Aero-thermo-elastic stability analysis of supersonic variable stiffness sandwich panels using refined layerwise models

Abstract

This work investigates the linear aero-thermo-elastic flutter and buckling stability of supersonic soft core sandwich panels with variable stiffness composite skins using refined layerwise finite element models based on shear deformation theories devoid of thickness stretching, as well as quasi-3D theories with thickness stretching involving Lagrange $z$-expansions. The proposed numerical applications of soft core sandwich panels, with either unidirectional or curvilinear fibres, highlight that the spatially varying fibre orientations, core thickness ratio and applied thermal loads significantly influence the aero-thermo-elastic response behaviour. Additionally, it is concluded that high-order layerwise models with thickness stretching are often crucial to properly capture the complex aeroelastic behaviour of thermally loaded sandwich panels experiencing flutter due to high-order modes. Nonetheless, the layerwise first-order shear deformation model ensures a fair compromise between numerical accuracy and computational efficiency when flutter arises in the first two modes.