Engineer Energy Dissipation in 3D Graphene Nanolattice Via Reversible Snap-Through Instability
Engineer Energy Dissipation in 3D Graphene Nanolattice Via Reversible Snap-Through Instability
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DOI：
10.1115/1.4045544
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发表时间：
2019-12
期刊：
影响因子：
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通讯作者：
Bo Ni;Huajian Gao
中科院分区：
文献类型：
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作者：
Bo Ni;Huajian Gao
碳微纳晶格材料是指由微纳米级碳成分构成的三维结构超材料，通过实验和模拟，它具有超高的比强度、比刚度和广泛的变形能力等优异的力学性能。这些碳微/纳米晶格的延展性对于坚固的性能也很重要。在这项工作中，我们提出了一种新的设计，利用可逆的跃迁不稳定性来设计三维石墨烯纳米晶格的能量耗散。受柔性吸管壳层结构的启发，我们通过拓扑设计构造了一种石墨烯类似物，并通过分子动力学(MD)模拟论证了其相关的跳跃不稳定性。从一个晶胞出发，构建了一维稻草状碳纳米管(SCNT)和三维石墨烯纳米晶格。这些石墨烯纳米晶格具有多种稳定状态，并且是弹性可重构的。采用一维双稳单元链的理论模型来理解纳米晶格的集体形变行为。预测了具有有限磁滞回线的可逆假塑性行为，并通过分子动力学对其进行了进一步验证。通过这些新的能量耗散机制，三维石墨烯纳米晶格显示出良好的裂纹类缺陷容忍度，预计在一个加载周期内的比能量耗散接近233kJ/kg，而不会造成永久性损伤(比碳钢在失效时吸收的能量高一个数量级，16kJ/kg)。本研究提供了一种新型的三维碳纳米晶格在不累积损伤的情况下耗散能量和提高抗裂性的机理，拓宽了三维碳在能量吸收和可编程材料方面的应用前景。
Carbon micro/nanolattice materials, defined as three-dimensional (3D) architected metamaterials made of micro/nanoscale carbon constituents, have demonstrated exceptional mechanical properties, including ultrahigh specific strength, stiffness, and extensive deformability through experiments and simulations. The ductility of these carbon micro/nanolattices is also important for robust performance. In this work, we present a novel design of using reversible snap-through instability to engineer energy dissipation in 3D graphene nanolattices. Inspired by the shell structure of flexible straws, we construct a type of graphene counterpart via topological design and demonstrate its associated snap-through instability through molecular dynamics (MD) simulations. One-dimensional (1D) straw-like carbon nanotube (SCNT) and 3D graphene nanolattices are constructed from a unit cell. These graphene nanolattices possess multiple stable states and are elastically reconfigurable. A theoretical model of the 1D bi-stable element chain is adopted to understand the collective deformation behavior of the nanolattice. Reversible pseudoplastic behavior with a finite hysteresis loop is predicted and further validated via MD. Enhanced by these novel energy dissipation mechanisms, the 3D graphene nanolattice shows good tolerance of crack-like flaws and is predicted to approach a specific energy dissipation of 233 kJ/kg in a loading cycle with no permanent damage (one order higher than the energy absorbed by carbon steel at failure, 16 kJ/kg). This study provides a novel mechanism for 3D carbon nanolattice to dissipate energy with no accumulative damage and improve resistance to fracture, broadening the promising application of 3D carbon in energy absorption and programmable materials.