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用分子动力学方法对不同空位缺陷的扶手椅型与锯齿型单壁C纳米管杨氏弹性模量进行了计算和分析.结果表明:扶手椅型(5,5),(10,10)和锯齿型(9,0),(18,0)纳米管在无缺陷时其杨氏模量分别为948,901和804,860GPa.随管径的增大,扶手椅型和锯齿型单壁C纳米管弹性模量分别减小和增大,表现出完全不同的变化规律.随着C纳米管中单点空位缺陷的均匀增加,杨氏模量下降,当缺陷比率增加到一定程度时,杨氏模量下降骤然趋缓,形成一下降平台;双空位缺陷对C纳米管杨氏模量的影响与其分布方向有关;随单点空位缺陷间原子数的增加,在轴向上,杨氏模量下降到某一值小幅波动,而在周向上杨氏模量先下降,然后上升到某一稳定值.随两单点空位缺陷的空间距离进一步增大,杨氏模量又呈微降趋势.通过分子间σ键与π键特征及缺陷间近程电子云耦合作用规律与空位缺陷内部5-1DB缺陷的形成特点等理论对上述规律进行了分析.
The Young’s modulus of armchair and zigzag single-walled C nanotubes with different vacancy defects was calculated and analyzed by molecular dynamics method. The results showed that the elastic modulus of armchair (5,5), (10,10) and The Young’s modulus of the zigzag (9,0), (18,0) nanotubes without defects is 948, 901 and 804, 860 GPa respectively. With the increase of the diameter, the armchair and zigzag single-walled C nanotubes Modulus decreases and increases, respectively, showing completely different variation.With the uniform increase in single-site defects in C nanotubes, Young’s modulus decreases, when the defect ratio increases to a certain extent, the Young’s modulus The decrease of Young’s modulus of C nanotubes is related to its distribution direction. With the increase of atomic number between single vacancy defects, in the axial direction, the Young’s modulus decreases to The value of Young’s modulus decreases first and then rises to a certain value in the circumferential direction.With the further increase of the space distance of two single point vacancy defects, Inter-sigma bond and π bond characteristics and defects between the short-range electron cloud coupling rules and vacancies defects 5-1DB internal defects Into the above-described characteristics and other law theory analyzed.