carbon fiber composites
 

I know there are quite a few here in engineering and some in finance, not to mention that most are interested in sports cars...

Here is an interesting article that unites those interests:

Carbon Fiber

BTW - lignin is used in the oldest composite material of all

RE: Carbon Fiber’s Move into the Mainstream

Someone should find a way to combine 3D Printers with Carbon Fiber.

Maybe flash setting resin and a pile of CF?

Use a Lazer to set the resin?

I did a lot of damage assessment studies on CFCs back in the mid 80s. Some parts that we were told were samples turned out to be panels off of operational aircraft that the Air Force wasn't yet admitting the existence of.

Making actual carbon fiber to meet structural requirements (not just look pretty) is very involved and is beyond the average layperson's capability. Just ask the Iranians.

Back when I was at McDonnell Douglas, I was involved in making carbon fiber panels for some ill-fated solar power system. Very complex.

We actually do a lot of carbon fiber research here at work (but I'm not involved):

from: Oak Ridge National Laboratory - Oak Ridge establishes carbon fiber composites consortium

I've worked with carbon fibre using advanced composite materials and processing for over 20yrs :eek: (reading this makes me feel old).

There has been some cross over from racing cars to production road cars but its still very limited with the number of parts used and where. One volume manufactured part is the carbon roof panel used on the BMW M3.

Today most of the hyper road cars still use hand laminated materials and pressure cured manufacturing methods. Basically the same as used 20yrs ago on the first carbon fibre production road car, the McLaren F1. This was made using F1 racing materials and techniques with some productionisation but every stage was done by hand without any automation.

McLaren probably still lead the way on volume and manufacturing speed for production road cars. They developed their manufacturing techniques with a composite company in Austria. This company will also manufacture the 918 chassis for Porsche.

To reduce costs and speed up manufacture I think the future will be in the form of 3-D woven pre-forms placed in a self heating press with quick cure thermosetting injected resin. Part finishing will be done be CNC machining, water jet cutting and then bonding will be done by robots.

Or for really simple parts precured thermoplastic panels stamped and cut in the same way steel panels are done.

is the resin injection process time-consuming?

The new 2013 NASCAR "Stock cars" have carbon hoods and trunk lids I read today in Autoweek.

Do carbon tubs fatigue over time? Just thinking about all these supercars with carbon tubs and whether they will be usable in some number of years. I can't imagine the replacement cost for a tub in 25 years for a 918.

very long life

Yes they fatigue, just like anything else, however life and performance can be prolonged obviously with proper design. While I suspect the epoxies continue to get better, they can be subject to UV degradation if unprotected which can lead to premature failure / diminished structural properties.

I remember the early carbon fiber fishing rods when under presure went bang like a gun when they had had a certain number (not that many) of hours in the sun.

Good question, I thought they just vacuum bagged it as done with fiberglass cloth.

The Joint Strike Fighter F-35 program I saw on PBS several years ago featured the two finalist being prototypes being made. The top wing section of one of the planes was a large single piece of CF which had to be autoclaved. They had several mishaps and were leaning something new with every failure.

An invention a day is how they put it.

Just out of college I worked for a pultrusion (composite analog to extrusion) company. If it was constant cross section, we could make it, in any length you wanted. We made parts for the Stealth Bomber, telescoping masts for the Army, a towline for the Navy, tubing for Kestrel, arrows for Browning and the death of the company, hockey sticks for Bauer, one of the first. Instead of taking the $5M, 3 year contract, the owners sold the entire company to Bauer and moved it to Canada.

I managed the business side of the company way back in 1993, if we had stayed in business, I would have had an entirely different life, but composites have stayed with me and will be getting back into them. Just have to learn all the latest fabrication techniques.

Question/concern about using carbon panels in mass quantites on street vehicles:

How would they react to your everyday fender-bender/dents? My understanding is that the panel would either completely shrug off the hit without damage or be rendered destroyed/unrepairable.

Is this a good assumption? If so, wouldn't this have an adverse affect on insurance prices?

the panels shatter (absorbing the crash impact energy) - you would then have to replace those panels

BTW - the reason I asked about the resin injection process is that I was wondering if the technology used for #D printing could be adapted to save some $$ on that step.

I am also curious about Fiber Forge (used to be a low cost CF designer/manf'er)

Is it not possible for a panel to deform without shattering? Obviously if you crunch something heavily and have metal panels, they are junked as well. Or are CF panels more of a binary condition, where they're either perfect or junk?

One thing to note about carbon fibre hockey sticks - players make sure there are no nicks or any minor looking surface damage before taking their next shift on the ice. If not, they risk having the shaft literally explode on their next shot. We've all (hockey fans) seen that happen too often.

Cheers
JB