Learning Forum

[Marco Pedata]

Hello community,

this is my first time trying to set up a Ls-Dyna Restart simulation. I tried different methods but each seem to come with their own difficulties.
I would greatly appreciate solution approaches.

First Option: Export dynain file and import via external model into new Ls-Dyna system
Advantages: Import deformed mesh and initial stresses.
Issues: Weird artifacts - perhaps due to initial penetration of contacts.
I tried to check for and handle this with a keyword snippet:
*CONTROL_CONTACT
$#  slsfac    rwpnal   islchk   shlthk   penopt   thkchg   orien    enmass
      0.0       0.0       0        1        1        0        2        0
$#  usrstr
      0
$#  sfric
      0.0
$#  ignore    frceng   skiprwg  outseg   spotstp  spotdel  spothin
      0         1        0        1        0        1        0.5
*END

Second Option: Ls-Dyna Restart systems in Workbench
Advantages: Easy to understand
Disadvantages: Limited features-especially full restart
I started with a small restart to delete parts that are not needed for the restart(the full restart does not seem to support that). I tried keyword snippets to delete those parts in the full restart but even though no error appeard the parts continued to exist.
With the small restart before the full restart, I can delete those parts. However the full restart only works when connected to the original Ls-Dyna system and not when connected to the small restart.

First Option: Export dynain file and import via external model into static structural
Advantages: No weird artifacts
Issues: The initial stress state is imported but based on the stresses at time 0, the stresses are not applied.

best regards,

Marco

[Marco Pedata]

In addition to my first post:

I tried to solve the problem via an explicit dynamics system.
Advantages: Multiple Loadsteps possible
Disadvantages: No Deletion of parts possible?
I defined the same model in explicit dynamics that i tried to solve via multiple Ls-Dyna systems because Ls-Dyna does not support multiple load steps.
When it came to Deleting parts for the second load step, however, I noticed no implemented feature.
Therefore, I wrote a command snippet to delete the bodies:
/PREP7
KDELE,62905
KDELE,62907
FINISH
I got an error, but do not know why.
Any assistance would be greatly appreciated!

Best regards,

Marco