Abstract Traditional auxetic lattices are featured with negative Poisson's ratio but weak stiffness. In this work, a set of auxetic lattices with enhanced stiffness are proposed by adding a strengthening rib into conventional auxetic unit cells in a direction perpendicular to the re-entrant direction. The effective mechanical properties of these variants are calculated using the fast Fourier transform-based homogenization method, which show that their Young's modulus in 2D can be improved by approximately 200% along the strengthening direction without significant sacrifice of auxetic property. However, such an enhancement is weakened in 3D as the variant of a tetrahedral cell has an approximate 100% improvement of Young's modulus only at low relative density. Though the stiffness of a variant hexahedral cell can be doubled in 3D at a wide range of relative density, its Poisson's ratio remains negative only in a narrow range of relative density. The findings in this work will offer new opportunities for the applications of auxetic materials which not only need negative Poisson's ratio but also high stiffness.

中文翻译：

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具有增强刚度的可重入拉胀晶格：数值研究

摘要 传统拉胀晶格具有泊松比为负但刚度较弱的特点。在这项工作中，通过在垂直于凹入方向的方向上将加强肋添加到传统拉胀晶胞中，提出了一组具有增强刚度的拉胀晶格。这些变体的有效机械性能是使用基于快速傅立叶变换的均质化方法计算的，这表明它们在二维中的杨氏模量可以沿强化方向提高约 200%，而不会显着牺牲拉胀性能。然而，这种增强在 3D 中被削弱，因为四面体单元的变体仅在低相对密度下具有大约 100% 的杨氏模量改进。尽管变体六面体单元的刚度可以在较宽的相对密度范围内在 3D 中加倍，但其泊松比仅在较窄的相对密度范围内保持为负。这项工作的发现将为拉胀材料的应用提供新的机会，这些材料不仅需要负泊松比，而且还需要高刚度。