Must a tire slip to generate force?

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Shredcheddar
Shredcheddar
0
Joined: 22 Jan 2009, 06:16

Re: Must a tire slip to generate force?

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www.physics.hku.hk/~nanohk06/talks/Persson.pdf

Here is a quick slide presentation where Persson talks about adhesion and contact mechanics. Interesting and kept light due to the sub-par presentation method, but there are some good graphs in the presentation and I think it's a neat read as it just kind of overviews and introduces his theory.

riff_raff
riff_raff
132
Joined: 24 Dec 2004, 10:18

Re: Must a tire slip to generate force?

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Ciro,

I read the article you linked, "Why tires slide". The gist of that article was that tires grip due to surface roughness between the tread and road surface. That principle is similar to any other type of sliding contact. The tiny surface irregularities, technically referred to as asperities, are literally bonded together at the microscopic level for an instant due to the high local contact stress, and then immediately sheared apart by the relative motion of the two surfaces. That strain energy loss is what creates rolling resistance. Of course, most losses in a rolling tire are due to hysteresis losses in the tire body, and not the tread/track contact.

You are correct in your statement that two infinitely rigid bodies in rolling contact would have no friction losses. The reason is that infinitely rigid bodies are not, by definition, capable of experiencing strain effects.

Nice discussion about the subject. I enjoyed it.
"Q: How do you make a small fortune in racing?
A: Start with a large one!"

Shredcheddar
Shredcheddar
0
Joined: 22 Jan 2009, 06:16

Re: Must a tire slip to generate force?

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I agree with Riff Raff. Great contributions from everybody; I feel like my question was sufficiently answered, and that I've sufficiently justified that answer through your explanations and my own expanding understanding of the subject.

So thank you all. =D>

I've got another fundamental tyre-related question... but it's a bit off-topic (or OOT as Ciro puts it), so if you're interested, follow me over to another thread!