Abstract Recently, much interest has been attracted in the graphene-assembled hollow nanospheres (GAHNs) because of outstanding multi-functional properties. This paper systematically explores the compressive mechanical behaviors and gas bearing capability of GAHNs by a coarse-grained molecular dynamics (CGMD) simulation combining with in-situ compressive test. It was found that the GAHNs possess excellent compressive elasticity (experimentally recoverable strain can reach ∼ 58 %). Under large compressive strain (>90 %), the GAHNs also display obvious plastic deformation owing to inter-layer slippage between graphene nanosheets. In addition, the morphology of force measurement tip (FMT) plays critical roles on the compressive failure modes of GAHNs. When FMT is sharp, it can pierce through the shell of GAHN, whereas the blunt one compels GAHN to collapse. The thermal expansion process of GAHNs was investigated by CGMD simulation. With the increase of ambient temperature, the internal pressure of GAHN increased until a crack appears. To further understand this expansion failure, an in-situ scratching experiment was designed and the tearing strength of shell of GAHN was estimated to be ∼ 748 MPa. This work provides an in-depth understanding on intrinsic mechanical properties of GAHNs and broadens their potential applications.

中文翻译：

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压缩下石墨烯组装的中空纳米球的力学行为和坍塌

摘要 近年来，石墨烯组装的空心纳米球（GAHNs）因其出色的多功能特性而受到广泛关注。本文通过粗粒分子动力学（CGMD）模拟结合原位压缩试验，系统地探讨了GAHNs的压缩力学行为和气体承载能力。发现 GAHN 具有优异的压缩弹性（实验可恢复应变可达 58%）。在大压缩应变（> 90％）下，由于石墨烯纳米片之间的层间滑动，GAHNs也表现出明显的塑性变形。此外，力测量尖端 (FMT) 的形态对 GAHN 的压缩破坏模式起着至关重要的作用。FMT锋利时，可以刺穿GAHN的外壳，而钝器迫使 GAHN 崩溃。通过CGMD模拟研究了GAHN的热膨胀过程。随着环境温度的升高，GAHN 的内部压力增加，直至出现裂纹。为了进一步了解这种膨胀失效，设计了原位划痕实验，估计 GAHN 外壳的撕裂强度约为 748 MPa。这项工作提供了对 GAHN 内在机械性能的深入理解，并拓宽了它们的潜在应用。设计了原位划痕实验，估计 GAHN 外壳的撕裂强度约为 748 MPa。这项工作提供了对 GAHN 内在机械性能的深入理解，并拓宽了它们的潜在应用。设计了原位划痕实验，估计 GAHN 外壳的撕裂强度约为 748 MPa。这项工作提供了对 GAHN 内在机械性能的深入理解，并拓宽了它们的潜在应用。