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.
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)
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Frank:
and some new stuff (2004)
the suspension CAD is my "dumb suspension", that moves around via a spreadsheet
<HR></BLOCKQUOTE>
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/