I dunno if this is crazy or not, but I'm wondering if any company has duplicated the exact panels for an S2000 in aluminum instead. Seems like you could save a metric F-ton of weight this way. I'm guessing that the hood is the only piece that is aluminum (which is little consolation given that I slammed it on my finger today) but if you replaced them all it seems like the weight balance would be retained.

Might not be that expensive to take them to a shop that works with aluminum and have them just clone it.

Thoughts?

 

^The hood is not coupled to the steel body/frame electrically. Mixing the two, since the body panels are a integral part of the frame rigidity (meaning they have to be welded/bolted on) the galvanic corrosion due to two dissimilar metals being electrically coupled would be terrible!

~If a small scratch develops youre just asking for a rust spot.

 

The only other "panels" on the car are the fenders... the bumpers are rubber, the door panels are all integrated and are a safety risk if someone T-bones you, and the rear quarter is part of the frame. I suppose you could do the trunk but might as well go with a CF trunk and paint it.

 

steel welded / bonded directly to aluminum will likely cause a great deal of corrosion at the interface unless you're able to completely isolate the two. with the vibrations of a car, fretting would be a potential problem nearly anywhere. so what do you isolate the two metals?

bolts/rivets with an isolating layer are hard. you can't just coat half a steel bolt with zinc and call it good--then the bolt will corrode and fall apart. you could do dielectric fasteners, but those aren't thoroughly proven yet.

if you propose using structural adhesives, i personally wouldnt go near it. that can be done and can work great, but there are a host of failure modes that must be all considered correctly. vibrations, fretting, poor or unreliable/inconsistent manufacture, potential for peeling due to corner stresses/shear/etc, and whatever else. and the failure mode is brittle, which is hard to inspect and not exactly graceful if it goes. and if you expect the end user to do it...

that's part of why we don't see more aluminum in cars--it's hard to replace selected parts with aluminum while leaving others steel since you have to isolate the two thoroughly.

i've never heard of it done though, to answer your question. if your company was to briefly consult with a PhD level corrosion expert before undergoing such a project, it would probably save a lot of wasted time, effort, and money. and you're right, aluminum would save a lot of weight.

but fiberglass is likely a much easier answer to the same question, especially considering the low production volumes you'd start with.

 

aluminum does oxidize but it does not "rust". it will form a layer of aluminum oxide and then cease to oxidize further.

 

That is true of many circumstances, but once the aluminum is perturbed it will reoxidize. This probably won't create problems for largely unloaded sheets, but for structural metal that sees regular tension cycles, any cracklike discontinuity (a scratch, a bad weld, bad geometry, whatever) will open and reopen with localized plastic strain that will increase over time as the tiny corroded area (crack) very slowly grows. Fretting / rubbing would also cause the wounds to reopen. For that reason, the attachment point is the most prone to attack, since loads will travel through there.

The life of the panel may be long enough that this is not an issue in most areas of the country, but it is a real potential problem with aluminum on steel that should be evaluated.

 

I thought our cars come standard with aluminum body panels.

Edit: Nevermind. I was wrong