Force Distribution for Tire and Rim Interface

[jek147]

I am attempting to simulate a loaded wheel (rim only) in a FEA package. I would like to simulate the radial test as specified by SAEJ1992 or SAEJ267. However, I do not know how to best simulate the forces/loads the tire exerts on the rim (TRA-J profile). Does anyone have any information or know of any published documents on the effects/forces the tire has on the rim during vehicle use (loaded)?

 

[CoryPad]

The SAE Technical Paper series is the best source. Go to the SAE internet site:

http://www.sae.org

Search for the following:

982840
1999-01-0781
2001-01-0745
2002-01-1202
2004-01-1578

These deal with wheel forces, etc., although you may not find the EXACT information for which you are looking.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[GregLocock]

Why not build an FEA model of the tire as well?

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[ChrisTabor]

The reason you may not want to build a tire model is the solve time and material properties/material composition. I run a unix machine with 4 processors and 8 GB of ram and to solve contact/wheel model/tire model it takes well over 4 hours to solve and for most of us that is not feasible. Also, the tire model is very difficult/impossible to create and have accurate contact with the rim.

The tire/rim bead interface if a difficult interaction that is more difficult to model than at first glance. Dr. Stearns from Goodyear tire company, graduate from University of Akron, Ohio, did his doctoral thesis and derived the contact analysis from an eyebar loading method. Still the vertical and horizontal components of both the inboard and outboard bead seat are still difficult to define.

Good Luck

Tabor

 

[GregLocock]

But once you've done it properly, once, you could build an empirical model of the tire/wheel interface, and use that for most of your runs.

I rather suspect that that is what other people have done, and they probably see little benefit in giving that information away.





Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[tireman9]

GregLocock and others
The problem with solving the problem "once" is that tires are not all alike and do not transfer the loads to the rim in the same manner.
Somce of the tire variables other than tire size or tractive force capability or stiffness or other general performance characteristice are in the bead area itself.

Even for one size tire the bead area involves specific variables such as wire winding configuration and diameter. Bead area rubber hardness and thickness. Multiple possible cure ring contours and slope and even the curing ring material can have an impact if the dimensions you are dealing with are at room temp not cure temp.
The numerous variations of each of these design possibilities makes slecting one combination, might work once but if you are at the FE level of analysis I would think you are after a more accurate model.

35 yrs Tire Eng. Designed basic rain Firestone for CART. SCCA & IMSA Pro & Am. Set lap records at 6 different road courses in '89-91.