RANFSNormalMechanicalContact

Enforces the zero penetration constraint using the Reduced Active Nonlinear Function Set (RANFS) scheme. The algorithm is as follows: do a min comparison between the penetration and the Lagrange Multiplier (LM) associated with the zero penetration constraint. If the penetration (properly signed) is less than the LM, then we replace the non-linear residual equation for the slave node with the zero-penetration constraint equation (represented simply by the gap). In this way the gap is required to be zero.

Advantages of the RANFS scheme:

No Lagrange Multipliers, e.g. no saddle-point and consequently we are free to use preconditioners like AMG
No penalty term, so no introduction of ill conditioning into the matrix
Exact satisfaction of the constraints

The RANFSNormalMechanicalContact object includes ping-ponging protection. It detects when a slave node has alternated back and forth between two different element faces a sufficient number of times (currently face1-face2-face1-face2-face1) and then fixes the issue by applying more RANFS Explicitly, we apply a number of equality constraints equal to the mesh dimension tying together the locations of the slave node and the nearest master node (which we assert is a node that both master faces involved in the ping-pong share). This ping-ponging protection is necessary for solving step 19 of the full-bouncing-block-ranfs test. Without the protection the solve does not converge and the time-step gets cut.

/modules/contact/test/tests/bouncing-block-contact/bouncing-block-ranfs.i

starting_point = 2e-1
offset = 1e-2

[GlobalParams]
  displacements = 'disp_x disp_y'
  diffusivity = 1e0
[]

[Mesh]
  file = long-bottom-block-no-lower-d.e
[]

[Variables]
  [./disp_x]
  [../]
  [./disp_y]
  [../]
[]

[ICs]
  [./disp_y]
    block = 2
    variable = disp_y
    value = ${fparse starting_point + offset}
    type = ConstantIC
  [../]
[]

[Kernels]
  [./disp_x]
    type = MatDiffusion
    variable = disp_x
  [../]
  [./disp_y]
    type = MatDiffusion
    variable = disp_y
  [../]
[]


[Constraints]
  [./disp_x]
    type = RANFSNormalMechanicalContact
    slave = 10
    master = 20
    variable = disp_x
    master_variable = disp_x
    component = x
  [../]
  [./disp_y]
    type = RANFSNormalMechanicalContact
    slave = 10
    master = 20
    variable = disp_y
    master_variable = disp_y
    component = y
  [../]
[]

[BCs]
  [./botx]
    type = DirichletBC
    variable = disp_x
    boundary = 40
    value = 0.0
  [../]
  [./boty]
    type = DirichletBC
    variable = disp_y
    boundary = 40
    value = 0.0
  [../]
  [./topy]
    type = FunctionDirichletBC
    variable = disp_y
    boundary = 30
    function = '${starting_point} * cos(2 * pi / 40 * t) + ${offset}'
  [../]
  [./leftx]
    type = FunctionDirichletBC
    variable = disp_x
    boundary = 50
    function = '1e-2 * t'
  [../]
[]

[Executioner]
  type = Transient
  end_time = 200
  dt = 5
  dtmin = 5
  solve_type = 'PJFNK'
  petsc_options = '-snes_converged_reason -ksp_converged_reason'
  petsc_options_iname = '-pc_type -pc_hypre_type -mat_mffd_err'
  petsc_options_value = 'hypre    boomeramg      1e-5'
  l_max_its = 30
  nl_max_its = 20
  line_search = 'none'
[]

[Debug]
  show_var_residual_norms = true
[]

[Outputs]
  [exo]
    type = Exodus
  []
  checkpoint = true
[]

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

[Postprocessors]
  [./num_nl]
    type = NumNonlinearIterations
  [../]
  [./cumulative]
    type = CumulativeValuePostprocessor
    postprocessor = num_nl
  [../]
[]

Applies the Reduced Active Nonlinear Function Set scheme in which the slave node's non-linear residual function is replaced by the zero penetration constraint equation when the constraint is active

