Place randomly distributed nuclei
Posted: Thu Feb 14, 2019 3:39 am
Hi all, this is my first post here...
I'm doing a 2D benchmarking nucleation and grain growth simulation with MICRESS and I want to place randomly distributed grains into a bulk domain (i.e. no initial grain boundaries). The bulk domain is set to have a recrystallization energy of 3 MPa and the nuclei have 0 MPa.
I want to place randomly distributed nuclei (i.e. "bulk" nuclei in the nucleation option) so I can perform the JMAK analysis on fraction recrystallized. I tuned shield distance and shield time, but so far the nuclei does not seem to be randomly placed throughout the simulation domain (see the attached image). For example, the first 6 nuclei all locate in the very bottom of the domain and some seem to lie on the same horizontal line. I wonder if there's a way to randomly place bulk nuclei within MICRESS.
The "Data for Further Nucleation" section in my MICRESS "*.in" file is included below. My domain size is 250x250 micrometers.
Thanks in advance,
Billy
# Data for further nucleation
# ===========================
# Enable further nucleation?
# Options: nucleation nucleation_symm no_nucleation [verbose|no_verbose]
nucleation
# Additional output for nucleation?
# Options: out_nucleation no_out_nucleation
no_out_nucleation
#
# Number of types of seeds?
1
#
# Input for seed type 1:
# ----------------------
# Type of 'position' of the seeds?
# Options: bulk region interface triple quadruple front [restrictive]
bulk
# Phase of new grains (integer) [unresolved|add_to_grain]?
1
# Reference phase (integer) [min. and max. fraction (real)]?
1
# Which nucleation model shall be used?
# Options: seed_undercooling seed_density
seed_undercooling
# maximum number of new nuclei 1?
# (set negative for unlimited number)
20
# Grain radius [micrometers]?
0.500000
# Choice of growth mode:
# Options: stabilisation analytical_curvature
stabilisation
# critical recrystallisation energy [J/cm**3 or MPa]?
1.0000
# Determination of nuclei orientations?
# Options: random fix fix_direction parent_relation
random
# Shield effect:
# Shield time [s] [shield phase or group number] ?
1000.00
# Shield distance [micrometers] [ nucleation distance [micrometers] ]?
30.000 30.000
# Shall categorizaton be applied to this seed type?
# Options: categorize {number} no_categorize
categorize
# Input of minimal and maximal energy of the nuclei:
# Minimum of recrystallisation energy? [J/cm**3 or MPa]
0.0000
# Maximum of recrystallisation energy? [J/cm**3 or MPa]
0.0000
# Nucleation range
# min. nucleation temperature for seed type 1 [K]
0
# max. nucleation temperature for seed type 1 [K]
2000.000
# Time between checks for nucleation? [s]
# Options: constant from_file
constant
# Time interval [s]
1.50000E-02
# Shall random noise be applied?
# Options: nucleation_noise no_nucleation_noise
nucleation_noise
# Factor for random noise?
# (applied as DeltaT -> (1+Factor*(RAND-1/2))*DeltaT)
1.000E-03
#
# Seed for random-number generator initialisation
# -----------------------------------------------
22
# Max. number of simultaneous nucleations?
# ----------------------------------------
# (set to 0 for automatic)
0
#
# Shall metastable small seeds be killed?
# ---------------------------------------
# Options: kill_metastable no_kill_metastable
no_kill_metastable
#
I'm doing a 2D benchmarking nucleation and grain growth simulation with MICRESS and I want to place randomly distributed grains into a bulk domain (i.e. no initial grain boundaries). The bulk domain is set to have a recrystallization energy of 3 MPa and the nuclei have 0 MPa.
I want to place randomly distributed nuclei (i.e. "bulk" nuclei in the nucleation option) so I can perform the JMAK analysis on fraction recrystallized. I tuned shield distance and shield time, but so far the nuclei does not seem to be randomly placed throughout the simulation domain (see the attached image). For example, the first 6 nuclei all locate in the very bottom of the domain and some seem to lie on the same horizontal line. I wonder if there's a way to randomly place bulk nuclei within MICRESS.
The "Data for Further Nucleation" section in my MICRESS "*.in" file is included below. My domain size is 250x250 micrometers.
Thanks in advance,
Billy
# Data for further nucleation
# ===========================
# Enable further nucleation?
# Options: nucleation nucleation_symm no_nucleation [verbose|no_verbose]
nucleation
# Additional output for nucleation?
# Options: out_nucleation no_out_nucleation
no_out_nucleation
#
# Number of types of seeds?
1
#
# Input for seed type 1:
# ----------------------
# Type of 'position' of the seeds?
# Options: bulk region interface triple quadruple front [restrictive]
bulk
# Phase of new grains (integer) [unresolved|add_to_grain]?
1
# Reference phase (integer) [min. and max. fraction (real)]?
1
# Which nucleation model shall be used?
# Options: seed_undercooling seed_density
seed_undercooling
# maximum number of new nuclei 1?
# (set negative for unlimited number)
20
# Grain radius [micrometers]?
0.500000
# Choice of growth mode:
# Options: stabilisation analytical_curvature
stabilisation
# critical recrystallisation energy [J/cm**3 or MPa]?
1.0000
# Determination of nuclei orientations?
# Options: random fix fix_direction parent_relation
random
# Shield effect:
# Shield time [s] [shield phase or group number] ?
1000.00
# Shield distance [micrometers] [ nucleation distance [micrometers] ]?
30.000 30.000
# Shall categorizaton be applied to this seed type?
# Options: categorize {number} no_categorize
categorize
# Input of minimal and maximal energy of the nuclei:
# Minimum of recrystallisation energy? [J/cm**3 or MPa]
0.0000
# Maximum of recrystallisation energy? [J/cm**3 or MPa]
0.0000
# Nucleation range
# min. nucleation temperature for seed type 1 [K]
0
# max. nucleation temperature for seed type 1 [K]
2000.000
# Time between checks for nucleation? [s]
# Options: constant from_file
constant
# Time interval [s]
1.50000E-02
# Shall random noise be applied?
# Options: nucleation_noise no_nucleation_noise
nucleation_noise
# Factor for random noise?
# (applied as DeltaT -> (1+Factor*(RAND-1/2))*DeltaT)
1.000E-03
#
# Seed for random-number generator initialisation
# -----------------------------------------------
22
# Max. number of simultaneous nucleations?
# ----------------------------------------
# (set to 0 for automatic)
0
#
# Shall metastable small seeds be killed?
# ---------------------------------------
# Options: kill_metastable no_kill_metastable
no_kill_metastable
#