Multiscale topology optimization and 3D printing of continuous carbon fiber reinforced composites lattice structure

3D printing of continuous carbon fiber reinforced composites (CCFRCs) enables the production of multiscale lattice structures, characterized by macro- and mesostructures defined by fiber trajectories. In this paper, a multiscale topology optimization and 3D printing framework for CCFRCs lattice structures was developed, where both macro-scale topological morphology and meso-scale unit cell orientation were simultaneous optimized, and was implemented through a well-connected 3D printing path. Benchmark structures, including the cantilever beam and the Messerschmitt-Bölkow-Blohm (MBB) beam, were optimized. The results demonstrated that structural stiffness and peak load were improved by 182.94 % and 57.96 %, respectively, compared to traditional lattice structures with uniformly distributed periodic unit cells, and by 143.72 % and 20.71 %, respectively, compared to topological lattice structures with fixed unit cells, highlighting effectiveness of the proposed method. Furthermore, an unmanned aerial vehicle (UAV) arm was designed using the proposed method and experimentally validated under operating load conditions. Based on this, a proof-of-concept UAV frame was developed and 3D printed, demonstrating the advantages of lightweight design and efficient manufacturing. Multiscale topology optimization and 3D printing could promote the potential of CCFRCs lattice structures, which hold enormous prospects in aviation, aerospace, and other fields.