Compute Strain Increment Based Stress

Compute stress after subtracting inelastic strain increments

Description

This stress calculator finds the value of the stress as a function of the elastic strain increment when a series of inelastic strains are specified in the input file. The stress is calculated as $(1)var element = document.getElementById("moose-equation-ce608384-6837-4a07-87f9-2f1426cc04fa");katex.render(" \\sigma_{ij} = \\sigma_{ij}^{old} + C_{ijkl} \\Delta \\epsilon_{jk}^{el}", element, {displayMode:true,throwOnError:false});$ where $var element = document.getElementById("moose-equation-de1f9bec-98a0-4c3f-9263-3255641a8f8f");katex.render("\\sigma_{ij}", element, {displayMode:false,throwOnError:false});$ is the stress and $var element = document.getElementById("moose-equation-eb8bb7fc-d029-4350-afa9-a7c6c37f9cad");katex.render("C_{ijkl}", element, {displayMode:false,throwOnError:false});$ is the elasticity tensor of the material. The elastic strain increment, $var element = document.getElementById("moose-equation-cecc111d-6b0d-4ceb-bfcd-74657500bddd");katex.render("\\Delta \\epsilon_{jk}^{el}", element, {displayMode:false,throwOnError:false});$ is found by subtracting the sum of the inelastic strains from the mechanical strain: $(2)var element = document.getElementById("moose-equation-b3847402-fb18-491d-b62c-977c8e7086b9");katex.render(" \\Delta \\boldsymbol{\\epsilon}^{el} = \\boldsymbol{\\epsilon}^{mech} - \\boldsymbol{\\epsilon}^{mech-old} - \\sum_n \\left( \\boldsymbol{\\epsilon}^{inel}_n - {\\boldsymbol{\\epsilon}^{inel-old}}_n \\right)", element, {displayMode:true,throwOnError:false});$ where $var element = document.getElementById("moose-equation-61f040be-4b5c-46df-9524-2f758f1a4e06");katex.render("\\boldsymbol{\\epsilon}^{mech}", element, {displayMode:false,throwOnError:false});$ is the mechanical strain and $var element = document.getElementById("moose-equation-23cf9f7f-ca74-49f0-9524-0d1c9ffb1e55");katex.render("\\boldsymbol{\\epsilon}^{inel}", element, {displayMode:false,throwOnError:false});$ is the inelastic strain. In the tensor mechanics module mechanical strain is defined as the sum of the elastic and inelastic (e.g. creep and/or plasticity) strains.

Example Input File

[./stress]
  type = ComputeStrainIncrementBasedStress
[../]

Input Parameters

base_nameOptional parameter that allows the user to define multiple mechanics material systems on the same block, i.e. for multiple phases
C++ Type:std::string
Controllable:No
Description:Optional parameter that allows the user to define multiple mechanics material systems on the same block, i.e. for multiple phases
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
boundaryThe list of boundaries (ids or names) from the mesh where this object applies
C++ Type:std::vector<BoundaryName>
Controllable:No
Description:The list of boundaries (ids or names) from the mesh where this object applies
computeTrueWhen false, MOOSE will not call compute methods on this material. The user must call computeProperties() after retrieving the MaterialBase via MaterialBasePropertyInterface::getMaterialBase(). Non-computed MaterialBases are not sorted for dependencies.
Default:True
C++ Type:bool
Controllable:No
Description:When false, MOOSE will not call compute methods on this material. The user must call computeProperties() after retrieving the MaterialBase via MaterialBasePropertyInterface::getMaterialBase(). Non-computed MaterialBases are not sorted for dependencies.
constant_onNONEWhen ELEMENT, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps.When SUBDOMAIN, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped
Default:NONE
C++ Type:MooseEnum
Options:NONE, ELEMENT, SUBDOMAIN
Controllable:No
Description:When ELEMENT, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps.When SUBDOMAIN, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped
declare_suffixAn optional suffix parameter that can be appended to any declared properties. The suffix will be prepended with a '_' character.
C++ Type:MaterialPropertyName
Controllable:No
Description:An optional suffix parameter that can be appended to any declared properties. The suffix will be prepended with a '_' character.
extra_stress_namesMaterial property names of rank two tensors to be added to the stress.
C++ Type:std::vector<MaterialPropertyName>
Controllable:No
Description:Material property names of rank two tensors to be added to the stress.
inelastic_strain_namesNames of inelastic strain properties
C++ Type:std::vector<MaterialPropertyName>
Controllable:No
Description:Names of inelastic strain properties
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
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.

