Abstract Based on the bond-based peridynamic (BPD) method, a chirality-dependent peridynamic (CDPD) model is proposed for the fracture analysis of single layer graphene sheets (SLGS). The peridynamic (PD) parameters in the CDPD model are derived by analyzing the stress-strain relations of SLGS at atomic scale, and thus the CDPD model can provide a multiscale insight into the fracture analysis of SLGS with considering the effect of chirality. In order to increase the efficiency of CDPD simulations of large atomic-scale systems, a special coarse-grain (CG) technique is employed by considering the chiral structure of SLGS in the CDPD simulations. The effect of grid type, grid orientation and grid spacing on the numerical convergence is investigated. The proposed CDPD model is validated by comparing with the available molecular dynamics (MD) results, and the comparisons demonstrate the importance of considering the atomistic structure of SLGS when PD theory is applied in the fracture analysis because the chirality dominates the propagating directions of cracks. The crack propagations in SLGS with various chiralities are studied using the CDPD model. The numerical results indicate that the fracture of SLGS is significantly dependent on the chirality. Especially, examples of large-sized SLGS (750 nm × 750 nm) with about 20 million atoms in the corresponding fully atomistic systems demonstrate the applicability and effectiveness of the proposed CDPD model in the simulation of microscale structures of SLGS without loss of chiral features. To study such large systems is almost impractical for the fully atomistic simulation. This study also provides a significant insight for extending the PD model to the studies on chirality-related materials at microscale.

中文翻译：

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用于石墨烯片断裂分析的手性相关近场动力学模型

摘要 基于基于键的近场动力学（BPD）方法，提出了一种手性相关近场动力学（CDPD）模型用于单层石墨烯片（SLGS）的断裂分析。CDPD模型中的近场动力学（PD）参数是通过在原子尺度上分析SLGS的应力-应变关系得出的，因此CDPD模型可以为考虑手性影响的SLGS断裂分析提供多尺度洞察。为了提高大原子尺度系统CDPD模拟的效率，在CDPD模拟中考虑到SLGS的手征结构，采用了一种特殊的粗粒（CG）技术。研究了网格类型、网格方向和网格间距对数值收敛的影响。通过与可用的分子动力学 (MD) 结果进行比较，验证了所提出的 CDPD 模型，这些比较表明，当 PD 理论应用于断裂分析时，考虑 SLGS 原子结构的重要性，因为手性主导了裂纹的传播方向。使用 CDPD 模型研究了具有各种手性的 SLGS 中的裂纹扩展。数值结果表明SLGS的断裂显着依赖于手性。特别是，在相应的全原子系统中具有约 2000 万个原子的大尺寸 SLGS（750 nm × 750 nm）的例子证明了所提出的 CDPD 模型在模拟 SLGS 微尺度结构中的适用性和有效性，而不会丢失手性特征。研究如此大的系统对于完全原子模拟几乎是不切实际的。