- viscoelastic_modelname of the LinearViscoelasticityBase object to manage
C++ Type:std::string
Description:name of the LinearViscoelasticityBase object to manage
Linear Viscoelasticity Manager
Manages the updating of the semi-implicit single-step first-order finite difference time-stepping scheme
Description
This updates the internal time-stepping scheme for linear viscoelastic materials (such as a GeneralizedKelvinVoigtModel or a GeneralizedMaxwellModel material) at the beginning of each time step. Including a LinearViscoelasticStressUpdate in the simulation is required for the linear viscoelastic strains to be updated properly.
Example Input File Syntax
[./update]
type = LinearViscoelasticityManager
viscoelastic_model = kelvin_voigt
[../]
/opt/civet/build_0/moose/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
[]
Input Parameters
- blockThe list of block ids (SubdomainID) that this object will be applied
C++ Type:std::vector
Options:
Description:The list of block ids (SubdomainID) that this object will be applied
- creep_strain_namecreep_strainname of the creep strain tensor used for the viscoelastic update
Default:creep_strain
C++ Type:std::string
Options:
Description:name of the creep strain tensor used for the viscoelastic update
- elastic_strain_nameelastic_strainname of the elastic strain tensor used for the viscoelastic update
Default:elastic_strain
C++ Type:std::string
Options:
Description:name of the elastic strain tensor used for the viscoelastic update
- stress_namestressname of the stress tensor used for the viscoelastic update
Default:stress
C++ Type:std::string
Options:
Description:name of the stress tensor used for the viscoelastic update
Optional Parameters
- allow_duplicate_execution_on_initialFalseIn the case where this UserObject is depended upon by an initial condition, allow it to be executed twice during the initial setup (once before the IC and again after mesh adaptivity (if applicable).
Default:False
C++ Type:bool
Options:
Description:In the case where this UserObject is depended upon by an initial condition, allow it to be executed twice during the initial setup (once before the IC and again after mesh adaptivity (if applicable).
- control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector
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.
- implicitTrueDetermines whether this object is calculated using an implicit or explicit form
Default:True
C++ Type:bool
Options:
Description:Determines whether this object is calculated using an implicit or explicit form
- seed0The seed for the master random number generator
Default:0
C++ Type:unsigned int
Options:
Description:The seed for the master random number generator
- use_displaced_meshFalseWhether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.
Default:False
C++ Type:bool
Options:
Description:Whether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.
Advanced Parameters
Input Files
- modules/tensor_mechanics/test/tests/visco/visco_finite_strain.i
- modules/tensor_mechanics/test/tests/visco/visco_small_strain.i
- modules/tensor_mechanics/test/tests/visco/burgers_creep.i
- modules/tensor_mechanics/test/tests/visco/gen_maxwell_relax.i
- modules/tensor_mechanics/test/tests/visco/gen_maxwell_driving.i
- modules/tensor_mechanics/test/tests/visco/gen_kv_creep.i
- modules/tensor_mechanics/test/tests/visco/gen_kv_driving.i
- modules/tensor_mechanics/test/tests/scalar_material_damage/scalar_material_damage_creep.i
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/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/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_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/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_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
[]
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/scalar_material_damage/scalar_material_damage_creep.i
# This is a basic test of the system for continuum damage mechanics
# materials. It uses ScalarMaterialDamage for the damage model,
# which simply gets its damage index from another material. In this
# case, we prescribe the evolution of the damage index using a
# function. A single element has a fixed prescribed displacement
# on one side that puts the element in tension, and then the
# damage index evolves from 0 to 1 over time, and this verifies
# that the stress correspondingly drops to 0.
[GlobalParams]
displacements = 'disp_x disp_y disp_z'
[]
[Mesh]
type = GeneratedMesh
dim = 3
nx = 1
ny = 1
nz = 1
elem_type = HEX8
[]
[AuxVariables]
[damage_index]
order = CONSTANT
family = MONOMIAL
[]
[]
[Modules/TensorMechanics/Master]
[all]
strain = SMALL
incremental = true
add_variables = true
generate_output = 'stress_xx strain_xx creep_strain_xx'
[]
[]
[AuxKernels]
[damage_index]
type = MaterialRealAux
variable = damage_index
property = damage_index_prop
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 = DirichletBC
variable = disp_x
boundary = right
value = 0.01
[]
[]
[Functions]
[damage_evolution]
type = PiecewiseLinear
xy_data = '0.0 0.0
0.1 0.0
2.1 2.0'
[]
[]
[Materials]
[damage_index]
type = GenericFunctionMaterial
prop_names = damage_index_prop
prop_values = damage_evolution
[]
[damage]
type = ScalarMaterialDamage
damage_index = damage_index_prop
[]
[stress]
type = ComputeMultipleInelasticStress
damage_model = damage
inelastic_models = 'creep'
[]
[kelvin_voigt]
type = GeneralizedKelvinVoigtModel
creep_modulus = '10e9 10e9'
creep_viscosity = '1 10'
poisson_ratio = 0.2
young_modulus = 10e9
[]
[creep]
type = LinearViscoelasticStressUpdate
[]
[]
[UserObjects]
[./update]
type = LinearViscoelasticityManager
viscoelastic_model = kelvin_voigt
[../]
[]
[Postprocessors]
[stress_xx]
type = ElementAverageValue
variable = stress_xx
[]
[strain_xx]
type = ElementAverageValue
variable = strain_xx
[]
[./creep_strain_xx]
type = ElementAverageValue
variable = creep_strain_xx
[../]
[damage_index]
type = ElementAverageValue
variable = damage_index
[]
[]
[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-10
nl_abs_tol = 1e-8
dt = 0.1
dtmin = 0.001
end_time = 1.1
[]
[Outputs]
csv=true
exodus = true
[]