Alfa Romeo C42

[jagunx51]

should the roll hoop be made from the same material as the Halo ?

[bosyber]

should the roll hoop be made from the same material as the Halo ?

https://res.cloudinary.com/engineering- ... pbrvyq.jpg

And mandated shape then, ie. spec part like the halo, and side-impact structures (though those are from carbon indeed)? Well, probably the FIA might consider it.

[Formula Wrong]

And mandated shape then, ie. spec part like the halo, and side-impact structures (though those are from carbon indeed)? Well, probably the FIA might consider it.

Surely they're gonna have a close look at why - and how - the structure failed. If the blade design is at fault they'll certainly at least mandate that it's an actual hoop structure.

[Big Tea]

should the roll hoop be made from the same material as the Halo ?

https://res.cloudinary.com/engineering- ... pbrvyq.jpg

The logical conclusion would join up both constructions with an integrated 'overhead' loop to the existing structure, angled back into the position of the current hoop. A survival cell sort of cage.

If inclined to the rear of the car it should not interfere with egress of the driver, but probably passing through an essential part of the designed airflow.

[michl420]

The blade design is not the fault, it is that is was not strong enough. But I also think a classic design gives more reserve in horizontal load.

[void]

It's not the first time Sauber's roll hoop failed, Pedro Diniz crash in 99

[Hoffman900]

Roll hoop failures are unacceptable in 2022. Indy Cars routinely go inverted and have direct roll hoop impacts and long slides with no failures for decades now.

Everyone is applauding the halo, and rightfully, but this is a major embarrassment for the FIA as well as the constructor.

[continuum16]

While it is 100% concerning that the roll hoop failed, the team passed the FIA crash tests, so I would imagine that the crash test requirements will be increased before any kind of shape is mandated. This will probably add more weight, and at the highest point on the car this is less than ideal in terms of vehicle dynamics. However, I doubt anyone would reject strengthening the roll hoop requirements based on what we've seen.

I know that Vasseur has already stated that the team would want to carry over things like the tub/survival cell to 2023, so if the requirements for the survival cell change, this could unfortunately have a major budget cap impact as well.

edit: I don't think the shape helps, it's common knowledge that triangular shapes disperse forces better than pretty much any other, and most teams employ a triangular or trapezoidal structure in this area. I think we have seen the last blade-style hoop, whether the FIA mandates the shape or not.

[Hoffman900]

While it is 100% concerning that the roll hoop failed, the team passed the FIA crash tests, so I would imagine that the crash test requirements will be increased before any kind of shape is mandated. This will probably add more weight, and at the highest point on the car this is less than ideal in terms of vehicle dynamics. However, I doubt anyone would reject strengthening the roll hoop requirements based on what we've seen.

I know that Vasseur has already stated that the team would want to carry over things like the tub/survival cell to 2023, so if the requirements for the survival cell change, this could unfortunately have a major budget cap impact as well.

edit: I don't think the shape helps, it's common knowledge that triangular shapes disperse impacts better than any other, and most teams employ a triangular or trapezoidal structure in this area. I think we have seen the last blade-style hoop, whether the FIA mandates the shape or not.

Right, so it's the FIA specs that are wrong. If they add weight, they add weight, but it is unacceptable. The FIA, I believe doesn't spec blow over testing either, which is a huge issue when a ground effects car goes backwards at speed. Not the case here, but these crashes result in cars coming down out of the air on their roll hoops at times, and if the roll hoop failed here, no doubt it would fail in that situation as well.

[continuum16]

...

Right, so it's the FIA specs that are wrong. If they add weight, they add weight, but it is unacceptable. The FIA, I believe doesn't spec blow over testing either, which is a huge issue when a ground effects car goes backwards at speed. Not the case here, but these crashes result in cars coming down out of the air on their roll hoops at times, and if the roll hoop failed here, no doubt it would fail in that situation as well.

Yes, I would imagine that the hoop would probably fail in that situation as well. It's a situation like most safety measures; it seems adequate until some crazy incident occurs, and then it becomes apparent that it's not...

