Geometrically non-linear analysis including shear deformation of composite laminates

Geometrically non-linear deformations of composite laminated plates are computed using the perturbation finite element method (PFEM). The PFEM is more economic in terms of computational time than conventional finite element iterative procedure, and results in semi-analytic solutions because deformations are polynomial functions of external loads, and vice-versa. To account for the transverse shear effect on deformation of a laminated plate, a discrete-layer shear deformation theory is introduced. This approach predicts more accurately the distribution of displacements and stresses through the thickness than single-layer theories. Detailed derivation of the theory is presented in the paper. A three-node triangular element model and computer program have been developed and implemented as part of this study. Computed numerical results of several examples show that the perturbation finite element solutions are in good agreement with exact solution, experimental data and calculated numerical result from other investigators.