Free vibration analysis of Reissner plates by mixed finite element

In this study, free vibration analysis of Reissner plates on Pasternak foundation is carried out<br />by mixed finite element method based on the Gateaux differential. New boundary conditions are<br />established for plates on Pasternak foundation. This method is developed and applied to numerous<br />problems by Akoz and his co-workers. In dynamic analysis, the problem reduces to the solution of a<br />standard eigenvalue problem and the mixed element is based upon a consistent mass matrix formulation.<br />The element has four nodes and bending and torsional moments, transverse shear forces, rotations and<br />displacements are the basic unknowns. The element performance is assessed by comparison with<br />numerical examples known from literature. Validity limits of Kirchhoff plate theory is tested by dynamic<br />analysis. Shear locking effects are tested as far as h/2a =10 -6 and it is observed that REC32 is free from<br />shear locking.