• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Nature >Mechanical metamaterials at the theoretical limit of isotropic elastic stiffness
【24h】

Mechanical metamaterials at the theoretical limit of isotropic elastic stiffness

机译：各向同性弹性刚度理论极限下的机械超材料

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

A wide variety of high-performance applications(1) require materials for which shape control is maintained under substantial stress, and that have minimal density. Bio-inspired hexagonal and square honeycomb structures and lattice materials based on repeating unit cells composed of webs or trusses(2), when made from materials of high elastic stiffness and low density(3), represent some of the lightest, stiffest and strongest materials available today(4). Recent advances in 3D printing and automated assembly have enabled such complicated material geometries to be fabricated at low (and declining) cost. These mechanical metamaterials have properties that are a function of their mesoscale geometry as well as their constituents(3,5-12), leading to combinations of properties that are unobtainable in solid materials; however, a material geometry that achieves the theoretical upper bounds for isotropic elasticity and strain energy storage (the Hashin-Shtrikman upper bounds) has yet to be identified. Here we evaluate the manner in which strain energy distributes under load in a representative selection of material geometries, to identify the morphological features associated with high elastic performance. Using finite-element models, supported by analytical methods, and a heuristic optimization scheme, we identify a material geometry that achieves the Hashin-Shtrikman upper bounds on isotropic elastic stiffness. Previous work has focused on truss networks and anisotropic honeycombs, neither of which can achieve this theoretical limit(13). We find that stiff but well distributed networks of plates are required to transfer loads efficiently between neighbouring members. The resulting low-density mechanical metamaterials have many advantageous properties: their mesoscale geometry can facilitate large crushing strains with high energy absorption(2,14,15), optical bandgaps(16-19) and mechanically tunable acoustic bandgaps(20), high thermal insulation(21), buoyancy, and fluid storage and transport. Our relatively simple design can be manufactured using origami-like sheet folding(22) and bonding methods.
机译：各种各样的高性能应用（1）需要在很大的应力下保持形状控制并且密度最小的材料。生物启发的六角形和方形蜂窝结构以及基于由网或桁架组成的重复晶胞的格子材料（2），当由高弹性刚度和低密度的材料（3）制成时，代表了一些最轻，最硬和最坚固的材料今天可用（4）。 3D打印和自动组装的最新进展使这种复杂的材料几何形状能够以低廉（且不断下降的）成本进行制造。这些机械超材料的性能取决于其中尺度几何形状及其成分（3,5-12），从而导致在固体材料中无法获得的性能组合。但是，尚未确定达到各向同性弹性和应变能存储的理论上限的材料几何形状（Hashin-Shtrikman上限）。在这里，我们评估了在代表性的材料几何形状选择中应变能在载荷下的分布方式，以确定与高弹性性能相关的形态特征。使用分析方法支持的有限元模型和启发式优化方案，我们确定了实现各向同性弹性刚度的Hashin-Shtrikman上限的材料几何形状。以前的工作集中在桁架网络和各向异性蜂窝上，这两个都无法达到这一理论极限（13）。我们发现，需要刚性但分布良好的板状网络才能在相邻构件之间有效地传递载荷。所得的低密度机械超材料具有许多有利的性能：它们的中尺度几何形状可以促进具有高能量吸收（2,14,15），光学带隙（16-19）和机械可调声带隙（20），高热能的大破碎应变绝缘（21），浮力以及流体的存储和运输。我们相对简单的设计可以使用折纸样的折页（22）和粘合方法来制造。

著录项

  • 来源
    《Nature》 |2017年第7646期|533-537|共5页
  • 作者

    Berger J. B.; Wadley H. N. G.; Mcmeeking R. M.;

  • 作者单位

    Univ Calif, Dept Mat, Santa Barbara, CA 93106 USA|Univ Calif, Dept Mech Engn, Santa Barbara, CA 93106 USA;

    Univ Virginia, Sch Engn & Appl Sci, Dept Mat Sci & Engn, Charlottesville, VA 22904 USA;

    Univ Calif, Dept Mat, Santa Barbara, CA 93106 USA|Univ Calif, Dept Mech Engn, Santa Barbara, CA 93106 USA|Univ Aberdeen, Kings Coll, Sch Engn, Aberdeen AB24 3UE, Scotland|INM Leibniz Inst New Mat, Campus D22, D-66123 Saarbrucken, Germany;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号