Rubber adhesion at high rolling speeds
1988
Roberts, A. D.
A rolling drum apparatus has been constructed to measure the surface adhesion of rubber up to high speeds. In this, a ball rolls freely on a continuous track of smooth-surfaced rubber. With speed increase, the rolling resistance rises to a maximum, then falls. The rise can be described in terms of a rate-dependent peel energy characteristic of the particular rubber compound under test. The fall at high speed appears due to a loss in grip either because of reduced contact duration or air film entrainment. Lost surface adhesion means that rolling resistance then becomes largely due to ploughing hysteresis in the bulk of the rubber. The relative importance of contact duration and air entrainment were assessed by study of such factors as rubber crosslink density, glass transition temperature and ambient temperature. Repeated rolling over the same portion of rubber track caused surface roughening. Experimental evidence suggests that the rolling action pulls fragments of rubber out of the track at a rate that can be estimated from the crack-growth characteristic of the track vulcanisate.
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