Learning Forum

[Yoker]

Hello Team I want to create a new mechanical constitutive of materials though USERMAT. Under the constitutive, machanical properties of material will change with concentration field. See the simple fomula below:
σ = (1-C)Dε
where C is the normalized concentration, D is the elastic stress-strain matrix.
Perform the structure-diffusion analysis though PLANE223 coupled-field solid element, so we can get the concentration data of each nodes and elements. My question is how can I import the CONC data into USERMAT? I have tried subroutine "emsget" but failed. Maybe it is because I did not code it correctly.
Thanks for your help!

[David Weed]

, I don't believe that this is currently supported. I'm checking on this and will follow up soon.

[Yoker]

thanks for your attention. I supposed it is very similar to the situation that Young's modulus changes with temperature and in many cases temperature is non-uniform. I think there should be an approach that can replace the temperature field to other field variables (such as concentration field, current field, magnetic field or radiation field and so on).

[David Weed]

Hi Yoker, in speaking with development again, they asked the following:

Do you know if this stress equation below is the only modification the user wants to make to the standard constitutive model? Does this stress affect anything else in the structural part of the model?

[manuel.petersmann]

Hi Yoker,

For what you are trying to do, it should be sufficient to use field-dependent data (TBFIELD + TBDATA) and then define a linear dependence there directly.

BR, Manuel