中文摘要：

可实现负泊松比效应的蜂窝材料拥有独特的力学性能,在变体机翼柔性蒙皮等应用中,有着良好的前景.本文采用机械超材料的设计方法,改进了传统蜂窝材料的结构单元设计,提出了一种新型环形负泊松比结构,并建立了相应的力学模型.运用能量法研究了环形蜂窝芯结构的等效弹性模量与各结构参数之间的关系,建立了环形蜂窝芯在小形变范围内等效弹性模量的公式.通过有限元仿真,将理论计算结果与有限元计算结果进行对比,两者具有很好的一致性,验证了理论公式的正确性,对负泊松比机械超材料的设计与应用具有一定的指导意义.

英文摘要：

Mechanical metamaterials are artificial structures with mechanical properties defined by their structure rather than their composition. As a new type of metamaterials with unique mechanical properties and promising prospects, mechanical metamaterials have attracted great attention and become a new hot spot in the field of metamaterials. Mechanical metamaterials with negative Poisson＇s ratio can exhibit novel mechanical properties such as excellent resistance capability of bending deformation and indentation. This type of materials have good prospects in many applications such as variant flexible wing skin. In this article, we adopt the design method of mechanical metamaterials to improve the structure of traditional honeycomb core and propose a new type of circular honeycomb core unit to obtain negative Poisson＇s ratio. The advantage of circular honeycomb core is that this new structure is more stable than traditional concave hexagon honeycomb core. We established the corresponding mechanical model of this structure and adopted energy method to study the dependencies of structure parameters for its effective elastic modulus. The bending strain energy was taken into consideration while the tension and shear strain energy were ignored because they are very small compared with the bending strain energy. Then the expressions of effective elastic modulus in the directions of X and Y axis can be established in the condition of small deformation. In order to verify the validity of theoretical results, finite-element simulation method was employed to our study and we adopted periodic structure as the finite-element simulation model and aluminium alloy as the base material. The results of theory and the simulation have good agreements, and we found that its effective elastic modulus Ex is mainly depending on its height h and thickness t while Ey is mainly depending on its radius r and thickness t. And the thickness t may bring about deviation between theory and the simulation when it increases. The Poisson＇s ratio o