Li Weichen, Sigmund Ole, Zhang Xiaojia Shelly
Department of Civil and Environmental Engineering, University of Illinois Urbana-Champaign, 205 North Mathews Ave, Urbana, IL, 61801, USA.
Department of Civil and Mechanical Engineering, Technical University of Denmark, Koppels Allé, Building 404, Kongens Lyngby, 2800, Denmark.
Nat Commun. 2024 Jul 15;15(1):5527. doi: 10.1038/s41467-024-49630-1.
Fourier's law dictates that heat flows from warm to cold. Nevertheless, devices can be tailored to cloak obstacles or even reverse the heat flow. Mathematical transformation yields closed-form equations for graded, highly anisotropic thermal metamaterial distributions needed for obtaining such functionalities. For simple geometries, devices can be realized by regular conductor distributions; however, for complex geometries, physical realizations have so far been challenging, and sub-optimal solutions have been obtained by expensive numerical approaches. Here we suggest a straightforward and highly efficient analytical de-homogenization approach that uses optimal multi-rank laminates to provide closed-form solutions for any imaginable thermal manipulation device. We create thermal cloaks, rotators, and concentrators in complex domains with close-to-optimal performance and esthetic elegance. The devices are fabricated using metal 3D printing, and their omnidirectional thermal functionalities are investigated numerically and validated experimentally. The analytical approach enables next-generation free-form thermal meta-devices with efficient synthesis, near-optimal performance, and concise patterns.
傅里叶定律表明热量从高温流向低温。然而，可以定制设备来掩盖障碍物，甚至逆转热流。数学变换为获得此类功能所需的渐变、高度各向异性的热超材料分布产生了封闭形式的方程。对于简单几何形状，设备可以通过规则的导体分布来实现；然而，对于复杂几何形状，到目前为止物理实现一直具有挑战性，并且通过昂贵的数值方法获得了次优解决方案。在这里，我们提出了一种直接且高效的解析去均匀化方法，该方法使用最优多秩层压板为任何可想象的热操纵设备提供封闭形式的解决方案。我们在复杂域中创建了具有接近最优性能和美学优雅性的热斗篷、旋转器和集中器。这些设备使用金属3D打印制造，并对其全向热功能进行了数值研究和实验验证。这种解析方法能够实现具有高效合成、接近最优性能和简洁图案的下一代自由形式热超材料设备。
