Compute Reduced Order Eigenstrain

accepts eigenstrains and computes a reduced order eigenstrain for consistency in the order of strain and eigenstrains.

Description

Since strain is a function of the derivative of displacements, the strain field is one order lower than the displacement field. If the element is linear, the strain field will be constant; if the element is quadratic, the strain field will be linear.

This being the case, eigenstrains that affect the strain need to be of the same order as the strain. A thermal strain taken from temperatures at nodes will vary according to the order of the temperature and not the strain field. Using a thermal strain one order higher than the strain field can lead to oscillations in the overall strain and stress.

This class accepts eigenstrains and computes a reduced order eigenstrain. If the primary solution variable field is linear, the resulting eigenstrain will be constant in an element using volume weighting. If the primary solution variable field is quadratic, the resulting eigenstrain will be linear in an element using a least squares procedure.

warning

ComputeReducedOrderEigenstrain object for RankTwoTensor eigenstrains with the TensorMechanicsAction setting automatic_eigenstrain_names = true, eigenstrains listed as MaterialADConverter input tensors will not be included in the eigenstrain_names list passed. Set the automatic/_eigenstrain/_names = false and populate this list manually if these components need to be included.

Example Input File syntax

[./reduced_order_eigenstrain]
  type = ComputeReducedOrderEigenstrain
  input_eigenstrain_names = 'thermal_eigenstrain'
  eigenstrain_name = 'reduced_eigenstrain'
[../]

The eigenstrain_name parameter value must also be set for the strain calculator, and an example parameter setting is shown below:

[Modules]
  [./TensorMechanics]
    [./Master]
      [./all]
        add_variables = true
        strain = SMALL
        incremental = true
        temperature = temp2
        eigenstrain_names = 'reduced_eigenstrain' #'thermal_eigenstrain'
      [../]
    [../]
  [../]
[]

Input Parameters

eigenstrain_nameMaterial property name for the eigenstrain tensor computed by this model. IMPORTANT: The name of this property must also be provided to the strain calculator.
C++ Type:std::string
Controllable:No
Description:Material property name for the eigenstrain tensor computed by this model. IMPORTANT: The name of this property must also be provided to the strain calculator.
input_eigenstrain_namesList of eigenstrains to be applied in this strain calculation
C++ Type:std::vector<MaterialPropertyName>
Controllable:No
Description:List of eigenstrains to be applied in this strain calculation

Required Parameters

base_nameOptional parameter that allows the user to define multiple mechanics material systems on the same block, i.e. for multiple phases
C++ Type:std::string
Controllable:No
Description:Optional parameter that allows the user to define multiple mechanics material systems on the same block, i.e. for multiple phases
blockThe list of blocks (ids or names) that this object will be applied
C++ Type:std::vector<SubdomainName>
Controllable:No
Description:The list of blocks (ids or names) that this object will be applied
boundaryThe list of boundaries (ids or names) from the mesh where this object applies
C++ Type:std::vector<BoundaryName>
Controllable:No
Description:The list of boundaries (ids or names) from the mesh where this object applies
computeTrueWhen false, MOOSE will not call compute methods on this material. The user must call computeProperties() after retrieving the MaterialBase via MaterialBasePropertyInterface::getMaterialBase(). Non-computed MaterialBases are not sorted for dependencies.
Default:True
C++ Type:bool
Controllable:No
Description:When false, MOOSE will not call compute methods on this material. The user must call computeProperties() after retrieving the MaterialBase via MaterialBasePropertyInterface::getMaterialBase(). Non-computed MaterialBases are not sorted for dependencies.
constant_onNONEWhen ELEMENT, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps.When SUBDOMAIN, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped
Default:NONE
C++ Type:MooseEnum
Options:NONE, ELEMENT, SUBDOMAIN
Controllable:No
Description:When ELEMENT, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps.When SUBDOMAIN, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped
declare_suffixAn optional suffix parameter that can be appended to any declared properties. The suffix will be prepended with a '_' character.
C++ Type:MaterialPropertyName
Controllable:No
Description:An optional suffix parameter that can be appended to any declared properties. The suffix will be prepended with a '_' character.
prop_getter_suffixAn optional suffix parameter that can be appended to any attempt to retrieve/get material properties. The suffix will be prepended with a '_' character.
C++ Type:MaterialPropertyName
Controllable:No
Description:An optional suffix parameter that can be appended to any attempt to retrieve/get material properties. The suffix will be prepended with a '_' character.

