Free Vibration of Skew Fiber-reinforced Composite and Sandwich Laminates using a Shear Deformable Finite Element Model

A simple C^o isoparametric finite element model, based on a higher-order shear deformation theory is presented for the free vibration analysis of isotropic, orthotropic, and layered anisotropic composite and sandwich skew laminates. This theory incorporates a realistic nonlinear variation of displacements through the laminate thickness, and eliminates the use of shear correction coefficients. The boundary conditions on the skew edges are imposed through the suitable transformation of element matrices. The accuracy of the present model is demonstrated by comparing with alternative solutions available in the literature. Extensive numerical results are presented for natural frequencies of cross-ply and angle-ply skew laminates with various lamination parameters, skew angles, boundary conditions, and width-to-thickness ratios. New results on skew sandwiches are obtained for different lamination parameters and skew angles.