(modules/phase_field/examples/multiphase/DerivativeMultiPhaseMaterial.i)
[Mesh]
type = GeneratedMesh
dim = 2
nx = 40
ny = 40
nz = 0
xmin = -12
xmax = 12
ymin = -12
ymax = 12
elem_type = QUAD4
[]
[GlobalParams]
# let's output all material properties for demonstration purposes
outputs = exodus
# prefactor on the penalty function kernels. The higher this value is, the
# more rigorously the constraint is enforced
penalty = 1e3
[]
#
# These AuxVariables hold the directly calculated free energy density in the
# simulation cell. They are provided for visualization purposes.
#
[AuxVariables]
[./local_energy]
order = CONSTANT
family = MONOMIAL
[../]
[./cross_energy]
order = CONSTANT
family = MONOMIAL
[../]
[]
[AuxKernels]
[./local_free_energy]
type = TotalFreeEnergy
variable = local_energy
interfacial_vars = 'c'
kappa_names = 'kappa_c'
additional_free_energy = cross_energy
[../]
#
# Helper kernel to cpompute the gradient contribution from interfaces of order
# parameters evolved using the ACMultiInterface kernel
#
[./cross_terms]
type = CrossTermGradientFreeEnergy
variable = cross_energy
interfacial_vars = 'eta1 eta2 eta3'
#
# The interface coefficient matrix. This should be symmetrical!
#
kappa_names = 'kappa11 kappa12 kappa13
kappa21 kappa22 kappa23
kappa31 kappa32 kappa33'
[../]
[]
[Variables]
[./c]
order = FIRST
family = LAGRANGE
#
# We set up a smooth cradial concentrtaion gradient
# The concentration will quickly change to adapt to the preset order
# parameters eta1, eta2, and eta3
#
[./InitialCondition]
type = SmoothCircleIC
x1 = 0.0
y1 = 0.0
radius = 5.0
invalue = 1.0
outvalue = 0.01
int_width = 10.0
[../]
[../]
[./eta1]
order = FIRST
family = LAGRANGE
[./InitialCondition]
type = FunctionIC
#
# Note: this initial conditions sets up a _sharp_ interface. Ideally
# we should start with a smooth interface with a width consistent
# with the kappa parameter supplied for the given interface.
#
function = 'r:=sqrt(x^2+y^2);if(r<=4,1,0)'
[../]
[../]
[./eta2]
order = FIRST
family = LAGRANGE
[./InitialCondition]
type = FunctionIC
function = 'r:=sqrt(x^2+y^2);if(r>4&r<=7,1,0)'
[../]
[../]
[./eta3]
order = FIRST
family = LAGRANGE
[./InitialCondition]
type = FunctionIC
function = 'r:=sqrt(x^2+y^2);if(r>7,1,0)'
[../]
[../]
[]
[Kernels]
#
# Cahn-Hilliard kernel for the concentration variable.
# Note that we are not using an interfcae kernel on this variable, but rather
# rely on the interface width enforced on the order parameters. This allows us
# to use a direct solve using the CahnHilliard kernel _despite_ only using first
# order elements.
#
[./c_res]
type = CahnHilliard
variable = c
f_name = F
args = 'eta1 eta2 eta3'
[../]
[./time]
type = TimeDerivative
variable = c
[../]
#
# Order parameter eta1
# Each order parameter is acted on by 4 kernels:
# 1. The stock time derivative deta_i/dt kernel
# 2. The Allen-Cahn kernel that takes a Dervative Material for the free energy
# 3. A gradient interface kernel that includes cross terms
# see http://mooseframework.org/wiki/PhysicsModules/PhaseField/DevelopingModels/MultiPhaseModels/ACMultiInterface/
# 4. A penalty contribution that forces the interface contributions h(eta)
# to sum up to unity
#
[./deta1dt]
type = TimeDerivative
variable = eta1
[../]
[./ACBulk1]
type = AllenCahn
variable = eta1
args = 'eta2 eta3 c'
mob_name = L1
f_name = F
[../]
[./ACInterface1]
type = ACMultiInterface
variable = eta1
etas = 'eta1 eta2 eta3'
mob_name = L1
kappa_names = 'kappa11 kappa12 kappa13'
[../]
[./penalty1]
type = SwitchingFunctionPenalty
variable = eta1
etas = 'eta1 eta2 eta3'
h_names = 'h1 h2 h3'
[../]
#
# Order parameter eta2
#
[./deta2dt]
type = TimeDerivative
variable = eta2
[../]
[./ACBulk2]
type = AllenCahn
variable = eta2
args = 'eta1 eta3 c'
mob_name = L2
f_name = F
[../]
[./ACInterface2]
type = ACMultiInterface
variable = eta2
etas = 'eta1 eta2 eta3'
mob_name = L2
kappa_names = 'kappa21 kappa22 kappa23'
[../]
[./penalty2]
type = SwitchingFunctionPenalty
variable = eta2
etas = 'eta1 eta2 eta3'
h_names = 'h1 h2 h3'
[../]
#
# Order parameter eta3
#
[./deta3dt]
type = TimeDerivative
variable = eta3
[../]
[./ACBulk3]
type = AllenCahn
variable = eta3
args = 'eta1 eta2 c'
mob_name = L3
f_name = F
[../]
[./ACInterface3]
type = ACMultiInterface
variable = eta3
etas = 'eta1 eta2 eta3'
mob_name = L3
kappa_names = 'kappa31 kappa32 kappa33'
[../]
[./penalty3]
type = SwitchingFunctionPenalty
variable = eta3
etas = 'eta1 eta2 eta3'
h_names = 'h1 h2 h3'
[../]
[]
[BCs]
[./Periodic]
[./All]
auto_direction = 'x y'
[../]
[../]
[]
[Materials]
