German Lloyd's Ply orientation recomendation

Discussion in 'Class Societies' started by Roni, May 6, 2021.

  1. Roni
    Joined: May 2020
    Posts: 30
    Likes: 0, Points: 6
    Location: Brazil

    Roni Junior Member

    In GLs 2012 HSC (High Speed Craft) rule there are the following recommendations in section C3.8.9.2:

    A laminate should consist of plies aligned in at
    least 4 distinct directions (e.g. 0°, +/-45°, 90°),
    with not less than 10 % in each direction. Ply angles should be aligned appropriately for major
    load direction(s). Excemptions are the following
    components/items:
    - mainly in-plane shear loaded webs of girders,
    stiffeners, frames
    - local tape reinforcements​

    In my very limited experience I've mostly seen 0/90 laminates used recreational boats. Is there any significant diference in structural behavior between 0/90 and a -45/0/45/90 laminate in these cases?
     
  2. Alik
    Joined: Jul 2003
    Posts: 2,966
    Likes: 275, Points: 93, Legacy Rep: 1306
    Location: Thailand

    Alik Senior Member

    We did many designs to these rules, and we used 0/90, too. Just ignore this recommendation... Direction 45/-45 is good for shear loads only.
     
  3. Roni
    Joined: May 2020
    Posts: 30
    Likes: 0, Points: 6
    Location: Brazil

    Roni Junior Member

    Thanks Alik. At least form the models used in the rules to calculate stress and strains the 45/-45 material is useful for shear loads, as you said
     
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