Coupling design and fabrication of continuous carbon fiber-reinforced composite structures using two-material topology optimization and additive manufacturing

This study presents an integration of the level set-based two-material topology optimization method and the additive manufacturing technique for the design and fabrication of continuous carbon fiber (CCF)-reinforced composite structures. Firstly, optimal configurations of the resin material and fiber reinforcement are obtained to maximize the structural stiffness under desired volume constraints using the two-material topological optimization. After that, the level set-based cutting mesh method and triangulation scheme are employed to interpret these topological designs into stereolithography (STL) models with clear structural boundaries for the manufacturing. A customized pre-processing strategy is used to accurately determine the fiber placement regions from the optimal designs. Topological results are then fabricated using the CCF-based 3D printing method with prepreg carbon fibers. Subsequently, the performance of printed CCF-reinforced composite structures is investigated, using different resin materials: polylactic acid (PLA) and polyamide 12 with 10 carbon fiber (PA1210CF). Experimental results indicate a significant increase in stiffness and strength of composite structures with fiber reinforcements for all resin materials, with an increase of 315 for PLA and 234 for PA1210CF. Additionally, the CCF-reinforced composite structures made of PA1210CF exhibit superior stiffness compared to those made of PLA with a double increment. The microstructural characteristics of damaged regions are examined using scanning electron microscope (SEM) images, which provide valuable insights into the behavior of resin and fiber materials. © 2024, The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.