Optimization of Blended Composite Wing Panels Using Smeared Stiffness Technique and Lamination Parameters

Abstract

§** The smeared stiffness-based method is examined for finding the best stacking sequence of laminated composite wing structures with blending and manufacturing constraints . In this method, numbers of plies of the pre-defined angles (0, 90, 45 and -45 degrees) are design variables, buckling, strain and ply angle percentages are constraints and the material volume is the objective function at the global level . The ply shuffling to satisfy global blending and manufacturing constraints is performed at the local level to match zero values of lamination parameters. The latter requirement is due to the ply angle homogeneity through the stack that is assumed in the top level optimization. This integrated process utilizing the smeared stiffness technique and lamination parameters is demonstrated by the optimization of the root part of a generic aircraft wing structure. The local level optimization can be seen as a postprocessing phase for determining the detailed ply-book of the laminate.