I don't see anything about "30% carbon fibre", nor an explanation of "carbon fibre composite".
Enya says "[FONT=Verdana,Arial,Tahoma,Calibri,Geneva,sans-serif]Carbon Fiber (30%) & PC"[/FONT] in the specifications, and "carbon fibre composite" is just about any use of carbon fibre.
Carbon fibers are essentially just threads (hence "fiber") of graphite and aren't very structural on their own. They are almost always used in a composite to reinforce some kind of resin or epoxy
Typically carbon fiber is woven into a fabric, laid into the mold in several layers, and then infused with the resin under a vacuum.
A carbon fiber fabric will drape and stretch like other fabrics (how much and in which directions depends on the specific weave) before it's infused with resin
.
This gives the stereotypical woven look and is very strong and stiff: most of the structure is the carbon fiber and the multiple layers of fabric reinforce each other.
This process can be used with other fabrics as well: aramid (Kevlar) and fiberglass composites are common, with the different sorts of fibers having different strengths and weaknesses. Blackbird's moved away from carbon fiber and now uses a natural fiber cloth ("[FONT=Verdana,Arial,Tahoma,Calibri,Geneva,sans-serif]Ekoa®"). I suspect you could get good results for a ukulele with cotton island prints.[/FONT]
The Enyas and Outdoor ukes don't use a fabric weave. They use injection molding to create a polycarbonate (PC) body with (I believe) carbon tow or glass fibers loose in the polycarbonate mix. Since there's both PC and the fiber fill this is still a composite. It's just a higher ratio of plastic:fiber than a vacuum infused weave and will end up thicker and heavier for the same strength.
In both cases (the fabric or the loose tows) you end up with a carbon fiber reinforced resin, but just with different levels of reinforcement and so different stiffness, strength, and weight factors.[FONT=Verdana,Arial,Tahoma,Calibri,Geneva,sans-serif]
Outdoor claims their carbon versions are 50% stronger (they probably mean stiffer) and 15% brighter than their fiberglass versions, and they do sound different: [FONT=Verdana,Arial,Tahoma,Calibri,Geneva,sans-serif]https://youtu.be/ahhXO8MMg7M . Even so, I expect that using CF in a uke like this is mostly for the marketing: Carbon Fiber is sexy and draws eyes to the instrument. It works on me - I have both a Klos and an Outdoor Carbon. Those were enough that I resisted the Enya
[/FONT]
[/FONT]