Nonlinear Flutter Suppression and Thermal Buckling Elimination for Composite Lattice Sandwich Panels

Abstract

A mechanism is proposed to suppress the nonlinear flutter and thermal buckling of composite lattice sandwich panels with tetrahedral truss core in supersonic airflow by means of the Winkler–Pasternak elastic foundation. The strain-displacement relations are evaluated according to the von Kármán large deflection and first-order shear deformation theories. The aerodynamic pressure acting on the sandwich panel is formulated by the supersonic piston theory. The nonlinear equations of motion of the structure are established by Hamilton’s principle in conjunction with the assumed mode method. By using the Winkler–Pasternak elastic foundation, an effective method for eliminating the nonlinear thermal buckling of the structure is presented. The natural frequencies of the sandwich panels are validated through comparing with the published results. The parametric investigations on the shearing layer and Winkler parameters are conducted. The influences of several parameters, including ply angle of laminated face sheets, and radius and material properties of the trusses on the nonlinear flutter, and thermal buckling behaviors are investigated. The numerical results attest that the nonlinear thermal buckling effect can be completely eliminated, and the nonlinear flutter of the composite lattice sandwich panels can be effectively suppressed by adjusting the elastic foundation parameters.