MortarContactForce

Overview

MortarContactForce reports the normal contact force that one mortar contact pair transmits to its secondary surface. It reads the pair's weighted gap user object, so each pair of a Contact block with several pairs can be reported without a separate residual tag per pair.

With the nodal contact pressures $var element = document.getElementById("moose-equation-48acfece-e064-462f-ab3d-a38b49defe69");katex.render("\\lambda_j", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ and nodal normals $var element = document.getElementById("moose-equation-adc7fab3-412b-4cda-8709-2332c2b56722");katex.render("\\mathbf{n}_j", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ of the secondary surface $var element = document.getElementById("moose-equation-2f6c40f7-6762-4b80-9f28-779e3c453925");katex.render("\\gamma_c^{(1)}", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ , the force is

$var element = document.getElementById("moose-equation-dd8a4b3f-fab9-44f1-8388-c66d4167ea4e");katex.render("\\mathbf{F} = \\sum_j \\lambda_j \\mathbf{n}_j \\int_{\\gamma_c^{(1)}} N_j \\, dA,", element, {displayMode:true,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$

where $var element = document.getElementById("moose-equation-0db6a7ba-8cd1-49e1-86fe-4ba4ef29fd98");katex.render("N_j", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ are the standard Lagrange shape functions and the integrals are taken over the mortar segments. This is the integral of the contact traction for the standard, dual and Petrov-Galerkin bases, since a dual basis function $var element = document.getElementById("moose-equation-d697aa94-f97f-473c-815b-fda2752930c3");katex.render("\\Phi_j", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ has the same integral as $var element = document.getElementById("moose-equation-6fff7171-99a5-4e0f-a989-9932a3f4afa7");katex.render("N_j", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ . The pressures $var element = document.getElementById("moose-equation-9b65e73a-c424-4bb3-89eb-77ed4a325cf1");katex.render("\\lambda_j", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ are the physical pressures, also under node-based scaling of the Lagrange multipliers.

The force is normal only; with friction, magnitude does not include the tangential force.

The "weighted_gap_uo" created by the Contact action is named lm_weightedgap_object_<block name> for the mortar formulation and penalty_weightedgap_object_<block name> for mortar_penalty, followed by _p_<primary>_s_<secondary> when the block has several pairs.

Example Input File Syntax

[Postprocessors<<<{"href": "../../syntax/Postprocessors/index.html"}>>>]
  [left_bottom_force]
    type = MortarContactForce<<<{"description": "Normal contact force that one mortar contact pair transmits to its secondary surface.", "href": "MortarContactForce.html"}>>>
    weighted_gap_uo<<<{"description": "The weighted gap user object of the contact pair. The Contact action names it lm_weightedgap_object_<block name> (mortar) or penalty_weightedgap_object_<block name> (mortar_penalty), with the suffix _p_<primary>_s_<secondary> when the block has several pairs."}>>> = lm_weightedgap_object_mortar_p_base_top_s_left_bottom
    component<<<{"description": "The force component to report, or its magnitude."}>>> = y
  []
  [right_bottom_force]
    type = MortarContactForce<<<{"description": "Normal contact force that one mortar contact pair transmits to its secondary surface.", "href": "MortarContactForce.html"}>>>
    weighted_gap_uo<<<{"description": "The weighted gap user object of the contact pair. The Contact action names it lm_weightedgap_object_<block name> (mortar) or penalty_weightedgap_object_<block name> (mortar_penalty), with the suffix _p_<primary>_s_<secondary> when the block has several pairs."}>>> = lm_weightedgap_object_mortar_p_base_top_s_right_bottom
    component<<<{"description": "The force component to report, or its magnitude."}>>> = y
  []
  [left_bottom_force_magnitude]
    type = MortarContactForce<<<{"description": "Normal contact force that one mortar contact pair transmits to its secondary surface.", "href": "MortarContactForce.html"}>>>
    weighted_gap_uo<<<{"description": "The weighted gap user object of the contact pair. The Contact action names it lm_weightedgap_object_<block name> (mortar) or penalty_weightedgap_object_<block name> (mortar_penalty), with the suffix _p_<primary>_s_<secondary> when the block has several pairs."}>>> = lm_weightedgap_object_mortar_p_base_top_s_left_bottom
  []
  [left_bottom_nodal_sum]
    type = NodalSum<<<{"description": "Computes the sum of all of the nodal values of the specified variable. Note: This object sets the default \"unique_node_execute\" flag to true to avoid double counting nodes between shared blocks.", "href": "NodalSum.html"}>>>
    variable<<<{"description": "The name of the variable that this postprocessor operates on"}>>> = contact_force_y
    boundary<<<{"description": "The list of boundaries (ids or names) from the mesh where this object applies"}>>> = left_bottom
  []
  [right_bottom_nodal_sum]
    type = NodalSum<<<{"description": "Computes the sum of all of the nodal values of the specified variable. Note: This object sets the default \"unique_node_execute\" flag to true to avoid double counting nodes between shared blocks.", "href": "NodalSum.html"}>>>
    variable<<<{"description": "The name of the variable that this postprocessor operates on"}>>> = contact_force_y
    boundary<<<{"description": "The list of boundaries (ids or names) from the mesh where this object applies"}>>> = right_bottom
  []
[]

