Exoskeletons of Odontodactylus japonicas, the “smasher-type” mantis shrimp, feature a raptorial appendage comprising a Bouligand architecture of chitin nanofibrils with newly observed voids or defects between the polysaccharide α-chitin and protein interfaces. Here, we use a continuous-fiber 3D printing technology to simulate such materials in carbon fiber-reinforced (helicoidal) composites, complete with the presence of voids due to imperfect printing. The specific impact energies of the 3D printed helicoidal composites are clearly superior and further enhanced by the presence of the voids. To explain the role of the Bouligand architecture, interlaminar stresses are computed and found to yield anti-delamination characteristics, and a theoretical model is derived to evaluate the optimal helicoidal architecture. Finite element modeling indicates that the voids tend to deform and coalesce on loading and appear to guide the fracture into the formation of an ideally twisted crack in the printed helicoidal composites, thereby contributing to the impact toughness.

日本齿齿龙的外骨骼，“粉碎型”螳螂虾，有一个附肢，包括几丁质纳米纤维的Bouligand结构，在多糖α-几丁质和蛋白质界面之间有新观察到的空隙或缺陷。在这里，我们使用连续纤维3D打印技术来模拟碳纤维增强（螺旋）复合材料中的此类材料，并由于不完美的打印而存在空隙。3D打印的螺旋复合材料的比冲击能明显优越，并且由于存在空隙而进一步增强。为了解释Bouligand体系结构的作用，计算了层间应力并发现了层间抗分层特性，并推导了理论模型来评估最佳螺旋结构。