Lattice-based deployable composite booms regulated by flexible strips with enhanced fold-deploy performance

Aiming at the contradiction between load-bearing and folding of traditional thin-walled lenticular deployable composite booms (DCBs) and insufficient radial load-bearing of lattice-based DCBs, this paper proposes a flexible strip-regulated 3D printed lattice-based DCBs design. Geometric parameters are determined via design, and specimens are fabricated by dual-nozzle FDM 3D printing and compression-molded curved forming. Through radial compression experiments, finite element simulations, and theoretical modeling, the regulation laws of flexible strip number and pre-tension on mechanical properties are studied, with folding-unfolding cyclic tests verifying reliability. Results show that 3 and 5 flexible strips increase radial stiffness by 255.0 % and 375.0 % respectively, without raising the maximum folding stress, and enhance elastic strain energy by 17.9 % and 29.8 %; pre-tension improves load-bearing, and increasing cross-sectional height from 40.0 mm to 50.0 mm boosts radial stiffness by 52.1 % and elastic strain energy by 50.7 % with stable folding stress. An analytical model for radial compression force is established based on Kagome lattice homogenization and moment equilibrium, with a relative error < 5.0 % vs FEA results; cyclic tests show no obvious degradation, demonstrating excellent stability. This strategy achieves synergistic improvement of radial load-bearing and folding, offering a new approach for high-load, high-folding-ratio space deployable composite booms.