LFA Carbon Weave Loom (w video)
10-30-2009, 05:56 PM
#21
Registered User
Originally Posted by al4t1gbundy,Oct 30 2009, 02:18 PM
Tan you know it's a criminal sin to say something like that and not post pictures right? 
Wow that video is amazing and I'm getting more and more amazed at what is in the LF-A. The overall car though ...
Wow that video is amazing and I'm getting more and more amazed at what is in the LF-A. The overall car though ...
Tan
10-30-2009, 06:42 PM
#22
looks like something out of a science fiction movie. this just blows my mind.... when someone understands just how complicated a piece of machinery like a jacquard loom is, this takes it to a whole new level.
its like weaving multiple plain weave layers one over the other into a solid 3 dimensional shape without even having a mould. question is.... when most carbon fibre is layered the direction of the fibres is done in opposing directions layer over layer to add strength, a resin is used to hold everything together as one cohesive unit. when something can be woven layer to layer with one continuous carbon filament thread do you even NEED resin at all?
its like weaving multiple plain weave layers one over the other into a solid 3 dimensional shape without even having a mould. question is.... when most carbon fibre is layered the direction of the fibres is done in opposing directions layer over layer to add strength, a resin is used to hold everything together as one cohesive unit. when something can be woven layer to layer with one continuous carbon filament thread do you even NEED resin at all?
10-30-2009, 10:49 PM
#24
Originally Posted by illdiealonlyazn,Oct 30 2009, 03:41 PM
that's pretty intense. but after it gets weaved is there any resin added to it? Or is it baked or something?
they will have to bake the composite (resin + fiber together) under pressure to get the best properties out of it. for epoxy, it's typical to heat it to somewhere around 375F for a period of hours at up to 100psi pressure. some resin systems are cured in stages, i.e. by ramping up to a temperature and then holding for a few hours, then raising the temperature again for a "post-cure." it depends on the resin--this is all how you get the polymer to seal the carbon fibers just right.
and thermoset polyesters can be done without heat, but they are lower performance than epoxy. they're often used with glass fibers. you still have to vacuum bag polyester to get rid of air bubbles while it cures. but generally if someone invests in carbon fiber, they use epoxy or better resin systems instead of polyester. you don't buy an armani suit and wear it with payless shoes--same principle.
10-30-2009, 11:02 PM
#25
Originally Posted by budgy,Oct 30 2009, 08:42 PM
its like weaving multiple plain weave layers one over the other into a solid 3 dimensional shape without even having a mould. question is.... when most carbon fibre is layered the direction of the fibres is done in opposing directions layer over layer to add strength, a resin is used to hold everything together as one cohesive unit. when something can be woven layer to layer with one continuous carbon filament thread do you even NEED resin at all?
Here's more explanation from better source than me, a peer reviewed article:
Interfacial bonding. A bundle of fibers (a) usually will have about 70 to 80% of the average tensile strength determined on a single fibers. With a very strong bond between fiber and matrix (b), the whole composite will fail in a brittle manner when the very weakest fiber in the composite fails. Tensile strength is low. An optimal interfacial strength (c) will produce multiple fractures in each filament, and the tensile strength will equal or even exceed the average fiber tensile strength.
___
Fibers can be made in small diameter with desirable microstructures, such that very high strength can be obtained. High loads can be carried by using a plurality of these high-strength fibers. Damage tolerance is also achieved, as the loss of a few fibers does not decrease the overall load-bearing capability much. However, if there is no coupling among a bundle of parallel fibers, fiber fractures accumulate with increasing load until the remaining fibers fail ("bundle strength") (Fig.). There are two problems: (1) no load is carried by a broken or discontinuous fiber, and (2) fibers buckle at very low loads in compression because of their small diameter. Man learned many centuries ago that twisting the continuous fiber bundle into a yarn provides a frictional force among the fibers that also allows discontinuous fibers to be used. Multiple breaks in a single fiber could even be generated in a yarn during loading. However, improving the compressive strength requires better fiber stabilization than coupling by friction. The problem is that in a strongly coupled system, failure of the whole structure occurs when the first fiber fails--a very low strength (Fig. 3b.). Noncatastrophic failure requires that the bond strength between the fiber and matrix be sufficiently low that when the fiber fractures, the fiber debonds from the matrix to arrest crack propagation by blunting (Fig. 3c). Damage tolerance is provided by the redundancy in load-carrying members. Localized impact may fracture a few fibers, but the load carried by the fractured fibers will be transferred through the matrix to the remaining fibers.
