Can carbon fibre corrode?

[bass2rez]

I was just watching the National Geographic Supercars episode about the Aventador, and wondered whether the generation of supercars made using carbon fibre chassis and body parts will be corrosion free and hence last a very long time, assuming no accidents.

It would be fantastic if we are moving into an era where the dreaded rust monster is no longer a problem.

Cheers,
Steve

Edited by bass2rez to remove typos and extra spaces introduced by Google tablet

Edited by bass2rez on Friday 12th October 23:50

[Leins]

No corrosion or degradation on any of mine after 9 years anyway. Not a carbon chassis mind you, but the roof and all the other parts are fine

[Mave]

Well, carbon fibre doesn't rust, that's for sure as it doesn't have any iron content.
Does that mean it lasts forever?
Nope.
Is it easy to spot when it's deteriotating?
Nope.
Is it easy to fix when it deteriorates?
Nope.

[CampDavid]

Ferrari Cliente car. Hmmmm

[anonymous-user]

bass2rez said:

It would be fantastic if we are moving into an era where the dreaded rust monster is no longer a problem.

Having owned Lotuses and Corvettes I can assure you it's not been a problem since 1953!! Fibreglass/composite/aluminium cars can be wondrous things without the expense of carbon fibre.

[davepoth]

CampDavid said:

Ferrari Cliente car. Hmmmm

Apparently a cut-n-shut.

-edit-

the truth is that nobody is entirely certain. Carbon fibre hasn't been used enough in vehicles that are subject to regular use to understand what the failure mode will be. Hopefully not catastrophic since they use it to make aeroplane wings.

[CDP]

CampDavid said:

Ferrari Cliente car. Hmmmm

A remarkably clean break.

Remarkable that the driver appears to be in one piece too.

Is it real?

[bass2rez]

Mave said:

Well, carbon fibre doesn't rust, that's for sure as it doesn't have any iron content.
Does that mean it lasts forever?
Nope.
Is it easy to spot when it's deteriotating?
Nope.
Is it easy to fix when it deteriorates?
Nope.

Interesting point. Do you know in what way it deteriorates?

[bass2rez]

5 USA said:

Having owned Lotuses and Corvettes I can assure you it's not been a problem since 1953!! Fibreglass/composite/aluminium cars can be wondrous things without the expense of carbon fibre.

That is true, fibreglass cars have been around for a while..

Additionally, pehaps my perception of steel cars may be old-fashioned and somewhat distorted in that I grew up owning 70's and 80's Fords, and it tended to be rust that killed them. My E36 M3 was 13 years old when I sold it a year ago, and there was not a hint of rust on it.

[davepoth]

Lucky we have particle physicists for that.

http://accelconf.web.cern.ch/accelconf/HB2010/pape...

"I'm bored. Shall we shoot stuff with the LHC?"

"Only if we pretend it's actual science!"

[bass2rez]

CDP said:

A remarkably clean break.

Remarkable that the driver appears to be in one piece too.

Is it real?

Is the nose cone section perhaps bolted to the main chassis, and separated for that reason?

[marine boy]

Carbon fibre is relatively inert so there isn't much that can break it down or degrade it. It can oxidise at high temperatures but my then most resin systems have died way before this.

Some resins can degrade with exposure to UV light, water absorption and heat which will effectively degrade the carbon composite part as the resin is the matrix that binds all the carbon fibres together to create a strong and stiff structure.

I guess super cars could one day eventually corrode in places if it's been built using alumnium honeycomb in the structural panels. Or through galvanic corrosion between any alumnium inserts and carbon fibre skins if they not protected by a ply of glass fibre.

As for a picture of the Ferrari I'm pretty sure the failure was not cause by fatigue but was a bond joint failure caused by the impact to a wall. It was not a cut and shut job as some have suggested.

Edited by marine boy on Saturday 13th October 00:07

[bass2rez]

davepoth said:

Lucky we have particle physicists for that.

http://accelconf.web.cern.ch/accelconf/HB2010/pape...

