MeshCut2DFunctionUserObject

Creates a UserObject for a mesh cutter in 2D problems where crack growth is specified by functions.

Overview

This class is used to define an evolving cutting plane for 2D XFEM simulations based on a mesh that defines an initial crack, and a user-defined function for growth of that crack. It (1) reads in a mesh describing the crack surface, (2) uses the mesh to do initial cutting of 2D elements, and (3) grows the mesh incrementally based on prescribed growth functions defining the direction and growth rate.

Example Input Syntax

[UserObjects]
  [./cut_mesh]
    type = MeshCut2DFunctionUserObject
    mesh_file = 2D_edge_crack.e
    growth_direction_x = growth_func_x
    growth_direction_y = growth_func_y
    growth_rate = growth_func_v
  [../]
[]

Input Parameters

growth_direction_xFunction defining x-component of crack growth direction.
C++ Type:FunctionName
Controllable:No
Description:Function defining x-component of crack growth direction.
growth_direction_yFunction defining y-component of crack growth direction.
C++ Type:FunctionName
Controllable:No
Description:Function defining y-component of crack growth direction.
growth_rateFunction defining crack growth rate.
C++ Type:FunctionName
Controllable:No
Description:Function defining crack growth rate.
mesh_fileMesh file for the XFEM geometric cut; currently only the Exodus type is supported
C++ Type:MeshFileName
Controllable:No
Description:Mesh file for the XFEM geometric cut; currently only the Exodus type is supported

Required Parameters

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
execute_onXFEM_MARKThe list of flag(s) indicating when this object should be executed, the available options include FORWARD, ADJOINT, HOMOGENEOUS_FORWARD, ADJOINT_TIMESTEP_BEGIN, ADJOINT_TIMESTEP_END, XFEM_MARK, NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM, ALWAYS.
Default:XFEM_MARK
C++ Type:ExecFlagEnum
Options:FORWARD, ADJOINT, HOMOGENEOUS_FORWARD, ADJOINT_TIMESTEP_BEGIN, ADJOINT_TIMESTEP_END, XFEM_MARK, NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM, ALWAYS
Controllable:No
Description:The list of flag(s) indicating when this object should be executed, the available options include FORWARD, ADJOINT, HOMOGENEOUS_FORWARD, ADJOINT_TIMESTEP_BEGIN, ADJOINT_TIMESTEP_END, XFEM_MARK, NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM, ALWAYS.
heal_alwaysFalseHeal previous cuts at every time step
Default:False
C++ Type:bool
Controllable:No
Description:Heal previous cuts at every time step
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

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
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

Input Files

(modules/xfem/test/tests/solid_mechanics_basic/edge_crack_2d_propagation.i)

(modules/xfem/test/tests/solid_mechanics_basic/edge_crack_2d_propagation.i)

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

[XFEM]
  geometric_cut_userobjects = 'cut_mesh'
  qrule = volfrac
  output_cut_plane = true
[]

[Mesh]
[block]
  type = GeneratedMeshGenerator
  dim = 2
  nx = 5
  ny = 5
  xmin = 0.0
  xmax = 1.0
  ymin = 0.0
  ymax = 1.0
  elem_type = QUAD4
[]
[]

[UserObjects]
  [./cut_mesh]
    type = MeshCut2DFunctionUserObject
    mesh_file = 2D_edge_crack.e
    growth_direction_x = growth_func_x
    growth_direction_y = growth_func_y
    growth_rate = growth_func_v
  [../]
[]

[Functions]
  [./growth_func_x]
    type = ParsedFunction
    expression = 0.4*t
  [../]
  [./growth_func_y]
    type = ParsedFunction
    expression = 1.8*(t-1)
  [../]
  [./growth_func_v]
    type = ParsedFunction
    expression = 0.1*t
  [../]
[]

[Modules/TensorMechanics/Master]
  [./all]
    strain = FINITE
    planar_formulation = plane_strain
    add_variables = true
    generate_output = 'stress_xx stress_yy vonmises_stress'
  [../]
[]

[Functions]
  [./top_trac_y]
    type = ConstantFunction
    value = 10
  [../]
[]


[BCs]
  [./top_y]
    type = FunctionNeumannBC
    boundary = top
    variable = disp_y
    function = top_trac_y
  [../]
  [./bottom_x]
    type = DirichletBC
    boundary = bottom
    variable = disp_x
    value = 0.0
  [../]
  [./bottom_y]
    type = DirichletBC
    boundary = bottom
    variable = disp_y
    value = 0.0
  [../]
[]

