Multi-bionic mechanical metamaterials: A composite of FCC lattice and bone structures

The structures evolved by creatures to adapt to the specific living environment have excellent mechanical properties. Studying from nature, we can get inspiration to design the structure with unparalleled mechanical properties. This paper proposed a new multi-bionic strategy, which combined the face centered cubic (FCC) structure with light weight and high specific strength and the concentric circle structure with high toughness. Those two structure were inspired by the arrangement of metal atoms and bone respectively. The multi-bionic metamaterials with different ratios of soft phase material were prepared by 3D printer. The force-displacement curves of the metamaterials were obtained by quasi-static compression experiment, and compared with the lattice structure made of pure hard phase material. In addition, the failure behavior of the metamaterials and the effect of the concentric soft and hard rods on the toughness and energy absorption performance of the metamaterials were studied. Results show that for a metamaterial with soft phase ratio of 20%, the strain when rods begin to break and absorbed energy are 2 times and 3.8 times that of the pure hard phase lattice, respectively. The design strategy is not only limited to the combination of the two structures in this work, but can also guide the combination of more biological structures to optimize and customize the performance of metamaterials.