Additive manufacturing of continuous fiber composite curved thin-walled structures with conformal honeycomb-stiffeners based on topology optimization

• A conformal mapping-based topology optimization method is developed to ensur G 1 continuity in thin-walled structures with honeycomb-stiffeners. • A path filling strategy is developed for additive manufacturing of complex curved thin-walled structures using fiber-reinforced composites. • Defect characterization reveals void distribution in the manufactured components based on computed tomography. • The proposed conformal filling method improves failure displacement by 25.9%. Continuous fiber-reinforced composite (CFRC) thin-walled structures integrated with conformal lattice-stiffeners demonstrate exceptional mass-efficiency and specific stiffness relative to conventional metallic stiffened structures, establishing significant deployment potential in aerospace and transportation systems. Nevertheless, structural performance remains critically limited by non-optimal material distribution and fiber placement. To address these challenges, this study proposes an integrated design-manufacturing framework comprising three innovations: (1) A conformal mapping-based topology optimization method incorporating a higher-order interpolation scheme (guaranteeing G 1 continuity) at lattice interfaces; (2) A fiber trajectory planning methodology specifically adapted for curved thin-walled structures; (3) Micro-computed tomography (μCT)-enabled defect characterization quantifying void spatial distributions in additively manufactured (AM) CFRC components. Simulation results demonstrate that the integrated honeycomb-stiffener structure achieves 57.3% and 44.5% maximum stress reduction compared to isolated honeycomb and stiffener benchmark structures, respectively. Comparative evaluation of fiber path planning methods reveals that the contour method achieves superior fiber volume fractions in curved thin-walled structures. Three cases involving optimized design, CFRC-AM, and μCT inspection confirms the proposed framework. The synergy between geometric continuous design and defect-controlled manufacturing advances the development of high-performance CFRC aerospace components.