Free Vibration of Polar Orthotropic Laminated Circular and Annular Plates

The paper deals with the free vibration analysis of polar orthotropic laminated circular and annular plates. The first order shear deformation theory and the variational energy method are employed in the mathematical formulation, and an eight-node isoparametric finite element model in polar co-ordinates is used for finding natural frequencies. The effects of material property, stacking sequence, hole size, plate thickness to radius ratio and boundary conditions on natural frequencies are investigated. Numerical results are shown in tabular and graphical forms, and some comparisons with existing results are made for the validation purpose.