- displacementsThe displacements appropriate for the simulation geometry and coordinate system
C++ Type:std::vector<VariableName>
Controllable:No
Description:The displacements appropriate for the simulation geometry and coordinate system
Compute Plane Finite Strain
Compute strain increment and rotation increment for finite strain under 2D planar assumptions.
Description
The material ComputePlaneFiniteStrain calculates the finite strain for 2D plane strain problems. It can be used for classical plane strain or plane stress problems, or in Generalized Plane Strain simulations.
Out of Plane Strain
In the classical plane strain problem, it is assumed that the front and back surfaces of the body are constrained in the out-of-plane direction, and that the displacements in that direction on those surfaces are zero. As a result, the strain and deformation gradient components in the out-of-plane direction are held constant at zero: (1) is the deformation gradient tensor diagonal component for the direction of the out-of-plane strain and is the corresponding strain component.
Plane Stress and Generalized Plane Strain
In the cases of the plane stress and generalized plane strain assumptions, the component of strain and the deformation gradient in the out-of-plane direction is non-zero. To solve for this out-of-plane strain, we invoke the approximation of the stretch rate tensor (2) and define the deformation gradient component in the out-of-plane direction as (3) where is the deformation gradient tensor diagonal component for the direction of the out-of-plane strain and is a prescribed out-of-plane strain value: this strain value can be given either as a scalar variable or a nonlinear field variable.
For the case of plane stress, the WeakPlaneStress kernel is used to integrate the out-of-plane component of the stress over the area of each element, and assemble that integral to the residual of the out-of-plane strain field variable. This results in a weak enforcement of the condition that the out-of-plane stress is zero, which allows for re-use of the same constitutive models for models of all dimensionality.
The Generalized Plane Strain problems use scalar variables. Multiple scalar variables can be provided such that one strain calculator is needed for multiple generalized plane strain models on different subdomains.
Strain and Deformation Gradient Formulation
The incremental deformation gradient for the 2D planar system is defined as (4) where is the Rank-2 identity tensor, is the deformation gradient, and is the old deformation gradient.
-Direction of Out-of-Plane Strain (Default)
The default out-of-plane direction is along the -axis. For this direction the current and old deformation gradient tensors, used in Eq. (4), are given as (5) where is defined in Eq. (3). Note that uses the values of the strain expressions from the previous time step. As in the classical presentation of the strain tensor in plane strain problems, the components of the deformation tensor associated with the -direction are zero; these zero components indicate no coupling between the in-plane displacements and the out-of-plane strain variable.
-Direction of Out-of-Plane Strain
If the user selects the out-of-plane direction as along the -direction, the current and old deformation gradient tensors from Eq. (4) are formulated as (6) so that the off-diagonal components of the deformation tensors associated with the -direction are zeros.
-Direction of Out-of-Plane Strain
If the user selects the out-of-plane direction as along the -direction, the current and old deformation gradient tensors from Eq. (4) are formulated as (7) so that the off-diagonal components of the deformation tensors associated with the -direction are zeros.
Finalized Deformation Gradient
If selected by the user, the incremental deformation gradient is conditioned with a formulation to mitigate volumetric locking of the elements. The volumetric locking correction is applied to both the incremental deformation gradient (8) and the total deformation gradient. For more details about the theory behind Eq. (8) see the Volumetric Locking Correction documentation.
Once the incremental deformation gradient is calculated for the specific 2D geometry, the deformation gradient is passed to the strain and rotation methods used by the 3D Cartesian simulations, as described in the Finite Strain Class documentation.
Example Input Files
Plane Stress
The tensor mechanics Master action can be used to create the ComputePlaneFiniteStrain class by setting planar_formulation = WEAK_PLANE_STRESS and strain = FINITE in the Master action block.
[Modules/TensorMechanics/Master]
[Modules/TensorMechanics/Master]
[Modules/TensorMechanics/Master]
[plane_stress]
planar_formulation = WEAK_PLANE_STRESS
strain = FINITE
generate_output = 'stress_xx stress_xy stress_yy stress_zz strain_xx strain_xy strain_yy'
eigenstrain_names = eigenstrain
[]
[]
[]
[]
Note that for plane stress analysis, the out_of_plane_strain parameter must be defined, and is the name of the out-of-plane strain field variable.
[./strain_zz]
[../]
In the case of this example, out_of_plane_strain is defined in the GlobalParams block.
Generalized Plane Strain
The use of this plane strain class for Generalized Plane Strain simulations uses the scalar out-of-plane strains. The tensor mechanics Master action is used to create the ComputePlaneFiniteStrain class with the planar_formulation = GENERALIZED_PLANE_STRAIN and the strain = FINITE settings.
[./all]
strain = FINITE
add_variables = true
generate_output = 'stress_xx stress_xy stress_yy stress_zz strain_xx strain_xy strain_yy strain_zz'
planar_formulation = GENERALIZED_PLANE_STRAIN
eigenstrain_names = eigenstrain
scalar_out_of_plane_strain = scalar_strain_zz
temperature = temp
save_in = 'saved_x saved_y'
[../]
Note that the argument for the scalar_out_of_plane_strain parameter is the name of the scalar strain variable
[./scalar_strain_zz]
order = FIRST
family = SCALAR
[../]
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
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.
- decomposition_methodTaylorExpansionMethods to calculate the strain and rotation increments
Default:TaylorExpansion
C++ Type:MooseEnum
Controllable:No
Description:Methods to calculate the strain and rotation increments
- eigenstrain_namesList of eigenstrains to be applied in this strain calculation
C++ Type:std::vector<MaterialPropertyName>
Controllable:No
Description:List of eigenstrains to be applied in this strain calculation
- global_strainOptional material property holding a global strain tensor applied to the mesh as a whole
C++ Type:MaterialPropertyName
Controllable:No
Description:Optional material property holding a global strain tensor applied to the mesh as a whole
- out_of_plane_directionzThe direction of the out-of-plane strain.
Default:z
C++ Type:MooseEnum
Controllable:No
Description:The direction of the out-of-plane strain.
- out_of_plane_strainNonlinear variable for plane stress condition
C++ Type:std::vector<VariableName>
Controllable:No
Description:Nonlinear variable for plane stress condition
- 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.
- scalar_out_of_plane_strainScalar variable for generalized plane strain
C++ Type:std::vector<VariableName>
Controllable:No
Description:Scalar variable for generalized plane strain
- subblock_index_providerSubblockIndexProvider user object name
C++ Type:UserObjectName
Controllable:No
Description:SubblockIndexProvider user object name
- volumetric_locking_correctionFalseFlag to correct volumetric locking
Default:False
C++ Type:bool
Controllable:No
Description:Flag to correct volumetric locking
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