Torque Reaction

TorqueReaction calculates the torque in 2D and 3Dabout a user-specified axis of rotation centeredat a user-specified origin.

Description

The postprocessor TorqueReaction calculates the applied torque from the reaction forces, coupled as AuxVariables, about a user specified axis of rotation.

TorqueReaction takes a scalar approach to calculating the sum of the acting torques by projecting both the reaction force vector and the position vector (the coordinates of the node upon which the force is applied) onto the axis of rotation and applying the Pythagorean theorem, as in a statics course. This scalar approach allows the postprocessor to accept any axis of rotation direction.

The torque from the reaction forces is calculated, as shown in Eq. (1) relative to the user specified axis of rotation origin and direction. (1) where is the applied reaction force vector, is the current node position, is the origin of the axis of rotation, and is the direction vector of the axis of rotation. The component of the torque acting along the user specified axis of rotation vector, is calculated as Eq. (2): (2) where is the torque vector calculated in Eq. (1) and is the axis of rotation direction vector.

Example Input File Syntax

[./torque]
  type = TorqueReaction
  boundary = right
  reaction_force_variables = 'saved_x saved_y'
  direction_vector = '0. 0. 1.'
[../]
(moose/modules/solid_mechanics/test/tests/torque_reaction/torque_reaction.i)

A list of the AuxVariables which save the reaction forces must be provided to the TorqueReaction block.

[./saved_x]
[../]
(moose/modules/solid_mechanics/test/tests/torque_reaction/torque_reaction.i)
[./saved_y]
[../]
(moose/modules/solid_mechanics/test/tests/torque_reaction/torque_reaction.i)

The reaction force AuxVariables must also be computed using the tagging system to save the reactions to a separate vector in the stress divergence kernel, which is handled in this case using the extra_vector_tags parameter in the QuasiStatic Physics:

[Physics]
  [SolidMechanics]
    [QuasiStatic]
      [master]
        strain = SMALL
        generate_output = 'stress_xx stress_yy'
        add_variables = true
        extra_vector_tags = 'ref'
      []
    []
  []
[]
(moose/modules/solid_mechanics/test/tests/torque_reaction/torque_reaction.i)

The TagVectorAux AuxKernel is used to extract the saved components of the reaction vector from a tagged vector and put them in an AuxVariable. This shows how the component of this is extracted, and the others are handled in a similar manner:

[AuxKernels]
  [saved_x]
    type = TagVectorAux
    vector_tag = 'ref'
    v = 'disp_x'
    variable = 'saved_x'
  []
[]
(moose/modules/solid_mechanics/test/tests/torque_reaction/torque_reaction.i)

Input Parameters

  • direction_vectorThe direction vector of the axis of rotation about which the calculated torque is calculated

    C++ Type:libMesh::VectorValue<double>

    Unit:(no unit assumed)

    Controllable:No

    Description:The direction vector of the axis of rotation about which the calculated torque is calculated

  • reaction_force_variablesThe reaction variables

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

    Unit:(no unit assumed)

    Controllable:No

    Description:The reaction variables

Required Parameters

  • axis_origin0 0 0Origin of the axis of rotation used to calculate the torque

    Default:0 0 0

    C++ Type:libMesh::VectorValue<double>

    Unit:(no unit assumed)

    Controllable:No

    Description:Origin of the axis of rotation used to calculate the torque

  • 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

  • execute_onTIMESTEP_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:TIMESTEP_END

    C++ Type:ExecFlagEnum

    Unit:(no unit assumed)

    Options:NONE, INITIAL, LINEAR, NONLINEAR_CONVERGENCE, NONLINEAR, POSTCHECK, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM, TRANSFER

    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.

  • unique_node_executeFalseWhen false (default), block restricted objects will have the execute method called multiple times on a single node if the node lies on a interface between two subdomains.

    Default:False

    C++ Type:bool

    Unit:(no unit assumed)

    Controllable:No

    Description:When false (default), block restricted objects will have the execute method called multiple times on a single node if the node lies on a interface between two subdomains.

Optional Parameters

  • allow_duplicate_execution_on_initialFalseIn the case where this UserObject is depended upon by an initial condition, allow it to be executed twice during the initial setup (once before the IC and again after mesh adaptivity (if applicable).

    Default:False

    C++ Type:bool

    Unit:(no unit assumed)

    Controllable:No

    Description:In the case where this UserObject is depended upon by an initial condition, allow it to be executed twice during the initial setup (once before the IC and again after mesh adaptivity (if applicable).

  • 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.

  • execution_order_group0Execution order groups are executed in increasing order (e.g., the lowest number is executed first). Note that negative group numbers may be used to execute groups before the default (0) group. Please refer to the user object documentation for ordering of user object execution within a group.

    Default:0

    C++ Type:int

    Unit:(no unit assumed)

    Controllable:No

    Description:Execution order groups are executed in increasing order (e.g., the lowest number is executed first). Note that negative group numbers may be used to execute groups before the default (0) group. Please refer to the user object documentation for ordering of user object execution within a group.

  • force_postauxFalseForces the UserObject to be executed in POSTAUX

    Default:False

    C++ Type:bool

    Unit:(no unit assumed)

    Controllable:No

    Description:Forces the UserObject to be executed in POSTAUX

  • force_preauxFalseForces the UserObject to be executed in PREAUX

    Default:False

    C++ Type:bool

    Unit:(no unit assumed)

    Controllable:No

    Description:Forces the UserObject to be executed in PREAUX

  • force_preicFalseForces the UserObject to be executed in PREIC during initial setup

    Default:False

    C++ Type:bool

    Unit:(no unit assumed)

    Controllable:No

    Description:Forces the UserObject to be executed in PREIC during initial setup

  • outputsVector of output names where you would like to restrict the output of variables(s) associated with this object

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

    Unit:(no unit assumed)

    Controllable:No

    Description:Vector of output names where you would like to restrict the output of variables(s) associated with this object

  • 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

  • use_displaced_meshTrueWhether 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:True

    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