Line Element Action System

Sets up variables, stress divergence kernels and materials required for a static analysis with beam or truss elements. Also sets up aux variables, aux kernels, and consistent or nodal inertia kernels for dynamic analysis with beam elements.

Description

The LineElement Action is a convenience object that simplifies part of the mechanics/dynamics system setup for beam or truss elements.

Truss Elements: Constructed MooseObjects

The LineElement Action can be used to construct the kernels, strain materials, and displacement variables for a simulation using Truss Elements.

note:Set the Truss Parameter

A truss element is chosen by setting truss = true in the input block.

Table 1: Correspondence Among Action Functionality and MooseObjects for the LineElement Action used in a Truss Elements Simulation

Functionality	Replaced Classes	Associated Parameters
Create truss elements	(none)	`truss = true`
Add the displacement variables	Variables	`add_variables`: boolean
Calculation of stress divergence for a Truss element	StressDivergenceTensorsTruss	`displacements` : a string of the displacement variables

Example Input Syntax (Truss Elements)

[Modules/TensorMechanics/LineElementMaster]
  [Modules/TensorMechanics/LineElementMaster]
    [Modules/TensorMechanics/LineElementMaster]
      [./block]
        truss = true
        add_variables = true
        displacements = 'disp_x disp_y disp_z'

        area = area

        block = '1 2'

        save_in = 'react_x react_y react_z'
      [../]
    []
  []
[]

Beam Elements: Constructed MooseObjects

By default, the LineElement Action sets up the kernels, strain materials, displacement and rotation variables, and auxkernels for a simulation using Beam Elements. It also sets the boolean use_displaced_mesh in a consistent manner for the kernels, nodalkernels, and materials.

Table 2: Correspondence Among Action Functionality and MooseObjects for the LineElement Action used in a Beam Elements Simulation

Functionality	Replaced Classes	Associated Parameters
Add the displacement and rotation variables	Variables	`add_variables`: boolean
Calculation of stress divergence for a Beam element	StressDivergenceBeam	`displacements` : a string of the displacement variables
\|	`rotations`: a string of the rotation variables
Calculation of strain	ComputeIncrementalBeamStrain or ComputeFiniteBeamStrain	`strain_type`: small or large strain formulation
\|	`rotation_type`: small or large rotation formulation
Calculation of inertial forces and moments with consistent mass / inertia matrices	InertialForceBeam	`dynamic_consistent_inertia`: boolean
Calculation of inertial forces using nodal mass	NodalTranslationalInertia	`dynamic_nodal_translational_inertia`: boolean
Calculation of inertial moments using nodal moment of inertia matrix	NodalRotationalInertia	`dynamic_nodal_rotational_inertia`: boolean
Calculation of translational and rotational velocities	NewmarkVelAux	`dynamic_consistent_inertia` or `dynamic_nodal_translational_inertia` or `dynamic_nodal_rotational_inertia` or `add_dynamic_variables`\|
Calculation of translational and rotational accelerations	NewmarkAccelAux	`dynamic_consistent_inertia` or `dynamic_nodal_translational_inertia` or `dynamic_nodal_rotational_inertia` or `add_dynamic_variables`\|

Example Input Syntax (Beam Elements)

[Modules/TensorMechanics/LineElementMaster]
  [Modules/TensorMechanics/LineElementMaster]
    [Modules/TensorMechanics/LineElementMaster]
      # parameters common to all blocks

      add_variables = true
      displacements = 'disp_x disp_y disp_z'
      rotations = 'rot_x rot_y rot_z'

      # Geometry parameters
      area = 0.5
      y_orientation = '0.0 1.0 0.0'

      [./block_1]
        Iy = 1e-5
        Iz = 1e-5
        block = 1
      [../]
      [./block_2]
        Iy = 2e-5
        Iz = 2e-5
        block = 2
      [../]
    []
  []
[]

Subblocks

The subblocks of the LineElement action are what trigger MOOSE objects to be built. If none of the mechanics is subdomain restricted a single subblock should be used, yet if different mechanics models are needed, multiple subblocks with subdomain restrictions can be used.

