Dynamic Compression Mechanical Behavior of Three-Dimensional Chiral Mechanical Metamaterials: Effects of Geometric Parameters and Size.

The coupled compression-torsion effects of three-dimensional chiral mechanical metamaterials have attracted widespread attention from researchers in recent years. However, the deformation rules and mechanisms through which geometric parameters and size affect their quasi-static and low-speed dynamic compression behavior are still unclear. This paper numerically investigates the quasi-static and low-speed dynamic compression mechanical behavior of three-dimensional chiral mechanical metamaterials, and the effects of geometric parameters and size are discussed. The numerical results are validated by their comparison with the experimental data. The testing results indicate that the geometric parameters as well as number of arrays in different directions have a significant effect on the quasi-static and dynamic compression twist angle per axial strain and the effective modulus. Interestingly, the values of the twist angle per axial strain under static and dynamic compression are almost the same under the same strain, but the effective modulus decreases more sharply under dynamic loading conditions, which may be due to inertia. Our work elucidates the mechanism through which geometric parameters and size affect the quasi-static and dynamic deformation behavior of three-dimensional chiral mechanical metamaterials, which provides design references for their practical engineering applications.