Sean Harvey
Ansys Employee

Hi Helen,

See the screenshot below.  It is in the Mechanical UI as an option as shown.

I answered on the other thread but I can repeat it here for the benefit of others.

MPCHG command allows you to change from one nonlinear material to another, but it does not support if there are different options.

per the help doc on MPCHG  "Changes the material number of the specified element. Between load steps in SOLUTION, material properties cannot be changed from linear to nonlinear, or from one nonlinear option to another."

So you can't switch the type of plasticity model, etc.  If you do, you will get an error like this.

 *** FATAL ***                           CP =     191.328   TIME= 14:33:48
 Change a nonlinear material model, 2, to another nonlinear material    
 model, 1, is not allowed for element type 186.