| The Tiltrotors have tiltrotor planted on the fixed wing tip and can alter the flight mode betweenthe helicopter mode and the propeller-driven aircraft mode by pivoting the tiltrotor. The Tiltrotorscombine the advantages of helicopter and fixed wing aircraft and have a broad applied prospects, butthe Tiltrotors have more complicated aeroelastic couplings between the rotor and the fixed wing thancommon helicopters and the propeller-driven aircraft. It is very important to analyze the aeroelasticstability of the Tiltrotors.This thesis mainly focuses on the aeroelastic stability of tiltrotor aircraft with the freedom degreeof the tilting hinge considered. This thesis consists of two mainly parts. In the first part, based onHamilton’s principle and the multi-body method, an aeroelastic dynamical model of semi-spantiltrotor aircraft is developed with considerations of complex couplings between the rotor and thewing due to the nonlinear characteristics coming from the complicated aerodynamic and inertial forceas well as the complicated structures. The influence of the freedom degree of the tilting hinge is fullytaken into account in this thesis. In the second part, aeroelastic stability of the model developed in thefirst part is analyzed. The parameter investigations include: the tilting hinge pitch stiffness, the tiltinghinge yaw stiffness, the sweep angle of the wing, the offset of the tilting hinge, the rotor speed, therotor blade pitch/flap coupling, the rotor flap stiffness, the rotor mast height. Some importantconclusions and disciplines have been obtained which can be used as reference in the design of thetiltrotor aircraft. |
