What's the next carbon tub step change?

[SidSidney]

Just like aluminium monocoques before them, carbon tubs revolutionzed stiffness and safety when they arrived in the McLaren MP4/1.

What's next in chassis design?

Is there something esoteric in aerospace development that could make carbon fiber composite look old, tired and sloppy?

[furious_g]

My guess would be something 3D printed - in what material I'm not sure - the technology isn't good enough currently to do a stiffer/lighter tub than what can be produced with carbon and various honeycombs.

3D printing will allow precise control over shapes which cannot be made conventionally. Things like a complex internal latice-work will be possible, allowing the designers to create a stiffer structure for less weight.

Also, I wouldn't be surprised if we're really starting to get into the area of diminishing returns with chassis stiffness and weight. Sure, they can be stiffer and sure, they can be lighter, but in terms of actual lap time difference I doubt there is much in it. Let's say they could increase stiffness by 20% and reduce weight by 20% (allot by F1 standards) I doubt you would see more than 0.1s laptime difference. Therefore it won't be pursued as aggressively as aero or engine development.

[Just_a_fan]

The benefit of a light component is that you can add ballast lower down to bring the car up to minimum weight. The tub is already pretty light and the cars are close enough to the weight limit that there's probably little to be gained from trying to shave off a few grammes from the tub. You could make the tub walls thicker by using some super light weight core material to give more stiffness for the same weight but that would have an aero effect (wider tub).

Perhaps using an aerogel core could give you a lighter tub than the usual nomex honeycomb but I'm not sure that it'd be worthwhile.

[SidSidney]

A few years ago I was considering building a space frame chassis for Formula Ford using genetic algorithms I had seen used on space truss designs.

I had seen an article about some work going on at Southampton, they had optimized a space truss design from this:



to this:



And in doing so increased torsional stiffness drastically.

I was really struck that you could take a junior car to another level with some bizarre-looking spaceframe that was actually amazingly stiff. Surely there would be constraints, but optimization programmes allow for constraints (I have experience from another sector).

I would still be interested in funding that project, if anyone is interested in the CAD and FE side of things.

[WaikeCU]

Carbotanium tubs?

[andylaurence]

A few years ago I was considering building a space frame chassis for Formula Ford using genetic algorithms I had seen used on space truss designs.

I had seen an article about some work going on at Southampton, they had optimized a space truss design from this:

http://www.southampton.ac.uk/~ajk/truss/3dbeam1.gif

to this:

http://www.southampton.ac.uk/~ajk/truss/3dbeam2.gif

And in doing so increased torsional stiffness drastically.

I was really struck that you could take a junior car to another level with some bizarre-looking spaceframe that was actually amazingly stiff. Surely there would be constraints, but optimization programmes allow for constraints (I have experience from another sector).

I would still be interested in funding that project, if anyone is interested in the CAD and FE side of things.

That's very interesting. Spaceframes still win at club level because they're dead cheap to manufacture and repair. Many people are moving to carbon tubs, but not many are going faster. If someone wants to do the CAD/FE and you want to fund that, I'll run the car and drive it...

[Tim.Wright]

Given that most parts of the car have the materials restricted by maximum specific modulii in the regulations etc there is not the possibility anymore for F1 to discover or develop any wonder materials.

As it is, there are material suppliers which who make a specific grade of aluminium which exists only to satisfy the regulation of the maximum specif modulus in the F1 rules.

[Writinglife]

Surely the next step won't just be making it stiffer and lighter, but also able to absorb more impact and distribute impact shock so that the driver is more protected in a crash?

[Tim.Wright]

I had seen an article about some work going on at Southampton, they had optimized a space truss design from this:

http://www.southampton.ac.uk/~ajk/truss/3dbeam1.gif

to this:

http://www.southampton.ac.uk/~ajk/truss/3dbeam2.gif

And in doing so increased torsional stiffness drastically.

Do you have a link to that article? There is something about that doesn't make sense about that final design. One being that for a structure under a pure torsional load, there is no reason to have a varying cross section. Perhaps if it is undergoing other loads along its length then maybe....

