Surface coatings and finite-element analysis of layered fretting contacts

Abstract

A fundamental, two-dimensional finite-element analysis (FEA) of a coated flat surface in a fretting contact with a flat-rounded punch is presented with a detailed listing of all modelling steps. A large number of basic results from a parametric study has been derived, focusing on the stress analysis and the effect of coatings on the life expectancy of the coated solid, without actually getting into the ambiguities of life evaluation. The parameters included in the study are the metallic coating thickness (5, 20, and 50 μm) and elastic modulus, the endurance limit of the coated substrate, and the normal and tangential loads applied. A summary of the stress analysis results is presented in a figure with nine diagrams, which assists the quick selection of the optimum parameter values for maximizing the coating performance and minimizing the risk of fatigue within the design limits used in the study. The model is realistic in that it does not use idealized load distributions in the fretting contact but actual geometrical solids of finite dimensions in contact under the normal operating conditions, letting the FEA software resolve the loads and stresses, which are subsequently validated.