Comparison of mechanical behaviors between cracked functionally graded GPL- and CNT-reinforced composite plates

The nanocomposite structures reinforced with carbon nanotubes (CNTs) and graphene platelets (GPLs) in the functionally graded distributions have been intensively studied as an advanced composite structure. However, these studies were conducted for each nanocomposite without comparison, assuming that the structure was not damaged without cracks. In this context, the present study intends to compare the mechanical behaviors between the CNT- and GPL-reinforced composite plates with and without crack in the linear and nonlinear ranges. The numerical method is developed in the framework of 2-D extended natural element method (XNEM) in which the crack line is represented by the phase-field formulation (PFF) and the crackinduced singularity is captured by the crack-tip singular functions. The developed numerical method is validated through the benchmark test, and the mechanical responses of the CNT- and GPL-reinforced composite plates are compared with respect to the total volume fraction and the distribution pattern of nanofillers, the crack angle and CNT alignment, and the boundary condition. The numerical results reveal that the developed numerical method accurately predicts the linear and nonlinear mechanical responses of cracked nanocomposite plates. And, the comparative numerical results found that the GPL-reinforced composite plate is much stiffer than the CNT-reinforced one which exhibits the remarkable dependence on the CNT alignment.