ElectrostaticContactCondition

Interface condition that describes the current continuity and contact conductance across a boundary formed between two dissimilar materials (resulting in a potential discontinuity). Conductivity on each side of the boundary is defined via the material properties system.

Description

This interface kernel models the conductivity of electric field across a specified boundary between two dissimilar materials, as described by (Cincotti et al., 2007). It accounts for the influence of electrostatic potential differences across the interface, with an appropriate electrical contact conductance coefficient being provided either by the user as a constant scalar number or via a combination of material properties and constants for calculation. The condition being applied is:

$var element = document.getElementById("moose-equation-eb8f48d3-021b-4a70-b7f7-c15ec4fb3366");katex.render(" \\sigma_{el,1} \\frac{\\partial \\phi}{\\partial \\mathbf{r}} \\bigg\\rvert_1 \\cdot \\mathbf{\\hat{n}} = \\sigma_{el,2} \\frac{\\partial \\phi}{\\partial \\mathbf{r}} \\bigg\\rvert_2 \\cdot \\mathbf{\\hat{n}}", element, {displayMode:true,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$

and

$var element = document.getElementById("moose-equation-6623030c-01e4-45e0-89a8-ab734995ef7f");katex.render(" \\sigma_{el,1} \\frac{\\partial \\phi}{\\partial \\mathbf{r}} \\bigg\\rvert_1 \\cdot \\mathbf{\\hat{n}} = -C_E (\\phi_1 - \\phi_2)", element, {displayMode:true,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$

where

$var element = document.getElementById("moose-equation-a5c37ad3-986a-4989-80e7-5cdf40da0466");katex.render("\\sigma_{el, i}", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ is the electrical conductivity of each material along the interface,
$var element = document.getElementById("moose-equation-40db83a9-e57b-48da-81bb-60bf30acdb93");katex.render("C_E", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ is the electrical contact conductance, and
$var element = document.getElementById("moose-equation-97059dcd-9953-445d-ad2d-18296d5e4538");katex.render("\\phi_i", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ is the electrostatic potential of the material at the interface.

The temperature- and mechanical-pressure-dependent electrical contact conductance, given by (Babu et al., 2001), is calculated using:

$var element = document.getElementById("moose-equation-083dca70-e193-4d0d-9335-fd212f536fd5");katex.render(" C_E(T, P) = \\alpha_E \\sigma_{el,Harm} \\bigg( \\frac{P}{H_{Harm}} \\bigg)^{\\beta_E}", element, {displayMode:true,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$

where

$var element = document.getElementById("moose-equation-2ec1e616-62b3-4bed-8823-c68389935309");katex.render("\\alpha_E", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ is an experimentally-derived proportional fit parameter (set to be 64, from (Cincotti et al., 2007)),
$var element = document.getElementById("moose-equation-5712f6b2-68f4-4f5b-bea3-6099b8e648aa");katex.render("\\sigma_{el,Harm}", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ is the harmonic mean of the temperature-dependent electrical conductivities on either side of the boundary,
$var element = document.getElementById("moose-equation-e4c3a30d-e25f-4f1d-aa4d-564410351b9f");katex.render("P", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ ( $var element = document.getElementById("moose-equation-005d86cb-32fa-41ad-8d81-42fc25ccb6b2");katex.render("=F/S", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ ) is the uniform mechanical pressure applied at the contact surface area (S) between the two materials,
$var element = document.getElementById("moose-equation-0f005d43-fb01-4b57-b29c-99ed099ec6a8");katex.render("H_{Harm}", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ is the harmonic mean of the hardness values of each material, and
$var element = document.getElementById("moose-equation-3a6accbc-14f2-4101-bb3d-b2210db40784");katex.render("\\beta_E", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ is an experimentally-derived power fit parameter (set to be 0.35, from (Cincotti et al., 2007)).

