Nonlinear Thermal Flutter Of Functionally Graded Panels Under A Supersonic Flow

摘要

Thermal flutter characteristics of functionally graded (FG) ceramic/metal panels under the thermal and aerodynamic loads are investigated. The volume fractions of the constitutive materials are determined by a simple power-law distribution, and material properties are assumed to be a linear rule of mixture. The panels are considered as rectangular plates based on the first-order shear deformation theory, and the von Karman strain-displacement relations are used to account for the geometric nonlinearity. The first-order piston theory is adopted to represent aerodynamic pressures induced by supersonic airflows. The principle of virtual work is applied to derive equations of motion, and a finite element method is used to obtain numerical solutions. The Newton-Raphson method is adopted to obtain approximate solutions of the nonlinear governing equations. Flutter boundaries are defined by eigenvalue analysis, and the Guyan reduction is used to reduce degree of freedom. Flutter motions of FG panels are investigated using the Newmark method. The effects of volume fraction distributions, boundary conditions, temperature changes and aerodynamic pressures on panel flutter characteristics are analyzed in detail.