AD Abrupt Softening

Softening model with an abrupt stress release upon cracking. This class relies on automatic differentiation and is intended to be used with ADComputeSmearedCrackingStress.

Description

The material ADAbruptSoftening computes the reduced stress and stiffness in the direction of a crack according to a step function. The computed cracked stiffness ratio softens the tensile response of the material once the principle stress exceeds the cracking stress threshold of the material. It uses automatic differentiation for the computation of its Jacobian. For more details, refer to the non-AD version AbruptSoftening.

Example Input File

[./abrupt_softening]
  type = ADAbruptSoftening
[../]

ADAbruptSoftening must be run in conjunction with the fixed ad smeared cracking material model as shown below:

[./elastic_stress]
  type = ADComputeSmearedCrackingStress
  cracking_stress = 1.68e6
  cracked_elasticity_type = FULL
  softening_models = abrupt_softening
[../]

Input Parameters

blockThe list of blocks (ids or names) that this object will be applied
C++ Type:std::vector<SubdomainName>
Unit:(no unit assumed)
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>
Unit:(no unit assumed)
Controllable:No
Description:The list of boundaries (ids or names) from the mesh where this object applies
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
Unit:(no unit assumed)
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
Unit:(no unit assumed)
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
Unit:(no unit assumed)
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.
residual_stress0The fraction of the cracking stress allowed to be maintained following a crack.
Default:0
C++ Type:double
Unit:(no unit assumed)
Controllable:No
Description:The fraction of the cracking stress allowed to be maintained following a crack.
use_interpolated_stateFalseFor the old and older state use projected material properties interpolated at the quadrature points. To set up projection use the ProjectedStatefulMaterialStorageAction.
Default:False
C++ Type:bool
Unit:(no unit assumed)
Controllable:No
Description:For the old and older state use projected material properties interpolated at the quadrature points. To set up projection use the ProjectedStatefulMaterialStorageAction.

Optional Parameters

control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector<std::string>
Unit:(no unit assumed)
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
Unit:(no unit assumed)
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
Unit:(no unit assumed)
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
Unit:(no unit assumed)
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
Unit:(no unit assumed)
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>
Unit:(no unit assumed)
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>
Unit:(no unit assumed)
Controllable:No
Description:Vector of output names where you would like to restrict the output of variables(s) associated with this object

Outputs Parameters

References

No citations exist within this document.

(moose/modules/solid_mechanics/test/tests/ad_smeared_cracking/cracking_rz.i)

#

[Mesh]
  file = cracking_rz_test.e
[]

[Problem]
  coord_type = RZ
[]

[GlobalParams]
  displacements = 'disp_x disp_y'
[]

[Functions]
  [./displ]
    type = PiecewiseLinear
    x = '0 1 2 3  4'
    y = '0 1 0 -1 0'
  [../]
[]

[Physics/SolidMechanics/QuasiStatic]
  [./all]
    strain = FINITE
    add_variables = true
    generate_output = 'stress_xx stress_yy stress_zz stress_xy stress_yz stress_zx'
    use_automatic_differentiation = true
  [../]
[]

[BCs]
  [./pull]
    type = ADFunctionDirichletBC
    variable = disp_x
    boundary = 2
    function = displ
  [../]
  [./left]
    type = ADDirichletBC
    variable = disp_x
    boundary = 1
    value = 0.0
  [../]
  [./bottom]
    type = ADDirichletBC
    variable = disp_y
    boundary = 3
    value = 0.0
  [../]
[]

[Materials]
  [./elasticity_tensor]
    type = ADComputeIsotropicElasticityTensor
    youngs_modulus = 4.0e7
    poissons_ratio = 0.0
  [../]
  [./elastic_stress]
    type = ADComputeSmearedCrackingStress
    cracking_stress = 1.68e6
    cracked_elasticity_type = FULL
    softening_models = abrupt_softening
  [../]
  [./abrupt_softening]
    type = ADAbruptSoftening
  [../]
[]

[Executioner]
  type = Transient
  solve_type = Newton

  petsc_options_iname = '-ksp_gmres_restart'
  petsc_options_value = '101               '

  line_search = 'none'

  l_max_its = 100
  nl_max_its = 100
  nl_rel_tol = 1e-8
  nl_abs_tol = 1e-2
  l_tol = 1e-5
  start_time = 0.0
  end_time = 0.1
  dt = 0.025
[]

[Outputs]
  exodus = true
[]

(moose/modules/solid_mechanics/test/tests/ad_smeared_cracking/cracking_rz.i)

#

[Mesh]
  file = cracking_rz_test.e
[]

[Problem]
  coord_type = RZ
[]

[GlobalParams]
  displacements = 'disp_x disp_y'
[]

[Functions]
  [./displ]
    type = PiecewiseLinear
    x = '0 1 2 3  4'
    y = '0 1 0 -1 0'
  [../]
[]

[Physics/SolidMechanics/QuasiStatic]
  [./all]
    strain = FINITE
    add_variables = true
    generate_output = 'stress_xx stress_yy stress_zz stress_xy stress_yz stress_zx'
    use_automatic_differentiation = true
  [../]
[]

[BCs]
  [./pull]
    type = ADFunctionDirichletBC
    variable = disp_x
    boundary = 2
    function = displ
  [../]
  [./left]
    type = ADDirichletBC
    variable = disp_x
    boundary = 1
    value = 0.0
  [../]
  [./bottom]
    type = ADDirichletBC
    variable = disp_y
    boundary = 3
    value = 0.0
  [../]
[]

[Materials]
  [./elasticity_tensor]
    type = ADComputeIsotropicElasticityTensor
    youngs_modulus = 4.0e7
    poissons_ratio = 0.0
  [../]
  [./elastic_stress]
    type = ADComputeSmearedCrackingStress
    cracking_stress = 1.68e6
    cracked_elasticity_type = FULL
    softening_models = abrupt_softening
  [../]
  [./abrupt_softening]
    type = ADAbruptSoftening
  [../]
[]

[Executioner]
  type = Transient
  solve_type = Newton

  petsc_options_iname = '-ksp_gmres_restart'
  petsc_options_value = '101               '

  line_search = 'none'

  l_max_its = 100
  nl_max_its = 100
  nl_rel_tol = 1e-8
  nl_abs_tol = 1e-2
  l_tol = 1e-5
  start_time = 0.0
  end_time = 0.1
  dt = 0.025
[]

[Outputs]
  exodus = true
[]