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aramid fiber

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Emanuel Berg

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Jan 31, 2018, 10:58:58 PM1/31/18
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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...

--
underground experts united
http://user.it.uu.se/~embe8573

AMuzi

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Feb 1, 2018, 9:24:47 AM2/1/18
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On 1/31/2018 9:58 PM, 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...
>

Aramid-Kevlar strands in carbon frames was a breakthrough
concept in 1986:

https://en.wikipedia.org/wiki/Kestrel_USA

better known in other products:
https://www.youtube.com/watch?v=Hyn7eKfQXPg


--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971


John B.

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Feb 1, 2018, 8:35:44 PM2/1/18
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On Thu, 01 Feb 2018 04:58:54 +0100, Emanuel Berg <moa...@zoho.com>
wrote:
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.

Emanuel Berg

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Feb 1, 2018, 9:19:10 PM2/1/18
to
John B. wrote:

> 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 :-)

Easy. Make a new composite material,
Kevlar/Kevlar, and put them perpendicular to
each other :)

AMuzi

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Feb 1, 2018, 9:26:51 PM2/1/18
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Kevlar/Aramid excels in tensile strength. Maybe you should
review this:
http://www.instron.us/en-us/our-company/library/test-types/tensile-test

but it's unremarkable in shear.

Emanuel Berg

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Feb 1, 2018, 10:09:56 PM2/1/18
to
AMuzi wrote:

> Kevlar/Aramid excels in tensile strength.
> Maybe you should review this:
> http://www.instron.us/en-us/our-company/library/test-types/tensile-test

OK, seems like a lot to digest but no one said
it was supposed to be easy, right?

> but it's unremarkable in shear.

One better double-check the direction of the
fibers before pulling on the bulletproof
vest :)

BTW I wonder if this is why it is used in
hockey sticks, skis, etc. "Hard and flex at the
same time", remember?

The hockey stick for sure cannot be pulled any
longer than its original 60 inches (~152cm) but
one can budge it on the middle leaning on it
and giving it just a small extra push.
This property in the hockey world is called,
with this instance as an example, "flex 85"
(which is pretty hard, for a strong but
medium-sized player). I'm unsure if this is
just a digit the manufacturers use or if it has
some scientific ground as well WRT
the material.

John B.

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Feb 1, 2018, 10:27:11 PM2/1/18
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On Fri, 02 Feb 2018 03:19:07 +0100, Emanuel Berg <moa...@zoho.com>
wrote:
Given that the New Age thinking seems to be that weight is secondary
in importance to streamlining maybe it is time to return to steel
frames. Aerodynamically designed, of course.

--
Cheers,

John B.

AMuzi

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Feb 2, 2018, 8:32:22 AM2/2/18
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I'm sure Frank could discuss tension and compression in a
beam better but here you go:

http://people.virginia.edu/~pjm8f/engr162/beam/stress_and_strain.htm

avag...@gmail.com

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Feb 2, 2018, 12:31:16 PM2/2/18
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Today carbon fiber.

Unbelievable kayak paddle$

One swing = x 1000 swings =

I would prowl new canoe lots rapping on hulls checking new claims

See CF custom canoe

https://www.google.com/search?q=aramid+cut&prmd=sivn&source=lnms&sa=X&ved=0ahUKEwiQ87Gg4IfZAhVioFkKHeLAABsQ_AUIECgA&biw=360&bih=560&dpr=3#scso=uid_XZ90WtqbC8zR5gK_6ZH4Ag_1:64

Emanuel Berg

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Feb 7, 2018, 7:16:57 PM2/7/18
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Maxxis Detonator 23x622 clinchers have Kevlar
wire. Making the tire more straight/strong
and/or lighter while making the bike
more expensive?

John B.

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Feb 7, 2018, 9:02:28 PM2/7/18
to
On Thu, 08 Feb 2018 01:16:54 +0100, Emanuel Berg <moa...@zoho.com>
wrote:

>Maxxis Detonator 23x622 clinchers have Kevlar
>wire. Making the tire more straight/strong
>and/or lighter while making the bike
>more expensive?

Well, replacing some plain old steel wire with an exotic synthetic
material is very likely to increase prices :-) On the other hand the
synthetic's are about ten gm lighter, if that is important.
--
Cheers,

John B.

Emanuel Berg

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Feb 27, 2018, 6:14:49 PM2/27/18
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I have now played a couple of games with the
"composite" stick (CFRP + Kevlar/aramid).

The weight, including tape, stopped at 490g
compared to my old wood/glass fiber which was
809g. This was certainly noticable in many
positive ways.

But in one way, the old wood stick was better
and that was its comfort! With this, new one,
it felt like every blow to it went straight
thru and into my hands and forearms - really
painful!

I suppose the fibers of wood are less straight,
or more circular (?), or something that makes
them not carry thru vibrations the same way?

Is this something one would notice with carbon
bikes as well, compared to steel frames/forks,
or do the wheels absorb most of it before it
finds its way all the way into the body?

AMuzi

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Feb 27, 2018, 6:34:32 PM2/27/18
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What sort of stick? Like a police baton? Wood works pretty
well to ensure the message is received(personal experience).

Emanuel Berg

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Feb 27, 2018, 8:41:04 PM2/27/18
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AMuzi wrote:

> What sort of stick? Like a police baton?
> Wood works pretty well to ensure the message
> is received(personal experience).

Ha ha, what did you do? Student street rally?

Stick = ice hockey stick. The composite stick
material is what has elevated the game to
a whole new skill level. That, and new methods
with training but yes, to a large extent the
new stick material.

To me, it doesn't really elevate anything, it
is just a nice toy, but the kids make the most
of it for sure...

Duane

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Feb 28, 2018, 8:08:16 AM2/28/18
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Is there any particular reason that you think the parameters for a
hockey stick would be similar to a bike?

One thing noticeable about composite hockey sticks is that they break a
lot more than wooden ones.

Emanuel Berg

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Feb 28, 2018, 11:51:09 AM2/28/18
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Duane wrote:

> Is there any particular reason that you think
> the parameters for a hockey stick would be
> similar to a bike?

Yes, the material.

Duane

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Feb 28, 2018, 12:14:22 PM2/28/18
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On 28/02/2018 11:51 AM, Emanuel Berg wrote:
> Duane wrote:
>
>> Is there any particular reason that you think
>> the parameters for a hockey stick would be
>> similar to a bike?
>
> Yes, the material.
>
Material is not a parameter. A parameter is an operating consideration.

I seldom try to apply 100 lb stress for a slap shot with my bike. At
least not intentionally. But the hockey stick is intended to do this
when loading the stick. I expect when my bike was designed the stress
parameters were different.
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