This paper reviews the mechanical properties of graphene with particular attention to what is established and what is still uncertain. It clarifies the thickness and the elastic constants, and by also considering also phonon frequencies, it argues that “best values” come from graphite, when available. Properties not available from graphite include bending stiffness; this can be determined from studies of carbon nanotubes as well as graphene. In many ways, nanotubes provide access to fundamental properties of graphene, not least because they are the only form of graphene that can be unsupported (unstrained) in vacuum. Environmental effects are considered, including both interactions with substrates and with other solid and liquid media, which may affect the geometrical parameters defining graphene and associated elastic constants. Major uncertainties persist whether slipping or sticking dominates experimental observation, both between graphene and solid media, and between the layers of bilayer and multilayer graphene. The paper concludes with a short discussion of continuum and atomistic models of graphene.

中文翻译：

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石墨烯的机械性能

本文回顾了石墨烯的机械性能，特别关注已确定和尚不确定的内容。它阐明了厚度和弹性常数，并且还考虑了声子频率，认为“最佳值”来自石墨（如果可用）。石墨不具备的特性包括弯曲刚度；这可以通过对碳纳米管和石墨烯的研究来确定。在许多方面，纳米管提供了获得石墨烯基本特性的途径，尤其是因为它们是唯一一种可以在真空中不受支撑（不受约束）的石墨烯形式。环境影响被考虑在内，包括与基材和其他固体和液体介质的相互作用，这可能会影响定义石墨烯和相关弹性常数的几何参数。无论是在石墨烯和固体介质之间，还是在双层和多层石墨烯的层之间，主要的不确定性仍然存在，无论是滑动还是粘附主导实验观察。本文最后简要讨论了石墨烯的连续介质和原子模型。