FSAE Tire Test Consortium -- Round 3

[flavorPacket]

well, at least now we can all look and see how much Goodyear have biased their sidewalls to help with orientation

[rkellz007]

As I understand the assymetry it is not a sidewall construction issue, but instead something in how the contact patch is molded.

[RichE]

I'm not sure how the Stackpole Engineering Services model handles surface friction coefficient variations. We may want to ask SES about that.

Hi Edward,

The Stackpole Engineering model gives coefficents for a Pacejka 96 Magic Formula tyre model. In this model it is possible to use several user scaling coefficents to manipulate the data, one of which is a peak friction coefficent. Adjusting this value effects the tyre data in much the same way as you describe for the MRA model.

hope this helps people to use the data.

On another note, I wanted to try and evaluate the transient properties of the tyres, in particular the relaxation length. I am trying to model in more detail turn in and other transient events where the lateral force lags behind the slip angle.

I have noticed from one of the files on the dvd from calspan, "TIRF-SA_procedure" that the SA data is not actually the raw measured data and that it is passed through a program to remove the very hysteresis I was interested in measuring. Do you know if it is possible to get a copy of the raw data or has this now been deleted?

thank you
Richard
Cardiff University

[Edward M. Kasprzak]

Richard,

Thanks for the feedback on the SES model. As for the SA procedure, I looked back at the cover letter in the "fromCalspan" folder. It turns-out that the SA procedure is only applied to the raw data in the Mixed units folder (which SES uses).

The raw data in the Metric and USCS folders are untouched, so they have the (small amount of) hysteresis you're looking for. We swept slip angle at 4 deg/sec in the test to avoid a lot of hysteresis due to slip angle transients. The data is meant to be approximately steady-state. This is somewhat unfortunate for your purposes, but transient testing is yet another discipline we could investigate in a future test.

That said, there should be transients apparent in the warm-up and at the start of each slip angle sweep where the sweep rate is much higher. This data, however, is not provided by Calspan's data reporting routine (plot slip angle vs. elapsed time to see the gaps in the data). I'm working on the Round 3 data now, so I'll ask Calspan if they have the "full" data sets kicking around, or if they only collected data at the times we see in the files. If they have the "full" data I'll get it on the Round 3 DVD.

Edward

[RichE]

Hi Edward,

Thankyou for looking into this for me. I would be very interested to see the warm up and conditioning data if it is available.

Many thanks
Richard
Cardiff University

[flavorPacket]

I'd like to echo Rich's request. The way a tire is run-in on the flat trac made a huge difference in data during my team's force and moment testing

[Ulf]

Hi Edward,

any update with regard to the evaluation of the test data? Are the DVDs still likely to be sent out by next week?
Can't wait to have the new data...

Cheers, Ulf.

[Edward M. Kasprzak]

Yes, next week is still the target for shipping the DVDs.

Edward

[duckei]

I and other members of our team want to join the tire test consortium. It seems like a good investment as we are running Hoosier's and we don't have exact tire data. Have any of you been successful using this data? Is it worth the price?

Thanks

-Ian

[Hyder]

Hi everbody i am new to this forum, joined recently.
Can anyone help me, I need to know what are the forces which will develop in the machine frame and their formulas.

I am designing a static tyre testing machine which should capable of measuring lateral, longitudinal,vertical and cornoring stiffness, can any one help me to comeplete my project.

waiting for the response.