A GLOBAL-LOCAL FINITE-ELEMENT FOR GENERAL COMPOSITE STRUCTURE

A global-local approach based on a mixed variational functional has been followed in this study. For global region of the laminate, the potential energy has been utilized, while the Reissner functional has been used for the local region. The field equations are based on an assumed thickness distribution of stress component within each layer of the local domain. The displacement field equations are assumed in the global region and are extended into local region for continuity. A set of equilibrium equations has been derived for the entire structure. The analysis transforms the 3D elasticity problems into 2D problems in a self-consistent approach that features realistic satisfaction of boundary and interface or interlayers condition. A set of boundary value problems (i.e. bending, thermal load, uniform inplane tensile stress, and uniform inplane tensile strain load) have been studied by global-local and local approaches. An important aspect of this research work is to use the frontal method to reduce the size of the structure matrix so that more plies and more refined mesh can be studied.