Richard Mille

BDLJ
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CFRP

Hi Anthony,

It has been years since I had anything to do with composites, so this is just a rough guide.

The benefit of CF is its strength to weight. Optimised designs for CF attempt to ensure that the CF strands are placed in tension ( the rope principle: you can drag a boulder with a rope, but can't push a boulder with a rope... )

If you had a piece of CFRP that had all its fibres going in one direction, then that would be nice and strong/stiff in that direction, but pretty useless if you loaded it at 90 degrees to the direction of the fibres. Hence why you have weaves at 0/90 degrees, you can layer these such that the material is strong across many directions.

There are a multitude of weaves as well, with different patterns to the fabric, to optimise various properties (for example how flexible the fabric is before resin is added, or how smooth or lumpy the fabric is)

Finally, there are different grades of fibre themselves, with the standard stuff about half the strength of the super-duper stuff. As usual, the stronger the material the greater the tendency to brittleness, so it will have a greater tendency to shatter on impact.

So without knowing exactly what grade of fibre used, nor knowing the resin, nor the layering, it's hard to say which of your examples is best, all depends on the application.

BMW doesn't (as far as I know) use anything special, but they do use a manufacturing process that allows (reasonably) large mass production.

NTPT is a process for very thin unidirectional sheets - hence its application in sails (as a watch material....who knows ;-)

Forged carbon just uses lots of chopped up strands randomly distributed though the polymer and pressed into a mould. Not the best way to take advantage of CF's properties.

(That's enough now for this rainy morning )