This work focuses on the effects of crack free friction on Mode Ⅱ stress intensity factors, KⅡ, for a vertical surface crack in a two-dimensional finite element model of TiN/steel subject to rolling contact. Results indicate that maximum KⅡ values, which occur when the load is adjacent to the crack, may be significantly reduced in the presence of crack face friction. The reduction is more significant for thick coatings than for thin. Crack extension and increased layer thickness result in increased KⅡ values. The effect of crack face friction on compressive KⅠ values appears negligible. Comparative results are presented for MoS₂/steel and diamond-like carbon(DLC)/Ti systems.
