FRP bonded connection calculations

Discussion in 'Boat Design' started by boats_designer_fr, Jan 31, 2019.

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  1. boats_designer_fr
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    boats_designer_fr New Member

    Hello, I need some help on the topic above. How can I calculate the bonded composite connection of the type as on the picture?
     

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  2. Ad Hoc
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    Ad Hoc Naval Architect

    Hi welcome to the forum,

    Firstly you need to identify the materials you have selected.
    And either via their sales literature, obtain the technical data of the material properties, as a theoretical value, or, much better, build a small sample piece and test it.
     
  3. TANSL
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    TANSL Senior Member

    I think that placing metal plates in a composite structure is not recommended and probably is not correct. It is my opinion.
    In ISO 12215-5, Annex H, you will see a method to calculate the union of reinforcements, or bulkheads, to the hull.
     
  4. Alik
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    Alik Senior Member

    The strength of this detail will greatly depend on manufacturing, namely on surface preparation. I would re-design this detail, fiberglass is not best for such peel-off loads.

    PS It might be foam under this detail to break first...
     
  5. Ad Hoc
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    Ad Hoc Naval Architect

    It is a common feature where high bearing stresses dominate and/or more localised strength is required.
     
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  6. gonzo
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    gonzo Senior Member

    The failure is most likely to be at the core. I assume this is a foam or other low density material.
     
  7. TANSL
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    TANSL Senior Member

    As I understand the picture, this solution is not correct. But I can be misinterpreting the problem.
     
  8. Ad Hoc
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    Ad Hoc Naval Architect

    Based on what evidence?
     
  9. gonzo
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    gonzo Senior Member

    In the evidence of most boats built in the world. However, I qualified my comment by indicating it was an assumption.
     
  10. Ad Hoc
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    Ad Hoc Naval Architect

    Solution to what?

    The question is this:

    So - wanting to know how to calculate the connection is not a correct 'solution'?
     
    Last edited: Feb 1, 2019
  11. Ad Hoc
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    Ad Hoc Naval Architect

    So..the image above....is 'most boats built'...or is it 'something' different than such?

    One can only discuss what is presented, not a pure non-sequitur, that is illogical and not based upon engineering facts.
     
    Last edited: Feb 1, 2019
  12. TANSL
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    TANSL Senior Member

    You do not seem very inspired today. Solution to the union of two pieces of a structure.:p
     
  13. Ad Hoc
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    Ad Hoc Naval Architect

    The OP is NOT asking for a solution. The OP is asking how to calculate its strength.
    Chalk and cheese....again!
     
  14. TANSL
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    TANSL Senior Member

    I know exactly what the OP has asked. But the first thing one should say is that that constructive solution (to join two pieces subject to certain loads, as indicated in the diagram) is not correct and therefore, answer to, as you say, "how to calculate its strength", it does not make any sense. Before calculating anything, it is necessary to give constructive solutions adapted to each problem. I did not expect to have to explain these things to you, I am disappointed, really. :(
    But, please, forget about me and answer the OP since you, apparently, have correctly understood what the OP asks.
    Blah, blah, blah, .... again!
     

  15. Ad Hoc
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    Ad Hoc Naval Architect

    Please show where the OP is asking for an opinion whether the method of joining is correct or not...??
    The rest is noise, until the Q at hand is answered.

    You are not even aware of using metal inserts into composite structures....thus how can you even comment on such as being 'correct' or not.
    If you do not understand the purpose/intent, as you don't as non state thus far, you will go around your usual circular loop of nonsense.
     
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