- first_dtInitial time step (in absolute time)
C++ Type:double
Description:Initial time step (in absolute time)
- log_dtTime step in log10(time)
C++ Type:double
Description:Time step in log10(time)
LogConstantDT
Sets the time step so that it is constant in the logarithmic space. The initial time step must be set up independently.
TimeStepper which imposes a time step constant in the logarithmic space
Input Parameters
- cutback_factor_at_failure0.5Factor to apply to timestep if it a time step fails to convergence.
Default:0.5
C++ Type:double
Options:
Description:Factor to apply to timestep if it a time step fails to convergence.
- growth_factor2Maximum ratio of new to previous timestep sizes following a step that required the time step to be cut due to a failed solve.
Default:2
C++ Type:double
Options:
Description:Maximum ratio of new to previous timestep sizes following a step that required the time step to be cut due to a failed solve.
- reset_dtFalseUse when restarting a calculation to force a change in dt.
Default:False
C++ Type:bool
Options:
Description:Use when restarting a calculation to force a change in dt.
Optional Parameters
- control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector<std::string>
Options:
Description:Adds user-defined labels for accessing object parameters via control logic.
- enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Options:
Description:Set the enabled status of the MooseObject.
Advanced Parameters
Input Files
- (modules/tensor_mechanics/test/tests/visco/burgers_creep.i)
- (modules/tensor_mechanics/test/tests/visco/gen_maxwell_driving.i)
- (modules/tensor_mechanics/test/tests/visco/gen_kv_driving.i)
- (modules/tensor_mechanics/test/tests/visco/visco_finite_strain.i)
- (modules/tensor_mechanics/test/tests/visco/gen_maxwell_relax.i)
- (modules/tensor_mechanics/test/tests/visco/visco_small_strain.i)
- (modules/tensor_mechanics/test/tests/visco/gen_kv_creep.i)
- (test/tests/time_steppers/logconstant_dt/logconstant_dt.i)
(modules/tensor_mechanics/test/tests/visco/burgers_creep.i)
[Mesh]
type = GeneratedMesh
dim = 3
nx = 1
ny = 1
nz = 1
elem_type = HEX8
displacements = 'disp_x disp_y disp_z'
[]
[Variables]
[./disp_x]
order = FIRST
family = LAGRANGE
[../]
[./disp_y]
order = FIRST
family = LAGRANGE
[../]
[./disp_z]
order = FIRST
family = LAGRANGE
[../]
[]
[AuxVariables]
[./stress_xx]
order = CONSTANT
family = MONOMIAL
[../]
[./strain_xx]
order = CONSTANT
family = MONOMIAL
[../]
[./creep_strain_xx]
order = CONSTANT
family = MONOMIAL
[../]
[]
[Kernels]
[./TensorMechanics]
displacements = 'disp_x disp_y disp_z'
use_displaced_mesh = true
[../]
[]
[AuxKernels]
[./stress_xx]
type = RankTwoAux
variable = stress_xx
rank_two_tensor = stress
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[./strain_xx]
type = RankTwoAux
variable = strain_xx
rank_two_tensor = total_strain
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[./creep_strain_xx]
type = RankTwoAux
variable = creep_strain_xx
rank_two_tensor = creep_strain
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[]
[BCs]
[./symmy]