Parameters supplied at the [Modules/TensorMechanics/LineElementMaster] level act as defaults for all the subblocks within that LineElement block.

Input Parameters

AyFirst moment of area of the beam about y axis. Can be supplied as either a number or a variable name.
C++ Type:std::vector<VariableName>
Controllable:No
Description:First moment of area of the beam about y axis. Can be supplied as either a number or a variable name.
AzFirst moment of area of the beam about z axis. Can be supplied as either a number or a variable name.
C++ Type:std::vector<VariableName>
Controllable:No
Description:First moment of area of the beam about z axis. Can be supplied as either a number or a variable name.
IxSecond moment of area of the beam about x axis. Can be supplied as either a number or a variable name.
C++ Type:std::vector<VariableName>
Controllable:No
Description:Second moment of area of the beam about x axis. Can be supplied as either a number or a variable name.
IySecond moment of area of the beam about y axis. Can be supplied as either a number or a variable name.
C++ Type:std::vector<VariableName>
Controllable:No
Description:Second moment of area of the beam about y axis. Can be supplied as either a number or a variable name.
IzSecond moment of area of the beam about z axis. Can be supplied as either a number or a variable name.
C++ Type:std::vector<VariableName>
Controllable:No
Description:Second moment of area of the beam about z axis. Can be supplied as either a number or a variable name.
accelerationsTranslational acceleration variables
C++ Type:std::vector<VariableName>
Controllable:No
Description:Translational acceleration variables
active__all__ If specified only the blocks named will be visited and made active
Default:__all__
C++ Type:std::vector<std::string>
Controllable:No
Description:If specified only the blocks named will be visited and made active
add_dynamic_variablesFalseAdds translational and rotational velocity and acceleration aux variables and sets up the corresponding AuxKernels for calculating these variables using Newmark time integration. When dynamic_consistent_inertia, dynamic_nodal_rotational_inertia or dynamic_nodal_translational_inertia are set to true, these variables are automatically set up.
Default:False
C++ Type:bool
Controllable:No
Description:Adds translational and rotational velocity and acceleration aux variables and sets up the corresponding AuxKernels for calculating these variables using Newmark time integration. When dynamic_consistent_inertia, dynamic_nodal_rotational_inertia or dynamic_nodal_translational_inertia are set to true, these variables are automatically set up.
add_variablesFalseAdd the displacement variables for truss elements and both displacement and rotation variables for beam elements.
Default:False
C++ Type:bool
Controllable:No
Description:Add the displacement variables for truss elements and both displacement and rotation variables for beam elements.
alpha0alpha parameter for mass dependent numerical damping induced by HHT time integration scheme
Default:0
C++ Type:double
Controllable:No
Description:alpha parameter for mass dependent numerical damping induced by HHT time integration scheme
areaCross-section area of the beam. Can be supplied as either a number or a variable name.
C++ Type:std::vector<VariableName>
Controllable:No
Description:Cross-section area of the beam. Can be supplied as either a number or a variable name.
betabeta parameter for Newmark Time integration
C++ Type:double
Controllable:No
Description:beta parameter for Newmark Time integration
boundaryThe list of boundary IDs from the mesh where the nodal mass/inertia will be applied.
C++ Type:std::vector<BoundaryName>
Controllable:No
Description:The list of boundary IDs from the mesh where the nodal mass/inertia will be applied.
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.
densityName of Material Property or a constant real number defining the density of the beam.
C++ Type:MaterialPropertyName
Controllable:No
Description:Name of Material Property or a constant real number defining the density of the beam.
diag_save_inThe displacement and rotational diagonal preconditioner terms
C++ Type:std::vector<AuxVariableName>
Controllable:No
Description:The displacement and rotational diagonal preconditioner terms
displacementsThe nonlinear displacement variables for the problem
C++ Type:std::vector<VariableName>
Controllable:No
Description:The nonlinear displacement variables for the problem
dynamic_consistent_inertiaFalseIf set to true, consistent mass and inertia matrices are used for the inertial force/torque calculations.
Default:False
C++ Type:bool
Controllable:No
Description:If set to true, consistent mass and inertia matrices are used for the inertial force/torque calculations.
dynamic_nodal_rotational_inertiaFalseIf set to true, nodal inertia matrix is used for the inertial torque calculation.
Default:False
C++ Type:bool
Controllable:No
