Stability of a Composite Plate in a High-Enthalpy Gas Flow.

The divergence of a thin elastic plate reinforced by stiff ribs (stringers) with cyclic symmetry is considered, with some approximations. The incoming air flow is assumed to be supersonic, and so the aerodynamic load is described by means of approximate piston theory, for a steady temperature field. In taking account of the composite structure, attention is paid to the configuration of the stiffening ribs; a contact formulation is adopted. The lower critical velocity of the incoming air flow is determined by the first approximation, and its dependence on the number of stiffening ribs is investigated. It is shown numerically that, with increase in the distance between the ribs, the critical rate of divergence approaches its value for a smooth plate. [ABSTRACT FROM AUTHOR]