type = DirichletBC
variable = disp_y
boundary = bottom
value = 0
[../]
[./symmx]
type = DirichletBC
variable = disp_x
boundary = left
value = 0
[../]
[./symmz]
type = DirichletBC
variable = disp_z
boundary = back
value = 0
[../]
[./axial_load]
type = NeumannBC
variable = disp_x
boundary = right
value = 10e6
[../]
[]
[Materials]
[./burgers]
type = GeneralizedKelvinVoigtModel
creep_modulus = '10e9'
creep_viscosity = '1 10'
poisson_ratio = 0.2
young_modulus = 10e9
[../]
[./stress]
type = ComputeMultipleInelasticStress
inelastic_models = 'creep'
[../]
[./creep]
type = LinearViscoelasticStressUpdate
[../]
[./strain]
type = ComputeIncrementalSmallStrain
displacements = 'disp_x disp_y disp_z'
[../]
[]
[UserObjects]
[./update]
type = LinearViscoelasticityManager
viscoelastic_model = burgers
[../]
[]
[Postprocessors]
[./stress_xx]
type = ElementAverageValue
variable = stress_xx
block = 'ANY_BLOCK_ID 0'
[../]
[./strain_xx]
type = ElementAverageValue
variable = strain_xx
block = 'ANY_BLOCK_ID 0'
[../]
[./creep_strain_xx]
type = ElementAverageValue
variable = creep_strain_xx
block = 'ANY_BLOCK_ID 0'
[../]
[]
[Preconditioning]
[./smp]
type = SMP
full = true
[../]
[]
[Executioner]
type = Transient
l_max_its = 50
l_tol = 1e-10
nl_max_its = 20
nl_rel_tol = 1e-10
nl_abs_tol = 1e-10
dtmin = 0.01
end_time = 100
[./TimeStepper]
type = LogConstantDT
first_dt = 0.1
log_dt = 0.1
[../]
[]
[Outputs]
file_base = burgers_creep_out
exodus = true
[]
(modules/tensor_mechanics/test/tests/visco/gen_maxwell_driving.i)
# Represents a unique Maxwell module with E = 10GPa and eta = 10 days with an imposed eigenstrain alpha = 0.001.
# The behavior is set up so that the creep strain is driven by both the elastic stress and the internal
# stress induced by the eigenstrain (E * alpha).
#
# In this test, the specimen is free of external stress (sigma = 0) so the creep deformation only derives from
# the eigenstrain. The total strain to be expected is:
# epsilon = alpha * (1 + t / eta)
# Both the stress and the elastic strain are 0.
#
[Mesh]
type = GeneratedMesh
dim = 3
nx = 1
ny = 1
nz = 1
elem_type = HEX8
displacements = 'disp_x disp_y disp_z'
[]
[Variables]
[./disp_x]
order = FIRST
family = LAGRANGE
[../]
[./disp_y]
order = FIRST
family = LAGRANGE
[../]
[./disp_z]
order = FIRST
family = LAGRANGE
[../]
[]
[AuxVariables]
[./stress_xx]
order = CONSTANT
family = MONOMIAL
[../]
[./strain_xx]
order = CONSTANT
family = MONOMIAL
[../]
[./creep_strain_xx]
order = CONSTANT
family = MONOMIAL
[../]
[]
[Kernels]
[./TensorMechanics]
displacements = 'disp_x disp_y disp_z'
use_displaced_mesh = true
[../]
[]
[AuxKernels]
[./stress_xx]
type = RankTwoAux
variable = stress_xx
rank_two_tensor = stress
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[./strain_xx]
type = RankTwoAux
variable = strain_xx
rank_two_tensor = total_strain
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[./creep_strain_xx]
type = RankTwoAux
variable = creep_strain_xx
rank_two_tensor = creep_strain
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[]
[BCs]
[./symmy]
type = DirichletBC
variable = disp_y
