Easy carbon fibre question
Discussion
Ferg said:A resin reinforced with carbon fibres is carbon fibre. There's no plastic involved.
...a resin reinforced with carbon fibre might well be called Carbon fibre reinforced plastic.....???
john_p said:Composites can be made up of loads of different things. Concrete's a composite. To be a composite the materials that make it up have to be distinctly different.
...and similarly, if something was described as a "composite material" do we assume that it means CF/CFRP or could it be made up of all sorts of other stuff?
fid said:
...a resin reinforced with carbon fibre might well be called Carbon fibre reinforced plastic.....???
A resin reinforced with carbon fibres is carbon fibre. There's no plastic involved.
Sure there is. The "resin". It's just the same as a polymer material reinforced with glass fibres is called "glass fibre" for short but is more pedantically "glass fibre reinforced plastic". In the GF case the plastic is a polyester, similar to what drinks bottles are made of. I think an epoxy is more commonly used with CF, but you can use it with GF as well.
Pigeon said:You've taught me more in 30 seconds than my materials lecturer has in 7 months
Ferg said:
...a resin reinforced with carbon fibre might well be called Carbon fibre reinforced plastic.....???
A resin reinforced with carbon fibres is carbon fibre. There's no plastic involved.
Sure there is. The "resin". It's just the same as a polymer material reinforced with glass fibres is called "glass fibre" for short but is more pedantically "glass fibre reinforced plastic". In the GF case the plastic is a polyester, similar to what drinks bottles are made of. I think an epoxy is more commonly used with CF, but you can use it with GF as well.
A composite material is a substance made from a matrix (normally a resin) and a reinforcement (the fibre in most cases), mechanically separable (in that they don't chemically combine), resulting in properties in excess of the parts.
Carbon fibre, technically, is strands of carbon. These are very strong in tension but can be bent with little effort. Carbon Fibre Reinforced Plastic is carbon fibre reinforcement in a matrix usually of an epoxy or polymer resin (which are types of thermo-set plastic).
In the case of F1, the tub, wings, etc are made from pre-preg carbon fibre which is a "cloth" of carbon fibres impregnated with epoxy resin. This is then cut and draped in place in the mold, laminated with several layers. In places it will also have a core within the laminates of CF (often a honeycomb of aluminium or some other lightweight material). Once all layed up into the mould, it's vacuum bagged and placed in an autoclave where it is baked at temperature under high pressure.
This, however, is not the only way to make a composite part. Pre-preg is not the only way of obtaining the composite material - you can also get dry weave or chopped strand mat for wet layup - the reinforcement is put in place and wetted out with resin. This is cheaper, but more difficult to get the right ratio of resin/reinforcement than buying pre preg.
Additionally, the reinforcement need not be just carbon fibre, but can be aramid (kevlar) which is not as light but has an amount of impact resistance (it's the same stuff used in bullet proof vests, just strands of it) or indeed glass fibre which as you might expect is fibres of glass. As well as a woven mat, glass is also commonly available in chopped strand mat which is randomly combined strands of glass fibre held together with a light bonding agent that is dissolved by the resin when wetted out.
Finally, not all composites need to be autoclaved. Although high temperature, autoclaved composites will be used for structural parts such as chassis, etc. but you can make other parts without it. Obviously fibre glass made with CSM is usually cured at room temperature, other composites, even pre-preg carbon can be obtained with resin that cure at lower temperatures including room temperature.
Blah, blah, blah, I could go on for hours. If anyone wants to know more, feel free to mail me, or better still speak to the National College of Motorsport about their week long composites courses.
One of these days I'll get round to writing an article or three about composites.
Carbon fibre, technically, is strands of carbon. These are very strong in tension but can be bent with little effort. Carbon Fibre Reinforced Plastic is carbon fibre reinforcement in a matrix usually of an epoxy or polymer resin (which are types of thermo-set plastic).
In the case of F1, the tub, wings, etc are made from pre-preg carbon fibre which is a "cloth" of carbon fibres impregnated with epoxy resin. This is then cut and draped in place in the mold, laminated with several layers. In places it will also have a core within the laminates of CF (often a honeycomb of aluminium or some other lightweight material). Once all layed up into the mould, it's vacuum bagged and placed in an autoclave where it is baked at temperature under high pressure.
This, however, is not the only way to make a composite part. Pre-preg is not the only way of obtaining the composite material - you can also get dry weave or chopped strand mat for wet layup - the reinforcement is put in place and wetted out with resin. This is cheaper, but more difficult to get the right ratio of resin/reinforcement than buying pre preg.
Additionally, the reinforcement need not be just carbon fibre, but can be aramid (kevlar) which is not as light but has an amount of impact resistance (it's the same stuff used in bullet proof vests, just strands of it) or indeed glass fibre which as you might expect is fibres of glass. As well as a woven mat, glass is also commonly available in chopped strand mat which is randomly combined strands of glass fibre held together with a light bonding agent that is dissolved by the resin when wetted out.
Finally, not all composites need to be autoclaved. Although high temperature, autoclaved composites will be used for structural parts such as chassis, etc. but you can make other parts without it. Obviously fibre glass made with CSM is usually cured at room temperature, other composites, even pre-preg carbon can be obtained with resin that cure at lower temperatures including room temperature.
Blah, blah, blah, I could go on for hours.
If anyone wants to know more, feel free to mail me, or better still speak to the National College of Motorsport about their week long composites courses. One of these days I'll get round to writing an article or three about composites.
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