Transient abrasion on a rubber sample due to highly dynamic contact conditions

Abstract Abrasive processes, primarily the local slip, are the dominant contributor to friction and wear of vehicle tires in service. The time history of forces accompanying acceleration, braking, and cornering in particular, lead constantly to changing contact conditions under the tire. Consequently, a laboratory test taking into account not only surface texture but also tire contact times (in the range of milliseconds) as well as realistic contact forces in a freely controllable temporal sequence is desirable. This paper presents the study of the dynamic contact between a rubber block and the abrasive surface at conditions close to those in a tire footprint. In our case, the test samples are a miniaturized tread block allowing to reproduce the intermittent tire contact including correct contact timings, pressure and friction coefficients in dependence on the driving maneuver to be tested. An analysis and comparison of friction and wear mechanisms for continuous contact and defined contact times is presented surpassing the characterization capabilities of DIN abrasion testers. Two different compounds with a variation of stiffness are examined. The grip and wear rates are analyzed and compared. It is shown that understanding the dominant mechanisms and quantifying tire tread friction and wear in detail require the consideration of realistic transient dynamics of a tire tread block impacting the road at each revolution of the tire.