Free vibration response of smart sandwich plates with porous CNT-reinforced and piezoelectric layers

Abstract

This work concerns with the free vibration behaviors of a multifunctional smart sandwich plate (MSSP) using an advanced and reliable method. The layers of the MSSP includes two thin active piezoceramic faces which integrate a passive multifunctional lightweight core. The passive layer is enhanced with carbon nanotubes (CNTs) and lightened by embedding voids. Moreover, using the concept of functionally graded (FG) materials, both CNTs and voids are assumed to be distributed in FG patterns. In addition, the common drawback in such nanocomposites i.e., the formation of CNT agglomeration is distinguished by utilizing Eshelby-Mori-Tanaka (EMT)'s procedure. To obtain the governing equation of free vibration analysis, Reddy's third order shear deformation theory (TSDT) is employed. This equation has been handled by developing a weak form mesh-free solution with the shape functions of moving least squares (MLSs). The effects of lightening with voids, enhancing with nanofillers and its agglomerations, geometrical dimensions, and electro-mechanical boundary conditions on the natural frequency of MSSPs have been characterized. The results indicate that because of forming CNT agglomerations, the increase of the natural frequencies of MSSPs by adding CNTs is restricted. In addition, embedding voids inside the core results in MSSPs with higher natural frequencies in most cases.