Flutter Characteristics of a Joined-Wing Unmanned Aerial Vehicle with Variable Dihedral Angles

Abstract

A parametrized aeroelastic model is built to study the flutter characteristics of a new joined-wing unmanned aerial vehicle (UAV) with variable dihedral angles. First, the substructure modal synthesis is introduced to construct the structural finite element model of the joined-wing UAV according to the connection relations between adjacent wing segments. Second, the doublet-lattice method is introduced to obtain the aerodynamic characteristics of each airfoil in subsonic flow, taking into account the interactions between each airfoil. After that, a parametrized aeroelastic model with variable inclination angles is established, and the p-k method is used for flutter calculations. The results show that the joined-wing UAV has wide ranges of flutter velocities and flutter frequencies, which show a nonlinear growth trend with the increase of the tail inclination angle owing to the flutter mode transitions. In addition, the forward sweep angles of the joined wing and the rigidity of the tail links both have significant impacts on the flutter characteristics of the joined-wing UAV.