For reference, the harmonic mean calculation for two values, $var element = document.getElementById("moose-equation-e3e1fcee-5b91-407b-a9a8-64f6bdbaf731");katex.render("V_a", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ and $var element = document.getElementById("moose-equation-c995ef5e-0c85-4bb2-b536-0511fbd5b017");katex.render("V_b", element, {displayMode:false,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$ , is given by

$var element = document.getElementById("moose-equation-140470b9-4ef1-46c0-9441-2b9c15603976");katex.render(" V_{Harm} = \\frac{2 V_a V_b}{V_a + V_b}", element, {displayMode:true,throwOnError:false,macros:{"\\eqc":"\\,,","\\eqp":"\\,.","\\pd":"\\frac{\\partial #1}{\\partial #2}","\\pr":"\\left(#1\\right)","\\ddt":"\\frac{d #1}{d t}"}});$

warning:Order of variables matters!

Please note that variable must always refer to the variable of higher potential, while the neighbor_var must always refer to the variable of lower potential in your model. Knowledge of your boundary conditions (where potential is applied or grounded) and electrical conductivities on either side of the boundary is vital to making the right choice! Please refer to the electromagnetics module test examples as well as (Cincotti et al., 2007) for guidance and usage.

Example Input File Syntax

[InterfaceKernels<<<{"href": "../../syntax/InterfaceKernels/index.html"}>>>]
  [electrostatic_contact]
    type = ElectrostaticContactCondition<<<{"description": "Interface condition that describes the current continuity and contact conductance across a boundary formed between two dissimilar materials (resulting in a potential discontinuity). Conductivity on each side of the boundary is defined via the material properties system.", "href": "ElectrostaticContactCondition.html"}>>>
    variable<<<{"description": "The name of the variable that this residual object operates on"}>>> = potential_stainless_steel
    neighbor_var<<<{"description": "The variable on the other side of the interface."}>>> = potential_graphite
    boundary<<<{"description": "The list of boundaries (ids or names) from the mesh where this object applies"}>>> = ssg_interface
    primary_conductivity<<<{"description": "Conductivity on the primary block."}>>> = electrical_conductivity
    secondary_conductivity<<<{"description": "Conductivity on the secondary block."}>>> = electrical_conductivity
    mean_hardness<<<{"description": "Geometric mean of the hardness of each contacting material."}>>> = mean_hardness
    mechanical_pressure<<<{"description": "Mechanical pressure uniformly applied at the contact surface area (Pressure = Force / Surface Area)."}>>> = 8.52842e10 # resulting contact conductance should be ~1.47e5 as described in Cincotti et al (https://doi.org/10.1002/aic.11102)
  []
[]

Input Parameters

neighbor_varThe variable on the other side of the interface.
C++ Type:std::vector<VariableName>
Unit:(no unit assumed)
Controllable:No
Description:The variable on the other side of the interface.
variableThe name of the variable that this residual object operates on
C++ Type:NonlinearVariableName
Unit:(no unit assumed)
Controllable:No
Description:The name of the variable that this residual object operates on

Required Parameters

boundaryThe list of boundaries (ids or names) from the mesh where this object applies
C++ Type:std::vector<BoundaryName>
Controllable:No
Description:The list of boundaries (ids or names) from the mesh where this object applies
matrix_onlyFalseWhether this object is only doing assembly to matrices (no vectors)
Default:False
C++ Type:bool
Controllable:No
Description:Whether this object is only doing assembly to matrices (no vectors)
mean_hardnessmean_hardnessGeometric mean of the hardness of each contacting material.
Default:mean_hardness
C++ Type:MaterialPropertyName
Unit:(no unit assumed)
Controllable:No
Description:Geometric mean of the hardness of each contacting material.
mechanical_pressure0Mechanical pressure uniformly applied at the contact surface area (Pressure = Force / Surface Area).
Default:0
C++ Type:FunctionName
Unit:(no unit assumed)
Controllable:No
Description:Mechanical pressure uniformly applied at the contact surface area (Pressure = Force / Surface Area).
primary_conductivityelectrical_conductivityConductivity on the primary block.
Default:electrical_conductivity
C++ Type:MaterialPropertyName
Unit:(no unit assumed)
Controllable:No
Description:Conductivity on the primary block.
secondary_conductivityelectrical_conductivityConductivity on the secondary block.
Default:electrical_conductivity
C++ Type:MaterialPropertyName
Unit:(no unit assumed)
Controllable:No
Description:Conductivity on the secondary block.
user_electrical_contact_conductanceUser-supplied electrical contact conductance coefficient.
C++ Type:double
Unit:(no unit assumed)
Controllable:No
Description:User-supplied electrical contact conductance coefficient.

