Influence of Temperature and Moisture on Free Vibration Behavior of Skew Laminated Composite Sandwich Panels with CNTRC Core

Abstract

This paper presents the influence of temperature and moisture on the free vibration characteristics of skew laminated composite sandwich (SLCS) panels. The face sheets of the panels are made of graphite–epoxy composite, while the core consists of carbon nanotube-reinforced composite. The coupled hygro-elastic and thermo-elastic relations for the SLCS shells/panels are formulated using first-order shear deformation theory. The nonmechanical stiffness matrices are represented by the initial stress stiffness matrix developed using nonlinear strain–displacement relations. The temperature and moisture-dependent material properties are considered to analyze the laminated composite sandwich spherical, hyperbolic, ellipsoid, cylindrical Shells, and flat plates. Several numerical examples are comprehensively studied to establish the influence of temperature, moisture, the volume fraction of carbon nanotubes in the core material, functional gradation types, skew angle, and edge constraints on the vibration responses of SLCS shells. Further exploration is devoted to studying the combined effect of moisture, temperature, and the geometrical parameters such as length to width ratio, length to thickness ratio, radius-to-length ratio, and the core thickness to face sheet thickness ratios on the natural frequency of the skew laminated composite sandwich panels.