No abstract

The friction in tribo-systems that contain viscoelastic materials, such as elastomers, is relevant for a large number of applications. Examples include tyres, hoses, transmission and conveyor belts. To quantify the friction in these applications, one must first understand the contact behaviour of such viscoelastic materials, both in static and in dynamic situations. This work discusses an experimental study into the change of the contact area with the sliding velocity and relates the change in contact area with the mechanical properties of the elastomer. The results show that for a tribo-system containing an elastomer, there is a threshold velocity, above which the size of the contact area significantly reduces.

Elastomeric materials are widely used in daily applications, such as conveyor belts and wiper. Generally, elastomeric materials show poor tribological behavior. Adding fibers to an elastomer is a way to solve this problem. The orientation of the fibers influences the mechanical and tribological behavior of the elastomers. In the present study, the effect of shortcut aramid fiber orientation on the tribological behavior for a Styrene-Butadiene Rubber (SBR) was examined. Three types of compounds which have different fiber orientations were prepared, resulting in normal, transverse and longitudinal orientation to the sliding direction. A contact model of the viscoelastic-anisotropic behaving elastomer was used to calculate the contact area. The friction and wear of the compounds were evaluated using a pin-on-disc tribometer. The results show that the frictional shear stresses of all compounds are nearly the same due to the presence of fibers on the wear track. The normal orientation of fibers shows the most effective way to increase the wear resistance compared to the longitudinal and transverse orientation of the fibers.