TotalLagrangianStressDivergence

Enforce equilibrium with a total Lagrangian formulation in Cartesian coordinates.

Description

The TotalLagrangianStressDivergence kernel calculates the stress equilibrium residual in the reference configuration using the pk1_stress (the 1st Piola-Kirchhoff stress). This kernel provides the residual for Cartesian coordinates and the user needs to add one kernel for each dimension of the problem. Alternatively, the TensorMechanics/MasterAction simplifies the process of adding the required kernels and setting up the input parameters.

Residual, Jacobian, and stabilization

For large deformation kinematics the kernel applies the residual giving the weak form of the divergence of the 1st Piola Kirchhoff stress with respect to the reference coordinates $var element = document.getElementById("moose-equation-eac14776-c9d0-49de-a091-ac7082a79403");katex.render(" R^{\\alpha}=\\int_{V}P_{iK}\\phi_{i,K}^{\\alpha}dV", element, {displayMode:true,throwOnError:false});$ with the corresponding Jacobian $var element = document.getElementById("moose-equation-b1b675c2-6ab9-4965-b536-25026938e5f5");katex.render(" J^{\\alpha\\beta}=\\int_{V}\\phi_{i,J}^{\\alpha}T_{iJkL}^{\\prime}G_{kL}^{\\beta}dV", element, {displayMode:true,throwOnError:false});$ where $var element = document.getElementById("moose-equation-201cfcb7-f63f-4585-9cc1-5ca0870305e1");katex.render("P_{iK}", element, {displayMode:false,throwOnError:false});$ is the first Piola-Kirchhoff stress, $var element = document.getElementById("moose-equation-75b99920-8674-47ec-9e70-53c87ce69387");katex.render(" T_{iJkL}^{\\prime}=\\frac{dP_{iJ}}{dF_{kL}}", element, {displayMode:true,throwOnError:false});$ $var element = document.getElementById("moose-equation-3e46fc92-72c1-4b28-aa65-52df53a014f4");katex.render("\\phi_{i,J}^{\\alpha}", element, {displayMode:false,throwOnError:false});$ are the test function gradients (with respect to the reference coordinates) and $var element = document.getElementById("moose-equation-94847017-227a-4c26-a4be-ade33f473089");katex.render(" G_{iJ}^{\\beta}=\\frac{dF_{iJ}}{d\\Upsilon^{\\beta}}", element, {displayMode:true,throwOnError:false});$ with $var element = document.getElementById("moose-equation-aff7d392-0d1d-4dfb-bdb6-1d28424eb883");katex.render("\\Upsilon^\\beta", element, {displayMode:false,throwOnError:false});$ the discrete (nodal) displacements. For the unstabilized case $var element = document.getElementById("moose-equation-40eb9828-08d2-411f-af7c-22431a285dbf");katex.render(" G_{ij}^{\\beta} = \\psi_{i,J}^{\\beta}", element, {displayMode:true,throwOnError:false});$ with $var element = document.getElementById("moose-equation-43bb9c18-6043-467c-8d39-7154c4af789e");katex.render("\\psi_{i,J}^{\\beta}", element, {displayMode:false,throwOnError:false});$ the trial function gradients with respect to the reference coordinates.

