A better approach to wear-rate representation in non-conformal contacts

Abstract

To usefully predict the service life of components employed in tribological applications, it is important that steady-state wear rates of the materials used to fabricate these components are available. With the increasing use of ceramics in sliding applications because of their superior wear resistance, the ready availability of appropriate steady-state wear rates becomes critical to the designers. A survey of the technical literature shows that most of the wear studies on ceramics have so far been conducted using non-conformal contact geometries such as ball-on-flat(s), ball-on-ball, cylinder-on-flat and so on. In such situations, the nominal contact area will increase and the nominal pressure will decrease with increasing time of wear testing; the measured wear rates are therefore expected to change with time: a non-steady-state situation. Erroneous conclusions would be drawn if wear-rate data obtained from different testing periods are compared. In this paper, a better approach to represent wear rates obtained from tests carried out using non-conformal contact geometries is proposed. In this approach, wear rates are presented in terms of the instantaneous pressure (rather than the applied load) at the point of wear-rate measurement.