Query on FCC_RateDependent Model for HCP Crystal Materials

[Farooq Hassan]

Dear Experts,

I am reaching out to inquire if anyone has experience using FCC_rate dependent model specifically for HCP crystals. If so, I would greatly appreciate it if you could provide insights on the major changes that need to be made in the calculatePlasticity.cc file to accommodate this model.

Your guidance and shared experiences would be invaluable in helping me navigate this process effectively.

Thank you for your time.

Best regards,

Muhammad Farooq Saleem

[Chaitali Patil]

Hi Muhammad, 

 

For rate dependent formulation, copy all files from plasticity/src/materialModels/crystalPlasticity/MaterialModels/RateDependentModel to your current crystalPlasticity directory and recompile the code. Make sure the files are correctly replaced and code is compiled properly. The same code can be used either for FCC or HCP systems.   You can use template from FCC_Random_RateDependent example for changes in the prm file. For example, you will need to add following additional lines in prm file to change from rate independent to rate dependent model.

set Enable User Material Model                   = true
set Enable User Material Model 1                  = true
set Advanced Rate Dependent Model enabled  = false
set Number of User Material Constants 1              = 12
set Number of User Material State Variables 1        = 100
set User Material Constants 1             = 1.0e-3, 0.04 , 1.0e-6 , 1.0e-6 ,  10000 , 10000,  0, 0, 0, 0 , 0.0, 0.0
set User Material State Variables Initial Values 1        = 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0.... (Total values here should match no. State Variables 1 ) 

You can also read more discussion on the parameters from plasticity/Training_Materials/Training_2021/Training Session 2.pdf

You will need to optimize the model parameters based on the material system, external boundary conditions, simulation setting etc . 

-Regards,

Chaitali