Twisting is a simple and effective method for assembling individual carbon nanotubes (CNTs) into high-strength, tough, and continuous CNT yarns. However, the unexpectedly low stretching performance of the resulting carbon nanotube bundle (CNTB) structures is a problem that must be resolved. In this study, we investigated the impact of twisting on the structure and stretching performance of CNTBs through molecular dynamics (MD) simulations while considering the presence of disclinations within the CNTB structure. We found that disclinations nucleate in twisted CNTBs, and the longer the disclination line in CNTBs, the lower the Young's modulus. The presence of disclination lines in the twisted CNTBs may be an important reason for the decrease in the tensile properties of the CNT yarns. Although the theoretical equations in textile field can be applied to describe the mechanical properties of CNT yarns, there are significant relative errors between the equations and the MD simulation results presented herein. Therefore, we revised the equations based on the simulation results to reduce the relative error for seven-layer CNTBs to less than 10 %. This paper provides new insights into the low tensile performance of CNT yarns and offers potential guidance for the production of high-performance CNT yarns through twisting.

中文翻译：

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扭转载荷下碳纳米管束结构中向错的成核


加捻是将单个碳纳米管 (CNT) 组装成高强度、坚韧且连续的 CNT 纱线的简单而有效的方法。然而，所得碳纳米管束（CNTB）结构的拉伸性能出乎意料地低，这是必须解决的问题。在本研究中，我们通过分子动力学（MD）模拟研究了扭曲对CNTB结构和拉伸性能的影响，同时考虑了CNTB结构中向错的存在。我们发现向错在扭曲的CNTB中成核，并且CNTB中的向错线越长，杨氏模量越低。加捻CNTB中向错线的存在可能是CNT纱线拉伸性能下降的重要原因。虽然纺织领域的理论方程可以用来描述碳纳米管纱线的力学性能，但本文提出的方程与MD模拟结果之间存在显着的相对误差。因此，我们根据仿真结果修改了方程，将七层CNTB的相对误差降低到10%以下。本文为碳纳米管纱线的低拉伸性能提供了新的见解，并为通过加捻生产高性能碳纳米管纱线提供了潜在的指导。