Additively manufactured Shape Memory Alloy Hybrid Composites with a polymer matrix featuring a re-entrant honeycomb structure

The study combines stereolithography (SLA) and tailored fiber placement (TFP) to fabricate shape memory alloy hybrid composites (SMAHCs) in an integrated additive manufacturing process. The composites use SMA wires as active elements attached to a textile reinforcement layer, which is embedded in a UV-curable polymer matrix. A geometrically tailored top layer with a re-entrant honeycomb architecture is included to help control stiffness and deformation. The authors report that by exploiting SLA design freedom, the overall mechanical response can be systematically adjusted to achieve controlled out-of-plane bending during thermal activation. They compare two SMA integration strategies—manual embedding versus automated TFP—and manufacture eight geometric configurations. Experimentally characterized using synchronized optical measurements, the results indicate that automated TFP improves reproducibility and yields more symmetric deformation behavior than manual fabrication, while the re-entrant honeycomb structure helps tailor stiffness and deformation characteristics.