High Robustness and Multistability of Small Mesoscale Continuous GFRP Metamaterials: Novel Möbius Strip Structure.

Fiber-reinforced polymer composite mechanical metamaterials have emerged as promising candidates for multifunctional structural applications owing to their exceptional strength-to-weight ratios. However, achieving concurrent high stiffness, high strength, and large recoverable strain in such structures remains challenging due to inherent trade-offs between these properties. To address this limitation, a novel Möbius-inspired metamaterial through optimized fiber orientation design is developed. Notably, compared to conventional fully composite metastructures, the design achieves a 67% reduction in unit cell size while maintaining comparable stiffness and enhanced recoverable strain capacity. The proposed structure exhibits three distinctive characteristics: effective low-frequency sound insulation, reconfigurable adaptability, and secondary deformability after the hot molding process. These synergistic effects enable enhanced collaboration, enable multifunctional capabilities, including noise reduction, programmable Poisson's ratio (-0.4 to +0.6), and mechanical switching behavior. These performance improvements originate from synergistic fiber-matrix interactions and unique bending-twisting deformations inherent to the Möbius geometry, which are previously undocumented in fully composite metamaterials. This deformation mode facilitates significant elastic energy storage while minimally influencing peak stress levels associated with material failure. These findings elucidate a fundamental mechanism for developing high-performance composite metamaterials with tailorable energy storage capacity, addressing critical challenges in adaptive structural engineering.