A Novel Method for Evaluation of Tyre Structural Durability Performance

In a vehicle, tyre is a safety critical component and hence its structural durability performance is of paramount interest to the vehicle users. Therefore, ensuring durability performance is an essential criterion to prevent fatal accidents, unusual road delays, etc. Generally, tyre structural durability or endurance performance is ascertained in the indoor laboratory by freely rotating the tyre on a smooth steel road wheel. The tyre runs straight ahead at a fixed speed and load is applied incrementally till failure or pre-defined level (fixed load step or fixed running kilometer). Although the test conditions used in these type of tests take care of certain parameters but it requires inclusion of additional parameters to simulate more realistic tyre operational conditions. One such parameter is camber angle in a vehicle, which is kept non-zero values (positive or negative) to achieve desired vehicle handling performance. Further, the roadways are also having in-built camber to facilitate rain water removal. With this backdrop, the present work aims to capture the influence of camber angle (positive and negative) on tyre durability. In this work, two different pattern of truck bus radial tyre (one having rib pattern and another one having lug pattern geometry) were used for durability measurement purpose. Tyre tread surface temperatures were also measured during tyre in running condition using Infrared Red thermographic technique. Static tyre footprints were captured at various camber angle to understand the contact mechanics. Tyre durability results revealed that increase in camber angle decreases the tyre durability in terms of number of hours running till failure. In both the tyre sizes, failure occurred at the shoulder area due to application of camber angle.