Lightweight Mechanical Metamaterials with Tunable Negative Thermal Expansion
Lightweight Mechanical Metamaterials with Tunable Negative Thermal Expansion
复制标题
DOI：
10.1103/physrevlett.117.175901
复制
发表时间：
2016-10-21
影响因子：
8.6
通讯作者：
Fang, Nicholas X.
中科院分区：
文献类型：
--
作者：
Wang, Qiming;Jackson, Julie A.;Fang, Nicholas X.
漂浮在水面上的冰是自然界中负热膨胀（NTE）的一个重要表现。具有NTE的天然材料的有限例子刺激了工程结构的研究。以往对NTE结构的研究主要集中在理论设计上，在二维平面几何结构中的实验验证有限。在这项工作中，借助多材料投影微立体光刻，我们实验性地制造了轻质多材料晶格，该晶格在三个方向和170度的温度范围内表现出显着的负热膨胀。这种NTE是由具有不同热膨胀系数的材料组分的结构相互作用引起的。通过改变组成梁和几何布置之间的热膨胀系数差，可以在大范围内调谐NTE。我们的实验结果匹配定性与一个简单的标度律和定量与计算模型。
Ice floating on water is a great manifestation of negative thermal expansion (NTE) in nature. The limited examples of natural materials possessing NTE have stimulated research on engineered structures. Previous studies on NTE structures were mostly focused on theoretical design with limited experimental demonstration in two-dimensional planar geometries. In this work, aided with multimaterial projection microstereolithography, we experimentally fabricate lightweight multimaterial lattices that exhibit significant negative thermal expansion in three directions and over a temperature range of 170 degrees. Such NTE is induced by the structural interaction of material components with distinct thermal expansion coefficients. The NTE can be tuned over a large range by varying the thermal expansion coefficient difference between constituent beams and geometrical arrangements. Our experimental results match qualitatively with a simple scaling law and quantitatively with computational models.