The residual and Jacobian degenerate to $var element = document.getElementById("moose-equation-026f73df-977c-402e-94ef-255a2ab08a96");katex.render(" R^{\\alpha}=\\int_{v}s_{ij}\\phi_{i,j}^{\\alpha}dv", element, {displayMode:true,throwOnError:false});$ and $var element = document.getElementById("moose-equation-875e0ba1-5949-4f47-b504-66bf2163e962");katex.render(" J^{\\alpha\\beta}=\\int_{V}\\phi_{i,j}^{\\alpha}C_{ijkl}g_{kl}^{\\beta}dV", element, {displayMode:true,throwOnError:false});$ for the small deformation case, with $var element = document.getElementById("moose-equation-37b8bbbd-a42e-4d80-acf7-1f665d76f165");katex.render("s_{ij}", element, {displayMode:false,throwOnError:false});$ the small stress, $var element = document.getElementById("moose-equation-38c08c1f-4e1b-4f21-bbc8-58c5a05c7c05");katex.render(" C_{ijkl} = \\frac{\\partial s_{ij}}{\\partial \\varepsilon_{kl}}", element, {displayMode:true,throwOnError:false});$ with $var element = document.getElementById("moose-equation-22230dfd-f4e6-438a-ba1e-c3173d984606");katex.render("\\varepsilon_{kl}", element, {displayMode:false,throwOnError:false});$ the small strain and $var element = document.getElementById("moose-equation-ca1697ad-89bb-499f-99a1-219c093daca9");katex.render(" g_{kl}^{\\beta} = \\psi_{k,l}^{\\beta}", element, {displayMode:true,throwOnError:false});$ for the unstabilized case. The large_kinematics flag controls the kinematic theory.

The constitutive model needs to provide the first Piola-Kirchhoff stress and the derivative of that stress with respect to the deformation gradient. However, the material system provides a common interface to define the constitutive model with any stress and strain measures that are convient, translating the user-defined stress and Jacobian to the correct form automatically.

The kernel is compatible with the $var element = document.getElementById("moose-equation-c25a4dde-db39-470e-bfb8-ee4d072e82f1");katex.render("\\bar{\\boldsymbol{F}}", element, {displayMode:false,throwOnError:false});$ modification of the strains to stabilize the problem for incompressible or nearly incompressible deformation. This form of stabilization does not modify the residual equation, though the modified strain does change the constitutive model stress update. The strain modification does affect the Jacobian by altering the definition of the gradient tensors. With the modified strains applied these become for small deformations $var element = document.getElementById("moose-equation-2f920160-7d07-457d-9725-6f50ce7f9f76");katex.render(" g_{ij}^{\\beta}=\\psi_{i,j}^{\\beta}-\\frac{1}{3}\\left(\\psi_{kk}^{\\beta}-\\bar{\\psi}_{kk}^{\\beta}\\right)\\delta_{ij}", element, {displayMode:true,throwOnError:false});$ with $var element = document.getElementById("moose-equation-57dfb71b-008b-4cef-9e1a-f8ccd8ad0a15");katex.render(" \\bar{\\psi}_{i,j}^{\\beta}=\\frac{1}{v}\\int_{v}\\psi_{i,j}^{\\beta}dv", element, {displayMode:true,throwOnError:false});$ and for large deformations $var element = document.getElementById("moose-equation-147e8c62-b900-46af-be5e-f5f4ff238ac5");katex.render(" G_{iJ}^{\\beta} = \\left(\\frac{\\det\\bar{F}}{\\det F}\\right)^{1/3}\\left[\\psi_{i,J}^{\\beta}-\\frac{1}{3}F_{iJ}\\left(F_{Lk}^{-1}\\psi_{k,L}^{\\beta}-\\bar{F}_{Lk}^{-1}\\bar{\\psi}_{k,L}^{\\beta}\\right)\\right]", element, {displayMode:true,throwOnError:false});$ with $var element = document.getElementById("moose-equation-9e08806b-863d-4bda-9d1e-4e4f85499605");katex.render(" \\bar{\\psi}_{i,J}^{\\beta}=\\frac{1}{V}\\int_{V}\\psi_{i,J}^{\\beta}dV", element, {displayMode:true,throwOnError:false});$ and $var element = document.getElementById("moose-equation-e2043741-45a5-46e4-a2d4-7b0c02ec7b6d");katex.render("\\bar{F}", element, {displayMode:false,throwOnError:false});$ the average deformation gradient, defined in the stabilization system documentation.

Example Input File Syntax

The following illustrates manually including 3D stress equilibrium with the total Lagrangian formulation, using large deformation kinematics.

