Nonplanar Bouligand Architectures for Enhanced Mechanical Performance in Cementitious Composites

Brittle and quasi-brittle materials such as hydraulic cement-based materials, glass, and ceramics exhibit limited toughness and poor energy absorption, often leading to catastrophic failure under extreme loading. Inspired by the dactyl club of the Mantis shrimp, we introduce a sinusoidal Bouligand architecture into concrete enabled by nonplanar additive manufacturing. Under quasi-static compression, the elements with sinusoidal Bouligand architecture exhibit a 53.6% higher compressive strength and a 216.1% greater work of failure than regular 3D-printed elements, while also outperforming cast counterparts by 13.5% in strength and 35% in work of failure. Under impact loading, the sinusoidal Bouligand samples exhibit up to a 68.6% increase in peak load and a 49.2% increase in absorbed energy compared to cast counterparts. These improvements enable the architected samples to maintain structural integrity without catastrophic failure, whereas the cast samples fail by highly localized fracture. Fiber alignment during 3D printing induces strong and tunable local anisotropy which, coupled with the sinusoidal Bouligand architecture, enables interfacial crack deflection, crack twisting, and damage delocalization. These results demonstrate the effective translation of biological toughening principles into engineered materials and establish a design paradigm for cementitious composites with enhanced damage tolerance and energy-absorbing capability.