Optistruct - large contact forces

Andy@LamteqSolutions

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

I've added some images....

 

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

Mario_21478

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