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Discussion Starter · #1 ·
I always thought cages were there to stop the bodywork collapsing. What do you do when the cage itself collapses? A HANS device is about as useful as a band aid on an amputation when something like Petter's accident happens. How his co-driver escaped serious injury is beyond me.
 

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> What do you do when the cage itself collapses?

Cross your fingers.

That cage took multiple large hits (like 6 or 7 they said), so after the first few it's ablitly to absorb the impacts was greatly diminished. Making the seat taller might be one possible bandaid, but then you need to consider that if it buckles, it might snap the occupant's neck.

You are right, though, Phil was very lucky on that one. Look at Pou's video from 2001, there is a shot of a car falling about 15-20ft onto it's roof, very similar to how Petter's car looked.
 

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>> What do you do when the cage itself collapses?

I've had it happen to me. Roof collapsed in much like Solberg's when we rolled only once but the roof hit a VW sized rock.
If you survive, build a better cage.
 

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>>> What do you do when the cage itself collapses?
>
>I've had it happen to me. Roof collapsed in much like
>Solberg's when we rolled only once but the roof hit a VW
>sized rock.
>If you survive, build a better cage.

However, when you hit hard enough to start bending the cage, proper cage design allows it to absorb the energy (by deforming) while protecting the crew. It doesn't take a big hit to bend or break the cage if the load is concentrated. I haven't seen pics of Petter's car, but I have seen other cars where the cage has collapsed/failed (including the one Dave was in). If you build the cage too strong then you start transferring the loads of the crash to other things (primarily the occupants).

Adrian
 

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RE: bad pics

You can build the strongest cage in the world, but then it's likely to just go right through the floor. So then we need a stronger floor.........or we should just avoid doing 150 into a concrete tank barrier. How Phil just climbed out of that car is mind-boggling, with every hit you could just watch the roof move closer in on his head.

Though I am considering adding a couple bars to the new cage design now...
 

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RE: bad pics

The cage in that car is made of T45 and the tubing is pretty thin. I never put a caliper on the tubes so I don't know exact dimensions, but I remember being very surprised by how thin and light each tube was before being welded in. The engineers designed it that way so that the cage would crush and absorb some of the energy from impacts instead of transfering it to the occupants inside. It might look bad, but the fact is, that car took 6-7 very large impacts and both inside lived to tell about it. Yes, the cage deformed a lot, but not enough to kill or injure the co-driver. I would say that the engineers did their job and probably saved two lives in the process. A much stiffer cage would have deformed less, but the higher g-loads could have caused all sorts of problems, spinal compresion, base skull injury, etc.

Alin
 

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RE: bad pics

The former Open class Subarus ran a datalogger on the floor behind the driver's seat. It's encased in aluminum but will not survive a direct hit. The WRC shells may have moved it to a more central and safer location but I don't know for sure.

Alin
 

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RE: bad pics

The cage in the WRC car is not made of T45 but rather 15CDV6 last I checked. Ulinke any of the rally cars seen here in the state the top of the roof bars is not tight to the shell but rather sits approximately 2" below the roof maybe a little less. I sat in the car Petter drove in Germany a week prior at the workshop and I was talking ot the engineers about the cage. They had made the cage to for a survival cell around the crew which was a little bit different then how they had done it previously.
 

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Discussion Starter · #11 ·
RE: bad pics

Having seen the car afterwards, my question is, would Phil have survived serious injury had the car had ONE more hard hit! Makes you wonder!
 

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RE: bad pics

Tifosi, has the roll cage material spec changed recently then because the SRT USA shells were running T45 in 2002. I didn't think to ask if the material changed with the WRC shells of 2003. Shoulda checked with Ed when I had a chance I guess.

Alin
 

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RE: bad pics

As far as I know hey are not using the T45 I can check and get back to you but I am almost positive that they are using the 15cdv6 which is also being used in the Mitsu and Pug WRC cars for sure.

For those unfamiliar with 15CDV6 here is the breakdown: (Composition min-max)
C= .12-.18
Mn= .80-1.10
Si= .20
S= .015
P= .025
Cr= 1.25-1.50
Mo= .80-1.00
V= .20-.30

Tensile strength: 980-1180 N/mm2 or (143'000-172'300 psi)
Proof Strength (0.2%): >= 780 N/mm2 or (113'00 psi)
Elongation: >= 10%

Welding instructions: No re or post heat treatment, Tig with 1.7734.2

Now if you compare this iwth T45 you will see why this is a far superior material and lighter as well. but expensive 80-90 euros a meter.

Or compared to 25CrMo4 (close to SAE 4130)

C= .22-.29
Mn= .60-.90
Si= .10-.40
S= .035
CR= .90-1.20
Mo= .15-.25
Ni= .30

tensile strength: >= 650 N/mm2 or (95'000 psi)
Proof Strength (.2%): >= 520 N/mm2 or (76'000 psi)
Elongation: >= 13%

Hoe this provides a little food for thought.
 
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