Optional Parameters

control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector<std::string>
Controllable:No
Description:Adds user-defined labels for accessing object parameters via control logic.
enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Controllable:Yes
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
Controllable:No
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
Controllable:No
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
Controllable:No
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

output_propertiesList of material properties, from this material, to output (outputs must also be defined to an output type)
C++ Type:std::vector<std::string>
Controllable:No
Description:List of material properties, from this material, to output (outputs must also be defined to an output type)
outputsnone Vector of output names where you would like to restrict the output of variables(s) associated with this object
Default:none
C++ Type:std::vector<OutputName>
Controllable:No
Description:Vector of output names where you would like to restrict the output of variables(s) associated with this object

Outputs Parameters

(../moose/modules/tensor_mechanics/test/tests/eigenstrain/reducedOrderRZLinear.i)

#
# This test checks whether the ComputeReducedOrderEigenstrain is functioning properly.
#
# If instead of 'reduced_eigenstrain', 'thermal_eigenstrain' is given to
# eigenstrain_names in the Modules/TensorMechanics/Master/all block, the output will be
# quite different.
#
# Open the reducedOrderRZLinear_out_hydro_0001.csv file and plot the hydro variables as
# a function of x.  For the reduced order case, the values are smooth across each of the
# two elements with a jump upward from the left element to the right element.  However,
# when not using 'reduced_order_eigenstrain', a jump downward appears from the left
# element to the right element.
#

[GlobalParams]
  displacements = 'disp_x disp_y'
  volumetric_locking_correction = false
[]

[Problem]
  coord_type = RZ
[]

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 2
  ny = 1
  xmax = 3
  xmin = 1
  ymax = 1
  ymin = 0
  #second_order = true
[]

[Functions]
  [./tempLinear]
    type = ParsedFunction
    expression = '715-5*x'
  [../]
  [./tempQuadratic]
    type = ParsedFunction
    expression = '2.5*x*x-15*x+722.5'
  [../]
  [./tempCubic]
    type = ParsedFunction
    expression = '-1.25*x*x*x+11.25*x*x-33.75*x+733.75'
  [../]
[]

[Variables]
  [./temp]
    order = FIRST
    family = LAGRANGE
    initial_condition = 700
  [../]
[]

[AuxVariables]
  [./hydro_constant]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./hydro_first]
    order = FIRST
    family = MONOMIAL
  [../]
  [./hydro_second]
    order = SECOND
    family = MONOMIAL
  [../]
  [./sxx_constant]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./sxx_first]
    order = FIRST
    family = MONOMIAL
  [../]
  [./sxx_second]
    order = SECOND
    family = MONOMIAL
  [../]
  [./szz_constant]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./szz_first]
    order = FIRST
    family = MONOMIAL
  [../]
  [./szz_second]
    order = SECOND
    family = MONOMIAL
  [../]
  [./temp2]
    order = FIRST
    family = LAGRANGE
    initial_condition = 700
  [../]
[]

[Modules]
  [./TensorMechanics]
    [./Master]
      [./all]
        add_variables = true
        strain = SMALL
        incremental = true
        temperature = temp2
        eigenstrain_names = 'reduced_eigenstrain' #'thermal_eigenstrain'
      [../]
    [../]
  [../]
[]

[Kernels]
  [./heat]
    type = Diffusion
    variable = temp
  [../]
[]

[AuxKernels]
  [./hydro_constant_aux]
    type = RankTwoScalarAux
    variable = hydro_constant
    rank_two_tensor = stress
    scalar_type = Hydrostatic
  [../]
  [./hydro_first_aux]
    type = RankTwoScalarAux
    variable = hydro_first
    rank_two_tensor = stress
    scalar_type = Hydrostatic
  [../]
  [./hydro_second_aux]
    type = RankTwoScalarAux
    variable = hydro_second
    rank_two_tensor = stress
    scalar_type = Hydrostatic
  [../]
  [./sxx_constant_aux]
    type = RankTwoAux
    variable = sxx_constant
    rank_two_tensor = stress
    index_i = 0
    index_j = 0
  [../]
  [./sxx_first_aux]
    type = RankTwoAux
    variable = sxx_first
    rank_two_tensor = stress
    index_i = 0
    index_j = 0
  [../]
  [./sxx_second_aux]
    type = RankTwoAux
    variable = sxx_second
    rank_two_tensor = stress
    index_i = 0
    index_j = 0
  [../]
  [./szz_constant_aux]
    type = RankTwoAux
    variable = szz_constant
    rank_two_tensor = stress
    index_i = 2
    index_j = 2
  [../]
  [./szz_first_aux]
    type = RankTwoAux
    variable = szz_first
    rank_two_tensor = stress
    index_i = 2
    index_j = 2
  [../]
  [./szz_second_aux]
    type = RankTwoAux
    variable = szz_second
    rank_two_tensor = stress
    index_i = 2
    index_j = 2
  [../]
  [./temp2]
    type = FunctionAux
    variable = temp2
    function = tempLinear
    execute_on = timestep_begin
  [../]
[]

