Stress distribution of a coated film with an interlayer under elastohydrodynamic lubrication conditions

Abstract

Abstract

In recent years, there have been advances in techniques for improving sliding performance by using coated films possessing superior tribological properties to reduce failure of mechanical elements. Those techniques are often used under severe conditions, such as elastohydrodynamic lubrication (EHL). In this paper, to devise the optimum design of a coated film with an interlayer, the stresses generated in such a coated film are analysed by using a three-dimensional numerical analysis method, and the strength of the film is evaluated numerically. As a result, it is shown that, when the ratio of the modulus of elasticity of the coated film, E_c, to that of the substrate, E_s, is 0.50, it is preferable that the thicknesses of the coated film and the interlayer be larger, and that the modulus of elasticity of the interlayer range from that of the coated film to that of the substrate. Furthermore, it is shown that in the case of E_c/E_s=2.00, it is preferable to have a thicker interlayer irrespective of the values of the moduli of elasticity of the coated film and the interlayer.