ElementJacobianDamper

Damper that limits the change in element Jacobians

This damper limits the change in the Jacobians of elements. The damper becomes active if the relative change in Jacobian of any element exceeds the user defined maximum. This damper must be run on the displaced mesh.

Input Parameters

displacementsThe nonlinear displacement variables
C++ Type:std::vector<VariableName>
Controllable:No
Description:The nonlinear displacement variables
max_increment0.1The maximum permissible relative increment in the Jacobian per Newton iteration
Default:0.1
C++ Type:double
Controllable:No
Description:The maximum permissible relative increment in the Jacobian per Newton iteration
min_damping0Minimum value of computed damping. Damping lower than this will result in an exception being thrown and cutting the time step
Default:0
C++ Type:double
Controllable:No
Description:Minimum value of computed damping. Damping lower than this will result in an exception being thrown and cutting the time step
use_displaced_meshTrue
Default:True
C++ Type:bool
Controllable:No

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.

Advanced Parameters

Input Files

(modules/solid_mechanics/test/tests/jacobian_damper/cube_load.i)

(modules/solid_mechanics/test/tests/jacobian_damper/cube_load.i)

[Mesh]
  type = GeneratedMesh
  dim = 3
  nx = 1
  ny = 1
  nz = 1
  displacements = 'disp_x disp_y disp_z'
  # This test uses ElementalVariableValue postprocessors on specific
  # elements, so element numbering needs to stay unchanged
  allow_renumbering = false
[]

[Variables]
  [./disp_x]
    order = FIRST
    family = LAGRANGE
  [../]

  [./disp_y]
    order = FIRST
    family = LAGRANGE
  [../]

  [./disp_z]
    order = FIRST
    family = LAGRANGE
  [../]
[]

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

  [./total_strain_yy]
    order = CONSTANT
    family = MONOMIAL
  [../]
[]

[Functions]
  [./top_pull]
    type = PiecewiseLinear
    x = '0 1     2'
    y = '0 0.025 0.05'
  [../]
[]

[Kernels]
  [SolidMechanics]
    displacements = 'disp_x disp_y disp_z'
    use_displaced_mesh = true
  [../]
[]

[AuxKernels]
  [./stress_yy]
    type = RankTwoAux
    rank_two_tensor = stress
    variable = stress_yy
    index_i = 1
    index_j = 1
  [../]

  [./total_strain_yy]
    type = RankTwoAux
    rank_two_tensor = total_strain
    variable = total_strain_yy
    index_i = 1
    index_j = 1
  [../]
[]


[BCs]
  [./y_pull_function]
    type = FunctionDirichletBC
    variable = disp_y
    boundary = 3
    function = top_pull
  [../]

  [./x_bot]
    type = DirichletBC
    variable = disp_x
    boundary = 4
    value = 0.0
  [../]

  [./y_bot]
    type = DirichletBC
    variable = disp_y
    boundary = 1
    value = 0.0
  [../]

  [./z_bot]
    type = DirichletBC
    variable = disp_z
    boundary = 0
    value = 0.0
  [../]
[]

[Postprocessors]
  [./stress_yy_el]
    type = ElementalVariableValue
    variable = stress_yy
    elementid = 0
  [../]
[]

[Materials]
  [./elasticity_tensor]
    type = ComputeIsotropicElasticityTensor
    poissons_ratio = 0.3
    youngs_modulus = 2e5
  [../]
  [./strain]
    type = ComputeFiniteStrain
    displacements = 'disp_x disp_y disp_z'
  [../]
  [./stress]
    type = ComputeFiniteStrainElasticStress
  [../]
[]

[Dampers]
  [./disp_x_damp]
    type = ElementJacobianDamper
    max_increment = 0.002
    displacements = 'disp_x disp_y disp_z'
  [../]
[]

[Executioner]
  type = Transient

  #Preconditioned JFNK (default)
  solve_type = 'PJFNK'

  petsc_options = '-snes_ksp_ew'
  petsc_options_iname = '-ksp_gmres_restart -pc_type -pc_hypre_type -pc_hypre_boomeramg_max_iter'
  petsc_options_value = '201                hypre    boomeramg      4'

  line_search = 'none'

  l_max_its = 100
  nl_max_its = 100
  nl_rel_tol = 1e-12
  nl_abs_tol = 1e-10
  l_tol = 1e-9

  start_time = 0.0
  end_time = 2
  dt = 1
[]

[Outputs]
  exodus = true
[]

Input Parameters
Input Files