StressDivergenceTensorsTruss

Kernel for truss element

Description

This class computes the axial force in the truss local coordinate system using the axial stress and the cross-section area. This local force is then transformed to the global coordinate system using the orientation vector of the truss. The component of the force in the $var element = document.getElementById("moose-equation-bf204607-8f70-4dde-8c7f-a2f1b4e75910");katex.render("i^{th}", element, {displayMode:false,throwOnError:false,macros:{"\\pf":"\\frac{\\partial #1}{\\partial #2}"}});$ global coordinate direction is returned as the residual.

Input Parameters

componentAn integer corresponding to the direction the variable this kernel acts in. (0 for x, 1 for y, 2 for z)
C++ Type:unsigned int
Options:
Description:An integer corresponding to the direction the variable this kernel acts in. (0 for x, 1 for y, 2 for z)
variableThe name of the variable that this Kernel operates on
C++ Type:NonlinearVariableName
Options:
Description:The name of the variable that this Kernel operates on

Required Parameters

areaCross-sectional area of truss element
C++ Type:std::vector
Options:
Description:Cross-sectional area of truss element
base_nameMaterial property base name
C++ Type:std::string
Options:
Description:Material property base name
blockThe list of block ids (SubdomainID) that this object will be applied
C++ Type:std::vector
Options:
Description:The list of block ids (SubdomainID) that this object will be applied
displacementsThe string of displacements suitable for the problem statement
C++ Type:std::vector
Options:
Description:The string of displacements suitable for the problem statement
temperatureThe temperature
C++ Type:std::vector
Options:
Description:The temperature

Optional Parameters

control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector
Options:
Description:Adds user-defined labels for accessing object parameters via control logic.
diag_save_inThe name of auxiliary variables to save this Kernel's diagonal Jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
C++ Type:std::vector
Options:
Description:The name of auxiliary variables to save this Kernel's diagonal Jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Options:
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
Options:
Description:Determines whether this object is calculated using an implicit or explicit form
save_inThe name of auxiliary variables to save this Kernel's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
C++ Type:std::vector
Options:
Description:The name of auxiliary variables to save this Kernel's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
seed0The seed for the master random number generator
Default:0
C++ Type:unsigned int
Options:
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
Options:
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

extra_matrix_tagsThe extra tags for the matrices this Kernel should fill
C++ Type:std::vector
Options:
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
Options:
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
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
Description:The tag for the vectors this Kernel should fill

Tagging Parameters

Input Files

modules/tensor_mechanics/test/tests/truss/truss_2d.i
modules/tensor_mechanics/test/tests/truss/truss_3d.i
modules/tensor_mechanics/test/tests/truss/truss_hex.i
modules/tensor_mechanics/test/tests/truss/truss_plastic.i

modules/tensor_mechanics/test/tests/truss/truss_2d.i

#
# Truss in two dimensional space
#
# The truss is made of five equilateral triangles supported at each end.
# The truss starts at (0,0).  At (1,0), there is a point load of 25.
# The reactions are therefore
#  Ryleft  = 2/3 * 25 = 16.7
#  Ryright = 1/3 * 25 = 8.33
# The area of each member is 0.8.
# Statics gives the stress in each member.  For example, for element 6 (from
#   (0,0) to (1/2,sqrt(3)/2)), the force is
#   f = 2/3 * 25 * 2/sqrt(3) = 100/3/sqrt(3) (compressive)
#   and the stress is
#   s = -100/3/sqrt(3)/0.8 = -24.06
#

[Mesh]
  type = FileMesh
  file = truss_2d.e
  displacements = 'disp_x disp_y'
[]

[Variables]
  [./disp_x]
    order = FIRST
    family = LAGRANGE
  [../]
  [./disp_y]
    order = FIRST
    family = LAGRANGE
  [../]
[]

[AuxVariables]
  [./axial_stress]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./e_over_l]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./area]
    order = CONSTANT
    family = MONOMIAL
#    initial_condition = 1.0
  [../]
  [./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
    boundary = 1
    value = 0
  [../]
  [./fixy1]
    type = DirichletBC
    variable = disp_y
    boundary = 1
    value = 0
  [../]

  [./fixy4]
    type = DirichletBC
    variable = disp_y
    boundary = 4
    value = 0
  [../]
[]

[DiracKernels]
  [./pull]
    type = ConstantPointSource
    value = -25
    point = '1 0 0'
    variable = disp_y
  [../]
[]

