My material needs to change from one set of temperature dependent thermal conductivity values, when it is a powder, to another set of values when it changes to a solid as soon as it reaches a specific temperature value. I am performing an uncoupled thermal analysis. I used the DFLUX subroutine to simulate the heat flux during SLS processing. I've read about UMATHT but can't find any information on how to switch between material property data.
Dear Carlo Olivier,
by using the UMATHT subroutine you could model the constitutive equations that define the material's response. I suppose that thermal conductivity can be defined as an internal state variable dependent on temperature.
The question is if you have a constitutive model for the case you would like to study.
Regards,
Anargyros
Hello,
If I understand correctly your problem, you want to take into account a dependancy of the thermal conductivity to the temperature. Isn't it possible using the built-in capabilities of Abaqus (no need of an user subroutine) by specifying the thermal conductivity for various temperature as a table?
Here is a copy/paste of the documentation (section 23.2.2). The interesting item is the third.
A material's thermal conductivity:
- must be defined for “Uncoupled heat transfer analysis,” Section 6.5.2; “Fully coupled thermal-stress analysis,” Section 6.5.4; and “Coupled thermal-electrical analysis,” Section 6.7.2;
- must be defined for an Abaqus/CFD analysis when the energy equation is active (“Energy equation” in “Incompressible fluid dynamic analysis,” Section 6.6.2);
- can be linear or nonlinear (by defining it as a function of temperature);
- can be isotropic, orthotropic, or fully anisotropic; and
- can be specified as a function of temperature and/or field variables
Best regards,
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