Optimum design of composite structures with curved fiber courses

In this study, a new methodology for the optimum design of laminated composites with curved fiber courses is presented. The objective of the optimization problem is to minimize the weight of the composite laminate under stress constraints. The Tsai– Hill criterion is employed on the first ply failure basis. Layer thicknesses and fiber angles are represented by bicubic Bezier surfaces and cubic Bezier curves, respectively. Design variables are coordinates of control points of the corresponding Bezier splines. The design variable linking procedure is used in order to reduce the number of design variables further and to provide symmetry in the design. The sequential quadratic programming is used in the optimization. The modeling of the laminate is carried out by using three-node shell finite elements.