Parametric instability of thick doubly curved CNT reinforced composite sandwich panels under in-plane periodic loads using higher-order shear deformation theory

This paper focuses on the problem of parametrically excited doubly curved sandwich shells with carbon nanotubes reinforced composite (CNTRC) facesheets subjected to in-plane periodic load. The panels consist of cylindrical and spherical shells modeled using QUAD-8 element which was developed using higher-order shear flexible theory. The formulation considers the secondary effects such as the influence of in-plane and rotary inertia terms, and the aerodynamic pressure when the panel is exposed to air flow. The governing equations developed are solved based on eigenvalue approach. The limits of the principal instability zone predicted here are graphically represented using excitation frequencies against the load amplitudes. The results of this study are tested against the available solutions in the literature. A detailed study considering various design parameters including structural theories on the dynamic instability boundaries and its associated origin of instability regions is conducted. These parameters include the CNT volume content, thermal environment, aspect ratio, thickness ratio of core and facesheet, and radius of curvature.