Stability analysis of multifunctional smart sandwich plates with graphene nanocomposite and porous layers

The application of piezoelectric layers on the outer surfaces of lightweight passive sandwich plates can offer multifunctional smart sandwich plates (MFSSPs). This paper proposes a new MFSSP and studies its critical stability mechanical loads and temperature changes. The smart plate is proposed to include a multifunctional passive sandwich plate integrated with two active piezoelectric layers. The lightweight sandwich plate has a polymeric porous core and two randomly oriented graphene/polymer nanocomposite layers. Different profiles are considered for graphene and porosity distributions in nanocomposite and core layers, respectively. A modified Halpin-Tsai' approach with efficiency parameters is employed to estimate the material properties of polymer/graphene layers. Reddy's third order shear deformation theory (TSDT) of plates is selected to estimate displacement field and obtain the governing stability equations of the proposed MFSSP. Then, a mesh-free method is developed to solve the obtained mechanical and thermal stability equations. The effect of MFSSP's parameters, including porosity and graphene characteristics, on the stability responses have been studied. The results disclose that the addition of graphene significantly improves the mechanical stability responses of MFSSPs. Furthermore, embedding more pores in core layer can improve the thermal stability of MFSSPs without a considerable reduction in their mechanical stability responses.