Main Hoop Bracing Triangulation

[Henrique]

Hello guys,

We're developing a new chassis, but I don't know if this design is according to the rule. Somebody can help me with this?

Item rule:

B3.12.6
From the lower end of the braces there must be a properly triangulated structure back to the lowest part of the Main Hoop and the node at which the upper side impact tube meets the Main Hoop.

http://img225.imageshack.us/img225/3094/structure1.jpg

http://img152.imageshack.us/img152/9007/structure2.jpg

http://img849.imageshack.us/img849/840/structure3.jpg



Best Regards,
Henrique.

[Mazur]

No, that bend in the roll hoop must be triangulated.

[Henrique]

We modified our design. We tried triangulate all nodes.

http://img204.imageshack.us/img204/2697/str1a.jpg
http://img99.imageshack.us/img99/7400/str2e.jpg

[Mazur]

I'm assuming you're going off of the regular "structural equivalency" rules?

[Henrique]

Not exactly I think...

In my mind the attachment of Main Hoop Brace to Main Roll Hoop, just need to be a structure triangulated, not exactly one tube direct.

But, I don't know if this is correct.

For example img 5:

http://img580.imageshack.us/img580/6317/26791198.jpg

[Dash]

I just read through the rules myself. I think the following shows that it is not necessary, although it wouldn't hurt to add it. The chassis does meet the roll hoop bracing triangulation rule as well.

B3.4.5 If a bent tube is used anywhere in the primary structure, other than the front and main roll hoops, an
additional tube must be attached to support it. The attachment point must be the position along the
tube where it deviates farthest from a straight line connecting both ends. The support tube must have
the same diameter and thickness as the bent tube. The support tube must terminate at a node of the
chassis.

[AxelRipper]

Yeah, I'm thinking your original design would work. I'd email the rules committee to be sure, but I believe that everything you need to have triangulated, you have triangulated everything that needs triangulating. The biggest question I guess is the interpretation of rule B3.4.5 like Dash posted, namely the other than the front and main roll hoops line.

[Owen Thomas]

If that's your shoulder bar (for driver restraints), then the bend must be triangulated. The bar providing the triangulation must also be .095 too. They turned down our initial SES for this exact reason this year, however we have not had problems with it in the past (odd, I know). This was for FSAE Lincoln. Like everyone else said, I'd send your question to the appropriate rules commitee just to be sure.

[Mazur]

I specific reason I asked about what chassis rules your team is following is because it seems violate the "direct impedance" rule, which must be followed under the alternative frame rules.

The area right in front of the front roll hoop is the area that sticks out to me.

[moo moo racing]

Guys, i have searched the forums for a definite answer regarding pipe thicknesses for the figure 5 shown above..It is a structure that is properly triangulated from bracing to main hoop, but there is no 'definite' main hoop bracing support for which 1.2mm thickness is mentioned in rulebook..Should 1.2 mm be used throughout the rear structure in this case also?

[moo moo racing]

The post i was referring to was 'Henrique's' with the picture with caption 'main roll hoop brace bar support options'