Design of variable stiffness composite structures using lamination parameters with fiber steering constraint

In this study, a lamination parameter based optimization algorithm is developed in a finite element framework using classical plate deformation theory. The optimization reveals lamination parameter distribution over the plate which are then converted into fiber directions, stacking sequences and layer thicknesses by means of a material library. The optimum fiber angles in each ply are used to find continuous fiber angle distributions a using weighted residual method for the first time. The method uses finite element based least-squares and continuity constraint (LSC) to find a manufacturable design without making any preliminary assumption such as splines, stream functions, etc., for the fiber angle distributions. Penalty parameter is used to enforce a maximum limiting value for the fiber curvatures. The proposed method is applied to design for the minimum compliance in-plane and out-of-plane problems, and significant improvements are obtained in comparison to the literature findings.