optistruct gap close_st value is not converge

tonychen
tonychen New Altair Community Member
edited December 2022 in Community Q&A

hi everyone,

i face a problem, when i solve a non-linear transient,it can't converge

should i how to check my modal?

 

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Best Answer

  • Adriano A. Koga
    Adriano A. Koga
    Altair Employee
    edited December 2022 Answer ✓

    Hi,

     

    checking a NL model might be a little bit tricky as many things can happen there.

    First I would recommend you to take some time and go through your .out (and _nl.out) file as it shows you generally what is going on.

    Additionally, try running your model with the card PARAM,NLMON,DISP as it writes a separate .H3D file with the displacements of your NL iterations, so that you could open this file in HyperView and look what is going on, and have more clues on what is going on.

    Probably some contact is not doing well.

    Another tip is to include contacts step-by-step. For example, start with all contacts as FREEZE/TIE. Run your model. Then if everything is ok, try changing some of these to full NL, and run again, until you have all your contacts fully NL, as needed.

    Also, try using contact stabilization to assist initial contact status. PARAM,EXPERTNL,CNTSTB or a load collector CNTSTB called into you loadstep.

     

    The below post shows some aspects to take care of.

    https://community.altair.com/community?id=community_blog&sys_id=538764ab1b3790d4a5f742eddc4bcba4

Answers

  • Adriano A. Koga
    Adriano A. Koga
    Altair Employee
    edited December 2022 Answer ✓

    Hi,

     

    checking a NL model might be a little bit tricky as many things can happen there.

    First I would recommend you to take some time and go through your .out (and _nl.out) file as it shows you generally what is going on.

    Additionally, try running your model with the card PARAM,NLMON,DISP as it writes a separate .H3D file with the displacements of your NL iterations, so that you could open this file in HyperView and look what is going on, and have more clues on what is going on.

    Probably some contact is not doing well.

    Another tip is to include contacts step-by-step. For example, start with all contacts as FREEZE/TIE. Run your model. Then if everything is ok, try changing some of these to full NL, and run again, until you have all your contacts fully NL, as needed.

    Also, try using contact stabilization to assist initial contact status. PARAM,EXPERTNL,CNTSTB or a load collector CNTSTB called into you loadstep.

     

    The below post shows some aspects to take care of.

    https://community.altair.com/community?id=community_blog&sys_id=538764ab1b3790d4a5f742eddc4bcba4

  • tonychen
    tonychen New Altair Community Member
    edited December 2022
    Adriano A. Koga_21884 said:

    Hi,

     

    checking a NL model might be a little bit tricky as many things can happen there.

    First I would recommend you to take some time and go through your .out (and _nl.out) file as it shows you generally what is going on.

    Additionally, try running your model with the card PARAM,NLMON,DISP as it writes a separate .H3D file with the displacements of your NL iterations, so that you could open this file in HyperView and look what is going on, and have more clues on what is going on.

    Probably some contact is not doing well.

    Another tip is to include contacts step-by-step. For example, start with all contacts as FREEZE/TIE. Run your model. Then if everything is ok, try changing some of these to full NL, and run again, until you have all your contacts fully NL, as needed.

    Also, try using contact stabilization to assist initial contact status. PARAM,EXPERTNL,CNTSTB or a load collector CNTSTB called into you loadstep.

     

    The below post shows some aspects to take care of.

    https://community.altair.com/community?id=community_blog&sys_id=538764ab1b3790d4a5f742eddc4bcba4

    i love your and your answer,exactly!!

    thanks

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