boundary = bottom
value = 0
[../]
[./symmx]
type = DirichletBC
variable = disp_x
boundary = left
value = 0
[../]
[./symmz]
type = DirichletBC
variable = disp_z
boundary = back
value = 0
[../]
[]
[Materials]
[./eigen]
type = ComputeEigenstrain
eigenstrain_name = eigen_true
eigen_base = '1e-3 1e-3 1e-3 0 0 0'
[../]
[./maxwell]
type = GeneralizedMaxwellModel
creep_modulus = '10e9'
creep_viscosity = '10'
poisson_ratio = 0.2
young_modulus = 10e9
driving_eigenstrain = eigen_true
[../]
[./stress]
type = ComputeMultipleInelasticStress
inelastic_models = 'creep'
[../]
[./creep]
type = LinearViscoelasticStressUpdate
[../]
[./strain]
type = ComputeIncrementalSmallStrain
displacements = 'disp_x disp_y disp_z'
eigenstrain_names = 'eigen_true'
[../]
[]
[UserObjects]
[./update]
type = LinearViscoelasticityManager
viscoelastic_model = maxwell
[../]
[]
[Postprocessors]
[./stress_xx]
type = ElementAverageValue
variable = stress_xx
block = 'ANY_BLOCK_ID 0'
[../]
[./strain_xx]
type = ElementAverageValue
variable = strain_xx
block = 'ANY_BLOCK_ID 0'
[../]
[./creep_strain_xx]
type = ElementAverageValue
variable = creep_strain_xx
block = 'ANY_BLOCK_ID 0'
[../]
[]
[Preconditioning]
[./smp]
type = SMP
full = true
[../]
[]
[Executioner]
type = Transient
l_max_its = 50
l_tol = 1e-8
nl_max_its = 20
nl_rel_tol = 1e-11
nl_abs_tol = 1e-8
dtmin = 0.01
end_time = 100
[./TimeStepper]
type = LogConstantDT
first_dt = 0.1
log_dt = 0.1
[../]
[]
[Outputs]
file_base = gen_maxwell_driving_out
exodus = true
[]
(modules/tensor_mechanics/test/tests/visco/gen_kv_driving.i)
# Represents a unique Maxwell module with E = 10GPa and eta = 10 days with an imposed eigenstrain alpha = 0.001.
# The behavior is set up so that the creep strain is driven by both the elastic stress and the internal
# stress induced by the eigenstrain (E * alpha).
#
# In this test, the specimen is free of external stress (sigma = 0) so the creep deformation only derives from
# the eigenstrain. The total strain to be expected is:
# epsilon = alpha * (1 + t / eta)
# Both the stress and the elastic strain are 0.
#
[Mesh]
type = GeneratedMesh
dim = 3
nx = 1
ny = 1
nz = 1
elem_type = HEX8
displacements = 'disp_x disp_y disp_z'
[]
[Variables]
[./disp_x]
order = FIRST
family = LAGRANGE
[../]
[./disp_y]
order = FIRST
family = LAGRANGE
[../]
[./disp_z]
order = FIRST
family = LAGRANGE
[../]
[]
[AuxVariables]
[./stress_xx]
order = CONSTANT
family = MONOMIAL
[../]
[./strain_xx]
order = CONSTANT
family = MONOMIAL
[../]
[./creep_strain_xx]
order = CONSTANT
family = MONOMIAL
[../]
[]
[Kernels]
[./TensorMechanics]
displacements = 'disp_x disp_y disp_z'
use_displaced_mesh = true
[../]
[]
[AuxKernels]
[./stress_xx]
type = RankTwoAux
variable = stress_xx
rank_two_tensor = stress
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[./strain_xx]
type = RankTwoAux
variable = strain_xx
rank_two_tensor = total_strain
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[./creep_strain_xx]
type = RankTwoAux
variable = creep_strain_xx
rank_two_tensor = creep_strain
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[]
[BCs]
