carbon fiber nanocomposites

Discussion in 'Boat Design' started by spidennis, Jul 20, 2012.

  1. spidennis
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    spidennis Chief Sawdust Sweeper

    1 person likes this.
  2. sottorf
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    sottorf member

    there are a number of other companies offering nano-modifeid composite materials. For example check out www.amroy.fi

    They also have a good "green" epoxy on the market.
     
  3. noli
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    noli Junior Member

    .

    Does anyone know how the builders have gotten the nano composites to work in a marine layup schedule?

    The last i heard is that we can only build nano strands up to centimeters long and thus not realistic yet for marine use.

    What have these boat builders achieved with nano technology, I'm curious

    .
     
  4. sottorf
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    sottorf member

    The nano strands, normally carbon nano-tubes (CNT), are dispersed into the resin. The resin is then used as any other resin used for boatbuilding. THe difference here is the resin is itself a composite material with the following advantages:
    - small increase in ultimate strength
    - big increase in fatigue strength
    - big increase in abrasion resistance
    - better UV resistance (less yellowing with sunlight)

    The challenge with these resins is the dispersion of the CNT into the resin. The CNT strands tend to clump together so you need very special techniques to disperse them and ensure they remain dispersed. I am not familiar with howZyvex does this but Amroy have a patented acoustic process coupled with some chemical treatments to achieve this.
     
  5. noli
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    noli Junior Member

    .

    Thanks Sotto,

    Def great to know.

    One of the aims of CNT technology is that the hulls can be built to be much lighter. This 57 footer weighs just 17,900 pounds. How does CNT able to do this?



    Photo credit: www.gizmag.com


    [​IMG]


    .
     
  6. sottorf
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    sottorf member

    The light weight indicates the boat probably makes use of a fully carbon fibre structure together with the a nano-modifed epoxy resin and probably produced via vacum infusion. Most likely the structure was designed using extensive finite element analysis rather than relying purely on class rules.

    Attached is a paper which briefly covers the advantages of building boats in carbon. This particular vessel was built by Brodrene AA www.braa.no in Norway. They are one of best in building large structures in carbon fibre using infusion. I know they are now looking into using CNT modified resins to further improve their vessels.
     
  7. spidennis
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    spidennis Chief Sawdust Sweeper

    I wonder just how these materials could affect racing canoes and kayaks?

    or Adirondack Pack Canoes? When you have to portage everything on your back it's nice to have a very light weight boat. Presently I'm toting a Placid Boatworks Rapidfire, 15' @25 lbs that can use either a double or single paddle.
    http://placidboats.com/
    I also race this boat in the three day 90 mile Adirondack Canoe Classic


    I also want a boat for the Texas Water Safari, a 260 mile non stop down river race. It has to be light, fast, and oh so durable.

    http://www.texaswatersafari.org/

    .... and then there's the 1200 mile Ultimate Florida Challenge and 300 mile Everglades Challenge where I'm designing an adventure racing proa.

    http://watertribe.org/

    so you can see that looking into these newer building technologies could be useful for me! Hopefully it won't be so high tech that it can't be built in a garage?

    [​IMG]
     
  8. SamSam
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    SamSam Senior Member

    .

    http://www.nanion.cn/images/stories/papers/NanoLetters_Cytotoxicity.pdf

    The obsession with lightness may have consequences.

    I had to take an asbestos awareness course and apparently what makes asbestos useful and at the same time so bad, is that it's composed of fiberous bundles that can continue to break down in size to a molecular level. At that level they easily penetrate single cells in the body and disrupt that cell's modus operandi which leads to cancer.

    Think of #3 when pouring out a measure of carbon nano resin filler or sanding a CN laminate. As far as CN reaching the lungs, I wonder what sort of air-filter mask works on a nano molecular level?

    Hmmmm. I just posted the first link I came to in my search, here's the title of the second link from Scientific American...

    http://www.scientificamerican.com/article.cfm?id=carbon-nanotube-danger

    Of course, industry would not foist an unsafe material unto the general public *cough*cigarettes*cough* so nano technology must be safe, as they are now using it to make color shifting clothing.

    Whatever you do, do not fetter industry or the market with restrictions, it is unCapitalistic and smacks of Socialism.
     
