2-DIMENSIONAL FINITE-ELEMENT ANALYSIS OF ELASTIC STRESSES IN DOUBLE-LAYER SYSTEMS UNDER COMBINED SURFACE NORMAL AND TANGENTIAL LOADS

This paper describes a continuation of previous work [1] which reported a finite-element analysis of the stress field in an elastic double-layer system owing to normal pressure distribution. Here we report a similar two-dimensional analysis of the effects of combined surface normal and tangential tractions, to simulate the stresses due to frictional sliding at the coated surface. The stresses have been computed for various values of the coating thickness, friction coefficient and one value of modulus ratio and contact half-width. It has been shown that for double-layer coatings with a decreasing modulus from the surface to the bulk, the surface maximum tensile stress at the trailing edge of the contact zone increases with the friction coefficient and decreases with the total thickness of the double layer. In addition, at the coating/substrate interface the effect of the friction coefficient becomes negligible for thick coatings. Finally, at the surface, the maximum shear stress, which also increases with the friction coefficient, is higher than that of a homogeneous material for the same friction coefficient. Conversely, in the substrate, the same stress is lower than that of a homogeneous material for the same friction coefficient.