Size effect on mechanical properties of carbon nanotube X-junctions

Carbon nanotube X-junctions of various diameters are investigated for the size effect on their mechanical properties by molecular dynamics simulation. The simulation results show that their mechanical properties, including the Young’s modulus, yield stress and yield strain, depend on the junction diameter. There are two types of deformation mechanisms for X-junctions under tensile load.

► Carbon nanotube X-junctions of various diameters are investigated for the size effect on their mechanical properties by molecular dynamics simulation.
► The results show that the Young’s modulus, yield stress and yield strain are smaller than those corresponding to pure SWCNTs due to the introduction of defects at the junction regions.
► These mechanical properties also decrease with increase in junction diameter for both odd type junctions and even type junctions.
► The majority of simulation data shows that both the yield strain and yield stress along Z-axis are larger than those along Y-axis for all junctions.
► There are two fracture mechanisms, i.e. shear fracture and necking for carbon nanotube junctions under tensile loading.