95m3racer

Add Factory Ferrari to the "X List"

bruinbro

Probably can't afford anything else after what they spend on the rest of the car.

Bro

complexx

Hey Luis,

We haven't had the cage installed yet. It's going in sometime mid April (hopefully).

I will surely post pictures afterwards

-Frank

Geo

OK, here is the layout of my cage if you want some real dimensionsl. Tubing is 1.5 x 0.120".

If you don't mind, would you add tubes to either side of the X and below (with and without for comparison)? I'm guessing that will add more strength than gussets.

Geo

Here are some alternate side tubes (the reinforcement to the X and NASCAR bars).

95m3racer

This is the setup I am using to get design cues from, primarily the energy management components (with similar door xbrace just more gussets). EPP filling the door shell cavity, and an aluminum honeycomb panel composed of two 3/4" cores with laminate in between covered in carbon-kevlar (as it wont splinted). I was originally going to structurally-bond this in, but chose to bolt it in as in case of any damage it can be removed easily.

bruinbro

I'm a bit confused. Where is the main hoop 50" diagonal strut in the rear view? Also, what is the smaller rectangular structure? I'll generate a solids model with some of the tubes missing and you can fill me in (pun intended). Probably won't post it until tomorrow morning (PST).

Bro

bruinbro

Not sure how much energy management you are going to get out the door foam and that panel. Not enough depth of energy absorbing material to do anything worthwhile IMHO. The panel is cool, though, as it will do a nice job of preventing some high velocity debris from getting into the cockpit in a crash. Structurally mounting it won't buy you anything either from a structural perspective or a debris shield perspective, so good call.

Bro

Geo

The main hoop diagonal was eliminated in the drawing in an attempt to make things more clear. Didn't work.

The smaller rectanglular structure is the main hoop supports. There is a diagonal from the top of the passenger side to the bottom of the driver's side. Along the bottom is a horizonatal support.

I'd love to know the relative displacement of the X with and w/o the 3 tubes supporting the center of the X.


Thanks for the awesome work. This has been VERY educational.

bruinbro

I'm trying to construct a 3D model and I have to admit I'm lost. Do you have a sketch or picture of this cage? What would help is to know what are the redundant dimensions, if any. Also, is the door bar X in a plane that is perpendicular to the main hoop and is the main hoop in a plane that is parallel to the front hoop? I will be working on this tonight, so any help would be greatly appreciated.

Thanks,
Bro

Geo

Here is a web site with photos. I have more photos if you need them.

http://home.earthlink.net/~geo31/Geo's_944_Cage.html

Here is one example:

95m3racer

Actually, thats a BMW factory Motorsport component(s). Designed by the best

There is quite a bit of energy absorbption in that space, especially considering the overall distance between the outer edge of the dooe skin and where the drivers seat is.

It actually would do a LOT as far as structural rigidity goes. Thats the largest opening in the unibody, using a structural panel in that place with tear/shear panels bonding it in would significantly increase torsional rigidity (on that side of course, but with unobdoy shape it would even help the other side essentially as it would resist twist). The main (er, only) reason I don't want to bond it in is in case its damaged for one reason or another, it would be hell to get it out, so bolting it in just makes sense

The foam is the same material (different pcf) that is used in IRl/Cart/etc cockpit extrusions. The specific hybrid/composite foam I am using is a single impact, as the multi-impact EPP is just too expensive. This stuff is formed the same way you make Bead-seats. Beads+resin+vacuum=dense foam.

As you mentioned though it doubles as a nice anti-intrusion device, that really can't hurt the driver in any way. If the force is enough it'll disspate into the door brace. Usually there is not a force thats direct enough to have a pinpoint force (as a street pole on the street would cause). This is the only part of the car where there is nothing to absorb before the energy gets to the driver, so its pretty much the weskest spot.

bruinbro

Howdy all, I'm back.

Shall we start a new thread for George's cage or keep it in this one?

Here's the solids model as best as I can manage. Thoughts? The software says it weighs 127 lb; I'm going to check that.



Bro

95m3racer

Bro, I see some issues.

What is the radius uses on the rollhoop bends?

What are you using for material weight/composition? (assuming 1.5x.120 DOM mild steel?)

What are you assuming for Weld strength and weight?

Also, what are you using for constraints on the end of each mounting point?

Thanks.

Geo

Looks pretty accurate. The only thing not accurate is the littls space at the bottom of the 6 attachment points. It's no more than 1/4" (not sure if that will make any real difference in the analysis). Basically the height of the weld.

It weighs less than I would have guessed.

Steve, it's 1.5 x 0.120 as you guessed. That info was already provided. The real cage has all bend radii at 4.5" (minimum legal radius for that tubing).