Mao Jia-Jia, Liu Shuang, Li Lili, Chen Jie
Beijing Key Laboratory of Nonlinear Vibrations and Strength of Mechanical Structures, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China.
School of Materials Science and Engineering, East China Jiaotong University, Nanchang 330013, China.
Nanomaterials (Basel). 2022 Jul 14;12(14):2407. doi: 10.3390/nano12142407.
As deformation and defects are inevitable during the manufacture and service of graphene resonators, comprehensive molecular dynamic (MD) simulations are performed to investigate the vibrational properties of the defective single-layer graphene sheets (SLGSs) during tension. Perfect SLGSs, SLGSs with single vacancy, SLGSs with low-concentration vacancies, and SLGSs with high-concentration vacancies are considered, respectively. The frequencies of the perfect and defective SLGSs at different stretching stages are investigated in detail. The effects of different external forces are also taken into account to study the vibration properties of the defective SLGSs. Results show that the perfect and defective SLGSs both successively perform four stages, i.e., the elastic stage, the yield stage, the hardening stage, and the fracture stage during stretching, and the elastic properties of the SLGSs are insensitive to the vacancy defects, while the ultimate strain is noticeably reduced by the vacancies. The single vacancy has no effect on the vibration properties of SLGS, while the frequency decreases with the increasing vacancy concentration for SLGS at the elastic stage. The frequency of yielded SLGS with a certain vacancy concentration is almost constant even with a varying external force.
由于在石墨烯谐振器的制造和使用过程中，变形和缺陷不可避免，因此进行了全面的分子动力学（MD）模拟，以研究有缺陷的单层石墨烯片（SLGS）在拉伸过程中的振动特性。分别考虑了完美的SLGS、具有单空位的SLGS、具有低浓度空位的SLGS和具有高浓度空位的SLGS。详细研究了完美和有缺陷的SLGS在不同拉伸阶段的频率。还考虑了不同外力的影响，以研究有缺陷的SLGS的振动特性。结果表明，完美和有缺陷的SLGS在拉伸过程中都依次经历四个阶段，即弹性阶段、屈服阶段、强化阶段和断裂阶段，并且SLGS的弹性性能对空位缺陷不敏感，而空位会显著降低极限应变。单空位对SLGS的振动性能没有影响，而在弹性阶段，SLGS的频率随着空位浓度的增加而降低。具有一定空位浓度的屈服SLGS的频率即使在外力变化时也几乎保持不变。
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