Haldar, S.Manna, M.Sheikh, A.2008-07-152008-07-152003International Journal of Applied Mechanics and Engineering, 2003; 8(3):441-4481734-44921425-1655http://hdl.handle.net/2440/46505A free vibration analysis of isotropic plates is investigated in this paper. A sixteen node sub-parametric element having thirty-six degrees of freedom is developed for this purpose. The transverse displacement and bending rotations are taken as independent field variables. The polynomials used to express these variables are of the same order. The entire formulation is made based on the first-order shear deformation theory (FSDT). The rotary inertia is included in the consistent mass matrix for the analysis. Isotropic plates with different thickness ratios, aspect ratios and boundary conditions are analyzed. The results show an excellent agreement with the available published analytical results.enfree vibrationsub-parametric elementfirst-order shear deformationrotary inertiathickness ratiosJournal article00200817382008071510230242601