Optional 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.
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

Advanced Parameters

output_propertiesList of material properties, from this material, to output (outputs must also be defined to an output type)
C++ Type:std::vector<std::string>
Controllable:No
Description:List of material properties, from this material, to output (outputs must also be defined to an output type)
outputsnone Vector of output names where you would like to restrict the output of variables(s) associated with this object
Default:none
C++ Type:std::vector<OutputName>
Controllable:No
Description:Vector of output names where you would like to restrict the output of variables(s) associated with this object

Outputs Parameters

References

No citations exist within this document.

(moose/modules/tensor_mechanics/test/tests/plane_stress/weak_plane_stress_incremental.i)

[GlobalParams]
  order = FIRST
  family = LAGRANGE
  displacements = 'disp_x disp_y'
  temperature = temp
  out_of_plane_strain = strain_zz
[]

[Mesh]
  [./square]
    type = GeneratedMeshGenerator
    dim = 2
    nx = 2
    ny = 2
  [../]
[]

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

[AuxVariables]
  [./temp]
  [../]
  [./nl_strain_zz]
    order = CONSTANT
    family = MONOMIAL
  [../]
[]

[Postprocessors]
  [./react_z]
    type = MaterialTensorIntegral
    rank_two_tensor = stress
    index_i = 2
    index_j = 2
  [../]
  [./min_strain_zz]
    type = NodalExtremeValue
    variable = strain_zz
    value_type = min
  [../]
  [./max_strain_zz]
    type = NodalExtremeValue
    variable = strain_zz
    value_type = max
  [../]
[]

[Modules/TensorMechanics/Master]
  [plane_stress]
    planar_formulation = WEAK_PLANE_STRESS
    strain = SMALL
    incremental = true
    generate_output = 'stress_xx stress_xy stress_yy stress_zz strain_xx strain_xy strain_yy'
    eigenstrain_names = eigenstrain
  []
[]

[AuxKernels]
  [./tempfuncaux]
    type = FunctionAux
    variable = temp
    function = tempfunc
    use_displaced_mesh = false
  [../]
  [./strain_zz]
    type = RankTwoAux
    rank_two_tensor = total_strain
    variable = nl_strain_zz
    index_i = 2
    index_j = 2
  [../]
[]

[Functions]
  [./pull]
    type = PiecewiseLinear
    x='0     1   100'
    y='0  0.00  0.00'
  [../]
  [./tempfunc]
    type = ParsedFunction
    expression = '(1 - x) * t'
  [../]
[]

[BCs]
  [./bottomx]
    type = DirichletBC
    boundary = 0
    variable = disp_x
    value = 0.0
  [../]
  [./bottomy]
    type = DirichletBC
    boundary = 0
    variable = disp_y
    value = 0.0
  [../]
[]

[Materials]
  [./elasticity_tensor]
    type = ComputeIsotropicElasticityTensor
    poissons_ratio = 0.3
    youngs_modulus = 1e6
  [../]
  [./thermal_strain]
    type = ComputeThermalExpansionEigenstrain
    thermal_expansion_coeff = 0.02
    stress_free_temperature = 0.5
    eigenstrain_name = eigenstrain
  [../]
  [./stress]
    type = ComputeStrainIncrementBasedStress
  [../]
[]

[Executioner]
  type = Transient

  solve_type = PJFNK
  line_search = none

# controls for linear iterations
  l_max_its = 100
  l_tol = 1e-06

# controls for nonlinear iterations
  nl_max_its = 15
  nl_rel_tol = 1e-14
  nl_abs_tol = 1e-12

# time control
  start_time = 0.0
  dt = 1.0
  dtmin = 1.0
  end_time = 2.0
[]

[Outputs]
  exodus = true
[]