“Y”型、竹节型与直纳米碳管的力学特性研究

采用基于BrennerREAO(reactiveempiricalbondorder)势的分子动力学方法,模拟了“Y”型、竹节型与直纳米碳管的拉伸过程。结合有限元分析,对比并讨论了“Y”型、竹节型纳米碳管与直纳米碳管拉伸力学性能的差异。研究结果表明,拉伸“Y”型、竹节型纳米碳管的屈服与断裂均发生在其粗管与细管过渡的“应力集中”部位;“应力集中”致使“Y”型、竹节型纳米碳管的抗拉强度与韧性明显低于直纳米碳管;然而,“Y”型、竹节型碳管的弹性模量依然与直纳米碳管相当。

Molecular Dynamics Simulations of "Y"-Shaped, Bamboo-Shaped, and Straight Carbon Nanotubes Under Tensile Load

Brenner REAO potential based MD(molecular dynamics)simulations were performed on"Y"-shaped,bamboo-shaped and straight carbon nanotubes under tensile load. According to the obtained MD results,as well as the corresponding FE(finite element)calculations on the nanotubes,mechanical properties of these carbon tubes were compared and analyzed. The study showed that,yielding and fracture of"Y"-shaped and bamboo-shaped carbon nanotubes result from the"stress concentration"at the junctures of thin and thick nanotubes,and"Y"-shaped and bamboo-shaped carbon nanotubes had obviously lower tensile strength and toughness than straight nanotubes had. However,"Y"-shaped,bamboo-shaped and straight carbon nanotubes seemed to have no evident difference between their elastic modulus.