Error during simulation

ripening phenomena, dislocations, grainboundary topology
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Error during simulation

Post by betleenkim » Thu May 29, 2014 10:40 am

Dear Bernd

Recently, i try to simulate both of recrystallization of ferrite and formation of austenite during intercritical annealing process.

So i made a driving file as attached.

However, the simulation always stopped at 6 seconds.
Is there any way i can see what the problem is?

I attached all the files that are necessary for the simulation.

Thank you
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Re: Error during simulation

Post by Bernd » Tue Jun 03, 2014 5:02 pm

Hi betleenkim,

the error you found is a known bug which can appear with the recrystallization model in connection with multiple phases. I sent you an updated MICRESS (windows x64, version 6.153) via PM which solves the issue. Please accept my apologizes for your inconveniences!

With the newer version, the input has changed in three places (see also the attached driving file):
- time input data:
# Time-step?
# Options: fix ...[s] automatic automatic_limited
# Options: constant from_file
# Limits: (real) min./s, [max./s], [phase-field factor], [segregation factor]
5.e-5 1.

- concentration data:
# How shall the interval for updating diffusion coefficients
# data be set?
# Options: constant from_file
# Interval for updating diffusion coefficients data? [s]

- Phase diagram - input data:
# Which global relinearisation mode shall be used?
# Options: manual from_file none
manual 0.10000
# Input of the phase diagram of phase 0 and phase 1:
# --------------------------------------------------
# Which phase diagram is to be used?
# Options: database [local|global][start_value_{1|2}] linear linearTQ
# Relinearisation mode for interface 0 / 1
# Options: automatic manual from_file none


Posts: 41
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Re: Error during simulation

Post by betleenkim » Wed Jun 04, 2014 5:52 am

Dear Bernd

Thank you for your reply!! :D
It seems that the simulation is now going well.

I have some questions about input dislocation density in recrystallization simulation.

In the phase data part, i have to put "dislocation threshold for recrystallization" and in the seed data input part, there is another dislocation term "critical dislocation density". What is the difference between two density?

In addition, what is the meaning of minimum and maximum dislocation density for seed?

Best regard

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Re: Error during simulation

Post by gottfried » Thu Jun 05, 2014 4:05 pm

Dear betleenkim,

in fact, we have introduced in the 6.1 Version of Micress a residual value for the dislocation density/deformation energy of the new grains. This value is not zero as in the previous MIcress versions. This residual dislocation density is defined by a threshold value. Old grains have a density above this threshold. For example, I have performed simulations with value set to 1.6E+12 m-2 leading to a small residual ReX energy. The critical dislocation density or equivalent the critical ReX energy is required by the model to induce nucleation in locations where this critical value is at most exceeded. Finally the min. and max. dislocation density / energy in the seed definition of nuclei has been introduced in the past by Bernd in order to combine in the same Micress run solidification and ReX simulation. Only in this special case the parameters has not negligible values. In all other classical ReX simulations, their values are very small, f: ex. 8.E+11 m-2. You can see that their values are set smaller than the threshold density of a new grain!

I you have any further doubt, do not hesitate to ask via this forum

best regards

Gottfried Laschet

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