In this paper, generalized differential quadrature method (GDQM) is employed and vibration analysis of annular circular and sector  plates with non-uniform thickness is investigated numerically. Natural frequencies and corresponding vibration modes are obtained for various boundary conditions. Accuracy and efficiency of the presented GDQM are tested against previous results for free vibration analysis of uniform ones and numerical results are proposed for free vibration analysis of annular circular plates with non-uniform thickness in three cases of linear variable thickness, parabolic variable thickness and exponential variable thickness and also for sector plates with linear variation in thickness. Meanwhile, effects of radii ratio, sector angle and variation of the thickness on the natural frequencies are investigated.

generalized differential quadrature method, free vibration, annular circular plate, sector plate, non-uniform thickness.