Quote:
Originally Posted by Ernie Rogers
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Rubber Internal Friction and Stiffness
Some kinds of rubber are much more “efficient” than others. Remember super-balls? They were so surprising because they could bounce up almost as high as they fell. The ratio of <bounce up> to <fall> is the “coefficient of restitution” of the ball’s rubber. This is the efficiency with which the material returns strain energy as it rebounds. “Internal friction” is a common term for this kind of energy loss. The amount of energy lost by the tire rubber in each rotation is proportional to the amount of flexing, and that in turn is proportional to the weight of the car (for all four wheels combined). This is why rolling resistance is proportional to the car’s weight. These days, many tire companies put additives in the rubber to lower its internal friction.
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Can this be used for non-destruct measurement of relative tire rolling resistance?
Bob Wilson
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2019 Tesla Model 3 Std. Range Plus - 215 mi EV
2017 BMW i3-REx - 106 mi EV, 88 mi mid-grade
Retired engineer, Huntsville, AL
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