Abstract In this paper, a series of pull-out simulations of graphene are carried out to investigate the influence of two-dimensional (2D) geometric shapes of graphene nanosheet on the interfacial load transfer in graphene/PMMA nanocomposites by means of molecular dynamics (MD) simulation. Three common types of shapes, i.e. rectangle, trapezoid and sawtooth, are considered. It is found that the drastically improved pull-out force and interfacial shear strength is highly dependent on the 2D geometry and loading direction. By comparison of conventional rectangle-shaped graphene, trapezoidal- and sawtooth-shaped graphene effectively enhance the interfacial load transfer capability. Particularly, as a result of more effective steric-hindrance, pronounced enhancement in the pull-out force is observed when the loading direction is along the rostral-caudal direction of the trapezoidal graphene and the edge waviness of sawtooth-shaped graphene increases. Moreover, pull-out force model characterized by the interfacial shear force generation contacts and the resistance of the blocking zone are proposed to demonstrate the source of pull-out force and interfacial loading transfer mechanism for graphene with different 2D geometries. These findings are importance to better understand the alternative reinforcing mechanism of graphene with various geometric shapes and facilitate the development of mechanically robust graphene/polymer composites.

中文翻译：

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几何形状对石墨烯-PMMA 纳米复合材料中负载转移的作用

摘要 本文通过对石墨烯的一系列拉拔模拟，通过分子动力学（MD ） 模拟。考虑了三种常见类型的形状，即矩形、梯形和锯齿形。发现显着提高的拔出力和界面剪切强度高度依赖于二维几何形状和加载方向。与传统的矩形石墨烯相比，梯形和锯齿形石墨烯有效地增强了界面负载转移能力。特别是，由于更有效的位阻，当加载方向沿着梯形石墨烯的头尾方向并且锯齿形石墨烯的边缘波纹度增加时，观察到拉拔力的显着增强。此外，提出了以界面剪切力产生接触和阻塞区阻力为特征的拉拔力模型，以证明具有不同二维几何形状的石墨烯的拉拔力来源和界面载荷转移机制。这些发现对于更好地理解具有各种几何形状的石墨烯的替代增强机制和促进机械坚固的石墨烯/聚合物复合材料的开发具有重要意义。提出了以界面剪切力产生接触和阻塞区阻力为特征的拉拔力模型，以证明具有不同二维几何形状的石墨烯的拉拔力来源和界面载荷转移机制。这些发现对于更好地理解具有各种几何形状的石墨烯的替代增强机制和促进机械坚固的石墨烯/聚合物复合材料的开发具有重要意义。提出了以界面剪切力产生接触和阻塞区阻力为特征的拉拔力模型，以证明具有不同二维几何形状的石墨烯的拉拔力来源和界面载荷转移机制。这些发现对于更好地理解具有各种几何形状的石墨烯的替代增强机制和促进机械坚固的石墨烯/聚合物复合材料的开发具有重要意义。