Hysteresis Losses in the Friction of Lubricated Rubber

Abstract

Abstract The main point brought out in this paper is that when well lubricated rubber surfaces slide over hard protuberances the major part of the resistance to sliding may well arise from hysteretic losses in the rubber itself. Any factor, such as temperature or frequency of deformation, which affects the hysteresis losses will have a corresponding effect on the friction. This suggests that the resistance to sliding on wet or slippery road surfaces may be considerably increased by using a tire rubber which maintains a high hysteretic loss over the range of speeds and temperatures developed during operation. In order to reduce the tendency to overheat a duplex structure is suggested in which the body of the tire has low losses whilst the tread has high losses. The free rolling friction of the tire may be kept low both by modifying the geometry of the tire to give a long narrow band of contact with the road surface, and by using fine texture protuberances on the roadway. The author is aware of the fact that he has drawn rather far-reaching practical conclusions from simple laboratory experiments; nevertheless there is an increasing body of evidence supporting the view that the idea of hysteretic losses is an important one in enabling us to understand and indeed to control the friction of rubber on slippery surfaces. It should be possible, perhaps by working on these lines for the tire manufacturer and the highway engineer, starting from fundamental principles, to produce a combination of tire properties and highway characteristics that will ensure a greater measure of skid resistance on wet or greasy roadways.