Restore grid configuration after ini disp (0,0,0)


I am modeling an excavation inside diaphragm walls in which some bottom upheave occurs. This deforms the grid at excavation bottom somewhat. Typically, I use this face to create a shell with the create-by-face keyword, but unless the deformation is small my shell won’t be planar. I tried to bring the grid back to its original geometry with

zone gridpoint initialize displacement (0,0,0) 

but this appears to just zero the field without moving the gridpoints. Is there a way I can achieve a planar shell after some base heave has occured?

Thank you in advance!

First - it isn’t clear to me why you need the faces to be planar. The structural element shells should work fine if they start out non-planar.

Second - there are a few options:

  1. You could run the model to that point in small strain, and turn on large strain afterwards.
  2. You could adjust the position of the gridpoint instead of the displacement - for example if the faces were in group ‘Fred’ and you wanted to make the bottom horizontal again at z position Z just use the command:

zone gridpoint initialize position-z Z range group “Fred”

Note that changing the gridpoint positions in this was does not affect the stress state of the zones they are connected to, and except for changes to zone volume that will subsequently affect gravititational loading it will not change equilibrium.

Thank you for your response.

I would prefer the shell to be planar bc I worry that it’s buckling behaviour could be affected if it is curved, for example.

I will try your suggestion regarding position, this seems like it could work.

Thank you,