Improved Meshfree Moving-Kriging Formulation for Free Vibration Analysis of FGM-FGCNTRC Sandwich Shells

An improved meshfree moving-Kriging (MK) formulation for free vibration analysis of functionally graded material-functionally graded carbon nanotube-reinforced composite (FGM-FGCNTRC) sandwich shells is first proposed in this article. The proposed sandwich structure consists of skins of FGM layers and an FGCNTRC core. This structure possesses all the advantages of FGM and FGCNTRC, including high electrical or thermal insulating properties, high fatigue resistance, good corrosion resistance, high stiffness, low density, high strength, and high aspect ratios. Such sandwich structures can be used to replace conventional FGM structures. The present formulation has been established by using an improved meshfree MK method and the first-order shear deformation shell theory (FSDT). The effective material characteristics of the FGM-skin layers and the FGCNTRC core were calculated using the rule of mixture. Key parameters and factors such as the thickness-to-radius ratio, the length-to-radius ratio, layer-thickness ratios, CNT distributions, the volume fraction of CNTs, the power-law index, and various boundary conditions were rigorously investigated. A nonlinear CNT distribution that we term FG-nX is first proposed in this work, and many new results of FGM-FGCNTRC sandwich shells have been provided.