"I'm bored. Shall we shoot stuff with the LHC?"

"Only if we pretend it's actual science!"

Does that report mean that continued and repeated scanning by speed cameras will weaken the carbon fibre structure? Cunning...

[mat777]

From what we've been taught about environmental and age degradation of composite aircraft parts:

• resins can deteriorate with age and crack or crumble. so can the glue between separate parts
• vibrations can cause fasteners to wear fixing holes oversize very quickly

the most pressing concern however is that the layers of carbon weave can delaminate either through age or imperceptible impact damage (such as, say, a big stonechip or dropping a spanner). When this happens to hollow structures such as a monocoque, it is impossible to tell the extent of the damage, or even if there is any. What is also impossible to tell is how the structural strength is affected.

So, for a car, multiply a few huge potholes/speedbump grounding with many years and one day it might just fall apart.

[davepoth]

5 USA said:

Having owned Lotuses and Corvettes I can assure you it's not been a problem since 1953!! Fibreglass/composite/aluminium cars can be wondrous things without the expense of carbon fibre.

Corvettes and Lotuses aren't fully stressed composite monococques though. Even the Lotus Elite, which was partially stressed (some steel structural components) had issues with suspension mounts tearing out of the car.

[GhepardoGTS]

I once visited a massive CF factory in Malaysia that produces various carbon winglets for some obscure aircraft such as the A380 and 787 Dreamliner. The experts told me that only few materials in this earth absolutely do not expire, and he was talking about diamonds and gold. So the answer is yes, CF do corrode depending on various circumstances.

Most troubling is CF's complete lack of repairability. I was once amazed of a story of how a burnt Jaguar racecar was restored to Concours conditions. Of course some sort of technology may eventually emerge in the future, but for the time being, if a carbon monocoque supercar suffers cracks or even deep scratches, it's done. It's like having a hole in a sweater. You just know fibers are untangling themselves out of sight.

[JonnyVTEC]

Foam or sandwich cores can absorb and trap water. Delamination insider the ply it difficult to find and monitor.

Wishbones on tubs etc bolt to inserts, typically ally so you have to control the material contact otherwise a galvanic cell will be created and corrode the ally and risk pullout from the carbon structure.

UV is a good one, that of course the effect on the resin in the composite rather than the actual carbon.

[marine boy]

GhepardoGTS said:

if a carbon monocoque supercar suffers cracks or even deep scratches, it's done. It's like having a hole in a sweater. You just know fibers are untangling themselves out of sight.

sorry not meaning to be rude but what a load of olde bks

[JonnyVTEC]

It's pretty tolerant to cracks to fair. The non homogenous structure means it stops crack propagation inherently and has a degree of stress relief.

Delaminates between the plies is the concern as its only interface is the strength of the resin to start with.

[mat777]

marine boy said:

GhepardoGTS said:

if a carbon monocoque supercar suffers cracks or even deep scratches, it's done. It's like having a hole in a sweater. You just know fibers are untangling themselves out of sight.

sorry not meaning to be rude but what a load of olde bks

Its pretty true actually marineboy, I've sat in lectures about damage propgation on CF structures and been round the Airbus A400M CF wing assembly line. They say that if one worker drops a spanner on the CF wingbox its a writeoff as it only takes one crack to start the delmaination, and some vibration to propogate it and finish off the entire structure (and you really dont want your wings falling to bits). Granted its nowhere near as serious on a ground based car, especially as most of the panels on it arent structural/loadbearing like on an aircraft, but it still applies in principle to the carbon tub chassis.

2 or 3 years ago the next big thing, being researched right here at the Bristol Uni ACCIS (Advanced Composites Centre for Innovation and Science) was going to be self-healing carbon with hollow fibres containing air-hardening resin, so that when damaged they formed a scab of glue to fix themselves. Unfortunately I think they have since given up because its just damn near impossible to make reliably/accurately with today's methods and technology in such a way that it is guaranteed to work every time

Edited by mat777 on Saturday 13th October 00:24