Automatic-single-surface

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FREIDOUN KAMRANIMEHR

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Mar 3, 2022, 12:08:55 PM3/3/22
to LS-DYNA2

Dear all

How to set Automatic-single-surface contact so that all of below options be activated together:

- surface to surface contact

- edge to surface contact

- edge to edge contact 

James M. Kennedy

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Mar 3, 2022, 5:08:36 PM3/3/22
to FREIDOUN KAMRANIMEHR, LS-DYNA2

Dear Freidoun,

 

For SOFT = 2, the DEPTH parameter controls several additional options for segment based contact.

1. DEPTH = 2 (default; but not recommended). Surface penetrations measured at nodes are checked.

2. DEPTH = 3. Surface penetration is also measured at the edge. This option is more accurate than

DEPTH = 2 and is good for a wide variety of simulations but does not check for edge-to-edge

penetration.

3. DEPTH = 5. Both surface penetrations and edge-to-edge penetrations are checked.

4. DEPTH = 13. The penetration checking is the same as for DEPTH =3, but the code has been tuned

to better conserve energy.

5. DEPTH = 15. Behavior is the same as DEPTH = 5 from versions R4.2 and earlier. This option

enables backward compatibility of results.

6. DEPTH = 23. The penetration checking is similar to DEPTH = 3 but uses different methods to try

to improve robustness.

7. DEPTH = 25 or 35. The penetration checking is similar to DEPTH = 5 but uses different methods

to try to improve robustness.

 

EDGEK - Scale factor for penalty stiffness of edge to edge contact when SOFT = 2 and DEPTH =

5, 15, 25, or 35 (see Remark 4):

EQ.0.0: Use the default penalty stiffness.

GT.0.0: Scale the stiffness by EDGEK.

 

4. EDGEK. When SOFT = 2 and DEPTH = 5, 15, 25, or 35 on Optional Card A, the EDGEK

parameter will scale the contact penalty stiffness when contact is between segment edges if EDGEK >

0.0. This is true for both shell segments and solid element segments. Surface contact stiffness is

unaffected by EDGEK.

 

https://www.dynasupport.com/tutorial/contact-modeling-in-ls-dyna/edge-to-edge-contact

 

Most contact types do not check for edge-to-edge penetrations as the search entails only nodal

penetration through a segment. This may be adequate in many cases; however, in some unique shell

contact conditions, the treatment of edge-to-edge contact becomes very important.

 

https://www.dynasupport.com/howtos/contact/edge-to-edge-contact

 

EDGE-to-EDGE Contact can be treated in LS-DYNA via the following three contact types:

 

*CONTACT_SINGLE_EDGE

*CONTACT_AUTOMATIC_GENERAL

*CONTACT_AUTOMATIC_SINGLE_SURFACE with SOFT=2 and DEPTH=5

 

https://ftp.lstc.com/anonymous/outgoing/support/FAQ_docs/contact.pdf

 

Sincerely,

James M. Kennedy

KBSD2 Inc.

March 3, 2022

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