Energy dissipative mechanism of graphene foam materials
Energy dissipative mechanism of graphene foam materials
复制标题
石墨烯泡沫材料的耗能机理
DOI：
10.1016/j.carbon.2018.02.085
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发表时间：
2018-06-01
期刊：
影响因子：
10.9
通讯作者：
Chen, Shaohua
中科院分区：
文献类型：
--
作者：
Wang, Chao;Pan, Douxing;Chen, Shaohua
石墨烯泡沫（GrF）是一种新型多孔材料，具有优异的多功能性，特别是耗散性，具有广泛的应用前景。然而，耗散机制和一些实验现象仍然知之甚少。在这里，系统的粗粒度分子动力学模拟（CGMD）进行研究这些问题。首次再现了在大应变加卸载和小应变循环荷载作用下的典型应力-应变关系。基于微观结构分析，提出了鳞片尺度下的三种主要耗散机制，波纹、滑动和撞击都没有被发现。进一步研究了循环次数、应变幅值和加载速率对耗散的影响。结果发现，在第一个加载周期的高得多的耗散基本上是由于激烈的薄片重排，这降低到一个较小的在随后的周期。此外，在第一个循环中，耗散几乎与应变大小成线性增加，而在随后的循环中，由于薄片堆叠结构，耗散以减小的斜率增加。对于给定的应变幅值，随着加载速率的增加，耗散将增强。这些结果加深了我们对石墨烯纤维耗散机制的理解，并将有助于开发新型多功能石墨烯基复合材料。(c)2018爱思唯尔有限公司版权所有
Graphene foam (GrF) is a new kind of multi-porous material with many potential applications owing to its excellent multi-functional properties, especially its dissipation capability. However, both the dissipative mechanism and some experimental phenomena remain poorly understood. Here, systematic coarse-grained molecular dynamic simulations (CGMD) are conducted to study these issues. The typical stress-strain relationships found in experiments under large-strain loading-unloading and small-strain cyclic load are first reproduced. Based on microstructure analysis, three major dissipative mechanisms in the scale of flakes, i.e., rippling, sliding and impacting, are uncovered. The influencing effects of cycle number, strain magnitude and loading rate on dissipation are further investigated. It is found that the much higher dissipation in the first loading cycle is essentially due to drastic flake rearrangements, which decreases to a smaller one in subsequent cycles. In addition, the dissipation increases almost linearly with the strain magnitude in the first cycle, while it increases with a reduced slope in subsequent cycles due to the flake stacking structures. For a given strain magnitude, the dissipation will be enhanced as the loading rate increases. These results deepen our understanding on the dissipative mechanism of GrFs and should be helpful for the development of novel multi-functional graphene-based composites. (c) 2018 Elsevier Ltd. All rights reserved.