[AuxKernels]
  [./axial_stress]
    type = MaterialRealAux
    block = 1
    property = axial_stress
    variable = axial_stress
  [../]
  [./e_over_l]
    type = MaterialRealAux
    block = 1
    property = e_over_l
    variable = e_over_l
  [../]
  [./area]
    type = ConstantAux
    block = 1
    variable = area
    value = 0.8
    execute_on = 'initial timestep_begin'
  [../]
[]

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

[Executioner]
  type = Transient

  solve_type = PJFNK

  petsc_options_iname = '-pc_type -ksp_gmres_restart'
  petsc_options_value = 'jacobi   101'

  nl_max_its = 15
  nl_rel_tol = 1e-8
  nl_abs_tol = 1e-10

  dt = 1
  num_steps = 1
  end_time = 1
[]

[Kernels]
  [./solid_x]
    type = StressDivergenceTensorsTruss
    block = 1
    displacements = 'disp_x disp_y'
    component = 0
    variable = disp_x
    area = area
    save_in = react_x
  [../]
  [./solid_y]
    type = StressDivergenceTensorsTruss
    block = 1
    displacements = 'disp_x disp_y'
    component = 1
    variable = disp_y
    area = area
    save_in = react_y
  [../]
[]

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

[Outputs]
  exodus = true
[]

modules/tensor_mechanics/test/tests/truss/truss_3d.i

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

[Variables]
  [./disp_x]
    order = FIRST
    family = LAGRANGE
  [../]
  [./disp_y]
    order = FIRST
    family = LAGRANGE
  [../]
  [./disp_z]
    order = FIRST
    family = LAGRANGE
  [../]
[]

[AuxVariables]
 [./axial_stress]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./e_over_l]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./area]
    order = CONSTANT
    family = MONOMIAL
#    initial_condition = 1.0
  [../]
  [./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
[]

[Kernels]
  [./solid_x]
    type = StressDivergenceTensorsTruss
    block = '1 2'
    displacements = 'disp_x disp_y disp_z'
    component = 0
    variable = disp_x
    area = area
    save_in = react_x
  [../]
  [./solid_y]
    type = StressDivergenceTensorsTruss
    block = '1 2'
    displacements = 'disp_x disp_y disp_z'
    component = 1
    variable = disp_y
    area = area
    save_in = react_y
  [../]
  [./solid_z]
    type = StressDivergenceTensorsTruss
    block = '1 2'
    displacements = 'disp_x disp_y disp_z'
    component = 2
    variable = disp_z
    area = area
    save_in = react_z
  [../]
[]

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

[Outputs]
  exodus = true
[]

modules/tensor_mechanics/test/tests/truss/truss_hex.i

# This test is designed to check
# whether truss element works well with other multi-dimensional element
# e.g. the hex element in this case, by assigning different brock number
# to different types of elements.
[Mesh]
  type = FileMesh
  file = truss_hex.e
  displacements = 'disp_x disp_y disp_z'
[]

[Variables]
  [./disp_x]
    order = FIRST
    family = LAGRANGE
  [../]
  [./disp_y]
    order = FIRST
    family = LAGRANGE
  [../]
  [./disp_z]
    order = FIRST
    family = LAGRANGE
  [../]
[]

[AuxVariables]
  [./axial_stress]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./e_over_l]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./area]
    order = CONSTANT
    family = MONOMIAL
#    initial_condition = 1.0
  [../]
  [./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
    boundary = 1
    value = 0.0
  [../]
  [./fixy1]
    type = DirichletBC
    variable = disp_y
    boundary = 1
    value = 0
  [../]
  [./fixz1]
    type = DirichletBC
    variable = disp_z
    boundary = 1
    value = 0
  [../]

  [./fixx2]
    type = DirichletBC
    variable = disp_x
    boundary = 2
    value = 0
  [../]
  [./fixz2]
    type = DirichletBC
    variable = disp_z
    boundary = 2
    value = 0
  [../]

  [./fixDummyHex_x]
    type = DirichletBC
    variable = disp_x
    boundary = 1000
    value = 0
  [../]

  [./fixDummyHex_y]
    type = DirichletBC
    variable = disp_y
    boundary = 1000
    value = 0
  [../]

  [./fixDummyHex_z]
    type = DirichletBC
    variable = disp_z
    boundary = 1000
    value = 0
  [../]
[]

[DiracKernels]
  [./pull]
    type = ConstantPointSource
    value = -25
    point = '0 -2 0'
    variable = disp_y
  [../]
[]

[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
  [../]
  [./area1]
    type = ConstantAux
    block = 1
    variable = area
    value = 1.0
    execute_on = 'initial timestep_begin'
  [../]
  [./area2]
    type = ConstantAux
    block = 2
    variable = area
    value = 0.25
    execute_on = 'initial timestep_begin'
  [../]
[]

