Suspension Geometry Software

[Brian@indtech]

We have started a new program and are looking for suspension geometry software. We are trying to figure out what most schools use. Any help would be appreciated.

Indiana Tech Formula Team

[Denny Trimble]

Our Chief Engineer (now a Junior) started on the team his Freshman year, and his Sophomore year he wrote a VBA interface between Excel and SolidWorks for suspension design. All the inputs are specified in Excel, which controls a SolidWorks model of 3D sketches and planes, which then sends back outputs (RC heights, camber curves, bump steer, etc). It can also put the suspension through its expected envelope of pitch, roll, and steer (based on spring rates, anti features, and the measured course in Detroit), and plot any parameter as you transition from one steady-state attitude to another.

It took him all summer to create, and now it takes a while to digest a screen of 20 plots, but it's more flexible than any commercial package we've seen, and he learned a lot doing it.

We use another, simpler VBA tool I developed to design the spring/shock bellcrank linkages. Use Excel to increment the wheel vertically, and watch the shock & ARB displacement, plot it, generate incremental Installation Ratio, square it, find your rising or falling rate, change the CAD model, and do it all over again. Only one button to push to analyze a design.

[rtrey]

Brian,

We use Performance Trends Suspension Analyzer and Engine Analyzer. Both of these have a lot of problems. They tend to crash or totally revert to Demo mode. My advice is to stay away from Performance Trends in general.

[alfordda]

MSC ADAMS has big learning curve, but its free and really powerful.

[Mick_P]

At Swinburne we use Susprog3D and Solidworks in our dynamics design. Using solidworks to check clearances etc, and Susprog3D for the figures. We have however stumbled across a few short comings in Susprog3D, however it does serve a purpose as a cheaper alternative.
I would srongly recommend Adams if you have the time and energy to learn it properly - from what we saw at the Claude Rouelle seminar it is awesome http://fsae.com/groupee_common/emoticons/icon_wink.gif

[Storbeck]

That's interesting, at the FSAE Claude Roulle seminar this year he seemed to dislike adams, and recomended susprog. He also seemed to like mitchels. I've never played with either myself.

[RickyRacer]

I also remember Claude mentioning his dislike for Adams. He said that there are some parameters that could not be entered. He did like Susprog for its price and he also liked Mitchels. Is there anyone who has used Mitchels with success?

[Paul V.]

Hey Mick,
What are those shortcomings you've found on susprog. I would really like to know since we're just starting to use it.

Thanks,
Paul Vaughan
UAH FSAE

[Mick_P]

My bad, i am thinking of Mitchels. We had a guy from MSC call in though earlier in the year and give us a bit of a "walk- through" of the whole Adams package. From what i could see if you spent heaps of time learning every little trick, it would be awesome. But it does look a bit bulky to learn.
With Susprog3D we have just found a few issues with data outputs vs. what we end up seeing on the car - maybe our manufacturing technique though http://fsae.com/groupee_common/emoticons/icon_wink.gif

[fsae racer]

We have been using perf trends suspension analyzer for the past 3 years. It was about 3 years ago that I tried to learn the ADAMS software, but it ended up being a waste of my time, as our school was entirely opposed to helping us in any way. I will certainly agree that suspension analyzer has its short comings, but i feel it has a very user friendly interface and provides enough information to be worthwhile. It has a very unprofessional look in all aspects, as even the resulting graphs wont print entirely on normal 8.5x11, but at least for us, the info. and ability to calc multiple interations was priceless.

[steve d.]

denny,

I'm very interested in your SW/excel interface...

write me... steved033 at comcast dot net...

I'm not with a university...I'm finally getting around to my Dmod car...

sjd

[Denny Trimble]

Steve,
Good luck with the D-mod car!

I won't post our design tools, because we put so much time into them it's embarrassing. But, here's what got me started:

Monthly Macro - July 2002 (http://students.washington.edu/dennyt/fsae/Excel-VBA-SW.zip)

The code is stored in the Excel workbook. Edit that code and you can have multiple inputs / outputs, have the data go into columns instead of rows, etc. For a good VBA book, I've used John Walkenbach's "Excel 2000: Power Programming with VBA". There's a new edition out for Excel 2003 if you have it.

Here's to late nights in front of the computer...

[steve d.]

very interesting...