[BCs]
  [./no_x]
    type = DirichletBC
    variable = disp_x
    boundary = left
    value = 0.0
  [../]
  [./no_y]
    type = DirichletBC
    variable = disp_y
    boundary = 'bottom top'
    value = 0.0
  [../]

  [./temp_right]
    type = DirichletBC
    variable = temp
    boundary = right
    value = 700
  [../]
  [./temp_left]
    type = DirichletBC
    variable = temp
    boundary = left
    value = 710
  [../]
[]


[Materials]
  [./fuel_stress]
    type = ComputeFiniteStrainElasticStress
  [../]
  [./elasticity_tensor]
    type = ComputeIsotropicElasticityTensor
    youngs_modulus = 1
    poissons_ratio = 0
  [../]
  [./fuel_thermal_expansion]
    type = ComputeThermalExpansionEigenstrain
    thermal_expansion_coeff = 1
    temperature = temp2
    stress_free_temperature = 700.0
    eigenstrain_name = 'thermal_eigenstrain'
  [../]
  [./reduced_order_eigenstrain]
    type = ComputeReducedOrderEigenstrain
    input_eigenstrain_names = 'thermal_eigenstrain'
    eigenstrain_name = 'reduced_eigenstrain'
  [../]
[]


[Preconditioning]
  [./SMP]
    type = SMP
    full = true
  [../]
[]

[Executioner]
  type = Transient
  solve_type = 'PJFNK'

  petsc_options = '-snes_ksp_ew '
  petsc_options_iname = '-ksp_gmres_restart -pc_type -pc_hypre_type'
  petsc_options_value = '70 hypre boomeramg'

  num_steps = 1
  nl_rel_tol = 1e-8 #1e-12
[]

[Postprocessors]
  [./_dt]
    type = TimestepSize
  [../]
[]

[VectorPostprocessors]
  [./hydro]
    type = LineValueSampler
    warn_discontinuous_face_values = false
    num_points = 100
    start_point = '1 0.07e-3 0'
    end_point = '3 0.07e-3 0'
    sort_by = x
    variable = 'hydro_constant hydro_first hydro_second temp2 disp_x disp_y'
  [../]
[]

[Outputs]
  exodus = true
  csv = true
[]

(../moose/modules/tensor_mechanics/test/tests/eigenstrain/reducedOrderRZLinear.i)

#
# This test checks whether the ComputeReducedOrderEigenstrain is functioning properly.
#
# If instead of 'reduced_eigenstrain', 'thermal_eigenstrain' is given to
# eigenstrain_names in the Modules/TensorMechanics/Master/all block, the output will be
# quite different.
#
# Open the reducedOrderRZLinear_out_hydro_0001.csv file and plot the hydro variables as
# a function of x.  For the reduced order case, the values are smooth across each of the
# two elements with a jump upward from the left element to the right element.  However,
# when not using 'reduced_order_eigenstrain', a jump downward appears from the left
# element to the right element.
#

[GlobalParams]
  displacements = 'disp_x disp_y'
  volumetric_locking_correction = false
[]

[Problem]
  coord_type = RZ
[]

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 2
  ny = 1
  xmax = 3
  xmin = 1
  ymax = 1
  ymin = 0
  #second_order = true
[]

[Functions]
  [./tempLinear]
    type = ParsedFunction
    expression = '715-5*x'
  [../]
  [./tempQuadratic]
    type = ParsedFunction
    expression = '2.5*x*x-15*x+722.5'
  [../]
  [./tempCubic]
    type = ParsedFunction
    expression = '-1.25*x*x*x+11.25*x*x-33.75*x+733.75'
  [../]
[]

[Variables]
  [./temp]
    order = FIRST
    family = LAGRANGE
    initial_condition = 700
  [../]
[]

[AuxVariables]
  [./hydro_constant]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./hydro_first]
    order = FIRST
    family = MONOMIAL
  [../]
  [./hydro_second]
    order = SECOND
    family = MONOMIAL
  [../]
  [./sxx_constant]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./sxx_first]
    order = FIRST
    family = MONOMIAL
  [../]
  [./sxx_second]
    order = SECOND
    family = MONOMIAL
  [../]
  [./szz_constant]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./szz_first]
    order = FIRST
    family = MONOMIAL
  [../]
  [./szz_second]
    order = SECOND
    family = MONOMIAL
  [../]
  [./temp2]
    order = FIRST
    family = LAGRANGE
    initial_condition = 700
  [../]
[]

