Molecular simulations of the carbon nanotubes intramolecular junctions under mechanical loading

In this paper, mechanical responses of the carbon nanotubes (CNTs) intramolecular junctions (IMJs) under three generic modes of mechanical loadings - tension, compression, and torsion have been studied using molecular dynamics simulations. (5,5)-(10,0), (7,7)-(14,0), (10,10)-(20,0) armchair-zigzag and (8,0)-(6,0) zigzag-zigzag IMJs have been simulated by connecting two constituent CNTs with pentagon and heptagon rings. Classical molecular dynamics based on the velocity-Verlet algorithm has been used to solve the Newtonian equation of motion and carbon-carbon interaction in the CNT has been modeled by the Brenner potential. Mechanical properties, particularly stiffness and maximum force/torque and failure modes for different loading conditions are studied. Simulation results show that stiffness of the IMJ falls between those of the constituent CNTs. Compressive failure load of the IMJ is lower than either of the constituent CNTs. However, failure loads and damage modes of the IMJs under tensile and torsional loadings depend on the transition region in the IMJs. (C) 2013 Elsevier B.V. All rights reserved.