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.

Example Input File Syntax


[./stress_xy]
  type = RankTwoAux
  rank_two_tensor = stress
  variable = stress_xy
  index_i = 0
  index_j = 1
[../]
(moose/modules/tensor_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
[../]
(moose/modules/tensor_mechanics/test/tests/elastic_patch/elastic_patch.i)
note:Elemental vs Nodal Visualization of Quadrature Field Values

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. 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, which are computed using a local least-squares procedure. 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.

Input Parameters

  • rank_two_tensorThe rank two material tensor name

    C++ Type:MaterialPropertyName

    Description:The rank two material tensor name

  • variableThe name of the variable that this object applies to

    C++ Type:AuxVariableName

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

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

    C++ Type:unsigned int

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

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

    C++ Type:unsigned int

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

Required Parameters

  • execute_onLINEARThe list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM.

    Default:LINEAR

    C++ Type:ExecFlagEnum

    Description:The list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM.

  • boundaryThe list of boundary IDs from the mesh where this boundary condition applies

    C++ Type:std::vector

    Description:The list of boundary IDs from the mesh where this boundary condition applies

  • blockThe list of block ids (SubdomainID) that this object will be applied

    C++ Type:std::vector

    Description:The list of block ids (SubdomainID) that this object will be applied

Optional Parameters

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

    C++ Type:std::vector

    Description:Adds user-defined labels for accessing object parameters via control logic.

  • selected_qpEvaluate the tensor at this specific quadpoint

    C++ Type:unsigned int

    Description:Evaluate the tensor at this specific quadpoint

  • enableTrueSet the enabled status of the MooseObject.

    Default:True

    C++ Type:bool

    Description:Set the enabled status of the MooseObject.

  • seed0The seed for the master random number generator

    Default:0

    C++ Type:unsigned int

    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

    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