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

To usefully predict the service life of components employed in tribological applications, it is important that steady-state wear rates of the material s used to fabricate these components are available. With the increasing use of ceramics in sliding applications because of their superior wear resista nce, 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-c onformal 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 incre ase and the nominal pressure will decrease with increasing time of wear tes ting; the measured wear rates are therefore expected to change with time: a non-steady-state situation. Erroneous conclusions would be drawn if wear-r ate data obtained from different testing periods are compared. In this pape r, a better approach to represent wear rates obtained from tests carried ou t using non-conformal contact geometries is proposed. In this approach, wea r rates are presented in terms of the instantaneous pressure (rather than t he applied load) at the point of wear-rate measurement. (C) 1999 Elsevier S cience S.A. All rights reserved.