Optional Parameters

absolute_value_vector_tagsThe tags for the vectors this residual object should fill with the absolute value of the residual contribution
C++ Type:std::vector<TagName>
Controllable:No
Description:The tags for the vectors this residual object should fill with the absolute value of the residual contribution
extra_matrix_tagsThe extra tags for the matrices this Kernel should fill
C++ Type:std::vector<TagName>
Controllable:No
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<TagName>
Controllable:No
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
Controllable:No
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
Controllable:No
Description:The tag for the vectors this Kernel should fill

Contribution To Tagged Field Data 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.
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

diag_save_inThe name of auxiliary variables to save this Kernel's diagonal Jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
C++ Type:std::vector<AuxVariableName>
Unit:(no unit assumed)
Controllable:No
Description:The name of auxiliary variables to save this Kernel's diagonal Jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
diag_save_in_var_sideThis parameter must exist if diag_save_in variables are specified and must have the same length as diag_save_in. This vector specifies whether the corresponding aux_var should save-in jacobian contributions from the primary ('p') or secondary side ('s').
C++ Type:MultiMooseEnum
Options:m, s
Controllable:No
Description:This parameter must exist if diag_save_in variables are specified and must have the same length as diag_save_in. This vector specifies whether the corresponding aux_var should save-in jacobian contributions from the primary ('p') or secondary side ('s').
save_inThe name of auxiliary variables to save this Kernel's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
C++ Type:std::vector<AuxVariableName>
Unit:(no unit assumed)
Controllable:No
Description:The name of auxiliary variables to save this Kernel's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
save_in_var_sideThis parameter must exist if save_in variables are specified and must have the same length as save_in. This vector specifies whether the corresponding aux_var should save-in residual contributions from the primary ('p') or secondary side ('s').
C++ Type:MultiMooseEnum
Options:m, s
Controllable:No
Description:This parameter must exist if save_in variables are specified and must have the same length as save_in. This vector specifies whether the corresponding aux_var should save-in residual contributions from the primary ('p') or secondary side ('s').

Residual And Jacobian Debug Output 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/electromagnetics/test/tests/interfacekernels/electrostatic_contact/contact_conductance_supplied.i)
(modules/electromagnetics/test/tests/interfacekernels/electrostatic_contact/contact_conductance_calculated.i)
(modules/electromagnetics/test/tests/interfacekernels/electrostatic_contact/analytic_solution_test_three_block.i)
(modules/electromagnetics/test/tests/interfacekernels/electrostatic_contact/analytic_solution_test_two_block.i)

References

S. S. Babu, M. L. Santella, Z. Feng, B. W. Riemer, and J. W. Cohron. Empirical model of effects of pressure and temperature on electrical contact resistance of metals. Sci Technol Weld Joining, 6(3):126–132, 2001.

@article{babu2001contactresistance,
    author = "Babu, S. S. and Santella, M. L. and Feng, Z. and Riemer, B. W. and Cohron, J. W.",
    title = "Empirical model of effects of pressure and temperature on electrical contact resistance of metals",
    journal = "Sci Technol Weld Joining",
    volume = "6",
    number = "3",
    pages = "126-132",
    year = "2001"
}

A. Cincotti, A. M. Locci, R. Orrù, and G. Cao. Modeling of SPS apparatus: temperature, current and strain distribution with no powders. AIChE Journal, 53(3):703–719, 2007. doi:10.1002/aic.11102.

