Pure global buckling and vibration in laminates with arbitrary shape cut off regions

The pure global buckling and vibration of four sides simply supported as well as clamped anisotropic laminates having an arbitrary shape cut off region that is symmetric with respect to mid-plane have been studied by treating the remaining cut off regions as uniform plates with reduced stiffness. The reduced variation of stiffness of the plate is represented by Fourier series. Computational solutions of the energy principle for the Ritz method in a plate having arbitrary shape of typical cut off regions under biaxial compressive loads are obtained. Some numerical results for the pure global buckling load prediction due to its reduced flexural stiffness for the circular cut off regions and elliptical cut off regions are presented. We find the normalized pure global buckling load ratio decreases as the cut off regions size increases, and the non-dimensional fundamental frequency value decreases as the cut off regions size increases.