ABSTRACT
The investigations on carbon nanotubes behavior have been mainly focused on the experimental description and molecular dynamics simulations such as classical molecular dynamics, tight-binding molecular dynamics and the ab initio method. However, researchers have been seeking more efficient computational methods with which it is possible to analyze the large scale of CNTs in more general manner. Yakobson et al. (1996) found that the continuum shell model could predict all changes of buckling patterns in the atomistic molecular-dynamics simulations. The analogousness of the cylindrical shell model and CNTs leads to the extensive application of the shell model for CNT analyses structure. Ru (2000 a, b, 2001) used a CM approach and simulated the effect of van der Waals forces by applying a uniformly distributed pressure field on a wall, the pressure field was adjusted so as to give the same resultant force on each wall of the tube. It is verified that the mechanical responses of CNTs can be efficiently and reasonably predicted by the shell model provided that the parameters, such as Young’s modulus and effective wall thickness, are judiciously adopted. Wang et al. (2006) studied buckling of double-walled carbon nanotubes under axial loads, by modeling CNTs using solid shell elements. Han et al. (2003, 2006) studied the torsional buckling of a DWNT and MWNT embedded in an elastic medium. Han et al. (2005) also studied the bending instability of double-walled carbon nanotubes.Yao & Han (2006, 2007) studied the thermal effect on axially compressed and torsional buckling of a multi-walled carbon nanotube. Some conclusions are drawn that at low and room temperature the critical load for infinitesimal buckling of a multi-walled carbon nanotube increase as the value of temperature change increases, while at high temperature the critical load for infinitesimal buckling of a multi-walled carbon nanotube decrease as the value of temperature change increases. Nonlinear postbuckling behavior of carbon nanotubes under
large strain is significant and is paid great attention by some researchers (Wang et al. 2005), Leung et al. 2006). The torsional postbuckling behavior of singlewalled or multi-walled carbon nanotubes has been studied in details by Yiao & Han (2008).
