Tensor Mechanics Master Action System

Set up stress divergence kernels with coordinate system aware logic

The TensorMechanics Master Action is a convenience object that simplifies part of the mechanics system setup. It performs

  • Add StressDivergence Kernels (for the current coordinate system)

  • Add Strain calculation material (for the chosen strain model)

  • Correctly set use of displaced mesh

  • Optional: Setup of displacement variables (with the correct order for the current mesh)

  • Optional: Add AuxVariables and AuxKernels for various tensor components and quantity outputs

  • Optional: Set up out-of-plane stress/strain consistently

Constructed MooseObjects

The Tensor Mechanics Master Action is used to construct the kernels, displacement variables, and strain materials in a consistent manner as required for a continuum mechanics simulation simulation. Optionally it generates aux variables and auxkernels to aid in the output of tensor components and scalar quantities.

Table 1: Correspondence Among Action Functionality and MooseObjects for the Tensor Mechanics Master Action

FunctionalityReplaced ClassesAssociated Parameters
Calculate stress divergence equilibrium for the given coordinate systemStressDivergenceTensors or StressDivergenceRZTensors or StressDivergenceRSphericalTensorsdisplacements : a string of the displacement field variables
Add the displacement variablesVariablesadd_variables: boolean
Calculation of strain for the given coordinate systemComputeFiniteStrain or ComputePlaneFiniteStrain or ComputeAxisymmetric1DFiniteStrain or ComputeAxisymmetricRZFiniteStrainstrain: MooseEnum to select finite or strain formulations
ComputeSmallStrain or ComputePlaneSmallStrain or ComputeAxisymmetric1DSmallStrain or ComputeAxisymmetricRZSmallStrain
ComputeIncrementalSmallStrain or ComputePlaneIncrementalStrain or ComputeAxisymmetric1DIncrementalStrain or ComputeAxisymmetricRZIncrementalStrainincremental : boolean for using a incremental strain formulation
Add AuxVariables and AuxKernels for various tensor component and quantity outputsAuxVariables and RankTwoAux or RankTwoScalarAux or RankFourAuxgenerate_output: a string of the quantities to add

Note that there are many variations for the calculation of the stress divergence and the strain measure. Review the theoretical introduction for the Stress Divergence and the Strain Formulations for more information.

Example Input File Syntax

Subblocks

The subblocks of the Master action are what triggers MOOSE objects to be built. If none of the mechanics is subdomain restricted a single subblock can be used

[./Master]
  [./all]
    strain = FINITE
    add_variables = true
  [../]
[../]
(moose/modules/tensor_mechanics/test/tests/finite_strain_elastic/finite_strain_elastic_new_test.i)

if different mechanics models are needed, multiple subblocks with subdomain restrictions can be used.


[Modules/TensorMechanics/Master]
  # parameters that apply to all subblocks are specified at this level. They
  # can be overwritten in the subblocks.
  add_variables = true
  strain = FINITE
  generate_output = 'stress_xx'

  [./block1]
    # the `block` parameter is only valid insde a subblock.
    block = 1
  [../]
  [./block2]
    block = 2
    # the `additional_generate_output` parameter is also only valid inside a
    # subblock. Values specified here are appended to the `generate_output`
    # parameter values.
    additional_generate_output = 'strain_yy'
  [../]
[]
(moose/modules/tensor_mechanics/test/tests/action/two_block_new.i)

Parameters supplied at the [Modules/TensorMechanics/Master] level act as defaults for the Master action subblocks.

