Flow angle, temperature and aerodynamic damping on supersonic panel flutter stability boundary

The effects of flow angularity, temperature and aerodynamic damping on supersonic flutter of plates are investigated. The quasisteady first-order piston theory aerodynamics is employed for pressure fluctuation. The von Karman large deflection plate theory is adapted for the aerothermal deflection. Two types of thermal effects: i) plate expansion by uniform temperature, and ii) thermal moment induced by temperature gradient across the plate thickness are considered. An efficient finite element modal formulation and a two-step procedure are presented for the predictions of stability boundaries and nonlinear aerothermal deflection. Results have shown that flow angle has little effect on stability boundaries as compared with temperature for isotropic square plates. But both flow angle and temperature have large influence on stability boundaries for rectangular isotropic and laminated composite plates. The presence of the "ripple" characteristics of stability boundaries for composite plates due to the frequency coalescence of higher modes and the smaller aerodynamic damping is investigated. The stabilization or destabilization induced by variations of flow angle, temperature and aerodynamic damping are discussed.