Adhesive connections

Altair Forum User
Altair Forum User
Altair Employee
edited November 2020 in Community Q&A

Hi,

 

I'm currently experimenting with different connection types to simulate adhesive bonds. I want to find the best way to analyze large scale bonded shell models. So far I've been examined different options for area connectors, such as: shell gap, mid thickness, etc.

 

The problem I have is that when I increase the adhesive thickness I get some incorrect results. Up to 3 mm in thickness, all the results seem acceptable, but with 5 mm and 10 mm thickness it looks false. More details:

  • I use Optistruct, and running a Linear Static analysis
  • The adhesive layer seems too rigid, although I use the real parameters of the glue. It seems like the glue is trying to maintain its position (perpendicular) to the sheet, and isn't deforming enough.

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My question is: is there any rule regarding the range that a connector type can be used in? (For example: area connector in shell gap mode is good for adhesive layers in the 1-3 mm range.) Or in other words, is there a limit thickness where adhesive area connectors can't be used anymore?

 

I attached the model I was using.

 

Also, what modelling method can you suggest to analyse large scale shell models with adhesives (for example: a boat)?

 

Thanks,
Sebo

 

Unable to find an attachment - read this blog

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Answers

  • Sanjay Nainani_20973
    Sanjay Nainani_20973 New Altair Community Member
    edited April 2018

    Hello,

     

    There is no such rule regarding the range of the connector.

     

    Please refer this detailed document on connectors.

     

    Thankyou

    Unable to find an attachment - read this blog

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2018

    Hi there!

     

    I'm also interested in such case of connectors. I've looked into the connectors training what Sanjay attached and I think the best way to model adhesive bonding is the adhesive connectors with mid thickness option. In that way the real adhesive thickness is used unlike the shell gap option.
    If you use area connector thickness within 5 and 10 mm your results could be very confusing, and I think it is not so realistic. It would be useful if you have any measurements data to validate your model, without that I would not use such unrealistic thickness.


    'The maintaining perpendicular constraint' is interested. I do not know the proper answer.
    Sanjay, what do you think, why is this perpendicular? In this case could be a geometry nonlinear problem? I think the displacement is too large for Linear Static analysis and for small displacement theory.

     

    Sorry that I couldn't help, but I wanted to comment here, because I'm interested in this adhesive bonding problem.

     

    Thanks for the question and the answer guys!

     

    Best wishes,

    Tüki
     

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