| The elastic contact between two spherical asperities in sliding motion produces a contact stress field in the asperities and a frictional heat source at the contact region. The influences of the frictional heat on the stress field and on the yield condition of the asperity, which is stationary relative to the heat source, are investigated.The temperature distribution and the corresponding thermal stress field are determined. The yield condition of the combined thermal and isothermal stresses under a temperature-dependent yield criterion is investigated. Under the assumption that material yielding on the surface is the mechanism producing wear, a thermomechanical wear theory is proposed.A wear map can be constructed from the theory. Tribological operating conditions can be specified as an operating point in the map. Three regions can be identified in the map: no-wear, conditional-wear and immediate-wear regions. Depending upon the region in which the operating point is located, the wear condition for the given operation can be determined. An approach of wear control is suggested: maintain the operation in the no-wear region to eliminate the thermomechanical wear.The result of applying the theory, which is a single-contact model, to a real sliding contact, multiple-contact, by using a random process is presented. |
