Adhesion and Friction for Three Tire Tread Compounds

Abstract

We study the adhesion and friction for three tire tread rubber compounds. The adhesion study is for a smooth silica glass ball in contact with smooth sheets of the rubber in dry condition and in water. The friction studies are for rubber sliding on smooth glass, concrete, and asphalt road surfaces. We have performed the Leonardo da Vinci-type friction experiments and experiments using a linear friction tester. On the asphalt road, we also performed vehicle breaking distance measurements. The linear and non-linear viscoelastic properties of the rubber compounds were measured in shear and tension modes using two different Dynamic Mechanical Analysis (DMA) instruments. The surface topography of all surfaces was determined using stylus measurements and scanned-in silicon rubber replicas. The experimental data were analyzed using the Persson contact mechanics and rubber friction theory.

A Discussion on Present Theories of Rubber Friction, with Particular Reference to Different Possible Choices of Arbitrary Roughness Cutoff Parameters

“…Here, we shall use in particular a simplified version for the viscoelastic losses, since they are no longer considered so relevant. Persson, indeed, in recent papers (Tolpekina & Persson,[14], see also [15]), seems to agree with Klüppel [10][11][12] (just looking at the how the friction data are separated into viscoelastic and adhesive contributions) that the contribution due to adhesion is now considered prevalent over the hysteretic one. Obviously, this shift is also a sign of the uncertainty of the choice on how to interpret the two contributions (viscoelastic and adhesive ones), which appear to have a similar bell-shape.…”

“…In conclusion, the theories of rubber friction seem to have evolved over the years, but now the emphasis on the viscoelastic losses for tire-road contact due to fractal roughness has been much reduced, because the adhesive term is considered dominant. Persson's theories [4,[13][14][15] seem to have evolved more rigorously in the contact mechanics treatment (they are approximate, but the…”

“…To analyze typical compounds of interest in asphalt vs. tire contact and to give a quantitative example of the analysis made, all of the following is referred to the experimental data obtained by Tolpekina and Persson [14] (TP in the following) for three different reference compounds A, B, and C (see [14]), on which quite general information are provided: "B is a summer tread compound filled with carbon black. A is a summer tread compound filled with silica and containing a traction resin.…”

“…In their paper, TP [14] tested three different compounds: A is a summer tread containing silica and resin, B is a summer tread filled with carbon black and C is a winter tread filled with silica and traction resin. The viscoelastic moduli of the three different rubber compounds A, B, C, are detailed in Figure 2, as storage (Re E) and loss (Im E) moduli.…”

“…The available measured data for low velocities (LV) and higher velocity (HV) was obtained by TP [14] using two different experimental setups. Friction for LV was obtained by means the Leonardo da Vinci experiment, which allows only measurement of the friction coefficient on the branch of the µ(v)-curve where the friction coefficient increases with increasing sliding speed.…”