Learning Forum

[786959915]

I think the main function of the user-defined state subroutine is to output the bulk modulus in the first update, and the new pressure value and energy in the second update, i.e. the corresponding iflag=0 and iflag=1 parts, is this understood correctly?
Also, I have some questions about the initialization of some parameters in the user subroutine. For example, if I initialize the temperature tmp=293K, the temperature changes after running the subroutine, and if I call this subroutine later, does the temperature change to 293K?

[Pedram Samadian]

Hi,

You are right. As per LS-DYNA Keyword User’s Manual Vol. I Appendix II (LS-DYNA Keyword Manual), with a defined *EOS_USER_DEFINED card for a part, LS-DYNA first calls the EOS to calculate the bulk modulus and then calls it to update the pressure and internal energy.

About your second question, in LS-DYNA, variables like temperature are usually part of the state that are updated and passed through calls to the subroutine. This means the value of temperature at the end of a previous step will be carried into subsequent calls to the subroutine unless you overwrite it. The subroutine does not automatically reset the temperature to 293 K unless you explicitly reinitialize it in your code (i.e. you hardcode it in the code).

I hope this information answers your questions.

Thanks,

Pedram

 

 

[786959915]

Thank you very much for your reply