Dynamic stiffness formulation for vibration analysis of thick composite plates resting on non-homogenous foundations

This research presents new continuous elements for thick laminated plates on a Pasternak or a non-homogeneous foundation using the Dynamic Stiffness Method (DSM). The non-homogeneous foundation consists of multi-section Winkler-type and Pasternak-type elastic foundation. The Dynamic Stiffness Matrices using the First Shear Deformation Theory (FSDT) are constructed based on the exact closed form solutions of the governing differential equations of both cross-ply and angle-ply thick composite plates on non-homogeneous elastic foundations and subjected to various types of boundary conditions. A computer program is written using the present formulation for calculating the natural frequencies and harmonic response of composite plates without contact with elastic foundation and composite plates resting on non-homogenous foundations. The validation is done by comparison of continuous element model with available results in the literature and with Finite Element Method (FEM). Different test cases confirm the advantages of the present model which is supposed to be especially efficient in dynamics analysis.