# here we declare some of the model parameters: the mobilities and interface
# gradient prefactors. For this example we use arbitrary numbers. In an actual simulation
# physical mobilities would be used, and the interface gradient prefactors would
# be readjusted to the free energy magnitudes.
[./consts]
type = GenericConstantMaterial
prop_names = 'M kappa_c L1 L2 L3 kappa11 kappa12 kappa13 kappa21 kappa22 kappa23 kappa31 kappa32 kappa33'
prop_values = '0.2 0.75 1 1 1 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 '
[../]
# This material sums up the individual phase contributions. It is written to the output file
# (see GlobalParams section above) and can be used to check the constraint enforcement.
[./etasummat]
type = ParsedMaterial
f_name = etasum
args = 'eta1 eta2 eta3'
material_property_names = 'h1 h2 h3'
function = 'h1+h2+h3'
[../]
# The phase contribution factors for each material point are computed using the
# SwitchingFunctionMaterials. Each phase with an order parameter eta contributes h(eta)
# to the global free energy density. h is a function that switches smoothly from 0 to 1
[./switching1]
type = SwitchingFunctionMaterial
function_name = h1
eta = eta1
h_order = SIMPLE
[../]
[./switching2]
type = SwitchingFunctionMaterial
function_name = h2
eta = eta2
h_order = SIMPLE
[../]
[./switching3]
type = SwitchingFunctionMaterial
function_name = h3
eta = eta3
h_order = SIMPLE
[../]
# The barrier function adds a phase transformation energy barrier. It also
# Drives order parameters toward the [0:1] interval to avoid negative or larger than 1
# order parameters (these are set to 0 and 1 contribution by the switching functions
# above)
[./barrier]
type = MultiBarrierFunctionMaterial
etas = 'eta1 eta2 eta3'
[../]
# We use DerivativeParsedMaterials to specify three (very) simple free energy
# expressions for the three phases. All necessary derivatives are built automatically.
# In a real problem these expressions can be arbitrarily complex (or even provided
# by custom kernels).
[./phase_free_energy_1]
type = DerivativeParsedMaterial
f_name = F1
function = '(c-1)^2'
args = 'c'
[../]
[./phase_free_energy_2]
type = DerivativeParsedMaterial
f_name = F2
function = '(c-0.5)^2'
args = 'c'
[../]
[./phase_free_energy_3]
type = DerivativeParsedMaterial
f_name = F3
function = 'c^2'
args = 'c'
[../]
# The DerivativeMultiPhaseMaterial ties the phase free energies together into a global free energy.
# http://mooseframework.org/wiki/PhysicsModules/PhaseField/DevelopingModels/MultiPhaseModels/
[./free_energy]
type = DerivativeMultiPhaseMaterial
f_name = F
# we use a constant free energy (GeneriConstantmaterial property Fx)
fi_names = 'F1 F2 F3'
hi_names = 'h1 h2 h3'
etas = 'eta1 eta2 eta3'
args = 'c'
W = 1
[../]
[]
[Postprocessors]
# The total free energy of the simulation cell to observe the energy reduction.
[./total_free_energy]
type = ElementIntegralVariablePostprocessor
variable = local_energy
[../]
# for testing we also monitor the total solute amount, which should be conserved.
[./total_solute]
type = ElementIntegralVariablePostprocessor
variable = c
[../]
[]
[Preconditioning]
# This preconditioner makes sure the Jacobian Matrix is fully populated. Our
# kernels compute all Jacobian matrix entries.
# This allows us to use the Newton solver below.
[./SMP]
type = SMP
full = true
[../]
[]
[Executioner]
type = Transient
scheme = 'bdf2'
# Automatic differentiation provedes a _full_ Jacobian in this example
# so we can safely use NEWTON for a fast solve
solve_type = 'NEWTON'
l_max_its = 15
l_tol = 1.0e-6
nl_max_its = 50
nl_rel_tol = 1.0e-6
nl_abs_tol = 1.0e-6
start_time = 0.0
end_time = 150.0
[./TimeStepper]
type = SolutionTimeAdaptiveDT
dt = 0.1
[../]
[]
[Debug]
# show_var_residual_norms = true
[]
[Outputs]
execute_on = 'timestep_end'
exodus = true
[./table]
type = CSV
delimiter = ' '
[../]
[]