Large deformation in rubber sample

lambefr
lambefr New Altair Community Member
edited October 2020 in Community Q&A

I am trying to model a rubber material that has 300%+ elongation capacity.  I don't need to model the rupture mode, just the fact that it can deform elastically and return to its original shape.  I tried with LAW2 and LAW42 but my solid elements (BRICK) just seem to explode when I reach close to 100% elongation.  I tried different ISOLID (1,14,24), but I always get the same result.

 

Any advices welcome, thanks.  Images of model and .rad, .out below.

 

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Answers

  • Simon Križnik
    Simon Križnik Altair Community Member
    edited November 2019

    Hi,

     

     

    I was able to make the law 42 work

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  • Andy_20955
    Andy_20955 New Altair Community Member
    edited November 2019

    Hi,

    Using LAW42 would be recommended since it is a rubber material.

     

    Using Ismstr = 10 is recommended with hyperelastic material laws.  As HyperMan shows, /PROP/SOLID, Isolid=14 with Ismstr = 10 works. 

     

    Or you can use /PROP/SOLID, IHKT = 2 with Isolid = 24 (HEPH) and Ismstr = 10 which runs a little faster and also works. 

     

    We have this statement in the comments of /PROP/SOLID but I realize it is easy to miss.

     

    For foam or rubber materials such as laws 38, 42, 69, 82 and 88, it is recommended to use IHKT = 2 with Isolid = 24 (HEPH) and Ismstr = 10, 12 (Lagrange type total strain).

     

    Thanks,

    Andy

     

  • lambefr
    lambefr New Altair Community Member
    edited November 2019

    Thanks Hyperman and Andy for the edited model and the pointers to changing the PROP parameters.  I had missed the comments.

     

    Thank you for your help.

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