CFRP Processing

[MightyJ]

Hello all,
I have been searching for information about processing CFRP and am having trouble finding things over the internet. Just about anything will help. Does anyone have any good information sources on the topic?? That should be all I need, thanks a ton.

 

[RPstress]

You'll probably have to narrow your focus quite a lot to get any useful help. You (almost) might as well ask for information on "processing metal."

Are you interested in processing prepregs in an autoclave? Infusing a dry preform under vacuum? Resin transfer moulding into matched metal tools? Injection moulding short fibre-reinforced thermoplastic?

Some idea of the application area would be sensible. Is the eventual target structure a boat hull? A 50 meter wind turbine blade? A fishing rod? A model airplane wing? A satellite waveguide?

For really general information the 'standard' references such as Niu's composite airframe book or the Concise Encyclopedia of Composite Materials (ed. Kelly) can provide some very general background.

Other people might have favorite manufacturing references (personally I don't). You really should be able to find a lot from Google books and from university websites.

I think that unless you can refine your query then you're asking a bit too much.

 

[MightyJ]

Thanks for your reply, those sources may be enough if I can find them. As for an application, I am designing a layer of a pole vault. It may be woven CFRP in an epoxy resin. I am also researching wrought magnesium alloys and its processing.

 

[SWComposites]

http://composite.about.com/

http://www.compositesworld.com/

ASM Handbook vol 21 Composites:

http://asmcommunity.asminternational.org/portal/site/

http://www/AsmStore/ProductDetails/?vgnextoid=d56253501f0f8110VgnVCM100000701e010aRCRD

 

[RPstress]

Useful links from SW. I'd forgotten about ASM 21 (even though there's copy in the cupboard). There's a lot of good info in it, with quite a lot about manufacture.

For making just one or a few off of a pole it might be enough to hand lay onto a male mandrel and cure with moderately elevated temperature and shrink-wrap on the outside for consolidation. The external surface won't be wonderfully smooth but presumably that won't matter too much. I seem to remember they made the wing spar for Gossamer Condor man-powered aircraft that way. Not sure how they got the tube off the mandrel after cure. If it was aluminium it would expand as the shrink-wrap shrinks and might just shrink enough after cure to be removed reasonably easily.

If you want to make a lot of poles it might well be tempting to pultrude them.

For a long time pole vaults have been glass (I assume S-2 glass or similar for high-end competition). Mixing in some carbon in might be slightly dodgy from the point of view of strain to failure; 2.3% for the highest performing (expensive) carbon fibre and getting on for 5% from good, carefully handled, glass.

I can see carbon being used for a smaller diameter pole where the stiffness means that a smaller section can be stiff enough in bending and can still see high curvatures because of the lower strain for a given curvature (smaller distance to the extreme fibre).

The flexure strains glass pole vaults see in use will need quite a high-performance resin from the point of view of strain, for much repeated use.

Interesting design problem.

The traditional jumping off point (sorry) for mag alloy is MIL-HDBK-5, though the material in there is pretty old and conservative by today's standards.