@article{cincotti2007sps,
    author = "Cincotti, A. and Locci, A. M. and Orrù, R. and Cao, G.",
    title = "Modeling of {SPS} apparatus: Temperature, current and strain distribution with no powders",
    journal = "AIChE Journal",
    volume = "53",
    number = "3",
    pages = "703-719",
    doi = "10.1002/aic.11102",
    year = "2007"
}

(modules/electromagnetics/test/tests/interfacekernels/electrostatic_contact/contact_conductance_calculated.i)

[Mesh]
  [box]
    type = CartesianMeshGenerator
    dim = 2
    dx = '0.5 0.5'
    dy = '0.25 0.5 0.25'
    ix = '20 20'
    iy = '10 20 10'
    subdomain_id = '1 1
                    2 3
                    1 1'
  []
  [rename_subdomains]
    type = RenameBlockGenerator
    input = box
    old_block = '1 2'
    new_block = 'stainless_steel graphite'
  []
  [create_interface]
    type = SideSetsBetweenSubdomainsGenerator
    input = rename_subdomains
    primary_block = stainless_steel
    paired_block = graphite
    new_boundary = 'ssg_interface'
  []
  [delete_block]
    type = BlockDeletionGenerator
    input = create_interface
    block = 3
  []
[]

[Problem]
  coord_type = RZ
[]

[Variables]
  [potential_graphite]
    block = graphite
  []
  [potential_stainless_steel]
    block = stainless_steel
  []
[]

[Kernels]
  [electric_graphite]
    type = ADMatDiffusion
    variable = potential_graphite
    diffusivity = electrical_conductivity
    block = graphite
  []
  [electric_stainless_steel]
    type = ADMatDiffusion
    variable = potential_stainless_steel
    diffusivity = electrical_conductivity
    block = stainless_steel
  []
[]

[BCs]
  [elec_top]
    type = DirichletBC
    variable = potential_stainless_steel
    boundary = top
    value = 1
  []
  [elec_bottom]
    type = DirichletBC
    variable = potential_stainless_steel
    boundary = bottom
    value = 0
  []
[]

[InterfaceKernels]
  [electrostatic_contact]
    type = ElectrostaticContactCondition
    variable = potential_stainless_steel
    neighbor_var = potential_graphite
    boundary = ssg_interface
    primary_conductivity = electrical_conductivity
    secondary_conductivity = electrical_conductivity
    mean_hardness = mean_hardness
    mechanical_pressure = 8.52842e10  # resulting contact conductance should be ~1.47e5 as described in Cincotti et al (https://doi.org/10.1002/aic.11102)
  []
[]

[Materials]
  #graphite
  [sigma_graphite]
    type = ADGenericConstantMaterial
    prop_names = 'electrical_conductivity'
    prop_values = 3.33e2
    block = graphite
  []

  #stainless_steel
  [sigma_stainless_steel]
    type = ADGenericConstantMaterial
    prop_names = 'electrical_conductivity'
    prop_values = 1.429e6
    block = stainless_steel
  []

  #mean hardness
  [harmonic_mean_hardness]
    type = ADGenericConstantMaterial
    prop_names = 'mean_hardness'
    prop_values = 2.4797e9
  []
[]

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

[Executioner]
  type = Steady
  solve_type = PJFNK
  nl_rel_tol = 1e-09
  petsc_options_iname = '-pc_type -ksp_grmres_restart -sub_ksp_type -sub_pc_type -pc_asm_overlap'
  petsc_options_value = 'asm         101   preonly   ilu      1'
  automatic_scaling = true
[]

[Outputs]
  exodus = true
  perf_graph = true
[]

(modules/electromagnetics/test/tests/interfacekernels/electrostatic_contact/contact_conductance_supplied.i)

[Mesh]
  [box]
    type = CartesianMeshGenerator
    dim = 2
    dx = '0.5 0.5'
    dy = '0.25 0.5 0.25'
    ix = '20 20'
    iy = '10 20 10'
    subdomain_id = '1 1
                    2 3
                    1 1'
  []
  [rename_subdomains]
    type = RenameBlockGenerator
    input = box
    old_block = '1 2'
    new_block = 'stainless_steel graphite'
  []
  [create_interface]
    type = SideSetsBetweenSubdomainsGenerator
    input = rename_subdomains
    primary_block = stainless_steel
    paired_block = graphite
    new_boundary = 'ssg_interface'
  []
  [delete_block]
    type = BlockDeletionGenerator
    input = create_interface
    block = 3
  []
[]

