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Unread 11-12-2014, 20:40
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FRC #2851 (Crevolution)
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Join Date: Mar 2013
Rookie Year: 2008
Location: Utica, MI
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Re: pic: 2851 2014 off-season design: Bottom view with electronics

Quote:
Originally Posted by cfair View Post
It looks like you have a sheet metal frame. We do not have sheet metal sponsors, so we've never ventured into that scary place. My first concern for you would be parallelogramming (shear) for the chassis when you get a violent hit on the corner. The welded tubular frame does pretty well against those corner hits, but it still definitely needs a shear plate. Other teams would speak with more authority on how to achieve the same thing with sheet metal, but I would start with lots of rivets on your shear plate or gussets. I see you have basically created box cross sections for the sides and end members. That's great; you just need to figure out how to connect them and resist shear.

As for the advantages: the biggest advantage of tubular is simplicity. From my point of view, the easiest chassis is an off-the-shelf chassis, the next easiest is one the sorta off the shelf (like ours: we're using versablocks), the next is a custom one using plates or tubes (what we usually do), and the most difficult is sheet metal. Just so you know, we routinely find 1/8" wall 1" square tubing bending dramatically because of hits to our front and rear bumpers .
As shown here: http://www.chiefdelphi.com/media/photos/41002?
I do have a piece in the center on the bottom of the chassis to prevent shear, and the shooter bolted on top should help some. You don't think that would be enough? Also, the reason I did sheet metal was because I wanted to be able to do this with minimal hand fabrication at our build site. Another goal was for it to be easy to build, and as soon as we get the parts back from Accu-Rite, we can basically just assemble it.
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