Modal and aeroelastic analysis of trapezoidal corrugated-core sandwich panels in supersonic flow

Corrugated-core sandwich panels have a great potential in the application to acreage thermal protection system of aerospace vehicles. However, due to their structural complexity, it takes high computational cost to conduct modal analysis with detailed 3D finite element models and the aeroelastic behaviors of these sandwich structures have not been fully investigated. In this paper, an analytical model of a trapezoidal corrugated-core sandwich panel using homogenization technique and layerwise theory is presented for modal and aeroelastic analysis. The trapezoidal corrugated core is homogenized as an equivalent orthotropic layer based on an energy approach and the overall sandwich panel is treated as a three-layer continuum. The proposed layerwise theory which is developed for a sandwich plate, assumes higher-order displacement field for the core layer and first-order displacement field for the top and bottom layers. The unsteady aerodynamic pressure is evaluated by the supersonic Piston theory. An eight-noded C-0 isoparametric element with 13 degrees of freedom per node is used for finite element method. The accuracy and reliability of the present method are verified by comparing natural frequencies and mode shapes as well as flutter speeds with those obtained from commercial software. Parametric studies concerning different boundary conditions and parametric variables are also conducted. It is shown that the proposed method has sufficient accuracy and requires less computational effort, providing a theoretical basis for the utilization of the trapezoidal corrugated-core sandwich panel in aircraft designing.