[Materials]
  [./elasticity_tensor]
    type = ComputeIsotropicElasticityTensor
    youngs_modulus = 207000
    poissons_ratio = 0.3
    block = 0
  [../]
  [./stress]
    type = ComputeFiniteStrainElasticStress
    block = 0
  [../]
[]

[Executioner]
  type = Transient

  solve_type = 'PJFNK'
  petsc_options_iname = '-ksp_gmres_restart -pc_type -pc_hypre_type -pc_hypre_boomeramg_max_iter'
  petsc_options_value = '201                hypre    boomeramg      8'

  line_search = 'none'

  [./Predictor]
    type = SimplePredictor
    scale = 1.0
  [../]

# controls for linear iterations
  l_max_its = 100
  l_tol = 1e-2

# controls for nonlinear iterations
  nl_max_its = 15
  nl_rel_tol = 1e-12
  nl_abs_tol = 1e-10

# time control
  start_time = 0.0
  dt = 1.0
  end_time = 2.0
  max_xfem_update = 2
[]

[Outputs]
  exodus = true
  execute_on = TIMESTEP_END
  [xfemcutter]
    type=XFEMCutMeshOutput
    xfem_cutter_uo=cut_mesh

  []
  [./console]
    type = Console
    output_linear = true
  [../]
[]

(modules/xfem/test/tests/solid_mechanics_basic/edge_crack_2d_propagation.i)

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

[XFEM]
  geometric_cut_userobjects = 'cut_mesh'
  qrule = volfrac
  output_cut_plane = true
[]

[Mesh]
[block]
  type = GeneratedMeshGenerator
  dim = 2
  nx = 5
  ny = 5
  xmin = 0.0
  xmax = 1.0
  ymin = 0.0
  ymax = 1.0
  elem_type = QUAD4
[]
[]

[UserObjects]
  [./cut_mesh]
    type = MeshCut2DFunctionUserObject
    mesh_file = 2D_edge_crack.e
    growth_direction_x = growth_func_x
    growth_direction_y = growth_func_y
    growth_rate = growth_func_v
  [../]
[]

[Functions]
  [./growth_func_x]
    type = ParsedFunction
    expression = 0.4*t
  [../]
  [./growth_func_y]
    type = ParsedFunction
    expression = 1.8*(t-1)
  [../]
  [./growth_func_v]
    type = ParsedFunction
    expression = 0.1*t
  [../]
[]

[Modules/TensorMechanics/Master]
  [./all]
    strain = FINITE
    planar_formulation = plane_strain
    add_variables = true
    generate_output = 'stress_xx stress_yy vonmises_stress'
  [../]
[]

[Functions]
  [./top_trac_y]
    type = ConstantFunction
    value = 10
  [../]
[]


[BCs]
  [./top_y]
    type = FunctionNeumannBC
    boundary = top
    variable = disp_y
    function = top_trac_y
  [../]
  [./bottom_x]
    type = DirichletBC
    boundary = bottom
    variable = disp_x
    value = 0.0
  [../]
  [./bottom_y]
    type = DirichletBC
    boundary = bottom
    variable = disp_y
    value = 0.0
  [../]
[]

[Materials]
  [./elasticity_tensor]
    type = ComputeIsotropicElasticityTensor
    youngs_modulus = 207000
    poissons_ratio = 0.3
    block = 0
  [../]
  [./stress]
    type = ComputeFiniteStrainElasticStress
    block = 0
  [../]
[]

[Executioner]
  type = Transient

  solve_type = 'PJFNK'
  petsc_options_iname = '-ksp_gmres_restart -pc_type -pc_hypre_type -pc_hypre_boomeramg_max_iter'
  petsc_options_value = '201                hypre    boomeramg      8'

  line_search = 'none'

  [./Predictor]
    type = SimplePredictor
    scale = 1.0
  [../]

# controls for linear iterations
  l_max_its = 100
  l_tol = 1e-2

# controls for nonlinear iterations
  nl_max_its = 15
  nl_rel_tol = 1e-12
  nl_abs_tol = 1e-10

# time control
  start_time = 0.0
  dt = 1.0
  end_time = 2.0
  max_xfem_update = 2
[]

[Outputs]
  exodus = true
  execute_on = TIMESTEP_END
  [xfemcutter]
    type=XFEMCutMeshOutput
    xfem_cutter_uo=cut_mesh

  []
  [./console]
    type = Console
    output_linear = true
  [../]
[]

Overview
Example Input Syntax
Input Parameters
Input Files