Input Parameters

weighted_gap_uoThe weighted gap user object of the contact pair. The Contact action names it lm_weightedgap_object_ (mortar) or penalty_weightedgap_object_ (mortar_penalty), with the suffix _p__s_ when the block has several pairs.
C++ Type:UserObjectName
Controllable:No
Description:The weighted gap user object of the contact pair. The Contact action names it lm_weightedgap_object_ (mortar) or penalty_weightedgap_object_ (mortar_penalty), with the suffix _p__s_ when the block has several pairs.

Required Parameters

componentmagnitudeThe force component to report, or its magnitude.
Default:magnitude
C++ Type:MooseEnum
Options:x, y, z, magnitude
Controllable:No
Description:The force component to report, or its magnitude.

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).
execute_onTIMESTEP_ENDThe list of flag(s) indicating when this object should be executed. For a description of each flag, see https://mooseframework.inl.gov/source/interfaces/SetupInterface.html.
Default:TIMESTEP_END
C++ Type:ExecFlagEnum
Options:XFEM_MARK, FORWARD, ADJOINT, HOMOGENEOUS_FORWARD, ADJOINT_TIMESTEP_BEGIN, ADJOINT_TIMESTEP_END, NONE, INITIAL, LINEAR, LINEAR_CONVERGENCE, NONLINEAR, NONLINEAR_CONVERGENCE, POSTCHECK, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, MULTIAPP_FIXED_POINT_CONVERGENCE, MULTISYSTEM_FIXED_POINT_ITERATION_END, FINAL, CUSTOM, TRANSFER
Controllable:No
Description:The list of flag(s) indicating when this object should be executed. For a description of each flag, see https://mooseframework.inl.gov/source/interfaces/SetupInterface.html.
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

Execution Scheduling 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.
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

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.
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
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.

Material Property Retrieval Parameters

Input Files

(modules/contact/test/tests/mortar_contact_force/mortar_contact_force.i)

(modules/contact/test/tests/mortar_contact_force/mortar_contact_force.i)

# Two tall blocks on a wider bottom block, with all three contact pairs in one Contact block. The
# force of each bottom pair is compared with the nodal sum of the contact residual on its secondary
# surface. The two bottom pairs share the primary surface base_top.