[Pierce89]

I had seen an article about some work going on at Southampton, they had optimized a space truss design from this:

http://www.southampton.ac.uk/~ajk/truss/3dbeam1.gif

to this:

http://www.southampton.ac.uk/~ajk/truss/3dbeam2.gif

And in doing so increased torsional stiffness drastically.

Do you have a link to that article? There is something about that doesn't make sense about that final design. One being that for a structure under a pure torsional load, there is no reason to have a varying cross section. Perhaps if it is undergoing other loads along its length then maybe....

Well they did call it a truss, so I doubt that its pure torsional loading.

[SidSidney]

Here's the page:

http://www.southampton.ac.uk/~ajk/truss/welcome.html

It was a long time ago, it seems I can't find the bit about stiffness, more frequency response in this article, I but I am fairly sure I was interested for other reasons. I do recall emailing Andy Keane and looking at it seriously for a while, somewhere around here I have a spaceframe model in AutoCAD.

It is interesting how the 2D truss looks like a bone, that's what got me thinking about it.

[Edax]

A few years ago I was considering building a space frame chassis for Formula Ford using genetic algorithms I had seen used on space truss designs.

That's already old stuff . The topology optimisation packets have advanced quite a bit recently,

A350 wing box (isogrid)


EOS/Altair antenna bracket


bracket (Airbus?)

It is fascinating stuff, especially combined with the freedom of 3D printing. And it certainly is used today in F1 and will be used more extensively in the future. But I'm not sure whether this would work for tubs. These kind of methods excel when you have a relatively simple mission profile. A static load, torsion, vibration mode, something like that. It then optimizes the structure for that specific loading case. However in doing so it often creates weak spots with regards to other loading cases. Some post tweaking is usually needed to make sure that it is actually usable.

Since the tub has to withstand a great variety of different impact, vibration and loading scenario's, I wonder whether the modelling as wel as computing power is advanced enough proces and converge on such a problem.

And it might well the be the case that the supercomputer, after devoting all it's processing power looking at the problem for a long period of time, ends up telling you you need to make the tub a a box structure. After all, despite 2000 years of science, the wheel is still round.

[SidSidney]

http://resources.altair.com/Corp/images ... racket.jpg
EOS/Altair antenna bracket

It is fascinating stuff, especially combined with the freedom of 3D printing. And it certainly is used today in F1 and will be used more extensively in the future. But I'm not sure whether this would work for tubs.

That bracket is very sweet, what a beautiful piece of work. I can totally see a spaceframe designed in that fashion - even though I know they are old hat now with the newer series like F4. What about making the suspension A arms in that optimized manner?

I wonder about tubs. What would you do differently if you could 3D print a whole tub? What curves and bumps, thicknesses, rotations in the material, maybe even resonant tuning spots, could you build in in odd positions - like that antennae - if it didn't make things more complicated? What shapes would we see that might make the car almost literally "sing" due to it's frequency response? Would we get track specific tubs? Aroperly asymmetric tub designs? Ribs and skins?

Some interesting stuff, I am sure there is a step change coming from some direction, and it may not be materials.

[Lycoming]

I wonder about tubs. What would you do differently if you could 3D print a whole tub? What curves and bumps, thicknesses, rotations in the material, maybe even resonant tuning spots, could you build in in odd positions - like that antennae - if it didn't make things more complicated?

Sounds like you're just adding stress concentrations.

Then again, I've seen topology optimization results for a tub that had criss-crossing uni tapes all over it, something like a spaceframe on the inside skin of the tub, but you don't need 3D printing for that. The advantage there would be primarily be, I'm guessing, if your torsional stiffness requirement greatly exceeds your side impact requirement.

Topology optimization, at least in the results I've seen, tend to produce truss-like structures. Note that I say this without a real understanding of how the algorithm actually works; it's just an observation based on a handful of results.

Would we get track specific tubs?

Unlikely. Too expensive and time consuming to design, build and crash test them all, and little if any benefit to be gained.

Aroperly asymmetric tub designs?

Probably not unless the calendar becomes mostly ovals.

Ribs and skins?

They already have bulkheads (kind of like ribs) inside the monocoque (skin). But I doubt they would move to proper semi-monocoque construction like on aircraft; it's probably not safe for cars.

[riff_raff]

I think we'll see more use of stitched and woven 3D textile preforms that use resin infusion.