[Problem]
  coord_type = RZ
[]

[Variables]
  [potential_graphite]
    block = graphite
  []
  [potential_stainless_steel]
    block = stainless_steel
  []
[]

[Kernels]
  [electric_graphite]
    type = ADMatDiffusion
    variable = potential_graphite
    diffusivity = electrical_conductivity
    block = graphite
  []
  [electric_stainless_steel]
    type = ADMatDiffusion
    variable = potential_stainless_steel
    diffusivity = electrical_conductivity
    block = stainless_steel
  []
[]

[BCs]
  [elec_top]
    type = DirichletBC
    variable = potential_stainless_steel
    boundary = top
    value = 1
  []
  [elec_bottom]
    type = DirichletBC
    variable = potential_stainless_steel
    boundary = bottom
    value = 0
  []
[]

[InterfaceKernels]
  [electrostatic_contact]
    type = ElectrostaticContactCondition
    variable = potential_stainless_steel
    neighbor_var = potential_graphite
    primary_conductivity = electrical_conductivity
    secondary_conductivity = electrical_conductivity
    boundary = ssg_interface
    user_electrical_contact_conductance = 1.47e5 # as described in Cincotti et al (https://doi.org/10.1002/aic.11102)
  []
[]

[Materials]
  #graphite
  [sigma_graphite]
    type = ADGenericConstantMaterial
    prop_names = 'electrical_conductivity'
    prop_values = 3.33e2
    block = graphite
  []

  #stainless_steel
  [sigma_stainless_steel]
    type = ADGenericConstantMaterial
    prop_names = 'electrical_conductivity'
    prop_values = 1.429e6
    block = stainless_steel
  []
[]

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

[Executioner]
  type = Steady
  solve_type = PJFNK
  petsc_options_iname = '-pc_type -ksp_grmres_restart -sub_ksp_type -sub_pc_type -pc_asm_overlap'
  petsc_options_value = 'asm         101   preonly   ilu      1'
  automatic_scaling = true
  nl_rel_tol = 1e-09
[]

[Outputs]
  exodus = true
  perf_graph = true
[]

(modules/electromagnetics/test/tests/interfacekernels/electrostatic_contact/contact_conductance_calculated.i)

[Mesh]
  [box]
    type = CartesianMeshGenerator
    dim = 2
    dx = '0.5 0.5'
    dy = '0.25 0.5 0.25'
    ix = '20 20'
    iy = '10 20 10'
    subdomain_id = '1 1
                    2 3
                    1 1'
  []
  [rename_subdomains]
    type = RenameBlockGenerator
    input = box
    old_block = '1 2'
    new_block = 'stainless_steel graphite'
  []
  [create_interface]
    type = SideSetsBetweenSubdomainsGenerator
    input = rename_subdomains
    primary_block = stainless_steel
    paired_block = graphite
    new_boundary = 'ssg_interface'
  []
  [delete_block]
    type = BlockDeletionGenerator
    input = create_interface
    block = 3
  []
[]

[Problem]
  coord_type = RZ
[]

[Variables]
  [potential_graphite]
    block = graphite
  []
  [potential_stainless_steel]
    block = stainless_steel
  []
[]

[Kernels]
  [electric_graphite]
    type = ADMatDiffusion
    variable = potential_graphite
    diffusivity = electrical_conductivity
    block = graphite
  []
  [electric_stainless_steel]
    type = ADMatDiffusion
    variable = potential_stainless_steel
    diffusivity = electrical_conductivity
    block = stainless_steel
  []
[]

[BCs]
  [elec_top]
    type = DirichletBC
    variable = potential_stainless_steel
    boundary = top
    value = 1
  []
  [elec_bottom]
    type = DirichletBC
    variable = potential_stainless_steel
    boundary = bottom
    value = 0
  []
[]