[GlobalParams]
  displacements = 'disp_x disp_y'
[]

[Mesh]
  [bottom_block]
    type = GeneratedMeshGenerator
    dim = 2
    xmax = 2
    ymax = 1
    nx = 5
    ny = 2
    subdomain_ids = 1
    boundary_name_prefix = base
    boundary_id_offset = 10
  []
  [left_block]
    type = GeneratedMeshGenerator
    dim = 2
    xmax = 1
    ymin = 1
    ymax = 3
    nx = 3
    ny = 4
    subdomain_ids = 2
    boundary_name_prefix = left
    boundary_id_offset = 20
  []
  [right_block]
    type = GeneratedMeshGenerator
    dim = 2
    xmin = 1
    xmax = 2
    ymin = 1
    ymax = 3
    nx = 2
    ny = 3
    subdomain_ids = 3
    boundary_name_prefix = right
    boundary_id_offset = 30
  []
  [combine]
    type = CombinerGenerator
    inputs = 'bottom_block left_block right_block'
  []
[]

[Problem]
  extra_tag_vectors = 'contact_force'
[]

[Physics/SolidMechanics/QuasiStatic]
  [all]
    add_variables = true
    strain = SMALL
    block = '1 2 3'
  []
[]

[Materials]
  [elasticity]
    type = ComputeIsotropicElasticityTensor
    block = '1 2 3'
    youngs_modulus = 1e6
    poissons_ratio = 0.3
  []
  [stress]
    type = ComputeLinearElasticStress
    block = '1 2 3'
  []
[]

[Contact]
  active = 'mortar'
  [mortar]
    primary = 'base_top base_top right_left'
    secondary = 'left_bottom right_bottom left_right'
    model = frictionless
    formulation = mortar
    correct_edge_dropping = true
    extra_vector_tags = 'contact_force'
  []
  [penalty]
    primary = 'base_top base_top right_left'
    secondary = 'left_bottom right_bottom left_right'
    model = frictionless
    formulation = mortar_penalty
    penalty = 1e7
    extra_vector_tags = 'contact_force'
  []
[]

[BCs]
  [bottom_x]
    type = DirichletBC
    variable = disp_x
    boundary = base_bottom
    value = 0
  []
  [bottom_y]
    type = DirichletBC
    variable = disp_y
    boundary = base_bottom
    value = 0
  []
  [confine_left]
    type = DirichletBC
    variable = disp_x
    boundary = left_left
    value = 0
  []
  [confine_right]
    type = DirichletBC
    variable = disp_x
    boundary = right_right
    value = 0
  []
  [push_down]
    type = FunctionDirichletBC
    variable = disp_y
    boundary = 'left_top right_top'
    function = '-1e-3 * t'
  []
[]

[AuxVariables]
  [contact_force_y]
    block = '1 2 3'
  []
[]

[AuxKernels]
  [contact_force_y]
    type = TagVectorAux
    variable = contact_force_y
    v = disp_y
    vector_tag = contact_force
    block = '1 2 3'
  []
[]

[Postprocessors]
  [left_bottom_force]
    type = MortarContactForce
    weighted_gap_uo = lm_weightedgap_object_mortar_p_base_top_s_left_bottom
    component = y
  []
  [right_bottom_force]
    type = MortarContactForce
    weighted_gap_uo = lm_weightedgap_object_mortar_p_base_top_s_right_bottom
    component = y
  []
  [left_bottom_force_magnitude]
    type = MortarContactForce
    weighted_gap_uo = lm_weightedgap_object_mortar_p_base_top_s_left_bottom
  []
  [left_bottom_nodal_sum]
    type = NodalSum
    variable = contact_force_y
    boundary = left_bottom
  []
  [right_bottom_nodal_sum]
    type = NodalSum
    variable = contact_force_y
    boundary = right_bottom
  []
[]

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

[Executioner]
  type = Transient
  solve_type = NEWTON
  petsc_options_iname = '-pc_type -pc_factor_shift_type'
  petsc_options_value = 'lu       NONZERO'
  dt = 1
  end_time = 2
  nl_abs_tol = 1e-10
[]

[Outputs]
  csv = true
[]

(modules/contact/test/tests/mortar_contact_force/mortar_contact_force.i)

# Two tall blocks on a wider bottom block, with all three contact pairs in one Contact block. The
# force of each bottom pair is compared with the nodal sum of the contact residual on its secondary
# surface. The two bottom pairs share the primary surface base_top.

