一維奈米碳結構之機械特性研究

摘要本研究利用分子動力學來模擬C60奈米管的壓痕特性及奈米碳管的共振頻率。碳原子間的作用力是利用Tersoff勢能來描述。C60、奈米碳管及探針的非鍵結力則是利用Lennard-Jones勢能描述。奈米壓痕的模擬結果顯示出當系統溫度增加時，其最大負載力會隨系統溫度增加而降低。而楊氏模數、塑性能及彈性能也隨著系統溫度增加而呈現遞減的趨勢。另外在本研究中加入了單臂奈米碳管與雙臂奈米碳管的機械特性來與C60奈米管的機械特性做比較。結果顯示雙臂奈米碳管剛性最強而單臂奈米碳管最差。奈米碳管共振頻率的結果顯示當系統溫度增加時，其共振頻率會隨著溫度增加而降低，當奈米碳管長度與直徑比增加時其共振頻率會降低，而比較短的奈米碳管擁有比較佳的共振頻率。最後將C60奈米管的機械特性與奈米碳管的共振頻率作一系列的探討。

關鍵字

分子動力學；奈米碳管；奈米壓痕；共振頻率；機械特性

並列摘要

Abstract This study used molecular dynamics to simulate the indentation properties of C60 filled in carbon nanotube and the resonator frequencies of carbon nanotubes. The interaction forces of carbon atoms was described by Tersoff’s potential energy. The nonbonding force of C60, carbon nanotube and probe was described by Lennard-Jones potential energy. The results of nanoindentation showed that when the system temperature increased, the maximum load was decreased. The Young’s modulus, plastic energy and elastictic energy were decreased with the raising system temperature. In addition, the mechanic properties of single carbon nanotube (SWCNT) and double wall carbon nanotube (DWCNT) were compared with the mechanic properties of C60 filled in carbon nanotube. That the results showed the stiffness of double wall carbon nanotube was the best, and the stiffness of single wall carbon nanotube was the worst. In resonator frequencies of carbon nanotubes processes, that the results showed when the system temperature increased, the resonator frequencies were decreased, and when the ratio of length and diameter increased, the resonator frequencies were decreased, the smaller carbon nanotube have excellent resonator frequency. A summary was made a serious of discussion with the mechanical properties of C60 filled in carbon nanotubes and the resonator frequencies of carbon nanotubes.