ADGravity

Apply gravity. Value is in units of acceleration.

Description

The kernel ADGravity provides a body force term in the stress divergence equilibrium equation to account for ADGravity force due to self weight. In a continuum mechanics problem, momentum conservation is prescribed assuming static equilibrium at each time increment, $var element = document.getElementById("moose-equation-ff98399e-d355-4d23-abe2-2e9555726b3d");katex.render("\\nabla \\cdot \\boldsymbol{\\sigma} + g = 0,", element, {displayMode:true,throwOnError:false,macros:{"\\pf":"\\frac{\\partial #1}{\\partial #2}"}});$ where $var element = document.getElementById("moose-equation-3afd1435-43b9-4e73-ae98-c1e0d3e8fc8c");katex.render("\\boldsymbol{\\sigma}", element, {displayMode:false,throwOnError:false,macros:{"\\pf":"\\frac{\\partial #1}{\\partial #2}"}});$ is the Cauchy stress tensor and $var element = document.getElementById("moose-equation-3078d313-007c-45b0-a056-e9e527d2ace0");katex.render("\\boldsymbol{g}", element, {displayMode:false,throwOnError:false,macros:{"\\pf":"\\frac{\\partial #1}{\\partial #2}"}});$ is the ADGravity body force per unit mass.

Example Input File Syntax

[./gravity_y]
  type = ADGravity
  variable = disp_y
  value = -9.81
[../]

/opt/civet/build_0/moose/modules/tensor_mechanics/test/tests/gravity/ad_gravity_test.i

#
# Gravity Test
#
# This test is designed to apply a gravity body force.
#
# The mesh is composed of one block with a single element.
# The bottom is fixed in all three directions.  Poisson's ratio
# is zero and the density is 20/9.81
# which makes it trivial to check displacements.
#

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

[Mesh]
  type = GeneratedMesh
  dim = 3
[]

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

[Kernels]
  # [./TensorMechanics]
  # [../]
  [./x]
    type = ADStressDivergenceTensors
    variable = disp_x
    component = 0
  [../]
  [./y]
    type = ADStressDivergenceTensors
    variable = disp_y
    component = 1
  [../]
  [./z]
    type = ADStressDivergenceTensors
    variable = disp_z
    component = 2
  [../]
  [./gravity_y]
    type = ADGravity
    variable = disp_y
    value = -9.81
  [../]
[]

[BCs]
  [./no_x]
    type = DirichletBC
    variable = disp_x
    boundary = bottom
    value = 0.0
  [../]
  [./no_y]
    type = DirichletBC
    variable = disp_y
    boundary = bottom
    value = 0.0
  [../]
  [./no_z]
    type = DirichletBC
    variable = disp_z
    boundary = bottom
    value = 0.0
  [../]
[]

[Materials]
  [./Elasticity_tensor]
    type = ComputeElasticityTensor
    fill_method = symmetric_isotropic
    C_ijkl = '0 0.5e6'
  [../]
  [./strain]
    type = ADComputeSmallStrain
    displacements = 'disp_x disp_y disp_z'
  [../]
  [./stress]
    type = ADComputeLinearElasticStress
  [../]
  [./density]
    type = GenericConstantMaterial
    prop_names = density
    prop_values = 2.0387
  [../]
[]

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

[Executioner]
  type = Steady
  solve_type = PJFNK
  nl_abs_tol = 1e-10
  l_max_its = 20
[]

[Outputs]
  [./out]
    type = Exodus
    elemental_as_nodal = true
  [../]
[]

Input Parameters

valueValue multiplied against the residual, e.g. gravitational acceleration
C++ Type:double
Options:
Description:Value multiplied against the residual, e.g. gravitational acceleration
variableThe name of the variable that this Kernel operates on
C++ Type:NonlinearVariableName
Options:
Description:The name of the variable that this Kernel operates on

Required Parameters

alpha0alpha parameter required for HHT time integration scheme
Default:0
C++ Type:double
Options:
Description:alpha parameter required for HHT time integration scheme
blockThe list of block ids (SubdomainID) that this object will be applied
C++ Type:std::vector
Options:
Description:The list of block ids (SubdomainID) that this object will be applied
displacementsThe displacements
C++ Type:std::vector
Options:
Description:The displacements

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.
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
Options:
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
Options:
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
Options:
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
Options:
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
Options:
Description:The seed for the master random number generator
use_displaced_meshTrueDisplaced mesh defaults to true
Default:True
C++ Type:bool
Options:
Description:Displaced mesh defaults to true

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/tensor_mechanics/test/tests/gravity/ad_gravity_test.i
modules/combined/test/tests/exception/ad.i

modules/tensor_mechanics/test/tests/gravity/ad_gravity_test.i

#
# Gravity Test
#
# This test is designed to apply a gravity body force.
#
# The mesh is composed of one block with a single element.
# The bottom is fixed in all three directions.  Poisson's ratio
# is zero and the density is 20/9.81
# which makes it trivial to check displacements.
#

