Investigation on Low-velocity Impact Response and Energy Absorption of Enhanced X-shaped Lattice Mechanical Metamaterials

Lattice mechanics metamaterials have been widely used in various fields due to the lightweight, flexible designability and excellent impact resistance. In this paper, the enhanced X-shaped lattice mechanical metamaterials were designed and prepared by selective laser melting. The dynamic crushing behavior and energy absorption mechanism of lattice mechanics metamaterials subjected to low-velocity impact were carried out experimentally and numerically. The influence of impact velocity on the deformation mode and energy absorption capability of the enhanced X-shaped lattice mechanical metamaterials was analyzed. It is shown that the impact velocity has significant effects on the deformation mode of the mechanical metamaterials. The active deformation mode of X-shape lattice mechanical metamaterials subjected to lower impact velocity and quasi-static compression is collapse layer by layer. At higher impact velocities, the deformation modes of lattice mechanical metamaterials evolve sequentially from "X"-shaped to "V"-shaped and finally to arc-shaped shear bands. The enhanced X-shaped lattice mechanical metamaterials exhibit rate sensitivity. The initial peak stress, plateau stress and specific energy absorption increase with an increase in the impact velocity.