A model for elastic-plastic contact of ellipsoids with work-hardening effect

Based on experiments, a semi-empirical model is proposed for the elastic-pl astic contact of ellipsoids. The model predicts the total contact area of t wo separated parts, namely, the plastic and elastic parts. The prediction o f the plastic area is achieved by an empirical formula, in which, a represe ntative contact stress is, in terms of the plastic contact area, in the for m of a power law. The power index, satisfying the relation between the repr esentative contact stress and the plastic contact area, is obtained with th e flattened areas of a contacting body completely unloaded from specified l oads in the experiment. The power index is also called the work-hardening i ndex. The elastic part of the contact area is obtained from the Hertzian co ntact result. With such a model, when either the nominal interference (or a pproach) between two metallic bodies or the normal load on the contact is k nown, all other quantities, such as total load or interference, plastic and elastic parts of contact area, etc., can be found. In order to confirm the model, a series of contact experiments for different metallic ellipsoids w as conducted. It was found that the results from the model agree with the e xperiments very well.