Elastic properties and pressure-induced structural transitions of single-walled carbon nanotubes
Elastic properties and pressure-induced structural transitions of single-walled carbon nanotubes
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DOI：
10.1103/physrevb.77.205437
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发表时间：
2008-05
影响因子：
3.7
通讯作者：
K. Liew;Yuzhou Sun
中科院分区：
文献类型：
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作者：
K. Liew;Yuzhou Sun
采用高阶梯度连续介质理论研究了单壁碳纳米管的力学性质和压力诱导结构转变。在对微尺度晶格矢量变形的近似中，同时考虑了一阶和二阶变形梯度，并将代表性单元的变形能与连续体的等效体积的变形能相等，从而得到了连续体弹性势，使得所建立的连续体本构模型更为合理.通过设置适当的方程作为从石墨片到初始未变形单壁碳纳米管的变形映射，通过最小化代表性单元的能量来获得单壁碳纳米管的弹性常数。单壁碳纳米管在轴对称载荷下的响应也可以通过改变设定的几何参数的值来获得。基于导出的本构模型，开发了一种计算方法来研究单壁碳纳米管在静水压力下的响应。
The mechanical properties and pressure-induced structural transitions of single-walled carbon nanotubes (SWCNTs) are studied in this paper in the theoretical scheme of the higher-order gradient continuum. Both the first- and second-order deformation gradients are involved in the approximation of the deformations of microscale lattice vectors, and the continuum elastic potential is obtained by equating the deformation energy of a representative cell with that of an equivalent volume of the continuum, and thus, the established continuum constitutive model is more reasonable. By setting an appropriate equation as the deformation map from a graphite sheet to an initial undeformed SWCNT, the elastic constants of SWCNTs are obtained by minimizing the energy of a representative cell. The response of SWCNTs under axis-symmetrical loadings can also be obtained by changing the values of the set geometrical parameters. Based on the derived constitutive model, a computational method is developed to study the response of SWCNTs under hydrostatic pressure.