Tire Stiffness Values Determination in Three Directions

[struclearner]

I need help regarding Tire stiffness values in vertical, longitudinal and lateral directions. The most available values of stiffness are in the vertical direction. There would be analytical formulae/equations to determine the stiffness values in longitudinal and lateral directions, could it be referred/mentioned from the professionals in the related field, please!
The objective is to model the full vehicle with tires and to represent the tires by springs for finite element static analysis, the vehicle model is subjected to vertical, longitudinal and lateral loadings.

Any reference to technical articles/books dealing the subject is appreciated.
Thanks a lot for help.

 

[GregLocock]

Lateral stiffness is of the same order as the vertical stiffness. One example I looked at was 400 N/mm whereas the radial rate was 300. I suppose it might be possible to pull it out of the Pacejka model (or whatever) of the tire. The effective contact patch location in front view is given by overturning moment /vertical force, so you could study how that varies with lateral force. It's the pneumatic scrub radius although I've never heard it called that.

Your other option is to take that long walk to the modal analysis lab and get them to measure it for you.

I suppose the same idea could be used in side view for the longitudinal stiffness, ie plot pneumatic trail vs longitudinal force. I have no feel for that at all.

Bear in mind that whatever number you get will vary with frequency, vertical load, tire pressure, speed and so on and so forth.

I've got the data and the tools, I'll have a go at pulling the 3 numbers out for you from real data, but I won't be able to tell you what the tire is or anything else about it.



Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[GregLocock]

That didn't work out, sorry. Equations are PT=(MY-FX*RR)/FZ and PS=(MX-FY*RR)/FZ, but this may be too crude a model of how tires work to get a reliable figure.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?