Crack Front Data

Determines which nodes are along the crack front

Description

This object is a utility function used to output values of nodal variables at nodes along a crack front used in a fracture domain integral calculation. This is useful for tying information about solution variables to the computed fracture integrals at specific points. The definition of the crack points must be provided using a CrackFrontDefinition object, which is typically set up automatically using a DomainIntegralAction.

Example Input File Syntax

[./disp_x_centercrack]
  type = CrackFrontData
  crack_front_definition = crackFrontDefinition
  variable = disp_x
  crack_front_point_index = 1
[../]

Input Parameters

crack_front_definitionThe CrackFrontDefinition user object name
C++ Type:UserObjectName
Controllable:No
Description:The CrackFrontDefinition user object name
variableThe name of a variable whose value at the crack front is to be reported
C++ Type:VariableName
Controllable:No
Description:The name of a variable whose value at the crack front is to be reported

Required Parameters

crack_front_point_indexThe index of the point on the crack front where data is to be reported
C++ Type:unsigned int
Controllable:No
Description:The index of the point on the crack front where data is to be reported
execute_onTIMESTEP_ENDThe list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM, ALWAYS.
Default:TIMESTEP_END
C++ Type:ExecFlagEnum
Options:NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM, ALWAYS, TRANSFER
Controllable:No
Description:The list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM, ALWAYS.
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.
scale_factor1A scale factor to be applied to the reported quantity
Default:1
C++ Type:double
Controllable:No
Description:A scale factor to be applied to the reported quantity

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
Controllable:No
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<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.
execution_order_group0Execution order groups are executed in increasing order (e.g., the lowest number is executed first). Note that negative group numbers may be used to execute groups before the default (0) group. Please refer to the user object documentation for ordering of user object execution within a group.
Default:0
C++ Type:int
Controllable:No
Description:Execution order groups are executed in increasing order (e.g., the lowest number is executed first). Note that negative group numbers may be used to execute groups before the default (0) group. Please refer to the user object documentation for ordering of user object execution within a group.
force_postauxFalseForces the UserObject to be executed in POSTAUX
Default:False
C++ Type:bool
Controllable:No
Description:Forces the UserObject to be executed in POSTAUX
force_preauxFalseForces the UserObject to be executed in PREAUX
Default:False
C++ Type:bool
Controllable:No
Description:Forces the UserObject to be executed in PREAUX
force_preicFalseForces the UserObject to be executed in PREIC during initial setup
Default:False
C++ Type:bool
Controllable:No
Description:Forces the UserObject to be executed in PREIC during initial setup
outputsVector of output names where you would like to restrict the output of variables(s) associated with this object
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
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

(../moose/modules/tensor_mechanics/test/tests/j_integral/j_integral_3d.i)

#This tests the J-Integral evaluation capability.
#This is a 3d extrusion of a 2d plane strain model with 2 elements
#through the thickness, and calculates the J-Integrals using options
#to treat it as 3d.
#The analytic solution for J1 is 2.434.  This model
#converges to that solution with a refined mesh.
#Reference: National Agency for Finite Element Methods and Standards (U.K.):
#Test 1.1 from NAFEMS publication "Test Cases in Linear Elastic Fracture
#Mechanics" R0020.

[GlobalParams]
  order = FIRST
  family = LAGRANGE
  displacements = 'disp_x disp_y disp_z'
  volumetric_locking_correction = true
[]

[Mesh]
  file = crack3d.e
[]

[AuxVariables]
  [./SED]
    order = CONSTANT
    family = MONOMIAL
  [../]
[]

[Functions]
  [./rampConstant]
    type = PiecewiseLinear
    x = '0. 1.'
    y = '0. 1.'
    scale_factor = -1e2
  [../]
[]

[DomainIntegral]
  integrals = JIntegral
  boundary = 800
  crack_direction_method = CrackDirectionVector
  crack_direction_vector = '1 0 0'
  radius_inner = '4.0 5.5'
  radius_outer = '5.5 7.0'
  output_variable = 'disp_x'
  output_q = false
  incremental = true
  symmetry_plane = 1
[]

[Modules/TensorMechanics/Master]
  [./master]
    strain = FINITE
    add_variables = true
    incremental = true
    generate_output = 'stress_xx stress_yy stress_zz vonmises_stress'
  [../]
[]

[AuxKernels]
  [./SED]
    type = MaterialRealAux
    variable = SED
    property = strain_energy_density
    execute_on = timestep_end
  [../]
[]

[BCs]
  [./crack_y]
    type = DirichletBC
    variable = disp_y
    boundary = 100
    value = 0.0
  [../]
  [./no_z]
    type = DirichletBC
    variable = disp_z
    boundary = 500
    value = 0.0
  [../]
  [./no_z2]
    type = DirichletBC
    variable = disp_z
    boundary = 510
    value = 0.0
  [../]

  [./no_x]
    type = DirichletBC
    variable = disp_x
    boundary = 700
    value = 0.0
  [../]

  [./Pressure]
    [./Side1]
      boundary = 400
      function = rampConstant
    [../]
  [../]

[]

[Materials]
  [./elasticity_tensor]
    type = ComputeIsotropicElasticityTensor
    youngs_modulus = 207000
    poissons_ratio = 0.3
  [../]
  [./elastic_stress]
    type = ComputeFiniteStrainElasticStress
  [../]
[]


[Executioner]
  type = Transient

  petsc_options = '-snes_ksp_ew'
  petsc_options_iname = '-ksp_gmres_restart'
  petsc_options_value = '101'

  line_search = 'none'

  l_max_its = 50
  nl_max_its = 20
  nl_abs_tol = 1e-5
  l_tol = 1e-2

  start_time = 0.0
  dt = 1

  end_time = 1
  num_steps = 1
[]

[Postprocessors]
  [./disp_x_centercrack]
    type = CrackFrontData
    crack_front_definition = crackFrontDefinition
    variable = disp_x
    crack_front_point_index = 1
  [../]
[]

[Outputs]
  file_base = j_integral_3d_out
  exodus = true
  csv = true
[]