Nonlinear Flutter Analysis of Composite Panels in Thermal Environment

Abstract

Composite materials have been widely applied to the structure of high-speed flight vehicles due to their excellent performance. In hypersonic flight, the buckling and nonlinear flutter will occur in the composite panel on account of the combined action of unsteady aerodynamic load and thermal effect. In this paper, the nonlinear finite element model of the composite thin-walled structure considering thermal effect is established, and combined with the second-order loose coupling algorithm of dynamic-structure, the nonlinear aeroelastic response of composite panels at Ma∞=5 is analyzed. The influence of the direction of composite layer and tempera-ture load on the flutter characteristics of the panel is discussed. The results show that the flutter of the panel is affected by temperature load, layer direction and free stream dynamic pressure. The flutter critical dynamic pressure of the angle-ply panel is higher than that of the cross-ply panel (the increment is more than 55%). With the increase of temperature, the flutter pressure of the panels will decrease, and the maximum reduction is about 80%. While thermal buckling occurs, the flutter dynamic pressure will increase slowly. When the temperature exceeds the critical buckling temperature of the structure, the panel will have static buckling positions under subcritical conditions, and the buckling equilibrium position changes with different dynamic pressures.

Keywords

• |hypersonic velocity|panel flutter|composite materials|thermal effect|nonlinear aeroelasticity|thermal buckling|vehicle