Input Parameters

componentThe force component constraint that this object is supplying
C++ Type:MooseEnum
Options:x y z
Description:The force component constraint that this object is supplying
displacementsThe displacements appropriate for the simulation geometry and coordinate system
C++ Type:std::vector
Options:
Description:The displacements appropriate for the simulation geometry and coordinate system
masterThe boundary ID associated with the master side
C++ Type:BoundaryName
Options:
Description:The boundary ID associated with the master side
master_variableThe variable on the master side of the domain
C++ Type:std::vector
Options:
Description:The variable on the master side of the domain
slaveThe boundary ID associated with the slave side
C++ Type:BoundaryName
Options:
Description:The boundary ID associated with the slave side
variableThe name of the variable that this constraint is applied to.
C++ Type:NonlinearVariableName
Options:
Description:The name of the variable that this constraint is applied to.

Required Parameters

execute_onLINEARThe list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM.
Default:LINEAR
C++ Type:ExecFlagEnum
Options:NONE INITIAL LINEAR NONLINEAR TIMESTEP_END TIMESTEP_BEGIN FINAL CUSTOM
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, FINAL, CUSTOM.
normal_smoothing_distanceDistance from edge in parametric coordinates over which to smooth contact normal
C++ Type:double
Options:
Description:Distance from edge in parametric coordinates over which to smooth contact normal
normal_smoothing_methodMethod to use to smooth normals (edge_based|nodal_normal_based)
C++ Type:std::string
Options:
Description:Method to use to smooth normals (edge_based|nodal_normal_based)
orderFIRSTThe finite element order used for projections
Default:FIRST
C++ Type:MooseEnum
Options:FIRST SECOND THIRD FOURTH
Description:The finite element order used for projections
tangential_toleranceTangential distance to extend edges of contact surfaces
C++ Type:double
Options:
Description:Tangential distance to extend edges of contact surfaces

Optional Parameters

control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector
Options:
Description:Adds user-defined labels for accessing object parameters via control logic.
enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Options:
Description:Set the enabled status of the MooseObject.
use_displaced_meshTrueWhether 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:True
C++ Type:bool
Options:
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

extra_matrix_tagsThe extra tags for the matrices this Kernel should fill
C++ Type:std::vector
Options:
Description:The extra tags for the matrices this Kernel should fill
extra_vector_tagsThe extra tags for the vectors this Kernel should fill
C++ Type:std::vector
Options:
Description:The extra tags for the vectors this Kernel should fill
matrix_tagssystemThe tag for the matrices this Kernel should fill
Default:system
C++ Type:MultiMooseEnum
Options:nontime system
Description:The tag for the matrices this Kernel should fill
vector_tagsnontimeThe tag for the vectors this Kernel should fill
Default:nontime
C++ Type:MultiMooseEnum
Options:nontime time
Description:The tag for the vectors this Kernel should fill

Tagging Parameters

Input Files

modules/contact/test/tests/bouncing-block-contact/bouncing-block-ranfs.i
modules/contact/test/tests/bouncing-block-contact/frictionless-nodal-reduced-active-set.i

modules/contact/test/tests/bouncing-block-contact/bouncing-block-ranfs.i

starting_point = 2e-1
offset = 1e-2

[GlobalParams]
  displacements = 'disp_x disp_y'
  diffusivity = 1e0
[]

[Mesh]
  file = long-bottom-block-no-lower-d.e
[]

[Variables]
  [./disp_x]
  [../]
  [./disp_y]
  [../]
[]

[ICs]
  [./disp_y]
    block = 2
    variable = disp_y
    value = ${fparse starting_point + offset}
    type = ConstantIC
  [../]
[]

[Kernels]
  [./disp_x]
    type = MatDiffusion
    variable = disp_x
  [../]
  [./disp_y]
    type = MatDiffusion
    variable = disp_y
  [../]
[]


[Constraints]
  [./disp_x]
    type = RANFSNormalMechanicalContact
    slave = 10
    master = 20
    variable = disp_x
    master_variable = disp_x
    component = x
  [../]
  [./disp_y]
    type = RANFSNormalMechanicalContact
    slave = 10
    master = 20
    variable = disp_y
    master_variable = disp_y
    component = y
  [../]
[]

