A critical evaluation of the Hénon's technique for solving aeroelastic problems with control surface friction and freeplay

Abstract

It is known that the presence of nonlinearities in aeroelastic systems can change the dynamic of flight. Particularly, freeplay and friction in control surfaces can modify the aircraft stability, even resulting in flight envelope limitations. According to the literature, the inclusion of freeplay requires time domain analysis using the Hénon's technique to avoid numerical errors. However, a critical evaluation of this issue considering the simultaneous effect of friction and asymmetric freeplay have been neglected by the scientific community, although they are typical nonlinearities in aeroelastic systems. In this context, this proposal includes an analytical and numerical study of the time domain aeroelastic responses for an one and a three degrees of freedom airfoil considering the effect of hinge line friction and asymmetric control surface freeplay. In particular, the focus is to investigate the viability of using the Hénon's approach in comparison with a classical Runge-Kutta algorithm when these two nonlinearities are considered. (AU)