[./symmy]
type = DirichletBC
variable = disp_y
boundary = bottom
value = 0
[../]
[./symmx]
type = DirichletBC
variable = disp_x
boundary = left
value = 0
[../]
[./symmz]
type = DirichletBC
variable = disp_z
boundary = back
value = 0
[../]
[]
[Materials]
[./eigen]
type = ComputeEigenstrain
eigenstrain_name = eigen_true
eigen_base = '1e-3 1e-3 1e-3 0 0 0'
[../]
[./kelvin_voigt]
type = GeneralizedKelvinVoigtModel
creep_modulus = ''
creep_viscosity = '10'
poisson_ratio = 0.2
young_modulus = 10e9
driving_eigenstrain = eigen_true
[../]
[./stress]
type = ComputeMultipleInelasticStress
inelastic_models = 'creep'
[../]
[./creep]
type = LinearViscoelasticStressUpdate
[../]
[./strain]
type = ComputeIncrementalSmallStrain
displacements = 'disp_x disp_y disp_z'
eigenstrain_names = 'eigen_true'
[../]
[]
[UserObjects]
[./update]
type = LinearViscoelasticityManager
viscoelastic_model = kelvin_voigt
[../]
[]
[Postprocessors]
[./stress_xx]
type = ElementAverageValue
variable = stress_xx
block = 'ANY_BLOCK_ID 0'
[../]
[./strain_xx]
type = ElementAverageValue
variable = strain_xx
block = 'ANY_BLOCK_ID 0'
[../]
[./creep_strain_xx]
type = ElementAverageValue
variable = creep_strain_xx
block = 'ANY_BLOCK_ID 0'
[../]
[]
[Preconditioning]
[./smp]
type = SMP
full = true
[../]
[]
[Executioner]
type = Transient
l_max_its = 50
l_tol = 1e-8
nl_max_its = 20
nl_rel_tol = 1e-11
nl_abs_tol = 1e-8
dtmin = 0.01
end_time = 100
[./TimeStepper]
type = LogConstantDT
first_dt = 0.1
log_dt = 0.1
[../]
[]
[Outputs]
file_base = gen_kv_driving_out
exodus = true
csv = true
[]
(modules/tensor_mechanics/test/tests/visco/visco_finite_strain.i)
[Mesh]
type = GeneratedMesh
dim = 3
nx = 1
ny = 1
nz = 1
elem_type = HEX8
displacements = 'disp_x disp_y disp_z'
[]
[Variables]
[./disp_x]
order = FIRST
family = LAGRANGE
[../]
[./disp_y]
order = FIRST
family = LAGRANGE
[../]
[./disp_z]
order = FIRST
family = LAGRANGE
[../]
[]
[AuxVariables]
[./stress_xx]
order = CONSTANT
family = MONOMIAL
[../]
[./strain_xx]
order = CONSTANT
family = MONOMIAL
[../]
[./creep_strain_xx]
order = CONSTANT
family = MONOMIAL
[../]
[]
[Kernels]
[./TensorMechanics]
displacements = 'disp_x disp_y disp_z'
use_displaced_mesh = true
[../]
[]
[AuxKernels]
[./stress_xx]
type = RankTwoAux
variable = stress_xx
rank_two_tensor = stress
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[./strain_xx]
type = RankTwoAux
variable = strain_xx
rank_two_tensor = total_strain
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[./creep_strain_xx]
type = RankTwoAux
variable = creep_strain_xx
rank_two_tensor = creep_strain
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[]
[BCs]
[./symmy]
type = DirichletBC
variable = disp_y
boundary = bottom
value = 0
[../]
[./symmx]
type = DirichletBC
variable = disp_x
boundary = left
value = 0
[../]
[./symmz]
type = DirichletBC
variable = disp_z
boundary = back
value = 0
[../]
[./axial_load]
type = NeumannBC
variable = disp_x
boundary = right
value = 10e6
[../]
[]
[Materials]
[./kelvin_voigt]
type = GeneralizedKelvinVoigtModel
creep_modulus = '10e9 10e9'
creep_viscosity = '1 10'
