EFFECT OF TRANSVERSE-SHEAR DEFORMATION AND ROTARY INERTIA ON THE NATURAL FREQUENCIES OF RECTANGULAR-PLATES WITH CUTOUTS

A numerical method based on the Rayleigh principle is applied in conju nction with the simplified Reissner-Mindlin theory which involves only a single variable, the transverse displacement, for predicting the fu ndamental frequencies of rectangular plates with rectangular cutouts. The predicted results are compared with the finite elements results an d the reported works available in the literature. It is concluded that the effect of rotary inertia can only be neglected for orthotropic pl ates with high degrees of orthotropy. For isotropic plates, the effect of rotary inertia becomes more pronounced with respect to the effect of transverse shear deformation with increased cutout size.