FunctionPointForce

This class applies a force at the given point/points in a given direction. The force can be given as a function of space and/or time.

Description

The points at which the force needs to be applied can be supplied in two ways: (i) a single point can be specified as a vector using "point" and (ii) multiple points can be specified by providing the "x_position", "y_position" and "z_position" as three seperate functions and providing the total number of points in "number".

This class then distributes this point force to the nodes of the element that this point belongs to.

Input Parameters

functionThe function defining the force as a function of space and/or time
C++ Type:FunctionName
Unit:(no unit assumed)
Controllable:No
Description:The function defining the force as a function of space and/or time
variableThe name of the variable that this residual object operates on
C++ Type:NonlinearVariableName
Unit:(no unit assumed)
Controllable:No
Description:The name of the variable that this residual object operates on

Required Parameters

allow_moving_sourcesFalseIf true, allow Dirac sources to move, even if the mesh does not move, during the simulation.
Default:False
C++ Type:bool
Controllable:No
Description:If true, allow Dirac sources to move, even if the mesh does not move, during the simulation.
alpha0The Hilber Hughes Taylor (HHT) time integration parameter.
Default:0
C++ Type:double
Unit:(no unit assumed)
Controllable:No
Description:The Hilber Hughes Taylor (HHT) time integration parameter.
blockThe list of blocks (ids or names) that this object will be applied
C++ Type:std::vector<SubdomainName>
Controllable:No
Description:The list of blocks (ids or names) that this object will be applied
matrix_onlyFalseWhether this object is only doing assembly to matrices (no vectors)
Default:False
C++ Type:bool
Controllable:No
Description:Whether this object is only doing assembly to matrices (no vectors)
numberThe number of points.
C++ Type:unsigned int
Controllable:No
Description:The number of points.
pointThe x,y,z coordinates of the point.
C++ Type:std::vector<double>
Unit:(no unit assumed)
Controllable:No
Description:The x,y,z coordinates of the point.
point_not_found_behaviorIGNOREBy default (IGNORE), it is ignored if an added point cannot be located in the specified subdomains. If this option is set to ERROR, this situation will result in an error. If this option is set to WARNING, then a warning will be issued.
Default:IGNORE
C++ Type:MooseEnum
Options:ERROR, WARNING, IGNORE
Controllable:No
Description:By default (IGNORE), it is ignored if an added point cannot be located in the specified subdomains. If this option is set to ERROR, this situation will result in an error. If this option is set to WARNING, then a warning will be issued.
x_positionThe function containing the x coordinates of the points. The first column gives point number (starting with 1) and second column gives x coordinate.
C++ Type:FunctionName
Unit:(no unit assumed)
Controllable:No
Description:The function containing the x coordinates of the points. The first column gives point number (starting with 1) and second column gives x coordinate.
y_positionThe function containing the y coordinates of the points. The first column gives point number (starting with 1) and second column gives y coordinate.
C++ Type:FunctionName
Unit:(no unit assumed)
Controllable:No
Description:The function containing the y coordinates of the points. The first column gives point number (starting with 1) and second column gives y coordinate.
z_positionThe function containing the z coordinates of the points. The first column gives point number (starting with 1) and second column gives z coordinate.
C++ Type:FunctionName
Unit:(no unit assumed)
Controllable:No
Description:The function containing the z coordinates of the points. The first column gives point number (starting with 1) and second column gives z coordinate.

