Dynamic response of composite plates with cut-outs,part II: Clamped-clamped plates

The forced and free dynamic response of plates with cut-outs formulated in Part I 1] is used to investigate the effect of cut-outs on the natural frequencies of clamped-clamped plates. The size, shape and location of the cut-out is expressed as a displacement dependent external loading. The plates considered are homogeneous and anisotropic. Lagrange's equations of motion lead to an infinite system of differential equations in time-dependent generalized co-ordinates with generalized forces which include the effects of the cut-outs. There is an infinite system of frequency equations for free vibrations. The infinite system is truncated to a finite system of equations depending upon the accuracy desired in frequency values. Results are given for square, clamped-clamped plates with centrally located square cut-outs for different modulus ratios. Good agreement is obtained when results for isotropic plates with cut-outs are compared with available theoretical and experimental results.