Contact Convergence

S_C_A
S_C_A Altair Community Member
edited October 2020 in Community Q&A

Hello All,

 

I am relatively new to use contacts and running non-linear analysis in Optistruct. I am facing convergence issues in my model with static friction contact.

 

I have used NLPARM + Non Linear Quasi Static analysis to run the simulation with friction contacts.

 

In the picture you will see that the body in pink is tetra mesh with aluminium and the yellow component is penta mesh with titanium. Load is applied on the titanium and contacts are defined between.

 

I haven't used any PCONT cards here as I have not much experience with it.

 

Here the yellow component being the harder component and the component with the load has been set as the master. Both the sets 'Pink' & 'Yellow' here are element sets

 

The Y distance between the yellow and the pink component is 5.004e-03mm.

 

 

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Answers

  • Rahul Rajan_21763
    Rahul Rajan_21763 New Altair Community Member
    edited July 2019

    Could you please share the .out file of the run ?

  • S_C_A
    S_C_A Altair Community Member
    edited July 2019

    Yes sure.

    PFA

    Unable to find an attachment - read this blog

  • FaroukM
    FaroukM Altair Community Member
    edited July 2019

    Hey ! 

     

    Try to add S2S DISCRET and add Contact Stab. 

     

    Verify the normal of slave and master surface ... 

     

    Could you please share your fem file, if it's not confidential ? 

     

    Cheers ! 

  • S_C_A
    S_C_A Altair Community Member
    edited August 2019

    Thanks for the reply Mr. Farouk, unfortunately I won't be able to share the model.

     

    However I played around a bit with the S2S option + Adjust options and now I am able to converge the model. Yet I am not very sure if that is the right method. I need to do some further studies using sub modelling to understanding the real meaning of it.

  • Rahul Rajan_21763
    Rahul Rajan_21763 New Altair Community Member
    edited August 2019

    Do you see any waring or info in the converged model files?

  • S_C_A
    S_C_A Altair Community Member
    edited August 2019

    I had run a few iterations on my model using different contact options

     

    1. friction 0.3 | Auto Adjust | clearance 0.001| discrete S2S ==> this had no warnings on the way to convergence

    2. friction 0.3 | Discrete S2S ==> this took 2 to 3 sub steps (load breaking down) to converge

    3. friction 0.3 | clearance 0.001| discrete S2S ==> this had no warnings on the way to convergence

    4. friction 0.3 | Auto Adjust| discrete S2S ==> this had no warnings on the way to convergence with the minimal of iterations

     

    as mentioned above I am yet to find out clearly the physical meaning of the above options and the reason for the convergence due to the additional options

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