Honeycomb vs corecell noise damping

Discussion in 'Materials' started by sigurd, Jun 29, 2011.

  1. sigurd
    Joined: Jun 2004
    Posts: 827
    Likes: 8, Points: 18, Legacy Rep: 65
    Location: norway

    sigurd Pompuous Pangolin

    Anyone have an opinion of which transmits least water noise? Plascore/Nidacore polypropylene core is advertized as damping noise but I am considering aramid/nomex honeycomb.
    Also looking for tips wrt wet layup vacuum bagging the aramid cores.
     
  2. DGreenwood
    Joined: Aug 2004
    Posts: 718
    Likes: 38, Points: 28, Legacy Rep: 507
    Location: New York

    DGreenwood Senior Member

    Here is a tip on wet layup vacuum bagging aramid cores...don't even try it. I have done it with cured skins and aircraft ply bonded to it but even that is pretty shaky. Controlling the glue line between the fiber of your choice and the honey comb is critical. It is possible to assure a good interface there, with enough epoxy, but then you begin to get heavy and waste all the money you spent on the aramid.
    Nomex honeycomb is best when teamed with prepreg, an engineer, a skilled composites tech, and a well controlled oven. And then, if you want to be really sure an autoclave is much better insurance for this type of construction.
     
  3. Petros
    Joined: Oct 2007
    Posts: 2,936
    Likes: 139, Points: 63, Legacy Rep: 1593
    Location: Arlington, WA-USA

    Petros Senior Member

    For sound damping the more dense the material, the less sound transmission. A concrete hull for example with block most of the noise, while a fabric skin from a skin-on-frame will block almost none of it.

    Building a hull heavy just to dampen noise is not advisable, but that is way sound is transmitted, through the air, and the less dence the material means more entrained air, that allows noise transmission. Other tips that might help a little to make the panels well braced so there is no "oil canning" of large panels. Make the whole hull stiff to lessen transmitted noise though out the hull.

    Good luck.
     
  4. Ad Hoc
    Joined: Oct 2008
    Posts: 6,196
    Likes: 414, Points: 83, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    Like everything related to noise, it is frequency dependent. You need to establish what are your dominant frequencies first, to see if the selected material can even address the range you're investigating. Otherwise you could waste a lot of time and money buying a product that is great in one application, but of no use in yours.
     
  5. Herman
    Joined: Oct 2004
    Posts: 1,617
    Likes: 89, Points: 48, Legacy Rep: 1240
    Location: The Netherlands

    Herman Senior Member

    From experience: noise in the living area of the boat: Nomex will not damp anything, Nidacore a lot. However, I do not recommend Nida for long term boat hulls.

    Core-Cell would be a viable option, or Airex R63
     
    1 person likes this.
  6. sigurd
    Joined: Jun 2004
    Posts: 827
    Likes: 8, Points: 18, Legacy Rep: 65
    Location: norway

    sigurd Pompuous Pangolin

    Ok, so corecell is better than Nomex in that regard - thanks for letting me know.
     
  7. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 473, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    It also depends on the noise, vibrational or airborne.
     
  8. Herman
    Joined: Oct 2004
    Posts: 1,617
    Likes: 89, Points: 48, Legacy Rep: 1240
    Location: The Netherlands

    Herman Senior Member

    water noise he asked for.

    Nomex boats make that nasty "bang" each time it hits a wave. More flexible boats are much less noisy in that respect.
     

  9. sigurd
    Joined: Jun 2004
    Posts: 827
    Likes: 8, Points: 18, Legacy Rep: 65
    Location: norway

    sigurd Pompuous Pangolin

    Hm, do these statements contradict each other? Perhaps it has something to do with the difference between noise generation and noise transmission?

    Anyway, great help.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.