Free vibration analysis of functionally graded sandwich plates using a new discrete kirchhoff four node quadrilateral element

In the present work, a four node quadrilateral element is developed for the free vibration analysis of functionally graded moderately thick sandwich plates. The element has seven degrees of freedom per node namely, two in-plane displacements, the transverse displacement, two rotations of mid plane and two transverse shear strain components at the mid plane. In the present study, two models of the material property variation through the thickness, namely; power law model and Mori-Tanaka model are considered. The results for sandwich plates with different thickness configurations and with different boundary conditions are compared with the available analytical and finite element results. For some cases, the present results of the non-dimensionalised frequencies are compared with those obtained using commercial software ANSYS. It is observed that the performance of the present element is quite satisfactory for the sandwich plates considered in this study.