PLANE WAVES IN ANISOTROPIC PLATES

A finite element analysis is presented for predicting the dispersive characteristics in anisotropic plates under plane strain conditions The formulation consists of expressing the waveform along the propagation direction and in time explicitly, thus leaving the dependence through the thickness to be determined. An efficient eigensolution technique is employed to extract a subset of the lowest frequencies and modal patterns through the plate thickness. The same method can be used to extract frequencies and modal patters in the intermediate range with a shifting procedure. The accuracy of this method is verified by comparing finite element results for an AT-Cut Quartz plate with those obtained by means of a regula falsi procedure. Additional numerical examples on two stacking arrangements of four-layer composite plates and sandwich plates are also given.