[Modules]
  [./TensorMechanics]
    [./Master]
      [./all]
        add_variables = true
        strain = SMALL
        incremental = true
        temperature = temp2
        eigenstrain_names = 'reduced_eigenstrain' #'thermal_eigenstrain'
      [../]
    [../]
  [../]
[]

[Kernels]
  [./heat]
    type = Diffusion
    variable = temp
  [../]
[]

[AuxKernels]
  [./hydro_constant_aux]
    type = RankTwoScalarAux
    variable = hydro_constant
    rank_two_tensor = stress
    scalar_type = Hydrostatic
  [../]
  [./hydro_first_aux]
    type = RankTwoScalarAux
    variable = hydro_first
    rank_two_tensor = stress
    scalar_type = Hydrostatic
  [../]
  [./hydro_second_aux]
    type = RankTwoScalarAux
    variable = hydro_second
    rank_two_tensor = stress
    scalar_type = Hydrostatic
  [../]
  [./sxx_constant_aux]
    type = RankTwoAux
    variable = sxx_constant
    rank_two_tensor = stress
    index_i = 0
    index_j = 0
  [../]
  [./sxx_first_aux]
    type = RankTwoAux
    variable = sxx_first
    rank_two_tensor = stress
    index_i = 0
    index_j = 0
  [../]
  [./sxx_second_aux]
    type = RankTwoAux
    variable = sxx_second
    rank_two_tensor = stress
    index_i = 0
    index_j = 0
  [../]
  [./szz_constant_aux]
    type = RankTwoAux
    variable = szz_constant
    rank_two_tensor = stress
    index_i = 2
    index_j = 2
  [../]
  [./szz_first_aux]
    type = RankTwoAux
    variable = szz_first
    rank_two_tensor = stress
    index_i = 2
    index_j = 2
  [../]
  [./szz_second_aux]
    type = RankTwoAux
    variable = szz_second
    rank_two_tensor = stress
    index_i = 2
    index_j = 2
  [../]
  [./temp2]
    type = FunctionAux
    variable = temp2
    function = tempLinear
    execute_on = timestep_begin
  [../]
[]

[BCs]
  [./no_x]
    type = DirichletBC
    variable = disp_x
    boundary = left
    value = 0.0
  [../]
  [./no_y]
    type = DirichletBC
    variable = disp_y
    boundary = 'bottom top'
    value = 0.0
  [../]

  [./temp_right]
    type = DirichletBC
    variable = temp
    boundary = right
    value = 700
  [../]
  [./temp_left]
    type = DirichletBC
    variable = temp
    boundary = left
    value = 710
  [../]
[]


[Materials]
  [./fuel_stress]
    type = ComputeFiniteStrainElasticStress
  [../]
  [./elasticity_tensor]
    type = ComputeIsotropicElasticityTensor
    youngs_modulus = 1
    poissons_ratio = 0
  [../]
  [./fuel_thermal_expansion]
    type = ComputeThermalExpansionEigenstrain
    thermal_expansion_coeff = 1
    temperature = temp2
    stress_free_temperature = 700.0
    eigenstrain_name = 'thermal_eigenstrain'
  [../]
  [./reduced_order_eigenstrain]
    type = ComputeReducedOrderEigenstrain
    input_eigenstrain_names = 'thermal_eigenstrain'
    eigenstrain_name = 'reduced_eigenstrain'
  [../]
[]


[Preconditioning]
  [./SMP]
    type = SMP
    full = true
  [../]
[]

[Executioner]
  type = Transient
  solve_type = 'PJFNK'

  petsc_options = '-snes_ksp_ew '
  petsc_options_iname = '-ksp_gmres_restart -pc_type -pc_hypre_type'
  petsc_options_value = '70 hypre boomeramg'

  num_steps = 1
  nl_rel_tol = 1e-8 #1e-12
[]

[Postprocessors]
  [./_dt]
    type = TimestepSize
  [../]
[]

[VectorPostprocessors]
  [./hydro]
    type = LineValueSampler
    warn_discontinuous_face_values = false
    num_points = 100
    start_point = '1 0.07e-3 0'
    end_point = '3 0.07e-3 0'
    sort_by = x
    variable = 'hydro_constant hydro_first hydro_second temp2 disp_x disp_y'
  [../]
[]

[Outputs]
  exodus = true
  csv = true
[]