Hard Problems with Soft Materials: The Tribology of Elastomers

Tribology is the branch of science and technology concerned with interacting surfaces in relative motion, including friction, wear, and lubrication. Here, the study of friction and wear is discussed as it applies to elastomeric materials with an emphasis on combined rolling and sliding contacts. Under these conditions, materials can experience millions of cycles as well as complex loading and slip conditions, which can dramatically affect their friction and wear behavior. It is shown that for a carbon black-filled natural rubber compound in combined rolling and sliding contact with a smooth alumina coated disk, the traction coefficient, as a function of slip percent, is dependent upon the normal load and independent of rolling velocity. The wear rate of this material pair was found to be independent of slip percentage as well as rolling velocity but dependent upon the sliding distance. The wear rate was found to be approximately the same for all tested cases (K~1x10­­­­^-4 mm³/Nm).