Just a note, Denny is from University of Washington, WWU (Western Washington University) is an hour north of us and a different school with their own car.

Denny, im dissapointed, the chain looks like a belt! just for interest sake, has anyone managed to make a chain in their solid models?

top job, i hope you think imatation is the best form of flattery, cause im going to start using layering in photoshop to do our images now too!

- absolutely everything was available to him, but that only meant it was impossible to find what he was looking for, which is the purpose of computers.

I spent a day on this last Christmas break. It works, but it's way too slow and resource-intensive. Maybe for next year's design report



University of Washington Formula SAE ('98, '99, '03, '04)

Denny,

Why have you moved away from the tube uprights? I really liked this idea last year and tried to get my team to switch because I thought the jigging and manufacture time would be really short with a tube upright. We have continued using sheet metal monocoque uprights, like you have switched to though. I know that the loading on the sheet metal ones is better, but wondering if there is any other reason behind the switch?

Brent

www.ucalgary.ca/fsae

Basically, our focus for that part shifted from ease of manufacture last year, to stiffness vs. weight this year. The boxed steel uprights take about twice as long to make, but they're not that difficult. That's just the way the compromise went this year.

University of Washington Formula SAE ('98, '99, '03, '04)

quote:

---

Originally posted by Frank:
and some new stuff (2004)
the suspension CAD is my "dumb suspension", that moves around via a spreadsheet

---

Good to see someone else whos done a spreadsheet, I thought i was the only one to do a kinematics package in Excel!

How close are your results to other packages? I'm quite pleased with mine, surprisingly accurate

I make a “3D” sketch of the node points.

This drives a spreadsheet.

From the spreadsheet, you get the data for Suspension Analyser 3D, for static setup.

A weight transfer spreadsheet then gives me values for SusA for lateral acceleration accounting for tyre deformation.

The spreadsheet drives a whole assembly of “dumb suspension” , from which you can check interference etc.

Spreadsheet values are used for maple worksheet to find wishbone forces, and node reactions.

The shocks and sway bars are “drag and drop” in the Assembly (keeps the “in plane” constraint).

A few hyper-linked CAD files solve the motion / installation ratio.

***Images Removed***

The idea is to be able to derive a suspension design both mathematically correct and visualised in short time.

I can do this now.

For instance, the hardware (sphericals, rod ends, etc) staying the same, I can derive and visualise a complete geometry in under 30 mins.

If I have to change to pullrod, it's a little longer, because the CAD needs a slight modification, but at worst 2 hrs.

This provides a very flexible environment for chassis design. In a few days we can thrash out a great many designs.

About the only thing that I haven't got is a steering rack that changes, I'm kinda stuck wth it's width in the 3D graphics.. but I like it's width anyhow.

The only thing that can be a little inacurate is the roll calculations in the spreadsheet, because I'm approximating a MDOF system. Provided the non-suspended weight transfer and the geometric weight transfer is small (compared to the elastic weight transfer) ((which is hopefully the case IMO)) the results are ok.

oooohh I feel "exposed" all of a sudden.

[This message was edited by Frank on March 04, 2004 at 09:51 AM.]

[This message was edited by Frank on March 04, 2004 at 01:13 PM.]

[This message was edited by Frank on March 04, 2004 at 04:55 PM.]

Awesome! You've taken it one step past what we've done. Last year I made up a solidworks/excel macro to drive our pullrod/bellcrank assembly and record the travel and plot IR vs. wheel travel. Then, this summer one of our very ambitious Sophomores wrote a huge spreadsheet where you specify the suspension properties (RC's, VSAL, track, etc.), and it calculates the points required, putting them in a 3D sketch. Then, if you enter spring and mass and acceleration and steering inputs, it runs the car through "virtual corners". Pretty cool for a 2nd-year summer project for no credit.

I guess we'll have to extend it to 3D now to keep up with the aussies

Good job Frank!

