Model Change (Add/Remove Elements)

[CSAPL]

Documentation says about Model Change: "Element removal/reactivation can be used only in general analysis steps"
However , I am puzzeled if
Model Change , Add (or Remove Element)
can be inserted within a Geostatic , Soils Steps . or one should perform the model change (ADD or Remove) under specialized Static Step as done in a verification example in the Doc below where they first compress (first step) and then Remove element in a specialized step (second Step) and so on

Plesae advise


*STEP,NLGEOM
*STATIC
0.1,1.,0.1,0.1
*BOUNDARY
XMOVE,1, 1,-0.1
*NODE FILE, FREQ=99
U,
RF,
*EL FILE, FREQ=99
E,
S,
*END STEP
*STEP,NLGEOM
*STATIC
1.,1.
*MODEL CHANGE,REMOVE,TYPE=ELEMENT
REMOVE,
*END STEP
*STEP,NLGEOM
*STATIC
1.,1.
*BOUNDARY
YMOVE, 2, 2,0.
*END STEP
*STEP,NLGEOM
*STATIC
0.1,1.,0.1,0.1
*MODEL CHANGE,ADD,TYPE=ELEMENT
REMOVE,
*BOUNDARY,OP=NEW
XFIX, 1, 1
YFIX, 2, 2
XMOVE, 1, 1, 0.1
*END STEP

 

[hamadadf]

you can use model change in geostatic and soil steps

 

[CSAPL]

hamadadf
have you done staged construction through ABAQUS before, if yes i just want to double-check if Surfaces and Tie Constraint must be used to tie interface elements of the deactivated layer with the activated one being deformed so that the whole deactivated layer moves as a rigid body with the activated one

 

[hamadadf]

Hi CSAPL
i 've done staged excavation, so i needed only to deactivate sets, i didn't reactivate them so i didn't use interfaces. But yea i think what you are saying is right in case you want to activate them back (with strain=Yes ofcourse)