Solving stud Pretension in Optistruct solver

Vidyaprakash G S
Vidyaprakash G S Altair Community Member
edited July 2021 in Community Q&A

We have solving error in stud pretension in the assembly.

M14 stud with both side washer and nut being used to assembly the 1ton wt assembly.

While defining stud pretension force we got convergent error.

In briefing our geometry

Hollow cylinder assy of two halves each weighing 500kg approx.

Stud vs nut freeze contact remaining all frictional contact defined.

Could any body help to debug will be more useful.

 

 

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Answers

  • Adriano A. Koga
    Adriano A. Koga
    Altair Employee
    edited July 2021

    hi, can you share the .out file?

     

  • Vidyaprakash G S
    Vidyaprakash G S Altair Community Member
    edited July 2021

    Pl.find the out file attached

  • Adriano A. Koga
    Adriano A. Koga
    Altair Employee
    edited July 2021
    Vidyaprakash G S said:

    Pl.find the out file attached

    From the .out file, there are some suggestions. I'd try EXPERTNL,CNTSTB

     Suggestions:
     * Friction or STICK can cause more difficult nonlinear convergence - if feasible
       try frictionless gap/contact.
       Or try stabilized version of expert system: PARAM,EXPERTNL,CNTSTB.
     * This problem has gap elements with friction or stick condition. For more
       intuitive results and often better convergence, set GAPOFFS on GAPPRM card
       to AUTO. (This may violate rigid body balance, especially for unsupported
       structures.) * This problem has nonlinear materials and the number of load increments is small.
       Increasing NINC may help achieve convergence.

    Also reading this might give you some extra tips:

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

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