[InterfaceKernels]
  [electrostatic_contact]
    type = ElectrostaticContactCondition
    variable = potential_stainless_steel
    neighbor_var = potential_graphite
    boundary = ssg_interface
    primary_conductivity = electrical_conductivity
    secondary_conductivity = electrical_conductivity
    mean_hardness = mean_hardness
    mechanical_pressure = 8.52842e10  # resulting contact conductance should be ~1.47e5 as described in Cincotti et al (https://doi.org/10.1002/aic.11102)
  []
[]

[Materials]
  #graphite
  [sigma_graphite]
    type = ADGenericConstantMaterial
    prop_names = 'electrical_conductivity'
    prop_values = 3.33e2
    block = graphite
  []

  #stainless_steel
  [sigma_stainless_steel]
    type = ADGenericConstantMaterial
    prop_names = 'electrical_conductivity'
    prop_values = 1.429e6
    block = stainless_steel
  []

  #mean hardness
  [harmonic_mean_hardness]
    type = ADGenericConstantMaterial
    prop_names = 'mean_hardness'
    prop_values = 2.4797e9
  []
[]

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

[Executioner]
  type = Steady
  solve_type = PJFNK
  nl_rel_tol = 1e-09
  petsc_options_iname = '-pc_type -ksp_grmres_restart -sub_ksp_type -sub_pc_type -pc_asm_overlap'
  petsc_options_value = 'asm         101   preonly   ilu      1'
  automatic_scaling = true
[]

[Outputs]
  exodus = true
  perf_graph = true
[]

(modules/electromagnetics/test/tests/interfacekernels/electrostatic_contact/analytic_solution_test_three_block.i)

# Regression test for ElectrostaticContactCondition with analytic solution with
# three blocks
#
# dim = 1D
# X = [0,3]
# Interfaces at X = 1 and X = 2
#
#   stainless_steel        graphite        stainless_steel
# +------------------+------------------+------------------+
#
# Left BC: Potential = 1
# Right BC: Potential = 0
# Left Interface: ElectrostaticContactCondition (primary = stainless_steel)
# Right Interface: ElectrostaticContactCondition (primary = graphite)
#

[Mesh]
  [line]
    type = GeneratedMeshGenerator
    dim = 1
    nx = 6
    xmax = 3
  []
  [break_center]
    type = SubdomainBoundingBoxGenerator
    input = line
    block_id = 1
    block_name = 'graphite'
    bottom_left = '1 0 0'
    top_right = '2 0 0'
  []
  [break_right]
    type = SubdomainBoundingBoxGenerator
    input = break_center
    block_id = 2
    bottom_left = '2 0 0'
    top_right = '3 0 0'
  []
  [ssg_interface]
    type = SideSetsBetweenSubdomainsGenerator
    input = break_right
    primary_block = 0
    paired_block = 1
    new_boundary = 'ssg_interface'
  []
  [gss_interface]
    type = SideSetsBetweenSubdomainsGenerator
    input = ssg_interface
    primary_block = 1
    paired_block = 2
    new_boundary = 'gss_interface'
  []
  [block_rename]
    type = RenameBlockGenerator
    input = gss_interface
    old_block = '0 2'
    new_block = 'stainless_steel_left stainless_steel_right'
  []
[]

[Variables]
  [potential_graphite]
    block = graphite
  []
  [potential_stainless_steel_left]
    block = stainless_steel_left
  []
  [potential_stainless_steel_right]
    block = stainless_steel_right
  []
[]

[AuxVariables]
  [analytic_potential_stainless_steel_left]
    block = stainless_steel_left
  []
  [analytic_potential_stainless_steel_right]
    block = stainless_steel_right
  []
  [analytic_potential_graphite]
    block = graphite
  []
[]

