Thread: aramid fiber
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Old February 2nd 18, 02:35 AM posted to rec.bicycles.tech
John B.[_3_]
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Default aramid fiber

On Thu, 01 Feb 2018 04:58:54 +0100, Emanuel Berg
wrote:

IIUC aramid fiber is when you not only use
carbon to reinforce the plastic (which is
ordinary carbon or CFRP) you also use aramid
("aromatic polyamide") which is synthetic
polymer perhaps in the nylon rope sense, and
this carbon/aramid reinforcement combination is
what makes the material "composite", and this
material has been commercialized using
para-aramid under the name Kevlar.

Anyone ever make a bike out of it?

I just saw it on a hockey stick, the
CCM RIbcore 40K. Unfathomably, they didn't put
the weight on it (the stick), but I checked it
myself and it weighs 435g, compared to my old
stick, which is wood with glass fiber on the
blade only, and that is 805g (including tape).
Also, the new stick was 1299 SEK
(1299.00 SEK ~= $164.97 | £116.13 | €132.76)
which in the hockey world isn't expensive.

So the material seems to be cheap and light
enough, perfect for bikes in other words?
BTW how much is a typical medium-level CFRP
frame in grams and dollars? We can compare the
expensive bike world with the expensive hockey
world...


I suspect that it may be at least partly to the loading of the device
(the direction and amount of force applied to a device). Kevlar, that
you mention has tremendous tensile strength - The specific tensile
strength (stretching or pulling strength) of both Kevlar 29 and Kevlar
49 is over eight times greater than that of steel wire. But on the
other hand it has very poor compressive strength (resistance to
squashing or squeezing). Rather difficult to design a three
dimensional device using a material that has strength in only one
direction :-)
--
Cheers,

John B.

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