Free Vibration of Laminated Composite Skew Plates with Delamination around a Quadrilateral Cutout

Abstract

The free vibration analysis of laminated composite skew plates with delamination around a centrally located quadrilateral cutout is carried out based on High-order shear deformation theory (HSDT) in this study. The displacement continuity conditions are introduced to represent the delamination, and the comparison of the delamination formulation based on First-order shear deformation theory (FSDT) and HSDT is carried out in detail. Four-noded shear deformable elements with seven degrees-of-freedom per each node are used in the finite element program developed for this study, and this computer program used an oblique coordinate system to analyze the skew plates. To validate the accuracy of the developed finite element program, validation study for various cases is carried out. And the results are in good agreement with those of other preceding investigations. The new results in this study mainly show the effect which the interactions between the skew angle and other various parameters, for example, cutout size, delamination size, location of delamination, side-to-thickness ratio, boundary conditions, number of layers, etc. have influence on the free vibration of laminated composite skew plates.