Aerothermal Modeling and Dynamic Analysis of a Hypersonic Vehicle

Abstract

The effects of aerodynamic heating on the rigid-body and structural dynamics of an air-breathing hypersonic vehicle are addressed. A structural design representative of a skin-stiffened vehicle with a conceptual thermal protection system is devised. The effects of aerodynamic heating on the design is then studied. The resulting temperature distribution through the structure is used to obtain frequencies and mode shapes of the vehicle structural dynamics. In the latter case, the structural dynamics of the vehicle are modelled by a beam whose mass and stiffness characterisitcs give the expected frequencies at ambient, fully loaded conditions, and are computed using the assumed modes method. An analysis of the aircraft’s dynamic modes is then performed. It is shown that the effects of the aerodynamic heating on the aircraft rigid-body poles and zeros is negligible. This is due to the fact that the rigid-body dynamics do not excite the flexible states, and the flexible-body dynamics do not excite the rigid-body states. This paper, however, does not address the effects of the migration of the structural frequencies on controllability due to aeroservoelastic interactions, which can be significant.