ACS SASSI has a process to simulate a model with non-linear materials.

ACS-SASSI User Interface has commands to change a Linear model so it can be used in a non-linear analysis

* Example of splitting a model for Creating a Non-Linear model

* Load a starting model and copy it to create a Panel Model
ACTM,1
INP, ./Model1.pre,C:/Models/Demo/ *Starting model
* Move to copy of the model to create a panel model later
CPMODEL,2
*delete the shell groups from this model
gdel,3,4
gdel,7,10
...
GCOM
ACTM,2
*create the panel model
WALLFLR
* further refine the panels
...

ACTM,1
*Recombine the model panels with the non-shell elements
MERGEPANEL,2

Note(s) : General Nonlinear example command list or *.pre file. The first ellipsis is a list GDEL commands to remove the shell groups from the initial model. The second ellipsis will contain different commands depending on the model.