Frequency-dependent forced vibration analysis of nanocomposite sandwich plate under thermo-mechanical loads

In this paper, the effect of loading frequency on the dynamic behavior of nanocomposite sandwich plates under periodic thermo-mechanical loadings has been investigated. The utilized sandwich plates are made of an isotropic polymer material and two symmetric face sheets reinforced by functionally graded (FG) distributions of carbon nanotube (CNT) agglomerations. In addition to periodic mechanical loads, these structures are also subjected to thermal gradient loads. Steady state response of the plates under thermal gradient load was assumed like a pre-stress for dynamic equations in conducting timeline vibrations of the structure. The material properties of polymeric matrix and CNTs were assumed to be temperature-dependent and the overall material properties of nanocomposites were estimated using Eshelby-Mori-Tanaka's approach. In order to achieve accurate results, a mesh-free method based on higher order shear deformation theory (HSDT) was utilized. The effects of mechanical loading frequency and thermal gradient load as well as CNTs cluster characterizations, essential boundary conditions and elastic foundation on forced vibration, resonance and phenomenon of beats behaviors were investigated. It was observed that thermal gradient loads and the formation of CNT agglomerations have significant effects on the amplitudes of vibrations in nanocomposite sandwich plates.