Input Parameters

  • displacementsThe nonlinear displacement variables for the problem

    C++ Type:std::vector

    Description:The nonlinear displacement variables for the problem

Required Parameters

  • decomposition_methodTaylorExpansionMethods to calculate the finite strain and rotation increments

    Default:TaylorExpansion

    C++ Type:MooseEnum

    Description:Methods to calculate the finite strain and rotation increments

  • strain_base_nameThe base name used for the strain. If not provided, it will be set equal to base_name

    C++ Type:std::string

    Description:The base name used for the strain. If not provided, it will be set equal to base_name

  • base_nameMaterial property base name

    C++ Type:std::string

    Description:Material property base name

  • use_displaced_meshFalseWhether to use displaced mesh in the kernels

    Default:False

    C++ Type:bool

    Description:Whether to use displaced mesh in the kernels

  • incrementalFalseUse incremental or total strain

    Default:False

    C++ Type:bool

    Description:Use incremental or total strain

  • eigenstrain_namesList of eigenstrains to be applied in this strain calculation

    C++ Type:std::vector

    Description:List of eigenstrains to be applied in this strain calculation

  • strainSMALLStrain formulation

    Default:SMALL

    C++ Type:MooseEnum

    Description:Strain formulation

  • add_variablesFalseAdd the displacement variables

    Default:False

    C++ Type:bool

    Description:Add the displacement variables

  • inactiveIf specified blocks matching these identifiers will be skipped.

    C++ Type:std::vector

    Description:If specified blocks matching these identifiers will be skipped.

  • volumetric_locking_correctionFalseFlag to correct volumetric locking

    Default:False

    C++ Type:bool

    Description:Flag to correct volumetric locking

  • use_finite_deform_jacobianFalseJacobian for corrotational finite strain

    Default:False

    C++ Type:bool

    Description:Jacobian for corrotational finite strain

  • active__all__ If specified only the blocks named will be visited and made active

    Default:__all__

    C++ Type:std::vector

    Description:If specified only the blocks named will be visited and made active

  • temperatureThe temperature

    C++ Type:NonlinearVariableName

    Description:The temperature

Optional Parameters

  • generate_outputAdd scalar quantity output for stress and/or strain

    C++ Type:MultiMooseEnum

    Description:Add scalar quantity output for stress and/or strain

  • additional_generate_outputAdd scalar quantity output for stress and/or strain (will be appended to the list in `generate_output`)

    C++ Type:MultiMooseEnum

    Description:Add scalar quantity output for stress and/or strain (will be appended to the list in `generate_output`)

Output Parameters

  • save_inThe displacement residuals

    C++ Type:std::vector

    Description:The displacement residuals

  • blockThe list of ids of the blocks (subdomain) that the stress divergence kernels will be applied to

    C++ Type:std::vector

    Description:The list of ids of the blocks (subdomain) that the stress divergence kernels will be applied to

  • diag_save_inThe displacement diagonal preconditioner terms

    C++ Type:std::vector

    Description:The displacement diagonal preconditioner terms

Advanced Parameters

  • scalar_out_of_plane_strainScalar variable for the out-of-plane strain (in y direction for 1D Axisymmetric or in z direction for 2D Cartesian problems)

    C++ Type:NonlinearVariableName

    Description:Scalar variable for the out-of-plane strain (in y direction for 1D Axisymmetric or in z direction for 2D Cartesian problems)

  • out_of_plane_pressure0Function used to prescribe pressure in the out-of-plane direction (y for 1D Axisymmetric or z for 2D Cartesian problems)

    Default:0

    C++ Type:FunctionName

    Description:Function used to prescribe pressure in the out-of-plane direction (y for 1D Axisymmetric or z for 2D Cartesian problems)

  • out_of_plane_directionzThe direction of the out-of-plane strain.

    Default:z

    C++ Type:MooseEnum

    Description:The direction of the out-of-plane strain.

  • planar_formulationNONEOut-of-plane stress/strain formulation

    Default:NONE

    C++ Type:MooseEnum

    Description:Out-of-plane stress/strain formulation

  • pressure_factor1Scale factor applied to prescribed pressure

    Default:1

    C++ Type:double

    Description:Scale factor applied to prescribed pressure

Out-Of-Plane Stress/Strain Parameters

Associated Actions