes to numerical modelling and simulation. While conventional finite element model updating techniques are widely used to tune numerical models using experimental data, in order to produce better predictions, the tuning of the structure to achieve specific targets remains a challenge. This paper introduces an inverse model updating approach, based on the sensitivity-based method, to fine-tune the physical structure rather than the numerical model. The methodology demonstrated using an experimental rig that represents a discretised aircraft wing box with controllable structural stiffness at three locations, making it possible to physically tune the underlying stiffness matrix directly. In-flight shape of the rig was achieved by utilising a compressed air system in order to replicate the loading exerted on real wings by the aerodynamic pressure during cruise. Static tip displacement value and modal parameters were set as targets that the physical model had to meet following the updating process. The targets were set by finite element model. Two cases are presented in the paper, one having a larger discrepancy than the other. In both cases the method improved the physical structure behaviour and reduced the error between the experimentally measured and target parameters.