零泊松比反向半凹入式蜂窝结构设计与力学分析

Design and mechanical analysis of a reverse semi-re-entrant honeycomb structure with zero Poisson's ratio

  • 摘要: 针对变体机翼柔性蒙皮的变形与承载需求,设计了一种新型零泊松比(ZPR)反向半凹入(RSRE)蜂窝结构。基于卡氏第二定律建立了RSRE结构弹性常数理论模型,表明该结构的等效弹性模量较基体材料低2-4个数量级,其最大全局应变可达基体材料的6-7倍。深入探讨了胞元几何参数对结构面内变形能力的影响,结果显示胞壁宽度对结构变形能力的影响最大,其次是胞元内角。并与已有的星形零泊松比蜂窝结构进行对比,本文提出的RSRE结构弹性模量更低,变形能力更强。通过实验验证了理论模型和有限元仿真结果的可靠性。在结构制备方面,提出了一种结合模压成型与缠绕工艺的制备方法,用于制造碳纤维复合材料反向半凹入(CFRP+RSRE)蜂窝结构。与层合板切割方法相比,该工艺制备的试件面内承载能力提升约290%,失效位移增加了160%。

     

    Abstract: A novel zero Poisson's ratio (ZPR) reverse semi-re-entrant (RSRE) honeycomb structure was designed for the deformation and load-bearing requirements of the flexible skins of the morphing wing. A theoretical model for the elastic constants of the RSRE structure was established based on Castigliano’s second theorem, which shows that the equivalent modulus of elasticity of the structure is 2-4 orders of magnitude lower than that of the base material, and its maximum global strain can be up to 6-7 times that of the base material. The influence of the geometrical parameters of the cell element on the in-plane deformation capacity of the structure was deeply discussed, and the results show that the width of the cell wall has the greatest influence on the deformation capacity of the structure, followed by the inner angle of the cell element. Compared with the existing star zero Poisson 's ratio honeycomb structure, the RSRE structure proposed in this paper has a lower elastic modulus and stronger deformation ability. The reliability of the theoretical model and finite element simulation results was verified by experiments. In terms of structure preparation, a preparation method combining molding and winding processes was proposed for carbon-fiber-reinforced polymer reverse semi-re-entrant (CFRP+RSRE) honeycomb structures. Compared with the cutting method of laminated panels, the in-plane load-carrying capacity of the specimens prepared by this process increased by about 290%, and the failure displacement is improved by 160%.

     

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