Better tyre performance

Elastomers are a class of polymer having elastic properties, of which rubber is a familiar example. Understanding elastomer characteristics is important to the design of tyres and new tyre materials.

The EU-funded TELLUR (Tribology of elastomers on lubricated surfaces) project examined road-tyre contact, plus the structure of both surfaces. Specifically, the group intended to document braking performance under wet conditions. The team also planned to produce worn asphalt to test tyres' friction properties on such surfaces. A further goal involved examining the characteristics of various rubber components, and their effect on final rubber products. Lastly, the group aimed to develop powerful software to analyse the infrared images produced during testing.

The first stage involved studying wet braking in terms of friction and road surface roughness. Work yielded a SWIFT model including an ABS controller model. Other results include publication of a full parameter set for a modern summer tyre. Project members also published the methodologies employed for obtaining SWIFT model parameters from study vehicles and for analysing road surface data.

A subsequent phase entailed enhancing friction tests with advanced imaging techniques. The work helped document why rubber begins sliding and what happens during sliding. Outcomes led to a new testing protocol, which increases precision and reduces costs. The team also achieved improvements in lab-road friction correlation.

Studying the wear of asphalt samples yielded a method for producing durable samples, suitable for use during laboratory friction tests. The method achieved a good match between manufactured samples and real road surfaces.

A final stage involved development of a software tool for processing and analysis of high-speed infrared images. Work resulted in a conversion tool allowing use of existing processing software for all image formats. The team produced a methodology for segmenting the images of a tyre surface.

The project also began collaboration with new and related Seventh Framework Programme (FP7) projects, including LORRY.

TELLUR has extended understanding of elastomers and tyre performance, potentially leading to improved designs and compounds. Additionally, the project's software is broadly applicable to other research fields, including biomedical imaging.