MITC finite elements for laminated composite plates

Within the framework of the rst-order shear deformation theory, 4- and 9-node elements for the analysis of laminated composite plates are derived from the MITC family developed by Bathe and coworkers. To this end the bases of the MITC formulation are illustrated and suitably extended to incorporate the laminate theory. The proposed elements are locking-free, they do not have zero-energy modes and provide accurate in-plane deformations. Two consecutive regularizations of the extensional and exural strain elds and the correction of the resulting out-of-plane stress pro les necessary to enforce exact ful llment of the boundary conditions are shown to yield very satisfactory results in terms of transverse and normal stresses. The features of the proposed elements are assessed through several numerical examples, either for regular and highly distorted meshes. Comparisons with analytical solutions are also shown