Optional Parameters

absolute_value_vector_tagsThe tags for the vectors this residual object should fill with the absolute value of the residual contribution
C++ Type:std::vector<TagName>
Controllable:No
Description:The tags for the vectors this residual object should fill with the absolute value of the residual contribution
extra_matrix_tagsThe extra tags for the matrices this Kernel should fill
C++ Type:std::vector<TagName>
Controllable:No
Description:The extra tags for the matrices this Kernel should fill
extra_vector_tagsThe extra tags for the vectors this Kernel should fill
C++ Type:std::vector<TagName>
Controllable:No
Description:The extra tags for the vectors this Kernel should fill
matrix_tagssystemThe tag for the matrices this Kernel should fill
Default:system
C++ Type:MultiMooseEnum
Options:nontime, system
Controllable:No
Description:The tag for the matrices this Kernel should fill
vector_tagsnontimeThe tag for the vectors this Kernel should fill
Default:nontime
C++ Type:MultiMooseEnum
Options:nontime, time
Controllable:No
Description:The tag for the vectors this Kernel should fill

Contribution To Tagged Field Data Parameters

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.
drop_duplicate_pointsTrueBy default points added to a DiracKernel are dropped if a point at the same locationhas been added before. If this option is set to false duplicate points are retainedand contribute to residual and Jacobian.
Default:True
C++ Type:bool
Controllable:No
Description:By default points added to a DiracKernel are dropped if a point at the same locationhas been added before. If this option is set to false duplicate points are retainedand contribute to residual and Jacobian.
enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Controllable:Yes
Description:Set the enabled status of the MooseObject.
implicitTrueDetermines whether this object is calculated using an implicit or explicit form
Default:True
C++ Type:bool
Controllable:No
Description:Determines whether this object is calculated using an implicit or explicit form
seed0The seed for the master random number generator
Default:0
C++ Type:unsigned int
Controllable:No
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
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

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
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.

Material Property Retrieval Parameters

Input Files

(test/tests/dirackernels/function_point_force/force_one_point.i)
(test/tests/dirackernels/function_point_force/force_multi_point.i)
(test/tests/dirackernels/function_point_force/force_error.i)

(test/tests/dirackernels/function_point_force/force_one_point.i)

# Test for function point force for force applied at one point.

# This test consists of one quad4 element of size 1x1.
# Node 0 - (0.5,0.5)
# Node 1 - (-0.5, 0.5)
# Node 2 - (-0.5, -0.5)
# Node 3 - (0.5, -0.5)

# A linearly increasing force time history (F) in applied in the y direction at 0.25,0.25.
# This force is applied through dirackernels. DiracKernels distribute this force to the
# four nodes weighted by closeness of the node to the point at which the force is applied.
# The force distributed to node 0 is 0.75*0.75*F, node 1 is 0.25*0.75*F, node 2 is 0.25*0.25*F
# node 4 is 0.75*0.25*F.
#
# To check if forces are distributed as expected, we apply negative of these nodal forces to the
# nodal points using nodalkernels.
# Result: Net force on the element is zero. So element should be in equilibrium with zero displacements.

[Mesh]
  file = test_element.e
[]


[Variables]
  [./disp_x]
  [../]
  [./disp_y]
  [../]
[]

[Kernels]
  [./DynamicTensorMechanics]
    displacements = 'disp_x disp_y'
  [../]
[]

[DiracKernels]
  [./force_y]
    type = FunctionPointForce
    variable = disp_y
    point = '0.25 0.25'
    function = y_force
  [../]
[]

[NodalKernels]
  [./force_1]
    type = UserForcingFunctionNodalKernel
    variable = disp_y
    boundary = 1 # node 2
    function = force_1
  [../]
  [./force_2]
    type = UserForcingFunctionNodalKernel
    variable = disp_y
    boundary = 2 # node 3
    function = force_2
  [../]
  [./force_3]
    type = UserForcingFunctionNodalKernel
    variable = disp_y
    boundary = 3 # node 0
    function = force_3
  [../]
  [./force_4]
    type = UserForcingFunctionNodalKernel
    variable = disp_y
    boundary = 4 # node 1
    function = force_4
  [../]
[]

[Materials]
  [./Elasticity_tensor_1]
    type = ComputeIsotropicElasticityTensor
    block = 1
    youngs_modulus = 2.e+2
    poissons_ratio = 0.4
  [../]

  [./strain_1]
    type = ComputeSmallStrain
    block = 1
    displacements = 'disp_x disp_y'
  [../]

