Frequency Domain Method for Flutter of Curved Panels Under Yawed Supersonic Flow at Elevated Temperatures

Abstract

A finite element frequency domain method is developed and presented to predict the preflutter behavior and the flutter onset of curved pa nels subjected simultaneously to aerodynamic and thermal loading. The Marguerre plate theory, the von Karman large deflection theory, the quasi-steady first-order pis ton theory and Quasi-static thermoelasticity are used in the formulation. The principle of virtual work is applied to develop the equations of motion of the fluttering s ystem in structural degrees of freedom. The Newton-Raphson method is used to determine the panel deflection under the Static Thermo-Aerodynamic Loading (STAL), and the Eigen-value solution is employed for the prediction of flutter critical dynamic pressure for curved panels of different height-rises. Flutter coalescence frequencies, and damping rates of the fluttering curved system are thoroughly investigated for 3D curved panels under increasing dynamic pressure and uniform or linearly varying temperature gradient loading. Critical buckling temperatures are found out for 3D flat plates of same geometry e xcept the curvature, and used to define non-dimensionalized thermal loading. The results s howed that the flutter dynamic behaviors alter significantly when temperature effe cts come into the picture.