[Kernels]
  [electric_graphite]
    type = ADMatDiffusion
    variable = potential_graphite
    diffusivity = electrical_conductivity
    block = graphite
  []
  [electric_stainless_steel_left]
    type = ADMatDiffusion
    variable = potential_stainless_steel_left
    diffusivity = electrical_conductivity
    block = stainless_steel_left
  []
  [electric_stainless_steel_right]
    type = ADMatDiffusion
    variable = potential_stainless_steel_right
    diffusivity = electrical_conductivity
    block = stainless_steel_right
  []
[]

[AuxKernels]
  [analytic_function_aux_stainless_steel_left]
    type = FunctionAux
    function = potential_fxn_stainless_steel_left
    variable = analytic_potential_stainless_steel_left
    block = stainless_steel_left
  []
  [analytic_function_aux_stainless_steel_right]
    type = FunctionAux
    function = potential_fxn_stainless_steel_right
    variable = analytic_potential_stainless_steel_right
    block = stainless_steel_right
  []
  [analytic_function_aux_graphite]
    type = FunctionAux
    function = potential_fxn_graphite
    variable = analytic_potential_graphite
    block = graphite
  []
[]

[BCs]
  [elec_left]
    type = ADDirichletBC
    variable = potential_stainless_steel_left
    boundary = left
    value = 1
  []
  [elec_right]
    type = ADDirichletBC
    variable = potential_stainless_steel_right
    boundary = right
    value = 0
  []
[]

[InterfaceKernels]
  [electric_contact_conductance_ssg]
    type = ElectrostaticContactCondition
    variable = potential_stainless_steel_left
    neighbor_var = potential_graphite
    boundary = ssg_interface
    mean_hardness = mean_hardness
    mechanical_pressure = 3000
  []
  [electric_contact_conductance_gss]
    type = ElectrostaticContactCondition
    variable = potential_graphite
    neighbor_var = potential_stainless_steel_right
    boundary = gss_interface
    mean_hardness = mean_hardness
    mechanical_pressure = 3000
  []
[]

[Materials]
  #graphite (at 300 K)
  [sigma_graphite]
    type = ADGenericConstantMaterial
    prop_names = electrical_conductivity
    prop_values = 73069.2
    block = graphite
  []

  #stainless_steel (at 300 K)
  [sigma_stainless_steel_left]
    type = ADGenericConstantMaterial
    prop_names = electrical_conductivity
    prop_values = 1.41867e6
    block = stainless_steel_left
  []
  [sigma_stainless_steel_right]
    type = ADGenericConstantMaterial
    prop_names = electrical_conductivity
    prop_values = 1.41867e6
    block = stainless_steel_right
  []

  # harmonic mean of graphite and stainless steel hardness
  [mean_hardness]
    type = ADGenericConstantMaterial
    prop_names = mean_hardness
    prop_values = 2.4797e9
  []
[]

[Functions]
  [potential_fxn_stainless_steel_left]
    type = ElectricalContactTestFunc
    domain = stainless_steel
    three_block = true
    three_block_side = left
  []
  [potential_fxn_stainless_steel_right]
    type = ElectricalContactTestFunc
    domain = stainless_steel
    three_block = true
    three_block_side = right
  []
  [potential_fxn_graphite]
    type = ElectricalContactTestFunc
    domain = graphite
    three_block = true
  []
[]

[Postprocessors]
  [error_stainless_steel_left]
    type = ElementL2Error
    variable = potential_stainless_steel_left
    function = potential_fxn_stainless_steel_left
    block = stainless_steel_left
  []
  [error_graphite]
    type = ElementL2Error
    variable = potential_graphite
    function = potential_fxn_graphite
    block = graphite
  []
  [error_stainless_steel_right]
    type = ElementL2Error
    variable = potential_stainless_steel_right
    function = potential_fxn_stainless_steel_right
    block = stainless_steel_right
  []
[]


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

[Executioner]
  type = Steady
  solve_type = NEWTON
  automatic_scaling = true
[]

[Outputs]
  csv = true
  perf_graph = true
[]

(modules/electromagnetics/test/tests/interfacekernels/electrostatic_contact/analytic_solution_test_two_block.i)

