Need help deciding on an ASTM (or other) Test Standard

Discussion in 'Materials' started by topwatertiger, Aug 15, 2023.

  1. topwatertiger
    Joined: May 2019
    Posts: 7
    Likes: 0, Points: 1
    Location: New Orleans

    topwatertiger Junior Member

    Quick background on my question.

    I am a current Naval Architect/Marine Engineer working for a design and consulting firm. My entire experience up to this point is with large steel vessels. I am in the beginning stages of designing a fishing skiff and am looking to explore composite materials that, to my knowledge, have never been used in the boat building industry before.

    I have experience with ASTM D790 and successfully used it to test two different 3D printed materials in the past.

    I am now looking to find a test standard to find the sectional properties of my proposed sandwich. Without giving everything away I believe the first sandwich I would like to test will consist of:
    Foam Core
    Layer of coating
    Mesh cloth
    Layer of coating
    Layer of coating

    Is anyone familiar with any test standards they can recommend me to look into? I have a few ASTM standards bookmarked but reaching out for opinions from people more familiar with composites than I am.
     
  2. Tops
    Joined: Aug 2021
    Posts: 225
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    Location: Minnesota

    Tops Senior Member

    Are you familiar with Vectorply's software Vectorlam? It has a neat comparison feature.
     
  3. topwatertiger
    Joined: May 2019
    Posts: 7
    Likes: 0, Points: 1
    Location: New Orleans

    topwatertiger Junior Member

    I've never used that before. Thanks for the recommendation. I will play around with it today.
     
  4. topwatertiger
    Joined: May 2019
    Posts: 7
    Likes: 0, Points: 1
    Location: New Orleans

    topwatertiger Junior Member

    Just got done clicking around on there for an hour or so. Really neat tool but not sure that will be able to help me unless I am misunderstanding the full abilities of Vectorlam.

    I am more or less looking for a testing standard to apply to a real model of the proposed sandwich and find out the sectional properties. The sandwich is comprised of a few materials that are tough to find material properties on and I feel the easiest way for me to figure out the properties will be by doing tests.
     

  5. TANSL
    Joined: Sep 2011
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    Location: Spain

    TANSL Senior Member

    Composites have been used in shipbuilding for decades, mainly in fishing vessels of all kinds. There are, therefore, many people who will be able to advise you on the matter. I would advise you four things, to start with:
    • Since you are used to working for large steel ships, you will know how to handle the Regulations of the Classification Societies. They talk about how to calculate the mechanical properties of any laminate, how to find out their design stresses, the loads on them and the admissible values.
    • If you are determined to use a sandwhich panel, you should know that the core must be placed as close as possible to the neutral axis of the cross section of the laminate.
    • If you don't specify the materials you want to use in the core and in the various layers, there will be no way to calculate their mechanical properties. Talking about "mesh" or "coating" means nothing, you have to better define the layers with the specific material that each one has.
    • In general, except in very special cases, it is not necessary to carry out laboratory tests with approved test tubes, etc. so in my opinion you can forget ASTM standards
    Cheer up, you're not dealing with rocket science, lots of people have done it before and it's a fairly mastered technique.
     
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