[BCs]
  [./botx]
    type = DirichletBC
    variable = disp_x
    boundary = 40
    value = 0.0
  [../]
  [./boty]
    type = DirichletBC
    variable = disp_y
    boundary = 40
    value = 0.0
  [../]
  [./topy]
    type = FunctionDirichletBC
    variable = disp_y
    boundary = 30
    function = '${starting_point} * cos(2 * pi / 40 * t) + ${offset}'
  [../]
  [./leftx]
    type = FunctionDirichletBC
    variable = disp_x
    boundary = 50
    function = '1e-2 * t'
  [../]
[]

[Executioner]
  type = Transient
  end_time = 200
  dt = 5
  dtmin = 5
  solve_type = 'PJFNK'
  petsc_options = '-snes_converged_reason -ksp_converged_reason'
  petsc_options_iname = '-pc_type -pc_hypre_type -mat_mffd_err'
  petsc_options_value = 'hypre    boomeramg      1e-5'
  l_max_its = 30
  nl_max_its = 20
  line_search = 'none'
[]

[Debug]
  show_var_residual_norms = true
[]

[Outputs]
  [exo]
    type = Exodus
  []
  checkpoint = true
[]

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

[Postprocessors]
  [./num_nl]
    type = NumNonlinearIterations
  [../]
  [./cumulative]
    type = CumulativeValuePostprocessor
    postprocessor = num_nl
  [../]
[]

modules/contact/test/tests/bouncing-block-contact/frictionless-nodal-reduced-active-set.i

starting_point = .5

[GlobalParams]
  displacements = 'disp_x disp_y'
  diffusivity = 1
[]

[Mesh]
  file = square-blocks-no-offset.e
[]

[Variables]
  [./disp_x]
  [../]
  [./disp_y]
  [../]
[]

[ICs]
  [./disp_y]
    block = 2
    variable = disp_y
    value = ${starting_point}
    type = ConstantIC
  [../]
[]

[Kernels]
  [./disp_x]
    type = MatDiffusion
    variable = disp_x
  [../]
  [./disp_y]
    type = MatDiffusion
    variable = disp_y
  [../]
[]


[Constraints]
  [./disp_x]
    type = RANFSNormalMechanicalContact
    slave = 10
    master = 20
    variable = disp_x
    master_variable = disp_x
    component = x
  [../]
  [./disp_y]
    type = RANFSNormalMechanicalContact
    slave = 10
    master = 20
    variable = disp_y
    master_variable = disp_y
    component = y
  [../]
[]

[BCs]
  [./botx]
    type = DirichletBC
    variable = disp_x
    preset = false
    boundary = 40
    value = 0.0
  [../]
  [./topx]
    type = DirichletBC
    variable = disp_x
    preset = false
    boundary = 30
    value = 0.0
  [../]
  [./boty]
    type = DirichletBC
    variable = disp_y
    preset = false
    boundary = 40
    value = 0.0
  [../]
  [./topy]
    type = FunctionDirichletBC
    variable = disp_y
    preset = false
    boundary = 30
    function = '${starting_point} - t'
  [../]
[]

[Executioner]
  type = Transient
  num_steps = 1
  dt = 1
  dtmin = 1
  solve_type = 'PJFNK'
  petsc_options = '-snes_converged_reason -ksp_converged_reason -ksp_monitor_true_residual -snes_view'
  petsc_options_iname = '-mat_mffd_err -pc_type -pc_hypre_type'
  petsc_options_value = '1e-5          hypre    boomeramg'
  l_max_its = 30
  nl_max_its = 20
  line_search = 'project'
[]

[Debug]
  show_var_residual_norms = true
[]

[Outputs]
  [exo]
    type = Exodus
    execute_on = 'nonlinear'
  []
  print_linear_residuals = false
  [dof]
    type = DOFMap
    execute_on = 'initial'
  []
[]

[Postprocessors]
  [./num_nl]
    type = NumNonlinearIterations
  [../]
  [./cumulative]
    type = CumulativeValuePostprocessor
    postprocessor = num_nl
  [../]
[]

References

Input Parameters
Input Files
References

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Physics and Syntax

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