[Kernels]
  [sdx]
    type = TotalLagrangianStressDivergence
    variable = disp_x
    component = 0
    large_kinematics = true
  []
  [sdy]
    type = TotalLagrangianStressDivergence
    variable = disp_y
    component = 1
    large_kinematics = true
  []
  [sdz]
    type = TotalLagrangianStressDivergence
    variable = disp_z
    component = 2
    large_kinematics = true
  []
[]

Input Parameters

componentWhich direction this kernel acts in
C++ Type:unsigned int
Controllable:No
Description:Which direction this kernel acts in
displacementsThe displacement components
C++ Type:std::vector<VariableName>
Controllable:No
Description:The displacement components
variableThe name of the variable that this residual object operates on
C++ Type:NonlinearVariableName
Controllable:No
Description:The name of the variable that this residual object operates on

Required Parameters

base_nameMaterial property base name
C++ Type:std::string
Controllable:No
Description:Material property base name
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
eigenstrain_namesList of eigenstrains used in the strain calculation. Used for computing their derivatives for off-diagonal Jacobian terms.
C++ Type:std::vector<MaterialPropertyName>
Controllable:No
Description:List of eigenstrains used in the strain calculation. Used for computing their derivatives for off-diagonal Jacobian terms.
large_kinematicsFalseUse large displacement kinematics
Default:False
C++ Type:bool
Controllable:No
Description:Use large displacement kinematics
out_of_plane_strainThe out-of-plane strain variable for weak plane stress formulation.
C++ Type:std::vector<VariableName>
Controllable:No
Description:The out-of-plane strain variable for weak plane stress formulation.
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.
stabilize_strainFalseAverage the volumetric strains
Default:False
C++ Type:bool
Controllable:No
Description:Average the volumetric strains
temperatureThe name of the temperature variable used in the ComputeThermalExpansionEigenstrain. (Not required for simulations without temperature coupling.)
C++ Type:std::vector<VariableName>
Controllable:No
Description:The name of the temperature variable used in the ComputeThermalExpansionEigenstrain. (Not required for simulations without temperature coupling.)

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

Tagging 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.
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>
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.)
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
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>
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.)
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

Advanced Parameters

(moose/modules/tensor_mechanics/test/tests/lagrangian/cartesian/total/patch/large_patch.i)

[Mesh]
  [base]
    type = FileMeshGenerator
    file = 'patch.xda'
  []
  [sets]
    input = base
    type = SideSetsFromPointsGenerator
    new_boundary = 'left right bottom top back front'
    points = '    0 0.5 0.5
                  1 0.5 0.5
                  0.5 0.0 0.5
               '
             '   0.5 1.0 0.5
                  0.5 0.5 0.0
                  0.5 0.5 1.0'
  []
[]

[GlobalParams]
  displacements = 'disp_x disp_y disp_z'
[]

[Variables]
  [disp_x]
  []
  [disp_y]
  []
  [disp_z]
  []
[]

[Kernels]
  [sdx]
    type = TotalLagrangianStressDivergence
    variable = disp_x
    component = 0
    large_kinematics = true
  []
  [sdy]
    type = TotalLagrangianStressDivergence
    variable = disp_y
    component = 1
    large_kinematics = true
  []
  [sdz]
    type = TotalLagrangianStressDivergence
    variable = disp_z
    component = 2
    large_kinematics = true
  []
[]

[AuxVariables]
  [strain_xx]
    order = CONSTANT
    family = MONOMIAL
  []
  [strain_yy]
    order = CONSTANT
    family = MONOMIAL
  []
  [strain_zz]
    order = CONSTANT
    family = MONOMIAL
  []
  [strain_xy]
    order = CONSTANT
    family = MONOMIAL
  []
  [strain_xz]
    order = CONSTANT
    family = MONOMIAL
  []
  [strain_yz]
    order = CONSTANT
    family = MONOMIAL
  []
  [stress_xx]
    order = CONSTANT
    family = MONOMIAL
  []
  [stress_yy]
    order = CONSTANT
    family = MONOMIAL
  []
  [stress_zz]
    order = CONSTANT
    family = MONOMIAL
  []
  [stress_xy]
    order = CONSTANT
    family = MONOMIAL
  []
  [stress_yz]
    order = CONSTANT
    family = MONOMIAL
  []
  [stress_xz]
    order = CONSTANT
    family = MONOMIAL
  []
[]

