Got mine, thanks!

Does anyone know which rim width the hoosier 20.5x7.0 -13 was tested on in round two? Im trying to compare the two rounds of testing.

Now as far as procedure goes, was the belt "stoned" in all runs or just certain ones?

This message has been edited. Last edited by: FryGuy,

We just received our copy.

Thanks

Cedarville just got our copy too - and we're first-time members. Thanks so much for organizing this, and for putting all the work into those Matlab files!

The same belt was used for all Round 3 tests. It was stoned before testing started, so it's the same surface for all the tests.

The Round 1 and 2 tests on the 13" tires used a 7" wide rim. Note that those rims were not used in the Round 3 tests. The Round 3 rims are steel and were purchased by the FSAE TTC so that all rim widths would have the same rim construction. The Round 1 and 2 rims were aluminum and were lended to the consortium for the project.

If you don't see your copy of the Round 3 data by sometime next week then drop me a note and we'll check your team's mailing address. The vast majority of you will be okay, but with appx. 130 DVDs shipped it's not unreasonable to think that at least one will have an issue.

got ours this week, thanks Ed

Hi all, I'm really interested in buying this tyre data for our team... We're developing a vehicle dynamics model. But has the new testing surface brought the peaks to more sensible levels?

Also am I right in understanding that the non-dimensional model can be used to 'correct' the data from tests 1 & 2 for more realistic lower peak friction values?

Many Thanks,

Jon

Jon,

First, the stoned surface made little difference in the peaks. Second, yes, the nondimensional model allows the surface friction to be adjusted, affecting the shapes of the curves in reasonable ways.

Dr. Edward M. Kasprzak I sent you an email last week about not receiving our CD yet. Did you ever get it? I never recieved an email back.

Scott Mingay
smingay@rutgers.edu

Hi,

Does anyone got this error using the ExpansionType 5 with any of round 3 tire data file:

quote:

??? Error using ==> rdivide
Matrix dimensions must agree.

Error in ==> U:\TTC_Data\Round3\fromMillikenResearchAssociates\expand_mrandim.p>expand_mrandim at 792


Error in ==> call_mrandim at 209
MZ = expand_mrandim([5,units],NDIM5,[FZ,SA,IA,0,mu]); % Call to MRA Nondimensional Tire Model

We tried hardly to find the problem but since it occur in the .p file we can't get acces to the code to find which matrix are involved in the rdivide operation.

So please if someone got this error and find the way to get thru or if Dr. Kasprzak could take a look the code and help us to resolve the problem, we would appreciate very much.

Thanks!

Scott,

Yes, I replied to you, but the mailer-daemon couldn't deliver it to your address.

Milliken Research has been contacted regarding problems with the aligning toruqe expansion. We've scheduled it among our current work and hope to have a resolution next week.

Hi,

I just started using the tire data from FSAE TTC. I am building a vehicule dynamics model but I am not sure in wich direction is the FY returned by the MRA Nondimensionnal model. Is it always perpendicular to the belt displacement or is it in another direction (perpendicular to the tire) ?

Does anyone can

simon_o

The MRA models follows the SAE tire axis system. That means that lateral force is perpendicular to the wheel heading direction and positive to the right. It doesn't matter what the slip angle is or how the tire is distorting. The only thing that matters is the wheel.

Ok thank you!

Is it me or the "camber effect" on lateral and longitudinal loads is reversed for the Goodyear tires?

We plotted a graph showing FY vs SA for a given FZ and various camber. According to SAE tire axis system, negative IA should produce a negative FY @ SA=0 but on the graph we find a positive FY @ SA=0. Also, we can see the tire generate FY load for IA=0 while other tires generate nothing @ IA=0.

On a second graph showing FX vs SA for a given FZ and various camber. The graph shows that the higher the SA, the higher FX is. This don't really have sense.

Am I right? Could someone tell me how to correct this problem. I looked at other tires (round 1, 2 and 3) and "camber effect" seems to be right for those tires.

Have the runs 53, 54 and 55 (with the tire in the backward direction) been included in the tire modeling process? Should we take into account the comment in the DVD content file (reverse sign for SA, IA, FY, ...) when using the MRA model or have this been done already when generating tire model?

Thanks!

This message has been edited. Last edited by: GooDLuC,

I don't think you are allowed to post those on the internet as of tire consortium contract.

FryGuy, you're right... I forgot about that. I removed the graph. I hope my post will be clear enough without graphs.

I would re-check all your graphs, they didnt exactly look right to me. That tire at certain loads does have some interesting camber effects but it still seems like your graphs didn't quite look right. They could be right but i didn't get a real good look at them before you removed them.

Hi, I investigated a little further and now I think FX curves for the Goodyear tires have sense.

However, I still can't explain the FY curves behavior.

For exemple: with a 250 lbs vertical load, SA=0 , IA from 0 to 3˚) I got:

*0 FY force for IA=0 (which have sense)
*an increasing neg. FY force as IA from 0 to 1 (which is in opposition of what would "normally" happen with other tires)
*an increasing FY force in the pos(+) direction for IA from 1 to +... (which correspond to the expected behavior of a tire).
*For negative IA, the same happen but with sign reversed for FY.

I also plot the same graph with the raw data of run 4 and 54 and what I see is FY going positive as IA increase (expected behavior).

I saw a lot of hysteresis on raw data graph i.e. for IA=4˚ tests pass trough SA=0 four times and 2 curves indicates a lot of FY+ and the 2 others indicate approximately 0.

I don't know where the error come from but I would appreciate if M. Kasprzak or M. Milliken could take a quick look at the Goodyear tires models vs Raw data and told me why I get these results and may be help me to correct the problem if possible.

Thanks!