Rigidity-toughness Coupling in Architected Composite Materials for Enhanced Impact Resistance

In recent decades, architected composite materials have received increasing attention due to its promising potential in improving the impact resistance performance compared with bulk materials. Some ingenious microstructures of biomaterials can enlighten the design of novel architected composite materials, such as nacre, conch shell and dactyl club of mantis shrimp, which have been extensively applied. Here, in order to further enhance the impact resistance of architected composite materials, hybrid architectures are proposed based on nacre-like brick-mud and sponge-like lamellar architectures. Then, their impact resistance performances and mechanism are investigated by combining experiment with finite element simulation. The results show that through positive hybrid design inspired of the dactyl club, the lamellar bottom makes the hybrid architecture retain excellent toughness, and the brick-mud top guarantees large flexural stiffness, thereby achieving rigidity-toughness coupling and boosting the energy absorption dramatically. Moreover, as the decline of volume ratio of soft phases within and between brick-mud layers, the energy absorption of brick-mud architecture gradually increases owing to the rising damage resistance. Further, the rigidity-toughness coupled effect can be optimized by positively hybridizing multiple architectures with larger variation in flexural stiffness and toughness, even achieving 375% improvement in energy absorption compared with the basic brick-mud architecture.