The FIA crash tests probably could be beefed up anyways, like you said there are situations which they still don't test that they probably should. They unironically should consult Indycar, who have cars of a similar mass and also have had rollover crashes at high speed, including landing on the roll hoop and sliding a significant distance on the structure. At least find out what their tests and specs are, because that chassis has been in use for a decade and has had more than enough incidents to gather data from.

[Just_a_fan]

The blade design is not the fault, it is that is was not strong enough. But I also think a classic design gives more reserve in horizontal load.

Looks like the roll over blade is a solid lump bonded to a solid lump bonded to the top of the tub. You can see what appears to be the remains of a bonding agent on the stump here. Seems like a poor piece of design that meets a test but has little extra capacity beyond that.

[BassVirolla]

The blade design is not the fault, it is that is was not strong enough. But I also think a classic design gives more reserve in horizontal load.

Looks like the roll over blade is a solid lump bonded to a solid lump bonded to the top of the tub. You can see what appears to be the remains of a bonding agent on the stump here. Seems like a poor piece of design that meets a test but has little extra capacity beyond that.

https://i.ibb.co/hCtqMFT/image-2022-07-05-221111358.png

Probably it's only tested to compression, and under a shear load it simply got teared away. If you do a real hoop, it will never happen, because for a shear load at the tip, you will always end with a compression in one side and traction in the other. Also some shear component in both sides, but much smaller.

[Just_a_fan]

The blade design is not the fault, it is that is was not strong enough. But I also think a classic design gives more reserve in horizontal load.

Looks like the roll over blade is a solid lump bonded to a solid lump bonded to the top of the tub. You can see what appears to be the remains of a bonding agent on the stump here. Seems like a poor piece of design that meets a test but has little extra capacity beyond that.

https://i.ibb.co/hCtqMFT/image-2022-07-05-221111358.png

Probably it's only tested to compression, and under a shear load it simply got teared away. If you do a real hoop, it will never happen, because for a shear load at the tip, you will always end with a compression in one side and traction in the other. Also some shear component in both sides, but much smaller.

It will have passed the tests - but if it's been subjected to a load greater than the tests then failure is always a possible outcome.

Even a hoop will fail given sufficient load in a certain direction. And then there are the fixings and the item the fixings are attached to. Look at Grosjean's crash - that tore the car apart and ripped the tub (to expose the fuel tank) and that's the strongest item in the car after the engine block and the halo device.

[BassVirolla]

Looks like the roll over blade is a solid lump bonded to a solid lump bonded to the top of the tub. You can see what appears to be the remains of a bonding agent on the stump here. Seems like a poor piece of design that meets a test but has little extra capacity beyond that.

https://i.ibb.co/hCtqMFT/image-2022-07-05-221111358.png

Probably it's only tested to compression, and under a shear load it simply got teared away. If you do a real hoop, it will never happen, because for a shear load at the tip, you will always end with a compression in one side and traction in the other. Also some shear component in both sides, but much smaller.

It will have passed the tests - but if it's been subjected to a load greater than the tests then failure is always a possible outcome.

Even a hoop will fail given sufficient load in a certain direction. And then there are the fixings and the item the fixings are attached to. Look at Grosjean's crash - that tore the car apart and ripped the tub (to expose the fuel tank) and that's the strongest item in the car after the engine block and the halo device.

Well, when I said "will never happen" I should say "will be more difficult to happen".

Obviously, in terms of not predicted loads, there is always the possibility to break something.

[Clubman1d]

The blade design is not the fault, it is that is was not strong enough. But I also think a classic design gives more reserve in horizontal load.

Looks like the roll over blade is a solid lump bonded to a solid lump bonded to the top of the tub. You can see what appears to be the remains of a bonding agent on the stump here. Seems like a poor piece of design that meets a test but has little extra capacity beyond that.

https://i.ibb.co/hCtqMFT/image-2022-07-05-221111358.png

Probably it's only tested to compression, and under a shear load it simply got teared away. If you do a real hoop, it will never happen, because for a shear load at the tip, you will always end with a compression in one side and traction in the other. Also some shear component in both sides, but much smaller.

It has to be tested in 3 directions. Laterally, longitudinally and vertically.
Each with different forces applied.
60kN laterally, 70kN longitudinally e 105kN vertically.
And it has to have a minimum of area at a certain height. 1000mm2(?)

Sorry for the spelling.