Description:If set to true, nodal inertia matrix is used for the inertial torque calculation.
dynamic_nodal_translational_inertiaFalseIf set to true, nodal mass matrix is used for the inertial force calculation.
Default:False
C++ Type:bool
Controllable:No
Description:If set to true, nodal mass matrix is used for the inertial force calculation.
eigenstrain_namesList of beam eigenstrains to be applied in this strain calculation.
C++ Type:std::vector<MaterialPropertyName>
Controllable:No
Description:List of beam eigenstrains to be applied in this strain calculation.
eta0Name of material property or a constant real number defining the eta parameter for mass proportional Rayleigh damping.
Default:0
C++ Type:MaterialPropertyName
Controllable:No
Description:Name of material property or a constant real number defining the eta parameter for mass proportional Rayleigh damping.
gammagamma parameter for Newmark Time integration
C++ Type:double
Controllable:No
Description:gamma parameter for Newmark Time integration
inactiveIf specified blocks matching these identifiers will be skipped.
C++ Type:std::vector<std::string>
Controllable:No
Description:If specified blocks matching these identifiers will be skipped.
nodal_IxxNodal moment of inertia in the x direction.
C++ Type:double
Controllable:No
Description:Nodal moment of inertia in the x direction.
nodal_Ixy0Nodal moment of inertia in the xy direction.
Default:0
C++ Type:double
Controllable:No
Description:Nodal moment of inertia in the xy direction.
nodal_Ixz0Nodal moment of inertia in the xz direction.
Default:0
C++ Type:double
Controllable:No
Description:Nodal moment of inertia in the xz direction.
nodal_IyyNodal moment of inertia in the y direction.
C++ Type:double
Controllable:No
Description:Nodal moment of inertia in the y direction.
nodal_Iyz0Nodal moment of inertia in the yz direction.
Default:0
C++ Type:double
Controllable:No
Description:Nodal moment of inertia in the yz direction.
nodal_IzzNodal moment of inertia in the z direction.
C++ Type:double
Controllable:No
Description:Nodal moment of inertia in the z direction.
nodal_massMass associated with the node
C++ Type:double
Controllable:No
Description:Mass associated with the node
nodal_mass_fileThe file containing the nodal positions and the corresponding nodal masses.
C++ Type:FileName
Controllable:No
Description:The file containing the nodal positions and the corresponding nodal masses.
nodal_x_orientationUnit vector along the x direction if different from global x direction.
C++ Type:libMesh::VectorValue<double>
Controllable:No
Description:Unit vector along the x direction if different from global x direction.
nodal_y_orientationUnit vector along the y direction if different from global y direction.
C++ Type:libMesh::VectorValue<double>
Controllable:No
Description:Unit vector along the y direction if different from global y direction.
rotation_typeSMALLRotation formulation
Default:SMALL
C++ Type:MooseEnum
Options:SMALL, FINITE
Controllable:No
Description:Rotation formulation
rotational_accelerationsRotational acceleration variables
C++ Type:std::vector<VariableName>
Controllable:No
Description:Rotational acceleration variables
rotational_velocitiesRotational velocity variables
C++ Type:std::vector<VariableName>
Controllable:No
Description:Rotational velocity variables
rotationsThe rotations appropriate for the simulation geometry and coordinate system
C++ Type:std::vector<VariableName>
Controllable:No
Description:The rotations appropriate for the simulation geometry and coordinate system
save_inThe displacement and rotational residuals
C++ Type:std::vector<AuxVariableName>
Controllable:No
Description:The displacement and rotational residuals
strain_typeSMALLStrain formulation
Default:SMALL
C++ Type:MooseEnum
Options:SMALL, FINITE
Controllable:No
Description:Strain formulation
trussFalseSet to true if the line elements are truss elements instead of the default beam elements.
Default:False
C++ Type:bool
Controllable:No
Description:Set to true if the line elements are truss elements instead of the default beam elements.
use_displaced_meshFalseWhether to use displaced mesh in the kernels
Default:False
C++ Type:bool
Controllable:No
Description:Whether to use displaced mesh in the kernels
velocitiesTranslational velocity variables
C++ Type:std::vector<VariableName>
Controllable:No
Description:Translational velocity variables
y_orientationOrientation of the y direction along which Iyy is provided. This should be perpendicular to the axis of the beam.
C++ Type:libMesh::VectorValue<double>
Controllable:No
Description:Orientation of the y direction along which Iyy is provided. This should be perpendicular to the axis of the beam.
zeta0Name of material property or a constant real number defining the zeta parameter for stiffness proportional Rayleigh damping.
Default:0
C++ Type:MaterialPropertyName
Controllable:No
Description:Name of material property or a constant real number defining the zeta parameter for stiffness proportional Rayleigh damping.

