Cavitation damage in tire rubber materials

The aim of this study is to investigate the internal damage of tire rubber materials due to cavitation. The formation and the growth of cavities (= defects, holes, voids) is induced by multiaxial stress situations, which occur, for instance, in rubber parts with inhomogeneous strain distribution, such as for deflected tire treads. Different experimental techniques are used to study the mechanical properties and failure behavior of rubber materials in terms of cavitation. The formation and the growth of cavities in so-called pancake specimens were explored experimentally by dilatometry and X-ray computed microtomography. Additionally, structural analysis of the crack tip zone of planar specimens has been performed using small-angle-X-ray scattering. Intriguingly, in all cases, cavitation damage has also been detected in "carbon black free" and "zinc oxide free" rubber systems, although the cavitation phenomenon is often attributed to interfacial failure between soft matrix and rigid particles.