poisson_ratio = 0.2
young_modulus = 10e9
[../]
[./stress]
type = ComputeMultipleInelasticStress
inelastic_models = 'creep'
[../]
[./creep]
type = LinearViscoelasticStressUpdate
[../]
[./strain]
type = ComputeFiniteStrain
displacements = 'disp_x disp_y disp_z'
[../]
[]
[UserObjects]
[./update]
type = LinearViscoelasticityManager
viscoelastic_model = kelvin_voigt
[../]
[]
[Postprocessors]
[./stress_xx]
type = ElementAverageValue
variable = stress_xx
block = 'ANY_BLOCK_ID 0'
[../]
[./strain_xx]
type = ElementAverageValue
variable = strain_xx
block = 'ANY_BLOCK_ID 0'
[../]
[./creep_strain_xx]
type = ElementAverageValue
variable = creep_strain_xx
block = 'ANY_BLOCK_ID 0'
[../]
[]
[Preconditioning]
[./smp]
type = SMP
full = true
[../]
[]
[Executioner]
type = Transient
l_max_its = 100
l_tol = 1e-8
nl_max_its = 50
nl_rel_tol = 1e-8
nl_abs_tol = 1e-8
dtmin = 0.01
end_time = 100
[./TimeStepper]
type = LogConstantDT
first_dt = 0.1
log_dt = 0.1
[../]
[]
[Outputs]
file_base = visco_finite_strain_out
exodus = true
[]
(modules/tensor_mechanics/test/tests/visco/gen_maxwell_relax.i)
[Mesh]
type = GeneratedMesh
dim = 3
nx = 1
ny = 1
nz = 1
elem_type = HEX8
displacements = 'disp_x disp_y disp_z'
[]
[Variables]
[./disp_x]
order = FIRST
family = LAGRANGE
[../]
[./disp_y]
order = FIRST
family = LAGRANGE
[../]
[./disp_z]
order = FIRST
family = LAGRANGE
[../]
[]
[AuxVariables]
[./stress_xx]
order = CONSTANT
family = MONOMIAL
[../]
[./strain_xx]
order = CONSTANT
family = MONOMIAL
[../]
[./creep_strain_xx]
order = CONSTANT
family = MONOMIAL
[../]
[]
[Kernels]
[./TensorMechanics]
displacements = 'disp_x disp_y disp_z'
use_displaced_mesh = true
[../]
[]
[AuxKernels]
[./stress_xx]
type = RankTwoAux
variable = stress_xx
rank_two_tensor = stress
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[./strain_xx]
type = RankTwoAux
variable = strain_xx
rank_two_tensor = total_strain
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[./creep_strain_xx]
type = RankTwoAux
variable = creep_strain_xx
rank_two_tensor = creep_strain
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[]
[BCs]
[./symmy]
type = DirichletBC
variable = disp_y
boundary = bottom
value = 0
[../]
[./symmx]
type = DirichletBC
variable = disp_x
boundary = left
value = 0
[../]
[./symmz]
type = DirichletBC
variable = disp_z
boundary = back
value = 0
[../]
[./disp]
type = DirichletBC
variable = disp_x
boundary = right
value = 0.001
[../]
[]
[Materials]
[./maxwell]
type = GeneralizedMaxwellModel
creep_modulus = '3.333333e9 3.333333e9'
creep_viscosity = '1 10'
poisson_ratio = 0.2
young_modulus = 10e9
[../]
[./stress]
type = ComputeMultipleInelasticStress
inelastic_models = 'creep'
[../]
[./creep]
type = LinearViscoelasticStressUpdate
[../]
[./strain]
type = ComputeIncrementalSmallStrain
displacements = 'disp_x disp_y disp_z'
[../]
[]
[UserObjects]
[./update]
type = LinearViscoelasticityManager
viscoelastic_model = maxwell
[../]
[]
[Postprocessors]
[./stress_xx]
type = ElementAverageValue
variable = stress_xx
block = 'ANY_BLOCK_ID 0'
[../]
[./strain_xx]
type = ElementAverageValue
variable = strain_xx
