Optistruct - large contact forces

Andy@LamteqSolutions
Andy@LamteqSolutions Altair Community Member
edited October 2020 in Community Q&A

Hi All,

 

I seem to have a recurring issue and it doesn't seem to make much difference if I use S2S or N2S. 

 

I have a number of very similar models, all set up the same way and I would only expect a mild difference in stress distribution and contact. What I get is with some of the loadcases I have an extremely high contact force. Now I've encountered this before and have needed to switch to gaps but this time I really do need the contact forces exported. 

 

Here are some notes.....

NLPARA = NINC 10

PARAM = CNTSTB

Contact card  = Adjust = auto, type = slide, MORIENT = Norm.

In general, slave contact surface is smaller mesh size. 

<?xml version="1.0" encoding="UTF-8"?>CONTACT_ISSUE_STRESS.thumb.jpg.00abbe5f6539bc261a86b13b6ca35d74.jpg<?xml version="1.0" encoding="UTF-8"?>CONTACT_ISSUE_FORCE.thumb.jpg.4c3ed111a17f2a21970197f3781640f3.jpg

I've added some images....

 

<?xml version="1.0" encoding="UTF-8"?>problem.JPG

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Answers

  • Mario_21478
    Mario_21478 Altair Community Member
    edited December 2018

    Hello Andy,

     

    In your case, I would recommend the following for the CONTACT card:

     

    TYPE=SLIDE

    MORIENT=OPENGAP

    SRCHDIS= check your distance, small value

    ADJUST=NO (be carefully with AUTO, I would not take it!!)

    CLEARANCE=0 (if it is a closed contact at the beginning)

    DISCRETE=S2S (contact is smoother, better in general)

     

    Try the model without friction first, if it works fine you can add friction.

     

    Best Regards,

    Mario

     

     

  • Andy@LamteqSolutions
    Andy@LamteqSolutions Altair Community Member
    edited December 2018

    Cheers Mario,

     

    Will give it a go and let you know. 

     

    Kindest regards

    Andy

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