Materials with an abnormal Poisson's ratio, including those with negative Poisson's ratio (NPR) and zero Poisson's ratio (ZPR), are an important category of mechanical metamaterials, among which many exhibit NPR in all three directions. However, few of them, especially the 3D materials, exhibit ZPR in partial directions and NPR in other directions. Herein, a novel 3D structure developed by orthogonal splicing the 2D parallelogram honeycomb structure is proposed. Different from the 2D parallelogram honeycomb with ZPR, the spliced 3D parallelogram structure can exhibit not only ZPR but also NPR in different directions. The analytical model of the structure is established based on the classical beam theory, the equivalent analytical formulas of Young's modulus and Poisson's ratio are given, and finite element simulation and experiments are used for verification. The relationships between Young's modulus and Poisson's ratio of the structure, as well as its geometric parameters and material parameters, are analyzed using analytical formulas and numerical simulation. The results reveal that the structure is transversely isotropic and can achieve NPR on the transverse symmetry plane and ZPR outside the plane. This unique property may accord this structure with important applications in aerospace, biomedical, and other fields.

中文翻译：

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部分方向上泊松比为零的不寻常3D超材料

具有异常泊松比的材料，包括具有负泊松比（NPR）和零泊松比（ZPR）的材料，是机械超材料的重要类别，其中许多材料在所有三个方向上都显示NPR。但是，它们中的极少数，尤其是3D材料，在局部方向上显示ZPR，而在其他方向上显示NPR。在此，提出了通过正交拼接2D平行四边形蜂窝结构而开发的新颖的3D结构。与具有ZPR的2D平行四边形蜂窝不同，拼接的3D平行四边形结构不仅可以显示ZPR，还可以在不同方向上显示NPR。基于经典梁理论建立了结构解析模型，给出了杨氏模量和泊松比的等效解析公式，并采用有限元模拟和实验进行验证。使用解析公式和数值模拟分析了结构的杨氏模量和泊松比之间的关系，以及其几何参数和材料参数。结果表明，该结构是横向各向同性的，可以在横向对称平面上实现NPR，而在平面对称平面外则可以实现ZPR。这种独特的特性可以使这种结构与航空航天，生物医学和其他领域的重要应用相匹配。结果表明，该结构是横向各向同性的，可以在横向对称平面上实现NPR，而在平面对称平面外则可以实现ZPR。这种独特的性质可能使这种结构与航空航天，生物医学和其他领域的重要应用相吻合。结果表明，该结构是横向各向同性的，可以在横向对称平面上实现NPR，而在平面对称平面外则可以实现ZPR。这种独特的特性可以使这种结构与航空航天，生物医学和其他领域的重要应用相匹配。