Fretting Contact of Two Dissimilar Elastic Bodies with Functionally Graded Coatings

Abstract

A two-dimensional fretting contact problem involving normal and tangential loading of two dissimilar elastic bodies with functionally graded coatings is analyzed. The bodies are first brought into contact by a monotonically increasing normal load and then a cycled tangential load is applied with the normal load held constant. Friction with a finite coefficient is assumed between the contact surfaces. The linear multi-layered model is used to model functionally graded coating with arbitrarily varying shear modulus and constant Poisson's ratio under plane strain deformation. With the use of the transfer matrix method and Fourier integral transform technique, the problem is reduced to a set of Cauchy singular integral equations which are solved numerically. An iterative method is developed to determine the stick/slip region and contact tractions. The numerical results show that the functionally graded coating on the harder body can lower the fretting contact stresses and thus improve the resistance to the fretting contact damage, and that in comparison with a homogeneous coating, a functionally graded coating can eliminate the interfacial stress concentration induced by material property mismatch.