Molecular dynamics simulation of indentation on nanocoated surfaces: A comparison between 3D and 2D plane strain models

Molecular dynamics studies with 3D model using spherical indenter and 2D plane strain model using cylindrical indenters revealed that the optimum coating thickness maximizing the hardness for a single layered nanocoating lies between 15 nm and 20 nm. The computational time is significantly lower for the plane strain model using cylindrical indenter than for the spherical indenter. However, the calculated hardness is different in both cases due to continuum and non-continuum effects. Continuum effects result in a reduction of hardness calculated by a cylindrical indenter, while the non-continuum effects result in an increase.