Vibration of annular elliptic orthotropic plates using two dimensional orthogonal polynomials
The free vibration natural frequencies of specially orthotropic annular elliptic and circular plates are analyzed by the Rayleigh-Ritz method, using two-dimensional boundary characteristic orthogonal polynomials generated following a recurrence scheme as assumed shape functions. The first eight natural frequencies are reported here for various values of aspect ratios of the outer and inner ellipse. Results are given for various boundary conditions at the inner and outer edges of the annular plate. The influence of the material property as it changes from isotropic to orthotropic on the natural frequencies is presented graphically. When the inner hole of the annular plate becomes zero i.e. for rectangular orthotropic full circular and elliptic plates, the results are compared with those that are available in the existing literature, and are found to be in good agreement. Presented results may be used as bench marks for validating those obtained by approximate methods such as the finite element method.
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