Wang Shuai, Wang Chao, Khan Muhammad Bilal, Chen Shaohua
Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing, 100081, People's Republic of China.
Beijing Key Laboratory of Lightweight Multi-Functional Composite Materials and Structures, Beijing Institute of Technology, Beijing, 100081, People's Republic of China.
Nanotechnology. 2021 Jun 3;32(34). doi: 10.1088/1361-6528/ac020c.
Many experiments have shown that carbon nanotube-coated (CNT-coated) graphene foam (CCGF) has specific mechanical properties, which further expand the application of graphene foam materials in many advanced fields. To reveal the microscopic deformation mechanism of CCGF under uniaxial compression and the main factors affecting their mechanical properties, numerical experiments based on the coarse-grained molecular dynamics method are systematically carried out in this paper. It is found that the relative stiffness of CNTs and graphene flakes seriously affects the microscopic deformation mechanism and strain distribution in CCGFs. The bar reinforcing mechanism will dominate the microstructural deformation in CCGFs composed of relatively soft graphene flakes, while the microstructural deformation in those composed of stiff graphene flakes will be dominated by the mechanical locking mechanism. The effects of CNT fraction, distribution of CNTs on graphene flakes, the thickness of graphene flakes, and the adhesion strength between CNTs and graphene flakes on the initial and intermediate moduli of foam materials are further studied in detail. The results of this paper should be helpful for a deep understanding of the mechanical properties of CCGF materials and the optimization design of microstructures in advanced graphene-based composites.
许多实验表明，碳纳米管包覆（CNT包覆）的石墨烯泡沫（CCGF）具有特定的力学性能，这进一步拓展了石墨烯泡沫材料在许多先进领域的应用。为揭示CCGF在单轴压缩下的微观变形机制以及影响其力学性能的主要因素，本文基于粗粒度分子动力学方法系统地开展了数值实验。研究发现，碳纳米管与石墨烯片的相对刚度严重影响CCGF中的微观变形机制和应变分布。在由相对较软的石墨烯片组成的CCGF中，棒增强机制将主导微观结构变形，而在由刚性石墨烯片组成的CCGF中，微观结构变形将由机械锁定机制主导。进一步详细研究了碳纳米管含量、碳纳米管在石墨烯片上的分布、石墨烯片的厚度以及碳纳米管与石墨烯片之间的粘附强度对泡沫材料初始模量和中间模量的影响。本文的研究结果有助于深入理解CCGF材料的力学性能以及先进石墨烯基复合材料微观结构的优化设计。
