The Strain Rate Effect of Perfect and Defective Single-Walled Carbon Nanotubes Under Axial Compression

摘要

Different effects of three typical categories of defect on the axial buckling properties of single-walled carbon nanotubes are investigated. Classical molecular dynamics is used to simulate the buckling behavior of both perfect and defective armchair single-walled carbon nanotubes under axial compression at different loading rates. Simulation results show that the buckling behavior of defective tubes is loading-rate dependent regularly while the mechanical properties of the perfect tube do not change much as the loading rate varies. The in-plane stiffness increases as the tubes are compressed which means the single-walled carbon nanotubes do not deform linearly before they buckle. The mechanical properties of single-walled carbon nanotubes are easily influenced by the defects, but the harmful effects of defects do not simply depend on the size of the defective area. The critical buckling loads of single-walled carbon nanotubes decrease sharply due to the defects, and the influence is strongly related to the buckling modes which specifically differ from each other due to the different defect structures. The effective Young's modulus is also slightly adversely affected with the effect mainly depending on how many axial zigzag chains of C—C bonds are broken in the defective area.