Optional Parameters

blockThe list of ids of the blocks (subdomain) that the stress divergence, inertia kernels and materials will be applied to
C++ Type:std::vector<SubdomainName>
Controllable:No
Description:The list of ids of the blocks (subdomain) that the stress divergence, inertia kernels and materials will be applied to

Advanced Parameters

Associated Actions

Available Actions

Tensor Mechanics App
CommonLineElementActionSets up variables, stress divergence kernels and materials required for a static analysis with beam or truss elements. Also sets up aux variables, aux kernels, and consistent or nodal inertia kernels for dynamic analysis with beam elements.
LineElementActionSets up variables, stress divergence kernels and materials required for a static analysis with beam or truss elements. Also sets up aux variables, aux kernels, and consistent or nodal inertia kernels for dynamic analysis with beam elements.

(../moose/modules/tensor_mechanics/test/tests/truss/truss_3d_action.i)

[Mesh]
  type = FileMesh
  file = truss_3d.e
  displacements = 'disp_x disp_y disp_z'
[]

[AuxVariables]
 [./axial_stress]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./e_over_l]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./area]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./react_x]
    order = FIRST
    family = LAGRANGE
  [../]
  [./react_y]
    order = FIRST
    family = LAGRANGE
  [../]
  [./react_z]
    order = FIRST
    family = LAGRANGE
  [../]
[]

[Functions]
  [./x2]
    type = PiecewiseLinear
    x = '0  1 2 3'
    y = '0 .5 1 1'
  [../]
  [./y2]
    type = PiecewiseLinear
    x = '0 1  2 3'
    y = '0 0 .5 1'
  [../]
[]

[BCs]
  [./fixx1]
    type = DirichletBC
    variable = disp_x
    preset = false
    boundary = 1
    value = 0.0
  [../]
  [./fixx2]
    type = FunctionDirichletBC
    variable = disp_x
    preset = false
    boundary = 2
    function = x2
  [../]
  [./fixx3]
    type = DirichletBC
    variable = disp_x
    preset = false
    boundary = 3
    value = 0.0
  [../]
  [./fixy1]
    type = DirichletBC
    variable = disp_y
    preset = false
    boundary = 1
    value = 0
  [../]
  [./fixy2]
    type = FunctionDirichletBC
    variable = disp_y
    preset = false
    boundary = 2
    function = y2
  [../]
  [./fixy3]
    type = DirichletBC
    variable = disp_y
    preset = false
    boundary = 3
    value = 0
  [../]
  [./fixz1]
    type = DirichletBC
    variable = disp_z
    preset = false
    boundary = 1
    value = 0
  [../]
  [./fixz2]
    type = DirichletBC
    variable = disp_z
    preset = false
    boundary = 2
    value = 0
  [../]
  [./fixz3]
    type = DirichletBC
    variable = disp_z
    preset = false
    boundary = 3
    value = 0
  [../]
[]

[AuxKernels]
  [./axial_stress]
    type = MaterialRealAux
    block = '1 2'
    property = axial_stress
    variable = axial_stress
  [../]
  [./e_over_l]
    type = MaterialRealAux
    block = '1 2'
    property = e_over_l
    variable = e_over_l
  [../]
  [./area]
    type = ConstantAux
    block = '1 2'
    variable = area
    value = 1.0
    execute_on = 'initial timestep_begin'
  [../]
[]

