MODELING OF THICK COMPOSITES USING A LAYERWISE LAMINATE THEORY

The layerwise laminate theory of Reddy1 is used to develop a layerwise, two-dimensional, displacement-based, finite element model of laminated composite plates that assumes a piecewise continuous distribution of the tranverse strains through the laminate thickness. The resulting layerwise finite element model is capable of computing interlaminar stresses and other localized effects with the same level of accuracy as a conventional 3-D finite element model. Although the total number of degrees of freedom are comparable in both models, the layerwise model maintains a 2-D-type data structure that provides several advantages over a conventional 3-D finite element model, e.g. simplified input data, ease of mesh alteration, and faster element stiffness matrix formulation. Two sample problems are provided to illustrate the accuracy of the present model in computing interlaminar stresses for laminates in bending and extension.