LARGE DEFLEXION ANALYSIS OF ORTHOTROPIC PLATES INCLUDING SHEAR DEFORMATION EFFECT.

The non-linear behavior of orthotropic plates subject to transverse loading is investigated using higher-order finite elements. The formulation procedure for elements with up to 25 nodes and derivation of the flexural and tangential stiffness matrix based on the classical von Karman nonlinear theory are referred to. These elements are derived by employing a high order polynomial displacement function to represent the in-plane and the bending displacements. By adopting separate variables for the transverse deflexions and the rotations of the plate, the effect of transverse shear deformation can be included in modeling thin to moderately thick plates, thus enabling the effect of transverse shear on the nonlinear behavior of plates to be included. A modified version of the Newton-Raphson method for solving nonlinear equations is adopted to obtain the final state of equilibrium of the system.