Flexural vibrations of composite orthotropic annular plates with edge-damage

The free vibrational response of clamped homogeneous or symmetrically laminated orthotropic annular plates with edge damage on the outer circumference has been studied for the first time, using the finite difference method. The edge damage is modeled via the application of a non-uniform boundary condition. The sensitivity of vibrational frequencies to the extent of the edge damage is investigated and shown to be strongly influenced by the material properties and the relative thicknesses of the materials comprising the laminated plates. It is shown that the orthotropy ratio for the plate (defined here by Drr/Dθθ) is a convenient compact parameter for indicating the sensitivity to edge damage. Mode shapes are also computed and found to be profoundly affected by the orthotropy ratio. The behavior of higher modes of vibration is also discussed and the phenomenon of cross over, whereby two modes exist having the same frequency, is observed.