S Rash Ahmadi - Assistant Professor, Faculty of Mechanical Engineering,Urumia University
Taher Azdast - Assistant Professor,Faculty of Mechanical Engineering,Urumia University
Saeed Hoseinpour Dash Atan - M.Sc. Student Faculty of Mechanical Engineering,Urmia University

A tribological analysis of deformations and stresses generated and their influence on surface failure in a coated surface loaded by line and point contact loading is presented.A plain strain finite element method (2D FEM) model has been developed for calculating the stresses and deformations for 20mmthick tungsten-carbon (WC) / Ductile tungsten (W) coated steel in line contact loading and a three dimensional finite element method (3D FEM) model has been developed for 5mmthick titanium nitride (TiN) coated steel surface in point contact loading. In both cases the stress field was obtained under normal and tangential loads. Because of high shear stress at the interfaces the interfacial shear stress may be the main reason for damage of the coating / substrate interfaces. When the indenter is slipping, tangential tensile stress is caused in coating behind the indenter, while in front of the indenter the tangential stress is compressive.

Coatings; Interface; Contact; Stress