Mechanics and Failure Mechanisms of Rigid–Flexible 3D-Printed FRP Miura-Ori Structures

The integration of multi-material 3D printing with origami engineering offers a promising avenue for deployable structures, but weak interfacial bonding between rigid and flexible phases remains a key limitation. This study first proposed four distinct hinge designs (enclosed, interlaced, inserted, and interlocked) for Miura-ori architectures, and subsequently investigated their mechanical behaviors with further elucidation of stress-transfer efficiency and interfacial failure modes under static tensile or compressive loading. Research outcomes identified the 5.0 mm interlaced hinge as the optimal interface design, improving stress distribution at the rigid–flexible interface and suppressing premature debonding. Notably, the dominant failure mode shifted from interfacial separation to ductile fracture within a TPU elastomer. Further research proves that increasing the embedment depth of the interlaced hinge from 1.0 mm to 5.0 mm can significantly increase fracture elongation from 100.8% to 342.4% while maintaining a stable peak tensile strength of approximately 12.5 MPa. At the structural scale, dual-material printed Miura-ori architecture exhibits better mechanical performance than single-material printed spatial counterparts (5163 N vs. 4019 N in compressive capacity, 18.7 mm vs. 8.0 mm in fracture elongation). These findings provide valuable insights into high-performance deployable structure design based on multi-material additive manufacturing.