Fundamental frequencies of annular plates with internal cracks

The Rayleigh method with a simple sub-sectioning technique has been used to obtain fundamental frequencies of annular plates with internal concentric cracks. Single-term deflection functions which satisfy the respective boundary conditions for the bending of an annular plate are used as admissible functions. The predicted fundamental frequencies are in good agreement with the reported analytical results for annular plates without any internal cracks. Numerical results for fundamental frequencies are presented for annular plates with internal cracks simply supported and clamped on both the outside and inside edges of the plates.