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

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

This message has been edited. Last edited by: rkellz007,

quote:

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

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

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

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

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.

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

Edward

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

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.

Hi everyone
please help

I am doing a project work in " designing a static tyre testing machine" which can test for lateral, longitudinal, vertical and cornering stiffness.

can anybody reply me what are the forces developed in the machine frame (shear force, bending moment etc and their example calculations if possible)

or can anyone suggest me a link or a report which contains material selection and its evidence and general force calculation.

In order to get masters I need to complete my project, please please please can anyone reply me.

I will be very grateful if I get a reply.

waiting for the response

thanks in advance

This may not be the best thread to ask this question. Those of us who are members of the Tire Test Consortium paid for this data that we could not get ourselves. I would think Cal-Span would consider this propietary information.

But to help you out, if you can figure out the loading at the contact patch, some Free Body Diagrams will tell you the loads into the frame you design.
I would hope that you want this information to be sure your rig is stiff enough to not affect your data. If you have any flexure it will throw off your data considerably. The rig should be significantly "overbuilt" for stiffness.

You could also try sae.org, there is a paper about the Tire Testing at Cal-Span. That may or may not help you at all. Also search the forums, it is the fastest way to find what has been discussed before.

Has the data gone out yet?

The data has not been shipped yet. We're waiting on SES and MRA to finish the models of the data. I communicated with Mike Stackpole at SES and he says he should have it done later today or early Monday. Same goes for MRA. Both are in the same boat--paid work caught fire and took priority.

I know everyone's eager for the data. We're doing the best we can. Once the models come in all I need to do is make copies of the DVD (appx. 1 day) and then ship them. The shipping materials are already assembled.

I'll post when the data is shipped.

Thanks for asking,
Edward

Still waiting on SES....

Any news on the projected ship date?

Hello Edward,

is it possible to download the new data from a ftp server?
Otherwise it will take quite a while until the dvds reach us and I'd like to shorten taht time as much as possible.

We're still waiting on SES. Everything else is ready to go--shipping labels and DVD labels are printed, customs forms are filled-out (for the international shipments), etc. Once I get the models from SES I will make the master DVD, get it copied (appx. 1 day), assemble the packages (1 day) and ship it. Considering it's already Wednesday the earliest it would ship is the weekend.

I appreciate everyone's patience. I know mine is frayed. I'm doing what I can to move SES along. I know it can be difficult since they're doing this volunteer work on top of their paid obligations, but at the same time it's been about a month now and I really hate to see all the students left hanging.

And to answer the other question, we won't post data on an FTP server. It's not secure enough and too much of a hassle to make it so.

Edward

SES came through, so I'm finishing the DVD, will have copies made and will have them shipped by the end of the week. I'll post when they've been shipped.

Good news. The Round 3 DVDs have been shipped. Look for them at your school sometime in the next week.