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

[Mesh]
  type = GeneratedMesh
  dim = 3
[]

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

[Kernels]
  # [./TensorMechanics]
  # [../]
  [./x]
    type = ADStressDivergenceTensors
    variable = disp_x
    component = 0
  [../]
  [./y]
    type = ADStressDivergenceTensors
    variable = disp_y
    component = 1
  [../]
  [./z]
    type = ADStressDivergenceTensors
    variable = disp_z
    component = 2
  [../]
  [./gravity_y]
    type = ADGravity
    variable = disp_y
    value = -9.81
  [../]
[]

[BCs]
  [./no_x]
    type = DirichletBC
    variable = disp_x
    boundary = bottom
    value = 0.0
  [../]
  [./no_y]
    type = DirichletBC
    variable = disp_y
    boundary = bottom
    value = 0.0
  [../]
  [./no_z]
    type = DirichletBC
    variable = disp_z
    boundary = bottom
    value = 0.0
  [../]
[]

[Materials]
  [./Elasticity_tensor]
    type = ComputeElasticityTensor
    fill_method = symmetric_isotropic
    C_ijkl = '0 0.5e6'
  [../]
  [./strain]
    type = ADComputeSmallStrain
    displacements = 'disp_x disp_y disp_z'
  [../]
  [./stress]
    type = ADComputeLinearElasticStress
  [../]
  [./density]
    type = GenericConstantMaterial
    prop_names = density
    prop_values = 2.0387
  [../]
[]

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

[Executioner]
  type = Steady
  solve_type = PJFNK
  nl_abs_tol = 1e-10
  l_max_its = 20
[]

[Outputs]
  [./out]
    type = Exodus
    elemental_as_nodal = true
  [../]
[]

modules/combined/test/tests/exception/ad.i

[GlobalParams]
  order = SECOND
  displacements = 'disp_x disp_y'
[]

[Problem]
  coord_type = RZ
[]

[Mesh]
  patch_update_strategy = iteration
  [./gen]
    type = FileMeshGenerator
    file = mesh.e
  [../]
[]

[Variables]
  [./disp_x]
  [../]
  [./disp_y]
  [../]
  [./temp]
    initial_condition = 501
  [../]
[]

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

[Modules/TensorMechanics/Master]
  [./finite]
    strain = FINITE
    use_automatic_differentiation = true
  [../]
[]

[Kernels]
  [./gravity]
    type = ADGravity
    variable = disp_y
    value = -9.81
  [../]
  [./heat]
    type = ADMatDiffusion
    variable = temp
    diffusivity = 1
  [../]
  [./heat_ie]
    type = ADTimeDerivative
    variable = temp
  [../]
[]

[AuxKernels]
  [./conductance]
    type = MaterialRealAux
    property = density
    variable = density_aux
    boundary = inner_surface
  [../]
[]

[ThermalContact]
  [./thermal_contact]
    type = GapHeatTransfer
    variable = temp
    master = outer_interior
    slave = inner_surface
    quadrature = true
  [../]
[]

[BCs]
  [./no_x]
    type = ADDirichletBC
    variable = disp_x
    boundary = 'centerline'
    value = 0.0
  [../]
  [./no_y]
    type = ADDirichletBC
    variable = disp_y
    boundary = 'centerline outer_exterior'
    value = 0.0
  [../]
  [./temp]
    type = FunctionDirichletBC
    boundary = outer_exterior
    variable = temp
    function = '500 + t'
  [../]
[]

[Materials]
  [./density]
    type = GenericConstantMaterial
    prop_names = 'density'
    prop_values = '1'
  [../]

  [./elasticity_tensor]
    type = ComputeIsotropicElasticityTensor
    youngs_modulus = 1e11
    poissons_ratio = 0.3
  [../]

  [./inner_elastic_stress]
    type = ADComputeMultipleInelasticStress
    inelastic_models = 'inner_creep'
    block = inner
    outputs = all
  [../]

  [./inner_creep]
    type = ADPowerLawCreepExceptionTest
    coefficient = 10e-22
    n_exponent = 2
    activation_energy = 0
    block = inner
  [../]

  [./outer_stressstress]
    type = ADComputeFiniteStrainElasticStress
    block = outer
  [../]
[]

[Executioner]
  type = Transient
  petsc_options = ' -snes_converged_reason -ksp_converged_reason'
  petsc_options_iname = '-pc_type'
  petsc_options_value = 'lu'
  line_search = none

  nl_abs_tol = 1e-7
  l_max_its = 20

  num_steps = 1
  dt = 1
  dtmin = .1
[]

[Outputs]
  exodus = true
[]

Description
Example Input File Syntax
Input Parameters
Input Files

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