The Effect of Folding Wingtips on the Flight Dynamics of an Aircraft with Elastic Wings

D Balatti, H Haddad Khodaparast, MI Friswell, M Manolesos (Swansea University) & MR Amoozgar (University of Huddersfield)

IMechE Part G: Journal of Aerospace Engineering, Vol. 236, No. 2, February 2022, pp. 219-237

Abstract

In recent years, the development of lighter and more efficient transport aircraft has led to an increased focus on gust load alleviation. A recent strategy is based on the use of folding wingtip devices that increase the aspect ratio and therefore improve the aircraft performance. Moreover, numerical studies have suggested such a folding wingtip solution may incorporate spring devices in order to provide additional gust load alleviation ability in flight. It has been shown that wingtip mass, stiffness connection and hinge orientation are key parameters to avoid flutter and achieve load alleviation during gusts. The objective of this work is to show the effects of aeroelastic hinged wingtip on the problem of worst-gust case prediction and the parameterisation and optimization of such a model for this particular problem, i.e. worst-case gust load prediction. In this paper, a simplified aeroelastic model of full symmetric aircraft with rigid movable wingtips is developed. The effects of hinge position, orientation and spring stiffness are considered in order to evaluate the performance of this technique for gust load alleviation. In addition, the longitudinal flight dynamics of a rigid aircraft with an elastic wing and folding wingtips is studied. Multi-objective optimizations are performed using a Genetic Algorithm to exploit the optimal combinations of the wingtip parameters that minimize the gust response for the whole flight envelope while keeping flutter speed within the safety margin. Two strategies to increase flutter speed based on the modification of the wingtip parameters are presented.

Paper Availability

This material has been published in the IMechE Part G: Journal of Aerospace Engineering, Vol. 236, No. 2, February 2022, pp. 219-237. The paper is published as open access.


Link to paper using doi: 10.1177/09544100211010915

IMechE Part G: Journal of Aerospace Engineering