An efficient method for evaluating the nanohardness of layer-configured materials by atomistic simulation

A new method for evaluating contact area and hardness is proposed for atomistic simulation of nanoindentation. The indenter is designed as a spherical virtual potential and atoms that enter the indenter are counted to evaluate the contact area. It is found that the nanohardness determined with the present method can be affected by the thermal activity of contact atoms, as well as the rigidity and dimensions of the virtual indenter. With the influencing factors carefully considered, molecular dynamics simulations employing the developed method are performed to investigate the indentation of carbon nanotubes (CNTs) along the radial direction and graphite sheets along the c-direction. It is found that the simulation results coincide well with available experimental findings, which demonstrates that the method is efficient for layer-configured nanomaterials such as CNTs and graphite crystal.