Abstract:
The pursuit of aerodynamic efficiency and the advances in materials technology, particularly in composite material, has contributed to shifting the paradigm of
wing design to high aspect ratio wings. Increasing the span, for decreasing drag,
and using composite lightweight materials make the new wing very flexible and
prone to nonlinear dynamic behaviour. With nonlinearities, increasing challenges
arise for the identification and modelling of the wing. These challenges cannot
be overlooked for flexible structures as these models are critical for the prediction
of aeroelastic phenomena. Hence, it is fundamental to expand the knowledge
of the behaviour of these structures through the identification and modelling of
sample flexible wing models. In this work, a series of methods and approaches
are proposed and employed for the identification and modelling of a flexible wing.
First, a system identification technique in the frequency domain, the Loewner
Framework, is applied for modal parameters extraction in mechanical systems
for structural health monitoring. This new technique, with a linear reduced order
model, is used to characterise the flutter behaviour of a flexible wing. The results
are compared to similar techniques. A thorough experimental campaign is run on
a flexible wing model to characterise its nonlinear behaviour and the underlying
linear system. In particular, nonlinearities are detected, identified and quantified.
Then, a meta-model technique based on Kriging, the refined Efficient Global Optimisation, is proposed for finite element model updating. First, the technique is
used for damage detection in benchmark structures, then, it is employed for the
validation of component-based strategies for model updating of a flexible wing.