Frame material in F1, Carbon Fibre or Titanium?

[ChipAyten]

No parts of the car may be made from metallic materials which have a specific modulus of elasticity greater than 40GPa / (g/cm3). Tests to establish conformity will be carried out in accordance with FIA Test Procedure 03/02, a copy of which may be found in the Appendix to these regulations.

So you're saying the car cannot be made from gold or lead? shucks

[Richard]

So you're saying the car cannot be made from gold or lead? shucks

Are you sure about that?

Gold modulus = 70 GPa, density = 19.3 g/cm3. Hence specific modulus of density = 70/19.3 = 3.6.

The rule forbids berylium. Click on this link and then click on the column header "Young's modulus over density" http://en.wikipedia.org/wiki/Specific_m ... _materials

[godlameroso]

would a titanium monocoque be worth it? Im an aero guy idk much about materials.

[Tommy Cookers]

if it was thick enough not to wrinkle like a beer can it would be relatively heavy
a magnesium alloy would be the best metal of those allowed (lighter), but embarassingly flammable (Schlesser etc crash)
(its low density would allow maybe twice the wall thickness, and be much lighter than Ti)
some military aircraft have used major amounts (Vought)

but still less stiff or heavier than CF

[thisisatest]

Why did they ban MMCs, but then make a special allowance for silicon carbide aluminum MMC? Am I right in interpreting silicon carbide aluminum matrix composite as MMC?

[PlatinumZealot]

Might be because they fail without warning...and are hella expensive to cast in big pieces. Remember those early nineties garret turbos withd the ceramic wheels? They used to break.

[thisisatest]

MMC does not imply ceramic. The item or items in the aluminum may be ceramic, but they don't have to be. I'm not familiar enough with ceramic impeller turbos to know if the ceramic impellers were coated, ceramic mmc, or completely made of only ceramic. I understand they generally failed when some foreign object got in there and the fan struck the item, and that most applications then used a particulate filter to counter that.
So my question still stands. Specifically, what's wrong with boron carbide aluminum MMC? I know it was originally a cost-control measure. I understand that development of materials to replace MMCs when they were banned ended up costing a lot more than the original MMCs.
So what's up?

[Jersey Tom]

I understand that development of materials to replace MMCs when they were banned ended up costing a lot more than the original MMCs.

Have they? Which materials? And funded by what organization(s)? Are teams really using any amount of steel, aluminum, and titanium alloys absolutely specific to F1?

[thisisatest]

It's true, I read it on the internet.
Seriously, I searched for my source and came up empty. Knowing where a good portion of my technical f1 info comes from, it was probably from an article in Racecar Engineering or Race Tech from a few years ago. I recall there were a few specific metal alloys listed, but it's also possible the author was painting a picture with broad strokes. If I find it, I will certainly post it.
Greg

[Pierce89]

I understand that development of materials to replace MMCs when they were banned ended up costing a lot more than the original MMCs.

Have they? Which materials? And funded by what organization(s)? Are teams really using any amount of steel, aluminum, and titanium alloys absolutely specific to F1?

I read the article he's referring to. The extra cost was because they started trying to design parts from standard alloys that still had the same weight and performance as mmc's

[PlatinumZealot]

MMC does not imply ceramic. The item or items in the aluminum may be ceramic, but they don't have to be. I'm not familiar enough with ceramic impeller turbos to know if the ceramic impellers were coated, ceramic mmc, or completely made of only ceramic. I understand they generally failed when some foreign object got in there and the fan struck the item, and that most applications then used a particulate filter to counter that.
So my question still stands. Specifically, what's wrong with boron carbide aluminum MMC? I know it was originally a cost-control measure. I understand that development of materials to replace MMCs when they were banned ended up costing a lot more than the original MMCs.
So what's up?

I am trying to imagine how a panel made of carbon fibres with aluminum/magnesium alloy, will be advantageous to CFRP... It might be in strength and certain conditions where brittleness is undesirable....

I was thinking of metal fibres or even carbon fibres with ceramic as the matrix.. I must admit this is what I though MMC was at first. Which is wrong when I read wikipedia. The matrix is usually a metal.

[flyboy2160]

...
I am trying to imagine how a panel made of carbon fibres with aluminum/magnesium alloy, will be advantageous to CFRP... It might be in strength and certain conditions where brittleness is undesirable...

you wouldn't want to use an aluminum MMC in an F1 (body or tub, i'm assuming) panel. it would be hideously expensive and offer no advantage over a well designed FRP (Fiber Reinforced Plastic) sandwich panel. look at the cut in half Sauber(?) and see how many of the load bearing tub pieces are sandwich panels. (you typcially don't want a monolithic panel if you're going for a stiffness-driven design.)

the advantage for MMC (and metal) over FRP in a part or fitting comes when you have concentrated loads changing direction rapidly in a complex, relatively compact part.

except for a few bold designs - such as from Airbus - FRP parts generally have a metal fitting where the load becomes concentrated. there is an excellent thread here on this site showing cutaways of an F1 suspension arm and the transition from FRP to the metal end fittings.

you could use a cast MMC in something like a suspension upright. but it would be expensive to cast and to machine. a typcial aluminum MMC reinforcement is silicon carbide (SiC). but almost always you can't use regular cutting tools (which are the same material), so you end up using diamond coated tools. the teams have used 3D Ti for these instead........

an excellent use of alumiinum MMCs is in extruded aluminum shapes that are fastened together. i worked at a company that used this idea for a couple of avionics racks where stiffness was critical. the extra stiffening of the aluminum by the Sic was important. the amount of maching by special tools was minimized.

[aussiegman]

Do not forget that aluminum and carbon fibre do not generally work well in close proximity due to issues with galvanic corrosion as laminates reinforced with carbon fibers can induce galvanic corrosion in attached aluminum structures.

You can protect the aluminum through anodizing and plating however it remains an issue to be considered.

[tathan]

Might be because they fail without warning...and are hella expensive to cast in big pieces. Remember those early nineties garret turbos withd the ceramic wheels? They used to break.

I have no source but anecdotal, but I thought they didn't used to break per se, rather the bond between the shaft and ceramic wheel was failing and the wheels were coming off under torsion (e.g. during gear changes) and people were just seeing bits everywhere and assuming the ceramic had shattered.

Your point still stands though, just thought I'd add my tuppenth

[flyboy2160]

Do not forget that aluminum and carbon fibre do not generally work well in close proximity due to issues with galvanic corrosion as laminates reinforced with carbon fibers can induce galvanic corrosion in attached aluminum structures.

You can protect the aluminum through anodizing and plating however it remains an issue to be considered.

yes, sir, there certainly is a galvanic corrosion problem when aluminum and carbon fiber are in contact and when water is present.

in the non-space aerospace projects i've been on, even anodizing or plating the aluminum wasn't enough. usually one to three plies of fiberglass are required in the carbon composite where it will contact aluminum. you even have to consider the material of fasteners passing through both materials!

but anodizing won't work if the aluminum will be bonded to the carbon fiber composite because the adhesive won't bond to anodizing (which is a ceramic). this is one of the reasons that titanium is used for bonded-in fittings (but it has its own set of bonding preparation issues.)

but i've seen more than one F1 chassis cutaway using sandwich panels consisting of aluminum honeycomb core and graphite skins - even though polymer cores are available. aluminum core/graphite skin is a very stiff construction. i'm guessing they get away with it by assuming the the life of the structure is too short for the corrosion to degrade the structural integrity.