摘要

In an air-breathing hypersonic vehicle, the integrated airframe/scramjet engine configuration, slender body profile and light structural design lead to strong coupling among aerodynamics, propulsion and structural dynamics, which brings great challenges to aircraft modeling and control system design. To investigate the principle of coupling and the dynamic characteristics of coupling, this study develops a model for the longitudinal dynamics of the rigid body/elastic body coupling of air-breathing hypersonic vehicles by treating a vehicle as two cantilever beams clamped at the center of mass. It considers the coupling effects of elasticity, non-steady aerodynamic forces and the scramjet engine. The equations for the motion of disturbances of the coupling model are derived by the variation method. Hypersonic non steady aerodynamic forces are calculated using Newton Impact Theory. Engine performance is analyzed based on isentropic flow theory and Rayleigh flow theory including heating. The influences of centrifugal forces and gravitation are also introduced. The simulation results indicate that the eigenvalues of the vehicle system change significantly if the elastic coupling effect is considered and that the introduction of centrifugal forces affects the altitude and long period modes. Finally, the dynamic characteristics of aerodynamics/propulsion/elasticity coupling are analyzed comprehensively.