# Compute Reduced Order Eigenstrain

accepts eigenstrains and computes a reduced order eigenstrain for consistency in the order of strain and eigenstrains.

## Description

Since strain is a function of the derivative of displacements, the strain field is one order lower than the displacement field. If the element is linear, the strain field will be constant; if the element is quadratic, the strain field will be linear.

This being the case, eigenstrains that affect the strain need to be of the same order as the strain. A thermal strain taken from temperatures at nodes will vary according to the order of the temperature and not the strain field. Using a thermal strain one order higher than the strain field can lead to oscillations in the overall strain and stress.

This class accepts eigenstrains and computes a reduced order eigenstrain. If the primary solution variable field is linear, the resulting eigenstrain will be constant in an element using volume weighting. If the primary solution variable field is quadratic, the resulting eigenstrain will be linear in an element using a least squares procedure.

## Example Input File syntax


[./reduced_order_eigenstrain]
type = ComputeReducedOrderEigenstrain
input_eigenstrain_names = 'thermal_eigenstrain'
eigenstrain_name = 'reduced_eigenstrain'
[../]
(modules/tensor_mechanics/test/tests/eigenstrain/reducedOrderRZLinear.i)

The eigenstrain_name parameter value must also be set for the strain calculator, and an example parameter setting is shown below:


[Modules]
[./TensorMechanics]
[./Master]
[./all]
strain = SMALL
incremental = true
temperature = temp2
eigenstrain_names = 'reduced_eigenstrain' #'thermal_eigenstrain'
[../]
[../]
[../]
[]
(modules/tensor_mechanics/test/tests/eigenstrain/reducedOrderRZLinear.i)

## Input Parameters

• input_eigenstrain_namesList of eigenstrains to be applied in this strain calculation

C++ Type:std::vector

Options:

Description:List of eigenstrains to be applied in this strain calculation

• eigenstrain_nameMaterial property name for the eigenstrain tensor computed by this model. IMPORTANT: The name of this property must also be provided to the strain calculator.

C++ Type:std::string

Options:

Description:Material property name for the eigenstrain tensor computed by this model. IMPORTANT: The name of this property must also be provided to the strain calculator.

### Required Parameters

• boundaryThe list of boundary IDs from the mesh where this boundary condition applies

C++ Type:std::vector

Options:

Description:The list of boundary IDs from the mesh where this boundary condition applies

• computeTrueWhen false, MOOSE will not call compute methods on this material. The user must call computeProperties() after retrieving the Material via MaterialPropertyInterface::getMaterial(). Non-computed Materials are not sorted for dependencies.

Default:True

C++ Type:bool

Options:

Description:When false, MOOSE will not call compute methods on this material. The user must call computeProperties() after retrieving the Material via MaterialPropertyInterface::getMaterial(). Non-computed Materials are not sorted for dependencies.

• 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

• 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

Options:

Description:Optional parameter that allows the user to define multiple mechanics material systems on the same block, i.e. for multiple phases

### Optional Parameters

• enableTrueSet the enabled status of the MooseObject.

Default:True

C++ Type:bool

Options:

Description:Set the enabled status of the MooseObject.

• 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

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.

• 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.

• seed0The seed for the master random number generator

Default:0

C++ Type:unsigned int

Options:

Description:The seed for the master random number generator

• 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

• 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 computeSubdomainProperties() 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

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 computeSubdomainProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped

• output_propertiesList of material properties, from this material, to output (outputs must also be defined to an output type)

C++ Type:std::vector

Options:

Description:List of material properties, from this material, to output (outputs must also be defined to an output type)

• outputsnone Vector of output names were you would like to restrict the output of variables(s) associated with this object

Default:none

C++ Type:std::vector

Options:

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