[AuxKernels]
  [stress_xx]
    type = RankTwoAux
    rank_two_tensor = cauchy_stress
    variable = stress_xx
    index_i = 0
    index_j = 0
    execute_on = timestep_end
  []
  [stress_yy]
    type = RankTwoAux
    rank_two_tensor = cauchy_stress
    variable = stress_yy
    index_i = 1
    index_j = 1
    execute_on = timestep_end
  []
  [stress_zz]
    type = RankTwoAux
    rank_two_tensor = cauchy_stress
    variable = stress_zz
    index_i = 2
    index_j = 2
    execute_on = timestep_end
  []
  [stress_xy]
    type = RankTwoAux
    rank_two_tensor = cauchy_stress
    variable = stress_xy
    index_i = 0
    index_j = 1
    execute_on = timestep_end
  []
  [stress_xz]
    type = RankTwoAux
    rank_two_tensor = cauchy_stress
    variable = stress_xz
    index_i = 0
    index_j = 2
    execute_on = timestep_end
  []
  [stress_yz]
    type = RankTwoAux
    rank_two_tensor = cauchy_stress
    variable = stress_yz
    index_i = 1
    index_j = 2
    execute_on = timestep_end
  []

  [strain_xx]
    type = RankTwoAux
    rank_two_tensor = mechanical_strain
    variable = strain_xx
    index_i = 0
    index_j = 0
    execute_on = timestep_end
  []
  [strain_yy]
    type = RankTwoAux
    rank_two_tensor = mechanical_strain
    variable = strain_yy
    index_i = 1
    index_j = 1
    execute_on = timestep_end
  []
  [strain_zz]
    type = RankTwoAux
    rank_two_tensor = mechanical_strain
    variable = strain_zz
    index_i = 2
    index_j = 2
    execute_on = timestep_end
  []
  [strain_xy]
    type = RankTwoAux
    rank_two_tensor = mechanical_strain
    variable = strain_xy
    index_i = 0
    index_j = 1
    execute_on = timestep_end
  []
  [strain_xz]
    type = RankTwoAux
    rank_two_tensor = mechanical_strain
    variable = strain_xz
    index_i = 0
    index_j = 2
    execute_on = timestep_end
  []
  [strain_yz]
    type = RankTwoAux
    rank_two_tensor = mechanical_strain
    variable = strain_yz
    index_i = 1
    index_j = 2
    execute_on = timestep_end
  []
[]

[BCs]
  [left]
    type = DirichletBC
    preset = true
    variable = disp_x
    boundary = left
    value = 0.0
  []

  [bottom]
    type = DirichletBC
    preset = true
    variable = disp_y
    boundary = bottom
    value = 0.0
  []

  [back]
    type = DirichletBC
    preset = true
    variable = disp_z
    boundary = back
    value = 0.0
  []

  [front]
    type = DirichletBC
    preset = true
    variable = disp_z
    boundary = front
    value = 0.1
  []
[]

[Materials]
  [elastic_tensor]
    type = ComputeIsotropicElasticityTensor
    youngs_modulus = 1000.0
    poissons_ratio = 0.25
  []
  [compute_stress]
    type = ComputeLagrangianLinearElasticStress
    large_kinematics = true
  []
  [compute_strain]
    type = ComputeLagrangianStrain
    large_kinematics = true
  []
[]

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

[Executioner]
  type = Transient
  dt = 1

  solve_type = 'newton'

  petsc_options_iname = -pc_type
  petsc_options_value = lu

  nl_abs_tol = 1e-10
  nl_rel_tol = 1e-10

  end_time = 1
  dtmin = 1.0
[]

[Outputs]
  exodus = true
[]