  [./stress_1]
    type = ComputeLinearElasticStress
    block = 1
  [../]

  [./density_1]
    type = GenericConstantMaterial
    block = 1
    prop_names = 'density'
    prop_values = '1.'
  [../]

[]

[Executioner]
  type = Transient
  solve_type = 'PJFNK'
  start_time = 0
  end_time = 5.0
  l_tol = 1e-10
  nl_abs_tol = 1e-12
  dt = 1.0
  timestep_tolerance = 1e-12
[]

[Functions]
  [./y_force]
    type = PiecewiseLinear
    x = '0.0 1.0 2.0 3.0 4.0 5.0'
    y = '0.0 1.0 2.0 3.0 4.0 5.0'
  [../]
  [./force_1]
    type = PiecewiseLinear
    x = '0.0 1.0 2.0 3.0 4.0 5.0'
    y = '0.0 1.0 2.0 3.0 4.0 5.0'
    scale_factor = -0.0625
  [../]
  [./force_2]
    type = PiecewiseLinear
    x = '0.0 1.0 2.0 3.0 4.0 5.0'
    y = '0.0 1.0 2.0 3.0 4.0 5.0'
    scale_factor = -0.1875
  [../]
  [./force_3]
    type = PiecewiseLinear
    x = '0.0 1.0 2.0 3.0 4.0 5.0'
    y = '0.0 1.0 2.0 3.0 4.0 5.0'
    scale_factor = -0.5625
  [../]
  [./force_4]
    type = PiecewiseLinear
    x = '0.0 1.0 2.0 3.0 4.0 5.0'
    y = '0.0 1.0 2.0 3.0 4.0 5.0'
    scale_factor = -0.1875
  [../]
[]

[Postprocessors]
  [./_dt]
    type = TimestepSize
  [../]
  [./disp_1]
    type = NodalVariableValue
    nodeid = 0
    variable = disp_x
  [../]
  [./disp_2]
    type = NodalVariableValue
    nodeid = 0
    variable = disp_y
  [../]
[]

[Outputs]
  exodus = true
  csv = true
  print_linear_residuals = true
  perf_graph = true
  [./console]
    type = Console
    output_linear = true
  [../]
[]

(test/tests/dirackernels/function_point_force/force_multi_point.i)

# Test for function point force applied at multiple points.

# This test consists of one quad4 element of size 1x1.
# Node 0 - (0.5,0.5)
# Node 1 - (-0.5, 0.5)
# Node 2 - (-0.5, -0.5)
# Node 3 - (0.5, -0.5)

# A linearly increasing force time history (F) in applied in the y direction at (0.25,0.25),
# (0.25,-0.25), (-0.25, 0.25) and (-0.25,-0.25).

# This force is applied through dirackernels. DiracKernels distribute this force to the
# four nodes weighted by closeness of the node to the point at which the force is applied.
# The force distributed to node 0 is 0.75*0.75*F, node 1 is 0.25*0.75*F, node 2 is 0.25*0.25*F
# node 4 is 0.75*0.25*F for F applied at (0.25,0.25).
# Repeating this for all the nodes, the total force at each node will be equal to
# (0.75*0.75 + 0.25*0.75 + 0.75*0.25 + 0.25*0.25)*F = 1.0*F
#
# To check if forces are distributed as expected, we apply negative of these nodal forces to the
# nodes using nodalkernels.
# Result: Net force on the element is zero. So element should be in equilibrium with zero displacements.

