Nonlinear Flight Dynamics of a Flexible Aircraft Subjected to Aeroelastic and Gust Loads

Abstract

In this paper, nonlinear flight dynamics of a flexible aircraft under aeroelastic and gust loads is presented. Hybrid state governing equations that incorporate both aircraft rigid-body motions and elastic deformations are utilized. The aircraft wings perform as classical beams, and the structural model, which incorporates bending–torsion flexibility, is used. In addition, quasi-steady and Peter’s unsteady aerodynamic pressure loadings are considered and modified to take the gust velocity components into account. The distributed parameters representing elastic deformations of flexible components are discretized by using Galerkin’s method. Three different excitations are considered for nonlinear simulation: aileron, elevator, and vertical/pitch components of Dryden gust model. Time responses of the rigid vehicle and elastic aircraft with quasi-steady and unsteady aeroelastic model are presented, and differences are highlighted.