10-30-2009, 11:42 PM
#26
Registered User
Originally Posted by Dreaming_S2k,Oct 30 2009, 12:20 PM
That is amazing.
On a funny note, all the haters that are posting comments at the bottom of that page are crazy. It's like no matter how amazing something is, someone's gotta find something wrong with it
On a funny note, all the haters that are posting comments at the bottom of that page are crazy. It's like no matter how amazing something is, someone's gotta find something wrong with it
10-31-2009, 09:18 AM
#27
Originally Posted by ace123,Oct 30 2009, 11:02 PM
Yes, you need resin! Carbon fibers are very brittle and don't stand any compression. If you just have a bunch of fibers together and pull on them, only a few will be tightly pulled, and those few will carry the load and break before the others load up well.
Here's more explanation from better source than me, a peer reviewed article:
Interfacial bonding. A bundle of fibers (a) usually will have about 70 to 80% of the average tensile strength determined on a single fibers. With a very strong bond between fiber and matrix (b), the whole composite will fail in a brittle manner when the very weakest fiber in the composite fails. Tensile strength is low. An optimal interfacial strength (c) will produce multiple fractures in each filament, and the tensile strength will equal or even exceed the average fiber tensile strength.
___
Fibers can be made in small diameter with desirable microstructures, such that very high strength can be obtained. High loads can be carried by using a plurality of these high-strength fibers. Damage tolerance is also achieved, as the loss of a few fibers does not decrease the overall load-bearing capability much. However, if there is no coupling among a bundle of parallel fibers, fiber fractures accumulate with increasing load until the remaining fibers fail ("bundle strength") (Fig.). There are two problems: (1) no load is carried by a broken or discontinuous fiber, and (2) fibers buckle at very low loads in compression because of their small diameter. Man learned many centuries ago that twisting the continuous fiber bundle into a yarn provides a frictional force among the fibers that also allows discontinuous fibers to be used. Multiple breaks in a single fiber could even be generated in a yarn during loading. However, improving the compressive strength requires better fiber stabilization than coupling by friction. The problem is that in a strongly coupled system, failure of the whole structure occurs when the first fiber fails--a very low strength (Fig. 3b.). Noncatastrophic failure requires that the bond strength between the fiber and matrix be sufficiently low that when the fiber fractures, the fiber debonds from the matrix to arrest crack propagation by blunting (Fig. 3c). Damage tolerance is provided by the redundancy in load-carrying members. Localized impact may fracture a few fibers, but the load carried by the fractured fibers will be transferred through the matrix to the remaining fibers.
Here's more explanation from better source than me, a peer reviewed article:
Interfacial bonding. A bundle of fibers (a) usually will have about 70 to 80% of the average tensile strength determined on a single fibers. With a very strong bond between fiber and matrix (b), the whole composite will fail in a brittle manner when the very weakest fiber in the composite fails. Tensile strength is low. An optimal interfacial strength (c) will produce multiple fractures in each filament, and the tensile strength will equal or even exceed the average fiber tensile strength.
___
Fibers can be made in small diameter with desirable microstructures, such that very high strength can be obtained. High loads can be carried by using a plurality of these high-strength fibers. Damage tolerance is also achieved, as the loss of a few fibers does not decrease the overall load-bearing capability much. However, if there is no coupling among a bundle of parallel fibers, fiber fractures accumulate with increasing load until the remaining fibers fail ("bundle strength") (Fig.). There are two problems: (1) no load is carried by a broken or discontinuous fiber, and (2) fibers buckle at very low loads in compression because of their small diameter. Man learned many centuries ago that twisting the continuous fiber bundle into a yarn provides a frictional force among the fibers that also allows discontinuous fibers to be used. Multiple breaks in a single fiber could even be generated in a yarn during loading. However, improving the compressive strength requires better fiber stabilization than coupling by friction. The problem is that in a strongly coupled system, failure of the whole structure occurs when the first fiber fails--a very low strength (Fig. 3b.). Noncatastrophic failure requires that the bond strength between the fiber and matrix be sufficiently low that when the fiber fractures, the fiber debonds from the matrix to arrest crack propagation by blunting (Fig. 3c). Damage tolerance is provided by the redundancy in load-carrying members. Localized impact may fracture a few fibers, but the load carried by the fractured fibers will be transferred through the matrix to the remaining fibers.
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