costing carbon/kevlar

[TG]

We are using a carbon kevlar braid as reinforcement for carbon panels. How would we go about costing this? What I suspect right now is that since the cost report layes out graphite composite as $100/lb and non-graphite composite as $40/lb, we would cost the material by percentage by weight of each to the respective cost. Can anybody tell me if this is right?

[TG]

We are using a carbon kevlar braid as reinforcement for carbon panels. How would we go about costing this? What I suspect right now is that since the cost report layes out graphite composite as $100/lb and non-graphite composite as $40/lb, we would cost the material by percentage by weight of each to the respective cost. Can anybody tell me if this is right?

[Michael Jones]

That's a tricky one - highlights the ridiculous nature of the rule, really, since obviously the price of interweaved CF/Kevlar is neither some average of the two or $100 (or $40) a pound.

I'd do as you're suggesting here and separate the CF from the Kevlar if you can.

Might be hard to do, since manufacturers usually don't give separate weights or ratios of each strand type, as I can recall.

[TG]

Thanks Michael. I know the rules are really ridiculous. I know of an exception that will probably get them to change the rules. Hopefully I'll be able to get away with it for a couple of years http://fsae.com/groupee_common/emoticons/icon_smile.gif

Aside from that, we aren't using too much carbon kevlar. It's just like a woven thread of material maybe a millimeter in diameter. A pic of it is here (http://www.vyatek.com/VYATEK/BiFusion_nojava.php). This stuff acts like an I-beam for a tube, which is explained here (http://www.vyatek.com/VYATEK/dox/IsoGridIntroduction.ppt). The guy that owns the company is a former ASU SAE member and he either knows what the percentage by weight of the carbon kevlar or can find out, as it is made especially for him.

[CMURacing - Prometheus]

is one of those techs (exogrid i think) the stuff they made a crazy bicycle frame out of at InterBike 2004? it was a composite tube frame, but the tubing was all like a mini-truss structure. pretty cool shit.

[TG]

If it was a Titus bike, then yes. Howard is now the owner of Titus. Santana also uses it for tandems as well.

The tech has been licensed to Porsche and Ferrari. I think it's been used in the construction of Ferrari's Ti/Carbon gearbox, except inside out compared to the exogrid. But I'm not 100% sure, I'm just sticking 1 + 1 together and hoping it will be right.