Wang Lianchao, Martínez Julio A Iglesias, Ulliac Gwenn, Wang Bing, Laude Vincent, Kadic Muamer
National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, 150001, Harbin, P.R. China.
Université Franche-Comté, CNRS, Institut FEMTO-ST, Besançon, 25000, France.
Nat Commun. 2023 Aug 8;14(1):4778. doi: 10.1038/s41467-023-40493-6.
Non-Newtonian liquids are characterized by stress and velocity-dependent dynamical response. In elasticity, and in particular, in the field of phononics, reciprocity in the equations acts against obtaining a directional response for passive media. Active stimuli-responsive materials have been conceived to overcome it. Significantly, Milton and Willis have shown theoretically in 2007 that quasi-rigid bodies containing masses at resonance can display a very rich dynamical behavior, hence opening a route toward the design of non-reciprocal and non-Newtonian metamaterials. In this paper, we design a solid structure that displays unidirectional shock resistance, thus going beyond Newton's second law in analogy to non-Newtonian fluids. We design the mechanical metamaterial with finite element analysis and fabricate it using three-dimensional printing at the centimetric scale (with fused deposition modeling) and at the micrometric scale (with two-photon lithography). The non-Newtonian elastic response is measured via dynamical velocity-dependent experiments. Reversing the direction of the impact, we further highlight the intrinsic non-reciprocal response.
非牛顿液体的特征在于其动力学响应依赖于应力和速度。在弹性领域，特别是在声子学领域，方程中的互易性不利于获得被动介质的定向响应。人们设想了有源刺激响应材料来克服这一问题。值得注意的是，米尔顿和威利斯在2007年从理论上表明，在共振时包含质量的准刚体可以表现出非常丰富的动力学行为，从而为非互易和非牛顿超材料的设计开辟了一条途径。在本文中，我们设计了一种具有单向抗冲击性的固体结构，从而类似于非牛顿流体超越了牛顿第二定律。我们使用有限元分析设计这种机械超材料，并通过厘米级（使用熔融沉积建模）和微米级（使用双光子光刻）的三维打印来制造它。通过依赖于动态速度的实验来测量非牛顿弹性响应。通过反转冲击方向，我们进一步突出了其固有的非互易响应。