block = 'ANY_BLOCK_ID 0'
[../]
[./creep_strain_xx]
type = ElementAverageValue
variable = creep_strain_xx
block = 'ANY_BLOCK_ID 0'
[../]
[]
[Preconditioning]
[./smp]
type = SMP
full = true
[../]
[]
[Executioner]
type = Transient
l_max_its = 50
l_tol = 1e-8
nl_max_its = 20
nl_rel_tol = 1e-8
nl_abs_tol = 1e-6
dtmin = 0.01
end_time = 100
[./TimeStepper]
type = LogConstantDT
first_dt = 0.1
log_dt = 0.1
[../]
[]
[Outputs]
file_base = gen_maxwell_relax_out
exodus = true
[]
(modules/tensor_mechanics/test/tests/visco/visco_small_strain.i)
[Mesh]
type = GeneratedMesh
dim = 3
nx = 1
ny = 1
nz = 1
elem_type = HEX8
displacements = 'disp_x disp_y disp_z'
[]
[Variables]
[./disp_x]
order = FIRST
family = LAGRANGE
[../]
[./disp_y]
order = FIRST
family = LAGRANGE
[../]
[./disp_z]
order = FIRST
family = LAGRANGE
[../]
[]
[AuxVariables]
[./stress_xx]
order = CONSTANT
family = MONOMIAL
[../]
[./strain_xx]
order = CONSTANT
family = MONOMIAL
[../]
[./creep_strain_xx]
order = CONSTANT
family = MONOMIAL
[../]
[]
[Kernels]
[./TensorMechanics]
displacements = 'disp_x disp_y disp_z'
use_displaced_mesh = true
[../]
[]
[AuxKernels]
[./stress_xx]
type = RankTwoAux
variable = stress_xx
rank_two_tensor = stress
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[./strain_xx]
type = RankTwoAux
variable = strain_xx
rank_two_tensor = total_strain
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[./creep_strain_xx]
type = RankTwoAux
variable = creep_strain_xx
rank_two_tensor = creep_strain
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[]
[BCs]
[./symmy]
type = DirichletBC
variable = disp_y
boundary = bottom
value = 0
[../]
[./symmx]
type = DirichletBC
variable = disp_x
boundary = left
value = 0
[../]
[./symmz]
type = DirichletBC
variable = disp_z
boundary = back
value = 0
[../]
[./axial_load]
type = NeumannBC
variable = disp_x
boundary = right
value = 10e6
[../]
[]
[Materials]
[./kelvin_voigt]
type = GeneralizedKelvinVoigtModel
creep_modulus = '10e9 10e9'
creep_viscosity = '1 10'
poisson_ratio = 0.2
young_modulus = 10e9
[../]
[./stress]
type = ComputeLinearViscoelasticStress
[../]
[./strain]
type = ComputeSmallStrain
displacements = 'disp_x disp_y disp_z'
[../]
[]
[UserObjects]
[./update]
type = LinearViscoelasticityManager
viscoelastic_model = kelvin_voigt
[../]
[]
[Postprocessors]
[./stress_xx]
type = ElementAverageValue
variable = stress_xx
block = 'ANY_BLOCK_ID 0'
[../]
[./strain_xx]
type = ElementAverageValue
variable = strain_xx
block = 'ANY_BLOCK_ID 0'
[../]
[./creep_strain_xx]
type = ElementAverageValue
variable = creep_strain_xx
block = 'ANY_BLOCK_ID 0'
[../]
[]
[Preconditioning]
[./smp]
type = SMP
full = true
[../]
[]
[Executioner]
type = Transient
l_max_its = 100
l_tol = 1e-8
nl_max_its = 50
nl_rel_tol = 1e-8
nl_abs_tol = 1e-8
dtmin = 0.01
end_time = 100
[./TimeStepper]
type = LogConstantDT
first_dt = 0.1
log_dt = 0.1
[../]
[]
[Outputs]
file_base = visco_small_strain_out
exodus = true
[]
(modules/tensor_mechanics/test/tests/visco/gen_kv_creep.i)
[Mesh]
type = GeneratedMesh
dim = 3
nx = 1
ny = 1
nz = 1
elem_type = HEX8
displacements = 'disp_x disp_y disp_z'
