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aramid fiber
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 |
#2
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aramid fiber
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 |
#3
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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. |
#4
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aramid fiber
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 -- underground experts united http://user.it.uu.se/~embe8573 |
#5
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aramid fiber
On 2/1/2018 8:19 PM, Emanuel Berg wrote:
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 Kevlar/Aramid excels in tensile strength. Maybe you should review this: http://www.instron.us/en-us/our-comp...s/tensile-test but it's unremarkable in shear. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#6
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aramid fiber
AMuzi wrote:
Kevlar/Aramid excels in tensile strength. Maybe you should review this: http://www.instron.us/en-us/our-comp...s/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. -- underground experts united http://user.it.uu.se/~embe8573 |
#7
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aramid fiber
On 2/1/2018 9:09 PM, Emanuel Berg wrote:
AMuzi wrote: Kevlar/Aramid excels in tensile strength. Maybe you should review this: http://www.instron.us/en-us/our-comp...s/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. I'm sure Frank could discuss tension and compression in a beam better but here you go: http://people.virginia.edu/~pjm8f/en...and_strain.htm -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#8
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aramid fiber
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? -- underground experts united http://user.it.uu.se/~embe8573 |
#9
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aramid fiber
On 2/27/2018 5:14 PM, Emanuel Berg wrote:
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? What sort of stick? Like a police baton? Wood works pretty well to ensure the message is received(personal experience). -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#10
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aramid fiber
On 27/02/2018 6:14 PM, Emanuel Berg wrote:
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? 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. |
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