Iterative free edge stress analysis of composite laminates under extension, bending, twisting and thermal loadings

The iterative method has been applied to analyze the free edge interlaminar stresses of composite laminates. The laminates are subjected to extension, bending, twisting and thermal loads. Using the complementary virtual work and the extended Kantorovich method, the stresses satisfying the traction-free conditions not only at the free edges, but also at the top and bottom surfaces of laminates are obtained. By applying the static and kinematic continuity conditions at the interfaces between plies through iterations, the present method predicts interlaminar stresses accurately. To demonstrate the validity of the proposed method, cross-ply, angle-ply, and quasi-isotropic laminates are considered. Through the iteration processes, the convergence of the solutions is demonstrated. The present method provides accurate stresses in the interior and near the free edges of laminates. It can serve as an analytical tool to predict interlaminar stresses under the combined mechanical and thermal loads.