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Ppada
11-24-2005, 04:53 AM
Hello mechanics

I would like to ask to you about the bends of tubes in chassis. How they affect in torsional stiffness and impacts any bends made on Tubes but not the hoops? can anybody with analysis experience answer?
Ppada
11-24-2005, 04:53 AM
Hello mechanics

I would like to ask to you about the bends of tubes in chassis. How they affect in torsional stiffness and impacts any bends made on Tubes but not the hoops? can anybody with analysis experience answer?
Jersey Tom
11-27-2005, 03:58 PM
To be honest, beats me. But I see this thread hasn't gotten any love.

You could try mocking up a simple structure (ie not a full chassis, maybe just a third of one) in CAD and doing some FEA on it, see what happens.
magicweed
11-27-2005, 05:53 PM
I watched our frame guy do FEA for about 8 straight hours one day, and all I can say is that it helps. Another thing to do is look for open space with 4 sides in your frame design. Put a cross piece in there. We all know triangles are much stronger than squares and irregular trapezoids. It doesnt matter what size or thickness tubing it is, it will make your chassis stiffer. In some cases, it will be quite significant. Look at Texas A&M's chassis. They had the main structural members with what looked like 5/8" tubing as triangulation members. Same with Arlington (from the look of some pictures). Triangles are the way to go.
Fred
11-27-2005, 08:34 PM
Hey Ppada

Here are a few hints.

1 - Use the search feature of the forum, questions like yours have been previously asked (that explains the unpopularity of your thread !)

2 - The Cornell SAE paper on chassis design is really great. It will give you an excellent start point. (search it on http://www.sae.org using "FSAE,cornell,frame" for keywords)

3 - As said, it really helps to build an FEA model (Cornell's paper explains how to) but in my opinion, you should care more about fabrication than design at this stage (depending on your planning for this year of course).

Remember that the most important thing is to get your car running as soon as you can (or as soon as you can get rid of snow !).

Hope this helps.