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

[Executioner]
  type = Transient

  solve_type = PJFNK

  petsc_options_iname = '-pc_type -ksp_gmres_restart'
  petsc_options_value = 'jacobi   101'

  nl_max_its = 15
  nl_rel_tol = 1e-8
  nl_abs_tol = 1e-10

  dt = 1
  num_steps = 1
  end_time = 1
[]

[Kernels]
  [./truss_x]
    type = StressDivergenceTensorsTruss
    block = '1 2'
    variable = disp_x
    displacements = 'disp_x disp_y disp_z'
    component = 0
    area = area
    save_in = react_x
  [../]
  [./truss_y]
    type = StressDivergenceTensorsTruss
    block = '1 2'
    variable = disp_y
    component = 1
    displacements = 'disp_x disp_y disp_z'
    area = area
    save_in = react_y
  [../]
  [./truss_z]
    type = StressDivergenceTensorsTruss
    block = '1 2'
    variable = disp_z
    component = 2
    displacements = 'disp_x disp_y disp_z'
    area = area
    save_in = react_z
  [../]
  [./TensorMechanics]
    block = 1000
    displacements = 'disp_x disp_y disp_z'
  [../]
#  [./hex_x]
#    type = StressDivergenceTensors
#    block = 1000
#    variable = disp_x
#    component = 0
#    displacements = 'disp_x disp_y disp_z'
#  [../]
#  [./hex_y]
#    type = StressDivergenceTensors
#    block = 1000
#    variable = disp_y
#    component = 1
#    displacements = 'disp_x disp_y disp_z'
#  [../]
#  [./hex_z]
#    type = StressDivergenceTensors
#    block = 1000
#    variable = disp_z
#    component = 2
#    displacements = 'disp_x disp_y disp_z'
#  [../]
[]

[Materials]
   [./elasticity_tensor]
    type = ComputeIsotropicElasticityTensor
    block = 1000
    youngs_modulus = 1e6
    poissons_ratio = 0
  [../]
  [./strain]
    type = ComputeSmallStrain
    block = 1000
    displacements = 'disp_x disp_y disp_z'
  [../]
  [./stress]
    type = ComputeLinearElasticStress
    block = 1000
  [../]
  [./linelast]
    type = LinearElasticTruss
    block = '1 2'
    displacements = 'disp_x disp_y disp_z'
    youngs_modulus = 1e6
  [../]
[]

[Outputs]
  exodus = true
[]

modules/tensor_mechanics/test/tests/truss/truss_plastic.i

[Mesh]
  type = GeneratedMesh
  dim = 1
  elem_type = EDGE
  nx = 1
[]

[GlobalParams]
  displacements = 'disp_x'
[]

[Variables]
  [./disp_x]
    order = FIRST
    family = LAGRANGE
  [../]
[]

[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
  [../]
[]

[Functions]
  [./hf]
    type = PiecewiseLinear
    x = '0    0.0001  0.0003  0.0023'
    y = '50e6 52e6    54e6    56e6'
  [../]
[]

[BCs]
  [./fixx1]
    type = DirichletBC
    variable = disp_x
    boundary = left
    value = 0.0
  [../]
  [./load]
    type = FunctionDirichletBC
    variable = disp_x
    boundary = right
    function = 't'
  [../]
[]

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

[Postprocessors]
  [./s_xx]
    type = ElementIntegralMaterialProperty
    mat_prop = axial_stress
  [../]
  [./e_xx]
    type = ElementIntegralMaterialProperty
    mat_prop = total_stretch
  [../]
  [./ee_xx]
    type = ElementIntegralMaterialProperty
    mat_prop = elastic_stretch
  [../]
  [./ep_xx]
    type = ElementIntegralMaterialProperty
    mat_prop = plastic_stretch
  [../]
[]

[Executioner]
  type = Transient
  solve_type = 'PJFNK'
  petsc_options = '-snes_ksp_ew'
  petsc_options_iname = '-pc_type'
  petsc_options_value = 'lu'
  nl_abs_tol = 1e-11
  l_max_its = 20
  dt = 5e-5
  num_steps = 10
[]

[Kernels]
  [./solid]
    type = StressDivergenceTensorsTruss
    component = 0
    variable = disp_x
    area = area
    save_in = react_x
  [../]
[]

[Materials]
  [./truss]
    type = PlasticTruss
    youngs_modulus = 2.0e11
    yield_stress = 500e5
    outputs = exodus
  [../]
[]

[Outputs]
  exodus = true
  csv = true
[]

References

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Input Parameters
Input Files
References

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