[Executioner]
  type = Transient
  solve_type = PJFNK
  petsc_options_iname = '-pc_type -ksp_gmres_restart'
  petsc_options_value = 'jacobi   101'
  line_search = 'none'

  nl_max_its = 15
  nl_rel_tol = 1e-6
  nl_abs_tol = 1e-10

  dt = 1
  num_steps = 3
  end_time = 3
[]

[Modules/TensorMechanics/LineElementMaster]
  [./block]
    truss = true
    add_variables = true
    displacements = 'disp_x disp_y disp_z'

    area = area

    block = '1 2'

    save_in = 'react_x react_y react_z'
  [../]
[]

[Materials]
  [./linelast]
    type = LinearElasticTruss
    block = '1 2'
    youngs_modulus = 1e6
    displacements = 'disp_x disp_y disp_z'
  [../]
[]

[Outputs]
  file_base = 'truss_3d_out'
  exodus = true
[]

(../moose/modules/tensor_mechanics/test/tests/beam/action/2_block_common.i)

# Test for LineElementAction on multiple blocks by placing parameters
# common to all blocks outside of the individual action blocks

# 2 beams of length 1m are fixed at one end and a force of 1e-4 N
# is applied at the other end of the beams. Beam 1 is in block 1
# and beam 2 is in block 2. All the material properties for the two
# beams are identical. The moment of inertia of beam 2 is twice that
# of beam 1.

# Since the end displacement of a cantilever beam is inversely proportional
# to the moment of inertia, the y displacement at the end of beam 1 should be twice
# that of beam 2.

[Mesh]
  type = FileMesh
  file = 2_beam_block.e
  displacements = 'disp_x disp_y disp_z'
[]

[BCs]
  [./fixx1]
    type = DirichletBC
    variable = disp_x
    boundary = 1
    value = 0.0
  [../]
  [./fixy1]
    type = DirichletBC
    variable = disp_y
    boundary = 1
    value = 0.0
  [../]
  [./fixz1]
    type = DirichletBC
    variable = disp_z
    boundary = 1
    value = 0.0
  [../]
  [./fixr1]
    type = DirichletBC
    variable = rot_x
    boundary = 1
    value = 0.0
  [../]
  [./fixr2]
    type = DirichletBC
    variable = rot_y
    boundary = 1
    value = 0.0
  [../]
  [./fixr3]
    type = DirichletBC
    variable = rot_z
    boundary = 1
    value = 0.0
  [../]
[]

[NodalKernels]
  [./force_1]
    type = ConstantRate
    variable = disp_y
    boundary = 2
    rate = 1e-4
  [../]
[]

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

[Executioner]
  type = Transient
  solve_type = PJFNK
  line_search = 'none'
  nl_max_its = 15
  nl_rel_tol = 1e-10
  nl_abs_tol = 1e-8

  dt = 1
  dtmin = 1
  end_time = 2
[]

[Modules/TensorMechanics/LineElementMaster]
  # parameters common to all blocks

  add_variables = true
  displacements = 'disp_x disp_y disp_z'
  rotations = 'rot_x rot_y rot_z'

  # Geometry parameters
  area = 0.5
  y_orientation = '0.0 1.0 0.0'

  [./block_1]
    Iy = 1e-5
    Iz = 1e-5
    block = 1
  [../]
  [./block_2]
    Iy = 2e-5
    Iz = 2e-5
    block = 2
  [../]
[]

[Materials]
  [./stress]
    type = ComputeBeamResultants
    block = '1 2'
  [../]
  [./elasticity_1]
    type = ComputeElasticityBeam
    youngs_modulus = 2.0
    poissons_ratio = 0.3
    shear_coefficient = 1.0
    block = '1 2'
  [../]
[]

[Postprocessors]
  [./disp_y_1]
    type = PointValue
    point = '1.0 0.0 0.0'
    variable = disp_y
  [../]
  [./disp_y_2]
    type = PointValue
    point = '1.0 1.0 0.0'
    variable = disp_y
  [../]
[]

[Outputs]
  file_base = '2_block_out'
  exodus = true
[]