壳模型是研究碳纳米管力学行为时广泛采用的模型，但模型的等效厚度与碳管的物理厚度差别较大，长期存在争议.特别是当壳模型用于多壁碳纳米管分析时，层间作用需要额外考虑.提出碳纳米管的三明治式连续介质模型，用三层连续介质模拟一层碳管：内层模拟层内σ-键，两外侧层模拟层间范德华作用和π-键.该模型可直接利用有限元方法分析多壁碳纳米管的力学行为，且与已有分子动力学等计算结果比较，表明了该模型的有效性.
Shell model is widely used in studying the mechanical behavior of carbon nanotube, but the effective thickness and the physical thickness are greatly different. Especially the effects between two layers have to be considered in the study of multi-wall carbon nanotube. This paper proposed a carbon nanotube sandwich continuum model with three layers continuum to simulate one individual nanotube, the inner layer continuum simulate σ-bond, the two outer layers simulate π-bond and Van der waals force between two individual nanotubes. In this way finite element analysis could directly study mechanical behavior of multi-walled carbon nanotube. The model is proved valid by comparing the result with molecular dynamical (MD).
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