[]
[Variables]
[./disp_x]
order = FIRST
family = LAGRANGE
[../]
[./disp_y]
order = FIRST
family = LAGRANGE
[../]
[./disp_z]
order = FIRST
family = LAGRANGE
[../]
[]
[AuxVariables]
[./stress_xx]
order = CONSTANT
family = MONOMIAL
[../]
[./strain_xx]
order = CONSTANT
family = MONOMIAL
[../]
[./creep_strain_xx]
order = CONSTANT
family = MONOMIAL
[../]
[]
[Kernels]
[./TensorMechanics]
displacements = 'disp_x disp_y disp_z'
use_displaced_mesh = true
[../]
[]
[AuxKernels]
[./stress_xx]
type = RankTwoAux
variable = stress_xx
rank_two_tensor = stress
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[./strain_xx]
type = RankTwoAux
variable = strain_xx
rank_two_tensor = total_strain
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[./creep_strain_xx]
type = RankTwoAux
variable = creep_strain_xx
rank_two_tensor = creep_strain
index_j = 0
index_i = 0
execute_on = timestep_end
[../]
[]
[BCs]
[./symmy]
type = DirichletBC
variable = disp_y
boundary = bottom
value = 0
[../]
[./symmx]
type = DirichletBC
variable = disp_x
boundary = left
value = 0
[../]
[./symmz]
type = DirichletBC
variable = disp_z
boundary = back
value = 0
[../]
[./axial_load]
type = NeumannBC
variable = disp_x
boundary = right
value = 10e6
[../]
[]
[Materials]
[./kelvin_voigt]
type = GeneralizedKelvinVoigtModel
creep_modulus = '10e9 10e9'
creep_viscosity = '1 10'
poisson_ratio = 0.2
young_modulus = 10e9
[../]
[./stress]
type = ComputeMultipleInelasticStress
inelastic_models = 'creep'
[../]
[./creep]
type = LinearViscoelasticStressUpdate
[../]
[./strain]
type = ComputeIncrementalSmallStrain
displacements = 'disp_x disp_y disp_z'
[../]
[]
[UserObjects]
[./update]
type = LinearViscoelasticityManager
viscoelastic_model = kelvin_voigt
[../]
[]
[Postprocessors]
[./stress_xx]
type = ElementAverageValue
variable = stress_xx
block = 'ANY_BLOCK_ID 0'
[../]
[./strain_xx]
type = ElementAverageValue
variable = strain_xx
block = 'ANY_BLOCK_ID 0'
[../]
[./creep_strain_xx]
type = ElementAverageValue
variable = creep_strain_xx
block = 'ANY_BLOCK_ID 0'
[../]
[]
[Preconditioning]
[./smp]
type = SMP
full = true
[../]
[]
[Executioner]
type = Transient
l_max_its = 100
l_tol = 1e-8
nl_max_its = 50
nl_rel_tol = 1e-8
nl_abs_tol = 1e-8
dtmin = 0.01
end_time = 100
[./TimeStepper]
type = LogConstantDT
first_dt = 0.1
log_dt = 0.1
[../]
[]
[Outputs]
file_base = gen_kv_creep_out
exodus = true
[]
(test/tests/time_steppers/logconstant_dt/logconstant_dt.i)
[Mesh]
type = GeneratedMesh
dim = 2
nx = 10
ny = 10
[]
[Variables]
[./u]
[../]
[]
[Kernels]
[./diff]
type = CoefDiffusion
variable = u
coef = 0.1
[../]
[./time]
type = TimeDerivative
variable = u
[../]
[]
[BCs]
[./left]
type = DirichletBC
variable = u
boundary = left
value = 0
[../]
[./right]
type = DirichletBC
variable = u
boundary = right
value = 1
[../]
[]
[Executioner]
type = Transient
num_steps = 11
solve_type = PJFNK
petsc_options_iname = '-pc_type -pc_hypre_type'
petsc_options_value = 'hypre boomeramg'
# Pluggable TimeStepper System
[./TimeStepper]
type = LogConstantDT
log_dt = 0.2
first_dt = 0.1
[../]
[]
[Outputs]
exodus = true
[]