【作者】 李明；

【导师】 周振功；

【作者基本信息】 哈尔滨工业大学 ， 力学， 2021， 硕士

【摘要】 近年来随着机械超材料研究的兴起,负泊松比结构、负热膨胀结构作为一类设计新颖、性能独特的超材料结构受到了广泛关注。负泊松比结构因其“拉胀特性”在抗剪承载力、抗断裂性、能量吸收和压陷阻力等方面比传统材料更有优势,而负热膨胀结构的反常识的“热缩冷胀”现象使其在温度变化的环境下仍然有很好的结构稳定性。目前很多研究人员尝试将负泊松比结构和负热膨胀结构结合,设计一种兼具负泊松比和负热膨胀两种特性的机械超材料。本文在拉伸主导型负热膨胀结构的代表性三角形单胞的基础上进行改进,提出了一种可调控泊松比和热膨胀系数的双V结构。主要研究内容如下:首先,基于拉伸主导型负热膨胀结构的代表性三角形单胞,提出了可调控泊松比和热膨胀系数的双V结构设计方案,实现了横向泊松比和纵向热膨胀系数从正到零再到负的大范围调控。其次,采用堆叠粘接组装的制备方法,基于该制备方法制备了一系列不同角度组合、材料组合的双V结构,针对结构热膨胀系数测试困难这一问题设计了一套热膨胀系数测试系统,较为精确地测试了双V结构纵向热膨胀系数。最后,建立了双V结构理论分析模型,研究了双V结构的力学和热变形行为,得到了几何参数、材料组合参数对横向泊松比和纵向热膨胀系数的调控规律。更多还原

【Abstract】 In recent years,with the rise of research on mechanical metamaterials,negative Poisson’s ratio structures and negative thermal expansion structures have received widespread attention as a class of metamaterial structures with novel designs and unique properties.Negative Poisson’s ratio structure has advantages over traditional materials in terms of shear resistance,fracture resistance,energy absorption and compression resistance due to its tensile expansion characteristics.However,the abnormal thermal contraction and cold expansion phenomenon of the negative thermal expansion structure makes it still have good structural stability under the environment of temperature changes.At present,many researchers try to combine negative Poisson’s ratio structure and negative thermal expansion structure to design a mechanical metamaterial with both negative Poisson’s ratio and negative thermal expansion.Based on the representative triangular unit cell of the tensile-dominant negative thermal expansion structure,this paper proposes a double V structure that can control Poisson’s ratio and thermal expansion coefficient.The main contents are as follows:First,based on the representative triangular unit cell of the tensile-dominant negative thermal expansion structure,a double-V structure design scheme that can adjust Poisson’s ratio and thermal expansion coefficient is proposed,which realizes the adjustment of lateral Poisson’s ratio and longitudinal thermal expansion coefficient from positive to negative..Secondly,using the stacking bonding assembly method,a series of double V structures with different angle combinations and material combinations are prepared based on this method.A set of thermal expansion coefficient test system is designed to solve the problem of difficult structural thermal expansion coefficient testing.The longitudinal thermal expansion coefficient of the double V structure was tested.Finally,the theoretical analysis model of the double-V structure was established,and the mechanical and thermal deformation behavior of the double-V structure was studied,and the regulation laws of geometric parameters and material combination parameters on the transverse Poisson’s ratio and the longitudinal thermal expansion coefficient were obtained.更多还原