Combined active and passive loads alleviation through aeroelastic tailoring and control surface/control system optimization

This paper presents the trade-off between active loads alleviation through trailing edge flaps and passive loads alleviation through bending-twisting coupling. Both loads alleviation methods have conflicting requirements for optimal effectiveness. Therefore it is of interest to trade them off in an optimisation context. A dedicated aeroservoelastic model is developed that quickly can assess gust loads in the presence of flaps and bending-twisting coupling. This model is based on a linear Euler beam closely coupled to a Theodorsen unsteady aerodynamics model that is converted to time domain using the indicial functions method of Leishman. It is demonstrated in this paper that a combination of active and passive loads alleviation outperforms separate loads alleviation methods.