Regulating the inherent Poisson's ratio of soft elastic materials under large deformation is important for their application in emerging fields, such as morphing structures and stretchable electronics. In this study, we selected a composite in which an auxetic honeycomb was embedded in a soft material to regulate the in-plane Poisson's ratio. Based on a cantilever beam model, a theoretical model was established to guide the design optimization of composite structures. The macroscopic constitutive relation and in-plane Poisson's ratio of the composite structures with different configurations were predicted by the theoretical model, which were consistent with the finite element analysis results. In the 30% strain range, the slope of the Poisson's ratio–strain curve decreases with an increase in the length of the inclined bar, and the in-plane Poisson's ratio increases with an increase in the angle between the transverse bar and the inclined bar. In addition, we propose an optimization design method with the in-plane Poisson's ratio as the objective function and then optimize and fabricate a skin structure with an in-plane Poisson's ratio of approximately zero for the morphing wings. The achievements of this study provide theoretical guidance for regulating the in-plane Poisson's ratio of thin flexible layers.

中文翻译：

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大变形下具有可定制面内泊松比的柔性复合材料结构

调节软弹性材料在大变形下固有的泊松比对于其在新兴领域（例如变形结构和可拉伸电子产品）的应用非常重要。在这项研究中，我们选择了一种复合材料，其中将拉胀蜂窝嵌入软材料中以调节面内泊松比。基于悬臂梁模型，建立了指导复合材料结构设计优化的理论模型。理论模型预测了不同构型复合材料结构的宏观本构关系和面内泊松比，与有限元分析结果一致。在30%应变范围内，泊松比-应变曲线的斜率随着斜杆长度的增加而减小，面内泊松比随着横杆与斜杆夹角的增加而增大。此外，我们提出了一种以面内泊松比为目标函数的优化设计方法，然后优化并制造了变形机翼面内泊松比近似为零的蒙皮结构。该研究成果为柔性薄层面内泊松比的调控提供了理论指导。