I know nothing about VBA...it doesn't look too complex...I'll ask my CS friends...

thanks.

sjd

[D J Yates]

Ok guys, could have done with this thread about a week ago. After spending the weekend writing a Matlab script file to perform geometry calculations i'm still short of a useable design. The script file works within a small envelope of dimensions specific to our car, and has produced some good results, camber gain is -0.2 degrees per inch, RC movement (lateral and vertical) is about 0.3mm per degree of roll; however the method is very limited and the geometery may well prove impractical and possibly unusable.

What i want is something that acurately models the physics - force roll centers not kinematic (anyone know what method susprog3d uses), so not Suspension Analyser (waste of time IMO) - but doesn't require me to specify every last detail of the bellcrank orientation etc, i'll go as far as specifying geometery and wheel ride and roll rates. I'm also not bothered about a visual output (although i won't refuse it) i just want numbers.

Did someone say ADAMS is free? How and where can i get it?

[alfordda]

Here is a link to the ADAMS sponsorship page.


http://www.mscsoftware.com/support/university/student_competitions/free_car.cfm

[Chris Boyden]

A good way to learn VBA is to have Excel record
macros as you work. Then you can take a look at the code as the machine generates it. At the very least, it gives you a way to get started. It can really pay off when you have a bunch of mundane tasks to do in Excel 40000 times....
alt-F11 launches the VBA software when you are working in Excel. The help files aren't too bad and there's a bunch of resources on the net.

[MotoDave]

A really good resource is the Microsoft Deverlopers Network, I found it pretty helpful over the summer when I had to teach myself VBA programming for a job.

http://msdn.microsoft.com/

[Ryan Colton]

We have been using Mitchell software for the 2004 car and now the 2005 car. The software is great for designing geometry but it is not dynamic modeling software and only does static loading and geometry. I recommend this software for initial geometry design.

We too tried to write are own code to help create our suspension geometry. The program that we wrote did work though it did not have the functionality of the Mitchell software.

[Paul V.]

DJ,

Susprog just runs atop mitchels FYI.

I have been STRUGGLING to write a MMM diagram into my MathCAD program but I have a problem. I need to iterate my worksheet, but I use solve blocks within it. problem is I cannot use the solve block within the structured program, and I cannot pass the values to it if I call it from outside the program. If ya'll use mathcad how can I fix this? If you don't how do you produce your MMM diagrams?


Paul
UAH FSAE

[D J Yates]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Paul V.:
DJ,

Susprog just runs atop mitchels FYI. <HR></BLOCKQUOTE>

I guess you were refering to me. I'll have to start signing my posts, it just sounds wrong being called DJ.

I don't really understand your comment. Probably doesn't matter though since the powers who be aren't prepared to pay the £100 required to unlock the program, or any other. We get nice team T-shirts though, so as i spend another week sat in front of my PC writing programs and trying to achieve satisfactory suspension geometery at least i'll have a nice T-shirt to do it in.

Can't help you with mathCAD. It's Matlab all the way for me.

[Daniel Sayao]

Does anyone can help me?

I'm looking for the Mitchell's Win Geo 3.0 Guide..

if anyone has this archive ein .docor .pdf, please sent to my mail..

daniel_sayao@hotmail.com

thanks!

[R. Alexander]

You can do wonders in Solidworks once you get to know the meanings of all the planes generated.

We used OptimumK with very good and easy results for the past 2 years and recommend it.

[D.J.]

I used lotus to design this years suspension. It was easy to use, basically just careful plotting of points. The graphs it outputs were awesome and they even gave us the copy for free.

We tried using solidworks first and it seemed a lot more complicated than necessary to get it to work dynamically.

[Pennyman]

Originally posted by Daniel Sayao:
Does anyone can help me?

I'm looking for the Mitchell's Win Geo 3.0 Guide..

if anyone has this archive ein .docor .pdf, please sent to my mail..

daniel_sayao@hotmail.com

thanks!

I've heard Mitchell is a pretty nice guy. Maybe ask him!

If you have his program already, it should be pretty easy to understand with or without the manual.

[G.Arce]

Good afternoon!
I need help with the Lotus Analysis v5.01, as I am trying to take some high quality pictures from the Static display and of the graphs.

However I can only find a 1233x633 resolution one with either .jpg, .png or .bmp

Any idea? Thx in advance