[Mesh]
  file = test_element.e
[]


[Variables]
  [./disp_x]
  [../]
  [./disp_y]
  [../]
[]

[Kernels]
  [./DynamicTensorMechanics]
    displacements = 'disp_x disp_y'
  [../]
[]

[DiracKernels]
  [./force_y]
    type = FunctionPointForce
    variable = disp_y
    x_position = x_pos
    y_position = y_pos
    number = 4 # number of point sources
    function = y_force
  [../]
[]

[NodalKernels]
  [./force_1]
    type = UserForcingFunctionNodalKernel
    variable = disp_y
    boundary = 1 # node 2
    function = force_1
  [../]
  [./force_2]
    type = UserForcingFunctionNodalKernel
    variable = disp_y
    boundary = 2 # node 3
    function = force_2
  [../]
  [./force_3]
    type = UserForcingFunctionNodalKernel
    variable = disp_y
    boundary = 3 # node 0
    function = force_3
  [../]
  [./force_4]
    type = UserForcingFunctionNodalKernel
    variable = disp_y
    boundary = 4 # node 1
    function = force_4
  [../]
[]

[Materials]
  [./Elasticity_tensor_1]
    type = ComputeIsotropicElasticityTensor
    block = 1
    youngs_modulus = 2.e+2
    poissons_ratio = 0.4
  [../]

  [./strain_1]
    type = ComputeSmallStrain
    block = 1
    displacements = 'disp_x disp_y'
  [../]

  [./stress_1]
    type = ComputeLinearElasticStress
    block = 1
  [../]

  [./density_1]
    type = GenericConstantMaterial
    block = 1
    prop_names = 'density'
    prop_values = '1.'
  [../]

[]

[Executioner]
  type = Transient
  solve_type = 'PJFNK'
  start_time = 0
  end_time = 5.0
  l_tol = 1e-10
  nl_abs_tol = 1e-12
  dt = 1.0
  timestep_tolerance = 1e-12
[]

[Functions]
  [./y_force]
    type = PiecewiseLinear
    x = '0.0 1.0 2.0 3.0 4.0 5.0'
    y = '0.0 1.0 2.0 3.0 4.0 5.0'
  [../]
  [./force_1]
    type = PiecewiseLinear
    x = '0.0 1.0 2.0 3.0 4.0 5.0'
    y = '0.0 1.0 2.0 3.0 4.0 5.0'
    scale_factor = -1.0
  [../]
  [./force_2]
    type = PiecewiseLinear
    x = '0.0 1.0 2.0 3.0 4.0 5.0'
    y = '0.0 1.0 2.0 3.0 4.0 5.0'
    scale_factor = -1.0
  [../]
  [./force_3]
    type = PiecewiseLinear
    x = '0.0 1.0 2.0 3.0 4.0 5.0'
    y = '0.0 1.0 2.0 3.0 4.0 5.0'
    scale_factor = -1.0
  [../]
  [./force_4]
    type = PiecewiseLinear
    x = '0.0 1.0 2.0 3.0 4.0 5.0'
    y = '0.0 1.0 2.0 3.0 4.0 5.0'
    scale_factor = -1.0
  [../]
  [./x_pos]
    type = PiecewiseLinear
    x = '1      2    3     4' # point number
    y = '0.25 0.25 -0.25 -0.25' # x position of the points
  [../]
  [./y_pos]
    type = PiecewiseLinear
    x = '1      2    3     4' # point number
    y = '0.25 -0.25 0.25 -0.25' # y position of the points
  [../]
[]

[Postprocessors]
  [./_dt]
    type = TimestepSize
  [../]
  [./disp_1]
    type = NodalVariableValue
    nodeid = 0
    variable = disp_x
  [../]
  [./disp_2]
    type = NodalVariableValue
    nodeid = 0
    variable = disp_y
  [../]
[]

[Outputs]
  exodus = true
  csv = true
  print_linear_residuals = true
  perf_graph = true
  [./console]
    type = Console
    output_linear = true
  [../]
[]

(test/tests/dirackernels/function_point_force/force_error.i)

[Mesh]
  type = GeneratedMesh
  dim = 3
[]

[Variables]
  [./u]
  [../]
[]

[DiracKernels]
  [./src]
    type = FunctionPointForce
    function = 'x'
    variable = u
  [../]
[]

[Problem]
  kernel_coverage_check = false
[]

[Executioner]
  type = Transient
  num_steps = 1
[]

[Outputs]
[]

Description
Input Parameters
Input Files

Usage

Development

Demonstration