[GlobalParams]
  displacements = 'disp_x disp_y'
[]

[Mesh]
  [bottom_block]
    type = GeneratedMeshGenerator
    dim = 2
    xmax = 2
    ymax = 1
    nx = 5
    ny = 2
    subdomain_ids = 1
    boundary_name_prefix = base
    boundary_id_offset = 10
  []
  [left_block]
    type = GeneratedMeshGenerator
    dim = 2
    xmax = 1
    ymin = 1
    ymax = 3
    nx = 3
    ny = 4
    subdomain_ids = 2
    boundary_name_prefix = left
    boundary_id_offset = 20
  []
  [right_block]
    type = GeneratedMeshGenerator
    dim = 2
    xmin = 1
    xmax = 2
    ymin = 1
    ymax = 3
    nx = 2
    ny = 3
    subdomain_ids = 3
    boundary_name_prefix = right
    boundary_id_offset = 30
  []
  [combine]
    type = CombinerGenerator
    inputs = 'bottom_block left_block right_block'
  []
[]

[Problem]
  extra_tag_vectors = 'contact_force'
[]

[Physics/SolidMechanics/QuasiStatic]
  [all]
    add_variables = true
    strain = SMALL
    block = '1 2 3'
  []
[]

[Materials]
  [elasticity]
    type = ComputeIsotropicElasticityTensor
    block = '1 2 3'
    youngs_modulus = 1e6
    poissons_ratio = 0.3
  []
  [stress]
    type = ComputeLinearElasticStress
    block = '1 2 3'
  []
[]

[Contact]
  active = 'mortar'
  [mortar]
    primary = 'base_top base_top right_left'
    secondary = 'left_bottom right_bottom left_right'
    model = frictionless
    formulation = mortar
    correct_edge_dropping = true
    extra_vector_tags = 'contact_force'
  []
  [penalty]
    primary = 'base_top base_top right_left'
    secondary = 'left_bottom right_bottom left_right'
    model = frictionless
    formulation = mortar_penalty
    penalty = 1e7
    extra_vector_tags = 'contact_force'
  []
[]

[BCs]
  [bottom_x]
    type = DirichletBC
    variable = disp_x
    boundary = base_bottom
    value = 0
  []
  [bottom_y]
    type = DirichletBC
    variable = disp_y
    boundary = base_bottom
    value = 0
  []
  [confine_left]
    type = DirichletBC
    variable = disp_x
    boundary = left_left
    value = 0
  []
  [confine_right]
    type = DirichletBC
    variable = disp_x
    boundary = right_right
    value = 0
  []
  [push_down]
    type = FunctionDirichletBC
    variable = disp_y
    boundary = 'left_top right_top'
    function = '-1e-3 * t'
  []
[]

[AuxVariables]
  [contact_force_y]
    block = '1 2 3'
  []
[]

[AuxKernels]
  [contact_force_y]
    type = TagVectorAux
    variable = contact_force_y
    v = disp_y
    vector_tag = contact_force
    block = '1 2 3'
  []
[]

[Postprocessors]
  [left_bottom_force]
    type = MortarContactForce
    weighted_gap_uo = lm_weightedgap_object_mortar_p_base_top_s_left_bottom
    component = y
  []
  [right_bottom_force]
    type = MortarContactForce
    weighted_gap_uo = lm_weightedgap_object_mortar_p_base_top_s_right_bottom
    component = y
  []
  [left_bottom_force_magnitude]
    type = MortarContactForce
    weighted_gap_uo = lm_weightedgap_object_mortar_p_base_top_s_left_bottom
  []
  [left_bottom_nodal_sum]
    type = NodalSum
    variable = contact_force_y
    boundary = left_bottom
  []
  [right_bottom_nodal_sum]
    type = NodalSum
    variable = contact_force_y
    boundary = right_bottom
  []
[]

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

[Executioner]
  type = Transient
  solve_type = NEWTON
  petsc_options_iname = '-pc_type -pc_factor_shift_type'
  petsc_options_value = 'lu       NONZERO'
  dt = 1
  end_time = 2
  nl_abs_tol = 1e-10
[]

[Outputs]
  csv = true
[]

Overview
Example Input File Syntax
Input Parameters
Input Files