Degradation of tires during intended usage

Abstract

There are several factors that influence the wear behaviour and service life of tires. Three of them are closely interrelated. They are the tire design, the operating conditions and the rubber material from which the tire is made. One of these factors is of utmost importance and less tangible. It is the choice of the appropriate elastomer, fillers, additives and also vulcanising agents to meet the specific requirements for a particular tire. There are expectations for noise, grip, rolling resistance and comfort, stability as well as safety at the limit (braking, cornering). Alongside this, the biggest challenge in tire development is to extend the lifetime of the tire by increasing resistance to tire degradation, which leads to cracking and wear, as much as possible to reduce overall costs and pollution and to increase sustainability to save resources. All these challenges are the focus of scientists and engineers as long as rubber is used for transport and locomotion of cars, trucks, etc. Moreover, it is difficult to establish correlations between available laboratory tests and real tire tests in the field. Therefore, this chapter gives a brief introduction to the theory of fracture mechanics of rubber leading to wear and shows why analyses with long known laboratory equipment predict a different wear behaviour of rubber than that of a tire in service. Finally, a broad overview is given of novel, high-performance technical measuring equipment with which very reliable experimental results could be obtained that correspond very well to the theory of fracture mechanics and much better to the real tire wear behaviour in service. The recent experimental research impressively demonstrates what a huge step has been taken in the meantime to improve the prediction of wear under specific operating conditions and the design and production for tailor-made tires.