  9. upchurchmr
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    upchurchmr Senior Member

    Gentlemen,

    EPA has put severe restrictions on the handling of carbon nanotubes in the aerospace industry. One of our suppliers put in a very expensive Clean Room just to be able to drill the finished parts.
    Part of the problem is there is no actual knowledge of the effect of carbon nanotubes on humans, but the shape and size of the tubes is approximately the same as asbestos - so everyone is running scared.
    BTW, the diameter of the carbon nanotubes are ~1000th the dia of a typical carbon fiber, and the length is only 100 to 1000 times the diameter. so no long nanotubes. It is the long fibers in carbon that provides the strength, so the nanotubes are just reinforcement of the resin, but not the major strength provider. Additionally it is difficult to combine much nano (by weight) into the resin, so any effects are limited.
    Don't believe all the hype!
    But, people are still developing the material and applications - maybe soon. But if you think carbon is expensive - just wait.

    There are other "nano" materials besides carbon nanotubes.

    Spidennis,

    If you want light weight and high stiffness, check out Boron fibers. Old technology, but still valid. Not sure you can still get them in a commercial form for boat building.
     
  10. sottorf
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    sottorf member

    the effects of adding CNT into resin are very real. There is enough literature around documenting the improved mechanical properties.

    Regarding Kayaks, there is a company called Red7 in South Africa who is building kayaks using the Amory products (I think).

    Yes there are many other nano-additives out there. THe most recent developments are nano-capsules which contain a variety of chemical compounds. These can serve to slef-repair cracks, provide anti-fouling etc. Lots of interesting things coming in this field.
     
  11. Red Dwarf
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    Red Dwarf Senior Member

    The improvements are real but not that important in real life. The improvements are easy to document in a lab setting. But the problem is we are talking about boats not F1 cars or satellite structures. In a state of the art application, where no cost is spared for a small improvement, the structure has already been studied and optimized so the small benefit the nanotubes provide is real.

    In a boat that is made of glass and foam? No way you should waste time with nanotubes. Optimize the structure and use better materials. Even if the boat is already carbon there are lots of carbon grades available and far more benefit is gained by going to the better fibers. The high end fibers are over 2-3 times as strong and stiff as the run of the mill carbon fibers 99% of people use. Of course if you have already exhausted all these optimization levels (and spent millions) then you can look for that last few percentage offered by the nanotubes.
     
  12. noli
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    noli Junior Member

    .

    R.D. that's a good point and one that I totally should follow.

    Case in point I am associated with a hi-perf cat builder on Long Island NY.

    We'd like to try carbon, epoxy, kevlar in building our 115+ MPH cats.

    We currently vacuum bag end-grain balsa + hi-density foam + vinyl esther resins.

    On our hi-perf hulls, what would be a good layup schedule incorporating the following into our core sandwich:

    1. carbon fibre
    2. epoxy
    3. kevlar

    The more detailed the better. Thanks in advance.

    .
     
  13. sottorf
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    sottorf member

    I dont agree with that. There is good benifit to be gained out of using CNT epoxies. When you build boats ultimate strength of the fibres is rarely the main consideration - fatigue strength is, and CNT epoxies provide significant gains there in the weakest link which is the resin matrix and not the fibres.

    Also CNT modified epoxies provide much better abrasion/scratch resistance. Something very important to most yacht owners trying to keep their boat looking good!

    If CNT epoxies did not provide benefit why would one of Europe's top yacht builders, Baltic yachts, www.balticyachts.fi use such resin?
     

  14. Ad Hoc
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    Ad Hoc Naval Architect

    I did a similar course many years ago.

    It is not so much the size per se, (they categorise in to 3 types if memory serves), but it is the ability of the body to either remove the fibre or, of the fibre remains, causes no long term problems and is either broken down, remains inert or slowly passes through. Technically, or rather medically, is called having a low pulmonary biopersistence. All fibres are now controlled via the EU directive on such matters: 67/548/EEC. A list of approved materials is given here:
    http://www.greencouncil.org/doc/ResourcesCentre/annex1.pdf

    I simply have no idea what socialism has to do with the body’s ability to fight or pass fibre through the body :confused::confused::!:

    It’s called "high-tech" marketing and probably coupled with design gaffs where no other material could do the job to keep the project going and not becoming a heavy behemoth!

    No different to the new aluminium “wonder alloys” that came out in the mid to late 90s: 5383 and 5059. Just because they offer “better” characteristics, doesn’t mean they will be wildly or automatically adopted. Other aspects of a design often dominate over such simple choices.
     
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