University of Washington Formula SAE ('98, '99, '03, '04)

thx Denny,

now i gotta get the other guys to actually draw their parts in detail so we can mass model better and present good design images.

it'd be great to visualise the car going through corners.... that sounds great too

here's something you might find interesting...

http://www.temporal.com.au/motec.htm

dunno if it will make a release.. it would be nice to see though

Nice work to everyone. I just thought I'd share pics of our car model up here in Wisconsin. As always, love to hear comments or questions.

http://www.gotocfr.com/fsae/

For the start-up teams...

These type of design tools; using hyperlinks between CAD parts, simple assemblies, and complex assemblies; realises the power of CAD.

The co-operation and ease of iteration between the chassis and suspension geometry is IMO the most difficult and time-consuming task in the initial design process.

If you get it "happening" the design of these cars is so much quicker.

Recently I had the misfortune of trying to use the AutoDesk Inventor software.. (in a "Professional" race team's "design centre")

It was absolutely f***ing useless. A complete joke. There was NO WAY you could do this sort of flexible design using that package.

Get yourself a CAD package that can reliably and easily link between models and external tabular data.

I have used Solid Edge and Solid Works for these type of design assemblies. Both are quite capable of these tasks.

Frank

sweet Tim,

how close is that muffler to the ground?

Frank:

Thanks...and its 1.75" off the ground

Tim Isenberg

might that cause heartache in the "noise test"?

just a guess...

but then again i've seen a team (can't remember who) use a tip that "points" directly at the ground

Denny,
Those are remarkable. Your pictures in last years design report impressed me but these ones are considerably better. It’s a shame that they won’t get us a win in Design.

We went with the draft style layout pictures, kind of boring pictures but I’m proud of the car. On our optional page we decided to include mostly pictures of the stuff we made. It was damn hard to limit it to one page worth. I think that I have about 4500 pictures of this car (no exaggeration) and I had a tough time choosing which ones to include.

What have other teams been including on the optional page?

http://dot.etec.wwu.edu/fsae/Design_Review_Pics/
First link is in MS Word and has full resolution pictures. The second one is .pdf

Tim, I am a big fan of the UW-Madison car. Nice work. Any other teams willing to share picures?

James Waltman
http://dot.etec.wwu.edu/fsae/
Vehicle Research Institute at
Western Washington University

Continuing the off topic theme....Interesting to see other peoiples approaches, and how even though people are on different continents, the results are nearly all the same.... Frank, that spreadhseet is almost the same as mine, and a suspect a lot of others, with the exception of the linking to the CAD system, something I think worthwhile investigating.

James, your Sophomores spreadsheet sounds similar to this:

ssv10_1

ssv10_2

ssv10_3

except mines only in 2D, it also includes a very basic kinematic analysis, useful as the parameters are quickly changeable so you can get a starting point very quickly.

This then gets exported via another(!) spreadsheet into ADAMS values, and even though ADAMS calculates roll centres differently, its not too far off. Next on the agenda is to incorporate tyre stiffness into it.

What does everyone do regarding handling? I have created a few more basic spreadhseets for 2D bicycle models, only linear tyres at the minute, and havnt had a chance to quantify how accurate, have tried pair analysis, but havnt got much out of it

edit: hmm, geocities doesnt like remote linking, try

http://uk.geocities.com/stuartchamberlin/fsae_pictures/

Here are a couple of random renderings of UIUC's car. These aren't what was used in the design report though.




Eric Wort
UIUC Formula SAE

Hey Denny,

Great job on the drawing submissions! They look great! I can't wait to see that car at competition this year. If the pictures are any sample of what the design report is like, I think we should all be watching out for Washington.

Denny, what is the status of your car?? Running yet?

- Erick

FSAE ('99 '00 '01 '02 '03 '04 '??)

Erick,
Thanks for the kind words. How's your car looking this year?

Our frame sections are being bonded & bolted together tonight, with 80% of the parts ready to bolt on as soon as that's done. We're about a month later than last year's car, but it's a revolutionary change in design and manufacturing for us, so that's to be expected. The next two weeks, we'll be "in labor" delivering this baby I can't wait to see it!

University of Washington Formula SAE ('98, '99, '03, '04)

Denny,
Check your PM
PDR

I'd rather have a bottle in front of me than a frontal lobotomy