Nonlinear Flutter of Cylindrical Panels Under Yawed Supersonic Flow Using Finite Elements

Abstract

In the extensive published literature on panel flutter, large number of papers were dedicated to investigate flat plates in the supersonic flow regime. Very few authors have extended their work to flutter of curved panels. The curved geometry generates a pre-flutter behavior due to a static aerodynamic load (SAL) over the panel resulting in the existence of a static deflection. The purpose of this paper is to provide new insights in the subject of flutter of curved panels. A finite element frequency domain method is developed and presented to predict the pre-flutter behavior and the flutter onset of curved panels. The firstorder shear deformation theory, the Marguerre curved plate theory, the von Karman large deflection theory, and the quasi-steady first-order piston theory appended with SAL are used in the formulation. The principle of virtual work is applied to develop the equations of motion of the fluttering system in structural node degrees of freedom (DOF). The NewtonRaphson iteration method is used to determine the panel deflection under the SAL, and an eigen-value solution is employed for the determination of the flutter critical dynamic pressure at different panel height-rises. Pre-flutter static deflection shape, flutter coalescence frequency, and damping rate of various cylindrical panels are thoroughly investigated. The main results revealed that the pre-flutter static response of curved panels is fundamentally different from the one associated with flat plates. It is shown that curvature has a detrimental effect for 2-D cylindrical panels, and beneficial for 3-D at an optimum heightrise.