Learning Forum

[bb123.kim]

Hello,

I'm doing a Modal_Analysis in LS-Dyna.

I want to process the Bonded condition as Tied, and other attached surfaces are treated with No-Separation.

It was confirmed that it behaves as desired when applying General Contact. (it seems like no-separation)

However, when applying General Contact, even if there is some gap, Contact is applied and they behave together.

After testing, I found that if it is less than 40% of the element size, it is recognized as Contact.

Is there an option to adjust this tolerance value?

Thanks.

[igandiko]

Any contact in modal analysis will be treated as a tied contact if the surfaces are "sufficiently" close. If there is too much gap between the surfaces, you can increase SAST/SBST parameters (for shells) or SLDTHK parameter (for solids). 

*CONTACT_AUTOMATIC_SINGLE_SURFACE_TIED could be more convenient option since it has "CLOSE" parameter to define "closeness" tolerance.