GEOMETRICALLY NONLINEAR ANALYSIS of LAMINATED COMPOSITE MINDLIN PLATE WITH MIXED FINITE ELEMENT METHOD

The geometric nonlinear behavior of laminated composite plates in the scope of large deflection under static loading is analyzed by the method of mixed finite elements. Field equations are derived from the conjunction of Mindlin plate theory and von Karman strain definitions. Nonlinear finite element equations are obtained through the Hellinger-Reissner principle. Later on incremental formulation is adopted to obtain the linearized form of finite element equations which are suitable for a mixed finite element solution. In the procedure of finite element solution Newton-Raphson method is used to obtain numerical results. The formulation which is presented for analysis of moderately thick plates can automatically overcome the shear locking problem which is faced in thin plate solution, in addition; the method provides the possibility of obtaining stres resultants directly from numerical procedure.