Spreadsheet for Share

[Frank]

http://rapidshare.com/files/45090760/suspension.xls.html

excuse the spelling mistakes

[Frank]

http://rapidshare.com/files/45090760/suspension.xls.html

excuse the spelling mistakes

[Frank]

bump

[oz_olly]

Hi Frank,

The spreasheet looks like you have put a lot of work into it. Would you mind putting a bit of a blurb to go with it.

Cheers

Olly

[J. Vinella]

I second that.

Very generous of you to post this.

[pengulns2001]

wow, this is pretty impressive. you wrote all of this?

[Frank]

The suspension spreadsheet is something I've written sporadically over the last 4 years. I was motivated to write it after a Claude Roulle seminar, and I've always been keen to share it with others.

I'd really appreciate that if you use it, and you suspect an error, please tell me of the error.

This means a more powerful tool for people to share, in the long run.

It was used for fsae designs initially (UQ 2003-2005), and then on some "real race cars"� more recently.

I've had a few people check through the calculations over the years (it's hard to find someone to do this for you), and have done some physical testing that has given me more confidence that the calculations are correct.

If you're keen, you can build a "bare bones"� FEA model and replicate the output.

Blue cells mean input and red cells are important output.

I'm not 100% sure about the aero calcs, it would be great is an aero guy could confirm these.

This version allows you to input springs, motion ratios, and damping ratios. It calculates natural frequencies and damper rates.

Another powerful way to use the spreadsheet is to reverse the formula so that you input natural frequencies, motion ratios, and damping ratios. It then calculates spring rates and damper rates. This is particularly useful if you are designing motion ratios to suit difficult dampers (risse, fox etc, when used on fsae cars).

The spreadsheet uses a tyre spring rate. The formula for weight transfers are more complicated with a tyre spring rate. A lot of similar spreadsheets / calculators use the more basic "rigid tyre assumption"�.

I've left ARB rates as "torsional spring rates"� deliberately (ie the moment applied to induce roll of SM WRT NSM). The additional sheets assume a "double blade"� ARB, and allow you to chose between "active-active"� blades, or "active-passive"� blades.

The spring worksheet is a bit rough, it was written using basic formula from a design text. It has been quite a good approximation for the small fsae springs, but has been a little inaccurate for bigger springs. Regardless, it gives you an idea wether a certain motion ratio will yield a feasible spring design.

The "wedge"� calculations only apply when a tail shaft connects the SM and NSM.

"Body Roll rel "Axle" (deg)"� is what you typically read in data streams.

Please note that both steering angles are positive if Cf is positive.

The main assumption is that all calculations are linear approximations (it does not consider movement of the mechanism).

Another major assumption is that Cf is always equal at all tyres, except acceleration, where rear wheel drive is assumed.

[designer]

How do I down load this file? I have tried several times and each time it has given me an error.

Could you e-mail it to me?

[Christopher Catto]

in the first web page scroll down and click on "free"

on the second web page, leave the selected option as it is (be it TeliaSonera or GlobalCrossing, whatever)

where it says "here", type the letters shown in the picture. this works like when you register a new email account. agains automatic fraud/spam softwares.

enjoy

Spreadsheet is awesome Frank. Nice job mate.

[blister]

Hey, this Spreadsheet is excellent. I have one specific question: What does "SM Rad. Gyr. Roll (m)" mean? and how to determine its magnitude?

I guess its something with Sprung Mass Gyration. But i`m not familiar with all englisch technical terms...

Regards!

[CU - Andrew]

Thanks so much for sharing!

[Frank]

sprung mass radius of gyration, about the rolling axis (K-roll)