The material with negative Poisson's ratio (NPR) is a typical metamaterial, which is considered to have great prospects in energy absorption, but the low modulus and low strength of the materials are the biggest obstacles to its engineering applications. In this paper, the basic mechanical properties and energy absorption performance of an auxetic material with ultra-low density, named as a novel cross-chiral structure (NCCS), are systematically studied under quasi-static and dynamic compression. The results reveal that this auxetic material shows strong anisotropy and enhanced mechanical properties in the principal directions. Compared to the previously reported auxetic materials, it exhibits higher modulus and strength as well as superior energy absorption capability with the relative density less than 0.1, which is validated by both numerical simulations and experiments. In addition, the results indicate that the presented model can be optimized to achieve excellent mechanical properties and outstanding energy absorption capability with ultra-low densities, by tailoring strut's tilt angle and relative density. This architectured metamaterial is expected to find a bright future in the applications of energy absorption such as sandwich cores of armor.

泊松比（NPR）为负的材料是一种典型的超材料，被认为在能量吸收方面具有广阔的前景，但材料的低模量和低强度是其工程应用的最大障碍。本文在准静态压缩和动态压缩下，系统研究了一种超低密度膨胀材料的基本力学性能和能量吸收性能，该材料被称为新型交叉手性结构（NCCS）。结果表明，该膨胀材料在主要方向上显示出强各向异性和增强的机械性能。与先前报道的助燃材料相比，它具有更高的模量和强度以及出色的能量吸收能力，相对密度小于0.1，数值模拟和实验均对此进行了验证。此外，结果表明，通过调整支杆的倾斜角度和相对密度，可以优化提出的模型以实现出色的机械性能和出色的超低密度能量吸收能力。这种结构化的超材料有望在能量吸收的应用中找到光明的未来，例如铠装夹芯。