Refined Plate Theory for Critical Buckling Analysis of FG Sandwich Nanoplates Considering Neutral Surface Concept and Piezoelectric Surface Effects

Abstract

The nonlocal quasi-3D static stability analysis of the sandwich simply ‎supported nanoplates embedded in an orthotropic Pasternak foundation placed in an electrical environment by considering the surface effects based on a five-variable refined plate theory by taking into account the stretching effects is investigated in the current study. The core of the structure is functionally graded along its thickness using a power law model. The concept of neutral surface position is applied to achieve symmetry in the distribution of material properties across the thickness. The piezoelectric face sheets are actuators and sensors for the functionally graded layer based on the surface piezoelasticity theory. According to the nonlocal strain ‎gradient theory, the higher-order shear deformation theory is utilized to develop the linear equilibrium equations of ‎motion based on the principle of minimum potential energy.‎ Eventually, ‎a Navier-type solution is applied to obtain the analytical results of a three-layered nano-plate ‎subjected to the electric field. ‎Evaluation of the accuracy and efficiency of the current approach demonstrates a good agreement between the obtained results from this model and those published in the reviewed literature. Eventually, a comprehensive study is conducted to examine the influences of various parameters on the critical buckling load of the functionally graded sandwich structure in detail. Numerical results indicate significant influences of residual surface stress and neutral surface position on the critical buckling load, particularly in thick nanoplates. These findings are expected to aid in designing micro/nano-electro-mechanical system components based on smart nanostructures.