Geometrically nonlinear analysis of composite plates and shells via a quadrilateral element with good coarse-mesh accuracy

This paper presents an improved finite element computational model using a flat four-node element with smoothed strains for geometrically nonlinear analysis of composite plate/shell structures. The von-Karman’s large deflection theory and the total Lagrangian approach are employed in the formulation of the element to describe small strain geometric nonlinearity with large deformations using the first-order shear deformation theory (FSDT). The element membrane-bending and geometric stiffness matrices are evaluated by integration along the boundary of smoothing elements which can give more accurate numerical integrations even with bad shape distortions. The predictive capability of the present model is demonstrated by comparing the present results with analytical/experimental and other numerical solutions available in the literature. Numerical examples show that the present formulations can prevent loss of accuracy in distorted or coarse meshes, and therefore, are superior to those of other bilinear quadrilateral elements.