Rank Two Aux

Access a component of a RankTwoTensor

Description

The AuxKernel RankTwoAux is used to save single components of Rank-2 tensors into an AuxVariable for visualization and/or post-processing purposes. An antisymmetric Rank-2 tensor would require nine separate RankTwoAux AuxKernel-AuxVariable pairs to store all of the components of the antisymmetric Rank-2 tensor; six separate AuxKernel-AuxVariable pairs are required to print out all the unique components of a symmetric Rank-2 tensor. Quantities commonly examined with RankTwoAux are stress () and strain ().

The RankTwoAux takes as arguments the values of the index_i and the index_j for the single tensor component to save into an AuxVariable. Eq. (1) shows the index values for each Rank-2 tensor component. (1)

If desired, RankTwoAux can be restricted to save data from a Rank-2 tensor at a single specified quadrature point per element. This option is generally used for debugging purposes.

AuxVariable Order

commentnote:Elemental vs Nodal Visualization of Quadrature Field Values

Results will have different quality based on the AuxVariable:

  • Elemental Constant Monomial Using an AuxVariable with family = MONOMIAL and order = CONSTANT will give a constant value of the AuxVariable for the entire element, which is computed by taking a volume-weighted average of the integration point quantities. This is the default option using SolidMechanics Action and requires the least computational cost.

  • Elemental Higher-order Monomial Using an AuxVariable with family = MONOMIAL and order = FIRST or higher will result in fields that vary linearly (or with higher order) within each element. Because the Exodus mesh format does not support higher-order elemental variables, these AuxVariables are output by libMesh as nodal variables for visualization purposes. Using higher order monomial variables in this way can produce smoother visualizations of results for a properly converged simulation.

  • Nodal Lagrange Using an AuxVariable with family = LAGRANGE will result in a smooth nodal field of the material property, constructed using nodal patch recovery. patch_polynomial_order is set to equal the order of the AuxVariable by default. Use this option for the best (smoothest, most accurate) results, but there is some additional computational cost. Furthermore, this method is suitable only for serial simulations at present.

Example Input File Syntax

[./stress_xy]
  type = RankTwoAux
  rank_two_tensor = stress
  variable = stress_xy
  index_i = 0
  index_j = 1
[../]
(modules/solid_mechanics/test/tests/elastic_patch/elastic_patch.i)

An AuxVariable is required to store the RankTwoAux AuxKernel information. Note that the name of the AuxVariable is used as the argument for the variable input parameter in the RankTwoAux block.

[./stress_xy]
  order = CONSTANT
  family = MONOMIAL
[../]
(modules/solid_mechanics/test/tests/elastic_patch/elastic_patch.i)

Input Parameters

  • index_iThe index i of ij for the tensor to output (0, 1, 2)

    C++ Type:unsigned int

    Unit:(no unit assumed)

    Controllable:No

    Description:The index i of ij for the tensor to output (0, 1, 2)

  • index_jThe index j of ij for the tensor to output (0, 1, 2)

    C++ Type:unsigned int

    Unit:(no unit assumed)

    Controllable:No

    Description:The index j of ij for the tensor to output (0, 1, 2)

  • rank_two_tensorThe rank two material tensor name

    C++ Type:MaterialPropertyName

    Unit:(no unit assumed)

    Controllable:No

    Description:The rank two material tensor name

  • variableThe name of the variable that this object applies to

    C++ Type:AuxVariableName

    Unit:(no unit assumed)

    Controllable:No

    Description:The name of the variable that this object applies to

Required Parameters

  • blockThe list of blocks (ids or names) that this object will be applied

    C++ Type:std::vector<SubdomainName>

    Unit:(no unit assumed)

    Controllable:No

    Description:The list of blocks (ids or names) that this object will be applied

  • boundaryThe list of boundaries (ids or names) from the mesh where this object applies

    C++ Type:std::vector<BoundaryName>

    Unit:(no unit assumed)

    Controllable:No

    Description:The list of boundaries (ids or names) from the mesh where this object applies

  • check_boundary_restrictedTrueWhether to check for multiple element sides on the boundary in the case of a boundary restricted, element aux variable. Setting this to false will allow contribution to a single element's elemental value(s) from multiple boundary sides on the same element (example: when the restricted boundary exists on two or more sides of an element, such as at a corner of a mesh

    Default:True

    C++ Type:bool

    Unit:(no unit assumed)

    Controllable:No

    Description:Whether to check for multiple element sides on the boundary in the case of a boundary restricted, element aux variable. Setting this to false will allow contribution to a single element's elemental value(s) from multiple boundary sides on the same element (example: when the restricted boundary exists on two or more sides of an element, such as at a corner of a mesh

  • execute_onLINEAR TIMESTEP_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:LINEAR TIMESTEP_END

    C++ Type:ExecFlagEnum

    Unit:(no unit assumed)

    Options:XFEM_MARK, FORWARD, ADJOINT, HOMOGENEOUS_FORWARD, ADJOINT_TIMESTEP_BEGIN, ADJOINT_TIMESTEP_END, NONE, INITIAL, LINEAR, NONLINEAR_CONVERGENCE, NONLINEAR, POSTCHECK, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM, PRE_DISPLACE

    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.

  • 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

    Unit:(no unit assumed)

    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.

Optional Parameters

  • control_tagsAdds user-defined labels for accessing object parameters via control logic.

    C++ Type:std::vector<std::string>

    Unit:(no unit assumed)

    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

    Unit:(no unit assumed)

    Controllable:Yes

    Description:Set the enabled status of the MooseObject.

  • patch_polynomial_orderPolynomial order used in least squares fitting of material property over the local patch of elements connected to a given node

    C++ Type:MooseEnum

    Unit:(no unit assumed)

    Options:CONSTANT, FIRST, SECOND, THIRD, FOURTH

    Controllable:No

    Description:Polynomial order used in least squares fitting of material property over the local patch of elements connected to a given node

  • seed0The seed for the master random number generator

    Default:0

    C++ Type:unsigned int

    Unit:(no unit assumed)

    Controllable:No

    Description:The seed for the master random number generator

  • selected_qpEvaluate the tensor at this specific quadpoint

    C++ Type:unsigned int

    Unit:(no unit assumed)

    Controllable:No

    Description:Evaluate the tensor at this specific quadpoint

  • 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

    Unit:(no unit assumed)

    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

Input Files