# Regression test for ElectrostaticContactCondition with analytic solution with
# two blocks
#
# dim = 1D
# X = [0,2]
# Interface at X = 1
#
#   stainless_steel        graphite
# +------------------+------------------+
#
# Left BC: Potential = 1
# Right BC: Potential = 0
# Center Interface: ElectrostaticContactCondition
#

[Mesh]
  [line]
    type = GeneratedMeshGenerator
    dim = 1
    nx = 4
    xmax = 2
  []
  [break]
    type = SubdomainBoundingBoxGenerator
    input = line
    block_id = 1
    block_name = 'graphite'
    bottom_left = '1 0 0'
    top_right = '2 0 0'
  []
  [block_rename]
    type = RenameBlockGenerator
    input = break
    old_block = 0
    new_block = 'stainless_steel'
  []
  [interface]
    type = SideSetsBetweenSubdomainsGenerator
    input = block_rename
    primary_block = 'stainless_steel'
    paired_block = 'graphite'
    new_boundary = 'ssg_interface'
  []
[]

[Variables]
  [potential_graphite]
    block = graphite
  []
  [potential_stainless_steel]
    block = stainless_steel
  []
[]

[AuxVariables]
  [analytic_potential_stainless_steel]
    block = stainless_steel
  []
  [analytic_potential_graphite]
    block = graphite
  []
[]

[Kernels]
  [electric_graphite]
    type = ADMatDiffusion
    variable = potential_graphite
    diffusivity = electrical_conductivity
    block = graphite
  []
  [electric_stainless_steel]
    type = ADMatDiffusion
    variable = potential_stainless_steel
    diffusivity = electrical_conductivity
    block = stainless_steel
  []
[]

[AuxKernels]
  [analytic_function_aux_stainless_steel]
    type = FunctionAux
    function = potential_fxn_stainless_steel
    variable = analytic_potential_stainless_steel
    block = stainless_steel
  []
  [analytic_function_aux_graphite]
    type = FunctionAux
    function = potential_fxn_graphite
    variable = analytic_potential_graphite
    block = graphite
  []
[]

[BCs]
  [elec_left]
    type = ADDirichletBC
    variable = potential_stainless_steel
    boundary = left
    value = 1
  []
  [elec_right]
    type = ADDirichletBC
    variable = potential_graphite
    boundary = right
    value = 0
  []
[]

[InterfaceKernels]
  [electric_contact_conductance_ssg]
    type = ElectrostaticContactCondition
    variable = potential_stainless_steel
    neighbor_var = potential_graphite
    boundary = ssg_interface
    mean_hardness = mean_hardness
    mechanical_pressure = 3000
  []
[]

[Materials]
  #graphite (at 300 K)
  [sigma_graphite]
    type = ADGenericConstantMaterial
    prop_names = electrical_conductivity
    prop_values = 73069.2
    block = graphite
  []

  #stainless_steel (at 300 K)
  [sigma_stainless_steel]
    type = ADGenericConstantMaterial
    prop_names = electrical_conductivity
    prop_values = 1.41867e6
    block = stainless_steel
  []

  # harmonic mean of graphite and stainless steel hardness
  [mean_hardness]
    type = ADGenericConstantMaterial
    prop_names = mean_hardness
    prop_values = 2.4797e9
  []
[]

[Functions]
  [potential_fxn_stainless_steel]
    type = ElectricalContactTestFunc
    domain = stainless_steel
  []
  [potential_fxn_graphite]
    type = ElectricalContactTestFunc
    domain = graphite
  []
[]

[Postprocessors]
  [error_stainless_steel]
    type = ElementL2Error
    variable = potential_stainless_steel
    function = potential_fxn_stainless_steel
    block = stainless_steel
  []
  [error_graphite]
    type = ElementL2Error
    variable = potential_graphite
    function = potential_fxn_graphite
    block = graphite
  []
[]


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

[Executioner]
  type = Steady
  solve_type = NEWTON
  automatic_scaling = true
[]

[Outputs]
  csv = true
  perf_graph = true
[]

Description
Example Input File Syntax
Input Parameters
Input Files
References