Strain rate effects on the mechanical properties of graphene sheets (GSs) contain randomly distributed defects investigated by molecular dynamics simulations, and the results have been discussed. The strain rate has a significant effect on the tensile strength, while fracture strain and failure mechanism of GSs and elastic modulus are insensitive to the strain rate. At room temperature of 300 K, GSs without defects show that brittle failure is at a low strain rate and linear hardening is at a high strain rate. The strain rate is higher, the GSs are harder. However, GSs with a large number of randomly distributed defects only show brittle failure under high temperature. The tensile strength and fracture strain increase with the strain rate increasing. The tensile strength of GSs without defects has a linear relation to the logarithm of the strain rate, but the GSs with defects do not exhibit this phenomenon because the defects are sensitive to the strain rate. The present study provides a theoretical optimization method for the preparation and performance of GSs.

中文翻译：

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含随机分布缺陷石墨烯片力学性能的应变率效应研究

应变率对石墨烯片 (GS) 机械性能的影响包含通过分子动力学模拟研究的随机分布的缺陷，并且已经讨论了结果。应变速率对拉伸强度有显着影响，而GSs的断裂应变和失效机制和弹性模量对应变速率不敏感。在 300 K 的室温下，没有缺陷的 GS 表明脆性破坏处于低应变率，而线性硬化处于高应变率。应变率越高，GS 越硬。然而，具有大量随机分布缺陷的 GS 仅在高温下表现出脆性破坏。拉伸强度和断裂应变随着应变速率的增加而增加。没有缺陷的 GSs 的拉伸强度与应变率的对数呈线性关系，但有缺陷的 GSs 不会出现这种现象，因为缺陷对应变率很敏感。本研究为GSs的制备和性能提供了一种理论优化方法。