Optimal design of tapered composite structures with a dynamic boundary subset blending model

Based on the classical bending rule that the plies composing the thinner region should be a subset of the ones of the thicker region for two adjacent laminates, a genetic algorithm–based dynamic boundary subset blending model is proposed to optimize the global stacking sequence of composite structures with ply-drops. Besides the stacking sequence chromosome of the guide laminate and ply number chromosome of each panel, a chromosome of a dynamic boundary subset factor is introduced for each panel to obtain a fully blended design. The lower and upper bounds of the dynamic boundary subset factor chromosome for each panel is determined by the ply number chromosomes of the panel and its adjacent panels. The stacking sequence of each panel can be determined by selection from combinations of various stacking sequences. The proposed blending model can solve the problem that laminates with identical thicknesses have the completely same layups even when they are not adjacent to each other. The optimal feasible designs outperform other published solutions for the 18-panel horseshoe configuration problem based on the classical bending rule.